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Sample records for composite microsphere scaffolds

  1. Multiscale patterning of a biomimetic scaffold integrated with composite microspheres.

    PubMed

    Minardi, Silvia; Sandri, Monica; Martinez, Jonathan O; Yazdi, Iman K; Liu, Xeuwu; Ferrari, Mauro; Weiner, Bradley K; Tampieri, Anna; Tasciotti, Ennio

    2014-10-15

    The ideal scaffold for regenerative medicine should concurrently mimic the structure of the original tissue from the nano- up to the macroscale and recapitulate the biochemical composition of the extracellular matrix (ECM) in space and time. In this study, a multiscale approach is followed to selectively integrate different types of nanostructured composite microspheres loaded with reporter proteins, in a multi-compartment collagen scaffold. Through the preservation of the structural cues of the functionalized collagen scaffold at the nano- and microscale, its macroscopic features (pore size, porosity, and swelling) are not altered. Additionally, the spatial confinement of the microspheres allows the release of the reporter proteins in each of the layers of the scaffold. Finally, the staged and zero-order release kinetics enables the temporal biochemical patterning of the scaffold. The versatile manufacturing of each component of the scaffold results in the ability to customize it to better mimic the architecture and composition of the tissues and biological systems. PMID:24867543

  2. Preparation and characterization of PHBV microsphere/45S5 bioactive glass composite scaffolds with vancomycin releasing function.

    PubMed

    Li, Wei; Ding, Yaping; Rai, Ranjana; Roether, Judith A; Schubert, Dirk W; Boccaccini, Aldo R

    2014-08-01

    PHBV microsphere/45S5 bioactive glass (BG) composite scaffolds with drug release function were developed for bone tissue engineering. BG-based glass-ceramic scaffolds with high porosity (94%) and interconnected pore structure prepared by foam replication method were coated with PHBV microspheres (nominal diameter=3.5 μm) produced by water-in-oil-in-water double emulsion solvent evaporation method. A homogeneous microsphere coating throughout the porous structure of scaffolds was obtained by a simple dip coating method, using the slurry of PHBV microspheres in hexane. Compressive strength tests showed that the microsphere coating slightly improved the mechanical properties of the scaffolds. It was confirmed that the microsphere coating did not inhibit the bioactivity of the scaffolds in SBF. Hydroxyapatite crystals homogeneously grew not only on the struts of the scaffolds but also on the surface of microspheres within 7 days of immersion in SBF. Vancomycin was successfully encapsulated into the PHBV microspheres. The encapsulated vancomycin was released with a dual release profile involving a relatively low initial burst release (21%) and a sustained release (1 month), which is favorable compared to the high initial burst release (77%) and short release period (4 days) measured on uncoated scaffolds. The developed bioactive composite scaffold with drug delivery function has thus the potential to be used advantageously in bone tissue engineering. PMID:24907766

  3. Composite microsphere-functionalized scaffold for the controlled release of small molecules in tissue engineering.

    PubMed

    Pandolfi, Laura; Minardi, Silvia; Taraballi, Francesca; Liu, Xeuwu; Ferrari, Mauro; Tasciotti, Ennio

    2016-01-01

    Current tissue engineering strategies focus on restoring damaged tissue architectures using biologically active scaffolds. The ideal scaffold would mimic the extracellular matrix of any tissue of interest, promoting cell proliferation and de novo extracellular matrix deposition. A plethora of techniques have been evaluated to engineer scaffolds for the controlled and targeted release of bioactive molecules to provide a functional structure for tissue growth and remodeling, as well as enhance recruitment and proliferation of autologous cells within the implant. Recently, novel approaches using small molecules, instead of growth factors, have been exploited to regulate tissue regeneration. The use of small synthetic molecules could be very advantageous because of their stability, tunability, and low cost. Herein, we propose a chitosan-gelatin scaffold functionalized with composite microspheres consisting of mesoporous silicon microparticles and poly(dl-lactic-co-glycolic acid) for the controlled release of sphingosine-1-phospate, a small molecule of interest. We characterized the platform with scanning electron microscopy, Fourier transform infrared spectroscopy, and confocal microscopy. Finally, the biocompatibility of this multiscale system was analyzed by culturing human mesenchymal stem cells onto the scaffold. The presented strategy establishes the basis of a versatile scaffold for the controlled release of small molecules and for culturing mesenchymal stem cells for regenerative medicine applications. PMID:26977286

  4. Composite microsphere-functionalized scaffold for the controlled release of small molecules in tissue engineering

    PubMed Central

    Pandolfi, Laura; Minardi, Silvia; Taraballi, Francesca; Liu, Xeuwu; Ferrari, Mauro; Tasciotti, Ennio

    2016-01-01

    Current tissue engineering strategies focus on restoring damaged tissue architectures using biologically active scaffolds. The ideal scaffold would mimic the extracellular matrix of any tissue of interest, promoting cell proliferation and de novo extracellular matrix deposition. A plethora of techniques have been evaluated to engineer scaffolds for the controlled and targeted release of bioactive molecules to provide a functional structure for tissue growth and remodeling, as well as enhance recruitment and proliferation of autologous cells within the implant. Recently, novel approaches using small molecules, instead of growth factors, have been exploited to regulate tissue regeneration. The use of small synthetic molecules could be very advantageous because of their stability, tunability, and low cost. Herein, we propose a chitosan–gelatin scaffold functionalized with composite microspheres consisting of mesoporous silicon microparticles and poly(dl-lactic-co-glycolic acid) for the controlled release of sphingosine-1-phospate, a small molecule of interest. We characterized the platform with scanning electron microscopy, Fourier transform infrared spectroscopy, and confocal microscopy. Finally, the biocompatibility of this multiscale system was analyzed by culturing human mesenchymal stem cells onto the scaffold. The presented strategy establishes the basis of a versatile scaffold for the controlled release of small molecules and for culturing mesenchymal stem cells for regenerative medicine applications. PMID:26977286

  5. Modified composite microspheres of hydroxyapatite and poly(lactide-co-glycolide) as an injectable scaffold

    NASA Astrophysics Data System (ADS)

    Hu, Xixue; Shen, Hong; Yang, Fei; Liang, Xinjie; Wang, Shenguo; Wu, Decheng

    2014-02-01

    The compound of hydroxyapatite-poly(lactide-co-glycolide) (HA-PLGA) was prepared by ionic bond between HA and PLGA. HA-PLGA was more stable than the simple physical blend of hydroxyapatite and poly(lactide-co-glycolide) (HA/PLGA). The surface of HA-PLGA microsphere fabricated by an emulsion-solvent evaporation method was rougher than that of HA/PLGA microspheres. Moreover, surface HA content of HA-PLGA microspheres was more than that of HA/PLGA microspheres. In vitro mouse OCT-1 osteoblast-like cell culture results showed that the HA-PLGA microspheres clearly promoted osteoblast attachment, proliferation and alkaline phosphatase activity. It was considered that surface rich HA component and rough surface of HA-PLGA microsphere enhanced cell growth and differentiation. The good cell affinity of the HA-PLGA microspheres indicated that they could be used as an injectable scaffold for bone tissue engineering.

  6. Biocompatibility and osteogenesis of calcium phosphate composite scaffolds containing simvastatin-loaded PLGA microspheres for bone tissue engineering.

    PubMed

    Zhang, Hao-Xuan; Xiao, Gui-Yong; Wang, Xia; Dong, Zhao-Gang; Ma, Zhi-Yong; Li, Lei; Li, Yu-Hua; Pan, Xin; Nie, Lin

    2015-10-01

    By utilizing a modified solid/oil/water (s/o/w) emulsion solvent evaporation technique, calcium phosphate composite scaffolds containing simvastatin-loaded PLGA microspheres (SIM-PLGA-CPC) were prepared in this study. We characterized the morphology, encapsulation efficiency and in vitro drug release of SIM-loaded PLGA microspheres as well as the macrostructure, pore size, porosity and mechanical strength of the scaffolds. Rabbit bone mesenchymal stem cells (BMSCs) were seeded onto SIM-PLGA-CPC scaffolds, and the proliferation, morphology, cell cycle and differentiation of BMSCs were investigated using the cell counting kit-8 (CCK-8) assay, scanning electron microscopy (SEM), flow cytometry, alkaline phosphatase (ALP) activity and alizarin red S staining, respectively. The results revealed that SIM-PLGA-CPC scaffolds were biocompatible and osteogenic in vitro. To determine the in vivo biocompatibility and osteogenesis of the scaffolds, both pure PLGA-CPC scaffolds and SIM-PLGA-CPC scaffolds were implanted in rabbit femoral condyles and microradiographically and histologically investigated. SIM-PLGA-CPC scaffolds exhibited good biocompatibility and could improve the efficiency of new bone formation. All these results suggested that the SIM-PLGA-CPC scaffolds fulfilled the basic requirements of bone tissue engineering scaffold and possessed application potentials in orthopedic surgery. PMID:25809455

  7. Sol-gel processed mupirocin silica microspheres loaded collagen scaffold: a synergistic bio-composite for wound healing.

    PubMed

    Perumal, Sathiamurthi; Ramadass, Satiesh kumar; Madhan, Balaraman

    2014-02-14

    Development of a bio-composite using synergistic combination is a promising strategy to address various pathological manifestations of acute and chronic wounds. In the present work, we have combined three materials viz., mupirocin as an antimicrobial drug, sol-gel processed silica microsphere as drug carrier for sustained delivery of drug and collagen, an established wound healer as scaffold. The mupirocin-loaded silica microspheres (Mu-SM) and Mu-SM loaded collagen scaffold were characterized for surface morphology, entrapment efficiency and distribution homogeneity, in vitro drug release, water uptake capacity, cell proliferation and antibacterial activity. In vivo wound healing efficacy of the bio-composite was experimented using full thickness excision wound model in Wistar albino rats. The Mu-SM incorporated collagen scaffold showed good in vitro characteristics in terms of better water uptake, sustained drug availability and antimicrobial activity. The wound closure analysis revealed that the complete epithelialisation was observed at 14.2 ± 0.44 days for Mu-SM loaded collagen, whereas this was 17.4 ± 0.44 days and 20.6 ± 0.54 days for collagen and control groups, respectively. Consequently, the synergistic strategy of combining mupirocin-loaded silica microspheres and collagen as a Mu-SM loaded collagen dressing material would be an ideal biomaterial for the treatment of surface wounds, burns and foot ulcers. PMID:24514452

  8. Pitch carbon microsphere composite

    NASA Technical Reports Server (NTRS)

    Price, H. L.; Nelson, J. B.

    1977-01-01

    Petroleum pitch carbon microspheres were prepared by flash heating emulsified pitch and carbonizing the resulting microspheres in an inert atmosphere. Microsphere composites were obtained from a mixture of microspheres and tetraester precursor pyrrone powder. Scanning electron micrographs of the composite showed that it was an aggregate of microspheres bonded together by the pyrrone at the sphere contact points, with voids in and among the microspheres. Physical, thermal, and sorption properties of the composite are described. Composite applications could include use as a honeycomb filler in elevated-temperature load-bearing sandwich boards or in patient-treatment tables for radiation treatment of tumors.

  9. Hydroxyapatite/polyurethane scaffold incorporated with drug-loaded ethyl cellulose microspheres for bone regeneration.

    PubMed

    Liu, Haohuai; Zhang, Li; Shi, Pujiang; Zou, Qin; Zuo, Yi; Li, Yubao

    2010-10-01

    The purpose of this study is to explore and develop biodegradable scaffold for bone regeneration or tissue engineering with the capacity of controlled drug delivery. Ceftazidime as a model drug was encapsulated in ethyl cellulose (EC) microspheres, which were subsequently incorporated in a hydroxyapatite/polyurethane (HA/PU) composite scaffold to generate an antibiotic drug delivery system. HA/PU scaffolds had an interconnected pore network with an average porosity of about 83%. The presence of microspheres in the composite scaffolds was confirmed by scanning electron microscopy. The drug-loaded EC microspheres were uniformly distributed in the HA/PU scaffold matrix and showed no significant effect on the pore structure of the scaffold. Incorporation of microspheres into scaffolds significantly reduced the initial burst release, and the system exhibited a sustained release of the model drug for up to 60 days. Moreover, the scaffold with drug-loaded microspheres was proved to be an effective drug delivery system with good cytocompatibility and antibacterial properties. The novel drug-loaded microsphere/scaffold composites developed in this study are promising to serve as vehicles for controlled drug delivery in bone regeneration or bone tissue engineering. PMID:20665683

  10. 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 6μm, a specific surface area of 40m(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 16nm. 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 200μm, 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 15days 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. PMID:27040244

  11. Effects of Nano-hydroxyapatite/Poly(DL-lactic-co-glycolic acid) Microsphere-Based Composite Scaffolds on Repair of Bone Defects: Evaluating the Role of Nano-hydroxyapatite Content.

    PubMed

    He, Shu; Lin, Kai-Feng; Sun, Zhen; Song, Yue; Zhao, Yi-Nan; Wang, Zheng; Bi, Long; Liu, Jian

    2016-07-01

    The aim of the current study was to prepare microsphere-based composite scaffolds made of nano-hydroxyapatite (nHA)/poly (DL-lactic-co-glycolic acid) (PLGA) at different ratios and evaluate the effects of nHA on the characteristics of scaffolds for tissue engineering application. First, microsphere-based composite scaffolds made of two ratios of nHA/PLGA (nHA/PLGA = 20/80 and nHA/PLGA = 50/50) were prepared. Then, the effects of nHA on the wettability, mechanical strength, and degradation of scaffolds were investigated. Second, the biocompatibility and osteoinductivity were evaluated and compared by co-culture of scaffolds with bone marrow stromal stem cells (BMSCs). The results showed that the adhesion, proliferation, and osteogenic differentiation of BMSCs with nHA/PLGA (50/50) were better than those with nHA/PLGA (20/80). Finally, we implanted the scaffolds into femur bone defects in a rabbit model, then the capacity of guiding bone regeneration as well as the in vivo degradation were observed by micro-CT and histological examinations. After 4 weeks' implantation, there was no significant difference on the repair of bone defects. However, after 8 and 12 weeks' implantation, the nHA/PLGA (20/80) exhibited better bone formation than nHA/PLGA (50/50). These results suggested that a proper concentration of nHA in the nHA/PLGA composite should be taken into account when the composite scaffolds were prepared, which plays an important role in the biocompatibility, degradation rate and osteoconductivity. PMID:27378617

  12. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    NASA Technical Reports Server (NTRS)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  13. Delivery of Bioactive Lipids from Composite Microgel-Microsphere Injectable Scaffolds Enhances Stem Cell Recruitment and Skeletal Repair

    PubMed Central

    Das, Anusuya; Barker, Daniel A.; Wang, Tiffany; Lau, Cheryl M.; Lin, Yong; Botchwey, Edward A.

    2014-01-01

    In this study, a microgel composed of chitosan and inorganic phosphates was used to deliver poly(lactic-co-glycolic acid) (PLAGA) microspheres loaded with sphingolipid growth factor FTY720 to critical size cranial defects in Sprague Dawley rats. We show that sustained release of FTY720 from injected microspheres used alone or in combination with recombinant human bone morphogenic protein-2 (rhBMP2) improves defect vascularization and bone formation in the presence and absence of rhBMP2 as evaluated by quantitative microCT and histological measurements. Moreover, sustained delivery of FTY720 from PLAGA and local targeting of sphingosine 1-phosphate (S1P) receptors reduces CD45+ inflammatory cell infiltration, promotes endogenous recruitment of CD29+CD90+ bone progenitor cells and enhances the efficacy of rhBMP2 from chitosan microgels. Companion in vitro studies suggest that selective activation of sphingosine receptor subtype-3 (S1P3) via FTY720 treatment induces smad-1 phosphorylation in bone-marrow stromal cells. Additionally, FTY720 enhances stromal cell-derived factor-1 (SDF-1) mediated chemotaxis of CD90+CD11B-CD45- bone progenitor cells in vitro after stimulation with rhBMP2. We believe that use of such small molecule delivery formulations to recruit endogenous bone progenitors may be an attractive alternative to exogenous cell-based therapy. PMID:25077607

  14. Modification and cytocompatibility of biocomposited porous PLLA/HA-microspheres scaffolds.

    PubMed

    Xiao, Guiyong; Yin, Han; Xu, Wenhua; Lu, Yupeng

    2016-10-01

    Poly(L-lactic acid) and hydroxyapatie (PLLA/HA) composite scaffolds have good properties and suit to use as bone tissue engineering. In this work, hollow HA microspheres (HAM) with poor crystallinity were fabricated by a flame-drying method. The HAM has the potential to be used to release drugs or proteins in addition to improve osteoconductivity. Different ratios of PLLA/HAM were used to prepare porous composite scaffolds using the thermally induced phase separation technique. The HAMs were randomly incorporated into the PLLA porous scaffolds. As the HAMs ratio was increased, the porous composite scaffolds changed from ladder-like into isotropic structure. In addition, the compressive strength of PLLA/HAMs composite scaffolds improved first and declined with the increasing of HAMs ratio in the scaffolds. In vitro experiment showed that PLLA/HAMs composite scaffolds improved the attachment, migration, and differentiation of osteoblastic cells. These results demonstrated that the PLLA/HAMs composite scaffolds were superior to plain PLLA scaffold for bone tissue engineering. PMID:27398630

  15. RhBMP-2 microspheres-loaded chitosan/collagen scaffold enhanced osseointegration: an experiment in dog.

    PubMed

    Shi, Shanshan; Cheng, Xiangrong; Wang, Jiawei; Zhang, Wei; Peng, Lin; Zhang, Yufeng

    2009-01-01

    The purpose of this study is to develop a novel recombinant human bone morphogenetic protein-2 (rhBMP-2) sustained release scaffold for dental implant osseointegration, and to evaluate the effect of this scaffold on promoting bone formation. RhBMP-2 was encapsulated in the poly-D,L-lactide-co-glycolide (PLGA) biodegradable microspheres, which were subsequently dispersed in a chitosan/collagen composite scaffold. This rhBMP-2 microspheres-loaded scaffold (S-MB) was compared with a chitosan/collagen scaffold without microspheres that directly encapsulated rhBMP-2 (S-B) in vitro and in vivo. The microstructure of the new scaffold was examined with scanning electron microscopy. The release profile of rhBMP-2 in vitro was measured at interval periods. The effect of rhBMP-2 encapsulated scaffolds on enhancing bone formation through implantation in dogs' mandibles was identified by histological examination of the regenerated bone after 4 weeks of implantation. Due to PLGA microspheres being loaded, the S-MB exhibited lower values at porosity and swelling rate, as well as a higher effective release dose than that of the S-B. Bone density, bone-implant contact, and bone-fill values measured from dog experiments demonstrated that the S-MB induced bone regeneration more quickly and was timely substituted by new bone. It was concluded that this sustained carrier scaffold based on microspheres was more effective to induce implant osseointegration. PMID:18667455

  16. Bioactive Microsphere-Based Scaffolds Containing Decellularized Cartilage.

    PubMed

    Sutherland, Amanda J; Detamore, Michael S

    2015-07-01

    The aim of this study was to fabricate mechanically functional microsphere-based scaffolds containing decellularized cartilage (DCC), with the hypothesis that this approach would induce chondrogenesis of rat bone marrow-derived mesenchymal stem cells (rBMSCs) in vitro. The DCC was derived from porcine articular cartilage and decellularized using a combination of physical and chemical methods. Four types of scaffolds were fabricated: poly(d,l-lactic-co-glycolic acid) (PLGA) only (negative control), TGF-β-encapsulated (positive control), PLGA surface coated with DCC, and DCC-encapsulated. These scaffolds were seeded with rBMSCs and cultured up to 6 weeks. The compressive modulus of the DCC-coated scaffolds prior to cell seeding was significantly lower than all other scaffold types. Gene expression was comparable between DCC-encapsulated and TGF-β-encapsulated groups. Notably, DCC-encapsulated scaffolds contained 70% higher glycosaminoglyan (GAG) content and 85% more hydroxyproline compared to the TGF-β group at week 3 (with baseline levels subtracted out from acellular DCC scaffolds). Certainly, bioactivity was demonstrated in eliciting a biosynthetic response from the cells with DCC, although true demonstration of chondrogenesis remained elusive under the prescribed conditions. Encapsulation of DCC appeared to lead to improved cell performance relative to coating with DCC, although this finding may be a dose-dependent observation. Overall, DCC introduced via microsphere-based scaffolds appears to be promising as a bioactive approach to cartilage regeneration, although additional studies will be required to conclusively demonstrate chondroinductivity. PMID:25821206

  17. Microsphere-based scaffolds encapsulating chondroitin sulfate or decellularized cartilage.

    PubMed

    Gupta, Vineet; Tenny, Kevin M; Barragan, Marilyn; Berkland, Cory J; Detamore, Michael S

    2016-09-01

    Extracellular matrix materials such as decellularized cartilage (DCC) and chondroitin sulfate (CS) may be attractive chondrogenic materials for cartilage regeneration. The goal of the current study was to investigate the effects of encapsulation of DCC and CS in homogeneous microsphere-based scaffolds, and to test the hypothesis that encapsulation of these extracellular matrix materials would induce chondrogenesis of rat bone marrow stromal cells. Four different types of homogeneous scaffolds were fabricated from microspheres of poly(D,L-lactic-co-glycolic acid): Blank (poly(D,L-lactic-co-glycolic acid) only; negative control), transforming growth factor-β3 encapsulated (positive control), DCC encapsulated, and CS encapsulated. These scaffolds were then seeded with rat bone marrow stromal cells and cultured for 6 weeks. The DCC and CS encapsulation altered the morphological features of the microspheres, resulting in higher porosities in these groups. Moreover, the mechanical properties of the scaffolds were impacted due to differences in the degree of sintering, with the CS group exhibiting the highest compressive modulus. Biochemical evidence suggested a mitogenic effect of DCC and CS encapsulation on rat bone marrow stromal cells with the matrix synthesis boosted primarily by the inherently present extracellular matrix components. An important finding was that the cell seeded CS and DCC groups at week 6 had up to an order of magnitude higher glycosaminoglycan contents than their acellular counterparts. Gene expression results indicated a suppressive effect of DCC and CS encapsulation on rat bone marrow stromal cell chondrogenesis with differences in gene expression patterns existing between the DCC and CS groups. Overall, DCC and CS were easily included in microsphere-based scaffolds; however, there is a requirement to further refine their concentrations to achieve the differentiation profiles we seek in vitro. PMID:27358376

  18. Electrospinning Growth Factor Releasing Microspheres into Fibrous Scaffolds

    PubMed Central

    Whitehead, Tonya J.; Sundararaghavan, Harini G.

    2014-01-01

    This procedure describes a method to fabricate a multifaceted substrate to direct nerve cell growth. This system incorporates mechanical, topographical, adhesive and chemical signals. Mechanical properties are controlled by the type of material used to fabricate the electrospun fibers. In this protocol we use 30% methacrylated Hyaluronic Acid (HA), which has a tensile modulus of ~500 Pa, to produce a soft fibrous scaffold. Electrospinning on to a rotating mandrel produces aligned fibers to create a topographical cue. Adhesion is achieved by coating the scaffold with fibronectin. The primary challenge addressed herein is providing a chemical signal throughout the depth of the scaffold for extended periods. This procedure describes fabricating poly(lactic-co-glycolic acid) (PLGA) microspheres that contain Nerve Growth Factor (NGF) and directly impregnating the scaffold with these microspheres during the electrospinning process. Due to the harsh production environment, including high sheer forces and electrical charges, protein viability is measured after production. The system provides protein release for over 60 days and has been shown to promote primary nerve cell growth. PMID:25178038

  19. Microsphere-Based Scaffolds Carrying Opposing Gradients of Chondroitin Sulfate and Tricalcium Phosphate

    PubMed Central

    Gupta, Vineet; Mohan, Neethu; Berkland, Cory J.; Detamore, Michael S.

    2015-01-01

    Extracellular matrix (ECM) components, such as chondroitin sulfate (CS) and tricalcium phosphate, serve as raw materials, and thus spatial patterning of these raw materials may be leveraged to mimic the smooth transition of physical, chemical, and mechanical properties at the bone-cartilage interface. We hypothesized that encapsulation of opposing gradients of these raw materials in high molecular weight poly(d,l-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds would enhance differentiation of rat bone marrow–derived stromal cells. The raw material encapsulation altered the microstructure of the microspheres and also influenced the cellular morphology that depended on the type of material encapsulated. Moreover, the mechanical properties of the raw material encapsulating microsphere-based scaffolds initially relied on the composition of the scaffolds and later on were primarily governed by the degradation of the polymer phase and newly synthesized ECM by the seeded cells. Furthermore, raw materials had a mitogenic effect on the seeded cells and led to increased glycosaminoglycan (GAG), collagen, and calcium content. Interestingly, the initial effects of raw material encapsulation on a per-cell basis might have been overshadowed by medium-regulated environment that appeared to favor osteogenesis. However, it is to be noted that in vivo, differentiation of the cells would be governed by the surrounding native environment. Thus, the results of this study demonstrated the potential of the raw materials in facilitating neo-tissue synthesis in microsphere-based scaffolds and perhaps in combination with bioactive signals, these raw materials may be able to achieve intricate cell differentiation profiles required for regenerating the osteochondral interface. PMID:26191526

  20. A study on the in vitro degradation of poly( l-lactide)/chitosan microspheres scaffolds

    NASA Astrophysics Data System (ADS)

    Zhu, Ning; Cooper, David; Chen, Xiong-Biao; Niu, Catherine Hui

    2013-03-01

    Recent research shows that the addition of chitosan microspheres (CMs) to poly( l-lactide) (PLLA) can result in a composite scaffold material with improved biocompatibility and mechanical properties for tissue engineering applications. However, research regarding the influence of CMs on scaffold degradation is absent in the literature. This paper presents a study on the in vitro degradation of scaffolds made from PLLA with CMs. In this study, the PLLA/CMs scaffolds with a 25% ratio of CMs to PLLA were immersed in phosphate-buffered saline (PBS) solution at 37°C for 8 weeks. The in vitro degradation of the scaffolds was investigated using microcomputed tomography (μCT), weight loss analysis, Raman spectroscopy, and differential scanning calorimetry (DSC). Microstructure changes during degradation were monitored using μCT. The μCT results were consistent with the results obtained from Raman spectra and DSC analysis, which reflected that adding CMs into PLLA can decrease the degradation rate compared with pure PLLA scaffolds. The results suggest that PLLA/CMs scaffold degradation can be regulated and controlled to meet requirements imposed a given tissue engineering application.

  1. Surface studies of coated polymer microspheres and protein release from tissue-engineered scaffolds.

    PubMed

    Meese, Thomas M; Hu, Yunhua; Nowak, Richard W; Marra, Kacey G

    2002-01-01

    The controlled release of growth factors from porous, polymer scaffolds is being studied for potential use as tissue-engineered scaffolds. Biodegradable polymer microspheres were coated with a biocompatible polymer membrane to permit the incorporation of the microspheres into tissue-engineered scaffolds. Surface studies with poly(D,L-lactic-co-glycolic acid) [PLGA], and poly(vinyl alcohol) [PVA] were conducted. Polymer films were dip-coated onto glass slides and water contact angles were measured. The contact angles revealed an initially hydrophobic PLGA film, which became hydrophilic after PVA coating. After immersion in water, the PVA coating was removed and a hydrophobic PLGA film remained. Following optimization using these 2D contact angle studies, biodegradable PLGA microspheres were prepared, characterized, and coated with PVA. X-ray photoelectron spectroscopy was used to further characterize coated slides and microspheres. The release of the model protein bovine serum albumin from PVA-coated PLGA microspheres was studied over 8 days. The release of BSA from PVA-coated PLGA microspheres embedded in porous PLGA scaffolds over 24 days was also examined. Coating of the PLGA microspheres with PVA permitted their incorporation into tissue-engineered scaffolds and resulted in a controlled release of BSA. PMID:12022746

  2. Microsphere-based selective laser sintering for building macroporous bone scaffolds with controlled microstructure and excellent biocompatibility.

    PubMed

    Du, Yingying; Liu, Haoming; Shuang, Jiaqi; Wang, Jianglin; Ma, Jun; Zhang, Shengmin

    2015-11-01

    Fabrication of bulk biomaterials with controlled structures and excellent properties is increasingly important in tissue engineering, but remains a major challenge in the current stage. Herein we used selective laser sintering (SLS) to construct a series of three-dimensional (3D) bone scaffolds with uniform multi-scaled porosity, moderate mechanical properties as well as good biocompatibility. As starting architectural units for SLS, the pure microspheres of polycaprolactone (PCL) and the composite microspheres of PCL and hydroxyapatite (HA) were firstly synthesized via a modified solvent evaporation method, respectively. Our findings showed that the as-prepared microspheres exhibited the uniform size and monodispersity. Moreover, the microsphere-based 3D scaffolds generated by SLS technique showed a multi-scaled porous structure, and adequate mechanical features. Both in vitro and in vivo evaluations further demonstrated that the resultant SLS-derived scaffolds can not only manipulate multiple stem cell behaviors including promoting cell adhesion, supporting cell proliferation and inducing cell differentiation in vitro, but also showed an excellent histocompatibility and induced the vascularization of newly formed tissue in vivo. Consequently, our current study suggests a feasible and effective protocol for fabricating new biomimetic bone biomaterials via SLS technique, also paves a new way for other bulk biomaterials. PMID:26241919

  3. Gelatin/chitosan/hyaluronan scaffold integrated with PLGA microspheres for cartilage tissue engineering.

    PubMed

    Tan, Huaping; Wu, Jindan; Lao, Lihong; Gao, Changyou

    2009-01-01

    Poly(lactide-co-glycotide) (PLGA) microspheres integrated into gelatin/chitosan/hyaluronan scaffolds were fabricated by freeze-drying and crosslinking with 1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide. The effects of the microspheres on porosity, density, compressive modulus, phosphate-buffered saline uptake ratio and weight loss of the scaffolds were evaluated. Generally, a scaffold with a higher PLGA content had a lower porosity and weight loss, and a medium uptake ratio, but a larger apparent density and compressive modulus. When the PLGA content was lower than 50%, the PLGA-integrated scaffolds had a similar pore size (approximately 200microm) as that of the control, and as much as 90% of their porosity could be preserved. In vitro chondrocyte culture in the 50% PLGA-integrated scaffold demonstrated that the cells could proliferate and secrete extracellular matrix at the same level as in the control gelatin/chitosan/hyaluronan scaffold. PMID:18723417

  4. Fabrication and evaluation of a sustained-release chitosan-based scaffold embedded with PLGA microspheres.

    PubMed

    Song, Kedong; Liu, Yingchao; Macedo, Hugo M; Jiang, Lili; Li, Chao; Mei, Guanyu; Liu, Tianqing

    2013-04-01

    Nutrient depletion within three-dimensional (3D) scaffolds is one of the major hurdles in the use of this technology to grow cells for applications in tissue engineering. In order to help in addressing it, we herein propose to use the controlled release of encapsulated nutrients within polymer microspheres into chitosan-based 3D scaffolds, wherein the microspheres are embedded. This method has allowed maintaining a stable concentration of nutrients within the scaffolds over the long term. The polymer microspheres were prepared using multiple emulsions (w/o/w), in which bovine serum albumin (BSA) and poly (lactic-co-glycolic) acid (PLGA) were regarded as the protein pattern and the exoperidium material, respectively. These were then mixed with a chitosan solution in order to form the scaffolds by cryo-desiccation. The release of BSA, entrapped within the embedded microspheres, was monitored with time using a BCA kit. The morphology and structure of the PLGA microspheres containing BSA before and after embedding within the scaffold were observed under a scanning electron microscope (SEM). These had a round shape with diameters in the range of 27-55 μm, whereas the chitosan-based scaffolds had a uniform porous structure with the microspheres uniformly dispersed within their 3D structure and without any morphological change. In addition, the porosity, water absorption and degradation rate at 37 °C in an aqueous environment of 1% chitosan-based scaffolds were (92.99±2.51) %, (89.66±0.66) % and (73.77±3.21) %, respectively. The studies of BSA release from the embedded microspheres have shown a sustained and cumulative tendency with little initial burst, with (20.24±0.83) % of the initial amount released after 168 h (an average rate of 0.12%/h). The protein concentration within the chitosan-based scaffolds after 168 h was found to be (11.44±1.81)×10(-2) mg/mL. This novel chitosan-based scaffold embedded with PLGA microspheres has proven to be a promising technique

  5. Cold Atmospheric Plasma Modified Electrospun Scaffolds with Embedded Microspheres for Improved Cartilage Regeneration.

    PubMed

    Zhu, Wei; Castro, Nathan J; Cheng, Xiaoqian; Keidar, Michael; Zhang, Lijie Grace

    2015-01-01

    Articular cartilage is prone to degeneration and possesses extremely poor self-healing capacity due to inherent low cell density and the absence of a vasculature network. Tissue engineered cartilage scaffolds show promise for cartilage repair. However, there still remains a lack of ideal biomimetic tissue scaffolds which effectively stimulate cartilage regeneration with appropriate functional properties. Therefore, the objective of this study is to develop a novel biomimetic and bioactive electrospun cartilage substitute by integrating cold atmospheric plasma (CAP) treatment with sustained growth factor delivery microspheres. Specifically, CAP was applied to a poly(ε-caprolactone) electrospun scaffold with homogeneously distributed bioactive factors (transforming growth factor-β1 and bovine serum albumin) loaded poly(lactic-co-glycolic) acid microspheres. We have shown that CAP treatment renders electrospun scaffolds more hydrophilic thus facilitating vitronectin adsorption. More importantly, our results demonstrate, for the first time, CAP and microspheres can synergistically enhance stem cell growth as well as improve chondrogenic differentiation of human marrow-derived mesenchymal stem cells (such as increased glycosaminoglycan, type II collagen, and total collagen production). Furthermore, CAP can substantially enhance 3D cell infiltration (over two-fold increase in infiltration depth after 1 day of culture) in the scaffolds. By integrating CAP, sustained bioactive factor loaded microspheres, and electrospinning, we have fabricated a promising bioactive scaffold for cartilage regeneration. PMID:26222527

  6. Cold Atmospheric Plasma Modified Electrospun Scaffolds with Embedded Microspheres for Improved Cartilage Regeneration

    PubMed Central

    Zhu, Wei; Castro, Nathan J.; Cheng, Xiaoqian; Keidar, Michael; Zhang, Lijie Grace

    2015-01-01

    Articular cartilage is prone to degeneration and possesses extremely poor self-healing capacity due to inherent low cell density and the absence of a vasculature network. Tissue engineered cartilage scaffolds show promise for cartilage repair. However, there still remains a lack of ideal biomimetic tissue scaffolds which effectively stimulate cartilage regeneration with appropriate functional properties. Therefore, the objective of this study is to develop a novel biomimetic and bioactive electrospun cartilage substitute by integrating cold atmospheric plasma (CAP) treatment with sustained growth factor delivery microspheres. Specifically, CAP was applied to a poly(ε-caprolactone) electrospun scaffold with homogeneously distributed bioactive factors (transforming growth factor-β1 and bovine serum albumin) loaded poly(lactic-co-glycolic) acid microspheres. We have shown that CAP treatment renders electrospun scaffolds more hydrophilic thus facilitating vitronectin adsorption. More importantly, our results demonstrate, for the first time, CAP and microspheres can synergistically enhance stem cell growth as well as improve chondrogenic differentiation of human marrow-derived mesenchymal stem cells (such as increased glycosaminoglycan, type II collagen, and total collagen production). Furthermore, CAP can substantially enhance 3D cell infiltration (over two-fold increase in infiltration depth after 1 day of culture) in the scaffolds. By integrating CAP, sustained bioactive factor loaded microspheres, and electrospinning, we have fabricated a promising bioactive scaffold for cartilage regeneration. PMID:26222527

  7. Injectable and porous PLGA microspheres that form highly porous scaffolds at body temperature.

    PubMed

    Qutachi, Omar; Vetsch, Jolanda R; Gill, Daniel; Cox, Helen; Scurr, David J; Hofmann, Sandra; Müller, Ralph; Quirk, Robin A; Shakesheff, Kevin M; Rahman, Cheryl V

    2014-12-01

    Injectable scaffolds are of interest in the field of regenerative medicine because of their minimally invasive mode of delivery. For tissue repair applications, it is essential that such scaffolds have the mechanical properties, porosity and pore diameter to support the formation of new tissue. In the current study, porous poly(dl-lactic acid-co-glycolic acid) (PLGA) microspheres were fabricated with an average size of 84±24μm for use as injectable cell carriers. Treatment with ethanolic sodium hydroxide for 2min was observed to increase surface porosity without causing the microsphere structure to disintegrate. This surface treatment also enabled the microspheres to fuse together at 37°C to form scaffold structures. The average compressive strength of the scaffolds after 24h at 37°C was 0.9±0.1MPa, and the average Young's modulus was 9.4±1.2MPa. Scaffold porosity levels were 81.6% on average, with a mean pore diameter of 54±38μm. This study demonstrates a method for fabricating porous PLGA microspheres that form solid porous scaffolds at body temperature, creating an injectable system capable of supporting NIH-3T3 cell attachment and proliferation in vitro. PMID:25152354

  8. Injectable and porous PLGA microspheres that form highly porous scaffolds at body temperature

    PubMed Central

    Qutachi, Omar; Vetsch, Jolanda R.; Gill, Daniel; Cox, Helen; Scurr, David J.; Hofmann, Sandra; Müller, Ralph; Quirk, Robin A.; Shakesheff, Kevin M.; Rahman, Cheryl V.

    2014-01-01

    Injectable scaffolds are of interest in the field of regenerative medicine because of their minimally invasive mode of delivery. For tissue repair applications, it is essential that such scaffolds have the mechanical properties, porosity and pore diameter to support the formation of new tissue. In the current study, porous poly(dl-lactic acid-co-glycolic acid) (PLGA) microspheres were fabricated with an average size of 84 ± 24 μm for use as injectable cell carriers. Treatment with ethanolic sodium hydroxide for 2 min was observed to increase surface porosity without causing the microsphere structure to disintegrate. This surface treatment also enabled the microspheres to fuse together at 37 °C to form scaffold structures. The average compressive strength of the scaffolds after 24 h at 37 °C was 0.9 ± 0.1 MPa, and the average Young’s modulus was 9.4 ± 1.2 MPa. Scaffold porosity levels were 81.6% on average, with a mean pore diameter of 54 ± 38 μm. This study demonstrates a method for fabricating porous PLGA microspheres that form solid porous scaffolds at body temperature, creating an injectable system capable of supporting NIH-3T3 cell attachment and proliferation in vitro. PMID:25152354

  9. Material characterization of microsphere-based scaffolds with encapsulated raw materials.

    PubMed

    Sridharan, BanuPriya; Mohan, Neethu; Berkland, Cory J; Detamore, Michael S

    2016-06-01

    "Raw materials," or materials capable of serving both as building blocks and as signals, which are often but not always natural materials, are taking center stage in biomaterials for contemporary regenerative medicine. In osteochondral tissue engineering, a field leveraging the underlying bone to facilitate cartilage regeneration, common raw materials include chondroitin sulfate (CS) for cartilage and β-tricalcium phosphate (TCP) for bone. Building on our previous work with gradient scaffolds based on microspheres, here we delved deeper into the characterization of individual components. In the current study, the release of CS and TCP from poly(d,l-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds was evaluated over a time period of 4weeks. Raw material encapsulated groups were compared to 'blank' groups and evaluated for surface topology, molecular weight, and mechanical performance as a function of time. The CS group may have led to increased surface porosity, and the addition of CS improved the mechanical performance of the scaffold. The finding that CS was completely released into the surrounding media by 4weeks has a significant impact on future in vivo studies, given rapid bioavailability. The addition of TCP seemed to contribute to the rough external appearance of the scaffold. The current study provides an introduction to degradation patterns of homogenous raw material encapsulated scaffolds, providing characterization data to advance the field of microsphere-based scaffolds in tissue engineering. PMID:27040236

  10. Microsphere-based scaffolds encapsulating tricalcium phosphate and hydroxyapatite for bone regeneration.

    PubMed

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

    2016-07-01

    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 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

  11. Preparation of porous microsphere-scaffolds by electrohydrodynamic forming and thermally induced phase separation.

    PubMed

    Ghanbar, Hanif; Luo, C J; Bakhshi, Poonam; Day, Richard; Edirisinghe, Mohan

    2013-07-01

    The availability of forming technologies able to mass produce porous polymeric microspheres with diameters ranging from 150 to 300 μm is significant for some biomedical applications where tissue augmentation is required. Moreover, appropriate assembly of microspheres into scaffolds is an important challenge to enable direct usage of the as-formed structures in treatments. This work reports the production of poly (glycolic-co-lactic acid) and poly (ε-caprolactone) microspheres under ambient conditions using one-step electrohydrodynamic jetting (traditionally known as atomisation) and thermally induced phase separation (TIPS). To ensure robust production for practical uses, this work presents 12 comprehensive parametric mode mappings of the diameter distribution profiles of the microspheres obtained over a broad range of key processing parameters and correlating of this with the material parameters of 5 different polymer solutions of various concentrations. Poly (glycolic-co-lactic acid) (PLGA) in Dimethyl carbonate (DMC), a low toxicity solvent with moderate conductivity and low dielectric constant, generated microspheres within the targeted diameter range of 150-300 μm. The fabrication of the microspheres suitable for formation of the scaffold structure is achieved by changing the collection method from distilled water to liquid nitrogen and lyophilisation in a freeze dryer. PMID:23623059

  12. PLGA/alginate composite microspheres for hydrophilic protein delivery.

    PubMed

    Zhai, Peng; Chen, X B; Schreyer, David J

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. PMID:26249587

  13. Preparation and characterization of gelatin-hydroxyapatite composite microspheres for hard tissue repair.

    PubMed

    Chao, Shao Ching; Wang, Ming-Jia; Pai, Nai-Su; Yen, Shiow-Kang

    2015-12-01

    Gelatin-hydroxyapatite composite microspheres composed of 21% gelatin (G) and 79% hydroxyapatite (HA) with uniform morphology and controllable size were synthesized from a mixed solution of Ca(NO3)2, NH4H2PO4 and gelatin by a wet-chemical method. Material analyses such as X-ray diffraction (XRD), scanning/transmission electron microscopy examination (SEM/TEM) and inductively coupled plasma-mass spectroscopy (ICP-MS) were used to characterize G-HA microspheres by analyzing their crystalline phase, microstructure, morphology and composition. HA crystals precipitate along G fibers to form nano-rods with diameters of 6-10nm and tangle into porous microspheres after blending. The cell culture indicates that G-HA composite microspheres without any toxicity could enhance the proliferation and differentiation of osteoblast-like cells. In a rat calvarial defect model, G-HA bioactive scaffolds were compared with fibrin glue (F) and Osteoset® Bone Graft Substitute (OS) for their capacity of regenerating bone. Four weeks post-implantation, new bone, mineralization, and expanded blood vessel area were found in G-HA scaffolds, indicating greater osteoconductivity and bioactivity than F and OS. PMID:26354246

  14. Seeing is believing, PLGA microsphere degradation revealed in PLGA microsphere/PVA hydrogel composites.

    PubMed

    Gu, Bing; Sun, Xuanhao; Papadimitrakopoulos, Fotios; Burgess, Diane J

    2016-04-28

    The aim of this study was to understand the polymer degradation and drug release mechanism from PLGA microspheres embedded in a PVA hydrogel. Two types of microspheres were prepared with different molecular weight PLGA polymers (approximately 25 and 7kDa) to achieve different drug release profiles, with a 9-day lag phase and without a lag phase, respectively. The kinetics of water uptake into the microspheres coincided with the drug release profiles for both formulations. For the 25kDa microspheres, minimal water uptake was observed in the early part of the lag phase followed by substantial water uptake at the later stages and in the drug release phase. For the 7kDa microspheres, water uptake occurred simultaneously with drug release. Water uptake was approximately 2-3 times that of the initial microsphere weight for both formulations. The internal structure of the PLGA microspheres was evaluated using low temperature scanning electron microscopy (cryo-SEM). Burst drug release occurred followed by pore forming from the exterior to the core of both microspheres. A well-defined hydrogel/microsphere interface was observed. For the 25kDa microspheres, internal pore formation and swelling occurred before the second drug release phase. The surface layer of the microspheres remained intact whereas swelling, and degradation of the core continued throughout the drug release period. In addition, microsphere swelling reduced glucose transport through the coatings in PBS media and this was considered to be a as a consequence of the increased thickness of the coatings. The combination of the swelling and microdialysis results provides a fresh understanding on the competing processes affecting molecular transport of bioanalytes (i.e. glucose) through these composite coatings during prolonged exposure in PBS. PMID:26965956

  15. Preparation and Functional Assessment of Composite Chitosan-Nano-Hydroxyapatite Scaffolds for Bone Regeneration

    PubMed Central

    Reves, Benjamin T.; Jennings, Jessica A.; Bumgardner, Joel D.; Haggard, Warren O.

    2012-01-01

    Composite chitosan-nano-hydroxyapatite microspheres and scaffolds prepared using a co-precipitation method have shown potential for use in bone regeneration. The goal of this research was to improve the functional properties of the composite scaffolds by modifying the fabrication parameters. The effects of degree of deacetylation (DDA), drying method, hydroxyapatite content and an acid wash on scaffold properties were investigated. Freeze-dried 61% DDA scaffolds degraded faster (3.5 ± 0.5% mass loss) than air-dried 61% DDA scaffolds and 80% DDA scaffolds, but had a lower compressive modulus of 0.12 ± 0.01 MPa. Air-dried 80% DDA scaffolds displayed the highest compressive modulus (3.79 ± 0.51 MPa) and these scaffolds were chosen as the best candidate for use in bone regeneration. Increasing the amount of hydroxyapatite in the air-dried 80% DDA scaffolds did not further increase the compressive modulus of the scaffolds. An acid wash procedure at pH 6.1 was found to increase the degradation of air-dried 80% DDA scaffolds from 1.3 ± 0.1% to 4.4 ± 0.4%. All of the formulations tested supported the proliferation of SAOS-2 cells. PMID:24956519

  16. TiO2 Sub-microsphere Film as Scaffold Layer for Efficient Perovskite Solar Cells.

    PubMed

    Huang, Yang; Zhu, Jun; Ding, Yong; Chen, Shuanghong; Zhang, Changneng; Dai, Songyuan

    2016-03-01

    TiO2 sub-microspheres composed of anatase granular-like nanocrystallines with an average diameter ∼250 nm are synthesized using sol-gel method and employed as the scaffold layer for efficient mesocopic perovskite solar cells. Compared with mesoporous TiO2 films composed of ∼18 nm nanoparticles, the sub-microsphere films show superior light-trapping characteristics and significantly improve the light-harvesting capability of the solar cells. In addition, the charge-transport performance is also dramatically improved according to the transient photocurrent decay despite there being no significant difference in the perovskite layer surface morphology. As a result, an average power conversion efficiency of 15% with a highly uniform distribution is achieved for the solar cells with TiO2 sub-microsphere films, 12% higher than those with TiO2 nanoparticle films. The combination of light-harvesting capability and fast charge transfer make the TiO2 sub-microsphere film a good candidate as the scaffold layer for efficient perovskite solar cells. PMID:26953635

  17. Tissue Engineering: Biomimetic Concealing of PLGA Microspheres in a 3D Scaffold to Prevent Macrophage Uptake (Small 11/2016).

    PubMed

    Minardi, Silvia; Corradetti, Bruna; Taraballi, Francesca; Sandri, Monica; Martinez, Jonathan O; Powell, Sebastian T; Tampieri, Anna; Weiner, Bradley K; Tasciotti, Ennio

    2016-03-01

    Avoiding the clearance of drug delivery systems from 3D scaffolds is crucial to preserve the bioactivity of their therapeutic payload. This is accomplished on page 1479, by E. Tasciotti and co-workers, through a "concealing" strategy: cloaking PLGA microspheres with the type I collagen matrix of a biomimetic scaffold, which enables the control of the production of inflammatory mediators. PMID:26970527

  18. Bone regeneration using a freeze-dried 3D gradient-structured scaffold incorporating OIC-A006-loaded PLGA microspheres based on β-TCP/PLGA.

    PubMed

    Lin, Liulan; Gao, Haitao; Dong, Yangyang

    2015-01-01

    To reveal the latent capacity of the growth factor-like low-molecular-weight material OIC-A006 in tissue regeneration, it is essential to design a porous scaffold in order to concurrently accommodate cells and drug release in a controlled manner. Consequently, we fabricated poly (L-lactide-co-glycolide) (PLGA)-based microspheres with an OIC-A006-loaded gradient-structured β-TCP/PLGA scaffold by freeze-drying which could then be used for drug delivery and bone regeneration. The OIC-A006-loaded β-TCP/PLGA scaffold consisted of two parts which loaded different doses of OIC-A006 (6.25 μM, outside; 12.5 μM, inside). The porosity, compressive strength, SEM, degradation, and cumulative amount of drug release in vitro were characterized. Furthermore, we confirmed the incorporation of OIC-A006 into the PLGA-based microspheres within the scaffolds using UV-spectrophotometry, and the amount of drug remaining in the scaffold was maintained by 10 % for up to 28 days. The drug release was slower in the normal-structured drug-loaded scaffold. The OIC-A006 released action from the OIC-A006-loaded β-TCP/PLGA scaffold with ideal therapeutic prospects in tissue regeneration. In vitro cell culture results showed that this gradient-structured composite scaffold can induce the adhesion and proliferation of rat bone marrow stromal cells towards osteoblasts. These results showed that the newly developed OIC-A006-loaded scaffolds with gradient structure can be potentially applied to bone regeneration in clinical applications. PMID:25577209

  19. Properties and applications of a pitch carbon microsphere composite

    NASA Technical Reports Server (NTRS)

    Price, H. L.; Nelson, J. B.

    1977-01-01

    Some properties and applications of a pitch carbon microsphere composite are described. The small hollow microspheres are made from the pitch which is usually a wasted by-product of petroleum refining. In contrast to high density composites or syntactic foams in which microspheres are inclusions within a continuous matrix, this composite is an aggregate of microspheres bonded together by a small amount of thermosetting polymer which does not form a continuous matrix. The result is a composite with low density and thermal expansion, modest strength and rigidity, and high porosity and carbon content. Mechanical, thermal, and sorption properties have been measured. Applications of the composite include honeycomb filler for high temperature or ionizing radiation fields and a wicking absorber for solar-powered stills.

  20. The in vivo performance of CaP/PLGA composites with varied PLGA microsphere sizes and inorganic compositions.

    PubMed

    Hoekstra, Jan Willem M; Ma, Jinling; Plachokova, Adelina S; Bronkhorst, Ewald M; Bohner, Marc; Pan, Juli; Meijer, Gert J; Jansen, John A; van den Beucken, Jeroen J J P

    2013-07-01

    Enrichment of calcium phosphate (CaP) bone substitutes with poly(lactic-co-glycolic acid) (PLGA) microspheres to create porosity overcomes the problem of poor CaP degradation. The degradation of CaP-PLGA composites can be customized by changing the physical and chemical properties of PLGA and/or CaP. However, the effect of the size of dense (solid rather than hollow) PLGA microspheres in CaP has not previously been described. The present study aimed at determining the effect of different dense (i.e. solid) PLGA microsphere sizes (small (S) ~20μm vs. large (L) ~130μm) and of CaP composition (CaP with either anhydrous dicalcium phosphate (DCP) or calcium sulphate dihydrate (CSD)) on CaP scaffold biodegradability and subsequent bone in-growth. To this end mandibular defects in minipigs were filled with pre-set CaP-PLGA implants, with autologous bone being used as a control. After 4weeks the autologous bone group outperformed all CaP-PLGA groups in terms of the amount of bone present at the defect site. On the other hand, at 12weeks substantial bone formation was observed for all CaP-PLGA groups (ranging from 47±25% to 62±15%), showing equal amounts of bone compared with the autologous bone group (82±9%), except for CaP with DCP and large PLGA microspheres (47±25%). It was concluded that in the current study design the difference in PLGA microsphere size and CaP composition led to similar results with respect to scaffold degradation and subsequent bone in-growth. Further, after 12weeks all CaP-PLGA composites proved to be effective for bone substitution. PMID:23511808

  1. 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.

  2. Biomimetic Concealing of PLGA Microspheres in a 3D Scaffold to Prevent Macrophage Uptake.

    PubMed

    Minardi, Silvia; Corradetti, Bruna; Taraballi, Francesca; Sandri, Monica; Martinez, Jonathan O; Powell, Sebastian T; Tampieri, Anna; Weiner, Bradley K; Tasciotti, Ennio

    2016-03-01

    Scaffolds functionalized with delivery systems for the release of growth factors is a robust strategy to enhance tissue regeneration. However, after implantation, macrophages infiltrate the scaffold, eventually initiating the degradation and clearance of the delivery systems. Herein, it is hypothesized that fully embedding the poly(d,l-lactide-co-glycolide acid) microspheres (MS) in a highly structured collagen-based scaffold (concealing) can prevent their detection, preserving the integrity of the payload. Confocal laser microscopy reveals that non-embedded MS are easily internalized; when concealed, J774 and bone marrow-derived macrophages (BMDM) cannot detect them. This is further demonstrated by flow cytometry, as a tenfold decrease is found in the number of MS engulfed by the cells, suggesting that collagen can cloak the MS. This correlates with the amount of nitric oxide and tumor necrosis factor-α produced by J774 and BMDM in response to the concealed MS, comparable to that found for non-functionalized collagen scaffolds. Finally, the release kinetics of a reporter protein is preserved in the presence of macrophages, only when MS are concealed. The data provide detailed strategies for fabricating three dimensional (3D) biomimetic scaffolds able to conceal delivery systems and preserve the therapeutic molecules for release. PMID:26797709

  3. Hydrogel Composite Materials for Tissue Engineering Scaffolds

    NASA Astrophysics Data System (ADS)

    Shapiro, Jenna M.; Oyen, Michelle L.

    2013-04-01

    Hydrogels are appealing for biomaterials applications due to their compositional similarity with highly hydrated natural biological tissues. However, for structurally demanding tissue engineering applications, hydrogel use is limited by poor mechanical properties. Here, composite materials approaches are considered for improving hydrogel properties while attempting to more closely mimic natural biological tissue structures. A variety of composite material microstructures is explored, based on multiple hydrogel constituents, particle reinforcement, electrospun nanometer to micrometer diameter polymer fibers with single and multiple fiber networks, and combinations of these approaches to form fully three-dimensional fiber-reinforced hydrogels. Natural and synthetic polymers are examined for formation of a range of scaffolds and across a range of engineered tissue applications. Following a discussion of the design and fabrication of composite scaffolds, interactions between living biological cells and composite scaffolds are considered across the full life cycle of tissue engineering from scaffold fabrication to in vivo use. We conclude with a summary of progress in this area to date and make recommendations for continuing research and for advanced hydrogel scaffold development.

  4. Spinal cord injury repair by implantation of structured hyaluronic acid scaffold with PLGA microspheres in the rat.

    PubMed

    Wen, Yujun; Yu, Shukui; Wu, Yanhong; Ju, Rongkai; Wang, Hao; Liu, Yujun; Wang, Ying; Xu, Qunyuan

    2016-04-01

    In order to create an optimal microenvironment for neural regeneration in the lesion area after spinal cord injury (SCI), we fabricated a novel scaffold composed of a hyaluronic acid (HA) hydrogel with a longitudinal multi-tubular conformation. The scaffold was modified by binding with an anti-Nogo receptor antibody (antiNgR) and mixed further with poly(lactic-co-glycolic acid) (PLGA) microspheres containing brain-derived neurotrophic factor and vascular endothelial growth factor (HA+PLGA). In the rat, after implantation of this composite into an injured area created by a dorsal hemisection at T9-10 of the spinal cord, favorable effects were seen with regard to the promotion of spinal repair, including excellent integration of the implants with host tissue, inhibition of inflammation, and gliosis. In particular, large numbers of new blood vessels and regenerated nerve fibers were found within and around the implants. Simultaneously, the implanted rats exhibited improved locomotor recovery. Thus, this novel composite material might provide a suitable microenvironment for neural regeneration following SCI. PMID:26463048

  5. Stratified scaffold design for engineering composite tissues.

    PubMed

    Mosher, Christopher Z; Spalazzi, Jeffrey P; Lu, Helen H

    2015-08-01

    A significant challenge to orthopaedic soft tissue repair is the biological fixation of autologous or allogeneic grafts with bone, whereby the lack of functional integration between such grafts and host bone has limited the clinical success of anterior cruciate ligament (ACL) and other common soft tissue-based reconstructive grafts. The inability of current surgical reconstruction to restore the native fibrocartilaginous insertion between the ACL and the femur or tibia, which minimizes stress concentration and facilitates load transfer between the soft and hard tissues, compromises the long-term clinical functionality of these grafts. To enable integration, a stratified scaffold design that mimics the multiple tissue regions of the ACL interface (ligament-fibrocartilage-bone) represents a promising strategy for composite tissue formation. Moreover, distinct cellular organization and phase-specific matrix heterogeneity achieved through co- or tri-culture within the scaffold system can promote biomimetic multi-tissue regeneration. Here, we describe the methods for fabricating a tri-phasic scaffold intended for ligament-bone integration, as well as the tri-culture of fibroblasts, chondrocytes, and osteoblasts on the stratified scaffold for the formation of structurally contiguous and compositionally distinct regions of ligament, fibrocartilage and bone. The primary advantage of the tri-phasic scaffold is the recapitulation of the multi-tissue organization across the native interface through the layered design. Moreover, in addition to ease of fabrication, each scaffold phase is similar in polymer composition and therefore can be joined together by sintering, enabling the seamless integration of each region and avoiding delamination between scaffold layers. PMID:25846397

  6. Thermal expansion of an epoxy-glass microsphere composite

    NASA Technical Reports Server (NTRS)

    Price, H. L.; Burks, H. D.

    1977-01-01

    The thermal expansion of a composite of epoxy (diglycidyl ether of bisphenol A) and solid glass microspheres was investigated. The microspheres had surfaces which were either untreated or treated with a silicone release agent, an epoxy coupling agent, or a general purpose silane coupling agent. Both room temperature (about 300 K) and elevated temperature (about 475 K) cures were used for the epoxy. Two microsphere size ranges were used, about 50 microns, which is applicable in filled moldings, and about 125 microns, which is applicable as bond line spacers. The thermal expansion of the composites was measured from 300 to 350 K or from 300 to 500 K, depending on the epoxy cure temperature. Measurements were made on composites containing up to .6 volume fraction microspheres. Two predictive models, which required only the values of thermal expansion of the polymer and glass and their specific gravities, were tested against the experimental data. A finite element analysis was made of the thermal strain of a composite cell containing a single microsphere surrounded by a finite-thickness interface.

  7. Composite tissue engineering on polycaprolactone nanofiber scaffolds.

    PubMed

    Reed, Courtney R; Han, Li; Andrady, Anthony; Caballero, Montserrat; Jack, Megan C; Collins, James B; Saba, Salim C; Loboa, Elizabeth G; Cairns, Bruce A; van Aalst, John A

    2009-05-01

    Tissue engineering has largely focused on single tissue-type reconstruction (such as bone); however, the basic unit of healing in any clinically relevant scenario is a compound tissue type (such as bone, periosteum, and skin). Nanofibers are submicron fibrils that mimic the extracellular matrix, promoting cellular adhesion, proliferation, and migration. Stem cell manipulation on nanofiber scaffolds holds significant promise for future tissue engineering. This work represents our initial efforts to create the building blocks for composite tissue reflecting the basic unit of healing. Polycaprolactone (PCL) nanofibers were electrospun using standard techniques. Human foreskin fibroblasts, murine keratinocytes, and periosteal cells (4-mm punch biopsy) harvested from children undergoing palate repair were grown in appropriate media on PCL nanofibers. Human fat-derived mesenchymal stem cells were osteoinduced on PCL nanofibers. Cell growth was assessed with fluorescent viability staining; cocultured cells were differentiated using antibodies to fibroblast- and keratinocyte-specific surface markers. Osteoinduction was assessed with Alizarin red S. PCL nanofiber scaffolds supported robust growth of fibroblasts, keratinocytes, and periosteal cells. Cocultured periosteal cells (with fibroblasts) and keratinocytes showed improved longevity of the keratinocytes, though growth of these cell types was randomly distributed throughout the scaffold. Robust osteoinduction was noted on PCL nanofibers. Composite tissue engineering using PCL nanofiber scaffolds is possible, though the major obstacles to the trilaminar construct are maintaining an appropriate interface between the tissue types and neovascularization of the composite structure. PMID:19387150

  8. 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

  9. Coaxial electrohydrodynamic atomization process for production of polymeric composite microspheres.

    PubMed

    Xu, Qingxing; Qin, Hao; Yin, Zhenyuan; Hua, Jinsong; Pack, Daniel W; Wang, Chi-Hwa

    2013-12-18

    Polymeric composite microspheres consisting of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(D,L-lactic acid) (PDLLA) shell layer were successfully fabricated by coaxial electrohydrodynamic atomization (CEHDA) process. Process conditions, including nozzle voltage and polymer solution flow rates, as well as solution parameters, such as polymer concentrations, were investigated to ensure the formation of composite microspheres with a doxorubicin-loaded PLGA core surrounded by a relatively drug-free PDLLA shell layer. Various microsphere formulations were fabricated and characterized in terms of their drug distribution, encapsulation efficiency and in vitro release. Numerical simulation of CEHDA process was performed based on a computational fluid dynamics (CFD) model in Fluent by employing the process conditions and fluid properties used in the experiments. The simulation results were compared with the experimental work to illustrate the capability of the CFD model to predict the production of consistent compound droplets, and hence, the expected core-shell structured microspheres. PMID:24347672

  10. Coaxial electrohydrodynamic atomization process for production of polymeric composite microspheres

    PubMed Central

    Xu, Qingxing; Qin, Hao; Yin, Zhenyuan; Hua, Jinsong; Pack, Daniel W.; Wang, Chi-Hwa

    2013-01-01

    Polymeric composite microspheres consisting of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(D,L-lactic acid) (PDLLA) shell layer were successfully fabricated by coaxial electrohydrodynamic atomization (CEHDA) process. Process conditions, including nozzle voltage and polymer solution flow rates, as well as solution parameters, such as polymer concentrations, were investigated to ensure the formation of composite microspheres with a doxorubicin-loaded PLGA core surrounded by a relatively drug-free PDLLA shell layer. Various microsphere formulations were fabricated and characterized in terms of their drug distribution, encapsulation efficiency and in vitro release. Numerical simulation of CEHDA process was performed based on a computational fluid dynamics (CFD) model in Fluent by employing the process conditions and fluid properties used in the experiments. The simulation results were compared with the experimental work to illustrate the capability of the CFD model to predict the production of consistent compound droplets, and hence, the expected core-shell structured microspheres. PMID:24347672

  11. Functionally modified gelatin microspheres impregnated collagen scaffold as novel wound dressing to attenuate the proteases and bacterial growth.

    PubMed

    Adhirajan, N; Shanmugasundaram, N; Shanmuganathan, S; Babu, Mary

    2009-02-15

    An attempt was made to develop a new therapeutic delivery system which would play a dual role of attenuating MMP activity in the wounds and also prevent infection by controlled delivery of antimicrobials. A catechol type MMP inhibitor 2,3-dihydroxybenzoic acid (DHBA) was conjugated to gelatin microspheres using EDC/NHS as coupling agents. The potential of the modified gelatin microspheres (DHB-MS) to attenuate the proteases such as MMP 2 and MMP 9 in the diabetic wound tissues was investigated by gelatin zymography. Further the modified microspheres were loaded with doxycycline and impregnated in a reconstituted collagen scaffold as novel wound dressing. The in vitro release behavior of doxycycline from both DHB-MS and DHB-MS impregnated collagen scaffold was investigated. DHB-MS when incubated with the tissue lysate for 6h displayed the complete inhibition of the MMPs in the tissue lysate. The in vitro drug release studies from the collagen scaffold exhibited the burst release of 44%, exerted immediate chemo prophylaxis and sustained delivery for 72 h. The MTT assay and fluorescent labeling with calcein AM indicated that the DHB-MS is biocompatible to human foreskin fibroblasts. Thus the system developed provides wider scope to control the pathogens involved in infection and also the excess matrix degradation. PMID:18952165

  12. Preparation of bioactive porous HA/PCL composite scaffolds

    NASA Astrophysics Data System (ADS)

    Zhao, J.; Guo, L. Y.; Yang, X. B.; Weng, J.

    2008-12-01

    Porous hydroxyapatite (HA) bioceramic scaffold has been widely attracted the attention to act as a three-dimensional (3D) template for cell adhesion, proliferation, differentiation and thus promoting bone and cartilage regeneration because of its osteoinduction. However, the porous bioceramic scaffold is fragile so that it is not suitable to be applied in clinic for bone repair or replacement. Therefore, it is significant to improve the mechanical property of porous HA bioceramics while the interconnected structure is maintained for tissue ingrowth in vivo. In the present research, a porous composite scaffold composed of HA scaffold and polycaprolactone (PCL) lining was fabricated by the method of polymer impregnating to produce HA scaffold coated with PCL lining. Subsequently, the composite scaffolds were deposited with biomimetic coating for improving the bioactivity. The HA/PCL composite scaffolds with improved mechanical property and bioactivity is expected to be a promising bone substitute in tissue engineering applications.

  13. Mineralization, biodegradation, and drug release behavior of gelatin/apatite composite microspheres for bone regeneration.

    PubMed

    Leeuwenburgh, Sander C G; Jo, Junichiro; Wang, Huanan; Yamamoto, Masaya; Jansen, John A; Tabata, Yasuhiko

    2010-10-11

    Gelatin microspheres are well-known for their capacity to release growth factors in a controlled manner, but gelatin microspheres do not calcify in the absence of so-called bioactive substances that induce deposition of calcium phosphate (CaP) bone mineral. This study has investigated if CaP nanocrystals can be incorporated into gelatin microspheres to render these inert microspheres bioactive without compromising the drug releasing properties of gelatin microspheres. Incorporation of CaP nanocrystals into gelatin microspheres resulted into reduced biodegradation and drug release rates, whereas their calcifying capacity increased strongly compared to inert gelatin microspheres. The reduced drug release rate was correlated to the reduced degradation rate as caused by a physical cross-linking effect of CaP nanocrystals dispersed in the gelatin matrix. Consequently, these composite microspheres combine beneficial drug-releasing properties of organic gelatin with the calcifying capacity of a dispersed CaP phase. PMID:20804200

  14. Mesoporous metal oxide microsphere electrode compositions and their methods of making

    DOEpatents

    Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A; Brown, Gilbert M

    2014-12-16

    Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions comprise (a) microspheres with an average diameter between 200 nanometers (nm) and 10 micrometers (.mu.m); (b) mesopores on the surface and interior of the microspheres, wherein the mesopores have an average diameter between 1 nm and 50 nm and the microspheres have a surface area between 50 m.sup.2/g and 500 m.sup.2/g, and wherein the composition has an electrical conductivity of at least 1.times.10.sup.-7 S/cm at 25.degree. C. and 60 MPa. The methods of making comprise forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least one method selected from the group consisting of: (i) annealing in a reducing atmosphere, (ii) doping with an aliovalent element, and (iii) coating with a coating composition.

  15. 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.

  16. Fluorescent composite scaffolds made of nanodiamonds/polycaprolactone

    NASA Astrophysics Data System (ADS)

    Cao, Li; Hou, Yanwen; Lafdi, Khalid; Urmey, Kirk

    2015-11-01

    Polycaprolactone (PCL) has been widely studied for biological applications. Biodegradable PCL fibrous scaffold can work as an appropriate substrate for tissue regeneration. In this letter, fluorescent nanodiamonds (FNDs) were prepared after surface passivation with octadecylamine. The FNDs were then mixed with PCL polymer and subsequently electrospun into FNDs/PCL fibrous scaffolds. The obtained scaffolds not only exhibited photoluminescence, but also showed reinforced mechanical strength. Toxicity study indicated FNDs/PCL scaffolds were nontoxic. This biocompatible fluorescent composite fibrous scaffold can support in vitro cell growth and also has the potential to act as an optical probe for tissue engineering application in vitro and in vivo.

  17. Preparation of monodisperse PEG hydrogel composite microspheres via microfluidic chip with rounded channels

    NASA Astrophysics Data System (ADS)

    Yu, Bing; Cong, Hailin; Liu, Xuesong; Ren, Yumin; Wang, Jilei; Zhang, Lixin; Tang, Jianguo; Ma, Yurong; Akasaka, Takeshi

    2013-09-01

    An effective microfluidic method to fabricate monodisperse polyethylene glycol (PEG) hydrogel composite microspheres with tunable dimensions and properties is reported in this paper. A T-junction microfluidic chip equipped with rounded channels and online photopolymerization system is applied for the microsphere microfabrication. The shape and size of the microspheres are well controlled by the rounded channels and PEG prepolymer/silicon oil flow rate ratios. The obtained PEG/aspirin composite microspheres exhibit a sustained release of aspirin for a wide time range; the obtained PEG/Fe3O4 nanocomposite microspheres exhibit excellent magnetic properties; and the obtained binary PEG/dye composite microspheres show the ability to synchronously load two functional components in the same peanut-shaped or Janus hydrogel particles.

  18. Facile fabrication of poly(L-lactic acid) microsphere-incorporated calcium alginate/hydroxyapatite porous scaffolds based on Pickering emulsion templates.

    PubMed

    Hu, Yang; Ma, Shanshan; Yang, Zhuohong; Zhou, Wuyi; Du, Zhengshan; Huang, Jian; Yi, Huan; Wang, Chaoyang

    2016-04-01

    In this study, we develop a facile one-pot approach to the fabrication of poly(L-lactic acid) (PLLA) microsphere-incorporated calcium alginate (ALG-Ca)/hydroxyapatite (HAp) porous scaffolds based on HAp nanoparticle-stabilized oil-in-water Pickering emulsion templates, which contain alginate in the aqueous phase and PLLA in the oil phase. The emulsion aqueous phase is solidified by in situ gelation of alginate with Ca(2+) released from HAp by decreasing pH with slow hydrolysis of d-gluconic acid δ-lactone (GDL) to produce emulsion droplet-incorporated gels, followed by freeze-drying to form porous scaffolds containing microspheres. The pore structure of porous scaffolds can be adjusted by varying the HAp or GDL concentration. The compressive tests show that the increase of HAp or GDL concentration is beneficial to improve the compressive property of porous scaffolds, while the excessive HAp can lead to the decrease in compressive property. Moreover, the swelling behavior studies display that the swelling ratios of porous scaffolds reduce with increasing HAp or GDL concentration. Furthermore, hydrophobic drug ibuprofen (IBU) and hydrophilic drug bovine serum albumin (BSA) are loaded into the microspheres and scaffold matrix, respectively. In vitro drug release results indicate that BSA has a rapid release while IBU has a sustained release in the dual drug-loaded scaffolds. In vitro cell culture experiments verify that mouse bone mesenchymal stem cells can proliferate on the porous scaffolds well, indicating the good biocompatibility of porous scaffolds. All these results demonstrate that the PLLA microsphere-incorporated ALG-Ca/HAp porous scaffolds have a promising potential for tissue engineering and drug delivery applications. PMID:26774574

  19. Chitosan-chitin nanocrystal composite scaffolds for tissue engineering.

    PubMed

    Liu, Mingxian; Zheng, Huanjun; Chen, Juan; Li, Shuangli; Huang, Jianfang; Zhou, Changren

    2016-11-01

    Chitin nanocrystals (CNCs) with length and width of 300 and 20nm were uniformly dispersed in chitosan (CS) solution. The CS/CNCs composite scaffolds prepared utilizing a dispersion-based freeze dry approach exhibit significant enhancement in compressive strength and modulus compared with pure CS scaffold both in dry and wet state. A well-interconnected porous structure with size in the range of 100-200μm and over 80% porosity are found in the composite scaffolds. The crystal structure of CNCs is retained in the composite scaffolds. The incorporation of CNCs leads to increase in the scaffold density and decrease in the water swelling ratio. Moreover, the composite scaffolds are successfully applied as scaffolds for MC3T3-E1 osteoblast cells, showing their excellent biocompatibility and low cytotoxicity. The results of fluorescent micrographs images reveal that CNCs can markedly promote the cell adhesion and proliferation of the osteoblast on CS. The biocompatible composite scaffolds with enhanced mechanical properties have potential application in bone tissue engineering. PMID:27516335

  20. Poly(lactic-co-glycolic) Acid/Nanohydroxyapatite Scaffold Containing Chitosan Microspheres with Adrenomedullin Delivery for Modulation Activity of Osteoblasts and Vascular Endothelial Cells

    PubMed Central

    Li, Chunyan; Chen, Yingxin; Dong, Shujun; Chen, Xuesi; Zhou, Yanmin

    2013-01-01

    Adrenomedullin (ADM) is a bioactive regulatory peptide that affects migration and proliferation of diverse cell types, including endothelial cells, smooth muscle cells, and osteoblast-like cells. This study investigated the effects of sustained release of ADM on the modulation activity of osteoblasts and vascular endothelial cells in vitro. Chitosan microspheres (CMs) were developed for ADM delivery. Poly(lactic-co-glycolic) acid and nano-hydroxyapatite were used to prepare scaffolds containing microspheres with ADM. The CMs showed rough surface morphology and high porosity, and they were well-distributed. The scaffolds exhibited relatively uniform pore sizes with interconnected pores. The addition of CMs improved the mechanical properties of the scaffolds without affecting their high porosity. In vitro degradation tests indicated that the addition of CMs increased the water absorption of the scaffolds and inhibited pH decline of phosphate-buffered saline medium. The expression levels of osteogenic-related and angiogenic-related genes were determined in MG63 cells and in human umbilical vein endothelial cells cultured on the scaffolds, respectively. The expression levels of osteogenic-related and angiogenic-related proteins were also detected by western blot analysis. Their expression levels in cells were improved on the ADM delivery scaffolds at a certain time point. The in vitro evaluation suggests that the microsphere-scaffold system is suitable as a model for bone tissue engineering. PMID:23841075

  1. 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. PMID:26478351

  2. Preparation and characterization of bioactive mesoporous wollastonite - Polycaprolactone composite scaffold.

    PubMed

    Wei, Jie; Chen, Fangping; Shin, Jung-Woog; Hong, Hua; Dai, Chenglong; Su, Jiancan; Liu, Changsheng

    2009-02-01

    A well-defined mesoporous structure of wollastonite with high specific surface area was synthesized using surfactant P123 (triblock copolymer) as template, and its composite scaffolds with poly(epsilon-caprolactone) (PCL) were fabricated by a simple method of solvent casting-particulate leaching. The measurements of the water contact angles suggest that the incorporation of either mesoporous wollastonite (m-WS) or conventional wollastonite (c-WS) into PCL could improve the hydrophilicity of the composites, and the former was more effective than the later. The bioactivity of the composite scaffold was evaluated by soaking the scaffolds in a simulated body fluid (SBF) and the results show that the m-WS/PCL composite (m-WPC) scaffolds can induce a dense and continuous layer of apatite after soaking for 1 week, as compared with the scattered and discrete apatite particles on the c-WS/PCL composite (c-WPC) scaffolds. The m-WPC had a significantly enhanced apatite-forming bioactivity compared with the c-WPC owing to the high specific surface area and pore volume of m-WS. In addition, attachment and proliferation of MG(63) cells on m-WPC scaffolds were significantly higher than that of c-WPC, revealing that m-WPC scaffolds had excellent biocompatibility. Such improved properties of m-WPC should be helpful for developing new biomaterials and may have potential use in hard tissue repair. PMID:19019424

  3. Controlled degradation pattern of hydroxyapatite/calcium carbonate composite microspheres.

    PubMed

    Yang, Ning; Zhong, Qiwei; Zhou, Ying; Kundu, Subhas C; Yao, Juming; Cai, Yurong

    2016-06-01

    Hydroxyapatite (HAP) is widely used in clinic due to its good biocompatibility and osteoconductivity except for its slow degradation speed. In the present study, spherical calcium carbonate (CaCO3 ) is fabricated in the presence of silk protein sericin, which is transmuted into HAP microsphere in phosphate solution with the assistance of microwave irradiation. The effect of reaction conditions on the conversion of CaCO3 is investigated including reaction time, chemical composition of phosphate solution, and microwave power to get a series of HAP/CaCO3 composites. The degradation property of the composites is evaluated in vitro. Results show the degradation speed of the composite with higher HAP content is slower. The degradation rate of the composite could be changed effectively by modulating the proportion of HAP and CaCO3 . This work provides a feasible method for the preparation of spherical HAP/CaCO3 composite with controllable degradability. The composite thus obtained may be an ideal material for bone tissue engineering application. Microsc. Res. Tech. 79:518-524, 2016. © 2016 Wiley Periodicals, Inc. PMID:27037606

  4. 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. PMID:27612706

  5. Poly-L-lactide/sodium alginate/chitosan microsphere hybrid scaffolds made with braiding manufacture and adhesion technique: Solution to the incongruence between porosity and compressive strength.

    PubMed

    Lin, Jia-Horng; Chen, Chih-Kuang; Wen, Shih-Peng; Lou, Ching-Wen

    2015-01-01

    Bone scaffolds require a three-dimensional structure, high porosity, interconnected pores, adequate mechanical strengths, and non-toxicity. A high porosity is incongruent with mechanical strengths. Therefore, this study combines a braiding method and microsphere solution to create bone scaffolds with a high porosity and sufficient mechanical strengths. First, poly-L-lactide (PLLA) plied yarns are braided into 5-, 10-, 15-, 20-, and 25-layer hollow braids, and then thermally treated at 165 °C for various durations. Next, sodium alginate (SA) microspheres, cross-linked with CaCl2 solution with various concentrations, are combined with PLLA porous braided bone scaffolds to form PLLA/SA/CS microsphere hybrid scaffolds, which are then observed for surface observation, and tested for porosity, water contact angle, compressive strength, MTT assay, bioactivity, alkaline phosphatase (ALP) assay, cell attachment, and statistical analyses. The test results show that the layer amount of the bone scaffold is proportional to the compressive strength. With the same number of layers, the compressive strength is inversely proportional to the concentration of the CaCl2 solution. The results of surface observation, porosity, and water contact angle tests show that PLLA/SA/CS microsphere hybrid scaffolds possess a high porosity and good hydrophilicity; as a result, the braiding manufacture and the bonding technique effectively solve the confliction between porosity and mechanical strength. The concentration of CaCl2 does not pertain to cell activity and ALP results, exemplified by good cell attachment on bone scaffolds for each specification. PMID:25953547

  6. 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

  7. Microstructure and properties of polyhydroxybutyrate-chitosan-nanohydroxyapatite composite scaffolds.

    PubMed

    Medvecky, L

    2012-01-01

    Polyhydroxybutyrate-chitosan-hydroxyapatite (PHB-CHT-HAP) composite scaffolds were prepared by the precipitation of biopolymer-nanohydroxyapatite suspensions and following lyophilisation. The propylene carbonate and acetic acid were used as the polyhydroxybutyrate and chitosan solvents, respectively. The high porous microstructure was observed in composites and the macroporosity of scaffolds (pore sizes up to 100 μm) rose with the chitosan content. It was found the reduction in both the PHB melting (70°C) and thermal degradation temperatures of polyhydroxybutyrate and chitosan biopolymers in composites, which confirms the mutual ineraction between polymers and the decrease of PHB lamellar thickness. No preferential preconcentration of individual biopolymers was verified in composites, and the compressive strengths of macroporous PHB-CHT-HAP scaffolds were approximately 2.5 MPa. The high toxic fluorinated cosolvents were avoided from the preparation process. PMID:22547987

  8. Microstructure and Properties of Polyhydroxybutyrate-Chitosan-Nanohydroxyapatite Composite Scaffolds

    PubMed Central

    Medvecky, L.

    2012-01-01

    Polyhydroxybutyrate-chitosan-hydroxyapatite (PHB-CHT-HAP) composite scaffolds were prepared by the precipitation of biopolymer-nanohydroxyapatite suspensions and following lyophilisation. The propylene carbonate and acetic acid were used as the polyhydroxybutyrate and chitosan solvents, respectively. The high porous microstructure was observed in composites and the macroporosity of scaffolds (pore sizes up to 100 μm) rose with the chitosan content. It was found the reduction in both the PHB melting (70°C) and thermal degradation temperatures of polyhydroxybutyrate and chitosan biopolymers in composites, which confirms the mutual ineraction between polymers and the decrease of PHB lamellar thickness. No preferential preconcentration of individual biopolymers was verified in composites, and the compressive strengths of macroporous PHB-CHT-HAP scaffolds were approximately 2.5 MPa. The high toxic fluorinated cosolvents were avoided from the preparation process. PMID:22547987

  9. Coaxial additive manufacture of biomaterial composite scaffolds for tissue engineering.

    PubMed

    Cornock, R; Beirne, S; Thompson, B; Wallace, G G

    2014-06-01

    An inherent difficulty associated with the application of suitable bioscaffolds for tissue engineering is the incorporation of adequate mechanical characteristics into the materials which recapitulate that of the native tissue, whilst maintaining cell proliferation and nutrient transfer qualities. Biomaterial composites fabricated using rapid prototyping techniques can potentially improve the functionality and patient-specific processing of tissue engineering scaffolds. In this work, a technique for the coaxial melt extrusion printing of core-shell scaffold structures was designed, implemented and assessed with respect to the repeatability, cell efficacy and scaffold porosity obtainable. Encapsulated alginate hydrogel/thermoplastic polycaprolactone (Alg-PCL) cofibre scaffolds were fabricated. Selective laser melting was used to produce a high resolution stainless steel 316 L coaxial extrusion nozzle, exhibiting diameters of 300 μm/900 μm for the inner and outer nozzles respectively. We present coaxial melt extrusion printed scaffolds of Alg-PCL cofibres with ~0.4 volume fraction alginate, with total fibre diameter as low as 600 μm and core material offset as low as 10% of the total diameter. Furthermore the tuneability of scaffold porosity, pore size and interconnectivity, as well as the preliminary inclusion, compatibility and survival of an L-929 mouse fibroblast cell-line within the scaffolds were explored. This preliminary cell work highlighted the need for optimal material selection and further design reiteration in future research. PMID:24658021

  10. Citric acid-based hydroxyapatite composite scaffolds enhance calvarial regeneration.

    PubMed

    Sun, Dawei; Chen, Yuhui; Tran, Richard T; Xu, Song; Xie, Denghui; Jia, Chunhong; Wang, Yuchen; Guo, Ying; Zhang, Zhongmin; Guo, Jinshan; Yang, Jian; Jin, Dadi; Bai, Xiaochun

    2014-01-01

    Citric acid-based polymer/hydroxyapatite composites (CABP-HAs) are a novel class of biomimetic composites that have recently attracted significant attention in tissue engineering. The objective of this study was to compare the efficacy of using two different CABP-HAs, poly (1,8-octanediol citrate)-click-HA (POC-Click-HA) and crosslinked urethane-doped polyester-HA (CUPE-HA) as an alternative to autologous tissue grafts in the repair of skeletal defects. CABP-HA disc-shaped scaffolds (65 wt.-% HA with 70% porosity) were used as bare implants without the addition of growth factors or cells to renovate 4 mm diameter rat calvarial defects (n = 72, n = 18 per group). Defects were either left empty (negative control group), or treated with CUPE-HA scaffolds, POC-Click-HA scaffolds, or autologous bone grafts (AB group). Radiological and histological data showed a significant enhancement of osteogenesis in defects treated with CUPE-HA scaffolds when compared to POC-Click-HA scaffolds. Both, POC-Click-HA and CUPE-HA scaffolds, resulted in enhanced bone mineral density, trabecular thickness, and angiogenesis when compared to the control groups at 1, 3, and 6 months post-trauma. These results show the potential of CABP-HA bare implants as biocompatible, osteogenic, and off-shelf-available options in the repair of orthopedic defects. PMID:25372769

  11. Controlled release and gradient formation of human glial-cell derived neurotrophic factor from heparinated poly(ethylene glycol) microsphere-based scaffolds.

    PubMed

    Roam, Jacob L; Nguyen, Peter K; Elbert, Donald L

    2014-08-01

    Introduction of spatial patterning of proteins, while retaining activity and releasability, is critical for the field of regenerative medicine. Reversible binding to heparin, which many biological molecules exhibit, is one potential pathway to achieve this goal. We have covalently bound heparin to poly(ethylene glycol) (PEG) microspheres to create useful spatial patterns of glial-cell derived human neurotrophic factor (GDNF) in scaffolds to promote peripheral nerve regeneration. Labeled GDNF was incubated with heparinated microspheres that were subsequently centrifuged into cylindrical scaffolds in distinct layers containing different concentrations of GDNF. The GDNF was then allowed to diffuse out of the scaffold, and release was tracked via fluorescent scanning confocal microscopy. The measured release profile was compared to predicted Fickian models. Solutions of reaction-diffusion equations suggested the concentrations of GDNF in each discrete layer that would result in a nearly linear concentration gradient over much of the length of the scaffold. The agreement between the predicted and measured GDNF concentration gradients was high. Multilayer scaffolds with different amounts of heparin and GDNF and different crosslinking densities allow the design of a wide variety of gradients and release kinetics. Additionally, fabrication is much simpler and more robust than typical gradient-forming systems due to the low viscosity of the microsphere solutions compared to gelating solutions, which can easily result in premature gelation or the trapping of air bubbles with a nerve guidance conduit. The microsphere-based method provides a framework for producing specific growth factor gradients in conduits designed to enhance nerve regeneration. PMID:24816282

  12. Controlled Release and Gradient Formation of Human Glial-Cell Derived Neurotrophic Factor from Heparinated Poly(ethylene glycol) Microsphere-based Scaffolds

    PubMed Central

    Roam, Jacob L.; Nguyen, Peter K.; Elbert, Donald L.

    2014-01-01

    Introduction of spatial patterning of proteins, while retaining activity and releasability, is critical for the field of regenerative medicine. Reversible binding to heparin, which many biological molecules exhibit, is one potential pathway to achieving this goal. We have covalently bound heparin to poly(ethylene glycol) (PEG) microspheres to create useful spatial patterns of glial-cell derived human neurotrophic factor (GDNF) in scaffolds to promote peripheral nerve regeneration. Labeled GDNF was incubated with heparinated microspheres that were subsequently centrifuged into cylindrical scaffolds in distinct layers containing different concentrations of GDNF. The GDNF was then allowed to diffuse out of the scaffold, and release was tracked via fluorescent scanning confocal microscopy. The measured release profile was compared to predicted Fickian models. Solutions of reaction-diffusion equations suggested the concentrations of GDNF in each discrete layer that would result in a nearly linear concentration gradient over much of the length of the scaffold. The agreement between the predicted and measured GDNF concentration gradients was high. Multilayer scaffolds with different amounts of heparin and GDNF and different crosslinking densities allow the design of a wide variety of gradients and release kinetics. Additionally, fabrication is much simpler and more robust than typical gradient-forming systems due to the low viscosity of the microsphere solutions compared to gelating solutions, which can easily result in premature gelation or the trapping of air bubbles with a nerve guidance conduit. The microsphere-based method provides a framework for producing specific growth factor gradients in conduits designed to enhance nerve regeneration. PMID:24816282

  13. Stimuli-responsive transformation in carbon nanotube/expanding microsphere-polymer composites

    PubMed Central

    Loomis, James; Xu, Peng; Panchapakesan, Balaji

    2013-01-01

    Our work introduces a class of stimuli-responsive expanding polymer composites with ability to unidirectionally transform physical dimensions, elastic modulus, density, and electrical resistance. Carbon nanotubes and core-shell acrylic microspheres were dispersed in polydimethylsiloxane, resulting in composites that exhibit a binary set of material properties. Upon thermal or infrared stimuli, liquid cores encapsulated within the microspheres vaporize, expanding the surrounding shells and stretching the matrix. Microsphere expansion results in visible dimensional changes, regions of reduced polymeric chain mobility, nanotube tensioning, and overall elastic to plastic-like transformation of the composite. Here we show composite transformations including macroscopic volume expansion (>500%), density reduction (>80%), and elastic modulus increase (>675%). Additionally, conductive nanotubes allow for remote expansion monitoring and exhibit distinct loading-dependent electrical responses. With ability to pattern regions of tailorable expansion, strength, and electrical resistance into a single polymer skin, these composites present opportunities as structural and electrical building blocks in smart systems. PMID:23574648

  14. Comparative Investigation on Thermal Insulation of Polyurethane Composites Filled with Silica Aerogel and Hollow Silica Microsphere.

    PubMed

    Liu, Chunyuan; Kim, Jin Seuk; Kwon, Younghwan

    2016-02-01

    This paper presents a comparative study on thermal conductivity of PU composites containing open-cell nano-porous silica aerogel and closed-cell hollow silica microsphere, respectively. The thermal conductivity of PU composites is measured at 30 degrees C with transient hot bridge method. The insertion of polymer in pores of silica aerogel creates mixed interfaces, increasing the thermal conductivity of resulting composites. The measured thermal conductivity of PU composites filled with hollow silica microspheres is estimated using theoretical models, and is in good agreement with Felske model. It appears that the thermal conductivity of composites decreases with increasing the volume fraction (phi) when hollow silica microsphere (eta = 0.916) is used. PMID:27433652

  15. Fabrication of chitin-chitosan/nano TiO2-composite scaffolds for tissue engineering applications.

    PubMed

    Jayakumar, R; Ramachandran, Roshni; Divyarani, V V; Chennazhi, K P; Tamura, H; Nair, S V

    2011-03-01

    In this study, we prepared chitin-chitosan/nano TiO(2) composite scaffolds using lyophilization technique for bone tissue engineering. The prepared composite scaffold was characterized using SEM, XRD, FTIR and TGA. In addition, swelling, degradation and biomineralization capability of the composite scaffolds were evaluated. The developed composite scaffold showed controlled swelling and degradation when compared to the control scaffold. Cytocompatibility of the scaffold was assessed by MTT assay and cell attachment studies using osteoblast-like cells (MG-63), fibroblast cells (L929) and human mesenchymal stem cells (hMSCs). Results indicated no sign of toxicity and cells were found attached to the pore walls within the scaffolds. These results suggested that the developed composite scaffold possess the prerequisites for tissue engineering scaffolds and it can be used for tissue engineering applications. PMID:21182857

  16. Facile large scale preparation and electromagnetic properties of silica-nickel-carbon composite shelly hollow microspheres.

    PubMed

    An, Zhenguo; Zhang, Jingjie

    2016-02-21

    Silica-nickel-carbon composite microspheres with shelly hollow structures and tunable electromagnetic properties were prepared in large scale through a three-step route. Micron-sized precursor microspheres were prepared firstly by spray drying of water glass. Then a subsequent acid leaching with diluted hydrochloric acid was carried out to eliminate the Na2O in the precursor microspheres to get single shell silica hollow microspheres (SHMs). Afterwards, Ni-C composite shells were assembled on the surface of the previously formed SHMs through a calcination route in an inert atmosphere to form silica-nickel-carbon composite shelly hollow microspheres (CSHMs) through decomposition of the reactants and carbon thermal reduction. By properly tuning the calcination conditions, silica-nickel CSHMs with gradients in composition can also be prepared. The electromagnetic properties of the CSHMs were studied and the results demonstrate that they present ferromagnetic and microwave absorbing properties related to the shell composition. The DSHPs thus obtained may have some promising applications in the fields of low-density magnetic materials and microwave absorbers. This work provides a new strategy to fabricate shelly hollow particles, which can be expected to be extended to the controlled preparation of similar structures with various compositions. PMID:26726765

  17. Perforated Metal Oxide-Carbon Nanotube Composite Microspheres with Enhanced Lithium-Ion Storage Properties.

    PubMed

    Choi, Seung Ho; Lee, Jong-Heun; Kang, Yun Chan

    2015-10-27

    Metal oxide-carbon nanotube (CNT) composite microspheres with a novel structure were fabricated using a one-step spray pyrolysis process. Metal oxide-CNT composite microspheres with a uniform distribution of void nanospheres were prepared from a colloidal spray solution containing CNTs, metal salts, and polystyrene (PS) nanobeads. Perforated SnO2-CNT composite microspheres with a uniform distribution of void nanospheres showed excellent lithium storage properties as anode materials for lithium-ion batteries. Bare SnO2 microspheres and SnO2-CNT composite microspheres with perforated and filled structures had a discharge capacity of 450, 1108, and 590 mA h g(-1) for the 250th cycle at a current density of 1.5 A g(-1), and the corresponding capacity retention compared to the second cycle was 41, 98, and 55%, respectively. The synergetic combination of void nanospheres and flexible CNTs improved the electrochemical properties of SnO2. This effective and innovative strategy could be used for the preparation of perforated metal oxide-CNT composites with complex elemental compositions for many applications. PMID:26355350

  18. Composites for delivery of therapeutics: combining melt electrospun scaffolds with loaded electrosprayed microparticles.

    PubMed

    Bock, Nathalie; Woodruff, Maria A; Steck, Roland; Hutmacher, Dietmar W; Farrugia, Brooke L; Dargaville, Tim R

    2014-02-01

    A novel strategy is reported to produce biodegradable microfiber-scaffolds layered with high densities of microparticles encapsulating a model protein. Direct electrospraying on highly porous melt electrospun scaffolds provides a reproducible scaffold coating throughout the entire architecture. The burst release of protein is significantly reduced due to the immobilization of microparticles on the surface of the scaffold and release mechanisms are dependent on protein-polymer interactions. The composite scaffolds have a positive biological effect in contact with precursor osteoblast cells up to 18 days in culture. The scaffold design achieved with the techniques presented here endorses these new composite scaffolds as promising templates for growth factor delivery. PMID:24106032

  19. Developing bioactive composite scaffolds for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Chen, Yun

    Poly(L-lactic acid) (PLLA) films were fabricated using the method of dissolving and evaporation. PLLA scaffold was prepared by solid-liquid phase separation of polymer solutions and subsequent sublimation of solvent. Bonelike apatite coating was formed on PLLA films, PLLA scaffolds and poly(glycolic acid) (PGA) scaffolds in 24 hours through an accelerated biomimetic process. The ion concentrations in the simulated body fluid (SBF) were nearly 5 times of those in human blood plasma. The apatite formed was characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The apatite formed in 5SBF was similar in morphology and composition to that formed in the classical biomimetic process employing SBF or 1.5SBF, and similar to that of natural bone. This indicated that the biomimetic apatite coating process could be accelerated by using concentrated simulated body fluid at 37°C. Besides saving time, the accelerated biomimetic process is particularly significant to biodegradable polymers. Some polymers which degrade too fast to be coated with apatite by a classical biomimetic process, for example PGA, could be coated with bone-like apatite in an accelerated biomimetic process. Collagen and apatite were co-precipitated as a composite coating on poly(L-lactic acid) (PLLA) in an accelerated biomimetic process. The incubation solution contained collagen (1g/L) and simulated body fluid (SBF) with 5 times inorganic ionic concentrations as human blood plasma. The coating formed on PLLA films and scaffolds after 24 hours incubation was characterized using EDX, XRD, FTIR, and SEM. It was shown that the coating contained carbonated bone-like apatite and collagen, the primary constituents of natural bone. SEM showed a complex composite coating of submicron bone-like apatite particulates combined with collagen fibrils. This work provided an efficient process to obtain

  20. Controllable synthesis of CuS-P(AM-co-MAA) composite microspheres with patterned surface structures.

    PubMed

    Zhang, Ying; Liu, Huijin; Zhao, Ya; Fang, Yu

    2008-09-15

    Copper sulfide-poly(acrylamide-co-methacrylic acid) (CuS-P(AM-co-MAA)) composite microspheres with patterned surface structures have been synthesized in a controllable manner by means of the polymer microgel template method. The formation of CuS particles can be regulated by controlling the decomposition of thioacetamide (TAA) in acidic solution. Compared with the microgel template, the surface morphologies of the composite microspheres are characterized by compact and creased textures. The surface morphology of the composite microspheres has been found to be mainly influenced by the amount of copper sulfide precipitated and hence by the rate of H(2)S gas generation. This study might provide a potential route for controlling the synthesis of various metal sulfide-polymer composites with patterned surface structures. PMID:18649893

  1. Highly Sensitive and Reproducible SERS Performance from Uniform Film Assembled by Magnetic Noble Metal Composite Microspheres.

    PubMed

    Niu, Chunyu; Zou, Bingfang; Wang, Yongqiang; Cheng, Lin; Zheng, Haihong; Zhou, Shaomin

    2016-01-26

    To realize highly sensitive and reproducible SERS performance, a new route was put forward to construct uniform SERS film by using magnetic composite microspheres. In the experiment, monodisperse Fe3O4@SiO2@Ag microspheres with hierarchical surface were developed and used as building block of SERS substrate, which not only realized fast capturing analyte through dispersion and collection under external magnet but also could be built into uniform film through magnetically induced self-assembly. By using R6G as probe molecule, the as-obtained uniform film exhibited great improvement on SERS performance in both sensitivity and reproducibility when compared with nonuniform film, demonstrating the perfect integration of high sensitivity of hierarchal noble metal microspheres and high reproducibility of ordered microspheres array. Furthermore, the as-obtained product was used to detect pesticide thiram and also exhibited excellent SERS performance for trace detection. PMID:26731200

  2. Mechanical properties of hydroxyapatite whisker reinforced polyetherketoneketone composite scaffolds.

    PubMed

    Converse, Gabriel L; Conrad, Timothy L; Roeder, Ryan K

    2009-12-01

    The apparent mechanical properties of hydroxyapatite (HA) whisker reinforced polyetherketoneketone (PEKK) scaffolds were evaluated in unconfined, uniaxial compression to investigate the effects of the porosity (75%, 82.5% and 90%), HA content (0, 20 and 40 vol%) and mold temperature (350, 365 and 375 ( composite function)C). Increased porosity resulted in a non-linear decrease in the elastic modulus and yield strength for both reinforced and unreinforced PEKK scaffolds, as expected. The increase in elastic modulus and yield strength with increased relative density followed a power-law, similar to trabecular bone and other open-cell foams. HA whisker reinforcement generally resulted in an increased elastic modulus from 0 to 20 vol% HA and a subsequent decrease from 20 to 40 vol% HA, while the yield strength and strain were decreased in scaffolds with 40 vol% HA compared to those with 0 or 20 vol% HA. Increased mold temperature resulted in an increased elastic modulus, yield strength and yield strain. These effects enabled the mechanical properties to be tailored to mimic human trabecular bone. The elastic modulus was greater than 50 MPa, and the yield strength was greater than 0.5 MPa, for scaffolds with 75% porosity at all combinations of reinforcement level and mold temperature. Scaffolds with 75% porosity and 20 vol% HA molded at 375 ( composite function)C exhibited a mean elastic modulus and yield strength of 149 MPa and 2.2 MPa, respectively, which was the highest of the conditions investigated in this study and similar to human vertebral trabecular bone. Therefore, HA whisker reinforced PEKK scaffolds may be advantageous for permanent implant fixation, including interbody spinal fusion. PMID:19716108

  3. Preparation and characterization of monodispersed PS/Ag composite microspheres through modified electroless plating

    NASA Astrophysics Data System (ADS)

    Ma, Yuehui; Zhang, Qinghua

    2012-07-01

    A modified electroless silver-plating process has been devised for the preparation of monodispersed, polystyrene/silver (PS/Ag) composite microspheres with tunable shell thickness. Tailoring was achieved by altering the concentration of the silver precursor in the plating bath. PS/Ag composite microspheres were characterized by field-emission scanning electron microscopy, ultraviolet-visible absorption, X-ray diffraction and thermogravimetric analysis. The results showed that a dense, stable and uniform silver nanoshell was formed on the surface of PS microspheres in the presence of poly(vinylpyrrolidone) and glucose. The bulk conductivity of the PS/Ag composites increased from 1.16 S/m to 3.57 × 104 S/m, corresponding to a shell thickness of 35-198 nm. The PS/Ag composite microspheres with diameters of ca. 3 μm might have great potential to be used as fillers in anisotropic conductive films because of the uniform diameter, low density and good conductivity of the microspheres.

  4. Dual-Mode Encoded Magnetic Composite Microsphere Based on Fluorescence Reporters and Raman Probes as Covert Tag for Anticounterfeiting Applications.

    PubMed

    Li, Ruimin; Zhang, Yuting; Tan, Jing; Wan, Jiaxun; Guo, Jia; Wang, Changchun

    2016-04-13

    Utilizing fluorescence reporters and SERS probes as the security labels, a series of dual-mode encoded magnetic composite microspheres with micrometer size was designed and prepared for anticounterfeiting applications. At first, the micro-meter-sized melamine formaldehyde microspheres with different fluorescence molecules (FMF) were prepared by precipitation polymerization, and then the magnetite composite microspheres (FMF/MNPs) were fabricated by direct immobilization of magnetic nanoparticles (MNPs) onto the surface of FMF microspheres. After deposition of Ag nanoparticles (Ag-NPs) onto FMF/MNPs microspheres, the SERS probes were absorbed onto the surface of Ag-NPs, and then a protection layer of silica was coated on the composite microspheres by Stöber method. The combination of different fluorescence reporters and SERS probes greatly increased the encoding complexity and volume for high-level anticounterfeiting. The structure of the dual-encoded FMF/MNPs/Ag-NPs/SiO2 composite microspheres was characterized by FESEM, TEM, FLS(fluorescence spectrometer), XRD, VSM, UV-vis and EDS. The embedded magnetic nanoparticles enable the composite microspheres to be quickly isolated from the marked latex paint by magnet at the concentration of as low as 1 ppm, and the covert tag information can be read out even from one composite microsphere. In addition, the covert security information in the marked coating film can be also read out in situ and the existence of the composite microspheres does not influence the visible appearance of the coating film. All the above outstanding properties will make these dual-mode encoded composite microspheres as advanced security tags for next-generation anticounterfeiting applications. PMID:27010437

  5. Porous nano-hydroxyapatite/collagen scaffold containing drug-loaded ADM-PLGA microspheres for bone cancer treatment.

    PubMed

    Rong, Zi-Jie; Yang, Lian-Jun; Cai, Bao-Ta; Zhu, Li-Xin; Cao, Yan-Lin; Wu, Guo-Feng; Zhang, Zan-Jie

    2016-05-01

    To develop adriamycin (ADM)-encapsulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a porous nano-hydroxyapatite/collagen scaffold (ADM-PLGA-NHAC). To provide novel strategies for future treatment of osteosarcoma, the properties of the scaffold, including its in vitro extended-release properties, the inhibition effects of ADM-PLGA-NHAC on the osteosarcoma MG63 cells, and its bone repair capacity, were investigated in vivo and in vitro. The PLGA copolymer was utilized as a drug carrier to deliver ADM-PLGA nanoparticles (ADM-PLGA-NP). Porous nano-hydroxyapatite and collagen were used to materials to produce the porous nano-hydroxyapatite/collagen scaffold (NHAC), into which the ADM-PLGA-NP was loaded. The performance of the drug-carrying scaffold was assessed using multiple techniques, including scanning electron microscopy and in vitro extended release. The antineoplastic activities of scaffold extracts on the human osteosarcoma MG63 cell line were evaluated in vitro using the cell counting kit-8 (CCK8) method and live-dead cell staining. The bone repair ability of the scaffold was assessed based on the establishment of a femoral condyle defect model in rabbits. ADM-PLGA-NHAC and NHAC were implanted into the rat muscle bag for immune response experiments. A tumor-bearing nude mice model was created, and the TUNEL and HE staining results were observed under optical microscopy to evaluate the antineoplastic activity and toxic side effects of the scaffold. The composite scaffold demonstrated extraordinary extended-release properties, and its extracts also exhibited significant inhibition of the growth of osteosarcoma MG63 cells. In the bone repair experiment, no significant difference was observed between ADM-PLGA-NHAC and NHAC by itself. In the immune response experiments, ADM-PLGA-NHAC exhibited remarkable biocompatibility. The in vivo antitumor experiment revealed that the implantation of ADM-PLGA-NHAC in the tumor resulted in a improved antineoplastic

  6. Hollow superparamagnetic PLGA/Fe 3O 4 composite microspheres for lysozyme adsorption

    NASA Astrophysics Data System (ADS)

    Yang, Qi; Wu, Yao; Lan, Fang; Ma, Shaohua; Xie, Liqin; He, Bin; Gu, Zhongwei

    2014-02-01

    Uniform hollow superparamagnetic poly(lactic-co-glycolic acid) (PLGA)/Fe3O4 composite microspheres composed of an inner cavity, PLGA inner shell and Fe3O4 outer shell have been synthesized by a modified oil-in-water (O/W) emulsion-solvent evaporation method using Fe3O4 nanoparticles as a particulate emulsifier. The obtained composite microspheres with an average diameter of 2.5 μm showed excellent monodispersity and stability in aqueous medium, strong magnetic responsiveness, high magnetite content (>68%), high saturation magnetization (58 emu g-1) and high efficiency in lysozyme adsorption.

  7. Hollow superparamagnetic PLGA/Fe3O4 composite microspheres for lysozyme adsorption.

    PubMed

    Yang, Qi; Wu, Yao; Lan, Fang; Ma, Shaohua; Xie, Liqin; He, Bin; Gu, Zhongwei

    2014-02-28

    Uniform hollow superparamagnetic poly(lactic-co-glycolic acid) (PLGA)/Fe(3)O(4) composite microspheres composed of an inner cavity, PLGA inner shell and Fe(3)O(4) outer shell have been synthesized by a modified oil-in-water (O/W) emulsion-solvent evaporation method using Fe(3)O(4) nanoparticles as a particulate emulsifier. The obtained composite microspheres with an average diameter of 2.5 μm showed excellent monodispersity and stability in aqueous medium, strong magnetic responsiveness, high magnetite content (>68%), high saturation magnetization (58 emu g(-1)) and high efficiency in lysozyme adsorption. PMID:24492410

  8. Cobalt oxide hollow microspheres with micro- and nano-scale composite structure: Fabrication and electrochemical performance

    NASA Astrophysics Data System (ADS)

    Tao, Feifei; Gao, Cuiling; Wen, Zhenhai; Wang, Qiang; Li, Jinghong; Xu, Zheng

    2009-05-01

    Co 3O 4 hollow microspheres with micro- and nano-scale composite structure self-assembled by nanosheets were successfully fabricated by the template-free wet-chemical approach. This method is simple, facile and effective. The Co 3O 4 hollow microspheres with good purity and homogeneous size were well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform IR (FTIR), thermogravimetric analysis (TGA) and inductively coupled plasma atomic emission spectrometer (ICP). The formation mechanism was deeply studied. The micro- and nano-scale composite structure constructed by the porous nanosheets promotes to improve the electrochemical properties of Co 3O 4 hollow microspheres. The high discharge capacity of 1048 mAh g -1 indicates it to be the potential application in electrode materials of Li-ion battery.

  9. Preparation of silver-poly(acrylamide-co-methacrylic acid) composite microspheres with patterned surface structures.

    PubMed

    Xia, Huiyun; Zhang, Ying; Peng, Junxia; Fang, Yu; Gu, Zhongze

    2006-01-01

    Acrylamide (AM) and methacrylic acid (MAA) copolymer microgels were prepared by a reverse suspension polymerization technique. The microgels were used as templates for the preparation of silver-poly(acrylamide-co-methacrylic acid) [Ag-P(AM-co-MAA)] composite microspheres. The surface structures of the microspheres prepared in this way are characterized by zigzag-like structures. It was found that the composition of the microgels, the nature and dosage of surfactants, the quantity of the metal, and even the reduction methods employed have a significant effect upon the surface structures of the microspheres. X-ray diffraction analysis confirmed that Ag formed during the process is in a crystal state of a face-centered cubic structure. PMID:24058232

  10. Novel Alginate-Chitosan Composite Microspheres for Implant Delivery of Vancomycin and In Vivo Evaluation.

    PubMed

    Mao, Yimin; Zhao, Ming; Ge, Yongbiao; Fan, Jiang

    2016-09-01

    In this study, vancomycin loaded alginate-chitosan composite microspheres were developed by emulsion cross-linking method. The in vitro and vivo characterizations were done to evaluate the feasibility of application. Our experimental results showed that the emulsification cross-linking technique appeared to be a feasible method for the preparation of alginate-chitosan composite microspheres. The microspheres were spherical in shape and the mean particle size and drug loading were 25.3 ± 5.4 μm and 18.5 ± 2.3% respectively. A sustained vancomycin release was realized i.e. the amount of cumulative release increased in a time frame of 24 h to reach an amount i.e. ~68%. The model that fit best for vancomycin released from the microspheres was the Higuchi kinetic model with a correlation coefficient r = 0.9996. In vivo results showed that the application of microspheres not only reduced the toxicity, but also maintained effective drug concentration. In addition, no severe signs of epithelial necrosis and sloughing of epithelial cells were detected in histological studies. PMID:27085301

  11. Poly(3-hydroxybutyrate) multifunctional composite scaffolds for tissue engineering applications.

    PubMed

    Misra, Superb K; Ansari, Tahera I; Valappil, Sabeel P; Mohn, Dirk; Philip, Sheryl E; Stark, Wendelin J; Roy, Ipsita; Knowles, Jonathan C; Salih, Vehid; Boccaccini, Aldo R

    2010-04-01

    Poly(3-hydroxybutyrate) (P(3HB)) foams exhibiting highly interconnected porosity (85% porosity) were prepared using a unique combination of solvent casting and particulate leaching techniques by employing commercially available sugar cubes as porogen. Bioactive glass (BG) particles of 45S5 Bioglass grade were introduced in the scaffold microstructure, both in micrometer ((m-BG), <5 microm) and nanometer ((n-BG), 30 nm) sizes. The in vitro bioactivity of the P(3HB)/BG foams was confirmed within 10 days of immersion in simulated body fluid and the foams showed high level of protein adsorption. The foams interconnected porous microstructure proved to be suitable for MG-63 osteoblast cell attachment and proliferation. The foams implanted in rats as subcutaneous implants resulted in a non-toxic and foreign body response after one week of implantation. In addition to showing bioactivity and biocompatibility, the P(3HB)/BG composite foams also exhibited bactericidal properties, which was tested on the growth of Staphylococcus aureus. An attempt was made at developing multifunctional scaffolds by incorporating, in addition to BG, selected concentrations of Vitamin E or/and carbon nanotubes. P(3HB) scaffolds with multifunctionalities (viz. bactericidal, bioactive, electrically conductive, antioxidative behaviour) were thus produced, which paves the way for next generation of advanced scaffolds for bone tissue engineering. PMID:20045554

  12. Suppression of apoptosis by enhanced protein adsorption on polymer/hydroxyapatite composite scaffolds

    PubMed Central

    Woo, Kyung Mi; Seo, Jihye; Zhang, Ruiyun; Ma, Peter X.

    2007-01-01

    Bone tissue engineering is a promising alternative to bone grafting. Scaffolds play a critical role in tissue engineering. Composite scaffolds made of biodegradable polymers and bone mineral-like inorganic compounds have been reported to be advantageous over plain polymer scaffolds by our group and others. In this study, we compared cellular and molecular events during the early periods of osteoblastic cell culture on poly(l-lactic acid)/hydroxyapatite (PLLA/HAP) composite scaffolds with those on plain PLLA scaffolds, and showed that PLLA/HAP scaffolds improved cell survival over plain PLLA scaffolds. Most cells (MC3T3-E1) on PLLA/HAP scaffolds survived the early culture. In contrast, about 50% of the cells initially adhered to the plain PLLA scaffolds were detached within the first 12 h and showed characteristics of apoptotic cell death, which was confirmed by TUNEL staining and caspase-3 activation. To investigate the mechanisms, we examined the adsorption of serum protein and adhesion molecules to the scaffolds. The PLLA/HAP scaffold adsorbed more than 1.4 times of total serum protein and much greater amounts of serum fibronectin and vitronectin than pure PLLA scaffolds. Similarly, significantly larger amounts of individual adhesion proteins and peptides (fibronectin, vitronectin, RGD, and KRSR) were adsorbed on the PLLA/HAP scaffolds than on the PLLA scaffolds, which resulted in higher cell density on the PLLA/HAP scaffolds. Furthermore, β1 and β3 integrins and phosphorylation of Fak and Akt proteins in the cells on the PLLA/HAP scaffolds were significantly more abundent than those on PLLA scaffolds, which suggest that enhanced adsorption of serum adhesion proteins to PLLA/HAP scaffolds protect the cells from apoptosis possibly through the integrin-Fak-Akt pathway. These results demonstrate that biomimetic composite scaffolds are advantageous for bone tissue engineering. PMID:17320948

  13. Biomimetic and bioactive nanofibrous scaffolds from electrospun composite nanofibers

    PubMed Central

    Zhang, YZ; Su, B; Venugopal, J; Ramakrishna, S; Lim, CT

    2007-01-01

    Electrospinning is an enabling technology that can architecturally (in terms of geometry, morphology or topography) and biochemically fabricate engineered cellular scaffolds that mimic the native extracellular matrix (ECM). This is especially important and forms one of the essential paradigms in the area of tissue engineering. While biomimesis of the physical dimensions of native ECM’s major constituents (eg, collagen) is no longer a fabrication-related challenge in tissue engineering research, conveying bioactivity to electrospun nanofibrous structures will determine the efficiency of utilizing electrospun nanofibers for regenerating biologically functional tissues. This can certainly be achieved through developing composite nanofibers. This article gives a brief overview on the current development and application status of employing electrospun composite nanofibers for constructing biomimetic and bioactive tissue scaffolds. Considering that composites consist of at least two material components and phases, this review details three different configurations of nanofibrous composite structures by using hybridizing basic binary material systems as example. These are components blended composite nanofiber, core-shell structured composite nanofiber, and nanofibrous mingled structure. PMID:18203429

  14. Preparation of metal sulfide-polymer composite microspheres with patterned surface structures.

    PubMed

    Fang, Yu; Bai, Chaoliang; Zhang, Ying

    2004-04-01

    CuS-poly(N-isopropylacrylamide), CuS-poly(N-isopropylacrylamide-co-methacrylic acid), Ag(2)S-poly(N-isopropylacrylamide) and Ag(2)S-poly(N-isopropylacrylamide-co-methacrylic acid) composite microspheres exhibiting complex surface morphologies were prepared by employing the minigel template method. PMID:15045072

  15. Electroactive biomimetic collagen-silver nanowire composite scaffolds

    NASA Astrophysics Data System (ADS)

    Wickham, Abeni; Vagin, Mikhail; Khalaf, Hazem; Bertazzo, Sergio; Hodder, Peter; Dånmark, Staffan; Bengtsson, Torbjörn; Altimiras, Jordi; Aili, Daniel

    2016-07-01

    Electroactive biomaterials are widely explored as bioelectrodes and as scaffolds for neural and cardiac regeneration. Most electrodes and conductive scaffolds for tissue regeneration are based on synthetic materials that have limited biocompatibility and often display large discrepancies in mechanical properties with the surrounding tissue causing problems during tissue integration and regeneration. This work shows the development of a biomimetic nanocomposite material prepared from self-assembled collagen fibrils and silver nanowires (AgNW). Despite consisting of mostly type I collagen fibrils, the homogeneously embedded AgNWs provide these materials with a charge storage capacity of about 2.3 mC cm-2 and a charge injection capacity of 0.3 mC cm-2, which is on par with bioelectrodes used in the clinic. The mechanical properties of the materials are similar to soft tissues with a dynamic elastic modulus within the lower kPa range. The nanocomposites also support proliferation of embryonic cardiomyocytes while inhibiting the growth of both Gram-negative Escherichia coli and Gram-positive Staphylococcus epidermidis. The developed collagen/AgNW composites thus represent a highly attractive bioelectrode and scaffold material for a wide range of biomedical applications.Electroactive biomaterials are widely explored as bioelectrodes and as scaffolds for neural and cardiac regeneration. Most electrodes and conductive scaffolds for tissue regeneration are based on synthetic materials that have limited biocompatibility and often display large discrepancies in mechanical properties with the surrounding tissue causing problems during tissue integration and regeneration. This work shows the development of a biomimetic nanocomposite material prepared from self-assembled collagen fibrils and silver nanowires (AgNW). Despite consisting of mostly type I collagen fibrils, the homogeneously embedded AgNWs provide these materials with a charge storage capacity of about 2.3 mC cm-2

  16. Compositional, microstructural, and vibrational characteristics of synthesized V2O5 microspheres with nanorod formation

    NASA Astrophysics Data System (ADS)

    Dhayal Raj, A.; Suresh Kumar, P.; Yang, Q.; Mangalaraj, D.; Ponpandian, N.; Albert Irudayaraj, A.

    2013-07-01

    Microspheres composed of vanadium pentoxide nanorods have been successfully synthesized using a single step solvothermal method. Field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) analysis were used to characterize the morphology of the nanorod-like structures. The results show that the microspheres have an average diameter of 3.5 μm and that the diameter of the nanorods, of which these microspheres consist, ranges from 150 to 200 nm. Chemical and phase composition of the microspheres was analyzed using X-ray Photoemission Spectroscopy (XPS), X-ray diffraction (XRD), and Selective Area Electron Diffraction (SAED). XRD patterns show that the nanorods are composed of V2O5 phase. The SAED patterns confirm the polycrystalline nature of V2O5 phase in the samples. The XPS spectra indicate that the surface of the microsphere samples consist predominantly of vanadium in its V5+ oxidation state. Vibrational analysis was done using Raman spectroscopy and Fourier transform Infrared spectroscopy and the results further confirm the formation of V2O5 phase.

  17. Improving mechanical and biological properties of macroporous HA scaffolds through composite coatings.

    PubMed

    Zhao, J; Lu, X; Duan, K; Guo, L Y; Zhou, S B; Weng, J

    2009-11-01

    Interconnected porous hydroxyapatite (HA) scaffolds are widely used for bone repair and replacement, owing to their ability to support the adhesion, transfer, proliferation and differentiation of cells. In the present study, the polymer impregnation approach was adopted to produce porous HA scaffolds with three-dimensional (3D) porous structures. These scaffolds have an advantage of highly interconnected porosity (approximately 85%) but a drawback of poor mechanical strength. Therefore, the as-prepared HA scaffolds were lined with composite polymer coatings in order to improve the mechanical properties and retain its good bioactivity and biocompatibility at the same time. The composite coatings were based on poly(D,L-lactide) (PDLLA) polymer solutions, and contained single component or combination of HA, calcium sulfate (CS) and chondroitin sulfate (ChS) powders. The effects of composite coatings on scaffold porosity, microstructure, mechanical property, in vitro mineralizing behavior, and cell attachment of the resultant scaffolds were investigated. The results showed that the scaffolds with composite coatings resulted in significant improvement in both mechanical and biological properties while retaining the 3D interconnected porous structure. The in vitro mineralizing behaviors were mainly related to the compositions of CS and ChS powders in the composite coatings. Excellent cell attachments were observed on the pure HA scaffold as well as the three types of composite scaffolds. These composite scaffolds with improved mechanical properties and bioactivities are promising bone substitutes in tissue engineering fields. PMID:19679453

  18. Cytocompatibility and osteogenesis evaluation of HA/GCPU composite as scaffolds for bone tissue engineering.

    PubMed

    Du, Jingjing; Zou, Qin; Zuo, Yi; Li, Yubao

    2014-01-01

    Porous scaffolds for bone repair were prepared from newly designed segmented aliphatic polyurethane based on glyceride of castor oil and isophorone diisocyanate. To promote the scaffolds' biological and mechanical properties, hydroxyapatite powder was incorporated into the polymer matrix. The scaffold (named as HA/GCPU) with 40 wt% HA had an average pore size of 500 μm and a compressive strength of 4.6 MPa. The in vitro cell culture studies demonstrated that the HA/GCPU scaffold owned good cytocompatibility. The scaffold and cell-seeded scaffold were implanted in defects (Ф3 mm × 3 mm) of femoral condyle of Sprague-Dawley rats, respectively. New bone could extensively form in both the scaffold and cell-seeded scaffold. It indicates that the HA/GCPU composite scaffold has good prospect for bone repair and regeneration. PMID:24657710

  19. Preparation and electromagnetic properties of core/shell polystyrene@polypyrrole@nickel composite microspheres.

    PubMed

    Li, Wenzhe; Qiu, Teng; Wang, Leilei; Ren, Shanshan; Zhang, Jiangru; He, Lifan; Li, Xiaoyu

    2013-02-01

    Through a novel method, we successfully synthesized electromagnetic (EM) functional polystyrene@polypyrrole@nickel (PS@PPy@Ni) composite microspheres. The PS@PPy spheres with well-defined core/shell structure have been synthesized via an in situ chemical oxidative copolymerization of pyrrole (Py) and N-2-carboxyethylpyrrole (PyCOOH) templated by PS microspheres. The reaction was carried out under heterophase conditions using the mixture of ethanol and water as the continuous phase. Tailored by the carboxyl groups on the surface of microspheres, magnetic nickel layer has been steady deposited onto the P(Py-PyCOOH) layer of the microspheres through an activation-electroless plating technology. The fine PS@P(Py-PyCOOH)@Ni core/shell structures could be obtained with the PyCOOH content up to 50 wt % in the P(Py-PyCOOH) layer. Moreover, the as-prepared PS@P(Py-PyCOOH)@Ni composites are ferromagnetic materials and behave as a good electromagnetic (EM) absorption material due to the coating of Ni layer around the PS@P(Py-PyCOOH) spheres. The PS@P(Py-PyCOOH)@Ni composite spheres show the remarkable EM wave absorption property with the maximum reflection loss (around -20.06 dB) at 10.69 GHz. The EM wave absorption can retained lower than -10 dB within a broad frequency range from 9.16 to 13.75 GHz. PMID:23277287

  20. Sodium alginate/Na+-rectorite composite microspheres: preparation, characterization, and dye adsorption.

    PubMed

    Yang, Lianli; Ma, Xiaoyan; Guo, Naini

    2012-10-01

    Sodium alginate/Na(+)-rectorite (SA/Na(+)REC) intercalated nano-composite microspheres were prepared in an inverse suspension system. The effect of the preparation conditions of SA/Na(+)REC composite microspheres on adsorption capacity for Basic Blue 9 was investigated. The structure and morphology were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the optimal condition was that the amount of Na(+)-rectorite was 2wt%, the amount of cross-linker was 0.384% and the amount of the initiator was 8%. SEM showed that it is porous products with spherical particulate surface. XRD showed that intercalation is formed between Na(+)-rectorite and sodium alginate. The adsorption capacity of SA/Na(+)REC was investigated in comparison with Na(+)-rectorite and sodium alginate using different cationic dyes. The SA/Na(+)REC composite microspheres showed the highest adsorption capacity. The reason lies in the existence of intercalated sodium alginate. It could enlarge the pore structure of microspheres, facilitating the penetration of macromolecular dyes. PMID:22840012

  1. Electroactive biomimetic collagen-silver nanowire composite scaffolds.

    PubMed

    Wickham, Abeni; Vagin, Mikhail; Khalaf, Hazem; Bertazzo, Sergio; Hodder, Peter; Dånmark, Staffan; Bengtsson, Torbjörn; Altimiras, Jordi; Aili, Daniel

    2016-08-01

    Electroactive biomaterials are widely explored as bioelectrodes and as scaffolds for neural and cardiac regeneration. Most electrodes and conductive scaffolds for tissue regeneration are based on synthetic materials that have limited biocompatibility and often display large discrepancies in mechanical properties with the surrounding tissue causing problems during tissue integration and regeneration. This work shows the development of a biomimetic nanocomposite material prepared from self-assembled collagen fibrils and silver nanowires (AgNW). Despite consisting of mostly type I collagen fibrils, the homogeneously embedded AgNWs provide these materials with a charge storage capacity of about 2.3 mC cm(-2) and a charge injection capacity of 0.3 mC cm(-2), which is on par with bioelectrodes used in the clinic. The mechanical properties of the materials are similar to soft tissues with a dynamic elastic modulus within the lower kPa range. The nanocomposites also support proliferation of embryonic cardiomyocytes while inhibiting the growth of both Gram-negative Escherichia coli and Gram-positive Staphylococcus epidermidis. The developed collagen/AgNW composites thus represent a highly attractive bioelectrode and scaffold material for a wide range of biomedical applications. PMID:27385421

  2. Stimuli-responsive transformation in carbon nanotube/expanding microsphere-polymer composites.

    PubMed

    Loomis, James; Xu, Peng; Panchapakesan, Balaji

    2013-05-10

    Our work introduces a class of stimuli-responsive expanding polymer composites with the ability to unidirectionally transform their physical dimensions, elastic modulus, density, and electrical resistance. Carbon nanotubes and core-shell acrylic microspheres were dispersed in polydimethylsiloxane, resulting in composites that exhibit a binary set of material properties. Upon thermal or infrared stimuli, the liquid cores encapsulated within the microspheres vaporize, expanding the surrounding shells and stretching the matrix. The microsphere expansion results in visible dimensional changes, regions of reduced polymeric chain mobility, nanotube tensioning, and overall elastic to plastic-like transformation of the composite. Here, we show composite transformations including macroscopic volume expansion (>500%), density reduction (>80%), and elastic modulus increase (>675%). Additionally, conductive nanotubes allow for remote expansion monitoring and exhibit distinct loading-dependent electrical responses. With the ability to pattern regions of tailorable expansion, strength, and electrical resistance into a single polymer skin, these composites present opportunities as structural and electrical building blocks in smart systems. PMID:23574648

  3. Composite scaffolds of mesoporous bioactive glass and polyamide for bone repair.

    PubMed

    Su, Jiacan; Cao, Liehu; Yu, Baoqing; Song, Shaojun; Liu, Xinwei; Wang, Zhiwei; Li, Ming

    2012-01-01

    A bone-implanted porous scaffold of mesoporous bioglass/polyamide composite (m-BPC) was fabricated, and its biological properties were investigated. The results indicate that the m-BPC scaffold contained open and interconnected macropores ranging 400-500 μm, and exhibited a porosity of 76%. The attachment ratio of MG-63 cells on m-BPC was higher than polyamide scaffolds at 4 hours, and the cells with normal phenotype extended well when cultured with m-BPC and polyamide scaffolds. When the m-BPC scaffolds were implanted into bone defects of rabbit thighbone, histological evaluation confirmed that the m-BPC scaffolds exhibited excellent biocompatibility and osteoconductivity, and more effective osteogenesis than the polyamide scaffolds in vivo. The results indicate that the m-BPC scaffolds improved the efficiency of new bone regeneration and, thus, have clinical potential for bone repair. PMID:22679367

  4. Composite scaffolds of mesoporous bioactive glass and polyamide for bone repair

    PubMed Central

    Su, Jiacan; Cao, Liehu; Yu, Baoqing; Song, Shaojun; Liu, Xinwei; Wang, Zhiwei; Li, Ming

    2012-01-01

    A bone-implanted porous scaffold of mesoporous bioglass/polyamide composite (m-BPC) was fabricated, and its biological properties were investigated. The results indicate that the m-BPC scaffold contained open and interconnected macropores ranging 400–500 μm, and exhibited a porosity of 76%. The attachment ratio of MG-63 cells on m-BPC was higher than polyamide scaffolds at 4 hours, and the cells with normal phenotype extended well when cultured with m-BPC and polyamide scaffolds. When the m-BPC scaffolds were implanted into bone defects of rabbit thighbone, histological evaluation confirmed that the m-BPC scaffolds exhibited excellent biocompatibility and osteoconductivity, and more effective osteogenesis than the polyamide scaffolds in vivo. The results indicate that the m-BPC scaffolds improved the efficiency of new bone regeneration and, thus, have clinical potential for bone repair. PMID:22679367

  5. Bioglass®/chitosan-polycaprolactone bilayered composite scaffolds intended for osteochondral tissue engineering.

    PubMed

    Yao, Qingqing; Nooeaid, Patcharakamon; Detsch, Rainer; Roether, Judith A; Dong, Yanming; Goudouri, Ourania-Menti; Schubert, Dirk W; Boccaccini, Aldo R

    2014-12-01

    Polymer-coated 45S5 Bioglass(®) (BG)/chitosan-polycaprolactone (BG/CS-PCL) bilayered composite scaffolds were prepared via foam replication and freeze-drying techniques for application in osteochondral tissue engineering. The CS-PCL coated and uncoated BG scaffolds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The mechanical properties of the coated scaffolds were significantly improved in comparison to uncoated scaffolds. The bioactivity and biodegradation behavior of scaffolds were studied in simulated body fluid (SBF) for up to 28 days. The interface between the BG scaffold and the polymer coating layer was observed by SEM and a suitable interpenetration of the polymer into the scaffold struts was found. The effects of coated and uncoated BG scaffolds on MG-63 osteoblast-like cells were evaluated by cell viability, adhesion and proliferation. PMID:24677705

  6. Fabrication and functionalization of dendritic poly(amidoamine)-immobilized magnetic polymer composite microspheres.

    PubMed

    Liu, Hongbo; Guo, Jia; Jin, Lan; Yang, Wuli; Wang, Changchun

    2008-03-20

    The synthesis of functionalized magnetic polymer microspheres was described by a process involving (1) preparation of the monodisperse magnetic seeds according to a two-step procedure including the preparation of bilayer-oleic acid-coated Fe3O4 nanoparticles followed by soap-free emulsion polymerization with methyl methacrylate (MMA) and divinyl benzene (a cross-linking agent, DVB); (2) seeded emulsion polymerization proceeding under the continuous addition of glycidyl methacrylate (GMA) monomers in the presence of the magnetic PMMA seeds; and (3) chemical modification of the PGMA shells with ethylenediamine (EDA) to yield amino groups. As such, the magnetic poly(MMA-DVB-GMA) microspheres were prepared possessing monodispersity, uniform magnetic properties, and abundant surface amino groups. Then, the dendritic poly(amidoamine) (PAMAM) shells were coated on the magnetic particles on the basis of the Michael addition of methyl acrylate and the amidation of the resulting ester with a large excess of EDA, which could achieve generational growth under such uniform stepwise reactions. For improving the luminescence properties of the composite particles, fluorescein isothiocyanate, which is a popular organic dye, was reacted with the terminal -NH2 groups from the dendritic PAMAM shells, resulting in the formation of multifunctional microspheres with excellent photoluminescence, superparamagnetic, and pH-sensitive properties. In this case, it can be expected that an extension of the functionalization of these microspheres is to immobilize other target molecules onto the PAMAM shells to introduce other desired functions for potential chemical and biological applications. PMID:18281972

  7. Three-dimensional chitosan-nanohydroxyapatite composite scaffolds for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Thein-Han, W. W.; Misra, R. D. K.

    2009-09-01

    We describe the structure of biodegradable chitosan-nanohydroxyapatite (nHA) composites scaffolds and their interaction with pre-osteoblasts for bone tissue engineering. The scaffolds were fabricated via freezing and lyophilization. The nanocomposite scaffolds were characterized by a highly porous structure and pore size of ˜50-125 μm, irrespective of nHA content. The observed significant enhancement in the biological response of pre-osteoblast on nanocomposite scaffolds expressed in terms of cell attachment, proliferation, and widespread morphology in relation to pure chitosan points toward their potential use as scaffold material for bone regeneration.

  8. Hierarchical ZnO-Ag-C composite porous microspheres with superior electrochemical properties as anode materials for lithium ion batteries.

    PubMed

    Xie, Qingshui; Ma, Yating; Zeng, Deqian; Zhang, Xiaoqiang; Wang, Laisen; Yue, Guanghui; Peng, Dong-Liang

    2014-11-26

    Hierarchical ZnO-Ag-C composite porous microspheres are successfully synthesized by calcination of the preproduced zinc-silver citrate porous microspheres in argon. The carbon derives from the in situ carbonization of carboxylic acid groups in zinc-silver citrate during annealing treatment. The average particle size of ZnO-Ag-C composite porous microspheres is approximate 1.5 μm. When adopted as the electrode materials in lithium ion batteries, the obtained composite porous microspheres display high specific capacity, excellent cyclability, and good rate capability. A discharge capacity as high as 729 mA h g(-1) can be retained after 200 cycles at 100 mA g(-1). The excellent electrochemical properties of ZnO-Ag-C are ascribed to its unique hierarchical porous configuration as well as the modification of silver and carbon. PMID:25350718

  9. Nano-hydroxyapatite/poly epsilon-caprolactone composite 3D scaffolds for mastoid obliteration

    NASA Astrophysics Data System (ADS)

    Kim, S. E.; Yun, H. S.; Hyun, Y. T.; Shin, J. W.; Song, J. J.

    2009-05-01

    The aim of this study is to evaluate the use of our nano-HA/PCL composite 3D scaffolds as graft materials for mastoid cavity obliteration in an animal model. Nano-HA particles were synthesized by chemical precipitation technique and mixed them with PCL solution to make composite paste. 3D scaffolds were fabricated by a paste extruding deposition process. The nano-HA/PCL 3D scaffolds showed good in vivo bone regeneration behaviour in a rabbit model after 4 and 8 week implantation. To characterize the 3D scaffolds as a grafting material for mastoid obliteration, mastoid cavities were introduced in rats and implanted the scaffolds. After two week implantation, histological examination showed good tissue ingrowth and new bone formation behaviour. It can be argued that our nano-HA/PCL composite 3D scaffold is a promising alternative material for mastoid obliteration.

  10. A biomimetic three-dimensional woven composite scaffold for functional tissue engineering of cartilage

    NASA Astrophysics Data System (ADS)

    Moutos, Franklin T.; Freed, Lisa E.; Guilak, Farshid

    2007-02-01

    Tissue engineering seeks to repair or regenerate tissues through combinations of implanted cells, biomaterial scaffolds and biologically active molecules. The rapid restoration of tissue biomechanical function remains an important challenge, emphasizing the need to replicate structural and mechanical properties using novel scaffold designs. Here we present a microscale 3D weaving technique to generate anisotropic 3D woven structures as the basis for novel composite scaffolds that are consolidated with a chondrocyte-hydrogel mixture into cartilage tissue constructs. Composite scaffolds show mechanical properties of the same order of magnitude as values for native articular cartilage, as measured by compressive, tensile and shear testing. Moreover, our findings showed that porous composite scaffolds could be engineered with initial properties that reproduce the anisotropy, viscoelasticity and tension-compression nonlinearity of native articular cartilage. Such scaffolds uniquely combine the potential for load-bearing immediately after implantation in vivo with biological support for cell-based tissue regeneration without requiring cultivation in vitro.

  11. Preparation of AgCl-polyacrylamide composite microspheres via combination of a polymer microgel template method and a reverse micelle technique.

    PubMed

    Zhang, Ying; Fang, Yu; Xia, Huiyun; Xie, Yuxia; Wang, Ruifang; Li, Xuejun

    2006-08-01

    A new route was created for the preparation of AgCl-polyacrylamide (AgCl-PAM) composite microspheres with patterned surface structures. The route is a combination of a polymer microgel template method and a reverse micelle technique. The size of the AgCl nanoparticles existing on the surfaces of the composite microspheres and the clearness of the surface patterns of the composite microspheres can be altered by simply adjusting the amount of precipitated AgCl and the rate of the deposition reaction. The route can be also used for the preparation of other water-insoluble salt-polymer composite microspheres, such as BaSO(4)-PAM. It is expected that the composite microspheres with patterned surface structures may not only combine the advantages of polymers and those of inorganic compounds, but also combine the advantages of microspheres in the micrometer size range and those in the nanometer size range. PMID:16678839

  12. Influence of storage temperature and moisture on the performance of microsphere/hydrogel composites.

    PubMed

    Wang, Yan; Burgess, Diane J

    2013-09-15

    The current study involved investigation of the effect of storage temperature and moisture on the performance of poly(lactide-co-glycolide) (PLGA) microsphere/poly(vinyl-alcohol) (PVA) hydrogel composites. Physical aging occurred in composites stored at 25°C due to structural relaxation. The glass transition temperature (Tg) and enthalpy of relaxation of the composites increased leading to a slower cumulative % release. The Tg of composites incubated at 40°C, 75% RH decreased significantly due to the plasticization effect of absorbed water, whereas no change was observed in the Tg of microspheres alone; indicating that the hydrogel component enhanced water absorption. PLGA degradation occurred leading to significantly faster dexamethasone release following incubation at 40°C, 75% RH for 1 month. No significant change was observed in the in vitro release profiles of composites after 6 months storage at 25°C, 60% RH, however, release was accelerated following 12 months storage. Accordingly, exposure of the composites to ambient temperature/moisture during storage, shipping or handling may cause physical aging, plasticization, and degradation and hence, their performance may be affected. The extent to which the performance of the composite is affected by storage temperature and moisture is a net effect of physical aging and moisture induced plasticization/hydrolytic degradation. PMID:23811131

  13. A PLG/HAp composite scaffold for lentivirus delivery

    PubMed Central

    Boehler, RM; Shin, S; Fast, AG; Gower, RM; Shea, LD

    2013-01-01

    Gene delivery from tissue engineering scaffolds provides the opportunity to control the microenvironment by inducing expression of regenerative factors. Hydroxyapatite (HAp) nanoparticles can bind lentivirus, and we investigated the incorporation of HAp into poly(lactide-co-glycolide) (PLG) scaffolds in order to retain lentivirus added to the scaffold. PLG/HAp scaffolds loaded with lentivirus enhanced transgene expression over 10-fold in vitro relative to scaffolds without HAp. Following in vivo implantation, PLG/HAp scaffolds promoted transgene expression for more than 100 days, with the level and duration enhanced relative to control scaffolds with lentivirus/HAp complexes added to PLG scaffolds. The extent of HAp incorporated into the scaffold influenced transgene expression, in part through its impact on porous architecture. Expression in vivo was localized to PLG/HAp scaffolds, with macrophages the primary cell type transduced at day 3, yet transduction of neutrophils and dendritic cells was also observed. At day 21 in PLG/HAp scaffolds, non-immune cells were transduced to a greater extent than immune cells, a trend that was opposite results from PLG scaffolds. Thus, in addition to retaining the virus, PLG/HAp influenced cell infiltration and preferentially transduced non-immune cells. PMID:23602363

  14. In vitro osteogenic induction of human marrow-derived mesenchymal stem cells by PCL fibrous scaffolds containing dexamethazone-loaded chitosan microspheres.

    PubMed

    Omidvar, Noushin; Ganji, Fariba; Eslaminejad, Mohamadreza Baghaban

    2016-07-01

    This research reports the encapsulation of dexamethasone (Dex) within the chitosan microspheres (CSMs) embedded in a fibrous structure of poly(ɛ-caprolactone) (PCL) to provide a platform for osteogenic differentiation of human mesenchymal stem cells (hMSCs). Dex loaded CSMs were prepared by spray drying a mixture of chitosan and Dex. Then, they were electrospun with PCL solution to create a bilayer fibrous scaffold (PCL/CSMs-Dex). The CSMs act as good depots for sustained release of Dex over a period of 14 days, without noticeable burst release. This is mainly attributed to the core-shell structure of the final PCL/CSMs-Dex-matrix, which could prolong the release and eliminate the initial burst. The water contact angle of PCL scaffolds decreased from 141.4 ± 3.8 to 118.4 ± 7.6 in the presence of CSMs. Improved proliferation of hMSCs cultured on PCL/CSMs-Dex scaffolds was also evidenced. Furthermore, osteogenic assays showed an increase in alkaline phosphatase activity and mineral deposits. The expression of bone-specific genes also confirmed the osteogenic differentiation of cells cultured on these Dex-loaded core-shell structures. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1657-1667, 2016. PMID:26916786

  15. Hierarchically biomimetic scaffold of a collagen-mesoporous bioactive glass nanofiber composite for bone tissue engineering.

    PubMed

    Hsu, Fu-Yin; Lu, Meng-Ru; Weng, Ru-Chun; Lin, Hsiu-Mei

    2015-04-01

    Mesoporous bioactive glass nanofibers (MBGNFs) were prepared by a sol-gel/electrospinning technique. Subsequently, a collagen-MBGNF (CM) composite scaffold that simultaneously possessed a macroporous structure and collagen nanofibers was fabricated by a gelation and freeze-drying process. Additionally, immersing the CM scaffold in a simulated body fluid resulted in the formation of bone-like apatite minerals on the surface. The CM scaffold provided a suitable environment for attachment to the cytoskeleton. Based on the measured alkaline phosphatase activity and protein expression levels of osteocalcin and bone sialoprotein, the CM scaffold promoted the differentiation and mineralization of MG63 osteoblast-like cells. In addition, the bone regeneration ability of the CM scaffold was examined using a rat calvarial defect model in vivo. The results revealed that CM is biodegradable and could promote bone regeneration. Therefore, a CM composite scaffold is a potential bone graft for bone tissue engineering applications. PMID:25805665

  16. Ultrasonic preparation of hierarchical graphene-oxide/TiO2 composite microspheres for efficient photocatalytic hydrogen production.

    PubMed

    Gao, Peng; Sun, Darren Delai

    2013-11-01

    Hierarchical graphene oxide (GO)-TiO2 composite microspheres with different GO/TiO2 mass ratios were successfully prepared by mixing GO and TiO2 microspheres under ultrasonic conditions. Ultrasonication helped the GO and TiO2 microsphere to uniformly mix on the microscale. The results showed that the GO-TiO2 composites that were prepared by ultrasonic mixing exhibited significantly higher hydrogen-evolution rates than those that were synthesized by simple mechanical grinding, owing to synergetic effects, including enhanced light absorption and scattering, as well as improved interfacial charge transfer because of the excellent contact between the GO sheets and TiO2 microspheres. In addition, GO-TiO2-3 (3 wt.% GO) showed the highest hydrogen-generation rate (305.6 μmol h(-)), which was about 13 and 3.3-times higher than those of TiO2 microsphere and GO-P25 (with 3 wt.% GO), respectively. Finally, a tentative mechanism for hydrogen production is proposed and supported by photoluminescence and transient photocurrent measurements. This work highlights the potential applications of GO-TiO2 composite microspheres in the field of clean-energy production. PMID:23913441

  17. Microwave-assisted synthesis of porous chitosan-modified montmorillonite-hydroxyapatite composite scaffolds.

    PubMed

    Kar, Sumanta; Kaur, Tejinder; Thirugnanam, A

    2016-01-01

    In this study, a porous chitosan-organically modified montmorillonite-hydroxyapatite (CS-OM-HA) composite scaffold was developed by combining microwave irradiation and gas foaming method. Hydroxyapatite (HA) particles of size ∼ 65 nm were synthesized and characterized by X-ray diffraction (XRD) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The prepared composite scaffolds were characterized using ATR-FTIR, XRD, mercury intrusion porosimeter (MIP) and scanning electron microscopy (SEM) studies. The synergistic effect of HA and OM on the mechanical and in vitro biological properties (swelling, degradation, protein adsorption and bioactivity) of the composite scaffolds were evaluated. Swelling, degradation, mechanical property, bioactivity and protein adsorption studies of CS-OM-HA composite scaffolds have shown desirable results in comparison with the pure CS and CS-OM composite scaffolds. CS-OM-HA composite scaffolds were also found to be non-cytotoxic to MG 63 osteoblast cell lines. From the study, it can be concluded that the novel CS-OM-HA composite scaffold with improved mechanical and in vitro biological properties has wide potential in non-load bearing bone tissue engineering applications. PMID:26505953

  18. In situ preparation and protein delivery of silicate–alginate composite microspheres with core-shell structure

    PubMed Central

    Wu, Chengtie; Fan, Wei; Gelinsky, Michael; Xiao, Yin; Chang, Jiang; Friis, Thor; Cuniberti, Gianaurelio

    2011-01-01

    The efficient loading and sustained release of proteins from bioactive microspheres remain a significant challenge. In this study, we have developed bioactive microspheres which can be loaded with protein and then have a controlled rate of protein release into a surrounding medium. This was achieved by preparing a bioactive microsphere system with core-shell structure, combining a calcium silicate (CS) shell with an alginate (A) core by a one-step in situ method. The result was to improve the microspheres' protein adsorption and release, which yielded a highly bioactive material with potential uses in bone repair applications. The composition and the core-shell structure, as well as the formation mechanism of the obtained CS–A microspheres, were investigated by X-ray diffraction, optical microscopy, scanning electron microscopy, energy dispersive spectrometer dot and line-scanning analysis. The protein loading efficiency reached 75 per cent in CS–A microspheres with a core-shell structure by the in situ method. This is significantly higher than that of pure A or CS–A microspheres prepared by non-in situ method, which lack a core-shell structure. CS–A microspheres with a core-shell structure showed a significant decrease in the burst release of proteins, maintaining sustained release profile in phosphate-buffered saline (PBS) at both pH 7.4 and 4.3, compared with the controls. The protein release from CS–A microspheres is predominantly controlled by a Fickian diffusion mechanism. The CS–A microspheres with a core-shell structure were shown to have improved apatite-mineralization in simulated body fluids compared with the controls, most probably owing to the existence of bioactive CS shell on the surface of the microspheres. Our results indicate that the core-shell structure of CS–A microspheres play an important role in enhancing protein delivery and mineralization, which makes these composite materials promising candidates for application in bone

  19. Comparative study of PCL-HAp and PCL-bioglass composite scaffolds for bone tissue engineering.

    PubMed

    Ródenas-Rochina, Joaquín; Ribelles, José Luis Gómez; Lebourg, Myriam

    2013-05-01

    The aim of this work is to compare the effect of hydroxyapatite (HAp) or bioglass (BG) nanoparticles in a polycaprolactone composite scaffold aimed to bone regeneration. To allow a comparison of the influence of both types of fillers, scaffolds made of PCL or composites containing up to 20 % by weight HAp or BG were obtained. Scaffolds showed acceptable mechanical properties for its use and high interconnected porosity apt for cellular colonization. To study the effect of the different materials on pre-osteoblast cells differentiation, samples with 5 % mineral reinforcement, were cultured for up to 28 days in osteogenic medium. Cells proliferated in all scaffolds. Nevertheless, differentiation levels for the selected markers were higher in pure PCL scaffolds than in the composites; inclusion of bioactive particles showed no positive effects on cell differentiation. In osteogenic culture conditions, the presence of bioactive particles is thus not necessary in order to observe good differentiation. PMID:23417519

  20. Magnetic responsive hydroxyapatite composite scaffolds construction for bone defect reparation

    PubMed Central

    Zeng, Xiao Bo; Hu, Hao; Xie, Li Qin; Lan, Fang; Jiang, Wen; Wu, Yao; Gu, Zhong Wei

    2012-01-01

    Introduction In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. A type of magnetic scaffold composed of magnetic nanoparticles (MNPs) and hydroxyapatite (HA) for bone repair has been developed by our research group. Aim and methods In this study, to investigate the influence of the MNP content (in the scaffolds) on the cell behaviors and the interactions between the magnetic scaffold and the exterior magnetic field, a series of MNP-HA magnetic scaffolds with different MNP contents (from 0.2% to 2%) were fabricated by immersing HA scaffold into MNP colloid. ROS 17/2.8 and MC3T3-E1 cells were cultured on the scaffolds in vitro, with and without an exterior magnetic field, respectively. The cell adhesion, proliferation and differentiation were evaluated via scanning electron microscopy; confocal laser scanning microscopy; and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), alkaline phosphatase, and bone gla protein activity tests. Results The results demonstrated the positive influence of the magnetic scaffolds on cell adhesion, proliferation, and differentiation. Further, a higher amount of MNPs on the magnetic scaffolds led to more significant stimulation. Conclusion The magnetic scaffold can respond to the exterior magnetic field and engender some synergistic effect to intensify the stimulating effect of a magnetic field to the proliferation and differentiation of cells. PMID:22848165

  1. Poly-ε-caprolactone composite scaffolds for bone repair.

    PubMed

    Di Liddo, R; Paganin, P; Lora, S; Dalzoppo, D; Giraudo, C; Miotto, D; Tasso, A; Barbon, S; Artico, M; Bianchi, E; Parnigotto, P P; Conconi, M T; Grandi, C

    2014-12-01

    Synthetic biomaterials combined with cells and osteogenic factors represent a promising approach for the treatment of a number of orthopedic diseases, such as bone trauma and congenital malformations. To guarantee optimal biological properties, bone substitutes are prepared with a 3D structure and porosity grade functional to drive cell migration and proliferation, diffusion of factors, vascularization and cell waste expulsion. In this study, synthetic hydroxyapatite (HA) or rat bone extracellular matrix (BP) were examined in an effort to optimize the mechanical properties and osteogenic activity of poly-ε-caprolactone scaffolds prepared with alginate threads (PCL-AT). Using rabbit bone marrow-derived mesenchymal stem cells (rMSCs), the effects of PCL composite substrates on cell adhesion, growth and osteogenic differentiation were evaluated. Micro-CT analysis and scanning electron microscopy evidenced that porous PCL scaffolds containing HA or BP acquire a trabecular bone-like structure with interconnected pores homogenously distributed and are characterized by a pore diameter of approximately 10 µm (PCL-AT-BP) or ranging from 10 to 100 µm. Although the porosity grade of both PCL-AT-HA and PCL-AT-BP promoted optimal conditions for the cell growth of rMSCs at the early phase, the presence of BP was crucial to prolong the cell viability at the late phase. Moreover, a precocious expression of Runx2 (at 7 days) was observed in PCL-AT-BP in combination with osteogenic soluble factors suggesting that BP controls better than HA the osteogenic maturation process in bone substitutes. PMID:25319350

  2. Influence of clay particles on microfluidic-based preparation of hydrogel composite microsphere

    NASA Astrophysics Data System (ADS)

    Hong, Joung Sook

    2016-05-01

    For the successful fabrication of a hydrogel composite microsphere, this study aimed to investigate the influence of clay particles on microsphere formation in a microfluidic device which has flow focusing and a 4.5:1 contraction channel. A poly alginic acid solution (2.0 wt.%) with clay particles was used as the dispersed phase to generate drops in an oil medium, which then merged with drops of a CaCl2 solution for gelation. Drop generations were observed with different flow rates and particles types. When the flow rate increased, drop generation was enhanced and drop size decreased by the build-up of more favorable hydrodynamic flow conditions to detach the droplets. The addition of a small amount of particles insignificantly changed the drop generation behavior even though it reduced interfacial tension and increased the viscosity of the solution. Instead, clays particles significantly affected hydro-gelation depending on the hydrophobicity of particles, which produced further heterogeneity in the shape and size of microsphere.

  3. Formation of superhydrophobic microspheres of poly(vinylidene fluoride- hexafluoropropylene)/graphene composite via gelation.

    PubMed

    Zhang, Li; Zha, Dao-an; Du, Tingting; Mei, Shilin; Shi, Zujin; Jin, Zhaoxia

    2011-07-19

    We report on the spontaneous formation of superhydrophobic poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)/graphene composite microspheres with uniform size via gelation. When the suspension of PVDF-HFP/graphene (0.25 wt. % with respect to PVDF-HFP) in DMF adsorbs water vapor, it changes to a hybrid gel. A dried porous gel is obtained after solvent exchange and freeze drying. Morphology characterization shows that this hybrid gel is composed of PVDF-HFP/graphene microspheres with a diameter of 8-10 μm. In contrast, PVDF-HFP solution gives rise to a cellular microstructure following the same experimental procedures. We further elucidate the formation mechanism on the basis of the characterization by freeze fracture transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry characterizations. Furthermore, contact angle measurements of water on PVDF-HFP/graphene indicates that the hydrophobic nature of PVDF-HFP combined with the micro/nanoscale hierarchical texture creates a superhydrophobic surface. Such superhydrophobic microspheres may have potential applications as water-repellent catalyst-supporting materials. PMID:21657267

  4. Fabrication and biocompatibility of poly(l-lactic acid) and chitosan composite scaffolds with hierarchical microstructures.

    PubMed

    Lou, Tao; Wang, Xuejun; Yan, Xu; Miao, Yu; Long, Yun-Ze; Yin, Hai-Lei; Sun, Bin; Song, Guojun

    2016-07-01

    The scaffold microstructure is crucial to reconstruct tissue normal functions. In this article, poly(l-lactic acid) and chitosan fiber (PLLA/CTSF) composite scaffolds with hierarchical microstructures both in fiber and pore sizes were successfully fabricated by combining thermal induced phase separation and salt leaching techniques. The composite scaffolds consisted of a nanofibrous PLLA matrix with diameter of 50-500nm, and chitosan fibers with diameter of about 20μm were homogenously distributed in the PLLA matrix as a microsized reinforcer. The composite scaffolds also had high porosity (>94%) and hierarchical pore size, which were consisted of both micropores (50nm-10μm) and macropores (50-300μm). By tailoring the microstructure and chemical composition, the mechanical property, pH buffer and protein adsorption capacity of the composite scaffold were improved significantly compared with those of PLLA scaffold. Cell culture results also revealed that the PLLA/CTSF composite scaffolds supported MG-63 osteoblast proliferation and penetration. PMID:27127062

  5. Sol-gel assisted fabrication of collagen hydrolysate composite scaffold: a novel therapeutic alternative to the traditional collagen scaffold.

    PubMed

    Ramadass, Satiesh Kumar; Perumal, Sathiamurthi; Gopinath, Arun; Nisal, Anuya; Subramanian, Saravanan; Madhan, Balaraman

    2014-09-10

    Collagen is one of the most widely used biomaterial for various biomedical applications. In this Research Article, we present a novel approach of using collagen hydrolysate, smaller fragments of collagen, as an alternative to traditionally used collagen scaffold. Collagen hydrolysate composite scaffold (CHCS) was fabricated with sol-gel transition procedure using tetraethoxysilane as the silica precursor. CHCS exhibits porous morphology with pore sizes varying between 380 and 780 μm. Incorporation of silica conferred CHCS with controlled biodegradation and better water uptake capacity. Notably, 3T3 fibroblast proliferation was seen to be significantly better under CHCS treatment when compared to treatment with collagen scaffold. Additionally, CHCS showed excellent antimicrobial activity against the wound pathogens Staphylococcus aureus, Bacillus subtilis, and Escherichia coli due to the inherited antimicrobial activity of collagen hydrolysate. In vivo wound healing experiments with full thickness excision wounds in rat model demonstrated that wounds treated with CHCS showed accelerated healing when compared to wounds treated with collagen scaffold. These findings indicate that the CHCS scaffold from collagen fragments would be an effective and affordable alternative to the traditionally used collagen structural biomaterials. PMID:25105509

  6. A facile in-situ hydrothermal synthesis of SrTiO3/TiO2 microsphere composite

    NASA Astrophysics Data System (ADS)

    Wang, Hongxing; Zhao, Wei; Zhang, Yubo; Zhang, Shimeng; Wang, Zihao; Zhao, Dan

    2016-06-01

    TiO2 was successfully used as sacrificed template to synthesise SrTiO3/TiO2 microsphere composite via an in-situ hydrothermal process. The diameter of SrTiO3/TiO2 microsphere was about 700 nm with the same size of the template, and all of the microspheres were in good dispersity. The optimized reaction parameters for the phase and morphology of the as-synthesized samples were investigated. The results showed the SrTiO3/TiO2 microsphere can be synthesized at 170 °C when the concentration of sodium hydroxide was 0.1 M. Lower hydrothermal temperature hampered the formation of the SrTiO3/TiO2 composite, the higher alkali concentration, however, will destroy the morphology of products. The formation mechanism of SrTiO3/TiO2 microsphere composite was proposed and the photocatalytic properties of the samples were characterized using methylene blue solution as the pollutant under the UV light irradiation. The results indicated the proper OH- concentration will provide a channel for Sr2+ to react with Ti4+ located in the template and form the SrTiO3/TiO2 composite, and those with micro-scaled spherical morphology exhibited good photocatalytic activities.

  7. Boronic acid-functionalized core-shell-shell magnetic composite microspheres for the selective enrichment of glycoprotein.

    PubMed

    Pan, Miaorong; Sun, Yangfei; Zheng, Jin; Yang, Wuli

    2013-09-11

    In this work, core-shell-shell-structured boronic acid-functionalized magnetic composite microspheres Fe3O4@SiO2@poly (methyl methacrylate-co-4-vinylphenylbornoic acid) (Fe3O4@SiO2@P(MMA-co-VPBA)) with a uniform size and fine morphology were synthesized. Here, Fe3O4 magnetic particles were prepared by a solvothermal reaction, whereas the Fe3O4@SiO2 microspheres with a core-shell structure were obtained by a sol-gel process. 3-(Trimethoxysilyl) propyl methacrylate (MPS)-modified Fe3O4@SiO2 was used as the seed in the emulsion polymerization of MMA and VPBA to form the core-shell-shell-structured magnetic composite microspheres. As the boronic acid groups on the surface of Fe3O4@SiO2@P(MMA-co-VPBA) could form tight yet reversible covalent bonds with the cis-1,2-diols groups of glycoproteins, the magnetic composite microspheres were applied to enrich a standard glycoprotein, horseradish peroxidase (HRP), and the results demonstrated that the composite microspheres have a higher affinity for the glycoproteins in the presence of the nonglycoprotein bovine serum albumin (BSA) over HRP. Additionally, different monomer mole ratios of MMA/VPBA were studied, and the results implied that using MMA as the major monomer could reduce the amount of VPBA with a similar glycoprotein enrichment efficiency but a lower cost. PMID:23924282

  8. Development of porous Ti6Al4V/chitosan sponge composite scaffold for orthopedic applications.

    PubMed

    Guo, Miao; Li, Xiang

    2016-01-01

    A novel composite scaffold consisting of porous Ti6Al4V part filled with chitosan sponge was fabricated using a combination of electron beam melting and freeze-drying. The mechanical properties of porous Ti6Al4V part were examined via compressive test. The ultimate compressive strength was 85.35 ± 8.68 MPa and the compressive modulus was 2.26 ± 0.42 GPa. The microstructure of composite scaffold was characterized using scanning electron microscopy. The chitosan sponge filled in Ti6Al4V part exhibited highly porous and well-interconnected micro-pore architecture. The osteoblastic cells were seeded on scaffolds to test their seeding efficiency and biocompatibility. Significantly higher cell seeding efficiency was found on composite scaffold. The biological response of osteoblasts on composite scaffolds was superior in terms of improved cell attachment, higher proliferation, and well-spread morphology in relation to porous Ti6Al4V part. These results suggest that the Ti6Al4V/chitosan composite scaffold is potentially useful as a biomedical scaffold for orthopedic applications. PMID:26478418

  9. Controlled Release of Chitosan and Sericin from the Microspheres-Embedded Wound Dressing for the Prolonged Anti-microbial and Wound Healing Efficacy.

    PubMed

    Aramwit, Pornanong; Yamdech, Rungnapha; Ampawong, Sumate

    2016-05-01

    One approach in wound dressing development is to incorporate active molecules or drugs in the dressing. In order to reduce the frequency of dressing changes as well as to prolong wound healing efficacy, wound dressings that can sustain the release of the active molecules should be developed. In our previous work, we developed chitosan/sericin (CH/SS) microspheres that released sericin in a controlled rate. However, the difficulty of applying the microspheres that easily diffuse and quickly degrade onto the wound was its limitations. In this study, we aimed to develop wound dressing materials which are easier to apply and to provide extended release of sericin. Different amounts of CH/SS microspheres were embedded into various compositions of polyvinyl alcohol/gelatin (PVA/G) scaffolds and fabricated using freeze-drying and glutaraldehyde crosslinking techniques. The obtained CH/SS microspheres-embedded scaffolds with appropriate design and formulation were introduced as a wound dressing material. Sericin was released from the microspheres and the scaffolds in a sustained manner. Furthermore, an optimized formation of the microspheres-embedded scaffolds (2PVA2G+2CHSS) was shown to possess an effective antimicrobial activity against both gram-positive and gram-negative bacteria. These microspheres-embedded scaffolds were not toxic to L929 mouse fibroblast cells, and they did not irritate the tissue when applied to the wound. Finally, probably by the sustained release of sericin, these microspheres-embedded scaffolds could promote wound healing as well as or slightly better than a clinically used wound dressing (Allevyn®) in a mouse model. The antimicrobial CH/SS microspheres-embedded PVA/G scaffolds with sustained release of sericin would appear to be a promising candidate for wound dressing application. PMID:26935427

  10. Facile preparation of well-dispersed CeO2-ZnO composite hollow microspheres with enhanced catalytic activity for CO oxidation.

    PubMed

    Xie, Qingshui; Zhao, Yue; Guo, Huizhang; Lu, Aolin; Zhang, Xiangxin; Wang, Laisen; Chen, Ming-Shu; Peng, Dong-Liang

    2014-01-01

    In this article, well-dispersed CeO2-ZnO composite hollow microspheres have been fabricated through a simple chemical reaction followed by annealing treatment. Amorphous zinc-cerium citrate hollow microspheres were first synthesized by dispersing zinc citrate hollow microspheres into cerium nitrate solution and then aging at room temperature for 1 h. By calcining the as-produced zinc-cerium citrate hollow microspheres at 500 °C for 2 h, CeO2-ZnO composite hollow microspheres with homogeneous composition distribution could be harvested for the first time. The resulting CeO2-ZnO composite hollow microspheres exhibit enhanced activity for CO oxidation compared with CeO2 and ZnO, which is due to well-dispersed small CeO2 particles on the surface of ZnO hollow microspheres and strong interaction between CeO2 and ZnO. Moreover, when Au nanoparticles are deposited on the surface of the CeO2-ZnO composite hollow microspheres, the full CO conversion temperature of the as-produced 1.0 wt % Au-CeO2-ZnO composites reduces from 300 to 60 °C in comparison with CeO2-ZnO composites. The significantly improved catalytic activity may be ascribed to the strong synergistic interplay between Au nanoparticles and CeO2-ZnO composites. PMID:24303982

  11. Collagen/chitosan porous bone tissue engineering composite scaffold incorporated with Ginseng compound K.

    PubMed

    Muthukumar, Thangavelu; Aravinthan, Adithan; Sharmila, Judith; Kim, Nam Soo; Kim, Jong-Hoon

    2016-11-01

    In this study, suitable scaffold materials for bone tissue engineering were successfully prepared using fish scale collagen, hydroxyapatite, chitosan, and beta-tricalcium phosphate. Porous composite scaffolds were prepared by freeze drying method. The Korean traditional medicinal ginseng compound K, a therapeutic agent for the treatment of osteoporosis that reduces inflammation and enhances production of bone morphogenetic protein-2, was incorporated into the composite scaffold. The scaffold was characterized for pore size, swelling, density, degradation, mineralization, cell viability and attachment, and its morphological features were examined using scanning electron microscopy. This characterization and in vitro analysis showed that the prepared scaffold was biocompatible and supported the growth of MG-63 cells, and therefore has potential as an alternative approach for bone regeneration. PMID:27516305

  12. Polycaprolactone-laponite composite scaffold releasing strontium ranelate for bone tissue engineering applications.

    PubMed

    Nair, Bindu P; Sindhu, Megha; Nair, Prabha D

    2016-07-01

    We report polycaprolactone-laponite composite scaffold for the controlled release of strontium ranelate (SRA), a drug for osteoporosis. Laponite-SRA complex with electrostatic interaction between the drug and laponite was obtained through an aqueous phase reaction. Structural evaluation verified complexation of the bulky SRA molecules with the negatively charged laponite tactoid surfaces, leading to extended ordering of the tactoids, leaving behind the interlayer spacing of the laponite unchanged. The laponite-SRA complex was solution blended with polycaprolactone to obtain composite scaffolds. The strategy was found improving the dispersibility of laponite in PCL due to partial organomodification imparted through interaction with the SRA. The composite scaffolds with varying laponite-SRA complex content of 3-12wt% were evaluated in vitro using human osteosarcoma cells. It was confirmed that an optimum composition of the scaffold with 3wt% laponite-SRA complex loading would be ideal for obtaining enhanced ALP activity, by maintaining cell viability. PMID:27037779

  13. Chitin and carbon nanotube composites as biocompatible scaffolds for neuron growth

    NASA Astrophysics Data System (ADS)

    Singh, Nandita; Chen, Jinhu; Koziol, Krzysztof K.; Hallam, Keith R.; Janas, Dawid; Patil, Avinash J.; Strachan, Ally; G. Hanley, Jonathan; Rahatekar, Sameer S.

    2016-04-01

    The design of biocompatible implants for neuron repair/regeneration ideally requires high cell adhesion as well as good electrical conductivity. Here, we have shown that plasma-treated chitin carbon nanotube composite scaffolds show very good neuron adhesion as well as support of synaptic function of neurons. The addition of carbon nanotubes to a chitin biopolymer improved the electrical conductivity and the assisted oxygen plasma treatment introduced more oxygen species onto the chitin nanotube scaffold surface. Neuron viability experiments showed excellent neuron attachment onto plasma-treated chitin nanotube composite scaffolds. The support of synaptic function was evident on chitin/nanotube composites, as confirmed by PSD-95 staining. The biocompatible and electrically-conducting chitin nanotube composite scaffold prepared in this study can be used for in vitro tissue engineering of neurons and, potentially, as an implantable electrode for stimulation and repair of neurons.

  14. Novel polystyrene microspheres functionalized by imidazolium and the electrocatalytic activity towards H2O2 of its Prussian blue composite

    NASA Astrophysics Data System (ADS)

    Mao, Hui; Song, Jinling; Zhang, Qian; Liu, Daliang; Gong, Naiqi; Li, Ying; Wu, Qiong; Verpoort, Francis; Song, Xi-Ming

    2013-05-01

    Copolymerization of styrene (St) and 1-vinyl-3-ethylimidazolium bromide (VEIB), novel poly(St-co-VEIB) microspheres were generated. Owing to the presence of imidazolium groups, such microspheres having an average diameter of 125 nm, behave electropositively when dispersed in aqueous solution. Furthermore, due to the presence of imidazolium groups, having a capacity of ion-exchange and weak reducibility on the surface of the PS microspheres, [Fe(CN)6]3- was absorbed on the surface of poly(St-co-VEIB) microspheres, and simultaneously, Fe3+ was reduced to Fe2+. Thus, in situ growth of Prussian blue (PB) nanoparticles could occur on the surface of poly(St-co-VEIB) microspheres without the addition of any other reducing agent. This methodology, utilizing the ion-exchange and weak reducibility properties of the imidazolium groups on the surface of micro-/nanostructures is a novel general method for assembling hierarchical nanostructured materials. Finally, the electrochemical property of the strawberry-like PS/PB composite microspheres was also investigated by applying a glassy carbon electrode. A good repeatability of the cyclic voltammetry responses, having a good linearity and sensitivity, for the electrocatalytic reduction of H2O2 was obtained.

  15. Poly (D,L-lactide)/nano-hydroxyapatite composite scaffolds for bone tissue engineering and biocompatibility evaluation.

    PubMed

    Ren, Jie; Zhao, Peng; Ren, Tianbin; Gu, Shuying; Pan, Kefeng

    2008-03-01

    Biodegradable polymer/bioceramic composite scaffolds can overcome the limitations of conventional ceramic bone substitutes such as brittleness and difficulty in shaping. However, conventional methods for fabricating polymer/bioceramic composite scaffolds often use organic solvents (e.g., the solvent casting and particulate leaching (SC/PL) method), which might be harmful to cells or tissues. In this study, Poly (D,L-lactide)/nano-hydroxyapatite (PDLLA/NHA) composites were prepared by in-situ polymerization, and highly porous scaffolds were fabricated using a novel method, supercritical CO2/salt-leaching method (SC CO2/SL). The materials and scaffolds were investigated by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and gel permeation chromatography (GPC). GPC showed that the molecular weight of composites decreased with increase of NHA content. However, the water absorption and compressive strength increased dramatically. The SEM micrographs showed that the scaffolds with pore size about 250 microm were obtained by controlling parameters of SC CO2/SL. The biocompatibility of PDLLA/NHA porous scaffolds were evaluated in vitro and in vivo. The evaluation on the cytotoxicity were carried out by cell relative growth rate (RGR) method and cell direct contact method. The cytotoxicity of these scaffolds was in grade I according to ISO 10993-1. There was no toxicosis and death cases observed in acute systemic toxicity test. And histological observation of the tissue response (1 and 9 weeks after the implantation) showed that there are still some slight inflammation responses. PMID:17701303

  16. Porous silicon oxide-PLGA composite microspheres for sustained ocular delivery of daunorubicin

    PubMed Central

    Nan, Kaihui; Ma, Feiyan; Hou, Huiyuan; Freeman, William R.; Sailor, Michael J.; Cheng, Lingyun

    2014-01-01

    A water-soluble anthracycline antibiotic drug (daunorubicin, DNR) was loaded into oxidized porous silicon (pSiO2) microparticles and then encapsulated with a layer of polymer (poly lactide-co-glycolide, PLGA) to investigate their synergistic effects in control of DNR release. Similarly fabricated PLGA-DNR microspheres without pSiO2, and pSiO2 microparticles without PLGA were used as control particles. The composite microparticles synthesized by a solid-in-oil-in-water (S/O/W) emulsion method have mean diameters of 52.33±16.37 μm for PLGA-pSiO2_21/40-DNR and the mean diameter of 49.31±8.87 μm for PLGA-pSiO2_6/20-DNR. The mean size, 26.00±8 μm, of PLGA-DNR was significantly smaller, compared with the other two (p<0.0001). Optical microscopy revealed that PLGA-pSiO2-DNR microsphere contained multiple pSiO2 particles. In vitro release experiments determined that control PLGA-DNR microspheres completely released DNR within 38 days and control pSiO2-DNR microparticles (with no PLGA coating) released DNR within 14 days, while the PLGA-pSiO2-DNR microspheres released DNR for 74 days. Temporal release profiles of DNR from PLGA-pSiO2 composite particles indicated that both PLGA and pSiO2 contribute to the sustained release of the payload. The PLGA-pSiO2 composite displayed a more constant rate of DNR release than the pSiO2 control formulation, and it displayed a significantly slower release of DNR than either the PLGA or pSiO2 formulations. We conclude that this system may be useful in managing unwanted ocular proliferation when formulated with anti-proliferation compounds such as DNR. PMID:24793657

  17. The development of collagen-GAG scaffold-membrane composites for tendon tissue engineering.

    PubMed

    Caliari, Steven R; Ramirez, Manuel A; Harley, Brendan A C

    2011-12-01

    Current tissue engineering approaches for tendon defects require improved biomaterials to balance microstructural and mechanical design criteria. Collagen-glycosaminoglycan (CG) scaffolds have shown considerable success as in vivo regenerative templates and in vitro constructs to study cell behavior. While these scaffolds possess many advantageous qualities, their mechanical properties are typically orders of magnitude lower than orthopedic tissues such as tendon. Taking inspiration from mechanically efficient core-shell composites in nature such as plant stems and porcupine quills, we have created core-shell CG composites that display high bioactivity and improved mechanical integrity. These composites feature integration of a low density, anisotropic CG scaffold core with a high density, CG membrane shell. CG membranes were fabricated via an evaporative process that allowed separate tuning of membrane thickness and elastic moduli and were found to be isotropic in-plane. The membranes were then integrated with an anisotropic CG scaffold core via freeze-drying and subsequent crosslinking. Increasing the relative thickness of the CG membrane shell was shown to increase composite tensile elastic modulus by as much as a factor of 36 in a manner consistent with predictions from layered composites theory. CG scaffold-membrane composites were found to support tendon cell viability, proliferation, and metabolic activity in vitro, suggesting they maintain sufficient permeability while demonstrating improved mechanical strength. This work suggests an effective, biomimetic approach for balancing strength and bioactivity requirements of porous scaffolds for tissue engineering. PMID:21880362

  18. Biological evaluation of porous aliphatic polyurethane/hydroxyapatite composite scaffolds for bone tissue engineering.

    PubMed

    Yang, Wanxun; Both, Sanne K; Zuo, Yi; Birgani, Zeinab Tahmasebi; Habibovic, Pamela; Li, Yubao; Jansen, John A; Yang, Fang

    2015-07-01

    Biomaterial scaffolds meant to function as supporting structures to osteogenic cells play a pivotal role in bone tissue engineering. Recently, we synthesized an aliphatic polyurethane (PU) scaffold via a foaming method using non-toxic components. Through this procedure a uniform interconnected porous structure was created. Furthermore, hydroxyapatite (HA) particles were introduced into this process to increase the bioactivity of the PU matrix. To evaluate the biological performances of these PU-based scaffolds, their influence on in vitro cellular behavior and in vivo bone forming capacity of the engineered cell-scaffold constructs was investigated in this study. A simulated body fluid test demonstrated that the incorporation of 40 wt % HA particles significantly promoted the biomineralization ability of the PU scaffolds. Enhanced in vitro proliferation and osteogenic differentiation of the seeded mesenchymal stem cells were also observed on the PU/HA composite. Next, the cell-scaffold constructs were implanted subcutaneously in a nude mice model. After 8 weeks, a considerable amount of vascularized bone tissue with initial marrow stroma development was generated in both PU and PU/HA40 scaffold. In conclusion, the PU/HA composite is a potential scaffold for bone regeneration applications. PMID:25370308

  19. Polyurethane/poly(lactic-co-glycolic) acid composite scaffolds fabricated by thermally induced phase separation.

    PubMed

    Rowlands, A S; Lim, S A; Martin, D; Cooper-White, J J

    2007-04-01

    In this study, we present a novel composite scaffold fabricated using a thermally induced phase separation (TIPS) process from poly(lactic-co-glycolic) (PLGA) and biomedical polyurethane (PU). This processing method has been tuned to allow intimate (molecular) mixing of these two very different polymers, giving rise to a unique morphology that can be manipulated by controlling the phase separation behaviour of an initially homogenous polymer solution. Pure PLGA scaffolds possessed a smooth, directional fibrous sheet-like structure with pore sizes of 0.1-200mum, a porous Young's modulus of 93.5kPa and were relatively brittle to touch. Pure PU scaffolds had an isotropic emulsion-like structure, a porous Young's modulus of 15.7kPa and were much more elastic than the PLGA scaffolds. The composite PLGA/PU scaffold exhibits advantageous morphological, mechanical and cell adhesion and growth supporting properties, when compared with scaffolds fabricated from PLGA or PU alone. This novel method provides a mechanism for the formation of tailored bioactive scaffolds from nominally incompatible polymers, representing a significant step forward in scaffold processing for tissue-engineering applications. PMID:17258315

  20. Clay nanotube-biopolymer composite scaffolds for tissue engineering

    NASA Astrophysics Data System (ADS)

    Naumenko, Ekaterina A.; Guryanov, Ivan D.; Yendluri, Raghuvara; Lvov, Yuri M.; Fakhrullin, Rawil F.

    2016-03-01

    Porous biopolymer hydrogels doped at 3-6 wt% with 50 nm diameter/0.8 μm long natural clay nanotubes were produced without any cross-linkers using the freeze-drying method. The enhancement of mechanical strength (doubled pick load), higher water uptake and thermal properties in chitosan-gelatine-agarose hydrogels doped with halloysite was demonstrated. SEM and AFM imaging has shown the even distribution of nanotubes within the scaffolds. We used enhanced dark-field microscopy to visualise the distribution of halloysite nanotubes in the implantation area. In vitro cell adhesion and proliferation on the nanocomposites occur without changes in viability and cytoskeleton formation. In vivo biocompatibility and biodegradability evaluation in rats has confirmed that the scaffolds promote the formation of novel blood vessels around the implantation sites. The scaffolds show excellent resorption within six weeks after implantation in rats. Neo-vascularization observed in newly formed connective tissue placed near the scaffold allows for the complete restoration of blood flow. These phenomena indicate that the halloysite-doped scaffolds are biocompatible as demonstrated both in vitro and in vivo. The chitosan-gelatine-agarose doped clay nanotube nanocomposite scaffolds fabricated in this work are promising candidates for tissue engineering applications.Porous biopolymer hydrogels doped at 3-6 wt% with 50 nm diameter/0.8 μm long natural clay nanotubes were produced without any cross-linkers using the freeze-drying method. The enhancement of mechanical strength (doubled pick load), higher water uptake and thermal properties in chitosan-gelatine-agarose hydrogels doped with halloysite was demonstrated. SEM and AFM imaging has shown the even distribution of nanotubes within the scaffolds. We used enhanced dark-field microscopy to visualise the distribution of halloysite nanotubes in the implantation area. In vitro cell adhesion and proliferation on the nanocomposites occur

  1. Intervertebral Disk Tissue Engineering Using Biphasic Silk Composite Scaffolds

    PubMed Central

    Park, Sang-Hyug; Gil, Eun Seok; Cho, Hongsik; Mandal, Biman B.; Tien, Lee W.; Min, Byoung-Hyun

    2012-01-01

    Scaffolds composed of synthetic, natural, and hybrid materials have been investigated as options to restore intervertebral disk (IVD) tissue function. These systems fall short of the lamellar features of the native annulus fibrosus (AF) tissue or focus only on the nucleus pulposus (NP) tissue. However, successful regeneration of the entire IVD requires a combination approach to restore functions of both the AF and NP. To address this need, a biphasic biomaterial structure was generated by using silk protein for the AF and fibrin/hyaluronic acid (HA) gels for the NP. Two cell types, porcine AF cells and chondrocytes, were utilized. For the AF tissue, two types of scaffold morphologies, lamellar and porous, were studied with the porous system serving as a control. Toroidal scaffolds formed out of the lamellar, and porous silk materials were used to generate structures with an outer diameter of 8 mm, inner diameter of 3.5 mm, and a height of 3 mm (the interlamellar distance in the lamellar scaffold was 150–250 μm, and the average pore sizes in the porous scaffolds were 100–250 μm). The scaffolds were seeded with porcine AF cells to form AF tissue, whereas porcine chondrocytes were encapsulated in fibrin/HA hydrogels for the NP tissue and embedded in the center of the toroidal disk. Histology, biochemical assays, and gene expression indicated that the lamellar scaffolds supported AF-like tissue over 2 weeks. Porcine chondrocytes formed the NP phenotype within the hydrogel after 4 weeks of culture with the AF tissue that had been previously cultured for 2 weeks, for a total of 6 weeks of cultivation. This biphasic scaffold simulating in combination of both AF and NP tissues was effective in the formation of the total IVD in vitro. PMID:21919790

  2. The Role of Scaffold Architecture and Composition on the Bone Formation by Adipose-Derived Stem Cells

    PubMed Central

    Declercq, Heidi A.; Desmet, Tim; Dubruel, Peter

    2014-01-01

    Scaffold architecture and composition are crucial parameters determining the initial cell spatial distribution and consequently bone tissue formation. Three-dimensional poly-ɛ-caprolactone (PCL) scaffolds with a 0/90° lay-down pattern were plotted and subjected to (1) an oxygen plasma (PCL O) or (2) a postargon plasma modification with gelatin and fibronectin (PCL Fn). These scaffolds with an open pore structure were compared with more compact scaffolds fabricated by conventional processing techniques: oxidized polylactic acid (LA O) and collagen (COL) scaffolds. Human adipose tissue-derived stem cell/scaffold interactions were studied. The study revealed that the biomimetic surface modification of plotted scaffolds did not increase the seeding efficiency. The proliferation and colonization was superior for PCL Fn in comparison with PCL O. The plotted PCL Fn was completely colonized throughout the scaffold, whereas conventional scaffolds only at the edge. Protein-based scaffolds (PCL Fn and COL) enhanced the differentiation, although plotted scaffolds showed a delay in their differentiation compared with compact scaffolds. In conclusion, protein modification of plotted PCL scaffolds enhances uniform tissue formation, but shows a delayed differentiation in comparison with compact scaffolds. The present study demonstrates that biomimetic PCL scaffolds could serve as a guiding template to obtain a uniform bone tissue formation in vivo. PMID:23998529

  3. Degradability, cytocompatibility, and osteogenesis of porous scaffolds of nanobredigite and PCL–PEG–PCL composite

    PubMed Central

    Hou, Jun; Fan, Donghui; Zhao, Lingming; Yu, Baoqin; Su, Jiacan; Wei, Jie; Shin, Jung-Woog

    2016-01-01

    Biocomposite scaffolds were fabricated by incorporation of nanobredigite (n-BD) into the polymer of poly(ε-caprolactone)–poly(ethyleneglycol)–poly(ε-caprolactone) (PCL–PEG–PCL). The results revealed that the addition of n-BD into PCL–PEG–PCL significantly improved water absorption, compressive strength, and degradability of the scaffolds of n-BD/PCL–PEG–PCL composite (n-BPC) compared with PCL–PEG–PCL scaffolds alone. In addition, the proliferation and alkaline phosphatase activity of MG63 cells cultured on n-BPC scaffolds were obviously higher than that cultured on PCL–PEG–PCL scaffolds. Moreover, the results of the histological evaluation from the animal model revealed that the n-BPC scaffolds significantly improved new bone formation compared with the PCL–PEG–PCL scaffolds, indicating good osteogenesis. The n-BPC scaffolds with good biocompatibility could stimulate cell proliferation, differentiation, and bone tissue regeneration and would be an excellent candidate for bone defect repair. PMID:27555774

  4. Tailoring chitosan/collagen scaffolds for tissue engineering: Effect of composition and different crosslinking agents on scaffold properties.

    PubMed

    Martínez, A; Blanco, M D; Davidenko, N; Cameron, R E

    2015-11-01

    Chitosan/collagen (Chit/Col) blends have demonstrated great potential for use in tissue engineering (TE) applications. However, there exists a lack of detailed study on the influence of important design parameters (i.e, component ratio or crosslinking methods) on the essential properties of the scaffolds (morphology, mechanical stiffness, swelling, degradation and cytotoxicity). This work entailed a systematic study of these essential properties of three Chit/Col compositions, covering a wide range of component ratios and using different crosslinking methods. Our results showed the possibility of tailoring these properties by changing component ratios, since different interactions occurred between Chit/Col: samples with Chit-enriched compositions showed a hydrogen-bonding type complex (HC), whereas a self-crosslinking phenomenon was induced in Col-enriched scaffolds. Additionally, material and biological properties of the resultant matrices were further adjusted and tuned by changing crosslinking conditions. In such way, we obtained a wide range of scaffolds whose properties were tailored to meet specific needs of TE applications. PMID:26256388

  5. Bi-layered calcium phosphate cement-based composite scaffold mimicking natural bone structure

    NASA Astrophysics Data System (ADS)

    He, Fupo; Ye, Jiandong

    2013-08-01

    In this study, a core/shell bi-layered calcium phosphate cement (CPC)-based composite scaffold with adjustable compressive strength, which mimicked the structure of natural cortical/cancellous bone, was fabricated. The dense tubular CPC shell was prepared by isostatic pressing CPC powder with a specially designed mould. A porous CPC core with unidirectional lamellar pore structure was fabricated inside the cavity of dense tubular CPC shell by unidirectional freeze casting, followed by infiltration of poly(lactic-co-glycolic acid) and immobilization of collagen. The compressive strength of bi-layered CPC-based composite scaffold can be controlled by varying thickness ratio of dense layer to porous layer. Compared to the scaffold without dense shell, the pore interconnection of bi-layered scaffold was not obviously compromised because of its high unidirectional interconnectivity but poor three dimensional interconnectivity. The in vitro results showed that the rat bone marrow stromal cells attached and proliferated well on the bi-layered CPC-based composite scaffold. This novel bi-layered CPC-based composite scaffold is promising for bone repair.

  6. Large defect-tailored composite scaffolds for in vivo bone regeneration.

    PubMed

    Ronca, Alfredo; Guarino, Vincenzo; Raucci, Maria Grazia; Salamanna, Francesca; Martini, Lucia; Zeppetelli, Stefania; Fini, Milena; Kon, Elisaveta; Filardo, G; Marcacci, Maurilio; Ambrosio, Luigi

    2014-11-01

    The discovery of new strategies to repair large segmental bone defects is currently an open challenge for worldwide clinicians. In the treatment of critical-sized bone defects, an alternative strategy to traditional bone grafting is always more frequently the use of tailor-made scaffolds modelled on the final size and shape of the implant site. Here, poly-ε-caprolactone-based composite scaffolds including poly-L-lactic acid continuous fibres and hyaluronan derivates (i.e. HYAFF11®) have been investigated for the peculiar 3D architecture characterized by interconnected macroporous networks and tunable mechanical properties. Composite scaffolds were immersed in simulated body fluid solution in order to support in vivo tissue in-growth. Scaffolds loaded with autologous cells (bone marrow stromal cells) plus platelet-rich plasma and osteoconductive protein such bone morphogenetic protein-7 were also tested to evaluate eventual enhancement in bone regeneration. The morphological and mechanical properties of poly-L-lactic acid-reinforced composite scaffolds have been studied to identify the optimal scaffold design to match the implant-site requirements of sheep metatarsal defects. Dynamic mechanical tests allowed to underline the viscoelastic response of the scaffold - resulting in elastic moduli from 2.5 to 1.3 MPa, suitable to temporarily support the structural function of damaged bone tissue. In vivo preliminary investigations in a sheep model of metatarsus shaft defect also showed the attitude of the scaffold to promote osteogenesis, preferentially in association with bone marrow stromal cell and platelet-rich plasma, even if the highest amount of mature bone was reached in the case of scaffold loaded with human bone morphogenetic protein-7 released via hydrolytic degradation of HYAFF11® phases in the implant site. PMID:24951457

  7. Migration of Co-cultured Endothelial Cells and Osteoblasts in Composite Hydroxyapatite/Polylactic Acid Scaffolds

    PubMed Central

    SHAH, AMITA R.; SHAH, SARITA R.; OH, SUNHO; ONG, JOO L.; WENKE, JOSEPH C.; AGRAWAL, C. MAULI

    2014-01-01

    Regeneration of bone in large segmental bone defects requires regeneration of both cortical bone and trabecular bone. A scaffold design consisting of a hydroxyapatite (HA) ring surrounding a polylactic acid (PLA) core simulates the structure of bone and provides an environment for indirect and direct co-culture conditions. In this exper iment, human umbilical vein endothelial cells (EC) and normal human primary osteoblasts (OB) were co-cultured to evaluate cell migration and interactions within this biphasic composite scaffold. Both cell types were able to migrate between the different material phases of the scaffold. It was also observed that OB migration increased when they were co-cultured with ECs, whereas EC migration decreased in co-culture. The results show that co-culture of ECs and OBs in this composite biphasic scaffold allows for migration of cells throughout the scaffold and that pre-seeding a scaffold with ECs can increase OB infiltration into desired areas of the scaffold. PMID:21769541

  8. Electrospun composite scaffolds containing poly(octanediol-co-citrate) for cardiac tissue engineering.

    PubMed

    Prabhakaran, Molamma P; Nair, A Sreekumaran; Kai, Dan; Ramakrishna, Seeram

    2012-07-01

    A biocompatible and elastomeric nanofibrous scaffold is electrospun from a blend of poly(1,8-octanediol-co-citrate) [POC] and poly(L-lactic acid) -co-poly-(3-caprolactone) [PLCL] for application as a bioengineered patch for cardiac tissue engineering. The characterization of the scaffolds was carried out by Fourier transform infra red spectroscopy, scanning electron microscopy (SEM), and tensile measurement. The mechanical properties of the scaffolds are studied with regard to the percentage of POC incorporated with PLCL and the results of the study showed that the mechanical property and degradation behavior of the composites can be tuned with respect to the concentration of POC blended with PLCL. The composite scaffolds with POC: PLCL weight ratio of 40:60 [POC/PLCL4060] was found to have a tensile strength of 1.04 ± 0.11 MPa and Young's Modulus of 0.51 ± 0.10 MPa, comparable to the native cardiac tissue. The proliferation of cardiac myoblast cells on the electrospun POC/PLCL scaffolds was found to increase from Days 2 to 8, with the increasing concentration of POC in the composite. The morphology and cytoskeletal observation of the cells also demonstrated the biocompatibility of the POC containing scaffolds. Electrospun POC/PLCL4060 nanofibers are promising elastomeric substrates that might provide the necessary mechanical cues to cardiac muscle cells for regeneration of the heart. PMID:22328272

  9. Preparation and characterization of aloe vera blended collagen-chitosan composite scaffold for tissue engineering applications.

    PubMed

    Jithendra, Panneerselvam; Rajam, Abraham Merlin; Kalaivani, Thambiran; Mandal, Asit Baran; Rose, Chellan

    2013-08-14

    Collagen-Chitosan (COL-CS) scaffolds supplemented with different concentrations (0.1-0.5%) of aloe vera (AV) were prepared and tested in vitro for their possible application in tissue engineering. After studying the microstructure and mechanical properties of all the composite preparations, a 0.2% AV blended COL-CS scaffold was chosen for further studies. Scaffolds were examined by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA) to understand the intermolecular interactions and their influence on the thermal property of the complex composite. Swelling property in phosphate buffered saline (pH 7.4) and in vitro biodegradability by collagenase digestion method were monitored to assess the stability of the scaffold in a physiological medium in a hydrated condition, and to assay its resistance against enzymatic forces. The scanning electron microscope (SEM) image of the scaffold samples showed porous architecture with gradual change in their morphology and reduced tensile properties with increasing aloe vera concentration. The FTIR spectrum revealed the overlap of the AV absorption peak with the absorption peak of COL-CS. The inclusion of AV to COL-CS increased the thermal stability as well as hydrophilicity of the scaffolds. Cell culture studies on the scaffold showed enhanced growth and proliferation of fibroblasts (3T3L1) without exhibiting any toxicity. Also, normal cell morphology and proliferation were observed by fluorescence microscopy and SEM. The rate of cell growth in the presence/absence of aloe vera in the scaffolds was in the order: COL-CS-AV > COL-CS > TCP (tissue culture polystyrene plate). These results suggested that the aloe vera gel-blended COL-CS scaffolds could be a promising candidate for tissue engineering applications. PMID:23838342

  10. Culture & differentiation of mesenchymal stem cell into osteoblast on degradable biomedical composite scaffold: In vitro study

    PubMed Central

    Jain, Krishan G.; Mohanty, Sujata; Ray, Alok R.; Malhotra, Rajesh; Airan, Balram

    2015-01-01

    Background & objectives: There is a significant bone tissue loss in patients from diseases and traumatic injury. The current autograft transplantation gold standard treatment has drawbacks, namely donor site morbidity and limited supply. The field of tissue engineering has emerged with a goal to provide alternative sources for transplantations to bridge this gap between the need and lack of bone graft. The aim of this study was to prepare biocomposite scaffolds based on chitosan (CHT), polycaprolactone (PCL) and hydroxyapatite (HAP) by freeze drying method and to assess the role of scaffolds in spatial organization, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs) in vitro, in order to achieve bone graft substitutes with improved physical-chemical and biological properties. Methods: Pure chitosan (100CHT) and composites (40CHT/HAP, 30CHT/HAP/PCL and 25CHT/HAP/PCL scaffolds containing 40, 30, 25 parts per hundred resin (phr) filler, respectively) in acetic acid were freeze dried and the porous foams were studied for physicochemical and in vitro biological properties. Results: Scanning electron microscope (SEM) images of the scaffolds showed porous microstructure (20-300 μm) with uniform pore distribution in all compositions. Materials were tested under compressive load in wet condition (using phosphate buffered saline at pH 7.4). The in vitro studies showed that all the scaffold compositions supported mesenchymal stem cell attachment, proliferation and differentiation as visible from SEM images, [3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay, alkaline phosphatase (ALP) assay and quantitative reverse transcription (qRT)-PCR. Interpretation & conclusions: Scaffold composition 25CHT/HAP/PCL showed better biomechanical and osteoinductive properties as evident by mechanical test and alkaline phosphatase activity and osteoblast specific gene expression studies. This study suggests that this novel

  11. Effect of different sintering methods on bioactivity and release of proteins from PLGA microspheres.

    PubMed

    Dormer, Nathan H; Gupta, Vineet; Scurto, Aaron M; Berkland, Cory J; Detamore, Michael S

    2013-10-01

    Macromolecule release from poly(d,l-lactide-co-glycolide) (PLGA) microspheres has been well-characterized, and is a popular approach for delivering bioactive signals from tissue-engineered scaffolds. However, the effect of some processing solvents, sterilization, and mineral incorporation (when used in concert) on long-term release and bioactivity has seldom been addressed. Understanding these effects is of significant importance for microsphere-based scaffolds, given that these scaffolds are becoming increasingly more popular, yet growth factor activity following sintering and/or sterilization is heretofore unknown. The current study evaluated the 6-week release of transforming growth factor (TGF)-β3 and bone morphogenetic protein (BMP)-2 from PLGA and PLGA/hydroxyapatite (HAp) microspheres following exposure to ethanol (EtOH), dense phase carbon dioxide (CO2), or ethylene oxide (EtO). EtO was chosen based on its common use in scaffold sterilization, whereas EtOH and CO2 were chosen given their importance in sintering microspheres together to create scaffolds. Release supernatants were then used in an accelerated cell stimulation study with human bone marrow stromal cells (hBMSCs) with monitoring of gene expression for major chondrogenic and osteogenic markers. Results indicated that in microspheres without HAp, EtOH exposure led to the greatest amount of delivery, while those treated with CO2 delivered the least growth factor. In contrast, formulations with HAp released almost half as much protein, regardless of EtOH or CO2 exposure. Notably, EtO exposure was not found to significantly affect the amount of protein released. Cell stimulation studies demonstrated that eluted protein samples performed similarly to positive controls in PLGA-only formulations, and ambiguously in PLGA/HAp composites. In conclusion, the use of EtOH, subcritical CO2, and EtO in microsphere-based scaffolds may have only slight adverse effects, and possibly even desirable effects in some

  12. Phase transitions of macromolecular microsphere composite hydrogels based on the stochastic Cahn–Hilliard equation

    SciTech Connect

    Li, Xiao Ji, Guanghua Zhang, Hui

    2015-02-15

    We use the stochastic Cahn–Hilliard equation to simulate the phase transitions of the macromolecular microsphere composite (MMC) hydrogels under a random disturbance. Based on the Flory–Huggins lattice model and the Boltzmann entropy theorem, we develop a reticular free energy suit for the network structure of MMC hydrogels. Taking the random factor into account, with the time-dependent Ginzburg-Landau (TDGL) mesoscopic simulation method, we set up a stochastic Cahn–Hilliard equation, designated herein as the MMC-TDGL equation. The stochastic term in the equation is constructed appropriately to satisfy the fluctuation-dissipation theorem and is discretized on a spatial grid for the simulation. A semi-implicit difference scheme is adopted to numerically solve the MMC-TDGL equation. Some numerical experiments are performed with different parameters. The results are consistent with the physical phenomenon, which verifies the good simulation of the stochastic term.

  13. Development of Composite Poly(Lactide-co-Glycolide)- Nanodiamond Scaffolds for Bone Cell Growth.

    PubMed

    Brady, Mariea A; Renzing, Andrea; Douglas, Timothy E L; Liu, Qin; Wille, Sebastian; Parizek, Martin; Bacakova, Lucie; Kromka, Alexander; Jarosova, Marketa; Godier, Greetje; Warnkel, Patrick H

    2015-02-01

    There are relatively few nanotechnologies that can produce nanocomposite scaffolds for cell growth. Electrospinning has emerged as the foremost method of producing nanofibrous biomimetic scaffolds for tissue engineering applications. In this study diamond nanoparticles were integrated into a polymer solution to develop a nanocomposite scaffold containing poly(lactide-co-glycolide) (PLGA) loaded with diamond nanoparticles. To investigate the effect of adding diamond nanoparticles to PLGA scaffolds, primary human mesenchymal stem cells (hMSCs) were seeded on the scaffolds. The cytocompatibility results showed that addition of diamond nanoparticles did not impinge upon cell proliferation, nor was there a cytotoxic cellular response after 9 days in culture. Scanning electron microscopy, transmission electron microscopy, atomic force microscopy and confocal microscopy enabled qualitative characterization of the fibres and revealed cell morphology and number. Furthermore, surface roughness was measured to evaluate diamond nanoparticle modifications, and no significant difference was found between the diamond nanocomposite and pure polymer scaffolds. On the other hand, bright spots on phase images performed by atomic force microscopy suggested a higher hardness at certain points on fibers of the PLGA-nanodiamond composites, which was supported by nanoindentation measurements. This study shows that PLGA nanofibers can be reinforced with nanodiamond without adversely affecting cell behaviour, and thus it sets the foundation for future application of these scaffolds in bone tissue engineering. PMID:26353613

  14. Electrospun Polyhydroxybutyrate and Poly(L-lactide-co-ε-caprolactone) Composites as Nanofibrous Scaffolds

    PubMed Central

    Daranarong, Donraporn; Chan, Rodman T. H.; Wanandy, Nico S.; Molloy, Robert; Punyodom, Winita; Foster, L. John R.

    2014-01-01

    Electrospinning can produce nanofibrous scaffolds that mimic the architecture of the extracellular matrix and support cell attachment for tissue engineering applications. In this study, fibrous membranes of polyhydroxybutyrate (PHB) with various loadings of poly(L-lactide-co-ε-caprolactone) (PLCL) were successfully prepared by electrospinning. In comparison to PLCL scaffolds, PLCL blends with PHB exhibited more irregular fibre diameter distributions and higher average fibre diameters but there were no significant differences in pore size. PLCL/PHB scaffolds were more hydrophilic (<120°) with significantly reduced tensile strength (ca. 1 MPa) compared to PLCL scaffolds (150.9 ± 2.8° and 5.8 ± 0.5 MPa). Increasing PLCL loading in PHB/PLCL scaffolds significantly increased the extension at break, (4–6-fold). PLCL/PHB scaffolds supported greater adhesion and proliferation of olfactory ensheathing cells (OECs) than those exhibiting asynchronous growth on culture plates. Mitochondrial activity of cells cultivated on the electrospun blended membranes was enhanced compared to those grown on PLCL and PHB scaffolds (212, 179, and 153%, resp.). Analysis showed that PLCL/PHB nanofibrous membranes promoted cell cycle progression and reduced the onset of necrosis. Thus, electrospun PLCL/PHB composites promoted adhesion and proliferation of OECs when compared to their individual PLCL and PHB components suggesting potential in the repair and engineering of nerve tissue. PMID:24900983

  15. Data for accelerated degradation of calcium phosphate surface-coated polycaprolactone and polycaprolactone/bioactive glass composite scaffolds.

    PubMed

    Poh, Patrina S P; Hutmacher, Dietmar W; Holzapfel, Boris M; Solanki, Anu K; Woodruff, Maria A

    2016-06-01

    Polycaprolactone (PCL)-based composite scaffolds containing 50 wt% of 45S5 bioactive glass (45S5) or strontium-substituted bioactive glass (SrBG) particles were fabricated into scaffolds using melt-extrusion based additive manufacturing technique. Additionally, the PCL scaffolds were surface coated with a layer of calcium phosphate (CaP). For a comparison of the scaffold degradation, the scaffolds were then subjected to in vitro accelerated degradation by immersion in 5 M sodium hydroxide (NaOH) solution for up to 7 days. The scaffold׳s morphology was observed by means of SEM imaging and scaffold mass loss was recorded over the experimental period. PMID:27081669

  16. Data for accelerated degradation of calcium phosphate surface-coated polycaprolactone and polycaprolactone/bioactive glass composite scaffolds

    PubMed Central

    Poh, Patrina S.P.; Hutmacher, Dietmar W.; Holzapfel, Boris M.; Solanki, Anu K.; Woodruff, Maria A.

    2016-01-01

    Polycaprolactone (PCL)-based composite scaffolds containing 50 wt% of 45S5 bioactive glass (45S5) or strontium-substituted bioactive glass (SrBG) particles were fabricated into scaffolds using melt-extrusion based additive manufacturing technique. Additionally, the PCL scaffolds were surface coated with a layer of calcium phosphate (CaP). For a comparison of the scaffold degradation, the scaffolds were then subjected to in vitro accelerated degradation by immersion in 5 M sodium hydroxide (NaOH) solution for up to 7 days. The scaffold׳s morphology was observed by means of SEM imaging and scaffold mass loss was recorded over the experimental period. PMID:27081669

  17. Preparation of uniform rhodamine B-doped SiO{sub 2}/TiO{sub 2} composite microspheres

    SciTech Connect

    Yang Fuyong; Chu Ying . E-mail: chuying@nenu.edu.cn; Huo Lei; Yang Yang; Liu Yang; Liu Jinglin

    2006-02-15

    Uniform rhodamine B (RB)-doped SiO{sub 2}/TiO{sub 2} composite microspheres with catalytic and fluorescent properties were prepared by an easy and economical method in this paper. The composite microspheres were built up with well-dispersed silica particles as the cores, RB as both the doped agent and stabilizer, and the TiO{sub 2} shells were obtained through the hydrolysis of TiCl{sub 4} in water bath. The morphology and structure of the particles were characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The characterization results indicate that composite particles are all in spherical shape and have a narrow size distribution. The composite particles calcined above 500 deg. C reveal clear crystalline reflection peaks of the rutile TiO{sub 2} which exhibits well catalytic property. The photocatalytic experiment was carried out in order to examine the catalytic property of composite microspheres. The fluorescent property of particles was also investigated. Dye-leakage test indicates that RB molecules entrapped in the composite particles by this method are stable inside the particles.

  18. The Potential to Improve Cell Infiltration in Composite Fiber-Aligned Electrospun Scaffolds by the Selective Removal of Sacrificial Fibers

    PubMed Central

    Baker, Brendon M.; Gee, Albert O.; Metter, Robert B.; Nathan, Ashwin S.; Marklein, Ross L.; Burdick, Jason A.; Mauck, Robert L.

    2008-01-01

    Aligned electrospun scaffolds are a promising tool for engineering fibrous musculoskeletal tissues as they reproduce the mechanical anisotropy of these tissues and can direct ordered neo-tissue formation. However, these scaffolds suffer from a slow cellular infiltration rate, likely due in part to their dense fiber packing. We hypothesized that cell ingress could be expedited in scaffolds by increasing porosity, while at the same time preserving overall scaffold anisotropy. To test this hypothesis, poly(ε-caprolactone) (a slow-degrading polyester) and poly(ethylene oxide) (a water-soluble polymer) were co-electrospun from two separate spinnerets to form dual-polymer composite fiber-aligned scaffolds. Adjusting fabrication parameters produced aligned scaffolds with a full range of sacrificial (PEO) fiber contents. Tensile properties of scaffolds were a function of the ratio of PCL to PEO in the composite scaffolds, and were altered in a predictable fashion with removal of the PEO component. When seeded with mesenchymal stem cells (MSCs), increases in the starting sacrificial fraction (and porosity) improved cell infiltration and distribution after three weeks in culture. In pure PCL scaffolds, cells lined the scaffold periphery, while scaffolds containing >50% sacrificial PEO content had cells present throughout the scaffold. These findings indicate that cell infiltration can be expedited in dense fibrous assemblies with the removal of sacrificial fibers. This strategy may enhance in vitro and in vivo formation and maturation of a functional constructs for fibrous tissue engineering. PMID:18313138

  19. Performance of PRP Associated with Porous Chitosan as a Composite Scaffold for Regenerative Medicine

    PubMed Central

    Shimojo, Andréa Arruda Martins; Perez, Amanda Gomes Marcelino; Galdames, Sofia Elisa Moraga; Brissac, Isabela Cambraia de Souza; Santana, Maria Helena Andrade

    2015-01-01

    This study aimed to evaluate the in vitro performance of activated platelet-rich plasma associated with porous sponges of chitosan as a composite scaffold for proliferation and osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells. The sponges were prepared by controlled freezing (−20, −80, or −196°C) and lyophilization of chitosan solutions (1, 2, or 3% w/v). The platelet-rich plasma was obtained from controlled centrifugation of whole blood and activated with calcium and autologous serum. The composite scaffolds were prepared by embedding the sponges with the activated platelet-rich plasma. The results showed the performance of the scaffolds was superior to that of activated platelet-rich plasma alone, in terms of delaying the release of growth factors and increased proliferation of the stem cells. The best preparation conditions of chitosan composite scaffolds that coordinated the physicochemical and mechanical properties and cell proliferation were 3% (w/v) chitosan and a −20°C freezing temperature, while −196°C favored osteogenic differentiation. Although the composite scaffolds are promising for regenerative medicine, the structures require stabilization to prevent the collapse observed after five days. PMID:25821851

  20. Development of novel chitin/nanosilver composite scaffolds for wound dressing applications.

    PubMed

    Madhumathi, K; Sudheesh Kumar, P T; Abhilash, S; Sreeja, V; Tamura, H; Manzoor, K; Nair, S V; Jayakumar, R

    2010-02-01

    Antibiotic resistance of microorganisms is one of the major problems faced in the field of wound care and management resulting in complications like infection and delayed wound healing. Currently a lot of research is focused on developing newer antimicrobials to treat wounds infected with antibiotic resistant microorganisms. Silver has been used as an antimicrobial agent for a long time in the form of metallic silver and silver sulfadiazine ointments. Recently silver nanoparticles have come up as a potent antimicrobial agent and are finding diverse medical applications ranging from silver based dressings to silver coated medical devices. Chitin is a natural biopolymer with properties like biocompatibility and biodegradability. It is widely used as a scaffold for tissue engineering applications. In this work, we developed and characterized novel chitin/nanosilver composite scaffolds for wound healing applications. The antibacterial, blood clotting and cytotoxicity of the prepared composite scaffolds were also studied. These chitin/nanosilver composite scaffolds were found to be bactericidal against S. aureus and E. coli and good blood clotting ability. These results suggested that these chitin/nanosilver composite scaffolds could be used for wound healing applications. PMID:19802687

  1. Bioactive fish collagen/polycaprolactone composite nanofibrous scaffolds fabricated by electrospinning for 3D cell culture.

    PubMed

    Choi, Da Jeong; Choi, Seung Mi; Kang, Hae Yeong; Min, Hye-Jin; Lee, Rira; Ikram, Muhammad; Subhan, Fazli; Jin, Song Wan; Jeong, Young Hun; Kwak, Jong-Young; Yoon, Sik

    2015-07-10

    One of the most challenging objectives of 3D cell culture is the development of scaffolding materials with outstanding biocompatibility and favorable mechanical strength. In this study, we fabricated a novel nanofibrous scaffold composed of fish collagen (FC) and polycaprolactone (PCL) blends by using the electrospinning method. Nanofibrous scaffolds were characterized using a scanning electron microscope (SEM), and it was revealed that the diameter of nanofibers decreased as FC content was increased in the FC/PCL composite nanofibers. The cytocompatibility of the FC/PCL scaffolds was evaluated by SEM, WST-1 assay, confocal microscopy, western blot, and RT-PCR. It was found that the scaffolds not only facilitated the adhesion, spreading, protrusions, and proliferation of thymic epithelial cells (TECs), but also stimulated the expression of genes and proteins involved in cell adhesion and T-cell development. Thus, these results suggest that the FC/PCL composite nanofibrous scaffolds will be a useful model of 3D cell culture for TECs and may have wide applicability in the future for engineering tissues or organs. PMID:25617682

  2. Impact of polymer structure and composition on fully resorbable endovascular scaffold performance

    PubMed Central

    Ferdous, Jahid; Kolachalama, Vijaya B.; Shazly, Tarek

    2014-01-01

    Fully erodible endovascular scaffolds are being increasingly considered for the treatment of obstructive arterial disease owing to their potential to mitigate long-term risks associated with permanent alternatives. While complete scaffold erosion facilitates vessel healing, generation and release of material degradation by-products from candidate materials such as poly-l-lactide (PLLA) may elicit local inflammatory responses that limit implant efficacy. We developed a computational framework to quantify how the compositional and structural parameters of PLLA-based fully erodible endovascular scaffolds affect degradation kinetics, erosion kinetics and the transient accumulation of material by-products within the arterial wall. Parametric studies reveal that, while some material properties have similar effects on these critical processes, others induce qualitatively opposing responses. For example, scaffold degradation is only mildly responsive to changes in either PLLA polydispersity or the initial degree of crystallinity, while the erosion kinetics is comparatively sensitive to crystallinity. Moreover, lactide doping can effectively tune both scaffold degradation and erosion, but a concomitant increase in local byproduct accumulation raises concerns about implant safety. Optimized erodible endovascular scaffolds must precisely balance therapeutic function and biological response over the implant lifetime, where compositional and structural parameters will have differential effects on implant performance. PMID:23261926

  3. Cytotoxicity and antibacterial ability of scaffolds immobilized by polysaccharide/layered silicate composites.

    PubMed

    Xin, Shangjing; Li, Xueyong; Ma, Zhaocheng; Lei, Zhanjun; Zhao, Jiemin; Pan, Siyi; Zhou, Xue; Deng, Hongbing

    2013-02-15

    Chitosan and pectin/organic rectorite (OREC) were initially deposited on the surface of cellulose acetate electrospun nanofibers by a layer-by-layer (LBL) technique to fabricate scaffolds for bacterial inhibition, and the cytotoxicity of the LBL structured scaffolds was also investigated. A couple of opposite charged material, pectin and OREC, were firstly used to fabricate the intercalated composites. The intercalated structure was determined by selected area electron diffraction. Field-emission scanning electron microscope, X-ray diffraction and X-ray photoelectron spectroscopy were applied for the characterization of LBL structured nanofibrous scaffolds. Antibacterial assay results showed that the diameters of the inhibition zone increased from 7.6 to 15.8 mm for Escherichia coli, as well as from 7.4 to 14.2 mm for Staphylococcus aureus. Finally, human epidermal (EP) cells grew well on the LBL films coating. These novel scaffolds could be an ideal candidate for wound dressings and food packaging. PMID:23399232

  4. Composite Scaffold of Poly(Vinyl Alcohol) and Interfacial Polyelectrolyte Complexation Fibers for Controlled Biomolecule Delivery

    PubMed Central

    Cutiongco, Marie Francene A.; Choo, Royden K. T.; Shen, Nathaniel J. X.; Chua, Bryan M. X.; Sju, Ervi; Choo, Amanda W. L.; Le Visage, Catherine; Yim, Evelyn K. F.

    2015-01-01

    Controlled delivery of hydrophilic proteins is an important therapeutic strategy. However, widely used methods for protein delivery suffer from low incorporation efficiency and loss of bioactivity. The versatile interfacial polyelectrolyte complexation (IPC) fibers have the capacity for precise spatiotemporal release and protection of protein, growth factor, and cell bioactivity. Yet its weak mechanical properties limit its application and translation into a viable clinical solution. To overcome this limitation, IPC fibers can be incorporated into polymeric scaffolds such as the biocompatible poly(vinyl alcohol) hydrogel (PVA). Therefore, we explored the use of a composite scaffold of PVA and IPC fibers for controlled biomolecule release. We first observed that the permeability of biomolecules through PVA films were dependent on molecular weight. Next, IPC fibers were incorporated in between layers of PVA to produce PVA–IPC composite scaffolds with different IPC fiber orientation. The composite scaffold demonstrated excellent mechanical properties and efficient biomolecule incorporation. The rate of biomolecule release from PVA–IPC composite grafts exhibited dependence on molecular weight, with lysozyme showing near-linear release for 1 month. Angiogenic factors were also incorporated into the PVA–IPC grafts, as a potential biomedical application of the composite graft. While vascular endothelial growth factor only showed a maximum cumulative release of 3%, the smaller PEGylated-QK peptide showed maximum release of 33%. Notably, the released angiogenic biomolecules induced endothelial cell activity thus indicating retention of bioactivity. We also observed lack of significant macrophage response against PVA–IPC grafts in a rabbit model. Showing permeability, mechanical strength, precise temporal growth factor release, and bioinertness, PVA–IPC fibers composite scaffolds are excellent scaffolds for controlled biomolecule delivery in soft tissue

  5. Gel-limited synthesis of dumbbell-like Fe3O4-Ag composite microspheres and their SERS applications.

    PubMed

    Zhang, Xiaoli; Niu, Chunyu; Wang, Yongqiang; Zhou, Shaomin; Liu, Jin

    2014-11-01

    A novel gel-limited strategy was developed to synthesize dumbbell-like Fe3O4-Ag composite microspheres through a simple one-pot solvothermal method. In such a reaction system, a special precursor solution containing oleic, water, ethanol and silver ions was used and transformed into a bulk gel under heating at the very beginning of the reaction, thus all the subsequent reactions proceeded in the interior of the gel. The gel-limited reactions had two advantages, on the one hand, the magnetic Fe3O4 microspheres were fixed in the gel which avoided them aggregating together, whereas on the other hand, the silver ions stored in the gel could be gradually released and tended to diffuse towards the nearest Fe3O4 microsphere, which favored the generation of a dumbbell-like Fe3O4-Ag structure. From the time-dependent experiments under optimal conditions, the typical growth process of dumbbell-like structures clearly demonstrated that a silver seed first appeared on the surface of a single Fe3O4 microsphere, which then grew bigger slowly and finally formed a dumbbell-like Fe3O4-Ag structure. Moreover, the formation of the gel was found to be strongly affected by the ratio of water and ethanol in the precursor solution, which further influenced the morphologies of the Fe3O4-Ag microspheres. Furthermore, the effect of lattice match between Fe3O4 and Ag on the final products was also proven from the control experiments by using a template with a different surface crystalline structure. When used as SERS substrates, the final dumbbell-like Fe3O4-Ag microspheres show fast magnetic separation and the selective detection of thiram for the surface capped oleic chain during the growth process. PMID:25188029

  6. Porous magnesium/PLGA composite scaffolds for enhanced bone regeneration following tooth extraction.

    PubMed

    Brown, Andrew; Zaky, Samer; Ray, Herbert; Sfeir, Charles

    2015-01-01

    Sixty percent of implant-supported dental prostheses require bone grafting to enhance bone quantity and quality prior to implant placement. We have developed a metallic magnesium particle/PLGA composite scaffold to overcome the limitations of currently used dental bone grafting materials. This is the first report of porous metallic magnesium/PLGA scaffolds synthesized using a solvent casting, salt leaching method. We found that incorporation of varying amounts of magnesium into the PLGA scaffolds increased the compressive strength and modulus, as well as provided a porous structure suitable for cell infiltration, as measured by mercury intrusion porosimetry. Additionally, combining basic-degrading magnesium with acidic-degrading PLGA led to an overall pH buffering effect and long-term release of magnesium over the course of a 10-week degradation assay, as measured with inductively coupled plasma-atomic emission spectroscopy. Using an indirect proliferation assay adapted from ISO 10993:5, it was found that extracts of medium from degrading magnesium/PLGA scaffolds increased bone marrow stromal cell proliferation in vitro, a phenomenon observed by other groups investigating magnesium's impact on cells. Finally, magnesium/PLGA scaffold biocompatibility was assessed in a canine socket preservation model. Micro-computed tomography and histological analysis showed the magnesium/PLGA scaffolds to be safer and more effective at preserving bone height than empty controls. Three-dimensional magnesium/PLGA composite scaffolds show promise for dental socket preservation and also, potentially, orthopedic bone regeneration. These scaffolds could decrease inflammation observed with clinically used PLGA devices, as well as enhance osteogenesis, as observed with previously studied magnesium devices. PMID:25234156

  7. Repair of articular osteochondral defects of the knee joint using a composite lamellar scaffold

    PubMed Central

    Lv, Y. M.; Yu, Q. S.

    2015-01-01

    Objectives The major problem with repair of an articular cartilage injury is the extensive difference in the structure and function of regenerated, compared with normal cartilage. Our work investigates the feasibility of repairing articular osteochondral defects in the canine knee joint using a composite lamellar scaffold of nano-ß-tricalcium phosphate (ß-TCP)/collagen (col) I and II with bone marrow stromal stem cells (BMSCs) and assesses its biological compatibility. Methods The bone–cartilage scaffold was prepared as a laminated composite, using hydroxyapatite nanoparticles (nano-HAP)/collagen I/copolymer of polylactic acid–hydroxyacetic acid as the bony scaffold, and sodium hyaluronate/poly(lactic-co-glycolic acid) as the cartilaginous scaffold. Ten-to 12-month-old hybrid canines were randomly divided into an experimental group and a control group. BMSCs were obtained from the iliac crest of each animal, and only those of the third generation were used in experiments. An articular osteochondral defect was created in the right knee of dogs in both groups. Those in the experimental group were treated by implanting the composites consisting of the lamellar scaffold of ß-TCP/col I/col II/BMSCs. Those in the control group were left untreated. Results After 12 weeks of implantation, defects in the experimental group were filled with white semi-translucent tissue, protruding slightly over the peripheral cartilage surface. After 24 weeks, the defect space in the experimental group was filled with new cartilage tissues, finely integrated into surrounding normal cartilage. The lamellar scaffold of ß-TCP/col I/col II was gradually degraded and absorbed, while new cartilage tissue formed. In the control group, the defects were not repaired. Conclusion This method can be used as a suitable scaffold material for the tissue-engineered repair of articular cartilage defects. Cite this article: Bone Joint Res 2015;4:56–64 PMID:25837672

  8. Synthesis of microsphere silicon carbide/nanoneedle manganese oxide composites and their electrochemical properties as supercapacitors

    NASA Astrophysics Data System (ADS)

    Kim, Myeongjin; Yoo, Youngjae; Kim, Jooheon

    2014-11-01

    Synthesis of microsphere silicon carbide/nanoneedle MnO2 (SiC/N-MnO2) composites for use as high-performance materials in supercapacitors is reported herein. The synthesis procedure involves the initial treatment of silicon carbide (SiC) with hydrogen peroxide to obtain oxygen-containing functional groups to provide anchoring sites for connection of SiC and the MnO2 nanoneedles (N-MnO2). MnO2 nanoneedles are subsequently formed on the SiC surface. The morphology and microstructure of the as-prepared composites are characterized via X-ray diffractometry, field-emission scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The characterizations indicate that MnO2 nanoneedles are homogeneously formed on the SiC surface in the composite. The capacitive properties of the as-prepared SiC/N-MnO2 electrodes are evaluated using cyclic voltammetry, galvanostatic charge/discharge testing, and electrochemical impedance spectroscopy in a three-electrode experimental setup using a 1-M Na2SO4 aqueous solution as the electrolyte. The SiC/N-MnO2(5) electrode, for which the MnO2/SiC feed ratio is 5:1, displays a specific capacitance as high as 273.2 F g-1 at 10 mV s-1.

  9. Direct Compositional Characterization of (U,Th)O2 Powders, Microspheres, and Pellets Using TXRF.

    PubMed

    Dhara, Sangita; Prabhat, Parimal; Misra, N L

    2015-10-20

    A total reflection X-ray fluorescence (TXRF) analysis method for direct compositional characterization of sintered and green (U,Th)O2 samples in different forms (e.g., pellets, powders, and microspheres) without sample dissolution has been developed for the first time. The methodology involves transfer of only a few nanograms of the sample on the TXRF sample support by gently rubbing the samples on supports or taking their tiny uniform slurry in collodion on the sample support, drying them to make thin film, and measuring the TXRF spectra of the specimens thus prepared. This approach minimizes the matrix effects. Uranium determinations from the TXRF spectra of such specimens were made with respect to thorium, considering it as an internal standard. Samples having uranium atom percent (at%) from 0 to 100 in (U,Th)O2 were analyzed for uranium in comparison to thorium. The results showed an average precision of 2.6% (RSD, 2σ, n = 8). The TXRF-determined results deviated from expected values within 5%. The TXRF results were compared with those of biamperometry with good agreement. The lattice parameters of the solid solutions were calculated using their XRD patterns. A good correlation between lattice parameters and TXRF-determined U at% and between TXRF-determined U at% and expected U at%, calculated on the basis of preparation of (U,Th)O2 solid solutions, was obtained. The developed method is capable of analyzing (U,Th)O2 samples directly with almost negligible sample preparation and is well suited for radioactive samples. The present study suggests that this method can be extended for the determination of U,Th and Pu in other nuclear fuel materials (e.g., nitrides, carbides, etc.) in the form of pellets, powders, and microspheres after suitable modifications in sample handling procedure. PMID:26403807

  10. Three dimensional melt-deposition of polycaprolactone/bio-derived hydroxyapatite composite into scaffold for bone repair.

    PubMed

    Jiang, Wenbo; Shi, Jun; Li, Wei; Sun, Kang

    2013-01-01

    In this study, three dimensional (3D) polycaprolactone/bio-derived hydroxyapatite (PCL/BHA) composite scaffolds were fabricated by using a melt-deposition system (MDS) for the applications in bone repair. PCL/BHA composites with BHA contents of 0, 10, 20, and 40% were successfully processed into 3D scaffolds by using MDS, while it was failed to fabricate PCL/BHA scaffold with BHA content of 60%. The scaffolds produced were demonstrated to possess the same structures as the predefined with highly uniform and completely interconnected pores. The compressive modulus and strength of the PCL/BHA scaffold increased from 27 to 56 MPa and from 1.9 to 4.5 MPa, respectively, as BHA content increased from 0 to 40%. The wettability of PCL/BHA composite scaffold was also improved with the increase of BHA content. Moreover, the PCL/BHA scaffolds fabricated by MDS showed satisfactory biocompatibility and were capable of being integrated with the surrounding host bone. This study shows the feasibility of fabricating 3D PCL/BHA composite scaffolds with favorable pore structures, mechanical properties, wettability and biocompatibility by using MDS and supports further research of developing novel PCL/BHA composite scaffolds with MDS for the applications in bone repair. PMID:23565866

  11. Degradation and biocompatibility of porous nano-hydroxyapatite/polyurethane composite scaffold for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Dong, Zhihong; Li, Yubao; Zou, Qin

    2009-04-01

    Porous scaffold containing 30 wt% nano-hydroxyapatite (n-HA) and 70 wt% polyurethane (PU) from castor oil was prepared by a foaming method and investigated by X-ray diffraction (XRD), Fourier transform infrared absorption (FTIR), scanning electron microscopy (SEM) techniques. The results show that n-HA particles disperse homogeneously in the PU matrix. The porous scaffold has not only macropores of 100-800 μm in size but also a lot of micropores on the walls of macropores. The porosity and compressive strength of scaffold are 80% and 271 kPa, respectively. After soaking in simulated body fluid (SBF), hydrolysis and deposition partly occur on the scaffold. The biological evaluation in vitro and in vivo shows that the n-HA/PU scaffold is non-cytotoxic and degradable. The porous structure provides a good microenvironment for cell adherence, growth and proliferation. The n-HA/PU composite scaffold can be satisfied with the basic requirement for tissue engineering, and has the potential to be applied in repair and substitute of human menisci of the knee-joint and articular cartilage.

  12. Bioactivity and bone healing properties of biomimetic porous composite scaffold: in vitro and in vivo studies.

    PubMed

    Veronesi, Francesca; Giavaresi, Gianluca; Guarino, Vincenzo; Raucci, Maria Grazia; Sandri, Monica; Tampieri, Anna; Ambrosio, Luigi; Fini, Milena

    2015-09-01

    Tissue engineering (TE) represents a valid alternative to traditional surgical therapies for the management of bone defects that do not regenerate spontaneously. Scaffolds, one of the most important component of TE strategy, should be biocompatible, bioactive, osteoconductive, and osteoinductive. The aim of this study was to evaluate the biological properties and bone regeneration ability of a porous poly(ɛ-caprolactone) (PCL) scaffold, incorporating MgCO3 -doped hydroxyapatite particles, uncoated (PCL_MgCHA) or coated by apatite-like crystals via biomimetic treatment (PCL_MgCHAB). It was observed that both scaffolds are not cytotoxic and, even if cell viability was similar on both scaffolds, PCL_MgCHAB showed higher alkaline phosphatase and collagen I (COLL I) production at day 7. PCL_MgCHA induced more tumor necrosis factor-α release than PCL_MgCHAB, while osteocalcin was produced less by both scaffolds up to 7 days and no significant differences were observed for transforming growth factor-β synthesis. The percentage of new bone trabeculae growth in wide defects carried out in rabbit femoral distal epiphyses was significantly higher in PCL_MgCHAB in comparison with PCL_MgCHA at 4 weeks and even more at 12 weeks after implantation. This study highlighted the role of a biomimetic composite scaffold in bone regeneration and lays the foundations for its future employment in the clinical practice. PMID:25689266

  13. Relevance of fiber integrated gelatin-nanohydroxyapatite composite scaffold for bone tissue regeneration

    NASA Astrophysics Data System (ADS)

    Halima Shamaz, Bibi; Anitha, A.; Vijayamohan, Manju; Kuttappan, Shruthy; Nair, Shantikumar; Nair, Manitha B.

    2015-10-01

    Porous nanohydroxyapatite (nanoHA) is a promising bone substitute, but it is brittle, which limits its utility for load bearing applications. To address this issue, herein, biodegradable electrospun microfibrous sheets of poly(L-lactic acid)-(PLLA)-polyvinyl alcohol (PVA) were incorporated into a gelatin-nanoHA matrix which was investigated for its mechanical properties, the physical integration of the fibers with the matrix, cell infiltration, osteogenic differentiation and bone regeneration. The inclusion of sacrificial fibers like PVA along with PLLA and leaching resulted in improved cellular infiltration towards the center of the scaffold. Furthermore, the treatment of PLLA fibers with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide enhanced their hydrophilicity, ensuring firm anchorage between the fibers and the gelatin-HA matrix. The incorporation of PLLA microfibers within the gelatin-nanoHA matrix reduced the brittleness of the scaffolds, the effect being proportional to the number of layers of fibrous sheets in the matrix. The proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells was augmented on the fibrous scaffolds in comparison to those scaffolds devoid of fibers. Finally, the scaffold could promote cell infiltration, together with bone regeneration, upon implantation in a rabbit femoral cortical defect within 4 weeks. The bone regeneration potential was significantly higher when compared to commercially available HA (Surgiwear™). Thus, this biomimetic, porous, 3D composite scaffold could be offered as a promising candidate for bone regeneration in orthopedics.

  14. Synthesis of nanofibrous gelatin/silica bioglass composite microspheres using emulsion coupled with thermally induced phase separation.

    PubMed

    Noh, Da-Young; An, Young-Hyeon; Jo, In-Hwan; Koh, Young-Hag; Kim, Hyoun-Ee

    2016-05-01

    This study proposes an innovative way of synthesizing porous gelatin/silica bioglass composite microspheres with a nanofibrous structure using emulsion coupled with thermally induced phase separation (TIPS). In particular, a mixture of the solvent (water) and non-solvent (ethanol) was used to induce a unique phase separation of gelatin/silica mixtures (i.e. gelatin/silica hybrid-rich and liquid-rich phases) at -70 °C for the creation of a nanofibrous structure. All the composite microspheres synthesized with silica contents of 10 wt.%, 15 wt.%, and 20 wt.% had well-defined spherical shapes between 124 and 136 μm in size. In addition, they were comprised of nanofibrous gelatin/silica composite walls (several tens of nanometers in thickness), where the sol-gel derived silica bioglass phase was uniformly distributed throughout the gelatin matrix. The in vitro apatite-forming ability and biocompatibility of the nanofibrous gelatin/silica bioglass composite microspheres was significantly enhanced with an increase in silica content, demonstrating their great potential for the promotion of bone tissue regeneration. PMID:26952472

  15. Fabrication and characterization of layered chitosan/silk fibroin/nano-hydroxyapatite scaffolds with designed composition and mechanical properties.

    PubMed

    Zhou, Ting; Wu, Jingjing; Liu, Jiaoyan; Luo, Ying; Wan, Ying

    2015-08-01

    Chitosan/nano-hydroxyapatite (HA) composites were first prepared and then used together with chitosan and silk fibroin (SF) to produce a type of four-layer porous scaffold that is potentially applicable for articular cartilage repair. The bottom layer of the scaffold was built with the chitosan/HA composite and the other three layers of the scaffold were fabricated using chitosan/SF composites in which the content of the chitosan and SF was altered in a mutually reversed trend. The so-produced chitosan/SF/HA scaffolds were further crosslinked using tripolyphosphate to achieve enhanced mechanical properties. Interconnected porous microstructures throughout the scaffolds were constructed using a temperature gradient processing technique, and the resultant scaffolds were endowed with graded pore-sizes and porosities as well as porous interface zones between contiguous layers without visual clefts. The compressive modulus and stress at 10% strain of the scaffolds in wet state showed a gradient-changed trend which partially mimics the compressive mechanical properties of an articular cartilage matrix. Cell culture on some chitosan/SF/HA scaffolds for a period of time of up to 14 d showed that the scaffolds were able to well support the growth and infiltration of cells, suggesting that the presently developed chitosan/SF/HA scaffolds have promising potential for articular cartilage repair. PMID:26225911

  16. Poly(ɛ-caprolactone)/gelatin composite electrospun scaffolds with porous crater-like structures for tissue engineering.

    PubMed

    Hwang, Patrick T J; Murdock, Kyle; Alexander, Grant C; Salaam, Amanee D; Ng, Joshua I; Lim, Dong-Jin; Dean, Derrick; Jun, Ho-Wook

    2016-04-01

    Electrospinning has been widely used to fabricate scaffolds imitating the structure of natural extracellular matrix (ECM). However, conventional electrospinning produces tightly compacted nanofiber layers with only small superficial pores and a lack of bioactivity, which limit the usefulness of electrospinning in biomedical applications. Thus, a porous poly(ε-caprolactone) (PCL)/gelatin composite electrospun scaffold with crater-like structures was developed. Porous crater-like structures were created on the scaffold by a gas foaming/salt leaching process; this unique fiber structure had more large pore areas and higher porosity than the conventional electrospun fiber network. Various ratios of PCL/gelatin (concentration ratios: 100/0, 75/25, and 50/50) composite electrospun scaffolds with and without crater-like structures were characterized by their microstructures, surface chemistry, degradation, mechanical properties, and ability to facilitate cell growth and infiltration. The combination of PCL and gelatin endowed the scaffold with both structural stability of PCL and bioactivity of gelatin. All ratios of scaffolds with crater-like structures showed fairly similar surface chemistry, degradation rates, and mechanical properties to equivalent scaffolds without crater-like structures; however, craterized scaffolds displayed higher human mesenchymal stem cell (hMSC) proliferation and infiltration throughout the scaffolds after 7-day culture. Therefore, these results demonstrated that PCL/gelatin composite electrospun scaffolds with crater-like structures can provide a structurally and biochemically improved three-dimensional ECM-mimicking microenvironment. PMID:26567028

  17. Antibacterial properties of poly (octanediol citrate)/gallium-containing bioglass composite scaffolds.

    PubMed

    Zeimaran, Ehsan; Pourshahrestani, Sara; Djordjevic, Ivan; Pingguan-Murphy, Belinda; Kadri, Nahrizul Adib; Wren, Anthony W; Towler, Mark R

    2016-01-01

    Bioactive glasses may function as antimicrobial delivery systems through the incorporation and subsequent release of therapeutic ions. The aim of this study was to evaluate the antimicrobial properties of a series of composite scaffolds composed of poly(octanediol citrate) with increased loads of a bioactive glass that releases zinc (Zn(2+)) and gallium (Ga(3+)) ions in a controlled manner. The antibacterial activity of these scaffolds was investigated against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The ability of the scaffolds to release ions and the subsequent ingress of these ions into hard tissue was evaluated using a bovine bone model. Scaffolds containing bioactive glass exhibited antibacterial activity and this increased in vitro with higher bioactive glass loads; viable cells decreased to about 20 % for the composite scaffold containing 30 % bioactive glass. The Ga(3+) release rate increased as a function of time and Zn(2+) was shown to incorporate into the surrounding bone. PMID:26676864

  18. Design and characterization of a biodegradable composite scaffold for ligament tissue engineering.

    PubMed

    Hayami, James W S; Surrao, Denver C; Waldman, Stephen D; Amsden, Brian G

    2010-03-15

    Herein we report on the development and characterization of a biodegradable composite scaffold for ligament tissue engineering based on the fundamental morphological features of the native ligament. An aligned fibrous component was used to mimic the fibrous collagen network and a hydrogel component to mimic the proteoglycan-water matrix of the ligament. The composite scaffold was constructed from cell-adherent, base-etched, electrospun poly(epsilon-caprolactone-co-D,L-lactide) (PCLDLLA) fibers embedded in a noncell-adherent photocrosslinked N-methacrylated glycol chitosan (MGC) hydrogel seeded with primary ligament fibroblasts. Base etching improved cellular adhesion to the PCLDLLA material. Cells within the MGC hydrogel remained viable (72 +/- 4%) during the 4-week culture period. Immunohistochemistry staining revealed ligament ECM markers collagen type I, collagen type III, and decorin organizing and accumulating along the PCLDLLA fibers within the composite scaffolds. On the basis of these results, it was determined that the composite scaffold design was a viable alternative to the current approaches used for ligament tissue engineering and merits further study. PMID:19353565

  19. A doxorubicin delivery system: Samarium/mesoporous bioactive glass/alginate composite microspheres.

    PubMed

    Zhang, Ying; Wang, Xiang; Su, Yanli; Chen, Dongya; Zhong, Wenxing

    2016-10-01

    Samarium (Sm) incorporated mesoporous bioactive glasses (MBG) microspheres have been prepared using the method of alginate cross-linking with Ca(2+) ions. The in vitro bioactivities of Sm/MBG/alginate microspheres were studied by immersing in simulated body fluid (SBF) for various periods. The results indicated that the Sm/MBG/alginate microspheres have a faster apatite formation rate on the surface. To investigate their delivery properties further, doxorubicin (DOX) was selected as a model drug. The results showed that the Sm/MBG/alginate microspheres exhibit sustained DOX delivery, and their release mechanism is controlled by Fickian diffusion according the Higuchi model. In addition, the delivery of DOX from Sm/MBG/alginate microspheres can be dominated by changing the doping concentration of Sm and the values of pH microenvironment. These all revealed that this material is a promising candidate for the therapy of bone cancer. PMID:27287115

  20. Effect of Dexamethasone-Loaded Poly(Lactic-Co-Glycolic Acid) Microsphere/Poly(Vinyl Alcohol) Hydrogel Composite Coatings on the Basic Characteristics of Implantable Glucose Sensors

    PubMed Central

    Wang, Yan; Vaddiraju, Santhisagar; Qiang, Liangliang; Xu, Xiaoming; Papadimitrakopoulos, Fotios; Burgess, Diane J.

    2012-01-01

    Background Hydrogels alone and in combination with microsphere drug delivery systems are being considered as biocompatible coatings for implantable glucose biosensors to prevent/minimize the foreign body response. Previously, our group has demonstrated that continuous release of dexamethasone from poly(lactic-co-glycolic acid) (PLGA) microsphere/poly(vinyl alcohol) (PVA) hydrogel composites can successfully prevent foreign body response at the implantation site. The objective of this study was to investigate the effect of this composite coating on sensor functionality. Methods The PLGA microsphere/PVA hydrogel coatings were prepared and applied to glucose biosensors. The swelling properties of the composite coatings and their diffusivity to glucose were evaluated as a function of microsphere loading. Sensor linearity, response time, and sensitivity were also evaluated as a function of coating composition. Results The PLGA microsphere/PVA hydrogel composite coating did not compromise sensor linearity (sensors were linear up to 30 mM), which is well beyond the physiological glucose range (2 to 22 mM). The sensor response time did increase in the presence of the coating (from 10 to 19 s); however, this response time was still less than the average reported values. Although the sensitivity of the sensors decreased from 73 to 62 nA/mM glucose when the PLGA microsphere loading in the PVA hydrogel changed from 0 to 100 mg/ml, this reduced sensitivity is acceptable for sensor functionality. The changes in sensor response time and sensitivity were due to changes in glucose permeability as a result of the coatings. The embedded PLGA microspheres reduced the fraction of bulk water present in the hydrogel matrix and consequently reduced glucose diffusion. Conclusions This study demonstrates that the PLGA microsphere/PVA hydrogel composite coatings allow sufficient glucose diffusion and sensor functionality and therefore may be utilized as a smart coating for implantable

  1. Rapid Prototyping Amphiphilic Polymer/Hydroxyapatite Composite Scaffolds with Hydration-Induced Self-Fixation Behavior

    PubMed Central

    Kutikov, Artem B.; Gurijala, Anvesh

    2015-01-01

    Two major factors hampering the broad use of rapid prototyped biomaterials for tissue engineering applications are the requirement for custom-designed or expensive research-grade three-dimensional (3D) printers and the limited selection of suitable thermoplastic biomaterials exhibiting physical characteristics desired for facile surgical handling and biological properties encouraging tissue integration. Properly designed thermoplastic biodegradable amphiphilic polymers can exhibit hydration-dependent hydrophilicity changes and stiffening behavior, which may be exploited to facilitate the surgical delivery/self-fixation of the scaffold within a physiological tissue environment. Compared to conventional hydrophobic polyesters, they also present significant advantages in blending with hydrophilic osteoconductive minerals with improved interfacial adhesion for bone tissue engineering applications. Here, we demonstrated the excellent blending of biodegradable, amphiphilic poly(D,L-lactic acid)-poly(ethylene glycol)-poly(D,L-lactic acid) (PLA-PEG-PLA) (PELA) triblock co-polymer with hydroxyapatite (HA) and the fabrication of high-quality rapid prototyped 3D macroporous composite scaffolds using an unmodified consumer-grade 3D printer. The rapid prototyped HA-PELA composite scaffolds and the PELA control (without HA) swelled (66% and 44% volume increases, respectively) and stiffened (1.38-fold and 4-fold increases in compressive modulus, respectively) in water. To test the hypothesis that the hydration-induced physical changes can translate into self-fixation properties of the scaffolds within a confined defect, a straightforward in vitro pull-out test was designed to quantify the peak force required to dislodge these scaffolds from a simulated cylindrical defect at dry versus wet states. Consistent with our hypothesis, the peak fixation force measured for the PELA and HA-PELA scaffolds increased 6-fold and 15-fold upon hydration, respectively. Furthermore, we showed that

  2. Preparation of chitosan-graft-polyacrylamide magnetic composite microspheres for enhanced selective removal of mercury ions from water.

    PubMed

    Li, Kun; Wang, Yawen; Huang, Mu; Yan, Han; Yang, Hu; Xiao, Shoujun; Li, Aimin

    2015-10-01

    A novel magnetic composite microsphere based on polyacrylamide (PAM)-grafted chitosan and silica-coated Fe3O4 nanoparticles (CS-PAM-MCM) was successfully synthesized by a simple method. The molecular structure, surface morphology, and magnetic characteristics of the composite microsphere were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), and scanning electron microscopy (SEM). The prepared CS-PAM-MCM was applied as an efficient adsorbent for the removal of copper(II), lead(II), and mercury(II) ions from aqueous solutions in respective single, binary, and ternary metal systems. Compared with chitosan magnetic composite microsphere (CS-MCM) without modification, CS-PAM-MCM showed improved adsorption capacity for each metal ion and highly selective adsorption for Hg from Pb and Cu. This improvement is attributed to the formation of stronger interactions between Hg and the amide groups of PAM branches for chelating effects. The adsorption isotherms of Hg/Cu and Hg/Pb binary metal systems onto CS-PAM-MCM are both well-described by extended and modified Langmuir models, indicating that the removal of the three aforementioned metal ions may follow a similar adsorption manner; that is, through a homogeneous monolayer chemisorption process. Furthermore, these magnetic adsorbents could be easily regenerated in EDTA aqueous solution and reused virtually without any adsorption capacity loss. PMID:26073848

  3. Preparation and characterization of bioactive composite scaffolds from polycaprolactone nanofibers-chitosan-oxidized starch for bone regeneration.

    PubMed

    Nourmohammadi, Jhamak; Ghaee, Azadeh; Liavali, Samira Hosseini

    2016-03-15

    The objective of this study was to fabricate and investigate the characteristics of a suitable scaffold for bone regeneration. Therefore, chitosan was combined with various amounts of oxidized starch through reductive alkylation process. Afterwards, chopped CaP-coated PCL nanofibers were added into the chitosan-starch composite scaffolds in order to obtain bioactivity and mimic bone extracellular matrix structure. Scanning electron microscopy confirmed that all scaffolds had well-interconnected porous structure. The mean pore size, porosity, and water uptake of the composite scaffolds increased by incorporation of higher amounts of starch, while this trend was opposite for compressive modulus and strength. Osteoblast-like cells (MG63) culturing on the scaffolds demonstrated that higher starch content could improve cell viability. Moreover, the cells spread and anchored well on the scaffolds, on which the surface was covered with a monolayer of cells. PMID:26794750

  4. Biodegradable composite scaffolds of bioactive glass/chitosan/carboxymethyl cellulose for hemostatic and bone regeneration.

    PubMed

    Chen, Chen; Li, Hong; Pan, Jianfeng; Yan, Zuoqin; Yao, Zhenjun; Fan, Wenshuai; Guo, Changan

    2015-02-01

    Hemostasis in orthopedic osteotomy or bone cutting requires different methods and materials. The bleeding of bone marrow can be mostly stopped by bone wax. However, the wax cannot be absorbed, which leads to artificial prosthesis loosening, foreign matter reaction, and infection. Here, a bioactive glass/chitosan/carboxymethyl cellulose (BG/CS/CMC) composite scaffold was designed to replace traditional wax. WST-1 assay indicated the BG/CS/CMC composite resulted in excellent biocompatibility with no cytotoxicity. In vivo osteogenesis assessment revealed that the BG/CS/CMC composite played a dominant role in bone regeneration and hemostasis. The BG/CS/CMC composite had the same hemostasis effect as bone wax; in addition its biodegradation also led to the functional reconstruction of bone defects. Thus, BG/CS/CMC scaffolds can serve as a potential material for bone repair and hemostasis in critical-sized bone defects. PMID:25326173

  5. Stem cell differentiation-related protein-loaded PLGA microspheres as a novel platform micro-typed scaffold for chondrogenesis.

    PubMed

    Park, Ji Sun; Lim, Hye-Jin; Yi, Se Won; Park, Keun-Hong

    2016-01-01

    During cell differentiation for tissue regeneration, several factors, including growth factors and proteins, influence cascades in stem cells such as embryonic stem cells and mesenchymal stem cells (MSCs). In this study, transforming growth factor (TGF)-β3 and SOX9, which is an important protein in chondrocytes, were used to generate mature chondrocytes from human MSCs (hMSCs). For safe and effective delivery of bioactive molecules into hMSCs, biodegradable poly-(d,l-lactide-co-glycolide) (PLGA) microspheres (MSs) were coated with TGF-β3 and loaded with SOX9. Instead of SOX9 protein, release of the model protein FITC-bovine serum albumin (BSA) from PLGA MS was evaluated in vitro and in vivo by confocal laser microscopy and Kodak imaging. The bioactivities of TGF-β3 and SOX9 were evaluated by assessing α-helical formation using circular dichroism. PLGA MS loaded with FITC-BSA easily entered hMSCs without causing cytotoxicity. To confirm that internalization of PLGA MSs harboring TGF-β3 and SOX9 induced chondrogenesis of hMSCs, we performed several molecular analyses. By analysis, the specific marker gene expression levels in hMSCs adhered onto PLGA MSs coated with TGF-β3 and loaded with SOX9 were more than 3-5 times that of the control group both in vitro and in vivo. This result revealed that PLGA MS uptake and subsequent release of SOX9 induced chondrogenesis of hMSCs was enhanced by coating PLGA MSs with TGF-β3. PMID:27586647

  6. Effect of nanofiber content on bone regeneration of silk fibroin/poly(ε-caprolactone) nano/microfibrous composite scaffolds

    PubMed Central

    Kim, Beom Su; Park, Ko Eun; Kim, Min Hee; You, Hyung Keun; Lee, Jun; Park, Won Ho

    2015-01-01

    The broad application of electrospun nanofibrous scaffolds in tissue engineering is limited by their small pore size, which has a negative influence on cell migration. This disadvantage could be significantly improved through the combination of nano- and microfibrous structure. To accomplish this, different nano/microfibrous scaffolds were produced by hybrid electrospinning, combining solution electrospinning with melt electrospinning, while varying the content of the nanofiber. The morphology of the silk fibroin (SF)/poly(ε-caprolactone) (PCL) nano/microfibrous composite scaffolds was investigated with field-emission scanning electron microscopy, while the mechanical and pore properties were assessed by measurement of tensile strength and mercury porosimetry. To assay cell proliferation, cell viability, and infiltration ability, human mesenchymal stem cells were seeded on the SF/PCL nano/microfibrous composite scaffolds. From in vivo tests, it was found that the bone-regenerating ability of SF/PCL nano/microfibrous composite scaffolds was closely associated with the nanofiber content in the composite scaffolds. In conclusion, this approach of controlling the nanofiber content in SF/PCL nano/microfibrous composite scaffolds could be useful in the design of novel scaffolds for tissue engineering. PMID:25624762

  7. Effect of nanofiber content on bone regeneration of silk fibroin/poly(ε-caprolactone) nano/microfibrous composite scaffolds.

    PubMed

    Kim, Beom Su; Park, Ko Eun; Kim, Min Hee; You, Hyung Keun; Lee, Jun; Park, Won Ho

    2015-01-01

    The broad application of electrospun nanofibrous scaffolds in tissue engineering is limited by their small pore size, which has a negative influence on cell migration. This disadvantage could be significantly improved through the combination of nano- and microfibrous structure. To accomplish this, different nano/microfibrous scaffolds were produced by hybrid electrospinning, combining solution electrospinning with melt electrospinning, while varying the content of the nanofiber. The morphology of the silk fibroin (SF)/poly(ε-caprolactone) (PCL) nano/microfibrous composite scaffolds was investigated with field-emission scanning electron microscopy, while the mechanical and pore properties were assessed by measurement of tensile strength and mercury porosimetry. To assay cell proliferation, cell viability, and infiltration ability, human mesenchymal stem cells were seeded on the SF/PCL nano/microfibrous composite scaffolds. From in vivo tests, it was found that the bone-regenerating ability of SF/PCL nano/microfibrous composite scaffolds was closely associated with the nanofiber content in the composite scaffolds. In conclusion, this approach of controlling the nanofiber content in SF/PCL nano/microfibrous composite scaffolds could be useful in the design of novel scaffolds for tissue engineering. PMID:25624762

  8. Preparation and adsorption properties of magnetic CoFe2O4-chitosan composite microspheres

    NASA Astrophysics Data System (ADS)

    Lian, Qi; Zheng, Xue-Fang; Hu, Tie-Feng

    2015-11-01

    Magnetic chitosan microspheres made from novel polymer materials show outstanding applied characteristics. Magnetic chitosan microspheres are rather cheap, non-toxic, tasteless, alkali resistant, corrosion resistant, easily degradable, easily recyclable, and so on. It can be widely used in many fields. In this paper, magnetic CoFe2O4/chitosan core-shell microspheres are prepared by means of emulsification cross-linking technique using CoFe2O4 as core and glutaric dialdehyde as crosslinking agent. The results demonstrated that the different calcining temperature of magnetic (CoFe2O4) particles, CoFe2O4/chitosan ratio and stirring time of the suspension medium are the most effective parameters that control the size, size distribution, morphology and magnetism of the described microspheres. Finally, the size, morphology and chemical structure of the prepared materials are studied by different methods. The results show that the optimal calcination temperature of magnetic particles is 700°C, the optimal ratio of CoFe2O4/chitosan is 1: 1, ultrasonic dispersion time is 30 min. The prepared chitosan magnetic microspheres have small size and are well dispersed when the stirring time is 3 h. The prepared magnetic chitosan microspheres are well shaped spheres with a diameter from 1 to 50 μm, in which CoFe2O4 particles are dispersed uniformly. The magnetic chitosan microspheres show excellent magnetic response and have good adsorption characteristics.

  9. Variation of mechanical behavior of β-TCP/collagen two phase composite scaffold with mesenchymal stem cell in vitro.

    PubMed

    Arahira, Takaaki; Todo, Mitsugu

    2016-08-01

    The primary aim of this study is to characterize the variational behavior of the compressive mechanical property of bioceramic-based scaffolds using stem cells during the cell culture period. β-Tricalcium phosphate (TCP)/collagen two phase composites and β-TCP scaffolds were fabricated using the polyurethane template technique and a subsequent freeze-drying method. Rat bone-marrow mesenchymal stem cells (rMSCs) were then cultured in these scaffolds for up to 28 days. Compression tests of the scaffolds with rMSCs were periodically conducted. Biological properties, such as the cell number, alkaline phosphatase (ALP) activity, and gene expressions of osteogenesis, were evaluated. The microstructural change due to cell growth and the formation of extracellular matrices was examined using a field-emission scanning electron microscope. The compressive property was then correlated with the biological properties and microstructures to understand the mechanism of the variational behavior of the macroscopic mechanical property. The porous collagen structure in the β-TCP scaffold effectively improved the structural stability of the composite scaffold, whereas the β-TCP scaffold exhibited structural instability with the collapse of the porous structure when immersed in a culture medium. The β-TCP/collagen composite scaffold exhibited higher ALP activity and more active generation of osteoblastic markers than the β-TCP scaffold. PMID:27124803

  10. Biomimetic composite scaffolds based on mineralization of hydroxyapatite on electrospun poly(ɛ-caprolactone)/nanocellulose fibers.

    PubMed

    Si, Junhui; Cui, Zhixiang; Wang, Qianting; Liu, Qiong; Liu, Chuntai

    2016-06-01

    A biomimetic nanocomposite scaffold with HA formation on the electrospun poly(ɛ-caprolactone) (PCL)/nanocellulose (NC) fibrous matrix was developed in this study. The electrospun PCL/NC fiber mat was built and then biomineralized by treatment in simulated body fluid (SBF). Using such a rapid and effective procedure, a continuous biomimetic crystalline HA layer could be successfully formed without the need of any additional chemical modification of the substrate surface. The results showed that the introduction of NC into composite fibers is an effective approach to induce the deposition of HA nucleus as well as to improve their distribution and growth of a crystalline HA layer on the fibrous scaffolds. The water contact angle (WCA) of the PCL/NC/HA scaffolds decreases with increasing NC content and mineralization time, resulting in the enhancement of their hydrophilicity. These results indicated that HA-mineralized on PCL/NC fiber can be prepared directly by simply using SBF immersion. PMID:27083369

  11. Ex vivo human trabecular bone model for biocompatibility evaluation of calcium phosphate composites modified with spray dried biodegradable microspheres.

    PubMed

    Schnieders, Julia; Gbureck, Uwe; Germershaus, Oliver; Kratz, Marita; Jones, David B; Kissel, Thomas

    2013-10-01

    Our aim was to study the suitability of the ex-vivo human trabecular bone bioreactor ZetOS to test the biocompatibility of calcium phosphate bone cement composites modified with spray dried, drug loaded microspheres. We hypothesized, that this bone bioreactor could be a promising alternative to in vivo assessment of biocompatibility in living human bone over a defined time period. Composites consisting of tetracycline loaded poly(lactic-co-glycolic acid) microspheres and calcium phosphate bone cement, were inserted into in vitro cultured human femora head trabecular bone and incubated over 30 days at 37°C in the incubation system. Different biocompatibility parameters, such as lactate dehydrogenase activity, alkaline phosphatase release and the expression of relevant cytokines, IL-1β, IL-6, and TNF-α, were measured in the incubation medium. No significant differences in alkaline phosphatase, osteocalcin, and lactate dehydrogenase activity were measured compared to control samples. Tetracycline was released from the microspheres, delivered and incorporated into newly formed bone. In this study we demonstrated that ex vivo biocompatibility testing using human trabecular bone in a bioreactor is a potential alternative to animal experiments since bone metabolism is still maintained in a physiological environment ex vivo. PMID:23568426

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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.

  13. Tailoring the morphology of raspberry-like carbon black/polystyrene composite microspheres for fabricating superhydrophobic surface

    SciTech Connect

    Bao, Yubin; Li, Qiuying; Xue, Pengfei; Huang, Jianfeng; Wang, Jibin; Guo, Weihong; Wu, Chifei

    2011-05-15

    In our previous report, raspberry-like carbon black/polystyrene (CB/PS) composite microsphere was prepared through heterocoagulation process. Based on the previous study, in the present work, the morphology of raspberry-like CB/PS particle is tailored through adjusting the polarity and the concentration ratio of CB/PS colloidal suspension with the purpose to prepare particulate film for the fabrication of superhydrophobic surface. Scanning electron microscope (SEM) confirms the morphology of raspberry-like particle and the coverage of CB. Rough surfaces fabricated by raspberry-like particles with proper morphology are observed by SEM and clear evidence of superhydrophobic surface is shown. The structure of raspberry-like particle is analyzed by atom force microscope. The proposed relationship between the hydrophobicity and the structure of CB aggregates on the surface of PS microsphere is discussed in details.

  14. Nanocalcium-deficient hydroxyapatite-poly (e-caprolactone)-polyethylene glycol-poly (e-caprolactone) composite scaffolds.

    PubMed

    Wang, Zhiwei; Li, Ming; Yu, Baoqing; Cao, Liehu; Yang, Qingsong; Su, Jiacan

    2012-01-01

    A bioactive composite of nano calcium-deficient apatite (n-CDAP) with an atom molar ratio of calcium to phosphate (Ca/P) of 1.50 and poly(ɛ-caprolactone)-poly(ethylene glycol)-poly(ɛ-caprolactone) (PCL-PEG-PCL) was synthesized, and a composite scaffold was fabricated. The composite scaffolds with 40 wt% n-CDAP contained well interconnected macropores around 400 μm, and exhibited a porosity of 75%. The weight-loss ratio of the n-CDAP/PCL-PEG-PCL was significantly greater than nano hydroxyapatite (n-HA, Ca/P = 1.67)/PCL-PEG-PCL composite scaffolds during soaking into phosphate-buffered saline (pH 7.4) for 70 days, indicating that n-CDAP-based composite had good degradability compared with n-HA. The viability ratio of MG-63 cells was significantly higher on n-CDAP than n-HA-based composite scaffolds at 3 and 5 days. In addition, the alkaline phosphatase activity of the MG-63 cells cultured on n-CDAP was higher than n-HA-based composite scaffolds at 7 days. Histological evaluation showed that the introduction of n-CDAP into PCL-PEG-PCL enhanced the efficiency of new bone formation when the composite scaffolds were implanted into rabbit bone defects. The results suggested that the n-CDAP-based composite exhibits good biocompatibility, biodegradation, and osteogenesis in vivo. PMID:22848159

  15. Adsorption of Cd(II), Cu(II) and Ni(II) ions by cross-linking chitosan/rectorite nano-hybrid composite microspheres.

    PubMed

    Zeng, Lixuan; Chen, Yufei; Zhang, Qiuyun; Guo, Xingmei; Peng, Yanni; Xiao, Huijuan; Chen, Xiaocheng; Luo, Jiwen

    2015-10-01

    Chitosan/rectorie (CTS/REC) nano-hybrid composite microsphere was prepared by changing the proportion of CTS/REC with 2:1, 3:1 and 4:1. Compared with the pure cross-linking chitosan microsphere, the nano-hybrid composite microsphere was proved to have better sorption capacity of Cd(II), Cu(II) and Ni(II), especially 2:1(CTS/REC-1). The adsorption behavior of the microsphere of Cd(II), Cu(II) and Ni(II) was investigated in single and binary metal systems. In single system, the equilibrium studies showed that the adsorption of Cd(II), Cu(II) and Ni(II) followed the Langmuir model and the pseudo-second-order kinetic model. The negative values of (ΔG) suggested that the adsorption process was spontaneous. In binary system, the combined action of the metals was found to be antagonistic and the metal sorption followed the order of Cu(II)>Cd(II)>Ni(II). The regeneration studies indicated that EDTA desorbed Cd(II), Cu(II) and Ni(II) from cross-linking microspheres better than HCl. The FT-IR and XPS spectra showed that coordination bonds were formed between Cd(II), Cu(II) and Ni(II) and the nitrogen atoms of cross-linking CTS/REC nano-hybrid composite microspheres. PMID:26076634

  16. A Hydrogel-Mineral Composite Scaffold for Osteochondral Interface Tissue Engineering

    PubMed Central

    Khanarian, Nora T.; Jiang, Jie; Wan, Leo Q.; Mow, Van C.

    2012-01-01

    Osteoarthritis is the leading cause of physical disability among Americans, and tissue engineered cartilage grafts have emerged as a promising treatment option for this debilitating condition. Currently, the formation of a stable interface between the cartilage graft and subchondral bone remains a significant challenge. This study evaluates the potential of a hybrid scaffold of hydroxyapatite (HA) and alginate hydrogel for the regeneration of the osteochondral interface. Specifically, the effects of HA on the response of chondrocytes were determined, focusing on changes in matrix production and mineralization, as well as scaffold mechanical properties over time. Additionally, the optimal chondrocyte population for interface tissue engineering was evaluated. It was observed that the HA phase of the composite scaffold promoted the formation of a proteoglycan- and type II collagen–rich matrix when seeded with deep zone chondrocytes. More importantly, the elevated biosynthesis translated into significant increases in both compressive and shear moduli relative to the mineral-free control. Presence of HA also promoted chondrocyte hypertrophy and type X collagen deposition. These results demonstrate that the hydrogel–calcium phosphate composite supported the formation of a calcified cartilage-like matrix and is a promising scaffold design for osteochondral interface tissue engineering. PMID:21919797

  17. Biomineralized hydroxyapatite nanoclay composite scaffolds with polycaprolactone for stem cell-based bone tissue engineering.

    PubMed

    Ambre, Avinash H; Katti, Dinesh R; Katti, Kalpana S

    2015-06-01

    Nanoclay modified with unnatural amino acid was used to design a nanoclay-hydroxyapatite (HAP) hybrid by mineralizing HAP in the nanoclay galleries mimicking biomineralization. This hybrid (in situ HAPclay) was used to fabricate polycaprolactone (PCL)/in situ HAPclay films and scaffolds for bone regeneration. Cell culture assays and imaging were used to study interactions between human mesenchymal stem cells (hMSCs) and PCL/in situ HAPclay composites (films and scaffolds). SEM imaging indicated MSC attachment, formation of mineralized extracellular (ECM) on PCL/in situ HAPclay films, and infiltration of MSCs to the interior of PCL/in situ HAPclay scaffolds. Mineralized ECM was formed by MSCs without use of osteogenic supplements. AFM imaging performed on this in vitro generated mineralized ECM on PCL/in situ HAPclay films revealed presence of components (collagen and mineral) of hierarchical organization reminiscent of natural bone. Cellular events observed during two-stage seeding experiments on PCL/in situ HAPclay films indicated similarities with events occurring during in vivo bone formation. PCL/in situ HAPclay films showed significantly increased (100-595% increase in elastic moduli) nanomechanical properties and PCL/in situ HAPclay scaffolds showed increased degradation. This work puts forth PCL/in situ HAPclay composites as viable biomaterials for bone tissue engineering. PMID:25331212

  18. Evaluation of bone matrix gelatin/fibrin glue and chitosan/gelatin composite scaffolds for cartilage tissue engineering.

    PubMed

    Wang, Z H; Zhang, J; Zhang, Q; Gao, Y; Yan, J; Zhao, X Y; Yang, Y Y; Kong, D M; Zhao, J; Shi, Y X; Li, X L

    2016-01-01

    This study was designed to evaluate bone matrix gelatin (BMG)/fibrin glue and chitosan/gelatin composite scaffolds for cartilage tissue engineering. Chondrocytes were isolated from costal cartilage of Sprague-Dawley rats and seeded on BMG/fibrin glue or chitosan/gelatin composite scaffolds. After different in vitro culture durations, the scaffolds were subjected to hematoxylin and eosin, Masson's trichrome, and toluidine blue staining, anti-collagen II and anti-aggrecan immunohistochemistry, and scanning electronic microscopy (SEM) analysis. After 2 weeks of culture, chondrocytes were distributed evenly on the surfaces of both scaffolds. Cell numbers and the presence of extracellular matrix components were markedly increased after 8 weeks of culture, and to a greater extent on the chitosan/gelatin scaffold. The BMG/fibrin glue scaffold showed signs of degradation after 8 weeks. Immunofluorescence analysis confirmed higher levels of collagen II and aggrecan using the chitosan/gelatin scaffold. SEM revealed that the majority of cells on the surface of the BMG/fibrin glue scaffold demonstrated a round morphology, while those in the chitosan/gelatin group had a spindle-like shape, with pseudopodia. Chitosan/gelatin scaffolds appear to be superior to BMG/ fibrin glue constructs in supporting chondrocyte attachment, proliferation, and biosynthesis of cartilaginous matrix components. PMID:27525846

  19. 3D scaffold alters cellular response to graphene in a polymer composite for orthopedic applications.

    PubMed

    Kumar, Sachin; Azam, Dilkash; Raj, Shammy; Kolanthai, Elayaraja; Vasu, K S; Sood, A K; Chatterjee, Kaushik

    2016-05-01

    Graphene-based polymer nanocomposites are being studied for biomedical applications. Polymer nanocomposites can be processed differently to generate planar two-dimensional (2D) substrates and porous three-dimensional (3D) scaffolds. The objective of this work was to investigate potential differences in biological response to graphene in polymer composites in the form of 2D substrates and 3D scaffolds. Polycaprolactone (PCL) nanocomposites were prepared by incorporating 1% of graphene oxide (GO) and reduced graphene oxide (RGO). GO increased modulus and strength of PCL by 44 and 22% respectively, whereas RGO increased modulus and strength by 22 and 16%, respectively. RGO increased the water contact angle of PCL from 81° to 87° whereas GO decreased it to 77°. In 2D, osteoblast proliferated 15% more on GO composites than on PCL whereas RGO composite showed 17% decrease in cell proliferation, which may be attributed to differences in water wettability. In 3D, initial cell proliferation was markedly retarded in both GO (36% lower) and RGO (55% lower) composites owing to increased roughness due to the presence of the protruding nanoparticles. Cells organized into aggregates in 3D in contrast to spread and randomly distributed cells on 2D discs due to the macro-porous architecture of the scaffolds. Increased cell-cell contact and altered cellular morphology led to significantly higher mineralization in 3D. This study demonstrates that the cellular response to nanoparticles in composites can change markedly by varying the processing route and has implications for designing orthopedic implants such as resorbable fracture fixation devices and tissue scaffolds using such nanocomposites. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 732-749, 2016. PMID:26482196

  20. Biodegradable nanofibers-reinforced microfibrous composite scaffolds for bone tissue engineering.

    PubMed

    Martins, Albino; Pinho, Elisabete D; Correlo, Vítor M; Faria, Susana; Marques, Alexandra P; Reis, Rui L; Neves, Nuno M

    2010-12-01

    Native bone extracellular matrix (ECM) is a complex hierarchical fibrous composite structure, resulting from the assembling of collagen fibrils at several length scales, ranging from the macro to the nanoscale. The combination of nanofibers within microfibers after conventional reinforcement methodologies seems to be a feasible solution to the rational design of highly functional synthetic ECM substitutes. The present work aims at the development of bone ECM inspired structures, conjugating electrospun chitosan (Cht) nanofibers within biodegradable polymeric microfibers [poly(butylene succinate)-PBS and PBS/Cht], assembled in a fiber mesh structure. The nanofibers-reinforced composite fiber mesh scaffolds were seeded with human bone marrow mesenchymal stem cells (hBMSCs) and cultured under osteogenic differentiation conditions. These nanofibers-reinforced composite scaffolds sustained ECM deposition and mineralization, mainly in the PBS/Cht-based fiber meshes, as depicted by the increased amount of calcium phosphates produced by the osteogenic differentiated hBMSCs. The osteogenic genotype of the cultured hBMSCs was confirmed by the expression of osteoblastic genes, namely Alkaline Phosphatase, Osteopontin, Bone Sialoprotein and Osteocalcin, and the transcription factors Runx2 and Osterix, all involved in different stages of the osteogenesis. These data represent the first report on the biological functionality of nanofibers-reinforced composite scaffolds, envisaging the applicability of the developed structures for bone tissue engineering. PMID:20666612

  1. [Studies on preparation by SPG membrane emulsification method and in vitro characterization of tetradrine-tashionone II(A)-PLGA composite microspheres].

    PubMed

    Lu, Jin; Zhang, Meng; Zhu, Hua-xu; Guo, Li-wei; Pan, Lin-mei; Fu, Ting-ming

    2015-03-01

    Tetradrine-tashionone II(A)-PLGA composite microspheres were prepared by the SPG membrane emulsification method, and the characterization of tetradrine-tashionone II(A) -PLGA composite microspheres were studied in this experiment. The results of IR, DSC and XRD showed that teradrine and tashionone II(A) in composite microspheres were highly dispersed in the PLGA with amorphous form. The results of tetradrine-tashionone II(A) -PLGA composite microspheres in vitro release experiment showed that the cumulative release amounts of tetradrine and tashionone II(A) were 6.44% and 3.60% in 24 h, and the cumulative release amounts of tetradrine and tashionone II(A) were 89.02% and 21.24% in 17 d. The process of drug in vitro release accorded with the model of Riger-Peppas. Tetradrine-tashionone II(A) -PLGA composite microspheres had slow-release effect, and it could significantly reduce the burst release, prolong the therapeutic time, decrease the dosage of drugs and provide a new idea and method to prepare traditional Chinese medicine compound. PMID:26226751

  2. Composite vascular scaffold combining electrospun fibers and physically-crosslinked hydrogel with copper wire-induced grooves structure.

    PubMed

    Liu, Yuanyuan; Jiang, Chen; Li, Shuai; Hu, Qingxi

    2016-08-01

    While the field of tissue engineered vascular grafts has greatly advanced, many inadequacies still exist. Successfully developed scaffolds require mechanical and structural properties that match native vessels and optimal microenvironments that foster cell integration, adhesion and growth. We have developed a small diameter, three-layered composite vascular scaffold which consists of electrospun fibers and physically-crosslinked hydrogel with copper wire-induced grooves by combining the electrospinning and dip-coating methods. Scaffold morphology and mechanics were assessed, quantified and compared to native vessels. Scaffolds were seeded with Human Umbilical Vein Endothelial Cells (HUVECs), cultured in vitro for 3 days and were evaluated for cell viability and morphology. The results showed that composite scaffolds had adjustable mechanical strength and favorable biocompatibility, which is important in the future clinical application of Tissue-engineered vascular grafts (TEVGs). PMID:26820993

  3. Amino-functionalized core-shell magnetic mesoporous composite microspheres for Pb(II) and Cd(II) removal.

    PubMed

    Tang, Yulin; Liang, Song; Wang, Juntao; Yu, Shuili; Wang, Yilong

    2013-04-01

    Amino-functionalized Fe3O4@mesoporous SiO2 core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb(II) and Cd(II) adsorption. The microspheres were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb(II) and Cd(II) than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb(II) and Cd(II), respectively, implying that adsorption processes involved monolayer adsorption. Pb(II) and Cd(II) adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb(II)- and Cd(II)-loaded microspheres were effectively desorbed using 0.01 mol/L HCl or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb(II) and Cd(II) in wastewater treatment processes. PMID:23923794

  4. Needle-like ion-doped hydroxyapatite crystals influence osteogenic properties of PCL composite scaffolds.

    PubMed

    Guarino, V; Veronesi, F; Marrese, M; Giavaresi, G; Ronca, A; Sandri, M; Tampieri, A; Fini, M; Ambrosio, Luigi

    2016-02-01

    Surface topography and chemistry both play a crucial role on influencing cell response in 3D porous scaffolds in terms of osteogenesis. Inorganic materials with peculiar morphology and chemical functionalities may be proficiently used to improve scaffold properties-in the bulk and along pore surface-promoting in vitro and in vivo osseous tissue in-growth. The present study is aimed at investigating how bone regenerative properties of composite scaffolds made of poly(Ɛ-caprolactone) (PCL) can be augmented by the peculiar properties of Mg(2+) ion doped hydroxyapatite (dHA) crystals, mainly emphasizing the role of crystal shape on cell activities mediated by microstructural properties. At the first stage, the study of mechanical response by crossing experimental compression tests and theoretical simulation via empirical models, allow recognizing a significant contribution of dHA shape factor on scaffold elastic moduli variation as a function of the relative volume fraction. Secondly, the peculiar needle-like shape of dHA crystals also influences microscopic (i.e. crystallinity, adhesion forces) and macroscopic (i.e. roughness) properties with relevant effects on biological response of the composite scaffold: differential scanning calorimetry (DSC) analyses clearly indicate a reduction of crystallization heat-from 66.75 to 43.05 J g(-1)-while atomic force microscopy (AFM) ones show a significant increase of roughness-from (78.15  ±  32.71) to (136.13  ±  63.21) nm-and of pull-off forces-from 33.7% to 48.7%. Accordingly, experimental studies with MG-63 osteoblast-like cells show a more efficient in vitro secretion of alkaline phosphatase (ALP) and collagen I and a more copious in vivo formation of new bone trabeculae, thus suggesting a relevant role of dHA to support the main mechanisms involved in bone regeneration. PMID:26928781

  5. Urchin-like LaVO₄/Au composite microspheres for surface-enhanced Raman scattering detection.

    PubMed

    Chen, Limiao; Wu, Min; Xiao, Chengyuan; Yu, Yifan; Liu, Xiaohe; Qiu, Guanzhou

    2015-04-01

    The availability of sensitive, reproducible and stable substrate is critically important for surface enhanced Raman scattering (SERS)-based application, but it still remains a challenge up to now. In this work, urchin-like LaVO4 microspheres prepared by a hydrothermal method were used as a template to fabricate SERS substrate by deposition of Au nanoparticle onto the surfaces of LaVO4 microspheres. The coverage of Au nanoparticles on the surfaces of LaVO4 microspheres can be easily controlled by varying the amount of Au precursor. SERS measurement showed that the coverage of Au nanoparticles on the surfaces of LaVO4 microspheres had a great effect on SERS activity. The SERS signals collected from 80 microspheres indicated that as-prepared SERS substrate exhibited a good reproducibility. Detection of melamine molecules with a low concentration (1.0×10(-9)M) was used as an example to show the possible application of such substrate. In addition, the effect of iron ion (Fe(3+)) on detection melamine from the mixture of melamine and benzoic acid was also investigated. It was found that the interference of benzoic acid in detecting melamine from the mixture can be removed by adding Fe(3+). PMID:25540824

  6. 3D Printing of Composite Calcium Phosphate and Collagen Scaffolds for Bone Regeneration

    PubMed Central

    Inzana, Jason A.; Olvera, Diana; Fuller, Seth M.; Kelly, James P.; Graeve, Olivia A.; Schwarz, Edward M.; Kates, Stephen L.; Awad, Hani A.

    2014-01-01

    Low temperature 3D printing of calcium phosphate scaffolds holds great promise for fabricating synthetic bone graft substitutes with enhanced performance over traditional techniques. Many design parameters, such as the binder solution properties, have yet to be optimized to ensure maximal biocompatibility and osteoconductivity with sufficient mechanical properties. This study tailored the phosphoric acid-based binder solution concentration to 8.75 wt% to maximize cytocompatibility and mechanical strength, with a supplementation of Tween 80 to improve printing. To further enhance the formulation, collagen was dissolved into the binder solution to fabricate collagen-calcium phosphate composites. Reducing the viscosity and surface tension through a physiologic heat treatment and Tween 80, respectively, enabled reliable thermal inkjet printing of the collagen solutions. Supplementing the binder solution with 1–2 wt% collagen significantly improved maximum flexural strength and cell viability. To assess the bone healing performance, we implanted 3D printed scaffolds into a critically sized murine femoral defect for 9 weeks. The implants were confirmed to be osteoconductive, with new bone growth incorporating the degrading scaffold materials. In conclusion, this study demonstrates optimization of material parameters for 3D printed calcium phosphate scaffolds and enhancement of material properties by volumetric collagen incorporation via inkjet printing. PMID:24529628

  7. 3D PLLA/ibuprofen composite scaffolds obtained by a supercritical fluids assisted process.

    PubMed

    Cardea, S; Baldino, L; Scognamiglio, M; Reverchon, E

    2014-04-01

    The emerging next generation of engineered tissues is based on the development of loaded scaffolds containing bioactive molecules in order to control the cellular function or to interact on the surrounding tissues. Indeed, implantation of engineered biomaterials might cause local inflammation because of the host's immune response; thereby, the use of anti-inflammatory agents, whether steroidal or nonsteroidal is required. One of the most important stages of tissue engineering is the design and the generation of a porous 3D structure, with high porosity, high interconnectivity and homogenous morphology. Various techniques have been reported in the literature for the fabrication of biodegradable scaffolds, but they suffer several limitations. In this study, for the first time, the possibility of generating 3D polymeric scaffolds loaded with an active compound by supercritical freeze extraction process is evaluated; this innovative process combines the advantages of the thermally induced phase separation process and of the supercritical carbon dioxide drying. Poly-L-lactid acid/ibuprofen composite scaffolds characterized by a 3D geometry, micrometric cellular structures and wrinkled pores walls have been obtained; moreover, homogeneous drug distribution and controlled release of the active principle have been assured. PMID:24366467

  8. Tuning dual-drug release from composite scaffolds for bone regeneration.

    PubMed

    Paris, J L; Román, J; Manzano, M; Cabañas, M V; Vallet-Regí, M

    2015-01-01

    This work presents the tuning of drug-loaded scaffolds for bone regeneration as dual-drug delivery systems. Two therapeutic substances, zoledronic acid (anti-osteoporotic drug) and ibuprofen (anti-inflammatory drug) were successfully incorporated in a controlled manner into three dimensional designed porous scaffolds of apatite/agarose composite. A high-performance liquid chromatography method was optimized to separate and simultaneously quantify the two drugs released from the dual-drug codelivery system. The multifunctional porous scaffolds fabricated show a very rapid delivery of anti-inflammatory (interesting to reduce inflammation after implantation), whereas the anti-osteoporotic drug showed sustained release behaviour (important to promote bone regeneration). Since ibuprofen release was faster than desired, this drug was encapsulated in chitosan spheres which were then incorporated into the scaffolds, obtaining a release profile suitable for clinical application. The results obtained open the possibility to simultaneously incorporate two or more drugs to an osseous implant in a controlled way improving it for bone healing application. PMID:25814035

  9. Preparation and Characterization of SiO 2/TiO 2 composite microspheres with microporous SiO 2 core/mesoporous TiO 2 shell

    NASA Astrophysics Data System (ADS)

    Zhao, Li; Yu, Jiaguo; Cheng, Bei

    2005-06-01

    SiO 2/TiO 2 composite microspheres with microporous SiO 2 core/mesoporous TiO 2 shell structures were prepared by hydrolysis of titanium tetrabutylorthotitanate (TTBT) in the presence of microporous silica microspheres using hydroxypropyl cellulose (HPC) as a surface esterification agent and porous template, and then dried and calcined at different temperatures. The as-prepared products were characterized with differential thermal analysis and thermogravimetric (DTA/TG), scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption. The results showed that composite particles were about 1.8 μm in diameter, and had a spherical morphology and a narrow size distribution. Uniform mesoporous titania coatings on the surfaces of microporous silica microspheres could be obtained by adjusting the HPC concentration to an optimal concentration of about 3.2 mmol L -1. The anatase and rutile phase in the SiO 2/TiO 2 composite microspheres began to form at 700 and 900 °C, respectively. At 700 °C, the specific surface area and pore volume of the SiO 2/TiO 2 composite microspheres were 552 and 0.652 mL g -1, respectively. However, at 900 °C, the specific surface area and pore volume significantly decreased due to the phase transformation from anatase to rutile.

  10. IMPACT OF COMPOSITION AND HEAT TREATMENT ON PORE SIZE IN POROUS WALLED HOLLOW GLASS MICROSPHERES

    SciTech Connect

    Raszewski, F; Erich Hansen, E; Ray Schumacher, R; David Peeler, D

    2007-12-04

    The Savannah River National Laboratory (SRNL) developed a new geometric form: hollow glass microspheres (HGMs), with unique porous walls. The new geometric form combines the existing technology of HGMs with basic glass science knowledge in the realm of glass-in-glass phase separation. Conceptually, the development of a HGM with porous walls (referred to as a PWHGM) provides a unique system in which various media or filling agents can be incorporated into the PWHGM (via transport through the porous walls) and ultimately has the capacity to serve as a functional delivery system in various industrial applications. Applications of these types of systems could range from hydrogen storage, molecular sieves, drug and bioactive delivery systems, to environmental, chemical and biological indicators, relevant to Energy, Environmental Processing and Homeland Security fields. As a specific example, previous studies at SRNL have introduced materials capable of hydrogen storage (as well as other materials) into the interior of the PWHGMs. The goal of this project was to determine if the microstructure (i.e., pore size and pore size distribution) of a PWHGM could be altered or tailored by varying composition and/or heat treatment (time and/or temperature) conditions. The ability to tailor the microstructure through composition or heat treatments could provide the opportunity to design the PWHGM system to accommodate different additives or fill agents. To meet this objective, HGMs of various alkali borosilicate compositions were fabricated using a flame forming apparatus installed at the Aiken County Technical Laboratory (ACTL). HGMs were treated under various heat treatment conditions to induce and/or enhance glass in glass phase separation. Heat treatment temperatures ranged from 580 C to 620 C, while heat treatment times were either 8 or 24 hours. Of the two primary variables assessed in this study, heat treatment temperature was determined to be most effective in changing the

  11. [Strategies to choose scaffold materials for tissue engineering].

    PubMed

    Gao, Qingdong; Zhu, Xulong; Xiang, Junxi; Lü, Yi; Li, Jianhui

    2016-02-01

    Current therapies of organ failure or a wide range of tissue defect are often not ideal. Transplantation is the only effective way for long time survival. But it is hard to meet huge patients demands because of donor shortage, immune rejection and other problems. Tissue engineering could be a potential option. Choosing a suitable scaffold material is an essential part of it. According to different sources, tissue engineering scaffold materials could be divided into three types which are natural and its modified materials, artificial and composite ones. The purpose of tissue engineering scaffold is to repair the tissues or organs damage, so could reach the ideal recovery in its function and structure aspect. Therefore, tissue engineering scaffold should even be as close as much to the original tissue or organs in function and structure. We call it "organic scaffold" and this strategy might be the drastic perfect substitute for the tissues or organs in concern. Optimized organization with each kind scaffold materials could make up for biomimetic structure and function of the tissue or organs. Scaffold material surface modification, optimized preparation procedure and cytosine sustained-release microsphere addition should be considered together. This strategy is expected to open new perspectives for tissue engineering. Multidisciplinary approach including material science, molecular biology, and engineering might find the most ideal tissue engineering scaffold. Using the strategy of drawing on each other strength and optimized organization with each kind scaffold material to prepare a multifunctional biomimetic tissue engineering scaffold might be a good method for choosing tissue engineering scaffold materials. Our research group had differentiated bone marrow mesenchymal stem cells into bile canaliculi like cells. We prepared poly(L-lactic acid)/poly(ε-caprolactone) biliary stent. The scaffold's internal played a part in the long-term release of cytokines which

  12. Lignocellulose Nanofiber-Reinforced Polystyrene Produced from Composite Microspheres Obtained in Suspension Polymerization Shows Superior Mechanical Performance.

    PubMed

    Ballner, Daniel; Herzele, Sabine; Keckes, Jozef; Edler, Matthias; Griesser, Thomas; Saake, Bodo; Liebner, Falk; Potthast, Antje; Paulik, Christian; Gindl-Altmutter, Wolfgang

    2016-06-01

    A facile approach to obtaining cellulose nanofiber-reinforced polystyrene with greatly improved mechanical performance compared to unreinforced polystyrene is presented. Cellulose nanofibers were obtained by mechanical fibrillation of partially delignified wood (MFLC) and compared to nanofibers obtained from bleached pulp. Residual hemicellulose and lignin imparted amphiphilic surface chemical character to MFLC, which enabled the stabilization of emulsions of styrene in water. Upon suspension polymerization of styrene from the emulsion, polystyrene microspheres coated in MFLC were obtained. When processed into polymer sheets by hot-pressing, improved bending strength and superior impact toughness was observed for the polystyrene-MFLC composite compared to the un-reinforced polystyrene. PMID:27163488

  13. [Research progress on application of carbon nanotubes in bone tissue engineering scaffold].

    PubMed

    Yao, Mengzhu; Sheng, Xiaoxia; Lin, Jun; Gao, Jianqing

    2016-03-01

    Carbon nanotubes possess excellent mechanical and electrical properties and demonstrate broad application prospects in medical fields. Carbon nanotubes are composed of inorganic materials, natural biodegradable polymer or synthetic biodegradable polymer. The composite bone tissue engineering scaffolds are constructed by particle-hole method, lyophilization, microsphere aggregation method, electrostatic spinning or three-dimensional printing. Composite scaffolds overcome the shortcomings of single material and have good biocompatibility, osteoconduction and osteoinduction. With the study of surface chemistry, toxicology, and biocompatibility, a degradable "human-friendly" carbon nanotubes composite bone tissue scaffold will be available; and under the drive of new fabrication techniques, the clinical application of carbon nanotubes composite bone tissue engineering scaffolds will be better developed. PMID:27273990

  14. The evaluation of physical properties and in vitro cell behavior of PHB/PCL/sol-gel derived silica hybrid scaffolds and PHB/PCL/fumed silica composite scaffolds.

    PubMed

    Ding, Yaping; Yao, Qingqing; Li, Wei; Schubert, Dirk W; Boccaccini, Aldo R; Roether, Judith A

    2015-12-01

    PHB/PCL/sol-gel derived silica hybrid scaffolds (P5S1S) and PHB/PCL/fumed silica composite scaffolds (P5S1N) with a 5:1 organic/inorganic ratio were fabricated through a combination of electrospinning and sol-gel methods and dispersion electrospinning, respectively. In contrast to the silica nanoparticle aggregates appearing on the fiber surface of P5S1N, smooth and uniform fibers were obtained for P5S1S. The fiber diameter distribution, tensile strength, thermal gravimetric analysis (TGA), and cellular behavior of both types of scaffolds were characterized and studied. The tensile strength results and TGA indicated that the interfacial interaction between the organic and the inorganic phase was enhanced in P5S1S over the nanocomposite scaffolds, and cells exhibited significantly higher alkaline phosphate activity (ALP) for P5S1S, which makes P5S1S hybrid scaffolds candidate materials for bone tissue engineering applications. PMID:26364089

  15. Development of nano-sized hydroxyapatite reinforced composites for tissue engineering scaffolds.

    PubMed

    Huang, Jie; Lin, Yu Wan; Fu, Xiao Wei; Best, Serena M; Brooks, Roger A; Rushton, Neil; Bonfield, William

    2007-11-01

    Nano-sized hydroxyapatite (nanoHA) reinforced composites, mimicking natural bone, were produced. Examination by transmission electron microscopy revealed that the nanoHA particles had a rod-like morphology, 20-30 nm in width and 50-80 nm in length. The phase composition of hydroxyapatite was confirmed by X-ray diffraction. The nanoHA particles were incorporated into poly-2-hydroxyethylmethacrylate (PHEMA)/polycaprolactone (PCL) matrix to make new nanocomposites: nanoHA-PHEMA/PCL. Porous nanocomposite scaffolds were then produced using a porogen leaching method. The interconnectivity of the porous structure of the scaffolds was revealed by non-destructive X-ray microtomography. Porosity of 84% was achieved and pore sizes were approximately around 300-400 microm. An in vitro study found that the nanocomposites were bioactive as indicated by the formation of a bone-like apatite layer after immersion in simulated body fluid. Furthermore, the nanocomposites were able to support the growth and proliferation of primary human osteoblast (HOB) cells. HOB cells developed a well organized actin cytoskeletal protein on the nanocomposite surface. The results demonstrate the potential of the nanocomposite scaffolds for tissue engineering applications for bone repair. PMID:17891551

  16. A new composite scaffold of bioactive glass nanoparticles/graphene: Synchronous improvements of cytocompatibility and mechanical property.

    PubMed

    Fan, Zengjie; Wang, Jinqing; Liu, Fengzhen; Nie, Yingying; Ren, Liling; Liu, Bin

    2016-09-01

    This study presents a simple method of synthesizing bioactive glass nanoparticles/graphene nanosheets composite (BGs/GNS) scaffolds using the sol-gel and mold-compressing strategies. Characterizations of BGs/GNS scaffold revealed that BGs with an average diameter of 28.75nm were densely anchored onto both sides of GNS. When the mass ratio of BGs to graphene oxide was set as 10, this scaffold showed better cytocompatibility and higher osseointegration ability with surrounding tissues than the other scaffolds. The introduction of GNS also significantly enhanced the hardness and Young's modulus of BGs. Given the excellent performance of this scaffold, it has potential applications in bone regeneration and implantation. PMID:27232307

  17. Composite three-dimensional woven scaffolds with interpenetrating network hydrogels to create functional synthetic articular cartilage.

    PubMed

    Liao, I-Chien; Moutos, Franklin T; Estes, Bradley T; Zhao, Xuanhe; Guilak, Farshid

    2013-12-17

    The development of synthetic biomaterials that possess mechanical properties that mimic those of native tissues remains an important challenge to the field of materials. In particular, articular cartilage is a complex nonlinear, viscoelastic, and anisotropic material that exhibits a very low coefficient of friction, allowing it to withstand millions of cycles of joint loading over decades of wear. Here we show that a three-dimensionally woven fiber scaffold that is infiltrated with an interpenetrating network hydrogel can provide a functional biomaterial that provides the load-bearing and tribological properties of native cartilage. An interpenetrating dual-network "tough-gel" consisting of alginate and polyacrylamide was infused into a porous three-dimensionally woven poly(ε-caprolactone) fiber scaffold, providing a versatile fiber-reinforced composite structure as a potential acellular or cell-based replacement for cartilage repair. PMID:24578679

  18. In-situ synthesis and normal chromatographic properties of nonporous SiO2/ZrO2 core-shell composite microspheres.

    PubMed

    Li, Jia; Zhang, Hong-Fei; Shi, Yan-Ping

    2011-01-01

    Sub-2 µm core-shell SiO(2)/ZrO(2) composite microspheres with nonporous SiO(2) as the cores and ZrO(2) nanoparticles as the shells were synthesized by sol-gel method in the current work. The fabrication consisted of (1) preparing monodisperse silica spheres; (2) coating the spheres with zirconia nanoparticles in-situ; and (3) calcining the composite microspheres at 823 K. Then uniform, regular, and ordered arrays of nanometer-scale zirconia crystalline particles were formed and dispersed on the surfaces of nonporous silica microspheres. A potential deposition mechanism in the synthesis process was proposed according to isoelectric point theory and to observe microstructural characteristics. The result showed that this stationary phase also has an advantage in the separation of basic compounds in the normal phase. PMID:21478623

  19. Hierarchical NiO-SiO2 composite hollow microspheres with enhanced adsorption affinity towards Congo red in water.

    PubMed

    Lei, Chunsheng; Zhu, Xiaofeng; Zhu, Bicheng; Yu, Jiaguo; Ho, Wingkei

    2016-03-15

    Hollow microspheres and hierarchical porous nanostructured materials with desired morphologies have gained remarkable attention for their potential applications in environmental technology. In this study, NiO-SiO2 hollow microspheres were prepared by co-precipitation with SiO2 and nickel salt as precursors, followed by dipping in alkaline solution and calcination. The samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption, and X-ray photoelectron spectroscopy. The synthesized hollow spheres were composed of a SiO2 shell and hierarchical porous NiO nanosheets on the surface. Adsorption experiments suggested that NiO-SiO2 composite particles were powerful adsorbents for removal of Congo red from water, with a maximum adsorption capacity of 204.1 mg/g. The high specific surface areas, hollow structures, and hierarchical porous surfaces of the hollow composite particles are suitable for various applications, including adsorption of pollutants, chemical separation, and water purification. PMID:26724707

  20. [Adsorption of the TiO2 @ yeast composite microspheres for adsorbing Fluorescent Whitening Agent-VBL in fixed bed].

    PubMed

    Wu, Fei; Zhang, Kai-Qiang; Bai, Bo; Wang, Hong-Lun; Suo, You-Rui

    2015-02-01

    In this work, the adsorption potential of TiO2@ yeast composite microspheres to remove Fluorescent Whitening Agent-VBL (FWA-VBL) from aqueous solution was investigated using fixed-bed adsorption column. The effects of pH(2.0-8.0), bed height (1-3 cm), inlet concentration (20-80 mg x L(-1)) and feed flow rate (5-11 mL x min(-1)) on the breakthrough characteristics of the adsorption system were determined. The results showed that the highest bed capacity of 223.80 mg x g(-1) was obtained under the condition of pH 2.0, 80 mg x L(-1) inlet dye concentration, 1.0 cm bed height and 5 mL x min(-1) flow rate. The adsorption data were fitted to three well-established fixed-bed adsorption models, namely, BDST model, Thomas model and Yoon-Nelson model. The results fitted well to the three models with coefficients of correlation R2 > 0.980 in different conditions. The TiO2 @ yeast composite microspheres have desired regeneration ability and could be reused for four times. PMID:26031081

  1. Simultaneous removal of acid green 25 and mercury ions from aqueous solutions using glutamine modified chitosan magnetic composite microspheres.

    PubMed

    Tao, Xue; Li, Kun; Yan, Han; Yang, Hu; Li, Aimin

    2016-02-01

    In this current work, the magnetic composite microsphere containing glutamine modified chitosan and silica coated Fe3O4 nanoparticles (CS-Gln-MCM) has been successfully prepared and extensively characterized, which is a kind of biodegradable materials. CS-Gln-MCM shows enhanced removal efficiency for both acid green 25 (AG25), an amphoteric dye, and mercury ions (Hg(2+)) from water in the respective while measured pH range compared with chitosan magnetic composite microsphere (CS-MCM) without modification. It is due to the fact that the grafted amino acid provides a variety of additional adsorption active sites and diverse adsorption mechanisms are involved. In AG25 and Hg(2+) aqueous mixture, the modified adsorbents bear preferential adsorption for AG25 over Hg(2+) in strong acidic solutions ascribed to multiple interactions between AG25 and CS-Gln-MCM, such as hydrogen bonding and electrostatic interactions. While, in weak acidic conditions, an efficient simultaneous removal is observed for different adsorption effects involved in aforementioned two pollutants. Besides, CS-Gln-MCM illuminates not only short equilibrium time for adsorption of each pollutant less than 20.0 min but also rapid magnetic separation from water and efficient regeneration after saturated adsorption. Therefore, CS-Gln-MCM bears great application potentials in water treatment. PMID:26618263

  2. Synthesis of P(AM-co-MAA)/AEM composite microspheres with lichi-like surface structure using porous microgel as template.

    PubMed

    Yang, Juxiang; Hu, Daodao; Xue, Min; Yang, Xing

    2014-03-15

    The P(AM-co-MAA)/AEM composite microspheres with lichi-like structure were synthesized by the hydrolysis and condensation of 3-(trimethoxysilyl)-propyldimethyloctadecyl-ammonium chloride (AEM) located within porous poly(acrylamide-co-methylacrylic acid) (P(AM-co-MAA)) microgels in an ammonia water atmosphere. The morphology and composition of the composite microspheres were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectrometer (FI-IR), and X-ray photoelectron spectroscopy (XPS), respectively. The results indicated that the composite microspheres with lichi-like surface structure could be obtained by controlling the loaded amount of AEM, the hydrolysis-condensation time of AEM, and the cross-linking degree of the porous P(AM-co-MAA) microgels. On the basis of the results, the mechanism on the formation of the microspheres with lichi-like surface structure was proposed. The multiple factors play a role in the formation of the specific surface morphology. The pores of the porous microgels make AEM behavior localized; the migration of AEM along with solvent evaporation leads to the structural change; the hydrolysis-condensation of AEM brings the temporarily structural solidification; the surface tension of hydrophobic AEM in hydrophilic atmosphere induces AEM liquid membrane constriction. Although the mechanism is complicated, the method is very simple. Based on the analogous principle, other composite materials with lichi-like structure could be constructed by altering precursor and porous template. PMID:24461855

  3. Fabrication and in vitro evaluation of a sponge-like bioactive-glass/gelatin composite scaffold for bone tissue engineering.

    PubMed

    Nadeem, Danish; Kiamehr, Mostafa; Yang, Xuebin; Su, Bo

    2013-07-01

    In this work a bioactive composite scaffold, comprised of bioactive-glass and gelatin, is introduced. Through direct foaming a sponge-like composite of a sol-gel derived bioactive-glass (70S30C; 70% SiO2, 30% CaO) and porcine gelatin was developed for use as a biodegradable scaffold for bone tissue engineering. The composite was developed to provide a suitable alternative to synthetic polymer based scaffolds, allowing directed regeneration of bone tissue. The fabricated scaffold was characterised through X-ray microtomography, scanning electron and light microscopy demonstrating a three dimensionally porous and interconnected structure, with an average pore size (170 μm) suitable for successful cell proliferation and tissue ingrowth. Acellular bioactivity was assessed through apatite formation during submersion in simulated body fluid (SBF) whereby the rate and onset of apatite nucleation was found to be comparable to that of bioactive-glass. Modification of dehydrothermal treatment parameters induced varying degrees of crosslinking, allowing the degradation of the composite to be tailored to suit specific applications and establishing its potential for a wide range of applications. Use of genipin to supplement crosslinking by dehydrothermal treatment provided further means of modifying degradability. Biocompatibility of the composite was qualified through successful cultures of human dental pulp stem cells (HDPSCs) on samples of the composite scaffold. Osteogenic differentiation of HDPSCs and extracellular matrix deposition were confirmed through positive alkaline phosphatase staining and immunohistochemistry. PMID:23623083

  4. Nanofiber–microsphere (nano-micro) matrices for bone regenerative engineering: a convergence approach toward matrix design

    PubMed Central

    Nelson, Clarke; Khan, Yusuf; Laurencin, Cato T.

    2014-01-01

    Bone is an essential organ for health and quality of life. Due to current shortfalls in therapy for bone tissue engineering, scientists have sought the application of synthetic materials as bone graft substitutes. As a composite organic/inorganic material with significant extra cellular matrix (ECM), one way to improve bone graft substitutes may be to engineer a synthetic matrix that is influenced by the physical appearance of natural ECM networks. In this work, the authors evaluate composite, hybrid scaffolds for bone tissue engineering based on composite ceramic/polymer microsphere scaffolds with synthetic ECM-mimetic networks in their pore spaces. Using thermally induced phase separation, nanoscale fibers were deposited in the pore spaces of structurally sound microsphere-based scaffold with a density proportionate to the initial polymer concentration. Porosimetry and mechanical testing indicated no significant changes in overall pore characteristics or mechanical integrity as a result of the fiber deposition process. These scaffolds displayed adequate mechanical integrity on the scale of human trabecular bone and supported the adhesion and proliferation of cultured mouse calvarial osteoblasts. Drawing from natural cues, these scaffolds may represent a new avenue forward for advanced bone tissue engineering scaffolds. PMID:26816620

  5. Gas foamed open porous biodegradable polymeric microspheres.

    PubMed

    Kim, Taek Kyoung; Yoon, Jun Jin; Lee, Doo Sung; Park, Tae Gwan

    2006-01-01

    Highly open porous biodegradable polymeric microspheres were fabricated for use as injectable scaffold microcarriers for cell delivery. A modified water-in-oil-in-water (W1/O/W2) double emulsion solvent evaporation method was employed for producing the microspheres. The incorporation of an effervescent salt, ammonium bicarbonate, in the primary W1 droplets spontaneously produced carbon dioxide and ammonia gas bubbles during the solvent evaporation process, which not only stabilized the primary emulsion, but also created well inter-connected pores in the resultant microspheres. The porous microspheres fabricated under various gas foaming conditions were characterized. The surface pores became as large as 20 microm in diameter with increasing the concentration of ammonium bicarbonate, being sufficient enough for cell infiltration and seeding. These porous scaffold microspheres could be potentially utilized for cultivating cells in a suspension manner and for delivering the seeded cells to the tissue defect site in an injectable manner. PMID:16023197

  6. Structural modification and characterization of bacterial cellulose-alginate composite scaffolds for tissue engineering.

    PubMed

    Kirdponpattara, Suchata; Khamkeaw, Arnon; Sanchavanakit, Neeracha; Pavasant, Prasit; Phisalaphong, Muenduen

    2015-11-01

    A novel bacterial cellulose-alginate composite scaffold (N-BCA) was fabricated by freeze drying and subsequent crosslinking with Ca(2+). The N-BCA then underwent a second freeze drying step to remove water without altering the physical structure. A stable structure of N-BCA with open and highly interconnected pores in the range of 90-160 μm was constructed. The N-BCA was stable in both water and PBS. The swelling ability of N-BCA in water was approximately 50 times its weight, which was about 6.5 times that of the freeze dried bacterial cellulose pellicles. N-BCA demonstrated no cytotoxicity against L929 mouse fibroblast cells. For long-term culture, N-BCA supported attachment, spreading, and proliferation of human gingival fibroblast (GF) on the surface. However, under static conditions, the cell migration and growth inside the scaffold were limited. Because of its biocompatibility and open macroporous structure, N-BCA could potentially be used as a scaffold for tissue engineering. PMID:26256335

  7. Nanomechanical properties of electrospun composite scaffolds based on polycaprolactone and hydroxyapatite.

    PubMed

    Tyagi, Parul; Catledge, Shane A; Stanishevsky, Andrei; Thomas, Vinoy; Vohra, Y K

    2009-08-01

    Fibrous nanocomposite scaffolds were electrospun from dispersions of hydroxyapatite nanoparticles (nanoHA) in polycaprolactone (PCL) with varying nanoHA contents (from 0% to 50% by weight). Such scaffolds were produced to mimic the nano-features of the extracellular matrix (ECM) for natural bone tissue regeneration. NanoHA was found to be well dispersed in the PCL fibers up to the addition of 30 wt%, whereas beads and agglomeration of HA particles was observed above this nanoHA concentration. The structural and morphological characterizations were evaluated by scanning electron microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD). The average fiber diameter decreased with increased nanoHA concentration. The nanomechanical properties of the as-spun fibrous scaffolds as well as pressure-consolidated (pelletized) composites were evaluated by nanoindentation. Elastic modulus increased with increasing HA content, but was especially pronounced for 40-50% HA content where the indenter tip is more likely to probe agglomerated HA particles. PMID:19928159

  8. Composite scaffolds for controlled drug release: role of the polyurethane nanoparticles on the physical properties and cell behaviour.

    PubMed

    Gentile, Piergiorgio; Bellucci, Devis; Sola, Antonella; Mattu, Clara; Cannillo, Valeria; Ciardelli, Gianluca

    2015-04-01

    Localised delivery of appropriate biomolecule/drug(s) can be suitable to prevent postoperative infections and inflammation after scaffold implantation in vivo. In this study composite shell scaffolds, based on an internally produced bioactive glass and a commercial hydroxyapatite, were surface coated with a uniform polymeric layer, embedded with thermo-stable polyesterurethane (PU)-based nanoparticles (NPs), containing an anti-inflammatory drug (indomethacin; IDCM). The obtained functionalised scaffolds were subjected to physico-mechanical and biological characterisations. The results indicated that NPs incorporation into the gelatin coating of the composite scaffolds: 1) not changed significantly the micro-architecture of the scaffolds in terms of mean pore diameter and pore size distribution; 2) increased the compressive modulus; and 3) allowed to a sustained IDMC release (65-70% of the loaded-drug) within the first week of incubation in physiological solution. On the other hand, the NPs incorporation did not affect the biocompatibility of composite scaffolds, as evidenced by viability and alkaline phosphatase (ALP) activity of MG63 human osteoblast-like cells. PMID:25617789

  9. A composite scaffold of MSC affinity peptide-modified demineralized bone matrix particles and chitosan hydrogel for cartilage regeneration

    PubMed Central

    Meng, Qingyang; Man, Zhentao; Dai, Linghui; Huang, Hongjie; Zhang, Xin; Hu, Xiaoqing; Shao, Zhenxing; Zhu, Jingxian; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Ao, Yingfang

    2015-01-01

    Articular cartilage injury is still a significant challenge because of the poor intrinsic healing potential of cartilage. Stem cell-based tissue engineering is a promising technique for cartilage repair. As cartilage defects are usually irregular in clinical settings, scaffolds with moldability that can fill any shape of cartilage defects and closely integrate with the host cartilage are desirable. In this study, we constructed a composite scaffold combining mesenchymal stem cells (MSCs) E7 affinity peptide-modified demineralized bone matrix (DBM) particles and chitosan (CS) hydrogel for cartilage engineering. This solid-supported composite scaffold exhibited appropriate porosity, which provided a 3D microenvironment that supports cell adhesion and proliferation. Cell proliferation and DNA content analysis indicated that the DBM-E7/CS scaffold promoted better rat bone marrow-derived MSCs (BMMSCs) survival than the CS or DBM/CS groups. Meanwhile, the DBM-E7/CS scaffold increased matrix production and improved chondrogenic differentiation ability of BMMSCs in vitro. Furthermore, after implantation in vivo for four weeks, compared to those in control groups, the regenerated issue in the DBM-E7/CS group exhibited translucent and superior cartilage-like structures, as indicated by gross observation, histological examination, and assessment of matrix staining. Overall, the functional composite scaffold of DBM-E7/CS is a promising option for repairing irregularly shaped cartilage defects. PMID:26632447

  10. Preparation of a biomimetic composite scaffold from gelatin/collagen and bioactive glass fibers for bone tissue engineering.

    PubMed

    Sharifi, Esmaeel; Azami, Mahmoud; Kajbafzadeh, Abdol-Mohammad; Moztarzadeh, Fatollah; Faridi-Majidi, Reza; Shamousi, Atefeh; Karimi, Roya; Ai, Jafar

    2016-02-01

    Bone tissue is a composite material made of organic and inorganic components. Bone tissue engineering requires scaffolds that mimic bone nature in chemical and mechanical properties. This study proposes a novel method for preparing composite scaffolds that uses sub-micron bioglass fibers as the organic phase and gelatin/collagen as the inorganic phase. The scaffolds were constructed by using freeze drying and electro spinning methods and their mechanical properties were enhanced by using genipin crosslinking agent. Electron microscopy micrographs showed that the structure of composite scaffolds were porous with pore diameters of approximately 70-200μm, this was again confirmed by mercury porosimetery. These pores are suitable for osteoblast growth. The diameters of the fibers were approximately 150-450nm. Structural analysis confirmed the formation of desirable phases of sub-micron bioglass fibers. Cellular biocompatibility tests illustrated that scaffolds containing copper ion in the bioglass structure had more cell growth and osteoblast attachment in comparison to copper-free scaffolds. PMID:26652405

  11. A composite scaffold of MSC affinity peptide-modified demineralized bone matrix particles and chitosan hydrogel for cartilage regeneration

    NASA Astrophysics Data System (ADS)

    Meng, Qingyang; Man, Zhentao; Dai, Linghui; Huang, Hongjie; Zhang, Xin; Hu, Xiaoqing; Shao, Zhenxing; Zhu, Jingxian; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Ao, Yingfang

    2015-12-01

    Articular cartilage injury is still a significant challenge because of the poor intrinsic healing potential of cartilage. Stem cell-based tissue engineering is a promising technique for cartilage repair. As cartilage defects are usually irregular in clinical settings, scaffolds with moldability that can fill any shape of cartilage defects and closely integrate with the host cartilage are desirable. In this study, we constructed a composite scaffold combining mesenchymal stem cells (MSCs) E7 affinity peptide-modified demineralized bone matrix (DBM) particles and chitosan (CS) hydrogel for cartilage engineering. This solid-supported composite scaffold exhibited appropriate porosity, which provided a 3D microenvironment that supports cell adhesion and proliferation. Cell proliferation and DNA content analysis indicated that the DBM-E7/CS scaffold promoted better rat bone marrow-derived MSCs (BMMSCs) survival than the CS or DBM/CS groups. Meanwhile, the DBM-E7/CS scaffold increased matrix production and improved chondrogenic differentiation ability of BMMSCs in vitro. Furthermore, after implantation in vivo for four weeks, compared to those in control groups, the regenerated issue in the DBM-E7/CS group exhibited translucent and superior cartilage-like structures, as indicated by gross observation, histological examination, and assessment of matrix staining. Overall, the functional composite scaffold of DBM-E7/CS is a promising option for repairing irregularly shaped cartilage defects.

  12. CO2-assisted high pressure homogenization: a solvent-free process for polymeric microspheres and drug-polymer composites.

    PubMed

    Kluge, Johannes; Mazzotti, Marco

    2012-10-15

    The study explores the enabling role of near-critical CO(2) as a reversible plasticizer in the high pressure homogenization of polymer particles, aiming at their comminution as well as at the formation of drug-polymer composites. First, the effect of near-critical CO(2) on the homogenization of aqueous suspensions of poly lactic-co-glycolic acid (PLGA) was investigated. Applying a pressure drop of 900 bar and up to 150 passes across the homogenizer, it was found that particles processed in the presence of CO(2) were generally of microspherical morphology and at all times significantly smaller than those obtained in the absence of a plasticizer. The smallest particles, exhibiting a median x(50) of 1.3 μm, were obtained by adding a small quantity of ethyl acetate, which exerts on PLGA an additional plasticizing effect during the homogenization step. Further, the study concerns the possibility of forming drug-polymer composites through simultaneous high pressure homogenization of the two relevant solids, and particularly the effect of near-critical CO(2) on this process. Therefore, PLGA was homogenized together with crystalline S-ketoprofen (S-KET), a non-steroidal anti-inflammatory drug, at a drug to polymer ratio of 1:10, a pressure drop of 900 bar and up to 150 passes across the homogenizer. When the process was carried out in the presence of CO(2), an impregnation efficiency of 91% has been reached, corresponding to 8.3 wt.% of S-KET in PLGA; moreover, composite particles were of microspherical morphology and significantly smaller than those obtained in the absence of CO(2). The formation of drug-polymer composites through simultaneous homogenization of the two materials is thus greatly enhanced by the presence of CO(2), which increases the efficiency for both homogenization and impregnation. PMID:22750408

  13. Preparation and characterization of nano-sized hydroxyapatite/alginate/chitosan composite scaffolds for bone tissue engineering.

    PubMed

    Kim, Hye-Lee; Jung, Gil-Yong; Yoon, Jun-Ho; Han, Jung-Suk; Park, Yoon-Jeong; Kim, Do-Gyoon; Zhang, Miqin; Kim, Dae-Joon

    2015-09-01

    The aim of this study was to develop chitosan composite scaffolds with high strength and controlled pore structures by homogenously dispersed nano-sized hydroxyapatite (nano-HAp) powders. In the fabrication of composite scaffolds, nano-HAp powders distributed in an alginate (AG) solution with a pH higher than 10 were mixed with a chitosan (CS) solution and then freeze dried. While the HAp content increased up to 70 wt.%, the compressive strength and the elastic modulus of the composite scaffolds significantly increased from 0.27 MPa and 4.42 MPa to 0.68 MPa and 13.35 MPa, respectively. Higher content of the HAp also helped develop more differentiation and mineralization of the MC3T3-E1 cells on the composite scaffolds. The uniform pore structure and the excellent mechanical properties of the HAp/CS composite scaffolds likely resulted from the use of the AG solution at pH 10 as a dispersant for the nano-HAp powders. PMID:26046263

  14. Strontium doped poly-ε-caprolactone composite scaffolds made by reactive foaming.

    PubMed

    Zehbe, Rolf; Zehbe, Kerstin

    2016-10-01

    In the reconstruction and regeneration of bone tissue, a primary goal is to initiate bone growth and to stabilize the surrounding bone. In this regard, a potentially useful component in biomaterials for bone tissue engineering is strontium, which acts as cationic active agent, triggering certain intracellular pathways and acting as so called dual action bone agent which inhibits bone resorption while stimulating bone regeneration. In this study we established a novel processing for the foaming of a polymer (poly-ε-caprolactone) and simultaneous chemical reaction of a mixture of calcium and strontium hydroxides to the respective carbonates using supercritical carbon dioxide. The resultant porous composite scaffold was optimized in composition and strontium content and was characterized via different spectroscopic (infrared and Raman spectroscopy, energy dispersive X-ray spectroscopy), imaging (SEM, μCT), mechanical testing and in vitro methods (fluorescence vital staining, MTT-assay). As a result, the composite scaffold showed good in vitro biocompatibility with partly open pore structure and the expected chemistry. First mechanical testing results indicate sufficient mechanical stability to support future in vivo applications. PMID:27287121

  15. Composite ECM-alginate microfibers produced by microfluidics as scaffolds with biomineralization potential.

    PubMed

    Angelozzi, Marco; Miotto, Martina; Penolazzi, Letizia; Mazzitelli, Stefania; Keane, Timothy; Badylak, Stephen F; Piva, Roberta; Nastruzzi, Claudio

    2015-11-01

    A novel approach to produce artificial bone composites (microfibers) with distinctive features mimicking natural tissue was investigated. Currently proposed inorganic materials (e.g. apatite matrixes) lack self-assembly and thereby limit interactions between cells and the material. The present work investigates the feasibility of creating "bio-inspired materials" specifically designed to overcome certain limitations inherent to current biomaterials. We examined the dimensions, morphology, and constitutive features of a composite hydrogel which combined an alginate based microfiber with a gelatin solution or a particulate form of urinary bladder matrix (UBM). The effectiveness of the composite microfibers to induce and modulate osteoblastic differentiation in three-dimensional (3D) scaffolds without altering the viability and morphological characteristics of the cells was investigated. The present study describes a novel alginate microfiber production method with the use of microfluidics. The microfluidic procedure allowed for precise tuning of microfibers which resulted in enhanced viability and function of embedded cells. PMID:26249575

  16. Demagnetization Treatment of Remanent Composite Microspheres Studied by Alternating Current Susceptibility Measurements

    PubMed Central

    van Berkum, Susanne; Erné, Ben H.

    2013-01-01

    The magnetic remanence of silica microspheres with a low concentration of embedded cobalt ferrite nanoparticles is studied after demagnetization and remagnetization treatments. When the microspheres are dispersed in a liquid, alternating current (AC) magnetic susceptibility spectra reveal a constant characteristic frequency, corresponding to the rotational diffusion of the microparticles; this depends only on particle size and liquid viscosity, making the particles suitable as a rheological probe and indicating that interactions between the microspheres are weak. On the macroscopic scale, a sample with the dry microparticles is magnetically remanent after treatment in a saturating field, and after a demagnetization treatment, the remanence goes down to zero. The AC susceptibility of a liquid dispersion, however, characterizes the remanence on the scale of the individual microparticles, which does not become zero after demagnetization. The reason is that an individual microparticle contains only a relatively small number of magnetic units, so that even if they can be reoriented magnetically at random, the average vector sum of the nanoparticle dipoles is not negligible on the scale of the microparticle. In contrast, on the macroscopic scale, the demagnetization procedure randomizes the orientations of a macroscopic number of magnetic units, resulting in a remanent magnetization that is negligible compared to the saturation magnetization of the entire sample. PMID:24009021

  17. Demagnetization treatment of remanent composite microspheres studied by alternating current susceptibility measurements.

    PubMed

    van Berkum, Susanne; Erné, Ben H

    2013-01-01

    The magnetic remanence of silica microspheres with a low concentration of embedded cobalt ferrite nanoparticles is studied after demagnetization and remagnetization treatments. When the microspheres are dispersed in a liquid, alternating current (AC) magnetic susceptibility spectra reveal a constant characteristic frequency, corresponding to the rotational diffusion of the microparticles; this depends only on particle size and liquid viscosity, making the particles suitable as a rheological probe and indicating that interactions between the microspheres are weak. On the macroscopic scale, a sample with the dry microparticles is magnetically remanent after treatment in a saturating field, and after a demagnetization treatment, the remanence goes down to zero. The AC susceptibility of a liquid dispersion, however, characterizes the remanence on the scale of the individual microparticles, which does not become zero after demagnetization. The reason is that an individual microparticle contains only a relatively small number of magnetic units, so that even if they can be reoriented magnetically at random, the average vector sum of the nanoparticle dipoles is not negligible on the scale of the microparticle. In contrast, on the macroscopic scale, the demagnetization procedure randomizes the orientations of a macroscopic number of magnetic units, resulting in a remanent magnetization that is negligible compared to the saturation magnetization of the entire sample. PMID:24009021

  18. Enhanced blue light shielding property of light-diffusion polycarbonate composites by CeO2-coated silicate microspheres

    NASA Astrophysics Data System (ADS)

    Zhao, Yu; Shi, Liyi; Tang, Anjie; Song, Na; Tang, Shengfu; Ding, Peng

    2015-07-01

    The CeO2 coated silicate microspheres (SMSs) core-shell particles (SMS-CeO2) were synthesized for enhancing blue light shielding property of polycarbonate (PC) composites. The structure analysis showed that CeO2 particles were homogenously coated on SMS by Ce-O-Si bonds. The optical analysis indicated that the transmittance of PC/SMS-CeO2 composites were enhanced to 63.2% from 42.9% for PC/SMS/CeO2 composites when 0.6 wt.% fillers were loaded, while there was no obvious influence on the haze of the composites. UV-Vis analysis showed that the absorbance at 450-nm wavelength of blue-light increased from 24% of PC/SMS to 50% of PC/SMS-CeO2 composites, while the absorbance at 650-nm wavelength of red-light was unchanged. These results indicated that the PC/SMS-CeO2 composites had blue light shielding property and better performance on transmitting other visible lights.

  19. Cytocompatibility of a conductive nanofibrous carbon nanotube/poly (L-Lactic acid) composite scaffold intended for nerve tissue engineering

    PubMed Central

    Kabiri, Mahboubeh; Oraee-Yazdani, Saeed; Dodel, Masumeh; Hanaee-Ahvaz, Hana; Soudi, Sara; Seyedjafari, Ehsan; Salehi, Mohammad; Soleimani, Masoud

    2015-01-01

    The purpose of this study was to fabricate a conductive aligned nanofibrous substrate and evaluate its suitability and cytocompatibility with neural cells for nerve tissue engineering purposes. In order to reach these goals, we first used electrospinning to fabricate single-walled carbon-nanotube (SWCNT) incorporated poly(L-lactic acid) (PLLA) nanofibrous scaffolds and then assessed its cytocompatibility with olfactory ensheathing glial cells (OEC). The plasma treated scaffolds were characterized using scanning electron microscopy and water contact angle. OECs were isolated from olfactory bulb of GFP Sprague-Dawley rats and characterized using OEC specific markers via immunocytochemistry and flow cytometery. The cytocompatibility of the conductive aligned nano-featured scaffold was assessed using microscopy and MTT assay. We indicate that doping of PLLA polymer with SWCNT can augment the aligned nanosized substrate with conductivity, making it favorable for nerve tissue engineering. Our results demonstrated that SWCNT/PLLA composite scaffold promote the adhesion, growth, survival and proliferation of OEC. Regarding the ideal physical, topographical and electrical properties of the scaffold and the neurotrophic and migratory features of the OECs, we suggest this scaffold and the cell/scaffold construct as a promising platform for cell delivery to neural defects in nerve tissue engineering approaches. PMID:26600751

  20. Fabrication, characterization, and biocompatibility of single-walled carbon nanotube-reinforced alginate composite scaffolds manufactured using freeform fabrication technique.

    PubMed

    Yildirim, Eda D; Yin, Xi; Nair, Kalyani; Sun, Wei

    2008-11-01

    Composite polymeric scaffolds from alginate and single-walled carbon nanotube (SWCNT) were produced using a freeform fabrication technique. The scaffolds were characterized for their structural, mechanical, and biological properties by scanning electron microscopy, Raman spectroscopy, tensile testing, and cell-scaffold interaction study. Three-dimensional hybrid alginate/SWCNT tissue scaffolds were fabricated in a multinozzle biopolymer deposition system, which makes possible to disperse and align SWCNTs in the alginate matrix. The structure of the resultant scaffolds was significantly altered due to SWCNT reinforcement, which was confirmed by Raman spectroscopy. Microtensile testing presented a reinforcement effect of SWCNT to the mechanical strength of the alginate struts. Ogden constitutive modeling was utilized to predict the stress-strain relationship of the alginate scaffold, which compared well with the experimental data. Cellular study by rat heart endothelial cell showed that the SWCNT incorporated in the alginate structure improved cell adhesion and proliferation. Our study suggests that hybrid alginate/SWCNT scaffolds are a promising biomaterial for tissue engineering applications. PMID:18506813

  1. Optimization of composition, structure and mechanical strength of bioactive 3-D glass-ceramic scaffolds for bone substitution.

    PubMed

    Baino, Francesco; Ferraris, Monica; Bretcanu, Oana; Verné, Enrica; Vitale-Brovarone, Chiara

    2013-03-01

    Fabrication of 3-D highly porous, bioactive, and mechanically competent scaffolds represents a significant challenge of bone tissue engineering. In this work, Bioglass®-derived glass-ceramic scaffolds actually fulfilling this complex set of requirements were successfully produced through the sponge replication method. Scaffold processing parameters and sintering treatment were carefully designed in order to obtain final porous bodies with pore content (porosity above 70 %vol), trabecular architecture and mechanical properties (compressive strength up to 3 MPa) analogous to those of the cancellous bone. Influence of the Bioglass® particles size on the structural and mechanical features of the sintered scaffolds was considered and discussed. Relationship between porosity and mechanical strength was investigated and modeled. Three-dimensional architecture, porosity, mechanical strength and in vitro bioactivity of the optimized Bioglass®-derived scaffolds were also compared to those of CEL2-based glass-ceramic scaffolds (CEL2 is an experimental bioactive glass originally developed by the authors at Politecnico di Torino) fabricated by the same processing technique, in an attempt at understanding the role of different bioactive glass composition on the major features of scaffolds prepared by the same method. PMID:22207602

  2. Evaluation of the novel three-dimensional porous poly (L-lactic acid)/nano-hydroxyapatite composite scaffold.

    PubMed

    Huang, Jianghong; Xiong, Jianyi; Liu, Jianquan; Zhu, Weimin; Chen, Jielin; Duan, Li; Zhang, Jufeng; Wang, Daping

    2015-01-01

    To determine the optimal ratio of nano-hydroxyapatite (n-HA) to polylactic acid (PLLA) in the novel three-dimensional porous PLLA/n-HA composite scaffolds, low-temperature rapid prototyping technology was employed to fabricate the composite materials with different n-HA contents. Mechanical properties and degradation behaviors of the composites were examined, and the scaffold microstructure and n-HA dispersion were observed by scanning electron microscope (SEM). Mechanical tests demonstrated that the tensile strength of the composite material gradually decreased with an increase in n-HA content. When the n-HA content reached 20 wt%, the bending strength of the composite material peaked at 138.5 MPa. SEM images demonstrated that the optimal content of n-HA was 20 wt% as the largest interconnected pore size that can be seen, with a porosity as high as 80%. In vitro degradation experiments demonstrated that the pH value of the material containing solution gradually decreased in a time-dependent manner, with a simultaneous weakening of the mechanical properties. In vitro study using rat osteoblast cells showed that the composite scaffolds were biocompatible; the 20 wt% n-HA scaffold offered particular improvement to rat osteoblast cell adhesion and proliferation compared to other compositions. It was therefore concluded that 20 wt% n-HA is the optimal nano-hydroxyapatite (n-HA) to polylactic acid (PLLA) ratio, with promise for bone tissue engineering. PMID:26405972

  3. Composite scaffolds for osteochondral repair obtained by combination of additive manufacturing, leaching processes and hMSC-CM functionalization.

    PubMed

    Díaz Lantada, Andrés; Alarcón Iniesta, Hernán; García-Ruíz, Josefa Predestinación

    2016-02-01

    Articular repair is a relevant and challenging area for the emerging fields of tissue engineering and biofabrication. The need of significant gradients of properties, for the promotion of osteochondral repair, has led to the development of several families of composite biomaterials and scaffolds, using different effective approaches, although a perfect solution has not yet been found. In this study we present the design, modeling, rapid manufacturing and in vitro testing of a composite scaffold aimed at osteochondral repair. The presented composite scaffold stands out for having a functional gradient of density and stiffness in the bony phase, obtained in titanium by means of computer-aided design combined with additive manufacture using selective laser sintering. The chondral phase is obtained by sugar leaching, using a PDMS matrix and sugar as porogen, and is joined to the bony phase during the polymerization of PDMS, therefore avoiding the use of supporting adhesives or additional intermediate layers. The mechanical performance of the construct is biomimetic and the stiffness values of the bony and chondral phases can be tuned to the desired applications, by means of controlled modifications of different parameters. A human mesenchymal stem cell (h-MSC) conditioned medium (CM) is used for improving scaffold response. Cell culture results provide relevant information regarding the viability of the composite scaffolds used. PMID:26652367

  4. The role of nanostructured mesoporous silicon in discriminating in vitro calcification for electrospun composite tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Fan, Dongmei; Akkaraju, Giridhar R.; Couch, Ernest F.; CanhamCurrent Address, Intrinsiq Materials Ltd, Geraldine Road, Malvern Wr14 3SZ Uk, Leigh T.; Coffer, Jeffery L.

    2011-02-01

    The impact of mesoporous silicon (PSi) particles-embedded either on the surface, or totally encapsulated within electrospun poly (ε-caprolactone) (PCL) fibers-on its properties as a tissue engineering scaffold is assessed. Our findings suggest that the resorbable porous silicon component can sensitively accelerate the necessary calcification process in such composites. Calcium phosphate deposition on the scaffolds was measured via in vitro calcification assays both at acellular and cellular levels. Extensive attachment of fibroblasts, human adult mesenchymal stem cells, and mouse stromal cells to the scaffold were observed. Complementary cell differentiation assays and ultrastructural measurements were also carried out; the levels of alkaline phosphatase expression, a specific biomarker for mesenchymal stem cell differentiation, show that the scaffolds have the ability to mediate such processes, and that the location of the Si plays a key role in levels of expression.

  5. Composite Scaffolds Containing Silk Fibroin, Gelatin, and Hydroxyapatite for Bone Tissue Regeneration and 3D Cell Culturing

    PubMed Central

    Moisenovich, M. M.; Arkhipova, A. Yu.; Orlova, A. A.; Drutskaya, M. S; Volkova, S. V.; Zacharov, S. E.; Agapov, I. I.; Kirpichnikov, M. P.

    2014-01-01

    Three-dimensional (3D) silk fibroin scaffolds were modified with one of the major bone tissue derivatives (nano-hydroxyapatite) and/or a collagen derivative (gelatin). Adhesion and proliferation of mouse embryonic fibroblasts (MEF) within the scaffold were increased after modification with either nano-hydroxyapatite or gelatin. However, a significant increase in MEF adhesion and proliferation was observed when both additives were introduced into the scaffold. Such modified composite scaffolds provide a new and better platform to study wound healing, bone and other tissue regeneration, as well as artificial organ bioengineering. This system can further be applied to establish experimental models to study cell-substrate interactions, cell migration and other complex processes, which may be difficult to address using the conventional two-dimensional culture systems. PMID:24772332

  6. Mesoporous bioactive glass doped-poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) composite scaffolds with 3-dimensionally hierarchical pore networks for bone regeneration.

    PubMed

    Yang, Shengbing; Wang, Jing; Tang, Liangji; Ao, Haiyong; Tan, Honglue; Tang, Tingting; Liu, Changsheng

    2014-04-01

    Scaffolds play a critical role in bone tissue engineering. Composite scaffolds made of biodegradable polymers and bioactive inorganic compounds have demonstrated superior properties in bone defect repair. In this study, highly bioactive, resorbable poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx)-based scaffolds were prepared using combinational 3-dimensional (3D) printing and surface-doping protocol. Structural and morphological characterization of the composite scaffolds demonstrated the homogenous surface-coating of mesoporous bioactive glass (MBG) throughout their porous framework. These hierarchical scaffolds showed bioactivity superior to that of scaffolds made of pure PHBHHx. MBG coating appeared to provide a better environment for human mesenchymal stem cells (hMSCs) attachment, activity, and osteogenic differentiation. Our study indicates that MBG-coated PHBHHx (PHBM) scaffolds may be excellent candidates for use in bone tissue engineering. PMID:24441182

  7. Preparation and characterization of new nano-composite scaffolds loaded with vascular stents.

    PubMed

    Xu, Hongzhen; Su, Jiansheng; Sun, Jun; Ren, Tianbin

    2012-01-01

    In this study, vascular stents were fabricated from poly (lactide-ɛ-caprolactone)/collagen/nano-hydroxyapatite (PLCL/Col/nHA) by electrospinning, and the surface morphology and breaking strength were observed or measured through scanning electron microscopy and tensile tests. The anti-clotting properties of stents were evaluated for anticoagulation surfaces modified by the electrostatic layer-by-layer self-assembly technique. In addition, nano-composite scaffolds of poly (lactic-co-glycolic acid)/polycaprolactone/nano-hydroxyapatite (PLGA/PCL/nHA) loaded with the vascular stents were prepared by thermoforming-particle leaching and their basic performance and osteogenesis were tested in vitro and in vivo. The results show that the PLCL/Col/nHA stents and PLGA/PCL/nHA nano-composite scaffolds had good surface structures, mechanical properties, biocompatibility and could guide bone regeneration. These may provide a new way to build vascularized-tissue engineered bone to repair large bone defects in bone tissue engineering. PMID:22489156

  8. Fusion microsphere targets

    SciTech Connect

    Koo, J.C.

    1980-07-28

    It was shown that a microsphere within the structure limitations is hydrodynamically stable. To insure its perfect formation, the initial chemical compositions must have a blowing capability, more important, the resultant liquid compositions must also have sufficient surface tension and low viscosity.

  9. Bioactive glass-based composites for the production of dense sintered bodies and porous scaffolds.

    PubMed

    Bellucci, D; Sola, A; Cannillo, V

    2013-05-01

    Recently several attempts have been made to combine calcium phosphates, such as β-tricalcium phosphate (β-TCP) and, most of all, hydroxyapatite (HA), with bioactive glasses of different composition, in order to develop composites with improved biological and mechanical performance. Unfortunately, the production of such systems usually implies a high-temperature treatment (up to 1300 °C), which may result in several drawbacks, including crystallization of the original glass, decomposition of the calcium phosphate phase and/or reactions between the constituent phases, with non-trivial consequences in terms of microstructure, bioactivity and mechanical properties of the final samples. In the present contribution, novel binary composites have been obtained by sintering a bioactive glass, characterized by a low tendency to crystallize, with the addition of HA or β-TCP as the second phase. In particular, the composites have been treated at a relatively low temperature (818 °C and 830 °C, depending on the sample), thus preserving the amorphous structure of the glass and minimizing the interaction between the constituent phases. The effects of the glass composition, calcium phosphate nature and processing conditions on the composite microstructure, mechanical properties and in vitro bioactivity have been systematically discussed. To conclude, a feasibility study to obtain scaffolds for bone tissue regeneration has been proposed. PMID:23498242

  10. Novel polyvinyl alcohol-bioglass 45S5 based composite nanofibrous membranes as bone scaffolds.

    PubMed

    Shankhwar, Nisha; Kumar, Manishekhar; Mandal, Biman B; Srinivasan, A

    2016-12-01

    Composite nanofibrous membranes based on sol-gel derived 45SiO2 24.5CaO 24.5 Na2O 6 P2O5 (bioglass, BG) and 43SiO2 24.5CaO 24.5 Na2O 6 P2O5 2Fe2O3 (magnetic bioglass, MBG) blended with polyvinyl alcohol (PVA) have been electrospun. These low cost membranes were mostly amorphous in structure with minor crystalline (sodium calcium phosphate) precipitates. All membranes were biodegradable. Among these, the composites exhibited higher tensile strength, better proliferation of human osteosarcoma MG63 cells and higher alkaline phosphatase enzyme activity than the bare PVA membrane, indicating their potential in bone tissue engineering. The magnetic PVA-MBG scaffold was also found to be a promising candidate for magnetic hyperthermia application. PMID:27612814