Sample records for hydroxyapatite ha microspheres

  1. Scaffolds for bone regeneration made of hydroxyapatite microspheres in a collagen matrix.

    PubMed

    Cholas, Rahmatullah; Kunjalukkal Padmanabhan, Sanosh; Gervaso, Francesca; Udayan, Gayatri; Monaco, Graziana; Sannino, Alessandro; Licciulli, Antonio

    2016-06-01

    Biomimetic scaffolds with a structural and chemical composition similar to native bone tissue may be promising for bone tissue regeneration. In the present work hydroxyapatite mesoporous microspheres (mHA) were incorporated into collagen scaffolds containing an ordered interconnected macroporosity. The mHA were obtained by spray drying of a nano hydroxyapatite slurry prepared by the precipitation technique. X-ray diffraction (XRD) analysis revealed that the microspheres were composed only of hydroxyapatite (HA) phase, and energy-dispersive x-ray spectroscopy (EDS) analysis revealed the Ca/P ratio to be 1.69 which is near the value for pure HA. The obtained microspheres had an average diameter of 6 μm, a specific surface area of 40 m(2)/g as measured by Brunauer-Emmett-Teller (BET) analysis, and Barrett-Joyner-Halenda (BJH) analysis showed a mesoporous structure with an average pore diameter of 16 nm. Collagen/HA-microsphere (Col/mHA) composite scaffolds were prepared by freeze-drying followed by dehydrothermal crosslinking. SEM observations of Col/mHA scaffolds revealed HA microspheres embedded within a porous collagen matrix with a pore size ranging from a few microns up to 200 μm, which was also confirmed by histological staining of sections of paraffin embedded scaffolds. The compressive modulus of the composite scaffold at low and high strain values was 1.7 and 2.8 times, respectively, that of pure collagen scaffolds. Cell proliferation measured by the MTT assay showed more than a 3-fold increase in cell number within the scaffolds after 15 days of culture for both pure collagen scaffolds and Col/mHA composite scaffolds. Attractive properties of this composite scaffold include the potential to load the microspheres for drug delivery and the controllability of the pore structure at various length scales. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Biomimetic composite microspheres of collagen/chitosan/nano-hydroxyapatite: In-situ synthesis and characterization.

    PubMed

    Teng, Shu-Hua; Liang, Mian-Hui; Wang, Peng; Luo, Yong

    2016-01-01

    The collagen/chitosan/hydroxyapatite (COL/CS/HA) composite microspheres with a good spherical form and a high dispersity were successfully obtained using an in-situ synthesis method. The FT-IR and XRD results revealed that the inorganic phase in the microspheres was crystalline HA containing carbonate ions. The morphology of the composite microspheres was dependent on the HA content, and a more desirable morphology was achieved when 20 wt.% HA was contained. The composite microspheres exhibited a narrow particle distribution, most of which ranged from 5 to 10 μm. In addition, the needle-like HA nano-particles were uniformly distributed in the composite microspheres, and their crystallinity and crystal size decreased with the HA content. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Evaluation of BSA protein release from hollow hydroxyapatite microspheres into PEG hydrogel

    PubMed Central

    Fu, Hailuo; Rahaman, Mohamed N.; Brown, Roger F.; Day, Delbert E.

    2013-01-01

    Implants that simultaneously function as an osteoconductive matrix and as a device for local drug or growth factor delivery could provide an attractive system for bone regeneration. In our previous work, we prepared hollow hydroxyapatite (abbreviated HA) microspheres with a high surface area, mesoporous shell wall and studied the release of a model protein, bovine serum albumin (BSA), from the microspheres into phosphate-buffered saline (PBS). The present work is an extension of our previous work to study the release of BSA from similar HA microspheres into a biocompatible hydrogel, poly(ethylene glycol) (PEG). BSA-loaded HA microspheres were placed in a PEG solution which was rapidly gelled using ultraviolet radiation. The BSA release rate into the PEG hydrogel, measured using a spectrophotometric method, was slower than into PBS, and it was dependent on the initial BSA loading and on the microstructure of the microsphere shell wall. A total of 35–40% of the BSA initially loaded into the microspheres was released into PEG over ~14 days. The results indicate that these hollow HA microspheres have promising potential as an osteoconductive device for local drug or growth factor delivery in bone regeneration and in the treatment of bone diseases. PMID:23498254

  4. Hierarchical Microspheres Constructed from Chitin Nanofibers Penetrated Hydroxyapatite Crystals for Bone Regeneration.

    PubMed

    Duan, Bo; Shou, Kangquan; Su, Xiaojuan; Niu, Yahui; Zheng, Guan; Huang, Yao; Yu, Aixi; Zhang, Yu; Xia, Hong; Zhang, Lina

    2017-07-10

    Chitin exists abundantly in crab and shrimp shells as the template of the minerals, which inspired us to mineralize it for fabricating bone grafting materials. In the present work, chitin nanofibrous microspheres were used as the matrix for in situ synthesis of hydroxyapatite (HA) crystals including microflakes, submicron-needles, and submicron-spheres, which were penetrated by long chitin nanofibers, leading to the hierarchical structure. The shape and size of the HA crystals could be controlled by changing the HA synthesis process. The tight interface adhesion between chitin and HA through the noncovanlent bonds occurred in the composite microspheres, and HAs were homogeneously dispersed and bounded to the chitin nanofibers. In our findings, the inherent biocompatibilities of the both chitin and HA contributed the bone cell adhesion and osteoconduction. Moreover, the chitin microsphere with submicron-needle and submicron-sphere HA crystals remarkably promoted in vitro cell adhesion and in vivo bone healing. It was demonstrated that rabbits with 1.5 cm radius defect were almost cured completely within three months in a growth factor- and cell-free state, as a result of the unique surface microstructure and biocompatibilities of the composite microspheres. The microsphere scaffold displayed excellent biofunctions and an appropriate biodegradability. This work opened up a new avenue to construct natural polymer-based organic-inorganic hybrid microspheres for bone regeneration.

  5. In situ fabrication of hollow hydroxyapatite microspheres by phosphate solution immersion

    NASA Astrophysics Data System (ADS)

    Wang, Yingchun; Yao, Aihua; Huang, Wenhai; Wang, Deping; zhou, Jun

    2011-07-01

    Hollow hydroxyapatite (HAP) microspheres with pores on their surfaces were prepared by converting Li 2O-CaO-B 2O 3 (LCB) glass microspheres in phosphate solution. The structure, phase composition, surface morphology, and porosity of the hollow HAP microspheres were characterized by SEM, SEM-EDS, XRD, FTIR, ICP-AES, and N 2 adsorption-desorption techniques. The formation and conversion mechanism of the hollow HAP microspheres during immersion process were discussed. The as-prepared microspheres consisted of calcium deficient carbonated hydroxyapatite, which is biomimetic. FTIR spectra indicated that the resulting apatite were B-type CO 3HAP, in which carbonate ions occupied the phosphate sites. After 600 °C heating treatment, hollow microspheres were completely composed of calcium deficient hydroxyapatite crystals including CO32-. The pore size distribution of the as-prepared hollow HAP microspheres were mainly the mesopores in the range of 2-40 nm with the pore volume 0.5614 cm 3/g, and the mean pore size 10.5 nm, respectively. The results confirmed that LCB glass were transformed to hydroxyapatite without changing the external shape and dimension of the original glass object and the resulting microspheres possessed good hollow structures. Once immersed in phosphate solution, Ca-P-OH hydrates were in situ formed on the surface of the glass and precipitated in the position occupied by Ca 2+, while the pores were formed in the position occupied by Li + and B 3+. These hollow HAP microspheres with such structures may be used as promising drug delivery devices.

  6. Preparation, characterization, and in vitro release of gentamicin from coralline hydroxyapatite-alginate composite microspheres.

    PubMed

    Sivakumar, M; Rao, K Panduranga

    2003-05-01

    In this work, composite microspheres were prepared from bioactive ceramics such as coralline hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2)] granules, a biodegradable polymer, sodium alginate, and an antibiotic, gentamicin. Previously, we have shown a gentamicin release from coralline hydroxyapatite granules-chitosan composite microspheres. In the present investigation, we attempted to prepare composite microspheres containing coralline hydroxyapatite granules and sodium alginate by the dispersion polymerization technique with gentamicin incorporated by absorption method. The crystal structure of the composite microspheres was analyzed using X-ray powder diffractometer. Fourier transform infrared spectra clearly indicated the presence of per-acid of sodium alginate, phosphate, and hydroxyl groups in the composite microspheres. Scanning electron micrographs and optical micrographs showed that the composite microspheres were spherical in shape and porous in nature. The particle size of composite microspheres was analyzed, and the average size was found to be 15 microns. The thermal behavior of composite microspheres was studied using thermogravimetric analysis and differential scanning calorimetric analysis. The cumulative in vitro release profile of gentamicin from composite microspheres showed near zero order patterns. Copyright 2003 Wiley Periodicals, Inc.

  7. BMP2-loaded hollow hydroxyapatite microspheres exhibit enhanced osteoinduction and osteogenicity in large bone defects.

    PubMed

    Xiong, Long; Zeng, Jianhua; Yao, Aihua; Tu, Qiquan; Li, Jingtang; Yan, Liang; Tang, Zhiming

    2015-01-01

    The regeneration of large bone defects is an osteoinductive, osteoconductive, and osteogenic process that often requires a bone graft for support. Limitations associated with naturally autogenic or allogenic bone grafts have demonstrated the need for synthetic substitutes. The present study investigates the feasibility of using novel hollow hydroxyapatite microspheres as an osteoconductive matrix and a carrier for controlled local delivery of bone morphogenetic protein 2 (BMP2), a potent osteogenic inducer of bone regeneration. Hollow hydroxyapatite microspheres (100±25 μm) with a core (60±18 μm) and a mesoporous shell (180±42 m(2)/g surface area) were prepared by a glass conversion technique and loaded with recombinant human BMP2 (1 μg/mg). There was a gentle burst release of BMP2 from microspheres into the surrounding phosphate-buffered saline in vitro within the initial 48 hours, and continued at a low rate for over 40 days. In comparison with hollow hydroxyapatite microspheres without BMP2 or soluble BMP2 without a carrier, BMP2-loaded hollow hydroxyapatite microspheres had a significantly enhanced capacity to reconstitute radial bone defects in rabbit, as shown by increased serum alkaline phosphatase; quick and complete new bone formation within 12 weeks; and great biomechanical flexural strength. These results indicate that BMP2-loaded hollow hydroxyapatite microspheres could be a potential new option for bone graft substitutes in bone regeneration.

  8. BMP2-loaded hollow hydroxyapatite microspheres exhibit enhanced osteoinduction and osteogenicity in large bone defects

    PubMed Central

    Xiong, Long; Zeng, Jianhua; Yao, Aihua; Tu, Qiquan; Li, Jingtang; Yan, Liang; Tang, Zhiming

    2015-01-01

    The regeneration of large bone defects is an osteoinductive, osteoconductive, and osteogenic process that often requires a bone graft for support. Limitations associated with naturally autogenic or allogenic bone grafts have demonstrated the need for synthetic substitutes. The present study investigates the feasibility of using novel hollow hydroxyapatite microspheres as an osteoconductive matrix and a carrier for controlled local delivery of bone morphogenetic protein 2 (BMP2), a potent osteogenic inducer of bone regeneration. Hollow hydroxyapatite microspheres (100±25 μm) with a core (60±18 μm) and a mesoporous shell (180±42 m2/g surface area) were prepared by a glass conversion technique and loaded with recombinant human BMP2 (1 μg/mg). There was a gentle burst release of BMP2 from microspheres into the surrounding phosphate-buffered saline in vitro within the initial 48 hours, and continued at a low rate for over 40 days. In comparison with hollow hydroxyapatite microspheres without BMP2 or soluble BMP2 without a carrier, BMP2-loaded hollow hydroxyapatite microspheres had a significantly enhanced capacity to reconstitute radial bone defects in rabbit, as shown by increased serum alkaline phosphatase; quick and complete new bone formation within 12 weeks; and great biomechanical flexural strength. These results indicate that BMP2-loaded hollow hydroxyapatite microspheres could be a potential new option for bone graft substitutes in bone regeneration. PMID:25609957

  9. Preparation, characterization and in vitro release of gentamicin from coralline hydroxyapatite-gelatin composite microspheres.

    PubMed

    Sivakumar, M; Panduranga Rao, K

    2002-08-01

    Composite microspheres have been prepared from bioactive ceramics such as coralline hydroxyapatite [CHA, Ca10(PO4)6(OH)2] granules, a biodegradable polymer, gelatin and an antibiotic, gentamicin. In our earlier work, we have shown a gentamicin release from CHA granules--chitosan composite microspheres. In the present investigation, an attempt was made to prepare the composite microspheres containing coralline hydroxyapatite and gelatin (CHA-G), which were prepared by the dispersion polymerization technique and the gentamicin was incorporated by the absorption method. The crystal structure of the composite microspheres was analyzed using X-ray powder diffractometer. The Fourier transformed infrared spectrum clearly indicated the presence of amide and hydroxyl groups in the composite microspheres. Scanning electron micrographs and optical micrographs show that the composite microspheres are spherical in shape and porous in nature. The particle size of composite microspheres was analyzed and the average size was found to be 16 microm. The thermal behavior of composite microspheres was studied using thermogravimetric analysis and differential scanning calorimetric analysis. The cumulative in vitro release profile of gentamicin from composite microspheres showed near zero order patterns.

  10. Hydroxyapatite-armored poly(ε-caprolactone) microspheres and hydroxyapatite microcapsules fabricated via a Pickering emulsion route.

    PubMed

    Fujii, Syuji; Okada, Masahiro; Nishimura, Taiki; Maeda, Hayata; Sugimoto, Tatsuya; Hamasaki, Hiroyuki; Furuzono, Tsutomu; Nakamura, Yoshinobu

    2012-05-15

    Hydroxyapatite (HAp) nanoparticle-armored poly(ε-caprolactone) (PCL) microspheres were fabricated via a "Pickering-type" emulsion solvent evaporation method in the absence of any molecular surfactants. It was clarified that the interaction between carbonyl/carboxylic acid groups of PCL and the HAp nanoparticles at an oil-water interface played a crucial role in the preparation of the stable Pickering-type emulsions and the HAp nanoparticle-armored microspheres. The HAp nanoparticle-armored PCL microspheres were characterized in terms of size, size distribution, morphology, and chemical compositions using scanning electron microscopy, laser diffraction, energy dispersive X-ray microanalysis, and thermogravimetric analysis. The presence of HAp nanoparticles at the surface of the microspheres was confirmed by scanning electron microscopy and energy dispersive X-ray microanalysis. Pyrolysis of the PCL cores led to the formation of the corresponding HAp hollow microcapsules. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Novel synthesis strategy for composite hydrogel of collagen/hydroxyapatite-microsphere originating from conversion of CaCO3 templates.

    PubMed

    Wei, Qingrong; Lu, Jian; Wang, Qiaoying; Fan, Hongsong; Zhang, Xingdong

    2015-03-20

    Inspired by coralline-derived hydroxyapatite, we designed a methodological route to synthesize carbonated-hydroxyapatite microspheres from the conversion of CaCO3 spherulite templates within a collagen matrix under mild conditions and thus constructed the composite hydrogel of collagen/hydroxyapatite-microspheres. Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) were employed to confirm the successful generation of the carbonated hydroxyapatite phase originating from CaCO3, and the ratios of calcium to phosphate were tracked over time. Variations in the weight portion of the components in the hybrid gels before and after the phase transformation of the CaCO3 templates were identified via thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) shows these composite hydrogels have a unique multiscale microstructure consisting of a collagen nanofibril network and hydroxyapatite microspheres. The relationship between the hydroxyapatite nanocrystals and the collagen fibrils was revealed by transmission electron microscopy (TEM) in detail, and the selected area electron diffraction (SAED) pattern further confirmed the results of the XRD analyses which show the typical low crystallinity of the generated hydroxyapatite. This smart synthesis strategy achieved the simultaneous construction of microscale hydroxyapatite particles and collagen fibrillar hydrogel, and appears to provide a novel route to explore an advanced functional hydrogel materials with promising potentials for applications in bone tissue engineering and reconstruction medicine.

  12. Chlorhexidine-loaded hydroxyapatite microspheres as an antimicrobial delivery system and its effect on in vivo osteo-conductive properties.

    PubMed

    Soriano-Souza, Carlos Alberto; Rossi, Andre L; Mavropoulos, Elena; Hausen, Moema A; Tanaka, Marcelo N; Calasans-Maia, Mônica D; Granjeiro, Jose M; Rocha-Leão, Maria Helena M; Rossi, Alexandre M

    2015-04-01

    Hydroxyapatite (HA) has been investigated as a delivery system for antimicrobial and antibacterial agents to simultaneously stimulate bone regeneration and prevent infection. Despite evidence supporting the bactericidal efficiency of these HA carriers, few studies have focused on the effect of this association on bone regeneration. In this work, we evaluated the physico-chemical properties of hydroxyapatite microspheres loaded with chlorhexidine (CHX) at two different concentrations, 0.9 and 9.1 μgCHX/cm2 HA, and characterized their effects on in vitro osteoblast viability and bone regeneration. Ultraviolet-visible spectroscopy, scanning and transmission electron microscopy associated with energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy were used to characterize the association of CHX and HA nanoparticles. The high CHX loading dose induced formation of organic CHX plate-like aggregates on the HA surface, whereas a Langmuir film was formed at the low CHX surface concentration. Quantitative evaluation of murine osteoblast viability parameters, including adhesion, mitochondrial activity and membrane integrity of cells exposed to HA/CHX extracts, revealed a cytotoxic effect for both loading concentrations. Histomorphological analysis upon implantation into the dorsal connective tissues and calvaria of rats for 7 and 42 days showed that the high CHX concentration induced the infiltration of inflammatory cells, resulting in retarded bone growth. Despite a strong decrease in in vitro cell viability, the low CHX loading dose did not impair the biocompatibility and osteoconductivity of HA during bone repair. These results indicate that high antimicrobial doses may activate a strong local inflammatory response and disrupt the long-term osteoconductive properties of CHX-HA delivery systems.

  13. Polyphosphazene/Nano-Hydroxyapatite Composite Microsphere Scaffolds for Bone Tissue Engineering

    PubMed Central

    Nukavarapu, Syam P.; Kumbar, Sangamesh G.; Brown, Justin L.; Krogman, Nicholas R.; Weikel, Arlin L.; Hindenlang, Mark D.; Nair, Lakshmi S.; Allcock, Harry R; Laurencin, Cato T.

    2009-01-01

    The non-toxic, neutral degradation products of amino acid ester polyphosphazenes make them ideal candidates for in vivo orthopaedic applications. The quest for new osteocompatible materials for load bearing tissue engineering applications has led us to investigate mechanically competent amino acid ester substituted polyphosphazenes. In this study, we have synthesized three biodegradable polyphosphazenes substituted with side groups namely leucine, valine and phenylalanine ethyl esters. Of these polymers, the phenylalanine ethyl ester substituted polyphosphazene showed the highest glass transition temperature (41.6 °C) and hence was chosen as a candidate material for forming composite microspheres with 100 nm sized hydroxyapatite (nHAp). The fabricated composite microspheres were sintered into a three-dimensional (3-D) porous scaffold by adopting a dynamic solvent sintering approach. The composite microsphere scaffolds showed compressive moduli of 46–81 MPa with mean pore diameters in the range of 86–145 µm. The three-dimensional polyphosphazene-nHAp composite microsphere scaffolds showed good osteoblast cell adhesion, proliferation and alkaline phosphatase expression, and are potential suitors for bone tissue engineering applications. PMID:18517248

  14. Fabrication, characterization, and in vitro evaluation of poly(lactic acid glycolic acid)/nano-hydroxyapatite composite microsphere-based scaffolds for bone tissue engineering in rotating bioreactors.

    PubMed

    Lv, Qing; Nair, Lakshmi; Laurencin, Cato T

    2009-12-01

    Dynamic flow culture bioreactor systems have been shown to enhance in vitro bone tissue formation by facilitating mass transfer and providing mechanical stimulation. Our laboratory has developed a biodegradable poly (lactic acid glycolic acid) (PLAGA) mixed scaffold consisting of lighter-than-water (LTW) and heavier-than-water (HTW) microspheres as potential matrices for engineering tissue using a high aspect ratio vessel (HARV) rotating bioreactor system. We have demonstrated enhanced osteoblast differentiation and mineralization on PLAGA scaffolds in the HARV rotating bioreactor system when compared with static culture. The objective of the present study is to improve the mechanical properties and bioactivity of polymeric scaffolds by designing LTW polymer/ceramic composite scaffolds suitable for dynamic culture using a HARV bioreactor. We employed a microsphere sintering method to fabricate three-dimensional PLAGA/nano-hydroxyapatite (n-HA) mixed scaffolds composed of LTW and HTW composite microspheres. The mechanical properties, pore size and porosity of the composite scaffolds were controlled by varying parameters, such as sintering temperature, sintering time, and PLAGA/n-HA ratio. The PLAGA/n-HA (4:1) scaffold sintered at 90 degrees C for 3 h demonstrated the highest mechanical properties and an appropriate pore structure for bone tissue engineering applications. Furthermore, evaluation human mesenchymal stem cells (HMSCs) response to PLAGA/n-HA scaffolds was performed. HMSCs on PLAGA/n-HA scaffolds demonstrated enhanced proliferation, differentiation, and mineralization when compared with those on PLAGA scaffolds. Therefore, PLAGA/n-HA mixed scaffolds are promising candidates for HARV bioreactor-based bone tissue engineering applications. Copyright 2008 Wiley Periodicals, Inc.

  15. Preparation of chitosan/nano hydroxyapatite organic-inorganic hybrid microspheres for bone repair.

    PubMed

    Chen, Jingdi; Pan, Panpan; Zhang, Yujue; Zhong, Shengnan; Zhang, Qiqing

    2015-10-01

    In this work, we encapsulated icariin (ICA) into chitosan (CS)/nano hydroxyapatite (nHAP) composite microspheres to form organic-inorganic hybrid microspheres for drug delivery carrier. The composition and morphology of composite microspheres were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry- thermogravimetric analysis (DSC-TGA). Moreover, we further studied the performance of swelling properties, degradation properties and drug release behavior of the microspheres. ICA, the extract of traditional Chinese medicine-epimedium, was combined to study drug release properties of the microspheres. ICA loaded microspheres take on a sustained release behavior, which can be not only ascribed to electrostatic interaction between reactive negative hydroxyl (OH) of ICA and positive amine groups (NH₂) of CS, but also depended on the homogeneous dispersion of HAP nanoparticles inside CS organic matrix. In addition, the adhesion and morphology of osteoblasts were detected by inverted fluorescence microscopy. The biocompatibility of CS/nHAP/ICA microspheres was evaluated by the MTT cytotoxicity assay, Hoechst 33258 and PI fluorescence staining. These studies demonstrate that composite microspheres provide a suitable microenvironment for osteoblast attachment and proliferation. It can be speculated that the ICA loaded CS-based organic-inorganic hybrid microspheres might have potential applications in drug delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Characterization of polymeric solutions as injectable vehicles for hydroxyapatite microspheres.

    PubMed

    Oliveira, Serafim M; Almeida, Isabel F; Costa, Paulo C; Barrias, Cristina C; Ferreira, M Rosa Pena; Bahia, M Fernanda; Barbosa, Mário A

    2010-06-01

    A polymeric solution and a reinforcement phase can work as an injectable material to fill up bone defects. However, the properties of the solution should be suitable to enable the transport of that extra phase. Additionally, the use of biocompatible materials is a requirement for tissue regeneration. Thus, we intended to optimize a biocompatible polymeric solution able to carry hydroxyapatite microspheres into bone defects using an orthopedic injectable device. To achieve that goal, polymers usually regarded as biocompatible were selected, namely sodium carboxymethylcellulose, hydroxypropylmethylcellulose, and Na-alginate (ALG). The rheological properties of the polymeric solutions at different concentrations were assessed by viscosimetry before and after moist heat sterilization. In order to correlate rheological properties with injectability, solutions were tested using an orthopedic device applied for minimal invasive surgeries. Among the three polymers, ALG solutions presented the most suitable properties for our goal and a non-sterile ALG 6% solution was successfully used to perform preliminary injection tests of hydroxyapatite microspheres. Sterile ALG 7.25% solution was found to closely match non-sterile ALG 6% properties and it was selected as the optimal vehicle. Finally, sterile ALG 7.25% physical stability was studied at different temperatures over a 3-month period. It was observed that its rheological properties presented minor changes when stored at 25 degrees C or at 4 degrees C.

  17. Sustained release of simvastatin from hollow carbonated hydroxyapatite microspheres prepared by aspartic acid and sodium dodecyl sulfate.

    PubMed

    Wang, Ke; Wang, Yinjing; Zhao, Xu; Li, Yi; Yang, Tao; Zhang, Xue; Wu, Xiaoguang

    2017-06-01

    Hollow carbonated hydroxyapatite (HCHAp) microspheres as simvastatin (SV) sustained-release vehicles were fabricated through a novel and simple one-step biomimetic strategy. Firstly, hollow CaCO 3 microspheres were precipitated through the reaction of CaCl 2 with Na 2 CO 3 in the presence of aspartic acid and sodium dodecyl sulfate. Then, the as-prepared hollow CaCO 3 microspheres were transformed into HCHAp microspheres with a controlled anion-exchange method. The HCHAp microspheres were 3-5μm with a shell thickness of 0.5-1μm and were constructed of short needle nanoparticles. The HCHAp microspheres were then loaded with SV, exhibiting excellent drug-loading capacity and sustained release properties. These results present a new material synthesis strategy for HCHAp microspheres and suggest that the as-prepared HCHAp microspheres are promising for applications in drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. In Vivo Osteogenic Potential of Biomimetic Hydroxyapatite/Collagen Microspheres: Comparison with Injectable Cement Pastes

    PubMed Central

    Manzanares, Maria-Cristina; Ginebra, Maria-Pau; Franch, Jordi

    2015-01-01

    The osteogenic capacity of biomimetic calcium deficient hydroxyapatite microspheres with and without collagen obtained by emulsification of a calcium phosphate cement paste has been evaluated in an in vivo model, and compared with an injectable calcium phosphate cement with the same composition. The materials were implanted into a 5 mm defect in the femur condyle of rabbits, and bone formation was assessed after 1 and 3 months. The histological analysis revealed that the cements presented cellular activity only in the margins of the material, whereas each one of the individual microspheres was covered with osteogenic cells. Consequently, bone ingrowth was enhanced by the microspheres, with a tenfold increase compared to the cement, which was associated to the higher accessibility for the cells provided by the macroporous network between the microspheres, and the larger surface area available for osteoconduction. No significant differences were found in terms of bone formation associated with the presence of collagen in the materials, although a more extensive erosion of the collagen-containing microspheres was observed. PMID:26132468

  19. Microsphere-Based Scaffolds Encapsulating Tricalcium Phosphate And Hydroxyapatite For Bone Regeneration

    PubMed Central

    Gupta, Vineet; Lyne, Dina V.; Barragan, Marilyn; Berkland, Cory J.; Detamore, Michael S.

    2016-01-01

    Bioceramic mixtures of tricalcium phosphate (TCP) and hydroxyapatite (HAp) are widely used for bone regeneration because of their excellent cytocompatibility, osteoconduction, and osteoinduction. Therefore, we hypothesized that incorporation of a mixture of TCP and HAp in microsphere-based scaffolds would enhance osteogenesis of rat bone marrow stromal cells (rBMSCs) compared to a positive control of scaffolds with encapsulated bone-morphogenic protein-2 (BMP-2). Poly(D,L-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds encapsulating TCP and HAp mixtures in two different ratios (7:3 and 1:1) were fabricated with the same net ceramic content (30 wt%) to evaluate how incorporation of these ceramic mixtures would affect the osteogenesis in rBMSCs. Encapsulation of TCP/HAp mixtures impacted microsphere morphologies and the compressive moduli of the scaffolds. Additionally, TCP/HAp mixtures enhanced the end-point secretion of extracellular matrix (ECM) components relevant to bone tissue compared to the “blank” (PLGA-only) microsphere-based scaffolds as evidenced by the biochemical, gene expression, histology, and immunohistochemical characterization. Moreover, the TCP/HAp mixture groups even surpassed the BMP-2 positive control group in some instances in terms of matrix synthesis and gene expression. Lastly, gene expression data suggested that the rBMSCs responded differently to different TCP/HAp ratios presented to them. Altogether, it can be concluded that TCP/HAp mixtures stimulated the differentiation of rBMSCs toward an osteoblastic phenotype, and therefore may be beneficial in gradient microsphere-based scaffolds for osteochondral regeneration. PMID:27272903

  20. Physicochemical and mechanical properties of freeze cast hydroxyapatite-gelatin scaffolds with dexamethasone loaded PLGA microspheres for hard tissue engineering applications.

    PubMed

    Ghorbani, Farnaz; Nojehdehian, Hanieh; Zamanian, Ali

    2016-12-01

    Hydroxyapatite (HA)-gelatin scaffolds incorporated with dexamethasone-loaded polylactic-co-glycolic acid (PLGA) microspheres were synthesized by freeze casting technique. Scanning electron microscopy (SEM) micrographs demonstrated a unidirectional microstructure and a decrease in the pore size as a function of temperature gradient. Higher amounts of HA resulted in a decrease in the pore size. According to the results, at lower cooling rates, the formation of a lamellar structure decreased the mechanical strength, but at the same time, enhanced the swelling ratio, biodegradation rate and drug release level. On the other hand, higher weight ratios of HA increased the compressive strength, and reduced the swelling ratio, biodegradation rate and drug release level. The results obtained by furrier transform infrared spectroscopy (FTIR) and bioactivity analysis illustrated that the interactions of the materials support the apatite formation in the simulated body fluid (SBF) solution. Based on the obtained results, the synthesized composite scaffolds have the necessary mechanical and physicochemical features to support the regeneration of defects and to maintain their stability during the neo-tissue formation. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Biopolymers for Medical Applications: Polyglycerol Sebacate (PGS) doped Hydroxyapatite (HA)

    NASA Astrophysics Data System (ADS)

    Teruel, Maria; Kuthirummal, Narayanan; Levi, Nicole; Wake College Team

    2011-04-01

    In the investigation to engineer the ideal scaffolding device for cleft palate repair, polyglycerol sebacate (PGS) doped with hydroxyapatite (HA) were chosen for their elastomeric and biodegradable properties, as well as their cost-effective synthesis. Hydroxyapatite was integrated into the PGS to form a composite with high porosity and improved mechanical properties yielding a good substrate for cell attachment during the repair process. FT-IR scans were performed to characterize the composite polymer. Differential Scanning Calorimetry (DSC) was utilized to identify an acceptable glass transition temperature (Tg), between -18 and - 21°C. At this Tg, it was determined that the material was sufficiently polymerized to a point where it was durable yet pliable enough to use for cleft palate devices. In the synthesis of PGS 3% and 5% HA, a Tg of - 20.10°C and - 21.72°C, respectively, was achieved and further analytical tests were then performed on the polymers. Methods of analysis included X-Ray Diffraction and Tensile Strength Testing. Acknowledgements to the Research Department of Plastic and Reconstructive Surgery, Wake Forest University and College of Charleston.

  2. [Construction of porous hydroxyapatite (HA) block loaded with cultured chondrocytes].

    PubMed

    Yan, M; Dang, G

    1999-07-01

    To construct a kind of bone healing enhancing implant with cultured chondrocytes bound to hydroxyapatite (HA). Chondrocytes were obtained from the costicartilage of rat and were cultured on the porous HA blocks, 3 mm x 3 mm x 4 mm size, for three and seven days. Scanning electron micrograph was taken to show whether the cells grew outside and inside the pore of HA block. The cells cultured on tiny glass sheet for 2 days were used to prove where the cells come from by in situ hybridization technique with alpha1 (II) cDNA probe. Scanning electron micrographs showed that the pores of the HA surface and inside of the blocks are filled with cultured cells, especially the longer cultured block. The cells were chondrocytes confirmed by in situ hybridization. The porous HA can be used as cell cultured substrate and chondrocyte can adhere and proliferate inside the porous HA block.

  3. Mechanical properties of titanium-hydroxyapatite (Ti-HA) composite coating on stainless steel prepared by thermal spraying

    NASA Astrophysics Data System (ADS)

    Rosmamuhamadani, R.; Azhar, N. H.; Talari, M. K.; Yahaya, Sabrina M.; Sulaiman, S.; Ismail, M. I. S.

    2017-09-01

    Addition of hydroxyapatite (HA) can enhance the bioactivity of the common metallic implant due to its similarity with natural bones and teeth. In this investigation, high velocity oxy-fuel (HVOFT) technique was used to deposit titanium-hydroxyapatite (Ti-HA) composite on stainless steel substrate plate with different percentage of HA for biomedical applications. The aim of this research is to investigate the mechanical properties of Ti-HA coating such as hardness, adhesion strength and wear behaviour. The hardness and strength was determined by using SHIMADZU-microhardness Vickers tester and PosiTest AT portable adhesion tester respectively. The wear test was performed by using pin-on-disk equipment and field emission scanning electron microscope (FESEM) used to determine the extent of surface damage. From the results obtained, mechanical properties such as hardness and adhesion strength of titanium (Ti) coating decreased with the increased of HA contents. Meanwhile, the coefficient of friction of Ti-10% HA coating shows the highest value compare to others as three-body abrasion had occurred during the test.

  4. Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

    PubMed Central

    CALASANS-MAIA, Mônica Diuana; de MELO, Bruno Raposo; ALVES, Adriana Terezinha Neves Novellino; RESENDE, Rodrigo Figueiredo de Brito; LOURO, Rafael Seabra; SARTORETTO, Suelen Cristina; GRANJEIRO, José Mauro; ALVES, Gutemberg Gomes

    2015-01-01

    ABSTRACT Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA). Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day. Conclusion CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption. PMID:26814461

  5. Long-term conversion of 45S5 bioactive glass-ceramic microspheres in aqueous phosphate solution.

    PubMed

    Fu, Hailuo; Rahaman, Mohamed N; Day, Delbert E; Huang, Wenhai

    2012-05-01

    The conversion of 45S5 glass and glass-ceramics to a hydroxyapatite (HA)-like material in vitro has been studied extensively, but only for short reaction times (typically <3 months). In this paper, we report for the first time on the long-term conversion of 45S5 glass-ceramic microspheres (designated 45S5c) in an aqueous phosphate solution. Microspheres of 45S5c (75-150 μm) were immersed for 10 years at room temperature (~25 °C) in K(2)HPO(4) solution with a concentration of 0.01 M or 1.0 M, and with a starting pH of 7.0 or 9.5. The reacted 45S5c microspheres and solutions were analyzed using structural and analytical techniques. Only 25-45 vol% of the 45S5c microspheres were converted to an HA-like material after the 10 year reaction. In solutions with a starting pH of 9.5, an increase in the K(2)HPO(4) concentration from 0.01 to 1.0 M resulted in a doubling of the volume of the microspheres converted to an HA-like material but had little effect on the composition of the HA-like product. In comparison, reaction of the 45S5c microspheres in the solution with a starting pH of 7.0 resulted in an HA-like product in the 0.01 M K(2)HPO(4) solution but a calcium pyrophosphate product, Ca(10)K(4)(P(2)O(7))(6).9H(2)O, in the 1.0 M solution. The consequences of these results for the long-term use of 45S5 glass-ceramics in biomedical applications are discussed.

  6. The Evaluation of Hydroxyapatite (HA) Coated and Uncoated Porous Tantalum for Biomedical Material Applications

    NASA Astrophysics Data System (ADS)

    Safuan, Nadia; Sukmana, Irza; Kadir, Mohammed Rafiq Abdul; Noviana, Deni

    2014-04-01

    Porous tantalum has been used as an orthopedic implant for bone defects as it has a good corrosion resistance and fatigue behaviour properties. However, there are some reports on the rejection of porous Ta after the implantation. Those clinical cases refer to the less bioactivity of metallic-based materials. This study aims to evaluate hydroxyapatite coated and uncoated porous Tantalum in order to improve the biocompatibility of porous tantalum implant and osseointegration. Porous tantalum was used as metallic-base substrate and hydroxyapatite coating has been done using plasma-spraying technique. Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) techniques were utilizes to investigate the coating characteristics while Confocal Raman Microscopy to investigate the interface and image. The effect of coating to the corrosion behaviour was assessed by employing potentiodynamic polarization tests in simulated body fluid at 37±1 °C. Based on SEM and FESEM results, the morphologies as well the weight element consists in the uncoated and hydroxyapatite coated porous tantalum were revealed. The results indicated that the decrease in corrosion current density for HA coated porous Ta compared to the uncoated porous Ta. This study concluded that by coating porous tantalum with HA supports to decrease the corrosion rate of pure porous.

  7. [Study on biocompatibility of hydroxyapatite/high density polyethylene (HA/HDPE) nano-composites artificial ossicle].

    PubMed

    Wang, Guohui; Zhu, Shaihong; Tan, Guolin; Zhou, Kechao; Huang, Suping; Zhao, Yanzhong; Li, Zhiyou; Huang, Boyun

    2008-06-01

    This study was aimed to evaluate the biocompatibility of Hydroxyapatite/High density polyethylene (HA/ HDPE) nano-composites artificial ossicle. The percentage of S-period cells were detected by flow cytometry after L929 cells being incubated with extraction of the HA/HDPE nano-composites; the titanium materials for clinical application served as the contrast. In addition, both materials were implanted in animals and the histopathological evaluations were conducted. There were no statistically significant differences between the two groups (P >0.05). The results demonstrated that the HA/HDPE nano-composite artificial ossicle made by our laboratory is of a good biocompatibility and clinical application outlook.

  8. Antibacterial activation of hydroxyapatite (HA) with controlled porosity by different antibiotics.

    PubMed

    Chai, F; Hornez, J-C; Blanchemain, N; Neut, C; Descamps, M; Hildebrand, H F

    2007-11-01

    In order to prevent the increasing frequency of per-operative infections, bioceramics can be loaded with anti-bacterial agents, which will release with respect to their chemical characteristics. A novel hydroxyapatite (HA) was elaborated with specific internal porosities for using as a bone-bioactive antibiotic (ATB) carrier material. UV spectrophotometry and bacteria inhibition tests were performed for testing the ATB adsorption and the microbiological effectiveness after loading with different antibiotics. The impregnation time, ATB impregnating concentration, impregnation condition and other factors, which might influence the ATB loading effect, were studied by exposure to different releasing solvents and different pathogenic bacteria: Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. It clearly showed that the facility of ATB loading on this porous HA is even possible just under simple non-vacuum impregnation conditions in a not-so-long impregnating interval. The results also showed that, for all three types of ATB (vancomycin, ciprofloxacin and gentamicin), adsorbed amount on the micro-porous HA were hugely higher than that on dense HA. The micro-porosity of test HA had also significantly prolonged the release time of antibiotics even under mimic physiological conditions. Furthermore, it also has primarily proved by a pilot test that the antibacterial efficiency of crude micro-porous HA could be further significantly improved by other methods of functionalization such as cold plasma technique.

  9. Effect of molecular weight of hyaluronic acid (HA) on viscoelasticity and particle texturing feel of HA dermal biphasic fillers.

    PubMed

    Chun, Cheolbyong; Lee, Deuk Yong; Kim, Jin-Tae; Kwon, Mi-Kyung; Kim, Young-Zu; Kim, Seok-Soon

    2016-01-01

    Hyaluronic acid (HA) dermal biphasic fillers are synthesized for their efficacy in correcting aesthetic defects such as wrinkles, scars and facial contouring defects. The fillers consist of crosslinked HA microspheres suspended in a noncrosslinked HA. To extend the duration of HAs within the dermis and obtain the particle texturing feel, HAs are crosslinked to obtain the suitable mechanical properties. Hyaluronic acid (HA) dermal biphasic fillers are prepared by mixing the crosslinked HA microspheres and the noncrosslinked HAs. The elastic modulus of the fillers increased with raising the volume fraction of the microspheres. The mechanical properties and the particle texturing feel of the fillers made from crosslinked HA (1058 kDa) microspheres suspended in noncrosslinked HA (1368 kDa) are successfully achieved, which are adequate for the fillers. Dermal biphasic HA fillers made from 1058 kDa exhibit suitable elastic moduli (211 to 420 Pa) and particle texturing feel (scale 7 ~ 9).

  10. Wear characterization of nano-hydroxyapatite with addition of titanium (HA-Ti)

    NASA Astrophysics Data System (ADS)

    Rosmamuhamadani, R.; Arawi, A. Z. O.; Talari, M. K.; Mahat, M. M.; Bonnia, N. N.; Sabrina; Yahaya, M.; Sulaiman, S.; Ismail, M. I. S.

    2018-04-01

    Hydroxyapatite (Ca10 (PO4)6(OH)2, HA), is an attractive material of an inorganic compound whose chemical composition and crystallographic structures are similar to the composition of the bone. A natural source such as egg shells is composed of 94 wt. % of calcium carbonate (CaCO3), which can be calcined as calcium oxide (CaO) by the calcinations process. The efficient temperature to produce CaO is 900 °C for 2 hours. The synthesis of nano-HA was done by the mixing the diammonium phosphate (DAP) and calcium hydroxide (Ca(OH)2) and subjected into a microwave for 30 minutes at 1100 W irradiation power. Ball milling process was used for 30 minutes to mix the nano-HA with different compositions of titanium. These were pressed to form pallets by hand hydraulic pump (force=2300 psi). The pallets then were sintered at 1200 °C with the heating rate of 3 °C/min for 2 hours. The pallets were tested by several mechanical testing including hardness, compression strength and wear. From the results, HA-25wt. %Ti composite gave the highest hardness, compression and coefficient of friction for wear test values which were 89.6 Hv, 82.5MPa and 0.76μ respectively. It showed that by adding Ti to nano-HA, the mechanical properties of nano-HA could be enhanced. The microstructure analyses by optical micrograph showed that nano-HA-Ti particles displayed shape likes needle morphology. The particles showed the high tendency to form the agglomerations.

  11. Silicon-hydroxyapatite bioactive coatings (Si-HA) from diatomaceous earth and silica. Study of adhesion and proliferation of osteoblast-like cells.

    PubMed

    López-Alvarez, M; Solla, E L; González, P; Serra, J; León, B; Marques, A P; Reis, R L

    2009-05-01

    The aim of this study consisted on investigating the influence of silicon substituted hydroxyapatite (Si-HA) coatings over the human osteoblast-like cell line (SaOS-2) behaviour. Diatomaceous earth and silica, together with commercial hydroxyapatite were respectively the silicon and HA sources used to produce the Si-HA coatings. HA coatings with 0 wt% of silicon were used as control of the experiment. Pulsed laser deposition (PLD) was the selected technique to deposit the coatings. The Si-HA thin films were characterized by Fourier Transformed Infrared Spectroscopy (FTIR) demonstrating the efficient transfer of Si to the HA structure. The in vitro cell culture was established to assess the cell attachment, proliferation and osteoblastic activity respectively by, Scanning Electron Microscopy (SEM), DNA and alkaline phosphatase (ALP) quantification. The SEM analysis demonstrated a similar adhesion behaviour of the cells on the tested materials and the maintenance of the typical osteoblastic morphology along the time of culture. The Si-HA coatings did not evidence any type of cytotoxic behaviour when compared with HA coatings. Moreover, both the proliferation rate and osteoblastic activity results showed a slightly better performance on the Si-HA coatings from diatoms than on the Si-HA from silica.

  12. [Preparation of elastic porous cell scaffold fabricated with combined polydimethylsiloxane (PDMS) and hydroxyapatite (HA)].

    PubMed

    Yang, Yang; Lan, Ding; Huang, Yan; Li, Yanming; Wang, Yuren; Sun, Lianwen; Fan, Yubo

    2014-06-01

    Polydimethylsiloxane (PDMS) and hydroxyapatite (HA) were combined in our laboratory to fabricate an elastic porous cell scaffold with pore-forming agent, and then the scaffold was used as culture media for rat bone marrow derived mesenchymal stem cells (rBMSCs). Different porous materials (square and circular in shape) were prepared by different pore-forming agents (NaCl or paraffin spheres) with adjustable porosity (62%-76%). The HA crystals grew on the wall of hole when the material was exposed to SBF solutions, showing its biocompatibility and ability to support the cells to attach on the materials.

  13. [Cytocompatibility of nanophase hydroxyapatite ceramics].

    PubMed

    Wen, Bo; Chen, Zhi-qing; Jiang, Yin-shan; Yang, Zheng-wen; Xu, Yong-zhong

    2004-12-01

    To evaluate the cytocompatibility of nanophase hydroxyapatite ceramics in vitro. Hydroxyapatite (HA) was prepared via wet method. The grain size of the hydroxyapatite in the study was determined by scanning electron microscope and atomic force microscope with image analysis software. Primary osteoblast culture was established from rat calvaria. Cell adherence and proliferation on nanophase hydroxyapatite ceramics and conventional hydroxyapatite ceramics were examined at 1, 3, 5, 7 days. Morphology of the cells was observed by microscope. The average grain size of the nanophase and conventional HA was 55 nm and 780 nm, respectively. Throughout 7 days period, osteoblast proliferation on the HA was similar to that on tissue culture borosilicate glass controls, osteoblasts could attach, spread and proliferate on HA. However, compared to conventional ceramics, osteoblast proliferation on nanophase HA was significantly better after 1, 3, 5 and 7 days. Cytocompatibility of nanophase HA was significantly better than conventional ceramics.

  14. Hydroxyapatite hierarchically nanostructured porous hollow microspheres: rapid, sustainable microwave-hydrothermal synthesis by using creatine phosphate as an organic phosphorus source and application in drug delivery and protein adsorption.

    PubMed

    Qi, Chao; Zhu, Ying-Jie; Lu, Bing-Qiang; Zhao, Xin-Yu; Zhao, Jing; Chen, Feng; Wu, Jin

    2013-04-22

    Hierarchically nanostructured porous hollow microspheres of hydroxyapatite (HAP) are a promising biomaterial, owing to their excellent biocompatibility and porous hollow structure. Traditionally, synthetic hydroxyapatite is prepared by using an inorganic phosphorus source. Herein, we report a new strategy for the rapid, sustainable synthesis of HAP hierarchically nanostructured porous hollow microspheres by using creatine phosphate disodium salt as an organic phosphorus source in aqueous solution through a microwave-assisted hydrothermal method. The as-obtained products are characterized by powder X-ray diffraction (XRD), Fourier-transform IR (FTIR) spectroscopy, SEM, TEM, Brunauer-Emmett-Teller (BET) nitrogen sorptometry, dynamic light scattering (DLS), and thermogravimetric analysis (TGA). SEM and TEM micrographs show that HAP hierarchically nanostructured porous hollow microspheres consist of HAP nanosheets or nanorods as the building blocks and DLS measurements show that the diameters of HAP hollow microspheres are within the range 0.8-1.5 μm. The specific surface area and average pore size of the HAP porous hollow microspheres are 87.3 m(2) g(-1) and 20.6 nm, respectively. The important role of creatine phosphate disodium salt and the influence of the experimental conditions on the products were systematically investigated. This method is facile, rapid, surfactant-free and environmentally friendly. The as-prepared HAP porous hollow microspheres show a relatively high drug-loading capacity and protein-adsorption ability, as well as sustained drug and protein release, by using ibuprofen as a model drug and hemoglobin (Hb) as a model protein, respectively. These experiments indicate that the as-prepared HAP porous hollow microspheres are promising for applications in biomedical fields, such as drug delivery and protein adsorption. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Response of Human Osteoblast to n-HA/PEEK—Quantitative Proteomic Study of Bio-effects of Nano-Hydroxyapatite Composite

    NASA Astrophysics Data System (ADS)

    Zhao, Minzhi; Li, Haiyun; Liu, Xiaochen; Wei, Jie; Ji, Jianguo; Yang, Shu; Hu, Zhiyuan; Wei, Shicheng

    2016-03-01

    Nano-sized hydroxyapatite (n-HA) is considered as a bio-active material, which is often mixed into bone implant material, polyetheretherketone (PEEK). To reveal the global protein expression modulations of osteoblast in response to direct contact with the PEEK composite containing high level (40%) nano-sized hydroxyapatite (n-HA/PEEK) and explain its comprehensive bio-effects, quantitative proteomic analysis was conducted on human osteoblast-like cells MG-63 cultured on n-HA/PEEK in comparison with pure PEEK. Results from quantitative proteomic analysis showed that the most enriched categories in the up-regulated proteins were related to calcium ion processes and associated functions while the most enriched categories in the down-regulated proteins were related to RNA process. This enhanced our understanding to the molecular mechanism of the promotion of the cell adhesion and differentiation with the inhibition of the cell proliferation on n-HA/PEEK composite. It also exhibited that although the calcium ion level of incubate environment hadn’t increased, merely the calcium fixed on the surface of material had influence to intracellular calcium related processes, which was also reflect by the higher intracellular Ca2+ concentration of n-HA/PEEK. This study could lead to more comprehensive cognition to the versatile biocompatibility of composite materials. It further proves that proteomics is useful in new bio-effect discovery.

  16. Response of Human Osteoblast to n-HA/PEEK--Quantitative Proteomic Study of Bio-effects of Nano-Hydroxyapatite Composite.

    PubMed

    Zhao, Minzhi; Li, Haiyun; Liu, Xiaochen; Wei, Jie; Ji, Jianguo; Yang, Shu; Hu, Zhiyuan; Wei, Shicheng

    2016-03-09

    Nano-sized hydroxyapatite (n-HA) is considered as a bio-active material, which is often mixed into bone implant material, polyetheretherketone (PEEK). To reveal the global protein expression modulations of osteoblast in response to direct contact with the PEEK composite containing high level (40%) nano-sized hydroxyapatite (n-HA/PEEK) and explain its comprehensive bio-effects, quantitative proteomic analysis was conducted on human osteoblast-like cells MG-63 cultured on n-HA/PEEK in comparison with pure PEEK. Results from quantitative proteomic analysis showed that the most enriched categories in the up-regulated proteins were related to calcium ion processes and associated functions while the most enriched categories in the down-regulated proteins were related to RNA process. This enhanced our understanding to the molecular mechanism of the promotion of the cell adhesion and differentiation with the inhibition of the cell proliferation on n-HA/PEEK composite. It also exhibited that although the calcium ion level of incubate environment hadn't increased, merely the calcium fixed on the surface of material had influence to intracellular calcium related processes, which was also reflect by the higher intracellular Ca(2+) concentration of n-HA/PEEK. This study could lead to more comprehensive cognition to the versatile biocompatibility of composite materials. It further proves that proteomics is useful in new bio-effect discovery.

  17. Facile and controllable synthesis of hydroxyapatite/graphene hybrid materials with enhanced sensing performance towards ammonia.

    PubMed

    Zhang, Qing; Liu, Yong; Zhang, Ying; Li, Huixia; Tan, Yanni; Luo, Lanlan; Duan, Junhao; Li, Kaiyang; Banks, Craig E

    2015-08-07

    In this work, needle-like and micro-spherical agglomerates of nanocrystalline hydroxyapatite (HA) were successfully assembled on the surface of graphene sheets with the aid of dopamine having two roles, as a template and a reductant for graphite oxide during the process of self-polymerization. The crystalline structure and micromorphology of HA can be conveniently regulated by controlling the mineralization route either with a precipitation (cHA/GR) or biomimetic methodology (bHA/GR). Both the composites exhibit improvements of ∼150% and ∼250% in sensitivity towards the sensing of ammonia at room temperature, compared with that of bare graphene. The combination of the multi-adsorption capability of HA and the electric conductivity of graphene is proposed to be the major reason for the observed enhancements. Gas sensing tests demonstrated that the HA/GR composites exhibit excellent selectivity, high sensitivity and repeatable stability towards the analytical sensing of ammonia.

  18. Hydroxyapatite nanorod and microsphere functionalized with bioactive lactoferrin as a new biomaterial for enhancement bone regeneration.

    PubMed

    Shi, Pujie; Wang, Qun; Yu, Cuiping; Fan, Fengjiao; Liu, Meng; Tu, Maolin; Lu, Weihong; Du, Ming

    2017-07-01

    Lactoferrin (LF) has been recently recognized as a promising new novel bone growth factor for the beneficial effects on bone cells and promotion of bone growth. Currently, it has been attracted wide attention in bone regeneration as functional food additives or a potential bioactive protein in bone tissue engineering. The present study investigated the possibility that hydroxyapatite (HAP) particles, a widely used bone substitute material for high biocompatibility and osteoconductivity, functionalized with lactoferrin as a composite material are applied to bone tissue engineering. Two kinds of hydroxyapatite samples with different sizes, including nanorods and microspheres particles, were functionalized with lactoferrin molecules, respectively. A detailed characterization of as-prepared HAP-LF complex is presented, combining thermal gravimetric analysis (TGA) and Fourier Transform Infrared Spectroscopy (FT-IR). Zeta potential and the analysis of electrostatic surface potential of lactoferrin were carried to reveal the mechanism of adsorption. The effects of HAP-LF complex on MC3T3-E1 osteoblast proliferation and morphology were systematically evaluated at different culture time. Interestingly, results showed that cell viability of HAP-LF group was significantly higher than HAP group indicating that the HAP-LF can improve the biocompatibility of HAP, which mainly originated from a combination of HAP-LF interaction. These results indicated that hydroxyapatite particles can work as a controlled releasing carrier of lactoferrin successfully, and lactoferrin showed better potentiality on using in the field of bone regeneration by coupling with hydroxyapatite. This study would provide a new biomaterial and might offer a new insight for enhancement of bone regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Employing the cyclophosphate to accelerate the degradation of nano-hydroxyapatite/poly(amino acid) (n-HA/PAA) composite materials.

    PubMed

    Jing, Linjing; Chen, Li; Peng, Haitao; Ji, Mizhi; Xiong, Yi; Lv, Guoyu

    2017-12-01

    Owing to the good degradability and biocompatibility of polyphosphoesters (PPEs), the aim of the current study was to investigate a novel degradable composite of nano-hydroxyapatite/poly(amino acid) (n-HA/PAA) with cyclophosphate (CPE) via in situ melting polymerization to improve the degradation of n-HA/PAA. The structure of each composite was characterized via Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The degradation properties were studied in terms of the weight loss and pH in a phosphate-buffered saline (PBS) solution, while the surface morphology was examined using a scanning electron microscope-energy dispersive spectrometer (SEM-EDS) after soaking the surface in simulated body fluid (SBF). The cell proliferation, cell adhesion, and alkaline phosphatase (ALP) activity were used for the analysis of cytocompatibility. The weight loss results showed that the n-HA/PAA composite was 9.98 wt%, weighed after soaking in the PBS solution for 12 weeks, whereas the nano-hydroxyapatite/polyphosphoester-amino acid (n-HA/PPE-AA) composite was 46.94 wt%. The pH of the composites was in a suitable range between 6.64 to 7.06 and finally stabilized at 7.39. The SEM and EDS results revealed the formation of an apatite-like layer on the surface of the n-HA/PPE-AA composites after soaking in SBF for one week. The cell counting Kit 8 (CCK-8) assay of the cell culture in the leaching liquid of the n-HA/PPE-AA composites exhibited non-cytotoxicity and high-proliferation, and the cell adhesion showed the well spreading and normal phenotype extension of the cells on the n-HA/PPE-AA composites surface. Concurrently, the co-culture results of the composites and cells confirmed that the n-HA/PPE-AA composites exhibited a higher ALP activity. In summary, the results demonstrated that the n-HA/PPE-AA composites had a controllable degradation property, good bioactivity, and cytocompatibility.

  20. Controlled, sustained release of proteins via an injectable, mineral-coated microsphere delivery vehicle

    NASA Astrophysics Data System (ADS)

    Franklin-Ford, Travelle

    Hydroxyapatite interfaces have demonstrated strong protein binding and protein selection from a passing solution and can serve as a biocompatible carrier for controlled protein delivery. Hydroxyapatite is a major component of long bones and tooth enamel and is the most stable of all calcium phosphate isoforms in aqueous solutions at physiologic pH, providing a sensitive chromatographic mechanism for separating proteins. Here we describe an approach to create a synthetic hydroxyapatite coating through a biomimetic, heterogeneous nucleation from a modified simulated body fluid--supersaturated with calcium and phosphate ions on the surface of injectable polymer microspheres. We are able to bind and release bioactive growth factors into a variety of in vitro and in vivo conditions, demonstrating the functionality and advantage of the biomaterial. Creating a hydroxyapatite layer on the Poly(D,L-lactide-co-glycolide) (PLG) microsphere surface, avails the microsphere interior for another application that will not compete with protein binding and release. Encapsulating an imaging agent within the aqueous phase of the emulsion provides a visual reference for the injectable therapy upon microsphere fabrication. Another advantage of this system is that the mineral coating and subsequent protein binding is not compromised by the encapsulated imaging agent. This dual function delivery vehicle is not only advantageous for spatial tracking therapeutic applications, but also determining the longevity of the delivery vehicle once injected. In the broader sense, providing a mechanism to image and track our temporally controlled, sustained delivery system gives more evidence to support the effects of released protein on in vivo responses (bioactivity) and locate microspheres within different biological systems.

  1. Amorphous hydroxyapatite-sintered polymeric scaffolds for bone tissue regeneration: physical characterization studies.

    PubMed

    Cushnie, Emily K; Khan, Yusuf M; Laurencin, Cato T

    2008-01-01

    Given the inherent shortcomings of autografts and allografts, donor-site morbidity and risk of disease transmission, respectively, alternatives to traditional bone grafting options are warranted. To this end, poly(lactide-co-glycolide) (PLAGA) and in situ-synthesized amorphous hydroxyapatite (HA) were used to construct three-dimensional microsphere-based composite scaffolds of varying HA content for bone regeneration. In the current study, the effect of adding amorphous HA to the PLAGA scaffolds on their physical characteristics and in vitro degradation mechanism was investigated. Porosimetry and uniaxial compression testing were used to analyze the internal structure and elastic modulus of the scaffolds, respectively. Additionally, gel permeation chromatography (GPC) was performed to assess the polymer molecular weight over the course of an 8-week degradation study. HA content (17% or 27%) of the composite scaffolds was found to increase scaffold pore volume from 33.86% for pure polymer scaffolds, to 40.49% or 46.29%, depending on the amount of incorporated HA. This increased pore volume provided the composite scaffolds with a greater surface area and a corresponding decrease in elastic modulus. Scaffold degradation studies conducted over 8 weeks showed PLAGA to degrade in a first-order mechanism, with the rate of polymer degradation for the 27% HA composite scaffold being significantly slower than that of the pure PLAGA scaffold (degradation constants of 0.0324 and 0.0232 week(-1), respectively). These results suggest that the addition of amorphous HA to PLAGA microspheres resulted in porous, bioactive scaffolds that offer potential as alternative bone grafting materials for the field of regenerative medicine. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.

  2. Sr-containing hydroxyapatite: morphologies of HA crystals and bioactivity on osteoblast cells.

    PubMed

    Aina, Valentina; Bergandi, Loredana; Lusvardi, Gigliola; Malavasi, Gianluca; Imrie, Flora E; Gibson, Iain R; Cerrato, Giuseppina; Ghigo, Dario

    2013-04-01

    A series of Sr-substituted hydroxyapatites (HA), of general formula Ca(10-x)Srx(PO4)6(OH)2, where x=2 and 4, were synthesized by solid state methods and characterized extensively. The reactivity of these materials in cell culture medium was evaluated, and the behavior towards MG-63 osteoblast cells (in terms of cytotoxicity and proliferation assays) was studied. Future in vivo studies will give further insights into the behavior of the materials. A paper by Lagergren et al. (1975), concerning Sr-substituted HA prepared by a solid state method, reports that the presence of Sr in the apatite composition strongly influences the apatite diffraction patterns. Zeglinsky et al. (2012) investigated Sr-substituted HA by ab initio methods and Rietveld analyses and reported changes in the HA unit cell volume and shape due to the Sr addition. To further clarify the role played by the addition of Sr on the physico-chemical properties of these materials we prepared Sr-substituted HA compositions by a solid state method, using different reagents, thermal treatments and a multi-technique approach. Our results indicated that the introduction of Sr at the levels considered here does influence the structure of HA. There is also evidence of a decrease in the crystallinity degree of the materials upon Sr addition. The introduction of increasing amounts of Sr into the HA composition causes a decrease in the specific surface area and an enrichment of Sr-apatite phase at the surface of the samples. Bioactivity tests show that the presence of Sr causes changes in particle size and/or morphology during soaking in MEM solution; on the contrary the morphology of pure HA does not change after 14 days of reaction. The presence of Sr, as Sr-substituted HA and SrCl2, in cultures of human MG-63 osteoblasts did not produce any cytotoxic effect. In fact, Sr-substituted HA increased the proliferation of osteoblast cells and enhanced cell differentiation: Sr in HA has a positive effect on MG-63 cells

  3. Degradation pattern of porous CaCO3 and hydroxyapatite microspheres in vitro and in vivo for potential application in bone tissue engineering.

    PubMed

    Zhong, Qiwei; Li, Wenhua; Su, Xiuping; Li, Geng; Zhou, Ying; Kundu, Subhas C; Yao, Juming; Cai, Yurong

    2016-07-01

    Despite superior clinical handling, excellent biocompatibility, biodegradation property of calcium phosphate needs to be improved to coincide with the rate of new bone formation. In this study, spherical CaCO3 are fabricated in the presence of the silk sericin and then transformed into porous hydroxyapatite (HAP) microspheres via hydrothermal method. The degradation behavior of obtained CaCO3, HAP and their mixture is first investigated in vitro. The result demonstrates that the weight loss of HAP microspheres are almost 24.3% after immersing in pH 7.40 Tris-HCl buffer solution for 12 weeks, which is far slower than that of spherical CaCO3 (97.5%). The degradation speed of the mixtures depends on the proportion of CaCO3 and HAP. The mixture with higher content of CaCO3 possesses a quicker degradation speed. The obtained CaCO3 and HAP microspheres are injected into subcutaneous tissue of ICR mice with the assistance of sodium alginate. The result in vivo also shows an obvious difference of degradation speed between the obtained CaCO3 and HAP microspheres, implying it is feasible to modulate the degradation property of the mixture through changing the proportion of CaCO3 and HAP The good cytocompatibility of the two kinds of microspheres is proved and a mild inflammation response is observed only at early stage of implantation. The job offers a simple method to modify the degradation properties of biomaterial for potential use in bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Nutrient-substituted hydroxyapatites: synthesis and characterization

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Ming, D. W.

    1999-01-01

    Incorporation of Mg, S, and plant-essential micronutrients into the structure of synthetic hydroxyapatite (HA) may be advantageous for closed-loop systems, such as will be required on Lunar and Martian outposts, because these apatites can be used as slow-release fertilizers. Our objective was to synthesize HA with Ca, P, Mg, S, Fe, Cu, Mn, Zn, Mo, B, and Cl incorporated into the structure, i.e., nutrient-substituted apatites. Hydroxyapatite, carbonate hydroxyapatite (CHA), nutrient-substituted hydroxyapatite (NHA), and nutrient-substituted carbonate hydroxyapatite (NCHA) were synthesized by precipitating from solution. Chemical and mineralogical analysis of precipitated samples indicated a considerable fraction of the added cations were incorporated into HA, without mineral impurities. Particle size of the HA was in the 1 to 40 nm range, and decreased with increased substitution of nutrient elements. The particle shape of HA was elongated in the c-direction in unsubstituted HA and NHA but more spherical in CHA and NCHA. The substitution of cations and anions in the HA structure was confirmed by the decrease of the d[002] spacing of HA with substitution of ions with an ionic radius less than that of Ca or P. The DTPA-extractable Cu ranged from 8 to 8429 mg kg-1, Zn ranged from 57 to 1279 mg kg-1, Fe from 211 to 2573 mg kg-1, and Mn from 190 to 1719 mg kg-1, depending on the substitution level of each element in HA. Nutrient-substituted HA has the potential to be used as a slow-release fertilizer to supply micronutrients, S, and Mg in addition to Ca and P.

  5. [Study on the antibacterial activity of four kinds of nano-hydroxyapatite composites against Enterococcus faecalis].

    PubMed

    Liu, Yi; Zhou, Rongjing; Wu, Hongkun

    2015-06-01

    This study aims to compare and determine a kind of nano-hydroxyapatite composite material with good antibacterial efficacy on Enterococcusfaecalis (E. faecalis) in vitro. We investigated the antimicrobial activity of four kinds of nano-hydroxyapatite composites, namely, silver/hydroxyapatite composite nanoparticles (Ag/nHA), yttrium/hydroxyapatite composite nanoparticles (Yi/nHA), cerium/hydroxyapatite composite nanoparticles (Ce/nHA), and hydroxyapatite nanoparticles (nHA), against E. faecalis in vitro using the agar diffusion and broth dilution method by measuring the growth inhibition zone and the minimum inhibitory concentration (MIC), respectively. The agar diffusion test results showed that Ag/nHA displayed an obvious growth inhibition zone, whereas Yi/nHA, Ce/nHA, and nHA showed no influence on E. faecalis. The MIC value of Ag/nHA was 1.0 g.L-1, and the three other materials had no effect on E.faecalis even at the high concentration of 32.0 g.L-1. Ag/nHA display a potential antimicrobial efficacy to planktonic E.faecalis. Whereas, the three other kinds of nano-hydroxyapatite composites (Yi/nHA, Ce/nHA, nHA) show no influence.

  6. Efficacy of the biomaterials 3wt%-nanostrontium-hydroxyapatite-enhanced calcium phosphate cement (nanoSr-CPC) and nanoSr-CPC-incorporated simvastatin-loaded poly(lactic-co-glycolic-acid) microspheres in osteogenesis improvement: An explorative multi-phase experimental in vitro/vivo study.

    PubMed

    Masaeli, Reza; Jafarzadeh Kashi, Tahereh Sadat; Dinarvand, Rassoul; Rakhshan, Vahid; Shahoon, Hossein; Hooshmand, Behzad; Mashhadi Abbas, Fatemeh; Raz, Majid; Rajabnejad, Alireza; Eslami, Hossein; Khoshroo, Kimia; Tahriri, Mohammadreza; Tayebi, Lobat

    2016-12-01

    The purpose of this multi-phase explorative in vivo animal/surgical and in vitro multi-test experimental study was to (1) create a 3wt%-nanostrontium hydroxyapatite-enhanced calcium phosphate cement (Sr-HA/CPC) for increasing bone formation and (2) creating a simvastatin-loaded poly(lactic-co-glycolic acid) (SIM-loaded PLGA) microspheres plus CPC composite (SIM-loaded PLGA+nanostrontium-CPC). The third goal was the extensive assessment of multiple in vitro and in vivo characteristics of the above experimental explorative products in vitro and in vivo (animal and surgical studies). Physical and chemical properties of the prepared Sr-HA/CPC were evaluated. MTT assay and alkaline phosphatase activities, and radiological and histological examinations of Sr-HA/CPC, CPC and negative control were compared. X-ray diffraction (XRD) indicated that crystallinity of the prepared cement increased by increasing the powder-to-liquid ratio. Incorporation of Sr-HA into CPC increased MTT assay (biocompatibility) and ALP activity (P<0.05). Histomorphometry showed greater bone formation after 4weeks, after implantation of Sr-HA/CPC in 10 rats compared to implantations of CPC or empty defects in the same rats (n=30, ANOVA P<0.05). METHODS AND RESULTS PERTAINING TO SIM-LOADED PLGA MICROSPHERES+NANOSTRONTIUM-CPC COMPOSITE: After SEM assessment, the produced composite of microspheres and enhanced CPC were implanted for 8weeks in 10 rabbits, along with positive and negative controls, enhanced CPC, and enhanced CPC plus SIM (n=50). In the control group, only a small amount of bone had been regenerated (localized at the boundary of the defect); whereas, other groups showed new bone formation within and around the materials. A significant difference was found in the osteogenesis induced by the groups sham control (16.96±1.01), bone materials (32.28±4.03), nanostrontium-CPC (24.84±2.6), nanostrontium-CPC-simvastatin (40.12±3.29), and SIM-loaded PLGA+nanostrontium-CPC (44.8±6.45) (ANOVA P

  7. Anti-Fas conjugated hyaluronic acid microsphere gels for neural stem cell delivery.

    PubMed

    Shendi, Dalia; Albrecht, Dirk R; Jain, Anjana

    2017-02-01

    Central nervous system (CNS) injuries and diseases result in neuronal damage and loss of function. Transplantation of neural stem cells (NSCs) has been shown to improve locomotor function after transplantation. However, due to the immune and inflammatory response at the injury site, the survival rate of the engrafted cells is low. Engrafted cell viability has been shown to increase when transplanted within a hydrogel. Hyaluronic acid (HA) hydrogels have natural anti-inflammatory properties and the backbone can be modified to introduce bioactive agents, such as anti-Fas, which we have previously shown to promote NSC survival while suppressing immune cell activity in bulk hydrogels in vitro. Although bulk HA hydrogels have shown to promote stem cell survival, microsphere gels for NSC encapsulation and delivery may have additional advantages. In this study, a flow-focusing microfluidic device was used to fabricate either vinyl sulfone-modified HA (VS-HA) or anti-Fas-conjugated HA (anti-Fas HA) microsphere gels encapsulated with NSCs. The majority of encapsulated NSCs remained viable for at least 24 h in the VS-HA and anti-Fas HA microsphere gels. Moreover, T-cells cultured in suspension with the anti-Fas HA microsphere gels had reduced viability after contact with the microsphere gels compared to the media control and soluble anti-Fas conditions. This approach can be adapted to encapsulate various cell types for therapeutic strategies in other physiological systems in order to increase survival by reducing the immune response. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 608-618, 2017. © 2016 Wiley Periodicals, Inc.

  8. Preparation and characterization of selenite substituted hydroxyapatite.

    PubMed

    Ma, Jun; Wang, Yanhua; Zhou, Lei; Zhang, Shengmin

    2013-01-01

    Selenite-substituted hydroxyapatite (Se-HA) with different Se/P ratios was synthesized by a co-precipitation method, using sodium selenite (Na2SeO3) as a Se source. Selenium has been incorporated into the hydroxyapatite lattice by partially replacing phosphate (PO4(3-)) groups with selenite (SeO3(2-)) groups. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) techniques reveal that substitutions of phosphate groups by selenite groups cause lower carbonate groups occupying at phosphate sites and change the lattice parameters of hydroxyapatite. The powders obtained are nano-crystalline hydroxyapatite when the Se/P ratios are not more than 0.1. The particle shape of Se-HA has not been altered compared with selenite-free hydroxyapatite but Se-incorporation reduces the crystallite size. The crystallinity was reduced as the Se/P ratios increased until amorphous phase (Se/P=0.3) appeared in the Se-HA powder obtained, and then another crystal phase presented as calcium selenite hydrate (Se/P=10). In addition, the sintering tests show that the Se-HA powders with the Se/P ratio of 0.1 have thermal stability at 900 °C for 2 h; hence they have great potential in the fabrication of bone repair scaffolds. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Characterization, Corrosion Resistance, and Cell Response of High-Velocity Flame-Sprayed HA and HA/TiO2 Coatings on 316L SS

    NASA Astrophysics Data System (ADS)

    Singh, Tejinder Pal; Singh, Harpreet; Singh, Hazoor

    2012-09-01

    The main aim of this study is to evaluate corrosion and biocompatibility behavior of thermal spray hydroxyapatite (HA) and hydroxyapatite/titania bond (HA/TiO2)-coated 316L stainless steel (316L SS). In HA/TiO2 coatings, TiO2 was used as a bond coat between HA top coat and 316L SS substrate. The coatings were characterized by x-ray diffraction and scanning electron microscopy/energy dispersive spectroscopy, and corrosion resistance determined for the uncoated substrate and the two coatings. The biological behavior was investigated by the cell culture studies using osteosarcoma cell line KHOS-NP (R-970-5). The corrosion resistance of the steel was found to increase after the deposition of the HA and HA/TiO2 bond coatings. Both HA, as well as, HA/TiO2 coatings exhibit excellent bond strength of 49 and 47 MPa, respectively. The cell culture studies showed that HA-coated 316L SS specimens appeared more biocompatible than the uncoated and HA/TiO2-coated 316L SS specimens.

  10. Synthesis, structural properties and thermal stability of Mn-doped hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Paluszkiewicz, Czesława; Ślósarczyk, Anna; Pijocha, Dawid; Sitarz, Maciej; Bućko, Mirosław; Zima, Aneta; Chróścicka, Anna; Lewandowska-Szumieł, Małgorzata

    2010-07-01

    Hydroxyapatite (HA) - Ca 10(PO 4) 6(OH) 2 is a basic inorganic model component of hard biological tissues, such as bones and teeth. The significant property of HA is its ability to exchange Ca 2+ ions, which influences crystallinity, physico-chemical and biological properties of modified hydroxyapatite materials. In this work, FTIR, Raman spectroscopy, XRD, SEM and EDS techniques were used to determine thermal stability, chemical and phase composition of Mn containing hydroxyapatite (MnHA). Described methods confirmed thermal decomposition and phase transformation of MnHA to αTCP, βTCP and formation of Mn 3O 4 depending on sintering temperature and manganese content. In vitro biological evaluation of Mn-modified HA ceramics was also performed using human osteoblast cells.

  11. Differential osteogenic activity of osteoprogenitor cells on HA and TCP/HA scaffold of tissue engineered bone.

    PubMed

    Ng, Angela M H; Tan, K K; Phang, M Y; Aziyati, O; Tan, G H; Isa, M R; Aminuddin, B S; Naseem, M; Fauziah, O; Ruszymah, B H I

    2008-05-01

    Biomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma-derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering. Copyright 2007 Wiley Periodicals, Inc.

  12. Preparation and characterization of bio-composite PEEK/nHA

    NASA Astrophysics Data System (ADS)

    Jin, Y. S.; Bian, C. C.; Zhang, Z. Q.; Zhao, Y.; Yang, L.

    2017-01-01

    PEEK/nHA composite material, with excellent mechanical property as polyetheretherketone (PEEK) and biological activity as hydroxyapatite (HA), has attracted wide attention of medical experts and materials science experts. The addition of hydroxyapatite was the decisive factor for biological activity in PEEK/nHA composite. In this paper, acicular nanohydroxyapatite was prepared by chemical precipitation method with Ca(NO3)2, (NH4)2HPO4 as raw material; PEEK/nHA composite was prepared by solution blending and vacuum sintering method. The composite was characterized with FT-IR, XRD, DSC, TG and mechanical property test. Results showed that the composite has good thermal stability and compressive property when the mass ratio of PEEK to nHA is 10:3; and high nHA content can improve the biological activity of the composite, which can meet the basic requirements for bone tissue engineering scaffold.

  13. Comparison between PCL/hydroxyapatite (HA) and PCL/halloysite nanotube (HNT) composite scaffolds prepared by co-extrusion and gas foaming.

    PubMed

    Jing, Xin; Mi, Hao-Yang; Turng, Lih-Sheng

    2017-03-01

    In this work, three-dimensional poly(caprolactone) (PCL) tissue engineering scaffolds were prepared by co-extrusion and gas foaming. Biocompatible hydroxyapatite (HA) and halloysite nanotubes (HNT) were added to the polymer matrix to enhance the mechanical properties and bioactivity of the composite scaffolds. The effects of HA and HNT on the rheological behavior, microstructure, and mechanical properties of the composite scaffolds were systematically compared. It was found that the HNT improved viscosity more significantly than HA, and reduced the pore size of scaffolds, while the mechanical performance of PCL/HNT scaffolds was higher than PCL/HA scaffolds with the same filler content. Human mesenchymal stem cells (hMSCs) were used as the cell model to compare the biological properties of two composite scaffolds. The results demonstrated that cells could survive on all scaffolds, and showed a more flourishing living state on the composite scaffolds. The cell differentiation for 5% HA and 1% HNT scaffolds were significantly higher than other scaffolds, while the differentiation of 5% HNT scaffolds was lower than that of 1% HNT scaffolds mainly because of the reduced pore size and pore interconnectivity. Therefore, this study suggested that, with proper filler content and control of microstructure through processing, HNT could be a suitable substitute for HA for bone tissue engineering to reduce the cost and improve mechanical performance. Copyright © 2016. Published by Elsevier B.V.

  14. Electrophoretic co-deposition of PEEK-hydroxyapatite composite coatings for biomedical applications.

    PubMed

    Baştan, Fatih E; Atiq Ur Rehman, Muhammad; Avcu, Yasemin Yıldıran; Avcu, Egemen; Üstel, Fatih; Boccaccini, Aldo R

    2018-05-03

    This study focuses on the optimization of electrophoretic deposition (EPD) and suspension parameters for producing PEEK-hydroxyapatite (HA) coatings with feasible microstructure, adhesion strength, and in-vitro bioactivity. Nanostructured hydroxyapatite (HA) micro-granules were incorporated with PEEK to form PEEK-hydroxyapatite composite coatings via EPD. After EPD, a heat-treatment at 375 °C was applied for densification of the coatings and for enhancing the adhesion between the coatings and the substrates. It was found that both adhesion strength and in-vitro bioactivity of the coatings were dependent on the PEEK and HA relative contents. Thus, increasing the amount of HA improved the bioactivity while decreased the adhesion strength of the coatings. Apatite-like layer formation was observed on coatings with high HA content after incubation for three days in simulated body fluid (SBF). Finally, a deposition mechanism was proposed for the EPD of the PEEK-hydroxyapatite composite system. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Nanocrystalline hydroxyapatite enriched in selenite and manganese ions: physicochemical and antibacterial properties

    NASA Astrophysics Data System (ADS)

    Kolmas, Joanna; Groszyk, Ewa; Piotrowska, Urszula

    2015-07-01

    In this work, we used the co-precipitation method to synthesize hydroxyapatite (Mn-SeO3-HA) containing both selenium IV (approximately 3.60 wt.%) and manganese II (approximately 0.29 wt.%). Pure hydroxyapatite (HA), hydroxyapatite-containing manganese (II) ions (Mn-HA), and hydroxyapatite-containing selenite ions alone (SeO3-HA), prepared with the same method, were used as reference materials. The structures and physicochemical properties of all the obtained samples were investigated. PXRD studies showed that the obtained materials were homogeneous and consisted of apatite phase. Introducing selenites into the hydroxyapatite crystals considerably affects the size and degree of ordering. Experiments with transmission electron microscopy (TEM) showed that Mn-SeO3-HA crystals are very small, needle-like, and tend to form agglomerates. Fourier transform infrared spectroscopy (FT-IR) and solid-state nuclear magnetic resonance (ssNMR) were used to analyze the structure of the obtained material. Preliminary microbiological tests showed that the material demonstrated antibacterial activity against Staphylococcus aureus, yet such properties were not confirmed regarding Escherichia coli. PACS codes: 61, 76, 81

  16. Synthesis of sodium caseinate-calcium carbonate microspheres and their mineralization to bone-like apatite

    NASA Astrophysics Data System (ADS)

    Xu, Zhewu; Liang, Guobin; Jin, Lin; Wang, Zhenling; Xing, Chao; Jiange, Qing; Zhang, Zhiguang

    2014-06-01

    Phosphoproteins can induce and stabilize calcium carbonate (CaCO3) vaterite, which has desirable features for high reactivity. The purpose of this study was to synthesize bioactive CaCO3 microspheres for bone regeneration. Sodium caseinate (NaCas)-containing CaCO3 microspheres, with the crystal phase of vaterite, were synthesized by fast precipitation in an aqueous solution of CaCl2, Na2CO3, and 2 mg/mL of NaCas. The uniform microspheres exhibited rougher surfaces and lower negative charges than CaCO3 particles without NaCas addition. Fourier-transform infrared spectroscopy (FT-IR) of the microspheres showed characteristic peaks or bands corresponding to phosphate and hydroxyl groups. Thermogravimetric analysis (TGA) curves exhibited approximately 5% weight loss below 600 °C due to the decomposition of NaCas. Scanning electron microscope (SEM) images showed lath-like hydroxyapatite (HAp) on the surface after soaking in simulated body fluid (SBF) at 37 °C for 5 and 10 days. Energy dispersive X-ray spectrometry (EDS) revealed that the agglomerates were composed of Ca, C, O, P, Na, and Mg elements, and the Ca/P ratios ranged from 1.53 to 1.56. X-ray diffraction (XRD) patterns exhibited peaks characteristic of hydroxyapatite. The results of this study demonstrated that the addition of NaCas induced the formation of vaterite microspheres which possesses an enhanced apatite formation after soaking in SBF at 37 °C for 5 and 10 days. These NaCas-CaCO3 microspheres may be a potential biomaterial for bone regeneration.

  17. Hydroxyapatite reinforced collagen scaffolds with improved architecture and mechanical properties.

    PubMed

    Kane, Robert J; Weiss-Bilka, Holly E; Meagher, Matthew J; Liu, Yongxing; Gargac, Joshua A; Niebur, Glen L; Wagner, Diane R; Roeder, Ryan K

    2015-04-01

    Hydroxyapatite (HA) reinforced collagen scaffolds have shown promise for synthetic bone graft substitutes and tissue engineering scaffolds. Freeze-dried HA-collagen scaffolds are readily fabricated and have exhibited osteogenicity in vivo, but are limited by an inherent scaffold architecture that results in a relatively small pore size and weak mechanical properties. In order to overcome these limitations, HA-collagen scaffolds were prepared by compression molding HA reinforcements and paraffin microspheres within a suspension of concentrated collagen fibrils (∼ 180 mg/mL), cross-linking the collagen matrix, and leaching the paraffin porogen. HA-collagen scaffolds exhibited an architecture with high porosity (85-90%), interconnected pores ∼ 300-400 μm in size, and struts ∼ 3-100 μm in thickness containing 0-80 vol% HA whisker or powder reinforcements. HA reinforcement enabled a compressive modulus of up to ∼ 1 MPa, which was an order of magnitude greater than unreinforced collagen scaffolds. The compressive modulus was also at least one order of magnitude greater than comparable freeze-dried HA-collagen scaffolds and two orders of magnitude greater than absorbable collagen sponges used clinically. Moreover, scaffolds reinforced with up to 60 vol% HA exhibited fully recoverable elastic deformation upon loading to 50% compressive strain for at least 100,000 cycles. Thus, the scaffold mechanical properties were well-suited for surgical handling, fixation, and bearing osteogenic loads during bone regeneration. The scaffold architecture, permeability, and composition were shown to be conducive to the infiltration and differentiation of adipose-derive stromal cells in vitro. Acellular scaffolds were demonstrated to induce angiogenesis and osteogenesis after subcutaneous ectopic implantation by recruiting endogenous cell populations, suggesting that the scaffolds were osteoinductive. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights

  18. Preparation and characterization of hydroxyapatite/sodium alginate biocomposites for bone implant application

    NASA Astrophysics Data System (ADS)

    Kanasan, Nanthini; Adzila, Sharifah; Suid, Mohd Syafiq; Gurubaran, P.

    2016-07-01

    In biomedical fields, synthetic scaffolds are being improved by using the ceramics, polymers and composites materials to avoid the limitations of allograft. Ceramic-polymer composites are appearing to be the most successful bone graft substitute in human body. The natural bones itself are well-known as composite of collagen and hydroxyapatite. In this research, precipitation method was used to synthesis hydroxyapatite (HA)/sodium alginate (SA) in various parameters. This paper describes the hydroxyapatite/sodium alginate biocomposite which suitable for use in bone defects or regeneration of bone through the characterizations which include FTIR, FESEM, EDS and DTA. In FTIR, the characteristi peaks of PO4-3 and OH- groups which corresponding to hydroxyapatite are existed in the mixing powders. The needle-size particle of hydroxyapatite/ alginate (HA/SA) are observed in FESEM in the range of 15.8nm-38.2nm.EDS confirmed the existence of HA/SA composition in the mixing powders. There is an endothermic peak which corresponds to the dehydration and the loss of physically adsorbed water molecules of the hydroxyapatite (HA)/sodium alginate (SA) powder which are described in DTA.

  19. High strength yttria-reinforced HA scaffolds fabricated via honeycomb ceramic extrusion.

    PubMed

    Elbadawi, M; Shbeh, M

    2018-01-01

    The present study investigated the effects of hydroxyapatite (HA) reinforced with yttria on porous scaffolds fabricated via honeycomb ceramic extrusion. Yttria was selected as it has been demonstrated to toughen other ceramics. Moreover, yttria has been surmised to suppress dehydroxylation in HA, a characteristic that prefigures decomposition thereof during sintering into mechanically weaker phases. However, the compressive strength of yttria-reinforced hydroxyapatite (Y-HA) porous scaffolds has hitherto not been reported. Y-HA was synthesised by calcining a commercially available HA with 10wt% yttria at 1000°C. Y-HA was then fabricated into porous scaffolds using an in-house honeycomb extruder, and subsequently sintered at 1200 and 1250°C. The results were compared to the uncalcined as-received commercial powder (AR-HA) and calcined pure HA powder at 1000°C (C-HA). It was discovered that calcination alone caused marked improvements to the stoichiometry, thermal stability, porosity and compressive strength of scaffolds. The improvements were ascribed to the calcined powders with less susceptibility to both agglomeration and enhanced densification. Still, differences were observed between C-HA and Y-HA at 1250°C. The compressive strength increased from 105.9 to 127.3MPa, a larger microporosity was descried and the HA matrix in Y-HA was more stoichiometric. The latter was confirmed by XRD and EDS analyses. Therefore, it was concluded that the reinforcing of hydroxyapatite with yttria improved the compressive strength and suppressed dehydroxylation of porous HA scaffolds. In addition, the compressive strength achieved demonstrated great potential for load-bearing application. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Surface characterization of colloidal-sol gel derived biphasic HA/FA coatings.

    PubMed

    Cheng, Kui; Zhang, Sam; Weng, Wenjian

    2007-10-01

    Hydroxyapatite (HA) powders are ultrasonically dispersed in the precursor of fluoridated hydroxyapatite (FHA) or fluorapatite (FA) to form a "colloidal sol". HA/FA biphasic coatings are prepared on Ti6Al4V substrate via dip coating, 150 degrees C drying and 600 degrees C firing. The coatings show homogenous distribution of HA particles in the FA matrix. The relative phase proportion can be tailored by the amount of HA in the colloidal sol. The surfaces of the coatings consist of two kinds of distinct domains: HA and FA, resulting in a compositionally heterogeneous surface. The biphasic coating surface becomes increasingly rougher with HA powders, from around 200 nm of pure FA to 400-600 nm in Ra of biphasic coatings. The rougher biphasic HA/FA surfaces with chemically controllable domains will favor cell attachment, apatite layer deposition and necessary dissolution in clinical applications.

  1. The Effect of Titanium Dioxide (TiO2) Nanoparticles on Hydroxyapatite (HA)/TiO2 Composite Coating Fabricated by Electrophoretic Deposition (EPD)

    NASA Astrophysics Data System (ADS)

    Amirnejad, M.; Afshar, A.; Salehi, S.

    2018-05-01

    Composite coatings of Hydroxyapatite (HA) with ceramics, polymers and metals are used to modify the surface structure of implants. In this research, HA/TiO2 composite coating was fabricated by electrophoretic deposition (EPD) on 316 stainless steel substrate. HA/TiO2 composite coatings with 5, 10 and 20 wt.% of TiO2, deposited at 40 V and 90 s as an optimum condition. The samples coated at this condition led to an adherent, continuous and crack-free coating. The influence of TiO2 content was studied by performing different characterization methods such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), corrosion resistance in simulated body fluid (SBF), coating's dissolution rate in physiological solution and bond strength to the substrate. The results showed that the higher amount of TiO2 in the composite coating led to increase in bond strength of coating to stainless steel substrate from 3 MPa for HA coating to 5.5 MPa for HA-20 wt.% TiO2 composite coating. In addition, it caused to reduction of corrosion current density of samples in the SBF solution from 18.92 μA/cm2 for HA coating to 6.35 μA/cm2 for HA-20 wt.% TiO2 composite coating.

  2. The Effect of Titanium Dioxide (TiO2) Nanoparticles on Hydroxyapatite (HA)/TiO2 Composite Coating Fabricated by Electrophoretic Deposition (EPD)

    NASA Astrophysics Data System (ADS)

    Amirnejad, M.; Afshar, A.; Salehi, S.

    2018-04-01

    Composite coatings of Hydroxyapatite (HA) with ceramics, polymers and metals are used to modify the surface structure of implants. In this research, HA/TiO2 composite coating was fabricated by electrophoretic deposition (EPD) on 316 stainless steel substrate. HA/TiO2 composite coatings with 5, 10 and 20 wt.% of TiO2, deposited at 40 V and 90 s as an optimum condition. The samples coated at this condition led to an adherent, continuous and crack-free coating. The influence of TiO2 content was studied by performing different characterization methods such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), corrosion resistance in simulated body fluid (SBF), coating's dissolution rate in physiological solution and bond strength to the substrate. The results showed that the higher amount of TiO2 in the composite coating led to increase in bond strength of coating to stainless steel substrate from 3 MPa for HA coating to 5.5 MPa for HA-20 wt.% TiO2 composite coating. In addition, it caused to reduction of corrosion current density of samples in the SBF solution from 18.92 μA/cm2 for HA coating to 6.35 μA/cm2 for HA-20 wt.% TiO2 composite coating.

  3. Nano-crystalline hydroxyapatite bio-mineral for the treatment of strontium from aqueous solutions.

    PubMed

    Handley-Sidhu, Stephanie; Renshaw, Joanna C; Yong, Ping; Kerley, Robert; Macaskie, Lynne E

    2011-01-01

    Hydroxyapatites were analysed using electron microscopy, X-ray diffraction (XRD) and X-ray fluorescence (XRF) analysis. Examination of a bacterially produced hydroxyapatite (Bio-HA) by scanning electron microscopy showed agglomerated nano-sized particles; XRD analysis confirmed that the Bio-HA was hydroxyapatite, with an organic matter content of 7.6%; XRF analysis gave a Ca/P ratio of 1.55, also indicative of HA. The size of the Bio-HA crystals was calculated as ~25 nm from XRD data using the Scherrer equation, whereas Comm-HA powder size was measured as ≤ 50 μm. The nano-crystalline Bio-HA was ~7 times more efficient in removing Sr(2+) from synthetic groundwater than Comm-HA. Dissolution of HA as indicated by the release of phosphate into the solution phase was higher in the Comm-HA than the Bio-HA, indicating a more stable biomaterial which has a potential for the remediation of contaminated sites.

  4. Synthesis of novel quaternary silica hybrid bioactive microspheres.

    PubMed

    Angelopoulou, A; Efthimiadou, E Κ; Kordas, G

    2018-01-01

    To survey the preparation of novel hybrid microspheres of quaternary silicate glassy composition (SiO 2 P 2 O 5 CaONa 2 O) and the prospect of using them as an osteogenic system with enhanced bioactive properties for the development of hydroxyapatite. In line with our previous synthetic procedure a two-step process was followed, wherein polystyrene (PS) microspheres were prepared by the emulsifier free-emulsion polymerization method and constituted the core for the sol-gel coating of the silicate inorganic shell. The development of the hybrid microspheres was based on silane and phosphate precursors and was assesses at different ratio of ethanol/water (of 9/1, 4/1, and 2/1, in mL) and at varied ammonia concentration of 4.8-1.0 mL. The hybrid microspheres had an average size ranged between 350 and 550 nm according to SEM, depending on the ethanol/water solution rate and ammonia content. The final microspheres probably exhibited a porous-like structure through the formation of diffused voids along with the low carbon content of the EDX analysis, which could be regulated by the catalyst content. The hybrid microspheres exhibited effective in vitro bioactivity assessed in simulated body fluids (SBF). Quaternary hybrid silica microspheres were effectively synthesized. The bioassay evaluation of the final microspheres revealed the rapid in vitro formation of a bone-like apatite layer. The results verify the bioactivity of the microspheres and promote further research of their suitability on regenerative treatment of bone abnormalities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 112-120, 2018. © 2016 Wiley Periodicals, Inc.

  5. Zinc-Containing Hydroxyapatite Enhances Cold-Light-Activated Tooth Bleaching Treatment In Vitro

    PubMed Central

    Shi, Xinchang

    2017-01-01

    Cold-light bleaching treatment has grown to be a popular tooth whitening procedure in recent years, but its side effect of dental enamel demineralization is a widespread problem. The aim of this study was to synthesize zinc-substituted hydroxyapatite as an effective biomaterial to inhibit demineralization or increase remineralization. We synthesized zinc-substituted hydroxyapatite containing different zinc concentrations and analysed the product using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and energy dispersive spectrometer (EDS). The biological assessment of Zn-HA was conducted by CCK-8 assay and bacterial inhibition tests. pH cycling was performed to estimate the effect of Zn-HA on the enamel surface after cold-light bleaching treatment. The XRD, FTIR, and EDS results illustrated that zinc ions and hydroxyapatite combined in two forms: (1) Zn2+ absorbed on the surface of HA crystal and (2) Zn2+ incorporated into the lattice of HA. The results indicated that 2% Zn-HA, 4% Zn-HA, and 8% Zn-HA effectively inhibited the growth of bacteria yet showed poor biocompatibility, whereas 1% Zn-HA positively affected osteoblast proliferation. The XRD and scanning electron microscopy (SEM) results showed that the use of Zn-HA in pH cycling is obviously beneficial for enamel remineralization. Zinc-substituted hydroxyapatite could be a promising biomaterial for use in cold-light bleaching to prevent enamel demineralization. PMID:29159178

  6. Reaction of sodium calcium borate glasses to form hydroxyapatite.

    PubMed

    Han, Xue; Day, Delbert E

    2007-09-01

    This study investigated the transformation of two sodium calcium borate glasses to hydroxyapatite (HA). The chemical reaction was between either 1CaO . 2Na(2)O . 6B(2)O(3) or 2CaO . 2Na(2)O . 6B(2)O(3) glass and a 0.25 M phosphate (K(2)HPO(4)) solution at 37, 75 and 200 degrees C. Glass samples in the form of irregular particles (125-180 microm) and microspheres (45-90 and 125-180 microm) were used in order to understand the reaction mechanism. The effect of glass composition (calcium content) on the weight loss rate and reaction temperature on crystal size, crystallinity and grain shape of the reaction products were studied. Carbonated HA was made by dissolving an appropriate amount of carbonate (K(2)CO(3)) in the 0.25 M phosphate solution. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used to characterize the reaction products. The results show that sodium calcium borate glasses can be transformed to HA by reacting with a phosphate solution. It is essentially a process of dissolution of glass and precipitation of HA. The transformation begins from an amorphous state to calcium-deficient HA without changing the size and shape of the original glass sample. Glass with a lower calcium content (1CaO . 2Na(2)O . 6B(2)O(3)), or reacted at an elevated temperature (75 degrees C), has a higher reaction rate. The HA crystal size increases and grain shape changes from spheroidal to cylindrical as temperature increases from 37 to 200 degrees C. Increase in carbonate concentration can also decrease the crystal size and yield a more needle-like grain shape.

  7. Biomedical potential of chitosan/HA and chitosan/β-1,3-glucan/HA biomaterials as scaffolds for bone regeneration--A comparative study.

    PubMed

    Przekora, Agata; Palka, Krzysztof; Ginalska, Grazyna

    2016-01-01

    The aim of this work was to compare biomedical potential of chitosan/hydroxyapatite (chit/HA) and novel chitosan/β-1,3-glucan/hydroxyapatite (chit/glu/HA) materials as scaffolds for bone regeneration via characterization of their biocompatibility, porosity, mechanical properties, and water uptake behaviour. Biocompatibility of the scaffolds was assessed in direct-contact with the materials using normal human foetal osteoblast cell line. Cytotoxicity and osteoblast proliferation rate were evaluated. Porosity was assessed using computed microtomography analysis and mechanical properties were determined by compression testing. Obtained results demonstrated that chit/HA scaffold possessed significantly better mechanical properties (compressive strength: 1.23 MPa, Young's modulus: 0.46 MPa) than chit/glu/HA material (compressive strength: 0.26 MPa, Young's modulus: 0.25 MPa). However, addition of bacterial β-1,3-glucan to the chit/HA scaffold improved its flexibility and porosity. Moreover, chit/glu/HA scaffold revealed significantly higher water uptake capability (52.6% after 24h of soaking) compared to the chit/HA (30.7%) and thus can serve as a very good drug delivery carrier. Chit/glu/HA scaffold was also more favourable to osteoblast survival (near 100% viability after 24-h culture), proliferation, and spreading compared to the chit/HA (63% viability). The chit/glu/HA possesses better biomedical potential than chit/HA scaffold. Nevertheless, poor mechanical properties of the chit/glu/HA limit its application to non-load bearing implantation area. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Hydroxyapatite fiber reinforced poly(alpha-hydroxy ester) foams for bone regeneration

    NASA Technical Reports Server (NTRS)

    Thomson, R. C.; Yaszemski, M. J.; Powers, J. M.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    A process has been developed to manufacture biodegradable composite foams of poly(DL-lactic-co-glycolic acid) (PLGA) and hydroxyapatite short fibers for use in bone regeneration. The processing technique allows the manufacture of three-dimensional foam scaffolds and involves the formation of a composite material consisting of a porogen material (either gelatin microspheres or salt particles) and hydroxyapatite short fibers embedded in a PLGA matrix. After the porogen is leached out, an open-cell composite foam remains which has a pore size and morphology defined by the porogen. By changing the weight fraction of the leachable component it was possible to produce composite foams with controlled porosities ranging from 0.47 +/- 0.02 to 0.85 +/- 0.01 (n = 3). Up to a polymer:fiber ratio of 7:6, short hydroxyapatite fibers served to reinforce low-porosity PLGA foams manufactured using gelatin microspheres as a porogen. Foams with a compressive yield strength up to 2.82 +/- 0.63 MPa (n = 3) and a porosity of 0.47 +/- 0.02 (n = 3) were manufactured using a polymer:fiber weight ratio of 7:6. In contrast, high-porosity composite foams (up to 0.81 +/- 0.02, n = 3) suitable for cell seeding were not reinforced by the introduction of increasing quantities of hydroxyapatite short fibers. We were therefore able to manufacture high-porosity foams which may be seeded with cells but which have minimal compressive yield strength, or low porosity foams with enhanced osteoconductivity and compressive yield strength.

  9. Determination of Microstructural Parameters of Nanocrystalline Hydroxyapatite Prepared by Mechanical Alloying Method

    NASA Astrophysics Data System (ADS)

    Joughehdoust, Sedigheh; Manafi, Sahebali

    2011-12-01

    Hydroxyapatite [HA, Ca10(PO4)6(OH)2] is chemically similar to the mineral component of bones and hard tissues. HA can support bone ingrowth and osseointegration when used in orthopaedic, dental and maxillofacial applications. In this research, HA nanostructure was synthesized by mechanical alloying method. Phase development, particle size and morphology of HA were investigated by X-ray diffraction (XRD) pattern, zetasizer instrument, scanning electron microscopy (SEM), respectively. XRD pattern has been used to determination of the microstructural parameters (crystallite size, lattice parameters and crystallinity percent) by Williamson-Hall equation, Nelson-Riley method and calculating the areas under the peaks, respectively. The crystallite size and particle size of HA powders were in nanometric scales. SEM images showed that some parts of HA particles have agglomerates. The ratio of lattice parameters of synthetic hydroxyapatite (c/a = 0.73) was determined in this study is the same as natural hydroxyapatite structure.

  10. Hydroxyapatite Fibers: A Review of Synthesis Methods

    NASA Astrophysics Data System (ADS)

    Qi, Mei-Li; He, Kun; Huang, Zhen-Nan; Shahbazian-Yassar, Reza; Xiao, Gui-Yong; Lu, Yu-Peng; Shokuhfar, Tolou

    2017-08-01

    Hydroxyapatite (HA) exhibits excellent biocompatibility, bioactivity, osteoconductivity, non-toxicity and so on, making it a perfect candidate for biomedical applications. However, HA is not qualified to be used in load-bearing sites due to its poor flexural strength and fracture toughness. Design, synthesis and application of fibrous HA is a promising strategy to overcome the inherent brittleness. This review provides a brief description of HA and hydroxyapatite fiber (HAF), then introduces different synthesis methods of HAF and highlights the inherent merits and drawbacks involved in each method. Finally, the future perspectives in this active research area are given. The purpose of this review is to acquaint the reader with this promising new field of biomaterials research and with emphasis on recent techniques to obtain continuous, uniform and long HAF.

  11. Micro- and nano-hydroxyapatite as active reinforcement for soft biocomposites.

    PubMed

    Munarin, F; Petrini, P; Gentilini, R; Pillai, R S; Dirè, S; Tanzi, M C; Sglavo, V M

    2015-01-01

    Pectin-based biocomposite hydrogels were produced by internal gelation, using different hydroxyapatite (HA) powders from commercial source or synthesized by the wet chemical method. HA possesses the double functionality of cross-linking agent and inorganic reinforcement. The mineralogical composition, grain size, specific surface area and microstructure of the hydroxyapatite powders are shown to strongly influence the properties of the biocomposites. Specifically, the grain size and specific surface area of the HA powders are strictly correlated to the gelling time and rheological properties of the hydrogels at room temperature. Pectin pH is also significant for the formation of ionic cross-links and therefore for the hydrogels stability at higher temperatures. The obtained results point out that micrometric-size hydroxyapatite can be proposed for applications which require rapid gelling kinetics and improved mechanical properties; conversely the nanometric hydroxyapatite synthesized in the present work seems the best choice to obtain homogeneous hydrogels with more easily controlled gelling kinetics. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Real-Time Protein and Cell Binding Measurements on Hydroxyapatite Coatings

    PubMed Central

    Vilardell, A. M.; Cinca, N.; Jokinen, A.; Garcia-Giralt, N.; Dosta, S.; Cano, I. G.; Guilemany, J. M.

    2016-01-01

    Although a lot of in vitro and in vivo assays have been performed during the last few decades years for hydroxyapatite bioactive coatings, there is a lack of exploitation of real-time in vitro interaction measurements. In the present work, real-time interactions for a plasma sprayed hydroxyapatite coating were measured by a Multi-Parametric Surface Plasmon Resonance (MP-SPR), and the results were compared with standard traditional cell viability in vitro assays. MP-SPR is proven to be suitable not only for measurement of molecule–molecule interactions but also molecule–material interaction measurements and cell interaction. Although SPR is extensively utilized in interaction studies, recent research of protein or cell adsorption on hydroxyapatite coatings for prostheses applications was not found. The as-sprayed hydroxyapatite coating resulted in 62.4% of crystalline phase and an average thickness of 24 ± 6 μm. The MP-SPR was used to measure lysozyme protein and human mesenchymal stem cells interaction to the hydroxyapatite coating. A comparison between the standard gold sensor and Hydroxyapatite (HA)-plasma coated sensor denoted a clearly favourable cell attachment on HA coated sensor as a significantly higher signal of cell binding was detected. Moreover, traditional cell viability and proliferation tests showed increased activity with culture time indicating that cells were proliferating on HA coating. Cells show homogeneous distribution and proliferation along the HA surface between one and seven days with no significant mortality. Cells were flattened and spread on rough surfaces from the first day, with increasing cytoplasmatic extensions during the culture time. PMID:27618911

  13. Enhancement of Cell-Based Therapeutic Angiogenesis Using a Novel Type of Injectable Scaffolds of Hydroxyapatite-Polymer Nanocomposite Microspheres

    PubMed Central

    Koyama, Hidenori; Okada, Masahiro; Tanaka, Shinji; Shoji, Tetsuo; Emoto, Masanori; Furuzono, Tsutomu; Nishizawa, Yoshiki; Inaba, Masaaki

    2012-01-01

    Background Clinical trials demonstrate the effectiveness of cell-based therapeutic angiogenesis in patients with severe ischemic diseases; however, their success remains limited. Maintaining transplanted cells in place are expected to augment the cell-based therapeutic angiogenesis. We have reported that nano-hydroxyapatite (HAp) coating on medical devices shows marked cell adhesiveness. Using this nanotechnology, HAp-coated poly(l-lactic acid) (PLLA) microspheres, named nano-scaffold (NS), were generated as a non-biological, biodegradable and injectable cell scaffold. We investigate the effectiveness of NS on cell-based therapeutic angiogenesis. Methods and Results Bone marrow mononuclear cells (BMNC) and NS or control PLLA microspheres (LA) were intramuscularly co-implanted into mice ischemic hindlimbs. When BMNC derived from enhanced green fluorescent protein (EGFP)-transgenic mice were injected into ischemic muscle, the muscle GFP level in NS+BMNC group was approximate fivefold higher than that in BMNC or LA+BMNC groups seven days after operation. Kaplan-Meier analysis demonstrated that NS+BMNC markedly prevented hindlimb necrosis (P<0.05 vs. BMNC or LA+BMNC). NS+BMNC revealed much higher induction of angiogenesis in ischemic tissues and collateral blood flow confirmed by three-dimensional computed tomography angiography than those of BMNC or LA+BMNC groups. NS-enhanced therapeutic angiogenesis and arteriogenesis showed good correlations with increased intramuscular levels of vascular endothelial growth factor and fibroblast growth factor-2. NS co-implantation also prevented apoptotic cell death of transplanted cells, resulting in prolonged cell retention. Conclusion A novel and feasible injectable cell scaffold potentiates cell-based therapeutic angiogenesis, which could be extremely useful for the treatment of severe ischemic disorders. PMID:22529991

  14. Intercalated chitosan/hydroxyapatite nanocomposites: Promising materials for bone tissue engineering applications.

    PubMed

    Nazeer, Muhammad Anwaar; Yilgör, Emel; Yilgör, Iskender

    2017-11-01

    Preparation and characterization of chitosan/hydroxyapatite (CS/HA) nanocomposites displaying an intercalated structure is reported. Hydroxyapatite was synthesized through sol-gel process. Formic acid was introduced as a new solvent to obtain stable dispersions of nano-sized HA particles in polymer solution. CS/HA dispersions with HA contents of 5, 10 and 20% by weight were prepared. Self-assembling of HA nanoparticles during the drying of the solvent cast films led to the formation of homogeneous CS/HA nanocomposites. Composite films were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-rays (EDX) analysis, Fourier transform infrared (FTIR) spectroscopy, X-rays diffraction (XRD) analysis and thermogravimetric analysis (TGA). SEM and AFM confirmed the presence of uniformly distributed HA nanoparticles on the chitosan matrix surface. XRD patterns and cross-sectional SEM images showed the formation of layered nanocomposites. Complete degradation of chitosan matrix in TGA experiments, led to the formation of nanoporous 3D scaffolds containing hydroxyapatite, β-tricalcium phosphate and calcium pyrophosphate. CS/HA composites can be considered as promising materials for bone tissue engineering applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Carboxylated Agarose (CA)-Silk Fibroin (SF) Dual Confluent Matrices Containing Oriented Hydroxyapatite (HA) Crystals: Biomimetic Organic/Inorganic Composites for Tibia Repair.

    PubMed

    Hu, Jing-Xiao; Ran, Jia-Bing; Chen, Si; Jiang, Pei; Shen, Xin-Yu; Tong, Hua

    2016-07-11

    By in situ combining the dual cross-linking matrices of the carboxylated agarose (CA) and the silk fibroin (SF) with the hydroxyapatite (HA) crystals, the CA-SF/HA composites with optimal physicochemical and biological properties were obtained, which were designed to meet the clinical needs of load-bearing bone repair. With the synergistic modulation of the dual organic matrices, the HA nanoparticles presented sheet and rod morphologies due to the preferred orientation, which successfully simulated the biomineralization in nature. The chemical reactivity of the native agarose (NA) was significantly enhanced via carboxylation, and the CA exhibited higher thermal stability than the NA. In the presence of SF, the composites showed optimal mechanical properties that could meet the standard of bone repair. The degradation of the composites in the presence of CA and SF was significantly delayed such that the degradation rate of the implant could satisfy the growth rate of the newly formed bone tissue. The in vitro tests confirmed that the CA-SF/HA composite scaffolds enabled the MG63 cells to proliferate and differentiate well, and the CA/HA composite presented greater capability of promoting the cell behaviors than the NA/HA composite. After 24 days of implantation, newly formed bone was observed at the tibia defect site and around the implant. Extensive osteogenesis was presented in the rats treated with the CA-SF/HA composites. In general, the CA-SF/HA composites prepared in this work had the great potential to be applied for repairing large bone defects.

  16. Evaluation of zinc-doped mesoporous hydroxyapatite microspheres for the construction of a novel biomimetic scaffold optimized for bone augmentation

    PubMed Central

    Yu, Weilin; Sun, Tuan-Wei; Qi, Chao; Ding, Zhenyu; Zhao, Huakun; Zhao, Shichang; Shi, Zhongmin; Zhu, Ying-Jie; Chen, Daoyun; He, Yaohua

    2017-01-01

    Biomaterials with high osteogenic activity are desirable for sufficient healing of bone defects resulting from trauma, tumor, infection, and congenital abnormalities. Synthetic materials mimicking the structure and composition of human trabecular bone are of considerable potential in bone augmentation. In the present study, a zinc (Zn)-doped mesoporous hydroxyapatite microspheres (Zn-MHMs)/collagen scaffold (Zn-MHMs/Coll) was developed through a lyophilization fabrication process and designed to mimic the trabecular bone. The Zn-MHMs were synthesized through a microwave-hydrothermal method by using creatine phosphate as an organic phosphorus source. Zn-MHMs that consist of hydroxyapatite nanosheets showed relatively uniform spherical morphology, mesoporous hollow structure, high specific surface area, and homogeneous Zn distribution. They were additionally investigated as a drug nanocarrier, which was efficient in drug delivery and presented a pH-responsive drug release behavior. Furthermore, they were incorporated into the collagen matrix to construct a biomimetic scaffold optimized for bone tissue regeneration. The Zn-MHMs/Coll scaffolds showed an interconnected pore structure in the range of 100–300 μm and a sustained release of Zn ions. More importantly, the Zn-MHMs/Coll scaffolds could enhance the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells. Finally, the bone defect repair results of critical-sized femoral condyle defect rat model demonstrated that the Zn-MHMs/Coll scaffolds could enhance bone regeneration compared with the Coll or MHMs/Coll scaffolds. The results suggest that the biomimetic Zn-MHMs/Coll scaffolds may be of enormous potential in bone repair and regeneration. PMID:28392688

  17. Evaluation of zinc-doped mesoporous hydroxyapatite microspheres for the construction of a novel biomimetic scaffold optimized for bone augmentation.

    PubMed

    Yu, Weilin; Sun, Tuan-Wei; Qi, Chao; Ding, Zhenyu; Zhao, Huakun; Zhao, Shichang; Shi, Zhongmin; Zhu, Ying-Jie; Chen, Daoyun; He, Yaohua

    2017-01-01

    Biomaterials with high osteogenic activity are desirable for sufficient healing of bone defects resulting from trauma, tumor, infection, and congenital abnormalities. Synthetic materials mimicking the structure and composition of human trabecular bone are of considerable potential in bone augmentation. In the present study, a zinc (Zn)-doped mesoporous hydroxyapatite microspheres (Zn-MHMs)/collagen scaffold (Zn-MHMs/Coll) was developed through a lyophilization fabrication process and designed to mimic the trabecular bone. The Zn-MHMs were synthesized through a microwave-hydrothermal method by using creatine phosphate as an organic phosphorus source. Zn-MHMs that consist of hydroxyapatite nanosheets showed relatively uniform spherical morphology, mesoporous hollow structure, high specific surface area, and homogeneous Zn distribution. They were additionally investigated as a drug nanocarrier, which was efficient in drug delivery and presented a pH-responsive drug release behavior. Furthermore, they were incorporated into the collagen matrix to construct a biomimetic scaffold optimized for bone tissue regeneration. The Zn-MHMs/Coll scaffolds showed an interconnected pore structure in the range of 100-300 μm and a sustained release of Zn ions. More importantly, the Zn-MHMs/Coll scaffolds could enhance the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells. Finally, the bone defect repair results of critical-sized femoral condyle defect rat model demonstrated that the Zn-MHMs/Coll scaffolds could enhance bone regeneration compared with the Coll or MHMs/Coll scaffolds. The results suggest that the biomimetic Zn-MHMs/Coll scaffolds may be of enormous potential in bone repair and regeneration.

  18. A Solid-State NMR Study of Selenium Substitution into Nanocrystalline Hydroxyapatite

    PubMed Central

    Kolmas, Joanna; Kuras, Marzena; Oledzka, Ewa; Sobczak, Marcin

    2015-01-01

    The substitution of selenium oxyanions in the hydroxyapatite structure was examined using multinuclear solid-state resonance spectroscopy (ssNMR). The study was supported by powder X-ray diffractometry (PXRD) and wavelength dispersion X-ray fluorescence (WD-XRF). Samples of pure hydroxyapatite (HA300) and selenate (HA300-1.2SeO4) or selenite (HA300-1.2SeO3) substituted hydroxyapatites were synthesized using the standard wet method and heated at 300 °C to remove loosely bonded water. PXRD data showed that all samples are single-phase, nanocrystalline hydroxyapatite. The incorporation of selenite and selenate ions affected the lattice constants. In selenium-containing samples the concentration of Se was very similar and amounted to 9.55% and 9.64%, for HA300-1.2SeO4 and HA300-1.2SeO3, respectively. PXRD and ssNMR data showed that the selenite doping significantly decreases the crystallite size and crystallinity degree. 31P and 1H NMR experiments demonstrated the developed surface hydrated layer in all samples, especially in HA300-1.2SeO3. 1H NMR studies showed the dehydroxylation of HA during the selenium oxyanions substitution and the existence of hydrogen bonding in structural hydroxyl group channels. 1H→77Se cross polarization NMR experiments indicated that selenites and selenates are located in the crystal lattice and on the crystal surface. PMID:25997001

  19. Comparative study of hydroxyapatite from eggshells and synthetic hydroxyapatite for bone regeneration.

    PubMed

    Lee, Sang-Woon; Kim, Seong-Gon; Balázsi, Csaba; Chae, Weon-Sik; Lee, Hee-Ok

    2012-03-01

    The objective of this study was to evaluate the physical properties of synthetic hydroxyapatite (sHA) and hydroxyapatite from eggshells (eHA) by Fourier-transform infrared (FT-IR) and x-ray diffraction (XRD) and to compare the regenerative ability of the bone using sHA and eHA in a rabbit calvarial defect model. FT-IR and XRD were used to compare the physical properties of sHA and eHA. sHA was purchased from Sigma, and eHA was kindly donated from the Hungarian academy of science. Sixteen New Zealand white rabbits were used for the animal study. After the formation of a bilateral parietal bony defect (diameter 8.0 mm), either sHA or eHA was grafted into the defect. The defect in the control was left unfilled. Bone regeneration was evaluated by histomorphometry at 4 and 8 weeks after the operation. The peak broadening of the XRD experiments were in agreement with scanning electron microscope observation; the sHA had a smaller granule size than the eHA. The eHA had impurities phases of CaO (International Center for Diffraction Data (ICDD) 075-0264) and Ca(OH)(2) (ICDD 072-0156). Total new bone was 17.11 ± 10.24% in the control group, 28.81 ± 12.63% in sHA group, and 25.68 ± 10.89% in eHA group at 4 weeks after the operation. The difference was not statistically significant (P > .05). Total new bone at 8 weeks after the operation was 27.50 ± 10.89% in the control group, 38.62 ± 17.42% in sHA group, and 41.99 ± 8.44% in the eHA group. When comparing the sHA group to the control group, the difference was not statistically significant (P > .05). However, the eHA group was significantly different from the control group (P = .038). When comparing the eHA group to the sHA group, the difference was not statistically significant (P > .05). Both types of HA showed higher bone formation than the unfilled control. However, eHA had significantly higher bone formation than the unfilled control at 8 weeks after operation. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Osteogenesis and Trophic Factor Secretion are Influenced by the Composition of Hydroxyapatite/Poly(Lactide-Co-Glycolide) Composite Scaffolds

    PubMed Central

    He, Jiawei; Genetos, Damian C.

    2010-01-01

    The use of composite biomaterials for bone repair capitalizes on the beneficial aspects of individual materials while tailoring the mechanical properties of the composite. We hypothesized that substrate composition would modulate the osteogenic response and secretion of potent trophic factors by human mesenchymal stem cells (hMSCs). Composite scaffolds were prepared by combining nanosized hydroxyapatite (HA) and microspheres formed of poly(lactic-co-glycolic acid) (PLG) at varying ratios between 0:1 and 5:1. Scaffolds were seeded with hMSCs for culture in osteogenic conditions or subcutaneous implantation into nude rats. Compressive moduli increased with HA content in a near-linear fashion. The osteogenic differentiation of hMSCs increased in a dose-dependent manner as determined by alkaline phosphatase activity and osteopontin secretion after 4 weeks of culture. Further, endogenous secretion of vascular endothelial growth factor was sustained at significantly higher levels over 28 days for hMSCs seeded in 2.5:1 and 5:1 HA:PLG scaffolds. Eight weeks after implantation, scaffolds with higher HA:PLG ratios exhibited greater vascularization and more mineralized tissue. These data demonstrate that the mechanical properties, osteogenic differentiation, as well as the timing and duration of trophic factor secretion by hMSCs can be tailored through controlling the composition of the polymer–bioceramic composite. PMID:19642853

  1. Cell death induced by hydroxyapatite on L929 fibroblast cells.

    PubMed

    Inayat-Hussain, S H; Rajab, N F; Roslie, H; Hussin, A A; Ali, A M; Annuar, B O

    2004-05-01

    Biomaterials intended for end-use application as bone-graft substitutes have to undergo safety evaluation. In this study, we investigated the in vitro cytotoxic effects especially to determine the mode of death of two hydroxyapatite compounds (HA2, HA3) which were synthesized locally. The methods used for cytotoxicity was the standard MTT assay whereas AO/PI staining was performed to determine the mode of cell death in HA treated L929 fibroblasts. Our results demonstrated that both HA2 and HA3 were not significantly cytotoxic as more than 75% cells after 72 hours treatment were viable. Furthermore, we found that the major mode of cell death in HA treated cells was apoptosis. In conclusion, our results demonstrated that these hydroxyapatite compounds are not cytotoxic where the mode of death was primarily via apoptosis.

  2. Biological activity of lactoferrin-functionalized biomimetic hydroxyapatite nanocrystals

    PubMed Central

    Nocerino, Nunzia; Fulgione, Andrea; Iannaccone, Marco; Tomasetta, Laura; Ianniello, Flora; Martora, Francesca; Lelli, Marco; Roveri, Norberto; Capuano, Federico; Capparelli, Rosanna

    2014-01-01

    The emergence of bacterial strains resistant to antibiotics is a general public health problem. Progress in developing new molecules with antimicrobial properties has been made. In this study, we evaluated the biological activity of a hybrid nanocomposite composed of synthetic biomimetic hydroxyapatite surface-functionalized by lactoferrin (LF-HA). We evaluated the antimicrobial, anti-inflammatory, and antioxidant properties of LF-HA and found that the composite was active against both Gram-positive and Gram-negative bacteria, and that it modulated proinflammatory and anti-inflammatory responses and enhanced antioxidant properties as compared with LF alone. These results indicate the possibility of using LF-HA as an antimicrobial system and biomimetic hydroxyapatite as a candidate for innovative biomedical applications. PMID:24623976

  3. Cementless Hydroxyapatite Coated Hip Prostheses

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  4. Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite.

    PubMed

    Carmo, André Boziki Xavier do; Sartoretto, Suelen Cristina; Alves, Adriana Terezinha Neves Novellino; Granjeiro, José Mauro; Miguel, Fúlvio Borges; Calasans-Maia, Jose; Calasans-Maia, Monica Diuana

    2018-01-18

    This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA) and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA) as bone substitute materials. Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group). After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 μm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>0.05). We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039) in both groups. The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes.

  5. Alveolar bone repair with strontium- containing nanostructured carbonated hydroxyapatite

    PubMed Central

    do Carmo, André Boziki Xavier; Sartoretto, Suelen Cristina; Alves, Adriana Terezinha Neves Novellino; Granjeiro, José Mauro; Miguel, Fúlvio Borges; Calasans-Maia, Jose; Calasans-Maia, Monica Diuana

    2018-01-01

    ABSTRACT Objective This study aimed to evaluate bone repair in rat dental sockets after implanting nanostructured carbonated hydroxyapatite/sodium alginate (CHA) and nanostructured carbonated hydroxyapatite/sodium alginate containing 5% strontium microspheres (SrCHA) as bone substitute materials. Methods Twenty male Wistar rats were randomly divided into two experimental groups: CHA and SrCHA (n=5/period/group). After one and 6 weeks of extraction of the right maxillary central incisor and biomaterial implantation, 5 μm bone blocks were obtained for histomorphometric evaluation. The parameters evaluated were remaining biomaterial, loose connective tissue and newly formed bone in a standard area. Statistical analysis was performed by Mann-Withney and and Wilcoxon tests at 95% level of significance. Results The histomorphometric results showed that the microspheres showed similar fragmentation and bio-absorbation (p>0.05). We observed the formation of new bones in both groups during the same experimental periods; however, the new bone formation differed significantly between the weeks 1 and 6 (p=0.0039) in both groups. Conclusion The CHA and SrCHA biomaterials were biocompatible, osteoconductive and bioabsorbable, indicating their great potential for clinical use as bone substitutes. PMID:29364342

  6. Pickering-type water-in-oil-in-water multiple emulsions toward multihollow nanocomposite microspheres.

    PubMed

    Maeda, Hayata; Okada, Masahiro; Fujii, Syuji; Nakamura, Yoshinobu; Furuzono, Tsutomu

    2010-09-07

    Multihollow hydroxyapatite (HAp)/poly(L-lactic acid) (PLLA) nanocomposite microspheres were readily fabricated by solvent evaporation from a "Pickering-type" water-in-(dichloromethane solution of PLLA)-in-water multiple emulsion stabilized with HAp nanoparticles. The multiple emulsion was stabilized with the aid of PLLA molecules used as a wettability modifier for HAp nanoparticles, although HAp nanoparticles did not work solely as particulate emulsifiers for Pickering-type emulsions consisting of pure dichloromethane and water. The interaction between PLLA and HAp nanoparticles at the oil-water interfaces plays a crucial role toward the preparation of stable multiple emulsion and multihollow microspheres.

  7. Wear Behavior of Plasma Spray Deposited and Post Heat-Treated Hydroxyapatite (HA)-Based Composite Coating on Titanium Alloy (Ti-6Al-4V) Substrate

    NASA Astrophysics Data System (ADS)

    Kumari, Renu; Majumdar, Jyotsna Dutta

    2018-04-01

    The present study concerns a detailed evaluation of wear resistance property of plasma spray deposited composite hydroxyapatite (HA)-based (HA-50 wt pct TiO2 and HA-10 wt pct ZrO2) bioactive coatings developed on Ti-6Al-4V substrate and studying the effect of heat treatment on it. Heat treatment of plasma spray deposited samples has been carried out at 650 °C for 2 hours (for HA-50 wt pct TiO2 coating) and at 750 °C for 2 hours (for HA-10 wt pct ZrO2 coating). There is significant deterioration in wear resistance for HA-50 wt pctTiO2 coating and a marginal deterioration in wear resistance for HA-10 wt pct ZrO2 coating in as-sprayed state (as compared to as-received Ti-6Al-4V) which is, however, improved after heat treatment. The coefficient of friction is marginally increased for both HA-50 wt pct TiO2 and HA-10 wt pct ZrO2 coatings in as-sprayed condition as compared to Ti-6Al-4V substrate. However, coefficient of friction is decreased for both HA-50 wt pct TiO2 and HA-10 wt pct ZrO2 coatings after heat-treated condition as compared to Ti-6Al-4V substrate. The maximum improvement in wear resistance property is, however, observed for HA-10 wt pct ZrO2 sample after heat treatment. The mechanism of wear has been investigated.

  8. Bone regeneration in the presence of a synthetic hydroxyapatite/silica oxide-based and a xenogenic hydroxyapatite-based bone substitute material.

    PubMed

    Kruse, A; Jung, R E; Nicholls, F; Zwahlen, R A; Hämmerle, C H F; Weber, F E

    2011-05-01

    A comparison of synthetic hydroxyapatite/silica oxide, xenogenic hydroxyapatite-based bone substitute materials with empty control sites in terms of bone regeneration enhancement in a rabbit calvarial four non-critical-sized defect model. In each of six rabbits, four bicortical calvarial bone defects were generated. The following four treatment modalities were randomly allocated: (1) empty control site, (2) synthetic hydroxyapatite/silica oxide-based (HA/SiO) test granules, (3) xenogenic hydroxyapatite -based granules, (4) synthetic hydroxyapatite/silica oxide -based (HA/SiO) test two granules. The results of the latter granules have not been reported due to their size being three times bigger than the other two granule types. After 4 weeks, the animals were sacrificed and un-decalcified sections were obtained for histological analyses. For statistical analysis, the Kruskal-Wallis test was applied (P<0.05). Histomorphometric analysis showed an average area fraction of newly formed bone of 12.32±10.36% for the empty control, 17.47±6.42% for the xenogenic hydroxyapatite -based granules group, and 21.2±5.32% for the group treated with synthetic hydroxyapatite/silica oxide -based granules. Based on the middle section, newly formed bone bridged the defect to 38.33±37.55% in the empty control group, 54.33±22.12% in the xenogenic hydroxyapatite -based granules group, and to 79±13.31% in the synthetic hydroxyapatite/silica oxide -based granules group. The bone-to-bone substitute contact was 46.38±18.98% for the xenogenic and 59.86±14.92% for the synthetic hydroxyapatite/silica oxide-based granules group. No significant difference in terms of bone formation and defect bridging could be detected between the two bone substitute materials or the empty defect. There is evidence that the synthetic hydroxyapatite/silica oxide granules provide comparable results with a standard xenogenic bovine mineral in terms of bone formation and defect bridging in non-critical size

  9. Porous Hydroxyapatite Scaffold with Three-Dimensional Localized Drug Delivery System Using Biodegradable Microspheres

    DTIC Science & Technology

    2011-03-21

    produced were also labeled with FITC using a modification of a previously described technique [22]. PEI- coated microsphere (30 mg/mL) were mixed with...surface after 4 h of mixing (Fig. 5A), while PEI-coated microspheres were well- dispersed and immobilized onto the HAp surface (Fig. 5B). 3.3. Properties of...Erickson, L. Ren, D. Li, Zeta-potential measurement using the smoluchowski equation and the slope of the current-time relationship in electroosmotic flow

  10. Mechanical strength of [HA/Bioplastic/Sericin] composite part printed by bioprinter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tontowi, Alva Edy, E-mail: alvaedytontowi@ugm.ac.id; Setiawan, Agris

    The aim of this research was to determine the effect of hydroxyapatite (HA) content in printed biocomposite to its mechanical strength. The biocomposite paste was prepared by composing HA, bioplastic and sericin with various ratios of [HA/Bioplastic]: 40/60, 50/50, 60,40 and 70/30. Sericin of 0.3% weight was added to the biocomposite. Mechanical test was conducted to observe tensile (ASTM D 638 type 4) and flexural strength (ASTM D 790). Both type of specimens were fabricated using 3D Printer. Printing process parameter (infill speed, print speed and layer height) were set up as 60 mm/s, 10 mm/s, 0.35 mm, respectively. Resultsmore » showed that biocomposite with [HA/Biplastic]. weight ratio of 60/40(w/w) has an optimum tensile (3.89 ± 1.26 MPa) and flexural strength (2.51 ± 0.45 MPa). Scanning electron microscope observation indicated that microstructure of specimen was influenced by the percentage of the hydroxyapatite. There was no agglomeration of HA particle within the composite.« less

  11. Composition of chitosan-hydroxyapatite-collagen composite scaffold evaluation after simulated body fluid immersion as reconstruction material

    NASA Astrophysics Data System (ADS)

    Verisqa, F.; Triaminingsih, S.; Corputty, J. E. M.

    2017-08-01

    Hydroxyapatite (HA) formation is one of the most important aspects of bone regeneration. Because domestically made chitosan-hydroxyapatite-collagen composite scaffolding from crab shell and bovine bone and tendon has potential as a maxillofacial reconstruction material, the material’s HA-forming ability requires evaluation. The aim of this research is to investigate chitosan-hydroxyapatite-collagen composite scaffold’s potential as a maxillofacial reconstruction material by observing the scaffold’s compositional changes. Scaffold specimens were immersed in 37°C simulated body fluid (SBF) for periods of 2, 4, 6, and 8 days. Scaffold composition was then evaluated by using energy dispersive spectroscopy (EDS). The calcium (Ca) and phosphorus (P) percentages of the scaffold were found to increase following SBF immersion. The high Ca/P ratio (3.82) on the scaffold indicated HA formation. Ion exchange played a significant role in the increased percentages of Ca and P, which led to new HA layer formation. The scaffold’s HA acted as a nucleation site of Ca and P from the SBF, with collagen and chitosan as the scaffold’s matrix. Chitosan-hydroxyapatite-collagen composite scaffold shows potential as a maxillofacial reconstruction material, since its composition favors HA formation.

  12. New Coll-HA/BT composite materials for hard tissue engineering.

    PubMed

    Zanfir, Andrei Vlad; Voicu, Georgeta; Busuioc, Cristina; Jinga, Sorin Ion; Albu, Madalina Georgiana; Iordache, Florin

    2016-05-01

    The integration of ceramic powders in composite materials for bone scaffolds can improve the osseointegration process. This work was aimed to the synthesis and characterization of new collagen-hydroxyapatite/barium titanate (Coll-HA/BT) composite materials starting from barium titanate (BT) nanopowder, hydroxyapatite (HA) nanopowder and collagen (Coll) gel. BT nanopowder was produced by combining two wet-chemical approaches, sol-gel and hydrothermal methods. The resulting materials were characterized in terms of phase composition and microstructure by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. Moreover, the biocompatibility and bioactivity of the composite materials were assessed by in vitro tests. The synthesized BT particles exhibit an average size of around 35 nm and a spherical morphology, with a pseudo-cubic or tetragonal symmetry. The diffraction spectra of Coll-HA and Coll-HA/BT composite materials indicate a pronounced interaction between Col and the mineral phases, meaning a good mineralization of Col fibres. As well, the in vitro tests highlight excellent osteoinductive properties for all biological samples, especially for Coll-HA/BT composite materials, fact that can be attributed to the ferromagnetic properties of BT. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Microfluidic vascularized bone tissue model with hydroxyapatite-incorporated extracellular matrix.

    PubMed

    Jusoh, Norhana; Oh, Soojung; Kim, Sudong; Kim, Jangho; Jeon, Noo Li

    2015-10-21

    Current in vitro systems mimicking bone tissues fail to fully integrate the three-dimensional (3D) microvasculature and bone tissue microenvironments, decreasing their similarity to in vivo conditions. Here, we propose 3D microvascular networks in a hydroxyapatite (HA)-incorporated extracellular matrix (ECM) for designing and manipulating a vascularized bone tissue model in a microfluidic device. Incorporation of HA of various concentrations resulted in ECM with varying mechanical properties. Sprouting angiogenesis was affected by mechanically modulated HA-extracellular matrix interactions, generating a model of vascularized bone microenvironment. Using this platform, we observed that hydroxyapatite enhanced angiogenic properties such as sprout length, sprouting speed, sprout number, and lumen diameter. This new platform integrates fibrin ECM with the synthetic bone mineral HA to provide in vivo-like microenvironments for bone vessel sprouting.

  14. Three-dimensional printed bone scaffolds: The role of nano/micro-hydroxyapatite particles on the adhesion and differentiation of human mesenchymal stem cells.

    PubMed

    Domingos, Marco; Gloria, Antonio; Coelho, Jorge; Bartolo, Paulo; Ciurana, Joaquim

    2017-06-01

    Bone tissue engineering is strongly dependent on the use of three-dimensional scaffolds that can act as templates to accommodate cells and support tissue ingrowth. Despite its wide application in tissue engineering research, polycaprolactone presents a very limited ability to induce adhesion, proliferation and osteogenic cell differentiation. To overcome some of these limitations, different calcium phosphates, such as hydroxyapatite and tricalcium phosphate, have been employed with relative success. This work investigates the influence of nano-hydroxyapatite and micro-hydroxyapatite (nHA and mHA, respectively) particles on the in vitro biomechanical performance of polycaprolactone/hydroxyapatite scaffolds. Morphological analysis performed with scanning electron microscopy allowed us to confirm the production of polycaprolactone/hydroxyapatite constructs with square interconnected pores of approximately 350 µm and to assess the distribution of hydroxyapatite particles within the polymer matrix. Compression mechanical tests showed an increase in polycaprolactone compressive modulus ( E) from 105.5 ± 11.2 to 138.8 ± 12.9 MPa (PCL_nHA) and 217.2 ± 21.8 MPa (PCL_mHA). In comparison to PCL_mHA scaffolds, the addition of nano-hydroxyapatite enhanced the adhesion and viability of human mesenchymal stem cells as confirmed by Alamar Blue assay. In addition, after 14 days of incubation, PCL_nHA scaffolds showed higher levels of alkaline phosphatase activity compared to polycaprolactone or PCL_mHA structures.

  15. In Vitro and In Vivo Evaluations of Nano-Hydroxyapatite/Polyamide 66/Glass Fibre (n-HA/PA66/GF) as a Novel Bioactive Bone Screw

    PubMed Central

    Su, Bao; Peng, Xiaohua; Jiang, Dianming; Wu, Jun; Qiao, Bo; Li, Weichao; Qi, Xiaotong

    2013-01-01

    In this study, we prepared nano-hydroxyapatite/polyamide 66/glass fibre (n-HA/PA66/GF) bioactive bone screws. The microstructure, morphology and coating of the screws were characterised, and the adhesion, proliferation and viability of MC3T3-E1 cells on n-HA/PA66/GF scaffolds were determined using scanning electron microscope, CCK-8 assays and cellular immunofluorescence analysis. The results confirmed that n-HA/PA66/GF scaffolds were biocompatible and had no negative effect on MC3T3-E1 cells in vitro. To investigate the in vivo biocompatibility, internal fixation properties and osteogenesis of the bioactive screws, both n-HA/PA66/GF screws and metallic screws were used to repair intercondylar femur fractures in dogs. General photography, CT examination, micro-CT examination, histological staining and biomechanical assays were performed at 4, 8, 12 and 24 weeks after operation. The n-HA/PA66/GF screws exhibited good biocompatibility, high mechanical strength and extensive osteogenesis in the host bone. Moreover, 24 weeks after implantation, the maximum push-out load of the bioactive screws was greater than that of the metallic screws. As shown by their good cytocompatibility, excellent biomechanical strength and fast formation and ingrowth of new bone, n-HA/PA66/GF screws are thus suitable for orthopaedic clinical applications. PMID:23861888

  16. Microstructural disintegration in dense hydroxyapatite and hydroxyapatite-coated metal implants

    NASA Astrophysics Data System (ADS)

    Seo, Dong Seok; Lee, Jong Kook

    2007-08-01

    Hydroxyapatite (HA) has been widely used as a coating for orthopedic metal implants. An important concern regarding HA coating is its degradation of the biological milieu. In this study, the microstructure of a retrieved HA-coated acetabular cup implanted for four years after total hip arthroplasty (THA) was investigated by field emission scanning electron microscopy. In order to understand the underlying mechanism, of degradation and exfoliation of the HA coating, degradation of phase-pure and dense HA ceramics was also observed by in vitro and in vivo testing. The surface morphology and fracture surfaces of HA ceramics revealed that the dissolution starting at the surface extended inwards resulting in particle loosening and microstructural-level degradation. The dissolution features of HA ceramics were similar to the case of HA coating. It was found that extensive dissolution of the coating occurred and most of the coating disappeared. The majority of the remaining graints were fractured by the intergranular mode, suggesting that grain boundaries should be predominantly dissolved. These observations may explain the mechanism through which the biological stability of the HA coated layer becomes unexpectedly poor.

  17. Monodisperse selenium-substituted hydroxyapatite: Controllable synthesis and biocompatibility.

    PubMed

    Sun, Jianpeng; Zheng, Xiaoyan; Li, Hui; Fan, Daidi; Song, Zhanping; Ma, Haixia; Hua, Xiufu; Hui, Junfeng

    2017-04-01

    Hydroxyapatite (HA) is the major inorganic component of natural bone tissue. As an essential trace element, selenium involves in antioxidation and anticancer of human body. So far, ion-doped hydroxyapatites (HAs) are widely investigated owing to their great applications in field of biomaterial, biological labeling. In this paper, series of monodisperse HA doped with SeO 3 2- (SeHA) was successfully synthesized based on the liquid-solid-solution (LSS) strategy. The obtained samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive spectrometer (EDS). The results indicated that the SeO 3 2- doping level of the Se/(P+Se) molar ratio of 0-0.4 can be requisitely controlled, and the morphology of SeHA nanoparticles varied from nanorods to nanoneedles with increasing Se/(P+Se) molar ratio. Significantly, the as-synthesized SeHA nanocrystals exhibit a low cytotoxicity for osteoblastic cells, showing exciting potentials for application in artificial scaffold materials inhibiting of tumor growth in bone. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Hydroxyapatite formation from cuttlefish bones: kinetics.

    PubMed

    Ivankovic, H; Tkalcec, E; Orlic, S; Ferrer, G Gallego; Schauperl, Z

    2010-10-01

    Highly porous hydroxyapatite (Ca(10)(PO(4))(6)·(OH)(2), HA) was prepared through hydrothermal transformation of aragonitic cuttlefish bones (Sepia officinalis L. Adriatic Sea) in the temperature range from 140 to 220°C for 20 min to 48 h. The phase composition of converted hydroxyapatite was examined by quantitative X-ray diffraction (XRD) using Rietveld structure refinement and Fourier transform infrared spectroscopy (FTIR). Johnson-Mehl-Avrami (JMA) approach was used to follow the kinetics and mechanism of transformation. Diffusion controlled one dimensional growth of HA, predominantly along the a-axis, could be defined. FTIR spectroscopy determined B-type substitutions of CO(3) (2-) groups. The morphology and microstructure of converted HA was examined by scanning electron microscopy. The general architecture of cuttlefish bones was preserved after hydrothermal treatment and the cuttlefish bones retained its form with the same channel size (~80 × 300 μm). The formation of dandelion-like HA spheres with diameter from 3 to 8 μm were observed on the surface of lamellae, which further transformed into various radially oriented nanoplates and nanorods with an average diameter of about 200-300 nm and an average length of about 8-10 μm.

  19. Preparation and characterization of collagen-hydroxyapatite/pectin composite.

    PubMed

    Wenpo, Feng; Gaofeng, Liang; Shuying, Feng; Yuanming, Qi; Keyong, Tang

    2015-03-01

    Pectin, a kind of plant polysaccharide, was introduced into collagen-hydroxyapatite composite system, and prepared collagen-hydroxyapatite/pectin (Col-HA/pectin) composite in situ. The structure of the composite was investigated by XRD, SEM, and FT-IR. The mechanical properties, water absorption, enzyme degradation, and cytotoxicity of the composite were investigated as well. The results show that the inorganic substance in the composite materials is hydroxyapatite in relatively low crystallinity. A new interface appeared by the interaction among hydroxyapatite and collagen-pectin, and formed smooth fine particles. The mechanical properties, water absorption, enzyme degradation, and cytotoxicity indicate a potential use in bone replacement for the new composite. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Influence of sodium fluoride on the synthesis of hydroxyapatite by gel method

    NASA Astrophysics Data System (ADS)

    Kanchana, P.; Sekar, C.

    2010-03-01

    Hydroxyapatite (HA) is a good candidate for bone substitutes due to its chemical and structural similarity to bone mineral. Hydroxyapatite has been grown by the gel method using sodium fluoride (NaF) as additive. The growth was carried out at room temperature under the physiological pH of 7.4. The addition of NaF has significantly reduced growth rate and the yield was much less when compared to pure system. The samples of pure and fluoride doped HA were sintered at 600, 900 and 1200 °C in ambient atmosphere. Scanning electron microscopy (SEM), powder X-ray diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared spectroscopy (FTIR) were adopted to investigate the influence of NaF on the morphology, crystallinity, stability and phase purity of HA. EDAX and FTIR studies confirm that the fluoride is doped into the hydroxyapatite. Powder XRD and TGA results suggested that the incorporation of fluorine into the HA matrix improves the phase formation and crystallinity. SEM studies show that the microstructural morphology of HA changes from the fibers for pure to granular structure for the fluoride doped.

  1. Assessment of tricalcium phosphate/collagen (TCP/collagene)nanocomposite scaffold compared with hydroxyapatite (HA) on healing of segmental femur bone defect in rabbits.

    PubMed

    Mohseni, Mahmoud; Jahandideh, Alireza; Abedi, Gholamreza; Akbarzadeh, Abolfazl; Hesaraki, Saeed

    2018-03-01

    Bone regeneration is an important objective in clinical practice and has been used for different applications. The aim of this study was to evaluate the effectiveness of nanocomposite tricalcium phosphate (TCP)/collagen scaffolds combined with hydroxyapatite scaffold for bone healing in surgery of femoral defects in rabbits. In this study, 45 mature male New Zealand white rabbits between 6 and 8 months old and weighting between 3 and 3.5 kg were examined. Rabbits were divided into three groups. Surgical procedures were performed after intramuscular injection of Ketamine 10% (ketamine hydrochloride, 50 mg/kg) and Rompun 5% (xylazine, 5 mg/kg). Then an approximately 6 mm diameter-5 mm cylinder bone defect was created in the femur of one of the hind limbs. After inducing the surgical wound, all rabbits were coloured and randomly divided into three experimental groups of 15 animals each. Group 1 received pure medical nanocomposite TCP/collagen granules, group 2 received hydroxyapatite, and third group was a control group which received no treatment. Histopathological evaluation was performed on days 15, 30, and 45 after surgery. On days 15, 30, and 45 after surgery, the quantity and the velocity of stages of bone formation at the healing site in nanocomposite TCP/collagen group were better than HA and control groups and the quantity of newly formed lamellar bone at the healing site in nanocomposite TCP/collagen group were better than onward compared with HA and control groups. In conclusion, it seems that TCP/collagen nanocomposite has a significant role in the reconstruction of bone defects and can be used as scaffold in bone fractures.

  2. Effect of Hydroxyapatite on Bone Integration in a Rabbit Tibial Defect Model

    PubMed Central

    Sohn, Sung-Keun; Kim, Kyung-Taek; Kim, Chul-Hong; Ahn, Hee-Bae; Rho, Mee-Sook; Jeong, Min-Ho; Sun, Sang-Kyu

    2010-01-01

    Background The aim of the present study was to prepare hydroxyapatite (HA) and then characterize its effect on bone integration in a rabbit tibial defect model. The bone formation with different designs of HA was compared and the bony integration of several graft materials was investigated qualitatively by radiologic and histologic study. Methods Ten rabbits were included in this study; two holes were drilled bilaterally across the near cortex and the four holes in each rabbit were divided into four treatment groups (HAP, hydroxyapatite powder; HAC, hydroxyapatite cylinder; HA/TCP, hydroxyapatite/tri-calcium phosphate cylinder, and titanium cylinder). The volume of bone ingrowth and the change of bone mineral density were statistically calculated by computed tomography five times for each treatment group at 0, 2, 4, 6, and 8 weeks after grafting. Histologic analysis was performed at 8 weeks after grafting. Results The HAP group showed the most pronounced effect on the bone ingrowth surface area, which seen at 4, 6, and 8 weeks after graft (p < 0.05). On comparing the change of bone mineral density the bone ingrowth surface area among the 4 groups, there were no statistically significant differences among the groups found for any period (p > 0.05). On histological examination, the HAP group revealed well-recovered cortical bone, but the bone was irregularly thickened and haphazardly admixed with powder. The HAC group showed similar histological features to those of the HA/TCP group; the cortical surface of the newly developed bone was smooth and the bone matrix on the surface of the cylinder was regularly arranged. Conclusions We concluded that both the hydroxyapatite powder and cylinder models investigated in our study may be suitable as a bone substitute in the rabbit tibial defect model, but their characteristic properties are quite different. In contrast to hydroxyapatite powder, which showed better results for the bone ingrowth surface, the hydroxyapatite

  3. New bioactive bone-like microspheres with intrinsic magnetic properties obtained by bio-inspired mineralisation process.

    PubMed

    Fernandes Patrício, Tatiana Marisa; Panseri, Silvia; Sandri, Monica; Tampieri, Anna; Sprio, Simone

    2017-08-01

    A bio-inspired mineralisation process was investigated and applied to develop novel hybrid magnetic materials by heterogeneous nucleation of Fe 2+ /Fe 3+ -doped hydroxyapatite nanocrystals onto a biopolymeric matrix made of a Type I collagen-based recombinant peptide (RCP). The effect of the synthesis temperature on the phase composition, crystallinity and magnetic properties of the nucleated inorganic phase was studied. The as-obtained magnetic materials were then engineered, by using a water-in-oil emulsification process, into hybrid magnetic microspheres, which were stabilized by de-hydrothermal treatment yielding cross-linking of the macromolecular matrix. Thorough investigation of the physicochemical, morphological and biological properties of the new hybrid microspheres, as induced by the presence of the inorganic nanophase and controlled iron substitution into hydroxyapatite lattice, revealed bone-like composition, good cytocompatibility, designed shape and size, and tailored magnetization. Such features are interesting and promising for application as new biomaterials with ability of remote activation and control by using external magnetic fields, for smart and personalized applications in medicine, particularly in bone tissue regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Effect of modification substrate on the microstructure of hydroxyapatite coating

    NASA Astrophysics Data System (ADS)

    Realpe-Jaramillo, J.; Morales-Morales, J. A.; González-Sánchez, J. A.; Cabanzo, R.; Mejía-Ospino, E.; Rodríguez-Pereira, J.

    2017-01-01

    Bioactive hydroxyapatite (HA) coatings were fabricated by a precipitation, sol-gel and dip-coating method. The effects of the aging time and the base used to adjust pH and substrate materials on the phases and microstructures of HA coatings were studied by field emission scanning electron microscopy FESEM, energy dispersive spectroscopy EDS, X-ray photoelectron spectroscopy XPS, and the vibrations of the phosphate groups were determined by Raman spectroscopy. The results showed that all the films were composed of the phases of TiO2 and HA. With coated titanium substrate with TiO2, the crystallinity of the HA coating increases, the structure became more compact and the Ca/P ratio increased because of the loss of P in the films. The addition of sodium hydroxide (adjusting the pH level to about 10) can increase the HA content in the coating. XPS and EDS results for steel substrate and titanium showed poor calcium content as obtained with a Ca/P ratio of 1.38 and 1.58, respectively, composition is similar to that of natural apatite. However, spectroscopic results suggest the presence of a mixture of hydroxyapatite and octacalcium phosphate. The different substrate materials have a high influence on the microstructure of the separated double films. However, hydroxyapatite nanopowders coatings were obtained using a simple method, with potential biomedical applications.

  5. Biodegradable composites with aligned hydroxyapatite nanoneedles.

    PubMed

    Sun, Shih-Po; Wei, Mei; Olson, James R; Shaw, Montgomery T

    2012-10-01

    We prepared an anisotropic bone graft composite to mimic the hierarchical structure of the natural bone in which aligned hydroxyapatite (HA) nanocrystals deposit along collagen fibers. To approach the modulus and strength of the bone, we incorporated synthesized HA nanoneedles and melt drawn poly(L-lactic acid) fibers in our composite as reinforcing components. Their preferred orientation was induced via a modified pultrusion process. The HA orientation distribution was examined using wide angle X-ray diffraction. Micromechanical Halpin-Tsai model predictions considering the amount, shape, and orientation distribution of HA were compared, favorably, with the experimental observations. Copyright © 2012 Wiley Periodicals, Inc.

  6. Biomimetic Bone-like Hydroxyapatite by Mineralization on Supramolecular Porous Fiber Networks.

    PubMed

    Li, Bo; Kan, Lei; Zhang, Xinyue; Li, Jie; Li, Ruiting; Gui, Qinyuan; Qiu, Dengli; He, Fei; Ma, Ning; Wang, Yapei; Wei, Hao

    2017-08-29

    Hydroxyapatite (HA), the main inorganic component of bone tissue, is mineralized with collagen fibril scaffolds during bone formation. Inspired by the process, a self-assembled porous network architecture was designed and synthesized by using the 2-ureido-4[1H]-pyrimidone (UPy) modified glycerol molecule UPy-Gly, which was further utilized as a template for biomimetic mineralization. When incubated in simulated body fluid (SBF), the HA nucleus first formed in the holes of the template by the induction of hydroxyls on the surface, grew along the nanofibers, and fused with the template to fabricate hydroxyapatite composites (UPy-Gly/HA). Transmission electron microscopic observation demonstrates that the mineral clusters are accumulated by lamella-like nano hydroxyapatite and the elasticity modulus measured by atomic force microscopy is about 5.5 GPa, which is quite close to the natural cancellous bone tissue of human both in structure and in mechanical properties. The Cell Counting Kit 8 (CCK-8) assay of UPy-Gly and UPy-Gly/HA shows noncytotoxicity to mouse fibroblast L-929 cells. This bioinspired composite will be a promising material for potential use in bone tissue implantation and regeneration engineering.

  7. Zinc and Carbonate Co-Substituted Nano-Hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Girija, E. K.; Kumar, G. Suresh; Thamizhavel, A.

    2011-07-01

    Synthesis of Zn or CO32- substituted nano-hydroxyapatite (HA) and its physico-chemical properties have been well documented. However, the effects of the simultaneous substitution of Zn and CO32- in nano-HA have not been reported. In the present study, Zn and CO32- substitutions in nano HA independently and concurrently have been done by wet precipitation method and characterized by XRD and FT-IR for its phase purity and chemical homogeneity. Further modulations of the bioactivity and thermal stability of HA due to the substitutions have been studied.

  8. Observations on the microvasculature of bone defects filled with biodegradable nanoparticulate hydroxyapatite.

    PubMed

    Kilian, Olaf; Wenisch, Sabine; Karnati, Srikanth; Baumgart-Vogt, Eveline; Hild, Anne; Fuhrmann, Rosemarie; Jonuleit, Tarja; Dingeldein, Elvira; Schnettler, Reinhard; Franke, Ralf-Peter

    2008-01-01

    The microvascularization of metaphyseal bone defects filled with nanoparticulate, biodegradable hydroxyapatite biomaterial with and without platelet factors enrichment was investigated in a minipig model. Results from morphological analysis and PECAM-1 immunohistochemistry showed the formation of new blood vessels into the bone defects by sprouting and intussusception of pre-existing ones. However, no significant differences were observed in the microvascularization of the different biomaterials applied (pure versus platelet factors-enriched hydroxyapatite), concerning the number of vessels and their morphological structure at day 20 after operation. The appearance of VEGFR-2 positive endothelial progenitor cells in the connective tissue between hydroxyapatite particles was also found to be independent from platelet factors enrichment of the hydroxyapatite bone substitute. In both groups formation of lymphatic vessels was detected with a podoplanin antibody. No differences were noted between HA/PLF- and HA/PLF+ implants with respect to the podoplanin expression level, the staining pattern or number of lymphatic vessels. In conclusion, the present study demonstrates different mechanisms of blood and lymphatic vessel formation in hydroxyapatite implants in minipigs.

  9. Inflammatory cell response to ultra-thin amorphous and crystalline hydroxyapatite surfaces.

    PubMed

    Rydén, Louise; Omar, Omar; Johansson, Anna; Jimbo, Ryo; Palmquist, Anders; Thomsen, Peter

    2017-01-01

    It has been suggested that surface modification with a thin hydroxyapatite (HA) coating enhances the osseointegration of titanium implants. However, there is insufficient information about the biological processes involved in the HA-induced response. This study aimed to investigate the inflammatory cell response to titanium implants with either amorphous or crystalline thin HA. Human mononuclear cells were cultured on titanium discs with a machined surface or with a thin, 0.1 μm, amorphous or crystalline HA coating. Cells were cultured for 24 and 96 h, with and without lipopolysaccharide (LPS) stimulation. The surfaces were characterized with respect to chemistry, phase composition, wettability and topography. Biological analyses included the percentage of implant-adherent cells and the secretion of pro-inflammatory cytokine (TNF-α) and growth factors (BMP-2 and TGF-β1). Crystalline HA revealed a smooth surface, whereas the amorphous HA displayed a porous structure, at nano-scale, and a hydrophobic surface. Higher TNF-α secretion and a higher ratio of adherent cells were demonstrated for the amorphous HA compared with the crystalline HA. TGF-β1 secretion was detected in all groups, but without any difference. No BMP-2 secretion was detected in any of the groups. The addition of LPS resulted in a significant increase in TNF-α in all groups, whereas TGF-β1 was not affected. Taken together, the results show that thin HA coatings with similar micro-roughness but a different phase composition, nano-scale roughness and wettability are associated with different monocyte responses. In the absence of strong inflammatory stimuli, crystalline hydroxyapatite elicits a lower inflammatory response compared with amorphous hydroxyapatite.

  10. The effect of the type of HA on the degradation of PLGA/HA composites.

    PubMed

    Naik, Ashutosh; Shepherd, David V; Shepherd, Jennifer H; Best, Serena M; Cameron, Ruth E

    2017-01-01

    The aim of this study is to explore the importance of the potentially competing effects of buffering effects of the calcium phosphate filler and particle-mediated water sorption on the degradation products of poly(d,l lactide-co-glycolide (50:50))(PLGA)/hydroxyapatite(HA) composites. Further the influence of type of HA on the mechanical properties of the composites was investigated. Phase pure HA was synthesised via a reaction between aqueous solutions of calcium hydroxide and orthophosphoric acid. The powder produced was either used as produced (uncalcined) or calcined in air or calcined in a humidified argon atmosphere. An in-vitro degradation study was carried out in phosphate buffered saline (PBS). The results obtained indicated that the degradation rate of the composite might be better understood if both the buffering effects and the rate of water sorption by the composites are considered. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Carbon-centered radicals in γ-irradiated bone substituting biomaterials based on hydroxyapatite.

    PubMed

    Sadlo, Jaroslaw; Strzelczak, Grazyna; Lewandowska-Szumiel, Malgorzata; Sterniczuk, Marcin; Pajchel, Lukasz; Michalik, Jacek

    2012-09-01

    Gamma irradiated synthetic hydroxyapatite, bone substituting materials NanoBone(®) and HA Biocer were examined using EPR spectroscopy and compared with powdered human compact bone. In every case, radiation-induced carbon centered radicals were recorded, but their molecular structures and concentrations differed. In compact bone and synthetic hydroxyapatite the main signal assigned to the CO(2) (-) anion radical was stable, whereas the signal due to the CO(3) (3-) radical dominated in NanoBone(®) and HA Biocer just after irradiation. However, after a few days of storage of these samples, also a CO(2) (-) signal was recorded. The EPR study of irradiated compact bone and the synthetic graft materials suggest that their microscopic structures are different. In FT-IR spectra of NanoBone(®), HA Biocer and synthetic hydroxyapatite the HPO(4) (2-) and CO(3) (2-) in B-site groups are detected, whereas in compact bone signals due to collagen dominate.

  12. The electrolysis time on electrosynthesis of hydroxyapatite with bipolar membrane

    NASA Astrophysics Data System (ADS)

    Nur, Adrian; Jumari, Arif; Budiman, Anatta Wahyu; Puspitaningtyas, Stella Febianti; Cahyaningrum, Suci; Nazriati, Nazriati; Fajaroh, Fauziatul

    2018-02-01

    The electrochemical method with bipolar membrane has been successfully used for the synthesis of hydroxyapatite. In this work, we have developed 2 chambers electrolysis system separated by a bipolar membrane. The membrane was used to separate cations (H+ ions produced by the oxidation of water at the anode) and anions (OH- ions produced by the reduction of water at the cathode). With this system, we have designed that OH- ions still stay in the anions chamber because OH- ions was very substantial in the hydroxyapatite particles formation. The aim of this paper was to compare the electrolysis time on electrosynthesis of hydroxyapatite with and without the bipolar membrane. The electrosynthesis was performed at 500 mA/cm2 for 0.5 to 2 hours at room temperature and under ultrasonic cleaner to void agglomeration with and without the bipolar membrane. The electrosynthesis of hydroxyapatite with the bipolar membrane more effective than without the bipolar membrane. The hydroxyapatite has been appeared at 0.5 h of the electrolysis time with the bipolar membrane (at the cathode chamber) while it hasn't been seen without the bipolar membrane. The bipolar membrane prevents OH- ions migrate to the cation chamber. The formation of HA becomes more effective because OH- ions just formed HA particle.

  13. Mimix hydroxyapatite cement use in the reconstruction of the craniofacial skeleton.

    PubMed

    Mann, Robert J; Blount, Andrew L; Neaman, Keith C; Korepta, Lindsey

    2011-11-01

    Reconstruction of the craniofacial skeleton has undergone a significant evolution during the past century. Initially, the use of autogenous bone grafts from various sites was the criterion standard. However, owing to donor site morbidity and lack of sufficient bone for large defects, surgeons have relied on various bone substitutes. Hydroxyapatite (HA) has served as an alternative to autogenous grafts, but questions regarding biocompatibility, risk of infection, and slow set times have hampered its acceptance. This article serves as a review of a single surgeon's experience using HA in the craniofacial skeleton. Eighteen patients receiving HA between March 2000 and November 2006 were observed. Sixteen underwent recontouring of skull-based bone defects, and 2 underwent recontouring for nasal and alveolar defects. The mean amount of HA used in each patient was 30.2 g. For large contour irregularities, the maximum thickness of HA used was 8 mm. The size of bone defects ameliorated averaged 4.8 cm(2). Complications occurred in 3 (16.7%) of 18 patients and included scalp hematoma and superficial cellulitis. In addition, 1 patient developed a facial abscess after placement along the alveolar floor, which necessitated removal. Hydroxyapatite represents a viable alternative to autogenous bone grafts when used in the correct manner. Hydroxyapatite should be used only for smaller defects or used in conjunction with absorbable plates when attempting to fill larger defects. Use of HA for nasal piriform augmentation or alveolar bone grafting should not be considered owing to problems with late infections.

  14. Inhibition of hydroxyapatite growth by casein, a potential salivary phosphoprotein homologue.

    PubMed

    Romero, Maria J R H; Nakashima, Syozi; Nikaido, Toru; Ichinose, Shizuko; Sadr, Alireza; Tagami, Junji

    2015-08-01

    Salivary phosphoproteins are essential in tooth mineral regulation but are often overlooked in vitro. This study aimed to evaluate the effect of casein, as a salivary phosphoprotein homologue, on the deposition and growth of hydroxyapatite (HA) on tooth surfaces. Hydroxyapatite growth was quantified using seeded crystal systems. Artificial saliva (AS) containing HA powder and 0, 10, 20, 50, or 100 μg ml(-1) of casein, or 100 μg ml(-1) of dephosphorylated casein (Dcasein), was incubated for 0-8 h at 37°C, pH 7.2. Calcium concentrations were measured using atomic absorption spectroscopy (AAS). Surface precipitation of HA on bovine enamel and dentine blocks, incubated in similar conditions for 7 d, was examined using field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) with selected area electron diffraction (SAED). Casein adsorption was assessed using modified Lowry assays and zeta-potential measurements. The AAS results revealed a concentration-dependent inhibition of calcium consumption. Hydroxyapatite precipitation occurred when no casein was present, whereas precipitation of HA was apparently completely inhibited in casein-containing groups. Adsorption data demonstrated increasingly negative zeta-potential with increased casein concentration and an affinity constant similar to proline-rich proteins with Langmuir modelling. Casein inhibited the deposition and growth of HA primarily through the binding of esterized phosphate to HA active sites, indicating its potential as a mineral-regulating salivary phosphoprotein homologue in vitro. © 2015 Eur J Oral Sci.

  15. Hydroxyapatite substituted by transition metals: experiment and theory.

    PubMed

    Zilm, M E; Chen, L; Sharma, V; McDannald, A; Jain, M; Ramprasad, R; Wei, M

    2016-06-28

    Bioceramics are versatile materials for hard tissue engineering. Hydroxyapatite (HA) is a widely studied biomaterial for bone grafting and tissue engineering applications. The crystal structure of HA allows for a wide range of substitutions, which allows for tailoring materials properties. Transition metals and lanthanides are of interest since substitution in HA can result in magnetic properties. In this study, experimental results were compared to theoretical calculations of HA substituted with a transition metal. Calculation of a 10 atomic percent substitution of a transition metal ion Mn(2+), Fe(2+), and Co(2+) substituted HA samples lead to magnetic moments of 5, 4, and 3 Bohr magnetons, respectively. Hydroxyapatite substituted by transition metals (MHA) was fabricated through an ion exchange procedure and characterized with X-ray diffraction, Fourier transform infra-red spectroscopy (FTIR), X-ray photoelectron spectroscopy, and vibrating sample magnetometer, and results were compared to theoretical calculations. All the substitutions resulted in phase-pure M(2+)HA with lattice parameters and FTIR spectra in good agreement with calculations. Magnetic measurements revealed that the substitution of Mn(2+) has the greatest effect on the magnetic properties of HA followed by the substitution of Fe(2+) and then Co(2+). The present work underlines the power of synergistic theoretical-experimental work in guiding the rational design of materials.

  16. Novel selenium-doped hydroxyapatite coatings for biomedical applications.

    PubMed

    Rodríguez-Valencia, C; López-Álvarez, M; Cochón-Cores, B; Pereiro, I; Serra, J; González, P

    2013-03-01

    Nowadays there is a short-term need of investigating in orthopedic implants with a greater functionality, including an improved osseointegration and also antibacterial properties. The coating of metallic implants with hydroxyapatite (HA) remains to be the main proposal, but superior quality HA coatings with compositions closer to natural bone apatites, including carbonates, trace elements are required. Selenium is an essential nutrient in biological tissues and, at the same time, it also presents antibacterial properties. A pioneering study on the fabrication of selenium-doped carbonated hydroxyapatite (iHA:Se) coatings by Pulsed Laser Deposition (PLD) is presented. Different proportions of selenium were incorporated to obtain the iHA:Se coatings. Their physicochemical characterization, performed by SEM/EDS, FTIR, FT-Raman, Interferometric Profilometry and XPS, revealed typical columnar growth of HA in globular aggregates and the efficient incorporation of selenium into the HA coatings by the, most probably, substitution of SeO(3)(2-) groups in the CO(3)(2-) sites. Biological evaluation illustrated the absence of cytotoxicity when an amount of 0.6 at.% of Se was added to the iHA:Se coatings and excellent proliferation of the MC3T3-E1 preosteoblasts. Antibacterial properties were also proved with the inhibition of P. aeruginosa and S. aureus from establishing bacterial biofilms. Copyright © 2012 Wiley Periodicals, Inc.

  17. Surface modification of hydroxyapatite nanoparticles by poly( L-phenylalanine) via ROP of L-phenylalanine N-carboxyanhydride (Pha-NCA)

    NASA Astrophysics Data System (ADS)

    Dai, Yanfeng; Xu, Min; Wei, Junchao; Zhang, Haobin; Chen, Yiwang

    2012-01-01

    The surface of hydroxyapatite nanoparticles was modified by poly(L-phenylalanine) via the ring opening polymerization (ROP) of L-phenylalanine N-carboxyanhydride. The preparation procedure was monitored by Fourier transform infrared spectroscopy (FTIR), and the modified hydroxyapatite was characterized by thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). The results showed that the surface grafting amounts of poly(L-phenylalanine) on HA ranging from 20.26% to 38.92% can be achieved by tuning the reaction condition. The XRD patterns demonstrated that the crystalline structure of the modified hydroxyapatite was nearly the same with that of HA, implying that the ROP was an efficient surface modification method. The MTT assay proved that the biocompatibility of modified HA was very good, which showed the potential application of modified HA in bone tissue engineering.

  18. Hydroxyapatite-chitosan based bioactive hybrid biomaterials with improved mechanical strength

    NASA Astrophysics Data System (ADS)

    Zima, A.

    2018-03-01

    Composites consisting of hydroxyapatite (HA) and chitosan (CTS) have recently been intensively studied. In this work, a novel inorganic-organic (I/O) HA/CTS materials in the form of granules were prepared through a simple solution-based chemical method. During the synthesis of these hybrids, the electrostatic complexes between positively charged, protonated amine groups of chitosan and the negative phosphate species (HPO42 - and H2PO4-) were formed. Our biocomposites belong to the class I of hybrids, which was confirmed by FTIR studies. XRD analysis revealed that the obtained materials consisted of hydroxyapatite as the only crystalline phase. Homogeneous dispersion of the components in HA/CTS composites was confirmed. The use of 17 wt% and 23 wt% of chitosan resulted in approximately 12-fold and 16-fold increase in the compressive strength of HA/CTS as compared to the non-modified HA material. During incubation of the studied materials in SBF, pH of the solution remained close to the physiological one. Formation of apatite layer on their surfaces indicated bioactive nature of the developed biomaterials.

  19. Bio resorbability of the modified hydroxyapatite in Tris-HCL buffer

    NASA Astrophysics Data System (ADS)

    Golovanova, O. A.; Izmailov, R. R.; Ghyngazov, S. A.

    2016-02-01

    The solubility of carbonated hydroxyapatite powders and granulated carbonated hydroxyapatite produced from the synovial biofluid model solution has been studied. The kinetic characteristics of dissolution were determined. It was found that the solubility of carbonated hydroxyapatite is higher as compared to that of hydroxyapatite. The impact of the organic matrix on the rate of sample dissolution was revealed. For HA-gelatin composites, as the gelatin concentration grows, the dissolution rate becomes greater, and a sample of 6.0 g / L concentration has higher resorbability. The results of the research can be used to study the kinetics of dissolution and the biocompatibility of ceramic materials for medicine, namely for reconstructive surgery, dentistry, and development of drug delivery systems.

  20. Controlled release of NELL-1 protein from chitosan/hydroxyapatite-modified TCP particles.

    PubMed

    Zhang, Yulong; Dong, Rui; Park, Yujin; Bohner, Marc; Zhang, Xinli; Ting, Kang; Soo, Chia; Wu, Benjamin M

    2016-09-10

    NEL-like molecule-1 (NELL-1) is a novel osteogenic protein that showing high specificity to osteochondral cells. It was widely used in bone regeneration research by loading onto carriers such as tricalcium phosphate (TCP) particles. However, there has been little research on protein controlled release from this material and its potential application. In this study, TCP was first modified with a hydroxyapatite coating followed by a chitosan coating to prepare chitosan/hydroxyapatite-coated TCP particles (Chi/HA-TCP). The preparation was characterized by SEM, EDX, FTIR, XRD, FM and Zeta potential measurements. The NELL-1 loaded Chi/HA-TCP particles and the release kinetics were investigated in vitro. It was observed that the Chi/HA-TCP particles prepared with the 0.3% (wt/wt) chitosan solution were able to successfully control the release of NELL-1 and maintain a slow, steady release for up to 28 days. Furthermore, more than 78% of the loaded protein's bioactivity was preserved in Chi/HA-TCP particles over the period of the investigation, which was significantly higher than that of the protein released from hydroxyapatite coated TCP (HA-TCP) particles. Collectively, this study suggests that the osteogenic protein NELL-1 showed a sustained release pattern after being encapsulated into the modified Chi/HA-TCP particles, and the NELL-1 integrated composite of Chi/HA-TCP showed a potential to function as a protein delivery carrier and as an improved bone matrix for use in bone regeneration research. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Dissolution-resistance of glass-added hydroxyapatite composites

    NASA Astrophysics Data System (ADS)

    Seo, Dong Seok; Lee, Jong Kook

    2009-04-01

    Hydroxyapatite (HA) has generated a great deal of interest as a promising implant material. However, its poor mechanical properties induced by severe dissolution in biological milieu limit medical applications and lead to clinical failure. In this study, HA ceramics with 30P2O5-30CaO-40Na2O glass (1.0 wt.% and 2.5 wt.%) were prepared to improve the resistance of monophase HA. The monophase HA sintered body showed microstructural degradation due to grain boundary dissolution in buffered water. However, the dissolution-resistance of HA/glass composites was significantly improved and showed no apparent evidence of dissolution. This suggests that a less soluble glass phase should be placed at grain boundaries to protect HA from dissolution.

  2. Development of implants composed of bioactive materials for bone repair

    NASA Astrophysics Data System (ADS)

    Xiao, Wei

    The purpose of this Ph.D. research was to address the clinical need for synthetic bioactive materials to heal defects in non-loaded and loaded bone. Hollow hydroxyapatite (HA) microspheres created in a previous study were evaluated as a carrier for controlled release of bone morphogenetic protein-2 (BMP2) in bone regeneration. New bone formation in rat calvarial defects implanted with BMP2-loaded microspheres (43%) was significantly higher than microspheres without BMP2 (17%) at 6 weeks postimplantation. Then hollow HA microspheres with a carbonate-substituted composition were prepared to improve their resorption rate. Hollow HA microspheres with 12 wt. % of carbonate showed significantly higher new bone formation (73 +/- 8%) and lower residual HA (7 +/- 2%) than stoichiometric HA microspheres (59 +/- 2% new bone formation; 21 +/- 3% residual HA). The combination of carbonate-substituted hollow HA microspheres and clinically-safe doses of BMP2 could provide promising implants for healing non-loaded bone defects. Strong porous scaffolds of bioactive silicate (13-93) glass were designed with the aid of finite-element modeling, created by robocasting and evaluated for loaded bone repair. Scaffolds with a porosity gradient to mimic human cortical bone showed a compressive strength of 88 +/- 20 MPa, a flexural strength of 34 +/- 5 MPa and the ability to support bone infiltration in vivo. The addition of a biodegradable polylactic acid (PLA) layer to the external surface of these scaffolds increased their load-bearing capacity in four-point bending by 50% and dramatically enhanced their work of fracture, resulting in a "ductile" mechanical response. These bioactive glass-PLA composites, combining bioactivity, high strength, high work of fracture and an internal architecture conducive to bone infiltration, could provide optimal implants for structural bone repair.

  3. Heat treatment's effects on hydroxyapatite powders in water vapor and air atmosphere

    NASA Astrophysics Data System (ADS)

    Karabulut, A.; Baştan, F. E.; Erdoǧan, G.; Üstel, F.

    2015-03-01

    Hydroxyapatite (HA; Ca10(PO4)6(OH)2) is the main chemical constituent of bone tissue (~70%) as well as HA which is a calcium phosphate based ceramic material forms inorganic tissue of bone and tooth as hard tissues is used in production of prosthesis for synthetic bone, fractured and broken bone restoration, coating of metallic biomaterials and dental applications because of its bio compatibility. It is known that Hydroxyapatite decomposes with high heat energy after heat treatment. Therefore hydroxyapatite powders that heated in water vapor will less decomposed phases and lower amorphous phase content than in air atmosphere. In this study high purity hydroxyapatite powders were heat treated with open atmosphere furnace and water vapor atmosphere with 900, 1000, 1200 °C. Morphology of same powder size used in this process by SEM analyzed. Chemical structures of synthesized coatings have been examined by XRD. The determination of particle size and morphological structure of has been characterized by Particle Sizer, and SEM analysis, respectively. Weight change of sample was recorded by thermogravimetric analysis (TGA) during heating and cooling.

  4. Hydroxyapatite-alginate nanocomposite as drug delivery matrix for sustained release of ciprofloxacin.

    PubMed

    Venkatasubbu, G Devanand; Ramasamy, S; Ramakrishnan, V; Kumar, J

    2011-12-01

    Hydroxyapatite is a bioceramic which has a wide range of medical application for bone diseases. To enhance its usage, we have prepared ciprofloxacin loaded nano hydroxyapatite (HA) composite with a natural polymer, alginate, using wet chemical method at low temperature. The prepared composites were analyzed by various physicochemical methods. The results show that the nano HA crystallites are well intact with the alginate macromolecules. For the composite system FT-IR and micro Raman results are reported in this paper. Studies on the drug loading and drug release have been done. The drug is pre-adsorbed onto the ceramic particle before the formation of composite. The thermal behavior of composite has been studied using thermo gravimetric analysis (TGA). This work, reports that the nanocomposite prepared under optimum condition could prolong the release of ciprofloxacin compared with the ciprofloxacin loaded hydroxyapatite.

  5. In vitro testing of calcium phosphate (HA, TCP, and biphasic HA-TCP) whiskers.

    PubMed

    Jalota, Sahil; Bhaduri, Sarit B; Tas, A Cuneyt

    2006-09-01

    Calcium phosphate [single-phase hydroxyapatite (HA, Ca(10)(PO(4))(6)(OH)(2)), single-phase tricalcium phosphate (beta-TCP, Ca(3)(PO(4))(2)), and biphasic HA-TCP] whiskers were formed by using a novel microwave-assisted molten salt mediated process. Aqueous solutions containing NaNO(3), HNO(3), Ca(NO(3))(2) x 4H(2)O, and KH(2)PO(4) (with or without urea) were used as starting reagents. These solutions were irradiated in a household microwave oven for 5 min. As-recovered precursors were then simply stirred in water at room temperature for 1 h to obtain the whiskers of the desired calcium phosphate (CaP) bioceramics. These whiskers were evaluated, respectively, in vitro by (1) soaking those in synthetic body fluid (SBF) solutions at 37 degrees C for one week, and (2) performing cell attachment and total protein assay tests on the neat whiskers by using a mouse osteoblast cell line (7F2). beta-TCP, HA, and HA-TCP biphasic whiskers were all found to possess apatite-inducing ability when soaked in SBF. SBF-soaked whiskers were found to have BET surface areas ranging from 45 to 112 m(2)/g. Although the osteoblast viability and protein concentrations were found to be the highest on the neat HA whiskers, cells were attached and proliferated on all the whiskers.

  6. Biomedical properties of laser prepared silver-doped hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Jelínek, M.; Weiserová, M.; Kocourek, T.; Zezulová, M.; Strnad, J.

    2011-07-01

    Thin films of hydroxyapatite (HA) and silver-doped HA were synthesized using KrF excimer laser deposition. Material was ablated from one target composed from silver and HA segments. Layers properties as silver content, structure, color, FTIR spectra and antibacterial properties (Gram-positive Bacillus subtilis) were measured. Silver concentration in HA layers of 0.06, 0.3, 1.2, 4.4, 8.3, and 13.7 at % was detected. The antibacterial efficacy changed with silver dopation from 71.0 to 99.9%. The focus is on investigation of minimum Ag concentration needed to reach a high antibacterial efficacy.

  7. On the fate of particles liberated from hydroxyapatite coatings in vivo.

    PubMed

    Dunne, C F; Gibbons, J; FitzPatrick, D P; Mulhall, K J; Stanton, K T

    2015-03-01

    Hydroxyapatite (HA) has been used as a coating for orthopaedic implants for over 30 years to help promote the fixation of orthopaedic implants into the surrounding bone. However, concerns exist about the fate of the hydroxyapatite coating and hydroxyapatite particles in vivo, especially in the wake of recent concerns about particulates from metal-on-metal bearings. Here, we assess the mechanisms of particle detachment from coated orthopaedic devices as well as the safety and performance concerns and biomedical implications arising from the liberation of the particles by review of the literature. The mechanisms that can result in the detachment of the HA coating from the implant can be mechanical or biochemical, or both. Mechanical mechanisms include implant insertion, abrasion, fatigue and micro-motion. Biochemical mechanisms that contribute to the liberation of HA particles include dissolution into extra-cellular fluid, cell-mediated processes and crystallisation of amorphous phases. The form the particles take once liberated is influenced by a number of factors such as coating method, the raw powder morphology, processing parameters, coating thickness and coating structure. This review summarises and discusses each of these factors and concludes that HA is a safe biomimetic material to use as a coating and does not cause any problems in particulate form if liberated as debris from an orthopaedic implant.

  8. Bone-like apatite layer formation on hydroxyapatite prepared by spark plasma sintering (SPS).

    PubMed

    Gu, Y W; Khor, K A; Cheang, P

    2004-08-01

    Hydroxyapatite (HA) compacts with high density and superior mechanical properties were fabricated by spark plasma sintering (SPS) using spray-dried HA powders as feedstock. The formation of bone-like apatite layer on SPS consolidated HA compacts were investigated by soaking the HA compacts in simulated body fluid (SBF) for various periods (maximum of 28 days). The structural changes in HA post-SBF were analyzed with scanning electron microscopy, grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy. It was found that a layer consisting microcrystalline carbonate-containing hydroxyapatite was formed on the surface of HA compacts after soaking for 24h. The formation mechanism of apatite on the surface of HA compacts after soaking in SBF was attributed to the ion exchange between HA compacts and the SBF solution. The increase in ionic concentration of calcium and phosphorus as well as the increase in pH after SBF immersion resulted in an increase in ionic activity product of apatite in the solution, and provided a specific surface with a low interface energy that is conducive to the nucleation of apatite on the surface of HA compacts.

  9. Characterisation of Suspension Precipitated Nanocrystalline Hydroxyapatite Powders

    NASA Astrophysics Data System (ADS)

    Mallik, P. K.; Swain, P. K.; Patnaik, S. C.

    2016-02-01

    Hydroxyapatite (HA) is a well-known biomaterial for coating on femoral implants, filling of dental cavity and scaffold for tissue replacement. Hydroxyapatite possess limited load bearing capacity due to their brittleness. In this paper, the synthesis of nanocrystalline hydroxyapatite powders was prepared by dissolving calcium oxide in phosphoric acid, followed by addition of ammonia liquor in a beaker. The prepared solution was stirred by using magnetic stirrer operated at temperature of 80°C for an hour. This leads to the formation of hydroxyapatite precipitate. The precipitate was dried in oven for overnight at 100°C. The dried agglomerated precipitate was calcined at 800°C in conventional furnace for an hour. The influence of calcium oxide concentration and pH on the resulting precipitates was studied using BET, XRD and SEM. As result, a well-defined sub-rounded morphology of powders size of ∼41 nm was obtained with a salt concentration of 0.02 M. Finally, it can be concluded that small changes in the reaction conditions led to large changes in final size, shape and degree of aggregation of the hydroxyapatite particles.

  10. Removal of Uranium in Drinking Water: Brimac Environmental Services, Inc. Brimac HA 216 Adsorptive Media

    EPA Science Inventory

    The Brimac HA 216 Adsorptive Media was tested for uranium (U) removal from a drinking water source (well water) at Grappone Toyota located in Bow, New Hampshire. The HA 216 media is a hydroxyapatite-based material. A pilot unit, consisting of a TIGG Corporation Cansorb® C-5 ste...

  11. Electrophoretic Deposition of Hydroxyapatite Film Containing Re-Doped MoS₂ Nanoparticles.

    PubMed

    Shalom, Hila; Feldman, Yishay; Rosentsveig, Rita; Pinkas, Iddo; Kaplan-Ashiri, Ifat; Moshkovich, Alexey; Perfilyev, Vladislav; Rapoport, Lev; Tenne, Reshef

    2018-02-26

    Films combining hydroxyapatite (HA) with minute amounts (ca. 1 weight %) of (rhenium doped) fullerene-like MoS₂ (IF) nanoparticles were deposited onto porous titanium substrate through electrophoretic process (EPD). The films were analyzed by scanning electron microscopy (SEM), X-ray diffraction and Raman spectroscopy. The SEM analysis showed relatively uniform coatings of the HA + IF on the titanium substrate. Chemical composition analysis using energy dispersive X-ray spectroscopy (EDS) of the coatings revealed the presence of calcium phosphate minerals like hydroxyapatite, as a majority phase. Tribological tests were undertaken showing that the IF nanoparticles endow the HA film very low friction and wear characteristics. Such films could be of interest for various medical technologies. Means for improving the adhesion of the film to the underlying substrate and its fracture toughness, without compromising its biocompatibility are discussed at the end.

  12. Antimicrobial and osteogenic properties of a hydrophilic-modified nanoscale hydroxyapatite coating on titanium.

    PubMed

    Murakami, Asuka; Arimoto, Takafumi; Suzuki, Dai; Iwai-Yoshida, Misato; Otsuka, Fukunaga; Shibata, Yo; Igarashi, Takeshi; Kamijo, Ryutaro; Miyazaki, Takashi

    2012-04-01

    Hydroxyapatite (HA)-coated titanium (Ti) is commonly used for implantable medical devices. This study examined in vitro osteoblast gene expression and antimicrobial activity against early and late colonizers of supra-gingival plaque on nanoscale HA-coated Ti prepared by discharge in a physiological buffered solution. The HA-coated Ti surface showed super-hydrophilicity, whereas the densely sintered HA and Ti surfaces alone showed lower hydrophilicity. The sintered HA and HA-coated Ti surfaces enhanced osteoblast phenotypes in comparison with the bare Ti surface. The HA-coated Ti enabled antimicrobial activity against early colonizers of supra-gingival plaques, namely Streptococcus mitis and Streptococcus gordonii. Such antimicrobial activity may be caused by the surface hydrophilicity, thereby leading to a repulsion force between the HA-coated Ti surface and the bacterial cell membranes. On the contrary, the sintered HA sample was susceptible to infection of microorganisms. Thus, hydrophilic-modified HA-coated Ti may have potential for use in implantable medical devices. From the Clinical Editor: This study establishes that Hydroxyapatite (HA)-coated titanium (Ti) surface of implanted devices may result in an optimal microenvironment to control and prevent infections and may have potential future clinical applications. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Growth of hydroxyapatite in a biocompatible mesoporous ordered silica.

    PubMed

    Díaz, A; López, T; Manjarrez, J; Basaldella, E; Martínez-Blanes, J M; Odriozola, J A

    2006-03-01

    A novel biomaterial (HA-SBA-15) has been developed based on the growth of calcium phosphate hydroxyapatite (HA) nanoparticles within an organized silica structure (SBA-15). Characterization of the material was carried out using a combination of X-ray diffraction, X-ray fluorescence, transmission electron microscopy, N2 adsorption-desorption isotherms and nuclear magnetic resonance. Transmission electron microscopy observations and N2 porosimetry revealed the crystallization of hydroxyapatite nanoparticles inside the mesopore cavities of the silica structure. Specific surface areas of 760 m2 g(-1) and 260 m2 g(-1) were measured for the SBA-15 and the HA-SBA-15 material, respectively. The hydroxyl groups present in the silica nanostructure surface have brought about cationic defects in the silicium sites, mainly with those of tetrahedral symmetry, and promoted the formation of siloxanes. 29Si MAS-NMR analysis shows a significant reduction of the silanol groups concentration with HA growing within the base (SBA-15) material. Studies and brain tissue biocompatibility tests were carried out. Histopathological studies on the SBA-15 implant material showed no changes to the tissue nearby. The results confirmed the synthesis of a silica-based composite containing HA nanoparticles with the potential for biomedical applications.

  14. [Remediation Pb, Cd contaminated soil in lead-zinc mining areas by hydroxyapatite and potassium chloride composites].

    PubMed

    Wang, Li; Li, Yong-Hua; Ji, Yan-Fang; Yang, Lin-Sheng; Li, Hai-Rong; Zhang, Xiu-Wu; Yu, Jiang-Ping

    2011-07-01

    The composite agents containing potassium chloride (KCl) and Hydroxyapatite (HA) were used to remediate the lead and cadmium contaminated soil in Fenghuang lead-zinc mining-smelting areas, Hunan province. The objective of this study was to identify and evaluate the influence of Cl- to the fixing efficiency of Pb and Cd by HA. Two types of contaminated soil (HF-1, HF-2) were chosen and forty treatments were set by five different Hydroxyapatite (HA) dosages and four different Cl- dosages. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the results. It showed that HA could efficiently fix the Pb and Cd from TCLP form. The maximum Pb-fixing efficiency and Cd-fixing efficiency of two types of soil were 83.3%, 97.27% and 35.96%, 57.82% when the HA: Pb: KCl molar ratio was 8: 1: 2. Compared to the fixing efficiency without KCl, KCl at the KCl: Pb molar ratio of 2 improved Pb-fixing efficiency and Cd-fixing efficiency by 6.26%, 0.33% and 7.74%, 0.83% respectively when the HA: Pb molar ratio was 8. Generally, Cl- can improve the Pb/Cd-fixing efficiency in heavy metal contaminated soil by Hydroxyapatite.

  15. Collagen hydrolysate based collagen/hydroxyapatite composite materials

    NASA Astrophysics Data System (ADS)

    Ficai, Anton; Albu, Madalina Georgiana; Birsan, Mihaela; Sonmez, Maria; Ficai, Denisa; Trandafir, Viorica; Andronescu, Ecaterina

    2013-04-01

    The aim of this study was to study the influence of collagen hydrolysate (HAS) on the formation of ternary collagen-hydrolysate/hydroxyapatite composite materials (COLL-HAS/HA). During the precipitation process of HA, a large amount of brushite is resulted at pH = 7 but, practically pure HA is obtained at pH ⩾ 8. The FTIR data reveal the duplication of the most important collagen absorption bands due to the presence of the collagen hydrolysate. The presence of collagen hydrolysate is beneficial for the management of bone and joint disorders such as osteoarthritis and osteoporosis.

  16. [The preparation of a new hydroxyapatite and the study on its cytocompatibility].

    PubMed

    Tao, Kai; Mao, Tianqiu; Chen, Fulin; Liu, Xiaoyan

    2006-08-01

    The cuttlebones, harvested from cuttles, undergo the chemical reaction in high temperature and high pressure for a certain time. The products are qualitatively analysed, and spacial structure observation and cytocompatibility are tested. The results show that the chemical component of the cuttlebone is CaCO3 and the crystal type is aragonite. Cuttlebones undergo a hydro-thermal reaction, and thus transform into hydroxyapatite-that is, the cuttlebone-transformed hydroxyapatite(CBHA). The CBHA materials have the interconnected microporous network structures. Under the high magnification, CBHAs appear to have many micro-spheres, thus construct a new self-assembled nano-material system. The marrow stromal osteoblasts can adhere to and proliferate well on the surface of the CBHAs. These results show that CBHAs have good biocompatibility. Therefore, it can be a potential candidate scaffold for bone tissue engineering.

  17. HDPE-HA composites synthetized by in situ polymerization with different filler content

    NASA Astrophysics Data System (ADS)

    Hermán, V.; Karam, A.; Albano, C.; Romero, K.; González, G.

    2012-07-01

    In Situ ethylene polymerization was used to synthesize high density polyethylene - hydroxyapatite (HDPE-HA) composites, employing Cp2ZrCl2/MAO as catalytic system. A good dispersion of HA into the HDPE matrix was obtained when the following synthesis conditions were combined: high stirring velocities (2000 rpm), low quantities of solvent (100 mL), and 10 °C. Under these conditions different filler content was used to synthetized HDPE-HA composites. An interaction between HA and HDPE was obtained by FTIR. On the other hand, thermal analysis indicated that no significant differences were observed between HDPE and the composites.

  18. Synthesis, characterization and cell behavior of fluoridated hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Qu, Haibo

    Fluorine-containing hydroxyapatite (Ca5(PO4) 3(OH)1-xFx FHA), where F- partially replaces OH- in hydroxyapatite (HA), is recognized as a possible biomaterial for bone and tooth implants and gaining attention in the last several years as a possible alternative to HA. In this study, FHA powders were synthesized through a pH-cycling method. It was discovered that fluorine incorporation increased with the fluorine content in the initial solution and the number of pH cycles employed. A relatively low fluorine incorporation efficiency, ˜60%, was attained for most of the FHA samples. The short time of stay at each pH cycle and the limited number of cycles used are believed to be the main reasons of the low fluorine incorporation into the apatite structure. It was also revealed that the FHA particles produced by the pH-cycling method were inhomogeneous. They were a mixture of hydroxyapatite and F-rich apatite (or FA) particles. The mechanisms of incorporation of fluorine ions into hydroxyapatite by a pH cyclicing method were studied using TEM, XRD and fluorine measurement. Instead of forming laminated structures as reported by other research groups, a mixture of nano-sized F-rich apatite (FHA) and hydroxyapatite (HA) particles were obtained using the pH-cyclicing method. After calcination, these FHA particles were homogenized and became single phased FHA. The effect of fluorine content, preparing method, and sintering temperature on both the bulk density and biaxial flexural strength of sintered FHA was studied. Both uniaxially pressed un-milled (UPU) and cold isostatically pressed milled (IPM) FHA discs were sintered at temperatures between 1200˜400°C at an interval of 100°C. It was found that the fluorine content had a significant impact on the sintering behavior, densification, and mechanical properties of FHA discs. A close correlation between the sintered density and biaxial flexural strength of the specimens was revealed, where the biaxial flexural strength

  19. Efficacy of a mouthrinse based on hydroxyapatite to reduce initial bacterial colonisation in situ.

    PubMed

    Kensche, A; Holder, C; Basche, S; Tahan, N; Hannig, C; Hannig, M

    2017-08-01

    The present in situ - investigation aimed to specify the impact of pure hydroxyapatite microclusters on initial bioadhesion and bacterial colonization at the tooth surface. Pellicle formation was carried out in situ on bovine enamel slabs (9 subjects). After 1min of pellicle formation rinses with 8ml of hydroxyapatite (HA) microclusters (5%) in bidestilled water or chlorhexidine 0.2% were performed. As negative control no rinse was adopted. In situ biofilm formation was promoted by the intraoral slab exposure for 8h overnight. Afterwards initial bacterial adhesion was quantified by DAPI staining and bacterial viability was determined in vivo/in vitro by live/dead-staining (BacLight). SEM analysis evaluated the efficacy of the mouthrinse to accumulate hydroxyapatite microclusters at the specimens' surface and spit-out samples of the testsolution were investigated by TEM. Compared to the control (2.36×10 6 ±2.01×10 6 bacteria/cm 2 ), significantly reduced amounts of adherent bacteria were detected on specimens rinsed with chlorhexidine 0.2% (8.73×10 4 ±1.37×10 5 bacteria/cm 2 ) and likewise after rinses with the hydroxyapatite testsolution (2.08×10 5 ±2.85×10 5 bacteria/cm 2 , p<0.001). No demonstrable effect of HA-particles on Streptococcus mutans viability could be shown. SEM analysis confirmed the temporary adsorption of hydroxyapatite microclusters at the tooth surface. Adhesive interactions of HA-particles with oral bacteria were shown by TEM. Hydroxyapatite microclusters reduced initial bacterial adhesion to enamel in situ considerably and could therefore sensibly supplement current approaches in dental prophylaxis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Injectable alginate/hydroxyapatite gel scaffold combined with gelatin microspheres for drug delivery and bone tissue engineering.

    PubMed

    Yan, Jingxuan; Miao, Yuting; Tan, Huaping; Zhou, Tianle; Ling, Zhonghua; Chen, Yong; Xing, Xiaodong; Hu, Xiaohong

    2016-06-01

    Injectable and biodegradable alginate-based composite gel scaffolds doubly integrated with hydroxyapatite (HAp) and gelatin microspheres (GMs) were cross-linked via in situ release of calcium cations. As triggers of calcium cations, CaCO3 and glucono-D-lactone (GDL) were fixed as a mass ratio of 1:1 to control pH value ranging from 6.8 to 7.2 during gelation. Synchronously, tetracycline hydrochloride (TH) was encapsulated into GMs to enhance bioactivity of composite gel scaffolds. The effects of HAp and GMs on characteristics of gel scaffolds, including pH value, gelation time, mechanical properties, swelling ratio, degradation behavior and drug release, were investigated. The results showed that HAp and GMs successfully improved mechanical properties of gel scaffolds at strain from 0.1 to 0.5, which stabilized the gel network and decreased weight loss, as well as swelling ratio and gelation time. TH could be released from this composite gel scaffold into the local microenvironment in a controlled fashion by the organic/inorganic hybrid of hydrogel network. Our results demonstrate that the HAp and GMs doubly integrated alginate-based gel scaffolds, especially the one with 6% (w/v) HAp and 5% (w/v) GMs, have suitable physical performance and bioactive properties, thus provide a potential opportunity to be used for bone tissue engineering. The potential application of this gel scaffold in bone tissue engineering was confirmed by encapsulation behavior of osteoblasts. In combination with TH, the gel scaffold exhibited beneficial effects on osteoblast activity, which suggested a promising future for local treatment of pathologies involving bone loss. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Effect of Water-Glass Coating on HA and HA-TCP Samples for MSCs Adhesion, Proliferation, and Differentiation.

    PubMed

    Bajpai, Indu; Kim, Duk Yeon; Kyong-Jin, Jung; Song, In-Hwan; Kim, Sukyoung

    2016-01-01

    Ca-P and silicon based materials have become very popular as bone tissue engineering materials. In this study, water-glass (also known as sodium silicate glass) was coated on sintered hydroxyapatite (HA) and HA-TCP (TCP stands for tricalcium phosphate) samples and subsequently heat-treated at 600°C for 2 hrs. X-rays diffraction showed the presence of β- and α-TCP phases along with HA in the HA-TCP samples. Samples without coating, with water-glass coating, and heat-treated after water-glass coating were used to observe the adhesion and proliferation response of bone marrow derived-mesenchymal stem cells (MSCs). Cell culture was carried out for 4 hrs, 1 day, and 7 days. Interestingly, all samples showed similar response for cell adhesion and proliferation up to 7-day culture but fibronectin, E-cadherin, and osteogenic differentiation related genes (osteocalcin and osteopontin) were significantly induced in heat-treated water-glass coated HA-TCP samples. A water-glass coating on Ca-P samples was not found to influence the cell proliferation response significantly but activated some extracellular matrix genes and induced osteogenic differentiation in the MSCs.

  2. Hydroxyapatite-magnetite-MWCNT nanocomposite as a biocompatible multifunctional drug delivery system for bone tissue engineering.

    PubMed

    Pistone, Alessandro; Iannazzo, Daniela; Panseri, Silvia; Montesi, Monica; Tampieri, Anna; Galvagno, Signorino

    2014-10-24

    New magnetic hydroxyapatite-based nanomaterials as bone-specific systems for controlled drug delivery have been synthesized. The synthesized hydroxyapatite, HA, decorated with magnetite nanoparticles by a deposition method (HA/Fe3O4) and the nanocomposite system obtained using magnetic multi-walled carbon nanotubes (HA/MWCNT/Fe3O4) as a filler for HA have been characterized by chemical and morphological analyses, and their biological behavior was investigated. The systems have also been doped with clodronate in order to combine the effect of bone biomineralization induced by hydroxyapatite-based composites with the decrease of osteoclast formation induced by the drug. An analysis of the preosteoclastic RAW264.7 cell proliferation by MTT assay confirmed the high biocompatibility of the three systems. TRAP staining of RAW 264.7 conditioned with sRAKL to induce osteoclastogenesis, cultured in the presence of the systems doped and undoped with clodronate, showed the inhibitory effect of clodronate after we counted the MNC TRAP(+)cells but only in the osteoclast formation; in particular, the system HA/Fe3O4-Clo exerted a high inhibitory effect compared to the drug alone. These results demonstrate that the synthesized nanocomposites are a biocompatible magnetic drug delivery system and can represent a useful multimodal platform for applications in bone tissue engineering.

  3. Nanocrystallinity effects on osteoblast and osteoclast response to silicon substituted hydroxyapatite.

    PubMed

    Casarrubios, Laura; Matesanz, María Concepción; Sánchez-Salcedo, Sandra; Arcos, Daniel; Vallet-Regí, María; Portolés, María Teresa

    2016-11-15

    Silicon substituted hydroxyapatites (SiHA) are highly crystalline bioceramics treated at high temperatures (about 1200°C) which have been approved for clinical use with spinal, orthopedic, periodontal, oral and craniomaxillofacial applications. The preparation of SiHA with lower temperature methods (about 700°C) provides nanocrystalline SiHA (nano-SiHA) with enhanced bioreactivity due to higher surface area and smaller crystal size. The aim of this study has been to know the nanocrystallinity effects on the response of both osteoblasts and osteoclasts (the two main cell types involved in bone remodelling) to silicon substituted hydroxyapatite. Saos-2 osteoblasts and osteoclast-like cells (differentiated from RAW-264.7 macrophages) have been cultured on the surface of nano-SiHA and SiHA disks and different cell parameters have been evaluated: cell adhesion, proliferation, viability, intracellular content of reactive oxygen species, cell cycle phases, apoptosis, cell morphology, osteoclast-like cell differentiation and resorptive activity. This comparative in vitro study evidences that nanocrystallinity of SiHA affects the cell/biomaterial interface inducing bone cell apoptosis by loss of cell anchorage (anoikis), delaying osteoclast-like cell differentiation and decreasing the resorptive activity of this cell type. These results suggest the potential use of nano-SiHA biomaterial for preventing bone resorption in treatment of osteoporotic bone. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Monolithic Pellets, Composites and Thick Films of Hydroxyapatite: Correlation of Mechanical Properties with Microstructure.

    NASA Astrophysics Data System (ADS)

    Wang, Pauchiu Either

    Hydroxyapatite Ca_{10}(PO _4)_6(OH)_2 (abbreviated as HA) has great biocompatibility. Poor mechanical properties of HA implants and decomposition of HA during processing are the major obstacles for widespread uses of HA. In the present thesis we have attempted to understand the sintering behavior of monolithic HA and metal-reinforced HA-matrix composites, and the mechanism of formation of HA coating in the solutions at the normal temperature. The powders of two calcium phosphates, namely hydroxyapatite and dicalcium phosphate (DCP: chemical formula Ca_2P_2O_7), were sintered at various temperatures and in various environments. The density, flexural strength and knoop hardness of both phosphates sintered in air for 4 h initially increased with the sintering temperature, reaching maxima at around 1000-1150 ^circC, and then decreased due to decomposition. To reduce dehydroxylation, HA powder was sintered in moisture at various temperatures up to 1350^circ C and X-ray diffraction study did not indicate any decomposition at the highest sintering temperature. It is seen that dehydroxylation did not hinder sintering, but decomposition obstructed sintering of both HA and DCP. Ductile-phase reinforcement of hydroxyapatite was achieved by addition of silver particulates (5-30 vol.%) in HA powder compacts. A composite made by sintering 10 vol.% Ag and balance HA at 1200^circ C for 1 h in air had flexural strength of 75 +/- 7 MPa, which was almost double that of pure HA sintered under an identical condition. Silver in the composite melted during sintering, but due to poor wetting, did not spread in between HA particles. The increase in the flexural strength of the composites was thought to be due to crack-bridging and crack-arrest by silver inclusions. Thick films (several μm) of hydroxyapatite were deposited on silicon single crystal placed in close proximity to a plate of apatite- and wollastonite -containing glass and dipped into a simulated body fluid (SBF) at 36^circ

  5. Improvement of the stability of hydroxyapatite through glass ceramic reinforcement.

    PubMed

    Ha, Na Ra; Yang, Zheng Xun; Hwang, Kyu Hong; Kim, Tae Suk; Lee, Jong Kook

    2010-05-01

    Hydroxyapatite has achieved significant application in orthopedic and dental implants due to its excellent biocompatibility. Sintered hydroxyapatites showed significant dissolution, however, after their immersion in water or simulated body fluid (SBF). This grain boundary dissolution, even in pure hydroxyapatites, resulted in grain separation at the surfaces, and finally, in fracture. In this study, hydroxyapatite ceramics containing apatite-wollastonite (AW) or calcium silicate (SG) glass ceramics as additives were prepared to prevent the dissolution. AW and SG glass ceramics were added at 0-7 wt% and powder-compacted uniaxially followed by firing at moisture conditions. The glass phase was incorporated into the hydroxyapatite to act as a sintering aid, followed by crystallization, to improve the mechanical properties without reducing the biocompatibility. As seen in the results of the dissolution test, a significant amount of damage was reduced even after more than 14 days. TEM and SEM showed no decomposition of HA to the secondary phase, and the fracture toughness increased, becoming even higher than that of the commercial hydroxyapatite.

  6. Support for the initial attachment, growth and differentiation of MG-63 cells: a comparison between nano-size hydroxyapatite and micro-size hydroxyapatite in composites

    PubMed Central

    Filová, Elena; Suchý, Tomáš; Sucharda, Zbyněk; Šupová, Monika; Žaloudková, Margit; Balík, Karel; Lisá, Věra; Šlouf, Miroslav; Bačáková, Lucie

    2014-01-01

    Hydroxyapatite (HA) is considered to be a bioactive material that favorably influences the adhesion, growth, and osteogenic differentiation of osteoblasts. To optimize the cell response on the hydroxyapatite composite, it is desirable to assess the optimum concentration and also the optimum particle size. The aim of our study was to prepare composite materials made of polydimethylsiloxane, polyamide, and nano-sized (N) or micro-sized (M) HA, with an HA content of 0%, 2%, 5%, 10%, 15%, 20%, 25% (v/v) (referred to as N0–N25 or M0–M25), and to evaluate them in vitro in cultures with human osteoblast-like MG-63 cells. For clinical applications, fast osseointegration of the implant into the bone is essential. We observed the greatest initial cell adhesion on composites M10 and N5. Nano-sized HA supported cell growth, especially during the first 3 days of culture. On composites with micro-size HA (2%–15%), MG-63 cells reached the highest densities on day 7. Samples M20 and M25, however, were toxic for MG-63 cells, although these composites supported the production of osteocalcin in these cells. On N2, a higher concentration of osteopontin was found in MG-63 cells. For biomedical applications, the concentration range of 5%–15% (v/v) nano-size or micro-size HA seems to be optimum. PMID:25125978

  7. Thermal Diffusivity in Bone and Hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Calderón, A.; Peña Rodríguez, G.; Muñoz Hernández, R. A.; Díaz Gongora, J. A. I.; Mejia Barradas, C. M.

    2004-09-01

    We report thermal diffusivity measurements in bull bone and commercial hydroxyapatite (HA), both in powder form, in order to determinate the thermal compatibility between these materials. Besides this, we report a comparison between these measured values and those of metallic samples frequently used in implants, as high purity titanium and stainless steel. Our results show a good thermal compatibility (74%) between HA and bone, both in powder form. Finally, it was obtained a one order of magnitude difference between the thermal diffusivity values of metallic samples and those corresponding values to bone and HA being this difference greater in titanium than in stainless steel, which is important to consider in some biomedical and dental applications.

  8. Limitation of biocompatibility of hydrated nanocrystalline hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Minaychev, V. V.; Teleshev, A. T.; Gorshenev, V. N.; Yakovleva, M. A.; Fomichev, V. A.; Pankratov, A. S.; Menshikh, K. A.; Fadeev, R. S.; Fadeeva, I. S.; Senotov, A. S.; Kobyakova, M. I.; Yurasova, Yu B.; Akatov, V. S.

    2018-04-01

    Nanostructured hydroxyapatite (HA) in the form of hydrated paste is considered to be a promising material for a minor-invasive surgical curing of bone tissue injure. However questions about adhesion of cells on this material and its biocompatibility still remain. In this study biocompatibility of paste-formed nanosized HA (nano-HA) by in vitro methods is investigated. Nano-HA (particles sized about 20 nm) was synthesized under conditions of mechano-acoustic activation of an aqueous reaction mixture of ammonium hydrophosphate and calcium nitrate. It was ascertained that nanocrystalline paste was not cytotoxic although limitation of adhesion, spreading and growth of the cells on its surface was revealed. The results obtained point on the need of modification of hydrated nano-HA in the aims of increasing its biocompatibility and osteoplastic potential.

  9. Impact of water chemistry on surface charge and aggregation of polystyrene microspheres suspensions.

    PubMed

    Lu, Songhua; Zhu, Kairuo; Song, Wencheng; Song, Gang; Chen, Diyun; Hayat, Tasawar; Alharbi, Njud S; Chen, Changlun; Sun, Yubing

    2018-07-15

    The discharge of microplastics into aquatic environment poses the potential threat to the hydrocoles and human health. The fate and transport of microplastics in aqueous solutions are significantly influenced by water chemistry. In this study, the effect of water chemistry (i.e., pH, foreign salts and humic acid) on the surface charge and aggregation of polystyrene microsphere in aqueous solutions was conducted by batch, zeta potentials, hydrodynamic diameters, FT-IR and XPS analysis. Compared to Na + and K + , the lower negative zeta potentials and larger hydrodynamic diameters of polystyrene microspheres after introduction of Mg 2+ were observed within a wide range of pH (2.0-11.0) and ionic strength (IS, 0.01-500mmol/L). No effect of Cl - , HCO 3 - and SO 4 2- on the zeta potentials and hydrodynamic diameters of polystyrene microspheres was observed at low IS concentrations (<5mmol/L), whereas the zeta potentials and hydrodynamic diameters of polystyrene microspheres after addition of SO 4 2- were higher than that of Cl - and HCO 3 - at high IS concentrations (>10mmol/L). The zeta potentials of polystyrene microspheres after HA addition were decreased at pH2.0-11.0, whereas the lower hydrodynamic diameters were observed at pH<4.0. According to FT-IR and XPS analysis, the change in surface properties of polystyrene microspheres after addition of hydrated Mg 2+ and HA was attributed to surface electrostatic and/or steric repulsions. These investigations are crucial for understanding the effect of water chemistry on colloidal stability of microplastics in aquatic environment. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Effect of surface roughness of hydroxyapatite-coated titanium on the bone-implant interface shear strength.

    PubMed

    Hayashi, K; Inadome, T; Tsumura, H; Nakashima, Y; Sugioka, Y

    1994-11-01

    We have investigated the bone-implant interface shear strength of hydroxyapatite (HA)-coated Ti-6Al-4V (HA-coating A) (roughness average, Ra = 3.4 +/- 0.5 microns) and HA-coated Ti-6Al-4V with a rougher surface (HA-coating B) (Ra = 8.4 +/- 1.8 microns). There was no significant difference between HA-coating A and HA-coating B implants with respect to the bone-implant interface shear strength as determined in push-out tests using the transcortical model in adult dogs. The bone-implant interface shear strength of bead-coated porous Ti-6Al-4V was significantly greater than that of both HA-coating A and HA-coating B implants. The failure site, as determined by scanning electron microscopy, was the coating-substrate interface, not the coating-bone interface. This indicates a need to protect the HA coating from the direct shear forces. HA coating enhances early bone growth into the porous surface of the implant. Long-term fixation should depend on bone anchoring to this porous surface. Hydroxyapatite coatings must be developed which do not obstruct the pores of the surface of the implant.

  11. Electrophoretic Deposition of Hydroxyapatite Film Containing Re-Doped MoS2 Nanoparticles

    PubMed Central

    Shalom, Hila; Feldman, Yishay; Rosentsveig, Rita; Pinkas, Iddo; Kaplan-Ashiri, Ifat; Moshkovich, Alexey; Perfilyev, Vladislav; Rapoport, Lev

    2018-01-01

    Films combining hydroxyapatite (HA) with minute amounts (ca. 1 weight %) of (rhenium doped) fullerene-like MoS2 (IF) nanoparticles were deposited onto porous titanium substrate through electrophoretic process (EPD). The films were analyzed by scanning electron microscopy (SEM), X-ray diffraction and Raman spectroscopy. The SEM analysis showed relatively uniform coatings of the HA + IF on the titanium substrate. Chemical composition analysis using energy dispersive X-ray spectroscopy (EDS) of the coatings revealed the presence of calcium phosphate minerals like hydroxyapatite, as a majority phase. Tribological tests were undertaken showing that the IF nanoparticles endow the HA film very low friction and wear characteristics. Such films could be of interest for various medical technologies. Means for improving the adhesion of the film to the underlying substrate and its fracture toughness, without compromising its biocompatibility are discussed at the end. PMID:29495394

  12. Invitro Evaluation of Fluoride Release from Hydroxyapatite Reinforced Glass Ionomer with or without Protective Coating.

    PubMed

    Tiwari, Shilpi; Nandlal, Bhojraj

    2016-04-01

    Glass Ionomer Cement (GIC) is well known for its fluoride releasing property but has its own drawbacks of poor mechanical properties, sensitivity to initial desiccation and moisture contamination. To overcome these, search led to the reinforcement of hydroxyapatite and application of surface coating agent but their effect on fluoride release is still not clear. To evaluate and compare the release of fluoride from Hydroxyapatite Reinforced Glass Ionomer (HA-GIC) with and without protective coating. Specimens were prepared as follows- Eight percent by weight conventional glass ionomer was replaced by hydroxyapatite powder (HA) and an indigenous product was prepared (HA-GIC). This powder was mixed with liquid of conventional GIC and allowed to set, then G coat plus coating agent was applied in surface coated group and light cured. Fluoride release of the sample was measured every 24 hrs for seven days and weekly from 7(th) to 21(st) day using combination ion selective electrode. Mean values clearly reveal a significant decrease in the fluoride release from day 1 to day 21 for both the groups. Results of repeated measure ANOVA revealed statistically significant difference between two groups (p <0.001). Coating the hydroxyapatite reinforced glass ionomer will allow for slow and steady release of fluoride for a long period of time into oral environment.

  13. Osteoconductive composite graft based on bacterial synthesized hydroxyapatite nanoparticles doped with different ions: From synthesis to in vivo studies.

    PubMed

    Ahmadzadeh, Elham; Talebnia, Farid; Tabatabaei, Meisam; Ahmadzadeh, Hossein; Mostaghaci, Babak

    2016-07-01

    To repair damaged bone tissues, osteoconductive bone graft substitutes are required for enhancement of the regenerative potential of osteoblast cells. Nanostructured hydroxyapatite is a bioactive ceramic used for bone tissue engineering purposes. In this study, carbonate hydroxyapatite (cHA) and zinc-magnesium substituted hydroxyapatite (Zn-Mg-HA) nanoparticles were synthesized via biomineralization method using Enterobacter aerogenes. The structural phase composition and the morphology of the samples were analyzed using appropriate powder characterization methods. Next, a composite graft was fabricated by using polyvinyl alcohol and both cHA and Zn-Mg-HA samples. In vivo osteogenic potential of the graft was then investigated in a rabbit tibial osteotomy model. Histological, radiological and morphological studies showed that the graft was mineralized by the newly formed bone tissue without signs of inflammation or infection after 4 weeks of implantation. These histomorphometric results suggest that the fabricated graft can function as a potent osteoconductive bone tissue substitute. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Evaluation of a setting reaction pathway in the novel composite TiHA-CSD bone cement by FT-Raman and FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Paluszkiewicz, Czesława; Czechowska, Joanna; Ślósarczyk, Anna; Paszkiewicz, Zofia

    2013-02-01

    The aim of this study was to determine a setting reaction pathway in a novel, surgically handy implant material, based on calcium sulfate hemihydrate (CSH) and titanium doped hydroxyapatite (TiHA). The previous studies confirmed superior biological properties of TiHA in comparison to the undoped hydroxyapatite (HA) what makes it highly attractive for future medical applications. In this study the three types of titanium modified HA powders: untreated, calcined at 800 °C, sintered at 1250 °C and CSH were used to produce bone cements. The Fourier Transform-InfraRed (FT-IR) spectroscopy and Raman spectroscopy were applied to evaluate processes taking place during the setting of the studied materials. Our results undoubtedly confirmed that the reaction pathways and the phase compositions differed significantly for set cements and were dependent on the initial heat treatment of TiHA powder. Final materials were multiphase composites consisting of calcium sulfate dihydrate, bassanite, tricalcium phosphate, hydroxyapatite and calcium titanate (perovskite). The FT-IR and Scanning Electron Microscopy (SEM) measurements performed after the incubation of the cement samples in the simulated body fluid (SBF), indicate on high bioactive potential of the obtained bone cements.

  15. Spherical porous hydroxyapatite granules containing composites of magnetic and hydroxyapatite nanoparticles for the hyperthermia treatment of bone tumor.

    PubMed

    Kamitakahara, Masanobu; Ohtoshi, Naohiro; Kawashita, Masakazu; Ioku, Koji

    2016-05-01

    Spherical porous granules of hydroxyapatite (HA) containing magnetic nanoparticles would be suitable for the hyperthermia treatment of bone tumor, because porous HA granules act as a scaffold for bone regeneration, and magnetic nanoparticles generate sufficient heat to kill tumor cells under an alternating magnetic field. Although magnetic nanoparticles are promising heat generators, their small size makes them difficult to support in porous HA ceramics. We prepared micrometer-sized composites of magnetic and HA nanoparticles, and then supported them in porous HA granules composed of rod-like particles. The spherical porous HA granules containing the composites of magnetic and HA nanoparticle were successfully prepared using a hydrothermal process without changing the crystalline phase and heat generation properties of the magnetic nanoparticles. The obtained granules generated sufficient heat for killing tumor cells under an alternating magnetic field (300 Oe at 100 kHz). The obtained granules are expected to be useful for the hyperthermia treatment of bone tumors.

  16. Polymeric microspheres

    DOEpatents

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  17. Development of model hydroxyapatite bone scaffolds with multiscale porosity for potential load bearing applications

    NASA Astrophysics Data System (ADS)

    Dellinger, Jennifer Gwynne

    2005-11-01

    Model hydroxyapatite (HA) bone scaffolds consisting of a latticed pattern of rods were fabricated by a solid freeform fabrication (SFF) technique based on the robotic deposition of colloidal pastes. An optimal HA paste formulation for this method was developed. Local porosity, i.e. microporosity (1--30 mum) and sintering porosity (less than 1 mum), were produced by including polymer microsphere porogens in the HA pastes and by controlling the sintering of the scaffolds. Scaffolds with and without local porosity were evaluated with and without in vitro accelerated degradation. Percent weight loss of the scaffolds and calcium and phosphorus concentrations in solution increased with degradation time. After degradation, compressive strength and modulus decreased significantly for scaffolds with local porosity, but did not change significantly for scaffolds without local porosity. The compressive strength and modulus of scaffolds without local porosity were comparable to human cortical bone and were significantly greater than the scaffolds with local porosity. Micropores in HA disks caused surface pits that increased the surface roughness as compared to non-microporous HA disks. Mouse mesenchymal stem cells extended their cell processes into these microporous pits on HA disks in vitro. ALP expression was prolonged, cell attachment strength increased, and ECM production appeared greater on microporous HA disks compared to non-microporous HA disks and tissue culture treated polystyrene controls. Scaffolds with and without microporosity were implanted in goats bones. Microporous scaffolds with rhBMP-2 increased the percent of the scaffold filled with bone tissue compared to microporous scaffolds without rhBMP-2. Lamellar bone inside scaffolds was aligned near the rods junctions whereas lamellar bone was aligned in a more random configuration away from the rod junctions. Microporous scaffolds stained darkly with toluidine blue beneath areas of contact with new bone. This

  18. Characterization of New PEEK/HA Composites with 3D HA Network Fabricated by Extrusion Freeforming.

    PubMed

    Vaezi, Mohammad; Black, Cameron; Gibbs, David M R; Oreffo, Richard O C; Brady, Mark; Moshrefi-Torbati, Mohamed; Yang, Shoufeng

    2016-05-26

    Addition of bioactive materials such as calcium phosphates or Bioglass, and incorporation of porosity into polyetheretherketone (PEEK) has been identified as an effective approach to improve bone-implant interfaces and osseointegration of PEEK-based devices. In this paper, a novel production technique based on the extrusion freeforming method is proposed that yields a bioactive PEEK/hydroxyapatite (PEEK/HA) composite with a unique configuration in which the bioactive phase (i.e., HA) distribution is computer-controlled within a PEEK matrix. The 100% interconnectivity of the HA network in the biocomposite confers an advantage over alternative forms of other microstructural configurations. Moreover, the technique can be employed to produce porous PEEK structures with controlled pore size and distribution, facilitating greater cellular infiltration and biological integration of PEEK composites within patient tissue. The results of unconfined, uniaxial compressive tests on these new PEEK/HA biocomposites with 40% HA under both static and cyclic mode were promising, showing the composites possess yield and compressive strength within the range of human cortical bone suitable for load bearing applications. In addition, preliminary evidence supporting initial biological safety of the new technique developed is demonstrated in this paper. Sufficient cell attachment, sustained viability in contact with the sample over a seven-day period, evidence of cell bridging and matrix deposition all confirmed excellent biocompatibility.

  19. Surface-enrichment with hydroxyapatite nanoparticles in stereolithography-fabricated composite polymer scaffolds promotes bone repair.

    PubMed

    Guillaume, O; Geven, M A; Sprecher, C M; Stadelmann, V A; Grijpma, D W; Tang, T T; Qin, L; Lai, Y; Alini, M; de Bruijn, J D; Yuan, H; Richards, R G; Eglin, D

    2017-05-01

    Fabrication of composite scaffolds using stereolithography (SLA) for bone tissue engineering has shown great promises. However, in order to trigger effective bone formation and implant integration, exogenous growth factors are commonly combined to scaffold materials. In this study, we fabricated biodegradable composite scaffolds using SLA and endowed them with osteopromotive properties in the absence of biologics. First we prepared photo-crosslinkable poly(trimethylene carbonate) (PTMC) resins containing 20 and 40wt% of hydroxyapatite (HA) nanoparticles and fabricated scaffolds with controlled macro-architecture. Then, we conducted experiments to investigate how the incorporation of HA in photo-crosslinked PTMC matrices improved human bone marrow stem cells osteogenic differentiation in vitro and kinetic of bone healing in vivo. We observed that bone regeneration was significantly improved using composite scaffolds containing as low as 20wt% of HA, along with difference in terms of osteogenesis and degree of implant osseointegration. Further investigations revealed that SLA process was responsible for the formation of a rich microscale layer of HA corralling scaffolds. To summarize, this work is of substantial importance as it shows how the fabrication of hierarchical biomaterials via surface-enrichment of functional HA nanoparticles in composite polymer stereolithographic structures could impact in vitro and in vivo osteogenesis. This study reports for the first time the enhance osteopromotion of composite biomaterials, with controlled macro-architecture and microscale distribution of hydroxyapatite particles, manufactured by stereolithography. In this process, the hydroxyapatite particles are not only embedded into an erodible polymer matrix, as reported so far in the literature, but concentrated at the surface of the structures. This leads to robust in vivo bone formation at low concentration of hydroxyapatite. The reported 3D self-corralling composite

  20. Hydroxyapatite, fluor-hydroxyapatite and fluorapatite produced via the sol-gel method. Optimisation, characterisation and rheology.

    PubMed

    Tredwin, Christopher J; Young, Anne M; Georgiou, George; Shin, Song-Hee; Kim, Hae-Won; Knowles, Jonathan C

    2013-02-01

    Currently, most titanium implant coatings are made using hydroxyapatite and a plasma spraying technique. There are however limitations associated with plasma spraying processes including poor adherence, high porosity and cost. An alternative method utilising the sol-gel technique offers many potential advantages but is currently lacking research data for this application. It was the objective of this study to characterise and optimise the production of Hydroxyapatite (HA), fluorhydroxyapatite (FHA) and fluorapatite (FA) using a sol-gel technique and assess the rheological properties of these materials. HA, FHA and FA were synthesised by a sol-gel method. Calcium nitrate and triethylphosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride (NH4F) were incorporated for the preparation of the sol-gel derived FHA and FA. Optimisation of the chemistry and subsequent characterisation of the sol-gel derived materials was carried out using X-ray Diffraction (XRD) and Differential Thermal Analysis (DTA). Rheology of the sol-gels was investigated using a viscometer and contact angle measurement. A protocol was established that allowed synthesis of HA, FHA and FA that were at least 99% phase pure. The more fluoride incorporated into the apatite structure; the lower the crystallisation temperature, the smaller the unit cell size (changes in the a-axis), the higher the viscosity and contact angle of the sol-gel derived apatite. A technique has been developed for the production of HA, FHA and FA by the sol-gel technique. Increasing fluoride substitution in the apatite structure alters the potential coating properties. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  1. Synthesis of Hydroxyapatite through Ultrasound and Calcination Techniques

    NASA Astrophysics Data System (ADS)

    Akindoyo, John O.; Beg, M. D. H.; Ghazali, Suriati; Akindoyo, Edward O.; Jeyaratnam, Nitthiyah

    2017-05-01

    There is a growing demand for hydroxyapatite (HA) especially in medical applications, production of HA which is totally green is however a challenge. In this research, HA was produced from biowaste through ultrasound followed by calcination techniques. Pre-treatment of the biowaste was effectively achieved through the help of ultrasound. After calcination at 950°C, the obtained HA was characterized through Thermogravimetric (TGA) analysis, X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR). Spectrum of the produced HA was compared with standard HA index. The spectrum is in agreement with the standard HA as confirmed through FTIR, XRD and TGA result. Furthermore, morphological study of the HA through Field emission scanning electron microscope (FESEM) shows almost uniform spherical shape for the HA as expected. Based on the results obtained herein, combining ultrasound with calcination can help to produce pure HA with potential medical applications without the use of any organic solvent.

  2. Hydroxyapatite-binding peptides for bone growth and inhibition

    DOEpatents

    Bertozzi, Carolyn R [Berkeley, CA; Song, Jie [Shrewsbury, MA; Lee, Seung-Wuk [Walnut Creek, CA

    2011-09-20

    Hydroxyapatite (HA)-binding peptides are selected using combinatorial phage library display. Pseudo-repetitive consensus amino acid sequences possessing periodic hydroxyl side chains in every two or three amino acid sequences are obtained. These sequences resemble the (Gly-Pro-Hyp).sub.x repeat of human type I collagen, a major component of extracellular matrices of natural bone. A consistent presence of basic amino acid residues is also observed. The peptides are synthesized by the solid-phase synthetic method and then used for template-driven HA-mineralization. Microscopy reveal that the peptides template the growth of polycrystalline HA crystals .about.40 nm in size.

  3. Sol-gel derived fluor-hydroxyapatite biocoatings on zirconia substrate.

    PubMed

    Kim, Hae-Won; Kong, Young-Min; Bae, Chang-Jun; Noh, Yoon-Jung; Kim, Hyoun-Ee

    2004-07-01

    Fluor-hydroxyapatite (FHA) film was coated on a zirconia (ZrO(2)) substrate by a sol-gel method. An appropriate amount of F ions was incorporated into the hydroxyapatite (HA) during the preparation of the sols. The apatite phase began to crystallize after heat treatment at 400 degrees C, and increased in intensity above 500 degrees C. No decomposition was detected by X-ray diffraction analyses up to 800 degrees C, which illustrates the high thermal stability of the FHA films. The films showed a uniform and dense morphology with a thickness of approximately 1 microm after a precisely controlled heat treatment process. These FHA films adhered firmly to the zirconia substrate, representing notable adhesion strengths of approximately 70 MPa after heat treatment above 500 degrees C. The dissolution rate of the FHA coating layer varied according to the heat treatment temperature, which was closely related to the film crystallinity. The dissolution rate of the FHA film was lower than that of the HA film, suggesting the possibility of a functional gradient coating of HA and FHA. The MG63 cells seeded onto the FHA films proliferated in a similar manner to those seeded onto pure HA ceramic and a plastic control.

  4. Adsorption and bioactivity studies of albumin onto hydroxyapatite surface.

    PubMed

    Mavropoulos, Elena; Costa, Andréa M; Costa, Lilian T; Achete, Carlos A; Mello, Alexandre; Granjeiro, José M; Rossi, Alexandre M

    2011-03-01

    Bovine serum albumin (BSA) may have an inhibitory or promoter effect on hydroxyapatite (HA) nucleation when apatite is precipitated in a medium containing the protein. In this study we evaluated the influence of BSA on the precipitation of calcium phosphate phases (CP) from simulated body fluid (SBF) when the protein was previously bounded to HA surface. The kinetics of BSA immobilization onto hydroxyapatite surface was performed in different buffers and protein concentrations in order to adjust experimental conditions in which BSA was tightly linked to HA surface for long periods in SBF solution. It was shown that for BSA concentration higher than 0.1mg/mL the adsorption to HA surface followed Langmuir-Freundlich mechanisms, which confirmed the existence of cooperative protein-protein interactions on HA surface. Fourier Transformed Infrared Attenuated Total Reflectance Microscopy (FTIRM-ATR) evidenced changes in BSA conformational state in favor of less-ordered structure. Analyses from high resolution grazing incident X-ray diffraction using synchrotron radiation (GIXRD), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) showed that a poorly crystalline calcium phosphate was precipitated on the surface of HA discs coated with BSA, after the immersion in SBF for 4 days. The new bioactive layer had morphological characteristics similar to the one formed on the HA surface without protein. It was identified as a carbonated apatite with preferential crystal growth along apatite 002 direction. The GIXRD results also revealed that BSA layer bound to the surface inhibited the HA dissolution leading to a reduction on the formation of new calcium phosphate phase. 2010 Elsevier B.V. All rights reserved.

  5. The effect of adhesive strength of hydroxyapatite coating on the stability of hydroxyapatite-coated prostheses in vivo at the early stage of implantation

    PubMed Central

    Duan, Yonghong; Zhu, Shu; Guo, Fei; Zhu, Jinyu; Li, Mao; Ma, Jie

    2012-01-01

    Introduction With the increase in joint revision surgery after arthroplasty, defects of hydroxyapatite (HA)-coated prostheses have been observed increasingly often. These defects adversely affect the prosthetic stability in vivo. This study has analyzed the potential effect of the adhesive strength of HA coating on the stability of HA-coated prostheses in vivo after its implantation. Material and methods Sixty experimental rabbits were divided into HA- and Ti-coated groups. HA-coated prostheses were implanted into the bilateral epicondyle of rabbits femurs. Ti-coated prostheses were implanted as control. At different time points(4, 9, and 15 weeks) after implantation, bone tissue samples were fetched out respectively for histomorphometric analysis. Push-out testing was used to detect the ultimate shear strength at the bone-prosthesis interface. Scanning electron microscope (SEM) observation and energy-dispersive X-ray spectroscopy (EDX) analysis were used to observe the changes in surface composition of the prostheses after the ultimate shear strength testing. The coating adhesive strength of two kinds of coatings were also examined by scratch testing. Results Hydroxyapatite coating has an obvious advantage in facilitating osteogenesis and its plays a critical role in the stability of prostheses. However, the ultimate shear strength of HA-coated prostheses is much lower than that of Ti-coated implants (p < 0.01). Further study has demonstrated that the stability of HA-coated prostheses in vivo is affected by the relatively low adhesive strength between coating and substrate. Conclusions Obvious advantage in facilitating osteogenesis around HA-coated prostheses is not the only factor that determines the stability of prostheses in vivo. PMID:22661990

  6. Influence of hydroxyapatite on the corrosion resistance of the Ti-13Nb-13Zr alloy.

    PubMed

    Duarte, Laís T; Biaggio, Sonia R; Rocha-Filho, Romeu C; Bocchi, Nerilso

    2009-05-01

    Electrochemical analyses on the biocompatible alloy Ti-13Nb-13Zr wt% in an electrolyte simulating physiological medium (PBS solution) are reported. Hydroxyapatite (HA) films were obtained on the alloy by electrodeposition at constant cathodic current. Samples of the alloy covered with an anodic-oxide film or an anodic-oxide/HA film were analyzed by open circuit potential and electrochemical impedance spectroscopy measurements during 180 days in the PBS electrolyte. Analyses of the open-circuit potential (E (oc)) values indicated that the oxide/HA film presents better protection characteristics than the oxide only. This behavior was corroborated by the higher film resistances obtained from impedance data, indicating that, besides improving the alloy osteointegration, the hydroxyapatite film may also increase the corrosion protection of the biomaterial.

  7. Hydroxyapatite-anatase-carbon nanotube nanocomposite coatings fabricated by electrophoretic codeposition for biomedical applications.

    PubMed

    Zhang, Bokai; Kwok, Chi Tat

    2011-10-01

    In order to eliminate micro-cracks in the monolithic hydroxyapatite (HA) and composite hydroxyapatite/carbon nanotube (HA/CNT) coatings, novel HA/TiO(2)/CNT nanocomposite coatings on Ti6Al4V were attempted to fabricate by a single-step electrophoretic codeposition process for biomedical applications. The electrophoretically deposited layers with difference contents of HA, TiO(2) (anatase) and CNT nanoparticles were sintered at 800°C for densification with thickness of about 7-10 μm. A dense and crack-free coating was achieved with constituents of 85 wt% HA, 10 wt% TiO(2) and 5 wt% CNT. Open-circuit potential measurements and cyclic potentiodynamic polarization tests were used to investigate the electrochemical corrosion behavior of the coatings in vitro conditions (Hanks' solution at 37°C). The HA/TiO(2)/CNT coatings possess higher corrosion resistance than that of the Ti6Al4V substrate as reflected by nobler open circuit potential and lower corrosion current density. In addition, the surface hardness and adhesion strength of the HA/TiO(2)/CNT coatings are higher than that of the monolithic HA and HA/CNT coatings without compromising their apatite forming ability. The enhanced properties were attributed to the nanostructure of the coatings with the appropriate TiO(2) and CNT contents for eliminating micro-cracks and micro-pores.

  8. A novel thermo-sensitive hydrogel based on thiolated chitosan/hydroxyapatite/beta-glycerophosphate.

    PubMed

    Liu, Xujie; Chen, Yan; Huang, Qianli; He, Wei; Feng, Qingling; Yu, Bo

    2014-09-22

    In order to get a water-soluble in situ gel-forming system, a thiolated chitosan, chitosan-4-thio-butylamidine (CS-TBA) conjugate was synthesized and used to replace the unmodified chitosan in the application of the in situ gel-forming system. A novel thermo-sensitive hydrogel was prepared based on CS-TBA/hydroxyapatite (HA)/beta-glycerophosphate disodium (β-GP). The gel formation, rheological properties, morphology, degradation, cytotoxicity, as well as protein release process of the novel gel system were investigated in this study. The CS-TBA/HA/β-GP gel showed a higher storage modulus (G') and loss modulus (G″) and a decreased bovine serum albumin (BSA) release rate which was maintained the protein release for a longer time compared with the unmodified chitosan (CS)/HA/β-GP gel, due to the existence of thiol groups and/or disulfide bonds. The CS-TBA/HA/β-GP gel has a porous structure with a uniform distribution of nano-hydroxyapatite, an appropriate degradation rate and low cytotoxicity, showing potential applications in drug delivery and tissue engineering. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Antibacterial Property of Cold-Sprayed HA-Ag/PEEK Coating

    NASA Astrophysics Data System (ADS)

    Sanpo, Noppakun; Tan, Meng Lu; Cheang, Philip; Khor, K. A.

    2009-03-01

    The antibacterial behavior of HA-Ag (silver-doped hydroxyapatite) nanopowder and their composite coatings were investigated against Escherichia coli (DH5α). HA-Ag nanopowder and PEEK (poly-ether-ether-ketone)-based HA-Ag composite powders were synthesized using in-house powder processing techniques. Bacteria culture assay of HA-Ag nanopowder and their composite powders displayed excellent bacteriostatic activity against E. coli. The antibacterial activity increased with increasing concentration of HA-Ag nanoparticle in these composite powders. These nanocomposite powders were subsequently used as feedstock to generate antibacterial coatings via cold spray technology. The ratios of HA-Ag to PEEK in their composite powders were 80:20, 60:40, 40:60, and 20:80 (wt.%). Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out using FESEM/EDX and XRD. Antibacterial nanocomposite HA-Ag/PEEK coatings were successfully deposited using cold spraying parameters of 11-12 bars at preheated air temperature between 150 and 160 °C. These as-sprayed coatings of HA-Ag/PEEK composite powders comprising varying HA-Ag and PEEK ratios retained their inherent antibacterial property as verified from bacterial assay. The results indicated that the antibacterial activity increased with increasing HA-Ag nanopowder concentration in the composite powder feedstock and cold-sprayed coating.

  10. Invitro Evaluation of Fluoride Release from Hydroxyapatite Reinforced Glass Ionomer with or without Protective Coating

    PubMed Central

    Nandlal, Bhojraj

    2016-01-01

    Introduction Glass Ionomer Cement (GIC) is well known for its fluoride releasing property but has its own drawbacks of poor mechanical properties, sensitivity to initial desiccation and moisture contamination. To overcome these, search led to the reinforcement of hydroxyapatite and application of surface coating agent but their effect on fluoride release is still not clear. Aim To evaluate and compare the release of fluoride from Hydroxyapatite Reinforced Glass Ionomer (HA-GIC) with and without protective coating. Materials and Methods Specimens were prepared as follows- Eight percent by weight conventional glass ionomer was replaced by hydroxyapatite powder (HA) and an indigenous product was prepared (HA-GIC). This powder was mixed with liquid of conventional GIC and allowed to set, then G coat plus coating agent was applied in surface coated group and light cured. Fluoride release of the sample was measured every 24 hrs for seven days and weekly from 7th to 21st day using combination ion selective electrode. Results Mean values clearly reveal a significant decrease in the fluoride release from day 1 to day 21 for both the groups. Results of repeated measure ANOVA revealed statistically significant difference between two groups (p <0.001). Conclusion Coating the hydroxyapatite reinforced glass ionomer will allow for slow and steady release of fluoride for a long period of time into oral environment. PMID:27190957

  11. Nanoporous hydroxyapatite/sodium titanate bilayer on titanium implants for improved osteointegration.

    PubMed

    Carradò, A; Perrin-Schmitt, F; Le, Q V; Giraudel, M; Fischer, C; Koenig, G; Jacomine, L; Behr, L; Chalom, A; Fiette, L; Morlet, A; Pourroy, G

    2017-03-01

    The aim of this study was to improve the strength and quality of the titanium-hydroxyapatite interface in order to prevent long-term failure of the implanted devices originating from coating delamination and to test it in an in-vivo model. Ti disks and dental commercial implants were etched in Kroll solution. Thermochemical treatments of the acid-etched titanium were combined with sol-gel hydroxyapatite (HA) coating processes to obtain a nanoporous hydroxyapatite/sodium titanate bilayer. The sodium titanate layer was created by incorporating sodium ions onto the Ti surface during a NaOH alkaline treatment and stabilized using a heat treatment. HA layer was added by dip-coating in a sol-gel solution. The bioactivity was assessed in vitro with murine MC3T3-E1 and human SaOs-2 cells. Functional and histopathological evaluations of the coated Ti implants were performed at 22, 34 and 60days of implantation in a dog lower mandible model. Nanoporous hydroxyapatite/sodium titanate bilayer on titanium implants was sensitive neither to crack propagation nor to layer delamination. The in vitro results on murine MC3T3-E1 and human SaOs-2 cells confirm the advantage of this coating regarding the capacity of cell growth and differentiation. Signs of progressive bone incorporation, such as cancellous bone formed in contact with the implant over the existing compact bone, were notable as early as day 22. Overall, osteoconduction and osteointegration mean scores were higher for test implants compared to the controls at 22 and 34 days. Nanoporous hydroxyapatite/sodium titanate bilayer improves the in-vivo osteoconduction and osteointegration. It prevents the delamination during the screwing and it could increase HA-coated dental implant stability without adhesive failures. The combination of thermochemical treatments with dip coating is a low-cost strategy. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. Hydroxyapatite, fluor-hydroxyapatite and fluorapatite produced via the sol-gel method: dissolution behaviour and biological properties after crystallisation.

    PubMed

    Tredwin, Christopher J; Young, Anne M; Abou Neel, Ensanya A; Georgiou, George; Knowles, Jonathan C

    2014-01-01

    Hydroxyapatite (HA), fluor-hydroxyapatite (FHA) with varying levels of fluoride ion substitution and fluorapatite (FA) were synthesised by the sol-gel method as possible implant coating or bone-grafting materials. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride were incorporated for the preparation of the FHA and FA sol-gels. After heating and powdering the sol-gels, dissolution behaviour was assessed using ion chromatography to measure Ca(2+) and PO4 (3-) ion release. Biological behaviour was assessed using cellular proliferation with human osteosarcoma cells and alamarBlue™ assay. Statistical analysis was performed with a two way analysis of variance and post hoc testing with a Bonferroni correction. Increasing fluoride substitution into an apatite structure decreased the dissolution rate. Increasing the firing temperature of the HA, FHA and FA sol-gels up to 1,000 °C decreased the dissolution rate. There was significantly higher cellular proliferation on highly substituted FHA and FA than on HA or Titanium. The properties of an implant coating or bone grafting material can be tailored to meet specific requirements by altering the amount of fluoride that is incorporated into the original apatite structure. The dissolution behaviour can further be altered by the temperature at which the sol-gel is fired.

  13. Preparation and characterization of carbon nanofibrous/hydroxyapatite sheets for bone tissue engineering.

    PubMed

    Abd El-Aziz, A M; El Backly, Rania M; Taha, Nahla A; El-Maghraby, Azza; Kandil, Sherif H

    2017-07-01

    Critical size bone defects are orthopedic defects that will not heal without intervention or that will not completely heal over the natural life time of the animal. Although bone generally has the ability to regenerate completely however, critical defects require some sort of scaffold to do so. In the current study we proposed a method to obtain a carbon nanofibrous/Hydroxyapatite (HA) bioactive scaffold. The carbon nanofibrous (CNF) nonwoven fabrics were obtained by the use of the electrospinning process of the polymeric solution of poly acrylonitrile "PAN" and subsequent stabilization and carbonization processes. The CNFs sheets were functionalized by both hydroxyapatite (HA) and bovine serum albumin (BSA). The HA was added to the electrospun solution, but in case of (BSA), it was adsorbed after the carbonization process. The changes in the properties taking place in the precursor sheets were investigated using the characterization methods (SEM, FT-IR, TGA and EDX). The prepared materials were tested for biocompatibility via subcutaneous implantation in New Zealand white rabbits. We successfully prepared biocompatible functionalized sheets, which have been modified with HA or HA and BSA. The sheets that were functionalized by both HA and BSA are more biocompatible with fewer inflammatory cells of (neutrophils and lymphocytes) than ones with only HA over the period of 3weeks. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Fabrication and mechanical evaluation of hydroxyapatite/oxide nano-composite materials.

    PubMed

    Mohamed, Khaled R; Beherei, Hanan H; El Bassyouni, Gehan T; El Mahallawy, Nahed

    2013-10-01

    In the current study, the semiconducting metal oxides such as nano-ZnO and SiO2 powders were prepared via sol-gel technique and conducted on nano-hydroxyapatite (nHA) which was synthesized by chemical precipitation. The properties of fabricated nano-structured composites containing different ratios of HA, ZnO and SiO2 were examined using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The effect of the variation of ratios between the three components on mechanical, microstructure and in-vitro properties was assessed to explore the possibility of enhancing these properties. The results proved that the mechanical properties exhibited an increment with increasing the ZnO content at the extent of HA. In-vitro study proved the formation and nucleation of apatite onto the surface of the fabricated composites after one week of immersion. It is concluded that HA composites containing SiO2 or SiO2/ZnO content had a suitable mechanical properties and ability to form apatite particles onto the composite surface. Based on bioactivity behavior, Si-HA is more bioactive than pure hydroxyapatite and nano-arrangements will provide an interface for better bone formation. Therefore, these nano-composites will be promising as bone substitutes especially in load bearing sites. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Hydroxyapatite degradation and biocompatibility

    NASA Astrophysics Data System (ADS)

    Wang, Haibo

    Hydroxyapatite (HA) is widely used as a bioactive ceramics since it forms a chemical bonding to bone. The disadvantage of this material is its poor mechanical properties. HA can be degraded in body, which is the reason for its bioactivity, but too fast degradation rate could cause negative effects, such as macrophage present, particle generation, and even implant clinical failure. HA degradation rate will be greatly changed under many conditions: purity, HA form (i.e. bulk form, porous form, coating, or HA/polymer composites), microstructure, implant site, body conditions, etc. Although much work has been done in HA properties and application areas, the HA degradation behavior and mechanism under these different conditions are still not clear. In this research, three aspects of HA degradation have been studied: (1) Two very common impurities---Tri-Calcium Phosphate (TCP) and Calcium Oxide and their influences on HA degradation in vitro and in vivo, (2) influence of HA/polymer composite form on HA degradation, (3) HA material particle generation and related mechanism. From the in vitro and in vivo tests on bulk HA disks with various Ca/P ratios, HA degradation can clearly be found. The degradation level is different in different Ca/P ratio samples as well as in different test environments. In same test environment, non-stoichiometric HA samples have higher degradation rate than stoichiometric HA. HA/PMMA composite design successfully intensifies HA degradation both in vitro and in vivo. Grain boundary damage can be found on in vivo test samples, which has not been clearly seen on bulk HA degraded surface. HA particle generation is found in in vitro and in vivo HA/PMMA composite surface and in vivo bulk HA surface. Sintering temperature and time does affect HA grain size, and this affect HA degradation rate. Intergranular fracture is found in a several micron zone close to the Ca/P ratio 1.62 and 1.67 sample degraded surfaces. At Ca/P ratio greater than 1.667, after

  16. Study of BSA protein adsorption/release on hydroxyapatite nanoparticles

    NASA Astrophysics Data System (ADS)

    Swain, Sanjaya Kumar; Sarkar, Debasish

    2013-12-01

    Three different spherical, rod and fibrous morphologies of hydroxyapatite (HA) nanoparticles have been prepared through control over the processing parameters like temperature, pH and Ca:P ratio. Protein adsorption/release with respect to HA nanoparticle morphologies are investigated using model protein bovine serum albumin (BSA). BSA adsorption on HA nanoparticles follows Langmuir adsorption isotherm. Thermal analysis and FT-IR spectrum confirms the BSA adhesion and retention of their secondary structure. High surface area with high Ca:P ratio nanorod adsorbs relatively more amount (28 mg BSA/gm of nanorod HA) of BSA within 48 h in comparison with counterpart fibroid and spherical morphologies. Slow and steady BSA release (75 wt% of adsorbed BSA in 96 h) from nanorod HA is found as futuristic drug delivery media.

  17. Hydroxyapatite grafted carbon nanotubes and graphene nanosheets: Promising bone implant materials

    NASA Astrophysics Data System (ADS)

    Oyefusi, Adebola; Olanipekun, Opeyemi; Neelgund, Gururaj M.; Peterson, Deforest; Stone, Julia M.; Williams, Ebonee; Carson, Laura; Regisford, Gloria; Oki, Aderemi

    2014-11-01

    In the present study, hydroxyapatite (HA) was successfully grafted to carboxylated carbon nanotubes (CNTs) and graphene nanosheets. The HA grafted CNTs and HA-graphene nanosheets were characterized using FT-IR, TGA, SEM and X-ray diffraction. The HA grafted CNTs and graphene nanosheets (CNTs-HA and Gr-HA) were further used to examine the proliferation and differentiation rate of temperature-sensitive human fetal osteoblastic cell line (hFOB 1.19). Total protein assays and western blot analysis of osteocalcin expression were used as indicators of cell proliferation and differentiation. Results indicated that hFOB 1.19 cells proliferate and differentiate well in treatment media containing CNTs-HA and graphene-HA. Both CNTs-HA and graphene-HA could be promising nanomaterials for use as scaffolds in bone tissue engineering.

  18. Direct and ultrasonic measurements of macroscopic piezoelectricity in sintered hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Tofail, S. A. M.; Haverty, D.; Cox, F.; Erhart, J.; Hána, P.; Ryzhenko, V.

    2009-03-01

    Macroscopic piezoelectricity in hydroxyapatite (HA) ceramic was measured by a direct quasistatic method and an ultrasonic interference technique. The effective symmetry of polycrystalline aggregate was established and a detailed theoretical analysis was carried out to determine by these two methods the shear piezoelectric coefficient, d14, of HA. Piezoelectric nature of HA was proved qualitatively although a specific quantitative value for the d14 coefficient could not be established. Ultrasound method was also employed to anisotropic elastic constants, which agreed well with those measured from the first principles.

  19. Mechanical properties of natural chitosan/hydroxyapatite/magnetite nanocomposites for tissue engineering applications.

    PubMed

    Heidari, Fatemeh; Razavi, Mehdi; E Bahrololoom, Mohammad; Bazargan-Lari, Reza; Vashaee, Daryoosh; Kotturi, Hari; Tayebi, Lobat

    2016-08-01

    Chitosan (CS), hydroxyapatite (HA), and magnetite (Fe3O4) have been broadly employed for bone treatment applications. Having a hybrid biomaterial composed of the aforementioned constituents not only accumulates the useful characteristics of each component, but also provides outstanding composite properties. In the present research, mechanical properties of pure CS, CS/HA, CS/HA/magnetite, and CS/magnetite were evaluated by the measurements of bending strength, elastic modulus, compressive strength and hardness values. Moreover, the morphology of the bending fracture surfaces were characterized using a scanning electron microscope (SEM) and an image analyzer. Studies were also conducted to examine the biological response of the human Mesenchymal Stem Cells (hMSCs) on different composites. We conclude that, although all of these composites possess in-vitro biocompatibility, adding hydroxyapatite and magnetite to the chitosan matrix can noticeably enhance the mechanical properties of the pure chitosan. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Facile synthesis of biphasic calcium phosphate microspheres with engineered surface topography for controlled delivery of drugs and proteins.

    PubMed

    Zarkesh, Ibrahim; Ghanian, Mohammad Hossein; Azami, Mahmoud; Bagheri, Fatemeh; Baharvand, Hossein; Mohammadi, Javad; Eslaminejad, Mohamadreza Baghaban

    2017-09-01

    Biphasic calcium phosphate (BCP) microspheres are of great interest due to their high stability and osteoinductive properties at specific compositions. However, the need for optimal performance at a unique composition limits their flexibility for tuning drug release by modulation of bulk properties and presents the question of engineering surface topography as an alternative. It is necessary to have a facile method to control surface topography at a defined bulk composition. Here, we have produced BCP microspheres with different surface topographies that have the capability to be used as tunable drug release systems. We synthesized calcium deficient hydroxyapatite (CDHA) microparticles by precipitating calcium and phosphate ions onto ethylenediaminetetraacetic acid (EDTA) templates. The morphology and surface topography of CDHA microparticles were controlled using process parameters, which governed nucleation and growth. These parameters included template concentration, heat rate, and stirring speed. Under low heat rate and static conditions, we could obtain spherical microparticles with long and short nanosheets on their surfaces at low and high EDTA concentrations, respectively. These nanostructured microspheres were subsequently crystallized by thermal treatment to produce EDTA-free BCP microspheres with intact morphology. These biocompatible BCP microspheres were highly effective in loading and prolonged release of both small molecule [dexamethasone (Dex)] and protein [bovine serum albumin (BSA)] models. This strategy has enabled us to control the surface topography of BCP microspheres at defined compositions and holds tremendous promise for drug delivery and tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Radiochemistry, pre-clinical studies and first clinical investigation of 90Y-labeled hydroxyapatite (HA) particles prepared utilizing 90Y produced by (n,γ) route.

    PubMed

    Vimalnath, K V; Chakraborty, Sudipta; Rajeswari, A; Sarma, H D; Nuwad, Jitendra; Pandey, Usha; Kamaleshwaran, K; Shinto, Ajit; Dash, Ashutosh

    2015-05-01

    The scope of using no carrier added (NCA) (90)Y [T(1/2) = 64.1 h, Eβ(max) = 2.28 MeV] obtained from (90)Sr/(90)Y generator in radiation synovectomy (RSV) is widely accepted. In the present study, the prospect of using (90)Y produced by (n,γ) route in a medium flux research reactor for use in RSV was explored. Yttrium-90 was produced by thermal neutron irradiation of Y(2)O(3) target at a neutron flux of ~1×10(14) n/cm(2).s for 14 d. The influence of various experimental parameters were systematically investigated and optimized to arrive at the most favorable conditions for the formulation of (90)Y labeled hydroxyapatite (HA) using HA particles of 1-10 μm size range. An optimized kit formulation strategy was developed for convenient one-step compounding of (90)Y-HA, which is easily adaptable at hospital radiopharmacy. The pre-clinical biological evaluation of (90)Y-HA particles was studied by carrying out biodistribution and bioluminiscence imaging studies in Wistar rats. The first clinical investigation using the radiolabeled preparation was performed on a patient suffering from chronic arthritis in knee joint by administering 185 MBq (90)Y-HA formulated at the hospital radiopharmacy deploying the proposed strategy. Yttrium-90 was produced with a specific activity of 851 ± 111 MBq/mg and radionuclidic purity of 99.95 ± 0.02%. (90)Y-labeled HA particles (185 ± 10 MBq doses) were formulated in high radiochemical purity (>99%) and excellent in vitro stability. The preparation showed promising results in pre-clinical studies carried out in Wistar rats. The preliminary results of the first clinical investigation of (90)Y-HA preparation in a patient with rheumatoid arthritis in knee joints demonstrated the effectiveness of the formulation prepared using (90)Y produced via (n,γ) route in the management of the disease. The studies revealed that effective utilization of (90)Y produced via (n,γ) route in a medium flux research reactor coupled with the developed

  2. Distributed vasculogenesis from modular agarose-hydroxyapatite-fibrinogen microbeads.

    PubMed

    Rioja, Ana Y; Daley, Ethan L H; Habif, Julia C; Putnam, Andrew J; Stegemann, Jan P

    2017-06-01

    Critical limb ischemia impairs circulation to the extremities, causing pain, disrupted wound healing, and potential tissue necrosis. Therapeutic angiogenesis seeks to repair the damaged microvasculature directly to restore blood flow. In this study, we developed modular, micro-scale constructs designed to possess robust handling qualities, allow in vitro pre-culture, and promote microvasculature formation. The microbead matrix consisted of an agarose (AG) base to prevent aggregation, combined with cell-adhesive components of fibrinogen (FGN) and/or hydroxyapatite (HA). Microbeads encapsulating a co-culture of human umbilical vein endothelial cells (HUVEC) and fibroblasts were prepared and characterized. Microbeads were generally 80-100µm in diameter, and the size increased with the addition of FGN and HA. Addition of HA increased the yield of microbeads, as well as the homogeneity of distribution of FGN within the matrix. Cell viability was high in all microbead types. When cell-seeded microbeads were embedded in fibrin hydrogels, HUVEC sprouting and inosculation between neighboring microbeads were observed over seven days. Pre-culture of microbeads for an additional seven days prior to embedding in fibrin resulted in significantly greater HUVEC network length in AG+HA+FGN microbeads, as compared to AG, AG+HA or AG+FGN microbeads. Importantly, composite microbeads resulted in more even and widespread endothelial network formation, relative to control microbeads consisting of pure fibrin. These results demonstrate that AG+HA+FGN microbeads support HUVEC sprouting both within and between adjacent microbeads, and can promote distributed vascularization of an external matrix. Such modular microtissues may have utility in treating ischemic tissue by rapidly re-establishing a microvascular network. Critical limb ischemia (CLI) is a chronic disease that can lead to tissue necrosis, amputation, and death. Cell-based therapies are being explored to restore blood flow and

  3. Preparation and properties of in-situ growth of carbon nanotubes reinforced hydroxyapatite coating for carbon/carbon composites.

    PubMed

    Liu, Shoujie; Li, Hejun; Su, Yangyang; Guo, Qian; Zhang, Leilei

    2017-01-01

    Carbon nanotubes (CNTs) possess excellent mechanical properties for their role playing in reinforcement as imparting strength to brittle hydroxyapatite (HA) bioceramic coating. However, there are few reports relating to the in-situ grown carbon nanotubes reinforced hydroxyapatite (CNTs-HA) coating. Here we demonstrate the potential application in reinforcing biomaterials by an attempt to use in-situ grown of CNTs strengthen HA coating, using a combined method composited of injection chemical vapor deposition (ICVD) and pulsed electrodeposition. The microstructure, phases and chemical compositions of CNTs-HA coatings were characterized by various advanced methods. The scanning electron microscopy (SEM) images indicated that CNTs-HA coatings avoided the inhomogeneous dispersion of CNTs inside HA coating. The result show that the interfacial shear strength between CNTs-HA coating and the C/C composite matrix reaches to 12.86±1.43MPa. Potenitodynamic polarization and electrochemical impedance spectroscopy (EIS) studies show that the content of CNTs affects the corrosion resistance of CNTs-HA coating. Cell culturing and simulated body fluid test elicit the biocompatibility with living cells and bioactivity of CNTs-HA coatings, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Mechanical, thermal, rheological and morphological behaviour of irradiated PP/HA composites

    NASA Astrophysics Data System (ADS)

    Ramírez, C.; Albano, C.; Karam, A.; Domínguez, N.; Sánchez, Y.; González, G.

    2005-07-01

    Hydroxyapatite (HA) reinforced polypropylene (PP) composites are being developed as bone graft materials. In this research, the effect of γ irradiation on mechanical, rheological, thermal and morphological behaviour of PP-HA composites was studied. The melt flow index of polymer increased markedly when it was exposed to radiation. This is indicative of chain scission reaction as the predominant process. During the tensile testing, the composites exhibited brittle behaviour, showing no fluency point. Elongation at break showed a tendency to decrease with the increase in radiation dose while stress at break did not show significant variation with radiation dose. High HA content (>20%) and radiation dose (25 kGy) had significant influence on thermal stability.

  5. Novel Development of Phosphate Treated Porous Hydroxyapatite.

    PubMed

    Doi, Kazuya; Abe, Yasuhiko; Kobatake, Reiko; Okazaki, Yohei; Oki, Yoshifumi; Naito, Yoshihito; Prananingrum, Widyasri; Tsuga, Kazuhiro

    2017-12-08

    Phosphoric acid-etching treatment to the hydroxyapatite (HA) surface can modify the solubility calcium structure. The aim of the present study was to develop phosphate treated porous HA, and the characteristic structures and stimulation abilities of bone formation were evaluated to determine its suitability as a new type of bone graft material. Although the phosphoric acid-etching treatment did not alter the three-dimensional structure, a micrometer-scale rough surface topography was created on the porous HA surface. Compared to porous HA, the porosity of phosphate treated porous HA was slightly higher and the mechanical strength was lower. Two weeks after placement of the cylindrical porous or phosphate treated porous HA in a rabbit femur, newly formed bone was detected in both groups. At the central portion of the bone defect area, substantial bone formation was detected in the phosphate treated porous HA group, with a significantly higher bone formation ratio than detected in the porous HA group. These results indicate that phosphate treated porous HA has a superior surface topography and bone formation abilities in vivo owing to the capacity for both osteoconduction and stimulation abilities of bone formation conferred by phosphoric acid etching.

  6. Novel Development of Phosphate Treated Porous Hydroxyapatite

    PubMed Central

    Doi, Kazuya; Abe, Yasuhiko; Kobatake, Reiko; Okazaki, Yohei; Oki, Yoshifumi; Naito, Yoshihito; Prananingrum, Widyasri; Tsuga, Kazuhiro

    2017-01-01

    Phosphoric acid-etching treatment to the hydroxyapatite (HA) surface can modify the solubility calcium structure. The aim of the present study was to develop phosphate treated porous HA, and the characteristic structures and stimulation abilities of bone formation were evaluated to determine its suitability as a new type of bone graft material. Although the phosphoric acid-etching treatment did not alter the three-dimensional structure, a micrometer-scale rough surface topography was created on the porous HA surface. Compared to porous HA, the porosity of phosphate treated porous HA was slightly higher and the mechanical strength was lower. Two weeks after placement of the cylindrical porous or phosphate treated porous HA in a rabbit femur, newly formed bone was detected in both groups. At the central portion of the bone defect area, substantial bone formation was detected in the phosphate treated porous HA group, with a significantly higher bone formation ratio than detected in the porous HA group. These results indicate that phosphate treated porous HA has a superior surface topography and bone formation abilities in vivo owing to the capacity for both osteoconduction and stimulation abilities of bone formation conferred by phosphoric acid etching. PMID:29292788

  7. Cytotoxicity and genotoxicity property of hydroxyapatite-mullite eluates.

    PubMed

    Kalmodia, Sushma; Sharma, Vyom; Pandey, Alok K; Dhawan, Alok; Basu, Bikramjit

    2011-02-01

    Long-term biomedical applications of implant materials may cause osteolysis, aseptic losing and toxicity. Therefore, we investigated the cytotoxic and genotoxic potential of hydroxyapatite (HA) mullite eluates in L929 mouse fibroblast cells. The spark plasma sintered HA-20% mullite biocomposite (HA20M) were ground using mortar and pestle as well as ball milling. The cells were exposed for 6 h to varying concentrations (10, 25, 50, 75 and 100%) of the eluates of HA-20% mullite (87 nm), HA (171 nm) and mullite (154 nm). The scanning electron microscopy and MTT assay revealed the concentration dependent toxicity of H20M eluate at and above 50%. The analysis of the DNA damaging potential of HA, mullite and HA20M eluates using Comet assay demonstrated a significant DNA damage by HA20M which was largely related to the presence of mullite. The results collectively demonstrate the cytotoxic and genotoxic potential of HA20M eluate in L929 cells is dependent on particle size, concentration and composition.

  8. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yao, Aihua, E-mail: aihyao@126.com; Ai, Fanrong; Liu, Xin

    Hollow hydroxyapatite microspheres, consisting of a hollow core and a porous shell, were prepared by converting Li{sub 2}O-CaO-B{sub 2}O{sub 3} glass microspheres in dilute phosphate solution at 37 {sup o}C. The results confirmed that Li{sub 2}O-CaO-B{sub 2}O{sub 3} glass was transformed to hydroxyapatite without changing the external shape and dimension of the original glass object. Scanning electron microscopy images showed the shell wall of the microsphere was built from hydroxyapatite particles, and these particles spontaneously align with one another to form a porous sphere with an interior cavity. Increase in phosphate concentration resulted in an increase in the reaction rate,more » which in turn had an effect on shell wall structure of the hollow hydroxyapatite microsphere. For the Li{sub 2}O-CaO-B{sub 2}O{sub 3} glass microspheres reacted in low-concentration K{sub 2}HPO{sub 4} solution, lower reaction rate and a multilayered microstructure were observed. On the other hand, the glass microspheres reacted in higher phosphate solution converted more rapidly and produced a single hydroxyapatite layer. Furthermore, the mechanism of forming hydroxyapatite hollow microsphere was described.« less

  9. A new approach for the one-step synthesis of bioactive PS vs. PMMA silica hybrid microspheres as potential drug delivery systems.

    PubMed

    Angelopoulou, A; Efthimiadou, E K; Boukos, N; Kordas, G

    2014-05-01

    In this work, hybrid microspheres were prepared in a two-step process combining the emulsifier free-emulsion polymerization and the sol-gel coating method. In the first step, polystyrene (St) and poly(methyl methacrylate) (PMMA) microspheres were prepared as sacrificial template and in the second step a silanol shell was fabricated. The functionalized surface of the hybrid microspheres by silane analogs (APTES, TEOS) resulted in enhanced effects. The hollow microspheres were resulted either in an additional step by template dissolution and/or during the coating process. The microspheres' surface interactions and the size distribution were optimized by treatment in simulated body fluids, which resulted in the in vitro prediction of bioactivity. The bioassay test indicated that the induced hydroxyapatite resembled in structure to naturally occurring bone apatite. The drug doxorubicin (DOX) was used as a model entity for the evaluation of drug loading and release. The drug release study was performed in two different pH conditions, at acidic (pH=4.5) close to cancer cell environment and at slightly basic pH (pH=7.4) resembling the orthopedic environment. The results of the present study indicated promising hybrid microspheres for the potential application as drug delivery vehicles, for dual orthopedic functionalities in bone defects, bone inflammation, bone cancer and bone repair. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Hydroxyapatite grafted carbon nanotubes and graphene nanosheets: promising bone implant materials.

    PubMed

    Oyefusi, Adebola; Olanipekun, Opeyemi; Neelgund, Gururaj M; Peterson, Deforest; Stone, Julia M; Williams, Ebonee; Carson, Laura; Regisford, Gloria; Oki, Aderemi

    2014-11-11

    In the present study, hydroxyapatite (HA) was successfully grafted to carboxylated carbon nanotubes (CNTs) and graphene nanosheets. The HA grafted CNTs and HA-graphene nanosheets were characterized using FT-IR, TGA, SEM and X-ray diffraction. The HA grafted CNTs and graphene nanosheets (CNTs-HA and Gr-HA) were further used to examine the proliferation and differentiation rate of temperature-sensitive human fetal osteoblastic cell line (hFOB 1.19). Total protein assays and western blot analysis of osteocalcin expression were used as indicators of cell proliferation and differentiation. Results indicated that hFOB 1.19 cells proliferate and differentiate well in treatment media containing CNTs-HA and graphene-HA. Both CNTs-HA and graphene-HA could be promising nanomaterials for use as scaffolds in bone tissue engineering. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Preparation and Characterization of Hydroxyapatite-Silica Composite Nanopowders

    NASA Astrophysics Data System (ADS)

    Latifi, S. M.; Fathi, M. H.; Golozar, M. A.

    One of the most important objectives in the field of biomaterials science and engineering is development of new materials as bone substitutes. Silica (SiO2) has an important role in the biomineralization and biological responses. The aim of this research was to prepare and characterize hydroxyapatite-silica (HA-SiO2) composite nanopowder with different content of silica. Hydroxyapatite-silica composite nanopowders with 20 and 40 wt% silica were prepared using a sol-gel method at 600°C with phosphoric pentoxide and calcium nitrate tetrahydrate as a source of hydroxyapatite; also, tetraethylorthosilicate and methyltriethoxisilane as a source of silica. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques were used for characterization and evaluation of the products. The results indicated the presence of nanocrystalline hydroxyapatite phase beside amorphous silica phase in prepared composite nanopowders. Moreover, by increasing the content of silica in composite nanopowders, the crystallinity will be decreased,and the ability of the product as a bone substitute material might be controlled by changing the content of the ingredients and subsequently its structure.

  12. Synthesis of hydroxyapatite/multi-walled carbon nanotubes for the removal of fluoride ions from solution

    NASA Astrophysics Data System (ADS)

    Ruan, Zhongyuan; Tian, Yaxi; Ruan, Jifu; Cui, Guijia; Iqbal, Kanwal; Iqbal, Anam; Ye, Herui; Yang, Zhangzhong; Yan, Shiqiang

    2017-08-01

    A novel composite material, hydroxyapatite (HA)-multi-walled carbon nanotubes (MWCNTs), was prepared using a simple in-situ sol-gel method, and was used for the first time to remove fluoride from water. The novel HA-MWCNTs were characterized using TEM, FT-IR, BET and XRD analysis. The TEM and SAED results revealed that the MWCNTs were uniformly encapsulated by hydroxyapatite nanoparticles. The synthesized HA-MWCNTs had a high specific surface area (180.504 m2 g-1), with an average pore width (14.607 nm) and pore volume (0.774 cm3 g-1), which produced a defluoridation capacity (DC) of 30.22 mgF- g-1. This value was greater than unmodified hydroxyapatite (HA), which exhibited a larger specific surface area (172.233 m2 g-1) and an excellent DC of 17.80 mgF- g-1. A number of pertinent parameters that could affect the defluoridation performance of the HA/MWCNTs including weight ratios of the two key materials, solution pH and competing anions were carefully and comprehensively examined. It was found that the adsorption results followed the Langmuir and Freundlich isotherm model, and the sorption kinetics of the F- appeared to exhibit a pseudo second order. Moreover, the adsorption reaction was spontaneous and endothermic and appeared to exhibit a higher initial adsorption rate. This reaction appeared to occur result from both anion exchange and electrostatic interactions. When the HA-MWCNTs (MH6) were at an adsorbent dose of 2.0 g L-1, they were able to decrease the fluoride concentration of actual nuclear industry wastewater from 8.79 mg L-1 to about 0.25 mg L-1 (97.15% removal efficiency). The experimental results of this study showed that the HA-MWCNTs composites have application potential for the removal of fluoride ions from wastewater.

  13. Hydroxyapatite, fluor-hydroxyapatite and fluorapatite produced via the sol-gel method: bonding to titanium and scanning electron microscopy.

    PubMed

    Tredwin, Christopher J; Georgiou, George; Kim, Hae-Won; Knowles, Jonathan C

    2013-05-01

    Hydroxyapatite (HA), fluor-hydroxyapatite (FHA) with varying levels of fluoride ion substitution and fluorapatite (FA) production has been characterised and optimised by the sol-gel method and the dissolution and biological properties of these materials were investigated. It was the objective of this study to investigate the potential bond strength and interaction of these materials with titanium. HA, FHA and FA were synthesised by a sol-gel method. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride (NH4F) were incorporated for the preparation of the FHA and FA sol-gels. Using a spin coating technique the sol-gels were coated onto commercially pure titanium disks and crystallised at various temperatures. Using scanning electron microscopy (SEM) and elemental analysis, the surface characteristics, coating thickness and interaction of the Ti substrate and coating were investigated. The bond strengths of the coating to the Ti were investigated using an Instron Universal Load Testing Machine. Statistical analysis was performed with a two-way analysis of variance and post hoc testing with a Bonferroni correction. (1) Coating speed inversely influenced the coating thickness. (2) Increasing fluoride ion substitution and heating temperature significantly increased bond strength and (3) increasing fluoride ion substitution increased the coating thickness. FHA and FA synthesised using the sol-gel technique may offer a superior alternative to coating titanium implants with HA and plasma spraying. HA, FHA and FA materials synthesised by the sol-gel method may also have a use as bone grafting materials. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  14. Development of high strength hydroxyapatite for bone tissue regeneration using nanobioactive glass composites

    NASA Astrophysics Data System (ADS)

    Shrivastava, Pragya; Dalai, Sridhar; Sudera, Prerna; Sivam, Santosh Param; Vijayalakshmi, S.; Sharma, Pratibha

    2013-02-01

    With an increasing demand of biocompatible bone substitutes for the treatment of bone diseases and bone tissue regeneration, bioactive glass composites are being tested to improvise the osteoconductive as well as osteoinductive properties. Nanobioactive glass (nBG) composites, having composition of SiO2 70 mol%, CaO 26 mol % and P2O5 4 mol% were prepared by Freeze drying method using PEG-PPG-PEG co-polymer. Polymer addition improves the mechanical strength and porosity of the scaffold of nBG. Nano Bioactive glass composites upon implantation undergo specific reactions leading to the formation of crystalline hydroxyapatite (HA). This is tested in vitro using Simulated Body Fluid (SBF). This high strength hydroxyapatite (HA) layer acts as osteoconductive in cellular environment, by acting as mineral base of bones, onto which new bone cells proliferate leading to new bone formation. Strength of the nBG composites as well as HA is in the range of cortical and cancellous bone, thus proving significant for bone tissue regeneration substitutes.

  15. Osteoconductive hydroxyapatite coated PEEK for spinal fusion surgery

    NASA Astrophysics Data System (ADS)

    Hahn, Byung-Dong; Park, Dong-Soo; Choi, Jong-Jin; Ryu, Jungho; Yoon, Woon-Ha; Choi, Joon-Hwan; Kim, Jong-Woo; Ahn, Cheol-Woo; Kim, Hyoun-Ee; Yoon, Byung-Ho; Jung, In-Kwon

    2013-10-01

    Polyetheretherketone (PEEK) has attracted much interest as biomaterial for interbody fusion cages due to its similar stiffness to bone and good radio-transparency for post-op visualization. Hydroxyapatite (HA) coating stimulates bone growth to the medical implant. The objective of this work is to make an implant consisting of biocompatible PEEK with an osteoconductive HA surface for spinal or orthopedic applications. Highly dense and well-adhered HA coating was developed on medical-grade PEEK using aerosol deposition (AD) without thermal degradation of the PEEK. The HA coating had a dense microstructure with no cracks or pores, and showed good adhesion to PEEK at adhesion strengths above 14.3 MPa. The crystallinity of the HA coating was remarkably enhanced by hydrothermal annealing as post-deposition heat-treatment. In addition, in vitro and in vivo biocompatibility of PEEK, in terms of cell adhesion morphology, cell proliferation, differentiation, and bone-to-implant contact ratio, were remarkably enhanced by the HA coating through AD.

  16. Preparation of nano-hydroxyapatite particles with different morphology and their response to highly malignant melanoma cells in vitro

    NASA Astrophysics Data System (ADS)

    Li, Bo; Guo, Bo; Fan, Hongsong; Zhang, Xingdong

    2008-11-01

    To investigate the effects of nano-hydroxyapatite (HA) particles with different morphology on highly malignant melanoma cells, three kinds of HA particles with different morphology were synthesized and co-cultured with highly malignant melanoma cells using phosphate-buffered saline (PBS) as control. A precipitation method with or without citric acid addition as surfactant was used to produce rod-like hydroxyapatite (HA) particles with nano- and micron size, respectively, and a novel oil-in-water emulsion method was employed to prepare ellipse-like nano-HA particles. Particle morphology and size distribution of the as prepared HA powders were characterized by transmission electron microscope (TEM) and dynamic light scattering technique. The nano- and micron HA particles with different morphology were co-cultured with highly malignant melanoma cells. Immunofluorescence analysis and MTT assay were employed to evaluate morphological change of nucleolus and proliferation of tumour cells, respectively. To compare the effects of HA particles on cell response, the PBS without HA particles was used as control. The experiment results indicated that particle nanoscale effect rather than particle morphology of HA was more effective for the inhibition on highly malignant melanoma cells proliferation.

  17. Hydroxyapatite Nanoparticles as a Novel Gene Carrier

    NASA Astrophysics Data System (ADS)

    Zhu, S. H.; Huang, B. Y.; Zhou, K. C.; Huang, S. P.; Liu, F.; Li, Y. M.; Xue, Z. G.; Long, Z. G.

    2004-06-01

    Hydroxyapatite crystalline nanoparticles were created by a precipitation hydrothermal technique and the majority of crystal particles were in the size range of 40-60nm and exhibited a colloidal feature when suspended in water. The gastric cancer SGC-7901 cell line cells were cultivated in the presence of10-100 μg ml-1 hydroxyapatite nanoparticle suspension and verified by MTT evaluation for their biocompatibility in vitro. The agarose gel electrophoresis analysis demonstrated that the HA nanoparticles potentially adsorb the green fluorescence protein EGFP-N1 plasmid DNA at pH 2 and 7, but not at pH 12. The DNA-nanoparticle complexes transfected EGFP-N1 pDNA into SGC-7901 cells in vitro with the efficiency about 80% as referenced with Lipofectmine TM 2000. In vivo animal experiment revealed no acute toxic adverse effect 2weeks after tail vein injection into mice, and TEM examination demonstrated their biodistribution and expression within the cytoplasm and also a little in the nuclei of the liver, kidney and brain tissue cells. These results suggest that the HA nanoparticle is a promising material that can be used as gene carrier, vectors.

  18. [Nano-hydroxyapatite/collagen composite for bone repair].

    PubMed

    Feng, Qing-ling; Cui, Fu-zhai; Zhang, Wei

    2002-04-01

    To develop nano-hydroxyapatite/collagen (NHAC) composite and test its ability in bone repairing. NHAC composite was developed by biomimetic method. The composite showed some features of natural bone in both composition and microstructure. The minerals could contribute to 50% by weight of the composites in sheet form. The inorganic phase in the composite was carbonate-substituted hydroxyapatite (HA) with low crystallinity and nanometer size. HA precipitates were uniformly distributed on the type I collagen matrix without preferential orientation. The composite exhibited an isotropic mechanical behavior. However, the resistance of the composite to localized pressure could reach the lower limit of that of femur compacta. The tissue response to the NHAC composite implanted in marrow cavity was investigated. Knoop micro-hardness test was performed to compare the mechanical behavior of the composite and bone. At the interface of the implant and marrow tissue, solution-mediated dissolution and macrophage-mediated resorption led to the degradation of the composite, followed by interfacial bone formation by osteoblasts. The process of implant degradation and bone substitution was reminiscent of bone remodeling. The composite can be incorporated into bone metabolism instead of being a permanent implant.

  19. Antibacterial properties of Ag-doped hydroxyapatite layers prepared by PLD method

    NASA Astrophysics Data System (ADS)

    Jelínek, Miroslav; Kocourek, Tomáš; Jurek, Karel; Remsa, Jan; Mikšovský, Jan; Weiserová, Marie; Strnad, Jakub; Luxbacher, Thomas

    2010-12-01

    Thin hydroxyapatite (HA), silver-doped HA and silver layers were prepared using a pulsed laser deposition method. Doped layers were ablated from silver/HA targets. Amorphous and crystalline films of silver concentrations of 0.06 at.%, 1.2 at.%, 4.4 at.%, 8.3 at.% and 13.7 at.% were synthesized. Topology was studied using scanning electron microscopy and atomic force microscopy. Contact angle and zeta potential measurements were conducted to determine the wettability, surface free energy and electric surface properties. In vivo measurement (using Escherichia coli cells) of antibacterial properties of the HA, silver-doped HA and silver layers was carried out. The best antibacterial results were achieved for silver-doped HA layers of silver concentration higher than 1.2 at.%.

  20. Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications

    PubMed Central

    Wilcock, Caroline J.; Gentile, Piergiorgio; Hatton, Paul V.; Miller, Cheryl A.

    2017-01-01

    Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest regarding the use of bioinspired nanoscale hydroxyapatite (nHA). However, biological apatite is known to be calcium-deficient and carbonate-substituted with a nanoscale platelet-like morphology. Bioinspired nHA has the potential to stimulate optimal bone tissue regeneration due to its similarity to bone and tooth enamel mineral. Many of the methods currently used to fabricate nHA both in the laboratory and commercially, involve lengthy processes and complex equipment. Therefore, the aim of this study was to develop a rapid and reliable method to prepare high quality bioinspired nHA. The rapid mixing method developed was based upon an acid-base reaction involving calcium hydroxide and phosphoric acid. Briefly, a phosphoric acid solution was poured into a calcium hydroxide solution followed by stirring, washing and drying stages. Part of the batch was sintered at 1,000 °C for 2 h in order to investigate the products' high temperature stability. X-ray diffraction analysis showed the successful formation of HA, which showed thermal decomposition to β-tricalcium phosphate after high temperature processing, which is typical for calcium-deficient HA. Fourier transform infrared spectroscopy showed the presence of carbonate groups in the precipitated product. The nHA particles had a low aspect ratio with approximate dimensions of 50 x 30 nm, close to the dimensions of biological apatite. The material was also calcium deficient with a Ca:P molar ratio of 1.63, which like biological apatite is lower than the stoichiometric HA ratio of 1.67. This new method is therefore a reliable and far more convenient process for the manufacture of bioinspired nHA, overcoming the need for lengthy titrations and complex equipment. The resulting bioinspired HA product is suitable for use in a wide variety of medical and consumer health

  1. Rapid Mix Preparation of Bioinspired Nanoscale Hydroxyapatite for Biomedical Applications.

    PubMed

    Wilcock, Caroline J; Gentile, Piergiorgio; Hatton, Paul V; Miller, Cheryl A

    2017-02-23

    Hydroxyapatite (HA) has been widely used as a medical ceramic due to its good biocompatibility and osteoconductivity. Recently there has been interest regarding the use of bioinspired nanoscale hydroxyapatite (nHA). However, biological apatite is known to be calcium-deficient and carbonate-substituted with a nanoscale platelet-like morphology. Bioinspired nHA has the potential to stimulate optimal bone tissue regeneration due to its similarity to bone and tooth enamel mineral. Many of the methods currently used to fabricate nHA both in the laboratory and commercially, involve lengthy processes and complex equipment. Therefore, the aim of this study was to develop a rapid and reliable method to prepare high quality bioinspired nHA. The rapid mixing method developed was based upon an acid-base reaction involving calcium hydroxide and phosphoric acid. Briefly, a phosphoric acid solution was poured into a calcium hydroxide solution followed by stirring, washing and drying stages. Part of the batch was sintered at 1,000 °C for 2 h in order to investigate the products' high temperature stability. X-ray diffraction analysis showed the successful formation of HA, which showed thermal decomposition to β-tricalcium phosphate after high temperature processing, which is typical for calcium-deficient HA. Fourier transform infrared spectroscopy showed the presence of carbonate groups in the precipitated product. The nHA particles had a low aspect ratio with approximate dimensions of 50 x 30 nm, close to the dimensions of biological apatite. The material was also calcium deficient with a Ca:P molar ratio of 1.63, which like biological apatite is lower than the stoichiometric HA ratio of 1.67. This new method is therefore a reliable and far more convenient process for the manufacture of bioinspired nHA, overcoming the need for lengthy titrations and complex equipment. The resulting bioinspired HA product is suitable for use in a wide variety of medical and consumer health

  2. Experimental and numerical measurements of adhesion energies between PHEMA and PGLYMA with hydroxyapatite crystal.

    PubMed

    Youssefian, Sina; Liu, Pingsheng; Askarinejad, Sina; Shalchy, Faezeh; Song, Jie; Rahbar, Nima

    2015-07-16

    Synthetic orthopaedic materials consisting of a single bioinert polymeric material do not meet the complex biological and physical requirements of scaffold-guided bone tissue repair and regeneration. Of particular interest is the design of biocompatible hydrogel-hydroxyapatite composite bone substitutes with outstanding interfacial adhesion that would warranty the ability for the composite to withstand functional loadings without exhibiting brittle fractures during the dynamic guided tissue regeneration. For this purpose, the hydroxylated side chain of chemically cross-linked poly (2-hydroxyethyl methacrylate) (pHEMA) is substitute with a carboxylated side chain to make poly (glycerol methacrylate) (pGLYMA). Here, we carry out atomistic simulations and atomic force microscopy to predict and experimentally determine the interfacial adhesion energies of pHEMA and pGLYMA with the surface of single-crystalline hydroxyapatite (HA) whiskers. Both experimental and numerical results showed that pGLYMA has stronger adhesion forces with HA and may be used for preparing a high-affinity polymer-HA composite. The high adhesive interactions between pGLYMA and HA were found to be due to strong electrostatic energies.

  3. Effect of atmosphere on phase transformation in plasma-sprayed hydroxyapatite coatings during heat treatment.

    PubMed

    Chen, J; Tong, W; Cao, Y; Feng, J; Zhang, X

    1997-01-01

    The purpose of this study was to evaluate the effect of atmosphere on the phase transformation in hydroxyapatite (HA) coatings during heat treatment by varying the atmosphere in the furnace pipe. Heat treatment always increased the crystallinity of HA coatings regardless of the kind of atmosphere. Water molecules in atmosphere further promoted HA recrystallization during heat treatment. In a dry atmosphere, tricalcium phosphate (TCP) and tetracalcium phosphate (TTCP) were more stable than HA, so heat treatment could not convert them into HA. However, in a humid atmosphere, heat treatment would transform TCP and TTCP into HA by hydrolytic reactions.

  4. Preparation and corrosion resistance of magnesium phytic acid/hydroxyapatite composite coatings on biodegradable AZ31 magnesium alloy.

    PubMed

    Zhang, Min; Cai, Shu; Zhang, Feiyang; Xu, Guohua; Wang, Fengwu; Yu, Nian; Wu, Xiaodong

    2017-06-01

    In this work, a magnesium phytic acid/hydroxyapatite composite coating was successfully prepared on AZ31 magnesium alloy substrate by chemical conversion deposition technology with the aim of improving its corrosion resistance and bioactivity. The influence of hydroxyapatite (HA) content on the microstructure and corrosion resistance of the coatings was investigated. The results showed that with the increase of HA content in phytic acid solution, the cracks on the surface of the coatings gradually reduced, which subsequently improved the corrosion resistance of these coated magnesium alloy. Electrochemical measurements in simulated body fluid (SBF) revealed that the composite coating with 45 wt.% HA addition exhibited superior surface integrity and significantly improved corrosion resistance compared with the single phytic acid conversion coating. The results of the immersion test in SBF showed that the composite coating could provide more effective protection for magnesium alloy substrate than that of the single phytic acid coating and showed good bioactivity. Magnesium phytic acid/hydroxyapatite composite, with the desired bioactivity, can be synthesized through chemical conversion deposition technology as protective coatings for surface modification of the biodegradable magnesium alloy implants. The design idea of the new type of biomaterial is belong to the concept of "third generation biomaterial". Corrosion behavior and bioactivity of coated magnesium alloy are the key issues during implantation. In this study, preparation and corrosion behavior of magnesium phytic acid/hydroxyapatite composite coatings on magnesium alloy were studied. The basic findings and significance of this paper are as follows: 1. A novel environmentally friendly, homogenous and crack-free magnesium phytic acid/hydroxyapatite composite coating was fabricated on AZ31 magnesium alloy via chemical conversion deposition technology with the aim of enhancing its corrosion resistance and

  5. Comparison of Physical-chemical and Mechanical Properties of Chlorapatite and Hydroxyapatite Plasma Sprayed Coatings

    PubMed Central

    Demnati, Imane; Grossin, David; Marsan, Olivier; Bertrand, Ghislaine; Collonges, Gérard; Combes, Christèle; Parco, Maria; Braceras, Inigo; Alexis, Joel; Balcaen, Yannick; Rey, Christian

    2015-01-01

    Chlorapatite can be considered a potential biomaterial for orthopaedic applications. Its use as plasma-sprayed coating could be of interest considering its thermal properties and particularly its ability to melt without decomposition unlike hydroxyapatite. Chlorapatite (ClA) was synthesized by a high-temperature ion exchange reaction starting from commercial stoichiometric hydroxyapatites (HA). The ClA powder showed similar characteristics as the original industrial HA powder, and was obtained in the monoclinic form. The HA and ClA powders were plasma-sprayed using a low-energy plasma spraying system with identical processing parameters. The coatings were characterized by physical-chemical methods, i.e. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, including distribution mapping of the main phases detected such as amorphous calcium phosphate (ACP), oxyapatite (OA), and HA or ClA. The unexpected formation of oxyapatite in ClA coatings was assigned to a side reaction with contaminating oxygenated species (O2, H2O). ClA coatings exhibited characteristics different from HA, showing a lower content of oxyapatite and amorphous phase. Although their adhesion strength was found to be lower than that of HA coatings, their application could be an interesting alternative, offering, in particular, a larger range of spraying conditions without formation of massive impurities. PMID:25893015

  6. Biocompatibility of MG-63 cells on collagen, poly-L-lactic acid, hydroxyapatite scaffolds with different parameters.

    PubMed

    Cecen, Berivan; Kozaci, Didem; Yuksel, Mithat; Erdemli, Diler; Bagriyanik, Alper; Havitcioglu, Hasan

    2015-03-18

    In this study, osteoblast-like MG-63 cells were cultured on 3 different scaffold types composed of (a) collagen + poly-L-lactic acid (PLLA), (b) collagen + hydroxyapatite (HA; 30ºC) or (c) collagen + hydroxyapatite (HA; 37ºC) and produced with different porosities. Biomechanical properties of the scaffolds were characterized by tensile strength measurements. Properties of the cell-seeded scaffolds were evaluated with scanning electron microscopy (SEM). Cell adhesion and proliferation capacities were evaluated. Alkaline phosphatase (ALP) levels in media were measured. Transmission electron microscopy (TEM) and histological analyses were used to assess morphological characteristics. Our results showed that collagen-based PLLA and HA scaffolds have good cell biocompatibility. MTT test showed that the scaffolds exhibited no cytotoxicity. According to the force and displacement data, collagen + HA at 37ºC showed the highest mechanical strength and displacement. The results suggest that collagen-based PLLA and HA scaffolds might improve osteoblastic growth in vitro and have biomaterial integration potential in possible therapeutic approaches for future clinical studies.

  7. Biodegradable magnesium-hydroxyapatite metal matrix composites.

    PubMed

    Witte, Frank; Feyerabend, Frank; Maier, Petra; Fischer, Jens; Störmer, Michael; Blawert, Carsten; Dietzel, Wolfgang; Hort, Norbert

    2007-04-01

    Recent studies indicate that there is a high demand to design magnesium alloys with adjustable corrosion rates and suitable mechanical properties. An approach to this challenge might be the application of metal matrix composite (MMC) based on magnesium alloys. In this study, a MMC made of magnesium alloy AZ91D as a matrix and hydroxyapatite (HA) particles as reinforcements have been investigated in vitro for mechanical, corrosive and cytocompatible properties. The mechanical properties of the MMC-HA were adjustable by the choice of HA particle size and distribution. Corrosion tests revealed that HA particles stabilised the corrosion rate and exhibited more uniform corrosion attack in artificial sea water and cell solutions. The phase identification showed that all samples contained hcp-Mg, Mg(17)Al(12), and HA before and after immersion. After immersion in artificial sea water CaCO3 was found on MMC-HA surfaces, while no formation of CaCO3 was found after immersion in cell solutions with and without proteins. Co-cultivation of MMC-HA with human bone derived cells (HBDC), cells of an osteoblasts lineage (MG-63) and cells of a macrophage lineage (RAW264.7) revealed that RAW264.7, MG-63 and HBDC adhere, proliferate and survive on the corroding surfaces of MMC-HA. In summary, biodegradable MMC-HA are cytocompatible biomaterials with adjustable mechanical and corrosive properties.

  8. Microradiographic microsphere manipulator

    DOEpatents

    Singleton, Russell M.

    1980-01-01

    A method and apparatus for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated to relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres.

  9. Microspheres

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Vital information on a person's physical condition can be obtained by identifying and counting the population of T-cells and B-cells, lymphocytes of the same shape and size that help the immune system protect the body from the invasion of disease. The late Dr. Alan Rembaum developed a method for identifying the cells. The method involved tagging the T-cells and B-cells with microspheres of different fluorescent color. Microspheres, which have fluorescent dye embedded in them, are chemically treated so that they can link with antibodies. With the help of a complex antibody/antigen reaction, the microspheres bind themselves to specific 'targets,' in this case the T-cells or B-cells. Each group of cells can then be analyzed by a photoelectronic instrument at different wavelengths emitted by the fluorescent dyes. Same concept was applied to the separation of cancer cells from normal cells. Microspheres were also used to conduct many other research projects. Under a patent license Magsphere, Inc. is producing a wide spectrum of microspheres on a large scale and selling them worldwide for various applications.

  10. Suspension thermal spraying of hydroxyapatite: microstructure and in vitro behaviour.

    PubMed

    Bolelli, Giovanni; Bellucci, Devis; Cannillo, Valeria; Lusvarghi, Luca; Sola, Antonella; Stiegler, Nico; Müller, Philipp; Killinger, Andreas; Gadow, Rainer; Altomare, Lina; De Nardo, Luigi

    2014-01-01

    In cementless fixation of metallic prostheses, bony ingrowth onto the implant surface is often promoted by osteoconductive plasma-sprayed hydroxyapatite coatings. The present work explores the use of the innovative High Velocity Suspension Flame Spraying (HVSFS) process to coat Ti substrates with thin homogeneous hydroxyapatite coatings. The HVSFS hydroxyapatite coatings studied were dense, 27-37μm thick, with some transverse microcracks. Lamellae were sintered together and nearly unidentifiable, unlike conventional plasma-sprayed hydroxyapatite. Crystallinities of 10%-70% were obtained, depending on the deposition parameters and the use of a TiO2 bond coat. The average hardness of layers with low (<24%) and high (70%) crystallinity was ≈3.5GPa and ≈4.5GPa respectively. The distributions of hardness values, all characterised by Weibull modulus in the 5-7 range, were narrower than that of conventional plasma-sprayed hydroxyapatite, with a Weibull modulus of ≈3.3. During soaking in simulated body fluid, glassy coatings were progressively resorbed and replaced by a new, precipitated hydroxyapatite layer, whereas coatings with 70% crystallinity were stable up to 14days of immersion. The interpretation of the precipitation behaviour was also assisted by surface charge assessments, performed through Z-potential measurements. During in vitro tests, HA coatings showed no cytotoxicity towards the SAOS-2 osteoblast cell line, and surface cell proliferation was comparable with proliferation on reference polystyrene culture plates. © 2013.

  11. Microradiographic microsphere manipulator

    DOEpatents

    Singleton, R.M.

    A method and apparatus is disclosed for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres.

  12. Factors influencing phase compositions and structure of plasma sprayed hydroxyapatite coatings during heat treatment

    NASA Astrophysics Data System (ADS)

    Lu, Yu-Peng; Song, Yi-Zhong; Zhu, Rui-Fu; Li, Mu-Sen; Lei, Ting-Quan

    2003-02-01

    Heat treatment was expected to enhance the long-term reliability of hydroxyapatite (HA) coatings on metal substrates. In this study, factors influencing phase compositions and structure of plasma sprayed hydroxyapatite coatings during heat treatment were carefully analyzed. The phases were characterized by using X-ray diffraction (XRD), the OH - ion contents were determined by Fourier transform infrared (FTIR) spectroscopy. Of the involved factors, heating temperature is of more importance. The appropriate heat treatments is (600- 700 ° C)×2 h for coatings made from fine particles (10-20 μm) and 600 ° C×2 h for coatings made from coarse particles (50-80 μm). The excessive high temperatures and long holding times were unfavorable for the structural integrity of HA.

  13. First principles study of hydroxyapatite surface

    NASA Astrophysics Data System (ADS)

    Slepko, Alexander; Demkov, Alexander A.

    2013-07-01

    The biomineral hydroxyapatite (HA) [Ca10(PO4)6(OH)2] is the main mineral constituent of mammal bone. We report a theoretical investigation of the HA surface. We identify the low energy surface orientations and stoichiometry under a variety of chemical environments. The surface most stable in the physiologically relevant OH-rich environment is the OH-terminated (1000) surface. We calculate the work function of HA and relate it to the surface composition. For the lowest energy OH-terminated surface we find the work function of 5.1 eV, in close agreement with the experimentally reported range of 4.7 eV-5.1 eV [V. S. Bystrov, E. Paramonova, Y. Dekhtyar, A. Katashev, A. Karlov, N. Polyaka, A. V. Bystrova, A. Patmalnieks, and A. L. Kholkin, J. Phys.: Condens. Matter 23, 065302 (2011), 10.1088/0953-8984/23/6/065302].

  14. A bioactive triphasic ceramic-coated hydroxyapatite promotes proliferation and osteogenic differentiation of human bone marrow stromal cells.

    PubMed

    Nair, Manitha B; Bernhardt, Anne; Lode, Anja; Heinemann, Christiane; Thieme, Sebastian; Hanke, Thomas; Varma, Harikrishna; Gelinsky, Michael; John, Annie

    2009-08-01

    Hydroxyapatite (HA) ceramics are widely used as bone graft substitutes because of their biocompatibility and osteoconductivity. However, to enhance the success of therapeutic application, many efforts are undertaken to improve the bioactivity of HA. We have developed a triphasic, silica-containing ceramic-coated hydroxyapatite (HASi) and evaluated its performance as a scaffold for cell-based tissue engineering applications. Human bone marrow stromal cells (hBMSCs) were seeded on both HASi and HA scaffolds and cultured with and without osteogenic supplements for a period of 4 weeks. Cellular responses were determined in vitro in terms of cell adhesion, viability, proliferation, and osteogenic differentiation, where both materials exhibited excellent cytocompatibility. Nevertheless, an enhanced rate of cell proliferation and higher levels of both alkaline phosphatase expression and activity were observed for cells cultured on HASi with osteogenic supplements. These findings indicate that the bioactivity of HA endowed with a silica-containing coating has definitely influenced the cellular activity, projecting HASi as a suitable candidate material for bone regenerative therapy.

  15. Review of ferroelectric hydroxyapatite and its application to biomedicine

    NASA Astrophysics Data System (ADS)

    Lang, Sidney B.

    2016-08-01

    Hydroxyapatite (HA) is a major component of bone in humans and animals. Until about 10 years ago, it was considered to have a centrosymmetric crystal structure and could not contribute to the well-known piezoelectric effect in bone. This review describes the theoretical and experimental studies that showed that HA does have a non-centrosymmetric structure. Recent experiments have shown that HA exhibits piezoelectricity, pyroelectricity, and ferroelectricity. It has been made in the form of thick films and as space-charge electrets. It has an important biomedical application as an implant for bone cell attachment and growth. This paper is contributed in honor of the 80th birthday of my long-time friend and colleague, Bozena Hilczer.

  16. Nano-hydroxyapatite and its applications in preventive, restorative and regenerative dentistry: a review of literature.

    PubMed

    Pepla, Erlind; Besharat, Lait Kostantinos; Palaia, Gaspare; Tenore, Gianluca; Migliau, Guido

    2014-07-01

    This study aims to critically summarize the literature about nano-hydroxyapatite. The purpose of this work is to analyze the benefits of using nano-hydroxyapatite in dentistry, especially for its preventive, restorative and regenerative applications. We also provide an overview of new dental materials, still experimental, which contain the nano-hydroxyapatite in its nano-crystalline form. Hydroxyapatite is one of the most studied biomaterials in the medical field for its proven biocompatibility and for being the main constituent of the mineral part of bone and teeth. In terms of restorative and preventive dentistry, nano-hydroxyapatite has significant remineralizing effects on initial enamel lesions, certainly superior to conventional fluoride, and good results on the sensitivity of the teeth. The nano-HA has also been used as an additive material, in order to improve already existing and widely used dental materials, in the restorative field (experimental addition to conventional glass ionomer cements, that has led to significant improvements in their mechanical properties). Because of its unique properties, such as the ability to chemically bond to bone, to not induce toxicity or inflammation and to stimulate bone growth through a direct action on osteoblasts, nano-HA has been widely used in periodontology and in oral and maxillofacial surgery. Its use in oral implantology, however, is a widely used practice established for years, as this substance has excellent osteoinductive capacity and improves bone-to-implant integration.

  17. Biocompatibility and Biocorrosion of Hydroxyapatite-Coated Magnesium Plate: Animal Experiment.

    PubMed

    Lim, Ho-Kyung; Byun, Soo-Hwan; Woo, Jae-Man; Kim, Sae-Mi; Lee, Sung-Mi; Kim, Bong-Ju; Kim, Hyoun-Ee; Lee, Jung-Woo; Kim, Soung-Min; Lee, Jong-Ho

    2017-09-30

    Magnesium (Mg) has the advantage of being resorbed in vivo, but its resorption rate is difficult to control. With uncontrolled resorption, Magnesium as a bone fixation material has minimal clinical value. During resorption not only is the strength rapidly weakened, but rapid formation of metabolite also occurs. In order to overcome these disadvantages, hydroxyapatite (HA) surface coating of pure magnesium plate was attempted in this study. Magnesium plates were inserted above the frontal bone of Sprague-Dawley rats in both the control group (Bare-Mg group) and the experimental group (HA-Mg group). The presence of inflammation, infection, hydrogen gas formation, wound dehiscence, and/or plate exposure was observed, blood tests were performed, and the resorption rate and tensile strength of the retrieved metal plates were measured. The HA-Mg group showed no gas formation or plate exposure until week 12. However, the Bare-Mg group showed consistent gas formation and plate exposure beginning in week 2. WBC (White Blood Cell), BUN (Blood Urea Nitrogen), Creatinine, and serum magnesium concentration levels were within normal range in both groups. AST (Aspartate Aminotransferase) and ALT (Alanine Aminotransferase) values, however, were above normal range in some animals of both groups. The HA-Mg group showed statistically significant advantage in resistance to degradation compared to the Bare-Mg group in weeks 2, 4, 6, 8, and 12. Degradation of HA-Mg plates proceeded after week 12. Coating magnesium plates with hydroxyapatite may be a viable method to maintain their strength long enough to allow bony healing and to control the resorption rate during the initial period.

  18. Matched Comparison of Fusion Rates between Hydroxyapatite Demineralized Bone Matrix and Autograft in Lumbar Interbody Fusion.

    PubMed

    Kim, Dae Hwan; Lee, Nam; Shin, Dong Ah; Yi, Seong; Kim, Keung Nyun; Ha, Yoon

    2016-07-01

    To compare the fusion rate of a hydroxyapatite demineralized bone matrix (DBM) with post-laminectomy acquired autograft in lumbar interbody fusion surgery and to evaluate the correlation between fusion rate and clinical outcome. From January 2013 to April 2014, 98 patients underwent lumbar interbody fusion surgery with hydroxyapatite DBM (HA-DBM group) in our institute. Of those patients, 65 received complete CT scans for 12 months postoperatively in order to evaluate fusion status. For comparison with autograft, we selected another 65 patients who underwent lumbar interbody fusion surgery with post-laminectomy acquired autograft (Autograft group) during the same period. Both fusion material groups were matched in terms of age, sex, body mass index (BMI), and bone mineral density (BMD). To evaluate the clinical outcomes, we analyzed the results of visual analogue scale (VAS), Oswestry Disability Index (ODI), and Short Form Health Survey (SF-36). We reviewed the CT scans of 149 fusion levels in 130 patients (HA-DBM group, 75 levels/65 patients; Autograft group, 74 levels/65 patients). Age, sex, BMI, and BMD were not significantly different between the groups (p=0.528, p=0.848, p=0.527, and p=0.610, respectively). The HA-DBM group showed 39 of 75 fused levels (52%), and the Autograft group showed 46 of 74 fused levels (62.2%). This difference was not statistically significant (p=0.21). In the HA-DBM group, older age and low BMD were significantly associated with non-fusion (61.24 vs. 66.68, p=0.027; -1.63 vs. -2.29, p=0.015, respectively). VAS and ODI showed significant improvement after surgery when fusion was successfully achieved in both groups (p=0.004, p=0.002, HA-DBM group; p=0.012, p=0.03, Autograft group). The fusion rates of the hydroxyapatite DBM and Autograft groups were not significantly different. In addition, clinical outcomes were similar between the groups. However, older age and low BMD are risk factors that might induce non-union after surgery with

  19. Matched Comparison of Fusion Rates between Hydroxyapatite Demineralized Bone Matrix and Autograft in Lumbar Interbody Fusion

    PubMed Central

    Kim, Dae Hwan; Lee, Nam; Shin, Dong Ah; Yi, Seong; Kim, Keung Nyun

    2016-01-01

    Objective To compare the fusion rate of a hydroxyapatite demineralized bone matrix (DBM) with post-laminectomy acquired autograft in lumbar interbody fusion surgery and to evaluate the correlation between fusion rate and clinical outcome. Methods From January 2013 to April 2014, 98 patients underwent lumbar interbody fusion surgery with hydroxyapatite DBM (HA-DBM group) in our institute. Of those patients, 65 received complete CT scans for 12 months postoperatively in order to evaluate fusion status. For comparison with autograft, we selected another 65 patients who underwent lumbar interbody fusion surgery with post-laminectomy acquired autograft (Autograft group) during the same period. Both fusion material groups were matched in terms of age, sex, body mass index (BMI), and bone mineral density (BMD). To evaluate the clinical outcomes, we analyzed the results of visual analogue scale (VAS), Oswestry Disability Index (ODI), and Short Form Health Survey (SF-36). Results We reviewed the CT scans of 149 fusion levels in 130 patients (HA-DBM group, 75 levels/65 patients; Autograft group, 74 levels/65 patients). Age, sex, BMI, and BMD were not significantly different between the groups (p=0.528, p=0.848, p=0.527, and p=0.610, respectively). The HA-DBM group showed 39 of 75 fused levels (52%), and the Autograft group showed 46 of 74 fused levels (62.2%). This difference was not statistically significant (p=0.21). In the HA-DBM group, older age and low BMD were significantly associated with non-fusion (61.24 vs. 66.68, p=0.027; -1.63 vs. -2.29, p=0.015, respectively). VAS and ODI showed significant improvement after surgery when fusion was successfully achieved in both groups (p=0.004, p=0.002, HA-DBM group; p=0.012, p=0.03, Autograft group). Conclusion The fusion rates of the hydroxyapatite DBM and Autograft groups were not significantly different. In addition, clinical outcomes were similar between the groups. However, older age and low BMD are risk factors that might

  20. Characterization of Nano-Hydroxyapatite Synthesized from Sea Shells Through Wet Chemical Method

    NASA Astrophysics Data System (ADS)

    Santhosh, S.; Prabu, S. Balasivanandha

    2012-10-01

    Nano-hydroxyapatite (HA) was synthesized by a wet chemical reaction using powdered sea shells (CaO) as starting material which was converted to calcium hydroxide (Ca(OH)2) and subsequently reacted with phosphoric acid (H3PO4). Initially raw sea shells (CaCO3) were thermally converted to amorphous calcium oxide by heat treatment. Two sets of experiments were done; in the first experiment, HA powder was dried in an electric furnace and in the second experiment, the reactants were irradiated in a domestic microwave oven followed by microwave drying. In each set of experiments, the concentrations of the reactants were decreased gradually. HA was synthesized by slow addition of phosphoric acid (H3PO4) in to calcium hydroxide (Ca(OH)2) maintaining the pH of the solution at 10 to avoid the formation of calcium deficient apatites. In both the experiments, Ca:P ratio of 1.67 was maintained for the reagents. The synthesized samples showed X-ray diffraction (XRD) patterns corresponding to hydroxyapatite. The wet chemical process with furnace drying resulted in HA particles of size 7-34 nm, whereas microwave irradiated process yielded HA particles of size 34-102 nm as evidenced from XRD analyses. The above experimental work done by wet chemical synthesis to produce HA powder from sea shells is a simple processing method at room temperature. Microwave irradiation leads to uniform crystallite sizes as evident from this study, at differing concentrations of the reactants and is a comparatively easy method to synthesize HA. The high resolution scanning electron microscopy (HRSEM)/transmission electron microscopic (TEM) analyses revealed the characteristic rod-shaped nanoparticles of HA for the present study.

  1. The influence of micropore size on the mechanical properties of bulk hydroxyapatite and hydroxyapatite scaffolds.

    PubMed

    Cordell, Jacqueline M; Vogl, Michelle L; Wagoner Johnson, Amy J

    2009-10-01

    While recognized as a promising bone substitute material, hydroxyapatite (HA) has had limited use in clinical settings because of its inherent brittle behavior. It is well established that macropores ( approximately 100 microm) in a HA implant, or scaffold, are required for bone ingrowth, but recent research has shown that ingrowth is enhanced when scaffolds also contain microporosity. HA is sensitive to synthesis and processing parameters and therefore characterization for specific applications is necessary for transition to the clinic. To that end, the mechanical behavior of bulk microporous HA and HA scaffolds with multi-scale porosity (macropores between rods in the range of 250-350 microm and micropores within the rods with average size of either 5.96 microm or 16.2 microm) was investigated in order to determine how strength and reliability were affected by micropore size (5.96 microm versus 16.2 microm). For the bulk microporous HA, strength increased with decreasing micropore size in both bending (19 MPa to 22 MPa) and compression (71 MPa to 110 MPa). To determine strength reliability, the Weibull moduli for the bulk microporous HA were determined. The Weibull moduli for bending increased (became more reliable) with decreasing pore size (7 to 10) while the Weibull moduli for compression decreased (became less reliable) with decreasing pore size (9 to 6). Furthermore, the elastic properties of the bulk microporous HA (elastic modulus of 30 GPa) and the compressive strengths of the HA scaffolds with multi-scale porosity (8 MPa) did not vary with pore size. The mechanisms responsible for the trends observed were discussed.

  2. Hydroxyapatite/MCM-41 and SBA-15 Nano-Composites: Preparation, Characterization and Applications

    PubMed Central

    Anunziata, Oscar A.; Martínez, Maria L.; Beltramone, Andrea R.

    2009-01-01

    Composites of hydroxyapatite (HaP) and highly ordered large pore mesoporous silica molecular sieves such as, Al-SBA-15 and Al-MCM-41 (denoted as SBA-15 and MCM-41, respectively) were developed, characterized by XRD, BET, FTIR, HRTEM and NMR-MAS, and applied to fluoride retention from contaminated water. The proposed procedure by a new route to prepare the HaP/SBA-15 and HaP/MCM-41, composites generates materials with aluminum only in tetrahedral coordination, according to the 27Al NMR-MAS results. Free OH- groups of HaP nanocrystals, within the hosts, allowed high capacity fluoride retention. The activity of fluoride retention using HaP/MCM-41 or HaP/SBA-15 was 1-2 orders of magnitude greater, respectively, than with pure HaP.

  3. First principles study of biomineral hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Slepko, Alexander

    2010-03-01

    Hydroxyapatite (HA) [Ca10(PO4)6(OH)2] is one of the most abundant materials in mammal bone. It crystallizes within the spaces between the tropocollagen chains and strengthens the bone tissue. The mineral content of human bone increases with age reaching a maximum value from which it starts to decrease leading to diseases such as osteomalacia. Therefore, an emergent application of this study is bone repair and the production of synthetic bone. Despite its importance, little is known about the growth of HA crystallites in bones. Nor is it well understood how the HA attaches to protein chains and interacts with the surrounding aqueous solution. Using density functional theory (DFT) we calculate the theoretical ground state structure, electronic and vibration properties of hexagonal HA. We find several low energy structures and analyze the energy barriers for spontaneous phase transitions. We calculate the phonon density of states and study the surface energetics for different orientations. We identify the surfaces with highest reactivity using the frontier orbital approach and analyze interactions between these surfaces and water molecules/amino acids.

  4. Compressive and swelling behavior of cuttlebone derived hydroxyapatite loaded PVA hydrogel implants for articular cartilage

    NASA Astrophysics Data System (ADS)

    Kumar, B. Y. Santosh; Kumar, G. C. Mohan; Isloor, Arun M.

    2018-04-01

    Developing a novel antibacterial, nontoxic and biocompatible hydrogel with superior physio mechanical properties is still becoming a challenge. Herein, we synthesize hydroxyapatite (HA) powder from cuttlefish bone and prepare a series of stiff, tough, high strength, biocompatible hydrogel reinforced with HA by integrating glutaraldehyde into PVA/HA. Powder was characterized by SEM and XRD. Compressive strength and swelling properties are studied and compare the results with the properties of healthy natural articular cartilage.

  5. Synergistic interaction of platelet derived growth factor (PDGF) with the surface of PLLA/Col/HA and PLLA/HA scaffolds produces rapid osteogenic differentiation.

    PubMed

    Raghavendran, Hanumantha Rao Balaji; Mohan, Saktiswaren; Genasan, Krishnamurithy; Murali, Malliga Raman; Naveen, Sangeetha Vasudevaraj; Talebian, Sepehr; McKean, Robert; Kamarul, Tunku

    2016-03-01

    Scaffolds with structural features similar to the extracellular matrix stimulate rapid osteogenic differentiation in favorable microenvironment and with growth factor supplementation. In this study, the osteogenic potential of electrospun poly-l-lactide/hydroxyapatite/collagen (PLLA/Col/HA, PLLA/HA and PLLA/Col) scaffolds were tested in vitro with the supplementation of platelet derived growth factor-BB (PDGF-BB). Cell attachment and topography, mineralization, extracellular matrix protein localization, and gene expression of the human mesenchymal stromal cells were compared between the fibrous scaffolds PLLA/Col/HA, PLLA/Col, and PLLA/HA. The levels of osteocalcin, calcium, and mineralization were significantly greater in the PLLA/Col/HA and PLLA/HA compared with PLLA/Col. High expression of fibronectin, intracellular adhesion molecule, cadherin, and collagen 1 (Col1) suggests that PLLA/Col/HA and PLLA/HA scaffolds had superior osteoinductivity than PLLA/Col. Additionally, osteopontin, osteocalcin, osterix, Runt-related transcription factor 2 (Runx2), and bone morphogenic protein (BMP2) expression were higher in PLLA/Col/HA and PLLA/HA compared with PLLA/Col. In comparison with PLLA/Col, the PLLA/Col/HA and PLLA/HA scaffolds presented a significant upregulation of the genes Runx2, Col 1, Integrin, osteonectin (ON), bone gamma-carboxyglutamic acid-containing protein (BGALP), osteopontin (OPN), and BMP2. The upregulation of these genes was further increased with PDGF-BB supplementation. These results show that PDGF-BB acts synergistically with PLLA/Col/HA and PLLA/HA to enhance the osteogenic differentiation potential. Therefore, this combination can be used for the rapid expansion of bone marrow stromal cells into bone-forming cells for tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Comparison on mechanical properties of single layered and bilayered chitosan-gelatin coated porous hydroxyapatite scaffold prepared through freeze drying method

    NASA Astrophysics Data System (ADS)

    Effendi, M. D.; Gustiono, D.; Lukmana; Ayu, D.; Kurniawati, F.

    2017-02-01

    Biopolymer coated porous hydroxyapatite (HA) scaffolds were prepared for tissue engineering trough freeze drying method and impregnation. in this study, to mimic the mineral and organic component of natural bone, synthetic hydroxapatite (HA) scaffolds coated by polymer were prepared. Highly porous Hap scaffolds, fabricated by synthetic HA impregnation method on polyurethane foam, were coated with polymer coating solution, consisting of chitosan, Gelatin, and bilayered chitosan-gelatin prepared by aging and impregnating technique. For the purpose of comparison, The bare scaffolds without polymer coating layer were investigated. The Bare scaffolds were highly porous and interconnected with a pore size of around 150 µm-714 µm, has porosity at around 67,7% -85,7%, and has mechanical strength at around 0.06 Mpa - 0.071 Mpa, which is suitable for osteoblast cell Proliferation. Chitosan coated porous HA scaffold and gelatin coated porous HA scaffold had mechanical strength at around 0.81-0.85 Mpa, and 1.32-1.34 Mpa, respectively, with weight ratio of biopolymer and Hap was around 18%-22%. To compare these results, the coating on the bare scaffold with gelatin and chitosan had been conducted. Based on the result of FTIR, it could be concluded that coating procedure applied on porous hydroxy apatite (HA) coated by gelatin, chitosan coated HA scaffold, and bilayered Gelatin-chitosan coated porous HA scaffold, confirming that for allsampleshad no significant chemical effect on the coating structure. The compressive strength of bilayered Gelatin-chitosan coated HA scaffold had middle values between the rest, at around 1,06-1.2 Mpa for the samples at the same weight ratio of biopolymer: HA (around 18% - 22%). These results also confirming that coating by gelatin on porous hydroxyapatite was highest compresive strength and can be applied to improve mechanical properties of porous hydroxyapatite bare scaffold

  7. The Influence of Chitosan Concentration on Synthesis of Hydroxyapatite Scaffold on Crystallinity and Surface Morphology

    NASA Astrophysics Data System (ADS)

    Yudyanto; Hartatiek; Prasasti, R. W.; Hariyanto, Y. A.; Hidayat, N.

    2018-05-01

    Hydroxyapatite (HA) is a bioceramic material having a chemical formula (Ca10(PO4)6(OH)2) similar to the chemical structure of bone and hard tissue in humans. Recently, HA-scaffold has been intensively developed by many researchers due to its potential application in dealing with tissue injured. The implantation of HA-scaffold into bone defect aims to help and stimulate the growth of new bone tissue. Crystallinity and microstructure are properties that need to be considered to synthesis HA scaffold. Although, HA is biocompatible and osteoconductive but low biodegradable, to solve these problems added chitosan. Chitosan is a biopolymeric material with specific properties, in terms of biocompatible, non-toxic, osteoconductive, biodegradable, and not carcinogenc. In addition, a natural polymeric chitosan has similarities with the extracellular matrix, in terms of good biological performance and inherent cellular interactions. In this study, HA-scaffold was synthesized using Ca(OH)2 as the raw material of natural calcite mineral, H3PO4, and a solid polyurethane polymer (sponge) as forming of pores by sol-gel method. The addition of chitosan concentration of 0 %, 2 % and 3 % in hydroxyapatite scaffold evaluated its influences on crystallinity and surface morphology. The phase, crystallinity and crystal size are evaluated by XRD. Functional groups in HA scaffold and HA compounds were evaluated with FTIR. The results showed that HA has Ca/P ratio of 1.64. The addition of chitosan concentration caused the decrease of crystallinity and increased the pore size. Meanwhile the crystal sizes were obtained: 49.99 nm (HA), 54.37 nm (HA-scaffold without chitosan), 54.98 nm (HA-scaffold with 2% chitosan), and 40.44 nm (HA-scaffold with 3 % chitosan).

  8. The Mechanical Properties and Modeling of Creep Behavior of UHMWPE/Nano-HA Composites

    NASA Astrophysics Data System (ADS)

    Li, Fan; Gao, Lilan; Gao, Hong; Cui, Yun

    2017-09-01

    Composites with different levels of hydroxyapatite (HA) content and ultra-high molecular weight polyethylene (UHMWPE) were prepared in this work. Mechanical properties of the composites were examined here, and to evaluate the effect of HA particles on the time-dependent behavior of the pure matrix, the creep and recovery performance of composites at various stress levels were also researched. As expected, the addition of HA influenced the time-dependent response of the UHMWPE and the effect had a strong dependence on the HA content. The creep and recovery strain of the composites significantly decreased with increasing HA content, and tensile properties were also impaired, which was due to the concentration of HA fillers. The mechanism and effect of HA dispersed into the UHMWPE matrix were examined by scanning electron microscopy. Additionally, since variations in the adjusted parameters revealed the impact of HA on the creep behavior of the UHMWPE matrix, Findley's model was employed. The results indicated that the analytical model was accurate for the prediction of creep of the pure matrix and its composites.

  9. Flexible Microsphere-Embedded Film for Microsphere-Enhanced Raman Spectroscopy.

    PubMed

    Xing, Cheng; Yan, Yinzhou; Feng, Chao; Xu, Jiayu; Dong, Peng; Guan, Wei; Zeng, Yong; Zhao, Yan; Jiang, Yijian

    2017-09-27

    Dielectric microspheres with extraordinary microscale optical properties, such as photonic nanojets, optical whispering-gallery modes (WGMs), and directional antennas, have drawn interest in many research fields. Microsphere-enhanced Raman spectroscopy (MERS) is an alternative approach for enhanced Raman detection by dielectric microstructures. Unfortunately, fabrication of microsphere monolayer arrays is the major challenge of MERS for practical applications on various specimen surfaces. Here we report a microsphere-embedded film (MF) by immersing a highly refractive microsphere monolayer array in the poly(dimethylsiloxane) (PDMS) film as a flexible MERS sensing platform for one- to three-dimensional (1D to 3D) specimen surfaces. The directional antennas and wave-guided whispering-gallery modes (WG-WGMs) contribute to the majority of Raman enhancement by the MFs. Moreover, the MF can be coupled with surface-enhanced Raman spectroscopy (SERS) to provide an extra >10-fold enhancement. The limit of detection is therefore improved for sensing of crystal violet (CV) and Sudan I molecules in aqueous solutions at concentrations down to 10 -7 M. A hybrid dual-layer microsphere enhancer, constructed by depositing a MF onto a microsphere monolayer array, is also demonstrated, wherein the WG-WGMs become dominant and boost the enhancement ratio >50-fold. The present work opens up new opportunities for design of cost-effective and flexible MERS sensing platforms as individual or associated techniques toward practical applications in ultrasensitive Raman detection.

  10. Hydroxyapatite synthesis on solid surfaces using a biological approach

    NASA Astrophysics Data System (ADS)

    Wang, A.; Mei, J.; Tse, Y. Y.; Jones, I. P.; Sammons, R. L.

    2012-12-01

    Many naturally occurring mineralisation processes yield hydroxyapatite (HA) or related salts, but biological routes to calcification have not generally been exploited for production of hydroxyapatite for clinical and industrial applications. Serratia sp. NCIMB 40259 is a non-pathogenic Gram-negative bacterium which is capable of growing as a biofilm on many surfaces and can be used to form HA coatings on a variety of polymeric and metallic materials, including titanium. Here we review previous work and report the results of more recent studies on the influence of titanium compositional and surface properties on Serratia adherence and proliferation and biomineralisation on commercially pure titanium (cp Ti) discs and a Ti mesh. Bacterial adherence was equivalent on cpTi and Ti6Al4V, and biofilms formed on both rough and mirror-polished cpTi surfaces. Embedded alumina particles and alkali treatment did not noticeably alter the precipitation of Serratia HA, nor the structure of the coating in comparison with non-treated substrates. Coatings were retained after sintering at 800°C in argon, although the original curved plate-like crystals changed to nano-scale β-tricalcium phosphate particles. A phosphorous-rich diffusion zone formed at the coating-titanium interface. Bacterial mineralisation may have applications as a method for producing coatings on implants in non load-bearing sites, and non-clinical applications where a high surface area is the major concern.

  11. Hydroxyapatite electrodeposition on anodized titanium nanotubes for orthopedic applications

    NASA Astrophysics Data System (ADS)

    Parcharoen, Yardnapar; Kajitvichyanukul, Puangrat; Sirivisoot, Sirinrath; Termsuksawad, Preecha

    2014-08-01

    Nanotubes modification for orthopedic implants has shown interesting biological performances (such as improving cell adhesion, cell differentiation, and enhancing osseointegration). The purpose of this study is to investigate effect of titanium dioxide (TiO2) nanotube feature on performance of hydroxyapatite-coated titanium (Ti) bone implants. TiO2 nanotubes were prepared by anodization using ammonium fluoride electrolyte (NH4F) with and without modifiers (PEG400 and Glycerol) at various potential forms, and times. After anodization, the nanotubes were subsequently annealed. TiO2 nanotubes were characterized by scanning electron microscope and X-ray diffractometer. The amorphous to anatase transformation due to annealing was observed. Smooth and highly organized TiO2 nanotubes were found when high viscous electrolyte, NH4F in glycerol, was used. Negative voltage (-4 V) during anodization was confirmed to increase nanotube thickness. Length of the TiO2 nanotubes was significantly increased by times. The TiO2 nanotube was electrodeposited with hydroxyapatite (HA) and its adhesion was estimated by adhesive tape test. The result showed that nanotubes with the tube length of 560 nm showed excellent adhesion. The coated HA were tested for biological test by live/dead cell straining. HA coated on TiO2 nanotubes showed higher cells density, higher live cells, and more spreading of MC3T3-E1 cells than that growing on titanium plate surface.

  12. Characterization of mechanical properties of hydroxyapatite-silicon-multi walled carbon nano tubes composite coatings synthesized by EPD on NiTi alloys for biomedical application.

    PubMed

    Khalili, Vida; Khalil-Allafi, Jafar; Sengstock, Christina; Motemani, Yahya; Paulsen, Alexander; Frenzel, Jan; Eggeler, Gunther; Köller, Manfred

    2016-06-01

    Release of Ni(1+) ions from NiTi alloy into tissue environment, biological response on the surface of NiTi and the allergic reaction of atopic people towards Ni are challengeable issues for biomedical application. In this study, composite coatings of hydroxyapatite-silicon multi walled carbon nano-tubes with 20wt% Silicon and 1wt% multi walled carbon nano-tubes of HA were deposited on a NiTi substrate using electrophoretic methods. The SEM images of coated samples exhibit a continuous and compact morphology for hydroxyapatite-silicon and hydroxyapatite-silicon-multi walled carbon nano-tubes coatings. Nano-indentation analysis on different locations of coatings represents the highest elastic modulus (45.8GPa) for HA-Si-MWCNTs which is between the elastic modulus of NiTi substrate (66.5GPa) and bone tissue (≈30GPa). This results in decrease of stress gradient on coating-substrate-bone interfaces during performance. The results of nano-scratch analysis show the highest critical distance of delamination (2.5mm) and normal load before failure (837mN) as well as highest critical contact pressure for hydroxyapatite-silicon-multi walled carbon nano-tubes coating. The cell culture results show that human mesenchymal stem cells are able to adhere and proliferate on the pure hydroxyapatite and composite coatings. The presence of both silicon and multi walled carbon nano-tubes (CS3) in the hydroxyapatite coating induce more adherence of viable human mesenchymal stem cells in contrast to the HA coated samples with only silicon (CS2). These results make hydroxyapatite-silicon-multi walled carbon nano-tubes a promising composite coating for future bone implant application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Synthesis and characterization of new composite materials based on poly(methacrylic acid) and hydroxyapatite with applications in dentistry.

    PubMed

    Cucuruz, Andrei Tiberiu; Andronescu, Ecaterina; Ficai, Anton; Ilie, Andreia; Iordache, Florin

    2016-08-30

    The use of methacrylic acid (MAA) in medicine was poorly investigated in the past but can be of great importance because the incorporation of hydroxyapatite (HA) can lead to new composite materials with good properties due to the strong electrostatic interactions between carboxylate groups of polymer and Ca(2+) ions from HA. The scope of this study was to determine the potential of using composite materials based on poly(methacrylic acid) (PMAA) and hydroxyapatite in dentistry. Two routes of synthesis were taken into account: i) HA was synthesised in situ and ii) commercial HA was used. Fourier transform infrared spectroscopy and X-ray diffraction were used for compositional assessments. Scanning electron microscopy was performed to determine the morphology and differential thermal analysis (DTA) coupled with thermogravimetric analysis (TG) was used to study the thermal behaviour and to observe quantitative changes. In-vitro tests were also performed in order to evaluate the biocompatibility of both PMAA/HA composites by monitoring the development potential of human endothelial cells using MTT assay and fluorescent microscopy. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Fabrication and characterization of plasma-sprayed HA/SiO(2) coatings for biomedical application.

    PubMed

    Morks, M F

    2008-01-01

    Fused silica powder has been mixed with hydroxyapatite (HA) powder and plasma sprayed by using gas tunnel-type plasma jet. The influence of silica content (10 wt% and 20 wt%) on the microstructure and mechanical properties of HA-silica coatings was investigated. For investigating the microstructure and mechanical properties of HA-silica coatings, SUS 304 stainless steel was used as substrate material. The spraying was carried out on roughened substrate in an atmospheric chamber. Scanning electron microscope micrographs of cross-sectioned HA/SiO(2) coatings showed that the sprayed HA coatings with 10 and 20 wt% SiO(2) have dense structure with low porosity compared to the pure HA coatings. On the other hand, as the amount of silica was increased the coatings became denser, harder and exhibited high abrasive wear resistance. The presence of silica significantly improved the adhesive strength of HA/SiO(2) coatings mainly due to the increase in bonding strength of the coating at the interface.

  15. Chondroitin sulfate template-mediated biomimetic synthesis of nano-flake hydroxyapatite

    NASA Astrophysics Data System (ADS)

    He, Dan; Xiao, Xiufeng; Liu, Fang; Liu, Rongfang

    2008-11-01

    By Ca(NO 3) 2·4H 2O and (NH 4) 3PO 4·3H 2O as reagents and chondroitin sulfate (ChS) as a template, nano-flake hydroxyapatite (HA) is synthesized using a biomimetic method according to the biomineralization theory. HA crystals obtained are characterized in crystalline phase, microstructure, chemical composition and morphology by X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), transmission electron microscopy (TEM) and elemental analysis respectively. UV-vis spectrum is adopted to investigate interactions between functional groups ChS and HA. The results show that HA crystal nucleation and growth take place in chemical interactions between HA crystals and ChS as a template. And elemental analysis indicates that obtained HA contains a small amount of ChS. Furthermore, ChS concentration significantly affects the morphology of HA crystals. Staple-fiber-like HA crystals can be obtained at a low concentration in ChS, and flake-like HA crystals synthesized at a high concentration (≥0.5 wt.%) of ChS as a template.

  16. Hydroxyapatite/poly(epsilon-caprolactone) composite coatings on hydroxyapatite porous bone scaffold for drug delivery.

    PubMed

    Kim, Hae-Won; Knowles, Jonathan C; Kim, Hyoun-Ee

    2004-01-01

    Hydroxyapatite (HA) porous scaffold was coated with HA and polycaprolactone (PCL) composites, and antibiotic drug tetracycline hydrochloride was entrapped within the coating layer. The HA scaffold obtained by a polymeric reticulate method, possessed high porosity ( approximately 87%) and controlled pore size (150-200 microm). Such a well-developed porous structure facilitated usage in a drug delivery system due to its high surface area and blood circulation efficiency. The PCL polymer, as a coating component, was used to improve the brittleness and low strength of the HA scaffold, as well to effectively entrap the drug. To improve the osteoconductivity and bioactivity of the coating layer, HA powder was hybridized with PCL solution to make the HA-PCL composite coating. With alteration in the coating concentration and HA/PCL ratio, the morphology, mechanical properties, and biodegradation behavior were investigated. Increasing the concentration rendered the stems thicker and some pores to be clogged; as well increasing the HA/PCL ratio made the coating surface be rough due to the large amount of HA particles. However, for all concentrations and compositions, uniform coatings were formed, i.e., with the HA particles being dispersed homogeneously in the PCL sheet. With the composite coating, the mechanical properties, such as compressive strength and elastic modulus were improved by several orders of magnitude. These improvements were more significant with thicker coatings, while little difference was observed with the HA/PCL ratio. The in vitro biodegradation of the composite coatings in the phosphate buffered saline solution increased linearly with incubation time and the rate differed with the coating concentration and the HA/PCL ratio; the higher concentration and HA amount caused the increased biodegradation. At short period (<2 h), about 20-30% drug was released especially due to free drug at the coating surface. However, the release rate was sustained for

  17. Synthesis, bioactivity and zeta potential investigations of chlorine and fluorine substituted hydroxyapatite.

    PubMed

    Fahami, Abbas; Beall, Gary W; Betancourt, Tania

    2016-02-01

    Chlorine and fluorine substituted hydroxyapatites (HA-Cl-F) with different degrees of ion replacement were successfully prepared by the one step mechanochemical activation method. X-ray diffraction (XRD) and FT-IR spectra indicated that substitution of these anions in milled powders resulted in the formation of pure hydroxyapatite phase except for the small observed change in the lattice parameters and unit cell volumes of the resultant hydroxyapatite. Microscopic observations showed that the milled product had a cluster-like structure made up of polygonal and spherical particles with an average particle size of approximately ranged from 20±5 to 70±5nm. The zeta potential of milled samples was performed at three different pH (5, 7.4, and 9). The obtained zeta potential values were negative for all three pH values. Negative zeta potential was described to favor osseointegration, apatite nucleation, and bone regeneration. The bioactivity of samples was investigated on sintered pellets soaked in simulated body fluid (SBF) solution and apatite crystals formed on the surface of the pellets after being incubated for 14days. Zeta potential analysis and bioactivity experiment suggested that HA-Cl-F will lead to the formation of new apatite particles and therefore be a potential implant material. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. The Effect of Zirconia in Hydroxyapatite on Staphylococcus epidermidis Growth.

    PubMed

    Siswomihardjo, Widowati; Sunarintyas, Siti; Tontowi, Alva Edy

    2012-01-01

    Synthetic hydroxyapatite (HA) has been widely used and developed as the material for bone substitute in medical applications. The addition of zirconia is needed to improve the strength of hydroxyapatite as the bone substitute. One of the drawbacks in the use of biomedical materials is the occurrence of biomaterial-centred infections. The recent method of limiting the presence of microorganism on biomaterials is by providing biomaterial-bound metal-containing compositions. In this case, S. epidermidis is the most common infectious organism in biomedical-centred infection. Objective. This study was designed to evaluate the effect of zirconia concentrations in hydroxyapatite on the growth of S. epidermidis. Methods and Materials. The subjects of this study were twenty hydroxyapatite discs, divided into four groups in which one was the control and the other three were the treatment groups. Zirconia powder with the concentrations of 20%, 30%, and 40% was added into the three different treatment groups. Scanning electron microscope analysis was performed according to the hydroxyapatite and hydroxyapatite-zirconia specimens. All discs were immersed into S. epidermidis culture for 24 hours and later on they were soaked into a medium of PBS. The cultured medium was spread on mannitol salt agar. After incubation for 24 hours at 37°C , the number of colonies was measured with colony counter. Data obtained were analyzed using the ANOVA followed by the pairwise comparison. Result. The statistical analysis showed that different concentrations of zirconia powder significantly influenced the number of S. epidermidis colony (P < 0.05) . Conclusion. The addition of zirconia into hydroxyapatite affected the growth of S. epidermidis. Hydroxyapatite with 20% zirconia proved to be an effective concentration to inhibit the growth of S. epidermidis colony.

  19. The Effect of Zirconia in Hydroxyapatite on Staphylococcus epidermidis Growth

    PubMed Central

    Siswomihardjo, Widowati; Sunarintyas, Siti; Tontowi, Alva Edy

    2012-01-01

    Synthetic hydroxyapatite (HA) has been widely used and developed as the material for bone substitute in medical applications. The addition of zirconia is needed to improve the strength of hydroxyapatite as the bone substitute. One of the drawbacks in the use of biomedical materials is the occurrence of biomaterial-centred infections. The recent method of limiting the presence of microorganism on biomaterials is by providing biomaterial-bound metal-containing compositions. In this case, S. epidermidis is the most common infectious organism in biomedical-centred infection. Objective. This study was designed to evaluate the effect of zirconia concentrations in hydroxyapatite on the growth of S. epidermidis. Methods and Materials. The subjects of this study were twenty hydroxyapatite discs, divided into four groups in which one was the control and the other three were the treatment groups. Zirconia powder with the concentrations of 20%, 30%, and 40% was added into the three different treatment groups. Scanning electron microscope analysis was performed according to the hydroxyapatite and hydroxyapatite-zirconia specimens. All discs were immersed into S. epidermidis culture for 24 hours and later on they were soaked into a medium of PBS. The cultured medium was spread on mannitol salt agar. After incubation for 24 hours at 37°C , the number of colonies was measured with colony counter. Data obtained were analyzed using the ANOVA followed by the pairwise comparison. Result. The statistical analysis showed that different concentrations of zirconia powder significantly influenced the number of S. epidermidis colony (P < 0.05) . Conclusion. The addition of zirconia into hydroxyapatite affected the growth of S. epidermidis. Hydroxyapatite with 20% zirconia proved to be an effective concentration to inhibit the growth of S. epidermidis colony. PMID:22919390

  20. Anisotropic growth of hydroxyapatite on the silk fibroin films

    NASA Astrophysics Data System (ADS)

    Li, Yucheng; Cai, Yurong; Kong, Xiangdong; Yao, Juming

    2008-12-01

    Bombyx mori silk fibroin is of practical interest for its excellent intrinsic properties utilizable in the biotechnological and biomedical fields. Here, the silk fibroin films were pretreated with different methods and then used as the template for the hydroxyapatite (HA) crystal growth. To study the effect of silk films' surface structure on the protein biomineralization, the films were immersed into 1.5 times simulated body fluid (1.5 × SBF) to induce the HA deposition at 37 °C. The results showed that an anisotropic growth of HA crystals was observed on the different films as judging from XRD, TEM and HRTEM data. This was thought that the positions and density of carboxyl groups, C dbnd O and amino groups on the surface of SF films may be different, which play the key effect on HA crystal growth.

  1. Pyroelectric, piezoelectric, and photoeffects in hydroxyapatite thin films on silicon

    NASA Astrophysics Data System (ADS)

    Lang, S. B.; Tofail, S. A. M.; Gandhi, A. A.; Gregor, M.; Wolf-Brandstetter, C.; Kost, J.; Bauer, S.; Krause, M.

    2011-03-01

    Hydroxyapatite (HA) is the major component of bone and is used in artificial form in many biomedical applications. It was once believed to have a centrosymmetric crystal structure. In theoretical and experimental studies published in 2005, it was shown to have a monoclinic P21 structure. In the work reported here, 500 nm films of HA were spin-coated on silicon wafers. The materials were not poled. They had a nonuniform polarization distribution and exhibited pyroelectricity, piezoelectricity, and photoeffects. Structures of this type may have a number of technological applications.

  2. Formation and bioactivity of HA nanorods on micro-arc oxidized zirconium.

    PubMed

    Zhang, Lan; Zhu, Shaoyu; Han, Yong; Xiao, Chengzhang; Tang, Wu

    2014-10-01

    A microporous and CaO partially stabilized zirconia (Ca-PSZ) coating covered with hydroxyapatite (HA) nanorods is fabricated on Zr substrate by a hybrid approach of micro-arc oxidation (MAO) and hydrothermal treatment (HT). The effect of P ions in HT solution on the density and morphology of HA was investigated; the hydrophilicity and apatite-forming ability of the Ca-PSZ coating with HA nanorods were also examined. High-density HA nanorods (with a mean diameter of 50 nm and length of 450 nm) grow on the Ca-PSZ coating after HT in a solution containing 0.002 M β-glycerophosphate disodium (β-GP). However, only a few of coarse-grained HA crystallites grow in the MAOed pores after HT in distilled water or in an ammonia aqueous solution with an initial pH value equal to the solution containing 0.002 M β-GP. P ions in the HT solution are thought to significantly promote the formation of HA nanorods. The Ca-PSZ coating covered with HA nanorods displays good hydrophilicity and excellent apatite-inducing ability, and the induced apatite prefers to nucleate on the basal-faceted surfaces of HA nanorods. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Does hydroxyapatite coating enhance ingrowth and improve longevity of a Zweymuller type stem? A double-blinded randomised RSA trial.

    PubMed

    Hoornenborg, Daniel; Sierevelt, Inger N; Spuijbroek, Joost A; Cheung, John; van der Vis, Harm M; Beimers, Lijkele; Haverkamp, Daniel

    2017-09-11

    An ongoing discussion is whether using a hydroxyapatite coating enhances the ingrowth and longevity of a femoral stem in total hip arthroplasty. The best way to predict speed of ingrowth and long-term outcome is by evaluating micromotion by radiostereometric analysis. To study the effect of hydroxyapatite (HA) coating on the migration of the SL-PLUS hip stem, we performed a prospective double blind randomised controlled trial comparing the early migration of the hydroxyapatite (HA)-coated SL-PLUS stem compared to the Standard (non-coated) SL-PLUS stem. 51 patients were randomly assigned to receive either an uncoated or a HA-coated femoral component during total hip replacement. RSA images were obtained direct postoperatively and at 6 weeks, 12 weeks, 6 months, 12 months and 24 months. HOOS scores were obtained preoperative and at final follow-up. RSA evaluation demonstrated significant migration up to 3 months postoperatively in both groups. After initial setting no significant migration was observed. There was no significant difference in migration between the HA-coated group and the uncoated group.Both Harris Hip Score (HHS) and HOOS domain scores (pain and ADL) significantly improved compared to baseline at 24 months after surgery in both treatment groups (p<0.001 for all comparisons). Improvement did not differ significantly between the 2 groups. At 2 years follow-up, the HA-coated and uncoated Zweymuller type, distal fitting stem do not show different migration patterns.

  4. Osteoinductive-nanoscaled silk/HA composite scaffolds for bone tissue engineering application.

    PubMed

    Huang, Xiaowei; Bai, Shumeng; Lu, Qiang; Liu, Xi; Liu, Shanshan; Zhu, Hesun

    2015-10-01

    Osteoinductive silk/hydroxyapatite (HA) composite scaffolds for bone regeneration were prepared by combining silk with HA/silk core-shell nanoparticles. The HA/silk nanoparticles were directly dispersed in silk solution to form uniform silk/HA blend and then composite scaffolds after a freeze-drying process. The HA/silk nanoparticles uniformly distributed in silk scaffolds at nanometer scale at varying HA content up to 40%, and substantially improved the compressive strength of the scaffolds produced. Rat bone mesenchymal stem cells (rBMSCs) were cultured in these scaffolds and cell proliferation was analyzed by confocal microscopy and DNA assay. Gene expression and biochemical assays were employed to study the influence of increasing HA/silk nanoparticles on in vitro osteogenic differentiation of rBMSCs. Increasing HA/silk nanoparticles inside silk scaffolds improved the growth and osteogenic capability of rBMSCs in the absence of osteogenic growth factors, and also significantly increased the calcium and collagen I deposition. In addition, compared to silk/HA composite scaffolds containing HA aggregates, the scaffolds loaded with HA/silk nanoparticles showed remarkably higher stiffness and better osteogenic property at same HA content, implying a preferable microenvironment for rBMSCs. These results suggest that the osteogenic property as well as mechanical property of silk/HA scaffolds could be further improved through fabricating their structure and topography at nanometer scale, providing more suitable systems for bone regeneration. © 2014 Wiley Periodicals, Inc.

  5. The Production of Porous Hydroxyapatite Scaffolds with Graded Porosity by Sequential Freeze-Casting.

    PubMed

    Lee, Hyun; Jang, Tae-Sik; Song, Juha; Kim, Hyoun-Ee; Jung, Hyun-Do

    2017-03-31

    Porous hydroxyapatite (HA) scaffolds with porosity-graded structures were fabricated by sequential freeze-casting. The pore structures, compressive strengths, and biocompatibilities of the fabricated porous HA scaffolds were evaluated. The porosities of the inner and outer layers of the graded HA scaffolds were controlled by adjusting the initial HA contents of the casting slurries. The interface between the dense and porous parts was compact and tightly adherent. The porosity and compressive strengths of the scaffold were controlled by the relative thicknesses of the dense/porous parts. In addition, the porous HA scaffolds showed good biocompatibility in terms of preosteoblast cell attachment and proliferation. The results suggest that porous HA scaffolds with load-bearing parts have potential as bone grafts in hard-tissue engineering.

  6. The Production of Porous Hydroxyapatite Scaffolds with Graded Porosity by Sequential Freeze-Casting

    PubMed Central

    Lee, Hyun; Jang, Tae-Sik; Song, Juha; Kim, Hyoun-Ee; Jung, Hyun-Do

    2017-01-01

    Porous hydroxyapatite (HA) scaffolds with porosity-graded structures were fabricated by sequential freeze-casting. The pore structures, compressive strengths, and biocompatibilities of the fabricated porous HA scaffolds were evaluated. The porosities of the inner and outer layers of the graded HA scaffolds were controlled by adjusting the initial HA contents of the casting slurries. The interface between the dense and porous parts was compact and tightly adherent. The porosity and compressive strengths of the scaffold were controlled by the relative thicknesses of the dense/porous parts. In addition, the porous HA scaffolds showed good biocompatibility in terms of preosteoblast cell attachment and proliferation. The results suggest that porous HA scaffolds with load-bearing parts have potential as bone grafts in hard-tissue engineering. PMID:28772735

  7. Sonochemical synthesis of fructose 1,6-bisphosphate dicalcium porous microspheres and their application in promotion of osteogenic differentiation.

    PubMed

    Qi, Chao; Zhou, Ding; Zhu, Ying-Jie; Sun, Tuan-Wei; Chen, Feng; Zhang, Chang-Qing

    2017-08-01

    Human bone mesenchymal stem cells (hBMSCs) have the ability to differentiate into bone and cartilage for clinical bone regeneration. Biomaterials with an innate ability to stimulate osteogenic differentiation of hBMSCs into bone and cartilage are considered attractive candidates for the applications in bone tissue engineering and regeneration. In this paper, we synthesized fructose 1,6-bisphosphate dicalcium (Ca 2 FBP) porous microspheres by the sonochemical method, and investigated the ability of Ca 2 FBP for the promotion of the osteogenic differentiation of hBMSCs. After the hBMSCs were co-cultured with the sterilized powder of Ca 2 FBP porous microspheres for different times, the cell proliferation assay, alkaline phosphatase activity assay, quantitative real-time polymerase chain reaction and western blotting were performed to investigate the bioactivity and osteogenic differentiation performance of the as-prepared product. Compared with hydroxyapatite nanorods, Ca 2 FBP porous microspheres show a superior bioactivity and osteoinductive potential, and can promote the cell differentiation of hBMSCs in vitro, thus, they are promising for applications in the tissue engineering field such as dental and bone defect repair. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Effect of aging temperature on formation of sol-gel derived fluor-hydroxyapatite nanoparticles.

    PubMed

    Joughehdoust, S; Behnamghader, A; Jahandideh, R; Manafi, S

    2010-04-01

    Synthetic hydroxyapatite (HA) has been recognized as one of the most important bone substitute materials in orthopaedics and dentistry over past few decades because of its chemical and biological similarity to the mineral phase of human bone. One solution for reduction the solubility of HA in biological environments is replacing F- by OH in HA structure and forming fluor-hydroxyapatite (FHA) solid solution. In this paper, FHA nanoparticles were successfully synthesized by a sol-gel method. Also, the influence of aging temperature on formation of FHA powder was studied. Equimolar solutions of calcium nitrate tetrahydrate, triethyl phosphite and ammonium fluoride in ethanol were used as Ca, P and F precursors. After aging at different temperatures, the synthesized powders were heat treated at 550 degrees C. The powders were investigated with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), selected area electron diffraction pattern (SAED), energy dispersive analysis of X-ray (EDAX) and zetasizer measurement. The results of XRD proved the presence of fluorapatite (FA) and HA in all samples. In addition, the formation of FHA was confirmed by FT-IR results. XRD studies also showed that the crystallites were in nanometric scale. At the same time, this result was in good agreement with the result of zetasizer analysis.

  9. Peptide Probe for Crystalline Hydroxyapatite: In Situ Detection of Biomineralization

    NASA Astrophysics Data System (ADS)

    Cicerone, Marcus; Becker, Matthew; Simon, Carl; Chatterjee, Kaushik

    2009-03-01

    While cells template mineralization in vitro and in vivo, specific detection strategies that impart chemical and structural information on this process have proven elusive. Recently we have developed an in situ based peptide probe via phage display methods that is specific to crystalline hydroxyapatite (HA). We are using this in fluorescence based assays to characterize mineralization. One application being explored is the screening of tissue engineering scaffolds for their ability to support osteogenesis. Specifically, osteoblasts are being cultured in hydrogel scaffolds possessing property gradients to provide a test bed for the HA peptide probe. Hydrogel properties that support osteogenesis and HA deposition will be identified using the probe to demonstrate its utility in optimizing design of tissue scaffolds.

  10. Poly(vinyl alcohol) hydrogel coatings with tunable surface exposure of hydroxyapatite

    PubMed Central

    Moreau, David; Villain, Arthur; Ku, David N; Corté, Laurent

    2014-01-01

    Insufficient bone anchoring is a major limitation of artificial substitutes for connective osteoarticular tissues. The use of coatings containing osseoconductive ceramic particles is one of the actively explored strategies to improve osseointegration and strengthen the bone-implant interface for general tissue engineering. Our hypothesis is that hydroxyapatite (HA) particles can be coated robustly on specific assemblies of PVA hydrogel fibers for the potential anchoring of ligament replacements. A simple dip-coating method is described to produce composite coatings made of microscopic hydroxyapatite (HA) particles dispersed in a poly(vinyl alcohol) (PVA) matrix. The materials are compatible with the requirements for implant Good Manufacturing Practices. They are applied to coat bundles of PVA hydrogel fibers used for the development of ligament implants. By means of optical and electronic microscopy, we show that the coating thickness and surface state can be adjusted by varying the composition of the dipping solution. Quantitative analysis based on backscattered electron microscopy show that the exposure of HA at the coating surface can be tuned from 0 to over 55% by decreasing the weight ratio of PVA over HA from 0.4 to 0.1. Abrasion experiments simulating bone-implant contact illustrate how the coating cohesion and wear resistance increase by increasing the content of PVA relative to HA. Using pullout experiments, we find that these coatings adhere well to the fiber bundles and detach by propagation of a crack inside the coating. These results provide a guide to select coated implants for anchoring artificial ligaments. PMID:25482413

  11. The effects of ageing time on the microstructure and properties of mesoporous silica-hydroxyapatite nanocomposite

    NASA Astrophysics Data System (ADS)

    Yousefpour, Mardali; Taherian, Zahra

    2013-02-01

    In this study, a mesoporous silica-hydroxyapatite nanocomposite (MCM-41/HA) was synthesized via sol-gel technique as a drug delivery system. The synthesis of MCM-41/hydroxyapatite nanocomposite was carried out at room temperature. The effect of various ageing time on the nanocomposite properties was studied during synthesis process. 0, 24, 36, and 48 h aging times were chosen. Textural properties and microstructure of the nanocomposites were characterized by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS), Electron Diffraction pattern (ED), and N2 adsorption-desorption. Results showed that ageing process led to HA crystals nucleation and growth on the surface of mesoporous silica. At 48 h of aging time, the surface area and total pore volume increased from 36.2 to 334 m2/g and 0.14-0.7 cm3/g, respectively. In contrast, the average pore diameter considerably decreased from 20.1 nm for (MCM-41/HA)24 to 8.39 nm for (MCM-41/HA)48. Furthermore, it was observed more homogeneous pore distribution with increasing the ageing time. In conclusion, the ageing time play an important role on textural properties of MCM-41/HA nanocomposite which could have a major effect on drug delivery properties such as molecular loading and release kinetics.

  12. Biocompatibility and Biocorrosion of Hydroxyapatite-Coated Magnesium Plate: Animal Experiment

    PubMed Central

    Woo, Jae-Man; Kim, Sae-Mi; Lee, Sung-Mi; Kim, Hyoun-Ee; Lee, Jung-Woo; Lee, Jong-Ho

    2017-01-01

    Magnesium (Mg) has the advantage of being resorbed in vivo, but its resorption rate is difficult to control. With uncontrolled resorption, Magnesium as a bone fixation material has minimal clinical value. During resorption not only is the strength rapidly weakened, but rapid formation of metabolite also occurs. In order to overcome these disadvantages, hydroxyapatite (HA) surface coating of pure magnesium plate was attempted in this study. Magnesium plates were inserted above the frontal bone of Sprague-Dawley rats in both the control group (Bare-Mg group) and the experimental group (HA-Mg group). The presence of inflammation, infection, hydrogen gas formation, wound dehiscence, and/or plate exposure was observed, blood tests were performed, and the resorption rate and tensile strength of the retrieved metal plates were measured. The HA-Mg group showed no gas formation or plate exposure until week 12. However, the Bare-Mg group showed consistent gas formation and plate exposure beginning in week 2. WBC (White Blood Cell), BUN (Blood Urea Nitrogen), Creatinine, and serum magnesium concentration levels were within normal range in both groups. AST (Aspartate Aminotransferase) and ALT (Alanine Aminotransferase) values, however, were above normal range in some animals of both groups. The HA-Mg group showed statistically significant advantage in resistance to degradation compared to the Bare-Mg group in weeks 2, 4, 6, 8, and 12. Degradation of HA-Mg plates proceeded after week 12. Coating magnesium plates with hydroxyapatite may be a viable method to maintain their strength long enough to allow bony healing and to control the resorption rate during the initial period. PMID:28973984

  13. Osteoblast and osteoclast responses to A/B type carbonate-substituted hydroxyapatite ceramics for bone regeneration.

    PubMed

    Germaini, Marie-Michèle; Detsch, Rainer; Grünewald, Alina; Magnaudeix, Amandine; Lalloue, Fabrice; Boccaccini, Aldo R; Champion, Eric

    2017-06-06

    The influence of carbonate substitution (4.4 wt%, mixed A/B type) in hydroxyapatite ceramics for bone remodeling scaffolds was investigated by separately analyzing the response of pre-osteoblasts and osteoclast-like cells. Carbonated hydroxyapatite (CHA) (Ca 9.5 (PO 4 ) 5.5 (CO 3 ) 0.5 (OH)(CO 3 ) 0.25 -CHA), mimicking the chemical composition of natural bone mineral, and pure hydroxyapatite (HA) (Ca 10 (PO 4 ) 6 (OH) 2 -HA) porous ceramics were processed to obtain a similar microstructure and surface physico-chemical properties (grain size, porosity ratio and pore size, surface roughness and zeta potential). The biological behavior was studied using MC3T3-E1 pre-osteoblastic and RAW 264.7 monocyte/macrophage cell lines. Chemical dissolution in the culture media and resorption lacunae produced by osteoclasts occur with both HA and CHA ceramics, but CHA exhibits much higher dissolution and greater bioresorption ability. CHA ceramics promoted a significantly higher level of pre-osteoblast proliferation. Osteoblastic differentiation, assessed by qRT-PCR of RUNX2 and COLIA2, and pre-osteoclastic proliferation and differentiation were not significantly different on CHA or HA ceramics but cell viability and metabolism were significantly greater on CHA ceramics. Thus, the activity of both osteoclast-like and osteoblastic cells was influenced by the carbonate substitution in the apatite structure. Furthermore, CHA showed a particularly interesting balance between biodegradation, by osteoclasts and chemical dissolution, and osteogenesis through osteoblasts' activity, to stimulate bone regeneration. It is hypothesized that this amount of 4.4 wt% carbonate substitution leads to an adapted concentration of calcium in the fluid surrounding the ceramic to stimulate the activity of cells. These results highlight the superior biological behavior of microporous 4.4 wt% A/B CHA ceramics that could beneficially replace the commonly used HA of biphasic calcium phosphates for future

  14. Influence of a TiN interlayer on the microstructure and mechanical properties of hydroxyapatite films grown by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Nelea, Valentin D.; Ristoscu, Carmen; Colis, Silviu; Arens, Simona; Pelletier, Herve; Mihailescu, Ion N.; Mille, Pierre

    2001-04-01

    Crystalline hydroxyapatite (HA) thin films grown on metallic substrates is the best choice for bone restoration. This is due to the good biological compatibility of the hydroxyapatite material combined with the good mechanical characteristics of the substrates. We deposit HA thin films by Pulsed Laser Deposition (PLD) in vacuum at room temperature using a KrF* excimer laser ((lambda) equals 248 nm, (tau) FWHM >= 20 ns). The depositions were performed directly on Ti-5Al-2.5Fe or on substrates previously coated with a TiN buffer layer. The HA deposited structures were characterized by complementary techniques: GIXRD, SEM, TEM, SAED, EDS and nanoindentation. Properties of the HA films grown with and without the TiN buffer were discussed in term of microstructure and mechanical behavior. The films with interlayer preserve the stoichiometry, are completely recrystallized and present better mechanical characteristics as compared with those without buffer.

  15. Biocompatibility of nano-hydroxyapatite/polyetheretherketone composite materials with osteoblasts cultured in vitro

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Huang, Feijuan; Wu, Zhengzhi; Ma, Rui

    2017-04-01

    The biocompatibility of the Sprague Dawley (SD) rat osteoblasts, which were cultured on the surfaces of nano-hydroxyapatite/polyetheretherketone (n-HA/PEEK) composites were investigated in this work. The osteoblasts of 24- hour old SD rats were cultured and identified by modified enzymatic digestion in vitro. The morphology and proliferation of cells were observed in CCK-8 regent staining, inverted microscopes, and by scanning electron microscopy (SEM) respectively. The results show that n-HA/PEEK composites have good biocompatibility with SD osteoblasts and that they can promote the growth of the cells that were cultured on the surfaces of the composites. The content of HA in n- HA/PEEK composites plays an important role in cell proliferation.

  16. Hierarchically nanostructured hydroxyapatite: hydrothermal synthesis, morphology control, growth mechanism, and biological activity

    PubMed Central

    Ma, Ming-Guo

    2012-01-01

    Hierarchically nanosized hydroxyapatite (HA) with flower-like structure assembled from nanosheets consisting of nanorod building blocks was successfully synthesized by using CaCl2, NaH2PO4, and potassium sodium tartrate via a hydrothermal method at 200°C for 24 hours. The effects of heating time and heating temperature on the products were investigated. As a chelating ligand and template molecule, the potassium sodium tartrate plays a key role in the formation of hierarchically nanostructured HA. On the basis of experimental results, a possible mechanism based on soft-template and self-assembly was proposed for the formation and growth of the hierarchically nanostructured HA. Cytotoxicity experiments indicated that the hierarchically nanostructured HA had good biocompatibility. It was shown by in-vitro experiments that mesenchymal stem cells could attach to the hierarchically nanostructured HA after being cultured for 48 hours. Objective The purpose of this study was to develop facile and effective methods for the synthesis of novel hydroxyapatite (HA) with hierarchical nanostructures assembled from independent and discrete nanobuilding blocks. Methods A simple hydrothermal approach was applied to synthesize HA by using CaCl2, NaH2PO4, and potassium sodium tartrate at 200°C for 24 hours. The cell cytotoxicity of the hierarchically nanostructured HA was tested by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Results HA displayed the flower-like structure assembled from nanosheets consisting of nanorod building blocks. The potassium sodium tartrate was used as a chelating ligand, inducing the formation and self-assembly of HA nanorods. The heating time and heating temperature influenced the aggregation and morphology of HA. The cell viability did not decrease with the increasing concentration of hierarchically nanostructured HA added. Conclusion A novel, simple and reliable hydrothermal route had been developed for the synthesis of

  17. Bone Regeneration of Hydroxyapatite with Granular Form or Porous Scaffold in Canine Alveolar Sockets

    PubMed Central

    JANG, SEOK JIN; KIM, SE EUN; HAN, TAE SUNG; SON, JUN SIK; KANG, SEONG SOO; CHOI, SEOK HWA

    2017-01-01

    This study was undertaken to assess bone regeneration using hydroxyapatite (HA). The primary focus was comparison of bone regeneration between granular HA (gHA) forms and porous HA (pHA) scaffold. The extracted canine alveolar sockets were divided with three groups: control, gHA and pHA. Osteogenic effect in the gHA and pHA groups showed bone-specific surface and bone mineral density to be significantly higher than that of the control group (p<0.01). Bone volume fraction, bone mineral density, and amount of connective tissue related to disturbing osseointegration of the gHA group was higher than in the pHA group. Quantity of new bone formation of the pHA group was higher than that of the gHA group. This study demonstrated that gHA and pHA are potentially good bone substitutes for alveolar socket healing. For new bone formation during 8 weeks' post-implantation, HA with porous scaffold was superior to the granular form of HA. PMID:28438860

  18. The synergistic effect of micro/nano-structured and Cu2+-doped hydroxyapatite particles to promote osteoblast viability and antibacterial activity.

    PubMed

    Shi, Feng; Liu, Yumei; Zhi, Wei; Xiao, Dongqin; Li, Hongyu; Duan, Ke; Qu, Shuxin; Weng, Jie

    2017-06-06

    Microstructure and chemical constitution are important factors affecting the biological activity of biomaterials. This study aimed to fabricate hydroxyapatite (HAp) particles with both micro/nanohybrid structure and Cu 2+ doping to promote osteogenic differentiation and antibacterial property. In the presence of inositol hexakisphosphate (IP6), micro/nano-structured and Cu 2+ -doped HAp (HAp-IP6-Cu) microspheres were successfully fabricated via hydrothermal method. Morphological observation showed that HAp-IP6-Cu microspheres with a diameter of 3.1-4.1 μm were chrysanthemum-like and composed of nano-flakes approximately 50 nm in thickness. Compared with the HAp micro-rods or IP6 modified HAp (HAp-IP6) microspheres, HAp-IP6-Cu microspheres had a larger specific surface area, better hydrophilicity and stronger ability to adsorb bovine serum albumin. To evaluate the synergistic effects of micro/nanohybrid structure and Cu 2+ on cell behavior, rat calvarial osteoblasts (RCOs) were cultured on HAp-IP6-Cu, HAp-IP6 and HAp layers as well as their extracts, respectively. Results demonstrated that HAp-IP6-Cu layer promoted the adhesion, proliferation and osteogenic differentiation of RCOs. The cells grew on HAp-IP6-Cu and HAp-IP6 layers exhibited greater spreading than those on HAp layer. In addition, quantitative test by the agar disk diffusion technique found that HAp-IP6-Cu microspheres were effectively against S taphylococcus aureus and E scherichia coli. These results demonstrated that HAp-IP6-Cu microspheres may be a potential candidate as a bioactive and anti-infective biomaterial for bone regeneration.

  19. Activation of Osteoblastic Function on Titanium Surface with Titanium-Doped Hydroxyapatite Nanoparticle Coating: An In Vitro Study.

    PubMed

    Nakazawa, Masahiro; Yamada, Masahiro; Wakamura, Masato; Egusa, Hiroshi; Sakurai, Kaoru

    Titanium-doped hydroxyapatite (TiHA) nanoparticles contain titanium atoms in the hydroxyapatite lattice, which can physicochemically functionalize the titanium surface without modification of the surface topography. This study aimed to evaluate the physicochemical properties of machined or microroughened titanium surfaces coated with TiHA nanoparticles and the functions of osteoblasts cultured on them. Titanium disks with commercially available surface topography, such as machined or sandblasted, large-grit, and acid-etched (SLA) surfaces, were coated with TiHA. The disks with original or TiHA-coated surfaces were evaluated in topography, wettability, and chemical composition. Osteoblastic cells from rat femurs were cultured on the disks and evaluated in proliferation and differentiation. TiHA coating changed from hydrophobicity to hydrophilicity on both machined and SLA surfaces. Calcium and phosphate atoms were detected all over the surface with TiHA coating regardless of the surface topography. However, the considerable change in the inherent surface topographies was not observed on both types of surfaces after TiHA coating. Osteoblastic proliferative activity at day 4 was increased by TiHA coating on both types of surfaces. TiHA coating did not enhance expressions of bone matrix-related genes such as osteocalcin, osteopontin, bone sialoprotein, alkaline phosphatase, and collagen I. However, depositions of collagen, osteocalcin, and calcium in the culture at days 7 and 20 were increased on both types of surface topographies with TiHA coating. TiHA coating enhanced extracellular matrix formation on smooth and microroughened titanium surfaces by increasing osteoblastic proliferative activity without the deterioration of differentiation through hydrophilic and chemical functionalization.

  20. Osteogenic properties of PBLG-g-HA/PLLA nanocomposites.

    PubMed

    Liao, Lan; Yang, Shuang; Miron, Richard J; Wei, Junchao; Zhang, Yufeng; Zhang, Meng

    2014-01-01

    New development of biomaterial scaffolds remains a prominent issue for the regeneration of lost or fractured bone. Of these scaffolds, a number of bioactive polymers have been synthesized and fabricated for diverse biological roles. Although recent evidence has demonstrated that composite scaffolds such as HA/PLLA have improved properties when compared to either HA or PLLA alone, recent investigations have demonstrated that the phase compatibility between HA and PLLA layers is weak preventing optimal enhancement of the mechanical properties and making the composites prone to breakdown. In the present study, poly (γ-benzyl-L-glutamate) modified hydroxyapatite/(poly (L-lactic acid)) (PBLG-g-HA/PLLA) composite scaffolds were fabricated with improved phase compatibility and tested for their osteogenic properties in 18 Wistar female rats by analyzing new bone formation in 3 mm bilateral femur defects in vivo. At time points, 2, 4 and 8 weeks post surgery, bone formation was evaluated by µ-CT and histological analysis by comparing 4 treatment groups; 1) blank defect, 2) PLLA, 3) HA/PLLA and 4) PBLG-g-HA/PLLA scaffolds. The in vivo analysis demonstrated that new bone formation was much more prominent in HA/PLLA and PBLG-g-HA/PLLA groups as depicted by µ-CT, H&E staining and immunohistochemistry for collagen I. TRAP staining was also utilized to determine the influence of osteoclast cell number and staining intensity to the various scaffolds. No significant differences in either staining intensity or osteoclast numbers between all treatment modalities was observed, however blank defects did contain a higher number of osteoclast-like cells. The results from the present study illustrate the potential of PBLG-g-HA/PLLA scaffolds for bone tissue engineering applications by demonstrating favorable osteogenic properties.

  1. Sol-gel-derived hydroxyapatite-carbon nanotube/titania coatings on titanium substrates.

    PubMed

    Ji, Xiaoli; Lou, Weiwei; Wang, Qi; Ma, Jianfeng; Xu, Haihong; Bai, Qing; Liu, Chuantong; Liu, Jinsong

    2012-01-01

    In this paper, hydroxyapatite-carbon nanotube/titania (HA-CNT/TiO(2)) double layer coatings were successfully developed on titanium (Ti) substrates intended for biomedical applications. A TiO(2) coating was firstly developed by anodization to improve bonding between HA and Ti, and then the layer of HA and CNTs was coated on the surface by the sol-gel process to improve the biocompatibility and mechanical properties of Ti. The surfaces of double layer coatings were uniform and crack-free with a thickness of about 7 μm. The bonding strength of the HA-CNT/TiO(2) coating was higher than that of the pure HA and HA-CNT coatings. Additionally, in vitro cell experiments showed that CNTs promoted the adhesion of preosteoblasts on the HA-CNT/TiO(2) double layer coatings. These unique surfaces combined with the osteoconductive properties of HA exhibited the excellent mechanical properties of CNTs. Therefore, the developed HA-CNT/TiO(2) coatings on Ti substrates might be a promising material for bone replacement.

  2. ALP gene expression in cDNA samples from bone tissue engineering using a HA/TCP/Chitosan scaffold

    NASA Astrophysics Data System (ADS)

    Stephanie, N.; Katarina, H.; Amir, L. R.; Gunawan, H. A.

    2017-08-01

    This study examined the potential use of hydroxyapatite (HA)/tricalcium phosphate (TCP)/Chitosan as a bone tissue engineering scaffold. The potential for using HA/TCP/chitosan as a scaffold was analyzed by measuring expression of the ALP osteogenic gene in cDNA from bone biopsies from four Macaque nemestrina. Experimental conditions included control (untreated), treatment with HA/TCP 70:30, HA/TCP 50:50, and HA/TCP/chitosan. cDNA samples were measured quantitively with Real-Time PCR (qPCR) and semi-quantitively by gel electrophoresis. There were no significant differences in ALP gene expression between treatment subjects after two weeks, but the HA/TCP/chitosan treatment gave the highest level of expression after four weeks. The scaffold using the HA/TCP/chitosan combination induced a higher level of expression of the osteogenic gene ALP than did scaffold without chitosan.

  3. Hydroxyapatite implants with designed internal architecture.

    PubMed

    Chu, T M; Halloran, J W; Hollister, S J; Feinberg, S E

    2001-06-01

    Porous hydroxyapatite (HA) has been used as a bone graft material in the clinics for decades. Traditionally, the pores in these HAs are either obtained from the coralline exoskeletal patterns or from the embedded organic particles in the starting HA powder. Both processes offer very limited control on the pore structure. A new method for manufacturing porous HA with designed pore channels has been developed. This method is essentially a lost-mold technique with negative molds made with Stereolithography and a highly loaded curable HA suspension as the ceramic carrier. Implants with designed channels and connection patterns were first generated from a Computer-Aided-Design (CAD) software and Computer Tomography (CT) data. The negative images of the designs were used to build the molds on a stereolithography apparatus with epoxy resins. A 40 vol% HA suspension in propoxylated neopentyl glycol diacrylate (PNPGDA) and iso-bornyl acrylate (IBA) was formulated. HA suspension was cast into the epoxy molds and cured into solid at 85 degrees C. The molds and acrylate binders were removed by pyrolysis, followed by HA green body sintering. With this method, implants with six different channel designs were built successfully and the designed channels were reproduced in the sintered HA implants. The channels created in the sintered HA implants were between 366 microm and 968 microm in diameter with standard deviations of 50 microm or less. The porosity created by the channels were between 26% and 52%. The results show that HA implants with designed connection pattern and well controlled channel size can be built with the technique developed in this study. Copyright 2001 Kluwer Academic Publishers

  4. Reinforced Pulsed Laser-Deposited Hydroxyapatite Coating on 316 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Bajpai, Shubhra; Gupta, Ankur; Pradhan, Siddhartha Kumar; Mandal, Tapendu; Balani, Kantesh

    2014-10-01

    Hydroxyapatite (HA) is a widely used bioceramic known for its chemical similarity with that of bone and teeth (Ca/P ratio of 1.67). But, owing to its extreme brittleness, α-Al2O3 is reinforced with HA and processed as a coating via pulsed laser deposition (PLD). Reinforcement of α-Al2O3 (50 wt.%) in HA via PLD on 316L steel substrate has shown modulus increase by 4% and hardness increase by 78%, and an improved adhesion strength of 14.2 N (improvement by 118%). Micro-scratching has shown an increase in the coefficient-of-friction from 0.05 (pure HA) to 0.17 (with 50 wt.% Al2O3) with enhancement in the crack propagation resistance (CPR) up to 4.5 times. Strong adherence of PLD HA-Al2O3 coatings (~4.5 times than that of HA coating) is attributed to efficient release of stored tensile strain energy (~17 × 10-3 J/m2) in HA-Al2O3 composites, making it a potential damage-tolerant bone-replacement surface coating.

  5. Porous bodies of hydroxyapatite produced by a combination of the gel-casting and polymer sponge methods

    PubMed Central

    González Ocampo, Jazmín I.; Escobar Sierra, Diana M.; Ossa Orozco, Claudia P.

    2015-01-01

    A combination of gel-casting and polymeric foam infiltration methods is used in this study to prepare porous bodies of hydroxyapatite (HA), to provide a better control over the microstructures of samples. These scaffolds were prepared by impregnating a body of porous polyurethane foam with slurry containing HA powder, and using a percentage of solids between 40% and 50% w/v, and three different types of monomers to provide a better performance. X-Ray Diffraction (XRD), and Fourier Transformed Infrared (FTIR) and Scanning Electron Microscopy (SEM) were employed to evaluate both the powder hydroxyapatite and the scaffolds obtained. In addition, porosity and interconnectivity measurements were taken in accordance with the international norm. Bioactivity was checked using immersion tests in Simulated Body Fluids (SBF). After the sintering process of the porous bodies, the XRD results showed peaks characteristic of a pure and crystalline HA (JCPDS 9-432) as a single phase. SEM images indicate open and interconnected pores inside the material, with pore sizes between 50 and 600 μm. Also, SEM images demonstrate the relatively good bioactivity of the HA scaffolds after immersion in SBF. All results for the porous HA bodies suggest that these materials have great potential for use in tissue engineering. PMID:26966570

  6. Sol-Gel Derived Hydroxyapatite Coating on Mg-3Zn Alloy for Orthopedic Application

    NASA Astrophysics Data System (ADS)

    Singh, Sanjay; Manoj Kumar, R.; Kuntal, Kishor Kumar; Gupta, Pallavi; Das, Snehashish; Jayaganthan, R.; Roy, Partha; Lahiri, Debrupa

    2015-04-01

    In recent years, magnesium and its alloys have gained a lot of interest as orthopedic implant constituents because their biodegradability and mechanical properties are closer to that of human bone. However, one major concern with Mg in orthopedics is its high corrosion rate that results in the reduction of mechanical integrity before healing the bone tissue. The current study evaluates the sol-gel-derived hydroxyapatite (HA) coating on a selected Mg alloy (Mg-3Zn) for decreasing the corrosion rate and increasing the bioactivity of the Mg surface. The mechanical integrity of the coating is established as a function of the surface roughness of the substrate and the sintering temperature of the coating. Coating on a substrate roughness of 15-20 nm and sintering at 400°C shows the mechanical properties in similar range of bone, thus making it suitable to avoid the stress-shielding effect. The hydroxyapatite coating on the Mg alloy surface also increases corrosion resistance very significantly by 40 times. Bone cells are also found proliferating better in the HA-coated surface. All these benefits together establish the candidature of sol-gel HA-coated Mg-3Zn alloy in orthopedic application.

  7. LIBS analysis of hydroxyapatite extracted from bovine bone for Ca/P ratio measurements

    NASA Astrophysics Data System (ADS)

    Tariq, Usman; Haider, Zuhaib; Hussain, Rafaqat; Tufail, Kashif; Ali, Jalil

    2017-03-01

    Hydroxyapatite has been extensively used as a potential biocompatible ceramic in many orhtopedic applications. Hydroxyapatite is one of the members of calcium phosphate family and been used extensively as a bone substitute. The mechanical properties of hydroxyapatite itself, ceramics and bone cements prepared from hydroxyapatite vary greatly with slight variation in its Ca/P ratio. At present EDX, XRD, XRF and ICP-OES are being used for the determination of Ca/P ratio in hydroxyapatite. These techniques require special sample preparation, may also use toxic chemicals and usually are not very fast in giving the measurements. We report LIBS as a rapid alternative technique for calculation of Ca/P ratio in hydroxyapatite extracted from bovine bone (BHA). Ca/P ratio in laboratory prepared HA is calculated using LIBS and the results are validated against EDX results Ca/P ratio of the hydroxyapatite was calculated as 1.54±0.19 using LIBS while 1.63±0.03 using EDX. Ca/P ratio calculated by LIBS and EDX and showed comparable results with a difference of 5.5%. Moreover, plasma temperature and the ratio of the calcium (ion) line to calcium (atomic) line did not show significant variation in plasma conditions during measurements. The present study has demonstrated that LIBS can also be used for the determination of Ca/P ratio of hydroxyapatite and other calcium phosphates. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 24 May 2017.

  8. Properties of natural and synthetic hydroxyapatite and their surface free energy determined by the thin-layer wicking method

    NASA Astrophysics Data System (ADS)

    Szcześ, Aleksandra; Yan, Yingdi; Chibowski, Emil; Hołysz, Lucyna; Banach, Marcin

    2018-03-01

    Surface free energy is one of the parameters accompanying interfacial phenomena, occurring also in the biological systems. In this study the thin layer wicking method was used to determine surface free energy and its components for synthetic hydroxyapatite (HA) and natural one obtained from pig bones. The Raman, FTIR and X-Ray photoelectron spectroscopy, X-ray diffraction techniques and thermal analysis showed that both samples consist of carbonated hydroxyapatite without any organic components. Surface free energy and its apolar and polar components were found to be similar for both investigated samples and equalled γSTOT = 52.4 mJ/m2, γSLW = 40.2 mJ/m2 and γSAB = 12.3 mJ/m2 for the synthetic HA and γSTOT = 54.6 mJ/m2, γSLW = 40.3 mJ/m2 and γSAB = 14.3 mJ/m2 for the natural one. Both HA samples had different electron acceptor (γs+) and electron donor (γs-) parameters. The higher value of the electron acceptor was found for the natural HA whereas the electron donor one was higher for the synthetic HA

  9. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1983-01-01

    Microspheres of acrolein homopolymers and co-polymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  10. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1986-01-01

    Microspheres of acrolein homopolymers and copolymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  11. Polyacrolein microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor)

    1987-01-01

    Microspheres of acrolein homopolymers and copolymer with hydrophillic comonomers such as methacrylic acid and/or hydroxyethylmethacrylate are prepared by cobalt gamma irradiation of dilute aqueous solutions of the monomers in presence of suspending agents, especially alkyl sulfates such as sodium dodecyl sulfate. Amine or hydroxyl modification is achieved by forming adducts with diamines or alkanol amines. Carboxyl modification is effected by oxidation with peroxides. Pharmaceuticals or other aldehyde reactive materials can be coupled to the microspheres. The microspheres directly form antibody adducts without agglomeration.

  12. Bone ingrowth in bFGF-coated hydroxyapatite ceramic implants.

    PubMed

    Schnettler, Reinhard; Alt, Volker; Dingeldein, Elvira; Pfefferle, Hans-Joachim; Kilian, Olaf; Meyer, Christof; Heiss, Christian; Wenisch, Sabine

    2003-11-01

    This experimental study was performed to evaluate angiogenesis, bone formation, and bone ingrowth in response to osteoinductive implants of bovine-derived hydroxyapatite (HA) ceramics either uncoated or coated with basic fibroblast growth factor (bFGF) in miniature pigs. A cylindrical bone defect was created in both femur condyles of 24 miniature pigs using a saline coated trephine. Sixteen of the 48 defects were filled with HA cylinders coated with 50 microg rhbFG, uncoated HA cylinders, and with autogenous transplants, respectively. Fluorochrome labelled histological analysis, histomorphometry, and scanning electron microscopy were performed to study angiogenesis, bone formation and bone ingrowth. Complete bone ingrowth into bFGF-coated HA implants and autografts was seen after 34 days compared to 80 days in the uncoated HA group. Active ring-shaped areas of fluorochrome labelled bone deposition with dynamic bone remodelling were found in all cylinders. New vessels could be found in all cylinders. Histomorphometric analysis showed no difference in bone ingrowth over time between autogenous transplants and bFGF-coated HA implants. The current experimental study revealed comparable results of bFGF-coated HA implants and autogenous grafts regarding angiogenesis, bone synthesis and bone ingrowth.

  13. DNA damage evaluation of hydroxyapatite on fibroblast cell L929 using the single cell gel electrophoresis assay.

    PubMed

    Rajab, N F; Yaakob, T A; Ong, B Y; Hamid, M; Ali, A M; Annuar, B O; Inayat-Hussain, S H

    2004-05-01

    Hydroxyapatite is the main component of the bone which is a potential biomaterial substance that can be applied in orthopaedics. In this study, the biocompatibility of this biomaterial was assessed using an in vitro technique. The cytotoxicity and genotoxicity effect of HA2 and HA3 against L929 fibroblast cell was evaluated using the MTT Assay and Alkaline Comet Assay respectively. Both HA2 and HA3 compound showed low cytotoxicity effect as determined using MTT Assay. Cells viability following 72 hours incubation at maximum concentration of both HA2 and HA3 (200 mg/ml) were 75.3 +/- 8.8% and 86.7 +/- 13.1% respectively. However, the cytotoxicity effect of ZnSO4.7H2O as a positive control showed an IC50 values of 46 mg/ml (160 microM). On the other hand, both HA2 and HA3 compound showed a slight genotoxicity effect as determined using the Alkaline Comet Assay following incubation at the concentration 200 mg/ml for 72 hours. This assay has been widely used in genetic toxicology to detect DNA strand breaks and alkali-labile site. The percentage of the cells with DNA damage for both substance was 27.7 +/- 1.3% and 15.6 +/- 1.0% for HA2 and HA3 respectively. Incubation of the cells for 24 hours with 38 microg/ml (IC25) of positive control showed an increase in percentage of cells with DNA damage (67.5 +/- 0.7%). In conclusion, our study indicated that both hydroxyapatite compounds showed a good biocompatibility in fibroblast cells.

  14. Optical study of plasma sprayed hydroxyapatite coatings deposited at different spray distance

    NASA Astrophysics Data System (ADS)

    Belka, R.; Kowalski, S.; Żórawski, W.

    2017-08-01

    Series of hydroxyapatite (HA) coatings deposited on titanium substrate at different spray (plasma gun to workpiece) distance were investigated. The optical methods as dark field confocal microscopy, Raman/PL and UV-VIS spectroscopy were used for study the influence of deposition process on structural degradation of HA precursor. The hydroxyl group concentration was investigated by study the OH mode intensity in the Raman spectra. Optical absorption coefficients at near UV region were analyzed by Diffuse Reflectance Spectroscopy. PL intensity observed during Raman measurement was also considered as relation to defects concentration and degradation level. It was confirmed the different gunsubstrate distance has a great impact on structure of deposited HA ceramics.

  15. Influence of Magnesium Ion Substitution on Structural and Thermal Behavior of Nanodimensional Hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Batra, Uma; Kapoor, Seema; Sharma, Sonia

    2013-06-01

    Hydroxyapatite (HA), incorporating small amount of magnesium, shows attractive biological performance in terms of improved bone metabolism, osteoblast and osteoclast activity, and bone in-growth. This article reports a systematic investigation on the influence of magnesium (Mg) substitution on structural and thermal behavior of nanodimensional HA. HA and Mg-substituted HA nanopowders were synthesized through sol-gel route. The morphology and size of nanopowders were characterized by transmission electron microscopy. The BET surface area was evaluated from N2 adsorption isotherms. Structural analysis and thermal behavior were investigated by means of Fourier transform infrared spectroscopy, x-ray diffraction, thermogravimetry, and differential thermal analysis. As-synthesized powders consisted of flake-like agglomerates of HA and calcium-deficient HA. The incorporation of magnesium in HA resulted in decrease of crystallite size, crystallinity, and lattice parameters a and c and increase in BET surface area. β-tricalcium phosphate formation occured at lower calcination temperature in Mg-substituted HA than HA.

  16. The thermal stability of hydroxyapatite in biphasic calcium phosphate ceramics.

    PubMed

    Nilen, R W N; Richter, P W

    2008-04-01

    Biphasic calcium phosphate ceramics (BCP) comprising a mix of non-resorbable hydroxyapatite (HA) and resorbable beta-tricalcium phosphate (beta-TCP) are particularly suitable materials for synthetic bone substitute applications. In this study, HA synthesised by solid state reaction was mechanically mixed with beta-TCP, then sintered to form a suite of BCP materials with a wide range of HA/beta-TCP phase content ratios. The influence of sintering temperature and composition on the HA thermal stability was quantified by X-ray diffraction (XRD). The pre-sinter beta-TCP content was found to strongly affect the post-sinter HA/beta-TCP ratio by promoting the thermal decomposition of HA to beta-TCP, even at sintering temperatures as low as 850 degrees C. For BCP material with pre-sinter HA/beta-TCP = 40/60 wt%, approximately 80% of the HA decomposed to beta-TCP during sintering at 1000 degrees C. Furthermore, the HA content appeared to influence the reverse transformation of alpha-TCP to beta-TCP expected upon gradual cooling from sintering temperatures greater than 1125 degrees C. Because the HA/beta-TCP ratio dominantly determines the rate and extent of BCP resorption in vivo, the possible thermal decomposition of HA during BCP synthesis must be considered, particularly if high temperature treatments are involved.

  17. Bone tissue engineering with a collagen–hydroxyapatite scaffold and culture expanded bone marrow stromal cells

    PubMed Central

    Villa, Max M.; Wang, Liping; Huang, Jianping; Rowe, David W.; Wei, Mei

    2015-01-01

    Osteoprogenitor cells combined with supportive biomaterials represent a promising approach to advance the standard of care for bone grafting procedures. However, this approach faces challenges, including inconsistent bone formation, cell survival in the implant, and appropriate biomaterial degradation. We have developed a collagen–hydroxyapatite (HA) scaffold that supports consistent osteogenesis by donor derived osteoprogenitors, and is more easily degraded than a pure ceramic scaffold. Herein, the material properties are characterized as well as cell attachment, viability, and progenitor distribution in vitro. Furthermore, we examined the biological performance in vivo in a critical-size mouse calvarial defect. To aid in the evaluation of the in-house collagen–HA scaffold, the in vivo performance was compared with a commercial collagen–HA scaffold (Healos®, Depuy). The in-house collagen–HA scaffold supported consistent bone formation by predominantly donor-derived osteoblasts, nearly completely filling a 3.5 mm calvarial defect with bone in all samples (n=5) after 3 weeks of implantation. In terms of bone formation and donor cell retention at 3 weeks postimplantation, no statistical difference was found between the in-house and commercial scaffold following quantitative histomorphometry. The collagen–HA scaffold presented here is an open and well-defined platform that supports robust bone formation and should facilitate the further development of collagen–hydroxyapatite biomaterials for bone tissue engineering. PMID:24909953

  18. Hydrothermal fabrication of hydroxyapatite on the PEG-grafted surface of wood from Chinese Glossy Privet

    NASA Astrophysics Data System (ADS)

    Wang, Ning; Cai, Chuanjie; Cai, Dongqing; Cheng, Junjie; Li, Shengli; Wu, Zhengyan

    2012-10-01

    Wood-hydroxyapatite composite material was developed by depositing hydrated calcium hydrogen phosphate (HCHP) on the surface of wood from Chinese Glossy Privet (CGP) with polyethylene glycol (PEG, HO(CH2CH2O)nH) as the grafting agent and subsequent hydrothermal vapor treatment. The results illustrated that HCHP could adhere quickly and strongly on the PEG-grafted wood surface. Moreover, this HCHP could be efficiently transformed to hydroxyapatite (HA, Ca10(PO4)6(OH)2) by hydrothermal vapor treatment. IR, XRD analysis and SEM observation indicated that the fabricated hydroxyapatite was pure and its morphology was uniform and microporous. This work provides a new fabricating approach of biocompatible material which may have some potential applications as bone-repairing material.

  19. Improved cell viability and hydroxyapatite growth on nitrogen ion-implanted surfaces

    NASA Astrophysics Data System (ADS)

    Shafique, Muhammad Ahsan; Murtaza, G.; Saadat, Shahzad; Uddin, Muhammad K. H.; Ahmad, Riaz

    2017-08-01

    Stainless steel 306 is implanted with various doses of nitrogen ions using a 2 MV pelletron accelerator for the improvement of its surface biomedical properties. Raman spectroscopy reveals incubation of hydroxyapatite (HA) on all the samples and it is found that the growth of incubated HA is greater in higher ion dose samples. SEM profiles depict uniform growth and greater spread of HA with higher ion implantation. Human oral fibroblast response is also found consistent with Raman spectroscopy and SEM results; the cell viability is found maximum in samples treated with the highest (more than 300%) dose. XRD profiles signified greater peak intensity of HA with ion implantation; a contact angle study revealed hydrophilic behavior of all the samples but the treated samples were found to be lesser hydrophilic compared to the control samples. Nitrogen implantation yields greater bioactivity, improved surface affinity for HA incubation and improved hardness of the surface.

  20. New nano-hydroxyapatite in bone defect regeneration: A histological study in rats.

    PubMed

    Kubasiewicz-Ross, Paweł; Hadzik, Jakub; Seeliger, Julia; Kozak, Karol; Jurczyszyn, Kamil; Gerber, Hanna; Dominiak, Marzena; Kunert-Keil, Christiane

    2017-09-01

    Many types of bone substitute materials are available on the market. Researchers are refining new bone substitutes to make them comparable to autologous grafting materials in treatment of bone defects. The purpose of the study was to evaluate the osseoconductive potential and bone defect regeneration in rat calvaria bone defects treated with new synthetic nano-hydroxyapatite. The study was performed on 30 rats divided into 5 equal groups. New preproduction of experimental nano-hydroxyapatite material by NanoSynHap (Poznań, Poland) was tested and compared with commercially available materials. Five mm critical size defects were created and filled with the following bone grafting materials: 1) Geistlich Bio-Oss ® ; 2) nano-hydroxyapatite+β-TCP; 3) nano-hydroxyapatite; 4) nano-hydroxyapatite+collagen membrane. The last group served as controls without any augmentation. Bone samples from calvaria were harvested for histological and micro-ct evaluation after 8 weeks. New bone formation was observed in all groups. Histomorphometric analysis revealed an amount of regenerated bone between 34.2 and 44.4% in treated bone defects, whereas only 13.0% regenerated bone was found in controls. Interestingly, in group 3, no significant particles of the nano-HA material were found. In contrast, residual bone substitute material could be detected in all other test groups. Micro-CT study confirmed the results of the histological examinations. The new nano-hydroxyapatite provides comparable results to other grafts in the field of bone regeneration. Copyright © 2017 Elsevier GmbH. All rights reserved.

  1. Structural characterization of nanocrystalline hydroxyapatite and adhesion of pre-osteoblast cells

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaolong; Eibl, Oliver; Berthold, Christoph; Scheideler, Lutz; Geis-Gerstorfer, Jürgen

    2006-06-01

    Nanocrystalline hydroxyapatite (Nano HA), a prototype of minerals of bones and teeth, attracts increasing interest in medicine and dentistry. Different parameters for synthesis and post-treatment were investigated to determine their effects on crystallinity of nano HA, and in vitro cell responses to nano HA were studied. XRD and TEM analyses indicate that the crystallinity of nano HA synthesized by a chemical method was within the range of 15-50 nm, which is adapted to natural minerals of hard tissues. Increasing the ageing temperature significantly increased the crystallinity of nano HA, while lengthening the ageing time or varying the post-ageing drying process did not have any influence on its crystallinity. Nano HA annealed between 300 and 900 °C showed a small increase in crystallinity with increasing annealing temperature due to the long-range ordering effect. Cell attachment and spreading on nano HA were lower than those on pure titanium, and decreased as the crystallinity of nano HA increased. However, cells on nano HA demonstrated well-developed filopodia and lamelliopodia, which facilitate migration of the cells on it. This may benefit osteogenesis at the interface between bone and nano HA in vivo.

  2. Nano hydroxyapatite-blasted titanium surface affects pre-osteoblast morphology by modulating critical intracellular pathways.

    PubMed

    Bezerra, Fábio; Ferreira, Marcel R; Fontes, Giselle N; da Costa Fernandes, Célio Jr; Andia, Denise C; Cruz, Nilson C; da Silva, Rodrigo A; Zambuzzi, Willian F

    2017-08-01

    Although, intracellular signaling pathways are proposed to predict the quality of cell-surface relationship, this study addressed pre-osteoblast behavior in response to nano hydroxyapatite (HA)-blasted titanium (Ti) surface by exploring critical intracellular pathways and pre-osteoblast morphological change. Physicochemical properties were evaluated by atomic force microscopy (AFM) and wettability considering water contact angle of three differently texturized Ti surfaces: Machined (Mac), Dual acid-etching (DAE), and nano hydroxyapatite-blasted (nHA). The results revealed critical differences in surface topography, impacting the water contact angle and later the osteoblast performance. In order to evaluate the effect of those topographical characteristics on biological responses, we have seeded pre-osteoblast cells on the Ti discs for up to 4 h and subjected the cultures to biological analysis. First, we have observed pre-osteoblasts morphological changes resulting from the interaction with the Ti texturized surfaces whereas the cells cultured on nHA presented a more advanced spreading process when compared with the cells cultured on the other surfaces. These results argued us for analyzing the molecular machinery and thus, we have shown that nHA promoted a lower Bax/Bcl2 ratio, suggesting an interesting anti-apoptotic effect, maybe explained by the fact that HA is a natural element present in bone composition. Thereafter, we investigated the potential effect of those surfaces on promoting pre-osteoblast adhesion and survival signaling by performing crystal violet and immunoblotting approaches, respectively. Our results showed that nHA promoted a higher pre-osteoblast adhesion supported by up-modulating FAK and Src activations, both signaling transducers involved during eukaryotic cell adhesion. Also, we have shown Ras-Erk stimulation by the all evaluated surfaces. Finally, we showed that all Ti-texturing surfaces were able to promote osteoblast differentiation

  3. Strength and fatigue properties of three-step sintered dense nanocrystal hydroxyapatite bioceramics

    NASA Astrophysics Data System (ADS)

    Guo, Wen-Guang; Qiu, Zhi-Ye; Cui, Han; Wang, Chang-Ming; Zhang, Xiao-Jun; Lee, In-Seop; Dong, Yu-Qi; Cui, Fu-Zhai

    2013-06-01

    Dense hydroxyapatite (HA) ceramic is a promising material for hard tissue repair due to its unique physical properties and biologic properties. However, the brittleness and low compressive strength of traditional HA ceramics limited their applications, because previous sintering methods produced HA ceramics with crystal sizes greater than nanometer range. In this study, nano-sized HA powder was employed to fabricate dense nanocrystal HA ceramic by high pressure molding, and followed by a three-step sintering process. The phase composition, microstructure, crystal dimension and crystal shape of the sintered ceramic were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Mechanical properties of the HA ceramic were tested, and cytocompatibility was evaluated. The phase of the sintered ceramic was pure HA, and the crystal size was about 200 nm. The compressive strength and elastic modulus of the HA ceramic were comparable to human cortical bone, especially the good fatigue strength overcame brittleness of traditional sintered HA ceramics. Cell attachment experiment also demonstrated that the ceramics had a good cytocompatibility.

  4. Interfacial characteristics and determination of cohesive and adhesive strength of plasma-coated hydroxyapatite via nanoindentation and microscratch techniques.

    PubMed

    McManamon, Colm; de Silva, Johann P; Power, John; Ramirez-Garcia, Sonia; Morris, Michael A; Cross, Graham L W

    2014-09-30

    We investigate the chemical composition and mechanical properties of plasma-deposited hydroxyapatite on grit-blasted Ti-6Al-4V coupons as models of typical prosthetic hip implants. Nanoindentation is used to extract the mechanical properties of the hydroxyapatite (HA) coating and to evaluate the behavior of the material as a function of distance from the interface. A microscratch technique was used to determine parameters of cohesive and adhesive failure of the material that are critical in determining the functionality of these biomedical devices. This delamination method has not been studied in detail before and is usually considered to be unsuitable because of the thickness of the HA and the roughness of the substrate. However, through cross-section analysis of the scratch test, we can determine the point at which the HA delaminates from the substrate. It was concluded that spallation occurs locally, and there is no evidence of gross spallation, indicating that the coating is well adhered to the substrate.

  5. Hydroxyapatite nanocrystals functionalized with alendronate as bioactive components for bone implant coatings to decrease osteoclastic activity

    NASA Astrophysics Data System (ADS)

    Bosco, Ruggero; Iafisco, Michele; Tampieri, Anna; Jansen, John A.; Leeuwenburgh, Sander C. G.; van den Beucken, Jeroen J. J. P.

    2015-02-01

    The integration of bone implants within native bone tissue depends on periprosthetic bone quality, which is severely decreased in osteoporotic patients. In this work, we have synthesized bone-like hydroxyapatite nanocrystals (nHA) using an acid-base neutralization reaction and analysed their physicochemical properties. Subsequently, we have functionalized the nHA with alendronate (nHAALE), a well-known bisphosphonate drug used for the treatment of osteoporosis. An in vitro osteoclastogenesis test was carried out to evaluate the effect of nHAALE on the formation of osteoclast-like cells from monocytic precursor cells (i.e. RAW264.7 cell line) showing that nHAALE significantly promoted apoptosis of osteoclast-like cells. Subsequently, nHA and nHAALE were deposited on titanium disks using electrospray deposition (ESD), for which characterisation of the deposited coatings confirmed the presence of alendronate in nHAALE coatings with nanoscale thickness of about 700 nm. These results indicate that alendronate linked to hydroxyapatite nanocrystals has therapeutic potential and nHAALE can be considered as an appealing coating constituent material for orthopaedic and oral implants for application in osteoporotic patients.

  6. Mechanisms of uranium interactions with hydroxyapatite: Implications for groundwater remediation

    USGS Publications Warehouse

    Fuller, C.C.; Bargar, J.R.; Davis, J.A.; Piana, M.J.

    2002-01-01

    The speciation of U(VI) sorbed to synthetic hydroxyapatite was investigated using a combination of U LIII-edge XAS, synchrotron XRD, batch uptake measurements, and SEM-EDS. The mechanisms of U(VI) removal by apatite were determined in order to evaluate the feasibility of apatitebased in-situ permeable reactive barriers (PRBs). In batch U(VI) uptake experiments with synthetic hydroxyapatite (HA), near complete removal of dissolved uranium (>99.5%) to <0.05 ??M was observed over a range of total U(VI) concentrations up to equimolar of the total P in the suspension. XRD and XAS analyses of U(VI)-reacted HA at sorbed concentrations ???4700 ppm U(VI) suggested that uranium(VI) phosphate, hydroxide, and carbonate solids were not present at these concentrations. Fits to EXAFS spectra indicate the presence of Ca neighbors at 3.81 A??. U-Ca separation, suggesting that U(VI) adsorbs to the HA surfaces as an inner-sphere complex. Uranium(VI) phosphate solid phases were not detected in HA with 4700 ppm sorbed U(VI) by backscatter SEM or EDS, in agreement with the surface complexation process. In contrast, U(VI) speciation in samples that exceeded 7000 ppm sorbed U(VI) included a crystalline uranium(VI) phosphate solid phase, identified as chernikovite by XRD. At these higher concentrations, a secondary, uranium(VI) phosphate solid was detected by SEM-EDS, consistent with chernikovite precipitation. Autunite formation occurred at total U:P molar ratios ???0.2. Our findings provide a basis for evaluating U(VI) sorption mechanisms by commercially available natural apatites for use in development of PRBs for groundwater U(VI) remediation.

  7. Hydroxyapatite coatings produced on commercially pure titanium by micro-arc oxidation.

    PubMed

    Huang, Yong; Wang, Yingjun; Ning, Chengyun; Nan, Kaihui; Han, Yong

    2007-09-01

    A porous hydroxyapatite (HA) coating on commercially pure titanium was prepared by micro-arc oxidation (MAO) in electrolytic solution containing calcium acetate and beta-glycerol phosphate disodium salt pentahydrate (beta-GP). The thickness, phase, composition morphology and biocompatibility of the oxide coating were characterized by x-ray diffraction (XRD), electron probe microanalysis (EPMA), scanning electron microscopy (SEM) with an energy dispersive x-ray spectrometer (EDS) and cell culture. The thickness of the MAO film was about 20 microm, and the coating was porous and uneven without any apparent interface to the titanium substrates. The result of XRD showed that the porous coating was made up of HA film. The favorable osteoblast cell affinity gives HA film good biocompatibility. HA coatings are expected to have significant uses for medical applications such as dental implants and artificial bone joints.

  8. Hydroxyapatite clay for gap filling and adequate bone ingrowth.

    PubMed

    Maruyama, M; Terayama, K; Ito, M; Takei, T; Kitagawa, E

    1995-03-01

    In uncemented total hip arthroplasty, a complete filling of the gap between femoral prosthesis and the host bone is difficult and defects would remain, because the anatomy of the reamed intramedullary canal cannot fit the prosthesis. Therefore, it seems practical to fill the gap with a clay containing hydroxyapatite (HA), which has an osteoconductive character. The clay (HA clay) is made by mixing HA granules (size 0.1 mm or more) having a homogeneous pore distribution and a porosity of 35-48 vol%, and a viscous substance such as a saline solution of sodium alginate (SSSA). In the first experiment, the ratio of HA granules and sodium alginate in SSSA is set for the same handling properties of HA clay and polymethylmethacrylate bone cement (standard viscosity) before hardening. As a result, the ratio is set for 55 wt% of HA in the clay and 12.5 wt% of sodium alginate in SSSA (i.e., HA:sodium alginate:saline solution = 9.8:1:7). In the second study, the gap between the femoral stem and bone model is completely filled with HA clay. However, the gap is not filled only with HA granules or HA granules mixed with saline solution. In the third animal experiment, using an unloaded model, histology shows that HA clay has an osteoconductive property bridging the gap between the implant and the cortical bone without any adverse reaction. HA clay is considered a useful biomaterial to fill the gap with adequate bone ingrowth.

  9. Interface activation and surface characteristics of Ti/TiN/HA coated sintered stainless steels

    NASA Astrophysics Data System (ADS)

    Choe, Han-Cheol; Ko, Yeong-Mu

    2006-02-01

    Interface activation and surface characteristics of Ti/TiN/HA film coated sintered stainless steels (SSS) have been investigated by electrochemical and biocompatibility tests. HA (hydroxyapatite), Ti, and Ti/TiN film coatings were applied using electron-beam deposition method (EB-PVD). Ti, Ti/TiN, and Ti/TiN/HA film coated surfaces and layers were investigated by SEM and XPS. The coated films showed micro-columnar structure, and Ti/TiN/HA films were denser than Ti or HA-only film. The corrosion resistance of the HA coating was similar to that of Ti/TiN/HA film coating when Cu content reached 4 wt.%, but the corrosion resistance of the HA coating decreased when Cu content increased from 4 wt.% in 0.9% NaCl solution. Therefore, HA-only coating could ensure corrosion resistance when Cu content does not exceed 4 wt.%. The results of biocompatibility tests of SSS on dogs showed that bone formation and biocompatibility were favorable when Cu content did not exceed 4 wt.%. The biocompatibility with bone was generally favorable in Ti/TiN/HA film coating and HA-only coating, while bone formation was somewhat faster for the HA film coated surface than for the Ti/TiN/HA film coating. Also, good cell growth and osseointegration without toxicity were observed.

  10. Bone integration capability of a series of strontium-containing hydroxyapatite coatings formed by micro-arc oxidation.

    PubMed

    Yan, Jun; Sun, Ji-Feng; Chu, Paul K; Han, Yong; Zhang, Yu-Mei

    2013-09-01

    Strontium-containing hydroxyapatites (Sr-HA) combine the desirable bone regenerative properties of hydroxyapatites (HA) with anabolic and anti-catabolic effects of strontium cations. In the present work, a series of Sr(y)HA [Sr(y)Ca(10-y)(PO4)6(OH)2; y = 0, 0.5, 1, 2] coatings on titanium are produced by micro-arc oxidation (MAO), and the effects of the in vivo osseointegration ability of the coatings are investigated by using a rabbit model. All samples are subjected to biomechanical, surface elemental, micro-CT and histological analysis after 4 and 12 weeks of healing. The obtained results show that the MAO-formed coatings exhibit a microporous network structure composed of Sr(y)HA/Sr(y)HA-Sr(x)Ca(1-x)TiO3/Sr(x)Ca(1-x)TiO3-TiO2 multilayers, in which the outer Sr(y)HA and intermediate Sr(y)HA-Sr(x)Ca(1-x)TiO3 layers have a nanocrystalline structure. All Sr-HA coated implants induce marked improvements in the behavior of bone formation, quantity and quality of bone tissue around the implants than the control HA implant and in particular, the 20%Sr-HA coating promotes early bone formation as identified by polyfluorochrome sequential labeling. The bone-to-implant contact is increased by 46% (p < 0.05) and the pull-out strength is increased by 103% over the HA group (p < 0.01). Extensive areas of mineralized tissue densely deposit on the 20%Sr-HA coating after biomechanical testing, and the greatest improvement of bone microarchitecture are observed around the 20%Sr-HA implant. The identified biological parameters successfully demonstrate the osteoconductivity of 20%Sr-HA surfaces, which results not only in an acceleration but also an improvement of bone-implant integration. The study demonstrates the immense potential of 20%Sr-HA coatings in dental and orthopedic applications. Copyright © 2012 Wiley Periodicals, Inc.

  11. A novel jet-based nano-hydroxyapatite patterning technique for osteoblast guidance

    PubMed Central

    Li, Xiang; Koller, Garrit; Huang, Jie; Di Silvio, Lucy; Renton, Tara; Esat, Minoo; Bonfield, William; Edirisinghe, Mohan

    2010-01-01

    Surface topography is well known to play a crucial role in influencing cellular responses to an implant material and is therefore important in bone tissue regeneration. A novel jet-based patterning technique, template-assisted electrohydrodynamic atomization spraying, was recently devised to control precisely the surface structure as well as its dimensions. In the present study, a detailed investigation of this patterning process was carried out. A range of nano-hydroxyapatite (nHA) line-shaped patterns <20 µm in width were successfully deposited on a commercially pure Ti surface by controlling the flow of an nHA suspension in an electric field. In vitro studies showed that the nHA patterns generated are capable of regulating the human osteoblast cell attachment and orientation. PMID:19493897

  12. Ultrasound-assisted fabrication of a biocompatible magnetic hydroxyapatite.

    PubMed

    Zhou, Gang; Song, Wei; Hou, Yongzhao; Li, Qing; Deng, Xuliang; Fan, Yubo

    2014-10-01

    This work describes the fabrication and characterization of a biocompatible magnetic hydroxyapatite (HA) using an ultrasound-assisted co-precipitation method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM) were used to characterize the structure and chemical composition of the produced samples. The M-H loops of synthesized materials were traced using a vibrating sample magnetometer (VSM) and the biocompatibility was evaluated by cell culture and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Furthermore, in vivo histopathological examinations were used to evaluate the potential toxicological effects of Fe₃O₄-HA composites on kidney of SD rats injected intraperitoneally with Fe₃O₄-HA particles. The results showed that magnetic iron oxide particles first replace OH ions of HA, which are parallel to the c axis, and then enter the HA crystal lattice which produces changes in the crystal surface of HA. Chemical bond interaction was observed between PO₄³⁻ groups of HA and iron ions of Fe₃O₄. The saturation magnetization (MS ) of Fe₃O₄-HA composites was 46.36 emu/g obtained from VSM data. Cell culture and MTT assays indicated that HA could affect the growth and proliferation of HEK-293 cells. This Fe₃O₄-HA composite produced no negative effects on cell morphology, viability, and proliferation and exhibited remarkable biocompatibility. Moreover, no inflammatory cell infiltration was observed in kidney histopathology slices. Therefore, this study succeeds to develop a Fe₃O₄-HA composite as a prospective biomagnetic material for future applications. © 2013 Wiley Periodicals, Inc.

  13. 3D silicon doped hydroxyapatite scaffolds decorated with Elastin-like Recombinamers for bone regenerative medicine.

    PubMed

    Vila, Mercedes; García, Ana; Girotti, Alessandra; Alonso, Matilde; Rodríguez-Cabello, Jose Carlos; González-Vázquez, Arlyng; Planell, Josep A; Engel, Elisabeth; Buján, Julia; García-Honduvilla, Natalio; Vallet-Regí, María

    2016-11-01

    The current study reports on the manufacturing by rapid prototyping technique of three-dimensional (3D) scaffolds based on silicon substituted hydroxyapatite with Elastin-like Recombinamers (ELRs) functionalized surfaces. Silicon doped hydroxyapatite (Si-HA), with Ca 10 (PO 4 ) 5.7 (SiO 4 ) 0.3 (OH) 1.7 h 0.3 nominal formula, was surface functionalized with two different types of polymers designed by genetic engineering: ELR-RGD that contain cell attachment specific sequences and ELR-SN A 15/RGD with both hydroxyapatite and cells domains that interact with the inorganic phase and with the cells, respectively. These hybrid materials were subjected to in vitro assays in order to clarify if the ELRs coating improved the well-known biocompatible and bone regeneration properties of calcium phosphates materials. The in vitro tests showed that there was a total and homogeneous colonization of the 3D scaffolds by Bone marrow Mesenchymal Stromal Cells (BMSCs). In addition, the BMSCs were viable and able to proliferate and differentiate into osteoblasts. Bone tissue engineering is an area of increasing interest because its main applications are directly related to the rising life expectancy of the population, which promotes higher rates of several bone pathologies, so innovative strategies are needed for bone tissue regeneration therapies. Here we use the rapid prototyping technology to allow moulding ceramic 3D scaffolds and we use different bio-polymers for the functionalization of their surfaces in order to enhance the biological response. Combining the ceramic material (silicon doped hydroxyapatite, Si-HA) and the Elastin like Recombinamers (ELRs) polymers with the presence of the integrin-mediate adhesion domain alone or in combination with SNA15 peptide that possess high affinity for hydroxyapatite, provided an improved Bone marrow Mesenchymal Stromal Cells (BMSCs) differentiation into osteoblastic linkage. Copyright © 2016 Acta Materialia Inc. Published by Elsevier

  14. HA and double-layer HA-P2O5/CaO glass coatings: influence of chemical composition on human bone marrow cells osteoblastic behavior.

    PubMed

    Ferraz, M P; Fernandes, M H; Santos, J D; Monteiro, F J

    2001-07-01

    Human osteoblastic bone marrow derived cells were cultured for 28 days onto the surface of a glass reinforced hydroxyapatite (HA) composite and a commercial type HA plasma sprayed coatings, both in the "as-received" condition and after an immersion treatment with culture medium during 21 days. Cell proliferation and differentiation were analyzed as a function of the chemical composition of the coatings and the immersion treatment. Cell attachment, growth and differentiation of osteoblastic bone marrow cells seeded onto "as-received" plasma sprayed coatings were strongly affected by the time-dependent variation of the surface structure occurring during the first hours of culture. Initial interactions leading to higher amounts of adsorbed protein and zeta potential shifts towards negative charges appeared to result in surface structures with better biological performance. Cultures grown onto the pretreated coatings showed higher rate of cell proliferation and increased functional activity, as compared to those grown onto the corresponding "as-received" materials. However, the cell behavior was similar in the glass composite and HA coatings. The results showed that the glass composites present better characteristics for bone cell growth and function than HA. In addition, this work also provide evidence that the biological performance of the glass composites can be modulated and improved by manipulations in the chemical composition, namely in the content of glass added to HA. Copyright 2001 Kluwer Academic Publishers

  15. POE/PLGA composite microspheres: formation and in vitro behavior of double walled microspheres.

    PubMed

    Yang, Yi-Yan; Shi, Meng; Goh, Suat-Hong; Moochhala, Shabbir M; Ng, Steve; Heller, Jorge

    2003-03-07

    The poly(ortho ester) (POE) and poly(D,L-lactide-co-glycolide) 50:50 (PLGA) composite microspheres were fabricated by a water-in-oil-in-water (w/o/w) double emulsion process. The morphology of the composite microspheres varied depending on POE content. When the POE content was 50, 60 or 70% in weight, the double walled microspheres with a dense core of POE and a porous shell of PLGA were formed. The formation of the double walled POE/PLGA microspheres was analysed. Their in vitro degradation behavior was characterized by scanning electron microscopy, gel permeation chromatography, Fourier-transform infrared microscopy and nuclear magnetic resonance spectroscopy (NMR). It was found that compared to the neat POE or PLGA microspheres, distinct degradation mechanism was achieved in the double walled POE/PLGA microspheres system. The degradation of the POE core was accelerated due to the acidic microenvironment produced by the hydrolysis of the outer PLGA layer. The formation of hollow microspheres became pronounced after the first week in vitro. 1H NMR spectra showed that the POE core was completely degraded after 4 weeks. On the other hand, the outer PLGA layer experienced slightly retarded degradation after the POE core disappeared. PLGA in the double walled microspheres kept more than 32% of its initial molecular weight over a period of 7 weeks.

  16. Elaboration of the hydroxyapatite with different precursors and application for the retention of the lead.

    PubMed

    Meski, S; Ziani, S; Khireddine, H; Yataghane, F; Ferguene, N

    2011-01-01

    Carbonate hydroxyapatite (CHAP) was synthesized from different precursors; synthetic (CaCO3 and Ca(OH)2) and natural (egg shell before and after calcinations at 900 degrees C) under different conditions and characterized by using TG/DTG analysis, X-ray powder diffraction (XRD) method and Fourier transform infrared (FT-IR) spectroscopy techniques. The results of these analyses indicate that the four powders present the same structure of hydroxyapatite. Furthermore the four powders obtained were used for the retention of lead. The results obtained indicated that all powders present high adsorption capacity for lead, but from environmental and economic views, the hydroxyapatite synthesized from eggshell no calcined (HA2) is most advantageous. The influence of different sorption parameters, such as: initial metal concentration, equilibration time, solution pH and sorbent dosage was studied and discussed.

  17. Improving the degradation behavior and in vitro biological property of nano-hydroxyapatite surface- grafted with the assist of citric acid.

    PubMed

    Jiang, Liuyun; Jiang, Lixin; Xiong, Chengdong; Su, Shengpei

    2016-10-01

    To obtain ideal nano-hydroxyapatite(n-HA) filler for poly(lactide-co-glycolide) (PLGA), a new surface-grafting with the assist of citric acid for nano-hydroxyapatite (n-HA) was designed, and the effect of n-HA surface-grafted with or without citric acid on in vitro degradation behavior and cells viability was studied by the experiments of soaking in simulated body fluid (SBF) and incubating with human osteoblast-like cells (MG-63). The change of pH value, tensile strength reduction, the surface deposits, cells attachment and proliferation of samples during the soaking and incubation were investigated by means of pH meter, electromechanical universal tester, scanning electron microscope (SEM) coupled with energy-dispersive spectro-scopy (EDS), fluorescence microscope and MTT method. The results showed that the introduction of citric acid not only delayed the strength reduction during the degradation by inhibiting the detachment of n-HA from PLGA, but also endowed it better cell attachment and proliferation, suggesting that the n-HA surface-grafted with the assist of citric acid was an important bioactive ceramic fillers for PLGA used as bone materials. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. A combined chitosan/nano-size hydroxyapatite system for the controlled release of icariin.

    PubMed

    Fan, Junjun; Bi, Long; Wu, Tao; Cao, Liangguo; Wang, Dexin; Nan, Kaihui; Chen, Jingdi; Jin, Dan; Jiang, Shan; Pei, Guoxian

    2012-02-01

    Icariin, a plant-derived flavonol glycoside, has been proved as an osteoinductive agent for bone regeneration. For this reason, we developed an icariin-loaded chitosan/nano-sized hydroxyapatite (IC-CS/HA) system which controls the release kinetics of icariin to enhance bone repairing. First, by Fourier transform infrared spectroscopy, we found that icariin was stable in the system developed without undergoing any chemical changes. On the other hand, X-ray diffraction, scanning electron microscopy and mechanical test revealed that the introduction of icariin did not remarkably change the phase, morphology, porosity and mechanical strength of the CS/HA composite. Then the hydrolytic degradation and drug release kinetics in vitro were investigated by incubation in phosphate buffered saline solution. The results indicated that the icariin was released in a temporally controlled manner and the release kinetics could be governed by degradation of both chitosan and hydroxyapatite matrix. Finally the in vitro bioactivity assay revealed that the loaded icariin was biologically active as evidenced by stimulation of bone marrow derived stroma cell alkaline phosphatase activity and formation of mineralized nodules. This successful IC-CS/HA system offers a new delivery method of osteoinductive agents and a useful scaffold design for bone regeneration.

  19. Synthesis of fluorapatite–hydroxyapatite nanoparticles and toxicity investigations

    PubMed Central

    Montazeri, N; Jahandideh, R; Biazar, Esmaeil

    2011-01-01

    In this study, calcium phosphate nanoparticles with two phases, fluorapatite (FA; Ca10(PO4)6F2) and hydroxyapatite (HA; Ca10(PO4)6(OH)2), were prepared using the solgel method. Ethyl phosphate, hydrated calcium nitrate, and ammonium fluoride were used, respectively, as P, Ca, and F precursors with a Ca:P ratio of 1:72. Powders obtained from the sol-gel process were studied after they were dried at 80°C and heat treated at 550°C. The degree of crystallinity, particle and crystallite size, powder morphology, chemical structure, and phase analysis were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Zetasizer experiments. The results of XRD analysis and FTIR showed the presence of hydroxyapatite and fluorapatite phases. The sizes of the crystallites estimated from XRD patterns using the Scherrer equation and the crystallinity of the hydroxyapatite phase were about 20 nm and 70%, respectively. Transmission electron microscope and SEM images and Zetasizer experiments showed an average size of 100 nm. The in vitro behavior of powder was investigated with mouse fibroblast cells. The results of these experiments indicated that the powders were biocompatibile and would not cause toxic reactions. These compounds could be applied for hard-tissue engineering. PMID:21499417

  20. Electrophoretic deposition of double-layer HA/Al composite coating on NiTi.

    PubMed

    Karimi, Esmaeil; Khalil-Allafi, Jafar; Khalili, Vida

    2016-01-01

    In order to improve the bioactivity of NiTi alloys, which are being known as the suitable materials for biomedical applications, numerous NiTi disks were electrophoretically coated by hetero-coagulated hydroxyapatite/aluminum composite coatings in three main voltages from suspensions with different Al concentrations. In this paper, the amount of Ni ions release and bioactivity of prepared samples as well as bonding strength of the coating to substrate were investigated. The surface characterization of the coating by XRD, EDX, SEM, and FTIR showed that HA particles bonded by Al particles. It caused the formation of a free crack coating on NiTi disks. Moreover, the bonding strength of HA/Al coatings to NiTi substrate were improved by two times as compared to that of the pure HA coatings. Immersing of coated samples in SBF for 1 week showed that apatite formation ability was improved on HA/Al composite coating and Ni ions release from the surface of composite coating decreased. These results induce the appropriate bioactivity and biocompatibility of the deposited HA/Al composite coatings on NiTi disks. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Removal of heavy metal ions by biogenic hydroxyapatite: Morphology influence and mechanism study

    NASA Astrophysics Data System (ADS)

    Wang, Dandan; Guan, Xiaomei; Huang, Fangzhi; Li, Shikuo; Shen, Yuhua; Chen, Jun; Long, Haibo

    2016-08-01

    Based on the synthesis of hydroxyapatite (HA) with different morphologies, such as nanorod-like, flower-like and sphere-like assembled HA nanorods, a new strategy has been developed for the removal of heavy metal ions such as Pb2+, Cu2+, Mn2+, Zn2+. The dependence of removal efficiency on the morphology and the suspended concentration of trapping agent, the removal time and selectivity were evaluated and discussed. The experimental results proved that the removal capacity of flower-like assembled HA nanorods (NAFL-HA) was the best, and the maximum removal ratio for Pb2+ ion was 99.97%. The mechanism of Pb2+ removal was studied in detail, noting that some metal ions were completely incorporated into hydroxyapatitie to produce Pb-HA. It reveals that the metal ions capture by HA is mainly controlled by sample surface adsorption and co-precipitation, which are directly controlled by sample morphology.

  2. Organic aerogel microspheres

    DOEpatents

    Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

    1999-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  3. Biomimetic Hydroxyapatite Growth on Functionalized Surfaces of Ti-6Al-4V and Ti-Zr-Nb Alloys

    NASA Astrophysics Data System (ADS)

    Pylypchuk, Ie V.; Petranovskaya, A. L.; Gorbyk, P. P.; Korduban, A. M.; Markovsky, P. E.; Ivasishin, O. M.

    2015-08-01

    A biomimetic approach for coating titanium-containing alloys with hydroxyapatite (HA) is reported in the article. Two types of Ti-containing alloys were chosen as an object for coating: Ti-6Al-4V (recommended for orthopedic application) and a novel highly biocompatible Ti-Zr-Nb alloy, with good mechanical compatibility due to a modulus that is more close to that of human bones (E ≈ 50 GPa instead of 110 GPa in Ti-6Al-4V). Coating process was carried out in a 10×-concentrated simulated body fluid (SBF)—synthetic analog of human body plasma. The effect of oxidized and carboxylated alloy surface on formation of biomimetic hydroxyapatite has been studied. By XRD, we found influence of thermal conditions on HA crystal formation and size. SEM images and Fourier transform infrared confirmed that hydroxyapatite with different morphology, crystallinity, and Ca/P ratio formed on metallic surfaces. X-ray photoelectron spectroscopy showed that in the Ti-6AL-4V sample the observed Ca/P ratio reach 0.97, whereas in the Ti-Zr-Nb sample the observed Ca/P ratio reach 1.15.

  4. Synthesis, characterization and modelling of zinc and silicate co-substituted hydroxyapatite

    PubMed Central

    Friederichs, Robert J.; Chappell, Helen F.; Shepherd, David V.; Best, Serena M.

    2015-01-01

    Experimental chemistry and atomic modelling studies were performed here to investigate a novel ionic co-substitution in hydroxyapatite (HA). Zinc, silicate co-substituted HA (ZnSiHA) remained phase pure after heating to 1100°C with Zn and Si amounts of 0.6 wt% and 1.2 wt%, respectively. Unique lattice expansions in ZnSiHA, silicate Fourier transform infrared peaks and changes to the hydroxyl IR stretching region suggested Zn and silicate co-substitution in ZnSiHA. Zn and silicate insertion into HA was modelled using density functional theory (DFT). Different scenarios were considered where Zn substituted for different calcium sites or at a 2b site along the c-axis, which was suspected in singly substituted ZnHA. The most energetically favourable site in ZnSiHA was Zn positioned at a previously unreported interstitial site just off the c-axis near a silicate tetrahedron sitting on a phosphate site. A combination of experimental chemistry and DFT modelling provided insight into these complex co-substituted calcium phosphates that could find biomedical application as a synthetic bone mineral substitute. PMID:26040597

  5. Synthesis, characterization and modelling of zinc and silicate co-substituted hydroxyapatite.

    PubMed

    Friederichs, Robert J; Chappell, Helen F; Shepherd, David V; Best, Serena M

    2015-07-06

    Experimental chemistry and atomic modelling studies were performed here to investigate a novel ionic co-substitution in hydroxyapatite (HA). Zinc, silicate co-substituted HA (ZnSiHA) remained phase pure after heating to 1100 °C with Zn and Si amounts of 0.6 wt% and 1.2 wt%, respectively. Unique lattice expansions in ZnSiHA, silicate Fourier transform infrared peaks and changes to the hydroxyl IR stretching region suggested Zn and silicate co-substitution in ZnSiHA. Zn and silicate insertion into HA was modelled using density functional theory (DFT). Different scenarios were considered where Zn substituted for different calcium sites or at a 2b site along the c-axis, which was suspected in singly substituted ZnHA. The most energetically favourable site in ZnSiHA was Zn positioned at a previously unreported interstitial site just off the c-axis near a silicate tetrahedron sitting on a phosphate site. A combination of experimental chemistry and DFT modelling provided insight into these complex co-substituted calcium phosphates that could find biomedical application as a synthetic bone mineral substitute. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  6. Synergistic anticancer efficacy of Bendamustine Hydrochloride loaded bioactive Hydroxyapatite nanoparticles: In-vitro, ex-vivo and in-vivo evaluation.

    PubMed

    Thomas, Shindu C; Sharma, Harshita; Rawat, Purnima; Verma, Anita K; Leekha, Ankita; Kumar, Vijay; Tyagi, Aakriti; Gurjar, Bahadur S; Iqbal, Zeenat; Talegaonkar, Sushama

    2016-10-01

    The present work evaluates the synergistic anticancer efficacy of bioactive Hydroxyapatite (HA) nanoparticles (HA NPs) loaded with Bendamustine HCl. Hydroxyapatite is a material with an excellent biological compatibility, a well-known fact which was also supported by the results of the Hemolytic studies and a high IC50 value observed in the MTT assay. HA NPs were prepared by the chemical precipitation method and loaded with the drug via physical adsorption. In-vitro release study was performed, which confirmed the sustained release of the drug from the drug loaded HA NPs. MTT assay, Cell Uptake and FACS studies on JURKAT E6.1 cell line and in-vivo pharmacokinetic studies in Wistar rats revealed that the drug loaded HA NPs could be easily internalized by the cells and release drug in a sustained manner. The drug loaded HA NPs showed cytotoxicity similar to the drug solution at 1/10th of the drug content, which indicates a possible synergism between the activity of the anticancer drug and calcium ions derived from the carrier. An increase in intracellular Ca(2+) ions is reported to induce apoptosis in cells. Tumor regression study in Balb/c mice Ehrlich's ascites model presented a similar synergistic efficacy. The drug solution was able to decrease the tumor volume by half, while the drug loaded HA NPs reduced the tumor size by 6 times. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Synthesis of hydroxyapatite whiskers through dissolution reprecipitation process using EDTA

    NASA Astrophysics Data System (ADS)

    Seo, Dong Seok; Lee, Jong Kook

    2008-04-01

    Hydroxyapatite (HA) has been of interest in many industrial applications, such as ion exchange, catalysis and biomaterials. Chelating agents have often been used to prepare inorganic powders in the form of sphere, rod, whisker and fiber. In this study, HA whiskers were synthesized directly from typically shaped HA powders by refluxing at 80 and 100 °C for 24 h using ethylenediamine tetraacetic acid (EDTA). 3% or 6% of hydrogen peroxide (H 2O 2) was used to promote precipitation of HA crystals. The pH of the solution was adjusted at 7 or 9 by adding ammonia solution. The higher the H 2O 2 concentration, pH value and refluxing temperature, the longer and thinner whiskers were formed. The whiskers produced at 100 °C with 6% of H 2O 2 and pH 9 had the highest aspect ratio of about 50-60 (a length of 3 μm and a width of 0.05 μm).

  8. Enhancement of aptamer immobilization using egg shell-derived nano-sized spherical hydroxyapatite for thrombin detection in neuroclinic.

    PubMed

    Derkus, Burak; Arslan, Yavuz Emre; Emregul, Kaan C; Emregul, Emel

    2016-09-01

    In the present study, we describe the sonochemical isolation of nano-sized spherical hydroxyapatite (nHA) from egg shell and application towards thrombin aptasensing. In addition to the sonochemical method, two conventional methods present in literature were carried out to perform a comparative study. Various analysis methods including Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Energy-Dispersive Analysis of X-Rays (EDAX), and Thermal Gravimetric Analysis (TGA) have been applied for the characterization of nHA and its nanocomposite with marine-derived collagen isolated from Rhizostoma pulmo jellyfish. TEM micrographs revealed the sonochemically synthesized nHA nanoparticles to have a unique porous spherical shape with a diameter of approximately 60-80nm when compared to hydroxyapatite nanoparticles synthesized using the other two methods which had a typical needle shaped morphology. EDAX, XRD and FTIR results demonstrated that the obtained patterns belonged to hydroxyapatite. Electrochemical impedance spectroscopy (EIS) is the main analyzing technique of the developed thrombin aptasensor. The proposed aptasensor has a detection limit of 0.25nM thrombin. For clinical application of the developed aptasensor, thrombin levels in blood and cerebrospinal fluid (CSF) samples obtained from patients with Multiple Sclerosis, Myastenia Gravis, Epilepsy, Parkinson, polyneuropathy and healthy donors were analyzed using both the aptasensor and commercial ELISA kit. The results showed that the proposed system is a promising candidate for clinical analysis of thrombin. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Production of hollow aerogel microspheres

    DOEpatents

    Upadhye, Ravindra S.; Henning, Sten A.

    1993-01-01

    A method is described for making hollow aerogel microspheres of 800-1200 .mu. diameter and 100-300 .mu. wall thickness by forming hollow alcogel microspheres during the sol/gel process in a catalytic atmosphere and capturing them on a foam surface containing catalyst. Supercritical drying of the formed hollow alcogel microspheres yields hollow aerogel microspheres which are suitable for ICF targets.

  10. Nanocrystallized SrHA/SrHA SrTiO3/SrTiO3 TiO2 multilayer coatings formed by micro-arc oxidation for photocatalytic application

    NASA Astrophysics Data System (ADS)

    Han, Y.; Chen, D. H.; Zhang, L.

    2008-08-01

    Novel photocatalytic coatings containing strontium hydroxyapatite (SrHA), strontium titanate (SrTiO3), and TiO2 were formed by micro-arc oxidation (MAO) in an aqueous electrolyte containing strontium acetate and β-glycerophosphate disodium at 530 V for 0.1-5 min. The structure evolution of the coatings was investigated as a function of processing time, and the photocatalytic activity of the coatings was evaluated by measuring the decomposition rate of methyl orange under ultraviolet irradiation. During the MAO processing of the coatings, it was observed that some granules appeared in the electrolyte adjacent to the anode and they increased in amount as the processing time was prolonged. The obtained results show that the granules are amorphous and poorly crystallized SrHA with negative charges. The coating prepared for 5 min presents a microporous structure of SrHA/SrHA-SrTiO3/SrTiO3-TiO2 multilayers, in which the SrHA outermost layer and the SrHA-SrTiO3 intermediate layer are nanocrystallized. It is suggested that formation of the granules, electro-migration of the granules onto the pre-formed layer, and crystallization of the adhered granules are possible mechanisms for the formation of a SrHA/SrHA-SrTiO3/SrTiO3-TiO2 multilayer coating. This coating shows much higher photocatalytic decomposition efficiency relative to the MAO-formed TiO2 coating, and is expected to have an important photocatalytic application.

  11. Microsphere Insulation Panels

    NASA Technical Reports Server (NTRS)

    Mohling, R.; Allen, M.; Baumgartner, R.

    2006-01-01

    Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum.

  12. Development of gelatin-chitosan-hydroxyapatite based bioactive bone scaffold with controlled pore size and mechanical strength.

    PubMed

    Maji, Kanchan; Dasgupta, Sudip; Kundu, Biswanath; Bissoyi, Akalabya

    2015-01-01

    Hydroxyapatite-chitosan/gelatin (HA:Chi:Gel) nanocomposite scaffold has potential to serve as a template matrix to regenerate extra cellular matrix of human bone. Scaffolds with varying composition of hydroxyapatite, chitosan, and gelatin were prepared using lyophilization technique where glutaraldehyde (GTA) acted as a cross-linking agent for biopolymers. First, phase pure hydroxyapatite-chitosan nanocrystals were in situ synthesized by coprecipitation method using a solution of 2% acetic acid dissolved chitosan and aqueous solution of calcium nitrate tetrahydrate [Ca(NO3)2,4H2O] and diammonium hydrogen phosphate [(NH4)2H PO4]. Keeping solid loading constant at 30 wt% and changing the composition of the original slurry of gelatin, HA-chitosan allowed control of the pore size, its distribution, and mechanical properties of the scaffolds. Microstructural investigation by scanning electron microscopy revealed the formation of a well interconnected porous scaffold with a pore size in the range of 35-150 μm. The HA granules were uniformly dispersed in the gelatin-chitosan network. An optimal composition in terms of pore size and mechanical properties was obtained from the scaffold with an HA:Chi:Gel ratio of 21:49:30. The composite scaffold having 70% porosity with pore size distribution of 35-150 μm exhibited a compressive strength of 3.3-3.5 MPa, which is within the range of that exhibited by cancellous bone. The bioactivity of the scaffold was evaluated after conducting mesenchymal stem cell (MSC) - materials interaction and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay using MSCs. The scaffold found to be conducive to MSC's adhesion as evident from lamellipodia, filopodia extensions from cell cytoskeleton, proliferation, and differentiation up to 14 days of cell culture.

  13. Ridge Preservation After Maxillary Third Molar Extraction Using 30% Porosity PLGA/HA/β-TCP Scaffolds With and Without Simvastatin: A Pilot Randomized Controlled Clinical Trial.

    PubMed

    Noronha Oliveira, Miguel; Rau, Levy Hermes; Marodin, Aline; Corrêa, Márcio; Corrêa, Letícia Ruhland; Aragones, Aguedo; Magini, Ricardo de Souza

    2017-12-01

    To evaluate clinically and radiographically, in humans, the healing of maxillary third molars postextraction sockets after application of different ridge preservation techniques 3 months after tooth extraction. Twenty-six sockets (13 patients) were randomly assigned to 4 treatment modalities: deproteinized bovine bone mineral with 10% collagen (DBBM-C), poly(D,L-lactide-co-glycolide) with hydroxyapatite/β-TCP scaffold (PLGA/HA), PLGA/HA/β-TCP with 2.0% simvastatin scaffold (PLGA/HA/S), and spontaneous healing (control). Clinical complications were assessed, and cone-beam computed tomographies were taken in 5 patients 3 months after surgeries. For statistical purposes, the Fisher exact test was used (P < 0.05). After 3 months, 6 of 9 grafts from the PLGA/HA group were lost (P < 0.05). PLGA/HA/S' loss was only 2 of 8 (P > 0.05), but no loss was observed in the DBBM-C group. Pain was present in 3 of 8 sites that lost the graft (37.5%) (P > 0.05) and infection in 1 of 8 (12.5%) (P > 0.05), with these only occurring in the PLGA/HA group. Poly (D, L-lactide-co-glycolide) with hydroxyapatite/β-TCP (PLGA/HA/β-TCP) scaffolds, with and without simvastatin, failed to obtain the initial expected results and presented more complications. Scaffolds with simvastatin showed to be superior, with less clinical complications than scaffolds without simvastatin.

  14. Organic aerogel microspheres

    DOEpatents

    Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

    1999-06-01

    Organic aerogel microspheres are disclosed which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonstick gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  15. Strontium-doped hydroxyapatite polysaccharide materials effect on ectopic bone formation

    PubMed Central

    Aid-Launais, R.; Sagardoy, T.; Siadous, R.; Bareille, R.; Rey, S.; Pechev, S.; Etienne, L.; Kalisky, J.; de Mones, E.; Letourneur, D.; Amedee Vilamitjana, J.

    2017-01-01

    Previous studies performed using polysaccharide-based matrices supplemented with hydroxyapatite (HA) particles showed their ability to form in subcutaneous and intramuscular sites a mineralized and osteoid tissue. Our objectives are to optimize the HA content in the matrix and to test the combination of HA with strontium (Sr-HA) to increase the matrix bioactivity. First, non-doped Sr-HA powders were combined to the matrix at three different ratios and were implanted subcutaneously for 2 and 4 weeks. Interestingly, matrices showed radiolucent properties before implantation. Quantitative analysis of micro-CT data evidenced a significant increase of mineralized tissue formed ectopically with time of implantation and allowed us to select the best ratio of HA to polysaccharides of 30% (w/w). Then, two Sr-substitution of 8% and 50% were incorporated in the HA powders (8Sr-HA and 50Sr-HA). Both Sr-HA were chemically characterized and dispersed in matrices. In vitro studies performed with human mesenchymal stem cells (MSCs) demonstrated the absence of cytotoxicity of the Sr-doped matrices whatever the amount of incorporated Sr. They also supported osteoblastic differentiation and activated the expression of one late osteoblastic marker involved in the mineralization process i.e. osteopontin. In vivo, subcutaneous implantation of these Sr-doped matrices induced osteoid tissue and blood vessels formation. PMID:28910401

  16. Comparative NEXAFS study of the selected icefish hard tissues and hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Petrova, O. V.; Nekipelov, S. V.; Sivkov, D. V.; Mingaleva, A. E.; Nikolaev, A.; Frank-Kamenetskaya, O. V.; Bazhenov, V. V.; Vyalikh, D. V.; Molodtsov, S. L.; Sivkov, V. N.; Ehrlich, H.

    2017-11-01

    The structure of native Champsocephalus gunnari icefish otoliths, scales, teeth, bones and pristine hydroxyapatite (HA) were examined using Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. NEXAFS Cls-absorption spectra of the selected icefish hard tissues indicate that otoliths contain anion [CO3]2-. NEXAFS P2p-spectra clearly indicate the absence of phosphorus atoms only within otoliths and scales samples. However, the icefish teeth and bones P2p-spectra demonstrate identical spectral feature typical for the HA. NEXAFS Ca2p-spectra of the icefish hard tissues studied also shows features, which are in good correspondence with HA spectra. Interestingly, there is a red shift ≈ 0.1 eV of the 2p1/2,3/2 → 3d transition energies in NEXAFS Ca2p-spectra of teethes and bones of the C. gunnari in comparison to HA.

  17. Modulating protein adsorption onto hydroxyapatite particles using different amino acid treatments

    PubMed Central

    Lee, Wing-Hin; Loo, Ching-Yee; Van, Kim Linh; Zavgorodniy, Alexander V.; Rohanizadeh, Ramin

    2012-01-01

    Hydroxyapatite (HA) is a material of choice for bone grafts owing to its chemical and structural similarities to the mineral phase of hard tissues. The combination of osteogenic proteins with HA materials that carry and deliver the proteins to the bone-defective areas will accelerate bone regeneration. The study investigated the treatment of HA particles with different amino acids such as serine (Ser), asparagine (Asn), aspartic acid (Asp) and arginine (Arg) to enhance the adsorption ability of HA carrier for delivering therapeutic proteins to the body. The crystallinity of HA reduced when amino acids were added during HA preparation. Depending on the types of amino acid, the specific surface area of the amino acid-functionalized HA particles varied from 105 to 149 m2 g–1. Bovine serum albumin (BSA) and lysozyme were used as model proteins for adsorption study. The protein adsorption onto the surface of amino acid-functionalized HA depended on the polarities of HA particles, whereby, compared with lysozyme, BSA demonstrated higher affinity towards positively charged Arg-HA. Alternatively, the binding affinity of lysozyme onto the negatively charged Asp-HA was higher when compared with BSA. The BSA and lysozyme adsorptions onto the amino acid-functionalized HA fitted better into the Freundlich than Langmuir model. The amino acid-functionalized HA particles that had higher protein adsorption demonstrated a lower protein-release rate. PMID:21957116

  18. Comparison of new bone formation, implant integration, and biocompatibility between RGD-hydroxyapatite and pure hydroxyapatite coating for cementless joint prostheses--an experimental study in rabbits.

    PubMed

    Bitschnau, Achim; Alt, Volker; Böhner, Felicitas; Heerich, Katharina Elisabeth; Margesin, Erika; Hartmann, Sonja; Sewing, Andreas; Meyer, Christof; Wenisch, Sabine; Schnettler, Reinhard

    2009-01-01

    This is the first work to report on additional Arginin-Glycin-Aspartat (RGD) coating on precoated hydroxyapatite (HA) surfaces regarding new bone formation, implant bone contact, and biocompatibility compared to pure HA coating and uncoated stainless K-wires. There were 39 rabbits in total with 6 animals for the RGD-HA and HA group for the 4 week time period and 9 animals for each of the 3 implant groups for the 12 week observation. A 2.0 K-wire either with RGD-HA or with pure HA coating or uncoated was placed into the intramedullary canal of the tibia. After 4 and 12 weeks, the tibiae were harvested and three different areas of the tibia were assessed for quantitative and qualitative histology for new bone formation, direct implant bone contact, and formation of multinucleated giant cells. Both RGD-HA and pure HA coating showed statistically higher new bone formation and implant bone contact after 12 weeks than the uncoated K-wire. There were no significant differences between the RGD-HA and the pure HA coating in new bone formation and direct implant bone contact after 4 and 12 weeks. The number of multinucleated giant did not differ significantly between the RGD-HA and HA group after both time points. Overall, no significant effects of an additional RGD coating on HA surfaces were detected in this model after 12 weeks. (c) 2008 Wiley Periodicals, Inc.

  19. On the use of superparamagnetic hydroxyapatite nanoparticles as an agent for magnetic and nuclear in vivo imaging.

    PubMed

    Adamiano, Alessio; Iafisco, Michele; Sandri, Monica; Basini, Martina; Arosio, Paolo; Canu, Tamara; Sitia, Giovanni; Esposito, Antonio; Iannotti, Vincenzo; Ausanio, Giovanni; Fragogeorgi, Eirini; Rouchota, Maritina; Loudos, George; Lascialfari, Alessandro; Tampieri, Anna

    2018-06-01

    The identification of alternative biocompatible magnetic NPs for advanced clinical application is becoming an important need due to raising concerns about iron accumulation in soft issues associated to the administration of superparamagnetic iron oxide nanoparticles (NPs). Here, we report on the performance of previously synthetized iron-doped hydroxyapatite (FeHA) NPs as contrast agent for magnetic resonance imaging (MRI). The MRI contrast abilities of FeHA and Endorem® (dextran coated iron oxide NPs) were assessed by 1 H nuclear magnetic resonance relaxometry and their performance in healthy mice was monitored by a 7 Tesla scanner. FeHA applied a higher contrast enhancement, and had a longer endurance in the liver with respect to Endorem® at iron equality. Additionally, a proof of concept of FeHA use as scintigraphy imaging agent for positron emission tomography (PET) and single photon emission computed tomography (SPECT) was given labeling FeHA with 99m Tc-MDP by a straightforward surface functionalization process. Scintigraphy/x-ray fused imaging and ex vivo studies confirmed its dominant accumulation in the liver, and secondarily in other organs of the mononuclear phagocyte system. FeHA efficiency as MRI-T 2 and PET-SPECT imaging agent combined to its already reported intrinsic biocompatibility qualifies it as a promising material for innovative nanomedical applications. The ability of iron-doped hydroxyapatite nanoaprticles (FeHA) to work in vivo as imaging agents for magnetic resonance (MR) and nuclear imaging is demonstrated. FeHA applied an higher MR contrast in the liver, spleen and kidneys of mice with respect to Endorem®. The successful radiolabeling of FeHA allowed for scintigraphy/X-ray and ex vivo biodistribution studies, confirming MR results and envisioning FeHA application for dual-imaging. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Powder Metallurgical Synthesis of Biodegradable Mg-Hydroxyapatite Composites for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Stüpp, Cesar Augusto; Szakács, Gábor; Mendis, Chamini Lakshi; Gensch, Felix; Müller, Sören; Feyerabend, Frank; Hotza, Dachamir; Fredel, Marcio Celso; Hort, Norbert

    Magnesium alloys with acceptable or even controllable corrosion rates, where mechanical properties are not significantly modified or worsened, have been increasingly investigated in the last decade for use as biomaterials. This work shows an approach with a magnesium metal matrix composite (Mg-MMC), composed of ZK60 as base material and hydroxyapatite (HA) particles. The composite was produced by mechanical alloying followed by hot extrusion, as HA in contact with molten magnesium releases toxic gases such as phosphine (PH3). This work will present the influence of different amounts of HA on corrosion behaviour and mechanical properties of the investigated composites. Compared to the ZK60 alloy, corrosion is expected to be delayed, without localized corrosion. The mechanical properties are not expected to be compromised with such composite during tissue's healing period.

  1. Zinc-substituted hydroxyapatite: a biomaterial with enhanced bioactivity and antibacterial properties.

    PubMed

    Thian, E S; Konishi, T; Kawanobe, Y; Lim, P N; Choong, C; Ho, B; Aizawa, M

    2013-02-01

    Hydroxyapatite (HA) is a synthetic biomaterial and has been found to promote new bone formation when implanted in a bone defect site. However, its use is often limited due to its slow osteointegration rate and low antibacterial activity, particularly where HA has to be used for long term biomedical applications. This work will describe the synthesis and detailed characterization of zinc-substituted HA (ZnHA) as an alternative biomaterial to HA. ZnHA containing 1.6 wt% Zn was synthesized via a co-precipitation reaction between calcium hydroxide, orthophosphoric acid and zinc nitrate hexahydrate. Single-phase ZnHA particles with a rod-like morphology measuring ~50 nm in length and ~15 nm in width, were obtained and characterized using transmission electron microscopy and X-ray diffraction. The substitution of Zn into HA resulted in a decrease in both the a- and c-axes of the unit cell parameters, thereby causing the HA crystal structure to alter. In vitro cell culture work showed that ZnHA possessed enhanced bioactivity since an increase in the growth of human adipose-derived mesenchymal stem cells along with the bone cell differentiation markers, were observed. In addition, antibacterial work demonstrated that ZnHA exhibited antimicrobial capability since there was a significant decrease in the number of viable Staphylococcus aureus bacteria after in contact with ZnHA.

  2. Mechanical properties of nanodiamond-reinforced hydroxyapatite composite coatings deposited by suspension plasma spraying

    NASA Astrophysics Data System (ADS)

    Chen, Xiuyong; Zhang, Botao; Gong, Yongfeng; Zhou, Ping; Li, Hua

    2018-05-01

    Hydroxyapatite (HA) coatings suffer from poor mechanical properties, which can be enhanced via incorporation of secondary bioinert reinforcement material. Nanodiamond (ND) possesses excellent mechanical properties to play the role as reinforcement for improving the mechanical properties of brittle HA bioceramic coatings. The major persistent challenge yet is the development of proper deposition techniques for fabricating the ND reinforced HA coatings. In this study, we present a novel deposition approach by plasma spraying the mixtures of ND suspension and micron-sized HA powder feedstock. The effect of ND reinforcement on the microstructure and the mechanical properties of the coatings such as hardness, adhesive strength and friction coefficient were examined. The results showed that the ND-reinforced HA coatings display lower porosity, fewer unmelted particles and uniform microstructure, in turn leading to significantly enhanced mechanical properties. The study presented a promising approach to fabricate ND-reinforced HA composite coatings on metal-based medical implants for potential clinical application.

  3. Optical properties of hydroxyapatite obtained by mechanical alloying

    NASA Astrophysics Data System (ADS)

    Silva, C. C.; Thomazini, D.; Pinheiro, A. G.; Lanciotti, F.; Sasaki, J. M.; Góes, J. C.; Sombra, A. S. B.

    2002-09-01

    Calcium phosphate based bioceramics, mainly in the form of hydroxyapatite (HA), have been in use in medicine and dentistry for the last 20 years. Applications include coatings of orthopaedic and dental implants, alveolar ridge augmentation, maxillofacial surgery, otolaryngology, and scaffolds for bone growth and as powders in total hip and knee surgery. These materials exhibit several problems of handling and fabrication, which can be overcome by mixing with a suitable binder. In this paper, mechanical alloying has been used successfully to produce nanocrystalline powders of HA using five different experimental procedures. The milled HA were studied by X-ray powder diffraction, infrared and Raman scattering spectroscopy. For four different procedures, HA was obtained after a couple of hours of milling (on an average, 20 h of milling depending on the reaction procedure). The XRD patterns indicate that the grain size is within the range of 29-103 nm. This milling process, used to produce HA, presents the advantage that melting is not necessary and the powder obtained is nanocrystalline with extraordinary mechanical properties. The material can be compacted and transformed in solid ceramic samples. The high efficiency of the process opens a way to produce commercial amount of nanocrystalline HA. Due to the nanocrystalline character of this powder, their mechanical properties have changed and for this reason a pressure of 1 GPa is enough to shape the sample into any geometry.

  4. Synthesis, structure and temperature dependent luminescence of Eu3+ doped hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Luo, Xiaobing; Luo, Xiaoxia; Wang, Hongwei; Deng, Yue; Yang, Peixin; Tian, Yili

    2018-01-01

    A series of Eu3+ substituted hydroxyapatite (HA) were prepared by co-precipitation reactions. The phase, fluorescence and temperature dependent luminescence of the phosphors were investigated by X-ray diffraction (XRD) and photoluminescence (PL). It is found that the doped Eu3+ ions have entered the hexagonal lattice with no obvious secondary phase were detected by XRD. The 5D0 → 7F0 transition was clearly split into two even at room temperature. The predominate 573 nm peak illustrates Eu3+ ions occupy more Ca(II) sites. The temperature dependent luminescent results show HA:xEu might be applied as one potential optical thermometry material.

  5. The influence of silanisation on the mechanical and degradation behaviour of PLGA/HA composites.

    PubMed

    Naik, Ashutosh; Best, Serena M; Cameron, Ruth E

    2015-03-01

    This study investigates the influence of silanisation on the mechanical and degradation behaviour of PLGA/HA composites. Three different silanes (mercaptopropyl trimethoxy silane (MPTMS), aminopropyl trimethoxy silane (APTMS) and aminopropyltriethoxy silane (APTES)) were applied to HA substrates in order to study the effect of head group (which binds to the polymer) and tail group (which binds to the surface hydroxyl groups in HA). A composite of hydroxyapatite (HA) and poly(d,l lactide-co-glycolide (50:50)) (PLGA) was investigated. The influence of concentration, the reaction time, drying temperature and substrate surface on silanisation was examined. TGA was used to detect the degree of silanisation. HA with MPTMS (1wt.% MPTMS with reaction time of 1h) was used as filler in PLGA-30wt.% HA composites for an in-vitro degradation study carried out in PBS. In addition, the mechanical properties of the composites were studied. Silanisation affects the properties of the composite by improving the bonding at the interface and hence it was found to influence the plastic mechanical properties rather than the elastic mechanical properties or the degradation profile of the composite. Copyright © 2014. Published by Elsevier B.V.

  6. In vitro and in vivo investigation of bisphosphonate-loaded hydroxyapatite particles for peri-implant bone augmentation.

    PubMed

    Kettenberger, Ulrike; Luginbuehl, Vera; Procter, Philip; Pioletti, Dominique P

    2017-07-01

    Locally applied bisphosphonates, such as zoledronate, have been shown in several studies to inhibit peri-implant bone resorption and recently to enhance peri-implant bone formation. Studies have also demonstrated positive effects of hydroxyapatite (HA) particles on peri-implant bone regeneration and an enhancement of the anti-resorptive effect of bisphosphonates in the presence of calcium. In the present study, both hydroxyapatite nanoparticles (nHA) and zoledronate were combined to achieve a strong reinforcing effect on peri-implant bone. The nHA-zoledronate combination was first investigated in vitro with a pre-osteoclastic cell assay (RAW 264.7) and then in vivo in a rat model of postmenopausal osteoporosis. The in vitro study confirmed that the inhibitory effect of zoledronate on murine osteoclast precursor cells was enhanced by loading the drug on nHA. For the in vivo investigation, either zoledronate-loaded or pure nHA were integrated in hyaluronic acid hydrogel. The gels were injected in screw holes that had been predrilled in rat femoral condyles before the insertion of miniature screws. Micro-CT-based dynamic histomorphometry and histology revealed an unexpected rapid mineralization of the hydrogel in vivo through formation of granules, which served as scaffold for new bone formation. The delivery of zoledronate-loaded nHA further inhibited a degradation of the mineralized hydrogel as well as a resorption of the peri-implant bone as effectively as unbound zoledronate. Hyaluronic acid with zoledronate-loaded nHA, thanks to its dual effect on inducing a rapid mineralization and preventing resorption, is a promising versatile material for bone repair and augmentation. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  7. Investigation of chronic toxicity of hydroxyapatite nanoparticles administered orally for one year in wistar rats.

    PubMed

    Remya, N S; Syama, S; Sabareeswaran, A; Mohanan, P V

    2017-07-01

    Although the toxicity/biocompatibility of hydroxyapatite nanoparticles (nano HA), a prospective nano biomaterial is extensively studied, its interaction on biological systems following chronic exposure is less exploited. In the present study, Wistar rats were given various concentrations of nano HA in the diet to determine the chronic toxicity and potential carcinogenicity. Altogether 140 rats were used for the study under various administration dosages along with control. The animals were sacrificed after 12months of controlled continuous dosing. All in-life parameters, including body weight, food consumption, clinical observations, survival, biochemical and hematology, were unaffected by the chronic exposure of nano HA orally. Similarly, gross and histopathological evaluation was also unchanged following exposure to nano HA. No evidence of nano HA-related lesions or Nano HA-induced neoplasia was suggested in this rodent bioassay study. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites

    PubMed Central

    Li, Feng; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao

    2018-01-01

    Biomaterial composites made of titanium and hydroxyapatite (HA) powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD), back scattered electron imaging (BSE), scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS), electron probe microanalyzer (EPMA), and transmission electron microscope (TEM). The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca3(PO4)2, TixPy, and Ti3O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed. PMID:29659504

  9. Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites.

    PubMed

    Li, Feng; Jiang, Xiaosong; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao

    2018-04-16

    Biomaterial composites made of titanium and hydroxyapatite (HA) powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD), back scattered electron imaging (BSE), scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS), electron probe microanalyzer (EPMA), and transmission electron microscope (TEM). The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca₃(PO₄)₂, Ti x P y , and Ti₃O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed.

  10. Osteogenic Responses to Zirconia with Hydroxyapatite Coating by Aerosol Deposition

    PubMed Central

    Cho, Y.; Hong, J.; Ryoo, H.; Kim, D.; Park, J.

    2015-01-01

    Previously, we found that osteogenic responses to zirconia co-doped with niobium oxide (Nb2O5) or tantalum oxide (Ta2O5) are comparable with responses to titanium, which is widely used as a dental implant material. The present study aimed to evaluate the in vitro osteogenic potential of hydroxyapatite (HA)-coated zirconia by an aerosol deposition method for improved osseointegration. Surface analysis by scanning electron microscopy and x-ray diffraction proved that a thin as-deposited HA film on zirconia showed a shallow, regular, crater-like surface. Deposition of dense and uniform HA films was measured by SEM, and the contact angle test demonstrated improved wettability of the HA-coated surface. Confocal laser scanning microscopy indicated that MC3T3-E1 pre-osteoblast attachment did not differ notably between the titanium and zirconia surfaces; however, cells on the HA-coated zirconia exhibited a lower proliferation than those on the uncoated zirconia late in the culture. Nevertheless, ALP, alizarin red S staining, and bone marker gene expression analysis indicated good osteogenic responses on HA-coated zirconia. Our results suggest that HA-coating by aerosol deposition improves the quality of surface modification and is favorable to osteogenesis. PMID:25586588

  11. Beneficial effects of hydroxyapatite on enamel subjected to 30% hydrogen peroxide.

    PubMed

    Jiang, Tao; Ma, Xiao; Wang, Zhejun; Tong, Hua; Hu, Jiming; Wang, Yining

    2008-11-01

    To evaluate the effect of combination of hydroxyapatite (HA) and hydrogen peroxide (HP) on color, microhardness and morphology of human tooth enamel. Forty-eight human dental blocks were obtained from 12 pairs of premolars and were randomly divided into four groups. Group DW was treated with distilled water, group HP with 30% HP, group HA+DW with HA mixed with distilled water and group HA+HP with HA mixed with 30% HP. Baseline and final color measurements and microhardness test were carried out before and after bleaching experiments. Two specimens from each group were selected for morphological investigation after final tests. The DeltaE of group HP and HA+HP were significantly higher than those of group DW (p=0.000 and p=0.000) and group HA+DW (p=0.000 and p=0.000). The percentage microhardness loss of group HA+HP was significantly lower than that of group HP (p=0.047), but significantly higher than those of group DW (p=0.000) and group HA+DW (p=0.000). The obvious variation of morphology was only observed on enamel surfaces in group HP. This study suggested that combination of HA and HP was effective in tooth whitening. HA could significantly reduce the microhardness loss of enamel caused by 30% HP and keep enamel surface morphology almost unchanged.

  12. HVOF-Sprayed Nano TiO2-HA Coatings Exhibiting Enhanced Biocompatibility

    NASA Astrophysics Data System (ADS)

    Lima, R. S.; Dimitrievska, S.; Bureau, M. N.; Marple, B. R.; Petit, A.; Mwale, F.; Antoniou, J.

    2010-01-01

    Biomedical thermal spray coatings produced via high-velocity oxy-fuel (HVOF) from nanostructured titania (n-TiO2) and 10 wt.% hydroxyapatite (HA) (n-TiO2-10wt.%HA) powders have been engineered as possible future alternatives to HA coatings deposited via air plasma spray (APS). This approach was chosen due to (i) the stability of TiO2 in the human body (i.e., no dissolution) and (ii) bond strength values on Ti-6Al-4V substrates more than two times higher than those of APS HA coatings. To explore the bioperformance of these novel materials and coatings, human mesenchymal stem cells (hMSCs) were cultured from 1 to 21 days on the surface of HVOF-sprayed n-TiO2 and n-TiO2-10 wt.%HA coatings. APS HA coatings and uncoated Ti-6Al-4V substrates were employed as controls. The profiles of the hMSCs were evaluated for (i) cellular proliferation, (ii) biochemical analysis of alkaline phosphatase (ALP) activity, (iii) cytoskeleton organization (fluorescent/confocal microscopy), and (iv) cell/substrate interaction via scanning electron microscopy (SEM). The biochemical analysis indicated that the hMSCs cultured on n-TiO2-10 wt.%HA coatings exhibited superior levels of bioactivity than hMSCs cultured on APS HA and pure n-TiO2 coatings. The cytoskeleton organization demonstrated a higher degree of cellular proliferation on the HVOF-sprayed n-TiO2-10wt.%HA coatings when compared to the control coatings. These results are considered promising for engineering improved performance in the next generation of thermally sprayed biomedical coatings.

  13. The role of amino acids in hydroxyapatite mineralization

    PubMed Central

    2016-01-01

    Polar and charged amino acids (AAs) are heavily expressed in non-collagenous proteins (NCPs), and are involved in hydroxyapatite (HA) mineralization in bone. Here, we review what is known on the effect of single AAs on HA precipitation. Negatively charged AAs, such as aspartic acid, glutamic acid (Glu) and phosphoserine are largely expressed in NCPs and play a critical role in controlling HA nucleation and growth. Positively charged ones such as arginine (Arg) or lysine (Lys) are heavily involved in HA nucleation within extracellular matrix proteins such as collagen. Glu, Arg and Lys intake can also increase bone mineral density by stimulating growth hormone production. In vitro studies suggest that the role of AAs in controlling HA precipitation is affected by their mobility. While dissolved AAs are able to inhibit HA precipitation and growth by chelating Ca2+ and PO43− ions or binding to nuclei of calcium phosphate and preventing their further growth, AAs bound to surfaces can promote HA precipitation by attracting Ca2+ and PO43− ions and increasing the local supersaturation. Overall, the effect of AAs on HA precipitation is worth being investigated more, especially under conditions closer to the physiological ones, where the presence of other factors such as collagen, mineralization inhibitors, and cells heavily influences HA precipitation. A deeper understanding of the role of AAs in HA mineralization will increase our fundamental knowledge related to bone formation, and could lead to new therapies to improve bone regeneration in damaged tissues or cure pathological diseases caused by excessive mineralization in tissues such as cartilage, blood vessels and cardiac valves. PMID:27707904

  14. Physical Properties and Cellular Responses to Crosslinkable Poly(Propylene Fumarate)/Hydroxyapatite Nanocomposites

    PubMed Central

    Lee, Kee-Won; Wang, Shanfeng; Yaszemski, Michael J.; Lu, Lichun

    2008-01-01

    A series of crosslinkable nanocomposites has been developed using hydroxyapatite (HA) nanoparticles and poly(propylene fumarate) (PPF). PPF/HA nanocomposites with four different weight fractions of HA nanoparticles have been characterized in terms of thermal and mechanical properties. To assess surface chemistry of crosslinked PPF/HA nanocomposites, their hydrophilicity and capability of adsorbing proteins have been determined using static contact angle measurement and MicroBCA protein assay kit after incubation with 10% fetal bovine serum (FBS), respectively. In vitro cell studies have been performed using MC3T3-E1 mouse pre-osteoblast cells to investigate the ability of PPF/HA nanocomposites to support cell attachment, spreading, and proliferation after 1, 4, and 7 days. By adding HA nanoparticles to PPF, the mechanical properties of crosslinked PPF/HA nanocomposites have not been increased due to the initially high modulus of crosslinked PPF. However, hydrophilicity and serum protein adsorption on the surface of nanocomposites have been significantly increased, resulting in enhanced cell attachment, spreading, and proliferation after 4 days of cell seeding. These results indicate that crosslinkable PPF/HA nanocomposites are useful for hard tissue replacement because of excellent mechanical strength and osteoconductivity. PMID:18403013

  15. Microleakage under orthodontic bands cemented with nano-hydroxyapatite-modified glass ionomer.

    PubMed

    Enan, Enas T; Hammad, Shaza M

    2013-11-01

    To estimate the in vivo effect of nano-hydroxyapatite (HA) modification of banding glass-ionomer cement on microleakage under orthodontic bands. Eighty noncarious premolars scheduled for extraction in 20 orthodontic patients were randomly divided into four groups. Grouping was based on the ratio of nano-HA (0%, 5%, 10%, 15% by weight) added to the luting glass-ionomer cement (GIC) Ketac-Cem, which was used for cementation of prefabricated micro-etched orthodontic bands. Dye penetration method was used for microleakage evaluation at the cement-band and cement-enamel interfaces. Statistical evaluation was performed with a Kruskal-Wallis test and a Mann-Whitney U-test, and a Bonferroni-adjusted significance level was calculated. Bands cemented with conventional GIC showed the highest microleakage scores in comparison to those cemented with nano-HA-modified GIC. No significant difference was found between teeth banded with 10% and 15% modified GIC. Modification of the banding GIC with 15% nano-HA revealed a positive effect on reducing microleakage around orthodontic bands.

  16. The influence of Ca/P ratio on the properties of hydroxyapatite bioceramics

    NASA Astrophysics Data System (ADS)

    Ramesh, S.; Tan, C. Y.; Hamdi, M.; Sopyan, I.; Teng, W. D.

    2007-07-01

    The paper reports on the effect of Ca/P ratio (1.57, 1.67 and 1.87) on the densification behaviour of nanocrystalline hydroxyapatite (HA) prepared by a chemical precipitation method. Green compacts were prepared and sintered at temperatures ranging from 1000°C to 1350°C. The sintered samples were characterized to determine the HA phase stability, bulk density, hardness, fracture toughness and Young's modulus. XRD analysis revealed that the phase stability was not disrupted throughout the sintering regime employed for HA having Ca/P ratio of 1.57 and 1.67. However, secondary phases were observed for HA having a Ca/P ratio of 1.87 when sintered at high temperatures. In general, regardless of Ca/P ratio, the HA bodies achieved > 95% relative density when sintered at 1100°C-1250°C. The results indicated that the stoichiometric HA (Ca/P ratio = 1.67) exhibited the overall best properties, with the highest hardness of 7.23 GPa and fracture toughness of 1.28 MPam1/2 being attained when sintered at 1000°C-1050°C.

  17. Fabrication of DNA/Hydroxyapatite nanocomposites by simulated body fluid for gene delivery

    NASA Astrophysics Data System (ADS)

    Takeshita, Takayuki; Okamoto, Masami

    2015-05-01

    The hydroxyapatite (HA) formation on the surface of DNA molecules in simulated body fluid (SBF) was examined. The osteoconductivity is estimated using SBF having ion concentrations approximately equal to those of human blood plasma. After immersion for 4 weeks in SBF at 36.5 °C, the HA crystallites possessing 1-14 micrometer in diameter grew on the surface of DNA molecules. The leaf flake-like and spherical shapes morphologies were observed through scanning electron microscopy analysis. Original peaks of both of DNA and HA were characterized by fourier transform infrared spectroscopy. The Ca/P ratio (1.1-1.5) in HA was estimated by energy dispersive X-ray analysis. After biomineralization, the calculated weight ratio of DNA/HA was 18/82 by thermogravimetry/differential thermal analysis. The molecular orbital computer simulation has been used to probe the interaction of DNA with two charge-balancing ions, CaOH+ and C a H2P O4+ . The adsorption enthalpy of the two ions on DNA having negative value was the evidence for the interface in mineralization of HA in SBF.

  18. Mechanochemical Synthesis of Hydroxyapatite and Its Modifications: Composition, Structure, and Properties

    NASA Astrophysics Data System (ADS)

    Chaikina, M. V.; Bulina, N. V.; Ishchenko, A. V.; Prosanov, I. Yu.

    2014-02-01

    The mechanochemical method is used to synthesize samples of hydroxyapatite (HA) with substitution of the phosphate ion by silicate and zirconate ions, and substitution of calcium ions by copper ions. In the process of mechanochemical synthesis, carbonate ions and water molecules are incorporated into the structure of HA due to interaction of components of the reaction mixture with air. Intrusion of carbonate into the structure of HA is a competing process with modification of apatite by silicate and zirconate anions; therefore, the composition of the product during synthesis differs from the prescribed one. After annealing of the samples, the composition of the anion-modified HA can be described by the formula Са10(РО4)6- х (АО4) х (ОН)2- х , where (АО4)4- is the modifying anion. Substitution of calcium by copper ions localized at the Са1 position has been detected. Silver ions are not incorporated into the structure of HA, but are distributed in the apatite matrix in the form of nanocrystals of metallic silver.

  19. Diversity of multinucleated giant cells by microstructures of hydroxyapatite and plasma components in extraskeletal implantation model.

    PubMed

    Morishita, Kota; Tatsukawa, Eri; Shibata, Yasuaki; Suehiro, Fumio; Kamitakahara, Masanobu; Yokoi, Taishi; Ioku, Koji; Umeda, Masahiro; Nishimura, Masahiro; Ikeda, Tohru

    2016-07-15

    Foreign body giant cells (FBGCs) and osteoclasts are multinucleated giant cells (MNGCs), both of which are formed by the fusion of macrophage-derived mononuclear cells. Osteoclasts are distinct from FBGCs due to their bone resorption ability; however, not only morphological, but also functional similarities may exist between these cells. The characterization and diversity of FBGCs that appear in an in vivo foreign body reaction currently remain incomplete. In the present study, we investigated an in vivo foreign body reaction using an extraskeletal implantation model of hydroxyapatite (HA) with different microstructures. The implantation of HA granules in rat subcutaneous tissue induced a foreign body reaction that was accompanied by various MNGCs. HA granules composed of rod-shaped particles predominantly induced cathepsin K (CTSK)-positive FBGCs, whereas HA granules composed of globular-shaped particles predominantly induced CTSK-negative FBGCs. Plasma, which was used as the binder of ceramic granules, stimulated the induction of CTSK-positive FBGCs more strongly than purified fibrin. Furthermore, the implantation of HA composed of rod-shaped particles with plasma induced tartrate-resistant acid phosphatase (TRAP)-positive MNGCs in contrast to HA composed of globular-shaped particles with purified fibrin, which predominantly induced CTSK-negative and TRAP-negative typical FBGCs. These results suggest that CTSK-positive, TRAP-positive, and CTSK- and TRAP-negative MNGCs are induced in this subcutaneous implantation model in a manner that is dependent on the microstructure of HA and presence or absence of plasma. We attempted to elucidate the mechanisms responsible for the foreign body reaction induced by the implantation of hydroxyapatite granules with different microstructures in rat subcutaneous tissue with or without plasma components as the binder of ceramic granules. By analyzing the expression of two reliable osteoclast markers, we detected tartrate

  20. Evaluation of thermal stress in hydroxyapatite film fabricated by powder jet deposition.

    PubMed

    Akatsuka, Ryo; Matsumura, Ken; Noji, Miyoko; Kuriyagawa, Tsunemoto; Sasaki, Keiichi

    2013-10-01

    This study aimed to create a thick hydroxyapatite (HA) film on the surface of a human tooth via a powder jet deposition (PJD) device for dental handpieces, and to examine the microstructural and mechanical properties of the HA film. In particular, the effects of thermal stress on this film were evaluated. The HA film was created by blasting 3.18-μm HA particles, calcinated at 1,200°C, onto the enamel substrate at room temperature and atmospheric pressure. An HA film with an area of 3 mm × 3 mm was prepared and polished. The following HA film parameters were evaluated from the three-dimensional surface profile: surface roughness, Vickers hardness, and bonding strength before and after artificial aging induced by 500 cycles of thermal cycling (5-55°C). The HA particles in the deposited film were densely packed, and the surface of the HA film was unchanged after thermal cycling. There were also no significant differences in the hardness and the bonding strength of the HA film before and after thermal cycling. The HA film created in this study demonstrated excellent microstructural and mechanical properties, even after the application of thermal stress. © 2013 Eur J Oral Sci.

  1. Recent Developments in Suspension Plasma Sprayed Titanium Oxide and Hydroxyapatite Coatings

    NASA Astrophysics Data System (ADS)

    Jaworski, R.; Pawlowski, L.; Pierlot, C.; Roudet, F.; Kozerski, S.; Petit, F.

    2010-01-01

    The paper aims at reviewing of the recent studies related to the development of suspension plasma sprayed TiO2 and Ca5(PO4)3OH (hydroxyapatite, HA) coatings as well as their multilayer composites obtained onto stainless steel, titanium and aluminum substrates. The total thickness of the coatings was in the range 10 to 150 μm. The suspensions on the base of distilled water, ethanol and their mixtures were formulated with the use of fine commercial TiO2 pigment crystallized as rutile and HA milled from commercial spray-dried powder or synthesized from calcium nitrate and ammonium phosphate in an optimized reaction. The powder was crystallized as hydroxyapatite. Pneumatic and peristaltic pump liquid feeders were applied. The injection of suspension to the plasma jet was studied carefully with the use of an atomizer injector or a continuous stream one. The injectors were placed outside or inside of the anode-nozzle of the SG-100 plasma torch. The stream of liquid was tested under angle right or slightly backwards with regard to the torch axis. The sprayed deposits were submitted to the phase analysis by the use of x-ray diffraction. The content of anatase and rutile was calculated in the titanium oxide deposits as well as the content of the decomposition phases in the hydroxyapatite ones. The micro-Raman spectroscopy was used to visualize the area of appearance of some phases. Scratch test enabled to characterize the adhesion of the deposits, their microhardness and friction coefficient. The electric properties including electron emission, impedance spectroscopy, and dielectric properties of some coatings were equally tested.

  2. Preparation and Characterization of Lanthanum-Incorporated Hydroxyapatite Coatings on Titanium Substrates

    PubMed Central

    Lou, Weiwei; Dong, Yiwen; Zhang, Hualin; Jin, Yifan; Hu, Xiaohui; Ma, Jianfeng; Liu, Jinsong; Wu, Gang

    2015-01-01

    Titanium (Ti) has been widely used in clinical applications for its excellent biocompatibility and mechanical properties. However, the bioinertness of the surface of Ti has motivated researchers to improve the physicochemical and biological properties of the implants through various surface modifications, such as coatings. For this purpose, we prepared a novel bioactive material, a lanthanum-incorporated hydroxyapatite (La-HA) coating, using a dip-coating technique with a La-HA sol along with post-heat treatment. The XRD, FTIR and EDX results presented in this paper confirmed that lanthanum was successfully incorporated into the structure of HA. The La-HA coating was composed of rod-like particles which densely compacted together without microcracks. The results of the interfacial shear strength test indicated that the incorporation of lanthanum increased the bonding strength of the HA coating. The mass loss ratios under acidic conditions (pH = 5.5) suggested that the La-HA coatings have better acid resistance. The cytocompatibility of the La-HA coating was also revealed by the relative activity of alkaline phosphatase, cellular morphology and cell proliferation assay in vitro. The present study suggested that La-HA coated on Ti has promising potential for applications in the development of a new type of bioactive coating for metal implants. PMID:26404255

  3. Preparation of micro-porous bioceramic containing silicon-substituted hydroxyapatite and beta-tricalcium phosphate.

    PubMed

    Fuh, Lih-Jyh; Huang, Ya-Jing; Chen, Wen-Cheng; Lin, Dan-Jae

    2017-06-01

    Dimensional instability caused by sintering shrinkage is an inevitable drawback for conventional processing of hydroxyapatite (HA). A new preparation method for biphasic calcium phosphates was developed to increase micro pores and biodegradation without significant dimensional change. Powder pressed HA discs, under 100MPa, were immersed in a colloidal mixture of tetraethoxysilane (TEOS) and ammonium hydroxide for 10min, followed by drying, and then were sintered at 900°C, 1050°C, and 1200°C, respectively. Comparing with pure HA discs, the newly prepared product sintered up to 1200°C contained silicon substituted HA, beta-tricalcium phosphate, and calcium silicate with better micro-porosity, high specific surface area, less sintering shrinkage and the strength maintained. The cytocompatibility test demonstrated a better viability for D1 mice stem cells cultured on TEOS treated HA for 14days compared to the pure HA. This simple TEOS sol-gel pretreatment has the potential to be applied to any existing manufacturing process of HA scaffold for better control of sintering shrinkage, create micropores, and increase biodegradation. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. In vitro corrosion and cytocompatibility properties of nano-whisker hydroxyapatite coating on magnesium alloy for bone tissue engineering applications.

    PubMed

    Yang, Huawei; Yan, Xueyu; Ling, Min; Xiong, Zuquan; Ou, Caiwen; Lu, Wei

    2015-03-17

    We report here the successful fabrication of nano-whisker hydroxyapatite (nHA) coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries.

  5. PCL-HA microscaffolds for in vitro modular bone tissue engineering.

    PubMed

    Totaro, Alessandra; Salerno, Aurelio; Imparato, Giorgia; Domingo, Concepción; Urciuolo, Francesco; Netti, Paolo Antonio

    2017-06-01

    The evolution of microscaffolds and bone-bioactive surfaces is a pivotal point in modular bone tissue engineering. In this study, the design and fabrication of porous polycaprolactone (PCL) microscaffolds functionalized with hydroxyapatite (HA) nanoparticles by means of a bio-safe and versatile thermally-induced phase separation process is reported. The ability of the as-prepared nanocomposite microscaffolds to support the adhesion, growth and osteogenic differentiation of human mesenchymal stem cells (hMSCs) in standard and osteogenic media and using dynamic seeding/culture conditions was investigated. The obtained results demonstrated that the PCL-HA nanocomposite microparticles had an enhanced interaction with hMSCs and induced their osteogenic differentiation, even without the exogenous addition of osteogenic factors. In particular, calcium deposition, alizarin red assay, histological analysis, osteogenic gene expression and collagen I secretion were assessed. The results of these tests demonstrated the formation of bone microtissue precursors after 28 days of dynamic culture. These findings suggest that PCL-HA nanocomposite microparticles represent an excellent platform for in vitro modular bone tissue engineering. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Mechanical properties of dental resin/composite containing urchin-like hydroxyapatite.

    PubMed

    Liu, Fengwei; Sun, Bin; Jiang, Xiaoze; Aldeyab, Sultan S; Zhang, Qinghong; Zhu, Meifang

    2014-12-01

    To investigate the reinforcing effect of urchin-like hydroxyapatite (UHA) in bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin (without silica nanoparticles) and dental composites (with silica nanoparticles), and explore the effect of HA filler morphologies and loadings on the mechanical properties. UHA was synthesized by a facile method of microwave irradiation and studied by X-ray diffraction (XRD), scanning electron microscope (SEM), and thermogravimetric analysis (TGA). Mechanical properties of the dental resin composites containing silanized UHA were tested by a universal mechanical testing machine. Analysis of variance was used for the statistical analysis of the acquired data. The fracture morphologies of tested composites were observed by SEM. Composites with silanized irregular particulate hydroxyapatite (IPHA) and hydroxyapatite whisker (HW) were prepared for comparative studies. Impregnation of lower loadings (5 wt% and 10 wt%) of silanized UHA into dental resin (without silica nanoparticles) substantially improved the mechanical properties; higher UHA loadings (20 wt% and 30 wt%) of impregnation continuously improved the flexural modulus and microhardness, while the strength would no longer be increased. Compared with silanized IPHA and HW, silanized UHA consisting of rods extending radially from center were embedded into the matrix closely and well dispersed in the composite, increasing filler-matrix interfacial contact area and combination. At higher filler loadings, UHA interlaced together tightly without affecting the mobility of monomer inside, which might bear higher loads during fracture of the composite, leading to higher strengths than those of dental resins with IPHA and HW. Besides, impregnation of silanized UHA into dental composites (with silica nanoparticles) significantly improved the strength and modulus. UHA could serve as novel reinforcing HA filler to improve the mechanical properties

  7. Development of wear resistant NFSS-HA novel biocomposites and study of their tribological properties for orthopaedic applications.

    PubMed

    Younesi, M; Bahrololoom, M E; Fooladfar, H

    2010-02-01

    Implants made of nickel free austenitic stainless steel can reduce the toxic effect of released nickel ion and compounds from the conventional stainless steels. On the other hand, hydroxyapatite is a ceramic which has been used in orthopaedic applications due to its good osteoconductivity, biocompatibility and bioactivity. However, there is no evidence in the literature up to now on producing composites based on nickel free stainless steel and hydroxyapatite and study of their tribology. The aim of this work was to produce novel biocomposites made up of nickel free stainless steel with hydroxyapatite (prepared by heat treating bone ash) and studying their tribology under various loads in air and in Ringer's physiological solution. Different amounts of hydroxyapatite powder (10, 20, 30 and 40% Vol.) were added to this nickel free stainless steel powder to get the biocomposites. Variation of their density, hardness, wear resistance and friction with the ceramic (hydroxyapatite) content and wear load were investigated in air and in Ringer's solution. The density of the composites was decreased by increasing the volume percentage of the hydroxyapatite, while wear resistance of the composites was increased. The wear mechanism of these composites was changed by increasing the wear load and consequently the volume loss was enhanced dramatically. Furthermore, by increasing the sliding distance, the rate of volume loss was decreased slightly. The friction coefficient of the composites was also decreased by increasing the weight percentage of hydroxyapatite. Effect of the physiological Ringer's solution on wear resistance and friction coefficient of the composites was nearly negligible. The wear mechanisms of the samples were identified by studying the SEM images of the worn surfaces of the tested samples in different wear loads and HA contents. Copyright 2009 Elsevier Ltd. All rights reserved.

  8. Cellular proliferation, cellular viability, and biocompatibility of HA-ZnO composites.

    PubMed

    Saha, Naresh; Dubey, Ashutosh K; Basu, Bikramjit

    2012-01-01

    One of the important issues in the development of hydroxyapatite (HA)-based biomaterials is the prosthetic infection, which limits wider use of monolithic HA despite superior cellular response. Recently, we reported that ZnO addition to HA can induce bactericidal property. It is therefore important to assess how ZnO addition influences the cytotoxicity property and cell adhesion/proliferation on HA-ZnO composite surfaces in vitro. In the above perspective, the objective of this study is to investigate the cell type and material composition dependent cellular proliferation and viability of pressureless sintered HA-ZnO composites. The combination of cell viability data as well as morphological observations of cultured human osteoblast-like SaOS2 cells and mouse fibroblast L929 cells suggests that HA-ZnO composites containing 10 Wt % or lower ZnO exhibit the ability to support cell adhesion and proliferation. Both SaOS2 and L929 cells exhibit extensive multidirectional network of actin cytoskeleton and cell flattening on the lower ZnO containing (≤10 Wt %) HA-ZnO composites. The in vitro results illustrate how variation in ZnO content can influence significantly the cell vitality, as evaluated using MTT biochemical assay. Also, the critical statistical analysis reveals that ZnO addition needs to be carefully tailored to ensure good in vitro cytocompatibility. The underlying reasons for difference in biological properties are analyzed. It is suggested that surface wettability as well as dissolution of ZnO, both contribute to the observed differences in cellular viability and proliferation. Copyright © 2011 Wiley Periodicals, Inc.

  9. Hydroxyapatite-nanotube composites and coatings for orthopedic applications

    NASA Astrophysics Data System (ADS)

    Lahiri, Debrupa

    Hydroxyapatite (HA) has received wide attention in orthopedics, due to its biocompatibility and osseointegration ability. Despite these advantages, the brittle nature and low fracture toughness of HA often results in rapid wear and premature fracture of implant. Hence, there is a need to improve the fracture toughness and wear resistance of HA without compromising its biocompatibility. The aim of the current research is to explore the potential of nanotubes as reinforcement to HA for orthopedic implants. HA- 4 wt.% carbon nanotube (CNT) composites and coatings are synthesized by spark plasma sintering and plasma spraying respectively, and investigated for their mechanical, tribological and biological behavior. CNT reinforcement improves the fracture toughness (>90%) and wear resistance (>66%) of HA for coating and free standing composites. CNTs have demonstrated a positive influence on the proliferation, differentiation and matrix mineralization activities of osteoblasts, during in-vitro biocompatibility studies. In-vivo exposure of HA-CNT coated titanium implant in animal model (rat) shows excellent histocompatibility and neobone integration on the implant surface. The improved osseointegration due to presence of CNTs in HA is quantified by the adhesion strength measurement of single osteoblast using nano-scratch technique. Considering the ongoing debate about cytotoxicity of CNTs in the literature, the present study also suggests boron nitride nanotube (BNNT) as an alternative reinforcement. BNNT with the similar elastic modulus and strength as CNT, were added to HA. The resulting composite having 4 wt.% BNNTs improved the fracture toughness (˜85%) and wear resistance (˜75%) of HA in the similar range as HA-CNT composites. BNNTs were found to be non-cytotoxic for osteoblasts and macrophages. In-vitro evaluation shows positive role of BNNT in osteoblast proliferation and viability. Apatite formability of BNNT surface in ˜4 days establishes its osseointegration

  10. Making Polymeric Microspheres

    NASA Technical Reports Server (NTRS)

    Rhim, Won-Kyu; Hyson, Michael T.; Chung, Sang-Kun; Colvin, Michael S.; Chang, Manchium

    1989-01-01

    Combination of advanced techniques yields uniform particles for biomedical applications. Process combines ink-jet and irradiation/freeze-polymerization techniques to make polymeric microspheres of uniform size in diameters from 100 to 400 micrometer. Microspheres used in chromatography, cell sorting, cell labeling, and manufacture of pharmaceutical materials.

  11. Electrophoretic deposition of graphene oxide reinforced chitosan-hydroxyapatite nanocomposite coatings on Ti substrate.

    PubMed

    Shi, Y Y; Li, M; Liu, Q; Jia, Z J; Xu, X C; Cheng, Y; Zheng, Y F

    2016-03-01

    Electrophoretic deposition (EPD) is a facile and feasible technique to prepare functional nanocomposite coatings for application in orthopedic-related implants. In this work, a ternary graphene oxide-chitosan-hydroxyapatite (GO-CS-HA) composite coating on Ti substrate was successfully fabricated by EPD. Coating microstructure and morphologies were investigated by scanning electron microscopy, contact angle test, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. It was found GO-CS surface were uniformly decorated by HA nanoparticles. The potentiodynamic polarization test in simulated body fluid indicated that the GO-CS-HA coatings could provide effective protection of Ti substrate from corrosion. This ternary composite coating also exhibited good biocompatibility during incubation with MG63 cells. In addition, the nanocomposite coatings could decrease the attachment of Staphylococcus aureus.

  12. A novel route for synthesis of nanocrystalline hydroxyapatite from eggshell waste.

    PubMed

    Siva Rama Krishna, D; Siddharthan, A; Seshadri, S K; Sampath Kumar, T S

    2007-09-01

    The eggshell waste has been value engineered to a nanocrystalline hydroxyapatite (HA) by microwave processing. To highlight the advantages of eggshell as calcium precursor in the synthesis of HA (OHA), synthetic calcium hydroxide was also used to form HA (SHA) following similar procedure and were compared with a commercially available pure HA (CHA). All the HAs were characterized by X-ray powder diffraction (XRD) method, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and specific surface area measurements. Nanocrystalline nature of OHA is revealed through characteristic broad peaks in XRD patterns, platelets of length 33-50 nm and width 8-14 nm in TEM micrograph and size calculations from specific surface area measurements. FT-IR spectra showed characteristic bands of HA and additionally peaks of carbonate ions. The cell parameter calculations suggest the formation of carbonated HA of B-type. The OHA exhibits superior sinterability in terms of hardness and density than both SHA and CHA may be due to larger surface area of its spherulite structure. The in vitro dissolution study shows longer stability in phosphate buffer and cell culture test using osteoblast cells establishes biocompatibility of OHA.

  13. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Silva, Suresh de, E-mail: suresh.desilva@unsw.edu.au; Mackie, Simon; Aslan, Peter

    BackgroundIntra-arterial brachytherapy with yttrium-90 ({sup 90}Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of {sup 90}Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with {sup 90}Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extentmore » of tissue necrosis from {sup 90}Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with {sup 90}Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the {sup 90}Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10{sup 6}) of bland microspheres.ConclusionThis study showed that radioembolization with {sup 90}Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of {sup 90}Y resin microspheres for the localized treatment of kidney tumors.« less

  14. Boron nitride nanotube reinforced hydroxyapatite composite: mechanical and tribological performance and in-vitro biocompatibility to osteoblasts.

    PubMed

    Lahiri, Debrupa; Singh, Virendra; Benaduce, Ana Paula; Seal, Sudipta; Kos, Lidia; Agarwal, Arvind

    2011-01-01

    This study proposes boron nitride nanotube (BNNT) reinforced hydroxyapatite (HA) as a novel composite material for orthopedic implant applications. The spark plasma sintered (SPS) composite structure shows higher density compared to HA. Minimal lattice mismatch between HA and BNNT leads to coherent bonding and strong interface. HA-4 wt% BNNT composite offers excellent mechanical properties-120% increment in elastic modulus, 129% higher hardness and 86% more fracture toughness, as compared to HA. Improvements in the hardness and fracture toughness are related to grain refinement and crack bridging by BNNTs. HA-BNNT composite also shows 75% improvement in the wear resistance. The wear morphology suggests localized plastic deformation supported by the sliding of outer walls of BNNT. Osteoblast proliferation and cell viability show no adverse effect of BNNT addition. HA-BNNT composite is, thus, envisioned as a potential material for stronger orthopedic implants. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Development of electrochemical folic acid sensor based on hydroxyapatite nanoparticles.

    PubMed

    Kanchana, P; Sekar, C

    2015-02-25

    We report the synthesis of hydroxyapatite (HA) nanoparticles (NPs) by a simple microwave irradiation method and its application as sensing element for the precise determination of folic acid (FA) by electrochemical method. The structure and composition of the HA NPs characterized using XRD, FTIR, Raman and XPS. SEM and EDX studies confirmed the formation of elongated spherical shaped HA NPs with an average particle size of about 34 nm. The HA NPs thin film on glassy carbon electrode (GCE) were deposited by drop casting method. Electrocatalytic behavior of FA in the physiological pH 7.0 was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. The fabricated HA/GCE exhibited a linear calibration plot over a wide FA concentration ranging from 1.0×10(-7) to 3.5×10(-4) M with the detection limit of 75 nM. In addition, the HA NPs modified GCE showed good selectivity toward the determination of FA even in the presence of a 100-fold excess of ascorbic acid (AA) and 1000-fold excess of other common interferents. The fabricated biosensor exhibits good sensitivity and stability, and was successfully applied for the determination of FA in pharmaceutical samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Development of electrochemical folic acid sensor based on hydroxyapatite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kanchana, P.; Sekar, C.

    2015-02-01

    We report the synthesis of hydroxyapatite (HA) nanoparticles (NPs) by a simple microwave irradiation method and its application as sensing element for the precise determination of folic acid (FA) by electrochemical method. The structure and composition of the HA NPs characterized using XRD, FTIR, Raman and XPS. SEM and EDX studies confirmed the formation of elongated spherical shaped HA NPs with an average particle size of about 34 nm. The HA NPs thin film on glassy carbon electrode (GCE) were deposited by drop casting method. Electrocatalytic behavior of FA in the physiological pH 7.0 was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. The fabricated HA/GCE exhibited a linear calibration plot over a wide FA concentration ranging from 1.0 × 10-7 to 3.5 × 10-4 M with the detection limit of 75 nM. In addition, the HA NPs modified GCE showed good selectivity toward the determination of FA even in the presence of a 100-fold excess of ascorbic acid (AA) and 1000-fold excess of other common interferents. The fabricated biosensor exhibits good sensitivity and stability, and was successfully applied for the determination of FA in pharmaceutical samples.

  17. Fracture modes under uniaxial compression in hydroxyapatite scaffolds fabricated by robocasting.

    PubMed

    Miranda, Pedro; Pajares, Antonia; Saiz, Eduardo; Tomsia, Antoni P; Guiberteau, Fernando

    2007-12-01

    The fracture modes of hydroxyapatite (HA) scaffolds fabricated by direct-write assembly (robocasting) are analyzed in this work. Concentrated HA inks with suitable viscoelastic properties were developed to enable the fabrication of prototype structures consisting of a 3-D square mesh of interpenetrating rods. The fracture behavior of these model scaffolds under compressive stresses is determined from in situ uniaxial tests performed in two different directions: perpendicular to the rods and along one of the rod directions. The results are analyzed in terms of the stress field calculated by finite element modeling (FEM). This analysis provides valuable insight into the mechanical behavior of scaffolds for bone tissue engineering applications fabricated by robocasting. Copyright 2007 Wiley Periodicals, Inc.

  18. Development and characterization of titanium-containing hydroxyapatite for medical applications.

    PubMed

    Huang, J; Best, S M; Bonfield, W; Buckland, Tom

    2010-01-01

    Hydroxyapatite containing levels of titanium (TiHA) of up to 1.6 wt.% has been produced via a chemical co-precipitation route. The distribution of Ti was seen by transmission electron microscopy/energy-dispersive X-ray analysis to be uniform throughout as-prepared nanosized TiHA particles (20 nm x 100 nm). The incorporation of Ti into the HA structure was found to influence the ceramic microstructure on sintering and the grain size was found to decrease from 0.89 microm with HA to 0.63 microm with 0.8 wt.% TiHA (0.8 TiHA) and 0.45 microm with 1.6 wt.% TiHA (1.6 TiHA). Rietveld refinement analysis showed that there was a proportional increase in both the a and c axis with incorporation of Ti into the HA lattice structure, leading to an increase in the cell volume with the addition of Ti. Fourier transform-Raman analysis showed a slight increase in the ratio of O-H/P-O peaks on TiHA, in comparison with HA. A bone-like apatite layer was formed on the surface of TiHA after immersion in simulated body fluid for 3 days, which demonstrated the high in vitro bioactivity of TiHA. In vitro culture with primary human osteoblast (HOB) cells revealed that TiHA was able to support the growth and proliferation of HOB cells in vitro, with a significantly higher cell activity being observed on 0.8 TiHA after 7 days of culture in comparison with that on HA. Well-organized actin cytoskeletal protein was developed after 1 day of culture, and an increase in cell filopodia (attachment) was observed on TiHA sample surfaces. The results indicate that TiHA has great potential for biomedical applications.

  19. Mussel-inspired nano-building block assemblies for mimicking extracellular matrix microenvironments with multiple functions.

    PubMed

    Wang, Zhenming; Jia, Zhanrong; Jiang, Yanan; Li, Pengfei; Han, Lu; Lu, Xiong; Ren, Fuzeng; Wang, Kefeng; Yuan, Huiping

    2017-08-03

    The assembly of nano-building blocks is an effective way to produce artificial extracellular matrix microenvironments with hierarchical micro/nano structures. However, it is hard to assemble different types of nano-building blocks, to form composite coatings with multiple functions, by traditional layer-by-layer (LbL) self-assembly methods. Inspired by the mussel adhesion mechanism, we developed polydopamine (PDA)-decorated bovine serum albumin microspheres (BSA-MS) and nano-hydroxyapatite (nano-HA), and assembled them to form bioactive coatings with micro/nano structures encapsulating bone morphogenetic protein-2 (BMP-2). First, PDA-decorated nano-HA (nano-pHA) was obtained by oxidative polymerization of dopamine on nano-HA. Second, BMP-2-encapsulated BSA microspheres were prepared through desolvation, and then were also decorated by PDA (pBSA-MS). Finally, the nano-pHA and pBSA-MS were assembled using the adhesive properties of PDA. Bone marrow stromal cell cultures and in vivo implantation, showed that the pHA/pBSA (BMP-2) coatings can promote cell adhesion, proliferation, and benefited for osteoinductivity. PDA decoration was also applied to assemble various functional nanoparticles, such as nano-HA, polystyrene, and Fe 3 O 4 nanoparticles. In summary, this study provides a novel strategy for the assembly of biofunctional nano-building blocks, which surpasses traditional LbL self-assembly of polyelectrolytes, and can find broad applications in bioactive agents delivery or multi-functional coatings.

  20. Mechanical properties and crystallization behavior of hydroxyapatite/poly(butylenes succinate) composites.

    PubMed

    Guo, Wenmin; Zhang, Yihe; Zhang, Wei

    2013-09-01

    Biodegradable synthetic polymers have attracted much attention nowadays, and more and more researches have been done on biodegradable polymers due to their excellent mechanical properties, biocompatibility, and biodegradability. In this work, hydroxyapatite (HA) particles were melt-mixing with poly (butylenes succinate) (PBS) to prepare the material, which could be used in the biomedical industry. To develop high-performance PBS for cryogenic engineering applications, it is necessary to investigate the cryogenic mechanical properties and crystallization behavior of HA/PBS composites. Cryogenic mechanical behaviors of the composites were studied in terms of tensile and impact strength at the glass transition temperature (-30°C) and compared to their corresponding behaviors at room temperature. With the increase of HA content, the crystallization of HA/PBS composites decreased and crystallization onset temperature shifted to a lower temperature. The diameter of spherulites increased at first and decreased with a further HA content. At the same time, the crystallization rate became slow when the HA content was no more than 15wt% and increased when HA content reached 20wt%. In all, the results we obtained demonstrate that HA/PBS composites reveal a better tensile strength at -30°C in contrast to the strength at room temperature. HA particles with different amount affect the crystallization of PBS in different ways. Copyright © 2013 Wiley Periodicals, Inc.

  1. A new hydroxyapatite-based biocomposite for bone replacement.

    PubMed

    Bellucci, Devis; Sola, Antonella; Gazzarri, Matteo; Chiellini, Federica; Cannillo, Valeria

    2013-04-01

    Since the 1970s, various types of ceramic, glass and glass-ceramic materials have been proposed and used to replace damaged bone in many clinical applications. Among them, hydroxyapatite (HA) has been successfully employed thanks to its excellent biocompatibility. On the other hand, the bioactivity of HA and its reactivity with bone can be improved through the addition of proper amounts of bioactive glasses, thus obtaining HA-based composites. Unfortunately, high temperature treatments (1200°C÷1300°C) are usually required in order to sinter these systems, causing the bioactive glass to crystallize into a glass-ceramic and hence inhibiting the bioactivity of the resulting composite. In the present study novel HA-based composites are realized and discussed. The samples can be sintered at a relatively low temperature (800 °C), thanks to the employment of a new glass (BG_Ca) with a reduced tendency to crystallize compared to the widely used 45S5 Bioglass®. The rich glassy phase, which can be preserved during the thermal treatment, has excellent effects in terms of in vitro bioactivity; moreover, compared to composites based on 45S5 Bioglass® having the same HA/glass proportions, the samples based on BG_Ca displayed an earlier response in terms of cell proliferation. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. In Vitro Corrosion and Cytocompatibility Properties of Nano-Whisker Hydroxyapatite Coating on Magnesium Alloy for Bone Tissue Engineering Applications

    PubMed Central

    Yang, Huawei; Yan, Xueyu; Ling, Min; Xiong, Zuquan; Ou, Caiwen; Lu, Wei

    2015-01-01

    We report here the successful fabrication of nano-whisker hydroxyapatite (nHA) coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries. PMID:25789500

  3. Effects of sol-gel processing parameters on the phases and microstructures of HA films.

    PubMed

    Wang, Diangang; Chen, Chuanzhong; Liu, Xiuna; Lei, Tingquan

    2007-06-15

    Bioactive hydroxyapatite (HA) films were fabricated by a sol-gel method and triethylphosphate and calcium nitrate were used as the phosphorus and calcium precursors, respectively. The effects of the heat treatment temperature, pH level and substrate materials on the phases and microstructures of HA films were studied by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and electronic probe microanalysis (EPMA) and so on. The results show that all the sol-gel films are composed of the phases of HA, CaO, TiO(2) and CaTiO(3). With increasing the calcining temperature, the crystallinity of the films increases, the structure becomes more compact and changes from granular and lamellar to cellular structure, and the Ca/P ratio increases slightly because of the loss of P in the films. The addition of ammonia (adjusting the pH level to be about 7.5) can increase the HA content in the films, and the difference of substrate materials only has a little influence on the microstructure of the sol-gel films.

  4. Development of HA/Ag-NPs Composite Coating from Green Process for Hip Applications.

    PubMed

    Lozoya-Rodríguez, Denisse A; de Lima, Renata; Fraceto, Leonardo F; Ledezma Pérez, Antonio; Bazaldua Domínguez, Mercedes; Gómez Batres, Roberto; Reyes Rojas, Armando; Orozco Carmona, Víctor

    2017-08-08

    In the present study, biological hydroxyapatite (HA) was obtained from bovine bones through a thermal process. A total of 0% and 1% of silver nanoparticles (Ag-NPs) synthesized from Opuntia ficus (nopal) were added to the biological hydroxyapatite coatings using an atmospheric plasma spray (APS) on a Ti6Al4V substrate. Following this, its antimicrobial efficiency was evaluated against the following bacterial strains: Escherichia coli , Staphylococcus aureus , and Pseudomonas aeruginosa . This was conducted according to the Japanese Industrial Standard (JIS) Z2801:2000 "Antimicrobial Product-Test for Antimicrobial Activity and Efficacy". Scanning electron microscopy (SEM) showed that the silver nanoparticles (Ag-NPs) were evenly distributed on the coating surface. Energy dispersive X-ray spectroscopy (EDX) shows that apatite deposition occurs on a daily basis, maintaining a Ca/P rate between 2.12 and 1.45. Biocompatibility properties were evaluated with osteoblast-like cells (MC3T3-E1) by single-cell gel electrophoresis assay and Tali image cytometry.

  5. Effect of Induced Periimplantitis on Dental Implants With and Without Ultrathin Hydroxyapatite Coating.

    PubMed

    Madi, Marwa; Zakaria, Osama; Ichinose, Shizuko; Kasugai, Shohei

    2016-02-01

    The aim of this study was to compare the effect of ligature-induced periimplantitis on dental implants with and without hydroxyapatite (HA) coat. Thirty-two dental implants (3.3 mm wide, 13 mm long) with 4 surface treatments (8 implant/group) (M: machined, SA: sandblasted acid etched, S: sputter HA coat and P: plasma-sprayed HA coat) were inserted into canine mandibles. After 12 weeks, oral hygiene procedures were stopped and silk ligatures were placed around the implant abutments to allow plaque accumulation for the following 16 weeks. Implants with the surrounding tissues were retrieved and prepared for histological examination. Bone-to-implant contact (BIC) and implant surfaces were examined using scanning electron microscopy and energy dispersive x-ray spectroscopy. Histological observation revealed marginal bone loss and large inflammatory cell infiltrates in the periimplant soft tissue. Sputter HA implants showed the largest BIC (98.1%) and machined implant showed the smallest values (70.4%). After 28 weeks, thin sputter HA coat was almost completely dissolved, whereas plasma-sprayed HA coat showed complete thickness preservation. Thin sputter HA-coated implants showed more bone implant contact and less marginal bone loss than thick HA-coated implants under periimplantitis condition.

  6. Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements

    PubMed Central

    Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

    2014-01-01

    Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca2+ release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media. PMID:25866411

  7. Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

    PubMed

    Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

    2014-04-01

    Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca 2+ release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

  8. Water-based sol-gel synthesis of hydroxyapatite: process development.

    PubMed

    Liu, D M; Troczynski, T; Tseng, W J

    2001-07-01

    Hydroxyapatite (HA) ceramics were synthesized using a sol-gel route with triethyl phosphite and calcium nitrate as phosphorus and calcium precursors, respectively. Two solvents, water and anhydrous ethanol, were used as diluting media for HA sol preparation. The sols were stable and no gelling occurred in ambient environment for over 5 days. The sols became a white gel only after removal of the solvents at 60 degrees C. X-ray diffraction showed that apatitic structure first appeared at a temperature as low as 350 degrees C. The crystal size and the HA content in both gels increase with increasing calcination temperature. The type of initial diluting media (i.e., water vs. anhydrous ethanol) did not affect the microstructural evolution and crystallinity of the resulting HA ceramic. The ethanol-based sol dip-coated onto a Ti substrate, followed by calcination at 450 degrees C, was found to be porous with pore size ranging from 0.3 to 1 microm. This morphology is beneficial to the circulation of physiological fluid when the coating is used for biomedical applications. The satisfactory adhesion between the coating and substrate suggests its suitability for load-bearing uses.

  9. The pathway to intelligent implants: osteoblast response to nano silicon-doped hydroxyapatite patterning

    PubMed Central

    Munir, G.; Koller, G.; Di Silvio, L.; Edirisinghe, M. J.; Bonfield, W.; Huang, J.

    2011-01-01

    Bioactive hydroxyapatite (HA) with addition of silicon (Si) in the crystal structure (silicon-doped hydroxyapatite (SiHA)) has become a highly attractive alternative to conventional HA in bone replacement owing to the significant improvement in the in vivo bioactivity and osteoconductivity. Nanometre-scaled SiHA (nanoSiHA), which closely resembles the size of bone mineral, has been synthesized in this study. Thus, the silicon addition provides an extra chemical cue to stimulate and enhance bone formation for new generation coatings, and the next stage in metallic implantation design is to further improve cellular adhesion and proliferation by control of cell alignment. Topography has been found to provide a powerful set of signals for cells and form contact guidance. Using the recently developed novel technique of template-assisted electrohydrodynamic atomization (TAEA), patterns of pillars and tracks of various dimensions of nanoSiHA were achieved. Modifying the parameters of TAEA, the resolution of pattern structures was controlled, enabling the topography of a substrate to be modified accordingly. Spray time, flow rate and distance between the needle and substrate were varied to improve the pattern formation of pillars and tracks. The 15 min deposition time provided the most consistent patterned topography with a distance of 50 mm and flow rate of 4 µl min−1. A titanium substrate was patterned with pillars and tracks of varying widths, line lengths and distances under the optimized TAEA processing condition. A fast bone-like apatite formation rate was found on nanoSiHA after immersion in simulated body fluid, thus demonstrating its high in vitro bioactivity. Primary human osteoblast (HOB) cells responded to SiHA patterns by stretching of the filopodia between track and pillar, attaching to the apex of the pillar pattern and stretching between two. HOB cells responded to the track pattern by elongating along and between the track, and the length of HOB cells

  10. Porous alumina-hydroxyapatite composites through protein foaming-consolidation method.

    PubMed

    Sopyan, I; Fadli, A; Mel, M

    2012-04-01

    This report presents physical characterization and cell culture test of porous alumina-hydroxyapatite (HA) composites fabricated through protein foaming-consolidation technique. Alumina and HA powders were mixed with yolk and starch at an adjusted ratio to make slurry. The resulting slip was poured into cylindrical shaped molds and followed by foaming and consolidation via 180 °C drying for 1 h. The obtained green bodies were burned at 600 °C for 1 h, followed by sintering at temperatures of 1200-1550 °C for 2 h. Porous alumina-HA bodies with 26-77 vol.% shrinkage, 46%-52% porosity and 0.1-6.4 MPa compressive strength were obtained. The compressive strength of bodies increased with the increasing sintering temperatures. The addition of commercial HA in the body was found to increase the compressive strength, whereas the case is reverse for sol-gel derived HA. Biocompatibility study of porous alumina-HA was performed in a stirred tank bioreactor using culture of Vero cells. A good compatibility of the cells to the porous microcarriers was observed as the cells attached and grew at the surface of microcarriers at 8-120 cultured hours. The cell growth on porous alumina microcarrier was 0.015 h(-1) and increased to 0.019 h(-1) for 0.3 w/w HA-to-alumina mass ratio and decreased again to 0.017 h(-1) for 1.0 w/w ratio. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Combined Amendments of Nano-hydroxyapatite Immobilized Cadmium in Contaminated Soil-Potato (Solanum tuberosum L.) System.

    PubMed

    Liu, Chang; Wang, Lei; Yin, Jiang; Qi, Lipan; Feng, Yan

    2018-04-01

    The toxicity of cadmium (Cd) has posed major public health concern in crops grown in the Cd-contaminated soils. The effects of five amendments, nano-hydroxyapatite (n-HA) and it combined with lime, zeolite, bone mill and fly ash on Cd immobilization in soils and uptake in potatoes, were investigated in a contaminated soil by pot experiments. The result showed that the applications of combined amendments significantly decreased the bioavailable Cd concentrations extracted by TCLP, DTPA-TEA and MgCl 2 in the contaminated soils, and changed the soluble and exchangeable and specifically sorbed fractions to oxide-bound and organic-bound fractions. Compared to the control group, the concentrations of Cd in the potato tubers grown in n-HA, n-HA + Fly ash, n-HA + Lime, n-HA + Bone mill and n-HA + Zeolite soil were reduced 17.4%, 20.7%, 15.2%, 32.6% and 39.1%, respectively. Nano-hydroxyapatite combined amendments was more effective in reducing bioavailable Cd concentrations and Cd accumulations in potatoes, especially for n-HA + Z.

  12. The effects of hydroxyapatite coatings on stress distribution near the dental implant bone interface

    NASA Astrophysics Data System (ADS)

    Jiang, W.; Wang, W. D.; Shi, X. H.; Chen, H. Z.; Zou, W.; Guo, Z.; Luo, J. M.; Gu, Z. W.; Zhang, X. D.

    2008-11-01

    The effects of different thickness of hydroxyapatite (HA) coatings on bone stress distribution near the dental implant-bone interface are very important factors for the HA-coated dental implant design and clinical application. By means of finite element analysis (FEA), the bone stress distributions near the dental implant coated with different thicknesses from 0 to 200 μm were calculated and analyzed under the 200 N chewing load. In all cases, the maximal von Mises stresses in the bone are at the positions near the neck of dental implant on the lingual side, and decrease with the increase of the HA coatings thickness. The HA coatings weaken the stress concentration and improve the biomechanical property in the bone, however, in HA coatings thickness range of 60-120 μm, the distinctions of that benefit are not obvious. In addition, considering the technical reason of HA coatings, we conclude that thickness of HA coatings range from 60 to 120 μm would be the better choice for clinical application.

  13. Nanophase hydroxyapatite coatings for dental and orthopedic applications

    NASA Astrophysics Data System (ADS)

    Sato, Michiko

    In order to improve dental and orthopedic implant performance, the objective of this study was to synthesize nanocrystalline hydroxyapatite (HA) powders to coat metals (specifically, titanium and tantalum). Precipitated HA powders were either sintered in order to produce UltraCaP HA (or microcrystalline size HA) or were treated hydrothermally to produce nanocrystalline HA. Some of the UltraCaP and nanocrystalline HA powders were doped with yttrium (Y) since previous in vitro studies demonstrated that Y-doped HA in bulk improved osteoblast (or bone-forming cell) function over undoped HA. The nanocrystalline HA powders were also mixed with nanophase titania powders because previous studies demonstrated that titania/HA composite coatings increased coating adhesive strength and HA nucleation. These powders were then deposited onto titanium by a novel room-temperature process, called IonTiteT(TM). The results demonstrated that the chemical properties and crystallite size of the original HA powders were maintained in the coatings. More importantly, in vitro studies showed increased osteoblast (bone-forming cell) adhesion on the single phase nanocrystalline HA and nano-titania/HA coatings compared to traditionally used plasma-sprayed HA coatings and uncoated metals. Results further demonstrated greater amounts of calcium deposition by osteoblasts cultured on nanocrystalline HA coatings compared to UltraCaP coatings and conventionally used plasma-sprayed HA coatings. To elucidate mechanisms that influenced osteoblast functions on the HA coatings, the amount of proteins (fibronectin and vitronectin) onto the HA powders and the adsorbed fibronectin conformation were investigated. Exposure of cell integrin binding domains (in fibronectin III10 segments) was greater in fibronectin adsorbed onto 1.2 mole% Y-doped UltraCaP HA coatings compared to nanocrystalline HA coatings tested. However, 1.2 mole% Y-doped UltraCaP HA coatings did not increase mineralization by osteoblasts

  14. Development of strontium and magnesium substituted porous hydroxyapatite/poly(3,4-ethylenedioxythiophene) coating on surgical grade stainless steel and its bioactivity on osteoblast cells.

    PubMed

    Gopi, D; Ramya, S; Rajeswari, D; Surendiran, M; Kavitha, L

    2014-02-01

    The present study deals with the successful development of bilayer coatings by electropolymerisation of poly(3,4-ethylenedioxythiophene) (PEDOT) on surgical grade stainless steel (316L SS) followed by the electrodeposition of strontium (Sr) and magnesium (Mg) substituted porous hydroxyapatite (Sr, Mg-HA). The bilayer coatings were characterised by Fourier transform infrared spectroscopy (FT-IR) and high resolution scanning electron microscopy (HRSEM). Corrosion resistance of the obtained coatings was investigated in Ringer's solution by electrochemical techniques and the results were in good agreement with those obtained from chemical analysis, namely inductively coupled plasma atomic emission spectrometry (ICP-AES). Also, the mechanical and biological properties of the bilayer coatings were analyzed. From the obtained results it was evident that the PEDOT/Sr, Mg-HA bilayer exhibited greater adhesion strength than the Sr, Mg-HA coated 316L SS. In vitro cell adhesion test of the Sr, Mg-HA coating on PEDOT coated specimen is found to be more bioactive compared to that of the single substituted hydroxyapatite (Sr or Mg-HA) on the PEDOT coated 316L SS. Thus, the PEDOT/Sr, Mg-HA bilayer coated 316L SS can serve as a prospective implant material for biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Surface characteristics of a novel hydroxyapatite-coated dental implant

    PubMed Central

    Jung, Ui-Won; Hwang, Ji-Wan; Choi, Da-Yae; Hu, Kyung-Seok; Kwon, Mi-Kyung; Choi, Seong-Ho

    2012-01-01

    Purpose This study evaluated the surface characteristics and bond strength produced using a novel technique for coating hydroxyapatite (HA) onto titanium implants. Methods HA was coated on the titanium implant surface using a super-high-speed (SHS) blasting method with highly purified HA. The coating was performed at a low temperature, unlike conventional HA coating methods. Coating thickness was measured. The novel HA-coated disc was fabricated. X-ray diffraction analysis was performed directly on the disc to evaluate crystallinity. Four novel HA-coated discs and four resorbable blast medium (RBM) discs were prepared. Their surface roughnesses and areas were measured. Five puretitanium, RBM-treated, and novel HA-coated discs were prepared. Contact angle was measured. Two-way analysis of variance and the post-hoc Scheffe's test were used to analyze differences between the groups, with those with a probability of P<0.05 considered to be statistically significant. To evaluate exfoliation of the coating layer, 7 sites on the mandibles from 7 mongrel dogs were used. Other sites were used for another research project. In total, seven novel HA-coated implants were placed 2 months after extraction of premolars according to the manufacturer's instructions. The dogs were sacrificed 8 weeks after implant surgery. Implants were removed using a ratchet driver. The surface of the retrieved implants was evaluated microscopically. Results A uniform HA coating layer was formed on the titanium implants with no deformation of the RBM titanium surface microtexture when an SHS blasting method was used. Conclusions These HA-coated implants exhibited increased roughness, crystallinity, and wettability when compared with RBM implants. PMID:22586524

  16. Hierarchical Structure and Mechanical Improvement of an n-HA/GCO-PU Composite Scaffold for Bone Regeneration.

    PubMed

    Li, Limei; Zuo, Yi; Zou, Qin; Yang, Boyuan; Lin, Lili; Li, Jidong; Li, Yubao

    2015-10-14

    To improve the mechanical properties of bone tissue and achieve the desired bone tissue regeneration for orthopedic surgery, newly designed hydroxyapatite/polyurethane (HA/PU) porous scaffolds were developed via in situ polymerization. The results showed that the molecular modification of PU soft segments by glyceride of castor oil (GCO) can increase the scaffold compressive strength by 48% and the elastic modulus by 96%. When nano-HA (n-HA) particles were incorporated into the GCO-PU matrix, the compressive strength and elastic modulus further increased by 49 and 74%, from 2.91 to 4.34 MPa and from 95 to 165.36 MPa, respectively. The n-HA particles with fine dispersity not only improved the interface bonding with the GCO-PU matrix but also provided effective bioactivity for bonding with bone tissue. The hierarchical structure and mechanical quality of the n-HA/GCO-PU composite scaffold were determined to be appropriate for the growth of cells and the regeneration of bony tissues, demonstrating promising prospects for bone repair and regeneration.

  17. Characterization of gas tunnel type plasma sprayed hydroxyapatite-nanostructure titania composite coatings

    NASA Astrophysics Data System (ADS)

    Yugeswaran, S.; Kobayashi, A.; Ucisik, A. Hikmet; Subramanian, B.

    2015-08-01

    Hydroxyapatite (HA) can be coated onto metal implants as a ceramic biocompatible coating to bridge the growth between implants and human tissue. Meanwhile many efforts have been made to improve the mechanical properties of the HA coatings without affecting its bioactivity. In the present study, nanostructure titania (TiO2) was mixed with HA powder and HA-nanostructure TiO2 composite coatings were produced by gas tunnel type plasma spraying torch under optimized spraying conditions. For this purpose, composition of 10 wt% TiO2 + 90 wt% HA, 20 wt% TiO2 + 80 wt% HA and 30 wt% TiO2 + 70 wt% HA were selected as the feedstock materials. The phase, microstructure and mechanical properties of the coatings were characterized. The obtained results validated that the increase in weight percentage of nanostructure TiO2 in HA coating significantly increased the microhardness, adhesive strength and wear resistance of the coatings. Analysis of the in vitro bioactivity and cytocompatibility of the coatings were done using conventional simulated body fluid (c-SBF) solution and cultured green fluorescent protein (GFP) labeled marrow stromal cells (MSCs) respectively. The bioactivity results revealed that the composite coating has bio-active surface with good cytocompatibility.

  18. Mechanical properties, electrochemical corrosion and in-vitro bioactivity of yttria stabilized zirconia reinforced hydroxyapatite coatings prepared by gas tunnel type plasma spraying.

    PubMed

    Yugeswaran, S; Yoganand, C P; Kobayashi, A; Paraskevopoulos, K M; Subramanian, B

    2012-05-01

    Yttria stabilized zirconia reinforced hydroxyapatite coatings were deposited by a gas tunnel type plasma spray torch under optimum spraying conditions. For this purpose, 10, 20 and 30 wt% of yttria stabilized zirconia (YSZ) powders were premixed individually with hydroxyapatite (HA) powder and were used as the feedstocks for the coatings. The effect of YSZ reinforcement on the phase formation and mechanical properties of the coatings such as hardness, adhesive strength and sliding wear rates was examined. The results showed that the reinforcement of YSZ in HA could significantly enhance the hardness and adhesive strength of the coatings. The potentiodynamic polarization and impedance measurements showed that the reinforced coatings exhibited superior corrosion resistance compared to the HA coating in SBF solution. Further the results of the bioactivity test conducted by immersion of coatings in SBF showed that after 10 days of immersion of the obtained coatings with all the above compositions commonly exhibited the onset of bioactive apatite formation except for HA+10%YSZ coating. The cytocompatibility was investigated by culturing the green fluorescent protein (GFP)-labeled marrow stromal cells (MSCs) on the coating surface. The cell culture results revealed that the reinforced coatings have superior cell growth than the pure HA coatings. Copyright © 2012. Published by Elsevier Ltd.

  19. Effects of incorporation of HA/ZrO(2) into glass ionomer cement (GIC).

    PubMed

    Gu, Y W; Yap, A U J; Cheang, P; Khor, K A

    2005-03-01

    Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO(2))-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO(2) powders were heat treated at 700 degrees Celsius and 800 degrees Celsius for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO(2)-GICs. The effects of different volume percentages of HA/ZrO(2) powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO(2)-GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO(2) particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO(2) improved the mechanical properties of the HA/ZrO(2)-GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO(2)-GICs increased with increasing soak time due to the continuous formation of aluminium salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO(2)-GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO(2)-GICs were found to be much better than those of HA-GICs because ZrO(2) has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO(2) does not dissolve with increasing soaking time.

  20. MC3T3-E1 osteoblast attachment and proliferation on porous hydroxyapatite scaffolds fabricated with nanophase powder

    PubMed Central

    Smith, Ian O; McCabe, Laura R; Baumann, Melissa J

    2006-01-01

    Porous bone tissue engineering scaffolds were fabricated using both nano hydroxyapatite (nano HA) powder (20 nm average particle size) and micro HA powder (10 μm average particle size), resulting in sintered scaffolds of 59 vol% porosity and 8.6±1.9 μm average grain size and 72 vol% porosity and 588±55 nm average grain size, respectively. Scanning electron microscopy was used to measure both the grain size and pore size. MC3T3-E1 osteoblast (OB) attachment and proliferation on both nano HA and micro HA porous scaffolds were quantified. As expected, OB cell number was greater on nano HA scaffolds compared with similarly processed micro HA scaffolds 5 days after seeding, while OB attachment did not appear greater on the nano HA scaffolds (p<0.05). PMID:17722535

  1. Development of dental composites with reactive fillers that promote precipitation of antibacterial-hydroxyapatite layers.

    PubMed

    Aljabo, Anas; Abou Neel, Ensanya A; Knowles, Jonathan C; Young, Anne M

    2016-03-01

    The study aim was to develop light-curable, high strength dental composites that would release calcium phosphate and chlorhexidine (CHX) but additionally promote surface hydroxyapatite/CHX co-precipitation in simulated body fluid (SBF). 80 wt.% urethane dimethacrylate based liquid was mixed with glass fillers containing 10 wt.% CHX and 0, 10, 20 or 40 wt.% reactive mono- and tricalcium phosphate (CaP). Surface hydroxyapatite layer thickness/coverage from SEM images, Ca/Si ratio from EDX and hydroxyapatite Raman peak intensities were all proportional to both time in SBF and CaP wt.% in the filler. Hydroxyapatite was, however, difficult to detect by XRD until 4 weeks. XRD peak width and SEM images suggested this was due to the very small size (~10 nm) of the hydroxyapatite crystallites. Precipitate mass at 12 weeks was 22 wt.% of the sample CaP total mass irrespective of CaP wt.% and up to 7 wt.% of the specimen. Early diffusion controlled CHX release, assessed by UV spectrometry, was proportional to CaP and twice as fast in water compared with SBF. After 1 week, CHX continued to diffuse into water but in SBF, became entrapped within the precipitating hydroxyapatite layer. At 12 weeks CHX formed 5 to 15% of the HA layer with 10 to 40 wt.% CaP respectively. Despite linear decline of strength and modulus in 4 weeks from 160 to 101 MPa and 4 to 2.4 GPa, respectively, upon raising CaP content, all values were still within the range expected for commercial composites. The high strength, hydroxyapatite precipitation and surface antibacterial accumulation should reduce tooth restoration failure due to fracture, aid demineralised dentine repair and prevent subsurface carious disease respectively. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Synthesis and characterization of bovine femur bone hydroxyapatite containing silver nanoparticles for the biomedical applications

    NASA Astrophysics Data System (ADS)

    Nirmala, R.; Sheikh, Faheem A.; Kanjwal, Muzafar A.; Lee, John Hwa; Park, Soo-Jin; Navamathavan, R.; Kim, Hak Yong

    2011-05-01

    Bovine femur bone hydroxyapatite (HA) containing silver (Ag) nanoparticles was synthesized by thermal decomposition method and subsequent reduction of silver nitrate with N, N-dimethylformamide (DMF) in the presence of poly(vinylacetate) (PVAc). The structural, morphological, and chemical properties of the HA-Ag nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). TEM images showed that the Ag nanoparticles with size ranging from 8 to 20 nm and were arranged at the periphery of HA crystals. Bactericidal activity of HA-Ag with different concentration of Ag nanoparticles immobilized on the surface of HA was investigated against gram-positive Staphylococcus aureus ( S. aureus, non-MRSA), Methicillin resistant S. aureus (MRSA) and gram-negative Escherichia coli ( E. coli) by the disc diffusion susceptibility test. The HA-Ag nanoparticles showed that broad spectrum activity against non-MRSA, MRSA, and E. coli bacterial strains.

  3. Coupling of HDPE/hydroxyapatite composites by silane-based methodologies.

    PubMed

    Sousa, R A; Reis, R L; Cunha, A M; Bevis, M J

    2003-06-01

    Several coupling treatments based on silane chemicals were investigated for the development of high density (HDPE)/hydroxyapatite (HA) composites. Two HA powders, sintered HA (HAs) and non sintered HA (HAns), were studied in combination with five silanes, namely y-methacryloxy propyltrimethoxy silane (MEMO), 3-(2-aminoethyl)aminopropyltrimethoxy silane (DAMO), vinyltrimethoxy silane (VTMO), 3-aminopropyltriethoxy silane (AMEO) and trimethoxypropyl silane (PTMO). The HA particles were treated by a dipping in method or by spraying with silane solutions. After drying, the treated powders were compounded with HDPE or HDPE with acrylic acid and/or organic peroxide and subsequently compression molded. The tensile test specimens obtained from the molded plates were tensile tested and their fracture surfaces were observed by scanning electron microscopy (SEM). For the sintered HA (HAs) composites, the most effective coupling treatments concerning stiffness are those based on MEMO and AMEO. The low influence of these coupling procedures on strength is believed to be associated to the low volume fraction and the relatively smooth surface of the used HA particles. For the non-sintered HA (HAns) composites, it was possible to improve significantly both the stiffness and the strength. Amino silanes demonstrated to be highly efficient concerning strength enhancement. The higher effectiveness of the coupling treatments for HAns filled composites is attributed to their higher particle surface area, smaller particle size distribution and expected higher chemical reactivity. For both cases, the improvement in mechanical performance after the coupling treatment is consistent with the enhancement in interfacial adhesion observed by SEM.

  4. Mechanical and biological properties of the micro-/nano-grain functionally graded hydroxyapatite bioceramics for bone tissue engineering.

    PubMed

    Zhou, Changchun; Deng, Congying; Chen, Xuening; Zhao, Xiufen; Chen, Ying; Fan, Yujiang; Zhang, Xingdong

    2015-08-01

    Functionally graded materials (FGM) open the promising approach for bone tissue repair. In this study, a novel functionally graded hydroxyapatite (HA) bioceramic with micrograin and nanograin structure was fabricated. Its mechanical properties were tailored by composition of micrograin and nanograin. The dynamic mechanical analysis (DMA) indicated that the graded HA ceramics had similar mechanical property compared to natural bones. Their cytocompatibility was evaluated via fluorescent microscopy and MTT colorimetric assay. The viability and proliferation of rabbit bone marrow mesenchymal stem cells (BMSCs) on ceramics indicated that this functionally graded HA ceramic had better cytocompatibility than conventional HA ceramic. This study demonstrated that functionally graded HA ceramics create suitable structures to satisfy both the mechanical and biological requirements of bone tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Synthesis, characterization and biological evaluation of strontium/magnesium-co-substituted hydroxyapatite.

    PubMed

    Geng, Zhen; Wang, Renfeng; Li, Zhaoyang; Cui, Zhenduo; Zhu, Shengli; Liang, Yanqin; Liu, Yunde; Huijing, Bao; Li, Xue; Huo, Qianyu; Liu, Zhili; Yang, Xianjin

    2016-07-01

    The present study aims to investigate the contribution of two biologically important cations, Mg(2+) and Sr(2+), when co-substituted into the structure of hydroxyapatite (Ca10(PO4)6(OH)2, HA). The substituted samples were synthesized by a hydrothermal method that involved the addition of Mg(2+) and Sr(2+) containing precursors to partially replace Ca(2+) in the apatite structure. Four co-substituted HA samples with different concentrations of Mg(2+) and Sr(2+) ((Mg + Sr)/(Mg + Sr + Ca) = 30%) were investigated, and they were compared with pure HA. Experimental results showed that only a limited amount of Mg (Mg/(Mg + Ca + Sr) < 14%) could successfully substitute for Ca in HA. In addition, Mg substitution resulted in reduced crystallinity, thermal stability and lattice parameters of HA. In contrast, Sr could fully substitute for Ca. Furthermore, the addition of Sr increased the lattice parameters of HA. Here, we obtained the cation leach liquor by immersing the prepared samples in a culture medium for cell experiments. The in vitro study showed that 10Mg20Sr promoted better MG63 cell attachment, proliferation and differentiation than HA. Thus, the presence of an appropriate proportion of Mg and Sr could play a significant role in the increased biocompatibility of HA. © The Author(s) 2016.

  6. Mechanical parameters of strontium doped hydroxyapatite sintered using microwave and conventional methods.

    PubMed

    Curran, Declan J; Fleming, Thomas J; Towler, Mark R; Hampshire, Stuart

    2011-11-01

    The effects of ion substitution in hydroxyapatite (HA) on crystal structure and lattice stability is investigated in the green state and post sintering. The effects of ion incorporation on the biaxial flexural strength and hardness are also investigated. Sintering is carried out at 1200 °C using comparative conventional and microwave regimes. Post sintering, the effects of ion incorporation manifest as an increase in the lattice d-spacings and a reduction of the crystallite size. Some HA decomposition occurs with β-TCP stabilisation in conventional sintering (CS), but this phase is destabilised during microwave sintering (MS), generating α-TCP. Conventional sintering (CS) allows higher densification in the undoped samples. Overall, for the Sr-doped compositions, the MS samples retain higher amounts of HA and experience higher density levels compared to the CS samples. Published by Elsevier Ltd.

  7. The effects of hydroxyapatite coating and bone allograft on fixation of loaded experimental primary and revision implants.

    PubMed

    Søballe, Kjeld; Mouzin, Olivier R G; Kidder, Louis A; Overgaard, Søren; Bechtold, Joan E

    2003-06-01

    We used our established experimental model of revision joint replacement to examine the roles of hydroxyapatite coating and bone graft in improving the fixation of revision implants. The revision protocol uses the Søballe micromotion device in a preliminary 8-week period of implant instability for the presence of particulate polyethylene. During this procedure, a sclerotic endosteal bone rim forms, and a dense fibrous membrane is engendered, having macrophages with ingested polyethylene and high levels of inflammatory cytokines. At the time of revision after 8 weeks, the cavity is revised with either a titanium alloy (Ti) or a hydroxyapatite (HA) 6.0 mm plasma-sprayed implant, in the presence or absence of allograft packed into the initial 0.75 mm peri-implant gap. The contralateral limb is subjected to primary surgery with the same implant configuration, and serves as control. 8 implants were included in each of the 8 treatment groups (total 64 implants in 32 dogs). The observation period was 4 weeks after revision. Outcome measures are based on histomorphometry and mechanical pushout properties. The revision setting was always inferior to its primary counterpart. Bone graft improved the revision fixation in all treatment groups, as also did the HA coating. The sole exception was revision-grafted HA implants, which reached the same fixation as primary Ti and HA grafted implants. The revision, which was less active in general, seems to need the dual stimulation of bone graft and HA implant surface, to obtain the same level of fixation associated with primary implants. Our findings suggest that the combination of HA implant and bone graft may be of benefit in the clinical revision implant setting.

  8. The effects of hydroxyapatite coating and bone allograft on fixation of loaded experimental primary and revision implants

    PubMed Central

    Søballe, Kjeld; Mouzin, Olivier R G; Kidder, Louis A; Overgaard, Søren; Bechtold, Joan E

    2015-01-01

    We used our established experimental model of revision joint replacement to examine the roles of hydroxyapatite coating and bone graft in improving the fixation of revision implants. The revision protocol uses the Søballe micromotion device in a preliminary 8-week period of implant instability for the presence of particulate polyethylene. During this procedure, a sclerotic endosteal bone rim forms, and a dense fibrous membrane is engendered, having macrophages with ingested polyethylene and high levels of inflammatory cytokines. At the time of revision after 8 weeks, the cavity is revised with either a titanium alloy (Ti) or a hydroxyapatite (HA) 6.0 mm plasma-sprayed implant, in the presence or absence of allograft packed into the initial 0.75 mm peri-implant gap. The contralateral limb is subjected to primary surgery with the same implant configuration, and serves as control. 8 implants were included in each of the 8 treatment groups (total 64 implants in 32 dogs). The observation period was 4 weeks after revision. Outcome measures are based on histomorphometry and mechanical pushout properties. The revision setting was always inferior to its primary counterpart. Bone graft improved the revision fixation in all treatment groups, as also did the HA coating. The sole exception was revision-grafted HA implants, which reached the same fixation as primary Ti and HA grafted implants. The revision, which was less active in general, seems to need the dual stimulation of bone graft and HA implant surface, to obtain the same level of fixation associated with primary implants. Our findings suggest that the combination of HA implant and bone graft may be of benefit in the clinical revision implant setting. PMID:12899541

  9. Does hydroxyapatite coating have no advantage over porous coating in primary total hip arthroplasty? A meta-analysis.

    PubMed

    Chen, Yun-Lin; Lin, Tiao; Liu, An; Shi, Ming-Min; Hu, Bin; Shi, Zhong-Li; Yan, Shi-Gui

    2015-01-28

    There are some arguments between the use of hydroxyapatite and porous coating. Some studies have shown that there is no difference between these two coatings in total hip arthroplasty (THA), while several other studies have shown that hydroxyapatite has advantages over the porous one. We have collected the studies in Pubmed, MEDLINE, EMBASE, and the Cochrane library from the earliest possible years to present, with the search strategy of "(HA OR hydroxyapatite) AND ((total hip arthroplasty) OR (total hip replacement)) AND (RCT* OR randomiz* OR control* OR compar* OR trial*)". The randomized controlled trials and comparative observation trials that evaluated the clinical and radiographic effects between hydroxyapatite coating and porous coating were included. Our main outcome measurements were Harris hip score (HHS) and survival, while the secondary outcome measurements were osteolysis, radiolucent lines, and polyethylene wear. Twelve RCTs and 9 comparative observation trials were included. Hydroxyapatite coating could improve the HHS (p < 0.01), reduce the incidence of thigh pain (p = 0.01), and reduce the incidence of femoral osteolysis (p = 0.01), but hydroxyapatite coating had no advantages on survival (p = 0.32), polyethylene wear (p = 0.08), and radiolucent lines (p = 0.78). Hydroxyapatite coating has shown to have an advantage over porous coating. The HHS and survival was duration-dependent-if given the sufficient duration of follow-up, hydroxyapatite coating would be better than porous coating for the survival. The properties of hydroxyapatite and the implant design had influence on thigh pain incidence, femoral osteolysis, and polyethylene wear. Thickness of 50 to 80 μm and purity larger than 90% increased the thigh pain incidence. Anatomic design had less polyethylene wear.

  10. Injectable Microsphere Gel Progressively Improves Global Ventricular Function, Regional Contractile Strain, and Mitral Regurgitation after Myocardial Infarction

    PubMed Central

    McGarvey, Jeremy R; Kondo, Norihiro; Witschey, Walter RT; Takebe, Manabu; Aoki, Chikashi; Burdick, Jason A.; Spinale, Francis G; Gorman, Joseph H; Pilla, James J; Gorman, Robert C

    2014-01-01

    Background There is continued need for therapies which reverse or abate the remodeling process following myocardial infarction (MI). In this study, we evaluate the longitudinal effects of calcium hydroxyapatite microsphere gel on regional strain, global ventricular function, and mitral regurgitation (MR) in a porcine MI model. Methods Twenty five Yorkshire swine were enrolled. Five were dedicated weight-matched controls. Twenty underwent posterolateral infarction by direct ligation of the circumflex artery and its branches. Infarcted animals were randomly divided into four groups: one week treatment, one week control, four week treatment, and four week control. Following infarction, animals received either twenty 150μl calcium hydroxyapatite gel or saline injections within the infarct. At their respective timepoints, echocardiograms, cardiac MRI, and tissue were collected for evaluation of MR, regional and global left ventricular function, wall thickness, and collagen content. Results Global and regional LV function were depressed in all infarcted subjects at one week compared to healthy controls. By four weeks post-infarction, global function had significantly improved in the calcium hydroxyapatite group compared to infarcted controls (EF 48.5±1.9% vs. 38.0±1.7%, p<0.01). Similarly, regional borderzone radial contractile strain (16.3±1.5% vs. 11.2±1.5%, p=0.04), MR grade (0.4±0.2 vs. 1.2±0.2, p=0.04), and infarct thickness (7.8±0.5mm vs. 4.5±0.2mm, p<0.01) were improved at this timepoint in the treatment group compared to infarct controls. Conclusions Calcium hydroxyapatite injection following MI progressively improves global LV function, borderzone function, and mitral regurgitation. Using novel biomaterials to augment infarct material properties is viable alternative in the current management of heart failure. PMID:25524397

  11. Preparation and characterization of NiW-nHA composite catalyst for hydrocracking

    NASA Astrophysics Data System (ADS)

    Zhou, Gang; Hou, Yongzhao; Liu, Lei; Liu, Hongru; Liu, Can; Liu, Jing; Qiao, Huiting; Liu, Wenyong; Fan, Yubo; Shen, Shituan; Rong, Long

    2012-11-01

    The synthesis, characterization and catalytic capability of the NiW-nano-hydroxyapatite (NiW-nHA) composite were investigated in this paper. The NiW-nHA catalyst was prepared by a co-precipitation method. Then Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX) were used to analyze this material. In addition, the catalytic capacity of the NiW-nHA composite was also examined by FT-IR and gas chromatography (GC). The results of FT-IR analysis indicated that Ni, W and nHA combined closely. TEM observation revealed that this catalyst was needle shaped and the crystal retained a nanometer size. XRD data also suggested that a new phase of CaWO4 appeared and the lattice parameters of nHA changed in this system. nHA was the carrier of metals. The rates of Ni/W-loading were 73.24% and 65.99% according to the EDX data, respectively. Furthermore, the conversion of 91.88% Jatropha oil was achieved at 360 °C and 3 MPa h-1 over NiW-nHA catalyst. The straight chain alkanes ranging from C15 to C18 were the main components in the production. The yield of C15-C18 alkanes was up to 83.56 wt%. The reaction pathway involved hydrocracking of the C&z.dbd;C bonds of these triglycerides from Jatropha oil. This paper developed a novel non-sulfided catalyst to obtain a ``green biofuel'' from vegetable oil.

  12. In vitro biomechanical and biocompatible evaluation of natural hydroxyapatite/chitosan composite for bone repair.

    PubMed

    Lü, Xiaoying; Zheng, Buzhong; Tang, Xiaojun; Zhao, Lifeng; Lu, Jieyan; Zhang, Zhiwei; Zhang, Jizhong; Cui, Wei

    2011-01-01

    To evaluate the biomechanical properties and biocompatibility of natural hydroxyapatite/chitosan (HA/CS) composites. The natural HA/CS composites with a different proportion of HA and CS were prepared by the cross-linking method, and then the compressive strength, microstructure and pH values of extracts from these composites were measured by SEM and pH meter, respectively. Subsequently, the biocompatibility of the composites was evaluated by means of a series of biological tests, including MTT, acute systemic toxicity, heat source, and hemolysis tests in vitro. The chitosan content in the composites had significantly influenced the mechanical properties and microstructure of the composites. The pH value of the composite extract was approximately 7.0, which was very close to that of human plasma. Furthermore, the natural HA/CS composites showed no cytotoxicity, irritation, teratogenicity, carcinogenicity and special pyrogen. These results indicated that the natural HA/CS composite may be a potential bone repair material.

  13. Size controlled hydroxyapatite and calcium carbonate particles: synthesis and their application as templates for SERS platform.

    PubMed

    Parakhonskiy, B V; Svenskaya, Yu I; Yashchenok, A М; Fattah, H A; Inozemtseva, O A; Tessarolo, F; Antolini, R; Gorin, D A

    2014-06-01

    An elegant route for hydroxyapatite (HA) particle synthesis via ionic exchange reaction is reported. Calcium carbonate particles (CaCO3) were recrystallized into HA beads in water solution with phosphate ions. The size of initial CaCO3 particles was controlled upon the synthesis by varying the amount of ethylene glycol (EG) in aqueous solution. The average size of HA beads ranged from 0.6±0.1 to 4.3±1.1μm. Silver nanoparticles were deposited on the surface of HA and CaCO3 particles via silver mirror reaction. Surface enhanced Raman scattering of silver functionalized beads was demonstrated by detecting Rhodamine B. CaCO3 and HA particles have a great potential for design of carrier which can provide diagnostic and therapeutic functions. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Preparation of foam-like carbon nanotubes/hydroxyapatite composite scaffolds with superparamagnetic properties

    NASA Astrophysics Data System (ADS)

    Lu, X. Y.; Qiu, T.; Wang, X. F.; Zhang, M.; Gao, X. L.; Li, R. X.; Lu, X.; Weng, J.

    2012-12-01

    In this paper, the foam-like composite scaffolds composed of hydroxyapatite (HA) and carbon nanotubes (CNTs) were prepared by a new method, where a polymer impregnating method was used for porous HA-based scaffold and a chemical vapor deposition (CVD) method was used for the growth of CNTs from the HA-based scaffold. The process produces the CNTs/HA scaffolds that have a foam-like structure with better mechanical property, better microstructure and a high degree of interconnection. A favorable pore size with big pores of 1-2 mm and small pores of 20-300 μm for osteoconduction and bone ingrowth is presented in these scaffolds. About 2 wt% multi-walled CNTs with the diameter of 60-100 nm are observed to be in situ grown from deficient nano-HA crystallites. Magnetic measurement exhibits these scaffolds are superparamagnetic with a saturation magnetization of 1.14 emu g-1 at a room temperature, benefiting the scaffolds to take up growth factors in vivo, stem cell or other bioactive molecules easily. This new type of CNTs/HA scaffolds is expected to have a promising applications in bone tissue engineering, targeted drug delivery system and other biomedical fields.

  15. Characterisation and sintering of nanophase hydroxyapatite synthesised by a species of Serratia

    NASA Astrophysics Data System (ADS)

    LSammons, R.; Thackray, A. C.; Medina Ledo, H.; Marquis, P. M.; Jones, I. P.; Yong, P.; Macaskie, L. E.

    2007-12-01

    The bacterium Serratia sp. NCIMB40259, which grows as a biofilm on polymeric, glass and metal substrates, produces extracellular crystals of hydroxyapatite (HA) by enzymatic cleavage of β-glycerophosphate in the presence of calcium chloride. Following growth on polyurethane foam, biomineralisation and subsequent sintering, an HA scaffold is formed whose three-dimensional architecture replicates that of the foam and the biofilm. Serratia HA was characterised using X-ray diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR), energy dispersive X-ray analysis (EDX) scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron diffraction (ED). The nascent, unsintered material consisted mainly of calcium-deficient HA (CDHA) with a Ca/P ratio of 1.61+/- 0.06 and crystal size (TEM) of 50 +/- 10nm length. ED of unsintered crystals and crystals sintered at 600° C showed resolvable ring (unsintered) or dot (600° C) patterns ascribed to (0002), (1122) and (0006) planes of crystalline HA. Material sintered at 1200° C consisted of needle-like crystals of length range 54-111nm (XRD) with lattice parameters of a = 9.441 Å and c = 6.875 Å, consistent with HA.

  16. Enhanced Photocatalytic Activity of TiO2 Nanoparticles Supported on Electrically Polarized Hydroxyapatite.

    PubMed

    Zhang, Xuefei; Yates, Matthew Z

    2018-05-23

    Fast recombination of photogenerated charge carriers in titanium dioxide (TiO 2 ) remains a challenging issue, limiting the photocatalytic activity. This study demonstrates increased photocatalytic performance of TiO 2 nanoparticles supported on electrically polarized hydroxyapatite (HA) films. Dense and thermally stable yttrium and fluorine co-doped HA films with giant internal polarization were synthesized as photocatalyst supports. TiO 2 nanoparticles deposited on the support were then used to catalyze the photochemical reduction of aqueous silver ions to produce silver nanoparticles. It was found that significantly more silver nanoparticles were produced on polarized HA supports than on depolarized HA supports. In addition, the photodegradation of methyl orange with TiO 2 nanoparticles on polarized HA supports was found to be much faster than with TiO 2 nanoparticles on depolarized HA supports. It is proposed that separation of photogenerated electrons and holes in TiO nanoparticles is promoted by the internal polarization of the HA support, and consequently, the recombination of charge carriers is mitigated. The results imply that materials with large internal polarization can be used in strategies for enhancing quantum efficiency of photocatalysts.

  17. Hydroxyapatite promotes superior keratocyte adhesion and proliferation in comparison with current keratoprosthesis skirt materials.

    PubMed

    Mehta, J S; Futter, C E; Sandeman, S R; Faragher, R G A F; Hing, K A; Tanner, K E; Allan, B D S

    2005-10-01

    Published clinical series suggest the osteoodontokeratoprosthesis (OOKP) may have a lower extrusion rate than current synthetic keratoprostheses. The OOKP is anchored in the eye wall by autologous tooth. The authors' aim was to compare adhesion, proliferation, and morphology for telomerase transformed keratocytes seeded on calcium hydroxyapatite (the principal mineral constituent of tooth) and materials used in the anchoring elements of commercially available synthetic keratoprostheses. Test materials were hydroxyapatite, polytetrafluoroethylene (PTFE), polyhydroxyethyl methacrylate (HEMA), and glass (control). Cell adhesion and viability were quantified at 4 hours, 24 hours, and 1 week using a calcein-AM/EthD-1 viability/cytotoxicity assay. Focal contact expression and cytoskeletal organisation were studied at 24 hours by confocal microscopy with immunoflourescent labelling. Further studies of cell morphology were performed using light and scanning electron microscopy. Live cell counts were significantly greater on hydroxyapatite surfaces at each time point (p<0.04). Dead cell counts were significantly higher for PTFE at 7 days (p<0.002). ss(1) integrin expression was highest on hydroxyapatite. Adhesion structures were well expressed in flat, spread out keratocytes on both HA and glass. Keratocytes tended to be thinner and spindle shaped on PTFE. The relatively few keratocytes visible on HEMA test surfaces were rounded and poorly adherent. Keratocyte adhesion, spreading, and viability on hydroxyapatite test surfaces is superior to that seen on PTFE and HEMA. Improving the initial cell adhesion environment in the skirt element of keratoprostheses may enhance tissue integration and reduce device failure rates.

  18. Electric field-assisted sintering of nanocrystalline hydroxyapatite for biomedical applications

    NASA Astrophysics Data System (ADS)

    Tran, Tien Bich

    As the main inorganic component of bone, hydroxyapatite (HA, Ca 10(PO4)6(OH)2) should be an ideal candidate in biomaterials selection. When grain sizes are in the nanometric regime, protein adsorption and cell adhesion are enhanced, while strength, hardness, and wear resistance are improved. Unfortunately, low phase stability, poor sinterability, and a tendency towards exaggerated grain coarsening challenge full densification of nanocrystalline hydroxyapatite by conventional sintering methods. The field-assisted sintering technique (FAST) has successfully consolidated a variety of nanocrystalline metals and ceramics in dramatically reduced times. The sintering enhancements observed during FAST can be attributed to thermal and athermal effects. The rapid heating rates (up to ˜1000ºC/min) afforded by FAST contribute a significant thermal effect. Since fast heating rates reduce powder exposure to sub-sintering temperatures, non-densifying surface diffusion is limited. The athermal effects of FAST are less well understood and can include plasma generation, dielectric breakdown, particle surface cleaning, grain boundary pinning, and space charge effects. Applying the field-assisted sintering technique to nanocrystalline hydroxyapatite yielded surprising results. Deviations from conventional densification behavior were observed, with dehydroxylation identified as the most deleterious process to densification as well as mechanical and biological performance. Since hydroxyapatite is not a stable phase at high temperatures and low water partial pressure atmospheres, desintering due to dehydroxylation-related pore formation became apparent during Stage III sintering. In fact, the degree of desintering and pore formation increased with the extent of Stage III sintering and grain growth. The atomic rearrangements taking place during grain boundary migration are believed to favor the formation of more-stable oxyapatite through hydroxyapatite dehydroxylation. This behavior was

  19. Sectioning studies of biomimetic collagen-hydroxyapatite coatings on Ti-6Al-4V substrates using focused ion beam

    NASA Astrophysics Data System (ADS)

    Hu, Changmin; Yu, Le; Wei, Mei

    2018-06-01

    A biomimetic bone-like collagen-hydroxyapatite (Col-HA) composite coating was formed on a surface-treated Ti-6Al-4V alloy substrate via simultaneous collagen self-assembly and hydroxyapatite nucleation. The coating process has been carried out by immersing sand-blasted, acid-etched and UV irradiated Ti-6Al-4V alloy in type I collagen-containing modified simulated body fluid (m-SBF). The surface morphology and phase composition of the coating were characterized using various techniques. More importantly, dual-beam FIB/SEMs with either gallium ion source (GFIB) or xenon plasma ion source (PFIB) were used to investigate the cross-sectional features of the biomimetic Col-HA composite coating in great details. As a result, the cross-sectional images and thin transmission electron microscopy (TEM) specimens were successfully obtained from the composite coating with no obvious damages or milling ion implantations. Both the cross-sectional SEM and TEM results have confirmed that the Col-HA coating demonstrates a similar microstructure to that of pure HA coating with homogeneously distributed elements across the whole cross section. Both coatings consist of a uniform, crack-free gradient structure with a dense layer adjacent to the interface between the Ti-6Al-4V substrate and the coating facilitating a strong bonding, while a porous structure at the coating surface aiding cell attachment.

  20. [Histocompatibility of nano-hydroxyapatite/poly-co-glycolic acid tissue engineering bone modified by mesenchymal stem cells with vascular endothelial frowth factor].

    PubMed

    Zhang, Minglei; Wang, Dapeng; Yin, Ruofeng

    2015-10-06

    To explorec Histocompatibility of nano-hydroxyapatite/poly-co-glycolic acid tissue engineering bone modified by mesenchymal stem cells with vascular endothelial frowth factor transinfected. Rat bone marrow mesenchymal stem cells (BMSCs) was separated, using BMSCs as target cells, and then vascular endothelial growth factor (VEGF) gene was transfected. Composite bone marrow mesenchymal stem cells and cells transfected with nano-hydroxyapatite (HA)/polylactic-co-glycolic acid (PLGA). The composition of cell and scaffold was observed. The blank plasmid transfection was 39.1%, 40.1% in VEGF group. The cell adhesion and growth was found on the scaffold pore wall after 5 days, and the number of adherent cells in the nano-HA/PLGA composite scaffold material basically had no significant difference in both. Although the nano-HA/PLGA scaffold material is still not fully meet the requirements of the matrix material for bone tissue engineering, but good biocompatibility, structure is its rich microporous satisfaction in material mechanics, toughening, enhanced obviously. Composition scaffold with BMSCs transfected by VEGF plasmid, the ability of angiogenesis is promoted.

  1. The efficacy of porous hydroxyapatite bone chip as an extender of local bone graft in posterior lumbar interbody fusion.

    PubMed

    Kim, Hyoungmin; Lee, Choon-Ki; Yeom, Jin-Sup; Lee, Jae-Hyup; Lee, Ki-Ho; Chang, Bong-Soon

    2012-07-01

    To evaluate whether a synthetic bone chip made of porous hydroxyapatite can effectively extend local decompressed bone graft in instrumented posterior lumbar interbody fusion (PLIF). 130 patients, 165 segments, who had undergone PLIF with cages and instrumentation for single or double level due to degenerative conditions, were investigated retrospectively by independent blinded observer. According to the material of graft, patients were divided into three groups. HA group (19 patients, 25 segments): with hydroxyapatite bone chip in addition to autologous local decompressed bone, IBG group (25 patients, 28 segments): with autologous iliac crest bone graft in addition to local decompressed bone and LB group (86 patients, 112 segments): with local decompressed bone only. Radiologic and clinical outcome were compared among groups and postoperative complications, transfusion, time and cost of operation and duration of hospitalization were also investigated. Radiologic fusion rate and clinical outcome were not different. Economic cost, transfusion and hospital stay were also similar. But operation time was significantly longer in IBG group than in other groups. There were no lasting complications associated with HA and LB group with contrast to five cases with persisting donor site pain in IBG group. Porous hydroxyapatite bone chip is a useful bone graft extender in PLIF when used in conjunction with local decompressed bone.

  2. Microspheres and their methods of preparation

    DOEpatents

    Bose, Anima B; Yang, Junbing

    2015-03-24

    Carbon microspheres are doped with boron to enhance the electrical and physical properties of the microspheres. The boron-doped carbon microspheres are formed by a CVD process in which a catalyst, carbon source and boron source are evaporated, heated and deposited onto an inert substrate.

  3. Multi and mixed 3D-printing of graphene-hydroxyapatite hybrid materials for complex tissue engineering.

    PubMed

    Jakus, Adam E; Shah, Ramille N

    2017-01-01

    With the emergence of three-dimensional (3D)-printing (3DP) as a vital tool in tissue engineering and medicine, there is an ever growing need to develop new biomaterials that can be 3D-printed and also emulate the compositional, structural, and functional complexities of human tissues and organs. In this work, we probe the 3D-printable biomaterials spectrum by combining two recently established functional 3D-printable particle-laden biomaterial inks: one that contains hydroxyapatite microspheres (hyperelastic bone, HB) and another that contains graphene nanoflakes (3D-graphene, 3DG). We demonstrate that not only can these distinct, osteogenic, and neurogenic inks be co-3D-printed to create complex, multimaterial constructs, but that composite inks of HB and 3DG can also be synthesized. Specifically, the printability, microstructural, mechanical, electrical, and biological properties of a hybrid material comprised of 1:1 HA:graphene by volume is investigated. The resulting HB-3DG hybrid exhibits mixed characteristics of the two distinct systems, while maintaining 3D-printability, electrical conductivity, and flexibility. In vitro assessment of HB-3DG using mesenchymal stem cells demonstrates the hybrid material supports cell viability and proliferation, as well as significantly upregulates both osteogenic and neurogenic gene expression over 14 days. This work ultimately demonstrates a significant step forward towards being able to 3D-print graded, multicompositional, and multifunctional constructs from hybrid inks for complex composite tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 274-283, 2017. © 2016 Wiley Periodicals, Inc.

  4. Nano-hydroxyapatite particles induce apoptosis on MC3T3-E1 cells and tissue cells in SD rats

    NASA Astrophysics Data System (ADS)

    Wang, Liting; Zhou, Gang; Liu, Haifeng; Niu, Xufeng; Han, Jingyun; Zheng, Lisha; Fan, Yubo

    2012-04-01

    While the advantages of nanomaterials are being increasingly recognized, their potential toxicity is drawing more and more attention and concern. In this study, we explore the toxicity mechanism of 20-30 nm rod-shaped hydroxyapatite (HA) nanoparticles in vitro and in vivo. The nanoparticles were prepared by precipitation and characterized by IR, XRD and TEM. Concentrations of 0 μg mL-1, 10 μg mL-1, 100 μg mL-1, 1 mg mL-1, and 10 mg mL-1 were applied to the MC3T3-E1 cells for viability (MTT-test). Based on the characteristic differences of the two methods of cell death, the morphological features of the MC3T3-E1 cell line co-cultured with nano-hydroxyapatite (n-HA) (10 mg mL-1) for 24 h were also observed by TEM. Furthermore, important serum biochemical markers and histopathological examinations were used to evaluate the potential toxicological effect of n-HA on the major organs of SD rats injected intraperitoneally with n-HA (33.3 mg kg-1 body weight). In the results, we found cell growth inhibition and apoptosis in MC3T3-E1 cells co-cultured with n-HA. Moreover, apoptosis but not necrosis was illustrated in liver and renal tissue by using histopathology slices and serum biochemical markers. It suggests that apoptosis may be the possible mechanism of n-HA toxicity and provides a better understanding of the biocompatibility of nanomaterials applied in human bone repair.

  5. Thermal stability of a modified sol-gel derived hydroxyapatite nanopowders

    NASA Astrophysics Data System (ADS)

    Herradi, S.; El Bali, B.; Khaldi, M.; Lachkar, M.

    2017-03-01

    Hydroxyapatite Ca10(PO4)6(OH)2 (HA) powder was successfully synthesized by a modified sol-gel method using a solution of calcium nitrate in ethanol, along with a solution of diammonium hydrogen phosphate in water and NH4OH as starting materials. The Ca/P molar ratio was maintained at 1.67. The powder was subjected to furnace and microwave heating to compare the decomposition of HA and study the crystallite sizes. It was found that microwave heated powders were pure HAP up to 230°C with absence of secondary phases. However, XRD patterns show that furnace heated powders convert completely to β-TCP when treated at 750°C and 1000°C. This result was confirmed by the absence of hydroxyl bands in the FT-IR spectra for these temperatures.

  6. Poly(vinyl alcohol)/hydroxyapatite Monolithic In-Needle Extraction (MINE) device: Preparation and examination of drug affinity.

    PubMed

    Pietrzyńska, Monika; Czerwiński, Michał; Voelkel, Adam

    2017-07-15

    Polymer-ceramic materials based on poly(vinyl alcohol) (PVA) and hydroxyapatite were applied as sorption material in Monolithic In-Needle Extraction (MINE) device. The presented device provides new possibilities for the examination of bisphosphonates affinity for bone and will be a helpful tool in evaluation of potential antiresorptive drugs suitability. A ceramic part of monoliths was prepared by incorporation of hydroxyapatite (HA) into the reaction mixture or by using a soaking method (mineralization of HA on the PVA). The parameters of synthesis conditions were optimized to achieve a monolithic material having the appropriate dimensions after the soaking process enabling placing of the monolithic material inside the needle. Furthermore, the material must have had optimal dimensions after the re-soaking process to fit perfectly to the needle. Among the sixteen monolithic materials, eight of them were selected for further study, and then four of them were selected as a sorbent material for the MINE device. The material properties were examined on the basis of several parameters: swelling ratio, initial mass reversion and initial diameter reversion, mass growth due to the HA formation, and antiresorptive drug sorption. The MINE device might be then used as a tool for examination of interactions between bisphosphonate and bone. The simulated body fluid containing sodium risedronate (RSD) as a standard compound was passed through the MINE device. The obtained device allowed for sorption about 0.38mg of RSD. The desorption process was carried out in five steps allowing insightful analysis. The MINE device turned out to be a helpful tool for determination of the bisphosphonates affinity to the ceramic part of sorbent (hydroxyapatite) and to assess the usefulness of them as antiresorptive drugs in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Preparation and Properties of Nano-Hydroxyapatite/Gelatin/Poly(vinyl alcohol) Composite Membrane.

    PubMed

    Liao, Haotian; Shi, Kun; Peng, Jinrong; Qu, Ying; Liao, Jinfeng; Qian, Zhiyong

    2015-06-01

    In this study, the bone-like composite membrane based on blends of gelatin (Gel), nano-hydroxyapatite (n-HA) and poly(vinyl alcohol) (PVA) was fabricated by solvent casting and evaporation methods. The effect of n-HA content and the ratio of Gel/PVA on the properties of the composite was investigated. The Gel/PVA and n-HA/Gel/PVA composite membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), water contact angle measurement and scanning electron microscopy (SEM). The mechanical properties of the composites were determined by tensile tests. The as prepared composite membranes exhibited hydrophobility, the water contact angle of composite membrane was 126.6 when its mass ratio of n-HA/Gel/PVA was 10/50/40. The tensile strength of composite membranes was greatly increased due to the introduction of n-HA, and the tensile strength was increased to 74.92 MPa when the mass ratio of n-HA/Gel/PVA was 10/50/40. SEM observation indicated that n-HA was dispersed in the membranes and a sea-island structure was formed in the n-HA/Gel/PVA composite membranes, resulting in a significant increase in tensile strength. The as-prepared n-HA/Gel/PVA composite membranes may be applied in the field of bone tissue engineering.

  8. Nano-hydroxyapatite-coated metal-ceramic composite of iron-tricalcium phosphate: Improving the surface wettability, adhesion and proliferation of mesenchymal stem cells in vitro.

    PubMed

    Surmeneva, Maria A; Kleinhans, Claudia; Vacun, Gabriele; Kluger, Petra Juliane; Schönhaar, Veronika; Müller, Michaela; Hein, Sebastian Boris; Wittmar, Alexandra; Ulbricht, Mathias; Prymak, Oleg; Oehr, Christian; Surmenev, Roman A

    2015-11-01

    Thin radio-frequency magnetron sputter deposited nano-hydroxyapatite (HA) films were prepared on the surface of a Fe-tricalcium phosphate (Fe-TCP) bioceramic composite, which was obtained using a conventional powder injection moulding technique. The obtained nano-hydroxyapatite coated Fe-TCP biocomposites (nano-HA-Fe-TCP) were studied with respect to their chemical and phase composition, surface morphology, water contact angle, surface free energy and hysteresis. The deposition process resulted in a homogeneous, single-phase HA coating. The ability of the surface to support adhesion and the proliferation of human mesenchymal stem cells (hMSCs) was studied using biological short-term tests in vitro. The surface of the uncoated Fe-TCP bioceramic composite showed an initial cell attachment after 24h of seeding, but adhesion, proliferation and growth did not persist during 14 days of culture. However, the HA-Fe-TCP surfaces allowed cell adhesion, and proliferation during 14 days. The deposition of the nano-HA films on the Fe-TCP surface resulted in higher surface energy, improved hydrophilicity and biocompatibility compared with the surface of the uncoated Fe-TCP. Furthermore, it is suggested that an increase in the polar component of the surface energy was responsible for the enhanced cell adhesion and proliferation in the case of the nano-HA-Fe-TCP biocomposites. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Nano-functionalization of protein microspheres

    NASA Astrophysics Data System (ADS)

    Yoon, Sungkwon; Nichols, William T.

    2014-08-01

    Protein microspheres are promising building blocks for the assembly of complex functional materials. Here we demonstrate a set of three techniques that add functionality to the surface of protein microspheres. In the first technique, a positive surface charge on the protein spheres is deposited by electrostatic adsorption. Negatively charged silica and gold nanoparticle colloids can then electrostatically bind reversibly to the microsphere surface. In the second technique, nanoparticles are covalently anchored to the protein shell using a simple one-pot process. The strong covalent bond between sulfur groups in cysteine in the protein shell irreversibly binds to the gold nanoparticles. In the third technique, surface morphology of the protein microsphere is tuned through hydrodynamic instability at the water-oil interface. This is accomplished through the degree of solubility of the oil phase in water. Taken together these three techniques form a platform to create nano-functionalized protein microspheres, which can then be used as building blocks for the assembly of more complex macroscopic materials.

  10. Metal containing polymeric functional microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Molday, Robert S. (Inventor)

    1979-01-01

    Polymeric functional microspheres containing metal or metal compounds are formed by addition polymerization of a covalently bondable olefinic monomer such as hydroxyethylmethacrylate in the presence of finely divided metal or metal oxide particles, such as iron, gold, platinum or magnetite, which are embedded in the resulting microspheres. The microspheres can be covalently bonded to chemotherapeutic agents, antibodies, or other proteins providing a means for labeling or separating labeled cells. Labeled cells or microspheres can be concentrated at a specific body location such as in the vicinity of a malignant tumor by applying a magnetic field to the location and then introducing the magnetically attractable microspheres or cells into the circulatory system of the subject. Labeled cells can be separated from a cell mixture by applying a predetermined magnetic field to a tube in which the mixture is flowing. After collection of the labeled cells, the magnetic field is discontinued and the labeled sub-cell population recovered.

  11. Involvement of Rho kinase in the pathogenesis of acute pulmonary embolism-induced polystyrene microspheres in rats.

    PubMed

    Toba, M; Nagaoka, T; Morio, Y; Sato, K; Uchida, K; Homma, N; Takahashi, K

    2010-03-01

    Acute pulmonary embolism (PE) is a life-threatening disease, and several vasoconstrictors, including endothelin-1 (ET-1), play a key role in vasoconstriction and hypoxemia during the development of PE. Rho kinase is activated by various vasoconstrictors resulting in vascular contraction and remodeling. Recent evidence has revealed an important role of Rho kinase in the pathogenesis of systemic and pulmonary vascular diseases. However, contribution of Rho kinase in PE remains unclear. We thus investigated the role of Rho kinase in the PE rat model induced by intrajugular administration of polystyrene microspheres (mean diameter, 26 microm). At 6 h following the administration of microspheres (1.5 ml/kg), right ventricular systolic pressure (RVSP) was higher in the PE than in the control rats (15.8 +/- 1.6 vs. 32.9 +/- 7.5 mmHg). Arterial oxygen tension was lower (92.3 +/- 12.5 vs. 66.0 +/- 17.7 Torr), and alveolar-arterial difference in oxygen partial pressure was higher (3.9 +/- 3.8 vs. 36.5 +/- 26.9 Torr) in the PE rats. Western blotting analysis revealed upregulation and downregulation in expression of vascular cell adhesion molecule-1 and endothelial nitric oxide synthase in lungs from the PE rats, respectively, and radioimmunoassay demonstrated an increase in plasma ET-1 levels. Lung Rho kinase alpha expression was greater in the PE rats. At 5 h following administration of microspheres (0.75 ml/kg), intravenous Rho kinase inhibitors HA1077 and Y27632 (3 mg/kg each) attenuated elevation of RVSP (22.0 +/- 3.7, 17.1 +/- 3.2, 14.3 +/- 2.6 mmHg, PE, PE+HA1077, PE+Y27632) and the severity of hypoxemia (66.3 +/- 16.2, 94.9 +/- 23.0, 89.1 +/- 8.5 Torr, PE, PE+HA1077, PE+Y27632) in the PE rats. These results suggest that pulmonary endothelial dysfunction and activation of Rho kinase may contribute to the potentiation of vasoconstriction and hypoxemia in the PE rats.

  12. Synthesis and characterization of hydroxyapatite nanoparticles by chemical precipitation method for potential application in water treatment

    NASA Astrophysics Data System (ADS)

    Joshi, Parth; Patel, Chirag; Vyas, Meet

    2018-05-01

    Hydroxyapatite (HA) is a unique material having high adsorption capacity of heavy metals, high ion exchange capacity, high biological compatibility, low water solubility, high stability under reducing and oxidizing conditions, availability and low cost. As the starting reagents, analytical grade Ca(NO3)2.4H2O, (NH4)2HPO4 and NaOH were used. In order to study the factors that have an important influence on the chemical precipitation process a experimental platform has been designed for hydroxyapatite synthesis. The addition of Phosphorus pentaoxide to Calcium hydroxide was carried out slowly with simultaneous stirring. After addition, solution was aged for maturation. The precipitate was dried at 80°C overnight and further heat treated at 600°C for 2 hours. The dried and calcined particles were characterized by Fourier transform infra-red spectroscopy and Thermo gravimetric analysis. The particle size and morphology were studied using transmission electron microscopy. TEM examination of the treated powders displayed particles of polygon morphology with dimensions 30-70 nm in length. The FT-IR spectra for sample confirmed the formation of hydroxyapatite. Purity of the prepared Hydroxyapatite has been confirmed by XRD analysis.

  13. Morphological structure and characteristics of hydroxyapatite/β-cyclodextrin composite nanoparticles synthesized at different conditions.

    PubMed

    Son, Kyoung Dan; Kim, Young-Jin

    2013-01-01

    Hydroxyapatite (HA) nanoparticles were prepared simply in the presence of β-cyclodextrin (β-CD). Mixing sequence of ion precursors during the synthesis of HA greatly affected the morphological structure of nanoparticles. Ca-P showed only the sphere-like structure, however P-Ca exhibited the mixture of spherical and rod-like nanoparticles. The size of nanoparticles slightly decreased with increasing the content of β-CD. The HAs synthesized in the presence of β-CD agglomerated, leading to the formation of aggregates with a size of hundreds nanometer and narrow size distribution. FT-IR, XRD and XRF analyses confirmed that the HA nanoparticles could be synthesized with using β-CD, in which the Ca/P molar ratio was ranged from 1.72 to 1.70. The crystalline phase of these HA nanoparticles was similar to that of the stoichiometric HA. In addition, the content of β-CD contained in the products could influence the initial deposition rate of bone-like apatite on the surface of HA nanoparticles in simulated body fluid (SBF). Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Facile synthesis of both needle-like and spherical hydroxyapatite nanoparticles: effect of synthetic temperature and calcination on morphology, crystallite size and crystallinity.

    PubMed

    Wijesinghe, W P S L; Mantilaka, M M M G P G; Premalal, E V A; Herath, H M T U; Mahalingam, S; Edirisinghe, M; Rajapakse, R P V J; Rajapakse, R M G

    2014-09-01

    Synthetic hydroxyapatite (HA) nanoparticles, that mimic natural HA, are widely used as biocompatible coatings on prostheses to repair and substitute human bones. In this study, HA nanoparticles are prepared by precipitating them from a precursor solution containing calcium sucrate and ammonium dihydrogen orthophosphate, at a Ca/P mole ratio of 1.67:1, at temperatures, ranging from 10°C to 95°C. A set of products, prepared at different temperatures, is analyzed for their crystallinity, crystallite size, morphology, thermal stability and composition, by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopic techniques, while the other set is analyzed after calcining the respective products, soon after their synthesis, for 3h, at 700°C. The as-prepared products, after 2h of drying, without any calcination, are not crystalline, but they grow very slowly into needle-like morphologies, as they are ripened with time. The percentage crystallinity of the final products increases from 15% to 52%, with increasing the preparative temperature. The calcined samples always produce spherical nanoparticles of essentially the same diameter, between 90 nm and 100 nm, which does not change due to aging and preparative temperatures. Therefore, the same method can be utilized to synthesize both spherical and needle-like nanoparticles of hydroxyapatite, with well-defined sizes and shapes. The ability to use readily available cheap raw materials, for the synthesis of such well-defined crystallites of hydroxyapatite, is an added advantage of this method, which may be explored further for the scaling up of the procedures to suit to industrial scale synthesis of such hydroxyapatite nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Effect of silver additive on physicochemical properties of hydroxyapatite applied to reconstructive surgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhuk, I. V., E-mail: zhukiv1993@mail.ru; Rasskazova, L. A., E-mail: ly-2207@mail.ru; Korotchenko, N. M., E-mail: korotch@mail.ru

    The effect of silver adding to hydroxyapatite (HA) in its solubility in physiological solution and biological activity was investigated. Samples of HA containing silver (AgHA) obtained by liquid-phase method in the conditions of microwave exposure. Solubility (C{sub Ca}{sup 2+}·10{sup 3}, mol/l) of the powders AgHA was determined by chemical methods according trilonometric titration of the calcium ions in physiological solution at 25 and 37 °C. To investigate the biological activity of the samples, a series of experiments on the formation of the calcium-phosphate layer on the surface of the SBF-solution at 37 °C for 28 days. Electronic micrographs of samplesmore » taken at the end of each 7 days of the experiment, indicate the formation of calcium-phosphate layer (CPL) in the samples, the kinetics of which is shown as a function of cumulative concentrations of calcium and magnesium ions from time.« less

  16. Adsorption and spectroscopic characterization of lactoferrin on hydroxyapatite nanocrystals.

    PubMed

    Iafisco, Michele; Di Foggia, Michele; Bonora, Sergio; Prat, Maria; Roveri, Norberto

    2011-01-28

    Lactoferrin (LF), a well-characterized protein of blood plasma and milk with antioxidant, cariostatic, anticarcinogenic and anti-inflammatory properties, has been adsorbed onto biomimetic hydroxyapatite (HA) nanocrystals at two different pH values (7.4 and 9.0). The interaction was herein investigated by spectroscopic, thermal and microscopic techniques. The positive electrostatic surface potential of LF at pH 7.4 allows a strong surface interaction with the slightly negative HA nanocrystals and avoids the protein-protein interaction, leading to the formation of a coating protein monolayer. In contrast, at pH 9.0 the surface potential of LF is a mix of negative and positive zones favouring the protein-protein interaction and reducing the interaction with HA nanocrystals; as a result a double layer of coating protein was formed. These experimental findings are supported by the good fittings of the adsorption isotherms by different theoretical models according to Langmuir, Freundlich and Langmuir-Freundlich models. The nanosized HA does not appreciably affect the conformation of the adsorbed protein. In fact, using FT-Raman and FT-IR, we found that after adsorption the protein was only slightly unfolded with a small fraction of the α-helix structure being converted into turn, while the β-sheet content remained almost unchanged. The bioactive surface of HA functionalized with LF could be utilized to improve the material performance towards the biological environment for biomedical applications.

  17. Preparation and Characterisation of Hydroxyapatite Coatings on Nanotubular TiO2 Surface Obtained by Sol-Gel Process.

    PubMed

    Shin, Jin-Ho; Kim, Jung-Hwa; Koh, Jeong-Tae; Lim, Hyun-Pil; Oh, Gye-Jeong; Lee, Seok-Woo; Lee, Kwang-Min; Yun, Kwi-Dug; Park, Sang-Won

    2015-08-01

    Hydroxyapatite (HA) coating on titanium dioxide (TiO2) nanotubular surface has been developed to complement the defects of both TiO2 and HA. A sol-gel processing technique was used to coat HA on TiO2 nanotubular surface. All the titanium discs were blasted with resorbable blast media (RBM). RBM-blasted Ti surface, anodized Ti surface, and sol-gel HA coating on the anodized Ti surface were prepared. The characteristics of samples were observed using scanning electron microscopy and X-ray photoemission spectroscopy. Biologic responses were evaluated with human osteosarcoma MG63 cells in vitro. The top of the TiO2 nanotubes was not completely covered by HA particles when the coating time was less than 60 sec. It was demonstrated the sol-gel derived HA film was well-crystallized and this enhanced biologic responses in early stage cell response.

  18. Rapid Obtaining of Nano-Hydroxyapatite Bioactive Films on NiTi Shape Memory Alloy by Electrodeposition Process

    NASA Astrophysics Data System (ADS)

    Lobo, A. O.; Otubo, J.; Matsushima, J. T.; Corat, E. J.

    2011-07-01

    Nano-hydroxyapatite (n-HA) crystalline films have been developed in this study by electrodeposition method on NiTi shape memory alloy (SMA). The electrodeposition of the n-HA films was carried out using 0.042 mol/L Ca(NO3)2 · 4H2O + 0.025 mol/L (NH4) · 2HPO4 electrolytes by applying a constant potential of -2.0 V for 120 min and keeping the solution temperature at 70 °C. The characterization of n-HA films is of special importance since bioactive properties related to n-HA have been directly identified with its specific composition and crystalline structure. AFM, XRD, EDX, FEG-SEM and Raman spectroscopy shows a homogeneous film, with high crystallinity, special composition, and bioactivity properties (Ca/P = 1.93) of n-HA on NiTi SMA surfaces. The n-HA coating with special structure would benefit the use of NiTi alloy in orthopedic applications.

  19. Fabrication and characterization of electrospun cellulose/nano-hydroxyapatite nanofibers for bone tissue engineering.

    PubMed

    Ao, Chenghong; Niu, Yan; Zhang, Ximu; He, Xu; Zhang, Wei; Lu, Canhui

    2017-04-01

    Nanofibrous scaffolds from cotton cellulose and nano-hydroxyapatite (nano-HA) were electrospun for bone tissue engineering. The solution properties of cellulose/nano-HA spinning dopes and their associated electrospinnability were characterized. Morphological, thermal and mechanical properties of the electrospun cellulose/nano-HA nanocomposite nanofibers (ECHNN) were measured and the biocompatibility of ECHNN with human dental follicle cells (HDFCs) was evaluated. Scanning electron microscope (SEM) images indicated that the average diameter of ECHNN increased with a higher nano-HA loading and the fiber diameter distributions were well within the range of natural ECM (extra cellular matrix) fibers (50-500nm). The ECHNN exhibited extraordinary mechanical properties with a tensile strength and a Young's modulus up to 70.6MPa and 3.12GPa respectively. Moreover, it was discovered that the thermostability of the ECHNN could be enhanced with the incorporation of nano-HA. Cell culture experiments demonstrated that the ECHNN scaffolds were quite biocompatible for HDFCs attachment and proliferation, suggesting their great potentials as scaffold materials in bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Electrospinning of calcium carbonate fibers and their conversion to nanocrystalline hydroxyapatite.

    PubMed

    Holopainen, Jani; Santala, Eero; Heikkilä, Mikko; Ritala, Mikko

    2014-12-01

    Calcium carbonate (CaCO3) fibers were prepared by electrospinning followed by annealing. Solutions consisting of calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) and polyvinylpyrrolidone (PVP) dissolved in ethanol or 2-methoxyethanol were used for the fiber preparation. By varying the precursor concentrations in the electrospinning solutions CaCO3 fibers with average diameters from 140 to 290 nm were obtained. After calcination the fibers were identified as calcite by X-ray diffraction (XRD). The calcination process was studied in detail with high temperature X-ray diffraction (HTXRD) and thermogravimetric analysis (TGA). The initially weak fiber-to-substrate adhesion was improved by adding a strengthening CaCO3 layer by spin or dip coating Ca(NO3)2/PVP precursor solution on the CaCO3 fibers followed by annealing of the gel formed inside the fiber layer. The CaCO3 fibers were converted to nanocrystalline hydroxyapatite (HA) fibers by treatment in a dilute phosphate solution. The resulting hydroxyapatite had a plate-like crystal structure with resemblance to bone mineral. The calcium carbonate and hydroxyapatite fibers are interesting materials for bone scaffolds and bioactive coatings. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Collagen/hydroxyapatite composite materials with desired ceramic properties.

    PubMed

    Andronescu, Ecaterina; Voicu, Georgeta; Ficai, Maria; Mohora, Ioana Anita; Trusca, Roxana; Ficai, Anton

    2011-01-01

    Our purpose was to obtain and characterize some collagen/hydroxyapatite (COLL/HA) hybrid composite materials with desired ceramic properties. The ceramic properties of these materials were achieved by combining two drying methods: controlled air drying at 30°C followed by freeze-drying. Through the function of the air drying times, the materials morphology varies from porous materials (when the materials are freeze-dried) up to dense materials (when the materials are air-dried), while the combined drying allows us to obtain an intermediary morphology. The composite materials intended to be used as bone grafts and in a drug delivery system were characterized by XRD, FTIR, SEM, and also by determining the ceramic properties by using the Arthur method. The ceramic properties of these COLL/HA composite materials vary in large range, for instance the density of the materials varies from 0.06 up to 1.5 g/cm(3) while the porosity varies from 96.5% down to 27.5%.

  2. Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

    NASA Astrophysics Data System (ADS)

    Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

    2013-11-01

    Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate.

  3. Silver/hydroxyapatite composite coatings on porous titanium surfaces by sol-gel method.

    PubMed

    Qu, Jie; Lu, Xiong; Li, Dan; Ding, Yonghui; Leng, Yang; Weng, Jie; Qu, Shuxin; Feng, Bo; Watari, Fumio

    2011-04-01

    Hydroxyapatite (HA) coatings loaded with nanosilver particles is an attractive method to impart the HA coating with antibacterial properties. Producing Ag/HA coatings on porous Ti substrates have been an arduous job since commonly used line-of-sight techniques are not able to deposit uniform coatings on the inner pore surfaces of the porous Ti. In this study, porous Ti scaffolds with high porosity and interconnected structures were prepared by polymer impregnating method. A sol-gel process was used to produce uniform Ag/HA composite coatings on the surfaces of porous Ti substrates. Ca(NO(3) )(2) ·4H(2) O and P(2) O(5) in an ethyl alcohol based system was selected to prepare the sol, which ensured the homogeneous distribution of Ag in the sol. The characterization revealed that silver particles uniformly distributed in the coatings without agglomeration. High antibacterial ratio (>95%), against E. coli and S. albus was expressed by the silver-containing coatings (Ag/HA 0.8 and 1.6 wt %). The biocompatibility of the Ag/HA 0.8 surfaces was as good as that of pure HA surface, as revealed by culturing osteoblasts on them. The results indicated that Ag/HA 0.8 had the good balance between the biocompatibility and antibacterial properties of the coatings. Copyright © 2011 Wiley Periodicals, Inc.

  4. Thermal response of chalcogenide microsphere resonators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ahmad, H; Aryanfar, I; Lim, K S

    2012-05-31

    A chalcogenide microsphere resonator (CMR) used for temperature sensing is proposed and demonstrated. The CMR is fabricated using a simple technique of heating chalcogenide glass and allowing the molten glass to form a microsphere on the waist of a tapered silica fibre. The thermal responses of the CMR is investigated and compared to that of a single-mode-fibre (SMF) based microsphere resonator. It is observed that the CMR sensitivity to ambient temperature changes is 8 times higher than that of the SMF-based microsphere resonator. Heating the chalcogenide microsphere with a laser beam periodically turned on and off shows periodic shifts inmore » the transmission spectrum of the resonator. By injecting an intensity-modulated cw signal through the resonator a thermal relaxation time of 55 ms is estimated.« less

  5. XPS and bioactivity study of the bisphosphonate pamidronate adsorbed onto plasma sprayed hydroxyapatite coatings

    NASA Astrophysics Data System (ADS)

    McLeod, Kate; Kumar, Sunil; Smart, Roger St. C.; Dutta, Naba; Voelcker, Nicolas H.; Anderson, Gail I.; Sekel, Ron

    2006-12-01

    This paper reports the use of X-ray photoelectron spectroscopy (XPS) to investigate bisphosphonate (BP) adsorption onto plasma sprayed hydroxyapatite (HA) coatings commonly used for orthopaedic implants. BPs exhibit high binding affinity for the calcium present in HA and hence can be adsorbed onto HA-coated implants to exploit their beneficial properties for improved bone growth at the implant interface. A rigorous XPS analysis of pamidronate, a commonly used nitrogenous BP, adsorbed onto plasma sprayed HA-coated cobalt-chromium substrates has been carried out, aimed at: (a) confirming the adsorption of this BP onto HA; (b) studying the BP diffusion profile in the HA coating by employing the technique of XPS depth profiling; (c) confirming the bioactivity of the adsorbed BP. XPS spectra of plasma sprayed HA-coated discs exposed to a 10 mM aqueous BP solution (pamidronate) for periods of 1, 2 and 24 h showed nitrogen and phosphorous photoelectron signals corresponding to the BP, confirming its adsorption onto the HA substrate. XPS depth profiling of the 2 h BP-exposed HA discs showed penetration of the BP into the HA matrix to depths of at least 260 nm. The bioactivity of the adsorbed BP was confirmed by the observed inhibition of osteoclast (bone resorbing) cell activity. In comparison to the HA sample, the HA sample with adsorbed BP exhibited a 25-fold decrease in primary osteoclast cells.

  6. Rheological, mechanical and degradable properties of injectable chitosan/silk fibroin/hydroxyapatite/glycerophosphate hydrogels.

    PubMed

    Wu, Jingjing; Liu, Jiaoyan; Shi, Yanmei; Wan, Ying

    2016-12-01

    Silk fibroin (SF) and hydroxyapatite (HA) were incorporated into chitosan/glycerophosphate (GP) system to prepare new types of hydrogels. The formulated chitosan/SF/GP and chitosan/SF/HA/GP solutions were found to be injectable at room temperature, and able to form into hydrogels at near-physiological temperature and pH. Rheological measurements showed that elastic modulus of certain chitosan/SF/GP and chitosan/SF/HA/GP gels could reach around 1.8 and 15kPa, respectively, and was much higher than their respective viscous modulus. Compressive measurements revealed that some chitosan/SF/GP and chitosan/SF/HA/GP gels had 8 and 20-fold modulus and strength higher than the chitosan/GP gel, respectively, confirming that compressive properties of these gels were greatly improved. Results obtained from in vivo degradation demonstrated that degradation endurance of the optimized chitosan/SF/GP and chitosan/SF/HA/GP gels was significantly enhanced as compared to the chitosan/GP gel, and the degradation rate of the gels could be regulated by the SF component alone or by the combination of SF and HA components. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Prediction of mechanical properties of composites of HDPE/HA/EAA.

    PubMed

    Albano, C; Perera, R; Cataño, L; Karam, A; González, G

    2011-04-01

    In this investigation, the behavior of the mechanical properties of composites of high-density polyethylene/hydroxyapatite (HDPE/HA) with and without ethylene-acrylic acid copolymer (EAA) as possible compatibilizer, was studied. Different mathematical models were used to predict their Young's modulus, tensile strength and elongation at break. A comparison with the experimental results shows that the theoretical models of Guth and Kerner modified can be used to predict the Young's modulus. On the other hand, the values obtained by the Verbeek model do not show a good agreement with the experimental data, since different factors that influence the mechanical properties are considered in this model such as: aspect ratio of the reinforcement, interfacial adhesion, porosity and binder content. TEM analysis confirms the discrepancies obtained between the experimental Young's modulus values and those predicted by the Verbeek model. The values of "P", "a" and "σ(A)" suggest that an interaction among the carboxylic groups of the copolymer and the hydroxyl groups of hydroxyapatite might be present. In composites with 20 and 30 wt% of filler, this interaction does not improve the Young's modulus values, since the deviations of the Verbeek model are significant. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. Effect of cell-seeded hydroxyapatite scaffolds on rabbit radius bone regeneration.

    PubMed

    Rathbone, C R; Guda, T; Singleton, B M; Oh, D S; Appleford, M R; Ong, J L; Wenke, J C

    2014-05-01

    Highly porous hydroxyapatite (HA) scaffolds were developed as bone graft substitutes using a template coating process, characterized, and seeded with bone marrow-derived mesenchymal stem cells (BMSCs). To test the hypothesis that cell-seeded HA scaffolds improve bone regeneration, HA scaffolds without cell seeding (HA-empty), HA scaffolds with 1.5 × 10(4) BMSCs (HA-low), and HA scaffolds with 1.5 × 10(6) BMSCs (HA-high) were implanted in a 10-mm rabbit radius segmental defect model for 4 and 8 weeks. Three different fluorochromes were administered at 2, 4, and 6 weeks after implantation to identify differences in temporal bone growth patterns. It was observed from fluorescence histomorphometry analyses that an increased rate of bone infiltration occurred from 0 to 2 weeks (p < 0.05) of implantation for the HA-high group (2.9 ± 0.5 mm) as compared with HA-empty (1.8 ± 0.8 mm) and HA-low (1.3 ± 0.2 mm) groups. No significant differences in bone formation within the scaffold or callus formation was observed between all groups after 4 weeks, with a significant increase in bone regenerated for all groups from 4 to 8 weeks (28.4% across groups). Although there was no difference in bone formation within scaffolds, callus formation was significantly higher in HA-empty scaffolds (100.9 ± 14.1 mm(3) ) when compared with HA-low (57.8 ± 7.3 mm(3) ; p ≤ 0.003) and HA-high (69.2 ± 10.4 mm(3) ; p ≤ 0.02) after 8 weeks. These data highlight the need for a better understanding of the parameters critical to the success of cell-seeded HA scaffolds for bone regeneration. Copyright © 2013 Wiley Periodicals, Inc.

  9. Nano-hydroxyapatite/chitosan-starch nanocomposite as a novel bone construct: Synthesis and in vitro studies.

    PubMed

    Shakir, Mohammad; Jolly, Reshma; Khan, Mohd Shoeb; Iram, Noor e; Khan, Haris M

    2015-09-01

    A novel ternary nanocomposite system incorporating hydroxyapatite, chitosan and starch (n-HA/CS-ST) has been synthesized by co-precipitation method at room temperature, addressing the issues of biocompatibility, mechanical strength and cytotoxicity required for bone tissue engineering. The interactions, crystallite size, surface morphology and thermal stability against n-HA/CS nanocomposite have been obtained by comparing the results of FTIR, SEM, TEM, DLS, XRD and TGA/DTA. A comparative study of bioactivity and thermal stability of n-HA/CS and n-HA/CS-ST nanocomposites revealed that the incorporation of starch as templating agent enhanced these properties in n-HA/CS-ST nanocomposite. A lower swelling rate of n-HA/CS-ST relative to n-HA/CS indicates a higher mechanical strength supportive of bone tissue ingrowths. The MTT assay on murine fibroblast L929 and human osteoblasts-like MG-63 cells and in vitro bioactivity of n-HA/CS-ST matrix referred superior non-toxic nature of n-HA/CS-ST nanocomposite and greater possibility of osteointegration in vivo respectively. Furthermore n-HA/CS-ST exhibited improved antibacterial property against both Gram-positive and Gram-negative bacteria relative to n-HA/CS. Copyright © 2015. Published by Elsevier B.V.

  10. Carbon fibers with a nano-hydroxyapatite coating as an excellent biofilm support for bioreactors

    NASA Astrophysics Data System (ADS)

    Liu, Qijie; Zhang, Chao; Bao, Yanling; Dai, Guangze

    2018-06-01

    A biofilm support with high biocompatibility is needed for bioreactors. A nano-hydroxyapatite (HA) coating on carbon fibers (CFs) was prepared by electrochemical deposition (ECD). The sludge immobilization assays, bacterial cells adhesion assays and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory were used to evaluate the capacity of CF supports to immobilize activated sludge and bacterial cells. The sludge immobilization and bacterial cells adhesion assays illustrated that HA coating could enhance the capacity of CFs to immobilize microorganisms. SEM images showed that HA and bacterial cells formed a dense film on CFs surface. In addition, HA, acting as a glue, could combine CFs with bacterial cells or between cells, which helped CFs capture more bacterial cells. DLVO theory illustrated that CFs with HA coating had a lower total interaction energy than CFs without handling, explaining the higher capacity of CFs with HA coating to immobilize bacterial cells. This result was owning to the less negative zeta potential and higher hydrophilicity of CFs with HA coating, and the hydrophilicity made a greater contribution to the lower total interaction energy. Experiments and theory reveal that HA coating could enhance the biocompatibility of CFs, and CFs with HA coating could be used as an excellent biofilm support for bioreactors.

  11. Preparation and mechanical properties of carbon fiber reinforced hydroxyapatite/polylactide biocomposites.

    PubMed

    Shen, Lie; Yang, Hui; Ying, Jia; Qiao, Fei; Peng, Mao

    2009-11-01

    A novel biocomposite of carbon fiber (CF) reinforced hydroxyapatite (HA)/polylactide (PLA) was prepared by hot pressing a prepreg which consisting of PLA, HA and CF. The prepreg was manufactured by solvent impregnation process. Polymer resin PLA dissolved with chloroform was mixed with HA. After reinforcement CF bundle was impregnated in the mixture, the solvent was dried completely and subsequently hot-pressed uniaxially under a pressure of 40 MPa at 170 degrees C for 20 min. A study was carried out to investigate change in mechanical properties of CF/HA/PLA composites before and after degradation in vitro. The composites have excellent mechanical properties. A peak showed in flexural strength, flexural modulus and shear strength aspects, reaching up 430 MPa, 22 GPa, 212 MPa, respectively, as the HA content increased. Degraded in vitro for 3 months, the flexural strength and flexural modulus of the CF/HA/PLA fell 13.2% and 5.4%, respectively, while the shear strength of the CF/HA/PLA composites remains at the 190 MPa level. The SEM photos showed that there were gaps between the PLA matrix and CF after degradation. Water uptake increased to 5%, but the mass loss rate was only 1.6%. The pH values of the PBS dropped less than 0.1. That's because the alkaline of HA neutralize the acid degrades from PLA, which can prevent the body from the acidity harm.

  12. The importance of amino acid interactions in the crystallization of hydroxyapatite

    PubMed Central

    Jahromi, M. Tavafoghi; Yao, G.; Cerruti, M.

    2013-01-01

    Non-collagenous proteins (NCPs) inhibit hydroxyapatite (HA; Ca5(PO4)3OH) formation in living organisms by binding to nascent nuclei of HA and preventing their further growth. Polar and charged amino acids (AAs) are highly expressed in NCPs, and the negatively charged ones, such as glutamic acid (Glu) and phosphoserine (P-Ser) seem to be mainly responsible for the inhibitory effect of NCPs. Despite the recognized importance of these AAs on the behaviour of NCPs, their specific effect on HA crystallization is still unclear, and controversial results have been reported concerning the efficacy of HA inhibition of positively versus negatively charged AAs. We focused on a positively charged (arginine, Arg) and a negatively charged (Glu) AA, and their combination in the same solution. We studied their inhibitory effect on HA nucleation and growth at physiological temperature and pH and we determined the mechanism by which they can affect HA crystallization. Our results showed a strong inhibitory effect of Arg on HA nucleation; however, Glu was more effective in inhibiting HA crystal growth during the growth stage. The combination of Glu and Arg was less effective in controlling HA nucleation, but it inhibited HA crystal growth. We attributed these differences to the stability of complexes formed between AAs and calcium and phosphate ions at the nucleation stage, and in bonding strength of AAs to HA crystal faces during the growth stage. The AAs also influenced the morphology of synthesized HA. Presence of either Arg or Glu resulted in the formation of spherulites consisting of preferentially oriented nanoplatelets orientation. This was attributed to kinetic factors favoring growth front nucleation (GFN) mechanism. PMID:23269851

  13. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, William E.

    1984-01-01

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  14. Fabrication of glass microspheres with conducting surfaces

    DOEpatents

    Elsholz, W.E.

    1982-09-30

    A method for making hollow glass microspheres with conducting surfaces by adding a conducting vapor to a region of the glass fabrication furnace. As droplets or particles of glass forming material pass through multiple zones of different temperature in a glass fabrication furnace, and are transformed into hollow glass microspheres, the microspheres pass through a region of conducting vapor, forming a conducting coating on the surface of the microspheres.

  15. Eggshell-Derived Hydroxyapatite: A New Era in Bone Regeneration.

    PubMed

    Kattimani, Vivekanand; Lingamaneni, Krishna Prasad; Chakravarthi, Pandi Srinivas; Kumar, T S Sampath; Siddharthan, Arjunan

    2016-01-01

    Defects of maxillofacial skeleton lead to personal (functional and aesthetic), social and behavioral problems; which make the person to isolate from the main stream of society. So, bone regeneration is the need for proper structure, function, and aesthetics following cyst enucleation, trauma, and tumor ablative surgery; which helps for overall health of the individual. The preliminary study is planned to evaluate and compare the efficacy of eggshell-derived hydroxyapatite (EHA) and synthetic hydroxyapatite (SHA) following cystectomy. Microwave-processed calcium deficient EHA and commercially available SHA are used for grafting. Total 20 patients enrolled in this study, consisting 10 in each group between 20 and 45 years of age. All the patients were evaluated for bone regeneration at first, second, third, and sixth month's interval, postsurgically, using radiovisiograph and clinical parameters. The bone formation characteristics vary at second month when compared to SHA. This difference may be because of the kinetics involved in the regeneration pattern. The pattern of bone healing was trabecular after third month, indicating complete bone formation. The study showed constant raise of density and remained same at the end of study period. Both EHA and SHA graft materials are equally efficient in early bone regeneration. Within the limitations of this study the EHA showed promising results. Which indicates the eggshell waste-bio mineral is worthwhile raw material for the production of HA and is a Go Green procedure. Eggshell-derived hydroxyapatite is economic, compared with SHA.

  16. Effect of bioactive extruded PLA/HA composite films on focal adhesion formation of preosteoblastic cells.

    PubMed

    Persson, Maria; Lorite, Gabriela S; Kokkonen, Hanna E; Cho, Sung-Woo; Lehenkari, Petri P; Skrifvars, Mikael; Tuukkanen, Juha

    2014-09-01

    The quality of the initial cell attachment to a biomaterial will influence any further cell function, including spreading, proliferation, differentiation and viability. Cell attachment is influenced by the material's ability to adsorb proteins, which is related to the surface chemistry and topography of the material. In this study, we incorporated hydroxyapatite (HA) particles into a poly(lactic acid) (PLA) composite and evaluated the surface structure and the effects of HA density on the initial cell attachment in vitro of murine calvarial preosteoblasts (MC3T3-EI). Scanning electron microscopy (SEM), atomic force microscopy (AFM) and infrared spectroscopy (FTIR) showed that the HA particles were successfully incorporated into the PLA matrix and located at the surface which is of importance in order to maintain the bioactive effect of the HA particles. SEM and AFM investigation revealed that the HA density (particles/area) as well as surface roughness increased with HA loading concentration (i.e. 5, 10, 15 and 20wt%), which promoted protein adsorption. Furthermore, the presence of HA on the surface enhanced cell spreading, increased the formation of actin stress fibers and significantly improved the expression of vinculin in MC3T3-E1 cells which is a key player in the regulation of cell adhesion. These results suggest the potential utility of PLA/HA composites as biomaterials for use as a bone substitute material and in tissue engineering applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. EDTA assisted synthesis of hydroxyapatite nanoparticles for electrochemical sensing of uric acid.

    PubMed

    Kanchana, P; Sekar, C

    2014-09-01

    Hydroxyapatite nanoparticles have been synthesized using EDTA as organic modifier by a simple microwave irradiation method and its application for the selective determination of uric acid (UA) has been demonstrated. Electrochemical behavior of uric acid at HA nanoparticle modified glassy carbon electrode (E-HA/GCE) has been investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and amperometry. The E-HA modified electrode exhibits efficient electrochemical activity towards uric acid sensing without requiring enzyme or electron mediator. Amperometry studies revealed that the fabricated electrode has excellent sensitivity for uric acid with the lowest detection limit of 142 nM over a wide concentration range from 1 × 10(-7) to 3 × 10(-5)M. Moreover, the studied E-HA modified GC electrode exhibits a good reproducibility and long-term stability and an admirable selectivity towards the determination of UA even in the presence of potential interferents. The analytical performance of this sensor was evaluated for the detection of uric acid in human urine and blood serum samples. Copyright © 2014. Published by Elsevier B.V.

  18. Study on clinical application of nano-hydroxyapatite bone in bone defect repair.

    PubMed

    Zhu, Weimin; Wang, Daping; Xiong, Jianyi; Liu, Jianquan; You, Wei; Huang, Jianghong; Duan, Li; Chen, Jielin; Zeng, Yanjun

    2015-01-01

    To study the clinical effect of bone defect treated with nano-hydroxyapatite(Nano-HA) artificial bone. From September 2009 to June 2012, 27 cases of bone defect were analyzed retrospectively. The position of bone defect included humerus, radius, ulna, femur, tibia and calcaneus. The range of bone defect was from 0.3 × 1.0 cm to 3 × 6.5 cm. Among them, there were 22 cases with fractures and 5 cases with tumors. All patients were treated with Nano-HA artificial bone. The ability of bone defect repair was evaluated by X-ray exams performed preoperatively and postoperatively. HSS scores were adopted for final evaluation at the latest follow-up. The patients were followed up from 11 to 26 months (average of 18.5 months). No general side effects occurred. X-ray photo showed an integrity interface between Nano-HA and bone. Primary healing was obtained in all cases without any complication. The Nano-HA artificial bone had a good biocompatibility and could be an ideal artificial bone in the reconstruction of bone defect.

  19. Fabrication and characterization of nanoengineered biocompatible n-HA/chitosan-tamarind seed polysaccharide: Bio-inspired nanocomposites for bone tissue engineering.

    PubMed

    Shakir, Mohammad; Zia, Iram; Rehman, Abdur; Ullah, Rizwan

    2018-05-01

    In this communication we describe the fabrication of nano-hydroxyapatite/chitosan-tamarind seed polysaccharide (n-HA/CS-TSP) nanocomposite with a weight ratio of 70/20/10, 70/15/15 and 70/10/20, respectively through a co-precipitation method. A comparative assessment of the properties of n-HA/CS-TSP and n-HA/CS nanocomposites was done by FT-IR, SEM-EDX, TEM, TGA/DTA, XRD and mechanical testing. The results suggested strong chemical interactions between the three components, decreased particle size and homogeneous dispersion of n-HA particles in n-HA/CS-TSP as compared to n-HA/CS. The n-HA/CS-TSP (70/10/20) showed the most porous and rough surface, enhanced thermal stability and highest compressive strength (4.0 MPa) and modulus (81 MPa). In addition, n-HA/CS-TSP (70/10/20) exhibited greater swelling character, acceptable degradation and increased biomineralization in simulated body fluid (SBF) as compared to n-HA/CS-TSP (70/20/10, 70/15/15) and n-HA/CS nanocomposites. The superior non-toxic response with MG-63 cells and better haemocompatibility was observed with n-HA/CS-TSP (70/15/15). Thereby, n-HA/CS-TSP nanocomposites could be promising alternative biomaterials in the field of bone tissue engineering compared to the n-HA/CS nanocomposite. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Effects of sintering temperature on electrical properties of sheep enamel hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Dumludag, F.; Gunduz, O.; Kılıc, O.; Kılıc, B.; Ekren, N.; Kalkandelen, C.; Oktar, F. N.

    2017-12-01

    Bioceramics, especially calcium phosphate based bioceramics, whose examples are hydroxyapatite, and calcium phosphate powders have been widely used in the biomedical engineering applications. Hydroxyapatite (HA) is one of the most promising biomaterials, which are derived from natural sources, chemical method, animal like dental enamel and corals. The influence of sintering temperature on the electrical properties (i.e. DC conductivity, AC conductivity) of samples of sintered sheep enamel (SSSE) was studied in air and in vacuum ambient at room temperature. The sheep enamel were sintered at varying temperatures between 1000°C and 1300°C. DC conductivity results revealed that while dc conductivity of the SSSE decreases with increasing the sintering temperature in air ambient the values increased with increasing the sintering temperature in vacuum ambient. AC conductivity measurements were performed in the frequency range of 40 Hz - 105 Hz. The results showed that ac conductivity values decrease with increasing the sintering temperature.

  1. Magnetic susceptibility characterisation of superparamagnetic microspheres

    NASA Astrophysics Data System (ADS)

    Grob, David Tim; Wise, Naomi; Oduwole, Olayinka; Sheard, Steve

    2018-04-01

    The separation of magnetic materials in microsystems using magnetophoresis has increased in popularity. The wide variety and availability of magnetic beads has fuelled this drive. It is important to know the magnetic characteristics of the microspheres in order to accurately use them in separation processes integrated on a lab-on-a-chip device. To investigate the magnetic susceptibility of magnetic microspheres, the magnetic responsiveness of three types of Dynabeads microspheres were tested using two different approaches. The magnetophoretic mobility of individual microspheres is studied using a particle tracking system and the magnetization of each type of Dynabeads microsphere is measured using SQUID relaxometry. The magnetic beads' susceptibility is obtained at four different applied magnetic fields in the range of 38-70 mT for both the mobility and SQUID measurements. The susceptibility values in both approaches show a consistent magnetic field dependence.

  2. Hydroxyapatite coating on cobalt alloys using electrophoretic deposition method for bone implant application

    NASA Astrophysics Data System (ADS)

    Aminatun; M, Shovita; I, Chintya K.; H, Dyah; W, Dwi

    2017-05-01

    Damage on bone due to osteoporosis and cancer triggered high demand for bone implant prosthesis which is a permanent implant. Thus, a prosthesis coated with hydroxyapatite (HA) is required because it is osteoconductive that can trigger the growth of osteoblast cells. The purpose of this study is to determine the optimum concentration of HA suspension in terms of the surface morphology, coating thickness, adhesion strength and corrosion rate resulting in the HA coating with the best characteristics for bone implant. Coating using electrophoretic deposition (EPD) method with concentrations of 0.02M, 0.04M, 0.06M, 0.08M, and 0.1M was performed on the voltage and time of 120V and 30 minutes respectively. The process was followed by sintering at the temperature of 900 °C for 10 minutes. The results showed that the concentration of HA suspension influences the thickness and the adhesion of layer of HA. The higher the concentration of HA-ethanol suspension the thicker the layer of HA, but its coating adhesion strength values became lower. The concentration of HA suspension of 0.04 M is the best concentration, with characteristics that meet the standards of the bone implant prosthesis. The characteristics are HA coating thickness of 199.93 ± 4.85 μm, the corrosion rate of 0.0018 mmpy and adhesion strength of 4.175 ± 0.716 MPa.

  3. Mechanical, Rheological, and Bioactivity Properties of Ultra High-Molecular-Weight Polyethylene Bioactive Composites Containing Polyethylene Glycol and Hydroxyapatite

    PubMed Central

    Ahmad, Mazatusziha; Wahit, Mat Uzir; Abdul Kadir, Mohammed Rafiq; Mohd Dahlan, Khairul Zaman

    2012-01-01

    Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis. PMID:22666129

  4. Crystal imperfection studies of pure and silicon substituted hydroxyapatite using Raman and XRD.

    PubMed

    Zou, Shuo; Huang, Jie; Best, Serena; Bonfield, William

    2005-12-01

    Hydroxyapatite (HA) is important in biomedical applications because of its chemical similarity to the mineral content of bone and its consequent bioactivity. Silicon substitution into the hydroxyapatite crystal lattice was found to enhance its bioactivity both in vitro and in vivo [1, 2]. However, the mechanism for the enhancement is still not well understood. In this paper, the crystal imperfections introduced by silicon substitution were studied using XRD and Raman spectroscopy. It was found that silicon substitution did not introduce microstrain, but deceased the crystal size in the hk0 direction. Three new vibration modes and peak broadening were observed in Raman spectra following silicon incorporation. The imperfections introduced by silicon substitution may play a role in enhancing bioactivity. A phenomenological relationship between the width of the PO4 v1 peak and crystal size was established.

  5. Polarization Dependent Whispering Gallery Modes in Microspheres

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory (Inventor); Wrbanek, Susan Y. (Inventor)

    2016-01-01

    A tunable resonant system is provided and includes a microsphere that receives an incident portion of a light beam generated via a light source, the light beam having a fundamental mode, a waveguide medium that transmits the light beam from the light source to the microsphere, and a polarizer disposed in a path of the waveguide between the light source and the microsphere. The incident portion of the light beam creates a fundamental resonance inside the microsphere. A change in a normalized frequency of the wavelength creates a secondary mode in the waveguide and the secondary mode creates a secondary resonance inside the microsphere.

  6. Electroactive Mg2+-Hydroxyapatite Nanostructured Networks against Drug-Resistant Bone Infection Strains.

    PubMed

    Andrés, Nancy C; Sieben, Juan M; Baldini, Mónica; Rodríguez, Carlos H; Famiglietti, Ángela; Messina, Paula V

    2018-06-13

    Surface colonization competition between bacteria and host cells is one of the critical factors involved in tissue/implant integration. Current biomaterials are evaluated for their ability both of withstanding favorable responses of host tissue cells and of resisting bacterial contamination. In this work, the antibacterial ability of biocompatible Mg 2+ -substituted nanostructured hydroxyapatite (HA) was investigated. The densities of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli strains were significantly decreased after culture in the presence of Mg-substituted HA materials in direct correlation with Mg 2+ -Ca 2+ switch in the HA lattice. It was noticed that this decrease was accompanied by a minimal alteration of bacterial environments; therefore, the Mg 2+ -HA antibacterial effect was associated with the material surface topography and it electroactive behavior. It was observed that 2.23 wt % Mg 2+ -HA samples exhibited the best antibacterial performance; it decreased 2-fold the initial population of E. coli, P. aeruginosa, and S. aureus at the intermediate concentration (50 mg mL -1 of broth). Our results reinforce the potential of Mg-HA nanostructured materials to be used in antibacterial coatings for implantable devices and/or medicinal materials to prevent bone infection and to promote wound healing.

  7. A microstructural study of the degradation and calcium release from hydroxyapatite-calcium oxide ceramics made by infiltration.

    PubMed

    Zhang, Qinghao; Schmelzer, Eva; Gerlach, Jörg C; Nettleship, Ian

    2017-04-01

    Hydroxyapatite pellets, partially densified in a low-temperature heat treatment, were infiltrated with calcium nitrate solution followed by in-situ precipitation of Ca(OH) 2 and CaCO 3 . The infiltrated bodies were then densified to high relative density and the calcium carbonate transformed to calcium oxide during sintering and resulted in biphasic hydroxyapatite-CaO ceramics. This work investigated the influence of the infiltration on surface morphology, weight change, and microstructural-level degradation caused by exposure to saline at pH=7.4 and a temperature of 20°C. The CaO rendered the materials more susceptible to degradation, and released calcium into the saline faster than single phase, calcium deficient hydroxyapatite (HA) that were used as a control. In consequence, these ceramics could be used to release calcium into the culture microenvironments of bone tissue or bone marrow cells next to a scaffold surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Hybrid Macro-Porous Titanium Ornamented by Degradable 3D Gel/nHA Micro-Scaffolds for Bone Tissue Regeneration

    PubMed Central

    Yin, Bo; Ma, Pei; Chen, Jun; Wang, Hai; Wu, Gui; Li, Bo; Li, Qiang; Huang, Zhifeng; Qiu, Guixing; Wu, Zhihong

    2016-01-01

    Porous titanium is a kind of promising material for bone substitution, while its bio-inert property results in demand of modifications to improve the osteointegration capacity. In this study, gelatin (Gel) and nano-hydroxyapatite (nHA) were used to construct 3D micro-scaffolds in the pores of porous titanium in the ratios of Gel:nHA = 1:0, Gel:nHA = 1:1, and Gel:nHA = 1:3, respectively. Cell attachment and proliferation, and gene and protein expression levels of osteogenic markers were evaluated in MC3T3-E1 cells, followed by bone regeneration assessment in a rabbit radius defect model. All hybrid scaffolds with different composition ratio were found to have significant promotional effects in cell adhesion, proliferation and differentiation, in which the group with Gel:nHA = 1:1 showed the best performance in vitro, as well as the most bone regeneration volume in vivo. This 3D micro-scaffolds modification may be an innovative method for porous titanium ornamentation and shows potential application values in clinic. PMID:27092492

  9. Hybrid Macro-Porous Titanium Ornamented by Degradable 3D Gel/nHA Micro-Scaffolds for Bone Tissue Regeneration.

    PubMed

    Yin, Bo; Ma, Pei; Chen, Jun; Wang, Hai; Wu, Gui; Li, Bo; Li, Qiang; Huang, Zhifeng; Qiu, Guixing; Wu, Zhihong

    2016-04-15

    Porous titanium is a kind of promising material for bone substitution, while its bio-inert property results in demand of modifications to improve the osteointegration capacity. In this study, gelatin (Gel) and nano-hydroxyapatite (nHA) were used to construct 3D micro-scaffolds in the pores of porous titanium in the ratios of Gel:nHA = 1:0, Gel:nHA = 1:1, and Gel:nHA = 1:3, respectively. Cell attachment and proliferation, and gene and protein expression levels of osteogenic markers were evaluated in MC3T3-E1 cells, followed by bone regeneration assessment in a rabbit radius defect model. All hybrid scaffolds with different composition ratio were found to have significant promotional effects in cell adhesion, proliferation and differentiation, in which the group with Gel:nHA = 1:1 showed the best performance in vitro, as well as the most bone regeneration volume in vivo. This 3D micro-scaffolds modification may be an innovative method for porous titanium ornamentation and shows potential application values in clinic.

  10. Computer-Assisted Optimization of Electrodeposited Hydroxyapatite Coating Parameters on Medical Alloys

    NASA Astrophysics Data System (ADS)

    Coşkun, M. İbrahim; Karahan, İsmail H.; Yücel, Yasin; Golden, Teresa D.

    2016-04-01

    CoCrMo bio-metallic alloys were coated with a hydroxyapatite (HA) film by electrodeposition using various electrochemical parameters. Response surface methodology and central composite design were used to optimize deposition parameters such as electrolyte pH, deposition potential, and deposition time. The effects of the coating parameters were evaluated within the limits of solution pH (3.66 to 5.34), deposition potential (-1.13 to -1.97 V), and deposition time (6.36 to 73.64 minutes). A 5-level-3-factor experimental plan was used to determine ideal deposition parameters. Optimum conditions for the deposition parameters of the HA coating with high in vitro corrosion performance were determined as electrolyte pH of 5.00, deposition potential of -1.8 V, and deposition time of 20 minutes.

  11. Synthesis, characterization, biocompatibility of hydroxyapatite-natural polymers nanocomposites for dentistry applications.

    PubMed

    Chung, Jin-Hwan; Kim, Young Kyung; Kim, Kyo-Han; Kwon, Tae-Yub; Vaezmomeni, Seyede Ziba; Samiei, Mohammad; Aghazadeh, Marzyeh; Davaran, Soodabeh; Mahkam, Mehrdad; Asadi, Ghale; Akbarzadeh, Abolfazl

    2016-01-01

    Hydroxyapatite (HA), the main mineral component of bones and teeth, was synthesized by using the reaction between calcium nitrate tetrahydrate Ca(NO3)2∙4H2O and diammonium hydrogen phosphate (NH4)2HPO4 (DAHP) with a chemical precipitation method. The objective of this study is to utilize novel inorganic-organic nanocomposites for biomedical applications. HA is an inorganic component (75% w) and chitosan, alginate and albumin (Egg white) are organic components of nanocomposites (25% w). Nanocomposites were prepared in deionized water solutions, at room temperature, using a mechanical and magnetic stirrer for 48 h. The microstructure and morphology of sintered n-HAP were tested at different preheating temperature and laser sintering speed with scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR).

  12. Preparation, characterization, and in vitro osteoblast functions of a nano-hydroxyapatite/polyetheretherketone biocomposite as orthopedic implant material

    PubMed Central

    Ma, Rui; Tang, Songchao; Tan, Honglue; Lin, Wentao; Wang, Yugang; Wei, Jie; Zhao, Liming; Tang, Tingting

    2014-01-01

    A bioactive composite was prepared by incorporating 40 wt% nano-hydroxyapatite (nHA) into polyetheretherketone (PEEK) through a process of compounding, injection, and molding. The mechanical and surface properties of the nHA/PEEK composite were characterized, and the in vitro osteoblast functions in the composite were investigated. The mechanical properties (elastic modulus and compressive strength) of the nHA/PEEK composite increased significantly, while the tensile strength decreased slightly as compared with PEEK. Further, the addition of nHA into PEEK increased the surface roughness and hydrophilicity of the nHA/PEEK composite. In cell tests, compared with PEEK and ultra-high-molecular-weight polyethylene, it was found that the nHA/PEEK composite could promote the functions of MC3T3-E1 cells, including cell attachment, spreading, proliferation, alkaline phosphatase activity, calcium nodule formation, and expression of osteogenic differentiation-related genes. Incorporation of nHA into PEEK greatly improved the bioperformance of PEEK. The nHA/PEEK composite might be a promising orthopedic implant material. PMID:25170265

  13. Research on the preparation, biocompatibility and bioactivity of magnesium matrix hydroxyapatite composite material.

    PubMed

    Linsheng, Li; Guoxiang, Lin; Lihui, Li

    2016-08-12

    In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60 V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity.

  14. Characterization of Multiwalled Carbon Nanotube-Reinforced Hydroxyapatite Composites Consolidated by Spark Plasma Sintering

    PubMed Central

    Kim, Duk-Yeon; Han, Young-Hwan; Lee, Jun Hee; Kang, Inn-Kyu; Jang, Byung-Koog; Kim, Sukyoung

    2014-01-01

    Pure HA and 1, 3, 5, and 10 vol% multiwalled carbon nanotube- (MWNT-) reinforced hydroxyapatite (HA) were consolidated using a spark plasma sintering (SPS) technique. The relative density of pure HA increased with increasing sintering temperature, but that of the MWNT/HA composite reached almost full density at 900°C, and then decreased with further increases in sintering temperature. The relative density of the MWNT/HA composites increased with increasing MWNT content due to the excellent thermal conductivity of MWNTs. The grain size of MWNT/HA composites decreased with increasing MWNT content and increased with increasing sintering temperature. Pull-out toughening of the MWNTs of the MWNT/HA composites was observed in the fractured surface, which can be used to predict the improvement of the mechanical properties. On the other hand, the existence of undispersed or agglomerate MWNTs in the MWNT/HA composites accompanied large pores. The formation of large pores increased with increasing sintering temperature and MWNT content. The addition of MWNT in HA increased the hardness and fracture toughness by approximately 3~4 times, despite the presence of large pores produced by un-dispersed MWNTs. This provides strong evidence as to why the MWNTs are good candidates as reinforcements for strengthening the ceramic matrix. The MWNT/HA composites did not decompose during SPS sintering. The MWNT-reinforced HA composites were non-toxic and showed a good cell affinity and morphology in vitro for 1 day. PMID:24724100

  15. Characterisations of collagen-silver-hydroxyapatite nanocomposites

    NASA Astrophysics Data System (ADS)

    Ciobanu, C. S.; Popa, C. L.; Petre, C. C.; Jiga, G.; Trusca, R.; Predoi, D.

    2016-05-01

    The XRD analysis were performed to confirm the formation of hydroxyapatite structure in collagen-silver-hydroxyapatite nanocomposites. The molecular interaction in collagen-hydroxyapatite nanocomposites was highlighted by Fourier transform infrared spectroscopy (FTIR) analysis. The SEM showed a nanostructure of collagen-silverhydroxyapatite nanocomposites composed of nano needle-like particles in a veil with collagen texture. The presence of vibrational groups characteristics to the hydroxyapatite structure in collagen-silver-hydroxyapatite (AgHApColl) nanocomposites was investigated by FTIR.

  16. Influence of pretreatment on the surface characteristics of PLLA fibers and subsequent hydroxyapatite coating.

    PubMed

    Peng, F; Olson, J R; Shaw, M T; Wei, M

    2009-01-01

    A fibrous precursor for bone repair composites was made by coating poly(L-lactide) (PLLA) fibers with hydroxyapatite (HA) using a biomimetic method. To enhance the bonding between the HA coating and the PLLA fiber, PLLA fibers were etched with either sodium hydroxide or sodium hypochlorite to generate carboxyl groups on fiber surfaces. The experiments were designed to determine the influence of etching on the fiber surface morphology and chemistry as well as the subsequent HA coating on the etched fiber surfaces. It was found that the etching pretreatment increased the roughness as well as the hydrophilicity of fibers, indicating that hydrolysis of PLLA chains had taken place on fiber surfaces. The etching pretreatment also promoted HA coating formation by introducing thicker coating on the surface of fibers with a longer etching time, a higher etching concentration, or with NaOCl as the etching agent. A mechanism of surface hydrolysis and oxidation of PLLA was proposed. (c) 2008 Wiley Periodicals, Inc.

  17. In vitro evaluation of biodegradable microspheres with surface-bound ligands.

    PubMed

    Keegan, Mark E; Royce, Sara M; Fahmy, Tarek; Saltzman, W Mark

    2006-02-21

    Protein ligands were conjugated to the surface of biodegradable microspheres. These microsphere-ligand conjugates were then used in two in vitro model systems to evaluate the effect of conjugated ligands on microsphere behavior. Microsphere retention in agarose columns was increased by ligands on the microsphere surface specific for receptors on the agarose matrix. In another experiment, conjugating the lectin Ulex europaeus agglutinin 1 to the microsphere surface increased microsphere adhesion to Caco-2 monolayers compared to control microspheres. This increase in microsphere adhesion was negated by co-administration of l-fucose, indicating that the increase in adhesion is due to specific interaction of the ligand with carbohydrate receptors on the cell surface. These results demonstrate that the ligands conjugated to the microspheres maintain their receptor binding activity and are present on the microsphere surface at a density sufficient to target the microspheres to both monolayers and three-dimensional matrices bearing complementary receptors.

  18. Production of biologically safe and mechanically improved reduced graphene oxide/hydroxyapatite composites

    NASA Astrophysics Data System (ADS)

    Elif, Öztürk; Belma, Özbek; İlkay, Şenel

    2017-01-01

    As research trends included the improvement of the mechanical properties of hydroxyapatite (HA) for biological applications, HA was reinforced with different concentrations of reduced graphene oxide (RGO) in HA. In this context, graphene oxide was synthesized using the chemical exfoliation method and reduced using an environmentally safe and green method. As a green method, RGO was obtained using Melissa officinalis (melisa) extract and used as a second phase combination to the HA structure. RGO-HA composites with different concentrations of RGO in HA (0.25, 0.5, 1.0, 2.0% wt.) were prepared using the liquid precipitation method. Then they were pelleted and sintered. Characterization studies were carried out using UV-vis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zetasizer (ZS), x-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The mechanical properties of the composites were analyzed using a universal testing machine. Compared to pure HA, the compressive strength values of composites were increased significantly with the increase in RGO content. The optimum increase was observed for the RGO-HA (1%) composite, which was 3.2 times higher than the pure HA sample. Therefore, the RGO-HA (1%) composite was chosen as the best composition, and its cytotoxic and proliferative effects were examined using a minimum essential media elution test and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The results showed that RGO-HA (1%) composites are biocompatible and even though they are proliferative at concentrations lower than 25%.

  19. Synthesis and structural characterization of nano-hydroxyapatite biomaterials prepared by microwave processing

    NASA Astrophysics Data System (ADS)

    Ramli, Rosmamuhamadani; Arawi, Ainaa Zafirah Omar; Talari, Mahesh Kumar; Mahat, Mohd Muzamir; Jais, Umi Sarah

    2012-07-01

    Synthetic hydroxyapatite, (HA, Ca10(PO4)6(OH)2), is an attractive and widely utilized bio-ceramic material for orthopedic and dental implants because of its close resemblance of native tooth and bone crystal structure. Synthetic HA exhibits excellent osteoconductive properties. Osteoconductivity means the ability to provide the appropriate scaffold or template for bone formation. Calcium phosphate biomaterials [(HA), tri-calcium phosphate (TCP) and biphasic calcium phosphate (HA/TCP)] with appropriate three-dimensional geometry are able to bind and concentrate endogenous bone morphogenetic proteins in circulation, and may become osteoinductive and can be effective carriers of bone cell seeds. This HA can be used in bio-implants as well as drug delivery application due to the unique properties of HA. Biomaterials synthesized from the natural species like mussel shells have additional benefits such as high purity, less expensive and high bio compatibility. In this project, HA-nanoparticles of different crystallite size were prepared by microwave synthesis of precursors. High purity CaO was extracted from the natural mussel shells for the synthesis of nano HA. Dried nano HA powders were analyzed using X-Ray Diffraction (XRD) technique for the determination of crystal structure and impurity content. Scanning Electron Microscopic (SEM) investigation was employed for the morphological investigation of nano HA powders. From the results obtained, it was concluded that by altering the irradiation time, nano HA powders of different crystallite sizes and morphologies could be produced. Crystallite sizes calculated from the XRD patterns are found to be in the range of 10-55 nm depending on the irradiation time.

  20. Electrospun polyurethane/hydroxyapatite bioactive scaffolds for bone tissue engineering: the role of solvent and hydroxyapatite particles.

    PubMed

    Tetteh, G; Khan, A S; Delaine-Smith, R M; Reilly, G C; Rehman, I U

    2014-11-01

    Polyurethane (PU) is a promising polymer to support bone-matrix producing cells due to its durability and mechanical resistance. In this study two types of medical grade poly-ether urethanes Z3A1 and Z9A1 and PU-Hydroxyapatite (PU-HA) composites were investigated for their ability to act as a scaffold for tissue engineered bone. PU dissolved in varying concentrations of dimethylformamide (DMF) and tetrahydrofuran (THF) solvents were electrospun to attain scaffolds with randomly orientated non-woven fibres. Bioactive polymeric composite scaffolds were created using 15 wt% Z3A1 in a 70/30 DMF/THF PU solution and incorporating micro- or nano-sized HA particles in a ratio of 3:1 respectively, whilst a 25 wt% Z9A1 PU solution was doped in ratio of 5:1. Chemical properties of the resulting composites were evaluated by FTIR and physical properties by SEM. Tensile mechanical testing was carried out on all electrospun scaffolds. MLO-A5 osteoblastic mouse cells and human embryonic mesenchymal progenitor cells, hES-MPs were seeded on the scaffolds to test their biocompatibility and ability to support mineralised matrix production over a 28 day culture period. Cell viability was assayed by MTT and calcium and collagen deposition by Sirius red and alizarin red respectively. SEM images of both electrospun PU scaffolds and PU-HA composite scaffolds showed differences in fibre morphology with changes in solvent combinations and size of HA particles. Inclusion of THF eliminated the presence of beads in fibres that were present in scaffolds fabricated with 100% DMF solvent, and resulted in fibres with a more uniform morphology and thicker diameters. Mechanical testing demonstrated that the Young׳s Modulus and yield strength was lower at higher THF concentrations. Inclusion of both sizes of HA particles in PU-HA solutions reinforced the scaffolds leading to higher mechanical properties, whilst FTIR characterisation confirmed the presence of HA in all composite scaffolds. Although

  1. Encapsulation of anticancer drug copper bis(8-hydroxyquinoline) in hydroxyapatite for pH-sensitive targeted delivery and slow release.

    PubMed

    Weerasuriya, D R K; Wijesinghe, W P S L; Rajapakse, R M G

    2017-02-01

    There is a conspicuous progress in increasing anticancer drug delivery through the utilization of nanoparticles (NPs) as drug delivery agents. Hydroxyapatite (HA) gives improved clinical effectiveness of drugs by reducing systemic toxicity and broadening the spectrum of drug delivery since it is biocompatible and it can be targeted towards tumor cells. Herein, investigation of the potential of enhancing controlled drug release of the template model drug, copper bis-(8-hydroxyquinoline), by encapsulating it in hollow hydroxyapatite nano-carriers, is presented. Hydroxyapatite nanoparticles are synthesized by following four different routes to optimize its efficacy of drug loading. Copper bis-(8-hydroxyquinoline) is encapsulated by Method (a) which was effected by stirring the model drug and porous HA NPs in colloidal solution and Method (b) which was done during synthesis of hydroxyapatite nanoparticles in a solution of the model drug. In synthesizing nanoporous HA NPs, calcium carbonate is used as a template to create voids in HA. In each method, Ca/P ratio was ensured to be kept at 1.67:1. Appealing results are reported for the encapsulated product which was prepared by Method (a2). Method (a) was done at three different molar ratios of PO 4 3- :CO 3 2- and best result was obtained for that utilized 2.003:1 molar ratio (Method (a2).). It produced 98.67% of encapsulation efficiency and 2.9522mg/g of drug loading capacity. Release kinetics was studied at a range of pH values; the lower the pH of the medium the higher is the drug release. For instance, when considering the product which exhibited high encapsulation efficiency and high drug loading capacity, at pH3.5 during the first 8h it elicited about 13% of release, at pH5.0 about 8% release while at pH6.0 it was just 2.5%. During the 24-hour span, pH3.5 exhibited about 23.8%, at pH5.0 approximately 9% with an increasing trend of release and at pH6.0 showed a value just above 2.5%. As such, acidity of the cancerous

  2. Bone integration capability of nanopolymorphic crystalline hydroxyapatite coated on titanium implants

    PubMed Central

    Yamada, Masahiro; Ueno, Takeshi; Tsukimura, Naoki; Ikeda, Takayuki; Nakagawa, Kaori; Hori, Norio; Suzuki, Takeo; Ogawa, Takahiro

    2012-01-01

    The mechanism by which hydroxyapatite (HA)-coated titanium promotes bone–implant integration is largely unknown. Furthermore, refining the fabrication of nano-structured HA to the level applicable to the mass production process for titanium implants is challenging. This study reports successful creation of nanopolymorphic crystalline HA on microroughened titanium surfaces using a combination of flame spray and low-temperature calcination and tests its biological capability to enhance bone–implant integration. Sandblasted microroughened titanium implants and sandblasted + HA-coated titanium implants were subjected to biomechanical and histomorphometric analyses in a rat model. The HA was 55% crystallized and consisted of nanoscale needle-like architectures developed in various diameters, lengths, and orientations, which resulted in a 70% increase in surface area compared to noncoated microroughened surfaces. The HA was free from impurity contaminants, with a calcium/phosphorus ratio of 1.66 being equivalent to that of stoichiometric HA. As compared to microroughened implants, HA-coated implants increased the strength of bone–implant integration consistently at both early and late stages of healing. HA-coated implants showed an increased percentage of bone–implant contact and bone volume within 50 μm proximity of the implant surface, as well as a remarkably reduced percentage of soft tissue intervention between bone and the implant surface. In contrast, bone volume outside the 50 μm border was lower around HA-coated implants. Thus, this study demonstrated that the addition of pure nanopolymorphic crystalline HA to microroughened titanium not only accelerates but also enhances the level of bone–implant integration and identified the specific tissue morphogenesis parameters modulated by HA coating. In particular, the nanocrystalline HA was proven to be drastic in increasing osteoconductivity and inhibiting soft tissue infiltration, but the effect was

  3. Nano-Ag-loaded hydroxyapatite coatings on titanium surfaces by electrochemical deposition

    PubMed Central

    Lu, Xiong; Zhang, Bailin; Wang, Yingbo; Zhou, Xianli; Weng, Jie; Qu, Shuxin; Feng, Bo; Watari, Fumio; Ding, Yonghui; Leng, Yang

    2011-01-01

    Hydroxyapatite (HA) coatings on titanium (Ti) substrates have attracted much attention owing to the combination of good mechanical properties of Ti and superior biocompatibility of HA. Incorporating silver (Ag) into HA coatings is an effective method to impart the coatings with antibacterial properties. However, the uniform distribution of Ag is still a challenge and Ag particles in the coatings are easy to agglomerate, which in turn affects the applications of the coatings. In this study, we employed pulsed electrochemical deposition to co-deposit HA and Ag simultaneously, which realized the uniform distribution of Ag particles in the coatings. This method was based on the use of a well-designed electrolyte containing Ag ions, calcium ions and l-cysteine, in which cysteine acted as the coordination agent to stabilize Ag ions. The antibacterial and cell culture tests were used to evaluate the antibacterial properties and biocompatibility of HA/Ag composite coatings, respectively. The results indicated the as-prepared coatings had good antibacterial properties and biocompatibility. However, an appropriate silver content should be chosen to balance the biocompatibility and antibacterial properties. Heat treatments promoted the adhesive strength and enhanced the biocompatibility without sacrificing the antibacterial properties of the HA/Ag coatings. In summary, this study provided an alternative method to prepare bioactive surfaces with bactericidal ability for biomedical devices. PMID:20880853

  4. Evaluation of nanoparticles of hydroxyapatite and MWCNT’s in scaffolds of poly lactic acid

    NASA Astrophysics Data System (ADS)

    Román-Doval, R.; Morales-Corona, J.; Olayo, R.; Escamilla-Rivera, V.; Uribe-Ramírez, M.; Ortega-López, M.

    2016-12-01

    In the tissue engineering, the cytotoxicity test is an important part of the biomaterials performance. This research reports the production and characterization of polylactic acid (PLA)-supported hydroxyapatite (HA) and multiwalled carbon nanotubes (MWCNT) scaffolds as a bone graft material. Samples containing different HA/MWCNT wt% ratios were prepared by electrospinning. The obtained samples displayed valuable characteristics for the cell adhesion because of their porous-spongy bone-like morphology. The Fourier transforms infrared and Raman analyses indicated no chemical interaction of HA and MWCNT with PLA molecules, but they appear to be only embedded into the PLA fibers. As indicated by x-ray diffraction, crystalline HA and MWCNT’s are supported in the amorphous PLA fibers. Under tensile stress, scaffolds display a Young’s Modulus about 86 MPa, whilst the scaffolds resistance increases with the HA-MWCNT’s ratio. However, the MTS in-vitro assays using the hFOB 1.19 (ATCC CRL-11372) cells, for cell exposure time of 24 and 48 h, revealed that viability reduces for HA-MWCNT’s ratio values over 25 wt%. Our results suggest that a maximum HA/MWCNT’s ratio of 19:1 could be acceptable for cell proliferation while maintaining HA at 200 mg.

  5. RGO/AuNR/HA-5FU nanocomposite with multi-stage release behavior and efficient antitumor activity for synergistic therapy.

    PubMed

    Yang, Ying; Wang, Yunlong; Zhu, Manzhou; Chen, Yan; Xiao, Yazhong; Shen, Yuhua; Xie, Anjian

    2017-05-02

    A reduced graphene oxide (RGO)/gold nanorod (AuNR)/hydroxyapatite (HA) nanocomposite was designed and successfully synthesized for the first time. An anticancer drug, 5-fluorouracil (5FU), was chosen as a model drug to be loaded in RGO/AuNR/HA. The fabricated RGO/AuNR/HA-5FU showed robust, selective targeting and penetrating efficiency against HeLa cells due to the good compatibility and nontoxicity of HA, and showed excellent synergetic antitumor effects through combined chemotherapy (CT) by 5FU and photothermal therapy (PTT) by both RGO and AuNRs under near-infrared (NIR) laser irradiation. More importantly, this synergistic dual therapy based on RGO/AuNR/HA can also minimize side effects in normal cells and exhibits greater antitumor activity because of a multi-stage drug release ability triggered by the pH sensitivity of HA in the first stage and the combined photothermal conversion capabilities of RGO and AuNRs by means of the NIR laser irradiation in the second stage. This study suggests that the novel RGO/AuNR/HA multi-stage drug delivery system may represent a promising potential application of multifunctional composite materials in the biomedical field.

  6. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces.

    PubMed

    Wijesinghe, W P S L; Mantilaka, M M M G P G; Chathuranga Senarathna, K G; Herath, H M T U; Premachandra, T N; Ranasinghe, C S K; Rajapakse, R P V J; Rajapakse, R M G; Edirisinghe, Mohan; Mahalingam, S; Bandara, I M C C D; Singh, Sanjleena

    2016-06-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO2 thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. A biodegradable AZ91 magnesium alloy coated with a thin nanostructured hydroxyapatite for improving the corrosion resistance.

    PubMed

    Mukhametkaliyev, T M; Surmeneva, M A; Vladescu, A; Cotrut, C M; Braic, M; Dinu, M; Vranceanu, M D; Pana, I; Mueller, M; Surmenev, R A

    2017-06-01

    The main aim of this study was to investigate the properties of an AZ91 alloy coated with nanostructured hydroxyapatite (HA) prepared by radio frequency (RF) magnetron sputtering. The bioactivity and biomineralization of the AZ91 magnesium alloy coated with HA were investigated in simulated body fluid (SBF) via an in vitro test. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) analyses were performed. The samples were immersed in SBF to study the ability of the surface to promote the formation of an apatite layer as well as corrosion resistance and mass change of the HA-coated AZ91 alloy. Electrochemical tests were performed to estimate the corrosion behaviour of HA-coated and uncoated samples. The results revealed the capability of the HA coating to significantly improve the corrosion resistance of the uncoated AZ91 alloy. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Fabrication of hydroxyapatite-poly(epsilon-caprolactone) scaffolds by a combination of the extrusion and bi-axial lamination processes.

    PubMed

    Sun, Jong-Jae; Bae, Chang-Jun; Koh, Young-Hag; Kim, Hyoun-Ee; Kim, Hae-Won

    2007-06-01

    Hydroxyapatite (HA)/poly(epsilon-caprolactone) (PCL) composite scaffolds were fabricated using a combination of the extrusion and bi-axial lamination processes. Firstly, HA/PCL composites with various HA contents (0, 50, 60, 70 wt%) were prepared by mixing the HA powders and the molten PCL at 100 degrees C and then extruded through an orifice with dimensions of 600 x 600 microm to produce HA/PCL composite fibers. Isobutyl methacrylate (IBMA) polymer fiber was also prepared in a similar manner for use as a fugitive material. The 3-D scaffold was then produced by the bi-axial lamination of the HA/PCL and IBMA fibers, followed by solvent leaching to remove the IBMA. It was observed that the HA/PCL composites had a superior elastic modulus and biological properties, as compared to the pure PCL. The fabricated HA/PCL scaffold showed a controlled pore structure (porosity of approximately 49% and pore size of approximately 512 microm) and excellent welding between the HA/PCL fibers, as well as a high compressive strength of approximately 7.8 MPa.

  9. Coupling system to a microsphere cavity

    NASA Technical Reports Server (NTRS)

    Iltchenko, Vladimir (Inventor); Maleki, Lute (Inventor); Yao, Steve (Inventor); Wu, Chi (Inventor)

    2002-01-01

    A system of coupling optical energy in a waveguide mode, into a resonator that operates in a whispering gallery mode. A first part of the operation uses a fiber in its waveguide mode to couple information into a resonator e.g. a microsphere. The fiber is cleaved at an angle .PHI. which causes total internal reflection within the fiber. The energy in the fiber then forms an evanescent field and a microsphere is placed in the area of the evanescent field. If the microsphere resonance is resonant with energy in the fiber, then the information in the fiber is effectively transferred to the microsphere.

  10. Osteoinductive silk fibroin/titanium dioxide/hydroxyapatite hybrid scaffold for bone tissue engineering.

    PubMed

    Kim, Jung-Ho; Kim, Dong-Kyu; Lee, Ok Joo; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Lee, Jun Ho; Park, Chan Hum

    2016-01-01

    The present study demonstrated the fabrication that incorporation of titanium isopropoxide (TiO2) and hydroxyapatite (HA) nanoparticles into the silk fibroin (SF) scaffolds. In this process, we prepared TiO2 nanoparticles using sol-gel synthesis and the porous structure was developed by salt-leaching process. Homogeneous distribution of TiO2 and HA nanoparticles were confirmed by images of VP-FE-SEM and those equipped with energy dispersive X-ray spectrometer. Structural characteristics of the porous SF/TiO2/HA hybrid scaffold were also determined using FTIR analysis and X-ray diffractometer. In this study, the porous SF/TiO2/HA hybrid scaffold showed similar porosity, enhanced mechanical property, but decreased water binding abilities, compared with the porous SF scaffold. For evaluation of the osteogenic differentiation of rat bone marrow mesenchymal stem cells, alkaline phosphatase activity and osteogenic gene expression were employed. Our results revealed that the porous SF/TiO2/HA hybrid scaffold had improved osteoinductivity compared with the porous SF scaffold. These results suggest that the osteogenic property as well as mechanical property of the porous SF/TiO2/HA hybrid scaffold could be better than the porous SF scaffold. Therefore, the porous SF/TiO2/HA hybrid scaffold may be a good promising biomaterial for bone tissue engineering application. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Nano-scale characterization of nano-hydroxyapatite incorporated chitosan particles for bone repair.

    PubMed

    Gaihre, Bipin; Uswatta, Suren; Jayasuriya, Ambalangodage C

    2018-05-01

    In this study, injectable porous spherical particles were fabricated using chitosan (CS) biopolymer, sodium tripolyphosphate (TPP), and nano-hydroxyapatite (nHA). TPP was primarily used as an ionic crosslinker to crosslink 2% (w/v) CS droplets. 2% (w/v) nHA was used to prepare nHA incorporated particles. The surface morphological properties and nanomechanical properties such as topography, deformation, adhesion, and dissipation of CS particles with and without nHA were studied using contact mode and peakforce quantitative nanomechanical property mapping mode in atomic force microscopy. The nHA spots have higher density than CS which leads to higher forces acting on the probe tip and higher energy dissipation to lift the tip from nHA areas. The cumulative release data showed that about 87% of total BMP-2 encapsulated within the particles was released by third week of experiment period. Degradation study was conducted to understand how the particles degradation occurs in the presence of phosphate buffered saline with continues shaking in an incubator at 37° C. In addition, BMP-2 release from the 2% nHA/CS particles was studied over a three weeks period and found that BMP-2 release was governed by the simple diffusion rather than the degradation of particles. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Development and characterization of porous silver-incorporated hydroxyapatite ceramic for separation and elimination of microorganisms.

    PubMed

    Yang, Lei; Ning, Xiaoshan; Xiao, Qunfang; Chen, Kexin; Zhou, Heping

    2007-04-01

    A novel filter material for separating and eliminating microorganisms in water and gas was fabricated by incorporating silver ions into porous hydroxyapatite (HA) ceramics prepared by a starch additive technique. The porous ceramics reveal a microstructure of both large and small pores. Microorganism separating and eliminating properties of the porous silver-incorporated HA ceramics (PHA-Ag) were investigated by bacterial and viral filtration tests. The PHA-Ag demonstrated excellent separating and antibacterial effects on Escherichia coli and the mechanisms were studied. Adsorption of bacterial cells to the HA and the barricading effect of small pores contribute to the separating property of PHA-Ag, while the Ag+ ions equip the ceramics with antibacterial property. Furthermore, the PHA-Ag exhibited an observable virus-eliminating property and its probable mechanism was also discussed. (c) 2006 Wiley Periodicals, Inc.

  13. Nano-hydroxyapatite/β-CD/chitosan nanocomposite for potential applications in bone tissue engineering.

    PubMed

    Shakir, Mohammad; Jolly, Reshma; Khan, Mohd Shoeb; Rauf, Ahmar; Kazmi, Shadab

    2016-12-01

    Herein, we report the synthesis of a novel tri-component nanocomposite system incorporating β-cyclodextrin (β-CD) with nano-hydroxyapatite (n-HA) and chitosan (CS), (n-HA/β-CD/CS) at three different temperatures via co-precipitation method. The chemical interactions and surface morphology have been evaluated by TEM, SEM and AFM techniques revealing the agglomerated nanoparticles in CS/n-HA-HA binary system whereas the ternary systems produced needle shaped nanoparticles dispersed homogeneously at low temperature with more porous and rougher surface. The addition of β-CD in CS/n-HA at low temperature decreased the particle size and raised the thermal stability as compared to CS/n-HA. The comparative hemolytic, protein adsorption and platelet adhesion studies confirmed the better hemocompatibility of n-HA/β-CD/CS-(RT,HT,LT) nanocomposites relative to CS/n-HA. The cell viability has been evaluated in vitro using MG-63 cell line which revealed superior non toxicity of n-HA/β-CD/CS-LT nanocomposite in comparison to n-HA/β-CD/CS-(RT,HT) and CS/n-HA nanocomposites. Thus it may be concluded that the orchestrated organic/inorganic n-HA/β-CD/CS-(RT,HT,LT) nanocomposites exhibited relatively higher cell viability of human osteoblast cells, stimulated greater osteogenesis, controlled biodegradation, enhanced antibacterial activity with excellent in-vitro biomineralization and remarkable mechanical parameters as compared to CS/n-HA nanocomposite and thus may provide opportunities for potential use as an alternative biomaterial for Bone tissue engineering applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Preparation, characterization and properties of nano-hydroxyapatite/polypropylene carbonate biocomposite.

    PubMed

    Liao, Jianguo; Li, Yanqun; Zou, Qin; Duan, Xingze; Yang, Zhengpeng; Xie, Yufen; Liu, Haohuai

    2016-06-01

    The combination of nano-hydroxyapatite (n-HA) and polypropylene carbonate (PPC) was used to make a composite materials by a coprecipitation method. The physical and chemical properties of the composite were tested. Scanning electron microscope (SEM) observation indicated that the biomimetic n-HA crystals were uniformly distributed in the polymer matrix. As the n-HA content increased in the composite, the fracture mechanism of the composites changes from gliding fracture to gliding and brittle fracture. Furthermore, the chemical interaction between inorganic n-HA and polypropylene carbonate was also investigated and discussed in detail. The hydrogen bonds might be formed between -OH/CO3(2-) of n-HA crystal and the ester group (-COO-) of PPC. The tensile strength of n-HA/PPC (40/60) was similar to that of the cancellous bone, and reached ca 58 MPa. The osteoblasts were cultured for up to 7 days, and then the adhesion and proliferation of osteoblasts were measured by Methyl thiazolyl tetrazolium (MTT) colorimetry assay and SEM. The cells proliferated, grew normally in fusiform shape and well attached. The in vitro test confirmed that the n-HA/PPC composites were biocompatible and showed undetectable negative effect on osteoblasts. In vivo implantation of the composite in New Zealand white rabbits was performed. It can stimulate the growth of a new bone, and at the same time the material begins to degrade. These results suggested that the composite may be suitable for the reparation or replacement of bone defects and possessed the potential for clinical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. X-ray diffraction analysis of hydroxyapatite-coated in different plasma gas atmosphere on Ti and Ti-6Al-4V

    PubMed Central

    Kotian, Ravindra; Rao, P. Prasad; Madhyastha, Prashanthi

    2017-01-01

    Objective: The aim is to study the effect of plasma working gas on composition, crystallinity, and microstructure of hydroxyapatite (HA) coated on Ti and Ti-6Al-4V metal substrates. Materials and Methods: Ti and Ti-6Al-4V metal substrates were coated with HA by plasma spray using four plasma gas atmospheres of argon, argon/hydrogen, nitrogen, and nitrogen/hydrogen. The degree of crystallinity, the phases present, and microstructure of HA coating were characterized using X-ray diffraction and scanning electron microscopy. Results: Variation in crystallinity and the microstructure of HA coating on plasma gas atmosphere was observed. Micro-cracks due to thermal stresses and shift in the 2θ angle of HA compared to feedstock was seen. Conclusion: Plasma gas atmosphere has a significant influence on composition, crystallinity, and micro-cracks of HA-coated dental implants. PMID:29279668

  16. Size effect of optical silica microsphere pressure sensors

    NASA Astrophysics Data System (ADS)

    Jiao, Xinbing; Hao, Ruirui; Pan, Qian; Zhao, Xinwei; Bai, Xue

    2018-07-01

    Two types of optical pressure sensors with silica microspheres are proposed. The size effect of optical silica microsphere pressure sensors is studied by using a single-wavelength laser beam and polarimeters. The silica microspheres with diameters of 1.0 μm, 1.5 μm and 2.0 μm are prepared on garnet substrates by a self-assembly method. The pressure and the optical properties of the silica microspheres are measured by a resistance strain sensor and Thorlabs Stokes polarimeters as a function of the external direct current (DC) voltage. The optical silica microsphere sensor in transmission mode is suitable for pressure measuring. The results show that the pressure increases, while the diameter of the silica microspheres decreases. The maximum internal pressure can reach up to 7.3 × 107 Pa when the diameter of the silica microspheres is 1.0 μm.

  17. Laminated electrospun nHA/PHB-composite scaffolds mimicking bone extracellular matrix for bone tissue engineering.

    PubMed

    Chen, Zhuoyue; Song, Yue; Zhang, Jing; Liu, Wei; Cui, Jihong; Li, Hongmin; Chen, Fulin

    2017-03-01

    Electrospinning is an effective means to generate nano- to micro-scale polymer fibers resembling native extracellular matrix for tissue engineering. However, a major problem of electrospun materials is that limited pore size and porosity may prevent adequate cellular infiltration and tissue ingrowth. In this study, we first prepared thin layers of hydroxyapatite nanoparticle (nHA)/poly-hydroxybutyrate (PHB) via electrospinning. We then laminated the nHA/PHB thin layers to obtain a scaffold for cell seeding and bone tissue engineering. The results demonstrated that the laminated scaffold possessed optimized cell-loading capacity. Bone marrow mesenchymal stem cells (MSCs) exhibited better adherence, proliferation and osteogenic phenotypes on nHA/PHB scaffolds than on PHB scaffolds. Thereafter, we seeded MSCs onto nHA/PHB scaffolds to fabricate bone grafts. Histological observation showed osteoid tissue formation throughout the scaffold, with most of the scaffold absorbed in the specimens 2months after implantation, and blood vessels ingrowth into the graft could be observed in the graft. We concluded that electrospun and laminated nanoscaled biocomposite scaffolds hold great therapeutic potential for bone regeneration. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Preparation and Characterization of Silica Aerogel Microspheres

    PubMed Central

    Chen, Qifeng; Wang, Hui; Sun, Luyi

    2017-01-01

    Silica aerogel microspheres based on alkali silica sol were synthesized using the emulsion method. The experimental results revealed that the silica aerogel microspheres (4–20 µm in diameter) were mesoporous solids with an average pore diameter ranging from 6 to 35 nm. The tapping densities and specific surface areas of the aerogel microspheres are in the range of 0.112–0.287 g/cm3 and 207.5–660.6 m2/g, respectively. The diameter of the silica aerogel microspheres could be tailored by varying the processing conditions including agitation rate, water/oil ratio, mass ratio of Span 80: Tween 80, and emulsifier concentration. The effects of these parameters on the morphology and textural properties of the synthesized silica aerogel microspheres were systematically investigated. Such silica aerogel microspheres can be used to prepare large-scale silica aerogels at an ambient pressure for applications in separation and high efficiency catalysis, which requires features of high porosity and easy fill and recovery. PMID:28772795

  19. Preparation and Characterization of Silica Aerogel Microspheres.

    PubMed

    Chen, Qifeng; Wang, Hui; Sun, Luyi

    2017-04-20

    Silica aerogel microspheres based on alkali silica sol were synthesized using the emulsion method. The experimental results revealed that the silica aerogel microspheres (4-20 µm in diameter) were mesoporous solids with an average pore diameter ranging from 6 to 35 nm. The tapping densities and specific surface areas of the aerogel microspheres are in the range of 0.112-0.287 g/cm³ and 207.5-660.6 m²/g, respectively. The diameter of the silica aerogel microspheres could be tailored by varying the processing conditions including agitation rate, water/oil ratio, mass ratio of Span 80: Tween 80, and emulsifier concentration. The effects of these parameters on the morphology and textural properties of the synthesized silica aerogel microspheres were systematically investigated. Such silica aerogel microspheres can be used to prepare large-scale silica aerogels at an ambient pressure for applications in separation and high efficiency catalysis, which requires features of high porosity and easy fill and recovery.

  20. Optimally designed collagen/polycaprolactone biocomposites supplemented with controlled release of HA/TCP/rhBMP-2 and HA/TCP/PRP for hard tissue regeneration.

    PubMed

    Kim, WonJin; Jang, Chul Ho; Kim, GeunHyung

    2017-09-01

    Collagen has been widely used as a very promising material to regenerate various tissues. It is a chief component of the extracellular matrix, and encourages various biological effects conducive to tissue regeneration. However, poor mechanical stability, low processability, and high level of water absorption can lead to impaired control of growth factor release and have impeded the use of collagen as a functional biomedical scaffold. Here, to overcome the shortcomings of collagen scaffolds, we have additively manufactured collagen/polycaprolactone (PCL) biocomposites supplemented with a bioceramic (hydroxyapatite (HA)/β-tricalcium-phosphate (TCP)) and two growth factors (recombinant human bone morphogenetic protein-2 [rhBMP-2] and platelet-rich plasma [PRP]). Various weight fractions of PCL in the collagen/PCL composites were manipulated to select optimal growth factor release and highly active cellular responses. After the optimal concentration of PCL in the collagen/PCL scaffold was determined, biocomposites supplemented with bioceramic/growth-factors were fabricated. Continuously released growth factors were assumed to increase the in vitro cellular activities of the osteoblast-like cells (MG63) cultured on the biocomposites. In vitro cellular responses, including osteogenic activities, were examined, and results showed that compared to the HA/TCP/rhBMP-2 supplemented scaffold the HA/TCP/PRP biocomposites provide significantly high cellular activities (cell proliferation: >1.3-fold) and mineralization (calcium deposition: >1.4-fold, osteocalcin: >2.6-fold) sufficient for regenerating bone tissue. Copyright © 2017. Published by Elsevier B.V.

  1. Coatings of needle/stripe-like fluoridated hydroxyapatite on H2O2-treated carbon/carbon composites prepared by induction heating and hydrothermal methods

    NASA Astrophysics Data System (ADS)

    Xiong, Xin-Bo; Huang, Jian-Feng; Zeng, Xie-Rong; Liang, Ping; Zou, Ji-Zhao

    2012-06-01

    A hydroxyapatite (HA) coating was achieved on H2O2-treated carbon/carbon (C/C) composite through hydrothermally treating and induction heating deposited CaHPO4 coating in an ammonia solution under ultrasonic water bath. Then, this HA coating was placed in a NH4F solution and hydrothermally treated again to fabricate fluorinated hydroxyapatite (FHA) coatings for 24 h at 353, 373, 393 and 413 K, respectively. The structure, morphology and chemical composition of the HA and FHA coatings were characterized by SEM, XRD, EDS and FTIR, and the adhesiveness and chemical stability of these FHA coatings were examined by a scratch test and an immersion test, respectively. The results showed that the as-prepared FHA coatings contained needle-like or stripe-like crystals, different from those of the HA coating. As the fluoridation temperature rose, the adhesiveness of the FHA coating first increased from 34.8 to 40.9 N at a temperature between 353 and 393 K, and then decreased to 24.2 N at 413 K, while the dissolution rate of the FHA coating decreased steadily. The reasons for the property variation of the FHA coatings were proposed by analyzing the morphology, composition and structure of the coatings.

  2. Integrated Cryogenic Experiment (ICE) microsphere investigation

    NASA Technical Reports Server (NTRS)

    Spradley, I.; Read, D.

    1989-01-01

    The main objective is to determine the performance of microsphere insulation in a 0-g environment and compare its performance to reference insulations such as multilayer insulation. The Lockheed Helium Extended-Life Dewar (HELD) is used to provide superfluid-helium cold sink for the experiment. The use of HELD allows the low-g dynamic properties of Passive Orbital Disconnect Struts (PODS) to be characterized and provides a flight demonstration of the PODS system. The thermal performance of microspheres in 1 and 0 g was predicted, a flight experiment was designed to determine microsphere thermal performance, and the interface was also designed between the experimental package and the shuttle through HELD and the Hitchhiker-M carrier. A single test cell was designed and fabricated. The cell was filled with uncoated glass microspheres and tested with a liquid-nitrogen cold sink. The data were found to agree with predictions of microsphere performance in 1 g.

  3. Development of electrophoretically deposited hydroxyapatite coatings on anodized nanotubular TiO2 structures: Corrosion and sintering temperature

    NASA Astrophysics Data System (ADS)

    Goudarzi, Mona; Batmanghelich, Farhad; Afshar, Abdollah; Dolati, Abolghasem; Mortazavi, Golsa

    2014-05-01

    Hydroxyapatite (HA) coatings in and onto anodized TiO2 nanotube arrays were presented and prepared by electrophoretic deposition technique (EPD). Coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). EPD proved to be an innovative and versatile technique to coat HA on and into nanotubular structures of TiO2 with enhanced adhesion between nanotubes and HA particles provided by mechanical interlocking. After EPD of HA on TiO2 layer, samples were sintered at 400 °C, 600 °C and 800 °C for 2 h in an Ar atmosphere. Effect of EPD processing parameters on thickness of the deposits and rate of deposition was elucidated for HA coatings on the nanotubular TiO2 structures. It was shown that higher applied voltages increase deposition rate and thickness of the coatings. Potentiodynamic polarization measurements proved corrosion protection caused by both HA coating and nanotubular TiO2 structure in simulated body fluid (SBF). Effect of sintering temperature on adhesion strength of HA coatings on TiO2 nanotubes and their composition were also studied.

  4. Interconnected porous hydroxyapatite ceramics for bone tissue engineering

    PubMed Central

    Yoshikawa, Hideki; Tamai, Noriyuki; Murase, Tsuyoshi; Myoui, Akira

    2008-01-01

    Several porous calcium hydroxyapatite (HA) ceramics have been used clinically as bone substitutes, but most of them possessed few interpore connections, resulting in pathological fracture probably due to poor bone formation within the substitute. We recently developed a fully interconnected porous HA ceramic (IP-CHA) by adopting the ‘foam-gel’ technique. The IP-CHA had a three-dimensional structure with spherical pores of uniform size (average 150 μm, porosity 75%), which were interconnected by window-like holes (average diameter 40 μm), and also demonstrated adequate compression strength (10–12 MPa). In animal experiments, the IP-CHA showed superior osteoconduction, with the majority of pores filled with newly formed bone. The interconnected porous structure facilitates bone tissue engineering by allowing the introduction of mesenchymal cells, osteotropic agents such as bone morphogenetic protein or vasculature into the pores. Clinically, we have applied the IP-CHA to treat various bony defects in orthopaedic surgery, and radiographic examinations demonstrated that grafted IP-CHA gained radiopacity more quickly than the synthetic HA in clinical use previously. We review the accumulated data on bone tissue engineering using the novel scaffold and on clinical application in the orthopaedic field. PMID:19106069

  5. Microstructural characteristics and biocompatibility of a Type-B carbonated hydroxyapatite coating deposited on NiTi shape memory alloy.

    PubMed

    Chu, Chenglin; Hu, T; Yin, L H; Pu, Y P; Dong, Y S; Lin, P H; Chung, C Y; Yeung, K W K; Chu, P K

    2009-01-01

    Microstructural characteristics and biocompatibility of a Type-B carbonated hydroxyapatite (HA) coating prepared on NiTi SMA by biomimetic deposition were characterized using XRD, SEM, XPS, FTIR and in vitro studies including hemolysis test, MTT cytotoxicity test and fibroblasts cytocompatibility test. It is found CO(3)(2-) groups were present as substitution of PO(4)(3-) anions in HA crystal lattice due to Type-B carbonate. The growth of Type-B carbonated HA coating in SBF containing HCO(3)(-) ions is stable during all periods of biomimetic deposition. The carbonated HA coating has better blood compatibility than the chemically-polished NiTi SMA. There was a good cell adhesion to this HA coating surface and cell proliferation in the vicinity of the coating was better than that for the chemically-polished NiTi SMA. Thus biomimetic deposition of this carbonated HA coating is a promising way to improve the biocompatibility of NiTi SMA for implant applications.

  6. Micro-/Nano- sized hydroxyapatite directs differentiation of rat bone marrow derived mesenchymal stem cells towards an osteoblast lineage

    NASA Astrophysics Data System (ADS)

    Huang, Yan; Zhou, Gang; Zheng, Lisha; Liu, Haifeng; Niu, Xufeng; Fan, Yubo

    2012-03-01

    Regenerative medicine consisting of cells and materials provides a new way for the repair and regeneration of tissues and organs. Nano-biomaterials are highlighted due to their advantageous features compared with conventional micro-materials. The aim of this study is to investigate the effects of micro-/nano- sized hydroxyapatite (μ/n-HA) on the osteogenic differentiation of rat bone marrow derived mesenchymal stem cells (rBMSCs). μ/n-HA were prepared by a microwave synthesizer and precipitation method, respectively. Different sizes of μ/n-HA were characterized by IR, XRD, SEM, TEM and co-cultured with rBMSCs. It was shown that rBMSCs expressed higher levels of osteoblast-related markers by n-HA than μ-HA stimulation. The size of HA is an important factor for affecting the osteogenic differentiation of rBMSCs. This provides a new avenue for mechanistic studies of stem cell differentiation and a new approach to obtain more committed differentiated cells.

  7. Melt spinning of poly(lactic acid) and hydroxyapatite composite fibers: influence of the filler content on the fiber properties.

    PubMed

    Persson, Maria; Lorite, Gabriela S; Cho, Sung-Woo; Tuukkanen, Juha; Skrifvars, Mikael

    2013-08-14

    Composite fibers from poly(lactic acid) (PLA) and hydroxyapatite (HA) particles were prepared using melt spinning. Different loading concentrations of HA particles (i.e., 5, 10, 15, and 20 wt %) in the PLA fibers and solid-state draw ratios (SSDRs) were evaluated in order to investigate their influence on the fibers' morphology and thermal and mechanical properties. A scanning electron microscopy investigation indicated that the HA particles were homogeneously distributed in the PLA fibers. It was also revealed by atomic force microscopy and Fourier transform infrared spectroscopy that HA particles were located on the fiber surface, which is of importance for their intended application in biomedical textiles. Our results also suggest that the mechanical properties were independent of the loading concentration of the HA particles and that the SSDR played an important role in improving the mechanical properties of the composite fibers.

  8. Hydroxyapatite coating on PEEK implants: biomechanical and histological study in a rabbit model

    PubMed Central

    Durham, John W.; Montelongo, Sergio A.; Ong, Joo L.; Guda, Teja; Allen, Matthew J.; Rabiei, Afsaneh

    2016-01-01

    A bioactive two-layer coating consisting of hydroxyapatite (HA) and yttria-stabilized zirconia (YSZ) was investigated on cylindrical polyether ether ketone (PEEK) implants using ion beam assisted deposition (IBAD). Post-deposition heat treatments via variable frequency microwave annealing with and without subsequent autoclaving were used to crystallize the as-deposited amorphous HA layer. Microstructural analysis, performed by TEM and EDS, showed that these methods were capable of crystallizing HA coating on PEEK. The in vivo response to cylindrical PEEK samples with and without coating was studied by implanting uncoated PEEK and coated PEEK implants in the lateral femoral condyle of 18 rabbits. Animals were studied in two groups 9 for observation at 6 or 18 weeks post surgery. MicroCT analysis, histology, and mechanical pull-out tests were performed to determine the effect of the coating on osseointegration. The heat-treated HA/YSZ coatings showed improved implant fixation as well as higher bone regeneration and bone-implant contact area compared to uncoated PEEK. The study offers a novel method to coat PEEK implants with improved osseointegration. PMID:27524073

  9. High-density, microsphere-based fiber optic DNA microarrays.

    PubMed

    Epstein, Jason R; Leung, Amy P K; Lee, Kyong Hoon; Walt, David R

    2003-05-01

    A high-density fiber optic DNA microarray has been developed consisting of oligonucleotide-functionalized, 3.1-microm-diameter microspheres randomly distributed on the etched face of an imaging fiber bundle. The fiber bundles are comprised of 6000-50000 fused optical fibers and each fiber terminates with an etched well. The microwell array is capable of housing complementary-sized microspheres, each containing thousands of copies of a unique oligonucleotide probe sequence. The array fabrication process results in random microsphere placement. Determining the position of microspheres in the random array requires an optical encoding scheme. This array platform provides many advantages over other array formats. The microsphere-stock suspension concentration added to the etched fiber can be controlled to provide inherent sensor redundancy. Examining identical microspheres has a beneficial effect on the signal-to-noise ratio. As other sequences of interest are discovered, new microsphere sensing elements can be added to existing microsphere pools and new arrays can be fabricated incorporating the new sequences without altering the existing detection capabilities. These microarrays contain the smallest feature sizes (3 microm) of any DNA array, allowing interrogation of extremely small sample volumes. Reducing the feature size results in higher local target molecule concentrations, creating rapid and highly sensitive assays. The microsphere array platform is also flexible in its applications; research has included DNA-protein interaction profiles, microbial strain differentiation, and non-labeled target interrogation with molecular beacons. Fiber optic microsphere-based DNA microarrays have a simple fabrication protocol enabling their expansion into other applications, such as single cell-based assays.

  10. The differential regulation of osteoblast and osteoclast activity by surface topography of hydroxyapatite coatings.

    PubMed

    Costa, Daniel O; Prowse, Paul D H; Chrones, Tom; Sims, Stephen M; Hamilton, Douglas W; Rizkalla, Amin S; Dixon, S Jeffrey

    2013-10-01

    The behavior of bone cells is influenced by the surface chemistry and topography of implants and scaffolds. Our purpose was to investigate how the topography of biomimetic hydroxyapatite (HA) coatings influences the attachment and differentiation of osteoblasts, and the resorptive activity of osteoclasts. Using strategies reported previously, we directly controlled the surface topography of HA coatings on polycaprolactone discs. Osteoblasts and osteoclasts were incubated on HA coatings having distinct isotropic topographies with submicrometer and micro-scale features. Osteoblast attachment and differentiation were greater on more complex, micro-rough HA surfaces (Ra ~2 μm) than on smoother topographies (Ra ~1 μm). In contrast, activity of the osteoclast marker tartrate-resistant acid phosphatase was greater on smoother than on micro-rough surfaces. Furthermore, scanning electron microscopy revealed the presence of resorption lacunae exclusively on smoother HA coatings. Inhibition of resorption on micro-rough surfaces was associated with disruption of filamentous actin sealing zones. In conclusion, HA coatings can be prepared with distinct topographies, which differentially regulate responses of osteoblasts, as well as osteoclastic activity and hence susceptibility to resorption. Thus, it may be possible to design HA coatings that induce optimal rates of bone formation and degradation specifically tailored for different applications in orthopedics and dentistry. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Fabrication and physico-mechanical properties of thin magnetron sputter deposited silver-containing hydroxyapatite films

    NASA Astrophysics Data System (ADS)

    Ivanova, A. A.; Surmeneva, M. A.; Tyurin, A. I.; Pirozhkova, T. S.; Shuvarin, I. A.; Prymak, O.; Epple, M.; Chaikina, M. V.; Surmenev, R. A.

    2016-01-01

    As a measure of the prevention of implant associated infections, a number of strategies have been recently applied. Silver-containing materials possessing antibacterial activity as expected might have wide applications in orthopedics and dentistry. The present work focuses on the physico-chemical characterization of silver-containing hydroxyapatite (Ag-HA) coating obtained by radio frequency (RF) magnetron sputtering. Mechanochemically synthesized Ag-HA powder (Ca10⿿xAgx(PO4)6(OH)2⿿x, x = 1.5) was used as a precursor for sputtering target preparation. Morphology, composition, crystallinity, physico-mechanical features (Young's modulus and nanohardness) of the deposited Ag-HA coatings were investigated. The sputtering of the nanostructured multicomponent target at the applied process conditions allowed to deposit crystalline Ag-HA coating which was confirmed by XRD and FTIR data. The SEM results revealed the formation of the coating with the grain morphology and columnar cross-section structure. The EDX analysis confirmed that Ag-HA coating contained Ca, P, O and Ag with the Ca/P ratio of 1.6 ± 0.1. The evolution of the mechanical properties allowed to conclude that addition of silver to HA film caused increase of the coating nanohardness and elastic modulus compared with those of pure HA thin films deposited under the same deposition conditions.

  12. Hydroxyapatite formation on graphene oxide modified with amino acids: arginine versus glutamic acid

    PubMed Central

    Tavafoghi, M.; Brodusch, N.; Gauvin, R.; Cerruti, M.

    2016-01-01

    Hydroxyapatite (HA, Ca5(PO4)3OH) is the main inorganic component of hard tissues, such as bone and dentine. HA nucleation involves a set of negatively charged phosphorylated proteins known as non-collagenous proteins (NCPs). These proteins attract Ca2+ and PO43− ions and increase the local supersaturation to a level required for HA precipitation. Polar and charged amino acids (AAs) are highly expressed in NCPs, and seem to be responsible for the mineralizing effect of NCPs; however, the individual effect of these AAs on HA mineralization is still unclear. In this work, we investigate the effect of a negatively charged (Glu) and positively charged (Arg) AA bound to carboxylated graphene oxide (CGO) on HA mineralization in simulated body fluids (SBF). Our results show that Arg induces HA precipitation faster and in larger amounts than Glu. We attribute this to the higher stability of the complexes formed between Arg and Ca2+ and PO43− ions, and also to the fact that Arg exposes both carboxyl and amino groups on the surface. These can electrostatically attract both Ca2+ and PO43− ions, thus increasing local supersaturation more than Glu, which exposes carboxyl groups only. PMID:26791001

  13. Hydroxyapatite formation on graphene oxide modified with amino acids: arginine versus glutamic acid.

    PubMed

    Tavafoghi, M; Brodusch, N; Gauvin, R; Cerruti, M

    2016-01-01

    Hydroxyapatite (HA, Ca5(PO4)3OH) is the main inorganic component of hard tissues, such as bone and dentine. HA nucleation involves a set of negatively charged phosphorylated proteins known as non-collagenous proteins (NCPs). These proteins attract Ca(2+) and PO4(3-) ions and increase the local supersaturation to a level required for HA precipitation. Polar and charged amino acids (AAs) are highly expressed in NCPs, and seem to be responsible for the mineralizing effect of NCPs; however, the individual effect of these AAs on HA mineralization is still unclear. In this work, we investigate the effect of a negatively charged (Glu) and positively charged (Arg) AA bound to carboxylated graphene oxide (CGO) on HA mineralization in simulated body fluids (SBF). Our results show that Arg induces HA precipitation faster and in larger amounts than Glu. We attribute this to the higher stability of the complexes formed between Arg and Ca(2+) and PO4(3-) ions, and also to the fact that Arg exposes both carboxyl and amino groups on the surface. These can electrostatically attract both Ca(2+) and PO4(3-) ions, thus increasing local supersaturation more than Glu, which exposes carboxyl groups only. © 2016 The Author(s).

  14. Removal of fluoride from drinking water by cellulose@hydroxyapatite nanocomposites.

    PubMed

    Yu, Xiaolin; Tong, Shengrui; Ge, Maofa; Zuo, Junchao

    2013-01-30

    Cellulose@hydroxyapatite (HA) nanocomposites were prepared in NaOH/thiourea/urea/H(2)O solution via situ hybridization. The composite materials combine the advantage of cellulose and HA with the high specific surface area and the strong affinity toward fluoride. The composite materials were characterized by FTIR, SEM, XRD, TG and XPS, and the adsorption of fluoride was investigated. Adsorption kinetics indicated the adsorption equilibrium of fluoride was within 360 min and the adsorption process was well described by the pseudo-second-order kinetic model. The Langmuir and Freundlich isotherm models could fit the experimental data well. At the initial fluoride concentration of 10mg/L, the residual concentration using above 3g/L adsorbent dose could meet the drinking water standard of WHO norms. Furthermore, the coexisting anions had no significant effect on fluoride adsorption. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. [Characteristics of hydroxyapatite/PMMA nanocomposites for provisional restoration and its biocompatibility with human gingival fibroblasts].

    PubMed

    Zhang, Jing-chao; Mo, An-chun; Li, Ji-dong; Wang, Xue-jiang; Li, Yu-bao

    2014-05-01

    To formulate hydroxyapatite (HA)/polymethyl methacrylate (PMMA) composites with improved cytocompatibility for provisional restoration. Nanocomposites with 20 wt%, 30 wt%, 40 wt%, and 50 wt% HA/PMMA (H/P) were developed and examined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). Human gingival fibroblasts were cultured on those HA/PMMA discs and investigated by fluorescent staining on 24 h and MTT assay at 1 d, 3 d, 5 d and 7 d. Chemical integration of HA/PMMA interface was confirmed by XPS. Typical fusiform cells with adhesion spots were detected on 40 wt% and 50 wt% H/P discs. MTT results showed insignificant differences in cell growth between 40 wt% H/P and pure titanium (Ti, P > 0.05), while the other H/P discs showed significantly lower cell growth than pure Ti (P < 0.05). 40 wt% H/P might be a promising candidate for provisional dental implant restoration and for esthetic gingival contour.

  16. Direct cytotoxicity evaluation of 63S bioactive glass and bone-derived hydroxyapatite particles using yeast model and human chondrocyte cells by microcalorimetry.

    PubMed

    Doostmohammadi, A; Monshi, A; Fathi, M H; Karbasi, S; Braissant, O; Daniels, A U

    2011-10-01

    In this study, the cytotoxicity evaluation of prepared 63S bioactive glass and bone-derived hydroxyapatite particles with yeast and human chondrocyte cells was carried out using isothermal micro-nano calorimetry (IMNC), which is a new method for studying cell/biomaterial interactions. Bioactive glass particles were made via sol-gel method and hydroxyapatite was obtained from bovine bone. Elemental analysis was carried out by XRF and EDXRF. Amorphous structure of the glass and completely crystalline structure of HA were detected by XRD analysis. Finally, the cytotoxicity of bioactive glass and bone-derived HA particles with yeast and cultured human chondrocyte cells was evaluated using IMNC. The results confirmed the viability, growth and proliferation of human chondrocyte cells in contact with 63S bioactive glass, and bone-derived HA particles. Also the results indicated that yeast model which is much easier to handle, can be considered as a good proxy and can provide a rapid primary estimate of the ranges to be used in assays involving human cells. All of these results confirmed that IMNC is a convenient method which caters to measuring the cell-biomaterial interactions alongside the current methods.

  17. Studies on crosslinked hydroxyapatite-polyethylene composite as a bone-analogue material

    NASA Astrophysics Data System (ADS)

    Smolko, E.; Romero, G.

    2007-08-01

    The paper examines the use of different types of polymeric matrix composites in hard-tissue replacement applications. The composite samples were prepared with hydroxyapatite (HA) powder and polyethylenes of different densities. The raw material was first compounded in the extruder and the resulting composite pre-forms were compression molded into desired plates and irradiated with different doses. Modulus of elasticity in tension, tensile strength, tensile fracture strain, elongation at break and gel content were obtained for all composites. Ceramic filler distribution was investigated under scanning electron microscopy (SEM). With HA incorporated in the samples an increase in the values of Young's Modulus, (stiffness) was observed, while elongation at break decreased with the amount of filler, showing increase of brittleness. Tensile strengths at yield and at break decreased with the filler content for LD and MDPE and stayed constant for HDPE.

  18. Syntheses of near-net-shaped monolithic hydroxyapatite and hydroxyapatite-ASTM F75 composites by the oxidation of solid metal-bearing precursors

    NASA Astrophysics Data System (ADS)

    Saw, Eaden

    A novel powder-metallurgical route was used to fabricate near net-shaped hydroxyapatite, Ca10(PO4)6(OH)2 (HA) and HA+Co-C-Mo composite bodies. Ca and beta-Ca2P 2O7 with Ca/P ˜ 1.67 was intimately mixed by high-energy mechanical alloying, formed into desired shapes by pressing and machining, and then converted into HA with a series of heat treatments: a 600°C annealing in dry O2 completely oxidized calcium within 3 h, and a subsequent annealing at ≤1150°C in moist O2 yielded phase-pure HA. The reduction in solid volume associated with the oxidation of calcium (Vm[CaO] < Vm[Ca]) was offset by the increase in solid volume associated with the conversion of CaO and Ca2P2O7 into HA. Thus, the overall dimensional changes upon transformation of Ca+beta-Ca2P 2O7 precursors into HA can be relatively small. A mixture of Co-Cr-Mo powder with the precursor prepared from Ca and beta-Ca 2P2O7, targeted to yield a 75 to 25 volume ratio of Co-Cr-Mo to stoichiometric HA were prepared with the same method but different annealing cycles: annealing at 1150°C in de-oxygenized, flowing Ar resulted in partial densification of the composite bodies, and subsequent annealing at 850°C in a moist O2 atmosphere yielded a composite of Co-Cr-Mo alloy with phase-pure HA. The overall dimensional changes upon transformation of Ca+beta-Ca2P2O7+CO-Cr-Mo precursors into HA/Co-Cr-Mo composite were relatively small. In this thesis, the phase and microstructural evolution at various stages of transformation to monolithic HA and to HA/Co-Cr-Mo alloy composites are discussed. Planar reaction couples and powder compacts of CaO-TCP were prepared to study the kinetics for HA formation from CaO+TCP. Pt strips were used in the planar reaction couples as inert markers. These reaction couples were heated at 1150°C for various times in moist O2. The results of powder compact analyses fits Carter's model, which indicated that the rate of HA conversion from CaO and TCP is limited by solid state diffusion of

  19. In situ growth of hydroxyapatite within electrospun poly(DL-lactide) fibers.

    PubMed

    Cui, Wenguo; Li, Xiaohong; Zhou, Shaobing; Weng, Jie

    2007-09-15

    Development of nanocomposites of hydroxyapatite (HA) and polylactic acid (PLA) is attractive, as the advantageous properties of the two types of materials can be combined to suit better the mechanical and biological demands for biomedical uses. To solve the problematic issue of agglomeration of HA crystallites in the PLA matrix, a novel method is introduced in the present study to use electrospun nanofibers as the reaction confinement for composite fabrication. Poly(DL-lactide) ultrafine fibers with calcium nitrate entrapment were prepared by electrospinning and then incubated in phosphate solution to form in situ calcium phosphate on the polymer matrix. The formation of nonstoichiometric nanostructured HA and well dispersion of HA particles on the electrospun fibers were observed. Higher crystalline HA phase was indicated in samples after sintering at 1200 degrees C. The formation of the calcium-phosphate phase was dependent upon the precipitation conditions, and the effects of the incubation time, temperature, and the pH values of the incubation medium were investigated on the spontaneous precipitation and amorphous-crystalline transformation of HA in the current study. Considering the biodegradability of matrix polymer and the crystallinity and uniform dispersal of HA, optimal conditions for composite preparation were incubating calcium-containing ultrafine fibers at 37 degrees C in pH 7.4 or at 25 degrees C in pH 9.0 of diammonium hydrogen phosphate solutions for 7 days. Around 25%-34% of mineral contents can be synthesized in the resulting composites, which was higher than the theoretical value due to the nonstoichiometric HA formed in the composite, and the fiber degradation and partial calcium nitrate involved in the HA formation. Copyright 2007 Wiley Periodicals, Inc.

  20. Synthesis and Characterization of Hydroxyapatite/Fullerenol Nanocomposites.

    PubMed

    Djordjevic, Aleksandar; Ignjatovic, Nenad; Seke, Mariana; Jovic, Danica; Uskokovic, Dragan; Rakocevic, Zlatko

    2015-02-01

    Fullerenols are polyhydroxylated, water soluble derivatives of fullerene C60, with potential application in medicine as diagnostic agents, antioxidants or nano drug carriers. This paper describes synthesis and physical characterization of a new nanocomposite hydroxyapatite/fullerenol. Surface of the nanocomposite hydroxyapatite/fullerenol is inhomogeneous with the diameter of the particles in the range from 100 nm to 350 nm. The ζ potential of this nanocomposite is ten times lower when compared to hydroxyapatite. Surface phosphate groups of hydroxyapatite are prone to forming hydrogen bonds, when in close contact with hydroxyl groups, which could lead to formation of hydrogen bonds between hydroxyapatite and hydroxyl groups of fullerenol. The surface of hydroxyapatite particles (-2.5 mV) was modified by fullerenol particles, as confirmed by the obtained ζ potential value of the nanocomposite biomaterial hydroxyapatite/fullerenol (-25.0 mV). Keywords: Hydroxyapatite, Fullerenol, Nanocomposite, Surface Analysis.