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Sample records for hydroxyapatite scaffolds fabricated

  1. Accurate Fabrication of Hydroxyapatite Bone Models with Porous Scaffold Structures by Using Stereolithography

    NASA Astrophysics Data System (ADS)

    Maeda, Chiaki; Tasaki, Satoko; Kirihara, Soshu

    2011-05-01

    Computer graphic models of bioscaffolds with four-coordinate lattice structures of solid rods in artificial bones were designed by using a computer aided design. The scaffold models composed of acryl resin with hydroxyapatite particles at 45vol. % were fabricated by using stereolithography of a computer aided manufacturing. After dewaxing and sintering heat treatment processes, the ceramics scaffold models with four-coordinate lattices and fine hydroxyapatite microstructures were obtained successfully. By using a computer aided analysis, it was found that bio-fluids could flow extensively inside the sintered scaffolds. This result shows that the lattice structures will realize appropriate bio-fluid circulations and promote regenerations of new bones.

  2. Biological advantages of porous hydroxyapatite scaffold made by solid freeform fabrication for bone tissue regeneration.

    PubMed

    Kwon, Byeong-Ju; Kim, Jungsung; Kim, Yong Hwa; Lee, Mi Hee; Baek, Hyun Sook; Lee, Dae Hyung; Kim, Hye-Lee; Seo, Hyok Jin; Lee, Min Hyeon; Kwon, Soon-Young; Koo, Min-Ah; Park, Jong-Chul

    2013-07-01

    Presently, commercially available porous bone substitutes are manufactured by the sacrificial template method, direct foaming method, and polymer replication method (PRM). However, current manufacturing methods provide only the simplest form of the bone scaffold and cannot easily control pore size. Recent developments in medical imaging technology, computer-aided design, and solid freeform fabrication (SFF), have made it possible to accurately produce porous synthetic bone scaffolds to fit the defected bone shape. Porous scaffolds were fabricated by SFF and PRM for a comparison of physical and mechanical properties of scaffold. The suggested three-dimensional model has interconnected cubic pores of 500 μm and its calculated porosity is 25%. Whereas hydroxyapatite scaffolds fabricated by SFF had connective macropores, those by PRM formed a closed pore external surface with internally interconnected pores. SFF was supposed to be a proper method for fabricating an interconnected macroporous network. Biocompatibility was confirmed by testing the cytotoxicity, hemolysis, irritation, sensitization, and implantation. In summary, the aim was to verify the safety and efficacy of the scaffolds by biomechanical and biological tests with the hope that this research could promote the feasibility of using the scaffolds as a bone substitute.

  3. Silk as a biocohesive sacrificial binder in the fabrication of hydroxyapatite load bearing scaffolds.

    PubMed

    McNamara, Stephanie L; Rnjak-Kovacina, Jelena; Schmidt, Daniel F; Lo, Tim J; Kaplan, David L

    2014-08-01

    Limitations of current clinical methods for bone repair continue to fuel the demand for a high strength, bioactive bone replacement material. Recent attempts to produce porous scaffolds for bone regeneration have been limited by the intrinsic weakness associated with high porosity materials. In this study, ceramic scaffold fabrication techniques for potential use in load-bearing bone repairs have been developed using naturally derived silk from Bombyx mori. Silk was first employed for ceramic grain consolidation during green body formation, and later as a sacrificial polymer to impart porosity during sintering. These techniques allowed preparation of hydroxyapatite (HA) scaffolds that exhibited a wide range of mechanical and porosity profiles, with some displaying unusually high compressive strength up to 152.4 ± 9.1 MPa. Results showed that the scaffolds exhibited a wide range of compressive strengths and moduli (8.7 ± 2.7 MPa to 152.4 ± 9.1 MPa and 0.3 ± 0.1 GPa to 8.6 ± 0.3 GPa) with total porosities of up to 62.9 ± 2.7% depending on the parameters used for fabrication. Moreover, HA-silk scaffolds could be molded into large, complex shapes, and further machined post-sinter to generate specific three-dimensional geometries. Scaffolds supported bone marrow-derived mesenchymal stem cell attachment and proliferation, with no signs of cytotoxicity. Therefore, silk-fabricated HA scaffolds show promise for load bearing bone repair and regeneration needs.

  4. Silk as a biocohesive sacrificial binder in the fabrication of hydroxyapatite load bearing scaffolds

    PubMed Central

    McNamara, Stephanie L.; Rnjak-Kovacina, Jelena; Schmidt, Daniel; Lo, Tim J.; Kaplan, David L.

    2014-01-01

    Limitations of current clinical methods for bone repair continue to fuel the demand for a high strength, bioactive bone replacement material. Recent attempts to produce porous scaffolds for bone regeneration have been limited by the intrinsic weakness associated with high porosity materials. In this study, ceramic scaffold fabrication techniques for potential use in load-bearing bone repairs have been developed using naturally derived silk from Bombyx mori. Silk was first employed for ceramic grain consolidation during green body formation, and later as a sacrificial polymer to impart porosity during sintering. These techniques allowed preparation of hydroxyapatite (HA) scaffolds that exhibited a wide range of mechanical and porosity profiles, with some displaying unusually high compressive strength up to 152.4 ± 9.1 MPa. Results showed that the scaffolds exhibited a wide range of compressive strengths and moduli (8.7 ± 2.7 MPa to 152.4 ± 9.1 MPa and 0.3 ± 0.1 GPa to 8.6 ± 0.3 GPa) with total porosities of up to 62.9 ± 2.7% depending on the parameters used for fabrication. Moreover, HA-silk scaffolds could be molded into large, complex shapes, and further machined post-sinter to generate specific three-dimensional geometries. Scaffolds supported bone marrow-derived mesenchymal stem cell attachment and proliferation, with no signs of cytotoxicity. Therefore, silk-fabricated HA scaffolds show promise for load bearing bone repair and regeneration needs. PMID:24881027

  5. In-vivo behavior of Si-hydroxyapatite/polycaprolactone/DMB scaffolds fabricated by 3D printing.

    PubMed

    Meseguer-Olmo, Luis; Vicente-Ortega, Vicente; Alcaraz-Baños, Miguel; Calvo-Guirado, José Luis; Vallet-Regí, María; Arcos, Daniel; Baeza, Alejandro

    2013-07-01

    Scaffolds made of polycaprolactone and nanocrystalline silicon-substituted hydroxyapatite have been fabricated by 3D printing rapid prototyping technique. To asses that the scaffolds fulfill the requirements to be considered for bone grafting applications, they were implanted in New Zealand rabbits. Histological and radiological studies have demonstrated that the scaffolds implanted in bone exhibited an excellent osteointegration without the interposition of fibrous tissue between bone and implants and without immune response after 4 months of implantation. In addition, we have evaluated the possibility of improving the scaffolds efficiency by incorporating demineralized bone matrix during the preparation by 3D printing. When demineralized bone matrix (DBM) is incorporated, the efficacy of the scaffolds is enhanced, as new bone formation occurs not only in the peripheral portions of the scaffolds but also within its pores after 4 months of implantation. This enhanced performance can be explained in terms of the osteoinductive properties of the DBM in the scaffolds, which have been assessed through the new bone tissue formation when the scaffolds are ectopically implanted.

  6. Fabrication of hybrid nanocomposite scaffolds by incorporating ligand-free hydroxyapatite nanoparticles into biodegradable polymer scaffolds and release studies.

    PubMed

    Farkas, Balazs; Rodio, Marina; Romano, Ilaria; Diaspro, Alberto; Intartaglia, Romuald; Beke, Szabolcs

    2015-01-01

    We report on the optical fabrication approach of preparing free-standing composite thin films of hydroxyapatite (HA) and biodegradable polymers by combining pulsed laser ablation in liquid and mask-projection excimer laser stereolithography (MPExSL). Ligand-free HA nanoparticles were prepared by ultrafast laser ablation of a HA target in a solvent, and then the nanoparticles were dispersed into the liquid polymer resin prior to the photocuring process using MPExSL. The resin is poly(propylene fumarate) (PPF), a photo-polymerizable, biodegradable material. The polymer is blended with diethyl fumarate in 7:3 w/w to adjust the resin viscosity. The evaluation of the structural and mechanical properties of the fabricated hybrid thin film was performed by means of SEM and nanoindentation, respectively, while the chemical and degradation studies were conducted through thermogravimetric analysis, and FTIR. The photocuring efficiency was found to be dependent on the nanoparticle concentration. The MPExSL process yielded PPF thin films with a stable and homogenous dispersion of the embedded HA nanoparticles. Here, it was not possible to tune the stiffness and hardness of the scaffolds by varying the laser parameters, although this was observed for regular PPF scaffolds. Finally, the gradual release of the hydroxyapatite nanoparticles over thin film biodegradation is reported. PMID:26734513

  7. Fabrication of hybrid nanocomposite scaffolds by incorporating ligand-free hydroxyapatite nanoparticles into biodegradable polymer scaffolds and release studies

    PubMed Central

    Farkas, Balazs; Rodio, Marina; Romano, Ilaria; Diaspro, Alberto; Intartaglia, Romuald

    2015-01-01

    Summary We report on the optical fabrication approach of preparing free-standing composite thin films of hydroxyapatite (HA) and biodegradable polymers by combining pulsed laser ablation in liquid and mask-projection excimer laser stereolithography (MPExSL). Ligand-free HA nanoparticles were prepared by ultrafast laser ablation of a HA target in a solvent, and then the nanoparticles were dispersed into the liquid polymer resin prior to the photocuring process using MPExSL. The resin is poly(propylene fumarate) (PPF), a photo-polymerizable, biodegradable material. The polymer is blended with diethyl fumarate in 7:3 w/w to adjust the resin viscosity. The evaluation of the structural and mechanical properties of the fabricated hybrid thin film was performed by means of SEM and nanoindentation, respectively, while the chemical and degradation studies were conducted through thermogravimetric analysis, and FTIR. The photocuring efficiency was found to be dependent on the nanoparticle concentration. The MPExSL process yielded PPF thin films with a stable and homogenous dispersion of the embedded HA nanoparticles. Here, it was not possible to tune the stiffness and hardness of the scaffolds by varying the laser parameters, although this was observed for regular PPF scaffolds. Finally, the gradual release of the hydroxyapatite nanoparticles over thin film biodegradation is reported. PMID:26734513

  8. Fabrication and Dynamic Mechanical Analysis of Hydroxyapatite Nanoparticle/Gelatin Porous Scaffolds

    NASA Astrophysics Data System (ADS)

    Ghossein, Hicham

    The application of engineered biomaterial scaffolds for hard tissue repair critically depends on the scaffold's internal architecture at various length scales. The pore size, shape, surface morphology, and pore connectivity are among the most important factors that affect the scaffold's mechanical properties and biointegration. Reported in this thesis are the results of the investigation of porous constructs fabricated by a freeze-drying process from synthetic nanosized hydroxyapatite / gelatin (nanoHA/Gel) dispersions with different nanoHA/Gel ratios (nanoHA loading was varied from 0 to 50 % by weight). The fabricated scaffolds had porosity up to 90% with pore size in the range of 100 - 500 im, and good distribution of HA nanoparticles within the gelatin matrix. Such porosity is considered to be close to optimal to promote a good cell adhesion in the potential applications of prepared constructs. The fabricated scaffolds have been investigated using X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Dynamic Mechanical Analysis (DMA). Dynamic mechanical analysis of as-fabricated scaffolds revealed that the scaffolds achieved maximum bending and tensile moduli up to 1.28 GPa and 1.5 GPa, respectively, when nanoHA loading was around 30 % by weight. The bending modulus increases by a factor of 1.6, while the Tension modulus increased by a factor of 0.8 after the cross-linking of polymer. Higher nanoHA loading above 50 % by weight results in bending modulus of about 700 MPa and Tension modulus of about 200 MPa only. However, the cross-linking still enhanced the bending up to 1 GPa while it did not affect much the Tension modulus in 50% nanoHA/gelatin constructs. It has been shown that the cross-linking with glutaraldehyde solution improves the morphological structure of the scaffolds, while there was no apparent effect of the cross-linking on the chemical changes in both organic and inorganic content during the processing. The results of this

  9. Fabrication and characterization of novel nano-biocomposite scaffold of chitosan-gelatin-alginate-hydroxyapatite for bone tissue engineering.

    PubMed

    Sharma, Chhavi; Dinda, Amit Kumar; Potdar, Pravin D; Chou, Chia-Fu; Mishra, Narayan Chandra

    2016-07-01

    A novel nano-biocomposite scaffold was fabricated in bead form by applying simple foaming method, using a combination of natural polymers-chitosan, gelatin, alginate and a bioceramic-nano-hydroxyapatite (nHAp). This approach of combining nHAp with natural polymers to fabricate the composite scaffold, can provide good mechanical strength and biological property mimicking natural bone. Environmental scanning electron microscopy (ESEM) images of the nano-biocomposite scaffold revealed the presence of interconnected pores, mostly spread over the whole surface of the scaffold. The nHAp particulates have covered the surface of the composite matrix and made the surface of the scaffold rougher. The scaffold has a porosity of 82% with a mean pore size of 112±19.0μm. Swelling and degradation studies of the scaffold showed that the scaffold possesses excellent properties of hydrophilicity and biodegradability. Short term mechanical testing of the scaffold does not reveal any rupturing after agitation under physiological conditions, which is an indicative of good mechanical stability of the scaffold. In vitro cell culture studies by seeding osteoblast cells over the composite scaffold showed good cell viability, proliferation rate, adhesion and maintenance of osteoblastic phenotype as indicated by MTT assay, ESEM of cell-scaffold construct, histological staining and gene expression studies, respectively. Thus, it could be stated that the nano-biocomposite scaffold of chitosan-gelatin-alginate-nHAp has the paramount importance for applications in bone tissue-engineering in future regenerative therapies.

  10. Fabrication of 3D Scaffolds with Nano-Hydroxyapatite for Improving the Preosteoblast Cell-Biological Performance.

    PubMed

    Roh, Hee-Sang; Myung, Sung-Woon; Jung, Sang-Chul; Kim, Byung-Hoon

    2015-08-01

    Three-dimensional (3D) scaffolds fabricated by rapid prototyping techniques have many merits for tissue engineering applications, due to its controllable properties such as porosity, pore size and structural shape. Nonetheless, low cell seeding efficiency remains drawback. In this study, poly-caprolactone (PCL) composite 3D extruded scaffolds were modified with nano hydroxyapatite (n-HAp). PCL/n-HAp 3D scaffold surface was treated with oxygen plasma to improve the preosteoblast cell seeding efficiency and proliferation. The results indicate that oxygen plasma is useful technique to improve the cell affinity.

  11. MC3T3-E1 osteoblast attachment and proliferation on porous hydroxyapatite scaffolds fabricated with nanophase powder.

    PubMed

    Smith, Ian O; McCabe, Laura R; Baumann, Melissa J

    2006-01-01

    Porous bone tissue engineering scaffolds were fabricated using both nano hydroxyapatite (nano HA) powder (20 nm average particle size) and micro HA powder (10 microm average particle size), resulting in sintered scaffolds of 59 vol% porosity and 8.6 +/- 1.9 microm average grain size and 72 vol% porosity and 588 +/- 55nm average grain size, respectively. Scanning electron microscopy was used to measure both the grain size and pore size. MC3T3-E1 osteoblast (OB) attachment and proliferation on both nano HA and micro HA porous scaffolds were quantified. As expected, OB cell number was greater on nano HA scaffolds compared with similarly processed micro HA scaffolds 5 days after seeding, while OB attachment did not appear greater on the nano HA scaffolds (p < 0.05).

  12. Oxygen and nitrogen plasma etching of three-dimensional hydroxyapatite/chitosan scaffolds fabricated by additive manufacturing

    NASA Astrophysics Data System (ADS)

    Myung, Sung-Woon; Kim, Byung-Hoon

    2016-01-01

    Three-dimensional (3D) chitosan and hydroxyapatite (HAp)/chitosan (CH) scaffolds were fabricated by additive manufacturing, then their surfaces were etched with oxygen (O2) and nitrogen (N2) plasma. O2 and N2 plasma etching was performed to increase surface properties such as hydrophilicity, roughness, and surface chemistry on the scaffolds. After etching, hydroxyapatite was exposed on the surface of 3D HAp/CH scaffolds. The surface morphology and chemical properties were characterized by contact angle measurement, scanning electron microscopy, X-ray diffraction, and attenuated total reflection Fourier infrared spectroscopy. The cell viability of 3D chitosan scaffolds was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The differentiation of preosteoblast cells was evaluated by alkaline phosphatase assay. The cell viability was improved by O2 and N2 plasma etching of 3D chitosan scaffolds. The present fabrication process for 3D scaffolds might be applied to a potential tool for preparing biocompatible scaffolds.

  13. Microwave-assisted fabrication of chitosan-hydroxyapatite superporous hydrogel composites as bone scaffolds.

    PubMed

    Beşkardeş, Işıl Gerçek; Demirtaş, Tuğrul Tolga; Durukan, Müge Dağlı; Gümüşderelioğlu, Menemşe

    2015-11-01

    In this study, a novel scaffold fabrication method was developed by combining microwave irradiation and gas foaming. Chitosan superporous hydrogels (SPHs) and chitosan-hydroxyapatite (HA) superporous hydrogel composites (SPHCs) were prepared by using this method in the presence of crosslinking agent, glyoxal, and a gas-blowing agent, NaHCO3. In order to examine the effect of HA on composite structure and cellular behaviour, two types of HA particles, i.e. spherical beads in 45-80 µm diameter and powder form, were used. While rapid heating with microwave irradiation enhances gas blowing, pH increment, which is accelerated by NaHCO3 decomposition, provides better crosslinking. Thus, interconnected and well-established macroporous hydrogels/hydrogel composites were produced easily and rapidly (~1 min). Cell culture studies, which were carried out under static and dynamic conditions with MC3T3-E1 pre-osteoblastic cells, indicated that chitosan-HA bead SPHCs supported cellular proliferation and osteoblastic differentiation better than chitosan SPHs and chitosan-HA powder SPHCs. In conclusion, simultaneous gas foaming and microwave crosslinking can be evaluated for the preparation of composite scaffolds which have superior properties for bone tissue engineering.

  14. Selective laser sintering fabrication of nano-hydroxyapatite/poly-ε-caprolactone scaffolds for bone tissue engineering applications

    PubMed Central

    Xia, Yan; Zhou, Panyu; Cheng, Xiaosong; Xie, Yang; Liang, Chong; Li, Chao; Xu, Shuogui

    2013-01-01

    The regeneration of functional tissue in osseous defects is a formidable challenge in orthopedic surgery. In the present study, a novel biomimetic composite scaffold, here called nano-hydroxyapatite (HA)/poly-ε-caprolactone (PCL) was fabricated using a selective laser sintering technique. The macrostructure, morphology, and mechanical strength of the scaffolds were characterized. Scanning electronic microscopy (SEM) showed that the nano-HA/PCL scaffolds exhibited predesigned, well-ordered macropores and interconnected micropores. The scaffolds have a range of porosity from 78.54% to 70.31%, and a corresponding compressive strength of 1.38 MPa to 3.17 MPa. Human bone marrow stromal cells were seeded onto the nano-HA/PCL or PCL scaffolds and cultured for 28 days in vitro. As indicated by the level of cell attachment and proliferation, the nano-HA/PCL showed excellent biocompatibility, comparable to that of PCL scaffolds. The hydrophilicity, mineralization, alkaline phosphatase activity, and Alizarin Red S staining indicated that the nano-HA/PCL scaffolds are more bioactive than the PCL scaffolds in vitro. Measurements of recombinant human bone morphogenetic protein-2 (rhBMP-2) release kinetics showed that after nano-HA was added, the material increased the rate of rhBMP-2 release. To investigate the in vivo biocompatibility and osteogenesis of the composite scaffolds, both nano-HA/PCL scaffolds and PCL scaffolds were implanted in rabbit femur defects for 3, 6, and 9 weeks. The wounds were studied radiographically and histologically. The in vivo results showed that both nano-HA/PCL composite scaffolds and PCL scaffolds exhibited good biocompatibility. However, the nano-HA/PCL scaffolds enhanced the efficiency of new bone formation more than PCL scaffolds and fulfilled all the basic requirements of bone tissue engineering scaffolds. Thus, they show large potential for use in orthopedic and reconstructive surgery. PMID:24204147

  15. Improved biocomposite development of poly(vinyl alcohol) and hydroxyapatite for tissue engineering scaffold fabrication using selective laser sintering.

    PubMed

    Wiria, Florencia Edith; Chua, Chee Kai; Leong, Kah Fai; Quah, Zai Yan; Chandrasekaran, Margam; Lee, Mun Wai

    2008-03-01

    In scaffold guided tissue engineering (TE), temporary three-dimensional scaffolds are essential to guide and support cell proliferation. Selective Laser Sintering (SLS) is studied for the development of such scaffolds by eliminating pore spatial control problems faced in conventional scaffolds fabrication methods. SLS offers good user control over the scaffold's microstructures by adjusting its main processing parameters, namely the laser power, scan speed and part bed temperature. This research focuses on the improvements in the fabrication of TE scaffolds using SLS with powder biomaterials, namely hydroxyapatite (HA) and poly(vinyl alcohol) (PVA). Grinding of as-received PVA powder to varying particle sizes and two methods of mixing are investigated as the preparation process to determine a better mixing method that would enhance the mixture homogeneity. Suitable sintering conditions for the improved biocomposite are then achieved by varying the important process parameters such as laser power, scan speed and part bed temperature.SLS fabricated samples are characterized using Fourier Transform Infrared Spectrometer (FTIR) and Scanning Electron Microscope (SEM). FTIR results show that the grinding and sintering processes neither compromise the chemical composition of the PVA nor cause undue degradation. Visual analysis of the grinding, powder mixing and sintering effect are carried out with SEM. The SEM observations show improvements in the sintering effects. The favorable outcome ascertains PVA/HA biocomposite as a suitable material to be processed by SLS for TE scaffolds. PMID:17665112

  16. Parameters optimization for the fabrication of phosphate glass/hydroxyapatite nanocomposite scaffold

    NASA Astrophysics Data System (ADS)

    Govindan, R.; Girija, E. K.

    2015-06-01

    Three-dimensional, highly porous, bioactive and biodegradable phosphate glass and nanohydroxyapatite (n-HA) composite scaffolds was fabricated by the polymer foam replication technique. Polyurethane foam (PU) and polyvinyl alcohol (PVA) were used as template and binder, respectively. Optimization of composition and sintering temperature is carried out for tissue engineering scaffold fabrication.

  17. Study the bonding mechanism of binders on hydroxyapatite surface and mechanical properties for 3DP fabrication bone scaffolds.

    PubMed

    Wei, Qinghua; Wang, Yanen; Li, Xinpei; Yang, Mingming; Chai, Weihong; Wang, Kai; zhang, Yingfeng

    2016-04-01

    In 3DP fabricating artificial bone scaffolds process, the interaction mechanism between binder and bioceramics power determines the microstructure and macro mechanical properties of Hydroxyapatite (HA) bone scaffold. In this study, we applied Molecular Dynamics (MD) methods to investigating the bonding mechanism and essence of binders on the HA crystallographic planes for 3DP fabrication bone scaffolds. The cohesive energy densities of binders and the binding energies, PCFs g(r), mechanical properties of binder/HA interaction models were analyzed through the MD simulation. Additionally, we prepared the HA bone scaffold specimens with different glues by 3DP additive manufacturing, and tested their mechanical properties by the electronic universal testing machine. The simulation results revealed that the relationship of the binding energies between binders and HA surface is consistent with the cohesive energy densities of binders, which is PAM/HA>PVA/HA>PVP/HA. The PCFs g(r) indicated that their interfacial interactions mainly attribute to the ionic bonds and hydrogen bonds which formed between the polar atoms, functional groups in binder polymer and the Ca, -OH in HA. The results of mechanical experiments verified the relationship of Young׳s modulus for three interaction models in simulation, which is PVA/HA>PAM/HA>PVP/HA. But the trend of compressive strength is PAM/HA>PVA/HA>PVP/HA, this is consistent with the binding energies of simulation. Therefore, the Young׳s modulus of bone scaffolds are limited by the Young׳s modulus of binders, and the compressive strength is mainly decided by the viscosity of binder. Finally, the major reasons for differences in mechanical properties between simulation and experiment were found, the space among HA pellets and the incomplete infiltration of glue were the main reasons influencing the mechanical properties of 3DP fabrication HA bone scaffolds. These results provide useful information in choosing binder for 3DP fabrication

  18. Fabrication of novel Si-doped hydroxyapatite/gelatine scaffolds by rapid prototyping for drug delivery and bone regeneration.

    PubMed

    Martínez-Vázquez, F J; Cabañas, M V; Paris, J L; Lozano, D; Vallet-Regí, M

    2015-03-01

    Porous 3-D scaffolds consisting of gelatine and Si-doped hydroxyapatite were fabricated at room temperature by rapid prototyping. Microscopic characterization revealed a highly homogeneous structure, showing the pre-designed porosity (macroporosity) and a lesser in-rod porosity (microporosity). The mechanical properties of such scaffolds are close to those of trabecular bone of the same density. The biological behavior of these hybrid scaffolds is greater than that of pure ceramic scaffolds without gelatine, increasing pre-osteoblastic MC3T3-E1 cell differentiation (matrix mineralization and gene expression). Since the fabrication process of these structures was carried out at mild conditions, an antibiotic (vancomycin) was incorporated in the slurry before the extrusion of the structures. The release profile of this antibiotic was measured in phosphate-buffered saline solution by high-performance liquid chromatography and was adjusted to a first-order release kinetics. Vancomycin released from the material was also shown to inhibit bacterial growth in vitro. The implications of these results for bone tissue engineering applications are discussed. PMID:25560614

  19. Hydroxyapatite-reinforced collagen tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Kane, Robert J.

    Scaffolds have been fabricated from a wide variety of materials and most have showed some success, either as bone graft substitutes or as tissue engineering scaffolds. However, all current scaffold compositions and architectures suffer from one or more flaws including poor mechanical properties, lack of biological response, nondegradability, or a scaffold architecture not conducive to osteointegration. Biomimetic approaches to scaffold design using the two main components of bone tissue, collagen and hydroxyapatite, resulted in scaffolds with superior biological properties but relatively poor mechanical properties and scaffold architecture. It was hypothesized that by optimizing scaffold composition and architecture, HA-collagen bone tissue engineering scaffolds could provide both an excellent biological response along with improved structural properties. The mechanical properties of freeze-dried HA-collagen scaffolds, the most common type of porous HA-collagen material, were first shown to be increased by the addition of HA reinforcements, but scaffold stiffness still fell far short of the desired range. Based on limitations inherent in the freeze-dried process, a new type of leached-porogen scaffold fabrication process was developed. Proof-of-concept scaffolds demonstrated the feasibility of producing leached-porogen HA-collagen materials, and the scaffold architecture was optimized though careful selection of porogen particle size and shape along with an improved crosslinking technique. The final scaffolds exhibited substantially increased compressive modulus compared to previous types HA-collagen scaffolds, while the porosity, pore size, and scaffold permeability were tailored to be suitable for bone tissue ingrowth. An in vitro study demonstrated the capacity of the leached-porogen scaffolds to serve as a substrate for the differentiation of osteoblasts and subsequent production of new bone tissue. The new leached-porogen scaffold HA-collagen scaffolds were

  20. Electrophoretic deposition of porous hydroxyapatite scaffold.

    PubMed

    Ma, J; Wang, C; Peng, K W

    2003-09-01

    Bioactive porous hydroxyapatite (HA) scaffold was fabricated using electrophoretic deposition (EPD) technique in the present work. Bulk HA scaffold was achieved by repeated deposition. The green scaffold was sintered at 1200 degrees C to 82% of the theoretical density. Scanning electron microscopy examination and mercury porosimetry measurement have shown that the porosity remains interconnected and a range of pore size from several microns to hundreds of microns was obtained. X-ray diffraction analysis was performed and confirmed that there is no HA decomposition during the sintering process. Mechanical characterization has also shown that the EPD scaffold possesses excellent properties. Cell culturing experiment was carried out and the result shows that the scaffold bioactivity is not only dependent on the interconnectivity of the pores, but also the pore size.

  1. Fabrication, characterization and cell cultures on a novel composite chitosan-nano-hydroxyapatite scaffold.

    PubMed

    Palazzo, B; Gallo, A; Casillo, A; Nitti, P; Ambrosio, L; Piconi, C

    2011-01-01

    This paper deals with the characterizations made during the development of a nano-HAp loaded chitosan scaffold, obtained by the freeze-drying technique combined with a novel in situ crystal growth method. The nano-composites were characterized by a highly porous and interconnected structure. The XRD patterns and calculated domain sizes of the HAp nano-crystals nucleated on the chitosan scaffolds are very similar to the ones recorded for deproteinated bone apatite. Both osteoblasts (MG63) and mesenchimal cells (hMSC) were showing good proliferation and adhesion onto the scaffolds. The presence of extensive filopodia and excellent spreading in and around the interconnected porous structure, indicated a strong cellular adhesion and growth. Moreover a good hMSC osteogenic differentiation has been verified. The observations related to well-developed structure morphology, physicochemical properties and high cytocompatibility suggest that the obtained chitosan-nHA porous scaffolds are potential candidate materials for bone regeneration.

  2. Fabrication and in vitro evaluation of an articular cartilage extracellular matrix-hydroxyapatite bilayered scaffold with low permeability for interface tissue engineering

    PubMed Central

    2014-01-01

    Background Osteochondral interface regeneration is challenging for functional and integrated cartilage repair. Various layered scaffolds have been used to reconstruct the complex interface, yet the influence of the permeability of the layered structure on cartilage defect healing remains largely unknown. Methods We designed and fabricated a novel bilayered scaffold using articular cartilage extracellular matrix (ACECM) and hydroxyapatite (HAp), involving a porous, oriented upper layer and a dense, mineralised lower layer. By optimising the HAp/ACECM ratio, differing pore sizes and porosities were obtained simultaneously in the two layers. To evaluate the effects of permeability on cell behaviour, rabbit chondrocytes were seeded. Results Morphological observations demonstrated that a gradual interfacial region was formed with pore sizes varying from 128.2 ± 20.3 to 21.2 ± 3.1 μm. The permeability of the bilayered scaffold decreased with increasing compressive strain and HAp content. Mechanical tests indicated that the interface was stable to bearing compressive and shear loads. Accordingly, the optimum HAp/ACECM ratio (7 w/v%) in the layer to mimic native calcified cartilage was found. Chondrocytes could not penetrate the interface and resided only in the upper layer, where they showed high cellularity and abundant matrix deposition. Conclusions Our findings suggest that a bilayered scaffold with low permeability, rather than complete isolation, represents a promising candidate for osteochondral interface tissue engineering. PMID:24950704

  3. Biocompatibility of hydroxyapatite scaffolds processed by lithography-based additive manufacturing.

    PubMed

    Tesavibul, Passakorn; Chantaweroad, Surapol; Laohaprapanon, Apinya; Channasanon, Somruethai; Uppanan, Paweena; Tanodekaew, Siriporn; Chalermkarnnon, Prasert; Sitthiseripratip, Kriskrai

    2015-01-01

    The fabrication of hydroxyapatite scaffolds for bone tissue engineering applications by using lithography-based additive manufacturing techniques has been introduced due to the abilities to control porous structures with suitable resolutions. In this research, the use of hydroxyapatite cellular structures, which are processed by lithography-based additive manufacturing machine, as a bone tissue engineering scaffold was investigated. The utilization of digital light processing system for additive manufacturing machine in laboratory scale was performed in order to fabricate the hydroxyapatite scaffold, of which biocompatibilities were eventually evaluated by direct contact and cell-culturing tests. In addition, the density and compressive strength of the scaffolds were also characterized. The results show that the hydroxyapatite scaffold at 77% of porosity with 91% of theoretical density and 0.36 MPa of the compressive strength are able to be processed. In comparison with a conventionally sintered hydroxyapatite, the scaffold did not present any cytotoxic signs while the viability of cells at 95.1% was reported. After 14 days of cell-culturing tests, the scaffold was able to be attached by pre-osteoblasts (MC3T3-E1) leading to cell proliferation and differentiation. The hydroxyapatite scaffold for bone tissue engineering was able to be processed by the lithography-based additive manufacturing machine while the biocompatibilities were also confirmed. PMID:26484553

  4. Biocompatibility of hydroxyapatite scaffolds processed by lithography-based additive manufacturing.

    PubMed

    Tesavibul, Passakorn; Chantaweroad, Surapol; Laohaprapanon, Apinya; Channasanon, Somruethai; Uppanan, Paweena; Tanodekaew, Siriporn; Chalermkarnnon, Prasert; Sitthiseripratip, Kriskrai

    2015-01-01

    The fabrication of hydroxyapatite scaffolds for bone tissue engineering applications by using lithography-based additive manufacturing techniques has been introduced due to the abilities to control porous structures with suitable resolutions. In this research, the use of hydroxyapatite cellular structures, which are processed by lithography-based additive manufacturing machine, as a bone tissue engineering scaffold was investigated. The utilization of digital light processing system for additive manufacturing machine in laboratory scale was performed in order to fabricate the hydroxyapatite scaffold, of which biocompatibilities were eventually evaluated by direct contact and cell-culturing tests. In addition, the density and compressive strength of the scaffolds were also characterized. The results show that the hydroxyapatite scaffold at 77% of porosity with 91% of theoretical density and 0.36 MPa of the compressive strength are able to be processed. In comparison with a conventionally sintered hydroxyapatite, the scaffold did not present any cytotoxic signs while the viability of cells at 95.1% was reported. After 14 days of cell-culturing tests, the scaffold was able to be attached by pre-osteoblasts (MC3T3-E1) leading to cell proliferation and differentiation. The hydroxyapatite scaffold for bone tissue engineering was able to be processed by the lithography-based additive manufacturing machine while the biocompatibilities were also confirmed.

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

    PubMed

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

    2015-04-01

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

  6. Open-Porous Hydroxyapatite Scaffolds for Three-Dimensional Culture of Human Adult Liver Cells

    PubMed Central

    Schmelzer, Eva; Over, Patrick; Nettleship, Ian; Gerlach, Joerg C.

    2016-01-01

    Liver cell culture within three-dimensional structures provides an improved culture system for various applications in basic research, pharmacological screening, and implantable or extracorporeal liver support. Biodegradable calcium-based scaffolds in such systems could enhance liver cell functionality by providing endothelial and hepatic cell support through locally elevated calcium levels, increased surface area for cell attachment, and allowing three-dimensional tissue restructuring. Open-porous hydroxyapatite scaffolds were fabricated and seeded with primary adult human liver cells, which were embedded within or without gels of extracellular matrix protein collagen-1 or hyaluronan. Metabolic functions were assessed after 5, 15, and 28 days. Longer-term cultures exhibited highest cell numbers and liver specific gene expression when cultured on hydroxyapatite scaffolds in collagen-1. Endothelial gene expression was induced in cells cultured on scaffolds without extracellular matrix proteins. Hydroxyapatite induced gene expression for cytokeratin-19 when cells were cultured in collagen-1 gel while culture in hyaluronan increased cytokeratin-19 gene expression independent of the use of scaffold in long-term culture. The implementation of hydroxyapatite composites with extracellular matrices affected liver cell cultures and cell differentiation depending on the type of matrix protein and the presence of a scaffold. The hydroxyapatite scaffolds enable scale-up of hepatic three-dimensional culture models for regenerative medicine applications. PMID:27403430

  7. Open-Porous Hydroxyapatite Scaffolds for Three-Dimensional Culture of Human Adult Liver Cells.

    PubMed

    Finoli, Anthony; Schmelzer, Eva; Over, Patrick; Nettleship, Ian; Gerlach, Joerg C

    2016-01-01

    Liver cell culture within three-dimensional structures provides an improved culture system for various applications in basic research, pharmacological screening, and implantable or extracorporeal liver support. Biodegradable calcium-based scaffolds in such systems could enhance liver cell functionality by providing endothelial and hepatic cell support through locally elevated calcium levels, increased surface area for cell attachment, and allowing three-dimensional tissue restructuring. Open-porous hydroxyapatite scaffolds were fabricated and seeded with primary adult human liver cells, which were embedded within or without gels of extracellular matrix protein collagen-1 or hyaluronan. Metabolic functions were assessed after 5, 15, and 28 days. Longer-term cultures exhibited highest cell numbers and liver specific gene expression when cultured on hydroxyapatite scaffolds in collagen-1. Endothelial gene expression was induced in cells cultured on scaffolds without extracellular matrix proteins. Hydroxyapatite induced gene expression for cytokeratin-19 when cells were cultured in collagen-1 gel while culture in hyaluronan increased cytokeratin-19 gene expression independent of the use of scaffold in long-term culture. The implementation of hydroxyapatite composites with extracellular matrices affected liver cell cultures and cell differentiation depending on the type of matrix protein and the presence of a scaffold. The hydroxyapatite scaffolds enable scale-up of hepatic three-dimensional culture models for regenerative medicine applications.

  8. Scaffold development using selective laser sintering of polyetheretherketone-hydroxyapatite biocomposite blends.

    PubMed

    Tan, K H; Chua, C K; Leong, K F; Cheah, C M; Cheang, P; Abu Bakar, M S; Cha, S W

    2003-08-01

    In tissue engineering (TE), temporary three-dimensional scaffolds are essential to guide cell proliferation and to maintain native phenotypes in regenerating biologic tissues or organs. To create the scaffolds, rapid prototyping (RP) techniques are emerging as fabrication techniques of choice as they are capable of overcoming many of the limitations encountered with conventional manual-based fabrication processes. In this research, RP fabrication of solvent free porous polymeric and composite scaffolds was investigated. Biomaterials such as polyetheretherketone (PEEK) and hydroxyapatite (HA) were experimentally processed on a commercial selective laser sintering (SLS) RP system. The SLS technique is highly advantageous as it provides good user control over the microstructures of created scaffolds by adjusting the SLS process parameters. Different weight percentage (wt%) compositions of physically mixed PEEK/HA powder blends were sintered to assess their suitability for SLS processing. Microstructural assessments of the scaffolds were conducted using electron microscopy. The results ascertained the potential of SLS-fabricated TE scaffolds. PMID:12895584

  9. Calcium silicate ceramic scaffolds toughened with hydroxyapatite whiskers for bone tissue engineering

    SciTech Connect

    Feng, Pei; Wei, Pingpin; Li, Pengjian; Gao, Chengde; Shuai, Cijun; Peng, Shuping

    2014-11-15

    Calcium silicate possessed excellent biocompatibility, bioactivity and degradability, while the high brittleness limited its application in load-bearing sites. Hydroxyapatite whiskers ranging from 0 to 30 wt.% were incorporated into the calcium silicate matrix to improve the strength and fracture resistance. Porous scaffolds were fabricated by selective laser sintering. The effects of hydroxyapatite whiskers on the mechanical properties and toughening mechanisms were investigated. The results showed that the scaffolds had a uniform and continuous inner network with the pore size ranging between 0.5 mm and 0.8 mm. The mechanical properties were enhanced with increasing hydroxyapatite whiskers, reached a maximum at 20 wt.% (compressive strength: 27.28 MPa, compressive Young's modulus: 156.2 MPa, flexural strength: 15.64 MPa and fracture toughness: 1.43 MPa·m{sup 1/2}) and then decreased by addition of more hydroxyapatite whiskers. The improvement of mechanical properties was due to whisker pull-out, crack deflection and crack bridging. Moreover, the degradation rate decreased with the increase of hydroxyapatite whisker content. A layer of bone-like apatite was formed on the scaffold surfaces after being soaked in simulated body fluid. Human osteoblast-like MG-63 cells spread well on the scaffolds and proliferated with increasing culture time. These findings suggested that the calcium silicate scaffolds reinforced with hydroxyapatite whiskers showed great potential for bone regeneration and tissue engineering applications. - Highlights: • HA whiskers were incorporated into CS to improve the properties. • The scaffolds were successfully fabricated by SLS. • Toughening mechanisms was whisker pull-out, crack deflection and bridging. • The scaffolds showed excellent apatite forming ability.

  10. Recent Advances in Hydroxyapatite Scaffolds Containing Mesenchymal Stem Cells

    PubMed Central

    Michel, John; Penna, Matthew; Kochen, Juan; Cheung, Herman

    2015-01-01

    Modern day tissue engineering and cellular therapies have gravitated toward using stem cells with scaffolds as a dynamic modality to aid in differentiation and tissue regeneration. Mesenchymal stem cells (MSCs) are one of the most studied stem cells used in combination with scaffolds. These cells differentiate along the osteogenic lineage when seeded on hydroxyapatite containing scaffolds and can be used as a therapeutic option to regenerate various tissues. In recent years, the combination of hydroxyapatite and natural or synthetic polymers has been studied extensively. Due to the interest in these scaffolds, this review will cover the wide range of hydroxyapatite containing scaffolds used with MSCs for in vitro and in vivo experiments. Further, in order to maintain a progressive scope of the field this review article will only focus on literature utilizing adult human derived MSCs (hMSCs) published in the last three years. PMID:26106425

  11. [IN VIVO EVALUATION OF POLYCAPROLACTONE-HYDROXYAPATITE SCAFFOLD BIOCOMPATIBILITY].

    PubMed

    Ivanov, A N; Kozadaev, M N; Bogomolova, N V; Matveeva, O V; Puchinyan, D M; Norkin, I A; Sal'kovskii, Yu E; Lyubun, G P

    2015-01-01

    Biocompatibility is one of the main and very important properties for scaffolds. The aim of the present study was to investigate cells population dynamics in vivo in the process of original polycaprolactone-hydroxyapatite scaffold colonization, as well as tissue reactions to the implantation to assess the biocompatibility of the matrix. It has been found that tissue reactive changes in white rats subside completely up to the 21st day after subcutaneous polycaprolactone-hydroxyapatite scaffold implantation. Matrix was actively colonized by connective tissue cells in the period from the 7th to the 21st day of the experiment. However, intensive scaffold vascularization started from the 14th day after implantation. These findings suggest a high degree of the polycaprolactone-hydroxyapatite scaffold biocompatiblilitye.

  12. Recent Advances in Hydroxyapatite Scaffolds Containing Mesenchymal Stem Cells.

    PubMed

    Michel, John; Penna, Matthew; Kochen, Juan; Cheung, Herman

    2015-01-01

    Modern day tissue engineering and cellular therapies have gravitated toward using stem cells with scaffolds as a dynamic modality to aid in differentiation and tissue regeneration. Mesenchymal stem cells (MSCs) are one of the most studied stem cells used in combination with scaffolds. These cells differentiate along the osteogenic lineage when seeded on hydroxyapatite containing scaffolds and can be used as a therapeutic option to regenerate various tissues. In recent years, the combination of hydroxyapatite and natural or synthetic polymers has been studied extensively. Due to the interest in these scaffolds, this review will cover the wide range of hydroxyapatite containing scaffolds used with MSCs for in vitro and in vivo experiments. Further, in order to maintain a progressive scope of the field this review article will only focus on literature utilizing adult human derived MSCs (hMSCs) published in the last three years.

  13. Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold.

    PubMed

    Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

    2014-02-01

    The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials.

  14. Effects of degradation and porosity on the load bearing properties of model hydroxyapatite bone scaffolds.

    SciTech Connect

    Dellinger, Jennifer Gwynne; Cesarano, Joseph, III; Jamison, Russell D.; Wojtowicz, Abigail M.

    2005-06-01

    Degradation of three types of model hydroxyapatite (HA) scaffolds was studied after in vitro degradation in a sodium acetate buffer (pH 4). Degradation was evaluated using compression testing, scanning electron microscopy (SEM), inductively coupled plasma (ICP) analysis, and weight measurements. Scaffolds were fabricated with a solid freeform fabrication (SFF) technique based on the robotic deposition of colloidal pastes. Scaffolds had a macrostructure resembling a lattice of rods. Scaffolds contained either macropores (270 or 680 m in the x-y direction and 280 m in the z-direction) and micropores (1-30-m pores and pores <1 m) or only macropores pores (270 m in the x-y direction and 280 m in the z-direction). A computer-aided design (CAD) program controlled the size and distribution of macropores; micropores were created by polymethylmethacrylate (PMMA) microsphere porogens (1-30-m pore diameter) and controlled sintering (pores <1 m). Percent weight loss of the scaffolds and calcium and phosphorus ion concentrations in solution increased as the degradation period increased for all scaffold types. After degradation, compressive strength and compressive modulus decreased significantly for those scaffolds with microporosity. For scaffolds without microporosity, the changes in strength and modulus after degradation were not statistically significant. The compressive strength of scaffolds without microporosity was significantly greater than the scaffolds with microporosity.

  15. Precipitation of hydroxyapatite on electrospun polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds for bone tissue engineering.

    PubMed

    Shanmugavel, Suganya; Reddy, Venugopal Jayarama; Ramakrishna, Seeram; Lakshmi, B S; Dev, Vr Giri

    2014-07-01

    Advances in electrospun nanofibres with bioactive materials have enhanced the scope of fabricating biomimetic scaffolds for tissue engineering. The present research focuses on fabrication of polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds by electrospinning followed by hydroxyapatite deposition by calcium-phosphate dipping method for bone tissue engineering. Morphology, composition, hydrophilicity and mechanical properties of polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds along with controls polycaprolactone and polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds were examined by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle and tensile tests, respectively. Adipose-derived stem cells cultured on polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds displayed highest cell proliferation, increased osteogenic markers expression (alkaline phosphatase and osteocalcin), osteogenic differentiation and increased mineralization in comparison with polycaprolactone control. The obtained results indicate that polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds have appropriate physico-chemical and biological properties to be used as biomimetic scaffolds for bone tissue regeneration.

  16. Fabrication of polycaprolactone nanofibrous scaffolds by facile phase separation approach.

    PubMed

    Liu, Shuqiong; He, Zhihang; Xu, Guojie; Xiao, Xiufeng

    2014-11-01

    Three-dimensional polycaprolactone (PCL) scaffolds with spherulite and nanofibrous structures were fabricated for the first time by thermally induced phase separation from a ternary PCL/dioxane/water system. Moreover, the effects of polymer concentration, aging temperature and the ratio of dioxane to water on the morphology of nanofibrous scaffolds were investigated. The result revealed that gelation, aging temperature, and ratio of solvents significantly influenced the formation of the unique spherulite and nanofibrous structures. The apatite-formation ability test showed relatively rapid growth of carbonate hydroxyapatite in the nanofibrous PCL scaffold with macropore compared to the other two scaffolds with smooth structure and nanofibrous structure without macropore, respectively, indicating good apatite-formation ability of the macroporous and nanofibrous PCL scaffolds.

  17. Robocasting nanocomposite scaffolds of poly(caprolactone)/hydroxyapatite incorporating modified carbon nanotubes for hard tissue reconstruction.

    PubMed

    Dorj, Biligzaya; Won, Jong-Eun; Kim, Joong-Hyun; Choi, Seong-Jun; Shin, Ueon Sang; Kim, Hae-Won

    2013-06-01

    Nanocomposite scaffolds with tailored 3D pore configuration are promising candidates for the reconstruction of bone. Here we fabricated novel nanocomposite bone scaffolds through robocasting. Poly(caprolactone) (PCL)-hydroxyapatite (HA) slurry containing ionically modified carbon nanotubes (imCNTs) was robotic-dispensed and structured layer-by-layer into macrochanneled 3D scaffolds under adjusted processing conditions. Homogeneous dispersion of imCNTs (0.2 wt % relative to PCL-HA) was achieved in acetone, aiding in the preparation of PCL-HA-imCNTs slurry with good mixing property. Incorporation of imCNTs into PCL-HA composition significantly improved the compressive strength and elastic modulus of the robotic-dispensed scaffolds (~1.5-fold in strength and ~2.5-fold in elastic modulus). When incubated in simulated body fluid (SBF), PCL-HA-imCNT nanocomposite scaffold induced substantial mineralization of apatite in a similar manner to the PCL-HA scaffold, which was contrasted in pure PCL scaffold. MC3T3-E1 cell culture on the scaffolds demonstrated that cell proliferation levels were significantly higher in both PCL-HA-imCNT and PCL-HA than in pure PCL, and no significant difference was found between the nanocomposite scaffolds. When the PCL-HA-imCNT scaffold was implanted into a rat subcutaneous tissue for 4 weeks, soft fibrous tissues with neo-blood vessels formed well in the pore channels of the scaffolds without any significant inflammatory signs. Tissue reactions in PCL-HA-imCNT scaffold were similar to those in PCL-HA scaffold, suggesting incorporated imCNT did not negate the beneficial biological roles of HA. While more long-term in vivo research in bone defect models is needed to confirm clinical availability, our results suggest robotic-dispensed PCL-HA-imCNT nanocomposite scaffolds can be considered promising new candidate matrices for bone regeneration.

  18. Osteoinductive silk fibroin/titanium dioxide/hydroxyapatite hybrid scaffold for bone tissue engineering.

    PubMed

    Kim, Jung-Ho; Kim, Dong-Kyu; Lee, Ok Joo; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Lee, Jun Ho; Park, Chan Hum

    2016-01-01

    The present study demonstrated the fabrication that incorporation of titanium isopropoxide (TiO2) and hydroxyapatite (HA) nanoparticles into the silk fibroin (SF) scaffolds. In this process, we prepared TiO2 nanoparticles using sol-gel synthesis and the porous structure was developed by salt-leaching process. Homogeneous distribution of TiO2 and HA nanoparticles were confirmed by images of VP-FE-SEM and those equipped with energy dispersive X-ray spectrometer. Structural characteristics of the porous SF/TiO2/HA hybrid scaffold were also determined using FTIR analysis and X-ray diffractometer. In this study, the porous SF/TiO2/HA hybrid scaffold showed similar porosity, enhanced mechanical property, but decreased water binding abilities, compared with the porous SF scaffold. For evaluation of the osteogenic differentiation of rat bone marrow mesenchymal stem cells, alkaline phosphatase activity and osteogenic gene expression were employed. Our results revealed that the porous SF/TiO2/HA hybrid scaffold had improved osteoinductivity compared with the porous SF scaffold. These results suggest that the osteogenic property as well as mechanical property of the porous SF/TiO2/HA hybrid scaffold could be better than the porous SF scaffold. Therefore, the porous SF/TiO2/HA hybrid scaffold may be a good promising biomaterial for bone tissue engineering application.

  19. Hydroxyapatite Whisker Reinforced 63s Glass Scaffolds for Bone Tissue Engineering

    PubMed Central

    Shuai, Cijun; Cao, Yiyuan; Gao, Chengde; Feng, Pei; Xiao, Tao; Peng, Shuping

    2015-01-01

    Bioactive glass (BG) is widely used for bone tissue engineering. However, poor mechanical properties are the major shortcomings. In the study, hydroxyapatite nanowhisker (HANw) was used as a reinforcement to improve the mechanical properties. 63s glass/HANw scaffolds were successfully fabricated by selective laser sintering (SLS). It was found that the optimal compressive strength and fracture toughness were achieved when 10 wt.% HANw was added. This led to 36% increase in compressive strength and 83% increase in fracture toughness, respectively, compared with pure 63s glass scaffolds. Different reinforcement mechanisms were analyzed based on the microstructure investigation. Whisker bridging and whisker pulling-out were efficient in absorbing crack propagating energy, resulting in the improvement of the mechanical properties. Moreover, bioactivity and biocompatibility of the scaffolds were evaluated in vitro. The results showed that composite scaffolds with 10 wt.% HANw exhibited good apatite-forming ability and cellular affinity. PMID:25821798

  20. Injectable porous nano-hydroxyapatite/chitosan/tripolyphosphate scaffolds with improved compressive strength for bone regeneration.

    PubMed

    Uswatta, Suren P; Okeke, Israel U; Jayasuriya, Ambalangodage C

    2016-12-01

    In this study we have fabricated porous injectable spherical scaffolds using chitosan biopolymer, sodium tripolyphosphate (TPP) and nano-hydroxyapatite (nHA). TPP was primarily used as an ionic crosslinker to crosslink nHA/chitosan droplets. We hypothesized that incorporating nHA into chitosan could support osteoconduction by emulating the mineralized cortical bone structure, and improve the Ultimate Compressive Strength (UCS) of the scaffolds. We prepared chitosan solutions with 0.5%, 1% and 2% (w/v) nHA concentration and used simple coacervation and lyophilization techniques to obtain spherical scaffolds. Lyophilized spherical scaffolds had a mean diameter of 1.33mm (n=25). Further, portion from each group lyophilized scaffolds were soaked and dried to obtain Lyophilized Soaked and Dried (LSD) scaffolds. LSD scaffolds had a mean diameter of 0.93mm (n=25) which is promising property for the injectability. Scanning Electron Microscopy images showed porous surface morphology and interconnected pore structures inside the scaffolds. Lyophilized and LSD scaffolds had surface pores <10 and 2μm, respectively. 2% nHA/chitosan LSD scaffolds exhibited UCS of 8.59MPa compared to UCS of 2% nHA/chitosan lyophilized scaffolds at 3.93MPa. Standardize UCS values were 79.98MPa and 357MPa for 2% nHA/chitosan lyophilized and LSD particles respectively. One-way ANOVA results showed a significant increase (p<0.001) in UCS of 1% and 2% nHA/chitosan lyophilized scaffolds compared to 0% and 0.5% nHA/chitosan lyophilized scaffolds. Moreover, 2% nHA LSD scaffolds had significantly increased (p<0.005) their mean UCS by 120% compared to 2% nHA lyophilized scaffolds. In a drawback, all scaffolds have lost their mechanical properties by 95% on the 2nd day when fully immersed in phosphate buffered saline. Additionally live and dead cell assay showed no cytotoxicity and excellent osteoblast attachment to both lyophilized and LSD scaffolds at the end of 14th day of in vitro studies. 2% n

  1. Electrospun polyurethane/hydroxyapatite bioactive scaffolds for bone tissue engineering: the role of solvent and hydroxyapatite particles.

    PubMed

    Tetteh, G; Khan, A S; Delaine-Smith, R M; Reilly, G C; Rehman, I U

    2014-11-01

    Polyurethane (PU) is a promising polymer to support bone-matrix producing cells due to its durability and mechanical resistance. In this study two types of medical grade poly-ether urethanes Z3A1 and Z9A1 and PU-Hydroxyapatite (PU-HA) composites were investigated for their ability to act as a scaffold for tissue engineered bone. PU dissolved in varying concentrations of dimethylformamide (DMF) and tetrahydrofuran (THF) solvents were electrospun to attain scaffolds with randomly orientated non-woven fibres. Bioactive polymeric composite scaffolds were created using 15 wt% Z3A1 in a 70/30 DMF/THF PU solution and incorporating micro- or nano-sized HA particles in a ratio of 3:1 respectively, whilst a 25 wt% Z9A1 PU solution was doped in ratio of 5:1. Chemical properties of the resulting composites were evaluated by FTIR and physical properties by SEM. Tensile mechanical testing was carried out on all electrospun scaffolds. MLO-A5 osteoblastic mouse cells and human embryonic mesenchymal progenitor cells, hES-MPs were seeded on the scaffolds to test their biocompatibility and ability to support mineralised matrix production over a 28 day culture period. Cell viability was assayed by MTT and calcium and collagen deposition by Sirius red and alizarin red respectively. SEM images of both electrospun PU scaffolds and PU-HA composite scaffolds showed differences in fibre morphology with changes in solvent combinations and size of HA particles. Inclusion of THF eliminated the presence of beads in fibres that were present in scaffolds fabricated with 100% DMF solvent, and resulted in fibres with a more uniform morphology and thicker diameters. Mechanical testing demonstrated that the Young׳s Modulus and yield strength was lower at higher THF concentrations. Inclusion of both sizes of HA particles in PU-HA solutions reinforced the scaffolds leading to higher mechanical properties, whilst FTIR characterisation confirmed the presence of HA in all composite scaffolds. Although

  2. Periodontal regeneration with stem cells-seeded collagen-hydroxyapatite scaffold.

    PubMed

    Liu, Zeping; Yin, Xing; Ye, Qingsong; He, Wulin; Ge, Mengke; Zhou, Xiaofu; Hu, Jing; Zou, Shujuan

    2016-07-01

    Re-establishing compromised periodontium to its original structure, properties and function is demanding, but also challenging, for successful orthodontic treatment. In this study, the periodontal regeneration capability of collagen-hydroxyapatite scaffolds, seeded with bone marrow stem cells, was investigated in a canine labial alveolar bone defect model. Bone marrow stem cells were isolated, expanded and characterized. Porous collagen-hydroxyapatite scaffold and cross-linked collagen-hydroxyapatite scaffold were prepared. Attachment, migration, proliferation and morphology of bone marrow stem cells, co-cultured with porous collagen-hydroxyapatite or cross-linked collagen-hydroxyapatite, were evaluated in vitro. The periodontal regeneration capability of collagen-hydroxyapatite scaffold with or without bone marrow stem cells was tested in six beagle dogs, with each dog carrying one sham-operated site as healthy control, and three labial alveolar bone defects untreated to allow natural healing, treated with bone marrow stem cells - collagen-hydroxyapatite scaffold implant or collagen-hydroxyapatite scaffold implant, respectively. Animals were euthanized at 3 and 6 months (3 animals per group) after implantation and the resected maxillary and mandibular segments were examined using micro-computed tomography scan, H&E staining, Masson's staining and histometric evaluation. Bone marrow stem cells were successfully isolated and demonstrated self-renewal and multi-potency in vitro. The porous collagen-hydroxyapatite and cross-linked collagen-hydroxyapatite had average pore sizes of 415 ± 20 µm and 203 ± 18 µm and porosity of 69 ± 0.5% and 50 ± 0.2%, respectively. The attachment, proliferation and migration of bone marrow stem cells were satisfactory on both porous collagen-hydroxyapatite and cross-linked collagen-hydroxyapatite scaffolds. Implantation of bone marrow stem cells - collagen-hydroxyapatite or collagen-hydroxyapatite scaffold in

  3. Hydroxyapatite/polylactide biphasic combination scaffold loaded with dexamethasone for bone regeneration.

    PubMed

    Son, Jun-Sik; Kim, Su-Gwan; Oh, Ji-Su; Appleford, Mark; Oh, Sunho; Ong, Joo L; Lee, Kyu-Bok

    2011-12-15

    This study presents a novel design of a ceramic/polymer biphasic combination scaffold that mimics natural bone structures and is used as a bone graft substitute. To mimic the natural bone structures, the outside cortical-like shells were composed of porous hydroxyapatite (HA) with a hollow interior using a polymeric template-coating technique; the inner trabecular-like core consisted of porous poly(D,L-lactic acid) (PLA) that was loaded with dexamethasone (DEX) and was directly produced using a particle leaching/gas forming technique to create the inner diameter of the HA scaffold. It was observed that the HA and PLA parts of the fabricated HA/PLA biphasic scaffold contained open and interconnected pore structures, and the boundary between both parts was tightly connected without any gaps. It was found that the structure of the combination scaffold was analogous to that of natural bone based on micro-computed tomography analysis. Additionally, the dense, uniform apatite layer was formed on the surface of the HA/PLA biphasic scaffold through a biomimetic process, and DEX was successfully released from the PLA of the biphasic scaffold over a 1-month period. This release caused human embryonic palatal mesenchyme cells to proliferate, differentiate, produce ECM, and form tissue in vitro. Therefore, it was concluded that this functionally graded scaffold is similar to natural bone and represents a potential bone-substitute material.

  4. Osseointegrative Properties of Electrospun Hydroxyapatite-Containing Nanofibrous Chitosan Scaffolds

    PubMed Central

    Frohbergh, Michael E.; Katsman, Anya; Mondrinos, Mark J.; Stabler, Collin T.; Hankenson, Kurt D.; Oristaglio, Jeffrey T.

    2015-01-01

    Our long-term goal is to develop smart biomaterials that can facilitate regeneration of critical-size craniofacial lesions. In this study, we tested the hypothesis that biomimetic scaffolds electrospun from chitosan (CTS) will promote tissue repair and regeneration in a critical size calvarial defect. To test this hypothesis, we first compared in vitro ability of electrospun CTS scaffolds crosslinked with genipin (CTS-GP) to those of mineralized CTS-GP scaffolds containing hydroxyapatite (CTS-HA-GP), by assessing proliferation/metabolic activity and alkaline phosphatase (ALP) levels of murine mesenchymal stem cells (mMSCs). The cells' metabolic activity exhibited a biphasic behavior, indicative of initial proliferation followed by subsequent differentiation for all scaffolds. ALP activity of mMSCs, a surrogate measure of osteogenic differentiation, increased over time in culture. After 3 weeks in maintenance medium, ALP activity of mMSCs seeded onto CTS-HA-GP scaffolds was approximately two times higher than that of cells cultured on CTS-GP scaffolds. The mineralized CTS-HA-GP scaffolds were also osseointegrative in vivo, as inferred from the enhanced bone regeneration in a murine model of critical size calvarial defects. Tissue regeneration was evaluated over a 3 month period by microCT and histology (Hematoxylin and Eosin and Masson's Trichrome). Treatment of the lesions with CTS-HA-GP scaffolds induced a 38% increase in the area of de novo generated mineralized tissue area after 3 months, whereas CTS-GP scaffolds only led to a 10% increase. Preseeding with mMSCs significantly enhanced the regenerative capacity of CTS-GP scaffolds (by ∼3-fold), to 35% increase in mineralized tissue area after 3 months. CTS-HA-GP scaffolds preseeded with mMSCs yielded 45% new mineralized tissue formation in the defects. We conclude that the presence of HA in the CTS-GP scaffolds significantly enhances their osseointegrative capacity and that mineralized chitosan-based scaffolds

  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. Effect of different hydroxyapatite incorporation methods on the structural and biological properties of porous collagen scaffolds for bone repair.

    PubMed

    Ryan, Alan J; Gleeson, John P; Matsiko, Amos; Thompson, Emmet M; O'Brien, Fergal J

    2015-12-01

    Scaffolds which aim to provide an optimised environment to regenerate bone tissue require a balance between mechanical properties and architecture known to be conducive to enable tissue regeneration, such as a high porosity and a suitable pore size. Using freeze-dried collagen-based scaffolds as an analogue of native ECM, we sought to improve the mechanical properties by incorporating hydroxyapatite (HA) in different ways while maintaining a pore architecture sufficient to allow cell infiltration, vascularisation and effective bone regeneration. Specifically we sought to elucidate the effect of different hydroxyapatite incorporation methods on the mechanical, morphological, and cellular response of the resultant collagen-HA scaffolds. The results demonstrated that incorporating either micron-sized (CHA scaffolds) or nano-sized HA particles (CnHA scaffolds) prior to freeze-drying resulted in moderate increases in stiffness (2.2-fold and 6.2-fold, respectively, vs. collagen-glycosaminoglycan scaffolds, P < 0.05, a scaffold known to support osteogenesis), while enabling good cell attachment, and moderate mesenchymal stem cell (MSC)-mediated calcium production after 28 days' culture (2.1-fold, P < 0.05, and 1.3-fold, respectively, vs. CG scaffolds). However, coating of collagen scaffolds with a hydroxyapatite precipitate after freeze-drying (CpHA scaffolds) has been shown to be a highly effective method to increase the compressive modulus (26-fold vs. CG controls, P < 0.001) of scaffolds while maintaining a high porosity (~ 98%). The coating of the ligand-dense collagen structure results in a lower cell attachment level (P < 0.05), although it supported greater cell-mediated calcium production (P < 0.0001) compared with other scaffold variants after 28 days' culture. The comparatively good mechanical properties of these high porosity scaffolds is obtained partially through highly crosslinking the scaffolds with both a physical (DHT) and chemical (EDAC) crosslinking

  7. Microcracks induce osteoblast alignment and maturation on hydroxyapatite scaffolds

    NASA Astrophysics Data System (ADS)

    Shu, Yutian

    Physiological bone tissue is a mineral/collagen composite with a hierarchical structure. The features in bone, such as mineral crystals, fibers, and pores can range from the nanometer to the centimeter in size. Currently available bone tissue scaffolds primarily address the chemical composition, pore size, and pore size distribution. While these design parameters are extensively investigated for mimicking bone function and inducing bone regeneration, little is known about microcracks, which is a prevalent feature found in fractured bone in vivo and associated with fracture healing and repair. Since the purpose of bone tissue engineering scaffold is to enhance bone regeneration, the coincidence of microcracks and bone densification should not be neglected but rather be considered as a potential parameter in bone tissue engineering scaffold design. The purpose of this study is to test the hypothesis that microcracks enhance bone healing. In vitro studies were designed to investigate the osteoblast (bone forming cells) response to microcracks in dense (94%) hydroxyapatite substrates. Microcracks were introduced using a well-established Vickers indentation technique. The results of our study showed that microcracks induced osteoblast alignment, enhanced osteoblast attachment and more rapid maturation. These findings may provide insight into fracture healing mechanism(s) as well as improve the design of bone tissue engineering orthopedic scaffolds for more rapid bone regeneration.

  8. Selenium-Substituted Hydroxyapatite/Biodegradable Polymer/Pamidronate Combined Scaffold for the Therapy of Bone Tumour

    PubMed Central

    Oledzka, Ewa; Sobczak, Marcin; Kolmas, Joanna; Nalecz-Jawecki, Grzegorz

    2015-01-01

    The present study evaluated a new concept of combined scaffolds as a promising bone replacement material for patients with a bone tumour or bone metastasis. The scaffolds were composed of hydroxyapatite doped with selenium ions and a biodegradable polymer (linear or branched), and contained an active substance—bisphosphonate. For this purpose, a series of biodegradable polyesters were synthesized through a ring-opening polymerization of ε-caprolactone or d,l-lactide in the presence of 2-hydroxyethyl methacrylate (HEMA) or hyperbranched 2,2-bis(hydroxymethyl)propionic acid polyester-16-hydroxyl (bis-MPA) initiators, substances often used in the synthesis of medical materials. The polymers were obtained with a high yield and a number-average molecular weight up to 45,300 (g/mol). The combined scaffolds were then manufactured by a direct compression of pre-synthesized hydroxyapatite doped with selenite or selenate ions, obtained polymer and pamidronate as a model drug. It was found that the kinetic release of the drug from the scaffolds tested in vitro under physiological conditions is strongly dependent on the physicochemical properties and average molecular weight of the polymers. Furthermore, there was good correlation with the hydrolytic biodegradation results of the scaffolds fabricated without drug. The preliminary findings suggest that the fabricated combined scaffolds could be effectively used for the sustained delivery of bioactive molecules at bone defect sites. PMID:26389884

  9. Selenium-Substituted Hydroxyapatite/Biodegradable Polymer/Pamidronate Combined Scaffold for the Therapy of Bone Tumour.

    PubMed

    Oledzka, Ewa; Sobczak, Marcin; Kolmas, Joanna; Nalecz-Jawecki, Grzegorz

    2015-09-14

    The present study evaluated a new concept of combined scaffolds as a promising bone replacement material for patients with a bone tumour or bone metastasis. The scaffolds were composed of hydroxyapatite doped with selenium ions and a biodegradable polymer (linear or branched), and contained an active substance-bisphosphonate. For this purpose, a series of biodegradable polyesters were synthesized through a ring-opening polymerization of ε-caprolactone or d,l-lactide in the presence of 2-hydroxyethyl methacrylate (HEMA) or hyperbranched 2,2-bis(hydroxymethyl)propionic acid polyester-16-hydroxyl (bis-MPA) initiators, substances often used in the synthesis of medical materials. The polymers were obtained with a high yield and a number-average molecular weight up to 45,300 (g/mol). The combined scaffolds were then manufactured by a direct compression of pre-synthesized hydroxyapatite doped with selenite or selenate ions, obtained polymer and pamidronate as a model drug. It was found that the kinetic release of the drug from the scaffolds tested in vitro under physiological conditions is strongly dependent on the physicochemical properties and average molecular weight of the polymers. Furthermore, there was good correlation with the hydrolytic biodegradation results of the scaffolds fabricated without drug. The preliminary findings suggest that the fabricated combined scaffolds could be effectively used for the sustained delivery of bioactive molecules at bone defect sites.

  10. Poly(ε-caprolactone)/nano fluoridated hydroxyapatite scaffolds for bone tissue engineering: in vitro degradation and biocompatibility study.

    PubMed

    Johari, N; Fathi, M H; Golozar, M A; Erfani, E; Samadikuchaksaraei, A

    2012-03-01

    In this study, biodegradation and biocompatibility of novel poly(ε-caparolactone)/nano fluoridated hydroxyapatite (PCL-FHA) scaffolds were investigated. The FHA nanopowders were prepared via mechanical alloying method and had a chemical composition of Ca(10)(PO(4))(6)OH(2-x )F(x) (where x values were selected equal to 0.5 and 2.0). In order to fabricate PCL-FHA scaffolds, 10, 20, 30 and 40 wt% of the FHA were added to the PCL. The PCL-FHA scaffolds were produced by the solvent casting/particulate leaching using sodium chloride particles (with diameters of 300-500 μm) as the porogen. The phase structure, microstructure and morphology of the scaffolds were evaluated using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques. Porosity of the scaffolds was measured using the Archimedes' Principle. In vitro degradation of PCL-FHA scaffolds was studied by incubating the samples in phosphate buffered saline at 37°C and pH 7.4 for 30 days. Moreover, biocompatibility was evaluated by MTT assay after seeding and culture of osteoblast-like cells on the scaffolds. Results showed that the osteoblast-like cells attached to and proliferated on PCL-FHA and increasing the porosity of the scaffolds increased the cell viability. Also, degradation rate of scaffolds were increased with increasing the fluorine content in scaffolds composition. PMID:22190197

  11. The influence of electrospun fibre scaffold orientation and nano-hydroxyapatite content on the development of tooth bud stem cells in vitro.

    PubMed

    van Manen, Elisabeth H C; Zhang, Weibo; Walboomers, X Frank; Vazquez, Betsy; Yang, Fang; Ji, Wei; Yu, Na; Spear, Daisy J; Jansen, John A; Yelick, Pamela C

    2014-01-01

    In stem cell-based dental tissue engineering, the goal is to create tooth-like structures using scaffold materials to guide the dental stem cells. In this study, the effect of fiber alignment and hydroxyapatite content in biodegradable electrospun PLGA scaffolds have been investigated. Fiber orientation of the scaffolds was random or aligned in bundles. For scaffolds with prefabricated orientation, scaffolds were fabricated from PLGA polymer solution containing 0, 10 or 20 % nano-hydroxyapatite. The scaffolds were seeded with porcine cells isolated from tooth buds (dental mesenchymal, dental epithelial, and mixed dental mesenchymal/epithelial cells). Samples were collected at 1, 3 and 6 weeks. Analyses were performed for cell proliferation, ALP activity, and cell morphology. Fiber alignment showed an effect on cell orientation in the first week after cell seeding, but had no long-term effect on cell alignment or organized calcified matrix deposition once the cells reach confluency. Scaffold porosity was sufficient to allow migration of mesenchymal cells. Hydroxyapatite incorporation did not have a positive effect on cell proliferation, especially of epithelial cells, but seemed to promote differentiation. Concluding, scaffold architecture is important to mesenchymal cell morphology, but has no long-term effect on cell alignment or organized ECM deposition. nHA incorporation does have an effect on cell proliferation, differentiation and ECM production, and should be regarded as a bioactive component of dental bioengineered scaffolds.

  12. 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.

  13. 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

  14. 3D printing of porous hydroxyapatite scaffolds intended for use in bone tissue engineering applications.

    PubMed

    Cox, Sophie C; Thornby, John A; Gibbons, Gregory J; Williams, Mark A; Mallick, Kajal K

    2015-02-01

    A systematic characterisation of bone tissue scaffolds fabricated via 3D printing from hydroxyapatite (HA) and poly(vinyl)alcohol (PVOH) composite powders is presented. Flowability of HA:PVOH precursor materials was observed to affect mechanical stability, microstructure and porosity of 3D printed scaffolds. Anisotropic behaviour of constructs and part failure at the boundaries of interlayer bonds was highlighted by compressive strength testing. A trade-off between the ability to facilitate removal of PVOH thermal degradation products during sintering and the compressive strength of green parts was revealed. The ultimate compressive strength of 55% porous green scaffolds printed along the Y-axis and dried in a vacuum oven for 6h was 0.88 ± 0.02 MPa. Critically, the pores of 3D printed constructs could be user designed, ensuring bulk interconnectivity, and the imperfect packing of powder particles created an inherent surface roughness and non-designed porosity within the scaffold. These features are considered promising since they are known to facilitate osteoconduction and osteointegration in-vivo. Characterisation techniques utilised in this study include two funnel flow tests, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), compressive strength testing and computed tomography (CT).

  15. 3D printing of porous hydroxyapatite scaffolds intended for use in bone tissue engineering applications.

    PubMed

    Cox, Sophie C; Thornby, John A; Gibbons, Gregory J; Williams, Mark A; Mallick, Kajal K

    2015-02-01

    A systematic characterisation of bone tissue scaffolds fabricated via 3D printing from hydroxyapatite (HA) and poly(vinyl)alcohol (PVOH) composite powders is presented. Flowability of HA:PVOH precursor materials was observed to affect mechanical stability, microstructure and porosity of 3D printed scaffolds. Anisotropic behaviour of constructs and part failure at the boundaries of interlayer bonds was highlighted by compressive strength testing. A trade-off between the ability to facilitate removal of PVOH thermal degradation products during sintering and the compressive strength of green parts was revealed. The ultimate compressive strength of 55% porous green scaffolds printed along the Y-axis and dried in a vacuum oven for 6h was 0.88 ± 0.02 MPa. Critically, the pores of 3D printed constructs could be user designed, ensuring bulk interconnectivity, and the imperfect packing of powder particles created an inherent surface roughness and non-designed porosity within the scaffold. These features are considered promising since they are known to facilitate osteoconduction and osteointegration in-vivo. Characterisation techniques utilised in this study include two funnel flow tests, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), compressive strength testing and computed tomography (CT). PMID:25492194

  16. Direct writing of porous tissue scaffolds based on Vaseline-doped hydroxyapatite inks

    NASA Astrophysics Data System (ADS)

    Li, Ya-Yun; Li, Long-Tu; Li, Bo

    2015-05-01

    A novel type of 40 vol.% hydroxyapatite (HAp), Ca10(PO4)6(OH)2, suspension doped with Vaseline was developed, and porous three-dimensional (3D) scaffolds were fabricated by using a direct ink writing (DIW) method. The preparation of the HAp inks and the principles of the DIW technique were investigated. The microporosity of the scaffold wall increased after introducing the Vaseline, whereas macroporosity can be produced by varying the DIW technique. The micromorphology test results show that the samples sintered at 1150°C for 2 h formed ceramics with a set amount of pores, which benefit cell growth by providing more locations for cells to attach and proliferate. Under a microscope, the proliferations of human liver carcinoma cell line (HepG2) cells can be observed on the 3D HAp scaffolds. The DIW method has the advantages of a rapid process, ease of design and high precision control, potentially inspiring the design and application of biomaterials and scaffolds.

  17. Low-Temperature Additive Manufacturing of Biomimic Three-Dimensional Hydroxyapatite/Collagen Scaffolds for Bone Regeneration.

    PubMed

    Lin, Kai-Feng; He, Shu; Song, Yue; Wang, Chun-Mei; Gao, Yi; Li, Jun-Qin; Tang, Peng; Wang, Zheng; Bi, Long; Pei, Guo-Xian

    2016-03-23

    Low-temperature additive manufacturing (AM) holds promise for fabrication of three-dimensional (3D) scaffolds containing bioactive molecules and/or drugs. Due to the strict technical limitations of current approaches, few materials are suitable for printing at low temperature. Here, a low-temperature robocasting method was employed to print biomimic 3D scaffolds for bone regeneration using a routine collagen-hydroxyapatite (CHA) composite material, which is too viscous to be printed via normal 3D printing methods at low temperature. The CHA scaffolds had excellent 3D structure and maintained most raw material properties after printing. Compared to nonprinted scaffolds, printed scaffolds promoted bone marrow stromal cell proliferation and improved osteogenic outcome in vitro. In a rabbit femoral condyle defect model, the interconnecting pores within the printed scaffolds facilitated cell penetration and mineralization before the scaffolds degraded and enhanced repair, compared to nonprinted CHA scaffolds. Additionally, the optimal printing parameters for 3D CHA scaffolds were investigated; 600-μm-diameter rods were optimal in terms of moderate mechanical strength and better repair outcome in vivo. This low-temperature robocasting method could enable a variety of bioactive molecules to be incorporated into printed CHA materials and provides a method of bioprinting biomaterials without compromising their natural properties.

  18. 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

  19. A review: fabrication of porous polyurethane scaffolds.

    PubMed

    Janik, H; Marzec, M

    2015-03-01

    The aim of tissue engineering is the fabrication of three-dimensional scaffolds that can be used for the reconstruction and regeneration of damaged or deformed tissues and organs. A wide variety of techniques have been developed to create either fibrous or porous scaffolds from polymers, metals, composite materials and ceramics. However, the most promising materials are biodegradable polymers due to their comprehensive mechanical properties, ability to control the rate of degradation and similarities to natural tissue structures. Polyurethanes (PUs) are attractive candidates for scaffold fabrication, since they are biocompatible, and have excellent mechanical properties and mechanical flexibility. PU can be applied to various methods of porous scaffold fabrication, among which are solvent casting/particulate leaching, thermally induced phase separation, gas foaming, emulsion freeze-drying and melt moulding. Scaffold properties obtained by these techniques, including pore size, interconnectivity and total porosity, all depend on the thermal processing parameters, and the porogen agent and solvents used. In this review, various polyurethane systems for scaffolds are discussed, as well as methods of fabrication, including the latest developments, and their advantages and disadvantages.

  20. Rapid prototyping amphiphilic polymer/hydroxyapatite composite scaffolds with hydration-induced self-fixation behavior.

    PubMed

    Kutikov, Artem B; Gurijala, Anvesh; Song, Jie

    2015-03-01

    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

  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. Functionalization of polycaprolactone/hydroxyapatite scaffolds with Usnea lethariiformis extract by using supercritical CO2.

    PubMed

    Fanovich, M A; Ivanovic, J; Zizovic, I; Misic, D; Jaeger, P

    2016-01-01

    Investigation of an integrated supercritical fluid extraction and supercritical solvent impregnation process for fabrication of microporous polycaprolactone-hydroxyapatite (PCL-HA) scaffolds with antibacterial activity is presented. The HA content and particle size as well as the operating conditions of the integrated process is optimized regarding the amount of impregnated antibacterial agent (Usnea lethariiformis extract) in the PCL-HA matrix, scaffold morphology and antibacterial activity against methicillin resistant Staphylococcus aureus (MRSA) strains. High pressure differential scanning calorimetry (HP-DSC) assay reveals that an increasing amount of HA results in decreasing melting temperature as well as crystallinity at an operating pressure of 17 MPa. The PCL-HA composites with micrometric sizes of the HA particles are convenient for being processed by the integrated process due to the simple preparation, a good interaction between the PCL matrix and filler and the advantageous impact on sorption. The scaffold obtained from PCL-HA with 20% of the HA shows the highest impregnation yield at 17 MPa and 35 °C (5.9%) and subsequently also the best bactericidal effect on the tested MRSA strains at an initial bacterial inoculum of 2 × 10(-4)CFU/mL. PMID:26478304

  3. Hydroxyapatite/regenerated silk fibroin scaffold-enhanced osteoinductivity and osteoconductivity of bone marrow-derived mesenchymal stromal cells.

    PubMed

    Jiang, Jia; Hao, Wei; Li, Yuzhuo; Yao, Jinrong; Shao, Zhengzhong; Li, Hong; Yang, Jianjun; Chen, Shiyi

    2013-04-01

    A novel hydroxyapatite/regenerated silk fibroin scaffold was prepared and investigated for its potential to enhance both osteoinductivity and osteoconductivity of bone marrow-derived mesenchymal stromal cells in vitro. Approx. 12.4 ± 0.06 % (w/w) hydroxyapatite was deposited onto the scaffold, and cell viability and DNA content were significantly increased (18.5 ± 0.6 and 33 ± 1.2 %, respectively) compared with the hydroxyapatite scaffold after 14 days. Furthermore, alkaline phosphatase activity in the novel scaffold increased 41 ± 2.5 % after 14 days compared with the hydroxyapatite scaffold. The data indicate that this novel hydroxyapatite/regenerated silk fibroin scaffold has a positive effect on osteoinductivity and osteoconductivity, and may be useful for bone tissue engineering.

  4. 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

  5. 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.

  6. Polyurethane/fluor-hydroxyapatite nanocomposite scaffolds for bone tissue engineering. Part I: morphological, physical, and mechanical characterization.

    PubMed

    Asefnejad, Azadeh; Behnamghader, Aliasghar; Khorasani, Mohammad Taghi; Farsadzadeh, Babak

    2011-01-01

    In this study, new nano-fluor-hydroxyapatite (nFHA)/polyurethane composite scaffolds were fabricated for potential use in bone tissue engineering. Polyester urethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and 1,4-butanediol as chain extender. Nano fluor-hydroxyapatite (nFHA) was successfully synthesized by sol-gel method. The solid-liquid phase separation and solvent sublimation methods were used for preparation of the porous composites. Mechanical properties, chemical structure, and morphological characteristics of the samples were investigated by compressive test, Fourier transform infrared, and scanning electron microscopy (SEM) techniques, respectively. The effect of nFHA powder content on porosity and pore morphology was investigated. SEM images demonstrated that the scaffolds were constituted of interconnected and homogeneously distributed pores. The pore size of the scaffolds was in the range 50-250 μm. The result obtained in this research revealed that the porosity and pore average size decreased and compressive modulus increased with nFHA percentage. Considering morphological, physical, and mechanical properties, the scaffold with a higher ratio of nFHA has suitable potential use in tissue regeneration.

  7. A novel porous bioceramics scaffold by accumulating hydroxyapatite spherules for large bone tissue engineering in vivo. I. Preparation and characterization of scaffold.

    PubMed

    Peng, Qian; Jiang, Faxing; Huang, Peng; Zhou, Shaobing; Weng, Jie; Bao, Chongyun; Zhang, Cong; Yu, Haiyang

    2010-06-01

    A novel scaffold with large dimension of 3-4 cm in length and 1-1.5 cm in diameter was designed and fabricated for engineering large bone tissue in vivo. The scaffold was constructed by filling hydroxyapatite (HA) spherules into a porous HA tube. The HA spherules were prepared by chitin sol emulsification in oil and gelation in situ, and their sizes can be controlled by parameters such as stirring rate and oil temperature. Accumulation of the HA spherules formed the interconnected pores in the scaffold, and the porosity and microstructure of the scaffold can be controlled by varying the size and miroporous structure of the HA spherules. Porous HA tube coated with a thin layer of poly(L-lactic acid) (PLA) held the HA spherules together and provided the initial strength of scaffolds. HA spherules can be easily compounded with biological substance, such as comminuted bone granules, before being filled into the HA tubes. A pilot study is underway to use the hybrid scaffolds at different sites such as muscle, peritoneum, and bone side. PMID:19708076

  8. Preparation and characterization of bionic bone structure chitosan/hydroxyapatite scaffold for bone tissue engineering.

    PubMed

    Zhang, Jiazhen; Nie, Jingyi; Zhang, Qirong; Li, Youliang; Wang, Zhengke; Hu, Qiaoling

    2014-01-01

    Three-dimensional oriented chitosan (CS)/hydroxyapatite (HA) scaffolds were prepared via in situ precipitation method in this research. Scanning electron microscopy (SEM) images indicated that the scaffolds with acicular nano-HA had the spoke-like, multilayer and porous structure. The SEM of osteoblasts which were polygonal or spindle-shaped on the composite scaffolds after seven-day cell culture showed that the cells grew, adhered, and spread well. The results of X-ray powder diffractometer and Fourier transform infrared spectrometer showed that the mineral particles deposited in the scaffold had phase structure similar to natural bone and confirmed that particles were exactly HA. In vitro biocompatibility evaluation indicated the composite scaffolds showed a higher degree of proliferation of MC3T3-E1 cell compared with the pure CS scaffolds and the CS/HA10 scaffold was the highest one. The CS/HA scaffold also had a higher ratio of adhesion and alkaline phosphate activity value of osteoblasts compared with the pure CS scaffold, and the ratio increased with the increase of HA content. The ALP activity value of composite scaffolds was at least six times of the pure CS scaffolds. The results suggested that the composite scaffolds possessed good biocompatibility. The compressive strength of CS/HA15 increased by 33.07% compared with the pure CS scaffold. This novel porous scaffold with three-dimensional oriented structure might have a potential application in bone tissue engineering.

  9. Effect of doping in carbon nanotubes on the viability of biomimetic chitosan-carbon nanotubes-hydroxyapatite scaffolds.

    PubMed

    Fonseca-García, Abril; Mota-Morales, Josué D; Quintero-Ortega, Iraís A; García-Carvajal, Zaira Y; Martínez-López, V; Ruvalcaba, Erika; Landa-Solís, Carlos; Solis, Lilia; Ibarra, Clemente; Gutiérrez, María C; Terrones, Mauricio; Sanchez, Isaac C; del Monte, Francisco; Velasquillo, María C; Luna-Bárcenas, G

    2014-10-01

    This work describes the preparation and characterization of biomimetic chitosan/multiwall carbon nanotubes/nano-hydroxyapatite (CTS/MWCNT/nHAp) scaffolds and their viability for bone tissue engineering applications. The cryogenic process ice segregation-induced self-assembly (ISISA) was used to fabricate 3D biomimetic CTS scaffolds. Proper combination of cryogenics, freeze-drying, nature and molecular ratio of solutes give rise to 3D porous interconnected scaffolds with clusters of nHAp distributed along the scaffold surface. The effect of doping in CNT (e.g. with oxygen and nitrogen atoms) on cell viability was tested. Under the same processing conditions, pore size was in the range of 20-150 μm and irrespective on the type of CNT. Studies on cell viability with scaffolds were carried out using human cells from periosteum biopsy. Prior to cell seeding, the immunophenotype of mesenchymal periosteum or periosteum-derived stem cells (MSCs-PCs) was characterized by flow cytometric analysis using fluorescence-activated and characteristic cell surface markers for MSCs-PCs. The characterized MSCs-PCs maintained their periosteal potential in cell cultures until the 2nd passage from primary cell culture. Thus, the biomimetic CTS/MWCNT/nHAp scaffolds demonstrated good biocompatibility and cell viability in all cases such that it can be considered as promising biomaterials for bone tissue engineering. PMID:23894015

  10. Solvent-free polymer/bioceramic scaffolds for bone tissue engineering: fabrication, analysis, and cell growth.

    PubMed

    Minton, Joshua; Janney, Cara; Akbarzadeh, Rosa; Focke, Carlie; Subramanian, Aswati; Smith, Tyler; McKinney, Joseph; Liu, Junyi; Schmitz, James; James, Paul F; Yousefi, Azizeh-Mitra

    2014-01-01

    This study examines the potential use of porous polycaprolactone (PCL) and polycaprolocatone/hydroxyapatite (PCL/HA) scaffolds fabricated through melt molding and porogen leaching for bone tissue engineering. While eliminating organic solvents is desirable, the process steps proposed in this study for uniformly dispersing HA particles (~5 μm in size) within the scaffold can also contribute to homogeneous properties for these porous composites. Poly(ethylene oxide) (PEO) was chosen as a porogen due to its similar density and melting point as PCL. Pore size of the scaffold was controlled by limiting the size of PCL and PEO particles used in fabrication. The percent of HA in the fabricated scaffolds was quantified by thermogravimetric analysis (TGA). Mechanical testing was used to compare the modulus of the scaffolds to that of bone, and the pore size distribution was examined with microcomputed tomography (μCT). Scanning electron microscopy (SEM) was used to examine the effect on scaffold morphology caused by the addition of HA particles. Both μCT and SEM results showed that HA could be incorporated into PCL scaffolds without negatively affecting scaffold morphology or pore formation. Energy-dispersive X-ray spectroscopy (EDS) and elemental mapping demonstrated a uniform distribution of HA within PCL/HA scaffolds. Murine calvaria-derived MC3T3-E1 cells were used to determine whether cells could attach on scaffolds and grow for up to 21 days. SEM images revealed an increase in cell attachment with the incorporation of HA into the scaffolds. Similarly, DNA content analysis showed a higher cell adhesion to PCL/HA scaffolds.

  11. Migration of co-cultured endothelial cells and osteoblasts in composite hydroxyapatite/polylactic acid scaffolds.

    PubMed

    Shah, Amita R; Shah, Sarita R; Oh, Sunho; Ong, Joo L; Wenke, Joseph C; Agrawal, C Mauli

    2011-10-01

    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 experiment, 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.

  12. Development of Microspheres Covered with Hydroxyapatite Nanocrystals as Cell Scaffold for Angiogenesis

    NASA Astrophysics Data System (ADS)

    Iwamoto, Takashi; Terada, Takahiro; Kogai, Yasumichi; Okada, Masahiro; Fujii, Syuji; Furuzono, Tsutomu

    2012-06-01

    We prepared poly(L-lactide-co-glycolide) cell scaffolds coated with hydroxyapatite (HAp) nanocrystals with 50-100 nm in diameter via the Pickering emulsion method. Our cell scaffolds were composed of biodegradable polymers and HAp nanocrystals as a core and shell, respectively. The scaffolds were spherical but displayed uneven shapes when altering a shear speed of homogenization during syntheses. The surface coverage of HAp nanocrystals was examined because the HAp-coating ratio for the scaffolds was an important factor as cell scaffolds in order to enhance cell adhesion. On the basis of scanning electron microscopy observations and thermogravimetric analyses, it was found that the cell scaffolds showed distorted morphologies, and the HAp-coating ratio decreased with increasing the shear speed in the synthesis because shear stress influenced shapes of the scaffolds.

  13. Direct Scaffolding of Biomimetic Hydroxyapatite-gelatin Nanocomposites using Aminosilane Cross-linker for Bone Regeneration

    PubMed Central

    Chiu, Chi-Kai; Ferreira, Joao; Luo, Tzy-Jiun M.; Geng, Haixia; Lin, Feng-Chang; Ko, Ching-Chang

    2012-01-01

    Hydroxyapatite-gelatin modified siloxane (GEMOSIL) nanocomposite was developed by coating, kneading and hardening processes to provide formable scaffolding for alloplastic graft applications. The present study aims to characterize scaffolding formability and mechanical properties of GEMOSIL, and to test the in vitro and in vivo biocompatibility of GEMOSIL. Buffer Solution initiated formable paste followed by the sol-gel reaction led to a final hardened composite. Results showed the adequate coating of aminosilane, 11–19 wt%, affected the cohesiveness of the powders and the final compressive strength (69 MPa) of the composite. TGA and TEM results showed the effective aminosilane coating that preserves hydroxyapatite-gelatin nanocrystals from damage. Both GEMOSIL with and without titania increased the mineralization of preosteoblasts in vitro. Only did titania additives revealed good in vivo bone formation in rat calvarium defects. The scaffolding formability, due to cohesive bonding among GEMOSIL particles, could be further refined to fulfill the complicated scaffold processes. PMID:22669282

  14. Bone regeneration of hydroxyapatite/alumina bilayered scaffold with 3 mm passage-like medullary canal in canine tibia model.

    PubMed

    Kim, Jong Min; Son, Jun Sik; Kang, Seong Soo; Kim, Gonhyung; Choi, Seok Hwa

    2015-01-01

    The aim of this study was to evaluate the bone regeneration of hydroxyapatite (HA)/alumina bilayered scaffold with a 3 mm passage-like medullary canal in a beagle tibia model. A porous HA/alumina scaffold was fabricated using a polymeric template-coating technique. HA/alumina scaffold dimensions were 10 mm in outer diameter, 20 mm in length, and with either a 3 mm passage or no passage. A 20 mm segmental defect was induced using an oscillating saw through the diaphysis of the beagle tibia. The defects of six beagles were filled with HA/alumina bilayered scaffolds with a 3 mm passage or without. The segmental defect was fixated using one bone plate and six screws. Bone regeneration within the HA/alumina scaffolds was observed at eight weeks after implantation. The evaluation of bone regeneration within the scaffolds after implantation in a beagle tibia was performed using radiography, computerized tomography (CT), micro-CT, and fluorescence microscopy. New bone successfully formed in the tibia defects treated with 3 mm passage HA/alumina scaffolds compared to without-passage HA/alumina scaffolds. It was concluded that the HA/alumina bilayered scaffold with 3 mm passage-like medullary canal was instrumental in inducing host-scaffold engraftment of the defect as well as distributing the newly formed bone throughout the scaffold at 8 weeks after implantation. PMID:25688353

  15. 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

  16. Biocomposite scaffolds based on electrospun poly(3-hydroxybutyrate) nanofibers and electrosprayed hydroxyapatite nanoparticles for bone tissue engineering applications.

    PubMed

    Ramier, Julien; Bouderlique, Thibault; Stoilova, Olya; Manolova, Nevena; Rashkov, Iliya; Langlois, Valérie; Renard, Estelle; Albanese, Patricia; Grande, Daniel

    2014-05-01

    The electrospinning technique combined with the electrospraying process provides a straightforward and versatile approach for the fabrication of novel nanofibrous biocomposite scaffolds with structural, mechanical, and biological properties potentially suitable for bone tissue regeneration. In this comparative investigation, three types of poly(3-hydroxybutyrate) (PHB)-based scaffolds were engineered: (i) PHB mats by electrospinning of a PHB solution, (ii) mats of PHB/hydroxyapatite nanoparticle (nHA) blends by electrospinning of a mixed solution containing PHB and nHAs, and (iii) mats constituted of PHB nanofibers and nHAs by simultaneous electrospinning of a PHB solution and electrospraying of a nHA dispersion. Scaffolds based on PHB/nHA blends displayed improved mechanical properties compared to those of neat PHB mats, due to the incorporation of nHAs within the fibers. The electrospinning/electrospraying approach afforded biocomposite scaffolds with lower mechanical properties, due to their higher porosity, but they displayed slightly better biological properties. In the latter case, the bioceramic, i.e. nHAs, largely covered the fiber surface, thus allowing for a direct exposure to cells. The 21 day-monitoring through the use of MTS assays and SEM analyses demonstrated that human mesenchymal stromal cells (hMSCs) remained viable on PHB/nHA biocomposite scaffolds and proliferated continuously until reaching confluence. PMID:24656364

  17. Fabrication of titania/hydroxyapatite composite granules for photo-catalyst

    SciTech Connect

    Ji Shidong Murakami, Setsuaki; Kamitakahara, Masanobu; Ioku, Koji

    2009-04-02

    The titania/hydroxyapatite composite granular photo-catalyst with novel microstructure was fabricated by the process based on the liquid immiscibility effect and followed by precalcination and hydrothermal treatment from commercially available powders of {alpha}-Tri-calcium phosphate and TiO{sub 2}. XRD, SEM, BET, optical microscopy and UV-vis spectrophotometer were applied to characterize the prepared photo-catalyst. Microstructure analysis indicated that the granule was weaved by rod-shaped hydroxyapatite crystals whose surface was covered by nano-sized TiO{sub 2}. In the composite granules, the active surface of anatase was retained effectively. With the hybridization of TiO{sub 2} and HAp, a 16-nm blue-shift of absorption edge could be observed and the crystallinity of anatase could be enhanced by precalcination. The granules with the rod-shaped hydroxyapatite crystals performing as scaffold work as three-dimensional high porous, size-controllable small reactor. The phase and microstructure transformation of the granule before and after hydrothermal treatment was investigated and its decomposition ability was evaluated by using Methylene blue as a target pollutant compound.

  18. Biomimetic Collagen–Hydroxyapatite Composite Fabricated via a Novel Perfusion-Flow Mineralization Technique

    PubMed Central

    Antebi, Ben; Cheng, Xingguo; Harris, Jeffrey N.; Gower, Laurie B.; Chen, Xiao-Dong

    2013-01-01

    Prevalent three-dimensional scaffolds for bone tissue engineering are mineralized collagen–hydroxyapatite (Col/HA) composites. Conventional mineralization techniques are either to coat collagen scaffold surfaces with minerals or to simply mix collagen and mineral nanoparticles together. These conventional in vitro collagen mineralization methods are different from the in vivo bone formation process and often result in scaffolds that are not suitable for bone tissue engineering. In this study, a unique perfusion-flow (i.e., dynamic) in conjunction with a previously described polymer-induced liquid-precursor (PILP) method was used to fabricate a porous Col/HA composite. The dynamic flow emulated the physiological extracellular fluid flow containing the mineralization ions, while the PILP method facilitated the deposition of the HA crystals within the collagen fibrils (i.e., intrafibrillar mineralization). By utilizing a dynamic PILP technique to mimic the in vivo bone formation process, the resultant Col/HA composite has a similar structure and compositions like human trabecular bone. A comparison of the dynamic and static mineralization methods revealed that the novel dynamic technique facilitates more efficient and homogenous mineral deposition throughout the Col/HA composite. The dynamic intrafibrillar mineralization method generated stiff Col/HA composites with excellent surface property for cell attachment and growth. The human mesenchymal stem cells cultured on the Col/HA composites quickly remodeled the scaffolds and resulted in constructs with an extensive cell-derived extracellular matrix network. PMID:23157544

  19. Biomimetic collagen-hydroxyapatite composite fabricated via a novel perfusion-flow mineralization technique.

    PubMed

    Antebi, Ben; Cheng, Xingguo; Harris, Jeffrey N; Gower, Laurie B; Chen, Xiao-Dong; Ling, Jian

    2013-07-01

    Prevalent three-dimensional scaffolds for bone tissue engineering are mineralized collagen-hydroxyapatite (Col/HA) composites. Conventional mineralization techniques are either to coat collagen scaffold surfaces with minerals or to simply mix collagen and mineral nanoparticles together. These conventional in vitro collagen mineralization methods are different from the in vivo bone formation process and often result in scaffolds that are not suitable for bone tissue engineering. In this study, a unique perfusion-flow (i.e., dynamic) in conjunction with a previously described polymer-induced liquid-precursor (PILP) method was used to fabricate a porous Col/HA composite. The dynamic flow emulated the physiological extracellular fluid flow containing the mineralization ions, while the PILP method facilitated the deposition of the HA crystals within the collagen fibrils (i.e., intrafibrillar mineralization). By utilizing a dynamic PILP technique to mimic the in vivo bone formation process, the resultant Col/HA composite has a similar structure and compositions like human trabecular bone. A comparison of the dynamic and static mineralization methods revealed that the novel dynamic technique facilitates more efficient and homogenous mineral deposition throughout the Col/HA composite. The dynamic intrafibrillar mineralization method generated stiff Col/HA composites with excellent surface property for cell attachment and growth. The human mesenchymal stem cells cultured on the Col/HA composites quickly remodeled the scaffolds and resulted in constructs with an extensive cell-derived extracellular matrix network.

  20. 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.

  1. Porous bioactive scaffold of aliphatic polyurethane and hydroxyapatite for tissue regeneration.

    PubMed

    Wang, Li; Li, Yubao; Zuo, Yi; Zhang, Li; Zou, Qin; Cheng, Lin; Jiang, Hong

    2009-04-01

    In this study, a new hydroxyapatite (HA)/polyurethane (PU) composite porous scaffold was developed by in situ polymerization. Aliphatic isophorone diisocyanate as a nontoxic and safe agent was adopted to produce the rigid segment in polyurethane polymerization. Hydroxyapatite powder was compounded in a PU polymer matrix during the polymeric process. The macrostructure and morphology as well as mechanical strength of the scaffolds were characterized by FTIR, XRD, DSC and SEM. The results show that the isophorone diisocyanate can react mildly with hydroxyl (-OH) groups of castor oil and a mild foaming action caused by the release of CO2 gas occurred simultaneously in the reactive process, thus producing a uniform porous structure of HA/PU scaffold. The HA/PU composite scaffold with a high HA content of about 60 wt% has a porosity of more than 78% and a pore size from 100 microm to 800 microm. The HA/PU scaffold exhibited good cytocompatibility estimated by co-culturing the scaffold with MG63 cells through MTT test. The porous composite scaffold has good homogenization and a perfect three-dimensional structure for cell migration and bone tissue ingrowth, and should have good prospects for bone tissue regeneration. PMID:19208942

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

    PubMed Central

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

    2015-01-01

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

  3. Biologically inspired growth of hydroxyapatite crystals on bio-organics-defined scaffolds

    SciTech Connect

    Yang, Chunrong; Li, Yuli; Nan, Kaihui

    2013-03-15

    Graphical abstract: Petal-like crystals were observed to form on the surface of the BG/COL/ChS scaffolds. Highlights: ► Porous scaffolds were prepared using bioglass, collagen and chondroitin sulfate. ► Highly oriented HA crystals were grown on scaffolds using simulated body fluids ► The microstructure and orientation of HA were explained by molecular configuration. - Abstract: Several bio-organics-defined composite scaffolds were prepared using 58s-bioglass (BG), collagen (Col) and chondroitin sulfate (ChS). These scaffolds possess highly porous structure. X-ray diffraction of these scaffolds strongly indicated that hydroxyapatite (HA) crystals formed on their surfaces in simulated body fluids within 3 d, and similar formation process of crystals could be obtained on BG/Col and BG/Col/ChS scaffolds. The morphology and structure of the crystals were further examined by scanning electron microscopy. The results obtained indicate that an apatite with petal-like structure similar to that found on BG/Col scaffolds can be produced on BG/Col/ChS scaffolds through biomimetic synthesis, while that on BG/ChS scaffolds took place differently. The differences could be explained by self-assembly processes and the different macromolecular configurations of the Col and ChS fibrils which self-assemble spontaneously into their fibers. On the other hand, the bio-organics-defined composites have good cell biocompability. The results may be applicable to develop tailored biomaterials for peculiar bone substitute.

  4. Bone response to 3-D periodic hydroxyapatite scaffolds with and without tailored microporosity to deliver bone morphogenetic protein 2.

    SciTech Connect

    Eurell, Jo Ann; Dellinger, Jennifer Gwynne; Cesarano, Joseph, III; Jamison, Russell D.

    2005-06-01

    The in vivo bone response of 3D periodic hydroxyapatite (HA) scaffolds is investigated. Two groups of HA scaffolds (11 mm diameter x 3.5 mm thick) are fabricated by direct-write assembly of a concentrated HA ink. The scaffolds consist of cylindrical rods periodically arranged into four quadrants with varying separation distances between rods. In the first group, HA rods (250 {micro}m in diameter) are patterned to create pore channels, whose areal dimensions are 250 x 250 {micro}m{sup 2} in quadrant 1, 250 x 500 {micro}m{sup 2} in quadrants 2 and 4, and 500 x 500 {micro}m{sup 2} in quadrant 3. In the second group, HA rods (400 {micro}m in diameter) are patterned to create pore channels, whose areal dimensions of 500 x 500 {micro}m{sup 2} in quadrant 1, 500 x 750 {micro}m{sup 2} in quadrants 2 and 4, and 750 x 750 {micro}m{sup 2} in quadrant 3. Each group of scaffolds is partially densified by sintering at 1200 C prior to being implanted bilaterally in trephine defects of skeletally mature New Zealand White rabbits. Their tissue response is evaluated at 8 and 16 weeks using micro-computed tomography, histology, and scanning electron microscopy. New trabecular bone is conducted rapidly and efficiently across substantial distances within these patterned 3D HA scaffolds. Our observations suggest that HA rods are first coated with a layer of new bone followed by subsequent scaffold infilling via outward and inward radial growth of the coated regions. Direct-write assembly of 3D periodic scaffolds composed of micro-porous HA rods arrayed to produce macro-pores that are size-matched to trabecular bone may represent an optimal strategy for bone repair and replacement structures.

  5. Fabrication of multi-biofunctional gelatin-based electrospun fibrous scaffolds for enhancement of osteogenesis of mesenchymal stem cells.

    PubMed

    Lin, Wei-Han; Yu, Jiashing; Chen, Guoping; Tsai, Wei-Bor

    2016-02-01

    Biofunctional scaffolds that support the adhesion, proliferation, and osteo-differentiation of mesenchymal stem cells (MSCs) are critical for bone tissue engineering. In this study, a simple in situ UV-crosslinking strategy was utilized to fabricate gelatin electrospun fibrous (GEF) scaffolds with multiple biosignals, including cell adhesive Arg-Gly-Asp (RGD) peptide, osteo-conductive hydroxyapatite (HAp) nanoparticles, and osteo-inductive bone morphogenic protein-2 (BMP-2). The adhesion and proliferation of MSCs on the GEF scaffolds were improved by the incorporation of RGD. Meanwhile, the incorporation of HAp and BMP-2 enhanced osteo-differentiation of MSCs. The three incorporated bio-factors exert a synergistic effect on osteogenesis of MSCs in the GEF scaffolds. This strategy of incorporating multiple biomolecules could be used to fabricate crosslinked electrospun scaffolds of natural polymers for tissue-engineering applications.

  6. Fabrication of multi-biofunctional gelatin-based electrospun fibrous scaffolds for enhancement of osteogenesis of mesenchymal stem cells.

    PubMed

    Lin, Wei-Han; Yu, Jiashing; Chen, Guoping; Tsai, Wei-Bor

    2016-02-01

    Biofunctional scaffolds that support the adhesion, proliferation, and osteo-differentiation of mesenchymal stem cells (MSCs) are critical for bone tissue engineering. In this study, a simple in situ UV-crosslinking strategy was utilized to fabricate gelatin electrospun fibrous (GEF) scaffolds with multiple biosignals, including cell adhesive Arg-Gly-Asp (RGD) peptide, osteo-conductive hydroxyapatite (HAp) nanoparticles, and osteo-inductive bone morphogenic protein-2 (BMP-2). The adhesion and proliferation of MSCs on the GEF scaffolds were improved by the incorporation of RGD. Meanwhile, the incorporation of HAp and BMP-2 enhanced osteo-differentiation of MSCs. The three incorporated bio-factors exert a synergistic effect on osteogenesis of MSCs in the GEF scaffolds. This strategy of incorporating multiple biomolecules could be used to fabricate crosslinked electrospun scaffolds of natural polymers for tissue-engineering applications. PMID:26642073

  7. Vaporizable Scaffolds for Fabricating Thermoelectric Modules

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeffrey; Yen, Shiao-pin; Fleurial, Jean-Pierre; Paik, Jong-Ah

    2006-01-01

    A process for fabricating thermoelectric modules with vacuum gaps separating the thermoelectric legs has been conceived, and the feasibility of some essential parts of the process has been demonstrated. The vacuum gaps are needed to electrically insulate the legs from each other. The process involves the use of scaffolding in the form of sheets of a polymer to temporarily separate the legs by the desired distance, which is typically about 0.5 mm. During a bonding subprocess that would take place in a partial vacuum at an elevated temperature, the polymer would be vaporized, thereby creating the vacuum gaps.

  8. Improved in vitro biocompatibility of surface-modified hydroxyapatite sponge scaffold with gelatin and BMP-2 in comparison against a commercial bone allograft.

    PubMed

    Carpena, Nathaniel T; Min, Young-Ki; Lee, Byong-Taek

    2015-01-01

    This study aims to demonstrate the morphology and in vitro biocompatibility of neat and surface-modified hydroxyapatite sponge scaffold (SM-HASS) which was fabricated using a sponge replica method, and compared with the commercially available demineralized freeze-dried bone allograft (DFDBA). Surface-modifications were done by coating the surface area of the neat hydroxyapatite sponge scaffold (HASS) with either gelatin alone (HASS/G) or gelatin and BMP-2 growth factor (HASS/G+B). Scanning electron microscope (SEM), Fourier transform infrared (FTIR), porosity, pore size distribution, and compressive strength analyses showed that the addition of gelatin in HASS/G produced a morphologically and structurally similar scaffold to that of the allograft. The addition of BMP-2 improved the biocompatibility of the HASS/G+B in vitro using MC3T3-E1 cells which showed better cell viability, proliferation, and cell adhesion than on the allograft. Therefore, hydroxyapatite scaffold coated with gelatin polymer and gelatin with BMP-2 growth factor showed comparable performance against commercially available DFDBA from cadaver with regards to structure and in vitro biocompatibility.

  9. Directing osteogenesis of stem cells with hydroxyapatite precipitated electrospun eri-tasar silk fibroin nanofibrous scaffold.

    PubMed

    Panda, N; Bissoyi, A; Pramanik, K; Biswas, A

    2014-01-01

    Stimulating stem cell differentiation without growth factor supplement offers a potent and cost-effective scaffold for tissue regeneration. We hypothesise that surface precipitation of nano-hydroxyapatite (nHAp) over blends of non-mulberry silk fibroin with better hydrophilicity and RGD amino acid sequences can direct the stem cell towards osteogenesis. This report focuses on the fabrication of a blended eri-tasar silk fibroin nanofibrous scaffold (ET) followed by nHAp deposition by a surface precipitation (alternate soaking in calcium and phosphate solution) method. Morphology, hydrophilicity, composition, and the thermal and mechanical properties of ET/nHAp were examined by field emission scanning electron microscopy, TEM, FT-IR, X-ray diffraction, TGA and contact angle measurement and compared with ET. The composite scaffold demonstrated improved thermal stability and surface hydrophilicity with an increase in stiffness and elastic modulus (778 ± 2.4 N/m and 13.1 ± 0.36 MPa) as compared to ET (160.6 ± 1.34 N/m and 8.3 ± 0.4 MPa). Mineralisation studies revealed an enhanced and more uniform surface deposition of HAp-like crystals, while significant differences in cellular viability and attachment were observed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and confocal microscopy study. The cell viability and expression of adhesion molecules (CD 44 and CD 29) are found to be optimum for subsequent stages of growth proliferation and differentiation. The rates of proliferation have been observed to decrease owing to the transition of MSC from a state of proliferation to a state of differentiation. The confirmation of improved osteogenic differentiation was finally verified through the alkaline phosphatase assay, pattern of gene expression related to osteogenic differentiation and morphological observations of differentiated cord blood human mesenchymal stem cells under fluorescence microscope. The results

  10. Precision Extruding Deposition for Freeform Fabrication of PCL and PCL-HA Tissue Scaffolds

    NASA Astrophysics Data System (ADS)

    Shor, L.; Yildirim, E. D.; Güçeri, S.; Sun, W.

    Computer-aided tissue engineering approach was used to develop a novel Precision Extrusion Deposition (PED) process to directly fabricate Polycaprolactone (PCL) and composite PCL/Hydroxyapatite (PCL-HA) tissue scaffolds. The process optimization was carried out to fabricate both PCL and PCL-HA (25% concentration by weight of HA) with a controlled pore size and internal pore structure of the 0°/90° pattern. Two groups of scaffolds having 60 and 70% porosity and with pore sizes of 450 and 750 microns, respectively, were evaluated for their morphology and compressive properties using Scanning Electron Microscopy (SEM) and mechanical testing. The surface modification with plasma was conducted on PCL scaffold to increase the cellular attachment and proliferation. Our results suggested that inclusion of HA significantly increased the compressive modulus from 59 to 84 MPa for 60% porous scaffolds and from 30 to 76 MPa for 70% porous scaffolds. In vitro cell-scaffolds interaction study was carried out using primary fetal bovine osteoblasts to assess the feasibility of scaffolds for bone tissue engineering application. In addition, the results in surface hydrophilicity and roughness show that plasma surface modification can increase the hydrophilicity while introducing the nano-scale surface roughness on PCL surface. The cell proliferation and differentiation were calculated by Alamar Blue assay and by determining alkaline phosphatase activity. The osteoblasts were able to migrate and proliferate over the cultured time for both PCL as well as PCL-HA scaffolds. Our study demonstrated the viability of the PED process to the fabricate PCL and PCL-HA composite scaffolds having necessary mechanical property, structural integrity, controlled pore size and pore interconnectivity desired for bone tissue engineering.

  11. Three-dimensional printed PCL-hydroxyapatite scaffolds filled with CNTs for bone cell growth stimulation.

    PubMed

    Gonçalves, Elsa M; Oliveira, Filipe J; Silva, Rui F; Neto, Miguel A; Fernandes, M Helena; Amaral, Margarida; Vallet-Regí, María; Vila, Mercedes

    2016-08-01

    A three-phase [nanocrystalline hydroxyapatite (HA), carbon nanotubes (CNT), mixed in a polymeric matrix of polycaprolactone (PCL)] composite scaffold produced by 3D printing is presented. The CNT content varied between 0 and 10 wt % in a 50 wt % PCL matrix, with HA being the balance. With the combination of three well-known materials, these scaffolds aimed at bringing together the properties of all into a unique material to be used in tissue engineering as support for cell growth. The 3D printing technique allows producing composite scaffolds having an interconnected network of square pores in the range of 450-700 μm. The 2 wt % CNT scaffold offers the best combination of mechanical behaviour and electrical conductivity. Its compressive strength of ∼4 MPa is compatible with the trabecular bone. The composites show typical hydroxyapatite bioactivity, good cell adhesion and spreading at the scaffolds surface, this combination of properties indicating that the produced 3D, three-phase, scaffolds are promising materials in the field of bone regenerative medicine. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1210-1219, 2016. PMID:26089195

  12. In-situ hardening hydroxyapatite-based scaffold for bone repair.

    PubMed

    Zhang, Yu; Xu, Hockin H K; Takagi, Shozo; Chow, Laurence C

    2006-05-01

    Musculoskeletal conditions are becoming a major health concern because of an aging population and sports- and traffic-related injuries. While sintered hydroxyapatite implants require machining, calcium phosphate cement (CPC) bone repair material is moldable, self-hardens in situ, and has excellent osteoconductivity. In the present work, new approaches for developing strong and macroporous scaffolds of CPC were tested. Relationships were determined between scaffold porosity and strength, elastic modulus and fracture toughness. A biocompatible and biodegradable polymer (chitosan) and a water-soluble porogen (mannitol) were incorporated into CPC: Chitosan to make the material stronger, fast-setting and anti-washout; and mannitol to create macropores. Flexural strength, elastic modulus, and fracture toughness were measured as functions of mannitol mass fraction in CPC from 0% to 75%. After mannitol dissolution in a physiological solution, macropores were formed in CPC in the shapes of the original entrapped mannitol crystals, with diameters of 50 microm to 200 microm for cell infiltration and bone ingrowth. The resulting porosity in CPC ranged from 34.4% to 83.3% volume fraction. At 70.2% porosity, the hydroxyapatite scaffold possessed flexural strength (mean +/- sd; n = 6) of (2.5 +/- 0.2) MPa and elastic modulus of (0.71 +/- 0.10) GPa. These values were within the range for sintered porous hydroxyapatite and cancellous bone. Predictive equations were established by regression power-law fitting to the measured data (R(2) > 0.98) that described the relationships between scaffold porosity and strength, elastic modulus and fracture toughness. In conclusion, a new graft composition was developed that could be delivered during surgery in the form of a paste to harden in situ in the bone site to form macroporous hydroxyapatite. Compared to conventional CPC without macropores, the increased macroporosity of the new apatite scaffold may help facilitate implant fixation and

  13. Osteogenic cell response to 3-D hydroxyapatite scaffolds developed via replication of natural marine sponges.

    PubMed

    Clarke, S A; Choi, S Y; McKechnie, Melanie; Burke, G; Dunne, N; Walker, G; Cunningham, E; Buchanan, F

    2016-02-01

    Bone tissue engineering may provide an alternative to autograft, however scaffold optimisation is required to maximize bone ingrowth. In designing scaffolds, pore architecture is important and there is evidence that cells prefer a degree of non-uniformity. The aim of this study was to compare scaffolds derived from a natural porous marine sponge (Spongia agaricina) with unique architecture to those derived from a synthetic polyurethane foam. Hydroxyapatite scaffolds of 1 cm(3) were prepared via ceramic infiltration of a marine sponge and a polyurethane (PU) foam. Human foetal osteoblasts (hFOB) were seeded at 1 × 10(5) cells/scaffold for up to 14 days. Cytotoxicity, cell number, morphology and differentiation were investigated. PU-derived scaffolds had 84-91% porosity and 99.99% pore interconnectivity. In comparison marine sponge-derived scaffolds had 56-61% porosity and 99.9% pore interconnectivity. hFOB studies showed that a greater number of cells were found on marine sponge-derived scaffolds at than on the PU scaffold but there was no significant difference in cell differentiation. X-ray diffraction and inductively coupled plasma mass spectrometry showed that Si ions were released from the marine-derived scaffold. In summary, three dimensional porous constructs have been manufactured that support cell attachment, proliferation and differentiation but significantly more cells were seen on marine-derived scaffolds. This could be due both to the chemistry and pore architecture of the scaffolds with an additional biological stimulus from presence of Si ions. Further in vivo tests in orthotopic models are required but this marine-derived scaffold shows promise for applications in bone tissue engineering. PMID:26704539

  14. Fabrication of gelatin-strontium substituted calcium phosphate scaffolds with unidirectional pores for bone tissue engineering.

    PubMed

    Wu, Yu-Chun; Lin, Wei-Yu; Yang, Chyun-Yu; Lee, Tzer-Min

    2015-03-01

    This study fabricated homogeneous gelatin-strontium substituted calcium phosphate composites via coprecipitation in a gelatin solution. Unidirectional porous scaffolds with an oriented microtubular structure were then manufactured using freeze-drying technology. The resulting structure and pore alignment were determined using scanning electron microscopy. The pore size were in the range of 200-400 μm, which is considered ideal for the engineering of bone tissue. The scaffolds were further characterized using energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Hydroxyapatite was the main calcium phosphate compound in the scaffolds, with strontium incorporated into the crystal structure. The porosity of the scaffolds decreased with increasing concentration of calcium-phosphate. The compressive strength in the longitudinal direction was two to threefold higher than that observed in the transverse direction. Our results demonstrate that the composite scaffolds degraded by approximately 20 % after 5 weeks. Additionally, in vitro results reveal that the addition of strontium significantly increased human osteoblastic cells proliferation. Scaffolds containing strontium with a Sr-CaP/(gelatin + Sr-CaP) ratio of 50 % provided the most suitable environment for cell proliferation, particularly under dynamic culture conditions. This study demonstrates the considerable potential of composite scaffolds composed of gelatin-strontium-substituted calcium phosphate for applications in bone tissue engineering.

  15. Physical and degradation properties of PLGA scaffolds fabricated by salt fusion technique

    PubMed Central

    Mekala, Naveen Kumar; Baadhe, Rama Raju; Parcha, Sreenivasa Rao; Yalavarthy, Prameela Devi

    2013-01-01

    Tissue engineering scaffolds require a controlled pore size and interconnected pore structures to support the host tissue growth. In the present study, three dimensional (3D) hybrid scaffolds of poly lactic acid (PLA) and poly glycolic acid (PGA) were fabricated using solvent casting/particulate leaching. In this case, partially fused NaCl particles were used as porogen (200-300µ) to improve the overall porosity (≥90%) and internal texture of scaffolds. Differential scanning calorimeter (DSC) analysis of these porous scaffolds revealed a gradual reduction in glass transition temperature (Tg) (from 48°C to 42.5°C) with increase in hydrophilic PGA content. The potential applications of these scaffolds as implants were further tested for their biocompatibility and biodegradability in four simulated body fluid (SBF) types in vitro. Whereas, simulated body fluid (SBF) Type1 with the optimal amount of HCO3− ions was found to be more appropriate and sensible for testing the bioactivity of scaffolds. Among three combinations of polymer scaffolds, sample B with a ratio of 75:25 of PLA: PGA showed greater stability in body fluids (pH 7.2) with an optimum degradation rate (9% to 12% approx). X-ray diffractogram also confirmed a thin layer of hydroxyapatite deposition over sample B with all SBF types in vitro. PMID:23885272

  16. Fabrication of gelatin-strontium substituted calcium phosphate scaffolds with unidirectional pores for bone tissue engineering.

    PubMed

    Wu, Yu-Chun; Lin, Wei-Yu; Yang, Chyun-Yu; Lee, Tzer-Min

    2015-03-01

    This study fabricated homogeneous gelatin-strontium substituted calcium phosphate composites via coprecipitation in a gelatin solution. Unidirectional porous scaffolds with an oriented microtubular structure were then manufactured using freeze-drying technology. The resulting structure and pore alignment were determined using scanning electron microscopy. The pore size were in the range of 200-400 μm, which is considered ideal for the engineering of bone tissue. The scaffolds were further characterized using energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Hydroxyapatite was the main calcium phosphate compound in the scaffolds, with strontium incorporated into the crystal structure. The porosity of the scaffolds decreased with increasing concentration of calcium-phosphate. The compressive strength in the longitudinal direction was two to threefold higher than that observed in the transverse direction. Our results demonstrate that the composite scaffolds degraded by approximately 20 % after 5 weeks. Additionally, in vitro results reveal that the addition of strontium significantly increased human osteoblastic cells proliferation. Scaffolds containing strontium with a Sr-CaP/(gelatin + Sr-CaP) ratio of 50 % provided the most suitable environment for cell proliferation, particularly under dynamic culture conditions. This study demonstrates the considerable potential of composite scaffolds composed of gelatin-strontium-substituted calcium phosphate for applications in bone tissue engineering. PMID:25773230

  17. Physical and degradation properties of PLGA scaffolds fabricated by salt fusion technique.

    PubMed

    Mekala, Naveen Kumar; Baadhe, Rama Raju; Parcha, Sreenivasa Rao; Yalavarthy, Prameela Devi

    2013-07-01

    Tissue engineering scaffolds require a controlled pore size and interconnected pore structures to support the host tissue growth. In the present study, three dimensional (3D) hybrid scaffolds of poly lactic acid (PLA) and poly glycolic acid (PGA) were fabricated using solvent casting/particulate leaching. In this case, partially fused NaCl particles were used as porogen (200-300µ) to improve the overall porosity (≥90%) and internal texture of scaffolds. Differential scanning calorimeter (DSC) analysis of these porous scaffolds revealed a gradual reduction in glass transition temperature (Tg) (from 48°C to 42.5°C) with increase in hydrophilic PGA content. The potential applications of these scaffolds as implants were further tested for their biocompatibility and biodegradability in four simulated body fluid (SBF) types in vitro. Whereas, simulated body fluid (SBF) Type1 with the optimal amount of HCO3 (-) ions was found to be more appropriate and sensible for testing the bioactivity of scaffolds. Among three combinations of polymer scaffolds, sample B with a ratio of 75:25 of PLA: PGA showed greater stability in body fluids (pH 7.2) with an optimum degradation rate (9% to 12% approx). X-ray diffractogram also confirmed a thin layer of hydroxyapatite deposition over sample B with all SBF types in vitro. PMID:23885272

  18. Novel Scaffolds Fabricated Using Oleuropein for Bone Tissue Engineering

    PubMed Central

    Fan, Hui; Hui, Junfeng; Duan, Zhiguang; Fan, Daidi; Mi, Yu; Deng, Jianjun; Li, Hui

    2014-01-01

    We investigated the feasibility of oleuropein as a cross-linking agent for fabricating three-dimensional (3D) porous composite scaffolds for bone tissue engineering. Human-like collagen (HLC) and nanohydroxyapatite (n-HAp) were used to fabricate the composite scaffold by way of cross-linking. The mechanical tests revealed superior properties for the cross-linked scaffolds compared to the uncross-linked scaffolds. The as-obtained composite scaffold had a 3D porous structure with pores ranging from 120 to 300 μm and a porosity of 73.6 ± 2.3%. The cross-linked scaffolds were seeded with MC3T3-E1 Subclone 14 mouse osteoblasts. Fluorescence staining, the Cell Counting Kit-8 (CCK-8) assay, and scanning electron microscopy (SEM) indicated that the scaffolds enhanced cell adhesion and proliferation. Our results indicate the potential of these scaffolds for bone tissue engineering. PMID:24959582

  19. Assessment of protein entrapment in hydroxyapatite scaffolds by size exclusion chromatography.

    PubMed

    Espanol, Montserrat; Casals, Isidre; Lamtahri, Sarah; Valderas, Maria-Teresa; Ginebra, Maria-Pau

    2012-12-01

    Although it is well known that the textural properties of scaffolds play an important role in the process of tissue regeneration, the investigation of such effects remain difficult especially at the micro/nano level. Texture confers the material the additional ability to entrap/concentrate molecules circulating in the body fluid regardless of their binding affinity to the material. The goal of the present work is to isolate protein entrapment from protein adsorption phenomena in two macroporous hydroxyapatite scaffolds with identical chemical structure, similar macroporosity but different micro/nanoporosity using proteins of different sizes. This was achieved implementing size exclusion chromatography and using the scaffolds as chromatographic columns. The results showed that the larger the crystal size and the lower the packing density of the crystals composing the scaffold increased protein retention but decreased the protein dwelling time in the column. Differences in the amount of protein retained depended on the protein type.

  20. Preparation and characterization of nano-hydroxyapatite/silk fibroin porous scaffolds.

    PubMed

    Liu, Lin; Liu, Jinying; Wang, Mingqi; Min, Sijia; Cai, Yurong; Zhu, Liangjun; Yao, Juming

    2008-01-01

    Novel tissue engineering scaffold materials of nano-hydroxyapatite (nHA)/silk fibroin (SF) biocomposite were prepared by freeze-drying. The needle-like nHA crystals of about 10 nm in diameter by 50-80 nm in length, which were uniformly distributed in the porous nHA/SF scaffolds, were prepared by a co-precipitation method with a size. The as-prepared nHA/SF scaffolds showed good homogeneity, interconnected pores and high porosity. XRD and FT-IR analysis suggested that the silk fibroin was in beta-sheet structure, which usually provides outstanding mechanical properties for silk materials. In this work, composite scaffolds containing as high as 70% (w/w) nHA were prepared, which had excellent compressive modulus and strength, higher than the scaffolds at low nHA content level and other porous biodegradable polymeric scaffolds often considered in bone-related tissue engineering reported previously. The cell compatibility of composite scaffolds was evaluated through cell viability by MTT assay. All these results indicated that these nHA/SF scaffold materials may be a promising biomaterial for bone tissue engineering.

  1. Preparation and characterization of (PCL-crosslinked-PEG)/hydroxyapatite as bone tissue engineering scaffolds.

    PubMed

    Koupaei, Narjes; Karkhaneh, Akbar; Daliri Joupari, Morteza

    2015-12-01

    In this study, interconnected porous bioactive scaffolds were synthesized for bone tissue engineering. At the first step, poly( ɛ-caprolactone) (PCL) diols were diacrylated with acryloyl chloride. Then, the scaffolds were synthesized by radical crosslinking reaction of PCL and poly(ethyleneglycol) (PEG) diacrylates in the presence of hydroxyapatite (HA) particles. Morphological, swelling, thermal, and mechanical characteristics as well as degradability of the scaffolds were investigated. Results showed that increasing the ratio of PEG to PCL led to significant increase of swelling ratio and degradation rate, and decrease of crystallinity and compressive modulus of the networks, respectively. It was found that the incorporation of HA particles with the polymer matrices resulted in an augmented crystallinity, a decreased swelling ratio, and also a significantly increased compressive modulus of the networks. Cytocompatability and osteoconductivity of the scaffolds were assessed by MTT and alkaline phosphatase (ALP) assays, respectively. The results confirmed the cytocompatible nature of PCL/PEG/HA scaffolds with no toxicity. MG-63 cells attached and spread on the pore walls offered by the scaffolds. PCL/PEG/HA scaffolds compared with PCL/PEG ones showed higher ALP activity. Thus, the results indicated that the PCL/PEG/HA scaffolds have the potential of being used as promising substrates in bone tissue engineering.

  2. Silk-Hydroxyapatite Nanoscale Scaffolds with Programmable Growth Factor Delivery for Bone Repair.

    PubMed

    Ding, Zhaozhao; Fan, Zhihai; Huang, Xiaowei; Lu, Qiang; Xu, Weian; Kaplan, David L

    2016-09-21

    Osteoinductive biomaterials are attractive for repairing a variety of bone defects, and biomimetic strategies are useful toward developing bone scaffolds with such capacity. Here, a multiple biomimetic design was developed to improve the osteogenesis capacity of composite scaffolds consisting of hydroxyapatite nanoparticles (HA) and silk fibroin (SF). SF nanofibers and water-dispersible HA nanoparticles were blended to prepare the nanoscaled composite scaffolds with a uniform distribution of HA with a high HA content (40%), imitating the extracellular matrix (ECM) of bone. Bone morphogenetic protein-2 (BMP-2) was loaded in the SF scaffolds and HA to tune BMP-2 release. In vitro studies showed the preservation of BMP-2 bioactivity in the composite scaffolds, and programmable sustained release was achieved through adjusting the ratio of BMP-2 loaded on SF and HA. In vitro and in vivo osteogenesis studies demonstrated that the composite scaffolds showed improved osteogenesis capacity under suitable BMP-2 release conditions, significantly better than that of BMP-2 loaded SF-HA composite scaffolds reported previously. Therefore, these biomimetic SF-HA nanoscaled scaffolds with tunable BMP-2 delivery provide preferable microenvironments for bone regeneration. PMID:27579921

  3. 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.

  4. In Vitro Mineralization by Preosteoblasts in Poly(D, L-lactide-co-glycolide) Inverse Opal Scaffolds Reinforced with Hydroxyapatite Nanoparticles

    PubMed Central

    Choi, Sung-Wook; Zhang, Yu; Thomopoulos, Stavros; Xia, Younan

    2010-01-01

    Inverse opal scaffolds made of poly(D, L-lactide-co-glycolide) (PLGA) and hydroxyapatite (HAp) were fabricated using cubic-closed packed (ccp) lattices of uniform gelatin microspheres as templates and evaluated for bone tissue engineering. The scaffolds exhibited a uniform pore size (213 ± 4.4 μm), a porosity of ∼75%, and an excellent connectivity in three dimensions. Three different formulations were examined: pure PLGA, HAp-impregnated PLGA (PLGA/HAp), and apatite (Ap)-coated PLGA/HAp. After seeding with preosteoblasts (MC3T3-E1), the samples were cultured for different periods of time and then characterized by X-ray microcomputed tomography (micro-CT) and scanning electron microscopy to evaluate osteoinductivity in terms of the amount and spatial distribution of mineral secreted from the differentiated preosteoblasts. Our results indicate that preosteoblasts cultured in the Ap-coated PLGA/HAp scaffolds secreted the largest amount of mineral, which was also homogeneously distributed throughout the scaffolds. In contrast, the cells in the pure PLGA scaffolds secreted very little mineral, which was mainly deposited around the perimeter of the scaffolds. These results suggest that the uniform pore structure and favorable surface properties could facilitate the uniform secretion of extracellular matrix from cells throughout the scaffold. The Ap-coated PLGA/HAp scaffold with uniform pore structure could be a promising material for bone tissue engineering. PMID:20450216

  5. Coaxial electrospun aligned tussah silk fibroin nanostructured fiber scaffolds embedded with hydroxyapatite-tussah silk fibroin nanoparticles for bone tissue engineering.

    PubMed

    Shao, Weili; He, Jianxin; Sang, Feng; Ding, Bin; Chen, Li; Cui, Shizhong; Li, Kejing; Han, Qiming; Tan, Weilin

    2016-01-01

    The bone is a composite of inorganic and organic materials and possesses a complex hierarchical architecture consisting of mineralized fibrils formed by collagen molecules and coated with oriented hydroxyapatite. To regenerate bone tissue, it is necessary to provide a scaffold that mimics the architecture of the extracellular matrix in native bone. Here, we describe one such scaffold, a nanostructured composite with a core made of a composite of hydroxyapatite and tussah silk fibroin. The core is encased in a shell of tussah silk fibroin. The composite fibers were fabricated by coaxial electrospinning using green water solvent and were characterized using different techniques. In comparison to nanofibers of pure tussah silk, composite notably improved mechanical properties, with 90-fold and 2-fold higher initial modulus and breaking stress, respectively, obtained. Osteoblast-like MG-63 cells were cultivated on the composite to assess its suitability as a scaffold for bone tissue engineering. We found that the fiber scaffold supported cell adhesion and proliferation and functionally promoted alkaline phosphatase and mineral deposition relevant for biomineralization. In addition, the composite were more biocompatible than pure tussah silk fibroin or cover slip. Thus, the nanostructured composite has excellent biomimetic and mechanical properties and is a potential biocompatible scaffold for bone tissue engineering. PMID:26478319

  6. Coaxial electrospun aligned tussah silk fibroin nanostructured fiber scaffolds embedded with hydroxyapatite-tussah silk fibroin nanoparticles for bone tissue engineering.

    PubMed

    Shao, Weili; He, Jianxin; Sang, Feng; Ding, Bin; Chen, Li; Cui, Shizhong; Li, Kejing; Han, Qiming; Tan, Weilin

    2016-01-01

    The bone is a composite of inorganic and organic materials and possesses a complex hierarchical architecture consisting of mineralized fibrils formed by collagen molecules and coated with oriented hydroxyapatite. To regenerate bone tissue, it is necessary to provide a scaffold that mimics the architecture of the extracellular matrix in native bone. Here, we describe one such scaffold, a nanostructured composite with a core made of a composite of hydroxyapatite and tussah silk fibroin. The core is encased in a shell of tussah silk fibroin. The composite fibers were fabricated by coaxial electrospinning using green water solvent and were characterized using different techniques. In comparison to nanofibers of pure tussah silk, composite notably improved mechanical properties, with 90-fold and 2-fold higher initial modulus and breaking stress, respectively, obtained. Osteoblast-like MG-63 cells were cultivated on the composite to assess its suitability as a scaffold for bone tissue engineering. We found that the fiber scaffold supported cell adhesion and proliferation and functionally promoted alkaline phosphatase and mineral deposition relevant for biomineralization. In addition, the composite were more biocompatible than pure tussah silk fibroin or cover slip. Thus, the nanostructured composite has excellent biomimetic and mechanical properties and is a potential biocompatible scaffold for bone tissue engineering.

  7. [Study on the development of Ag-nano-hydroxyapatite/polyamide66 porous scaffolds with surface mineralization].

    PubMed

    Fan, Jianbo; Chang, Shan; Dong, Mina; Huang, Di; Li, Jidong; Jiang, Dianming

    2012-12-01

    Bacterial infection after implantation of bone tissue engineering scaffolds is still a serious clinical problem. Ag-nano-hydroxyapatite/polyamide66 (Ag-nHA/PA66) antibacterial composite scaffold were prepared with phase-inversion method in this study. The scaffolds were mineralized in saturated calcium phosphate solution at 37 degrees C for 1 day. The microstructure and the newly formed nano-apatite deposition on the scaffolds before and after mineralization were observed using scanning electron microscopy (SEM). In order to investigate the release behaviors of Ag+, the Ag-nHA/PA66 scaffolds were immersed into 5 ml PBS at 37 degrees C for a different period between 3 h and 168 h before and after mineralization. Then the samples were cultured with E. coli (8099) to test the antibacterial effect of the scaffolds. The results showed that, after mineralization, Ag-nHA/PA66 porous scaffolds still possessed a good inter-connection and a new apatite layer was formed on the surface of the scaffolds. The average macropore size was 626.61 +/- 141.94 microm, the porosity was 76.89 +/- 8.21% and the compressive strength was 2.94 +/- 1.12 MPa. All these physical parameters had no significant difference from those of the un-mineralized scaffolds. The Ag+ release of the scaffolds with and without mineralization was fast within 1 day and then kept slow and stable after 1 day. The antibacterial test confirmed that after mineralization the scaffolds had good antibacterial effects on E. coli. PMID:23469542

  8. Influence of Fe3O4 Nanoparticles in Hydroxyapatite Scaffolds on Proliferation of Primary Human Fibroblast Cells

    NASA Astrophysics Data System (ADS)

    Maleki-Ghaleh, H.; Aghaie, E.; Nadernezhad, A.; Zargarzadeh, M.; Khakzad, A.; Shakeri, M. S.; Beygi Khosrowshahi, Y.; Siadati, M. H.

    2016-06-01

    Modern techniques for expanding stem cells play a substantial role in tissue engineering: the raw material that facilitates regeneration of damaged tissues and treats diseases. The environmental conditions and bioprocessing methods are the primary determinants of the rate of cultured stem cell proliferation. Bioceramic scaffolds made of calcium phosphate are effective substrates for optimal cell proliferation. The present study investigates the effects of two bioceramic scaffolds on proliferating cells in culture media. One scaffold was made of hydroxyapatite and the other was a mixture of hydroxyapatite and ferromagnetic material (Fe3O4 nanoparticles). Disk-shaped (10 mm × 2 mm) samples of the two scaffolds were prepared. Primary human fibroblast proliferation was 1.8- and 2.5-fold faster, respectively, when cultured in the presence of hydroxyapatite or ferrous nanoparticle/hydroxyapatite mixtures. Optical microscopy images revealed that the increased proliferation was due to enhanced cell-cell contact. The presence of magnetic Fe3O4 nanoparticles in the ceramic scaffolds significantly increased cell proliferation compared to hydroxyapatite scaffolds and tissue culture polystyrene.

  9. Graphene oxide nanoflakes incorporated gelatin-hydroxyapatite scaffolds enhance osteogenic differentiation of human mesenchymal stem cells

    NASA Astrophysics Data System (ADS)

    Nair, Manitha; Nancy, D.; Krishnan, Amit G.; Anjusree, G. S.; Vadukumpully, Sajini; Nair, Shantikumar V.

    2015-04-01

    In this study, graphene oxide (GO) nanoflakes (0.5 and 1 wt%) were incorporated into a gelatin-hydroxyapatite (GHA) matrix through a freeze drying technique and its effect to enhance mechanical strength and osteogenic differentiation was studied. The GHA matrix with GO demonstrated less brittleness in comparison to GHA scaffolds. There was no significant difference in mechanical strength between GOGHA0.5 and GOGHA1.0 scaffolds. When the scaffolds were immersed in phosphate buffered saline (to mimic physiologic condition) for 60 days, around 50-60% of GO was released in sustained and linear manner and the concentration was within the toxicity limit as reported earlier. Further, GOGHA0.5 scaffolds were continued for cell culture experiments, wherein the scaffold induced osteogenic differentiation of human adipose derived mesenchymal stem cells without providing supplements like dexamethasone, L-ascorbic acid and β glycerophosphate in the medium. The level of osteogenic differentiation of stem cells was comparable to those cultured on GHA scaffolds with osteogenic supplements. Thus biocompatible, biodegradable and porous GO reinforced gelatin-HA 3D scaffolds may serve as a suitable candidate in promoting bone regeneration in orthopaedics.

  10. Indirect solid free form fabrication of local and global porous, biomimetic and composite 3D polymer-ceramic scaffolds.

    PubMed

    Taboas, J M; Maddox, R D; Krebsbach, P H; Hollister, S J

    2003-01-01

    Precise control over scaffold material, porosity, and internal pore architecture is essential for tissue engineering. By coupling solid free form (SFF) manufacturing with conventional sponge scaffold fabrication procedures, we have developed methods for casting scaffolds that contain designed and controlled locally porous and globally porous internal architectures. These methods are compatible with numerous bioresorbable and non-resorbable polymers, ceramics, and biologic materials. Phase separation, emulsion-solvent diffusion, and porogen leaching were used to create poly(L)lactide (PLA) scaffolds containing both computationally designed global pores (500, 600, or 800 microm wide channels) and solvent fashioned local pores (50-100 microm wide voids or 5-10 microm length plates). Globally porous PLA and polyglycolide/PLA discrete composites were made using melt processing. Biphasic scaffolds with mechanically interdigitated PLA and sintered hydroxyapatite regions were fabricated with 500 and 600 microm wide global pores. PLA scaffolds with complex internal architectures that mimicked human trabecular bone were produced. Our indirect fabrication using casting in SFF molds provided enhanced control over scaffold shape, material, porosity and pore architecture, including size, geometry, orientation, branching, and interconnectivity. These scaffolds that contain concurrent local and global pores, discrete material regions, and biomimetic internal architectures may prove valuable for multi-tissue and structural tissue interface engineering. PMID:12417192

  11. Electrospun biomimetic scaffold of hydroxyapatite/chitosan supports enhanced osteogenic differentiation of mMSCs

    NASA Astrophysics Data System (ADS)

    Peng, Hongju; Yin, Zi; Liu, Huanhuan; Chen, Xiao; Feng, Bei; Yuan, Huihua; Su, Bo; Ouyang, Hongwei; Zhang, Yanzhong

    2012-12-01

    Engaging functional biomaterial scaffolds to regulate stem cell differentiation has drawn a great deal of attention in the tissue engineering and regenerative medicine community. In this study, biomimetic composite nanofibrous scaffolds of hydroxyapatite/chitosan (HAp/CTS) were prepared to investigate their capacity for inducing murine mesenchymal stem cells (mMSCs) to differentiate into the osteogenic lineage, in the absence and presence of an osteogenic supplementation (i.e., ascorbic acid, β-glycerol phosphate, and dexamethasone), respectively. Using electrospun chitosan (CTS) nanofibrous scaffolds as the control, cell morphology, growth, specific osteogenic genes expression, and quantified proteins secretion on the HAp/CTS scaffolds were sequentially examined and assessed. It appeared that the HAp/CTS scaffolds supported better attachment and proliferation of the mMSCs. Most noteworthy was that in the absence of the osteogenic supplementation, expression of osteogenic genes including collagen I (Col I), runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and osteocalcin (OCN) were significantly upregulated in mMSCs cultured on the HAp/CTS nanofibrous scaffolds. Also increased secretion of the osteogenesis protein markers of alkaline phosphatase and collagen confirmed that the HAp/CTS nanofibrous scaffold markedly promoted the osteogenic commitment in the mMSCs. Moreover, the presence of osteogenic supplementation proved an enhanced efficacy of mMSC osteogenesis on the HAp/CTS nanofibrous scaffolds. Collectively, this study demonstrated that the biomimetic nanofibrous HAp/CTS scaffolds could support and enhance the adhesion, proliferation, and particularly osteogenic differentiation of the mMSCs. It also substantiated the potential of using biomimetic nanofibrous scaffolds of HAp/CTS for functional bone repair and regeneration applications.

  12. Collagen-Hydroxyapatite Scaffolds Induce Human Adipose Derived Stem Cells Osteogenic Differentiation In Vitro

    PubMed Central

    Fabbi, Claudia; Figallo, Elisa; Lo Furno, Debora; Gulino, Rosario; Colarossi, Cristina; Fullone, Francesco; Giuffrida, Rosario; Parenti, Rosalba; Memeo, Lorenzo; Forte, Stefano

    2016-01-01

    Mesenchymal stem cells (MSCs) play a crucial role in regulating normal skeletal homeostasis and, in case of injury, in bone healing and reestablishment of skeletal integrity. Recent scientific literature is focused on the development of bone regeneration models where MSCs are combined with biomimetic three-dimensional scaffolds able to direct MSC osteogenesis. In this work the osteogenic potential of human MSCs isolated from adipose tissue (hADSCs) has been evaluated in vitro in combination with collagen/Mg doped hydroxyapatite scaffolds. Results demonstrate the high osteogenic potential of hADSCs when cultured in specific differentiation induction medium, as revealed by the Alizarin Red S staining and gene expression profile analysis. In combination with collagen/hydroxyapatite scaffold, hADSCs differentiate into mature osteoblasts even in the absence of specific inducing factors; nevertheless, the supplement of the factors markedly accelerates the osteogenic process, as confirmed by the expression of specific markers of pre-osteoblast and mature osteoblast stages, such as osterix, osteopontin (also known as bone sialoprotein I), osteocalcin and specific markers of extracellular matrix maturation and mineralization stages, such as ALPL and osteonectin. Hence, the present work demonstrates that the scaffold per se is able to induce hADSCs differentiation, while the addition of osteo-inductive factors produces a significant acceleration of the osteogenic process. This observation makes the use of our model potentially interesting in the field of regenerative medicine for the treatment of bone defects. PMID:26982592

  13. Development of a new carbon nanotube–alginate–hydroxyapatite tricomponent composite scaffold for application in bone tissue engineering

    PubMed Central

    Rajesh, Rajendiran; Dominic Ravichandran, Y

    2015-01-01

    In recent times, tricomponent scaffolds prepared from naturally occurring polysaccharides, hydroxyapatite, and reinforcing materials have been gaining increased attention in the field of bone tissue engineering. In the current work, a tricomponent scaffold with an oxidized multiwalled carbon nanotube (fMWCNT)–alginate–hydroxyapatite with the required porosity was prepared for the first time by a freeze-drying method and characterized using analytical techniques. The hydroxyapatite for the scaffold was isolated from chicken bones by thermal calcination at 800°C. The Fourier transform infrared spectra and X-ray diffraction data confirmed ionic interactions and formation of the fMWCNT–alginate–hydroxyapatite scaffold. Interconnected porosity with a pore size of 130–170 µm was evident from field emission scanning electron microscopy. The total porosity calculated using the liquid displacement method was found to be 93.85%. In vitro biocompatibility and cell proliferation on the scaffold was checked using an MG-63 cell line by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cell attachment by Hoechst stain assay. In vitro studies showed better cell proliferation, cell differentiation, and cell attachment on the prepared scaffold. These results indicate that this scaffold could be a promising candidate for bone tissue engineering. PMID:26491303

  14. Towards the synthesis of hydroxyapatite/protein scaffolds with controlled porosities: bulk and interfacial shear rheology of a hydroxyapatite suspension with protein additives.

    PubMed

    Maas, Michael; Bodnar, Pedro Marcus; Hess, Ulrike; Treccani, Laura; Rezwan, Kurosch

    2013-10-01

    The synthesis of porous hydroxyapatite scaffolds is essential for biomedical applications such as bone tissue engineering and replacement. One way to induce macroporosity, which is needed to support bone in-growth, is to use protein additives as foaming agents. Another reason to use protein additives is the potential to introduce a specific biofunctionality to the synthesized scaffolds. In this work, we study the rheological properties of a hydroxyapatite suspension system with additions of the proteins bovine serum albumin (BSA), lysozyme (LSZ) and fibrinogen (FIB). Both the rheology of the bulk phase as well as the interfacial shear rheology are studied. The bulk rheological data provides important information on the setting behavior of the thixotropic suspension, which we find to be faster with the addition of FIB and LSZ and much slower with BSA. Foam bubble stabilization mechanisms can be rationalized via interfacial shear rheology and we show that it depends on the growth of interfacial films at the suspension/air interface. These interfacial films support the stabilization of bubbles within the ceramic matrix and thereby introduce macropores. Due to the weak interaction of the protein molecules with the hydroxyapatite particles of the suspension, we find that BSA forms the most stable interfacial films, followed by FIB. LSZ strongly interacts with the hydroxyapatite particles and thus only forms thin films with very low elastic moduli. In summary, our study provides fundamental rheological insights which are essential for tailoring hydroxyapatite/protein suspensions in order to synthesize scaffolds with controlled porosities.

  15. Poly(l-Lactic Acid)/Gelatin Fibrous Scaffold Loaded with Simvastatin/Beta-Cyclodextrin-Modified Hydroxyapatite Inclusion Complex for Bone Tissue Regeneration.

    PubMed

    Lee, Jung Bok; Kim, Ji Eun; Balikov, Daniel A; Bae, Min Soo; Heo, Dong Nyoung; Lee, Donghyun; Rim, Hyun Joon; Lee, Deok-Won; Sung, Hak-Joon; Kwon, Il Keun

    2016-07-01

    Recently, the application of nanostructured materials in the field of tissue engineering has garnered attention to mediate treatment and regeneration of bone defects. In this study, poly(l-lactic acid) (PLLA)/gelatin (PG) fibrous scaffolds are fabricated and β-cyclodextrin (βCD) grafted nano-hydroxyapatite (HAp) is coated onto the fibrous scaffold surface via an interaction between βCD and adamantane. Simvastatin (SIM), which is known to promote osteoblast viability and differentiation, is loaded into the remaining βCD. The specimen morphologies are characterized by scanning electron microscopy. The release profile of SIM from the drug loaded scaffold is also evaluated. In vitro proliferation and osteogenic differentiation of human adipose derived stem cells on SIM/HAp coated PG composite scaffolds is characterized by alkaline phosphatase (ALP) activity, mineralization (Alizarin Red S staining), and real time Polymerase chain reaction (PCR). The scaffolds are then implanted into rabbit calvarial defects and analyzed by microcomputed tomography for bone formation after four and eight weeks. These results demonstrate that SIM loaded PLLA/gelatin/HAp-(βCD) scaffolds promote significantly higher ALP activity, mineralization, osteogenic gene expression, and bone regeneration than control scaffolds. This suggests the potential application of this material toward bone tissue engineering. PMID:26996294

  16. Poly(l-Lactic Acid)/Gelatin Fibrous Scaffold Loaded with Simvastatin/Beta-Cyclodextrin-Modified Hydroxyapatite Inclusion Complex for Bone Tissue Regeneration.

    PubMed

    Lee, Jung Bok; Kim, Ji Eun; Balikov, Daniel A; Bae, Min Soo; Heo, Dong Nyoung; Lee, Donghyun; Rim, Hyun Joon; Lee, Deok-Won; Sung, Hak-Joon; Kwon, Il Keun

    2016-07-01

    Recently, the application of nanostructured materials in the field of tissue engineering has garnered attention to mediate treatment and regeneration of bone defects. In this study, poly(l-lactic acid) (PLLA)/gelatin (PG) fibrous scaffolds are fabricated and β-cyclodextrin (βCD) grafted nano-hydroxyapatite (HAp) is coated onto the fibrous scaffold surface via an interaction between βCD and adamantane. Simvastatin (SIM), which is known to promote osteoblast viability and differentiation, is loaded into the remaining βCD. The specimen morphologies are characterized by scanning electron microscopy. The release profile of SIM from the drug loaded scaffold is also evaluated. In vitro proliferation and osteogenic differentiation of human adipose derived stem cells on SIM/HAp coated PG composite scaffolds is characterized by alkaline phosphatase (ALP) activity, mineralization (Alizarin Red S staining), and real time Polymerase chain reaction (PCR). The scaffolds are then implanted into rabbit calvarial defects and analyzed by microcomputed tomography for bone formation after four and eight weeks. These results demonstrate that SIM loaded PLLA/gelatin/HAp-(βCD) scaffolds promote significantly higher ALP activity, mineralization, osteogenic gene expression, and bone regeneration than control scaffolds. This suggests the potential application of this material toward bone tissue engineering.

  17. 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.

  18. Hydroxyapatite-doped alginate beads as scaffolds for the osteoblastic differentiation of mesenchymal stem cells.

    PubMed

    Wang, Martha O; Bracaglia, Laura; Thompson, Joshua A; Fisher, John P

    2016-09-01

    This work investigates the role of an osteoblastic matrix component, hydroxyapatite (HA), in modular alginate scaffolds to support osteoblastic differentiation of human mesenchymal stem cells for the purpose of tissue engineered bone constructs. This system is first evaluated in a tubular perfusion bioreactor, which has been shown to improve osteoblastic differentiation over static culture conditions. HMSCs in alginate scaffolds that contain HA show increased osteoblastic gene expression compared to cells in pure alginate scaffolds, as well as significantly more matrix production and mineralization. The differentiated hMSCs and cell-laid matrix are ultimately evaluated in an in vivo site specific model. Implantation of these scaffolds with preformed matrix into the rat femoral condyle defects results in abundant bone growth and significant incorporation of the scaffold into the surrounding tissue. The developed mineralized matrix, induced in part by the HA component in the scaffold, could lead to increased tissue development in critically sized defects, and should be included in future implant strategies. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2325-2333, 2016.

  19. Improving osteointegration and osteogenesis of three-dimensional porous Ti6Al4V scaffolds by polydopamine-assisted biomimetic hydroxyapatite coating.

    PubMed

    Li, Yong; Yang, Wei; Li, Xiaokang; Zhang, Xing; Wang, Cairu; Meng, Xiangfei; Pei, Yifeng; Fan, Xiangli; Lan, Pingheng; Wang, Chunhui; Li, Xiaojie; Guo, Zheng

    2015-03-18

    Titanium alloys with various porous structures can be fabricated by advanced additive manufacturing techniques, which are attractive for use as scaffolds for bone defect repair. However, modification of the scaffold surfaces, particularly inner surfaces, is critical to improve the osteointegration of these scaffolds. In this study, a biomimetic approach was employed to construct polydopamine-assisted hydroxyapatite coating (HA/pDA) onto porous Ti6Al4V scaffolds fabricated by the electron beam melting method. The surface modification was characterized with the field emission scanning electron microscopy, energy dispersive spectroscopy, water contact angle measurement, and confocal laser scanning microscopy. Attachment and proliferation of MC3T3-E1 cells on the scaffold surface were significantly enhanced by the HA/pDA coating compared to the unmodified surfaces. Additionally, MC3T3-E1 cells grown on the HA/pDA-coated Ti6Al4V scaffolds displayed significantly higher expression of runt-related transcription factor-2, alkaline phosphatase, osteocalcin, osteopontin, and collagen type-1 compared with bare Ti6Al4V scaffolds after culture for 14 days. Moreover, microcomputed tomography analysis and Van-Gieson staining of histological sections showed that HA/pDA coating on surfaces of porous Ti6Al4V scaffolds enhanced osteointegration and significantly promoted bone regeneration after implantation in rabbit femoral condylar defects for 4 and 12 weeks. Therefore, this study provides an alternative to biofunctionalized porous Ti6Al4V scaffolds with improved osteointegration and osteogenesis functions for orthopedic applications.

  20. Improving osteointegration and osteogenesis of three-dimensional porous Ti6Al4V scaffolds by polydopamine-assisted biomimetic hydroxyapatite coating.

    PubMed

    Li, Yong; Yang, Wei; Li, Xiaokang; Zhang, Xing; Wang, Cairu; Meng, Xiangfei; Pei, Yifeng; Fan, Xiangli; Lan, Pingheng; Wang, Chunhui; Li, Xiaojie; Guo, Zheng

    2015-03-18

    Titanium alloys with various porous structures can be fabricated by advanced additive manufacturing techniques, which are attractive for use as scaffolds for bone defect repair. However, modification of the scaffold surfaces, particularly inner surfaces, is critical to improve the osteointegration of these scaffolds. In this study, a biomimetic approach was employed to construct polydopamine-assisted hydroxyapatite coating (HA/pDA) onto porous Ti6Al4V scaffolds fabricated by the electron beam melting method. The surface modification was characterized with the field emission scanning electron microscopy, energy dispersive spectroscopy, water contact angle measurement, and confocal laser scanning microscopy. Attachment and proliferation of MC3T3-E1 cells on the scaffold surface were significantly enhanced by the HA/pDA coating compared to the unmodified surfaces. Additionally, MC3T3-E1 cells grown on the HA/pDA-coated Ti6Al4V scaffolds displayed significantly higher expression of runt-related transcription factor-2, alkaline phosphatase, osteocalcin, osteopontin, and collagen type-1 compared with bare Ti6Al4V scaffolds after culture for 14 days. Moreover, microcomputed tomography analysis and Van-Gieson staining of histological sections showed that HA/pDA coating on surfaces of porous Ti6Al4V scaffolds enhanced osteointegration and significantly promoted bone regeneration after implantation in rabbit femoral condylar defects for 4 and 12 weeks. Therefore, this study provides an alternative to biofunctionalized porous Ti6Al4V scaffolds with improved osteointegration and osteogenesis functions for orthopedic applications. PMID:25711714

  1. A novel one-pot process for near-net-shape fabrication of open-porous resorbable hydroxyapatite/protein composites and in vivo assessment.

    PubMed

    Mueller, Berit; Koch, Dietmar; Lutz, Rainer; Schlegel, Karl A; Treccani, Laura; Rezwan, Kurosch

    2014-09-01

    We present a mild one-pot freeze gelation process for fabricating near-net, complex-shaped hydroxyapatite scaffolds and to directly incorporate active proteins during scaffold processing. In particular, the direct protein incorporation enables a simultaneous adjustment and control of scaffold microstructure, porosity, resorbability and enhancement of initial mechanical and handling stability. Two proteins, serum albumin and lysozyme, are selected and their effect on scaffold stability and microstructure investigated by biaxial strength tests, electron microscopy, and mercury intrusion porosimetry. The resulting hydroxyapatite/protein composites feature adjustable porosities from 50% to 70% and a mechanical strength ranging from 2 to 6 MPa comparable to that of human spongiosa without any sintering step. Scaffold degradation behaviour and protein release are assessed by in vitro studies. A preliminary in vivo assessment of scaffold biocompatibility and resorption behaviour in adult domestic pigs is discussed. After implantation, composites were resorbed up to 50% after only 4 weeks and up to 65% after 8 weeks. In addition, 14% new bone formation after 4 weeks and 37% after 8 weeks were detected. All these investigations demonstrate the outstanding suitability of the one-pot-process to create, in a customisable and reliable way, biocompatible scaffolds with sufficient mechanical strength for handling and surgical insertion, and for potential use as biodegradable bone substitutes and versatile platform for local drug delivery.

  2. A novel one-pot process for near-net-shape fabrication of open-porous resorbable hydroxyapatite/protein composites and in vivo assessment.

    PubMed

    Mueller, Berit; Koch, Dietmar; Lutz, Rainer; Schlegel, Karl A; Treccani, Laura; Rezwan, Kurosch

    2014-09-01

    We present a mild one-pot freeze gelation process for fabricating near-net, complex-shaped hydroxyapatite scaffolds and to directly incorporate active proteins during scaffold processing. In particular, the direct protein incorporation enables a simultaneous adjustment and control of scaffold microstructure, porosity, resorbability and enhancement of initial mechanical and handling stability. Two proteins, serum albumin and lysozyme, are selected and their effect on scaffold stability and microstructure investigated by biaxial strength tests, electron microscopy, and mercury intrusion porosimetry. The resulting hydroxyapatite/protein composites feature adjustable porosities from 50% to 70% and a mechanical strength ranging from 2 to 6 MPa comparable to that of human spongiosa without any sintering step. Scaffold degradation behaviour and protein release are assessed by in vitro studies. A preliminary in vivo assessment of scaffold biocompatibility and resorption behaviour in adult domestic pigs is discussed. After implantation, composites were resorbed up to 50% after only 4 weeks and up to 65% after 8 weeks. In addition, 14% new bone formation after 4 weeks and 37% after 8 weeks were detected. All these investigations demonstrate the outstanding suitability of the one-pot-process to create, in a customisable and reliable way, biocompatible scaffolds with sufficient mechanical strength for handling and surgical insertion, and for potential use as biodegradable bone substitutes and versatile platform for local drug delivery. PMID:25063103

  3. Nano-scaled hydroxyapatite/polymer composite IV. Fabrication and cell adhesion properties of a three-dimensional scaffold made of composite material with a silk fibroin substrate to develop a percutaneous device.

    PubMed

    Furuzono, Tsutomu; Yasuda, Shoji; Kimura, Tsuyoshi; Kyotani, Singo; Tanaka, Junzo; Kishida, Akio

    2004-01-01

    Nano-scaled sintered hydroxyapatite (HAp) particles with an a-axis length of 87 +/- 23 nm, a c-axis length of 236 +/- 81 nm, and a mean aspect ratio ( c/ a) of 2.72 were covalently linked onto a silk fibroin (SF) substrate chemically modified by graft polymerization with gamma-methacryloxypropyl trimethoxysilane (MPTS). Graft polymerization with poly(MPTS) on SF was conducted by free-radical initiation in a water solvent with pentaethylene glycol dodecyl ether as a nonionic surfactant. The alkoxysilyl groups of the graft polymers avoided hydrolysis and maintained their activity in coupling with the hydroxyl groups on the HAp surface despite the use of water as the reaction solvent. The weight gain of poly(MPTS) on SF increased with increasing the reaction time, eventually reaching a plateau value of about 15 wt% after 50 min of reaction time. After HAp covalent coating, the particles separated or aggregated into several crystals, as shown by scanning electron microscopic observation. L929 fibroblast cells adhered more plentifully on HAp-coated SF compared to untreated SF and hydrolyzed poly(MPTS)-grafted SF during 24 h or 48 h of incubation. The cells adhered only on the HAp surface but not at all on the dehydrated grafted surface of SF without HAp. A button-shaped prototype for a percutaneous device was manufactured by transplantation of HAp-coated SF fibers of about 100 microm in length onto silicone moldings using an adhesive, and the device showed good cell adhesiveness.

  4. Biocomposite scaffolds for bone regeneration: Role of chitosan and hydroxyapatite within poly-3-hydroxybutyrate-co-3-hydroxyvalerate on mechanical properties and in vitro evaluation.

    PubMed

    Zhang, Sai; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

    2015-11-01

    Bio-engineered scaffolds for bone tissue regeneration is an exploding area of research mainly because they can satisfy the essential demands and current challenges in bone replacement therapies, by imitating the extracellular matrix (ECM) of the native bone. We fabricated bio-composite nanofibrous scaffolds with a blend of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV), chitosan (CTS) and hydroxyapatite (HA) during this study. Morphological evaluation confirmed the fiber diameters of PHBV, PHBV/CTS (90:10), PHBV/CTS/HA4 (85.5:9.5:5) and PHBV/CTS/HA8 (81:9:10) as 405 ± 74 nm, 334 ± 82 nm, 316 ± 103 nm and 256 ± 110 nm, respectively. The PHBV/CTS/HA4 and PHBV/CTS/HA8 scaffolds were capable of enduring the long term culture of human fetal osteoblasts (hFOB) with ultimate tensile strength of 3.55 ± 0.22 MPa and 4.19 ± 0.19 MPa, respectively. The proliferation of osteoblasts on PHBV/CTS/HA8 scaffold was found 34.10% higher than that on PHBV scaffold on day 20. Cell maturation identified by alkaline phosphatase activity on day 20 was significantly higher on PHBV/CTS/HA8 scaffold than that on PHBV scaffold. The cells on PHBV/CTS/HA8 scaffold also acquired higher mineral deposition (25.79%) than the mineral deposition on PHBV scaffold by day 20, confirmed by EDX analysis. Based on the results, we concluded that the electrospun PHBV/CTS/HA8 scaffolds hold great potential to promote the regeneration of bone tissue due to the synergistic effect of chitosan and HA, whereby chitosan provided cell recognition sites while HA acted as a chelating agent for organizing the apatite-like mineralization. PMID:26232670

  5. Three-dimensional polycaprolactone-hydroxyapatite scaffolds combined with bone marrow cells for cartilage tissue engineering.

    PubMed

    Wei, Bo; Yao, Qingqiang; Guo, Yang; Mao, Fengyong; Liu, Shuai; Xu, Yan; Wang, Liming

    2015-08-01

    The goal of this study was to investigate the chondrogenic potential of three-dimensional polycaprolactone-hydroxyapatite (PCL-HA) scaffolds loaded with bone marrow cells in vitro and the effect of PCL-HA scaffolds on osteochondral repair in vivo. Here, bone marrow was added to the prepared PCL-HA scaffolds and cultured in chondrogenic medium for 10 weeks. Osteochondral defects were created in the trochlear groove of 29 knees in 17 New Zealand white rabbits, which were then divided into four groups that underwent: implantation of PCL-HA scaffolds (left knee, n = 17; Group 1), microfracture (right knee, n = 6; Group 2), autologous osteochondral transplantation (right knee, n = 6; Group 3), and no treatment (right knee, n = 5; Control). Extracellular matrix produced by bone marrow cells covered the surface and filled the pores of PCL-HA scaffolds after 10 weeks in culture. Moreover, many cell-laden cartilage lacunae were observed, and cartilage matrix was concentrated in the PCL-HA scaffolds. After a 12-week repair period, Group 1 showed excellent vertical and lateral integration with host bone, but incomplete cartilage regeneration and matrix accumulation. An uneven surface of regenerated cartilage and reduced distribution of cartilage matrix were observed in Group 2. In addition, abnormal bone growth and unstable integration between repaired and host tissues were detected. For Group 3, the integration between transplanted and host cartilage was interrupted. Our findings indicate that the PCL-HA scaffolds loaded with bone marrow cells improved chondrogenesis in vitro and implantation of PCL-HA scaffolds for osteochondral repairenhanced integration with host bone. However, cartilage regeneration remained unsatisfactory. The addition of trophic factors or the use of precultured cell-PCL-HA constructs for accelerated osteochondral repair requires further investigation.

  6. Electrospun fibrous scaffolds combined with nanoscale hydroxyapatite induce osteogenic differentiation of human periodontal ligament cells

    PubMed Central

    Wu, Xiaonan; Miao, Leiying; Yao, Yingfang; Wu, Wenlei; Liu, Yu; Chen, Xiaofeng; Sun, Weibin

    2014-01-01

    Periodontal repair is a complex process in which regeneration of alveolar bone is a vital component. The aim of this study was to develop a biodegradable scaffold with good biocompatibility and osteoinductive ability. Two types of composite fibrous scaffolds were produced by electrospinning, ie, type I collagen/poly(ε-caprolactone) (COL/PCL) and type I collagen/poly(ε-caprolactone)/nanoscale hydroxyapatite (COL/PCL/nHA) with an average fiber diameter of about 377 nm. After a simulated body fluid (SBF) immersion test, the COL/PCL/nHA-SBF scaffold developed a rough surface because of the calcium phosphate deposited on the fibers, suggesting that the presence of nHA promoted the mineralization potential of the scaffold. Energy dispersive X-ray spectroscopy clearly showed the calcium and phosphorus content in the COL/PCL/nHA and COL/PCL/nHA-SBF scaffolds, confirming the findings of nHA and calcium phosphate precipitation on scanning electron micrographs. Water contact analysis revealed that nHA could improve the hydrophilic nature of the COL/PCL/nHA-SBF scaffold. The morphology of periodontal ligament cells cultured on COL/PCL-SBF and COL/PCL/nHA-SBF was evaluated by scanning electron microscopy. The results showed that cells adhered to either type of scaffold and were slightly spindle-shaped in the beginning, then extended gradually with stretched filopodia, indicating an ability to fill the fiber pores. A Cell Counting Kit-8 assay showed that both scaffolds supported cell proliferation. However, real-time quantitative polymerase chain reaction analysis showed that expression of the bone-related markers, alkaline phosphatase and osteocalcin, was upregulated only on the COL/PCL/nHA-SBF scaffold, indicating that this scaffold had the ability to induce osteogenic differentiation of periodontal ligament cells. In this study, COL/PCL/nHA-SBF produced by electrospinning followed by biomimetic mineralization had combined electrospun fibers with nHA in it. This scaffold has

  7. Electrospun fibrous scaffolds combined with nanoscale hydroxyapatite induce osteogenic differentiation of human periodontal ligament cells.

    PubMed

    Wu, Xiaonan; Miao, Leiying; Yao, Yingfang; Wu, Wenlei; Liu, Yu; Chen, Xiaofeng; Sun, Weibin

    2014-01-01

    Periodontal repair is a complex process in which regeneration of alveolar bone is a vital component. The aim of this study was to develop a biodegradable scaffold with good biocompatibility and osteoinductive ability. Two types of composite fibrous scaffolds were produced by electrospinning, ie, type I collagen/poly(ε-caprolactone) (COL/PCL) and type I collagen/poly(ε-caprolactone)/nanoscale hydroxyapatite (COL/PCL/nHA) with an average fiber diameter of about 377 nm. After a simulated body fluid (SBF) immersion test, the COL/PCL/nHA-SBF scaffold developed a rough surface because of the calcium phosphate deposited on the fibers, suggesting that the presence of nHA promoted the mineralization potential of the scaffold. Energy dispersive X-ray spectroscopy clearly showed the calcium and phosphorus content in the COL/PCL/nHA and COL/PCL/nHA-SBF scaffolds, confirming the findings of nHA and calcium phosphate precipitation on scanning electron micrographs. Water contact analysis revealed that nHA could improve the hydrophilic nature of the COL/PCL/nHA-SBF scaffold. The morphology of periodontal ligament cells cultured on COL/PCL-SBF and COL/PCL/nHA-SBF was evaluated by scanning electron microscopy. The results showed that cells adhered to either type of scaffold and were slightly spindle-shaped in the beginning, then extended gradually with stretched filopodia, indicating an ability to fill the fiber pores. A Cell Counting Kit-8 assay showed that both scaffolds supported cell proliferation. However, real-time quantitative polymerase chain reaction analysis showed that expression of the bone-related markers, alkaline phosphatase and osteocalcin, was upregulated only on the COL/PCL/nHA-SBF scaffold, indicating that this scaffold had the ability to induce osteogenic differentiation of periodontal ligament cells. In this study, COL/PCL/nHA-SBF produced by electrospinning followed by biomimetic mineralization had combined electrospun fibers with nHA in it. This scaffold has

  8. Osteogenic effect of controlled released rhBMP-2 in 3D printed porous hydroxyapatite scaffold.

    PubMed

    Wang, Hai; Wu, Gui; Zhang, Jing; Zhou, Kui; Yin, Bo; Su, Xinlin; Qiu, Guixing; Yang, Guang; Zhang, Xianglin; Zhou, Gang; Wu, Zhihong

    2016-05-01

    Recently, 3D printing as effective technology has been highlighted in the biomedical field. Previously, a porous hydroxyapatite (HA) scaffold with the biocompatibility and osteoconductivity has been developed by this method. However, its osteoinductivity is limited. The main purpose of this study was to improve it by the introduction of recombinant human bone morphogenetic protein-2 (rhBMP-2). This scaffold was developed by coating rhBMP-2-delivery microspheres with collagen. These synthesized scaffolds were characterized by Scanning Electron Microscopy (SEM), a delivery test in vitro, cell culture, and the experiments in vivo by a Micro-computed tomography (μCT) scan and histological evaluation of VanGieson staining. SEM results indicated the surface of scaffolds were more fit for the adhesion of hMSCs to coat collagen/rhBMP-2 microspheres. Biphasic release of rhBMP-2 could continue for more than 21 days, and keep its osteoinductivity to induce osteogenic differentiation of hMSCs in vitro. In addition, the experiments in vivo showed that the scaffold had a good bone regeneration capacity. These findings demonstrate that the HA/Collagen/Chitosan Microspheres system can simultaneously achieve localized long-term controlled release of rhBMP-2 and bone regeneration, which provides a promising route for improving the treatment of bone defects.

  9. Incorporation of polymeric microparticles into collagen-hydroxyapatite scaffolds for the delivery of a pro-osteogenic peptide for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    López-Noriega, Adolfo; Quinlan, Elaine; Celikkin, Nehar; O'Brien, Fergal J.

    2015-01-01

    Collagen-hydroxyapatite scaffolds are outstanding materials for bone tissue engineering as they are biocompatible, bioresorbable, osteoconductive, and osteoinductive. The objective of the present work was to assess the potential of increasing their regenerative capacity by functionalising the scaffolds for therapeutic delivery. This was achieved by the utilization of polymeric drug carriers. With this purpose, alginate, chitosan, gelatine, and poly(lactic-co-glycolic acid) (PLGA) microparticles eluting PTHrP 107-111, an osteogenic pentapeptide, were fabricated and tested by incorporating them into the scaffolds. Among them, PLGA microparticles show the most promising characteristics for use as drug delivery devices. Following the incorporation of the microparticles, the scaffolds maintained their interconnected porous structure and the mechanical properties of the materials were not adversely affected. In addition, the microparticles released all their PTHrP 107-111 cargo. Most importantly, the delivered peptide proved to be bioactive and promoted enhanced osteogenesis as assessed by alkaline phosphatase production and osteocalcin and osteopontin gene expression when pre-osteoblastic cells were seeded on the scaffolds. While the focus was on bone repair, the release system described in this study can be used for the delivery of therapeutics for healing and regeneration of a variety of tissue types depending on the type of collagen scaffold chosen.

  10. Gold and Hydroxyapatite Nano-Composite Scaffolds for Anterior Cruciate Ligament Reconstruction: In Vitro Characterization.

    PubMed

    Smith, S E; White, R A; Grant, D A; Grant, S A

    2016-01-01

    Current anterior cruciate ligament (ACL) graft replacement materials often fail due to the lack of biological integration. While many newly developed extracellular matrix based scaffolds show good biocompatibility they often do not entice cellular remodeling and the rebuilding of a functional ligament. We have proposed the conjugation of gold nanoparticles (AuNP) and hydroxyapatite nanoparticles (nano-HAp) to acellular tissue to enhance cell attachment and proliferation while maintaining an improved degradation resistance and open microstructure. We are the first to investigate the double conjugation of AuNP and nano-HAp onto decellularized tissue to improve the tissue remodeling response. Decellularized porcine diaphragm was crosslinked with two types of nano-HAp and amine-functionalized AuNP with 1-ethyl-3-(3-dimethlaminopropyl) carbodiimide (EDC) crosslinker. Scaffolds were characterized using electron microscopy, differential scanning calorimetry, and fibroblast assays. Results demonstrated that scaffolds with nano-HAp have increased thermal stability at low levels of crosslinking. The open microstructure of the scaffold was not compromised allowing for cell migration while still providing increased degradation resistance. The addition of < 200 nm nano-HAp decreased cell viability compared to scaffolds without nanoparticles, but the addition of AuNP to scaffolds showed enhanced cell viability in the presence of < 200 nm nano-HAp. The addition of < 40 nm nano-HAp showed an increase in cell viability compared to scaffolds crosslinked without nanoparticles. It is concluded that attaching AuNP and < 40nm nano-HAp to extracellular matrices may improve overall properties. PMID:27398580

  11. Gold and Hydroxyapatite Nano-Composite Scaffolds for Anterior Cruciate Ligament Reconstruction: In Vitro Characterization.

    PubMed

    Smith, S E; White, R A; Grant, D A; Grant, S A

    2016-01-01

    Current anterior cruciate ligament (ACL) graft replacement materials often fail due to the lack of biological integration. While many newly developed extracellular matrix based scaffolds show good biocompatibility they often do not entice cellular remodeling and the rebuilding of a functional ligament. We have proposed the conjugation of gold nanoparticles (AuNP) and hydroxyapatite nanoparticles (nano-HAp) to acellular tissue to enhance cell attachment and proliferation while maintaining an improved degradation resistance and open microstructure. We are the first to investigate the double conjugation of AuNP and nano-HAp onto decellularized tissue to improve the tissue remodeling response. Decellularized porcine diaphragm was crosslinked with two types of nano-HAp and amine-functionalized AuNP with 1-ethyl-3-(3-dimethlaminopropyl) carbodiimide (EDC) crosslinker. Scaffolds were characterized using electron microscopy, differential scanning calorimetry, and fibroblast assays. Results demonstrated that scaffolds with nano-HAp have increased thermal stability at low levels of crosslinking. The open microstructure of the scaffold was not compromised allowing for cell migration while still providing increased degradation resistance. The addition of < 200 nm nano-HAp decreased cell viability compared to scaffolds without nanoparticles, but the addition of AuNP to scaffolds showed enhanced cell viability in the presence of < 200 nm nano-HAp. The addition of < 40 nm nano-HAp showed an increase in cell viability compared to scaffolds crosslinked without nanoparticles. It is concluded that attaching AuNP and < 40nm nano-HAp to extracellular matrices may improve overall properties.

  12. Nonwoven silk fibroin net/nano-hydroxyapatite scaffold: preparation and characterization.

    PubMed

    Zhao, Yong; Chen, Jing; Chou, Alex H K; Li, Gang; LeGeros, Racquel Z

    2009-12-15

    The purpose of this study was to prepare and characterize a three-dimensional scaffold consisting of porous nonwoven silk fibroin net/nano-apatite composite. The silk fibroin net was mineralized with apatite by alternative soaking in calcium and phosphate solutions. The scaffold exhibited a porous microstructure with open porosity (70-78%), with an average pore size of about 163 +/- 40.0 microm. The swelling ratio and water uptake were 4.55% and 81.93%, respectively, indicating excellent hydrophilicity. The nano-sized hydroxyapatite crystals were needle like, with a length of approximately 100-300 nm and a diameter of approximately 20-60 nm. The results of in vitro cell culture study using rat osteoblast cells demonstrated that the nonwoven silk fibroin net/nano-apatite composite showed excellent cytocompatibility for the growth of osteoblasts and had the capability to improve the viability of osteoblasts.

  13. Hydroxyapatite coating for titanium fibre mesh scaffold enhances osteoblast activity and bone tissue formation.

    PubMed

    Hirota, Makoto; Hayakawa, Tohru; Yoshinari, Masao; Ametani, Akihiro; Shima, Takaki; Monden, Yuka; Ozawa, Tomomichi; Sato, Mitsunobu; Koyama, Chika; Tamai, Naoto; Iwai, Toshinori; Tohnai, Iwai

    2012-10-01

    This study investigated the bone regeneration properties of titanium fibre mesh as a tissue engineering material. A thin hydroxyapatite (HA) coating on the titanium fibre web was created using the developed molecular precursor method without losing the complex interior structure. HA-coated titanium fibre mesh showed apatite crystal formation in vitro in a human osteoblast culture. Titanium fibre mesh discs with or without a thin HA coating were implanted into rat cranial bone defects, and the animals were killed at 2 and 4 weeks. The in vivo experience revealed that the amount of newly formed bone was significantly higher in the HA-coated titanium fibre mesh than in the non-coated titanium fibre mesh 2 weeks after implantation. These results suggest that thin HA coating enhances osteoblast activity and bone regeneration in the titanium fibre mesh scaffold. Thin HA-coating improved the ability of titanium fibre mesh to act as a bone regeneration scaffold.

  14. Development of hydroxyapatite scaffolds for artificial bone grafts

    NASA Astrophysics Data System (ADS)

    Ajaal, Tawfik Taher

    The Taguchi method of experimental design is very well suited to improving the production process of the synthetic bone grafts for several reasons. First, it is very efficient and easy to apply, so that it does not require large amounts of time or resources to conduct a given set of experiments. This makes it possible to conduct a series of experiments that result in continuous process improvement. Second, the effect of many different process variables can be examined simultaneously, which ensures that beneficial factor combinations are not overlooked. Finally, using a Taguchi signal-to-noise ratio leads to concurrent optimization of the process and reduction of process variability. The application of Taguchi method was successful in optimizing the production process of the synthetic bone grafts. The compressive strength was doubled while maintaining the appropriate porosity level and microstructure for the bioactivity process. The mean value of the compression strength obtained was 5.8 MPa with density of 0.515 gm/cm3 for samples prepared from 45 pores per inch (PPI) foam reticulate, and 3.2 MPa with 0.422 gm/cm 3 for samples prepared from 30 PPI foam reticulate. Three levels of porosity were identified namely, macro, meso, and micro-porosity. The pore sizes were (350--400) mum, (100--120) mum and (2--6) mum respectively based on the used substrate. Using the Taguchi method in conjunction with a statistical experimental design, the various steps of the scaffold production process such as slurry preparation, coating process, drying, calcining and sintering processes were optimized. The final optimized process gave highly reproducible results.

  15. Biomimetic fiber mesh scaffolds based on gelatin and hydroxyapatite nano-rods: Designing intrinsic skills to attain bone reparation abilities.

    PubMed

    Sartuqui, Javier; Gravina, A Noel; Rial, Ramón; Benedini, Luciano A; Yahia, L'Hocine; Ruso, Juan M; Messina, Paula V

    2016-09-01

    Intrinsic material skills have a deep effect on the mechanical and biological performance of bone substitutes, as well as on its associated biodegradation properties. In this work we have manipulated the preparation of collagenous derived fiber mesh frameworks to display a specific composition, morphology, open macroporosity, surface roughness and permeability characteristics. Next, the effect of the induced physicochemical attributes on the scaffold's mechanical behavior, bone bonding potential and biodegradability were evaluated. It was found that the scaffold microstructure, their inherent surface roughness, and the compression strength of the gelatin scaffolds can be modulated by the effect of the cross-linking agent and, essentially, by mimicking the nano-scale size of hydroxyapatite in natural bone. A clear effect of bioactive hydroxyapatite nano-rods on the scaffolds skills can be appreciated and it is greater than the effect of the cross-linking agent, offering a huge perspective for the upcoming progress of bone implant technology.

  16. Biomimetic fiber mesh scaffolds based on gelatin and hydroxyapatite nano-rods: Designing intrinsic skills to attain bone reparation abilities.

    PubMed

    Sartuqui, Javier; Gravina, A Noel; Rial, Ramón; Benedini, Luciano A; Yahia, L'Hocine; Ruso, Juan M; Messina, Paula V

    2016-09-01

    Intrinsic material skills have a deep effect on the mechanical and biological performance of bone substitutes, as well as on its associated biodegradation properties. In this work we have manipulated the preparation of collagenous derived fiber mesh frameworks to display a specific composition, morphology, open macroporosity, surface roughness and permeability characteristics. Next, the effect of the induced physicochemical attributes on the scaffold's mechanical behavior, bone bonding potential and biodegradability were evaluated. It was found that the scaffold microstructure, their inherent surface roughness, and the compression strength of the gelatin scaffolds can be modulated by the effect of the cross-linking agent and, essentially, by mimicking the nano-scale size of hydroxyapatite in natural bone. A clear effect of bioactive hydroxyapatite nano-rods on the scaffolds skills can be appreciated and it is greater than the effect of the cross-linking agent, offering a huge perspective for the upcoming progress of bone implant technology. PMID:27220014

  17. Functionalization of a Collagen-Hydroxyapatite Scaffold with Osteostatin to Facilitate Enhanced Bone Regeneration.

    PubMed

    Quinlan, Elaine; Thompson, Emmet M; Matsiko, Amos; O'Brien, Fergal J; López-Noriega, Adolfo

    2015-12-01

    Defects within bones caused by trauma and other pathological complications may often require the use of a range of therapeutics to facilitate tissue regeneration. A number of approaches have been widely utilized for the delivery of such therapeutics via physical encapsulation or chemical immobilization suggesting significant promise in the healing of bone defects. The study focuses on the chemical immobilization of osteostatin, a pentapeptide of the parathyroid hormone (PTHrP107-111), within a collagen-hydroxyapatite scaffold. The chemical attachment method via crosslinking supports as little as 4% release of the peptide from the scaffolds after 21 d whereas non-crosslinking leads to 100% of the peptide being released by as early as 4 d. In vitro characterization demonstrates that this cross-linking method of immobilization supports a pro-osteogenic effect on osteoblasts. Most importantly, when implanted in a critical-sized calvarial defect within a rat, these scaffolds promote significantly greater new bone volume and area compared to nonfunctionalized scaffolds (**p < 0.01) and an empty defect control (***p < 0.001). Collectively, this study suggests that such an approach of chemical immobilization offers greater spatiotemporal control over growth factors and can significantly modulate tissue regeneration. Such a system may be adopted for a range of different proteins and thus offers the potential for the treatment of various complex pathologies that require localized mediation of drug delivery.

  18. In situ mineralization of hydroxyapatite on electrospun chitosan-based nanofibrous scaffolds.

    PubMed

    Yang, Dongzhi; Jin, Yu; Zhou, Yingshan; Ma, Guiping; Chen, Xiangmei; Lu, Fengmin; Nie, Jun

    2008-03-10

    A biocomposite of hydroxyapatite (HAp) with electrospun nanofibrous scaffolds was prepared by using chitosan/polyvinyl alcohol (CS/PVA) and N-carboxyethyl chitosan/PVA (CECS/PVA) electrospun membranes as organic matrix, and HAp was formed in supersaturated CaCl2 and KH2PO4 solution. The influences of carboxylic acid groups in CECS/PVA fibrous scaffold and polyanionic additive poly(acrylic acid) (PAA) in the incubation solution on the crystal distribution of the HAp were investigated. Field-emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), wide-angle X-ray diffraction (WAXD), and Fourier transform infrared (FTIR) were used to characterize the morphology and structure of the deposited mineral phase on the scaffolds. It was found that addition of PAA to the mineral solution and use of matrix with carboxylic acid groups promoted mineral growth and distribution of HAp. MTT testing and SEM imaging from mouse fibroblast (L929) cell culture revealed the attachment and growth of mouse fibroblast on the surface of biocomposite scaffold, and that the cell morphology and viability were satisfactory for the composite to be used in bioapplications. PMID:18322911

  19. Multiscale fabrication of biomimetic scaffolds for tympanic membrane tissue engineering.

    PubMed

    Mota, Carlos; Danti, Serena; D'Alessandro, Delfo; Trombi, Luisa; Ricci, Claudio; Puppi, Dario; Dinucci, Dinuccio; Milazzo, Mario; Stefanini, Cesare; Chiellini, Federica; Moroni, Lorenzo; Berrettini, Stefano

    2015-06-01

    The tympanic membrane (TM) is a thin tissue able to efficiently collect and transmit sound vibrations across the middle ear thanks to the particular orientation of its collagen fibers, radiate on one side and circular on the opposite side. Through the combination of advanced scaffolds and autologous cells, tissue engineering (TE) could offer valuable alternatives to autografting in major TM lesions. In this study, a multiscale approach based on electrospinning (ES) and additive manufacturing (AM) was investigated to fabricate scaffolds, based on FDA approved copolymers, resembling the anatomic features and collagen fiber arrangement of the human TM. A single scale TM scaffold was manufactured using a custom-made collector designed to confer a radial macro-arrangement to poly(lactic-co-glycolic acid) electrospun fibers during their deposition. Dual and triple scale scaffolds were fabricated combining conventional ES with AM to produce poly(ethylene oxide terephthalate)/poly(butylene terephthalate) block copolymer scaffolds with anatomic-like architecture. The processing parameters were optimized for each manufacturing method and copolymer. TM scaffolds were cultured in vitro with human mesenchymal stromal cells, which were viable, metabolically active and organized following the anisotropic character of the scaffolds. The highest viability, cell density and protein content were detected in dual and triple scale scaffolds. Our findings showed that these biomimetic micro-patterned substrates enabled cell disposal along architectural directions, thus appearing as promising substrates for developing functional TM replacements via TE. PMID:25947357

  20. Bone Regeneration Using Hydroxyapatite Sponge Scaffolds with In Vivo Deposited Extracellular Matrix.

    PubMed

    Ventura, Reiza Dolendo; Padalhin, Andrew Reyes; Min, Young-Ki; Lee, Byong-Taek

    2015-11-01

    There is currently an increased interest in studying the extracellular matrix (ECM) and its potential applications for tissue engineering and regenerative medicine. The ECM plays an important role by providing adhesive substrates to cells during migration, morphogenesis, differentiation, and homeostasis by signaling biochemical and biomechanical cues to cells. In this study, the ECM was incorporated into hydroxyapatite by implanting sponge replica scaffolds in subcutaneous pockets in rats, and the implants were tested for bone regeneration potential. The resulting scaffolds were characterized using scanning electron microscopy, confocal microscopy, DNA and RNA quantification, tissue staining, energy dispersive X-ray spectroscopy analysis, compressive strength testing, porosity, and pore size distribution analysis using bare scaffolds as a control reference. Biocompatibility was assessed using MC3T3-E1 preosteoblast cells and in vivo studies were carried out by implanting decellularized scaffolds in 11 mm radial defects in New Zealand rabbits for 4 and 8 weeks to determine the effect of the in vivo deposited ECM. Material characterization indicated that a 2-week decellularized scaffold was the best among the samples, with an evenly distributed ECM visible on hematoxylin and eosin-stained tissue sections, a compressive strength of 2.53 ± 0.68 MPa, a porosity of 58.08 ± 3.32% and a pore size distribution range of 10-150 μm. In vivo results showed no severe inflammation, with increased cell infiltration followed by dense matrix deposition after 4 weeks and new bone formation at 8 weeks. The results indicate that incorporation of an in vivo deposited ECM into ceramic scaffolds can potentially improve bone regeneration.

  1. Characterization and in vivo evaluation of chitosan-hydroxyapatite bone scaffolds made by one step coprecipitation method.

    PubMed

    Danilchenko, Sergei N; Kalinkevich, Oksana V; Pogorelov, Maksim V; Kalinkevich, Aleksei N; Sklyar, Anatoly M; Kalinichenko, Tatyana G; Ilyashenko, Vyacheslav Y; Starikov, Vadim V; Bumeyster, Valentina I; Sikora, Vitaly Z; Sukhodub, Leonid F

    2011-03-15

    Chitosan/hydroxyapatite scaffolds could be used for bone regeneration in case the application of auto- or allografts is impossible. The objective of the present work was to characterize and study in vivo biodegradation of simple chitosan/hydroxyapatite scaffolds. For this purpose, a series of chitosan/hydroxyapatite composites has been synthesized in aqueous medium from chitosan solution and soluble precursor salts by a one step coprecipitation method. A study of in vivo behavior of the materials was then performed using model linear rats. Cylindrical-shaped rods made of the chitosan/hydroxyapatite composite material were implanted into tibial bones of the rats. After 5, 10, 15, and 24 days of implantation, histological and histo-morphometric analyses of decalcified specimens were performed to evaluate the stages of biodegradation processes. Calcified specimens were examined by scanning electron microscopy with X-ray microanalysis to compare elemental composition and morphological characteristics of the implant and the bone during integration. Porous chitosan/hydroxyapatite scaffolds have shown osteoconductive properties and have been replaced in the in vivo experiments by newly formed bone tissue. PMID:21268238

  2. PHBV/PLLA-based composite scaffolds fabricated using an emulsion freezing/freeze-drying technique for bone tissue engineering: surface modification and in vitro biological evaluation.

    PubMed

    Sultana, Naznin; Wang, Min

    2012-03-01

    Tissue engineering combines living cells with biodegradable materials and/or bioactive components. Composite scaffolds containing biodegradable polymers and nanosized osteoconductive bioceramic with suitable properties are promising for bone tissue regeneration. In this paper, based on blending two biodegradable and biocompatible polymers, namely poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(L-lactic acid) (PLLA) with incorporated nano hydroxyapatite (HA), three-dimensional composite scaffolds with controlled microstructures and an interconnected porous structure, together with high porosity, were fabricated using an emulsion freezing/freeze-drying technique. The influence of various parameters involved in the emulsion freezing/freeze-drying technique was studied for the fabrication of good-quality polymer scaffolds based on PHBV polymers. The morphology, mechanical properties and crystallinity of PHBV/PLLA and HA in PHBV/PLLA composite scaffolds and PHBV polymer scaffolds were studied. The scaffolds were coated with collagen in order to improve wettability. During in vitro biological evaluation study, it was observed that SaOS-2 cells had high attachment on collagen-coated scaffolds. Significant improvement in cell proliferation and alkaline phosphatase activity for HA-incorporated composite scaffolds was observed due to the incorporation of HA. After 3 and 7 days of culture on all scaffolds, SaOS-2 cells also had normal morphology and growth. These results indicated that PHBV/PLLA-based scaffolds fabricated via an emulsion freezing/freeze-drying technique were favorable sites for osteoblastic cells and are promising for the applications of bone tissue engineering.

  3. Alginate/nanohydroxyapatite scaffolds with designed core/shell structures fabricated by 3D plotting and in situ mineralization for bone tissue engineering.

    PubMed

    Luo, Yongxiang; Lode, Anja; Wu, Chengtie; Chang, Jiang; Gelinsky, Michael

    2015-04-01

    Composite scaffolds, especially polymer/hydroxyapatite (HAP) composite scaffolds with predesigned structures, are promising materials for bone tissue engineering. Various methods including direct mixing of HAP powder with polymers or incubating polymer scaffolds in simulated body fluid for preparing polymer/HAP composite scaffolds are either uncontrolled or require long times of incubation. In this work, alginate/nano-HAP composite scaffolds with designed pore parameters and core/shell structures were fabricated using 3D plotting technique and in situ mineralization under mild conditions (at room temperature and without the use of any organic solvents). Light microscopy, scanning electron microscopy, microcomputer tomography, X-ray diffraction, and Fourier transform infrared spectroscopy were applied to characterize the fabricated scaffolds. Mechanical properties and protein delivery of the scaffolds were evaluated, as well as the cell response to the scaffolds by culturing human bone-marrow-derived mesenchymal stem cells (hBMSC). The obtained data indicate that this method is suitable to fabricate alginate/nano-HAP composite scaffolds with a layer of nano-HAP, coating the surface of the alginate strands homogeneously and completely. The surface mineralization enhanced the mechanical properties and improved the cell attachment and spreading, as well as supported sustaining protein release, compared to pure alginate scaffolds without nano-HAP shell layer. The results demonstrated that the method provides an interesting option for bone tissue engineering application.

  4. Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

    PubMed

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

    2015-08-01

    Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water.

  5. Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

    PubMed

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

    2015-08-01

    Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water. PMID:26369193

  6. Excavating the Role of Aloe Vera Wrapped Mesoporous Hydroxyapatite Frame Ornamentation in Newly Architectured Polyurethane Scaffolds for Osteogenesis and Guided Bone Regeneration with Microbial Protection.

    PubMed

    Selvakumar, M; Pawar, Harpreet Singh; Francis, Nimmy K; Das, Bodhisatwa; Dhara, Santanu; Chattopadhyay, Santanu

    2016-03-01

    Guided bone regeneration (GBR) scaffolds are unsuccessful in many clinical applications due to a high incidence of postoperative infection. The objective of this work is to fabricate GBR with an anti-infective electrospun scaffold by ornamenting segmented polyurethane (SPU) with two-dimensional Aloe vera wrapped mesoporous hydroxyapatite (Al-mHA) nanorods. The antimicrobial characteristic of the scaffold has been retrieved from the prepared Al-mHA frame with high aspect ratio (∼14.2) via biosynthesis route using Aloe vera (Aloe barbadensis miller) extract. The Al-mHA frame was introduced into an unprecedented SPU matrix (solution polymerized) based on combinatorial soft segments of poly(ε-caprolactone) (PCL), poly(ethylene carbonate) (PEC), and poly(dimethylsiloxane) (PDMS), by an in situ technique followed by electrospinning to fabricate scaffolds. For comparison, pristine mHA nanorods are also ornamented into it. An enzymatic ring-opening polymerization technique was adapted to synthesize soft segment of (PCL-PEC-b-PDMS). Structure elucidation of the synthesized polymers is established by nuclear magnetic resonance spectroscopy. Sparingly, Al-mHA ornamented scaffolds exhibit tremendous improvement (175%) in the mechanical properties with promising antimicrobial activity against various human pathogens. After confirmation of high osteoconductivity, improved biodegradation, and excellent biocompatibility against osteoblast-like MG63 cells (in vitro), the scaffolds were implanted in rabbits as an animal model by subcutaneous and intraosseous (tibial) sites. Improved in vivo biocompatibilities, biodegradation, osteoconductivity, and the ability to provide an adequate biomimetic environment for biomineralization for GBR of the scaffolds (SPU and ornamented SPUs) have been found from the various histological sections. Early cartilage formation, endochondral ossification, and rapid bone healing at 4 weeks were found in the defects filled with Al-mHA ornamented

  7. Excavating the Role of Aloe Vera Wrapped Mesoporous Hydroxyapatite Frame Ornamentation in Newly Architectured Polyurethane Scaffolds for Osteogenesis and Guided Bone Regeneration with Microbial Protection.

    PubMed

    Selvakumar, M; Pawar, Harpreet Singh; Francis, Nimmy K; Das, Bodhisatwa; Dhara, Santanu; Chattopadhyay, Santanu

    2016-03-01

    Guided bone regeneration (GBR) scaffolds are unsuccessful in many clinical applications due to a high incidence of postoperative infection. The objective of this work is to fabricate GBR with an anti-infective electrospun scaffold by ornamenting segmented polyurethane (SPU) with two-dimensional Aloe vera wrapped mesoporous hydroxyapatite (Al-mHA) nanorods. The antimicrobial characteristic of the scaffold has been retrieved from the prepared Al-mHA frame with high aspect ratio (∼14.2) via biosynthesis route using Aloe vera (Aloe barbadensis miller) extract. The Al-mHA frame was introduced into an unprecedented SPU matrix (solution polymerized) based on combinatorial soft segments of poly(ε-caprolactone) (PCL), poly(ethylene carbonate) (PEC), and poly(dimethylsiloxane) (PDMS), by an in situ technique followed by electrospinning to fabricate scaffolds. For comparison, pristine mHA nanorods are also ornamented into it. An enzymatic ring-opening polymerization technique was adapted to synthesize soft segment of (PCL-PEC-b-PDMS). Structure elucidation of the synthesized polymers is established by nuclear magnetic resonance spectroscopy. Sparingly, Al-mHA ornamented scaffolds exhibit tremendous improvement (175%) in the mechanical properties with promising antimicrobial activity against various human pathogens. After confirmation of high osteoconductivity, improved biodegradation, and excellent biocompatibility against osteoblast-like MG63 cells (in vitro), the scaffolds were implanted in rabbits as an animal model by subcutaneous and intraosseous (tibial) sites. Improved in vivo biocompatibilities, biodegradation, osteoconductivity, and the ability to provide an adequate biomimetic environment for biomineralization for GBR of the scaffolds (SPU and ornamented SPUs) have been found from the various histological sections. Early cartilage formation, endochondral ossification, and rapid bone healing at 4 weeks were found in the defects filled with Al-mHA ornamented

  8. 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

  9. Control of the pore architecture in three-dimensional hydroxyapatite-reinforced hydrogel scaffolds

    NASA Astrophysics Data System (ADS)

    Román, Jesús; Cabañas, María Victoria; Peña, Juan; Vallet-Regí, María

    2011-08-01

    Hydrogels (gellan or agarose) reinforced with nanocrystalline carbonated hydroxyapatite (nCHA) were prepared by the GELPOR3D technique. This simple method is characterized by compositional flexibility; it does not require expensive equipment, thermal treatment, or aggressive or toxic solvents, and yields a three-dimensional (3D) network of interconnected pores 300-900 μm in size. In addition, an interconnected porosity is generated, yielding a hierarchical porous architecture from the macro to the molecular scale. This porosity depends on both the drying/preservation technology (freeze drying or oven drying at 37 circleC) and on the content and microstructure of the reinforcing ceramic. For freeze-dried samples, the porosities were approximately 30, 66 and below 3% for pore sizes of 600-900 μm, 100-200 μm and 50-100 nm, respectively. The pore structure depends much on the ceramic content, so that higher contents lead to the disappearance of the characteristic honeycomb structure observed in low-ceramic scaffolds and to a lower fraction of the 100-200-μm-sized pores. The nature of the hydrogel did not affect the pore size distribution but was crucial for the behavior of the scaffolds in a hydrated medium: gellan-containing scaffolds showed a higher swelling degree owing to the presence of more hydrophilic groups.

  10. Assisted deposition of nano-hydroxyapatite onto exfoliated carbon nanotube oxide scaffolds

    NASA Astrophysics Data System (ADS)

    Zanin, H.; Rosa, C. M. R.; Eliaz, N.; May, P. W.; Marciano, F. R.; Lobo, A. O.

    2015-05-01

    Electrodeposited nano-hydroxyapatite (nHAp) is more similar to biological apatite in terms of microstructure and dimension than apatites prepared by other processes. Reinforcement with carbon nanotubes (CNTs) enhances its mechanical properties and increases adhesion of osteoblasts. Here, we carefully studied nHAp deposited onto vertically aligned multi-walled CNT (VAMWCNT) scaffolds by electrodeposition and soaking in a simulated body fluid (SBF). VAMWCNTs are porous biocompatible scaffolds with nanometric porosity and exceptional mechanical and chemical properties. The VAMWCNT films were prepared on a Ti substrate by a microwave plasma chemical vapour deposition method, and then oxidized and exfoliated by oxygen plasma etching (OPE) to produce graphene oxide (GO) at the VAMWCNT tips. The attachment of oxygen functional groups was found to be crucial for nHAp nucleation during electrodeposition. A thin layer of plate-like and needle-like nHAp with high crystallinity was formed without any need for thermal treatment. This composite (henceforth referred to as nHAp-VAMWCNT-GO) served as the scaffold for in vitro biomineralization when soaked in the SBF, resulting in the formation of both carbonate-rich and carbonate-poor globular-like nHAp. Different steps in the deposition of biological apatite onto VAMWCNT-GO and during the short-term biomineralization process were analysed. Due to their unique structure and properties, such nano-bio-composites may become useful in accelerating in vivo bone regeneration processes.

  11. Fabrication of Bioceramic Bone Scaffolds for Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Liu, Fwu-Hsing

    2014-10-01

    In this study, microhydroxyapatite and nanosilica sol were used as the raw materials for fabrication of bioceramic bone scaffold using selective laser sintering technology in a self-developed 3D Printing apparatus. When the fluidity of ceramic slurry is matched with suitable laser processing parameters, a controlled pore size of porous bone scaffold can be fabricated under a lower laser energy. Results shown that the fabricated scaffolds have a bending strength of 14.1 MPa, a compressive strength of 24 MPa, a surface roughness of 725 nm, a pore size of 750 μm, an apparent porosity of 32%, and a optical density of 1.8. Results indicate that the mechanical strength of the scaffold can be improved after heat treatment at 1200 °C for 2 h, while simultaneously increasing surface roughness conducive to osteoprogenitor cell adhesion. MTT method and SEM observations confirmed that bone scaffolds fabricated under the optimal manufacturing process possess suitable biocompatibility and mechanical properties, allowing smooth adhesion and proliferation of osteoblast-like cells. Therefore, they have great potential for development in the field of tissue engineering.

  12. Development of gelatin-chitosan-hydroxyapatite based bioactive bone scaffold with controlled pore size and mechanical strength.

    PubMed

    Maji, Kanchan; Dasgupta, Sudip; Kundu, Biswanath; Bissoyi, Akalabya

    2015-01-01

    Hydroxyapatite-chitosan/gelatin (HA:Chi:Gel) nanocomposite scaffold has potential to serve as a template matrix to regenerate extra cellular matrix of human bone. Scaffolds with varying composition of hydroxyapatite, chitosan, and gelatin were prepared using lyophilization technique where glutaraldehyde (GTA) acted as a cross-linking agent for biopolymers. First, phase pure hydroxyapatite-chitosan nanocrystals were in situ synthesized by coprecipitation method using a solution of 2% acetic acid dissolved chitosan and aqueous solution of calcium nitrate tetrahydrate [Ca(NO3)2,4H2O] and diammonium hydrogen phosphate [(NH4)2H PO4]. Keeping solid loading constant at 30 wt% and changing the composition of the original slurry of gelatin, HA-chitosan allowed control of the pore size, its distribution, and mechanical properties of the scaffolds. Microstructural investigation by scanning electron microscopy revealed the formation of a well interconnected porous scaffold with a pore size in the range of 35-150 μm. The HA granules were uniformly dispersed in the gelatin-chitosan network. An optimal composition in terms of pore size and mechanical properties was obtained from the scaffold with an HA:Chi:Gel ratio of 21:49:30. The composite scaffold having 70% porosity with pore size distribution of 35-150 μm exhibited a compressive strength of 3.3-3.5 MPa, which is within the range of that exhibited by cancellous bone. The bioactivity of the scaffold was evaluated after conducting mesenchymal stem cell (MSC) - materials interaction and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay using MSCs. The scaffold found to be conducive to MSC's adhesion as evident from lamellipodia, filopodia extensions from cell cytoskeleton, proliferation, and differentiation up to 14 days of cell culture.

  13. In Vitro and In Vivo investigations on fibronectin coated and hydroxyapatite incorporated scaffolds.

    PubMed

    Mohamadyar-Toupkanlou, F; Vasheghani-Farahani, E; Bakhshandeh, B; Soleimani, M; Ardeshirylajimi, A

    2015-01-01

    Topological and biochemical aspects of the matrices are essential factors to be extensively studied for more successful tissue engineering. Other characteristics including biodegradability and biocompatibility should be also considered. Nanofibrous structure mimics topography of the natural matrix. Previous in vitro studies reported the favorable effects of nanohydroxyapatite (nHA) and fibronectin (Fn) on biodegradability and biocompatibility of scaffold. Herein, the synergistic outcome of co-application of Fn and nHA incorporation into aligned electrospun polycaprolactone (PCL) seeded by mouse mesenchymal stem cells (MSC) was investigated both in vitro and in vivo. Scanning Electron Microscopy (SEM), contact angle measurement and tensile test were applied for scaffold characterization. In vitro evaluation of the seeded cells was performed by MTT, SEM and cell-cycle analyses. In congruence with in vitro findings, in vivo assessment of four weeks fibronectin coated PCL/ nHA scaffold transplanted mice illustrated the suitable compact surrounding tissue with the most penetrated cells generation. Furthermore, Fn coating resulted in cell infiltration enhancement while nHA addition led to more scaffold biodegradation. In conclusion, fabrication of nanofiberous scaffold with this combination of biochemical composition and surface stimulation caused improved biodegradability and biocompatibility of the scaffold which are desirable in more effective tissue regeneration. PMID:26255261

  14. The influence of plasma technology coupled to chemical grafting on the cell growth compliance of 3D hydroxyapatite scaffolds.

    PubMed

    Russo, Laura; Zanini, Stefano; Giannoni, Paolo; Landi, Elena; Villa, Anna; Sandri, Monica; Riccardi, Claudia; Quarto, Rodolfo; Doglia, Silvia M; Nicotra, Francesco; Cipolla, Laura

    2012-11-01

    The development of advanced materials with biomimetic features in order to elicit desired biological responses and to guarantee tissue biocompatibility is recently gaining attention for tissue engineering applications. Bioceramics, such as hydroxyapatite-based biomaterials are now used in a number of different applications throughout the body, covering all areas of the skeleton, due to their biological and chemical similarity to the inorganic phases of bones. When bioactive sintered hydroxyapatite (HA) is desired, biomolecular modification of these materials is needed. In the present work, we investigated the influence of plasma surface modification coupled to chemical grafting on the cell growth compliance of HA 3D scaffolds.

  15. Effects of hydroxyapatite nanostructure on channel surface of porcine acellular dermal matrix scaffold on cell viability and osteogenic differentiation of human periodontal ligament stem cells.

    PubMed

    Ge, Shaohua; Zhao, Ning; Wang, Lu; Liu, Hong; Yang, Pishan

    2013-01-01

    A new nanostructured hydroxyapatite-coated porcine acellular dermal matrix (HAp-PADM) was fabricated by a biomimetic mineralization method. Human periodontal ligament stem cells were seeded on HAp-PADM and the effects of this scaffold on cell shape, cytoskeleton organization, cell viability, and osteogenic differentiation were examined. Periodontal ligament stem cells cultured on HAp-PADM exhibited different cell shape when compared with those on pure PADM. Moreover, HAp-PADM promoted cell viability and alkaline phosphatase activity significantly. Based on quantitative real-time polymerase chain reaction, the expression of bone-related markers runt-related transcription factor 2 (Runx2), osteopontin (OPN), and osteocalcin (OCN) upregulated in the HAp-PADM scaffold. The enhancement of osteogenic differentiation of periodontal ligament stem cells on the HAp-PADM scaffold was proposed based on the research results. The results of this study highlight the micro-nano, two-level, three-dimensional HAp-PADM composite as a promising scaffold for periodontal tissue engineering.

  16. Fabrication and Application of Nanofibrous Scaffolds in Tissue Engineering

    PubMed Central

    Li, Wan-Ju; Tuan, Rocky S.

    2009-01-01

    Nanofibers fabricated by electrospinning are morphological mimics of fibrous components of the native extracellular matrix, making nanofibrous scaffolds ideal for three-dimensional cell culture and tissue engineering applications. Although electrospinning is not a conventional technique in cell biology, the experimental set-up may be constructed in a relatively straightforward manner and the procedure can be carried by individuals with limited engineering experience. We detail here a protocol for electrospinning of nanofibers and provide relevant specific details concerning the optimization of fiber formation. The protocol also includes conditions required for preparing biodegradable polymer solutions for the fabrication of non-woven and aligned nanofibrous scaffolds suitable for various cell/tissue applications. In addition, the information on effective cell loading into nanofibrous scaffolds is provided. Instructions for building the electrospinning apparatus are also included. PMID:19283731

  17. Fabrication, Properties and Applications of Dense Hydroxyapatite: A Review.

    PubMed

    Prakasam, Mythili; Locs, Janis; Salma-Ancane, Kristine; Loca, Dagnija; Largeteau, Alain; Berzina-Cimdina, Liga

    2015-12-21

    In the last five decades, there have been vast advances in the field of biomaterials, including ceramics, glasses, glass-ceramics and metal alloys. Dense and porous ceramics have been widely used for various biomedical applications. Current applications of bioceramics include bone grafts, spinal fusion, bone repairs, bone fillers, maxillofacial reconstruction, etc. Amongst the various calcium phosphate compositions, hydroxyapatite, which has a composition similar to human bone, has attracted wide interest. Much emphasis is given to tissue engineering, both in porous and dense ceramic forms. The current review focusses on the various applications of dense hydroxyapatite and other dense biomaterials on the aspects of transparency and the mechanical and electrical behavior. Prospective future applications, established along the aforesaid applications of hydroxyapatite, appear to be promising regarding bone bonding, advanced medical treatment methods, improvement of the mechanical strength of artificial bone grafts and better in vitro/in vivo methodologies to afford more particular outcomes.

  18. Fabrication, Properties and Applications of Dense Hydroxyapatite: A Review

    PubMed Central

    Prakasam, Mythili; Locs, Janis; Salma-Ancane, Kristine; Loca, Dagnija; Largeteau, Alain; Berzina-Cimdina, Liga

    2015-01-01

    In the last five decades, there have been vast advances in the field of biomaterials, including ceramics, glasses, glass-ceramics and metal alloys. Dense and porous ceramics have been widely used for various biomedical applications. Current applications of bioceramics include bone grafts, spinal fusion, bone repairs, bone fillers, maxillofacial reconstruction, etc. Amongst the various calcium phosphate compositions, hydroxyapatite, which has a composition similar to human bone, has attracted wide interest. Much emphasis is given to tissue engineering, both in porous and dense ceramic forms. The current review focusses on the various applications of dense hydroxyapatite and other dense biomaterials on the aspects of transparency and the mechanical and electrical behavior. Prospective future applications, established along the aforesaid applications of hydroxyapatite, appear to be promising regarding bone bonding, advanced medical treatment methods, improvement of the mechanical strength of artificial bone grafts and better in vitro/in vivo methodologies to afford more particular outcomes. PMID:26703750

  19. Fabrication of cancellous biomimetic chitosan-based nanocomposite scaffolds applying a combinational method for bone tissue engineering.

    PubMed

    Jamalpoor, Zahra; Mirzadeh, Hamid; Joghataei, Mohammad Taghi; Zeini, Darya; Bagheri-Khoulenjani, Shadab; Nourani, Mohammad Reza

    2015-05-01

    The aim of this study was to mimic the specific structure of bone and fabricate a biomimetic nano-hydroxyapatite (HA)/chitosan (Cs)/gelatin scaffolds using combination of particle leaching and freeze drying methods eliminating mold effects. To achieve an optimum structure, scaffolds with different gelatin/Cs weight ratio were fabricated. Morphological characterization of scaffolds by scanning electron microscopy method showed highly interconnected porous structures similar to cancellous bone with mean pore size ranging from 140 to 190 μm. Nano-HA crystals were dispersed homogeneously in the polymer matrix according to the energy-dispersive X-ray spectroscopy and transmission electron microscopy images. Fourier transform infrared and X-ray diffraction results disclosed that chemical interactions were formed between nano-HA, Cs, gelatin and crystallinity of each material decreased with blending. It was found that increasing the gelatin content significantly improved water uptake, degradation rate as well as attachment, infiltration and proliferation of Saos2 cells to the scaffolds. The presented results confirm that the designed biomimetic nano-HA /Cs/gelatin scaffolds can be used as promising substitutes for bone tissue engineering.

  20. Enhanced sintering ability of biphasic calcium phosphate by polymers used for bone scaffold fabrication.

    PubMed

    Gao, Chengde; Yang, Bo; Hu, Huanlong; Liu, Jinglin; Shuai, Cijun; Peng, Shuping

    2013-10-01

    Biphasic calcium phosphate (BCP), which is composed of hydroxyapatite [HAP, Ca10(PO4)6(OH)2] and β-tricalcium phosphate [β-TCP, β-Ca3(PO4)2], is usually difficult to densify into a solid state with selective laser sintering (SLS) due to the short sintering time. In this study, the sintering ability of BCP ceramics was significantly improved by adding a small amount of polymers, by which a liquid phase was introduced during the sintering process. The effects of the polymer content, laser power and HAP/β-TCP ratios on the microstructure, chemical composition and mechanical properties of the BCP scaffolds were investigated. The results showed that the BCP scaffolds became increasingly more compact with the increase of the poly(l-lactic acid) (PLLA) content (0-1 wt.%) and laser power (6-10 W). The fracture toughness and micro-hardness of the sintered scaffolds were also improved. Moreover, PLLA could be gradually decomposed in the late sintering stages and eliminated from the final BCP scaffolds if the PLLA content was below a certain value (approximately 1 wt.% in this case). The added PLLA could not be completely eliminated when its content was further increased to 1.5 wt.% or higher because an unexpected carbon phase was detected in the sintered scaffolds. Furthermore, many pores were observed due to the removal of PLLA. Micro-cracks and micro-pores occurred when the laser power was too high (12 W). These defects resulted in a deterioration of the mechanical properties. The hardness and fracture toughness reached maximum values of 490.3±10 HV and 1.72±0.10 MPa m(1/2), respectively, with a PLLA content of approximately 1 wt.% and laser power of approximately 10 W. Poly(l-lactic-co-glycolic acid) (PLGA) showed similar effects on the sintering process of BCP ceramics. Rectangular, porous BCP scaffolds were fabricated based on the optimum values of the polymer content and laser power. This work may provide an experimental basis for improving the mechanical

  1. Extraction and characterization of biocompatible hydroxyapatite from fresh water fish scales for tissue engineering scaffold.

    PubMed

    Panda, Niladri Nath; Pramanik, Krishna; Sukla, Lala Behari

    2014-03-01

    In bone tissue engineering, porous hydroxyapatite (HAp) is used as filling material for bone defects, augmentation, artificial bone graft and scaffold material. The present paper compares the preparation and characterization of HAp from fish scale (FS) and synthetic body fluid (SBF) solution. Thermo gravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and particle size analysis of the samples have been performed. The analysis indicates that synthesized HAp consists of sub-micron HAp particle with Ca/P ratio corresponding to FS and SBF 1.62 and 1.71, respectively. MTT assay and quantitative DNA analysis show growth and proliferation of cells over the HA scaffold with the increase in time. The shape and size (morphology) of mesenchymal stem cells after 3 days show a transition from rounded shape to elongated and flattened shape expressing its spreading behavior. These results confirm that HAp bio-materials from fish scale are physico-chemically and biologically equivalent to the chemically synthesized HAp from SBF. Biological HAp, thus, possesses a great potential for conversion of industrial by-product into highly valuable compounds using simple effective and novel processes.

  2. A novel two-step sintering for nano-hydroxyapatite scaffolds for bone tissue engineering

    PubMed Central

    Feng, Pei; Niu, Man; Gao, Chengde; Peng, Shuping; Shuai, Cijun

    2014-01-01

    In this study, nano-hydroxyapatite scaffolds with high mechanical strength and an interconnected porous structure were prepared using NTSS for the first time. The first step was performed using a laser characterized by the rapid heating to skip the surface diffusion and to obtain the driving force for grain boundary diffusion. Additionally, the interconnected porous structure was achieved by SLS. The second step consisted of isothermal heating in a furnace at a lower temperature (T2) than that of the laser beam to further increase the density and to suppress grain growth by exploiting the difference in kinetics between grain-boundary diffusion and grain-boundary migration. The results indicated that the mechanical properties first increased and then decreased as T2 was increased from 1050 to 1250°C. The optimal fracture toughness, compressive strength and stiffness were 1.69 MPam1/2, 18.68 MPa and 245.79 MPa, respectively. At the optimal point, the T2 was 1100°C, the grain size was 60 nm and the relative density was 97.6%. The decrease in mechanical properties was due to the growth of grains and the decomposition of HAP. The cytocompatibility test results indicated that cells adhered and spread well on the scaffolds. A bone-like apatite layer formed, indicating good bioactivity. PMID:24998362

  3. Polycaprolactone Scaffolds Fabricated via Bioextrusion for Tissue Engineering Applications

    PubMed Central

    Domingos, Marco; Dinucci, Dinuccio; Cometa, Stefania; Alderighi, Michele; Bártolo, Paulo Jorge; Chiellini, Federica

    2009-01-01

    The most promising approach in Tissue Engineering involves the seeding of porous, biocompatible/biodegradable scaffolds, with donor cells to promote tissue regeneration. Additive biomanufacturing processes are increasingly recognized as ideal techniques to produce 3D structures with optimal pore size and spatial distribution, providing an adequate mechanical support for tissue regeneration while shaping in-growing tissues. This paper presents a novel extrusion-based system to produce 3D scaffolds with controlled internal/external geometry for TE applications.The BioExtruder is a low-cost system that uses a proper fabrication code based on the ISO programming language enabling the fabrication of multimaterial scaffolds. Poly(ε-caprolactone) was the material chosen to produce porous scaffolds, made by layers of directionally aligned microfilaments. Chemical, morphological, and in vitro biological evaluation performed on the polymeric constructs revealed a high potential of the BioExtruder to produce 3D scaffolds with regular and reproducible macropore architecture, without inducing relevant chemical and biocompatibility alterations of the material. PMID:20126577

  4. Micromechanical finite-element modeling and experimental characterization of the compressive mechanical properties of polycaprolactone-hydroxyapatite composite scaffolds prepared by selective laser sintering for bone tissue engineering.

    PubMed

    Eshraghi, Shaun; Das, Suman

    2012-08-01

    Bioresorbable scaffolds with mechanical properties suitable for bone tissue engineering were fabricated from polycaprolactone (PCL) and hydroxyapatite (HA) by selective laser sintering (SLS) and modeled by finite-element analysis (FEA). Both solid gage parts and scaffolds having 1-D, 2-D and 3-D orthogonal, periodic porous architectures were made with 0, 10, 20 and 30 vol.% HA. PCL:HA scaffolds manufactured by SLS had nearly full density (99%) in the designed solid regions and had excellent geometric and dimensional control. Through optimization of the SLS process, the compressive moduli for our solid gage parts and scaffolds are the highest reported in the literature for additive manufacturing. The compressive moduli of solid gage parts were 299.3, 311.2, 415.5 and 498.3 MPa for PCL:HA loading at 100:0, 90:10, 80:20 and 70:30, respectively. The compressive effective stiffness tended to increase as the loading of HA was increased and the designed porosity was lowered. In the case of the most 3-D porous scaffold, the compressive modulus more than doubled from 14.9 to 36.2 MPa when changing the material from 100:0 to 70:30 PCL:HA. A micromechanical FEA model was developed to investigate the reinforcement effect of HA loading on the compressive modulus of the bulk material. Using a first-principles based approach, the random distribution of HA particles in a solidified PCL matrix was modeled for any HA loading to predict the bulk mechanical properties of the composites. The bulk mechanical properties were also used for FEA of the scaffold geometries. The results of the FEA were found to be in good agreement with experimental mechanical testing. The development of patient- and site-specific composite tissue-engineering constructs with tailored properties can be seen as a direct extension of this work on computational design, a priori modeling of mechanical properties and direct digital manufacturing.

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  6. Mineralization and drug release of hydroxyapatite/poly(l-lactic acid) nanocomposite scaffolds prepared by Pickering emulsion templating.

    PubMed

    Hu, Yang; Zou, Shengwen; Chen, Weike; Tong, Zhen; Wang, Chaoyang

    2014-10-01

    Biodegradable and bioactive nanocomposite (NC) biomaterials with controlled microstructures and able to deliver special drugs have gained increasing attention in bone tissue engineering. In this study, the hydroxyapatite (HAp)/poly(l-lactic acid) (PLLA) NC scaffolds were facilely prepared using solvent evaporation from templating Pickering emulsions stabilized with PLLA-modified HAp (g-HAp) nanoparticles. Then, in vitro mineralization experiments were performed in a simulated body fluid (SBF) to evaluate the bioactivity of the NC scaffolds. Moreover, in vitro drug release of the NC scaffolds using anti-inflammatory drug (ibuprofen, IBU) as the model drug was also investigated. The results showed that the NC scaffolds possessed interconnected pore structures, which could be modulated by varying the g-HAp nanoparticle concentration. The NC scaffolds exhibited excellent bioactivity, since they induced the formation of calcium-sufficient, carbonated apatite nanoparticles on the scaffolds after mineralization in SBF for 3 days. The IBU loaded in the NC scaffolds showed a sustained release profile, and the release kinetic followed the Higuchi model with diffusion process. Thus, solvent evaporation based on Pickering emulsion droplets is a simple and effective method to prepare biodegradable and bioactive porous NC scaffolds for bone repair and replacement applications.

  7. Formation of Neural Networks in 3D Scaffolds Fabricated by Means of Laser Microstereolithography.

    PubMed

    Vedunova, M V; Timashev, P S; Mishchenko, T A; Mitroshina, E V; Koroleva, A V; Chichkov, B N; Panchenko, V Ya; Bagratashvili, V N; Mukhina, I V

    2016-08-01

    We developed and tested new 3D scaffolds for neurotransplantation. Scaffolds of predetermined architectonic were prepared using microstereolithography technique. Scaffolds were highly biocompatible with the nervous tissue cells. In vitro studies showed that the material of fabricated scaffolds is not toxic for dissociated brain cells and promotes the formation of functional neural networks in the matrix. These results demonstrate the possibility of fabrication of tissue-engineering constructs for neurotransplantation based on created scaffolds. PMID:27595153

  8. Fabrication and Microstructure of Hydroxyapatite Coatings on Zirconia by Room Temperature Spray Process.

    PubMed

    Seo, Dong Seok; Chae, Hak Cheol; Lee, Jong Kook

    2015-08-01

    Hydroxyapatite coatings were fabricated on zirconia substrates by a room temperature spray process and were investigated with regards to their microstructure, composition and dissolution in water. An initial hydroxyapatite powder was prepared by heat treatment of bovine-bone derived powder at 1100 °C for 2 h, while dense zirconia substrates were fabricated by pressing 3Y-TZP powder and sintering it at 1350 °C for 2 h. Room temperature spray coating was performed using a slit nozzle in a low pressure-chamber with a controlled coating time. The phase composition of the resultant hydroxyapatite coatings was similar to that of the starting powder, however, the grain size of the hydroxyapatite particles was reduced to about 100 nm due to their formation by particle impaction and fracture. All areas of the coating had a similar morphology, consisting of reticulated structure with a high surface roughness. The hydroxyapatite coating layer exhibited biostability in a stimulated body fluid, with no severe dissolution being observed during in vitro experimentation.

  9. Fabrication and Microstructure of Hydroxyapatite Coatings on Zirconia by Room Temperature Spray Process.

    PubMed

    Seo, Dong Seok; Chae, Hak Cheol; Lee, Jong Kook

    2015-08-01

    Hydroxyapatite coatings were fabricated on zirconia substrates by a room temperature spray process and were investigated with regards to their microstructure, composition and dissolution in water. An initial hydroxyapatite powder was prepared by heat treatment of bovine-bone derived powder at 1100 °C for 2 h, while dense zirconia substrates were fabricated by pressing 3Y-TZP powder and sintering it at 1350 °C for 2 h. Room temperature spray coating was performed using a slit nozzle in a low pressure-chamber with a controlled coating time. The phase composition of the resultant hydroxyapatite coatings was similar to that of the starting powder, however, the grain size of the hydroxyapatite particles was reduced to about 100 nm due to their formation by particle impaction and fracture. All areas of the coating had a similar morphology, consisting of reticulated structure with a high surface roughness. The hydroxyapatite coating layer exhibited biostability in a stimulated body fluid, with no severe dissolution being observed during in vitro experimentation. PMID:26369194

  10. Chondrogenic regeneration using bone marrow clots and a porous polycaprolactone-hydroxyapatite scaffold by three-dimensional printing.

    PubMed

    Yao, Qingqiang; Wei, Bo; Liu, Nancy; Li, Chenshuang; Guo, Yang; Shamie, Arya Nick; Chen, James; Tang, Cheng; Jin, Chengzhe; Xu, Yan; Bian, Xiuwu; Zhang, Xinli; Wang, Liming

    2015-04-01

    Scaffolds play an important role in directing three-dimensional (3D) cartilage regeneration. Our recent study reported the potential advantages of bone marrow clots (MC) in promoting extracellular matrix (ECM) scaffold chondrogenic regeneration. The aim of this study is to build a new scaffold for MC, with improved characteristics in mechanics, shaping, and biodegradability, compared to our previous study. To address this issue, this study prepared a 3D porous polycaprolactone (PCL)-hydroxyapatite (HA) scaffold combined with MC (Group A), while the control group (Group B) utilized a bone marrow stem cell seeded PCL-HA scaffold. The results of in vitro cultures and in vivo implantation demonstrated that although an initial obstruction of nutrient exchange caused by large amounts of fibrin and erythrocytes led to a decrease in the ratio of live cells in Group A, these scaffolds also showed significant improvements in cell adhesion, proliferation, and chondrogenic differentiation with porous recanalization in the later culture, compared to Group B. After 4 weeks of in vivo implantation, Group A scaffolds have a superior performance in DNA content, Sox9 and RunX2 expression, cartilage lacuna-like cell and ECM accumulation, when compared to Group B. Furthermore, Group A scaffold size and mechanics were stable during in vitro and in vivo experiments, unlike the scaffolds in our previous study. Our results suggest that the combination with MC proved to be a highly efficient, reliable, and simple new method that improves the biological performance of 3D PCL-HA scaffold. The MC-PCL-HA scaffold is a candidate for future cartilage regeneration studies.

  11. Chondrogenic Regeneration Using Bone Marrow Clots and a Porous Polycaprolactone-Hydroxyapatite Scaffold by Three-Dimensional Printing

    PubMed Central

    Yao, Qingqiang; Wei, Bo; Liu, Nancy; Li, Chenshuang; Guo, Yang; Shamie, Arya Nick; Chen, James; Tang, Cheng; Jin, Chengzhe; Xu, Yan

    2015-01-01

    Scaffolds play an important role in directing three-dimensional (3D) cartilage regeneration. Our recent study reported the potential advantages of bone marrow clots (MC) in promoting extracellular matrix (ECM) scaffold chondrogenic regeneration. The aim of this study is to build a new scaffold for MC, with improved characteristics in mechanics, shaping, and biodegradability, compared to our previous study. To address this issue, this study prepared a 3D porous polycaprolactone (PCL)-hydroxyapatite (HA) scaffold combined with MC (Group A), while the control group (Group B) utilized a bone marrow stem cell seeded PCL-HA scaffold. The results of in vitro cultures and in vivo implantation demonstrated that although an initial obstruction of nutrient exchange caused by large amounts of fibrin and erythrocytes led to a decrease in the ratio of live cells in Group A, these scaffolds also showed significant improvements in cell adhesion, proliferation, and chondrogenic differentiation with porous recanalization in the later culture, compared to Group B. After 4 weeks of in vivo implantation, Group A scaffolds have a superior performance in DNA content, Sox9 and RunX2 expression, cartilage lacuna-like cell and ECM accumulation, when compared to Group B. Furthermore, Group A scaffold size and mechanics were stable during in vitro and in vivo experiments, unlike the scaffolds in our previous study. Our results suggest that the combination with MC proved to be a highly efficient, reliable, and simple new method that improves the biological performance of 3D PCL-HA scaffold. The MC-PCL-HA scaffold is a candidate for future cartilage regeneration studies. PMID:25530453

  12. Biomimetic scaffolds based on hydroxyapatite nanorod/poly(D,L) lactic acid with their corresponding apatite-forming capability and biocompatibility for bone-tissue engineering.

    PubMed

    Nga, Nguyen Kim; Hoai, Tran Thanh; Viet, Pham Hung

    2015-04-01

    This study presents a facile synthesis of biomimetic hydroxyapatite nanorod/poly(D,L) lactic acid (HAp/PDLLA) scaffolds with the use of solvent casting combined with a salt-leaching technique for bone-tissue engineering. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy were used to observe the morphologies, pore structures of synthesized scaffolds, interactions between hydroxyapatite nanorods and poly(D,L) lactic acid, as well as the compositions of the scaffolds, respectively. Porosity of the scaffolds was determined using the liquid substitution method. Moreover, the apatite-forming capability of the scaffolds was evaluated through simulated body fluid (SBF) incubation tests, whereas the viability, attachment, and distribution of human osteoblast cells (MG 63 cell line) on the scaffolds were determined through alamarBlue assay and confocal laser microscopy after nuclear staining with 4',6-diamidino-2-phenylindole and actin filaments of a cytoskeleton with Oregon Green 488 phalloidin. Results showed that hydroxyapatite nanorod/poly(D,L) lactic acid scaffolds that mimic the structure of natural bone were successfully produced. These scaffolds possessed macropore networks with high porosity (80-84%) and mean pore sizes ranging 117-183 μm. These scaffolds demonstrated excellent apatite-forming capabilities. The rapid formation of bone-like apatites with flower-like morphology was observed after 7 days of incubation in SBFs. The scaffolds that had a high percentage (30 wt.%) of hydroxyapatite demonstrated better cell adhesion, proliferation, and distribution than those with low percentages of hydroxyapatite as the days of culture increased. This work presented an efficient route for developing biomimetic composite scaffolds, which have potential applications in bone-tissue engineering.

  13. Biomimetic scaffolds based on hydroxyapatite nanorod/poly(D,L) lactic acid with their corresponding apatite-forming capability and biocompatibility for bone-tissue engineering.

    PubMed

    Nga, Nguyen Kim; Hoai, Tran Thanh; Viet, Pham Hung

    2015-04-01

    This study presents a facile synthesis of biomimetic hydroxyapatite nanorod/poly(D,L) lactic acid (HAp/PDLLA) scaffolds with the use of solvent casting combined with a salt-leaching technique for bone-tissue engineering. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy were used to observe the morphologies, pore structures of synthesized scaffolds, interactions between hydroxyapatite nanorods and poly(D,L) lactic acid, as well as the compositions of the scaffolds, respectively. Porosity of the scaffolds was determined using the liquid substitution method. Moreover, the apatite-forming capability of the scaffolds was evaluated through simulated body fluid (SBF) incubation tests, whereas the viability, attachment, and distribution of human osteoblast cells (MG 63 cell line) on the scaffolds were determined through alamarBlue assay and confocal laser microscopy after nuclear staining with 4',6-diamidino-2-phenylindole and actin filaments of a cytoskeleton with Oregon Green 488 phalloidin. Results showed that hydroxyapatite nanorod/poly(D,L) lactic acid scaffolds that mimic the structure of natural bone were successfully produced. These scaffolds possessed macropore networks with high porosity (80-84%) and mean pore sizes ranging 117-183 μm. These scaffolds demonstrated excellent apatite-forming capabilities. The rapid formation of bone-like apatites with flower-like morphology was observed after 7 days of incubation in SBFs. The scaffolds that had a high percentage (30 wt.%) of hydroxyapatite demonstrated better cell adhesion, proliferation, and distribution than those with low percentages of hydroxyapatite as the days of culture increased. This work presented an efficient route for developing biomimetic composite scaffolds, which have potential applications in bone-tissue engineering. PMID:25791418

  14. Preparation and evaluation of an Arg-Gly-Asp-modified chitosan/hydroxyapatite scaffold for application in bone tissue engineering

    PubMed Central

    CHEN, LIN; LI, BAOLIN; XIAO, XIAO; MENG, QINGGANG; LI, WEI; YU, QIAN; BI, JIAQI; CHENG, YONG; QU, ZHIWEI

    2015-01-01

    Bone tissue engineering has become a promising method for the repair of bone defects, and the production of a scaffold with high cell affinity and osseointegrative properties is crucial for successful bone substitute. Chitosan (CS)/hydroxyapatite (HA) composite was prepared by in situ compositing combined with lyophilization, and further modified by arginine-glycine-aspartic acid (RGD) via physical adsorption. In order to evaluate the cell adhesion rate, viability, morphology, and alkaline phosphatase (ALP) activity, the RGD-CS/HA scaffold was seeded with bone marrow stromal cells (BMSCs). The osseointegrative properties of the RGD-CS/HA scaffold were evaluated by in vivo heterotopic ossification and in vivo bone defect repair. After 4 h culture with the RGD-CS/HA scaffold, the adhesion rate of the BMSCs was 80.7%. After 3 days, BMSCs were fusiform in shape and evenly distributed on the RGD-CS/HA scaffold. Formation of extracellular matrix and numerous cell-cell interactions were observed after 48 h of culture, with an ALP content of 0.006±0.0008 U/l/ng. Furthermore, the osseointegrative ability and biomechanical properties of the RGD-CS/HA scaffold were comparable to that of normal bone tissue. The biocompatibility, cytocompatibility, histocompatibility and osseointegrative properties of the RGD-CS/HA scaffold support its use in bone tissue engineering applications. PMID:26459053

  15. Ectopic osteogenesis and angiogenesis regulated by porous architecture of hydroxyapatite scaffolds with similar interconnecting structure in vivo

    PubMed Central

    Li, Jinyu; Zhi, Wei; Xu, Taotao; Shi, Feng; Duan, Ke; Wang, Jianxin; Mu, Yandong; Weng, Jie

    2016-01-01

    The macro-pore sizes of porous scaffold play a key role for regulating ectopic osteogenesis and angiogenesis but many researches ignored the influence of interconnection between macro-pores with different sizes. In order to accurately reveal the relationship between ectopic osteogenesis and macro-pore sizes in dorsal muscle and abdominal cavities of dogs, hydroxyapatite (HA) scaffolds with three different macro-pore sizes of 500–650, 750–900 and 1100–1250 µm were prepared via sugar spheres-leaching process, which also had similar interconnecting structure determined by keeping the d/s ratio of interconnecting window diameter to macro-pore size constant. The permeability test showed that the seepage flow of fluid through the porous scaffolds increased with the increase of macro-pore sizes. The cell growth in three scaffolds was not affected by the macro-pore sizes. The in vivo ectopic implantation results indicated that the macro-pore sizes of HA scaffolds with the similar interconnecting structure have impact not only the speed of osteogenesis and angiogenesis but also the space distribution of newly formed bone. The scaffold with macro-pore sizes of 750–900 µm exhibited much faster angiogenesis and osteogenesis, and much more uniformly distribution of new bone than those with other macro-pore sizes. This work illustrates the importance of a suitable macro-pore sizes in HA scaffolds with the similar interconnecting structure which provides the environment for ectopic osteogenesis and angiogenesis. PMID:27699059

  16. Proliferation and osteogenic differentiation of human bone marrow stromal cells on alginate-gelatine-hydroxyapatite scaffolds with anisotropic pore structure.

    PubMed

    Bernhardt, A; Despang, F; Lode, A; Demmler, A; Hanke, T; Gelinsky, M

    2009-01-01

    Porous mineralized scaffolds are required for various applications in bone engineering. In particular, tube-like pores with controlled orientation inside the scaffold may support homogeneous cell seeding as well as sufficient nutrient supply and may facilitate blood vessel ingrowth. Scaffolds with parallely orientated tube-like pores were generated by diffusion-controlled ionotropic gelation of alginate. Incorporation of hydroxyapatite (HA) during the gelation process yielded stable scaffolds with an average pore diameter of approximately 90 microm. To evaluate the potential use of alginate-gelatine-HA scaffolds for bone tissue engineering, in vitro tests with human bone marrow stromal cells (hBMSCs) were carried out. We analysed biocompatibility and cell penetration into the capillary pores by microscopic methods. hBMSCs were also cultivated on alginate-gelatine-HA scaffolds for 3 weeks in the presence and absence of osteogenic supplements. We studied proliferation and osteogenic differentiation in terms of total lactate dehydrogenase (LDH) activity, DNA content and alkaline phosphatase (ALP) activity and found a 10-14-fold increase of cell number after 2 weeks of cultivation, as well as an increase of specific ALP activity for osteogenic-induced hBMSCs. Furthermore, the expression of bone-related genes [ALP, bone sialoprotein II (BSPII)] was analysed. We found an increase of ALP as well as BSPII expression for osteogenic-induced hBMSCs on alginate-gelatin-HA scaffolds.

  17. Ectopic osteogenesis and angiogenesis regulated by porous architecture of hydroxyapatite scaffolds with similar interconnecting structure in vivo

    PubMed Central

    Li, Jinyu; Zhi, Wei; Xu, Taotao; Shi, Feng; Duan, Ke; Wang, Jianxin; Mu, Yandong; Weng, Jie

    2016-01-01

    The macro-pore sizes of porous scaffold play a key role for regulating ectopic osteogenesis and angiogenesis but many researches ignored the influence of interconnection between macro-pores with different sizes. In order to accurately reveal the relationship between ectopic osteogenesis and macro-pore sizes in dorsal muscle and abdominal cavities of dogs, hydroxyapatite (HA) scaffolds with three different macro-pore sizes of 500–650, 750–900 and 1100–1250 µm were prepared via sugar spheres-leaching process, which also had similar interconnecting structure determined by keeping the d/s ratio of interconnecting window diameter to macro-pore size constant. The permeability test showed that the seepage flow of fluid through the porous scaffolds increased with the increase of macro-pore sizes. The cell growth in three scaffolds was not affected by the macro-pore sizes. The in vivo ectopic implantation results indicated that the macro-pore sizes of HA scaffolds with the similar interconnecting structure have impact not only the speed of osteogenesis and angiogenesis but also the space distribution of newly formed bone. The scaffold with macro-pore sizes of 750–900 µm exhibited much faster angiogenesis and osteogenesis, and much more uniformly distribution of new bone than those with other macro-pore sizes. This work illustrates the importance of a suitable macro-pore sizes in HA scaffolds with the similar interconnecting structure which provides the environment for ectopic osteogenesis and angiogenesis.

  18. Enhanced Healing of Rat Calvarial Defects with MSCs Loaded on BMP-2 Releasing Chitosan/Alginate/Hydroxyapatite Scaffolds

    PubMed Central

    He, Xiaoning; Liu, Yang; Yuan, Xue; Lu, Li

    2014-01-01

    In this study, we designed a chitosan/alginate/hydroxyapatite scaffold as a carrier for recombinant BMP-2 (CAH/B2), and evaluated the release kinetics of BMP-2. We evaluated the effect of the CAH/B2 scaffold on the viability and differentiation of bone marrow mesenchymal stem cells (MSCs) by scanning electron microscopy, MTS, ALP assay, alizarin-red staining and qRT-PCR. Moreover, MSCs were seeded on scaffolds and used in a 8 mm rat calvarial defect model. New bone formation was assessed by radiology, hematoxylin and eosin staining 12 weeks postoperatively. We found the release kinetics of BMP-2 from the CAH/B2 scaffold were delayed compared with those from collagen gel, which is widely used for BMP-2 delivery. The BMP-2 released from the scaffold increased MSC differentiation and did not show any cytotoxicity. MSCs exhibited greater ALP activity as well as stronger calcium mineral deposition, and the bone-related markers Col1α, osteopontin, and osteocalcin were upregulated. Analysis of in vivo bone formation showed that the CAH/B2 scaffold induced more bone formation than other groups. This study demonstrates that CAH/B2 scaffolds might be useful for delivering osteogenic BMP-2 protein and present a promising bone regeneration strategy. PMID:25084008

  19. Adipose-derived stromal cells grown on a hydroxyapatite scaffold can support hematopoiesis in regenerated bone marrow in vivo.

    PubMed

    Ueda, Takahiro; Fujita, Atsushi; Ogawa, Rei; Itoh, Yasuhiko; Fukunaga, Yoshitaka; Shimada, Takashi; Migita, Makoto

    2014-06-01

    Osteoblastic cells are a key component of the bone marrow (BM) stem cell niche and help regulate hematopoietic stem cells (HSCs). We have previously demonstrated that adipose-derived stromal cells (ADSCs) can differentiate into both osteogenic and chondrogenic cells in vitro. The current study examined whether the anatomical architecture of the BM could be regenerated in vivo by using ADSCs cultured on a hydroxyapatite (HA) scaffold. ADSCs from GFP transgenic mice were cultured in vitro on an HA scaffold. The scaffold with the attached cells was implanted subcutaneously onto the backs of C57/BL6 (Ly5.2) recipient mice. Lineage-negative (Lin-) Ly5.1 BM cells transduced with a lentiviral vector containing the luciferase (Luc) gene were intravenously administered to the recipient mice after lethal irradiation. Eight weeks after BM transplantation, the scaffolds were removed from the first recipient mice and subcutaneously implanted into lethally irradiated second recipient mice. The biodistribution and kinetics of Luc(+) Ly5.1 cells were monitored by bioluminescence imaging and flow cytometry. Luc(+) hematopoietic cells were present in the scaffolds of the secondary implanted mice for at least 8 months. Subcutaneous injection of G-CSF resulted in wide distribution of bioluminescence signals from the original scaffolds to the whole body. Therefore, BM regenerated using ADSCs grown on an HA scaffold can support HSC populations in vivo, suggesting that a functional BM niche is reconstituted. These results may have a significant impact on the development of therapeutic strategies for various hematopoietic diseases.

  20. Preparation and evaluation of an Arg-Gly-Asp-modified chitosan/hydroxyapatite scaffold for application in bone tissue engineering.

    PubMed

    Chen, Lin; Li, Baolin; Xiao, Xiao; Meng, Qinggang; Li, Wei; Yu, Qian; Bi, Jiaqi; Cheng, Yong; Qu, Zhiwei

    2015-11-01

    Bone tissue engineering has become a promising method for the repair of bone defects, and the production of a scaffold with high cell affinity and osseointegrative properties is crucial for successful bone substitute. Chitosan (CS)/hydroxyapatite (HA) composite was prepared by in situ compositing combined with lyophilization, and further modified by arginine‑glycine‑aspartic acid (RGD) via physical adsorption. In order to evaluate the cell adhesion rate, viability, morphology, and alkaline phosphatase (ALP) activity, the RGD‑CS/HA scaffold was seeded with bone marrow stromal cells (BMSCs). The osseointegrative properties of the RGD‑CS/HA scaffold were evaluated by in vivo heterotopic ossification and in vivo bone defect repair. After 4 h culture with the RGD‑CS/HA scaffold, the adhesion rate of the BMSCs was 80.7%. After 3 days, BMSCs were fusiform in shape and evenly distributed on the RGD‑CS/HA scaffold. Formation of extracellular matrix and numerous cell‑cell interactions were observed after 48 h of culture, with an ALP content of 0.006 ± 0.0008 U/l/ng. Furthermore, the osseointegrative ability and biomechanical properties of the RGD‑CS/HA scaffold were comparable to that of normal bone tissue. The biocompatibility, cytocompatibility, histocompatibility and osseointegrative properties of the RGD‑CS/HA scaffold support its use in bone tissue engineering applications. PMID:26459053

  1. A new injectable biphasic hydrogel based on partially hydrolyzed polyacrylamide and nano hydroxyapatite, crosslinked with chromium acetate, as scaffold for cartilage regeneration

    NASA Astrophysics Data System (ADS)

    Koushki, N.; Tavassoli, H.; Katbab, A. A.; Katbab, P.; Bonakdar, S.

    2015-05-01

    Polymer scaffolds are applied in the field of tissue engineering as three dimensional structures to organize cells and present stimuli to direct generation of a desired damaged tissue. In situ gelling scaffolds have attracted great attentions, as they are structurally similar to the extra cellular matrix (ECM). In the present work, attempts have been made to design and fabricate a new injectable and crosslinkable biphasic hydrogel based on partially hydrolyzed polyacrylamide (HPAM), chromium acetate as crosslink agent and nanocrystalline hydroxyapatite (nHAp) as reinforcing and bioactive agent for repair and regeneration of damaged cartilage. The distinct characteristic of HPAM is the presence of carboxylate anion groups on its backbone which allows to engineer the structure of the hydrogel for the desired bioactivity with appropriate cells differentiation towards both soft and hard (bone) tissues. The synthesized hydrogel exhibited bifunctional behavior which was derived by its biphasic structure in which one phase was loaded with nano hydroxyapatite to provide integration capability by subchondral bones and fix the hydrogel at cartilage defect without a need for suturing. The other phase differentiates the rabbit adipogenic mesenchymal stem cells (MSCs) towards soft tissue. Rheomechanical spectrometry (RMS) was employed to study the kinetic of the gelation including induction time and rate, as well as to measure the ultimate elastic modulus of the optimum crosslinked hydrogel. Surface tension measurement was also performed to tailor the surface characteristics of the gels. In vitro culturing of the cells inside the crosslinked hydrogel revealed high viability and high differentiation of the encapsulated rabbit stem cells, providing that the chromium acetate level was kept below 0.2 wt%. Based on the obtained results, the designed and fabricated biphasic hydrogel exhibited high potential as carrier for the stem cells for cartilage tissue engineering application

  2. Effects of the mold temperature on the mechanical properties and crystallinity of hydroxyapatite whisker-reinforced polyetheretherketone scaffolds.

    PubMed

    Conrad, Timothy L; Jaekel, David J; Kurtz, Steven M; Roeder, Ryan K

    2013-05-01

    Porous and bioactive polyetheretherketone (PEEK) scaffolds have potential to replace metallic scaffolds for biologic fixation of permanent implants adjacent to trabecular bone, such as interbody spinal fusion devices. The objective of this study was to investigate the effects of the mold temperature and PEEK powder on the mechanical properties and crystallinity of hydroxyapatite (HA) whisker-reinforced PEEK scaffolds prepared using compression molding and porogen leaching. Scaffolds were prepared at mold temperatures ranging 340-390°C with a 50 or 10 μm PEEK powder, 75 vol% porosity, and 20 vol% HA whiskers. Scaffold mechanical properties were evaluated in unconfined, uniaxial compression and the PEEK matrix crystallinity was measured using specular reflectance Fourier transform infrared spectroscopy. Increased mold temperature resulted in increased compressive modulus, yield strength, and yield strain, reaching a plateau at ~370°C. HA reinforcements were observed to be segregated between PEEK particles, which inhibited PEEK particle coalescence during compression molding at temperatures less than 365°C but also ensured that bioactive HA reinforcements were exposed on scaffold strut surfaces. Increased mold temperature also resulted in decreased PEEK crystallinity, particularly for scaffolds molded at greater than 375°C. The PEEK powder size exhibited relatively minor effects on the scaffold mechanical properties and PEEK crystallinity. Therefore, the results of this study suggested that HA-reinforced PEEK scaffolds should be compression molded at 370-375°C. The apparent compressive modulus, yield strength, and yield strain for scaffolds molded at 370-375°C was 75-92 MPa, 2.0-2.2 MPa, and 2.5-3.6%, respectively, which was within the range exhibited by human vertebral trabecular bone.

  3. Structure design and fabrication of porous hydroxyapatite microspheres for cell delivery

    NASA Astrophysics Data System (ADS)

    Li, Ruijing; Chen, Kexin; Li, Geng; Han, Guoxiang; Yu, Sheng; Yao, Juming; Cai, Yurong

    2016-09-01

    Porous microspheres fabricated from bioceramics have great potential for cell delivery in injectable tissue engineering application. The size and structure of pores in the microspheres are important for the effective protection and transportation of cells. In this study, porous hydroxyapatite microspheres are fabricated through the water-in-oil emulsion method followed by a calcination treatment at the high temperature. Both self-made resorcinol-formaldehyde (RF) composite spheres and camphene are used as pore-forming agents to produce big pores corresponding to the size of RF spheres and connected channel among big pores in hydroxyapatite matrix. The properties of the microspheres are characterized using X-ray diffraction, thermogravimetry analysis, universal material machine, field emission scanning electron microscopy. Cell assays are carried out to evaluate the cellular compatibility of the microspheres. The results showed that the hydroxyapatite microspheres with controllable pore structure and high porosity could be fabricated by this method, which have better strength to resist the compressive force. The microspheres are conducive to support adhesion, proliferation and differentiation of MC3T3-E1 cells. The results indicate that the obtained porous hydroxyapatite microspheres can be a permeable microenvironment for cell delivery in injectable tissue engineering.

  4. Hydroxyapatite from fish scale for potential use as bone scaffold or regenerative material.

    PubMed

    Pon-On, Weeraphat; Suntornsaratoon, Panan; Charoenphandhu, Narattaphol; Thongbunchoo, Jirawan; Krishnamra, Nateetip; Tang, I Ming

    2016-05-01

    The present paper studies the physico-chemical, bioactivity and biological properties of hydroxyapatite (HA) which is derived from fish scale (FS) (FSHA) and compares them with those of synthesized HA (sHA) obtained by co-precipitation from chemical solution as a standard. The analysis shows that the FSHA is composed of flat-plate nanocrystal with a narrow width size of about 15-20 nm and having a range of 100 nm in length and that the calcium phosphate ratio (Ca/P) is 2.01 (Ca-rich CaP). Whereas, synthesized HA consists of sub-micron HA particle having a Ca/P ratio of 1.65. Bioactivity test shows that the FSHA forms more new apatite than does the sHA after being incubated in simulated body fluid (SBF) for 7 days. Moreover, the biocompatibility study shows a higher osteoblast like cell adhesion on the FSHA surface than on the sHA substrate after 3 days of culturing. Our results also show the shape of the osteoblast cells on the FSHA changes from being a rounded shape to being a flattened shape reflecting its spreading behavior on this surface. MTT assay and ALP analysis show significant increases in the proliferation and activity of osteoblasts over the FSHA scaffold after 5 days of culturing as compared to those covering the sHA substrates. These results confirm that the bio-materials derived from fish scale (FSHA) are biologically better than the chemically synthesized HA and have the potential for use as a bone scaffold or as regenerative materials. PMID:26952413

  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. 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

  7. Protein Adsorption on Patterned Hydroxyapatite Thin Films Fabricated by Pulsed Laser Deposition

    NASA Astrophysics Data System (ADS)

    Kusunoki, Masanobu; Kawasima, Masami; Nishikawa, Hiroaki; Morimoto, Koichi; Hayami, Takashi; Hontsu, Shigeki; Kawai, Tomoji

    2005-02-01

    Protein adsorption on hydroxyapatite (HAP) thin film was investigated before and after patterning. Hydroxyapatite thin film 100 nm thick was deposited by pulsed laser deposition. The film was patterned by photolithography and wet etching with HCl solution. Proteins (phospholyrase b, bovine serum albumin, and others) labeled with fluorescein isothiocyanate (FITC) were used as the reagent. After the HAP film was soaked in the reagent and washed with pure water, a conspicuous contrast in FITC was observed between the HAP pattern and the glass substrate (or photoresist). This behavior showed that the biocompatibility of the HAP thin film was not influenced by the patterning process. Our technique for HAP thin film is adaptable for applications involving biosensors as electronic devices and scaffolds for tissue culture.

  8. New method for the fabrication of highly osteoconductive β-1,3-glucan/HA scaffold for bone tissue engineering: Structural, mechanical, and biological characterization.

    PubMed

    Klimek, Katarzyna; Przekora, Agata; Pałka, Krzysztof; Ginalska, Grażyna

    2016-10-01

    Recent studies have shown that thermal method for β-1,3-glucan (curdlan) gelation performed at temperature above 80°C enables fabrication of biocompatible bone scaffolds. The aim of this study was to establish new method for fabrication of β-1,3-glucan/hydroxyapatite (glu/HA) scaffold using ion-exchanging dialysis for curdlan gelation that allows for the modifications of the glu/HA material with thermo-sensitive agents like growth factors or adhesive proteins. Obtained results reveal that fabricated scaffold appears to be highly osteoconductive as it is nontoxic, promotes osteoblast growth and proliferation as well as increases bone alkaline phosphatase level thereby enhancing cell differentiation. It was demonstrated that developed new method for the glu/HA scaffold fabrication allows to obtain material that not only can be modified with thermo-sensitive agents at the stage of production process but also is a promising candidate for bone tissue engineering applications to act as a framework for osteoblasts to spread and form new bone. It should be noted that dialysis method for curdlan gelation has never been used before to fabricate bone scaffold. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2528-2536, 2016.

  9. Stochastic modeling, virtual refinement and deterministic fabrication of tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Rajagopalan, Srinivasan; Robb, Richard A.

    2006-03-01

    Tissue engineering attempts to address the ever widening gap between the demand and supply of organ and tissue transplants using natural and biomimetic scaffolds. The current scaffold fabrication techniques can be broadly classified into (a) conventional, irreproducible, stochastic techniques producing biomorphic "secundam naturam" but sub optimal scaffold architecture and (b) rapidly emerging, repeatable, computer-controlled Solid Freeform Fabrication (SFF) producing, "contra naturam" scaffold architecture. This paper presents an image-based scaffold optimization strategy based on microCT images of the conventional scaffolds. This approach, attempted and perfected for the first time, synergistically exploits the orthogonal techniques to create repeatable, biomorphic scaffolds with optimal scaffold geometry. The ramifications of this image based computer assisted intervention to improve the status quo of scaffold fabrication might contribute to the previously elusive deployment of promising benchside tissue analogs to the clinical bedside.

  10. Enhancement of osteoinduction by continual simvastatin release from poly(lactic-co-glycolic acid)-hydroxyapatite-simvastatin nano-fibrous scaffold.

    PubMed

    Jiang, Liming; Sun, Haizhu; Yuan, Anliang; Zhang, Kai; Li, Daowei; Li, Chen; Shi, Ce; Li, Xiangwei; Gao, Kai; Zheng, Changyu; Yang, Bai; Sun, Hongchen

    2013-11-01

    Simvastatin is considered as a stimulator for bone formation. However, the half-life for simvastatin is generally 2 hours, which means, it is difficult to maintain biologically active simvastatin in vivo. To overcome this limitation, we created a system to slowly release simvastatin in vitro and in vivo. We constructed a poly(lactic-co-glycolic acid)/hydroxyapatite nano-fibrous scaffold to carry simvastatin. Releasing assays showed that simvastatin was released from poly(lactic-co-glycolic acid)/hydroxyapatite/simvastatin quickly within - 15 days, and small amounts continued to be released through day 56 (experiments terminated). MTT assays demonstrated that both poly(lactic-co-glycolic acid)/hydroxyapatite and poly(lactic-co-glycolic acid)/hydroxyapatite/simvastatin promoted MC3T3-E1 cell proliferation. However, Alkaline phosphatase assays showed that only poly(lactic-co-glycolic acid)/hydroxyapatite/simvastatin scaffold significantly promoted the osteogenic differentiation of MC3T3-E1 cells in vitro on day 14. To further test in vivo, we created calvaria bone defect models and implanted either poly(lactic-co-glycolic acid)/hydroxyapatite or poly(lactic-co-glycolic acid)/hydroxyapatite/simvastatin. After 4 or 8 weeks post-implantation, the results indicated that poly(lactic-co-glycolic acid)/hydroxyapatite/simvastatin scaffold induced bone formation more efficiently than poly(lactic-co-glycolic acid)/hydroxyapatite alone. Our data demonstrates that poly(lactic-co-glycolic acid)/hydroxyapatite/simvastatin has the potential to aid in healing bone defects and promoting bone regeneration in the future although we still need to optimize this complex to efficiently promote bone regeneration.

  11. The effect of an alginate carrier on bone formation in a hydroxyapatite scaffold.

    PubMed

    Coathup, Melanie J; Edwards, Thomas C; Samizadeh, Sorousheh; Lo, Wei-Jen; Blunn, Gordon W

    2016-10-01

    This study investigated the osteoconductive properties of a porous hydroxyapatite (HA) scaffold manufactured using a novel technique similar to the bread-making process, alone and in combination with an alginate polysaccharide fiber gel (HA/APFG putty) and autologous bone marrow aspirate (BMA). The hypothesis was that the HA/APFG putty would be as osteoconductive as granular HA and that the presence of BMA would further enhance bone formation in an ovine femoral condyle critical defect model. Thirty-six defects were created and either (1) porous HA granules, (2) HA/APFG putty, or (3) HA/APFG putty + BMA were implanted. After retrieval at 6 and 12 weeks, image analysis techniques were used to quantify bone apposition rates, new bone area, bone-HA scaffold contact, and implant resorption. At 6 weeks postsurgery, significantly lower bone apposition rates were observed in the HA/APFG putty group when compared to the HA (p = 0.014) and HA/APFG putty + BMA (p = 0.014) groups. At 12 weeks, significantly increased amounts of new bone formation were measured within the HA scaffold (33.56 ± 3.53%) when compared to both the HA/APFG putty (16.69 ± 2.7%; p = 0.043) and the defects containing HA/APFG putty + BMA (19.31 ± 3.8%; p = 0.043). The use of an APFG gel as a carrier for injectable CaP bone substitute materials delayed bone formation in this model compared to HA granules alone which enhanced bone formation especially within the interconnected smaller pores. Our results also showed that the addition of autologous BMA did not further enhance its osteoconductive properties. Further study is required to optimize the degradation rate of this APFG binding agent before using as a directly injectable material for repair of bone defect. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1328-1335, 2016.

  12. Effect of internal structure of collagen/hydroxyapatite scaffold on the osteogenic differentiation of mesenchymal stem cells.

    PubMed

    Chen, Guobao; Lv, Yonggang; Dong, Chanjuan; Yang, Li

    2015-01-01

    Consisting of seed cells and scaffold, regenerative medicine provides a new way for the repair and regeneration of tissue and organ. Collagen/hydroxyapatite (HA) biocomposite scaffold is highlighted due to its advantageous features of two major components of bone matrix: collagen and HA. The aim of this study is to investigate the effect of internal structure of collagen/HA scaffold on the fate of rat mesenchymal stem cells (MSCs). The internal structure of collagen/HA scaffold was characterized by micro-CT. It is found that the porosity decreased while average compressive modulus increased with the increase of collagen proportion. Within the collagen proportion of 0.35%, 0.5% and 0.7%, the porosities were 89.08%, 78.37% and 75.36%, the pore sizes were 140.6±75.5 μm, 133.9±48.4 μm and 160.7±119.6 μm, and the average compressive moduli were 6.74±1.16 kPa, 8.82±2.12 kPa and 23.61±8.06 kPa, respectively. Among these three kinds of scaffolds, MSCs on the Col 0.35/HA 22 scaffold have the highest viability and the best cell proliferation. On the contrary, the Col 0.7/HA 22 scaffold has the best ability to stimulate MSCs to differentiate into osteoblasts in a relatively short period of time. In vivo research also demonstrated that the internal structure of collagen/HA scaffold has significant effect on the cell infiltration. Therefore, precise control of the internal structure of collagen/HA scaffold can provide a more efficient carrier to the repair of bone defects.

  13. A nano-sandwich construct built with graphene nanosheets and carbon nanotubes enhances mechanical properties of hydroxyapatite-polyetheretherketone scaffolds.

    PubMed

    Feng, Pei; Peng, Shuping; Wu, Ping; Gao, Chengde; Huang, Wei; Deng, Youwen; Xiao, Tao; Shuai, Cijun

    2016-01-01

    A nano-sandwich construct was built by combining two-dimensional graphene nanosheets (GNSs) and one-dimensional carbon nanotubes (CNTs) to improve the mechanical properties of hydroxyapatite-polyetheretherketone (HAP-PEEK) scaffolds for bone tissue engineering. In this nano-sandwich construct, the long tubular CNTs penetrated the interlayers of graphene and prevented their aggregation, increasing the effective contact area between the construct and matrix. The combination of GNSs and CNTs in a weight ratio of 2:8 facilitated the dispersion of each other and provided a synergetic effect in enhancing the mechanical properties. The compressive strength and modulus of the scaffolds were increased by 63.58% and 56.54% at this time compared with those of HAP-PEEK scaffolds, respectively. The carbon-based fillers, pulling out and bridging, were also clearly observed in the matrix. Moreover, the dangling of CNTs and their entangling with GNSs further reinforced the mechanical properties. Furthermore, apatite layer formed on the scaffold surface after immersing in simulated body fluid, and the cells attached and spread well on the surface of the scaffolds and displayed good viability, proliferation, and differentiation. These evidence indicate that the HAP-PEEK scaffolds enhanced by GNSs and CNTs are a promising alternative for bone tissue engineering. PMID:27555770

  14. A nano-sandwich construct built with graphene nanosheets and carbon nanotubes enhances mechanical properties of hydroxyapatite-polyetheretherketone scaffolds.

    PubMed

    Feng, Pei; Peng, Shuping; Wu, Ping; Gao, Chengde; Huang, Wei; Deng, Youwen; Xiao, Tao; Shuai, Cijun

    2016-01-01

    A nano-sandwich construct was built by combining two-dimensional graphene nanosheets (GNSs) and one-dimensional carbon nanotubes (CNTs) to improve the mechanical properties of hydroxyapatite-polyetheretherketone (HAP-PEEK) scaffolds for bone tissue engineering. In this nano-sandwich construct, the long tubular CNTs penetrated the interlayers of graphene and prevented their aggregation, increasing the effective contact area between the construct and matrix. The combination of GNSs and CNTs in a weight ratio of 2:8 facilitated the dispersion of each other and provided a synergetic effect in enhancing the mechanical properties. The compressive strength and modulus of the scaffolds were increased by 63.58% and 56.54% at this time compared with those of HAP-PEEK scaffolds, respectively. The carbon-based fillers, pulling out and bridging, were also clearly observed in the matrix. Moreover, the dangling of CNTs and their entangling with GNSs further reinforced the mechanical properties. Furthermore, apatite layer formed on the scaffold surface after immersing in simulated body fluid, and the cells attached and spread well on the surface of the scaffolds and displayed good viability, proliferation, and differentiation. These evidence indicate that the HAP-PEEK scaffolds enhanced by GNSs and CNTs are a promising alternative for bone tissue engineering.

  15. Analyzing the hydrodynamic and crowding evolution of aqueous hydroxyapatite-gelatin networks: Digging deeper into bone scaffold design variables.

    PubMed

    Sartuqui, Javier; D' Elía, Noelia; Gravina, A Noel; Messina, Paula V

    2015-07-01

    The hydration of the polypeptide network is a determinant factor to be controlled on behalf of the design of precise functional tissue scaffolding. Here we present an exhaustive study of the hydrodynamic and crowding evolution of aqueous gelatin-hydroxyapatite systems with the aim of increasing the knowledge about the biomimesis of collagen mineralization; and how it can be manipulated for the preparation of collagenous derived frameworks with specific morphological characteristics. The solution's density and viscosity evaluation measurements in combination with spectroscopic techniques revealed that there is a progressive association of protein chain that can be influenced by the amount of hydroxyapatite nanorods. Gelatin and additives' concentration effect on the morphology of the gelatin scaffolds was investigated. Transverse and longitudinal sections of the obtained scaffolds were taken and analyzed using optical microscopy. It can be seen that the porous size and shape of gelatin assemblies can be easily adjusted by controlling the gelatin/HAp ratio in the solution used as template in agreement with our statement.

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

    PubMed

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

    2016-06-01

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

  17. Evaluate the growth and adhesion of osteoblast cells on nanocomposite scaffold of hydroxyapatite/titania coated with poly hydroxybutyrate

    PubMed Central

    Pourmollaabbassi, Babak; Karbasi, Saeed; Hashemibeni, Batool

    2016-01-01

    Background: The generation of bioartificial bone tissues may help to overcome the problems related to donor site morbidity and size limitations. Materials and Methods: In this paper, hydroxyapatite (HA) powder was made out of bovine bone by thermal analysis at 900°C and first, and then, porous HA (50 weight percentage) was produced by polyurethane sponge replication method. In order to improve the scaffold mechanical properties, they have been coated with poly hydroxybutyrate. In terms of phase studies, morphology, and specifying agent groups, the specific characterization devices such as X-ray diffraction and Fourier transform infrared, were employed. To compare the behavior of cellular scaffolds, they were divided into four groups of scaffolds. The osteoblast cells were cultured. To perform phase studies, analysis of Methylthiazole tetrazolium (MTT) and Trypan blue were carried out for the viability and attachment on the surface of the scaffold, and the specification of Scanning electron microscopy was employed for the morphology of the cells. Results: The results of MTT analysis performed on four groups of scaffolds have shown that Titanium oxide (Tio2) had no effect on cell growth alone and HA was the main factor of growth and cell osteoblast adhesion on the scaffold. Moreover, the results showed that the use of coating with poly-3-hydroxybutyrate saved the factors and placed the osteoblasts within the pore. Since the main part of bone consists of HA, the TiO2 accelerates the formation of apatite crystals at the scaffold surface which is the evidence for bone tissue regeneration. Conclusions: It is likely that the relation between HA and TiO2 leads to an increase in osteoblast adhesion and growth of cells on the scaffold surface. PMID:27761431

  18. Automated quantitative characterization of alginate/hydroxyapatite bone tissue engineering scaffolds by means of micro-CT image analysis.

    PubMed

    Brun, Francesco; Turco, Gianluca; Accardo, Agostino; Paoletti, Sergio

    2011-12-01

    Accurate image acquisition techniques and analysis protocols for a reliable characterization of tissue engineering scaffolds are yet to be well defined. To this aim, the most promising imaging technique seems to be the X-ray computed microtomography (μ-CT). However critical issues of the analysis process deal with the representativeness of the selected Volume of Interest (VOI) and, most significantly, its segmentation. This article presents an image analysis protocol that computes a set of quantitative descriptors suitable for characterizing the morphology and the micro-architecture of alginate/hydroxyapatite bone tissue engineering scaffolds. Considering different VOIs extracted from different μ-CT datasets, an automated segmentation technique is suggested and compared against a manual segmentation. Variable sizes of VOIs are also considered in order to assess their representativeness. The resulting image analysis protocol is reproducible, parameter-free and it automatically provides accurate quantitative information in addition to the simple qualitative observation of the acquired images.

  19. Fabrication of three-dimensional nano, micro and micro/nano scaffolds of porous poly(lactic acid) by electrospinning and comparison of cell infiltration by Z-stacking/three-dimensional projection technique.

    PubMed

    Shalumon, K T; Chennazhi, K P; Tamura, H; Kawahara, K; Nair, S V; Jayakumar, R

    2012-03-01

    The use of electrospun extracellular matrix (ECM)-mimicking nanofibrous scaffolds for tissue engineering is limited by poor cellular infiltration. The authors hypothesised that cell penetration could be enhanced in scaffolds by using a hierarchical structure where nano fibres are combined with micron-scale fibres while preserving the overall scaffold architecture. To assess this, we fabricated electrospun porous poly(lactic acid) (PLA) scaffolds having nanoscale, microscale and combined micro/nano architecture and evaluated the structural characteristics and biological response in detail. Although the bioactivity was intermediate to that for nanofibre and microfibre scaffold, a unique result of this study was that the micro/nano combined fibrous scaffold showed improved cell infiltration and distribution than the nanofibrous scaffold. Although the cells were found to be lining the scaffold periphery in the case of nanofibrous scaffold, micro/nano scaffolds had cells dispersed throughout the scaffold. Further, as expected, the addition of nanoparticles of hydroxyapatite (nHAp) improved the bioactivity, although it did not play a significant role in cell penetration. Thus, this strategy of creating a three-dimensional (3D) micro/nano architecture that would increase the porosity of the fibrous scaffold and thereby improving the cell penetration, can be utilised for the generation of functional tissue engineered constructs in vitro.

  20. Evaluation of bone regeneration, angiogenesis, and hydroxyapatite conversion in critical-sized rat calvarial defects implanted with bioactive glass scaffolds.

    PubMed

    Bi, Lianxiang; Jung, Steve; Day, Delbert; Neidig, Katie; Dusevich, Vladimir; Eick, David; Bonewald, Lynda

    2012-12-01

    Bioactive glasses are biocompatible materials that convert to hydroxyapatite in vivo, and potentially support bone formation, but have mainly been available in particulate and not scaffold form. In this study, borosilicate and borate bioactive glass scaffolds were evaluated in critical-sized rat calvarial defects. Twelve-week-old rats were implanted with 45S5 silicate glass particles and scaffolds of 1393 silicate, 1393B1 borosilicate, and 1393B3 borate glass. After 12 weeks, the defects were harvested, stained with hematoxylin and eosin to evaluate bone regeneration, Periodic Acid Schiff to quantitate blood vessel area, and von Kossa and backscatter SEM to estimate newly mineralized bone and hydroxyapatite conversion of bioactive glasses. The amount of new bone was 12.4% for 45S5, 8.5% for 1393, 9.7% for 1393B1, and 14.9% for 1393B3 (*p = 0.04; cf. 1393 and 1393B1). Blood vessel area was significantly higher (p = 0.009) with 45S5 (3.8%), with no differences among 1393 (2.0%), 1393B1 (2.4%), or 1393B3 (2.2%). Percent von Kossa-positive area was 18.7% for 45S5, 25.4% for 1393, 29.5% for 1393B1, and 30.1% for 1393B3, significantly higher (p = 0.014) in 1393B1 and 1393B3 glasses than in 45S5. 45S5 and 1393B3 converted completely to HA in vivo. The 1393B3 glass provided greater bone formation and may be more promising for bone defect repair due to its capacity to be molded into scaffolds. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3267-3275, 2012.

  1. Fabrication of long-acting drug release property of hierarchical porous bioglasses/polylactic acid fibre scaffolds for bone tissue engineering.

    PubMed

    Wang, Dan; Lin, Huiming; Jiang, Jingjie; Jin, Qumei; Li, Lei; Dong, Yan; Qu, Fengyu

    2015-04-01

    Hierarchical porous fibre scaffolds with mesoporous bioglasses (MBGs) and polylactic acid (PLA) were successfully fabricated by the electrospinning method. These compound scaffolds possess macropores with sizes of about 100 nm because of the solvent evaporation from the fibre and the mesoporous structure ( ∼4.0 nm) originated from MBGs. The biomineralisation ability was investigated in simulated body fluid. The fibre structure is beneficial for inducing the growth of hydroxyapatite. In addition, compared with pure MBGs, the materials (MP-1 and MP-2) exhibit a long-acting drug release process up to 140 h and the drug release process corresponds with the Fickian diffusion mechanism. With the special fibre morphology and the hierarchical porous structure, the MBGs/PLA fibre scaffolds are expected to have potential application for bone tissue repair and regeneration.

  2. Micromechanical finite-element modeling and experimental characterization of the compressive mechanical properties of polycaprolactone-hydroxyapatite composite scaffolds prepared by selective laser sintering for bone tissue engineering.

    PubMed

    Eshraghi, Shaun; Das, Suman

    2012-08-01

    Bioresorbable scaffolds with mechanical properties suitable for bone tissue engineering were fabricated from polycaprolactone (PCL) and hydroxyapatite (HA) by selective laser sintering (SLS) and modeled by finite-element analysis (FEA). Both solid gage parts and scaffolds having 1-D, 2-D and 3-D orthogonal, periodic porous architectures were made with 0, 10, 20 and 30 vol.% HA. PCL:HA scaffolds manufactured by SLS had nearly full density (99%) in the designed solid regions and had excellent geometric and dimensional control. Through optimization of the SLS process, the compressive moduli for our solid gage parts and scaffolds are the highest reported in the literature for additive manufacturing. The compressive moduli of solid gage parts were 299.3, 311.2, 415.5 and 498.3 MPa for PCL:HA loading at 100:0, 90:10, 80:20 and 70:30, respectively. The compressive effective stiffness tended to increase as the loading of HA was increased and the designed porosity was lowered. In the case of the most 3-D porous scaffold, the compressive modulus more than doubled from 14.9 to 36.2 MPa when changing the material from 100:0 to 70:30 PCL:HA. A micromechanical FEA model was developed to investigate the reinforcement effect of HA loading on the compressive modulus of the bulk material. Using a first-principles based approach, the random distribution of HA particles in a solidified PCL matrix was modeled for any HA loading to predict the bulk mechanical properties of the composites. The bulk mechanical properties were also used for FEA of the scaffold geometries. The results of the FEA were found to be in good agreement with experimental mechanical testing. The development of patient- and site-specific composite tissue-engineering constructs with tailored properties can be seen as a direct extension of this work on computational design, a priori modeling of mechanical properties and direct digital manufacturing. PMID:22522129

  3. Polymer-ceramic spiral structured scaffolds for bone tissue engineering: effect of hydroxyapatite composition on human fetal osteoblasts.

    PubMed

    Zhang, Xiaojun; Chang, Wei; Lee, Paul; Wang, Yuhao; Yang, Min; Li, Jun; Kumbar, Sangamesh G; Yu, Xiaojun

    2014-01-01

    For successful bone tissue engineering, a scaffold needs to be osteoconductive, porous, and biodegradable, thus able to support attachment and proliferation of bone cells and guide bone formation. Recently, hydroxyapatites (HA), a major inorganic component of natural bone, and biodegrade polymers have drawn much attention as bone scaffolds. The present study was designed to investigate whether the bone regenerative properties of nano-HA/polycaprolactone (PCL) spiral scaffolds are augmented in an HA dose dependent manner, thereby establishing a suitable composition as a bone formation material. Nano-HA/PCL spiral scaffolds were prepared with different weight ratios of HA and PCL, while porosity was introduced by a modified salt leaching technique. Human fetal osteoblasts (hFOBs) were cultured on the nano-HA/PCL spiral scaffolds up to 14 days. Cellular responses in terms of cell adhesion, viability, proliferation, differentiation, and the expression of bone-related genes were investigated. These scaffolds supported hFOBs adhesion, viability and proliferation. Cell proliferation trend was quite similar on polymer-ceramic and neat polymer spiral scaffolds on days 1, 7, and 14. However, the significantly increased amount of alkaline phosphatase (ALP) activity and mineralized matrix synthesis was evident on the nano-HA/PCL spiral scaffolds. The HA composition in the scaffolds showed a significant effect on ALP and mineralization. Bone phenotypic markers such as bone sialoprotein (BSP), osteonectin (ON), osteocalcin (OC), and type I collagen (Col-1) were semi-quantitatively estimated by reverse transcriptase polymerase chain reaction analysis. All of these results suggested the osteoconductive characteristics of HA/PCL nanocomposite and cell maturation were HA dose dependent. For instance, HA∶PCL = 1∶4 group showed significantly higher ALP mineralization and elevated levels of BSP, ON, OC and Col-I expression as compared other lower or higher ceramic ratios

  4. Osteogenesis and trophic factor secretion are influenced by the composition of hydroxyapatite/poly(lactide-co-glycolide) composite scaffolds.

    PubMed

    He, Jiawei; Genetos, Damian C; Leach, J Kent

    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.

  5. 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

  6. Templated repair of long bone defects in rats with bioactive spiral-wrapped electrospun amphiphilic polymer/hydroxyapatite scaffolds.

    PubMed

    Kutikov, Artem B; Skelly, Jordan D; Ayers, David C; Song, Jie

    2015-03-01

    Effective repair of critical-size long bone defects presents a significant clinical challenge. Electrospun scaffolds can be exploited to deliver protein therapeutics and progenitor cells, but their standalone application for long bone repair has not been explored. We have previously shown that electrospun composites of amphiphilic poly(d,l-lactic acid)-co-poly(ethylene glycol)-co-poly(d,l-lactic acid) (PELA) and hydroxyapatite (HA) guide the osteogenic differentiation of bone marrow stromal cells (MSCs), making these scaffolds uniquely suited for evaluating cell-based bone regeneration approaches. Here we examine whether the in vitro bioactivity of these electrospun scaffolds can be exploited for long bone defect repair, either through the participation of exogenous MSCs or through the activation of endogenous cells by a low dose of recombinant human bone morphogenetic protein-2 (rhBMP-2). In critical-size rat femoral segmental defects, spiral-wrapped electrospun HA-PELA with preseeded MSCs resulted in laminated endochondral ossification templated by the scaffold across the longitudinal span of the defect. Using GFP labeling, we confirmed that the exogenous MSCs adhered to HA-PELA survived at least 7 days postimplantation, suggesting direct participation of these exogenous cells in templated bone formation. When loaded with 500 ng of rhBMP-2, HA-PELA spirals led to more robust but less clearly templated bone formation than MSC-bearing scaffolds. Both treatment groups resulted in new bone bridging over the majority of the defect by 12 weeks. This study is the first demonstration of a standalone bioactive electrospun scaffold for templated bone formation in critical-size long bone defects.

  7. Osteogenic/Odontogenic Bioengineering with co-Administration of Simvastatin and Hydroxyapatite on Poly Caprolactone Based Nanofibrous Scaffold

    PubMed Central

    Samiei, Mohammad; Aghazadeh, Marziyeh; Alizadeh, Effat; Aslaminabadi, Naser; Davaran, Soodabeh; Shirazi, Sajjad; Ashrafi, Farhad; Salehi, Roya

    2016-01-01

    Purpose: Statin is an effective factor for promoting osteogenesis. The aim of the present study was to evaluate the effect of simvastatin (SIM) and/or HA addition on changes in osteogenesis levels by human DPSCs transferred onto three-dimensional (3D) nanofibrous Poly (ε-caprolactone) (PCL)/Poly lactic acide (PLLA) polymeric scaffolds. Methods: For this purpose, a 3D nanofibrous composite scaffold of PCL/PLLA/HA was prepared by electrospinning method. SIM was added to scaffolds during DPSCs culturing step. Cell proliferation and osteogenic activity levels were assessed by using MTT assay and Alizarin Red assay methods. In addition, the expression of genes responsible for osteogenesis, including BMP2, Osteocalcin, DSPP and RUNX2, were determined before and 2 weeks after incorporation of SIM. Results: The MTT assay showed that PCL/PLLA/HA scaffolds seeded with DPSCs has significant (p<0.05) more proliferative effect than PCL/PLLA or DMEM cultured cells, additionally SIM administration improved this result over the PCL/PLLA/HA scaffolds without SIM treatment. SEM imaging revealed improved adhesion and probably osteogenic differentiation of DPSCs on PCL/PLLA/HA nanofibers treated with SIM, moreover the alizarin red assay ensured significant (p<0.05) higher mineralization of this group. Finally, real time PCR confirmed the positive regulation (P<0.05) of the expression of osteo/odontogenesis markers BMP2, Osteocalcin, DSPP and RUNX2 genes in PLLA-PCL-HA (0.1)-SIM group. Conclusion: As a result, addition of simvastatin with incorporation of hydroxyapatite in PCL-PLLA scaffolds might increase the expression of osteogenesis markers in the DPSCs, with a possible increase in cell differentiation and bone formation. PMID:27766219

  8. Collagen/hydroxyapatite scaffold enriched with polycaprolactone nanofibers, thrombocyte-rich solution and mesenchymal stem cells promotes regeneration in large bone defect in vivo.

    PubMed

    Prosecká, E; Rampichová, M; Litvinec, A; Tonar, Z; Králíčková, M; Vojtová, L; Kochová, P; Plencner, M; Buzgo, M; Míčková, A; Jančář, J; Amler, E

    2015-02-01

    A three-dimensional scaffold of type I collagen and hydroxyapatite enriched with polycaprolactone nanofibers (Coll/HA/PCL), autologous mesenchymal stem cells (MSCs) in osteogenic media, and thrombocyte-rich solution (TRS) was an optimal implant for bone regeneration in vivo in white rabbits. Nanofibers optimized the viscoelastic properties of the Coll/HA scaffold for bone regeneration. MSCs and TRS in the composite scaffold improved bone regeneration. Three types of Coll/HA/PCL scaffold were prepared: an MSC-enriched scaffold, a TRS-enriched scaffold, and a scaffold enriched with both MSCs and TRS. These scaffolds were implanted into femoral condyle defects 6 mm in diameter and 10-mm deep. Untreated defects were used as a control. Macroscopic and histological analyses of the regenerated tissue from all groups were performed 12 weeks after implantation. The highest volume and most uniform distribution of newly formed bone occurred in defects treated with scaffolds enriched with both MSCs and TRS compared with that in defects treated with scaffolds enriched by either component alone. The modulus of elasticity in compressive testing was significantly higher in the Coll/HA/PCL scaffold than those without nanofibers. The composite Coll scaffold functionalized with PCL nanofibers and enriched with MSCs and TRS appears to be a novel treatment for bone defects.

  9. Fabrication of nano-hydroxyapatite on electrospun silk fibroin nanofiber and their effects in osteoblastic behavior.

    PubMed

    Wei, Kai; Li, Yuan; Kim, Kyu-Oh; Nakagawa, Yuya; Kim, Byoung-Suhk; Abe, Koji; Chen, Guo-Qiang; Kim, Ick-Soo

    2011-06-01

    In this study, a novel tissue engineering scaffold material of electrospun silk fibroin/nano-hydroxyapatite (nHA) biocomposite was prepared by means of an effective calcium and phosphate (Ca-P) alternate soaking method. nHA was successfully produced on regenerated silk fibroin nanofiber as a substrate within several minutes without any pretreatments. The morphologies of both nonmineralized and mineralized nanofibers were analyzed using a field-emission scanning electron microscopy (FESEM). The crystallographic phases of the nHA were analyzed using X-ray diffraction (XRD). Fourier transform infrared (FTIR) spectrophotometer and thermogravimetry analyses (TGA) were employed to determine the type of functional groups and the amount of nHA presenting in the silk/nHA biocomposite nanofibers, respectively. The osteoblastic activities of this novel nanofibrous biocomposite scaffold were also investigated by employing osteoblastic-like MC3T3-E1 cell line. The cell functionality such as alkaline phosphatase (ALP) activity was ameliorated on mineralized nanofibers. All these results indicated that this silk/nHA biocomposite scaffold material may be a promising biomaterial for bone tissue engineering. PMID:21442728

  10. Titanium-enriched hydroxyapatite-gelatin scaffolds with osteogenically differentiated progenitor cell aggregates for calvaria bone regeneration.

    PubMed

    Ferreira, João R; Padilla, Ricardo; Urkasemsin, Ganokon; Yoon, Kun; Goeckner, Kelly; Hu, Wei-Shou; Ko, Ching-Chang

    2013-08-01

    Adequate bony support is the key to re-establish both function and esthetics in the craniofacial region. Autologous bone grafting has been the gold standard for regeneration of problematic large bone defects. However, poor graft availability and donor-site complications have led to alternative bone tissue-engineering approaches combining osteoinductive biomaterials and three-dimensional cell aggregates in scaffolds or constructs. The goal of the present study was to generate novel cell aggregate-loaded macroporous scaffolds combining the osteoinductive properties of titanium dioxide (TiO2) with hydroxyapatite-gelatin nanocomposites (HAP-GEL) for regeneration of craniofacial defects. Here we investigated the in vivo applicability of macroporous (TiO2)-enriched HAP-GEL scaffolds with undifferentiated and osteogenically differentiated multipotent adult progenitor cell (MAPC and OD-MAPC, respectively) aggregates for calvaria bone regeneration. The silane-coated HAP-GEL with and without TiO2 additives were polymerized and molded to produce macroporous scaffolds. Aggregates of the rat MAPC were precultured, loaded into each scaffold, and implanted to rat calvaria critical-size defects to study bone regeneration. Bone autografts were used as positive controls and a poly(lactic-co-glycolic acid) (PLGA) scaffold for comparison purposes. Preimplanted scaffolds and calvaria bone from pig were tested for ultimate compressive strength with an Instron 4411(®) and for porosity with microcomputerized tomography (μCT). Osteointegration and newly formed bone (NFB) were assessed by μCT and nondecalcified histology, and quantified by calcium fluorescence labeling. Results showed that the macroporous TiO2-HAP-GEL scaffold had a comparable strength relative to the natural calvaria bone (13.8±4.5 MPa and 24.5±8.3 MPa, respectively). Porosity was 1.52±0.8 mm and 0.64±0.4 mm for TiO2-HAP-GEL and calvaria bone, respectively. At 8 and 12 weeks postimplantation into rat

  11. Fabrication of poly(lactic-co-glycolic acid) scaffolds containing silk fibroin scaffolds for tissue engineering applications.

    PubMed

    Ju, Hyung Woo; Sheikh, Faheem A; Moon, Bo Mi; Park, Hyun Jung; Lee, Ok Joo; Kim, Jung Ho; Eun, Jang Ji; Khang, Gilson; Park, Chan Hum

    2014-08-01

    The present study deals with the fabrication of poly(lactic-co-glycolic acid) (PLGA) scaffolds modified with silk fibroin for biomedical application. The PLGA solutions were added with salt particles and pressed with high pressures; which were further subjected to salt leaching resulting in the creation of large sized pores in the PLGA scaffolds. To fill up these pores, 2%, 4%, and 8% of silk solutions were added, however, the addition created extra small sized pores. The scaffolds were characterized by various state of techniques; the scanning electronic microscopy revealed the large sized pores in the pristine scaffold can be tailored into smaller architecture by the addition of silk fibroin. The contact angle measurements confirmed the introduction of silk helped to change the hydrophobic nature of PLGA into hydrophilic, which is the main constrain for PLGA. The mechanical properties of scaffold can be easily improved by applying the higher amounts of silk into the scaffolds. The thermal gravimetric analyses and fourier transform infrared spectroscopy confirmed the presence of silk fibroin in scaffolds. The cell viability and cell attachment was checked by culturing the scaffolds with NIH 3T3 fibroblasts and chondrocytes. Furthermore, these results revealed that the introduction of silk had significant impact on the viability of fibroblast also had a good affinity for cell attachment and infiltration of human chondrocytes in scaffolds after culturing the cells for 2 and 5 weeks of time. PMID:24026912

  12. Engineered electrospun poly(caprolactone)/polycaprolactone-g-hydroxyapatite nano-fibrous scaffold promotes human fibroblasts adhesion and proliferation.

    PubMed

    Keivani, F; Shokrollahi, P; Zandi, M; Irani, S; F Shokrolahi; Khorasani, S C

    2016-11-01

    Polycaprolactone (PCL)/hydroxyapatite nano-composites are among the best candidates for tissue engineering. However, interactions between nHAp and PCL are difficult to control leading to inhomogeneous dispersion of the bio-ceramic particles. Grafting of polymer chains at high density/chain length while promotes the phase compatibility may result in reduced HAp exposed surface area and therefore, bioactivity is compromised. This issue is addressed here by grafting PCL chains onto HAp nano-particles through ring opening polymerization of ε-caprolactone (PCL-g-HAp). FTIR and TGA analysis showed that PCL (6.9wt%), was successfully grafted on the HAp. PCL/PCL-g-HAp nano-fibrous scaffold showed up to 10 and 33% enhancement in tensile strength and modulus, respectively, compared to those of PCL/HAp. The effects of HAp on the in vitro HAp formation were investigated for both the PCL/HAp and PCL/PCL-g-HAp scaffolds. Precipitation of HAp on the nano-composite scaffolds observed after 15days incubation in simulated body fluid (SBF), as confirmed by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Human fibroblasts were seeded on PCL, PCL/HAp and PCL/PCL-g-HAp scaffolds. According to MTT assay, the highest cell proliferation was recorded for PCL/PCL-g-HAp nano-composite, at all time intervals (1-21days, P<0.001). Fluorescent microscopy (of DAPI stained samples) and electron microscopy images showed that all nano-fibrous scaffolds (PCL, PCL/HAp, and PCL/PCL-g-HAp), were non-toxic against cells, while more cell adhesion, and the most uniform cell distribution observed on the PCL/PCL-g-HAp. Overall, grafting of relatively short chains of PCL on the surface of HAp nano-particles stimulates fibroblasts adhesion and proliferation on the PCL/PCL-g-HAp nano-composite. PMID:27523999

  13. Engineered electrospun poly(caprolactone)/polycaprolactone-g-hydroxyapatite nano-fibrous scaffold promotes human fibroblasts adhesion and proliferation.

    PubMed

    Keivani, F; Shokrollahi, P; Zandi, M; Irani, S; F Shokrolahi; Khorasani, S C

    2016-11-01

    Polycaprolactone (PCL)/hydroxyapatite nano-composites are among the best candidates for tissue engineering. However, interactions between nHAp and PCL are difficult to control leading to inhomogeneous dispersion of the bio-ceramic particles. Grafting of polymer chains at high density/chain length while promotes the phase compatibility may result in reduced HAp exposed surface area and therefore, bioactivity is compromised. This issue is addressed here by grafting PCL chains onto HAp nano-particles through ring opening polymerization of ε-caprolactone (PCL-g-HAp). FTIR and TGA analysis showed that PCL (6.9wt%), was successfully grafted on the HAp. PCL/PCL-g-HAp nano-fibrous scaffold showed up to 10 and 33% enhancement in tensile strength and modulus, respectively, compared to those of PCL/HAp. The effects of HAp on the in vitro HAp formation were investigated for both the PCL/HAp and PCL/PCL-g-HAp scaffolds. Precipitation of HAp on the nano-composite scaffolds observed after 15days incubation in simulated body fluid (SBF), as confirmed by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Human fibroblasts were seeded on PCL, PCL/HAp and PCL/PCL-g-HAp scaffolds. According to MTT assay, the highest cell proliferation was recorded for PCL/PCL-g-HAp nano-composite, at all time intervals (1-21days, P<0.001). Fluorescent microscopy (of DAPI stained samples) and electron microscopy images showed that all nano-fibrous scaffolds (PCL, PCL/HAp, and PCL/PCL-g-HAp), were non-toxic against cells, while more cell adhesion, and the most uniform cell distribution observed on the PCL/PCL-g-HAp. Overall, grafting of relatively short chains of PCL on the surface of HAp nano-particles stimulates fibroblasts adhesion and proliferation on the PCL/PCL-g-HAp nano-composite.

  14. Fabrication and characteristic analysis of a poly(propylene fumarate) scaffold using micro-stereolithography technology.

    PubMed

    Lee, Jin Woo; Lan, Phung Xuan; Kim, Byung; Lim, Geunbae; Cho, Dong-Woo

    2008-10-01

    Scaffold fabrication for regenerating functional human tissues has an important role in tissue engineering, and there has been much progress in research on scaffold fabrication. However, current methods are limited by the mechanical properties of existing biodegradable materials and the irregular structures that they produce. Recently, several promising biodegradable materials have been introduced, including poly(propylene fumarate) (PPF). The development of micro-stereolithography allows the fabrication of free-form 3D microstructures as designed. Since this technology requires a low-viscosity resin to fabricate fine structures, we reduced the viscosity of PPF by adding diethyl fumarate. Using our system, the curing characteristics and material properties of the resin were analyzed experimentally. Then, we fabricated waffle shape and 3D scaffolds containing several hundred regular micro pores. This method controlled the pore size, porosity, interconnectivity, and pore distribution. The results show that micro-stereolithography has big advantages over conventional fabrication methods. In addition, the ultimate strength and elastic modulus of the fabricated scaffolds were measured, and cell adhesion to the fabricated scaffold was observed by growing seeded cells on it. These results showed that the PPF/DEF scaffold is a potential bone scaffold for tissue engineering.

  15. Surface modification of polycaprolactone scaffolds fabricated via selective laser sintering for cartilage tissue engineering.

    PubMed

    Chen, Chih-Hao; Lee, Ming-Yih; Shyu, Victor Bong-Hang; Chen, Yi-Chieh; Chen, Chien-Tzung; Chen, Jyh-Ping

    2014-07-01

    Surface modified porous polycaprolactone scaffolds fabricated via rapid prototyping techniques were evaluated for cartilage tissue engineering purposes. Polycaprolactone scaffolds manufactured by selective laser sintering (SLS) were surface modified through immersion coating with either gelatin or collagen. Three groups of scaffolds were created and compared for both mechanical and biological properties. Surface modification with collagen or gelatin improved the hydrophilicity, water uptake and mechanical strength of the pristine scaffold. From microscopic observations and biochemical analysis, collagen-modified scaffold was the best for cartilage tissue engineering in terms of cell proliferation and extracellular matrix production. Chondrocytes/collagen-modified scaffold constructs were implanted subdermally in the dorsal spaces of female nude mice. Histological and immunohistochemical staining of the retrieved implants after 8 weeks revealed enhanced cartilage tissue formation. We conclude that collagen surface modification through immersion coating on SLS-manufactured scaffolds is a feasible scaffold for cartilage tissue engineering in craniofacial reconstruction. PMID:24857507

  16. Three-dimensional microstructured tissue scaffolds fabricated by two-photon laser scanning photolithography.

    PubMed

    Hsieh, Tseng Ming; Ng, Chien Wei Benjamin; Narayanan, Karthikeyan; Wan, Andrew C A; Ying, Jackie Y

    2010-10-01

    Current tissue engineering scaffolds fabricated via solvent casting and porogen leaching methods suffer from the lack of control over parameters such as interconnectivity and pore geometry, properties that are a function of the fabrication process. The progress of tissue engineering would thus benefit from the ability to design scaffolds that facilitate cell-cell interactions, and provide mass transfer characteristics necessary for good cell viability and function. In this research, we have developed two-photon laser scanning photolithography (TPLSP) for the fabrication of three-dimensional (3D) microstructured scaffolds with high resolution and fidelity. Modification of our two-photon setup allowed for a scan height of 30 mm and a scan speed of 30 mm/s, making it more amenable to scaffold fabrication. Scaffold production was adapted to computer-aided design (CAD)/computer-aided manufacturing (CAM) technology, to achieve the desired length scales from the submicron level and up. A commercially available photocurable resin that exhibited favorable ultraviolet-visible (UV-vis) transparency, cell compatibility and reproducibility in fabrication was used as the scaffold material. As a proof-of-concept, a microporous, cubic scaffold was fabricated for the purpose of hepatocyte culture. Primary hepatocytes could be uniformly seeded on these scaffolds as observed by confocal fluorescence microscopy. Albumin and urea assays demonstrated that hepatocytes cultured in the 3D scaffold maintained higher levels of liver-specific function over a period of 6 days as compared to the monolayer control. These results may be attributed to the high local concentration of soluble factors within the scaffold, which is important for maintaining the hepatocyte phenotype. Our study illustrates the potential of TPLSP as a new platform for the fabrication of designed, well-controlled, 3D microstructured tissue scaffolds.

  17. A Versatile Method for Fabricating Tissue Engineering Scaffolds with a Three-Dimensional Channel for Prevasculature Networks.

    PubMed

    Li, Shuai; Liu, Yuan-Yuan; Liu, Li-Jun; Hu, Qing-Xi

    2016-09-28

    Despite considerable advances in tissue engineering over the past two decades, solutions to some crucial problems remain elusive. Vascularization is one of the most important factors that greatly influence the function of scaffolds. Many research studies have focused on the construction of a vascular-like network with prevascularization structure. Sacrificial materials are widely used to build perfusable vascular-like architectures, but most of these fabricated scaffolds only have a 2D plane-connected network. The fabrication of three-dimensional perfusable branched networks remains an urgent issue. In this work, we developed a novel sacrificial molding technique for fabricating biocompatible scaffolds with a three-dimensional perfusable branched network. Here, 3D-printed poly(vinyl alcohol) (PVA) filament was used as the sacrificial material. The fused PVA was deposited on the surface of a cylinder to create the 3D branched solid network. Gelatin was used to embed the solid network. Then, the PVA mold was dissolved after curing the hydrogel. The obtained architecture shows good perfusability. Cell experiment results indicated that human umbilical vein endothelial cells (HUVECs) successfully attached to the surface of the branched channel and maintained high viability after a few days in culture. In order to prevent deformation of the channel, paraffin was coated on the surface of the printed structure, and hydroxyapatite (HA) was added to gelatin. In conclusion, we demonstrate a novel strategy toward the engineering of prevasculature thick tissues through the integration of the fused PVA filament deposit. This approach has great potential in solving the issue of three-dimensional perfusable branched networks and opens the way to clinical applications. PMID:27607243

  18. Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications.

    PubMed

    Jung, Hyun-Do; Lee, Hyun; Kim, Hyoun-Ee; Koh, Young-Hag; Song, Juha

    2015-01-01

    Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness and low bioactivity of metals. In this study, we have developed a new method towards fabricating a new type of bioactive and mechanically reliable porous metal scaffolds-densified porous Ti scaffolds. The method consists of two fabrication processes, 1) the fabrication of porous Ti scaffolds by dynamic freeze casting, and 2) coating and densification of the porous scaffolds. The dynamic freeze casting method to fabricate porous Ti scaffolds allowed the densification of porous scaffolds by minimizing the chemical contamination and structural defects. The densification process is distinctive for three reasons. First, the densification process is simple, because it requires a control of only one parameter (degree of densification). Second, it is effective, as it achieves mechanical enhancement and sustainable release of biomolecules from porous scaffolds. Third, it has broad applications, as it is also applicable to the fabrication of functionally graded porous scaffolds by spatially varied strain during densification. PMID:26709604

  19. Hybrid hydrogels self-assembled from graft copolymers containing complementary β-sheets as hydroxyapatite nucleation scaffolds

    PubMed Central

    Wu, Larisa C.; Yang, Jiyuan; Kopeček, Jindřich

    2011-01-01

    A biomimetic material that can assist bone tissue regeneration was proposed. A bone scaffold based on a hybrid hydrogel self-assembled from N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers grafted with complementary β-sheet peptides was designed. Investigation of self-assembly by circular dichroism spectroscopy suggested that hydrogel formation was triggered through association of the complementary β-sheet motifs. Congo Red and thioflavin T binding, as well as transmission electron microscopy confirmed the formation of a fibril network. Besides mimicking the natural bone extracellular matrix and maintaining preosteoblast cells viability, this hydrogel, as shown by scanning electron microscopy and Fourier transform infrared spectroscopy, provided surfaces characterized by epitaxy that favored hydroxyapatite-like crystal nucleation and growth potentially beneficial for biointegration. PMID:21549421

  20. Hybrid hydrogels self-assembled from graft copolymers containing complementary β-sheets as hydroxyapatite nucleation scaffolds.

    PubMed

    Wu, Larisa C; Yang, Jiyuan; Kopeček, Jindřich

    2011-08-01

    A biomimetic material that can assist bone tissue regeneration was proposed. A bone scaffold based on a hybrid hydrogel self-assembled from N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers grafted with complementary β-sheet peptides was designed. Investigation of self-assembly by circular dichroism spectroscopy suggested that hydrogel formation was triggered through association of the complementary β-sheet motifs. Congo Red and thioflavin T binding, as well as transmission electron microscopy confirmed the formation of a fibril network. Besides mimicking the natural bone extracellular matrix and maintaining preosteoblast cells viability, this hydrogel, as shown by scanning electron microscopy and Fourier transform infrared spectroscopy, provided surfaces characterized by epitaxy that favored hydroxyapatite-like crystal nucleation and growth potentially beneficial for biointegration. PMID:21549421

  1. In vitro mineralization of MC3T3-E1 osteoblast-like cells on collagen/nano-hydroxyapatite scaffolds coated carbon/carbon composites.

    PubMed

    Cao, Sheng; Li, Hejun; Li, Kezhi; Lu, Jinhua; Zhang, Leilei

    2016-02-01

    Collagen/nano-hydroxyapatite (collagen/nHA) scaffolds were successfully prepared on carbon/carbon composites as bioactive films using the layer-by-layer coating method. Surface characterizations of collagen/nHA scaffolds were detected by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Compressive strengths of the scaffolds were evaluated by a universal test machine. In vitro biological performances were determined using scaffolds seeded with MC3T3-E1 osteoblasts-like cells and cultured in mineralization medium for up to 21 days. In addition, cellular morphologies and several related gene expressions of MC3T3-E1 cells in the scaffolds were also evaluated. Chemical and morphological analysis showed that the scaffolds had uniform pore sizes and unified phase composition. Mechanical testing indicated that the collagen/nHA scaffolds had the highest compressive strength in 50% of strain condition when the proportion of collagen and nano-hydroxyapatite was 1:3. Cellular morphology observations and cytology tests indicated that MC3T3-E1 cells were adhered on these scaffolds and proliferated. SEM photographs and gene expressions showed that mineralized MC3T3-E1 cells and newly formed extra cellular matrix (ECM) filled up the pores of the scaffolds after the 3-week mineralization inducement. Nano-sized apatite particles were secreted from MC3T3-E1 cells and combined with the reconstructed ECM. Collectively, collagen/nHA scaffolds provided C/C composites with a biomimetic surface for cell adhesion, proliferation and mineralized extra cellular matrices formation.

  2. Biocompatibility and bone-repairing effects: comparison between porous poly-lactic-co-glycolic acid and nano-hydroxyapatite/poly(lactic acid) scaffolds.

    PubMed

    Zong, Chen; Qian, Xiaodan; Tang, Zihua; Hu, Qinghong; Chen, Jiarong; Gao, Changyou; Tang, Ruikang; Tong, Xiangmin; Wang, Jinfu

    2014-06-01

    Copolymer composite scaffolds and bioceramic/polymer composite scaffolds are two representative forms of composite scaffolds used for bone tissue engineering. Studies to compare biocompatibility and bone-repairing effects between these two scaffolds are significant for selecting or improving the scaffold for clinical application. We prepared two porous scaffolds comprising poly-lactic-acid/poly-glycolic-acid (PLGA) and poly-lactic-acid/nano-hydroxyapatite (nHAP/PLA) respectively, and examined their biocompatibility with human bone marrow-derived mesenchymal stem cells (hMSCs) through evaluating adhesion, proliferation and osteogenic differentiation potentials of hMSCs in the scaffold. Then, the PLGA scaffold with hMSCs (PM construct) and the nHAP/PLA scaffold with hMSCs (HPM construct) were transplanted into the rat calvarial defect areas to compare their effects on the bone reconstruction. The results showed that the nHAP/PLA scaffold was in favor of adhesion, matrix deposition and osteogenic differentiation of hMSCs. For in vivo transplantation, both HPM and PM constructs led to mineralization and osteogenesis in the defect area of rat. However, the area grafted with PM construct showed a better formation of mature bone than that with HPM construct. In addition, the evaluation of in vitro and in vivo degradation indicated that the degradation rate of nHAP/PLA scaffold was much lower than that of PLGA scaffold. It is inferred that the lower degradation of nHAP/PLA scaffold should result in its inferior bone reconstruction in rat calvaria. Therefore, the preparation of an ideal composite scaffold for bone tissue engineering should be taken into account of the balance between its biocompatibility, degradation rate, osteoconductivity and mechanical property.

  3. Fabrication and characterization of novel biomimetic PLLA/cellulose/hydroxyapatite nanocomposite for bone repair applications.

    PubMed

    Eftekhari, Samin; El Sawi, Ihab; Bagheri, Zahra Shaghayegh; Turcotte, Ginette; Bougherara, Habiba

    2014-06-01

    The purpose of this research is to develop and characterize a novel biomimetic nanocomposite that closely mimics the properties of real bone such as morphology, composition and mechanical characteristics. This novel porous nanocomposite is composed of cotton-sourced cellulose microcrystals, hydroxyapatite nanoparticles and poly l-lactide acid. A unique combination of commonly used fabrication procedures has been developed including pre-treatment of particles using a coupling agent. The effect of various weight ratios of the reinforcing agents was evaluated to assess their influence on the chemical, thermal, and mechanical properties of the nanocomposites. The prepared nanocomposites were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and compression testing. Our results indicated the presence of molecular interactions between all components leading to an increase of the crystallinity of the polymer from 50% to 80%. Compression test results revealed that increasing the weight ratio of microcrystalline cellulose/poly l-lactide acid and hydroxyapatite/poly l-lactide acid from 0.1 to 0.5 enhanced the compressive yield stress from 0.127 to 2.2MPa and The Young's modulus from 6.6 to 38MPa, respectively. It was found that the fabricated nanocomposites are comparable with the trabecular bone from compositional, structural, and mechanical point of view. PMID:24863207

  4. FEM modeling of the reinforcement mechanism of Hydroxyapatite in PLLA scaffolds produced by supercritical drying, for Tissue Engineering applications.

    PubMed

    Baldino, L; Naddeo, F; Cardea, S; Naddeo, A; Reverchon, E

    2015-11-01

    Scaffolds have been produced by supercritical CO2 drying of Poly-L-Lactid Acid (PLLA) gels loaded with micrometric fructose particles used as porogens. These structures show a microporous architecture generated by the voids left in the solid material by porogen leaching, while they maintain the nanostructure of the gel, consisting of a network of nanofilaments. These scaffolds have also been loaded with Hydroxyapatite (HA) nanoparticles, from 10 to 50% w/w with respect to the polymer, to improve the mechanical properties of the PLLA structure. Based on miscroscopic and mechanical considerations, we propose a parametric Finite Element Method (FEM) model of PLLA-HA composites that describes the microporous structure as a close-packing of equal spheres and the nanoscale structure as a space frame of isotropic curved fibers. The effect of HA on the mechanical properties of the scaffolds has been modeled on the basis of SEM images and by taking into consideration the formation of concentric cylinders of HA nanoparticles around PLLA nanofibers. Modeling analysis confirms that mechanical properties of these scaffolds depend on nanofibrous network connections and that bending is the major factor causing deformation of the network. The FEM model also takes into account the formation of HA multi-layer coating on some areas in the nanofiber network and its increase in thickness with HA percentage. The Young modulus tends to a plateau for HA percentages larger than 30% w/w and when the coverage of the nanofibers produced by HA nanoparticles reaches a loaded surface index of 0.14 in the FEM model.

  5. Fabrication of Porous α-TCP/Gellan Gum Scaffold for Bone Tissue Engineering.

    PubMed

    Wen, Jian; Kim, Ill Yong; Kikuta, Koichi; Ohtsuki, Chikara

    2016-03-01

    α-tricalcium phosphate (α-TCP, α-Ca3(PO4)2) receives great attention for bone repairing due to its biodegradability and capability of transformation to human bone's main inorganic components, hydroxyapatite (HAp). α-TCP porous scaffold is easily procurable by sintering of the low-temperature polymorph of TCP, β-TCR Still, porous body of α-TCP is too brittle to being handled and shaped, limiting its clinical application as implant materials. To improve mechanical properties of α-TCP porous scaffold, the present study focused on coating of a type of polysaccharides on α-TCP scaffolds. Gellan gum was chosen as the polysaccharide for coating because of its biodegradability as well as the potential acting as substrate for HAp deposition during hydration of α-TCP after exposure to body fluid. After coating of gellan gum on α-TCP scaffolds with porosity of 75 vol%, the compressive strength increased from 0.45 MPa to around 2.00 MPa. Among the coated scaffold, the maximum compressive strength, 3.97 MPa, was obtained on the scaffold with porosity of 63 vol%. Improvement of mechanical properties of α-TCP/gellan gum composites was achieved to show easy handling performance for a bone substitute for tissue repairing. The dissolving rate of the coated scaffolds was also controlled by adjusting the concentration of GG solutions. PMID:27455764

  6. Fabrication of functional PLGA-based electrospun scaffolds and their applications in biomedical engineering.

    PubMed

    Zhao, Wen; Li, Jiaojiao; Jin, Kaixiang; Liu, Wenlong; Qiu, Xuefeng; Li, Chenrui

    2016-02-01

    Electrospun PLGA-based scaffolds have been applied extensively in biomedical engineering, such as tissue engineering and drug delivery system. Due to lack of the recognition sites on cells, hydropholicity and single-function, the applications of PLGA fibrous scaffolds are limited. In order to tackle these issues, many works have been done to obtain functional PLGA-based scaffolds, including surface modifications, the fabrication of PLGA-based composite scaffolds and drug-loaded scaffolds. The functional PLGA-based scaffolds have significantly improved cell adhesion, attachment and proliferation. Moreover, the current study has summarized the applications of functional PLGA-based scaffolds in wound dressing, vascular and bone tissue engineering area as well as drug delivery system.

  7. Fabrication of functional PLGA-based electrospun scaffolds and their applications in biomedical engineering.

    PubMed

    Zhao, Wen; Li, Jiaojiao; Jin, Kaixiang; Liu, Wenlong; Qiu, Xuefeng; Li, Chenrui

    2016-02-01

    Electrospun PLGA-based scaffolds have been applied extensively in biomedical engineering, such as tissue engineering and drug delivery system. Due to lack of the recognition sites on cells, hydropholicity and single-function, the applications of PLGA fibrous scaffolds are limited. In order to tackle these issues, many works have been done to obtain functional PLGA-based scaffolds, including surface modifications, the fabrication of PLGA-based composite scaffolds and drug-loaded scaffolds. The functional PLGA-based scaffolds have significantly improved cell adhesion, attachment and proliferation. Moreover, the current study has summarized the applications of functional PLGA-based scaffolds in wound dressing, vascular and bone tissue engineering area as well as drug delivery system. PMID:26652474

  8. Fabrication and Mechanical Characterization of Hydrogel Infused Network Silk Scaffolds

    PubMed Central

    Kundanati, Lakshminath; Singh, Saket K.; Mandal, Biman B.; Murthy, Tejas G.; Gundiah, Namrata; Pugno, Nicola M.

    2016-01-01

    Development and characterization of porous scaffolds for tissue engineering and regenerative medicine is of great importance. In recent times, silk scaffolds were developed and successfully tested in tissue engineering and drug release applications. We developed a novel composite scaffold by mechanical infusion of silk hydrogel matrix into a highly porous network silk scaffold. The mechanical behaviour of these scaffolds was thoroughly examined for their possible use in load bearing applications. Firstly, unconfined compression experiments show that the denser composite scaffolds displayed significant enhancement in the elastic modulus as compared to either of the components. This effect was examined and further explained with the help of foam mechanics principles. Secondly, results from confined compression experiments that resemble loading of cartilage in confinement, showed nonlinear material responses for all scaffolds. Finally, the confined creep experiments were performed to calculate the hydraulic permeability of the scaffolds using soil mechanics principles. Our results show that composite scaffolds with some modifications can be a potential candidate for use of cartilage like applications. We hope such approaches help in developing novel scaffolds for tissue engineering by providing an understanding of the mechanics and can further be used to develop graded scaffolds by targeted infusion in specific regions. PMID:27681725

  9. Polymeric vs hydroxyapatite-based scaffolds on dental pulp stem cell proliferation and differentiation

    PubMed Central

    Khojasteh, Arash; Motamedian, Saeed Reza; Rad, Maryam Rezai; Shahriari, Mehrnoosh Hasan; Nadjmi, Nasser

    2015-01-01

    AIM: To evaluate adhesion, proliferation and differentiation of human dental pulp stem cells (hDPSCs) on four commercially available scaffold biomaterials. METHODS: hDPSCs were isolated from human dental pulp tissues of extracted wisdom teeth and established in stem cell growth medium. hDPSCs at passage 3-5 were seeded on four commercially available scaffold biomaterials, SureOss (Allograft), Cerabone (Xenograft), PLLA (Synthetic), and OSTEON II Collagen (Composite), for 7 and 14 d in osteogenic medium. Cell adhesion and morphology to the scaffolds were evaluated by scanning electron microscopy (SEM). Cell proliferation and differentiation into osteogenic lineage were evaluated using DNA counting and alkaline phosphatase (ALP) activity assay, respectively. RESULTS: All scaffold biomaterials except SureOss (Allograft) supported hDPSC adhesion, proliferation and differentiation. hDPSCs seeded on PLLA (Synthetic) scaffold showed the highest cell proliferation and attachment as indicated with both SEM and DNA counting assay. Evaluating the osteogenic differentiation capability of hDPSCs on different scaffold biomaterials with ALP activity assay showed high level of ALP activity on cells cultured on PLLA (Synthetic) and OSTEON II Collagen (Composite) scaffolds. SEM micrographs also showed that in the presence of Cerabone (Xenograft) and OSTEON II Collagen (Composite) scaffolds, the hDPSCs demonstrated the fibroblastic phenotype with several cytoplasmic extension, while the cells on PLLA scaffold showed the osteoblastic-like morphology, round-like shape. CONCLUSION: PLLA scaffold supports adhesion, proliferation and osteogenic differentiation of hDPSCs. Hence, it may be useful in combination with hDPSCs for cell-based reconstructive therapy. PMID:26640621

  10. Preparation, in vitro degradability, cytotoxicity, and in vivo biocompatibility of porous hydroxyapatite whisker-reinforced poly(L-lactide) biocomposite scaffolds.

    PubMed

    Xie, Lu; Yu, Haiyang; Yang, Weizhong; Zhu, Zhuoli; Yue, Li

    2016-01-01

    Biodegradable and bioactive scaffolds with interconnected macroporous structures, suitable biodegradability, adequate mechanical property, and excellent biocompatibility have drawn increasing attention in bone tissue engineering. Hence, in this work, porous hydroxyapatite whisker-reinforced poly(L-lactide) (HA-w/PLLA) composite scaffolds with different ratios of HA and PLLA were successfully developed through compression molding and particle leaching. The microstructure, in vitro mineralization, cytocompatibility, hemocompatibility, and in vivo biocompatibility of the porous HA-w/PLLA were investigated for the first time. The SEM results revealed that these HA-w/PLLA scaffolds possessed interconnected pore structures. Compared with porous HA powder-reinforced PLLA (HA-p/PLLA) scaffolds, HA-w/PLLA scaffolds exhibited better mechanical property and in vitro bioactivity, as more formation of bone-like apatite layers were induced on these scaffolds after mineralization in SBF. Importantly, in vitro cytotoxicity displayed that porous HA-w/PLLA scaffold with HA/PLLA ratio of 1:1 (HA-w1/PLLA1) produced no deleterious effect on human mesenchymal stem cells (hMSCs), and cells performed elevated cell proliferation, indicating a good cytocompatibility. Simultaneously, well-behaved hemocompatibility and favorable in vivo biocompatibility determined from acute toxicity test and histological evaluation were also found in the porous HA-w1/PLLA1 scaffold. These findings may provide new prospects for utilizing the porous HA whisker-based biodegradable scaffolds in bone repair, replacement, and augmentation applications.

  11. Biocompatibility and biomechanical characteristics of loofah based scaffolds combined with hydroxyapatite, cellulose, poly-l-lactic acid with chondrocyte-like cells.

    PubMed

    Cecen, Berivan; Kozaci, Leyla Didem; Yuksel, Mithat; Ustun, Ozcan; Ergur, Bekir Ugur; Havitcioglu, Hasan

    2016-12-01

    The current study reports the biocompatibility and biomechanical characteristics of loofah-based scaffolds combined with hydroxyapatite (HA), cellulose, poly-l-lactic acid (PLLA) with chondrocytes-like cells. Scanning electron microscope (SEM) micrographs of the scaffolds showed that the addition of PLLA usually resulted in an increase in cell's attachment on scaffolds. Mechanical and elemental analyzes were assessed using tensile test and Energy Dispersive X-ray spectrometry (EDS), respectively. In summary, we showed that the loofah+PLLA+HA scaffolds perform significantly better than other loofah-based scaffolds employed in terms of increasing a diversity of mechanical properties including tensile strength and Young's modulus. Based on the analysis of the differential scanning calorimetry (DSC) thermograms and EDS spectrums that give an idea about the calcium phosphate (CaP) ratios, the improvement in the mechanical properties could principally be recognized to the strong interaction formed between loofah, PLLA and HA. The viability of chondrocytes on loofah-based scaffolds was analyzed by XTT tests. However, none of the scaffolds have proved to be toxic in metabolic activity. The histological evaluation obtained by hematoxylin and eosin (H&E), Masson trichrome, toluidine blue and immunohistochemistry methods showed that cells in all scaffolds produced extracellular matrix that defined proteoglycan and type I-II collagens. The results of this study suggest that the loofah-based scaffold with desirable properties can be considered as an ideal candidate for cartilage tissue engineering applications. PMID:27612733

  12. Fabrication and in vitro characterization of bioactive glass composite scaffolds for bone regeneration.

    PubMed

    Poh, Patrina S P; Hutmacher, Dietmar W; Stevens, Molly M; Woodruff, Maria A

    2013-12-01

    Here we fabricate and characterize bioactive composite scaffolds for bone tissue engineering applications. 45S5 Bioglass® (45S5) or strontium-substituted bioactive glass (SrBG) were incorporated into polycaprolactone (PCL) and fabricated into 3D bioactive composite scaffolds utilizing additive manufacturing technology. We show that composite scaffolds (PCL/45S5 and PCL/SrBG) can be reproducibly manufactured with a scaffold morphology highly resembling that of PCL scaffolds. Additionally, micro-CT analysis reveals BG particles were homogeneously distributed throughout the scaffolds. Mechanical data suggested that PCL/45S5 and PCL/SrBG composite scaffolds have higher compressive Young's modulus compared to PCL scaffolds at similar porosity (∼75%). After 1 day in accelerated degradation conditions using 5M NaOH, PCL/SrBG, PCL/45S5 and PCL lost 48.6 ± 3.8%, 12.1 ± 1% and 1.6 ± 1% of the original mass, respectively. In vitro studies were conducted using MC3T3 cells under normal and osteogenic conditions. All scaffolds were shown to be non-cytotoxic, and supported cell attachment and proliferation. Our results also indicate that the inclusion of bioactive glass (BG) promotes precipitation of calcium phosphate on the scaffold surfaces which leads to earlier cell differentiation and matrix mineralization when compared to PCL scaffolds. However, as indicated by alkaline phosphatase activity, no significant difference in osteoblast differentiation was found between PCL/45S5 and PCL/SrBG scaffolds. These results suggest that PCL/45S5 and PCL/SrBG composite scaffolds show potential as next generation bone scaffolds.

  13. Woven silk fabric-reinforced silk nanofibrous scaffolds for regenerating load-bearing soft tissues.

    PubMed

    Han, F; Liu, S; Liu, X; Pei, Y; Bai, S; Zhao, H; Lu, Q; Ma, F; Kaplan, D L; Zhu, H

    2014-02-01

    Although three-dimensional (3-D) porous regenerated silk scaffolds with outstanding biocompatibility, biodegradability and low inflammatory reactions have promising application in different tissue regeneration, the mechanical properties of regenerated scaffolds, especially suture retention strength, must be further improved to satisfy the requirements of clinical applications. This study presents woven silk fabric-reinforced silk nanofibrous scaffolds aimed at dermal tissue engineering. To improve the mechanical properties, silk scaffolds prepared by lyophilization were reinforced with degummed woven silk fabrics. The ultimate tensile strength, elongation at break and suture retention strength of the scaffolds were significantly improved, providing suitable mechanical properties strong enough for clinical applications. The stiffness and degradation behaviors were then further regulated by different after-treatment processes, making the scaffolds more suitable for dermal tissue regeneration. The in vitro cell culture results indicated that these scaffolds maintained their excellent biocompatibility after being reinforced with woven silk fabrics. Without sacrifice of porous structure and biocompatibility, the fabric-reinforced scaffolds with better mechanical properties could facilitate future clinical applications of silk as matrices in skin repair. PMID:24090985

  14. Polycaprolactone scaffolds fabricated with an advanced electrohydrodynamic direct-printing method for bone tissue regeneration.

    PubMed

    Ahn, Seung Hyun; Lee, Hyeong Jin; Kim, Geun Hyung

    2011-12-12

    Electrohydrodynamic (EHD) direct writing has been used in diverse microelectromechanical systems and various supplemental methods for biotechnology and electronics. In this work, we expanded the use of EHD-induced direct writing to fabricate 3D biomedical scaffolds designed as porous structures for bone tissue engineering. To prepare the scaffolds, we modified a grounded target used in conventional EHD direct printing using a poly(ethylene oxide) solution bath, elastically cushioning the plotted struts to prevent crumbling. The fabricated scaffolds were assessed for not only physical properties including surface roughness and water uptake ability but also biological capabilities by culturing osteoblast-like cells (MG63) for the EHD-plotted polycaprolactone (PCL) scaffold. The EHD-scaffolds showed significantly roughened surface and enhanced water-absorption ability (400% increase) compared with the pure rapid-prototyped PCL. The results of cell viability, alkaline phosphatase activity, and mineralization analyses showed significantly enhanced biological properties of the scaffold (20 times the cell viability and 6 times the mineralization) compared with the scaffolds fabricated using RP technology. Because of the results, the modified EHD direct-writing process can be a promising method for fabricating 3D biomedical scaffolds in tissue engineering.

  15. 3D printing facilitated scaffold-free tissue unit fabrication.

    PubMed

    Tan, Yu; Richards, Dylan J; Trusk, Thomas C; Visconti, Richard P; Yost, Michael J; Kindy, Mark S; Drake, Christopher J; Argraves, William Scott; Markwald, Roger R; Mei, Ying

    2014-06-01

    Tissue spheroids hold great potential in tissue engineering as building blocks to assemble into functional tissues. To date, agarose molds have been extensively used to facilitate fusion process of tissue spheroids. As a molding material, agarose typically requires low temperature plates for gelation and/or heated dispenser units. Here, we proposed and developed an alginate-based, direct 3D mold-printing technology: 3D printing microdroplets of alginate solution into biocompatible, bio-inert alginate hydrogel molds for the fabrication of scaffold-free tissue engineering constructs. Specifically, we developed a 3D printing technology to deposit microdroplets of alginate solution on calcium containing substrates in a layer-by-layer fashion to prepare ring-shaped 3D hydrogel molds. Tissue spheroids composed of 50% endothelial cells and 50% smooth muscle cells were robotically placed into the 3D printed alginate molds using a 3D printer, and were found to rapidly fuse into toroid-shaped tissue units. Histological and immunofluorescence analysis indicated that the cells secreted collagen type I playing a critical role in promoting cell-cell adhesion, tissue formation and maturation.

  16. 3D Printing Facilitated Scaffold-free Tissue Unit Fabrication

    PubMed Central

    Tan, Yu; Richards, Dylan J.; Trusk, Thomas C.; Visconti, Richard P.; Yost, Michael J.; Kindy, Mark S.; Drake, Christopher J.; Argraves, William Scott; Markwald, Roger R.; Mei, Ying

    2014-01-01

    Tissue spheroids hold great potential in tissue engineering as building blocks to assemble into functional tissues. To date, agarose molds have been extensively used to facilitate fusion process of tissue spheroids. As a molding material, agarose typically requires low temperature plates for gelation and/or heated dispenser units. Here, we proposed and developed an alginate-based, direct 3D mold-printing technology: 3D printing micro-droplets of alginate solution into biocompatible, bio-inert alginate hydrogel molds for the fabrication of scaffold-free tissue engineering constructs. Specifically, we developed a 3D printing technology to deposit micro-droplets of alginate solution on calcium containing substrates in a layer-by-layer fashion to prepare ring-shaped 3D hydrogel molds. Tissue spheroids composed of 50% endothelial cells and 50% smooth muscle cells were robotically placed into the 3D printed alginate molds using a 3D printer, and were found to rapidly fuse into toroid-shaped tissue units. Histological and immunofluorescence analysis indicated that the cells secreted collagen type I playing a critical role in promoting cell-cell adhesion, tissue formation and maturation. PMID:24717646

  17. Photocurable high internal phase emulsions (HIPEs) containing hydroxyapatite for additive manufacture of tissue engineering scaffolds with multi-scale porosity.

    PubMed

    Wang, Ai-Juan; Paterson, Thomas; Owen, Robert; Sherborne, Colin; Dugan, James; Li, Jun-Ming; Claeyssens, Frederik

    2016-10-01

    Porous composites containing hydroxyapatite (HA) were templated from high internal phase emulsions (HIPEs) and were further structured using direct-write UV stereolithography to produce composite scaffolds with multi-scale porosity. FTIR, TGA and SEM analyses confirmed that HA was retained after photocuring and subsequent treatments and was incorporated within the polymerised HIPE (polyHIPE). The addition of HA particles to the polyHIPE caused changes in the mechanical properties of the material. An increase in both the Young's modulus and maximum stress at yield was observed compared with the pure polyHIPE from 1.544±0.231 to 4.614±0.775 and 0.177±0.009 to 0.267±0.034MPa, respectively. Except at very high concentrations, adding HA did not adversely cause the phase separation of the HIPE or the porous microstructure of the resulting polyHIPE. In combination with a photoinitiator, the HIPE emulsion containing HA was investigated as a photocurable resin for stereolithography-based additive manufacturing. The material was readily processable into "woodpile" structures via direct-write UV stereolithography, producing scaffolds with multi-scale porosity which may be useful for medical applications such as tissue engineering. In conclusion, HA was successfully added into polyHIPEs, producing a similar porous structure to that of the pure polyHIPE whilst improving the mechanical performance. PMID:27287098

  18. Photocurable high internal phase emulsions (HIPEs) containing hydroxyapatite for additive manufacture of tissue engineering scaffolds with multi-scale porosity.

    PubMed

    Wang, Ai-Juan; Paterson, Thomas; Owen, Robert; Sherborne, Colin; Dugan, James; Li, Jun-Ming; Claeyssens, Frederik

    2016-10-01

    Porous composites containing hydroxyapatite (HA) were templated from high internal phase emulsions (HIPEs) and were further structured using direct-write UV stereolithography to produce composite scaffolds with multi-scale porosity. FTIR, TGA and SEM analyses confirmed that HA was retained after photocuring and subsequent treatments and was incorporated within the polymerised HIPE (polyHIPE). The addition of HA particles to the polyHIPE caused changes in the mechanical properties of the material. An increase in both the Young's modulus and maximum stress at yield was observed compared with the pure polyHIPE from 1.544±0.231 to 4.614±0.775 and 0.177±0.009 to 0.267±0.034MPa, respectively. Except at very high concentrations, adding HA did not adversely cause the phase separation of the HIPE or the porous microstructure of the resulting polyHIPE. In combination with a photoinitiator, the HIPE emulsion containing HA was investigated as a photocurable resin for stereolithography-based additive manufacturing. The material was readily processable into "woodpile" structures via direct-write UV stereolithography, producing scaffolds with multi-scale porosity which may be useful for medical applications such as tissue engineering. In conclusion, HA was successfully added into polyHIPEs, producing a similar porous structure to that of the pure polyHIPE whilst improving the mechanical performance.

  19. Effect of negatively charged cellulose nanofibers on the dispersion of hydroxyapatite nanoparticles for scaffolds in bone tissue engineering.

    PubMed

    Park, Minsung; Lee, Dajung; Shin, Sungchul; Hyun, Jinho

    2015-06-01

    Nanofibrous 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)-oxidized bacterial cellulose (TOBC) was used as a dispersant of hydroxyapatite (HA) nanoparticles in aqueous solution. The surfaces of TOBC nanofibers were negatively charged after the reaction with the TEMPO/NaBr/NaClO system at pH 10 and room temperature. HA nanoparticles were simply adsorbed on the TOBC nanofibers (HA-TOBC) and dispersed well in DI water. The well-dispersed HA-TOBC colloidal solution formed a hydrogel after the addition of gelatin, followed by crosslinking with glutaraldehyde (HA-TOBC-Gel). The chemical modification of the fiber surfaces and the colloidal stability of the dispersion solution confirmed TOBC as a promising HA dispersant. Both the Young's modulus and maximum tensile stress increased as the amount of gelatin increased due to the increased crosslinking of gelatin. In addition, the well-dispersed HA produced a denser scaffold structure resulting in the increase of the Young's modulus and maximum tensile stress. The well-developed porous structures of the HA-TOBC-Gel composites were incubated with Calvarial osteoblasts. The HA-TOBC-Gel significantly improved cell proliferation as well as cell differentiation confirming the material as a potential candidate for use in bone tissue engineering scaffolds. PMID:25910635

  20. Effect of negatively charged cellulose nanofibers on the dispersion of hydroxyapatite nanoparticles for scaffolds in bone tissue engineering.

    PubMed

    Park, Minsung; Lee, Dajung; Shin, Sungchul; Hyun, Jinho

    2015-06-01

    Nanofibrous 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)-oxidized bacterial cellulose (TOBC) was used as a dispersant of hydroxyapatite (HA) nanoparticles in aqueous solution. The surfaces of TOBC nanofibers were negatively charged after the reaction with the TEMPO/NaBr/NaClO system at pH 10 and room temperature. HA nanoparticles were simply adsorbed on the TOBC nanofibers (HA-TOBC) and dispersed well in DI water. The well-dispersed HA-TOBC colloidal solution formed a hydrogel after the addition of gelatin, followed by crosslinking with glutaraldehyde (HA-TOBC-Gel). The chemical modification of the fiber surfaces and the colloidal stability of the dispersion solution confirmed TOBC as a promising HA dispersant. Both the Young's modulus and maximum tensile stress increased as the amount of gelatin increased due to the increased crosslinking of gelatin. In addition, the well-dispersed HA produced a denser scaffold structure resulting in the increase of the Young's modulus and maximum tensile stress. The well-developed porous structures of the HA-TOBC-Gel composites were incubated with Calvarial osteoblasts. The HA-TOBC-Gel significantly improved cell proliferation as well as cell differentiation confirming the material as a potential candidate for use in bone tissue engineering scaffolds.

  1. Fabrication of polylactide nanocomposite scaffolds for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Mkhabela, Vuyiswa J.; Ray, Suprakas Sinha

    2015-05-01

    Highly porous three-dimensional polylactide (PLA) scaffolds were obtained from PLA incorporated with different amounts of chitosan-modified montmorillonite (CS-MMT), through solvent casting and particulate leaching method. The processed scaffolds were tested in vitro for their possible application in bone tissue engineering. Scaffolds were characterized by Focused Ion Beam Scanning Electron Microscopy (FIB SEM), Fourier Transform Infra-Red (FTIR), and X-Ray Diffraction (XRD) to study their structure and intermolecular interactions. Bioresorbability tests in simulated body fluid (pH 7.4) were conducted to assess the response of the scaffolds in a simulated physiological condition. The FIB SEM images of the scaffolds showed a porous architecture with gradual change in morphology with increasing CS-MMT concentration. FTIR analysis revealed the presence of both PLA and CS-MMT particles on the surface of the scaffolds. XRD showed that the crystalline unit cell type was the same for all the scaffolds, and crystallinity decreased with an increase in CS-MMT concentration. The scaffolds were found to be bioresorbable, with rapid bioresorbability on the scaffolds with a high CS-MMT concentration.

  2. Fabrication of polylactide nanocomposite scaffolds for bone tissue engineering applications

    SciTech Connect

    Mkhabela, Vuyiswa J.; Ray, Suprakas Sinha

    2015-05-22

    Highly porous three-dimensional polylactide (PLA) scaffolds were obtained from PLA incorporated with different amounts of chitosan-modified montmorillonite (CS-MMT), through solvent casting and particulate leaching method. The processed scaffolds were tested in vitro for their possible application in bone tissue engineering. Scaffolds were characterized by Focused Ion Beam Scanning Electron Microscopy (FIB SEM), Fourier Transform Infra-Red (FTIR), and X-Ray Diffraction (XRD) to study their structure and intermolecular interactions. Bioresorbability tests in simulated body fluid (pH 7.4) were conducted to assess the response of the scaffolds in a simulated physiological condition. The FIB SEM images of the scaffolds showed a porous architecture with gradual change in morphology with increasing CS-MMT concentration. FTIR analysis revealed the presence of both PLA and CS-MMT particles on the surface of the scaffolds. XRD showed that the crystalline unit cell type was the same for all the scaffolds, and crystallinity decreased with an increase in CS-MMT concentration. The scaffolds were found to be bioresorbable, with rapid bioresorbability on the scaffolds with a high CS-MMT concentration.

  3. Fabrication of 3D porous SF/β-TCP hybrid scaffolds for bone tissue reconstruction.

    PubMed

    Park, Hyun Jung; Min, Kyung Dan; Lee, Min Chae; Kim, Soo Hyeon; Lee, Ok Joo; Ju, Hyung Woo; Moon, Bo Mi; Lee, Jung Min; Park, Ye Ri; Kim, Dong Wook; Jeong, Ju Yeon; Park, Chan Hum

    2016-07-01

    Bio-ceramic is a biomaterial actively studied in the field of bone tissue engineering. But, only certain ceramic materials can resolve the corrosion problem and possess the biological affinity of conventional metal biomaterials. Therefore, the recent development of composites of hybrid composites and polymers has been widely studied. In this study, we aimed to select the best scaffold of silk fibroin and β-TCP hybrid for bone tissue engineering. We fabricated three groups of scaffold such as SF (silk fibroin scaffold), GS (silk fibroin/small granule size of β-TCP scaffold) and GM (silk fibroin/medium granule size of β-TCP scaffold), and we compared the characteristics of each group. During characterization of the scaffold, we used scanning electron microscopy (SEM) and a Fourier transform infrared spectroscopy (FTIR) for structural analysis. We compared the physiological properties of the scaffold regarding the swelling ratio, water uptake and porosity. To evaluate the mechanical properties, we examined the compressive strength of the scaffold. During in vitro testing, we evaluated cell attachment and cell proliferation (CCK-8). Finally, we confirmed in vivo new bone regeneration from the implanted scaffolds using histological staining and micro-CT. From these evaluations, the fabricated scaffold demonstrated high porosity with good inter-pore connectivity, showed good biocompatibility and high compressive strength and modulus. In particular, the present study indicates that the GM scaffold using β-TCP accelerates new bone regeneration of implanted scaffolds. Accordingly, our scaffold is expected to act a useful application in the field of bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1779-1787, 2016. PMID:26999521

  4. Ectopic osteogenesis and scaffold biodegradation of nano-hydroxyapatite-chitosan in a rat model.

    PubMed

    He, Yiqun; Dong, Youhai; Cui, Fuzhai; Chen, Xujun; Lin, Rongqiang

    2015-01-01

    The bone-formation and scaffold-biodegradation processes have not been fully characterized. This study aimed to determine the osteogenic ability of nHA-CS osteo-induced bone marrow mesenchymal stem cell (BMSC) composites and to explore the relationship between bone formation and scaffold biodegradation. The nHA-CS osteo-induced BMSC composites (nHA-CS+cells group) and the nHA-CS scaffolds (nHA-CS group) were implanted into the femoral spatium intermusculare of SD rats. At 2, 4, 6, 8, and 12 weeks post-implantation, the rat femurs were scanned using computerized tomography (CT), and the CT values of the implants were measured and comparatively analyzed. The implants were then harvested and subjected to hematoxylin and eosin (HE) and Masson's trichrome staining, and the percentages of bone area, scaffold area and collagen area were compared between the two groups. The CT values of the implants were higher in the nHA-CS+cells group than the nHA-CS group at the same time points (P < 0.05). Histological analysis revealed that de novo bone and collagen formation in the pores of the scaffolds gradually increased from 2 weeks post-implantation in both groups and that the scaffold gradually degraded as bone formation proceeded. However, more de novo bone and collagen formation and scaffold degradation occurred in the nHA-CS+cells group than in the nHA-CS group at the same time points (P < 0.05). In conclusion, nHA-CS osteo-induced BMSC composites are promising bone tissue engineering substitutes, and osteo-induced BMSCs can significantly enhance the osteogenic ability and play an active role in the degradation of nHA-CS scaffolds on par with bone formation. PMID:26258851

  5. Fabrication of triple layered vascular scaffolds by combining electrospinning, braiding, and thermally induced phase separation

    NASA Astrophysics Data System (ADS)

    Mi, Hao-Yang; Jing, Xin; Yu, Emily; McNulty, Jason; Turng, Lih-Sheng

    2015-12-01

    Triple layered small diameter vascular scaffolds, which consisted of thermoplastic polyurethane (TPU) and silk, were fabricated in this study for the first time by combining electrospinning, braiding, and thermally induced phase separation methods. These novel vascular scaffolds, which possess three layers of different structures (nanofibrous inner layer, woven silk filament middle layer, and porous outer layer) have a desired toe region in the tensile test and sufficient suture retention and burst pressure for vascular graft applications. The endothelia cell culture tests showed that a cell layer could form on the inner surface of a scaffold with high cell viability. Furthermore, the cells showed favorable morphology on the scaffold.

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

    PubMed

    Zhang, Bokai; Kwok, Chi Tat

    2011-10-01

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

  7. Comparative evaluation of a biomimic collagen/hydroxyapatite/β-tricaleium phosphate scaffold in alveolar ridge preservation with Bio-Oss Collagen

    NASA Astrophysics Data System (ADS)

    Wang, Tong; Li, Qing; Zhang, Gui-feng; Zhou, Gang; Yu, Xin; Zhang, Jing; Wang, Xiu-mei; Tang, Zhi-hui

    2016-06-01

    Bone scaffolds are critical in current implant and periodontal regeneration approaches. In this study, we prepared a novel composite type-I collagen and hydroxyapatite (HA)/β-tricaleium phosphate (TCP) scaffold (CHTS) by incorporating type-I collagen and bovine calcined bone granules, prepared as a mixture of 50% HA and 50% TCP, by freeze drying. We then characterized the CHTS and determined its cytotoxic effects. Additionally, ridge preservation experiments were carried out to evaluate the clinical effects of the CHTS. The results demonstrated that the composite scaffolds had good surface morphology and no cytotoxicity. Additionally, an in vivo experiment in an animal model showed that the CHTS performed equally as well as Bio-Oss Collagen, a widely used bone graft in ridge preservation. These findings revealed that the CHTS, which contained natural constituents of bone, could be used as a scaffold for bone regeneration and clinical use.

  8. Solvent-assisted room-temperature compression molding approach to fabricate porous scaffolds for tissue engineering.

    PubMed

    Jing, Dianying; Wu, Linbo; Ding, Jiandong

    2006-09-15

    This study investigated the room-temperature compression molding/particle leaching approach to fabricate three-dimensional porous scaffolds for tissue engineering. Scaffolds with anatomical shapes (ear, joint, tube, cylinder) were made from biodegradable poly(D,L-lactide) and poly[(D,L-lactide)-co-glycolide]. The utility of this room-temperature compression approach comes from the effect of solvent assistance, but the tendency for post-molding scaffold shrinkage is a problem unique to this method and is thus examined with emphasis in this paper. Scaffold shrinkage was found to be tolerable under normal fabrication conditions with high salt contents, which is just what the preparation of highly porous scaffolds requires. Furthermore, the resultant porosities after salt leaching were measured as well as the initial scaffold shrinkages after solvent evaporation, and the relation between them was revealed by theoretical analysis and confirmed by comparison with experimental measurements. The pores were interconnected, and porosity can exceed 90%. The effects of porosity on the mechanical properties of porous scaffolds were also investigated. This convenient fabrication approach is a prospective method for the tailoring of porous scaffolds for a variety of possible applications in tissue engineering and tissue reconstruction.

  9. Magnetic Resonance Functional Nano-Hydroxyapatite Incorporated Poly(Caprolactone) Composite Scaffolds for In Situ Monitoring of Bone Tissue Regeneration by MRI

    PubMed Central

    Ganesh, Nitya; Ashokan, Anusha; Rajeshkannan, Ramiah; Chennazhi, Krishnaprasad; Koyakutty, Manzoor

    2014-01-01

    In this study, we have reported the incorporation of a multi-modal contrast agent based on hydroxyapatite nanocrystals, within a poly(caprolactone)(PCL) nanofibrous scaffold by electrospinning. The multifunctional hydroxyapatite nanoparticles (MF-nHAp) showed simultaneous contrast enhancement for three major molecular imaging techniques. In this article, the magnetic resonance (MR) contrast enhancement ability of the MF-nHAp was exploited for the purpose of potentially monitoring as well as for influencing tissue regeneration. These MF-nHAp containing PCL scaffolds were engineered in order to enhance the osteogenic potential as well as its MR functionality for their application in bone tissue engineering. The nano-composite scaffolds along with pristine PCL were evaluated physico-chemically and biologically in vitro, in the presence of human mesenchymal stem cells (hMSCs). The incorporation of 30–40 nm sized MF-nHAp within the nanofibers showed a substantial increase in scaffold strength, protein adsorption, proliferation, and osteogenic differentiation of hMSCs along with enhanced MR functionality. This preliminary study was performed to eventually exploit the MR contrast imaging capability of MF-nHAp in nanofibrous scaffolds for real-time imaging of the changes in the tissue engineered construct. PMID:24785187

  10. Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique.

    PubMed

    Ryan, Garrett E; Pandit, Abhay S; Apatsidis, Dimitrios P

    2008-09-01

    One of the main issues in orthopaedic implant design is the fabrication of scaffolds that closely mimic the biomechanical properties of the surrounding bone. This research reports on a multi-stage rapid prototyping technique that was successfully developed to produce porous titanium scaffolds with fully interconnected pore networks and reproducible porosity and pore size. The scaffolds' porous characteristics were governed by a sacrificial wax template, fabricated using a commercial 3D-printer. Powder metallurgy processes were employed to generate the titanium scaffolds by filling around the wax template with titanium slurry. In the attempt to optimise the powder metallurgy technique, variations in slurry concentration, compaction pressure and sintering temperature were investigated. By altering the wax design template, pore sizes ranging from 200 to 400 microm were achieved. Scaffolds with porosities of 66.8 +/- 3.6% revealed compression strengths of 104.4+/-22.5 MPa in the axial direction and 23.5 +/- 9.6 MPa in the transverse direction demonstrating their anisotropic nature. Scaffold topography was characterised using scanning electron microscopy and microcomputed tomography. Three-dimensional reconstruction enabled the main architectural parameters such as pore size, interconnecting porosity, level of anisotropy and level of structural disorder to be determined. The titanium scaffolds were compared to their intended designs, as governed by their sacrificial wax templates. Although discrepancies in architectural parameters existed between the intended and the actual scaffolds, overall the results indicate that the porous titanium scaffolds have the properties to be potentially employed in orthopaedic applications.

  11. Application of stereolithography for scaffold fabrication for tissue engineered heart valves.

    PubMed

    Sodian, Ralf; Loebe, Matthias; Hein, Andreas; Martin, David P; Hoerstrup, Simon P; Potapov, Evgenij V; Hausmann, Harald; Lueth, Tim; Hetzer, Roland

    2002-01-01

    A crucial factor in tissue engineering of heart valves is the functional and physiologic scaffold design. In our current experiment, we describe a new fabrication technique for heart valve scaffolds, derived from x-ray computed tomography data linked to the rapid prototyping technique of stereolithography. To recreate the complex anatomic structure of a human pulmonary and aortic homograft, we have used stereolithographic models derived from x-ray computed tomography and specific software (CP, Aachen, Germany). These stereolithographic models were used to generate biocompatible and biodegradable heart valve scaffolds by a thermal processing technique. The scaffold forming polymer was a thermoplastic elastomer, a poly-4-hydroxybutyrate (P4HB) and a polyhydroxyoctanoate (PHOH) (Tepha, Inc., Cambridge, MA). We fabricated one human aortic root scaffold and one pulmonary heart valve scaffold. Analysis of the heart valve included functional testing in a pulsatile bioreactor under subphysiological and supraphysiological flow and pressure conditions. Using stereolithography, we were able to fabricate plastic models with accurate anatomy of a human valvular homograft. Moreover, we fabricated heart valve scaffolds with a physiologic valve design, which included the sinus of Valsalva, and that resembled our reconstructed aortic root and pulmonary valve. One advantage of P4HB and PHOH was the ability to mold a complete trileaflet heart valve scaffold from a stereolithographic model without the need for suturing. The heart valves were tested in a pulsatile bioreactor, and it was noted that the leaflets opened and closed synchronously under subphysiological and supraphysiological flow conditions. Our preliminary results suggest that the reproduction of complex anatomic structures by rapid prototyping techniques may be useful to fabricate custom made polymeric scaffolds for the tissue engineering of heart valves.

  12. Fabrication of fibrinogen/P(LLA-CL) hybrid nanofibrous scaffold for potential soft tissue engineering applications.

    PubMed

    He, Chuanglong; Xu, Xiaohong; Zhang, Fan; Cao, Lijun; Feng, Wei; Wang, Hongsheng; Mo, Xiumei

    2011-06-01

    Coelectrospinning of native proteins and elastic synthetic polymers is an attractive technique to fabricate hybrid fibrous scaffolds that combine the bioactivity and mechanical features of each material component. In this study, hybrid fibrous scaffolds composed of synthetic P(LLA-CL) elastomeric and naturally derived fibrinogen protein were fabricated and characterized for their bioactive and physiochemical properties. Fiber diameters of hybrid scaffolds increased with increasing P(LLA-CL) content, and the shape of fibers changed from cylindrical shape on pure polymer scaffolds to flat structure on hybrid scaffolds. Characterizations of ATR-FTIR, XRD, and thermal properties indicated that the hybrid scaffolds contain two different phases, one composed of pure fibrinogen and the other corresponding to a mixture of fibrinogen and P(LLA-CL), and no obvious chemical reaction takes place between two components. The hybrid fibrous scaffolds showed tailorable degradation rates than pure P(LLA-CL) and higher mechanical properties than pure fibrinogen, and both tensile strength and breaking strain increased with increasing P(LLA-CL) content. In Vitro studies revealed that L929 cells on hybrid scaffolds achieved relatively higher level of cell attachment after 12 h of culture and significant increased cell proliferation rate after 7 days of culture, when compared with pure fibrinogen and P(LLA-CL) scaffolds, and the cells exhibited a spreading polygonal shape on the hybrid fibrous surfaces compared to a round shape on surfaces of pure polymer scaffolds. Therefore, the fibrinogen/P(LLA-CL) hybrid fibrous scaffolds possess the combined benefits of each individual component, which make it capable as scaffolds for soft tissue reconstruction.

  13. 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

  14. Net shape fabrication of calcium phosphate scaffolds with multiple material domains.

    PubMed

    Xie, Yangmin; Rustom, Laurence E; McDermott, Anna M; Boerckel, Joel D; Johnson, Amy J Wagoner; Alleyne, Andrew G; Hoelzle, David J

    2016-01-08

    Calcium phosphate (CaP) materials have been proven to be efficacious as bone scaffold materials, but are difficult to fabricate into complex architectures because of the high processing temperatures required. In contrast, polymeric materials are easily formed into scaffolds with near-net-shape forms of patient-specific defects and with domains of different materials; however, they have reduced load-bearing capacity compared to CaPs. To preserve the merits of CaP scaffolds and enable advanced scaffold manufacturing, this manuscript describes an additive manufacturing process that is coupled with a mold support for overhanging features; we demonstrate that this process enables the fabrication of CaP scaffolds that have both complex, near-net-shape contours and distinct domains with different microstructures. First, we use a set of canonical structures to study the manufacture of complex contours and distinct regions of different material domains within a mold. We then apply these capabilities to the fabrication of a scaffold that is designed for a 5 cm orbital socket defect. This scaffold has complex external contours, interconnected porosity on the order of 300 μm throughout, and two distinct domains of different material microstructures.

  15. Design and fabrication of biomimetic multiphased scaffolds for ligament-to-bone fixation.

    PubMed

    He, Jiankang; Zhang, Wenyou; Liu, Yaxiong; Li, Xiang; Li, Dichen; Jin, Zhongmin

    2015-05-01

    Conventional ligament grafts with single material composition cannot effectively integrate with the host bones due to mismatched properties and eventually affect their long-term function in vivo. Here we presented a multi-material strategy to design and fabricate composite scaffolds including ligament, interface and bone multiphased regions. The interface region consists of triphasic layers with varying material composition and porous structure to mimic native ligament-to-bone interface while the bone region contains polycaprolactone (PCL) anchor and microchanneled ceramic scaffolds to potentially provide combined mechanical and biological implant-bone fixation. Finite element analysis (FEA) demonstrated that the multiphased scaffolds with interference value smaller than 0.5 mm could avoid the fracture of ceramic scaffold during the implantation process, which was validated by in-vitro implanting the multiphased scaffolds into porcine joint bones. Pull-out experiment showed that the initial fixation between the multiphased scaffolds with 0.47 mm interference and the host bones could withstand the maximum force of 360.31±97.51 N, which can be improved by reinforcing the ceramic scaffolds with biopolymers. It is envisioned that the multiphased scaffold could potentially induce the regeneration of a new bone as well as interfacial tissue with the gradual degradation of the scaffold and subsequently realize long-term biological fixation of the implant with the host bone. PMID:25746239

  16. Fabrication of uniformly cell-laden porous scaffolds using a gas-in-liquid templating technique.

    PubMed

    Takei, Takayuki; Aokawa, Ryuta; Shigemitsu, Takamasa; Kawakami, Koei; Yoshida, Masahiro

    2015-11-01

    Design of porous scaffolds in tissue engineering field was challenging. Uniform immobilization of cells in the scaffolds with high porosity was essential for homogeneous tissue formation. The present study was aimed at fabricating uniformly cell-laden porous scaffolds with porosity >74% using the gas-in-liquid foam templating technique. To this end, we used gelatin, microbial transglutaminase and argon gas as a scaffold material, cross-linker of the protein and porogen of scaffold, respectively. We confirmed that a porosity of >74% could be achieved by increasing the gas volume delivered to a gelatin solution. Pore size in the scaffold could be controlled by stirring speed, stirring time and the pore size of the filter through which the gas passed. The foaming technique enabled us to uniformly immobilize a human hepatoblastoma cell line in scaffold. Engraftment efficiency of the cell line entrapped within the scaffold in nude mice was higher than that of cells in free-form. These results showed that the uniformly cell-laden porous scaffolds were promising for tissue engineering.

  17. Design and fabrication of biomimetic multiphased scaffolds for ligament-to-bone fixation.

    PubMed

    He, Jiankang; Zhang, Wenyou; Liu, Yaxiong; Li, Xiang; Li, Dichen; Jin, Zhongmin

    2015-05-01

    Conventional ligament grafts with single material composition cannot effectively integrate with the host bones due to mismatched properties and eventually affect their long-term function in vivo. Here we presented a multi-material strategy to design and fabricate composite scaffolds including ligament, interface and bone multiphased regions. The interface region consists of triphasic layers with varying material composition and porous structure to mimic native ligament-to-bone interface while the bone region contains polycaprolactone (PCL) anchor and microchanneled ceramic scaffolds to potentially provide combined mechanical and biological implant-bone fixation. Finite element analysis (FEA) demonstrated that the multiphased scaffolds with interference value smaller than 0.5 mm could avoid the fracture of ceramic scaffold during the implantation process, which was validated by in-vitro implanting the multiphased scaffolds into porcine joint bones. Pull-out experiment showed that the initial fixation between the multiphased scaffolds with 0.47 mm interference and the host bones could withstand the maximum force of 360.31±97.51 N, which can be improved by reinforcing the ceramic scaffolds with biopolymers. It is envisioned that the multiphased scaffold could potentially induce the regeneration of a new bone as well as interfacial tissue with the gradual degradation of the scaffold and subsequently realize long-term biological fixation of the implant with the host bone.

  18. Fabrication and Characterization of Three-Dimensional Macroscopic All-Carbon Scaffolds

    PubMed Central

    Lalwani, Gaurav; Kwaczala, Andrea Trinward; Kanakia, Shruti; Patel, Sunny C.; Judex, Stefan; Sitharaman, Balaji

    2012-01-01

    We report a simple method to fabricate macroscopic, 3-D, free standing, all-carbon scaffolds (porous structures) using multiwalled carbon nanotubes (MWCNTs) as the starting materials. The scaffolds prepared by radical initiated thermal crosslinking, and annealing of MWCNTs possess macroscale interconnected pores, robust structural integrity, stability, and conductivity. The porosity of the three-dimensional structure can be controlled by varying the amount of radical initiator, thereby allowing the design of porous scaffolds tailored towards specific potential applications. This method also allows the fabrication of 3-D scaffolds using other carbon nanomaterials such as single-walled carbon nanotubes, fullerenes, and graphene indicating that it could be used as a versatile method for 3-D assembly of carbon nanostructures with pi bond networks. PMID:23436939

  19. Tunable tissue scaffolds fabricated by in situ crosslink in phase separation system

    PubMed Central

    Liu, Xifeng; Chen, Wenjian; Gustafson, Carl T.; Miller, A. Lee; Waletzki, Brian E.; Yaszemski, Michael J.; Lu, Lichun

    2015-01-01

    Three-dimensional (3-D) scaffolds with intrinsic porous structures are desirable in various tissue regeneration applications. In this study, a unique method that combines thermally induced phase separation with a photocrosslinking process was developed for the fabrication of 3-D crosslinked polymer scaffolds with densely interconnected porous structures. Biodegradable poly(propylene fumarate)-co-poly(L-lactic acid) with crosslinkable fumarate bonds were used as the structural polymer material and a dioxane/water binary system was applied for the phase separation. By altering the polymer composition (9, 5 and 3 wt%), different types of scaffolds with distinct morphology, mechanical strength, degradation rate, cell growth and morphology, and extracellular matrix production were fabricated. These crosslinked 3-D porous scaffolds with tunable strength and biological responses show promise for potential applications in regenerative therapies, including bone and neural tissue engineering. PMID:26989479

  20. Bioactive composite gradient coatings of nano-hydroxyapatite/polyamide66 fabricated on polyamide66 substrates

    PubMed Central

    Huang, Di; Zuo, Yi; Li, Jidong; Zou, Qin; Zhang, Li; Gong, Mei; Wang, Li; Li, Limei; Li, Yubao

    2012-01-01

    Tightly bonding of bioactive coating is the first crucial need for orthopaedic implants. This study describes a novel and convenient technique to prepare bioactive coating with high adhesion on orthopaedic substitutes made of polymeric matrix. Here, a chemical corrosion method has been adopted to fabricate a coating on the surface of injection-moulded polyamide66 (PA66) substrates by corrosive nano-hydroxyapatite/polyamide66 (n-HA/PA66) composite slurry. Scanning electron microscopy observation shows that a porous chemical corrosion region presents between the coating and dense PA66 substrate. Energy-dispersive X-ray spectroscopy analysis indicates that the chemical corrosion region is mainly composed of PA66 matrix, and the coating layer is an n-HA-rich layer. Both the pore size and n-HA composition increase gradually from the polymeric substrate towards the coating surface. Mechanical testing shows the bonding strength can reach 13.7 ± 0.2 MPa, which is much higher than that fabricated on polymeric matrix by other coating methods. The gradual transition in coating structure and composition benefits for the interface bonding and for the surface bone-bonding bioactivity. Subsequent cell experiments corroborate n-HA-rich coating and a porous structure is benefitting for cell attachment and proliferation. The convenient coating method could be popularized and applied on similar polymer implants to produce a tightly and porous bioactive coating for bone tissue regeneration. PMID:22258549

  1. A mild one-pot process for synthesising hydroxyapatite/biomolecule bone scaffolds for sustained and controlled antibiotic release.

    PubMed

    Hess, Ulrike; Hill, Sebastian; Treccani, Laura; Streckbein, Philipp; Heiss, Christian; Rezwan, Kurosch

    2015-02-01

    The release of active molecules or the control of nosocomial infections for improved osteoinduction is ideally addressed by a bone substitute material. For this purpose, the feasibility of a mild one-pot process is probed for incorporating directly active proteins and antibiotics in a hydroxyapatite (HAp) based scaffold. The effect of two serum model proteins, bovine serum albumin (BSA) and fibrinogen (FIB), on the microstructure, on selected mechanical properties as well as on degradation behaviour and on protein release are investigated. By protein incorporation, the porosity can be adjusted between 54 and 70% especially due to the foaming ability of BSA. The addition of 5 wt% FIB doubles the biaxial flexural strength up to 6 MPa in comparison to samples without proteins (3 MPa). Protein release experiments show that a rapid release takes place within the first days (between around 3% for FIB and 38% for BSA). As a possible application for osteomyelitis treatment, vancomycin and gentamicin were subsequently added instead of proteins to study their release behaviour and their antibacterial activity, respectively. A controlled antibiotic release was observed for a period of 18 d. By varying the protein type, mixture and quantity, the mechanical strength porosity as well as the protein release and calcium solubility can be controlled. Our studies underpin the suitability of this mild one-pot process as a promising simple-to-use platform for controlled local drug release and bone treatment.

  2. Fabricating gradient hydrogel scaffolds for 3D cell culture.

    PubMed

    Chatterjee, Kaushik; Young, Marian F; Simon, Carl G

    2011-05-01

    Optimizing cell-material interactions is critical for maximizing regeneration in tissue engineering. Combinatorial and high-throughput (CHT) methods can be used to systematically screen tissue scaffolds to identify optimal biomaterial properties. Previous CHT platforms in tissue engineering have involved a two-dimensional (2D) cell culture format where cells were cultured on material surfaces. However, these platforms are inadequate to predict cellular response in a three-dimensional (3D) tissue scaffold. We have developed a simple CHT platform to screen cell-material interactions in 3D culture format that can be applied to screen hydrogel scaffolds. Herein we provide detailed instructions on a method to prepare gradients in elastic modulus of photopolymerizable hydrogels.

  3. Collagen scaffolds reinforced with biomimetic composite nano-sized carbonate-substituted hydroxyapatite crystals and shaped by rapid prototyping to contain internal microchannels.

    PubMed

    Sachlos, Eleftherios; Gotora, Duce; Czernuszka, Jan T

    2006-09-01

    The next generation of tissue engineering scaffolds will be made to accommodate blood vessels and nutrient channels to support cell survival deep in the interior of the scaffolds. To this end, we have developed a method that incorporates microchannels to permit the flow of nutrient-rich media through collagen-based scaffolds. The scaffold matrix comprises nano-sized carbonate-substituted hydroxyapatite (HA) crystals internally precipitated in collagen fibers. The scaffold therefore mimics many of the features found in bone. A biomimetic precipitation technique is used whereby a collagen membrane separates reservoirs of calcium and phosphate solutions. The collision of calcium and phosphate ions diffusing from opposite directions results in the precipitation of mineral within the collagen membrane. Transmission electron microscopy analysis showed the dimension of the mineral crystals to be approximately 180 x 80 x 20 nm, indicating that the crystals reside in the intermicrofibril gaps. Electron diffraction indicated that the mineral was in the HA phase, and infrared spectroscopy confirmed type A carbonate substitution. The collagen-HA membrane is then used to make 3-dimensional (3D) scaffolds: the membrane is shredded and mixed in an aqueous-based collagen dispersion and processed using the critical point drying method. Adjusting the pH of the dispersion to 5.0 before mixing the composite component preserved the nano-sized carbonate-substituted HA crystals. Branching and interconnecting microchannels in the interior of the scaffolds are made with a sacrificial mold manufactured by using a 3D wax printer. The 3D wax printer has been modified to print the mold from biocompatible materials. Appropriately sized microchannels within collagen-HA scaffolds brings us closer to fulfilling the mass transport requirements for osteogenic cells living deep within the scaffold.

  4. Collagen-gelatin-genipin-hydroxyapatite composite scaffolds colonized by human primary osteoblasts are suitable for bone tissue engineering applications: in vitro evidences.

    PubMed

    Vozzi, G; Corallo, C; Carta, S; Fortina, M; Gattazzo, F; Galletti, M; Giordano, N

    2014-05-01

    The application of porous hydroxyapatite (HAp)-collagen as a bone tissue engineering scaffold represents a new trend of mimicking the specific bone extracellular matrix (ECM). The use of HAp in reconstructive surgery has shown that it is slowly invaded by host tissue. Therefore, implant compatibility may be augmented by seeding cells before implantation. Human primary osteoblasts were seeded onto innovative collagen-gelatin-genipin (GP)-HAp scaffolds containing respectively 10%, 20%, and 30% HAp. Cellular adhesion, proliferation, alkaline phosphatase (ALP) activity, osteopontin (OPN), and osteocalcin (OC) expressions were evaluated after 3, 7, 15, and 21 days. The three types of scaffolds showed increased cellular proliferation over time in culture (maximum at 21 days) but the highest was recorded in 10% HAp scaffolds. ALP activity was the highest in 10% HAp scaffolds in all the times of evaluation. OC and OPN resulted in higher concentration in 10% HAp scaffolds compared to 20% and 30% HAp (maximum at 21 days). Finally, scanning electron microscopy analysis showed progressive scaffolds adhesion and colonization from the surface to the inside from day 3 to day 21. In vitro attachment, proliferation, and colonization of human primary osteoblasts on collagen-GP-HAp scaffolds with different percentages of HAp (10%, 20%, and 30%) all increased over time in culture, but comparing different percentages of HAp, they seem to increase with decreasing of HAp component. Therefore, the mechanical properties (such as the stiffness due to the HAp%) coupled with a good biomimetic component (collagen) are the parameters to set up in composite scaffolds design for bone tissue engineering. PMID:23775901

  5. Towards the Design of 3D Fiber-Deposited Poly(ε-caprolactone)/lron-Doped Hydroxyapatite Nanocomposite Magnetic Scaffolds for Bone Regeneration.

    PubMed

    De Santis, Roberta; Russo, Alessandro; Gloria, Antonio; D'Amora, Ugo; Russo, Teresa; Panseri, Silvia; Sandri, Monica; Tampieri, Anna; Marcacci, Maurilio; Dediu, Valentin A; Wilde, Colin J; Ambrosio, Luigi

    2015-07-01

    In the past few years, researchers have focused on the design and development of three-dimensional (3D) advanced scaffolds, which offer significant advantages in terms of cell performance. The introduction of magnetic features into scaffold technology could offer innovative opportunities to control cell populations within 3D microenvironments, with the potential to enhance their use in tissue regeneration or in cell-based analysis. In the present study, 3D fully biodegradable and magnetic nanocomposite scaffolds for bone tissue engineering, consisting of a poly(ε-caprolactone) (PCL) matrix reinforced with iron-doped hydroxyapatite (FeHA) nanoparticles, were designed and manufactured using a rapid prototyping technique. The performances of these novel 3D PCL/FeHA scaffolds were assessed through a combination of theoretical evaluation, experimental in vitro analyses and in vivo testing in a rabbit animal model. The results from mechanical com- pression tests were consistent with FEM simulations. The in vitro results showed that the cell growth in the magnetized scaffolds was 2.2-fold greater than that in non-magnetized ones. In vivo experiments further suggested that, after only 4 weeks, the PCL/FeHA scaffolds were completely filled with newly formed bone, proving a good level of histocompatibility. All of the results suggest that the introduction of magnetic features into biocompatible materials may confer significant advantages in terms of 3D cell assembly. PMID:26307846

  6. Techniques for fabrication and construction of three-dimensional scaffolds for tissue engineering

    PubMed Central

    Lu, Tingli; Li, Yuhui; Chen, Tao

    2013-01-01

    Three-dimensional biomimetic scaffolds have widespread applications in biomedical tissue engineering because of their nanoscaled architecture, eg, nanofibers and nanopores, similar to the native extracellular matrix. In the conventional “top-down” approach, cells are seeded onto a biocompatible and biodegradable scaffold, in which cells are expected to populate in the scaffold and create their own extracellular matrix. The top-down approach based on these scaffolds has successfully engineered thin tissues, including skin, bladder, and cartilage in vitro. However, it is still a challenge to fabricate complex and functional tissues (eg, liver and kidney) due to the lack of vascularization systems and limited diffusion properties of these large biomimetic scaffolds. The emerging “bottom-up” method may hold great potential to address these challenges, and focuses on fabricating microscale tissue building blocks with a specific microarchitecture and assembling these units to engineer larger tissue constructs from the bottom up. In this review, state-of-the-art methods for fabrication of three-dimensional biomimetic scaffolds are presented, and their advantages and drawbacks are discussed. The bottom-up methods used to assemble microscale building blocks (eg, microscale hydrogels) for tissue engineering are also reviewed. Finally, perspectives on future development of the bottom-up approach for tissue engineering are addressed. PMID:23345979

  7. Strategic Design and Fabrication of Engineered Scaffolds for Articular Cartilage Repair

    PubMed Central

    Izadifar, Zohreh; Chen, Xiongbiao; Kulyk, William

    2012-01-01

    Damage to articular cartilage can eventually lead to osteoarthritis (OA), a debilitating, degenerative joint disease that affects millions of people around the world. The limited natural healing ability of cartilage and the limitations of currently available therapies make treatment of cartilage defects a challenging clinical issue. Hopes have been raised for the repair of articular cartilage with the help of supportive structures, called scaffolds, created through tissue engineering (TE). Over the past two decades, different designs and fabrication techniques have been investigated for developing TE scaffolds suitable for the construction of transplantable artificial cartilage tissue substitutes. Advances in fabrication technologies now enable the strategic design of scaffolds with complex, biomimetic structures and properties. In particular, scaffolds with hybrid and/or biomimetic zonal designs have recently been developed for cartilage tissue engineering applications. This paper reviews critical aspects of the design of engineered scaffolds for articular cartilage repair as well as the available advanced fabrication techniques. In addition, recent studies on the design of hybrid and zonal scaffolds for use in cartilage tissue repair are highlighted. PMID:24955748

  8. Fabrication of fibrin based electrospun multiscale composite scaffold for tissue engineering applications.

    PubMed

    Sreerekha, P R; Menon, Deepthy; Nair, S V; Chennazhi, K P

    2013-05-01

    Fabricating scaffolds mimicking the native extracellular matrix (ECM) in both structure and function is a key challenge in the field of tissue engineering. Previously we have demonstrated a novel electrospinnig method for the fabrication of fibrin nanofibers using Poly(vinyl alcohol) (PVA) as an 'electrospinning-driving' polymer. Here we demonstrate the fabrication and characterization of a multiscale fibrin based composite scaffold with polycaprolactone (PCL) by sequential electrospinning of PCL microfibers and fibrin nanofibers. This multiscale scaffold has great potential for tissue engineering applications due to the combined benefits of biological nanofibers such as cell attachment and proliferation and that of microfibers such as open structure, larger pore size and adequate mechanical strength. Physico chemical characterization of the electrospun scaffold was done by Scanning Electron Microscopy (SEM), Contact angle analysis, fibrin specific Phosphotungstic acid haematoxyllin (PTAH) staining and evaluation of mechanical properties. SEM data revealed the formation of bead free nanofibers of fibrin with a fiber diameter ranging from 50-500 nm and microfibers of PCL in the size range of 1 microns to 2.5 microns. These dimensions mimic the hierarchical structure of ECM found in native tissues. Cell attachment and viability studies using human mesenchymal stem cells (hMSC) revealed that the scaffold is non toxic and supports cell attachment, spreading and proliferation. In addition, we examined the inflammatory potential of the scaffold to demonstrate its usefulness in tissue engineering applications.

  9. Techniques for fabrication and construction of three-dimensional scaffolds for tissue engineering.

    PubMed

    Lu, Tingli; Li, Yuhui; Chen, Tao

    2013-01-01

    Three-dimensional biomimetic scaffolds have widespread applications in biomedical tissue engineering because of their nanoscaled architecture, eg, nanofibers and nanopores, similar to the native extracellular matrix. In the conventional "top-down" approach, cells are seeded onto a biocompatible and biodegradable scaffold, in which cells are expected to populate in the scaffold and create their own extracellular matrix. The top-down approach based on these scaffolds has successfully engineered thin tissues, including skin, bladder, and cartilage in vitro. However, it is still a challenge to fabricate complex and functional tissues (eg, liver and kidney) due to the lack of vascularization systems and limited diffusion properties of these large biomimetic scaffolds. The emerging "bottom-up" method may hold great potential to address these challenges, and focuses on fabricating microscale tissue building blocks with a specific microarchitecture and assembling these units to engineer larger tissue constructs from the bottom up. In this review, state-of-the-art methods for fabrication of three-dimensional biomimetic scaffolds are presented, and their advantages and drawbacks are discussed. The bottom-up methods used to assemble microscale building blocks (eg, microscale hydrogels) for tissue engineering are also reviewed. Finally, perspectives on future development of the bottom-up approach for tissue engineering are addressed.

  10. ELECTRICALLY CONDUCTIVE SURFACE MODIFICATIONS OF THREE-DIMENSIONAL POLYPROPYLENE FUMARATE SCAFFOLDS

    PubMed Central

    Runge, M. Brett; Dadsetan, Mahrokh; Baltrusaitis, Jonas; Yaszemski, Michael J.

    2014-01-01

    Summary Polypropylene fumarate (PPF) scaffolds fabricated by rapid prototyping technique were surface modified by solution deposition of electrically conductive polypyrrole coatings with or without hydroxyapatite. Scaffolds were electrically conductive with resistivity as low as 2Ω. Scaffold characterization by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and thermo gravimetric analysis shows both polypyrrole and hydroxyapatite are present. Cell viability, attachment, proliferation, and differentiation were analyzed using human fetal osteoblast cells. These studies show that surface modification using hydroxyapatite improved cell attachment and proliferation of osteoblasts onto the PPF scaffolds. Alkaline phosphatase activity as a marker for osteogenic differentiation of cell to mature osteoblasts was analyzed. Our data reveal that osteoblasts maintained their phenotype on PPF scaffolds with and without coatings. Thus, these scaffolds could be appropriate candidates for our future in vivo studies. PMID:22051167

  11. An Exhibition and Analysis of Verbal Tapestries: Understanding How Scaffolding Is Woven into the Fabric of Instructional Conversations.

    ERIC Educational Resources Information Center

    Many, Joyce E.

    2002-01-01

    Examines conversations between teachers and students and between peers to describe the nature of the instructional scaffolding that occurred as students constructed meaning of literary and nonfiction texts. Describes ways in which scaffolding was woven in and out of the fabric of the conversations. Finds that episodes of scaffolded instruction…

  12. Modern materials in fabrication of scaffolds for bone defect replacement

    NASA Astrophysics Data System (ADS)

    Bazlov, V. A.; Mamuladze, T. Z.; Pavlov, V. V.; Kirilova, I. A.; Sadovoy, M. A.

    2016-08-01

    The article defines the requirements for modern scaffold-forming materials and describes the main advantages and disadvantages of various synthetic materials. Osseointegration of synthetic scaffolds approved for use in medical practice is evaluated. Nylon 618 (certification ISO9001 1093-1-2009) is described as the most promising synthetic material used in medical practice. The authors briefly highlight the issues of individual bone grafting with the use of 3D printing technology. An example of contouring pelvis defect after removal of a giant tumor with the use of 3D models is provided.

  13. Fabrication of Tissue Engineering Scaffolds through Solid-state Foaming of Immiscible Polymer Blends

    PubMed Central

    Zhou, Changchun; Ma, Liang; Li, Wei; Yao, Donggang

    2011-01-01

    In scaffold-based tissue engineering, the fabrication process is important for producing suitable microstructures for seeded cells to grow and reformulate. In this paper, we present a new approach to scaffold fabrication by combining the solid-state foaming and the immiscible polymer blending method. The proposed approach has the advantage of being versatile and able to create a wide range of pore size and porosity. The proposed method is studied with polylactic acid (PLA) and polystyrene (PS) blends. The interconnected porous structure was created by first foaming the PLA/PS blend and then extracting the PS phase. The solid-state foaming experiments were conducted under various conditions to achieve the desired pore sizes. It is shown that the PS phase of the PLA/PS blend can be extracted much faster in the foamed samples and the pore size of the scaffolds can be easily controlled with proper gas foaming parameters. The average pore size achieved in the foaming process ranged from 20-70 μm. After PS extraction, both pore size and porosity can be further improved. For example, the pore size and porosity increased from 48 μm and 49% to 59 μm and 67%, respectively, after the PS extraction process. The fabricated porous scaffolds were used to culture human osteoblast cells. Cells grew well and gradually formed a fibrous structure. The combined solid-state foaming and immiscible polymer blending method provides a new technique for fabricating tissue engineering scaffolds. PMID:21904025

  14. High-precision flexible fabrication of tissue engineering scaffolds using distinct polymers

    SciTech Connect

    Wei, Chuang; Cai, Lei; Sonawane, Bhushan; Wang, Shanfeng; Dong, Jingyan

    2012-01-01

    Three-dimensional porous structures using biodegradable materials with excellent biocompatibility are critically important for tissue engineering applications. We present a multi-nozzle-based versatile deposition approach to flexibly construct porous tissue engineering scaffolds using distinct polymeric biomaterials such as thermoplastic and photo-crosslinkable polymers. We first describe the development of the deposition system and fabrication of scaffolds from two types of biodegradable polymers using this system. The thermoplastic sample is semi-crystalline poly({var_epsilon}-caprolactone) (PCL) that can be processed at a temperature higher than its melting point and solidifies at room temperature. The photo-crosslinkable one is polypropylene fumarate (PPF) that has to be dissolved in a reactive solvent as a resin for being cured into solid structures. Besides the direct fabrication of thermoplastic PCL scaffolds, we specifically develop a layer molding approach for the fabrication of crosslinkable polymers, which traditionally can only be fabricated by stereolithography. In this approach, a thermoplastic supporting material (paraffin wax) is first deposited to make a mold for each specific layer, and then PPF is deposited on demand to fill the mold and cured by the UV light. The supporting material can be removed to produce a porous scaffold of crosslinked PPF. Both PCL and crosslinked PPF scaffolds fabricated using the developed system have been characterized in terms of compressive mechanical properties, morphology, pore size and porosity. Mouse MC3T3-E1 pre-osteoblastic cell studies on the fabricated scaffolds have been performed to demonstrate their capability of supporting cell proliferation and ingrowth, aiming for bone tissue engineering applications.

  15. Recent prospective of nanofiber scaffolds fabrication approaches for skin regeneration.

    PubMed

    Ahmadi-Aghkand, Fateme; Gholizadeh-Ghaleh Aziz, Shiva; Panahi, Yunes; Daraee, Hadis; Gorjikhah, Fateme; Gholizadeh-Ghaleh Aziz, Sara; Hsanzadeh, Arash; Akbarzadeh, Abolfazl

    2016-11-01

    The largest organ of human body is skin, which acting as a barrier with immunologic, sensorial and protective functions. It is always in exposure to the external environment, which can result many different types of damage and injury with loss of variable volumes of extracellular matrix (ECM). For the treatment of skin lesions and damages, several approaches are now accessible, such as the application of allografts, autografts, and tissue-engineered substitutes, wound dressings and nanofiber scaffolds approaches. Even though proven clinically effective, these methods are still characterized by main drawbacks such as patient inadequate vascularization, morbidity, the inability to reproduce skin appendages, low adherence to the wound bed and high manufacturing costs. Advanced approaches based on nanofiber scaffolds approaches offer a permanent, viable and effective substitute to explain the drawbacks of skin regeneration and repair by combining growth factors, cells, and biomaterials and advanced biomanufacturing methods. This review details recent advances of nanofiber scaffolds in skin regeneration and repair strategies, and describes a synthesis method of nanofiber scaffolds.

  16. 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.

  17. Effect of hydroxyapatite-containing microspheres embedded into three-dimensional magnesium phosphate scaffolds on the controlled release of lysozyme and in vitro biodegradation

    PubMed Central

    Lee, Jongman; Yun, Hui-suk

    2014-01-01

    The functionality of porous three-dimensional (3D) magnesium phosphate (MgP) scaffold was investigated for the development of a novel protein delivery system and biomimetic bone tissue engineering scaffold. This enhancement can be achieved by incorporation of hydroxyapatite (HA)-containing polymeric microspheres (MSs) into a bulk MgP matrix, and a paste-extruding deposition (PED) system. In this work, the amount of MS and HA was precisely controlled when manufacturing MS-embedded MgP (MS/MgP) composite scaffolds. The main influence was researched in terms of in vitro lysozyme-release, in vitro biodegradation, mechanical properties, and in vitro calcification. The controlled release of lysozyme was indicated, while showing graded release patterns according to HA content. The composite scaffolds degraded gradually with MS content and degradation time. Due to the effect of HA inclusion, the higher HA-containing MS/MgP scaffolds could, not only delay the biodegradation process but also, compensate for the possible loss of mechanical properties. In this regard, it is reasonable to confirm the inverse relationship between biodegradation and corresponding compressive properties. In order to encourage bioactivity and osteoconductivity, the MS/MgP composite scaffolds were subjected to simulated body fluid treatment. Calcium deposition was, in turn, improved with increasing MS and HA content over time. This quantitative result was also proved using morphological and elemental analysis. In summary, a significant transformation of a monolithic MgP scaffold was directed toward a multifunctional bone tissue engineering scaffold equipped with controlled protein delivery, biodegradability, and bioactivity. PMID:25214782

  18. Systematic fabrication of nano-carbonated hydroxyapatite/collagen composites for biomimetic bone grafts.

    PubMed

    Liao, Susan; Ngiam, Michelle; Watari, Fumio; Ramakrishna, Seeram; Chan, Casey K

    2007-09-01

    A novel biomimetic self-assembly method was designed to create nano-carbonated hydroxyapatite/collagen (nCHAC) composites by means of incorporating various collagen and carbonate concentrations using solutions such as CaCl(2), H(3)PO(4), and Na(2)CO(3). At a given range of collagen and carbonate content, the nanosized inorganic phase of the newly synthesized material has a low degree of crystallinity which resembles that of natural bone. By manipulating the concentrations of collagen and carbonates, various morphologies of the nCHAC can be obtained. The crystal size of nCHAC is dependent on the concentration of carbonate and collagen present in the composites. For instance, higher collagen concentration results in smaller crystal nCHAC crystal size. Conversely, the higher the carbonate content, the smaller are the crystal size and the collagen fibril assembly. As the carbonate content increased, the plate-like crystals first became needle-like structures, subsequently short needle-like crystals and eventually became spherical particles. From this study, our method showcased the flexibility of fabricating various types of nCHAC composites which can be designed for different bone applications.

  19. Histological Comparison in Rats between Carbonate Apatite Fabricated from Gypsum and Sintered Hydroxyapatite on Bone Remodeling

    PubMed Central

    Ayukawa, Yasunori; Suzuki, Yumiko; Tsuru, Kanji; Koyano, Kiyoshi; Ishikawa, Kunio

    2015-01-01

    Carbonate apatite (CO3Ap), the form of apatite found in bone, has recently attracted attention. The purpose of the present study was to histologically evaluate the tissue/cellular response toward the low-crystalline CO3Ap fabricated using a dissolution-precipitation reaction with set gypsum as a precursor. When set gypsum was immersed in a 100°C 1 mol/L Na3PO4 aqueous solution for 24 h, the set gypsum transformed into CO3Ap. Both CO3Ap and sintered hydroxyapatite (s-HAp), which was used as a control, were implanted into surgically created tibial bone defects of rats for histological evaluation. Two and 4 weeks after the implantation, histological sections were created and observed using light microscopy. The CO3Ap granules revealed both direct apposition of the bone matrix by osteoblasts and osteoclastic resorption. In contrast, the s-HAp granules maintained their contour even after 4 weeks following implantation which implied that there was a lack of replacement into the bone. The s-HAp granules were sometimes encapsulated with fibrous tissue, and macrophage polykaryon was occasionally observed directly apposed to the implanted granules. From the viewpoint of bone remodeling, the CO3Ap granules mimicked the bone matrix, suggesting that CO3Ap may be an appropriate bone substitute. PMID:26504813

  20. Histological Comparison in Rats between Carbonate Apatite Fabricated from Gypsum and Sintered Hydroxyapatite on Bone Remodeling.

    PubMed

    Ayukawa, Yasunori; Suzuki, Yumiko; Tsuru, Kanji; Koyano, Kiyoshi; Ishikawa, Kunio

    2015-01-01

    Carbonate apatite (CO3Ap), the form of apatite found in bone, has recently attracted attention. The purpose of the present study was to histologically evaluate the tissue/cellular response toward the low-crystalline CO3Ap fabricated using a dissolution-precipitation reaction with set gypsum as a precursor. When set gypsum was immersed in a 100°C 1 mol/L Na3PO4 aqueous solution for 24 h, the set gypsum transformed into CO3Ap. Both CO3Ap and sintered hydroxyapatite (s-HAp), which was used as a control, were implanted into surgically created tibial bone defects of rats for histological evaluation. Two and 4 weeks after the implantation, histological sections were created and observed using light microscopy. The CO3Ap granules revealed both direct apposition of the bone matrix by osteoblasts and osteoclastic resorption. In contrast, the s-HAp granules maintained their contour even after 4 weeks following implantation which implied that there was a lack of replacement into the bone. The s-HAp granules were sometimes encapsulated with fibrous tissue, and macrophage polykaryon was occasionally observed directly apposed to the implanted granules. From the viewpoint of bone remodeling, the CO3Ap granules mimicked the bone matrix, suggesting that CO3Ap may be an appropriate bone substitute. PMID:26504813

  1. Improved fabrication of melt electrospun tissue engineering scaffolds using direct writing and advanced electric field control.

    PubMed

    Ristovski, Nikola; Bock, Nathalie; Liao, Sam; Powell, Sean K; Ren, Jiongyu; Kirby, Giles T S; Blackwood, Keith A; Woodruff, Maria A

    2015-03-25

    Direct writing melt electrospinning is an additive manufacturing technique capable of the layer-by-layer fabrication of highly ordered 3d tissue engineering scaffolds from micron-diameter fibers. The utility of these scaffolds, however, is limited by the maximum achievable height of controlled fiber deposition, beyond which the structure becomes increasingly disordered. A source of this disorder is charge build-up on the deposited polymer producing unwanted coulombic forces. In this study, the authors introduce a novel melt electrospinning platform with dual voltage power supplies to reduce undesirable charge effects and improve fiber deposition control. The authors produced and characterized several 90° cross-hatched fiber scaffolds using a range of needle/collector plate voltages. Fiber thickness was found to be sensitive only to overall potential and invariant to specific tip/collector voltage. The authors also produced ordered scaffolds up to 200 layers thick (fiber spacing 1 mm and diameter 40 μm) and characterized structure in terms of three distinct zones: ordered, semiordered, and disordered. Our in vitro analysis indicates successful cell attachment and distribution throughout the scaffolds, with little evidence of cell death after seven days. This study demonstrates the importance of electrostatic control for reducing destabilizing polymer charge effects and enabling the fabrication of morphologically suitable scaffolds for tissue engineering.

  2. Fabrication of computationally designed scaffolds by low temperature 3D printing.

    PubMed

    Castilho, Miguel; Dias, Marta; Gbureck, Uwe; Groll, Jürgen; Fernandes, Paulo; Pires, Inês; Gouveia, Barbara; Rodrigues, Jorge; Vorndran, Elke

    2013-09-01

    The development of artificial bone substitutes that mimic the properties of bone and simultaneously promote the desired tissue regeneration is a current issue in bone tissue engineering research. An approach to create scaffolds with such characteristics is based on the combination of novel design and additive manufacturing processes. The objective of this work is to characterize the microstructural and the mechanical properties of scaffolds developed by coupling both topology optimization and a low temperature 3D printing process. The scaffold design was obtained using a topology optimization approach to maximize the permeability with constraints on the mechanical properties. This procedure was studied to be suitable for the fabrication of a cage prototype for tibial tuberosity advancement application, which is one of the most recent and promising techniques to treat cruciate ligament rupture in dogs. The microstructural and mechanical properties of the scaffolds manufactured by reacting α/β-tricalcium phosphate with diluted phosphoric acid were then assessed experimentally and the scaffolds strength reliability was determined. The results demonstrate that the low temperature 3D printing process is a reliable option to create synthetic scaffolds with tailored properties, and when coupled with topology optimization design it can be a powerful tool for the fabrication of patient-specific bone implants. PMID:23887064

  3. Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds.

    PubMed

    Mohanty, Soumyaranjan; Larsen, Layla Bashir; Trifol, Jon; Szabo, Peter; Burri, Harsha Vardhan Reddy; Canali, Chiara; Dufva, Marin; Emnéus, Jenny; Wolff, Anders

    2015-10-01

    One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible to achieve 80% porosity corresponding to about 150 cm(2)/cm(3) surface to volume ratio. The process is easily scalable as demonstrated by fabricating a 75 cm(3) scaffold with about 16,000 interconnected channels (about 1m(2) surface area) and with a channel to channel distance of only 78 μm. To our knowledge this is the largest scaffold ever to be produced with such small feature sizes and with so many structured channels. The fabricated scaffolds were applied for in-vitro culturing of hepatocytes over a 12-day culture period. Smaller scaffolds (6×4 mm) were tested for cell culturing and could support homogeneous cell growth throughout the scaffold. Presumably, the diffusion of oxygen and nutrient throughout the channel network is rapid enough to support cell growth. In conclusion, the described process is scalable, compatible with cell culture, rapid, and inexpensive. PMID:26117791

  4. Laser sintering fabrication of three-dimensional tissue engineering scaffolds with a flow channel network.

    PubMed

    Niino, T; Hamajima, D; Montagne, K; Oizumi, S; Naruke, H; Huang, H; Sakai, Y; Kinoshita, H; Fujii, T

    2011-09-01

    The fabrication of tissue engineering scaffolds for the reconstruction of highly oxygen-dependent inner organs is discussed. An additive manufacturing technology known as selective laser sintering was employed to fabricate a highly porous scaffold with an embedded flow channel network. A porogen leaching system was used to obtain high porosity. A prototype was developed using the biodegradable plastic polycaprolactone and sodium chloride as the porogen. A high porosity of 90% was successfully obtained. Micro x-ray CT observation was carried out to confirm that channels with a diameter of approximately 1 mm were generated without clogging. The amount of residual salt was 930 µg while the overall volume of the scaffold was 13 cm(3), and it was confirmed that the toxicity of the salt was negligible. The hydrophilization of the scaffold to improve cell adhesion on the scaffold is also discussed. Oxygen plasma ashing and hydrolysis with sodium hydroxide, typically employed to improve the hydrophilicity of plastic surfaces, were tested. The improvement of hydrophilicity was confirmed by an increase in water retention by the porous scaffold from 180% to 500%.

  5. Bicomponent electrospinning to fabricate three-dimensional hydrogel-hybrid nanofibrous scaffolds with spatial fiber tortuosity.

    PubMed

    Jin, Gyuhyung; Lee, Slgirim; Kim, Seung-Hyun; Kim, Minhee; Jang, Jae-Hyung

    2014-12-01

    Electrospun fibrous mats have emerged as powerful tissue engineering scaffolds capable of providing highly effective and versatile physical guidance, mimicking the extracellular environment. However, electrospinning typically produces a sheet-like structure, which is a major limitation associated with current electrospinning technologies. To address this challenge, highly porous, volumetric hydrogel-hybrid fibrous scaffolds were fabricated by one Taylor cone-based side-by-side dual electrospinning of poly (ε-caprolactone) (PCL) and poly (vinyl pyrrolidone) (PVP), which possess distinct properties (i.e., hydrophobic and hydrogel properties, respectively). Immersion of the resulting scaffolds in water induced spatial tortuosity of the hydrogel PVP fibers while maintaining their aligned fibrous structures in parallel with the PCL fibers. The resulting conformational changes in the entire bicomponent fibers upon immersion in water led to volumetric expansion of the fibrous scaffolds. The spatial fiber tortuosity significantly increased the pore volumes of electrospun fibrous mats and dramatically promoted cellular infiltration into the scaffold interior both in vitro and in vivo. Harmonizing the flexible PCL fibers with the soft PVP-hydrogel layers produced highly ductile fibrous structures that could mechanically resist cellular contractile forces upon in vivo implantation. This facile dual electrospinning followed by the spatial fiber tortuosity for fabricating three-dimensional hydrogel-hybrid fibrous scaffolds will extend the use of electrospun fibers toward various tissue engineering applications.

  6. Assessment of cellular viability on calcium sulphate/hydroxyapatite injectable scaffolds

    PubMed Central

    Naudi, Kurt; Dalby, Matthew J; Tanner, K Elizabeth; McMahon, Jeremy D; Ayoub, Ashraf

    2013-01-01

    Cements for maxillofacial reconstruction of jaw defects through calcification of rotated muscle have been tested. The objective of this study was to investigate the visibility of loading of two types of commercially available cements, Cerament™ Spine Support and Cerament Bone Void Filler with mesenchymal cells and cytokines (bone morphogenetic protein) to act as a biomimetic scaffolding for future clinical application. Determination of basic biocompatibility (cell viability) using methyl thiazolyl tetrazolium and live/dead assay was carried out using MG-63 cells at various time points. Next, in order to inform potential subsequent in vivo experiments, a collagen tissue mimic was used for characterization of rabbit mesenchymal stromal cells using immunofluorescent cytoskeleton staining, and simultaneous and then sequential injection of Cerament Spine Support cement and cells into collagen gels. Results indicated that Cerament Spine Support was more biocompatible and that sequential injection of cement and then rabbit mesenchymal stromal cells into the tissue mimics is an optimal approach for clinical applications. PMID:24555009

  7. Composite scaffolds of nano-hydroxyapatite and silk fibroin enhance mesenchymal stem cell-based bone regeneration via the interleukin 1 alpha autocrine/paracrine signaling loop.

    PubMed

    Liu, Hua; Xu, Guo Wei; Wang, Ya Fei; Zhao, Hong Shi; Xiong, Si; Wu, Yan; Heng, Boon Chin; An, Cheng Rui; Zhu, Gang Hua; Xie, Ding Hua

    2015-05-01

    Composite scaffolds of nano-hydroxyapatite (nHAp) and silk fibroin (SF) have been reported to promote bone regeneration mainly through signaling pathways associated with cell-biomaterial interaction. However, it is unclear whether soluble factors also play a role in osteoinduction with nHAp-SF. In this study, we confirmed the biocompatibility and superior osteoinductivity of nHAp-SF scaffolds versus SF scaffolds both in vitro and on a calvarial defect model in vivo. This was followed by further analysis with microarray assay. The cDNA microarray results identified 247 differentially expressed genes in bone marrow mesenchymal stem cells (BMSCs) cultured on SF-nHAp scaffolds versus SF scaffolds. The greatest disparity in gene expression levels were observed with Il1α and Ilr2. Real-time PCR assay validated the results. The addition of IL-1α into cultures of BMSCs with SF significantly increased both Bmp2 and Ilr2 expression. However, with BMSCs alone, the Il1r2 expression increased substantially, whereas Bmp2 expression exhibited a decrease rather than increase. These data suggested that nHAp may exert osteoinductive effects on BMSCs via the secretion of IL-1α in an autocrine/paracrine fashion, and IL-1α activity could be regulated through the synthesis of IL1R2 by BMSCs upon interaction with nHAp. These results complemented our understanding of the underlying mechanisms of biomaterial osteoinductivity.

  8. Porous poly(ε-caprolactone) scaffolds for load-bearing tissue regeneration: solventless fabrication and characterization.

    PubMed

    Allaf, Rula M; Rivero, Iris V; Abidi, Noureddine; Ivanov, Ilia N

    2013-08-01

    Three-dimensional interconnected porous poly(ε-caprolactone) scaffolds have been prepared by a novel solventless scaffold fabrication approach combining cryomilling and compression molding/porogen leaching techniques. This study investigated the effects of processing parameters on scaffold morphology and properties for tissue regeneration. Specifically, the effects of molding temperature, cryomilling time, and porogen mix were examined. Fifty percentage of porous scaffolds were fabricated with a range of properties: mean pore size from ∼40 to 125 μm, water uptake from ∼50 to 86%, compressive modulus from ∼45 to 84 MPa, and compressive strength at 10% strain from ∼3 to 4 MPa. Addition of 60 wt % NaCl salt resulted in a ∼50% increase in porosity in multimodal pore-size structures that depended on the method of NaCl addition. Water uptake ranged from ∼61 to 197%, compressive modulus from ∼4 to 8.6 MPa, and compressive strength at 10% strain from ∼0.36 to 0.40 MPa. Results suggest that this approach provides a controllable strategy for the design and fabrication of 3D interconnected porous biodegradable scaffolds for load-bearing tissue regeneration.

  9. PCL/alginate composite scaffolds for hard tissue engineering: fabrication, characterization, and cellular activities.

    PubMed

    Kim, Yong Bok; Kim, Geun Hyung

    2015-02-01

    Alginates have been used widely in biomedical applications because of good biocompatibility, low cost, and rapid gelation in the presence of calcium ions. However, poor mechanical properties and fabrication-ability for three-dimensional shapes have been obstacles in hard-tissue engineering applications. To overcome these shortcomings of alginates, we suggest a new composite system, consisting of a synthetic polymer, poly(ε-caprolactone), and various weight fractions (10-40 wt %) of alginate. The fabricated composite scaffolds displayed a multilayered 3D structure, consisting of microsized composite struts, and they provided a 100% offset for each layer. To show the feasibility of the scaffold for hard tissue regeneration, the composite scaffolds fabricated were assessed not only for physical properties, including surface roughness, tensile strength, and water absorption and wetting, but also in vitro osteoblastic cellular responses (cell-seeding efficiency, cell viability, fluorescence analyses, alkaline phosphatase (ALP) activity, and mineralization) by culturing with preosteoblasts (MC3T3-E1). Due to the alginate components in the composites, the scaffolds showed significantly enhanced wetting behavior, water-absorption (∼12-fold), and meaningful biological activities (∼2.1-fold for cell-seeding efficiency, ∼2.5-fold for cell-viability at 7 days, ∼3.4-fold for calcium deposition), compared with a pure PCL scaffold.

  10. Fabrication and characterization of porous EH scaffolds and EH-PEG bilayers.

    PubMed

    Falco, Erin E; Coates, Emily E; Li, Erik; Roth, J Scott; Fisher, John P

    2011-06-01

    Biomaterials made from synthetic polymers are becoming more pervasive in the medical field. Synthetic polymers are particularly advantageous as their chemical and mechanical properties can be easily tailored to a specific application. This work characterizes polymer scaffolds derived from the cyclic acetal monomer 5-ethyl-5-(hydroxymethyl)-β,β-dimethyl-1,3-dioxane-2-ethanol diacrylate (EHD). Both porous scaffolds and bilayer scaffolds based upon the EHD monomer were fabricated, and the resulting scaffolds' degradation and mechanical properties were studied. The results showed that by modifying the architecture of an EH scaffold, either by adding a porous network or a poly(ethylene glycol) (PEG) coating, the degradation and Young's modulus of the biomaterial can be significant altered. However, results also indicated that these architectural modifications can be accomplished without a significant loss in the flexural strength of the scaffold. Therefore, we suggest that porous EH scaffolds, and particularly porous EH-PEG bilayers, may be especially useful in dynamic tissue environments due to their advantageous architectural and mechanical properties. PMID:21442727

  11. 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

  12. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds.

    PubMed

    Sun, Kai; Li, Ruixin; Jiang, Wenxue; Sun, Yufu; Li, Hui

    2016-09-01

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young's modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. PMID:27404126

  13. Laser fabrication of three-dimensional CAD scaffolds from photosensitive gelatin for applications in tissue engineering.

    PubMed

    Ovsianikov, Aleksandr; Deiwick, Andrea; Van Vlierberghe, Sandra; Dubruel, Peter; Möller, Lena; Dräger, Gerald; Chichkov, Boris

    2011-04-11

    In the present work, 3D CAD scaffolds for tissue engineering applications were developed starting from methacrylamide-modified gelatin (GelMOD) using two-photon polymerization (2PP). The scaffolds were cross-linked employing the biocompatible photoinitiator Irgacure 2959. Because gelatin is derived from collagen (i.e., the main constituent of the ECM), the developed materials mimic the cellular microenvironment from a chemical point of view. In addition, by applying the 2PP technique, structural properties of the cellular microenvironment can also be mimicked. Furthermore, in vitro degradation assays indicated that the enzymatic degradation capability of gelatin is preserved for the methacrylamide-modified derivative. An in depth morphological analysis of the 2PP-fabricated scaffolds demonstrated that the parameters of the CAD model are reproduced with great precision, including the ridge-like surface topography on the order of 1.5 μm. The developed scaffolds showed an excellent stability in culture medium. In a final part of the present work, the suitability of the developed scaffolds for tissue engineering applications was verified. The results indicated that the applied materials are suitable to support porcine mesenchymal stem cell adhesion and subsequent proliferation. Upon applying osteogenic stimulation, the seeded cells differentiated into the anticipated lineage. Energy dispersive X-ray (EDX) analysis showed the induced calcification of the scaffolds. The results clearly indicate that 2PP is capable of manufacturing precisely constructed 3D tissue engineering scaffolds using photosensitive polymers as starting material. PMID:21366287

  14. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds.

    PubMed

    Sun, Kai; Li, Ruixin; Jiang, Wenxue; Sun, Yufu; Li, Hui

    2016-09-01

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young's modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering.

  15. Fabrication of Cell Patches Using Biodegradable Scaffolds with a Hexagonal Array of Interconnected Pores (SHAIPs)

    PubMed Central

    Zhang, Yu Shrike; Yao, Junjie; Wang, Lihong V.; Xia, Younan

    2013-01-01

    Cell patches are widely used for healing injuries on the surfaces or interfaces of tissues such as those of epidermis and myocardium. Here we report a novel type of porous scaffolds made of poly(D,L-lactic-co-glycolic acid) for fabricating cell patches. The scaffolds have a single layer of spherical pores arranged in a unique hexagonal pattern and are therefore referred to as “scaffolds with a hexagonal array of interconnected pores (SHAIPs)”. SHAIPs contain both uniform pores and interconnecting windows that can facilitate the exchange of biomacromolecules, ensure homogeneous cell seeding, and promote cell migration. As a proof-of-concept demonstration, we have created skeletal muscle patches with a thickness of approximately 150 μm using SHAIPs. The myoblasts seeded in the scaffolds maintained high viability and were able to differentiate into multi-nucleated myotubes. Moreover, neovasculature could efficiently develop into the patches upon subcutaneous implantation in vivo. PMID:24443593

  16. Fabrication and development of artificial osteochondral constructs based on cancellous bone/hydrogel hybrid scaffold.

    PubMed

    Song, Kedong; Li, Liying; Yan, Xinyu; Zhang, Yu; Li, Ruipeng; Wang, Yiwei; Wang, Ling; Wang, Hong; Liu, Tianqing

    2016-06-01

    Using tissue engineering techniques, an artificial osteochondral construct was successfully fabricated to treat large osteochondral defects. In this study, porcine cancellous bones and chitosan/gelatin hydrogel scaffolds were used as substitutes to mimic bone and cartilage, respectively. The porosity and distribution of pore size in porcine bone was measured and the degradation ratio and swelling ratio for chitosan/gelatin hydrogel scaffolds was also determined in vitro. Surface morphology was analyzed with the scanning electron microscope (SEM). The physicochemical properties and the composition were tested by using an infrared instrument. A double layer composite scaffold was constructed via seeding adipose-derived stem cells (ADSCs) induced to chondrocytes and osteoblasts, followed by inoculation in cancellous bones and hydrogel scaffolds. Cell proliferation was assessed through Dead/Live staining and cellular activity was analyzed with IpWin5 software. Cell growth, adhesion and formation of extracellular matrix in composite scaffolds blank cancellous bones or hydrogel scaffolds were also analyzed. SEM analysis revealed a super porous internal structure of cancellous bone scaffolds and pore size was measured at an average of 410 ± 59 μm while porosity was recorded at 70.6 ± 1.7 %. In the hydrogel scaffold, the average pore size was measured at 117 ± 21 μm and the porosity and swelling rate were recorded at 83.4 ± 0.8 % and 362.0 ± 2.4 %, respectively. Furthermore, the remaining hydrogel weighed 80.76 ± 1.6 % of the original dry weight after hydration in PBS for 6 weeks. In summary, the cancellous bone and hydrogel composite scaffold is a promising biomaterial which shows an essential physical performance and strength with excellent osteochondral tissue interaction in situ. ADSCs are a suitable cell source for osteochondral composite reconstruction. Moreover, the bi-layered scaffold significantly enhanced cell proliferation compared to the cells seeded on

  17. Fabrication and development of artificial osteochondral constructs based on cancellous bone/hydrogel hybrid scaffold.

    PubMed

    Song, Kedong; Li, Liying; Yan, Xinyu; Zhang, Yu; Li, Ruipeng; Wang, Yiwei; Wang, Ling; Wang, Hong; Liu, Tianqing

    2016-06-01

    Using tissue engineering techniques, an artificial osteochondral construct was successfully fabricated to treat large osteochondral defects. In this study, porcine cancellous bones and chitosan/gelatin hydrogel scaffolds were used as substitutes to mimic bone and cartilage, respectively. The porosity and distribution of pore size in porcine bone was measured and the degradation ratio and swelling ratio for chitosan/gelatin hydrogel scaffolds was also determined in vitro. Surface morphology was analyzed with the scanning electron microscope (SEM). The physicochemical properties and the composition were tested by using an infrared instrument. A double layer composite scaffold was constructed via seeding adipose-derived stem cells (ADSCs) induced to chondrocytes and osteoblasts, followed by inoculation in cancellous bones and hydrogel scaffolds. Cell proliferation was assessed through Dead/Live staining and cellular activity was analyzed with IpWin5 software. Cell growth, adhesion and formation of extracellular matrix in composite scaffolds blank cancellous bones or hydrogel scaffolds were also analyzed. SEM analysis revealed a super porous internal structure of cancellous bone scaffolds and pore size was measured at an average of 410 ± 59 μm while porosity was recorded at 70.6 ± 1.7 %. In the hydrogel scaffold, the average pore size was measured at 117 ± 21 μm and the porosity and swelling rate were recorded at 83.4 ± 0.8 % and 362.0 ± 2.4 %, respectively. Furthermore, the remaining hydrogel weighed 80.76 ± 1.6 % of the original dry weight after hydration in PBS for 6 weeks. In summary, the cancellous bone and hydrogel composite scaffold is a promising biomaterial which shows an essential physical performance and strength with excellent osteochondral tissue interaction in situ. ADSCs are a suitable cell source for osteochondral composite reconstruction. Moreover, the bi-layered scaffold significantly enhanced cell proliferation compared to the cells seeded on

  18. A synergistic approach to the design, fabrication and evaluation of 3D printed micro and nano featured scaffolds for vascularized bone tissue repair

    NASA Astrophysics Data System (ADS)

    Holmes, Benjamin; Bulusu, Kartik; Plesniak, Michael; Zhang, Lijie Grace

    2016-02-01

    3D bioprinting has begun to show great promise in advancing the development of functional tissue/organ replacements. However, to realize the true potential of 3D bioprinted tissues for clinical use requires the fabrication of an interconnected and effective vascular network. Solving this challenge is critical, as human tissue relies on an adequate network of blood vessels to transport oxygen, nutrients, other chemicals, biological factors and waste, in and out of the tissue. Here, we have successfully designed and printed a series of novel 3D bone scaffolds with both bone formation supporting structures and highly interconnected 3D microvascular mimicking channels, for efficient and enhanced osteogenic bone regeneration as well as vascular cell growth. Using a chemical functionalization process, we have conjugated our samples with nano hydroxyapatite (nHA), for the creation of novel micro and nano featured devices for vascularized bone growth. We evaluated our scaffolds with mechanical testing, hydrodynamic measurements and in vitro human mesenchymal stem cell (hMSC) adhesion (4 h), proliferation (1, 3 and 5 d) and osteogenic differentiation (1, 2 and 3 weeks). These tests confirmed bone-like physical properties and vascular-like flow profiles, as well as demonstrated enhanced hMSC adhesion, proliferation and osteogenic differentiation. Additional in vitro experiments with human umbilical vein endothelial cells also demonstrated improved vascular cell growth, migration and organization on micro-nano featured scaffolds.

  19. A synergistic approach to the design, fabrication and evaluation of 3D printed micro and nano featured scaffolds for vascularized bone tissue repair

    PubMed Central

    Holmes, Benjamin; Bulusu, Kartik; Plesniak, Michael; Zhang, Lijie Grace

    2016-01-01

    3D bioprinting has begun to show great promise in advancing the development of functional tissue/organ replacements. However, to realize the true potential of 3D bioprinted tissues for clinical use requires the fabrication of an interconnected and effective vascular network. Solving this challenge is critical, as human tissue relies on an adequate network of blood vessels to transport oxygen, nutrients, other chemicals, biological factors and waste, in and out of the tissue. Here, we have successfully designed and printed a series of novel 3D bone scaffolds with both bone formation supporting structures and highly interconnected 3D microvascular mimicking channels, for efficient and enhanced osteogenic bone regeneration as well as vascular cell growth. Using a chemical functionalization process, we have conjugated our samples with nano hydroxyapatite (nHA), for the creation of novel micro and nano featured devices for vascularized bone growth. We evaluated our scaffolds with mechanical testing, hydrodynamic measurements and in vitro human mesenchymal stem cell (hMSC) adhesion (4 h), proliferation (1, 3 and 5 d) and osteogenic differentiation (1, 2 and 3 weeks). These tests confirmed bone-like physical properties and vascular-like flow profiles, as well as demonstrated enhanced hMSC adhesion, proliferation and osteogenic differentiation. Additional in vitro experiments with human umbilical vein endothelial cells also demonstrated improved vascular cell growth, migration and organization on micro-nano featured scaffolds. PMID:26758780

  20. A synergistic approach to the design, fabrication and evaluation of 3D printed micro and nano featured scaffolds for vascularized bone tissue repair.

    PubMed

    Holmes, Benjamin; Bulusu, Kartik; Plesniak, Michael; Zhang, Lijie Grace

    2016-02-12

    3D bioprinting has begun to show great promise in advancing the development of functional tissue/organ replacements. However, to realize the true potential of 3D bioprinted tissues for clinical use requires the fabrication of an interconnected and effective vascular network. Solving this challenge is critical, as human tissue relies on an adequate network of blood vessels to transport oxygen, nutrients, other chemicals, biological factors and waste, in and out of the tissue. Here, we have successfully designed and printed a series of novel 3D bone scaffolds with both bone formation supporting structures and highly interconnected 3D microvascular mimicking channels, for efficient and enhanced osteogenic bone regeneration as well as vascular cell growth. Using a chemical functionalization process, we have conjugated our samples with nano hydroxyapatite (nHA), for the creation of novel micro and nano featured devices for vascularized bone growth. We evaluated our scaffolds with mechanical testing, hydrodynamic measurements and in vitro human mesenchymal stem cell (hMSC) adhesion (4 h), proliferation (1, 3 and 5 d) and osteogenic differentiation (1, 2 and 3 weeks). These tests confirmed bone-like physical properties and vascular-like flow profiles, as well as demonstrated enhanced hMSC adhesion, proliferation and osteogenic differentiation. Additional in vitro experiments with human umbilical vein endothelial cells also demonstrated improved vascular cell growth, migration and organization on micro-nano featured scaffolds.

  1. Fabrication of a customized bone scaffold using a homemade medical 3D printer for comminuted fractures

    NASA Astrophysics Data System (ADS)

    Yoon, Do-Kun; Jung, Joo-Young; Shin, Han-Back; Kim, Moo-Sub; Choe, Bo-Young; Kim, Sunmi; Suh, Tae Suk; Lee, Keum Sil; Xing, Lei

    2016-09-01

    The purpose of this study was to show a 3D printed reconstruction model of a bone destroyed by a comminuted fracture. After a thoracic limb of a cow with a comminuted fracture was scanned by using computed tomography, a scaffold was designed by using a 3D modeling tool for its reconstruction and fabricated by using a homemade medical 3D printer. The homemade medical 3D printer was designed for medical use. In order to reconstruct the geometry of the destroyed bone, we use the geometry of a similar section (reference geometry) of normal bone in the 3D modeling process. The missing part between the destroyed ridge and the reference geometry was filled with an effective space by using a manual interpolation. Inexpensive materials and free software were used to construct the medical 3D printer system. The fabrication of the scaffold progressed according to the design of reconstructed bone by using this medical 3D printer. The material of the scaffold was biodegradable material, and could be transplanted into the human body. The fabricated scaffold was correctly inserted into the fractured bone in place of the destroyed portion, with good agreement. According to physical stress test results, the performance of printing resolution was 0.1 mm. The average geometrical error of the scaffold was below 0.3 mm. The reconstructed bone by using the fabricated scaffold was able to support the weight of the human body. No process used to obtain the result was complex or required many resources. The methods and results in this study show several possible clinical applications in fields such as orthopedics or oncology without a need to purchase high-price instruments for 3D printing.

  2. Development of an indirect stereolithography technology for scaffold fabrication with a wide range of biomaterial selectivity.

    PubMed

    Kang, Hyun-Wook; Cho, Dong-Woo

    2012-09-01

    Tissue engineering, which is the study of generating biological substitutes to restore or replace tissues or organs, has the potential to meet current needs for organ transplantation and medical interventions. Various approaches have been attempted to apply three-dimensional (3D) solid freeform fabrication technologies to tissue engineering for scaffold fabrication. Among these, the stereolithography (SL) technology not only has the highest resolution, but also offers quick fabrication. However, a lack of suitable biomaterials is a barrier to applying the SL technology to tissue engineering. In this study, an indirect SL method that combines the SL technology and a sacrificial molding process was developed to address this challenge. A sacrificial mold with an inverse porous shape was fabricated from an alkali-soluble photopolymer by the SL technology. A sacrificial molding process was then developed for scaffold construction using a variety of biomaterials. The results indicated a wide range of biomaterial selectivity and a high resolution. Achievable minimum pore and strut sizes were as large as 50 and 65 μm, respectively. This technology can also be used to fabricate three-dimensional organ shapes, and combined with traditional fabrication methods to construct a new type of scaffold with a dual-pore size. Cytotoxicity tests, as well as nuclear magnetic resonance and gel permeation chromatography analyses, showed that this technology has great potential for tissue engineering applications.

  3. Development of an Indirect Stereolithography Technology for Scaffold Fabrication with a Wide Range of Biomaterial Selectivity

    PubMed Central

    Kang, Hyun-Wook

    2012-01-01

    Tissue engineering, which is the study of generating biological substitutes to restore or replace tissues or organs, has the potential to meet current needs for organ transplantation and medical interventions. Various approaches have been attempted to apply three-dimensional (3D) solid freeform fabrication technologies to tissue engineering for scaffold fabrication. Among these, the stereolithography (SL) technology not only has the highest resolution, but also offers quick fabrication. However, a lack of suitable biomaterials is a barrier to applying the SL technology to tissue engineering. In this study, an indirect SL method that combines the SL technology and a sacrificial molding process was developed to address this challenge. A sacrificial mold with an inverse porous shape was fabricated from an alkali-soluble photopolymer by the SL technology. A sacrificial molding process was then developed for scaffold construction using a variety of biomaterials. The results indicated a wide range of biomaterial selectivity and a high resolution. Achievable minimum pore and strut sizes were as large as 50 and 65 μm, respectively. This technology can also be used to fabricate three-dimensional organ shapes, and combined with traditional fabrication methods to construct a new type of scaffold with a dual-pore size. Cytotoxicity tests, as well as nuclear magnetic resonance and gel permeation chromatography analyses, showed that this technology has great potential for tissue engineering applications. PMID:22443315

  4. On-Demand Guided Bone Regeneration with Microbial Protection of Ornamented SPU Scaffold with Bismuth-Doped Single Crystalline Hydroxyapatite: Augmentation and Cartilage Formation.

    PubMed

    Selvakumar, M; Srivastava, Priyanka; Pawar, Harpreet Singh; Francis, Nimmy K; Das, Bodhisatwa; Sathishkumar, G; Subramanian, Bhuvaneshwaran; Jaganathan, Saravana Kumar; George, Gibin; Anandhan, S; Dhara, Santanu; Nando, Golok B; Chattopadhyay, Santanu

    2016-02-17

    Guided bone regeneration (GBR) scaffolds are futile in many clinical applications due to infection problems. In this work, we fabricated GBR with an anti-infective scaffold by ornamenting 2D single crystalline bismuth-doped nanohydroxyapatite (Bi-nHA) rods onto segmented polyurethane (SPU). Bi-nHA with high aspect ratio was prepared without any templates. Subsequently, it was introduced into an unprecedented synthesized SPU matrix based on dual soft segments (PCL-b-PDMS) of poly(ε-caprolactone) (PCL) and poly(dimethylsiloxane) (PDMS), by an in situ technique followed by electrospinning to fabricate scaffolds. For comparison, undoped pristine nHA rods were also ornamented into it. The enzymatic ring-opening polymerization technique was adapted to synthesize soft segments of PCL-b-PDMS copolymers of SPU. Structure elucidation of the synthesized polymers is done by nuclear magnetic resonance spectroscopy. Sparingly, Bi-nHA ornamented scaffolds exhibit tremendous improvement (155%) in the mechanical properties with excellent antimicrobial activity against various human pathogens. After confirmation of high osteoconductivity, improved biodegradation, and excellent biocompatibility against osteoblast cells (in vitro), the scaffolds were implanted in rabbits by subcutaneous and intraosseous (tibial) sites. Various histological sections reveal the signatures of early cartilage formation, endochondral ossification, and rapid bone healing at 4 weeks of the critical defects filled with ornamented scaffold compared to SPU scaffold. This implies osteogenic potential and ability to provide an adequate biomimetic microenvironment for mineralization for GBR of the scaffolds. Organ toxicity studies further confirm that no tissue architecture abnormalities were observed in hepatic, cardiac, and renal tissue sections. This finding manifests the feasibility of fabricating a mechanically adequate nanofibrous SPU scaffold by a biomimetic strategy and the advantages of Bi

  5. Fabrication of biodegradable elastomeric scaffolds with sub-micron morphologies

    PubMed Central

    Stankus, John J.; Guan, Jianjun; Wagner, William R.

    2010-01-01

    The native extracellular matrix (ECM) of elastic tissues is strong and flexible and supports cell adhesion and enzymatic matrix remodeling. In an attempt to convey these ECM properties to a synthetic scaffold appropriate for soft tissue engineering applications, a biodegradable, elastomeric poly(ester urethane)urea (PEUU) was combined with type I collagen at various ratios (2.5, 5, 10, 20, 50, 60, 70, 80, and 90 wt% collagen) and electrospun to construct elastic matrices. Randomly orientated fibers in the electrospun matrices ranged in diameter from 100–900 nm, dependent on initial polymer concentration. Picrosirius red staining of matrices and CD spectroscopy of released collagen confirmed collagen incorporation and preservation of collagen structure at the higher collagen mass fractions. Matrices were strong and distensible possessing strengths of 2–13 MPa with breaking strains of 160–280% even with low PEUU content. Collagen incorporation significantly enhanced smooth muscle cell adhesion onto electrospun scaffolds. An approach has been demonstrated that mimics elastic extracellular matrices by using a synthetic component to provide mechanical function together with a biomacromolecule, collagen. Such matrices may find application in engineering soft tissue. PMID:15307165

  6. Extrusion based rapid prototyping technique: an advanced platform for tissue engineering scaffold fabrication.

    PubMed

    Hoque, M Enamul; Chuan, Y Leng; Pashby, Ian

    2012-02-01

    Advances in scaffold design and fabrication technology have brought the tissue engineering field stepping into a new era. Conventional techniques used to develop scaffolds inherit limitations, such as lack of control over the pore morphology and architecture as well as reproducibility. Rapid prototyping (RP) technology, a layer-by-layer additive approach offers a unique opportunity to build complex 3D architectures overcoming those limitations that could ultimately be tailored to cater for patient-specific applications. Using RP methods, researchers have been able to customize scaffolds to mimic the biomechanical properties (in terms of structural integrity, strength, and microenvironment) of the organ or tissue to be repaired/replaced quite closely. This article provides intensive description on various extrusion based scaffold fabrication techniques and review their potential utility for TE applications. The extrusion-based technique extrudes the molten polymer as a thin filament through a nozzle onto a platform layer-by-layer and thus building 3D scaffold. The technique allows full control over pore architecture and dimension in the x- and y- planes. However, the pore height in z-direction is predetermined by the extruding nozzle diameter rather than the technique itself. This review attempts to assess the current state and future prospects of this technology.

  7. Fabrication and characterization of interconnected porous biodegradable poly(ε-caprolactone) load bearing scaffolds.

    PubMed

    Allaf, Rula M; Rivero, Iris V

    2011-08-01

    In this study, poly(ε-caprolactone) (PCL)/poly(ethylene oxide) (PEO) (50:50 wt%) immiscible blend was used as a model system to investigate the feasibility of a novel solventless fabrication approach that combines cryomilling, compression molding and porogen leaching techniques to prepare interconnected porous scaffolds for tissue engineering. PCL was cryomilled with PEO to form blend powders. Compression molding was used to consolidate and anneal the cryomilled powders. Selective dissolution of the PEO with water resulted in interconnected porous scaffolds. Sodium chloride salt (NaCl) was subsequently added to cryomilled powder to increase the porosity of scaffolds. The prepared scaffolds had homogeneous pore structures, a porosity of ~50% which was increased by mixing salt with the blend (~70% for 60% wt% NaCl), and a compressive modulus and strength (ε = 10%) of 60 and 2.8 MPa, respectively. The results of the study confirm that this novel approach offers a viable alternative to fabricate scaffolds.

  8. Fabrication of Aligned Nanofiber Polymer Yarn Networks for Anisotropic Soft Tissue Scaffolds.

    PubMed

    Wu, Shaohua; Duan, Bin; Liu, Penghong; Zhang, Caidan; Qin, Xiaohong; Butcher, Jonathan T

    2016-07-01

    Nanofibrous scaffolds with defined architectures and anisotropic mechanical properties are attractive for many tissue engineering and regenerative medicine applications. Here, a novel electrospinning system is developed and implemented to fabricate continuous processable uniaxially aligned nanofiber yarns (UANY). UANY were processed into fibrous tissue scaffolds with defined anisotropic material properties using various textile-forming technologies, i.e., braiding, weaving, and knitting techniques. UANY braiding dramatically increased overall stiffness and strength compared to the same number of UANY unbraided. Human adipose derived stem cells (HADSC) cultured on UANY or woven and knitted 3D scaffolds aligned along local fiber direction and were >90% viable throughout 21 days. Importantly, UANY supported biochemical induction of HADSC differentiation toward smooth muscle and osteogenic lineages. Moreover, we integrated an anisotropic woven fiber mesh within a bioactive hydrogel to mimic the complex microstructure and mechanical behavior of valve tissues. Human aortic valve interstitial cells (HAVIC) and human aortic root smooth muscle cells (HASMC) were separately encapsulated within hydrogel/woven fabric composite scaffolds for generating scaffolds with anisotropic biomechanics and valve ECM like microenvironment for heart valve tissue engineering. UANY have great potential as building blocks for generating fiber-shaped tissues or tissue microstructures with complex architectures.

  9. A new method of fabricating a blend scaffold using an indirect three-dimensional printing technique.

    PubMed

    Jung, Jin Woo; Lee, Hyungseok; Hong, Jung Min; Park, Jeong Hun; Shim, Jung Hee; Choi, Tae Hyun; Cho, Dong-Woo

    2015-01-01

    Due to its simplicity and effectiveness, the physical blending of polymers is considered to be a practical strategy for developing a versatile scaffold having desirable mechanical and biochemical properties. In the present work, an indirect three-dimensional (i3D) printing technique was proposed to fabricate a 3D free-form scaffold using a blend of immiscible materials, such as polycaprolactone (PCL) and gelatin. The i3D printing technique includes 3D printing of a mold and a sacrificial molding process. PCL/chloroform and gelatin/water were physically mixed to prepare the blend solution, which was subsequently injected into the cavity of a 3D printed mold. After solvent removal and gelatin cross-linking, the mold was dissolved to obtain a PCL-gelatin (PG) scaffold, with a specific 3D structure. Scanning electron microscopy and Fourier transform infrared spectroscopy analysis indicated that PCL masses and gelatin fibers in the PG scaffold homogenously coexisted without chemical bonding. Compression tests confirmed that gelatin incorporation into the PCL enhanced its mechanical flexibility and softness, to the point of being suitable for soft-tissue engineering, as opposed to pure PCL. Human adipose-derived stem cells, cultured on a PG scaffold, exhibited enhanced in vitro chondrogenic differentiation and tissue formation, compared with those on a PCL scaffold. The i3D printing technique can be used to blend a variety of materials, facilitating 3D scaffold fabrication for specific tissue regeneration. Furthermore, this convenient and versatile technique may lead to wider application of 3D printing in tissue engineering. PMID:26525821

  10. A new method of fabricating a blend scaffold using an indirect three-dimensional printing technique.

    PubMed

    Jung, Jin Woo; Lee, Hyungseok; Hong, Jung Min; Park, Jeong Hun; Shim, Jung Hee; Choi, Tae Hyun; Cho, Dong-Woo

    2015-11-03

    Due to its simplicity and effectiveness, the physical blending of polymers is considered to be a practical strategy for developing a versatile scaffold having desirable mechanical and biochemical properties. In the present work, an indirect three-dimensional (i3D) printing technique was proposed to fabricate a 3D free-form scaffold using a blend of immiscible materials, such as polycaprolactone (PCL) and gelatin. The i3D printing technique includes 3D printing of a mold and a sacrificial molding process. PCL/chloroform and gelatin/water were physically mixed to prepare the blend solution, which was subsequently injected into the cavity of a 3D printed mold. After solvent removal and gelatin cross-linking, the mold was dissolved to obtain a PCL-gelatin (PG) scaffold, with a specific 3D structure. Scanning electron microscopy and Fourier transform infrared spectroscopy analysis indicated that PCL masses and gelatin fibers in the PG scaffold homogenously coexisted without chemical bonding. Compression tests confirmed that gelatin incorporation into the PCL enhanced its mechanical flexibility and softness, to the point of being suitable for soft-tissue engineering, as opposed to pure PCL. Human adipose-derived stem cells, cultured on a PG scaffold, exhibited enhanced in vitro chondrogenic differentiation and tissue formation, compared with those on a PCL scaffold. The i3D printing technique can be used to blend a variety of materials, facilitating 3D scaffold fabrication for specific tissue regeneration. Furthermore, this convenient and versatile technique may lead to wider application of 3D printing in tissue engineering.

  11. Fabrication of anatomically-shaped cartilage constructs using decellularized cartilage-derived matrix scaffolds.

    PubMed

    Rowland, Christopher R; Colucci, Lina A; Guilak, Farshid

    2016-06-01

    The native extracellular matrix of cartilage contains entrapped growth factors as well as tissue-specific epitopes for cell-matrix interactions, which make it a potentially attractive biomaterial for cartilage tissue engineering. A limitation to this approach is that the native cartilage extracellular matrix possesses a pore size of only a few nanometers, which inhibits cellular infiltration. Efforts to increase the pore size of cartilage-derived matrix (CDM) scaffolds dramatically attenuate their mechanical properties, which makes them susceptible to cell-mediated contraction. In previous studies, we have demonstrated that collagen crosslinking techniques are capable of preventing cell-mediated contraction in CDM disks. In the current study, we investigated the effects of CDM concentration and pore architecture on the ability of CDM scaffolds to resist cell-mediated contraction. Increasing CDM concentration significantly increased scaffold mechanical properties, which played an important role in preventing contraction, and only the highest CDM concentration (11% w/w) was able to retain the original scaffold dimensions. However, the increase in CDM concentration led to a concomitant decrease in porosity and pore size. Generating a temperature gradient during the freezing process resulted in unidirectional freezing, which aligned the formation of ice crystals during the freezing process and in turn produced aligned pores in CDM scaffolds. These aligned pores increased the pore size of CDM scaffolds at all CDM concentrations, and greatly facilitated infiltration by mesenchymal stem cells (MSCs). These methods were used to fabricate of anatomically-relevant CDM hemispheres. CDM hemispheres with aligned pores supported uniform MSC infiltration and matrix deposition. Furthermore, these CDM hemispheres retained their original architecture and did not contract, warp, curl, or splay throughout the entire 28-day culture period. These findings demonstrate that given the

  12. Fabrication of elastomeric scaffolds with curvilinear fibrous structures for heart valve leaflet engineering

    PubMed Central

    Hobson, Christopher M.; Amoroso, Nicholas J.; Amini, Rouzbeh; Ungchusri, Ethan; Hong, Yi; D’Amore, Antonio; Sacks, Michael S.; Wagner, William R.

    2015-01-01

    Native semi-lunar heart valves are composed of a dense fibrous network that generally follows a curvilinear path along the width of the leaflet. Recent models of engineered valve leaflets have predicted that such curvilinear fiber orientations would homogenize the strain field and reduce stress concentrations at the commissure. In the present work, a method was developed to reproduce this curvilinear fiber alignment in electrospun scaffolds by varying the geometry of the collecting mandrel. Elastomeric poly(ester urethane)urea was electrospun onto rotating conical mandrels of varying angles to produce fibrous scaffolds where the angle of fiber alignment varied linearly over scaffold length. By matching the radius of the conical mandrel to the radius of curvature for the native pulmonary valve, the electrospun constructs exhibited a curvilinear fiber structure similar to the native leaflet. Moreover, the constructs had local mechanical properties comparable to conventional scaffolds and native heart valves. In agreement with prior modeling results, it was found under quasi-static loading that curvilinear fiber microstructures reduced strain concentrations compared to scaffolds generated on a conventional cylindrical mandrels. Thus, this simple technique offers an attractive means for fabricating scaffolds where key microstructural features of the native leaflet are imitated for heart valve tissue engineering. PMID:25771748

  13. Fabrication of elastomeric scaffolds with curvilinear fibrous structures for heart valve leaflet engineering.

    PubMed

    Hobson, Christopher M; Amoroso, Nicholas J; Amini, Rouzbeh; Ungchusri, Ethan; Hong, Yi; D'Amore, Antonio; Sacks, Michael S; Wagner, William R

    2015-09-01

    Native semi-lunar heart valves are composed of a dense fibrous network that generally follows a curvilinear path along the width of the leaflet. Recent models of engineered valve leaflets have predicted that such curvilinear fiber orientations would homogenize the strain field and reduce stress concentrations at the commissure. In the present work, a method was developed to reproduce this curvilinear fiber alignment in electrospun scaffolds by varying the geometry of the collecting mandrel. Elastomeric poly(ester urethane)urea was electrospun onto rotating conical mandrels of varying angles to produce fibrous scaffolds where the angle of fiber alignment varied linearly over scaffold length. By matching the radius of the conical mandrel to the radius of curvature for the native pulmonary valve, the electrospun constructs exhibited a curvilinear fiber structure similar to the native leaflet. Moreover, the constructs had local mechanical properties comparable to conventional scaffolds and native heart valves. In agreement with prior modeling results, it was found under quasi-static loading that curvilinear fiber microstructures reduced strain concentrations compared to scaffolds generated on a conventional cylindrical mandrels. Thus, this simple technique offers an attractive means for fabricating scaffolds where key microstructural features of the native leaflet are imitated for heart valve tissue engineering.

  14. Fabrication of PLLA/β-TCP nanocomposite scaffolds with hierarchical porosity for bone tissue engineering.

    PubMed

    Lou, Tao; Wang, Xuejun; Song, Guojun; Gu, Zheng; Yang, Zhen

    2014-08-01

    Polymer and ceramic composite scaffolds play a crucial role in bone tissue engineering. In an attempt to mimic the architecture of natural extracellular matrix (ECM), poly(l-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) nanocomposite scaffolds with a hierarchical pore structure were fabricated by combining thermal induced phase separation and salt leaching techniques. The nanocomposite scaffold consisted of a nanofibrous PLLA matrix with a highly interconnected, high porosity (>93%) hierarchical pore structure with pore diameters ranging from 500nm to 300μm and a homogeneously distributed β-TCP nanoparticle phase. The nanofibrous PLLA matrix had a fiber diameter of 70-300nm. The nanocomposite scaffolds possess three levels of hierarchical structure: (1) porosity; (2) nanofibrous PLLA struts comprising the pore walls; and (3) β-TCP nanoparticle phase. The β-TCP nanoparticle phase improved the mechanical properties and bioactivity of the PLLA matrix. The nanocomposite scaffolds supported MG-63 osteoblast proliferation, penetration, and ECM deposition, indicating the potential of PLLA/β-TCP nanocomposite scaffolds with hierarchical porosity for bone tissue engineering applications.

  15. Sphere-shaped nano-hydroxyapatite/chitosan/gelatin 3D porous scaffolds increase proliferation and osteogenic differentiation of human induced pluripotent stem cells from gingival fibroblasts.

    PubMed

    Ji, Jun; Tong, Xin; Huang, Xiaofeng; Wang, Tiancong; Lin, Zitong; Cao, Yazhou; Zhang, Junfeng; Dong, Lei; Qin, Haiyan; Hu, Qingang

    2015-08-01

    Hydroxyapatite (HA) is an important component of human bone and bone tissue engineering scaffolds. A plethora of bone tissue engineering scaffolds have been synthesized so far, including nano-HA/chitosan/gelatin (nHA/CG) scaffolds; and for seeding cells, stem cells, especially induced pluripotent stem cells (iPSCs), have been a promising cell source for bone tissue engineering recently. However, the influence of different HA nano-particle morphologies on the osteogenic differentiation of human iPSCs (hiPSCs) from human gingival fibroblasts (hGFs) is unknown. The purpose of this study was to investigate the osteogenic differentiation of hiPSCs from hGFs seeded on nHA/CG scaffolds with 2 shapes (rod and sphere) of nHA particles. Firstly, hGFs isolated from discarded normal gingival tissues were reprogrammed into hiPSCs. Secondly, hiPSCs were seeded on rod-like nHA/CG (rod-nHA/CG) and sphere-shaped nHA/CG (sphere-nHA/CG) scaffolds respectively and then cell/scaffold complexes were cultured in vitro. Scanning electron microscope, hematoxyline and eosin (HE) staining, Masson's staining, and quantitative real-time polymerase chain reaction techniques were used to examine hiPSC morphology, proliferation, and differentiation on rod-nHA/CG and sphere-nHA/CG scaffolds. Finally, hiPSCs composited with 2 kinds of nHA/CG were transplanted in vivo in a subcutaneous implantation model for 12 weeks; pure scaffolds were also transplanted as a blank control. HE, Masson's, and immunohistochemistry staining were applied to detect new bone regeneration ability. The results showed that sphere-nHA/CG significantly increased hiPSCs from hGF proliferation and osteogenic differentiation in vitro. hiPSCs and sphere-nHA/CG composities generated large bone, whereas hiPSCs and rod-nHA/CG composities produced tiny bone in vivo. Moreover, pure scaffolds without cells almost produced no bone. In conclusion, our work provided a potential innovative bone tissue engineering approach using

  16. Microstereolithography-Based Fabrication of Anatomically Shaped Beta-Tricalcium Phosphate Scaffolds for Bone Tissue Engineering.

    PubMed

    Du, Dajiang; Asaoka, Teruo; Shinohara, Makoto; Kageyama, Tomonori; Ushida, Takashi; Furukawa, Katsuko Sakai

    2015-01-01

    Porous ceramic scaffolds with shapes matching the bone defects may result in more efficient grafting and healing than the ones with simple geometries. Using computer-assisted microstereolithography (MSTL), we have developed a novel gelcasting indirect MSTL technology and successfully fabricated two scaffolds according to CT images of rabbit femur. Negative resin molds with outer 3D dimensions conforming to the femur and an internal structure consisting of stacked meshes with uniform interconnecting struts, 0.5 mm in diameter, were fabricated by MSTL. The second mold type was designed for cortical bone formation. A ceramic slurry of beta-tricalcium phosphate (β-TCP) with room temperature vulcanization (RTV) silicone as binder was cast into the molds. After the RTV silicone was completely cured, the composite was sintered at 1500°C for 5 h. Both gross anatomical shape and the interpenetrating internal network were preserved after sintering. Even cortical structure could be introduced into the customized scaffolds, which resulted in enhanced strength. Biocompatibility was confirmed by vital staining of rabbit bone marrow mesenchymal stromal cells cultured on the customized scaffolds for 5 days. This fabrication method could be useful for constructing bone substitutes specifically designed according to local anatomical defects. PMID:26504839

  17. Microstereolithography-Based Fabrication of Anatomically Shaped Beta-Tricalcium Phosphate Scaffolds for Bone Tissue Engineering

    PubMed Central

    Du, Dajiang; Asaoka, Teruo; Shinohara, Makoto; Kageyama, Tomonori; Ushida, Takashi; Furukawa, Katsuko Sakai

    2015-01-01

    Porous ceramic scaffolds with shapes matching the bone defects may result in more efficient grafting and healing than the ones with simple geometries. Using computer-assisted microstereolithography (MSTL), we have developed a novel gelcasting indirect MSTL technology and successfully fabricated two scaffolds according to CT images of rabbit femur. Negative resin molds with outer 3D dimensions conforming to the femur and an internal structure consisting of stacked meshes with uniform interconnecting struts, 0.5 mm in diameter, were fabricated by MSTL. The second mold type was designed for cortical bone formation. A ceramic slurry of beta-tricalcium phosphate (β-TCP) with room temperature vulcanization (RTV) silicone as binder was cast into the molds. After the RTV silicone was completely cured, the composite was sintered at 1500°C for 5 h. Both gross anatomical shape and the interpenetrating internal network were preserved after sintering. Even cortical structure could be introduced into the customized scaffolds, which resulted in enhanced strength. Biocompatibility was confirmed by vital staining of rabbit bone marrow mesenchymal stromal cells cultured on the customized scaffolds for 5 days. This fabrication method could be useful for constructing bone substitutes specifically designed according to local anatomical defects. PMID:26504839

  18. Microstereolithography-Based Fabrication of Anatomically Shaped Beta-Tricalcium Phosphate Scaffolds for Bone Tissue Engineering.

    PubMed

    Du, Dajiang; Asaoka, Teruo; Shinohara, Makoto; Kageyama, Tomonori; Ushida, Takashi; Furukawa, Katsuko Sakai

    2015-01-01

    Porous ceramic scaffolds with shapes matching the bone defects may result in more efficient grafting and healing than the ones with simple geometries. Using computer-assisted microstereolithography (MSTL), we have developed a novel gelcasting indirect MSTL technology and successfully fabricated two scaffolds according to CT images of rabbit femur. Negative resin molds with outer 3D dimensions conforming to the femur and an internal structure consisting of stacked meshes with uniform interconnecting struts, 0.5 mm in diameter, were fabricated by MSTL. The second mold type was designed for cortical bone formation. A ceramic slurry of beta-tricalcium phosphate (β-TCP) with room temperature vulcanization (RTV) silicone as binder was cast into the molds. After the RTV silicone was completely cured, the composite was sintered at 1500°C for 5 h. Both gross anatomical shape and the interpenetrating internal network were preserved after sintering. Even cortical structure could be introduced into the customized scaffolds, which resulted in enhanced strength. Biocompatibility was confirmed by vital staining of rabbit bone marrow mesenchymal stromal cells cultured on the customized scaffolds for 5 days. This fabrication method could be useful for constructing bone substitutes specifically designed according to local anatomical defects.

  19. Scanning Small- and Wide-Angle X-ray Scattering Microscopy Selectively Probes HA Content in Gelatin/Hydroxyapatite Scaffolds for Osteochondral Defect Repair.

    PubMed

    Altamura, Davide; Pastore, Stella G; Raucci, Maria G; Siliqi, Dritan; De Pascalis, Fabio; Nacucchi, Michele; Ambrosio, Luigi; Giannini, Cinzia

    2016-04-01

    This study is aimed at investigating the structure of a scaffold made of bovine gelatin and hydroxyapatite for bone tissue engineering purposes. In particular, the detailed characterization of such a material has a great relevance because of its application in the healing process of the osteochondral defect that consists of a damage of cartilage and injury of the adjacent subchondral bone, significantly compromising millions of patient's quality of life. Two different techniques exploiting X-ray radiation, with table-top setups, are used: microtomography (micro-CT) and microdiffraction. Micro-CT characterizes the microstructure in the three dimensions at the micrometer scale spatial resolution, whereas microdiffraction provides combined structural/morphological information at the atomic and nanoscale, in two dimensional microscopy images with a hundred micrometer spatial resolution. The combination of these two techniques allowed an appropriate structural characterization for the purpose of validating the engineering approach used for the realization of the hydroxyapatite gradient across the scaffold, with properties close to the natural model. PMID:27020229

  20. A novel gellan-PVA nanofibrous scaffold for skin tissue regeneration: Fabrication and characterization.

    PubMed

    Vashisth, Priya; Nikhil, Kumar; Roy, Partha; Pruthi, Parul A; Singh, Rajesh P; Pruthi, Vikas

    2016-01-20

    In this investigation, we have introduced novel electrospun gellan based nanofibers as a hydrophilic scaffolding material for skin tissue regeneration. These nanofibers were fabricated using a blend mixture of gellan with polyvinyl alcohol (PVA). PVA reduced the repulsive force of resulting solution and lead to formation of uniform fibers with improved nanostructure. Field emission scanning electron microscopy (FESEM) confirmed the average diameter of nanofibers down to 50 nm. The infrared spectra (IR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis evaluated the crosslinking, thermal stability and highly crystalline nature of gellan-PVA nanofibers, respectively. Furthermore, the cell culture studies using human dermal fibroblast (3T3L1) cells established that these gellan based nanofibrous scaffold could induce improved cell adhesion and enhanced cell growth than conventionally proposed gellan based hydrogels and dry films. Importantly, the nanofibrous scaffold are biodegradable and could be potentially used as a temporary substrate/or biomedical graft to induce skin tissue regeneration.

  1. A biomimetic multilayer nanofiber fabric fabricated by electrospinning and textile technology from polylactic acid and Tussah silk fibroin as a scaffold for bone tissue engineering.

    PubMed

    Shao, Weili; He, Jianxin; Han, Qiming; Sang, Feng; Wang, Qian; Chen, Li; Cui, Shizhong; Ding, Bin

    2016-10-01

    To engineer bone tissue, a scaffold with good biological properties should be provided to approximate the hierarchical structure of collagen fibrils in natural bone. In this study, we fabricated a novel scaffold consisting of multilayer nanofiber fabrics (MLNFFs) by weaving nanofiber yarns of polylactic acid (PLA) and Tussah silk fibroin (TSF). The yarns were fabricated by electrospinning, and we found that spinnability, as well as the mechanical properties of the resulting scaffold, was determined by the ratio between polylactic acid and Tussah silk fibroin. In particular, a 9:1 mixture can be spun continuously into nanofiber yarns with narrow diameter distribution and good mechanical properties. Accordingly, woven scaffolds based on this mixture had excellent mechanical properties, with Young's modulus 417.65MPa and tensile strength 180.36MPa. For nonwoven scaffolds fabricated from the same materials, the Young's modulus and tensile strength were 2- and 4-fold lower, respectively. Woven scaffolds also supported adhesion and proliferation of mouse mesenchymal stem cells, and promoted biomineralization via alkaline phosphatase and mineral deposition. Finally, the scaffolds significantly enhanced the formation of new bone in damaged femoral condyle in rabbits. Thus, the scaffolds are potentially suitable for bone tissue engineering because of biomimetic architecture, excellent mechanical properties, and good biocompatibility.

  2. A biomimetic multilayer nanofiber fabric fabricated by electrospinning and textile technology from polylactic acid and Tussah silk fibroin as a scaffold for bone tissue engineering.

    PubMed

    Shao, Weili; He, Jianxin; Han, Qiming; Sang, Feng; Wang, Qian; Chen, Li; Cui, Shizhong; Ding, Bin

    2016-10-01

    To engineer bone tissue, a scaffold with good biological properties should be provided to approximate the hierarchical structure of collagen fibrils in natural bone. In this study, we fabricated a novel scaffold consisting of multilayer nanofiber fabrics (MLNFFs) by weaving nanofiber yarns of polylactic acid (PLA) and Tussah silk fibroin (TSF). The yarns were fabricated by electrospinning, and we found that spinnability, as well as the mechanical properties of the resulting scaffold, was determined by the ratio between polylactic acid and Tussah silk fibroin. In particular, a 9:1 mixture can be spun continuously into nanofiber yarns with narrow diameter distribution and good mechanical properties. Accordingly, woven scaffolds based on this mixture had excellent mechanical properties, with Young's modulus 417.65MPa and tensile strength 180.36MPa. For nonwoven scaffolds fabricated from the same materials, the Young's modulus and tensile strength were 2- and 4-fold lower, respectively. Woven scaffolds also supported adhesion and proliferation of mouse mesenchymal stem cells, and promoted biomineralization via alkaline phosphatase and mineral deposition. Finally, the scaffolds significantly enhanced the formation of new bone in damaged femoral condyle in rabbits. Thus, the scaffolds are potentially suitable for bone tissue engineering because of biomimetic architecture, excellent mechanical properties, and good biocompatibility. PMID:27287159

  3. Functionalized scaffolds to enhance tissue regeneration

    PubMed Central

    Guo, Baolin; Lei, Bo; Li, Peng; Ma, Peter X.

    2015-01-01

    Tissue engineering scaffolds play a vital role in regenerative medicine. It not only provides a temporary 3-dimensional support during tissue repair, but also regulates the cell behavior, such as cell adhesion, proliferation and differentiation. In this review, we summarize the development and trends of functional scaffolding biomaterials including electrically conducting hydrogels and nanocomposites of hydroxyapatite (HA) and bioactive glasses (BGs) with various biodegradable polymers. Furthermore, the progress on the fabrication of biomimetic nanofibrous scaffolds from conducting polymers and composites of HA and BG via electrospinning, deposition and thermally induced phase separation is discussed. Moreover, bioactive molecules and surface properties of scaffolds are very important during tissue repair. Bioactive molecule-releasing scaffolds and antimicrobial surface coatings for biomedical implants and scaffolds are also reviewed. PMID:25844177

  4. Fabrication and in vitro biological evaluation of photopolymerisable hydroxyapatite hydrogel composites for bone regeneration.

    PubMed

    Killion, John A; Geever, Luke M; Devine, Declan M; Higginbotham, Clement L

    2014-04-01

    The aim of this study was to improve the bioactive and compressive properties of photopolymerisable polyethylene glycol hydrogels with the incorporation of hydroxyapatite at different loadings. The synthesis of pure hydroxyapatite was verified through Fourier transform infrared spectroscopy (FTIR) analysis by the complete reaction of all constituents. The formation of a bioactive layer of the hydrogel based composites was confirmed through the formation of carbonate hydroxyapatite after soaking the samples in simulated body fluid. The incorporation of hydroxyapatite into the system resulted in an increase in Young's modulus from 4.36 to 12.73 MPa and an increase in the stress at limit value from 1.20 to 4.42 MPa. This was due to the hydroxyapatite absorbing the compressive load, the polymer matrix distributing the load, a reduction in swelling and the presence of physical crosslinking between both components. Drug dissolution testing showed that the release rate of a drug from the hydrogels was dependent on the molecular weight of the polymer and the type of drug used.

  5. Fabrication of 3D porous silk scaffolds by particulate (salt/sucrose) leaching for bone tissue reconstruction.

    PubMed

    Park, Hyun Jung; Lee, Ok Joo; Lee, Min Chae; Moon, Bo Mi; Ju, Hyung Woo; Lee, Jung min; Kim, Jung-Ho; Kim, Dong Wook; Park, Chan Hum

    2015-01-01

    Silk fibroin is a biomaterial being actively studied in the field of bone tissue engineering. In this study, we aimed to select the best strategy for bone reconstruction on scaffolds by changing various conditions. We compared the characteristics of each scaffold via structural analysis using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), the swelling ratio, water uptake, porosity, compressive strength, cell infiltration and cell viability (CCK-8). The scaffolds had high porosity with good inter pore connectivity and showed high compressive strength and modulus. In addition, to confirm bone reconstruction, animal studies were conducted in which samples were implanted in rat calvaria and investigated by micro-CT scans. In conclusion, the presented study indicates that using sucrose produces scaffolds showing better pore interconnectivity and cell infiltration than scaffolds made by using a salt process. In addition, in vivo experiments showed that hydroxyapatite accelerates bone reconstruction on implanted scaffolds. Accordingly, our scaffold will be expected to have a useful application in bone reconstruction.

  6. Functionalized carbon nanotube reinforced scaffolds for bone regenerative engineering: fabrication, in vitro and in vivo evaluation.

    PubMed

    Mikael, Paiyz E; Amini, Ami R; Basu, Joysurya; Josefina Arellano-Jimenez, M; Laurencin, Cato T; Sanders, Mary M; Barry Carter, C; Nukavarapu, Syam P

    2014-06-01

    Designing biodegradable scaffolds with bone-compatible mechanical properties has been a significant challenge in the field of bone tissue engineering and regenerative engineering. The objective of this work is to improve the polymeric scaffold's mechanical strength by compositing it with mechanically superior carbon nanotubes. Poly(lactide-co-glycolide) (PLGA) microsphere scaffolds exhibit mechanical properties in the range of human cancellous bone. On the other hand, carbon nanotubes have outstanding mechanical properties. The aim of this study is to improve further the mechanical strength of PLGA scaffolds such that they may be applicable for a wide range of load-bearing repair and regeneration applications. We have formed composite microspheres of PLGA containing pristine and modified (with hydroxyl (OH), carboxylic acid (COOH)) multi-walled carbon nanotubes (MWCNTs), and fabricated them into three-dimensional porous scaffolds. Results show that by adding only 3% MWCNTs, the compressive strength and modulus was significantly increased (35 MPa, 510.99 MPa) compared to pure PLGA scaffolds (19 MPa and 166.38 MPa). Scanning electron microscopy images showed excellent cell adhesion and proliferation. In vitro studies exhibited good cell viability, proliferation and mineralization. The in vivo study, however, indicated differences in inflammatory response throughout the 12 weeks of implantation, with OH-modified MWCNTs having the least response, followed by unmodified and COOH-modified exhibiting a more pronounced response. Overall, our results show that PLGA scaffolds containing water-dispersible MWCNTs are mechanically stronger and display good cellular and tissue compatibility, and hence are potential candidates for load-bearing bone tissue engineering. PMID:24687391

  7. Indirect three-dimensional printing: A method for fabricating polyurethane-urea based cardiac scaffolds.

    PubMed

    Hernández-Córdova, R; Mathew, D A; Balint, R; Carrillo-Escalante, H J; Cervantes-Uc, J M; Hidalgo-Bastida, L A; Hernández-Sánchez, F

    2016-08-01

    Biomaterial scaffolds are a key part of cardiac tissue engineering therapies. The group has recently synthesized a novel polycaprolactone based polyurethane-urea copolymer that showed improved mechanical properties compared with its previously published counterparts. The aim of this study was to explore whether indirect three-dimensional (3D) printing could provide a means to fabricate this novel, biodegradable polymer into a scaffold suitable for cardiac tissue engineering. Indirect 3D printing was carried out through printing water dissolvable poly(vinyl alcohol) porogens in three different sizes based on a wood-stack model, into which a polyurethane-urea solution was pressure injected. The porogens were removed, leading to soft polyurethane-urea scaffolds with regular tubular pores. The scaffolds were characterized for their compressive and tensile mechanical behavior; and their degradation was monitored for 12 months under simulated physiological conditions. Their compatibility with cardiac myocytes and performance in novel cardiac engineering-related techniques, such as aggregate seeding and bi-directional perfusion, was also assessed. The scaffolds were found to have mechanical properties similar to cardiac tissue, and good biocompatibility with cardiac myocytes. Furthermore, the incorporated cells preserved their phenotype with no signs of de-differentiation. The constructs worked well in perfusion experiments, showing enhanced seeding efficiency. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1912-1921, 2016. PMID:26991636

  8. Creating tissues from textiles: scalable nonwoven manufacturing techniques for fabrication of tissue engineering scaffolds.

    PubMed

    Tuin, S A; Pourdeyhimi, B; Loboa, E G

    2016-02-23

    Electrospun nonwovens have been used extensively for tissue engineering applications due to their inherent similarities with respect to fibre size and morphology to that of native extracellular matrix (ECM). However, fabrication of large scaffold constructs is time consuming, may require harsh organic solvents, and often results in mechanical properties inferior to the tissue being treated. In order to translate nonwoven based tissue engineering scaffold strategies to clinical use, a high throughput, repeatable, scalable, and economic manufacturing process is needed. We suggest that nonwoven industry standard high throughput manufacturing techniques (meltblowing, spunbond, and carding) can meet this need. In this study, meltblown, spunbond and carded poly(lactic acid) (PLA) nonwovens were evaluated as tissue engineering scaffolds using human adipose derived stem cells (hASC) and compared to electrospun nonwovens. Scaffolds were seeded with hASC and viability, proliferation, and differentiation were evaluated over the course of 3 weeks. We found that nonwovens manufactured via these industry standard, commercially relevant manufacturing techniques were capable of supporting hASC attachment, proliferation, and both adipogenic and osteogenic differentiation of hASC, making them promising candidates for commercialization and translation of nonwoven scaffold based tissue engineering strategies.

  9. Creating tissues from textiles: scalable nonwoven manufacturing techniques for fabrication of tissue engineering scaffolds.

    PubMed

    Tuin, S A; Pourdeyhimi, B; Loboa, E G

    2016-02-01

    Electrospun nonwovens have been used extensively for tissue engineering applications due to their inherent similarities with respect to fibre size and morphology to that of native extracellular matrix (ECM). However, fabrication of large scaffold constructs is time consuming, may require harsh organic solvents, and often results in mechanical properties inferior to the tissue being treated. In order to translate nonwoven based tissue engineering scaffold strategies to clinical use, a high throughput, repeatable, scalable, and economic manufacturing process is needed. We suggest that nonwoven industry standard high throughput manufacturing techniques (meltblowing, spunbond, and carding) can meet this need. In this study, meltblown, spunbond and carded poly(lactic acid) (PLA) nonwovens were evaluated as tissue engineering scaffolds using human adipose derived stem cells (hASC) and compared to electrospun nonwovens. Scaffolds were seeded with hASC and viability, proliferation, and differentiation were evaluated over the course of 3 weeks. We found that nonwovens manufactured via these industry standard, commercially relevant manufacturing techniques were capable of supporting hASC attachment, proliferation, and both adipogenic and osteogenic differentiation of hASC, making them promising candidates for commercialization and translation of nonwoven scaffold based tissue engineering strategies. PMID:26908485

  10. Fabrication of alumina porous scaffolds with aligned oriented pores for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Sarhadi, Fatemeh; Shafiee Afarani, Mahdi; Mohebbi-Kalhori, Davod; Shayesteh, Masoud

    2016-04-01

    In the present study, porous alumina scaffolds with specific orientation and anisotropic properties are fabricated for application in bone tissue repair. The scaffolds with double shape pores, tubular oriented and isotropic rounded pores, were prepared using alumina and silica as starting materials by the slip casting route. Milled polyurethane foam and silk fibers were applied as replica materials as well. The effect of fiber types and diameter and number of fibers on the microstructure and pore size was studied. Moreover, different characteristics such as porosity, density, orientation, flexural strength and compressive strength of the samples were investigated. Results showed that various fibers with different diameters and numbers led to forming the pores with different pore sizes, microstructure and consequently changes in the physical and mechanical properties. In addition, the simultaneous presence of fibers and particles led to more porous scaffolds. The oriented tiny micro-tube and rounded pores were observed in all porous ceramic scaffolds. Mechanical testing showed an anisotropy in the mechanical behaviors such that higher strengths were observed in the oriented pore direction than that of transverse. With increasing the number and diameter of silk fibers, the scaffolds with a high porosity up to 68 vol% and proper flexural strength were obtained.

  11. Application of visible light-based projection stereolithography for live cell-scaffold fabrication with designed architecture.

    PubMed

    Lin, Hang; Zhang, Dongning; Alexander, Peter G; Yang, Guang; Tan, Jian; Cheng, Anthony Wai-Ming; Tuan, Rocky S

    2013-01-01

    One-step scaffold fabrication with live cell incorporation is a highly desirable technology for tissue engineering and regeneration. Projection stereolithography (PSL) represents a promising method owing to its fine resolution, high fabrication speed and computer-aided design (CAD) capabilities. However, the majority of current protocols utilize water-insoluble photoinitiators that are incompatible with live cell-fabrication, and ultraviolet (UV) light that is damaging to the cellular DNA. We report here the development of a visible light-based PSL system (VL-PSL), using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as the initiator and polyethylene glycol diacrylate (PEGDA) as the monomer, to produce hydrogel scaffolds with specific shapes and internal architectures. Furthermore, live human adipose-derived stem cells (hADSCs) were suspended in PEGDA/LAP solution during the PSL process, and were successfully incorporated within the fabricated hydrogel scaffolds. hADSCs in PEG scaffolds showed high viability (>90%) for up to 7 days after fabrication as revealed by Live/Dead staining. Scaffolds with porous internal architecture retained higher cell viability and activity than solid scaffolds, likely due to increased oxygen and nutrients exchange into the interior of the scaffolds. The VL-PSL should be applicable as an efficient and effective tissue engineering technology for point-of-care tissue repair in the clinic.

  12. Application of Visible Light-based Projection Stereolithography for Live Cell-Scaffold Fabrication with Designed Architecture

    PubMed Central

    Lin, Hang; Zhang, Dongning; Alexander, Peter G.; Yang, Guang; Tan, Jian; Cheng, Anthony Wai-Ming; Tuan, Rocky S.

    2013-01-01

    One-step scaffold fabrication with live cell incorporation is a highly desirable technology for tissue engineering and regeneration. Projection stereolithography (PSL) represents a promising method owing to its fine resolution, high fabrication speed and computer-aided design (CAD) capabilities. However, the majority of current protocols utilize water-insoluble photoinitiators that are incompatible with live cell-fabrication, and ultraviolet (UV) light that is damaging to the cellular DNA. We report here the development of a visible light-based PSL system (VL-PSL), using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as the initiator and polyethylene glycol diacrylate (PEGDA) as the monomer, to produce hydrogel scaffolds with specific shapes and internal architectures. Furthermore, live human adipose-derived stem cells (hADSCs) were suspended in PEGDA/LAP solution during the PSL process, and were successfully incorporated within the fabricated hydrogel scaffolds. hADSCs in PEG scaffolds showed high viability (>90%) for up to 7 days after fabrication as revealed by Live/Dead staining. Scaffolds with porous internal architecture retained higher cell viability and activity than solid scaffolds, likely due to increased oxygen and nutrients exchange into the interior of the scaffolds. The VL-PSL should be applicable as an efficient and effective tissue engineering technology for point-of-care tissue repair in clinic. PMID:23092861

  13. Mechanical properties of bioactive glass (13-93) scaffolds fabricated by robotic deposition for structural bone repair.

    PubMed

    Liu, Xin; Rahaman, Mohamed N; Hilmas, Gregory E; Bal, B Sonny

    2013-06-01

    There is a need to develop synthetic scaffolds to repair large defects in load-bearing bones. Bioactive glasses have attractive properties as a scaffold material for bone repair, but data on their mechanical properties are limited. The objective of the present study was to comprehensively evaluate the mechanical properties of strong porous scaffolds of silicate 13-93 bioactive glass fabricated by robocasting. As-fabricated scaffolds with a grid-like microstructure (porosity 47%, filament diameter 330μm, pore width 300μm) were tested in compressive and flexural loading to determine their strength, elastic modulus, Weibull modulus, fatigue resistance, and fracture toughness. Scaffolds were also tested in compression after they were immersed in simulated body fluid (SBF) in vitro or implanted in a rat subcutaneous model in vivo. As fabricated, the scaffolds had a strength of 86±9MPa, elastic modulus of 13±2GPa, and a Weibull modulus of 12 when tested in compression. In flexural loading the strength, elastic modulus, and Weibull modulus were 11±3MPa, 13±2GPa, and 6, respectively. In compression, the as-fabricated scaffolds had a mean fatigue life of ∼10(6) cycles when tested in air at room temperature or in phosphate-buffered saline at 37°C under cyclic stresses of 1-10 or 2-20MPa. The compressive strength of the scaffolds decreased markedly during the first 2weeks of immersion in SBF or implantation in vivo, but more slowly thereafter. The brittle mechanical response of the scaffolds in vitro changed to an elasto-plastic response after implantation for longer than 2-4weeks in vivo. In addition to providing critically needed data for designing bioactive glass scaffolds, the results are promising for the application of these strong porous scaffolds in loaded bone repair.

  14. Mechanical properties of bioactive glass (13-93) scaffolds fabricated by robotic deposition for structural bone repair

    PubMed Central

    Liu, Xin; Rahaman, Mohamed N.; Hilmas, Gregory E.; Bal, B. Sonny

    2013-01-01

    There is a need to develop synthetic scaffolds for repairing large defects in load-bearing bones. Bioactive glasses have attractive properties as a scaffold material for bone repair, but data on their mechanical properties are limited. The objective of the present study was to comprehensively evaluate the mechanical properties of strong porous scaffolds of silicate 13-93 bioactive glass fabricated by robocasting. As-fabricated scaffolds with a grid-like microstructure (porosity = 47%; filament diameter = 330 μm; pore width = 300) were tested in compressive and flexural loading to determine their strength, elastic modulus, Weibull modulus, fatigue resistance, and fracture toughness. Scaffolds were also tested in compression after they were immersed in simulated body fluid (SBF) in vitro or implanted in a rat subcutaneous model in vivo. As fabricated, the scaffolds had a strength = 86 ± 9 MPa, elastic modulus = 13 ± 2 GPa, and a Weibull modulus = 12 when tested in compression. In flexural loading, the strength, elastic modulus, and Weibull modulus were 11 ± 3 MPa, 13 ± 2 GPa, and 6, respectively. In compression, the as-fabricated scaffolds had a mean fatigue life of ~106 cycles when tested in air at room temperature or in phosphate-buffered saline at 37 °C under cyclic stresses of 1–10 MPa or 2–20 MPa. The compressive strength of the scaffolds decreased markedly during the first 2 weeks of immersion in SBF or implantation in vivo, but more slowly thereafter. The brittle mechanical response of the scaffolds in vitro changed to an elasto-plastic response after implantation for longer than 2–4 weeks in vivo. In addition to providing critically needed data for designing bioactive glass scaffolds, the results are promising for the application of these strong porous scaffolds in loaded bone repair. PMID:23438862

  15. Fabrication of macroporous cement scaffolds using PEG particles: In vitro evaluation with induced pluripotent stem cell-derived mesenchymal progenitors.

    PubMed

    Sladkova, Martina; Palmer, Michael; Öhman, Caroline; Alhaddad, Rawan Jaragh; Esmael, Asmaa; Engqvist, Håkan; de Peppo, Giuseppe Maria

    2016-12-01

    Calcium phosphate cements (CPCs) have been extensively used in reconstructive dentistry and orthopedics, but it is only recently that CPCs have been combined with stem cells to engineer biological substitutes with enhanced healing potential. In the present study, macroporous CPC scaffolds with defined composition were fabricated using an easily reproduced synthesis method, with minimal fabrication and processing steps. Scaffold pore size and porosity, essential for cell infiltration and tissue ingrowth, were tuned by varying the content and size of polyethylene glycol (PEG) particles, resulting in 9 groups with different architectural features. The scaffolds were characterized for chemical composition, porosity and mechanical properties, then tested in vitro with human mesenchymal progenitors derived from induced pluripotent stem cells (iPSC-MPs). Biomimetic decellularized bone scaffolds were used as reference material in this study. Our manufacturing process resulted in the formation of macroporous monetite scaffolds with no residual traces of PEG. The size and content of PEG particles was found to affect scaffold porosity, and thus mechanical properties. Irrespective of pore size and porosity, the CPC scaffolds fabricated in this study supported adhesion and viability of human iPSC-MPs similarly to decellularized bone scaffolds. However, the architectural features of the scaffolds were found to affect the expression of bone specific genes, suggesting that specific scaffold groups could be more suitable to direct human iPSC-MPs in vitro toward an osteoblastic phenotype. Our simplistic fabrication method allows rapid, inexpensive and reproducible construction of macroporous CPC scaffolds with tunable architecture for potential use in dental and orthopedic applications. PMID:27612757

  16. Fabrication of scalable tissue engineering scaffolds with dual-pore microarchitecture by combining 3D printing and particle leaching.

    PubMed

    Mohanty, Soumyaranjan; Sanger, Kuldeep; Heiskanen, Arto; Trifol, Jon; Szabo, Peter; Dufva, Marin; Emnéus, Jenny; Wolff, Anders

    2016-04-01

    Limitations in controlling scaffold architecture using traditional fabrication techniques are a problem when constructing engineered tissues/organs. Recently, integration of two pore architectures to generate dual-pore scaffolds with tailored physical properties has attracted wide attention in tissue engineering community. Such scaffolds features primary structured pores which can efficiently enhance nutrient/oxygen supply to the surrounding, in combination with secondary random pores, which give high surface area for cell adhesion and proliferation. Here, we present a new technique to fabricate dual-pore scaffolds for various tissue engineering applications where 3D printing of poly(vinyl alcohol) (PVA) mould is combined with salt leaching process. In this technique the sacrificial PVA mould, determining the structured pore architecture, was filled with salt crystals to define the random pore regions of the scaffold. After crosslinking the casted polymer the combined PVA-salt mould was dissolved in water. The technique has advantages over previously reported ones, such as automated assembly of the sacrificial mould, and precise control over pore architecture/dimensions by 3D printing parameters. In this study, polydimethylsiloxane and biodegradable poly(ϵ-caprolactone) were used for fabrication. However, we show that this technique is also suitable for other biocompatible/biodegradable polymers. Various physical and mechanical properties of the dual-pore scaffolds were compared with control scaffolds with either only structured or only random pores, fabricated using previously reported methods. The fabricated dual-pore scaffolds supported high cell density, due to the random pores, in combination with uniform cell distribution throughout the scaffold, and higher cell proliferation and viability due to efficient nutrient/oxygen transport through the structured pores. In conclusion, the described fabrication technique is rapid, inexpensive, scalable, and compatible

  17. Fabrication of scalable tissue engineering scaffolds with dual-pore microarchitecture by combining 3D printing and particle leaching.

    PubMed

    Mohanty, Soumyaranjan; Sanger, Kuldeep; Heiskanen, Arto; Trifol, Jon; Szabo, Peter; Dufva, Marin; Emnéus, Jenny; Wolff, Anders

    2016-04-01

    Limitations in controlling scaffold architecture using traditional fabrication techniques are a problem when constructing engineered tissues/organs. Recently, integration of two pore architectures to generate dual-pore scaffolds with tailored physical properties has attracted wide attention in tissue engineering community. Such scaffolds features primary structured pores which can efficiently enhance nutrient/oxygen supply to the surrounding, in combination with secondary random pores, which give high surface area for cell adhesion and proliferation. Here, we present a new technique to fabricate dual-pore scaffolds for various tissue engineering applications where 3D printing of poly(vinyl alcohol) (PVA) mould is combined with salt leaching process. In this technique the sacrificial PVA mould, determining the structured pore architecture, was filled with salt crystals to define the random pore regions of the scaffold. After crosslinking the casted polymer the combined PVA-salt mould was dissolved in water. The technique has advantages over previously reported ones, such as automated assembly of the sacrificial mould, and precise control over pore architecture/dimensions by 3D printing parameters. In this study, polydimethylsiloxane and biodegradable poly(ϵ-caprolactone) were used for fabrication. However, we show that this technique is also suitable for other biocompatible/biodegradable polymers. Various physical and mechanical properties of the dual-pore scaffolds were compared with control scaffolds with either only structured or only random pores, fabricated using previously reported methods. The fabricated dual-pore scaffolds supported high cell density, due to the random pores, in combination with uniform cell distribution throughout the scaffold, and higher cell proliferation and viability due to efficient nutrient/oxygen transport through the structured pores. In conclusion, the described fabrication technique is rapid, inexpensive, scalable, and compatible

  18. Fabrication of dual-pore scaffolds using SLUP (salt leaching using powder) and WNM (wire-network molding) techniques.

    PubMed

    Cho, Yong Sang; Hong, Myoung Wha; Kim, So-Youn; Lee, Seung-Jae; Lee, Jun Hee; Kim, Young Yul; Cho, Young-Sam

    2014-12-01

    In this study, a novel technique was proposed to fabricate dual-pore scaffolds combining both SLUP (salt leaching using powder) and WNM (wire-network molding) techniques. This technique has several advantages: solvent-free, no limit on the use of thermoplastic polymers as a raw material, and easiness of fabricating scaffolds with dual-scale pores that are interconnected randomized small pores. To fabricate dual-pore scaffolds, PCL and NaCl powders were mixed at a certain ratio. Subsequently, needles were inserted into a designed mold, and the mixture was filled into the mold thereafter. Subsequently, after the mold was pressurized, the mold was heated to melt the PCL powders. The PCL/NaCl structure and needles were separated from the mold. The structure was sonicated to leach-out the NaCl particles and was dried. Consequently, the remaining PCL structure became the dual-pore scaffold. To compare the characteristics of dual-pore scaffolds, control scaffolds, which are 3D plotter and SLUP scaffolds were fabricated. PMID:25491863

  19. Fabrication of silk fibroin blended P(LLA-CL) nanofibrous scaffolds for tissue engineering.

    PubMed

    Zhang, Kuihua; Wang, Hongsheng; Huang, Chen; Su, Yan; Mo, Xiumei; Ikada, Yoshito

    2010-06-01

    Electrospinning using natural proteins and synthetic polymers offers an attractive technique for producing fibrous scaffolds with potential for tissue regeneration and repair. Nanofibrous scaffolds of silk fibroin (SF) and poly(L-lactic acid-co-epsilon-caprolactone) (P(LLA-CL)) blends were fabricated using 1,1,1,3,3,3-hexafluoro-2-propanol as a solvent via electrospinning. The average nanofibrous diameter increased with increasing polymer concentration and decreasing the blend ratio of SF to P(LLA-CL). Characterizations of XPS and (13)C NMR clarified the presence of SF on their surfaces and no obvious chemical bond reaction between SF with P(LLA-CL) and SF in SF/P(LLA-CL) nanofibers was present in a random coil conformation, SF conformation transformed from random coil to beta-sheet when treated with water vapor. Whereas water contact angle measurements conformed greater hydrophilicity than P(LLA-CL). Both the tensile strength and elongation at break increased with the content increasing of P(LLA-CL). Cell viability studies with pig iliac endothelial cells demonstrated that SF/P(LLA-CL) blended nanofibrous scaffolds significantly promoted cell growth in comparison with P(LLA-CL), especially when the weight ratio of SF to P(LLA-CL) was 25:75. These results suggested that SF/P(LLA-CL) blended nanofibrous scaffolds might be potential candidates for vascular tissue engineering.

  20. A three-dimensional hierarchical collagen scaffold fabricated by a combined solid freeform fabrication (SFF) and electrospinning process to enhance mesenchymal stem cell (MSC) proliferation

    NASA Astrophysics Data System (ADS)

    Ahn, SeungHyun; Koh, Young Ho; Kim, GeunHyung

    2010-06-01

    Collagen has the advantage of being very similar to macromolecular substances that can be recognized and metabolized in the biological environment. Although the natural material has superior property for this purpose, its use to fabricate reproducible and pore-structure-controlled 3D structures, which are designed to allow the entry of sufficient cells and the easy diffusion of nutrients, has been limited due to its low processability. Here, we propose a hybrid technology that combines a cryogenic plotting system with an electrospinning process. Using this technique, an easily pore-size-controllable hierarchical 3D scaffold consisting of micro-sized highly porous collagen strands and micro/nano-sized collagen fibers was fabricated. The pore structure of the collagen scaffold was controlled by the collagen micro/nanofibers, which were layered in the scaffold. The hierarchical scaffolds were characterized with respect to initial cell attachment and proliferation of bone marrow-derived mesenchymal stem cells within the scaffolds. The hierarchical scaffold exhibited incredibly enhanced initial cell attachment and cell compactness between pores of the plotted scaffold relative to the normally designed 3D collagen scaffold.

  1. HA/nylon 6,6 porous scaffolds fabricated by salt-leaching/solvent casting technique: effect of nano-sized filler content on scaffold properties.

    PubMed

    Mehrabanian, Mehran; Nasr-Esfahani, Mojtaba

    2011-01-01

    Nanohydroxyapatite (n-HA)/nylon 6,6 composite scaffolds were produced by means of the salt-leaching/solvent casting technique. NaCl with a distinct range size was used with the aim of optimizing the pore network. Composite powders with different n-HA contents (40%, 60%) for scaffold fabrication were synthesized and tested. The composite scaffolds thus obtained were characterized for their microstructure, mechanical stability and strength, and bioactivity. The microstructure of the composite scaffolds possessed a well-developed interconnected porosity with approximate optimal pore size ranging from 200 to 500 μm, ideal for bone regeneration and vascularization. The mechanical properties of the composite scaffolds were evaluated by compressive strength and modulus tests, and the results confirmed their similarity to cortical bone. To characterize bioactivity, the composite scaffolds were immersed in simulated body fluid for different lengths of time and results monitored by scanning electron microscopy and energy dispersive X-ray microanalysis to determine formation of an apatite layer on the scaffold surface.

  2. Chitosan-g-lactide copolymers for fabrication of 3D scaffolds for tissue engineering

    NASA Astrophysics Data System (ADS)

    Demina, T. S.; Zaytseva-Zotova, D. S.; Timashev, P. S.; Bagratashvili, V. N.; Bardakova, K. N.; Sevrin, Ch; Svidchenko, E. A.; Surin, N. M.; Markvicheva, E. A.; Grandfils, Ch; Akopova, T. A.

    2015-07-01

    Chitosan-g-oligo (L, D-lactide) copolymers were synthesized and assessed to fabricate a number of 3D scaffolds using a variety of technologies such as oil/water emulsion evaporation technique, freeze-drying and two-photon photopolymerization. Solid-state copolymerization method allowed us to graft up to 160 wt-% of oligolactide onto chitosan backbone via chitosan amino group acetylation with substitution degree reaching up to 0.41. Grafting of hydrophobic oligolactide side chains with polymerization degree up to 10 results in chitosan amphiphilic properties. The synthesized chitosan-g-lactide copolymers were used to design 3D scaffolds for tissue engineering such as spherical microparticles and macroporous hydrogels.

  3. Fabrication of three-dimensional porous scaffold based on collagen fiber and bioglass for bone tissue engineering.

    PubMed

    Long, Teng; Yang, Jun; Shi, Shan-Shan; Guo, Ya-Ping; Ke, Qin-Fei; Zhu, Zhen-An

    2015-10-01

    An ideal scaffold for bone tissue engineering should have interconnected porous structure, good biocompatibility, and mechanical properties well-matched with natural bones. Collagen is the key component in the extracellular matrix (ECM) of natural bones, and plays an important role in bone regeneration. The biological activity of collagen has promoted it to be an advantageous biomaterial for bone tissue engineering; however, the mechanical properties of these scaffolds are insufficient and the porous structures are not stable in the wet state. An effective strategy to solve this problem is to fabricate a hybrid scaffold of biologically derived and synthetic material, which have the necessary bioactivity and mechanical stability needed for bone synthesis. In this work, a three-dimensional macroporous bone scaffold based on collagen (CO) fiber and bioglass (BG) is fabricated by a slurry-dipping technique, and its relevant mechanical and biological properties are evaluated. The CO/BG scaffold is interconnected with a porosity of 81 ± 4.6% and pore size of 40-200 μm. Compared with CO scaffold, water absorption value of CO/BG scaffold decreases greatly from 889% to 52%, which significantly alleviates the swelling behavior of collagen and improves the stability of scaffold structure. The CO/BG scaffold has a compression strength of 5.8 ± 1.6 MPa and an elastic modulus of 0.35 ± 0.01 Gpa, which are well-matched with the mechanical properties of trabecular bones. In vitro cell assays demonstrate that the CO/BG scaffold has good biocompatibility to facilitate the spreading and proliferation of human bone marrow stromal cells. Hence, the CO/BG scaffold is promising for bone tissue engineering application.

  4. The development, fabrication, and material characterization of polypropylene composites reinforced with carbon nanofiber and hydroxyapatite nanorod hybrid fillers

    PubMed Central

    Liao, Cheng Zhu; Wong, Hoi Man; Yeung, Kelvin Wai Kwok; Tjong, Sie Chin

    2014-01-01

    This study focuses on the design, fabrication, microstructural and property characterization, and biocompatibility evaluation of polypropylene (PP) reinforced with carbon nanofiber (CNF) and hydroxyapatite nanorod (HANR) fillers. The purpose is to develop advanced PP/CNF–HANR hybrids with good mechanical behavior, thermal stability, and excellent biocompatibility for use as craniofacial implants in orthopedics. Several material-examination techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, tensile tests, and impact measurement are used to characterize the microstructural, mechanical, and thermal properties of the hybrids. Furthermore, osteoblastic cell cultivation and colorimetric assay are also employed for assessing their viability on the composites. The CNF and HANR filler hybridization yields an improvement in Young’s modulus, impact strength, thermal stability, and biocompatibility of PP. The PP/2% CNF–20% HANR hybrid composite is found to exhibit the highest elastic modulus, tensile strength, thermal stability, and biocompatibility. PMID:24648729

  5. 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.

  6. 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

  7. MicroRNA-26a-modified adipose-derived stem cells incorporated with a porous hydroxyapatite scaffold improve the repair of bone defects

    PubMed Central

    WANG, ZHENLIN; ZHANG, DAWEI; HU, ZHIQIANG; CHENG, JIWEI; ZHUO, CHUANMENG; FANG, XIANCONG; XING, YONGMING

    2015-01-01

    Tissue-engineered bone substitutes are frequently used to repair bone defects. Adipose-derived stem cells (ASCs) are a promising source of cells for repairing bone tissue, however, insufficient osteogenic potency remains the main obstacle for their application. The present study aimed to enhance the osteogenic potency of ASCs by transfection of microRNA (miR)-26a, a novel osteogenic and angiogenic promoting miRNA. An inverted fluorescence microscope was used to observe transfection efficiency, while a scanning electron microscope was used to detect morphological alterations. Cell proliferation was monitored continuously for 7 days using a Cell Counting kit-8 assay. Osteogenic differentiation was determined by reverse transcription quantitative polymerase chain reaction, alkaline phosphatase (ALP) staining, collagen secretion and extracellular matrix (ECM) mineralization. ASCs were incorporated with a porous hydroxyapatite (HA) scaffold to create a novel tissue-engineered bone substitute and inserted into the critical tibia defect of rats. New bone formation was evaluated by hematoxylin and eosin and Masson's trichrome staining. The results demonstrated that miR-26a was successfully delivered into the cytoplasm, while the morphology and proliferation of ASCs were not significantly altered. Osteogenic-associated genes were markedly upregulated and ALP production, collagen secretion and ECM mineralization were all increased following transfection of miR-26a. Histological evaluation demonstrated that the modified cells accompanied with a porous HA scaffold markedly promoted new bone formation within the defective area. In conclusion, miR-26a transfection significantly improved the osteogenic potency of ASCs suggesting that modified ASCs incorporated with a HA scaffold may be used as a potential bone substitute. PMID:25997460

  8. Transplantation of human placenta-derived mesenchymal stem cells in a silk fibroin/hydroxyapatite scaffold improves bone repair in rabbits.

    PubMed

    Jin, Jun; Wang, Jun; Huang, Jian; Huang, Fang; Fu, Jianhong; Yang, Xinjing; Miao, Zongning

    2014-11-01

    The main requirements for successful tissue engineering of the bone are non-immunogenic cells with osteogenic potential and a porous biodegradable scaffold. The purpose of this study is to evaluate the potential of a silk fibroin/hydroxyapatite (SF/HA) porous material as a delivery vehicle for human placenta-derived mesenchymal stem cells (PMSCs) in a rabbit radius defect model. In this study, we randomly assigned 16 healthy adult New Zealand rabbits into two groups, subjected to transplantation with either SF/HA and PMSCs (experimental group) or SF/HA alone (control group). To evaluate fracture healing, we assessed the extent of graft absorption, the quantity of newly formed bone, and re-canalization of the cavitas medullaris using radiographic and histological tools. We performed flow cytometric analysis to characterize PMSCs, and found that while they express CD90, CD105 and CD73, they stain negative for HLA-DR and the hematopoietic cell surface markers CD34 and CD45. When PMSCs were exposed to osteogenic induction medium, they secreted calcium crystals that were identified by von Kossa staining. Furthermore, when seeded on the surface of SF/HA scaffold, they actively secreted extracellular matrix components. Here, we show, through radiographic and histological analyses, that fracture healing in the experimental group is significantly improved over the control group. This strongly suggests that transplantation of human PMSCs grown in an SF/HA scaffold into injured radius segmental bone in rabbits, can markedly enhance tissue repair. Our finding provides evidence supporting the utility of human placenta as a potential source of stem cells for bone tissue engineering.

  9. Poly(propylene fumarate) bone tissue engineering scaffold fabrication using stereolithography: effects of resin formulations and laser parameters.

    PubMed

    Lee, Kee-Won; Wang, Shanfeng; Fox, Bradley C; Ritman, Erik L; Yaszemski, Michael J; Lu, Lichun

    2007-04-01

    Stereolithography using photo-cross-linkable polymeric biomaterials is an effective technique for fabricating highly complex three-dimensional (3D) scaffolds with controlled microstructures for tissue engineering applications. In this study, we have optimized the UV curable polymer solution composition and laser parameters for the stereolithography machine. Poly(propylene fumarate) (PPF) was used as the biomaterial, diethyl fumarate (DEF) was used as the solvent, and bisacrylphosphrine oxide (BAPO) was used as the photoinitiator. Three different weight ratios of PPF/DEF and BAPO contents were characterized by measuring the viscosities and thermal properties of the un-cross-linked solutions and the mechanical properties of the formed scaffolds. After optimizing the resin composition by satisfying both the viscosity limitation and the mechanical requirement, laser parameters such as critical exposure (Ec) and penetration depth (Dp) were determined from the working curve and the relationship between laser speed and energy by measuring the thickness of predesigned windows fabricated in stereolithography with different ranges of Ec and Dp. Three-dimensional scaffolds with various pore sizes, pore shapes, and porosities were designed in computer-aided design (CAD) software and were fabricated in stereolithography. The fabricated scaffolds were characterized by measuring external dimensions, porosities, mean pore sizes, and compressive moduli and were compared to the CAD models. Feature accuracy in the xy-plane was achieved and overcuring of the resin in z-axis was minimized. The stereolithographically fabricated scaffolds with controlled microstructures can be useful in diverse tissue engineering applications. PMID:17326677

  10. Poly(propylene fumarate) bone tissue engineering scaffold fabrication using stereolithography: effects of resin formulations and laser parameters.

    PubMed

    Lee, Kee-Won; Wang, Shanfeng; Fox, Bradley C; Ritman, Erik L; Yaszemski, Michael J; Lu, Lichun

    2007-04-01

    Stereolithography using photo-cross-linkable polymeric biomaterials is an effective technique for fabricating highly complex three-dimensional (3D) scaffolds with controlled microstructures for tissue engineering applications. In this study, we have optimized the UV curable polymer solution composition and laser parameters for the stereolithography machine. Poly(propylene fumarate) (PPF) was used as the biomaterial, diethyl fumarate (DEF) was used as the solvent, and bisacrylphosphrine oxide (BAPO) was used as the photoinitiator. Three different weight ratios of PPF/DEF and BAPO contents were characterized by measuring the viscosities and thermal properties of the un-cross-linked solutions and the mechanical properties of the formed scaffolds. After optimizing the resin composition by satisfying both the viscosity limitation and the mechanical requirement, laser parameters such as critical exposure (Ec) and penetration depth (Dp) were determined from the working curve and the relationship between laser speed and energy by measuring the thickness of predesigned windows fabricated in stereolithography with different ranges of Ec and Dp. Three-dimensional scaffolds with various pore sizes, pore shapes, and porosities were designed in computer-aided design (CAD) software and were fabricated in stereolithography. The fabricated scaffolds were characterized by measuring external dimensions, porosities, mean pore sizes, and compressive moduli and were compared to the CAD models. Feature accuracy in the xy-plane was achieved and overcuring of the resin in z-axis was minimized. The stereolithographically fabricated scaffolds with controlled microstructures can be useful in diverse tissue engineering applications.

  11. Effects of surfactants on the microstructure of porous ceramic scaffolds fabricated by foaming for bone tissue engineering

    SciTech Connect

    Wang Xi; Ruan Jianming; Chen Qiyuan

    2009-06-03

    A porous scaffold comprising a {beta}-tricalcium phosphate matrix and bioactive glass powders was fabricated by foaming method and the effects of surfactants as foaming agent on microstructure of scaffolds were investigated. Foaming capacity and foam stability of different surfactants in water firstly were carried out to evaluate their foam properties. The porous structure and pore size distribution of the scaffolds were systematically characterized by scanning electron microscopy (SEM) and an optical microscopy connected to an image analyzer. The results showed that the foam stability of surfactant has more remarkable influence on their microstructure such as pore shape, size and interconnectivity than the foaming ability of one. Porous scaffolds fabricated using nonionic surfactant Tween 80 with large foam stability exhibited higher open and total porosities, and fully interconnected porous structure with a pore size of 750-850 {mu}m.

  12. Additive manufacturing of wet-spun polymeric scaffolds for bone tissue engineering.

    PubMed

    Puppi, Dario; Mota, Carlos; Gazzarri, Matteo; Dinucci, Dinuccio; Gloria, Antonio; Myrzabekova, Mairam; Ambrosio, Luigi; Chiellini, Federica

    2012-12-01

    An Additive Manufacturing technique for the fabrication of three-dimensional polymeric scaffolds, based on wet-spinning of poly(ε-caprolactone) (PCL) or PCL/hydroxyapatite (HA) solutions, was developed. The processing conditions to fabricate scaffolds with a layer-by-layer approach were optimized by studying their influence on fibres morphology and alignment. Two different scaffold architectures were designed and fabricated by tuning inter-fibre distance and fibres staggering. The developed scaffolds showed good reproducibility of the internal architecture characterized by highly porous, aligned fibres with an average diameter in the range 200-250 μm. Mechanical characterization showed that the architecture and HA loading influenced the scaffold compressive modulus and strength. Cell culture experiments employing MC3T3-E1 preosteoblast cell line showed good cell adhesion, proliferation, alkaline phosphatase activity and bone mineralization on the developed scaffolds.

  13. Ferroelectric polymer scaffolds based on a copolymer of tetrafluoroethylene with vinylidene fluoride: fabrication and properties.

    PubMed

    Bolbasov, E N; Anissimov, Y G; Pustovoytov, A V; Khlusov, I A; Zaitsev, A A; Zaitsev, K V; Lapin, I N; Tverdokhlebov, S I

    2014-07-01

    A solution blow spinning technique is a method developed recently for making nonwoven webs of micro- and nanofibres. The principal advantage of this method compared to a more traditional electrospinning process is its significantly higher production rate. In this work, the solution blow spinning method was further developed to produce nonwoven polymeric scaffolds based on a copolymer of tetrafluoroethylene with vinylidene fluoride solution in acetone. A crucial feature of the proposed method is that high-voltage equipment is not required, which further improves the method's economics. Scanning electron microscopy analysis of the samples demonstrated that the surface morphology of the nonwoven materials is dependent on the polymer concentration in the spinning solution. It was concluded that an optimum morphology of the nonwoven scaffolds for medical applications is achieved by using a 5% solution of the copolymer. It was established that the scaffolds produced from the 5% solution have a fractal structure and anisotropic mechanical properties. X-ray diffraction, infrared spectroscopy, Raman spectroscopy and differential scanning calorimetry demonstrated that the fabricated nonwoven materials have crystal structures that exhibit ferroelectric properties. Gas chromatography has shown that the amount of acetone in the nonwoven material does not exceed the maximum allowable concentration of 0.5%. In vitro analysis, using the culture of motile cells, confirmed that the nonwoven material is non-toxic and does not alter the morpho-functional status of stem cells for short-term cultivation, and therefore can potentially be used in medical applications.

  14. Towards excimer-laser-based stereolithography: a rapid process to fabricate rigid biodegradable photopolymer scaffolds.

    PubMed

    Beke, S; Anjum, F; Tsushima, H; Ceseracciu, L; Chieregatti, E; Diaspro, A; Athanassiou, A; Brandi, F

    2012-11-01

    We demonstrate high-resolution photocross-linking of biodegradable poly(propylene fumarate) (PPF) and diethyl fumarate (DEF) using UV excimer laser photocuring at 308 nm. The curing depth can be tuned in a micrometre range by adjusting the total energy dose (total fluence). Young's moduli of the scaffolds are found to be a few gigapascal, high enough to support bone formation. The results presented here demonstrate that the proposed technique is an excellent tool for the fabrication of stiff and biocompatible structures on a micrometre scale with defined patterns of high resolution in all three spatial dimensions. Using UV laser photocuring at 308 nm will significantly improve the speed of rapid prototyping of biocompatible and biodegradable polymer scaffolds and enables its production in a few seconds, providing high lateral and horizontal resolution. This short timescale is indeed a tremendous asset that will enable a more efficient translation of technology to clinical applications. Preliminary cell tests proved that PPF : DEF scaffolds produced by excimer laser photocuring are biocompatible and, therefore, are promising candidates to be applied in tissue engineering and regenerative medicine.

  15. Synthesis and fabrication of a degradable poly(N-isopropyl acrylamide) scaffold for tissue engineering applications

    PubMed Central

    Galperin, Anna; Long, Thomas J.; Garty, Shai; Ratner, Buddy D.

    2013-01-01

    Biodegradable poly(N-isopropyl acrylamide) (poly-NIPAM) hydrogels with controlled molecular weight of the parent polymer and its degradation products were synthesized by atom transfer radical polymerization in the presence of a polycaprolactone-based di-chlorinated macroinitiator and polycaprolactone dimethacrylate. The phase transition temperature, swelling, hydrolytic degradability, and mechanical properties at 25 and 37°C were explored. A cytocompatibility study showed good NIH3T3 cell response over 5 days culture on the surface of the hydrogels, demonstrated by a consistent increase in cell proliferation detected by an Alamar Blue assay. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazo-lium bromide] results suggested that the hydrogels and their degradation products in the concentration range of 1–25 mg/ mL were not cytotoxic to NIH3T3 cells. A sphere-templating technique was utilized to fabricate biodegradable polyNIPAM scaffolds with monodisperse, pore size. Scaffolds with pore diameter of 48 ± 6 μm were loaded with A-10 smooth muscle cells and then warmed to 37°C entrapping cells in pores approximately 40 μm in diameter, a size we have found to be optimal for angiogenesis and biointegration. Due to their degradable nature, tunable molecular weight, highly interconnected morphology, thermally controlled monodisperse pore size, and temperature-induced volume expansion–contraction, the polyNIPAM-based scaffolds developed in this work will be valuable in tissue engineering. PMID:22961921

  16. A novel gellan-PVA nanofibrous scaffold for skin tissue regeneration: Fabrication and characterization.

    PubMed

    Vashisth, Priya; Nikhil, Kumar; Roy, Partha; Pruthi, Parul A; Singh, Rajesh P; Pruthi, Vikas

    2016-01-20

    In this investigation, we have introduced novel electrospun gellan based nanofibers as a hydrophilic scaffolding material for skin tissue regeneration. These nanofibers were fabricated using a blend mixture of gellan with polyvinyl alcohol (PVA). PVA reduced the repulsive force of resulting solution and lead to formation of uniform fibers with improved nanostructure. Field emission scanning electron microscopy (FESEM) confirmed the average diameter of nanofibers down to 50 nm. The infrared spectra (IR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis evaluated the crosslinking, thermal stability and highly crystalline nature of gellan-PVA nanofibers, respectively. Furthermore, the cell culture studies using human dermal fibroblast (3T3L1) cells established that these gellan based nanofibrous scaffold could induce improved cell adhesion and enhanced cell growth than conventionally proposed gellan based hydrogels and dry films. Importantly, the nanofibrous scaffold are biodegradable and could be potentially used as a temporary substrate/or biomedical graft to induce skin tissue regeneration. PMID:26572421

  17. Hydrothermal fabrication of porous hollow hydroxyapatite microspheres for a drug delivery system.

    PubMed

    Lai, Wen; Chen, Cen; Ren, Xiaoyuan; Lee, In-Seop; Jiang, Guohua; Kong, Xiangdong

    2016-05-01

    Porous hollow hydroxyapatite microspheres (PHHMs) are the promising biomaterials, owing to their excellent biocompatibility, biodegradability and bioactivity. PHHMs have been used as drug controlled carriers due to their advantages such as large drug loading capacity, nanochannels for drug loading and release and high specific surface area. In this study, PHHMs were prepared successfully in Na2HPO4 solution by an anion-exchange process using vaterite CaCO3 through a hydrothermal method. The previous vaterite CaCO3 was synthesized by a polymer-templated method in the poly(styrene sulfonic acid) sodium salt (PSS) aqueous solutions. The PHHMs have a size distribution from 0.8 to 2.0 μm, with an average pore size of about 24.3 nm. The wall of PHHMs is constructed with building units of hydroxyapatite nanofibers with an average length of 300 nm and an average width of 20 nm. The PHHMs displayed a high drug loading capacity and pH-responsive sustained-controlled drug release behavior when we used doxorubicin hydrochloride (DOX) as a loading drug. Moreover, the controlled drug release system showed a high ability to kill cancer cells and less damage to normal cells. These results indicated that PHHMs are promising for applications in various biomedical fields such as drug delivery system and oncotherapy.

  18. Hydrothermal fabrication of porous hollow hydroxyapatite microspheres for a drug delivery system.

    PubMed

    Lai, Wen; Chen, Cen; Ren, Xiaoyuan; Lee, In-Seop; Jiang, Guohua; Kong, Xiangdong

    2016-05-01

    Porous hollow hydroxyapatite microspheres (PHHMs) are the promising biomaterials, owing to their excellent biocompatibility, biodegradability and bioactivity. PHHMs have been used as drug controlled carriers due to their advantages such as large drug loading capacity, nanochannels for drug loading and release and high specific surface area. In this study, PHHMs were prepared successfully in Na2HPO4 solution by an anion-exchange process using vaterite CaCO3 through a hydrothermal method. The previous vaterite CaCO3 was synthesized by a polymer-templated method in the poly(styrene sulfonic acid) sodium salt (PSS) aqueous solutions. The PHHMs have a size distribution from 0.8 to 2.0 μm, with an average pore size of about 24.3 nm. The wall of PHHMs is constructed with building units of hydroxyapatite nanofibers with an average length of 300 nm and an average width of 20 nm. The PHHMs displayed a high drug loading capacity and pH-responsive sustained-controlled drug release behavior when we used doxorubicin hydrochloride (DOX) as a loading drug. Moreover, the controlled drug release system showed a high ability to kill cancer cells and less damage to normal cells. These results indicated that PHHMs are promising for applications in various biomedical fields such as drug delivery system and oncotherapy. PMID:26952411

  19. Micro-structured polymer scaffolds fabricated by direct laser writing for tissue engineering

    NASA Astrophysics Data System (ADS)

    Danilevicius, Paulius; Rekstyte, Sima; Balciunas, Evaldas; Kraniauskas, Antanas; Jarasiene, Rasa; Sirmenis, Raimondas; Baltriukiene, Daiva; Bukelskiene, Virginija; Gadonas, Roaldas; Malinauskas, Mangirdas

    2012-08-01

    This work presents the latest results on direct laser writing of polymeric materials for tissue engineering applications. A femtosecond Yb:KGW laser (300 fs, 200 kHz, 515 nm) was used as a light source for non-linear lithography. Fabrication was implemented in various photosensitive polymeric materials, such as: hybrid organic-inorganic sol-gel based on silicon-zirconium oxides, commercial ORMOCER class photoresins. These materials were structured via multi-photon polymerization technique with submicron resolution. Porous three-dimensional scaffolds for artificial tissue engineering were fabricated with constructed system and were up to several millimeters in overall size with 10 to 100 μm internal pores. Biocompatibility of the used materials was tested in primary rabbit muscle-derived stem cell culture in vitro and using laboratory rats in vivo. This interdisciplinary study suggests that proposed technique and materials are suitable for tissue engineering applications.

  20. Effects of fabrication on the mechanics, microstructure and micromechanical environment of small intestinal submucosa scaffolds for vascular tissue engineering.

    PubMed

    Sánchez-Palencia, Diana M; D'Amore, Antonio; González-Mancera, Andrés; Wagner, William R; Briceño, Juan C

    2014-08-22

    In small intestinal submucosa scaffolds for functional tissue engineering, the impact of scaffold fabrication parameters on success rate may be related to the mechanotransductory properties of the final microstructural organization of collagen fibers. We hypothesized that two fabrication parameters, 1) preservation (P) or removal (R) of a dense collagen layer present in SIS and 2) SIS in a final dehydrated (D) or hydrated (H) state, have an effect on scaffold void area, microstructural anisotropy (fiber alignment) and mechanical anisotropy (global mechanical compliance). We further integrated our experimental measurements in a constitutive model to explore final effects on the micromechanical environment inside the scaffold volume. Our results indicated that PH scaffolds might exhibit recurrent and large force fluctuations between layers (up to 195 pN), while fluctuations in RH scaffolds might be larger (up to 256 pN) but not as recurrent. In contrast, both PD and RD groups were estimated to produce scarcer and smaller fluctuations (not larger than 50 pN). We concluded that the hydration parameter strongly affects the micromechanics of SIS and that an adequate choice of fabrication parameters, assisted by the herein developed method, might leverage the use of SIS for functional tissue engineering applications, where forces at the cellular level are of concern in the guidance of new tissue formation.

  1. Transfer-Free Fabrication of Graphene Scaffolds on High-k Dielectrics from Metal-Organic Oligomers.

    PubMed

    Pang, Qingqing; Wang, Deyan; Wang, Xiuyan; Feng, Shaoguang; Clark, Michael B; Li, Qiaowei

    2016-09-28

    In situ fabrication of graphene scaffold-ZrO2 nanofilms is achieved by thermal annealing of Zr-based metal-organic oligomers on SiO2 substrates. The structural similarities of the aromatic moieties in the ligand (phenyl-, naphthyl-, anthryl-, and pyrenyl-) compared to graphene play a major role in the ordering of the graphene scaffolds obtained. The depth profiling analysis reveals ultrathin carbon-pure or carbon-rich surfaces of the graphene scaffold-ZrO2 nanofilms. The graphene scaffolds with ∼96.0% transmittance in the visible region and 4.8 nm in thickness can be grown with this non-chemical vapor deposition method. Furthermore, the heterogeneous graphene scaffold-ZrO2 nanofilms show a low sheet resistance of 17.0 kΩ per square, corresponding to electrical conductivity of 3197 S m(-1). The strategy provides a facile method to fabricate graphene scaffolds directly on high-k dielectrics without transferring process, paving the way for its application in fabricating electronic devices. PMID:27580799

  2. Fabrication and characterization of Mg/P(LLA-CL)-blended nanofiber scaffold.

    PubMed

    Li, Heyu; Wu, Tong; Zheng, Yufeng; El-Hamshary, Hany; Al-Deyab, Salem S; Mo, Xiumei

    2014-07-01

    Poly(l-lactic acid-co-ε-caprolactone) (P(LLA-CL)) is a kind of copolymer polymerized from lactic acid and ε-caprolactone. Electrospun P(LLA-CL) nanofibers have good biocompatibility, biodegradability, and mechanical property. However, this type of nanofibers will produce acid groups during the degradation, so that, the pH value of the environment will decrease and result in tissue inflammation. On the other hand, Magnesium (Mg) alloy tissue engineering scaffolds will show alkaline during the degradation because of the electrochemical corrosion. Based on the principle of acid-based neutralization, combination of these two kinds of materials through electrospinning could keep the pH of the degradation environment neutral. In this paper, fabrication and characterization of Mg/P(LLA-CL)-blended nanofiber scaffolds with different ratios will be studied by scanning electron microscopy and universal materials testing machines to observe the morphology and mechanical properties of nanofibers, respectively. Furthermore, PIECs were cultured and seeded on the scaffolds for different time to evaluate the proliferation behavior on the scaffolds by MTT assay. The degradation tests of the samples lasted for three months in phosphate-buffered saline to evaluate the pH values of degradation solutions and the weight loss of nanofibers during degradation. The results showed that the mechanical property and biocompatibility of Mg/P(LLA-CL)-blended nanofibers were worse than that of pure P(LLA-CL). Moreover, the addition of Mg in the nanofibers accelerated the weight loss of the Mg/P(LLA-CL) blending fibers and increased the pH values of the environment during degradation of Mg/P(LLA-CL)-blended nanofibers.

  3. Gelatin-GAG electrospun nanofibrous scaffold for skin tissue engineering: fabrication and modeling of process parameters.

    PubMed

    Pezeshki-Modaress, Mohamad; Mirzadeh, Hamid; Zandi, Mojgan

    2015-03-01

    Electrospinning is a very useful technique for producing polymeric nanofibers by applying electrostatic forces. In this study, fabrication of novel gelatin/GAG nanofibrous mats and also the optimization of electrospinning process using response surface methodology were reported. At optimization section, gelatin/GAG blend ratio, applied voltage and feeding rate, their individual and interaction effects on the mean fiber diameter (MFD) and standard deviation of fiber diameter (SDF) were investigated. The obtained model for MFD has a quadratic relationship with gelatin/GAG blend ratio, applied voltage and feeding rate. The interactions of blend ratio and applied voltage and also applied voltage and flow rate were found significant but the interactions of blend ratio and flow rate were ignored. The optimum condition for gelatin/GAG electrospinning was also introduced using the model obtained in this study. The potential use of optimized electrospun mat in skin tissue engineering was evaluated using culturing of human dermal fibroblast cells (HDF). The SEM micrographs of HDF cells on the nanofibrous structure show that fibroblast cells can highly attach, grow and populate on the fabricated scaffold surface. The electrospun gelatin/GAG nanofibrous mats have a potential for using as scaffold for skin, cartilage and cornea tissue engineering.

  4. Cauda equina-derived extracellular matrix for fabrication of nanostructured hybrid scaffolds applied to neural tissue engineering.

    PubMed

    Wen, Xiaoxiao; Wang, Yu; Guo, Zhiyuan; Meng, Haoye; Huang, Jingxiang; Zhang, Li; Zhao, Bin; Zhao, Qing; Zheng, Yudong; Peng, Jiang

    2015-03-01

    Extracellular matrix (ECM) components have become important candidate materials for use as neural scaffolds for neural tissue engineering. In the current study, we prepared cauda equina-derived ECM materials for the production of scaffolds. Natural porcine cauda equina was decellularized using Triton X-100 and sodium deoxycholate, shattered physically, and made into a suspension by differential centrifugation. The decellularization procedure resulted in the removal of >94% of the nuclear material and preserved the extracellular collagen and sulfated glycosaminoglycan. Immunofluorescent staining confirmed the presence of collagen type I, laminin, and fibronectin in the ECM. The cauda equine-derived ECM was blended with poly(l-lactide-co-glycolide) (PLGA) to fabricate nanostructured scaffolds using electrospinning. The incorporation of the ECM increased the hydrophilicity of the scaffolds. Fourier transform infrared spectroscopy and multiphoton-induced autofluorescence images showed the presence of the ECM in the scaffolds. ECM/PLGA scaffolds were beneficial for the survival of Schwann cells compared with scaffolds consisting of PLGA alone, and the aligned fibers could regulate cell morphologic features by modulating cellular orientation. Axons in the dorsal root ganglia explants extended to a greater extent along ECM/PLGA compared with PLGA-alone fibers. The cauda equina ECM might be a promising material for forming scaffolds for use in neural tissue engineering. PMID:25366704

  5. Cauda Equina-Derived Extracellular Matrix for Fabrication of Nanostructured Hybrid Scaffolds Applied to Neural Tissue Engineering

    PubMed Central

    Wen, Xiaoxiao; Wang, Yu; Guo, Zhiyuan; Meng, Haoye; Huang, Jingxiang; Zhang, Li; Zhao, Bin; Zhao, Qing

    2015-01-01

    Extracellular matrix (ECM) components have become important candidate materials for use as neural scaffolds for neural tissue engineering. In the current study, we prepared cauda equina-derived ECM materials for the production of scaffolds. Natural porcine cauda equina was decellularized using Triton X-100 and sodium deoxycholate, shattered physically, and made into a suspension by differential centrifugation. The decellularization procedure resulted in the removal of >94% of the nuclear material and preserved the extracellular collagen and sulfated glycosaminoglycan. Immunofluorescent staining confirmed the presence of collagen type I, laminin, and fibronectin in the ECM. The cauda equine-derived ECM was blended with poly(l-lactide-co-glycolide) (PLGA) to fabricate nanostructured scaffolds using electrospinning. The incorporation of the ECM increased the hydrophilicity of the scaffolds. Fourier transform infrared spectroscopy and multiphoton-induced autofluorescence images showed the presence of the ECM in the scaffolds. ECM/PLGA scaffolds were beneficial for the survival of Schwann cells compared with scaffolds consisting of PLGA alone, and the aligned fibers could regulate cell morphologic features by modulating cellular orientation. Axons in the dorsal root ganglia explants extended to a greater extent along ECM/PLGA compared with PLGA-alone fibers. The cauda equina ECM might be a promising material for forming scaffolds for use in neural tissue engineering. PMID:25366704

  6. Laser microfabrication of hydroxyapatite-osteoblast-like cell composites.

    PubMed

    Doraiswamy, A; Narayan, R J; Harris, M L; Qadri, S B; Modi, R; Chrisey, D B

    2007-03-01

    We have developed a novel approach for layer-by-layer growth of tissue-engineered materials using a direct writing process known as matrix assisted pulsed laser evaporation direct write (MAPLE DW). Unlike conventional cell-seeding methods, this technique provides the possibility for cell-material integration prior to artificial tissue fabrication. This process also provides greater flexibility in selection and processing of scaffold materials. In addition, MAPLE DW offers rapid computer-controlled deposition of mesoscopic voxels at high spatial resolutions. We have examined MAPLE DW processing of zirconia and hydroxyapatite scaffold materials that can provide a medical device with nearly inert and bioactive implant-tissue interfaces, respectively. We have also demonstrated codeposition of hydroxyapatite, MG 63 osteoblast-like cells, and extracellular matrix using MAPLE DW. We have shown that osteoblast-like cells remain viable and retain the capacity for proliferation when codeposited with bioceramic scaffold materials. Our results on MG 63-hydroxyapatite composites can be extended to develop other integrated cell-scaffold structures for medical and dental applications.

  7. A Facile and Effective Approach to Fabricate Chitosan/Hydroxyapatite Nanocomposite Coating on the Surface of Wood from Chinese Glossy Privet.

    PubMed

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

    2016-06-01

    A chitosan/hydroxyapatite nanocomposite coating was fabricated on the surface of wood from Chinese Glossy Privet (CGP) and could adhere compactly to the wood surface. Fourier transform infrared spectra analysis indicated that the interaction between chitosan and hydroxyapatite might exist. In addition, sodium bicarbonate was added into the nanocomposite during the preparation process making the boating porous in acidic surrounding through effervescence effect. Field emission scanning electron microscope characterizations showed the nanocomposite (M(CS):M(HA) = 1:1, with 30% NaHCO3) was optimal and such composite was stable, which was verified by thermal analysis and in vitro degradation study. This work could provide a facile and effective fabricating approach of biocompatible material which may have some potential applications as bone-repairing material. PMID:27427648

  8. Fabrication and characterisation of biomimetic, electrospun gelatin fibre scaffolds for tunica media-equivalent, tissue engineered vascular grafts.

    PubMed

    Elsayed, Y; Lekakou, C; Labeed, F; Tomlins, P

    2016-04-01

    It is increasingly recognised that biomimetic, natural polymers mimicking the extracellular matrix (ECM) have low thrombogenicity and functional motifs that regulate cell-matrix interactions, with these factors being critical for tissue engineered vascular grafts especially grafts of small diameter. Gelatin constitutes a low cost substitute of soluble collagen but gelatin scaffolds so far have shown generally low strength and suture retention strength. In this study, we have devised the fabrication of novel, electrospun, multilayer, gelatin fibre scaffolds, with controlled fibre layer orientation, and optimised gelatin crosslinking to achieve not only compliance equivalent to that of coronary artery but also for the first time strength of the wet tubular acellular scaffold (swollen with absorbed water) same as that of the tunica media of coronary artery in both circumferential and axial directions. Most importantly, for the first time for natural scaffolds and in particular gelatin, high suture retention strength was achieved in the range of 1.8-1.94 N for wet acellular scaffolds, same or better than that for fresh saphenous vein. The study presents the investigations to relate the electrospinning process parameters to the microstructural parameters of the scaffold, which are further related to the mechanical performance data of wet, crosslinked, electrospun scaffolds in both circumferential and axial tubular directions. The scaffolds exhibited excellent performance in human smooth muscle cell (SMC) proliferation, with SMCs seeded on the top surface adhering, elongating and aligning along the local fibres, migrating through the scaffold thickness and populating a transverse distance of 186 μm and 240 μm 9 days post-seeding for scaffolds of initial dry porosity of 74 and 83%, respectively. PMID:26838874

  9. Three-dimensional extracellular matrix scaffolds by microfluidic fabrication for long-term spontaneously contracted cardiomyocyte culture.

    PubMed

    Mei, Jeng-Chun; Wu, Aden Yuan Kun; Wu, Po-Chen; Cheng, Nai-Chen; Tsai, Wei-Bor; Yu, Jiashing

    2014-11-01

    To repair damaged cardiac tissue, the important principle of in vitro cell culture is to mimic the in vivo cell growth environment. Thus, micro-sized cells are more suitably cultured in three-dimensional (3D) than in two-dimensional (2D) microenvironments (ex: culture dish). With the matching dimensions of works produced by microfluidic technology, chemical engineering and biochemistry applications have used this technology extensively in cellular works. The 3D scaffolds produced in our investigation has essential properties, such has high mass transfer efficiency, and variable pore sizes, to adapt to various needs of different cell types. In addition to the malleability of these innovative scaffolds, fabrication procedure was effortless and fast. Primary neonatal mice cardiomyocytes were successfully harvested and cultured in 3D scaffolds made of gelatin and collagen. Gelatin and gelatin-collagen scaffold were produced by the formation of microbubbles through a microfluidic device, and the mechanical properties of gelatin scaffold and gelatin-collagen scaffold were measured. Cellular properties in the microbubbles were also monitored. Fluorescence staining results assured that cardiomyocytes could maintain in vivo morphology in 3D gelatin scaffold. In addition, it was found that 3D scaffold could prolong the contraction behavior of cardiomyocytes compared with a conventional 2D culture dish. Spontaneously contracted behavior was maintained for the longest (about 1 month) in the 3D gelatin scaffold, about 19 days in the 3D gelatin-collagen scaffold. To sum up, this 3D platform for cell culture has promising potential for myocardial tissue engineering. PMID:24851797

  10. Projection Stereolithographic Fabrication of Human Adipose Stem Cell-Incorporated Biodegradable Scaffolds for Cartilage Tissue Engineering

    PubMed Central

    Sun, Aaron X.; Lin, Hang; Beck, Angela M.; Kilroy, Evan J.; Tuan, Rocky S.

    2015-01-01

    The poor self-healing ability of cartilage necessitates the development of methods for cartilage regeneration. Scaffold construction with live stem cell incorporation and subsequent differentiation presents a promising route. Projection stereolithography (PSL) offers high resolution and processing speed as well as the ability to fabricate scaffolds that precisely fit the anatomy of cartilage defects using medical imaging as the design template. We report here the use of a visible-light-based PSL (VL-PSL) system to encapsulate human adipose-derived stem cells (hASCs) into a biodegradable polymer [poly-d,l-lactic acid/polyethylene glycol/poly-d,l-lactic acid (PDLLA-PEG)]/hyaluronic acid (HA) matrix to produce live cell constructs with customized architectures. After fabrication, hASCs showed high viability (84%) and were uniformly distributed throughout the constructs, which possessed high mechanical properties with a compressive modulus of 780 kPa. The hASC-seeded constructs were then cultured in control or TGF-β3-containing chondrogenic medium for up to 28 days. In chondrogenic medium-treated group (TGF-β3 group), hASCs maintained 77% viability and expressed chondrogenic genes Sox9, collagen type II, and aggrecan at 11, 232, and 2.29 × 105 fold increases, respectively compared to levels at day 0 in non-chondrogenic medium. The TGF-β3 group also produced a collagen type II and glycosaminoglycan-rich extracellular matrix, detected by immunohistochemistry, Alcian blue staining, and Safranin O staining suggesting robust chondrogenesis within the scaffold. Without chondroinductive addition (Control group), cell viability decreased with time (65% at 28 days) and showed poor cartilage matrix deposition. After 28 days, mechanical strength of the TGF-β3 group remained high at 240 kPa. Thus, the PSL and PDLLA-PEG/HA-based fabrication method using adult stem cells is a promising approach in producing mechanically competent engineered cartilage for joint

  11. Fabrication of collagen scaffolds impregnated with sago starch capped silver nanoparticles suitable for biomedical applications and their physicochemical studies.

    PubMed

    Mandal, Abhishek; Sekar, Santhanam; Seeni Meera, Kamal Mohamed; Mukherjee, Amitava; Sastry, Thotapalli P; Mandal, Asit Baran

    2014-10-01

    The present investigation attempts at fabricating collagen-based scaffolds impregnated with sago starch capped silver nanoparticles (AgNPs), useful for biomedical applications, and aims at studying their physicochemical aspects. AgNPs synthesized through a chemical reduction method, capped using different concentrations of sago starch, are incorporated into collagen derived from fish scales, and lyophilized to form scaffolds. FT-IR spectra confirm and validate the interaction of sago starch capped AgNPs with collagen in the scaffolds. TGA and DSC results indicate enhanced thermal stability of collagen scaffolds impregnated with sago capped AgNPs compared to collagen alone. All the collagen scaffolds containing sago starch capped AgNPs show high tensile strength values for their use as wound dressing materials. Moreover, lower minimum inhibitory concentration values are obtained for the above capped AgNP collagen scaffolds, which indicate higher antibacterial activities compared to uncapped AgNPs tested against both gram positive and negative bacterial strains. The novelty is that the developed scaffolds are biodegradable and in vitro studies reveal them as biocompatible and suitable for tissue regeneration applications. PMID:25138771

  12. Design and Fabrication of a Biodegradable, Covalently Crosslinked Shape-Memory Alginate Scaffold for Cell and Growth Factor Delivery

    PubMed Central

    Wang, Lin; Shansky, Janet; Borselli, Cristina; Mooney, David

    2012-01-01

    The successful use of transplanted cells and/or growth factors for tissue repair is limited by a significant cell loss and/or rapid growth factor diffusion soon after implantation. Highly porous alginate scaffolds formed with covalent crosslinking have been used to improve cell survival and growth factor release kinetics, but require open-wound surgical procedures for insertion and have not previously been designed to readily degrade in vivo. In this study, a biodegradable, partially crosslinked alginate scaffold with shape-memory properties was fabricated for minimally invasive surgical applications. A mixture of high and low molecular weight partially oxidized alginate modified with RGD peptides was covalently crosslinked using carbodiimide chemistry. The scaffold was compressible 11-fold and returned to its original shape when rehydrated. Scaffold degradation properties in vitro indicated ∼85% mass loss by 28 days. The greater than 90% porous scaffolds released the recombinant growth factor insulin-like growth factor-1 over several days in vitro and allowed skeletal muscle cell survival, proliferation, and migration from the scaffold over a 28-day period. The compressible scaffold thus has the potential to be delivered by a minimally invasive technique, and when rehydrated in vivo with cells and/or growth factors, could serve as a temporary delivery vehicle for tissue repair. PMID:22646518

  13. Bioceramic coating of hydroxyapatite fabricated on Ti-6Al-4V with Nd-YAG laser

    NASA Astrophysics Data System (ADS)

    Tlotleng, Monnamme; Akinlabi, Esther T.; Shukla, Mukul; Pityana, Sisa

    2015-03-01

    This paper presents on the direct laser melted hydroxyapatite coatings achieved by melting the pre-placed powder beds using Nd-YAG laser. The process development and optimized parameters are reported. The results show that by changing the laser power and the beam inclined plane it is possible that a desirable coating of HAP that is rich on the surface can be produced. The microstructures of the coatings showed balling and cracking at beam angles between 0-15° and at 27° a successful coating was achieved with laser power and scanning speed of 750W and 5mm/s respectively. The said coating was pore and crack free while it retained non-decomposed HAP crystallites on the surface (mixed). The microstructure of the transition layer concluded a moderate temperature process since the formed dendrites did not develop or form secondary arms. The Ca/P conducted on the coating using EDS concluded Ca/P ratio of 8.04 and the absence of titanium phosphates phase (TiP2). TiP2 is typically associated with the decomposition of HAP and indicate the presence of high processing temperatures. Even so, the current results indicated that the investigated process was successful in depositing HAP coating with desirable microstructures even though its bio-corrosion properties still need to be ascertained before it could be qualified as suitable for biomedical applications.

  14. Structure-property relationships of iron-hydroxyapatite ceramic matrix nanocomposite fabricated using mechanosynthesis method.

    PubMed

    Nordin, Jamillah Amer; Prajitno, Djoko Hadi; Saidin, Syafiqah; Nur, Hadi; Hermawan, Hendra

    2015-06-01

    Hydroxyapatite (HAp) is an attractive bioceramics due to its similar composition to bone mineral and its ability to promote bone-implant interaction. However, its low strength has limited its application as load bearing implants. This paper presented a work focusing on the improvement of HAp mechanical property by synthesizing iron (Fe)-reinforced bovine HAp nanocomposite powders via mechanosynthesis method. The synthesis process was performed using high energy milling at varied milling time (3, 6, 9, and 12h). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Its mechanical properties were investigated by micro-Vicker's hardness and compression tests. Results showed that milling time directly influenced the characteristics of the nanocomposite powders. Amorphous BHAp was formed after 9 and 12h milling in the presence of HPO4(2-) ions. Continuous milling has improved the crystallinity of Fe without changing the HAp lattice structure. The nanocomposite powders were found in spherical shape, agglomerated and dense after longer milling time. The hardness and Young's modulus of the nanocomposites were also increased at 69% and 66%, respectively, as the milling time was prolonged from 3 to 12h. Therefore, the improvement of the mechanical properties of nanocomposite was attributed to high Fe crystallinity and homogenous, dense structure produced by mechanosynthesis. PMID:25842138

  15. Structure-property relationships of iron-hydroxyapatite ceramic matrix nanocomposite fabricated using mechanosynthesis method.

    PubMed

    Nordin, Jamillah Amer; Prajitno, Djoko Hadi; Saidin, Syafiqah; Nur, Hadi; Hermawan, Hendra

    2015-06-01

    Hydroxyapatite (HAp) is an attractive bioceramics due to its similar composition to bone mineral and its ability to promote bone-implant interaction. However, its low strength has limited its application as load bearing implants. This paper presented a work focusing on the improvement of HAp mechanical property by synthesizing iron (Fe)-reinforced bovine HAp nanocomposite powders via mechanosynthesis method. The synthesis process was performed using high energy milling at varied milling time (3, 6, 9, and 12h). The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Its mechanical properties were investigated by micro-Vicker's hardness and compression tests. Results showed that milling time directly influenced the characteristics of the nanocomposite powders. Amorphous BHAp was formed after 9 and 12h milling in the presence of HPO4(2-) ions. Continuous milling has improved the crystallinity of Fe without changing the HAp lattice structure. The nanocomposite powders were found in spherical shape, agglomerated and dense after longer milling time. The hardness and Young's modulus of the nanocomposites were also increased at 69% and 66%, respectively, as the milling time was prolonged from 3 to 12h. Therefore, the improvement of the mechanical properties of nanocomposite was attributed to high Fe crystallinity and homogenous, dense structure produced by mechanosynthesis.

  16. Evaluation of thermal stress in hydroxyapatite film fabricated by powder jet deposition.

    PubMed

    Akatsuka, Ryo; Matsumura, Ken; Noji, Miyoko; Kuriyagawa, Tsunemoto; Sasaki, Keiichi

    2013-10-01

    This study aimed to create a thick hydroxyapatite (HA) film on the surface of a human tooth via a powder jet deposition (PJD) device for dental handpieces, and to examine the microstructural and mechanical properties of the HA film. In particular, the effects of thermal stress on this film were evaluated. The HA film was created by blasting 3.18-μm HA particles, calcinated at 1,200°C, onto the enamel substrate at room temperature and atmospheric pressure. An HA film with an area of 3 mm × 3 mm was prepared and polished. The following HA film parameters were evaluated from the three-dimensional surface profile: surface roughness, Vickers hardness, and bonding strength before and after artificial aging induced by 500 cycles of thermal cycling (5-55°C). The HA particles in the deposited film were densely packed, and the surface of the HA film was unchanged after thermal cycling. There were also no significant differences in the hardness and the bonding strength of the HA film before and after thermal cycling. The HA film created in this study demonstrated excellent microstructural and mechanical properties, even after the application of thermal stress.

  17. Fabrication of DNA/Hydroxyapatite nanocomposites by simulated body fluid for gene delivery

    SciTech Connect

    Takeshita, Takayuki; Okamoto, Masami

    2015-05-22

    The hydroxyapatite (HA) formation on the surface of DNA molecules in simulated body fluid (SBF) was examined. The osteoconductivity is estimated using SBF having ion concentrations approximately equal to those of human blood plasma. After immersion for 4 weeks in SBF at 36.5 °C, the HA crystallites possessing 1-14 micrometer in diameter grew on the surface of DNA molecules. The leaf flake-like and spherical shapes morphologies were observed through scanning electron microscopy analysis. Original peaks of both of DNA and HA were characterized by fourier transform infrared spectroscopy. The Ca/P ratio (1.1-1.5) in HA was estimated by energy dispersive X-ray analysis. After biomineralization, the calculated weight ratio of DNA/HA was 18/82 by thermogravimetry/differential thermal analysis. The molecular orbital computer simulation has been used to probe the interaction of DNA with two charge-balancing ions, CaOH{sup +} and CaH{sub 2}PO{sub 4}{sup +}. The adsorption enthalpy of the two ions on DNA having negative value was the evidence for the interface in mineralization of HA in SBF.

  18. Fabrication and physico-mechanical properties of thin magnetron sputter deposited silver-containing hydroxyapatite films

    NASA Astrophysics Data System (ADS)

    Ivanova, A. A.; Surmeneva, M. A.; Tyurin, A. I.; Pirozhkova, T. S.; Shuvarin, I. A.; Prymak, O.; Epple, M.; Chaikina, M. V.; Surmenev, R. A.

    2016-01-01

    As a measure of the prevention of implant associated infections, a number of strategies have been recently applied. Silver-containing materials possessing antibacterial activity as expected might have wide applications in orthopedics and dentistry. The present work focuses on the physico-chemical characterization of silver-containing hydroxyapatite (Ag-HA) coating obtained by radio frequency (RF) magnetron sputtering. Mechanochemically synthesized Ag-HA powder (Ca10-xAgx(PO4)6(OH)2-x, x = 1.5) was used as a precursor for sputtering target preparation. Morphology, composition, crystallinity, physico-mechanical features (Young's modulus and nanohardness) of the deposited Ag-HA coatings were investigated. The sputtering of the nanostructured multicomponent target at the applied process conditions allowed to deposit crystalline Ag-HA coating which was confirmed by XRD and FTIR data. The SEM results revealed the formation of the coating with the grain morphology and columnar cross-section structure. The EDX analysis confirmed that Ag-HA coating contained Ca, P, O and Ag with the Ca/P ratio of 1.6 ± 0.1. The evolution of the mechanical properties allowed to conclude that addition of silver to HA film caused increase of the coating nanohardness and elastic modulus compared with those of pure HA thin films deposited under the same deposition conditions.

  19. Hydroxyapatite coatings with oriented nanoplate and nanorod arrays: Fabrication, morphology, cytocompatibility and osteogenic differentiation.

    PubMed

    Chen, Wei; Tian, Bo; Lei, Yong; Ke, Qin-Fei; Zhu, Zhen-An; Guo, Ya-Ping

    2016-10-01

    Hydroxyapatite (HA) crystals exhibit rod-like shape with c-axis orientation and plate-like shape with a(b)-axis orientation in vertebrate bones and tooth enamel surfaces, respectively. Herein, we report the synthesis of HA coatings with the oriented nanorod arrays (RHACs) and HA coatings with oriented nanoplate arrays (PHACs) by using bioglass coatings as sacrificial templates. After soaking in simulated body fluid (SBF) at 120°C, the bioglass coatings are hydrothermally converted into the HA coatings via a dissolution-precipitation reaction. If the Ca/P ratios in SBF are 2.50 and 1.25, the HA crystals on the coatings are oriented nanorod arrays and oriented nanoplate arrays, respectively. Moreover, the bioglass coatings are treated with SBF at 37°C, plate-like HA coatings with a low crystallinity (SHACs) are prepared. As compared with the Ti6Al4V and SHACs, the human bone marrow stromal cells (hBMSCs) on the RHACs and PHACs have better cell adhesion, spreading, proliferation and osteogenic differentiation because of their moderately hydrophilic surfaces and similar chemical composition, morphology and crystal orientation to human hard tissues. Notably, the morphologies of HA crystals have no obvious effects on cytocompatibility and osteogenic differentiation. Hence, the HA coatings with oriented nanoplate arrays or oriented nanorod arrays have a great potential for orthopedic applications. PMID:27287136

  20. Fabrication and mechanical characterization of 3D electrospun scaffolds for tissue engineering.

    PubMed

    Wright, L D; Young, R T; Andric, T; Freeman, J W

    2010-10-01

    Electrospinning is a polymer processing technique that produces fibrous structures comparable to the extracellular matrix of many tissues. Electrospinning, however, has been severely limited in its tissue engineering capabilities because this technique has produced few three-dimensional structures. Sintering of electrospun materials provides a method to fabricate unique architectures and allow much larger structures to be made. Electrospun mats were sintered into strips and cylinders, and their tensile and compressive mechanical properties were measured. In addition, electrospun materials with salt pores (salt embedded within the material and then leached out) were fabricated to improve porosity of the electrospun materials for tissue engineering scaffolds. Sintered electrospun poly(D,L-lactide) and poly(L-lactide) (PDLA/PLLA) materials have higher tensile mechanical properties (modulus: 72.3 MPa, yield: 960 kPa) compared to unsintered PLLA (modulus: 40.36 MPa, yield: 675.5 kPa). Electrospun PDLA/PLLA cylinders with and without salt-leached pores had compressive moduli of 6.69 and 26.86 MPa, respectively, and compressive yields of 1.36 and 0.56 MPa, respectively. Sintering of electrospun materials is a novel technique that improves electrospinning application in tissue engineering by increasing the size and types of electrospun structures that can be fabricated.

  1. Characterization of fabricated three dimensional scaffolds of bioceramic-polymer composite via microstereolithography technique

    NASA Astrophysics Data System (ADS)

    Talib, Marina; Covington, James A.; Bolarinwa, Aminat

    2014-02-01

    Microstereolithography is a method used for rapid prototyping of polymeric and ceramic components. This technique converts a computer-aided design (CAD) to a three dimensional (3D) model, and enables layer per layer fabrication curing a liquid resin with UV-light or laser source. The aim of this project was to formulate photocurable polymer reinforced with synthesized calcium pyrophosphate (CPP), and to fabricate a 3D scaffolds with optimum mechanical properties for specific tissue engineering applications. The photocurable ceramic suspension was prepared with acrylate polyester, multifunctional acrylate monomer with the addition of 50-70wt% of CPP, photoinitiators and photoinhibitors. The 3D structure of disc (5 mm height × 4 mm diameter) was successfully fabricated using Envisiontec Perfactory3® . They were then sintered at high temperature for polymer removal, to obtain a ceramic of the desired porosity. The density increased to more than 35% and the dimensional shrinkage after sintering were 33%. The discs were then subjected compressive measurement, biodegradation and bioactivity test. Morphology and CPP content of the sintered polymer was investigated with SEM and XRD, respectively. The addition of CPP coupled with high temperature sintering, had a significant effect on the compressive strength exhibited by the bioceramic. The values are in the range of cancellous bone (2-4 MPa). In biodegradation and bioactivity test, the synthesized CPP induced the formation of apatite layer and its nucleation onto the composite surface.

  2. Applying Electrospun Gelatin/Poly(lactic acid-co-glycolic acid) Bilayered Nanofibers to Fabrication of Meniscal Tissue Engineering Scaffold.

    PubMed

    Li, Peng; Zhang, Weiguo; Yu, Hongquan; Zheng, Lianjie; Yang, Liang; Liu, Gang; Sheng, Chenchen; Gui, Haoran; Ni, Shuo; Li, Pengsheng; Shi, Feng

    2016-05-01

    The menisci are fibrocartilaginous tissues composed primarily of an interlacing network of collagen fibers with nanoscale diameter. Electrospinning is a suitable process of producing nanoscale fibers that mimic collagen fibers. In this study, a bilayered scaffold (group B), which consists of a gelatin nanofiber mesh and a PLGA nanofiber mesh, has been fabricated through an electrospinning method. At the same time, we electrospun pure PLGA fibrous mesh (group A) and gelatin/PLGA composite fibrous mesh (group C) as control groups. In order to compare all scaffold morphologies, the scaffolds were imaged by SEM and some parameters were measured and analyzed as following: Diameters of fibrils are from the smallest of less than average 0.14 μm for group C to the biggest of nearly average 0.38 μm for group B. The scaffolds pore diameters are from average 4.9 μm for group A to average 11.2 μm for group B. Porosity rates show that the group B has the highest porosity rate at about 91%. The scaffolds' properties were compared and analyzed, including hydrophilicity property (water contact angle) and mechanical properties (tensile strength). The results of water contact angle showed the group B is the most hydrophil among the groups. The results of tensile strength showed the tensile strength of group C is the weakest among the groups. All the results showed significant differences between the groups. Finally, in vitro, the meniscal cells derived from New Zealand white rabbits menisci were seeded in the scaffolds. We observed the cells proliferation behavior in the scaffolds. All above demonstrates that a bi-layered gelatin/PLGA scaffold reveals not only concurrent effects of mechanics and cytocompatibility in a fibrous context, but also a promising scaffold for future meniscal repair strategies. PMID:27483813

  3. Fabrication of nano-porous hydroxyapatite modified electrode and its application for determination of p-chlorophenol.

    PubMed

    Chu, Lin; Zhang, Xiaoli

    2012-01-01

    Nano-porous hydroxyapatite (HAp) modified electrode was fabricated by simply electrodepositing HAp onto the glassy carbon electrode (GCE) from the electrolytes solution containing Ca(NO3)2 4H2O and NH4H2PO4, the resulting electrode (nano-HAp/GCE) was characterized with scanning electron microscopy (SEM). The electrochemical behavior of p-chlorophenol (p-CP) at nano-HAp/GCE was studied by cyclic voltammetry. The electrode displayed selective and enhanced electroanalytical response towards p-CP, obviously because p-CP is accumulated at the electrode. For the greater sensitivity, a semi-derivative technique was adopted to obtain the current signal. The results indicated that the nano-HAp/GCE exhibits substantial enhancement in electrochemical sensitivity for p-CP due to its large surface area and particular adsorbability. After accumulation of 4 min for p-CP on nano-HAp/GCE, the peak height was linearly related to the concentration of p-CP in the range of 1.0 x 10(-8) to 1.0 x 10(-7) mol L(-1). The detection limit was 4.0 x 10(-9) mol L-(1) at 3sigma level. Based on this, the modified electrode was successfully applied in water samples with low cost and high sensitivity.

  4. Fabrication of hydroxyapatite and TiO 2 nanorods on microarc-oxidized titanium surface using hydrothermal treatment

    NASA Astrophysics Data System (ADS)

    Song, Ho-Jun; Kim, Ji-Woo; Kook, Min-Suk; Moon, Won-Jin; Park, Yeong-Joon

    2010-09-01

    AC-type microarc oxidation (MAO) and hydrothermal treatment techniques were used to enhance the bioactivity of commercially pure titanium (CP-Ti). The porous TiO 2 layer fabricated by the MAO treatment had a dominant anatase structure and contained Ca and P ions. The MAO-treated specimens were treated hydrothermally to form HAp crystallites on the titanium oxide layer in an alkaline aqueous solution (OH-solution) or phosphorous-containing alkaline solution (POH-solution). A small number of micro-sized hydroxyapatite (HAp) crystallites and a thin layer composed of nano-sized HAps were formed on the Ti-MAO-OH group treated hydrothermally in an OH-solution, whereas a large number of micro-sized HAp crystallites and dense anatase TiO 2 nanorods were formed on the Ti-MAO-POH group treated hydrothermally in a POH-solution. The layer of bone-like apatite that formed on the surface of the POH-treated sample after soaking in a modified simulated body fluid was thicker than that on the OH-treated samples.

  5. Combination of thermal extrusion printing and ultrafast laser fabrication for the manufacturing of 3D composite scaffolds

    NASA Astrophysics Data System (ADS)

    Balčiūnas, Evaldas; Lukoševičius, Laurynas; Mackevičiūtė, Dovilė; Rekštytė, Sima; Rutkūnas, Vygandas; Paipulas, Domas; Stankevičiūtė, Karolina; Baltriukienė, Daiva; Bukelskienė, Virginija; Piskarskas, Algis P.; Malinauskas, Mangirdas

    2014-03-01

    We present a novel approach to manufacturing 3D microstructured composite scaffolds for tissue engineering applications. A thermal extrusion 3D printer - a simple, low-cost tabletop device enabling rapid materialization of CAD models in plastics - was used to produce cm-scale microporous scaffolds out of polylactic acid (PLA). The fabricated objects were subsequently immersed in a photosensitive monomer solution and direct laser writing technique (DLW) was used to refine its inner structure by fabricating a fine mesh inside the previously produced scaffold. In addition, a composite material structure out of four different materials fabricated via DLW is presented. This technique, empowered by ultrafast lasers allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. A composite scaffold made of distinct materials and periodicities is acquired after the development process used to wash out non-linked monomers. Another way to modify the 3D printed PLA surfaces was also demonstrated - ablation with femtosecond laser beam. Structure geometry on macro- to micro- scales could be finely tuned by combining these fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. To our best knowledge, this is the first experimental demonstration showing the creation of composite 3D scaffolds using convenient 3D printing combined with DLW. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro-featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of tissue engineering, as well as in microelectromechanical systems, microfluidics, microoptics and others.

  6. Fabrication of poly (ϵ-caprolactone) microfiber scaffolds with varying topography and mechanical properties for stem cell-based tissue engineering applications.

    PubMed

    Ko, Junghyuk; Mohtaram, Nima Khadem; Ahmed, Farid; Montgomery, Amy; Carlson, Michael; Lee, Patrick C D; Willerth, Stephanie M; Jun, Martin B G

    2014-01-01

    Highly porous poly (ϵ-caprolactone) microfiber scaffolds can be fabricated using electrospinning for tissue engineering applications. Melt electrospinning produces such scaffolds by direct deposition of a polymer melt instead of dissolving the polymer in a solvent as performed during solution electrospinning. The objective of this study was to investigate the significant parameters associated with the melt electrospinning process that influence fiber diameter and scaffold morphology, including processing temperature, collection distance, applied, voltage and nozzle size. The mechanical properties of these microfiber scaffolds varied with microfiber diameter. Additionally, the porosity of scaffolds was determined by combining experimental data with mathematical modeling. To test the cytocompatability of these fibrous scaffolds, we seeded neural progenitors derived from murine R1 embryonic stem cell lines onto these scaffolds, where they could survive, migrate, and differentiate into neurons; demonstrating the potential of these melt electrospun scaffolds for tissue engineering applications.

  7. Fabrication of a Hard Tissue Replacement Using Natural Hydroxyapatite Derived from Bovine Bones by Thermal Decomposition Method

    PubMed Central

    Hosseinzadeh, E.; Davarpanah, M.; Hassanzadeh Nemati, N.; Tavakoli, S. A.

    2014-01-01

    Background: For the treatment of bone defects that exceed the critical size of the injury, several therapies have been investigated. Thermal decomposition method is suggested for extraction of natural hydroxyapatite bioceramic (HA). This technique in comparison with other methods of producing HA, has less complexity and greater economic efficiency. Objective: In the present study, a thermal decomposition method is suggested for extraction of natural HA from bovine femur bones. Methods: In this experiment, to extract the ceramic material, the bone samples were first de-fatted and ground to particles less than 420 μm, and also 420–500 μm, respectively. Prepared powders were heated at 170 °C for 24 h, and then divided into two groups for 6 h. The first group was heated at 750 °C; the second group was heated at 850 °C. The calcium phosphate compounds were obtained with complete elimination of the organic phase of the bone. These bioceramic compounds were characterized physiochemically by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), and scanning electron microscopy (SEM). Results: We found that the powder heated at 750 °C in two dimensional scales was rich in carbonated hydroxyapatite, and therefore, eminently suitable for using in hard tissue replacements. However, increasing the temperature up to 850 °C reduced the Ca/P ratio to 1.5 in the powder sample sizes less than 420 μm. Consequently, the obtained composition became rather similar to the chemical formula of tricalcium phosphate (TCP) that is appropriate in tissue engineering and drug delivery applications. Conclusion: The observations affirmed that by eliminating the collagen and other organic materials existing in the bovine bones, the mineral phase of the bone had the potential of transformation to nano-particles. To investigate the repair of critical-size bone defects and bone augmentation, cylindrical blocks were fabricated by applying

  8. Rapid fabrication of poly(DL-lactide) nanofiber scaffolds with tunable degradation for tissue engineering applications by air-brushing

    PubMed Central

    Behrens, Adam M; Kim, Jeffrey; Hotaling, Nathan; Seppala, Jonathan E; Kofinas, Peter; Tutak, Wojtek

    2016-01-01

    Polymer nanofiber based materials have been widely investigated for use as tissue engineering scaffolds. While promising, these materials are typically fabricated through techniques that require significant time or cost. Here we report a rapid and cost effective air-brushing method for fabricating nanofiber scaffolds using a simple handheld apparatus, compressed air, and a polymer solution. Air-brushing also facilities control over the scaffold degradation rate without adversely impacting architecture. This was accomplished through a one step blending process of high (Mw ≈ 100 000 g mol−1) and low (Mw ≈ 25 000 g mol−1) molecular weight poly(DL-lactide) (PDLLA) polymers at various ratios (100:0, 70:30 and 50:50). Through this approach, we were able to control fiber scaffold degradation rate while maintaining similar fiber morphology, scaffold porosity, and bulk mechanical properties across all of the tested compositions. The impact of altered degradation rates was biologically evaluated in human bone marrow stromal cell (hBMSC) cultures for up to 16 days and demonstrated degradation rate dependence of both total DNA concentration and gene regulation. PMID:27121660

  9. Rapid fabrication of poly(DL-lactide) nanofiber scaffolds with tunable degradation for tissue engineering applications by air-brushing.

    PubMed

    Behrens, Adam M; Kim, Jeffrey; Hotaling, Nathan; Seppala, Jonathan E; Kofinas, Peter; Tutak, Wojtek

    2016-01-01

    Polymer nanofiber based materials have been widely investigated for use as tissue engineering scaffolds. While promising, these materials are typically fabricated through techniques that require significant time or cost. Here we report a rapid and cost effective air-brushing method for fabricating nanofiber scaffolds using a simple handheld apparatus, compressed air, and a polymer solution. Air-brushing also facilities control over the scaffold degradation rate without adversely impacting architecture. This was accomplished through a one step blending process of high (M w  ≈  100 000 g mol(-1)) and low (M w  ≈  25 000 g mol(-1)) molecular weight poly(DL-lactide) (PDLLA) polymers at various ratios (100:0, 70:30 and 50:50). Through this approach, we were able to control fiber scaffold degradation rate while maintaining similar fiber morphology, scaffold porosity, and bulk mechanical properties across all of the tested compositions. The impact of altered degradation rates was biologically evaluated in human bone marrow stromal cell (hBMSC) cultures for up to 16 days and demonstrated degradation rate dependence of both total DNA concentration and gene regulation. PMID:27121660

  10. Biomimetic nanofibrous scaffolds for bone tissue engineering

    PubMed Central

    Holzwarth, Jeremy M.; Ma, Peter X.

    2011-01-01

    Bone tissue engineering is a highly interdisciplinary field that seeks to tackle the most challenging bone-related clinical issues. The major components of bone tissue engineering are the scaffold, cells, and growth factors. This review will focus on the scaffold and recent advancements in developing scaffolds that can mimic the natural extracellular matrix of bone. Specifically, these novel scaffolds mirror the nanofibrous collagen network that comprises the majority of the non-mineral portion of bone matrix. Using two main fabrication techniques, electrospinning and thermally-induced phase separation, and incorporating bone-like minerals, such as hydroxyapatite, composite nanofibrous scaffolds can improve cell adhesion, stem cell differentiation, and tissue formation. This review will cover the two main processing techniques and how they are being applied to fabricate scaffolds for bone tissue engineering. It will then cover how these scaffolds can enhance the osteogenic capabilities of a variety of cell types and survey the ability of the constructs to support the growth of clinically relevant bone tissue. PMID:21944829

  11. Polymer scaffolds with no skin-effect for tissue engineering applications fabricated by thermally induced phase separation.

    PubMed

    Kasoju, Naresh; Kubies, Dana; Sedlačík, Tomáš; Janoušková, Olga; Koubková, Jana; Kumorek, Marta M; Rypáček, František

    2016-01-11

    Thermally induced phase separation (TIPS) based methods are widely used for the fabrication of porous scaffolds for tissue engineering and related applications. However, formation of a less-/non-porous layer at the scaffold's outer surface at the air-liquid interface, often known as the skin-effect, restricts the cell infiltration inside the scaffold and therefore limits its efficacy. To this end, we demonstrate a TIPS-based process involving the exposure of the just quenched poly(lactide-co-caprolactone):dioxane phases to the pure dioxane for a short time while still being under the quenching strength, herein after termed as the second quenching (2Q). Scanning electron microscopy, mercury intrusion porosimetry and contact angle analysis revealed a direct correlation between the time of 2Q and the gradual disappearance of the skin, followed by the widening of the outer pores and the formation of the fibrous filaments over the surface, with no effect on the internal pore architecture and the overall porosity of scaffolds. The experiments at various quenching temperatures and polymer concentrations revealed the versatility of 2Q in removing the skin. In addition, the in vitro cell culture studies with the human primary fibroblasts showed that the scaffolds prepared by the TIPS based 2Q process, with the optimal exposure time, resulted in a higher cell seeding and viability in contrast to the scaffolds prepared by the regular TIPS. Thus, TIPS including the 2Q step is a facile, versatile and innovative approach to fabricate the polymer scaffolds with a skin-free and fully open porous surface morphology for achieving a better cell response in tissue engineering and related applications.

  12. Fabrication of a nanofibrous scaffold with improved bioactivity for culture of human dermal fibroblasts for skin regeneration.

    PubMed

    Chandrasekaran, Arun Richard; Venugopal, J; Sundarrajan, S; Ramakrishna, S

    2011-02-01

    Engineering dermal substitutes with electrospun nanofibres have lately been of prime importance for skin tissue regeneration. Simple electrospinning technology served to produce nanofibrous scaffolds morphologically and structurally similar to the extracellular matrix of native tissues. The nanofibrous scaffolds of poly(L-lactic acid)-co-poly(ε-caprolactone) (PLACL) and PLACL/gelatin complexes were fabricated by the electrospinning process. These nanofibres were characterized for fibre morphology, membrane porosity, wettability and chemical properties by FTIR analysis to culture human foreskin fibroblasts for skin tissue engineering. The nanofibre diameter was obtained between 282 and 761 nm for PLACL and PLACL/gelatin scaffolds; expressions of amino and carboxyl groups and porosity up to 87% were obtained for these fibres, while they also exhibited improved hydrophilic properties after plasma treatment. The results showed that fibroblasts proliferation, morphology, CMFDA dye expression and secretion of collagen were significantly increased in plasma-treated PLACL/gelatin scaffolds compared to PLACL nanofibrous scaffolds. The obtained results prove that the plasma-treated PLACL/gelatin nanofibrous scaffold is a potential biocomposite material for skin tissue regeneration. PMID:21205999

  13. Self-reinforced composites of hydroxyapatite-coated PLLA fibers: fabrication and mechanical characterization.

    PubMed

    Charles, Lyndon F; Kramer, Erica R; Shaw, Montgomery T; Olson, James R; Wei, Mei

    2013-01-01

    Self-reinforced composites (SRCs) are materials where both the matrix and fiber-reinforcing phase are made up of the same polymer. Improved bonding can be achieved with self-reinforced composites compared to traditional dual-polymer, fiber-reinforced composites owing to the identical chemistry of the components in SRCs. Bonding between the fiber and matrix phase is an important factor in applications where mechanical stability is required, such as in the field of bone repair. In this study, we prepared bioabsorbable poly(L-lactic acid)/hydroxyapatite (PLLA/HA) self-reinforced composites via a three-step process that includes surface etching of the fiber, the deposition of the HA coating onto the PLLA fibers through immersion in simulated body fluid (SBF), and hot compaction molding. Although coated with a layer of HA, self-reinforced composites were successfully generated by hot compaction. The effects of compaction time (15 and 30 min), compaction temperature (140, 150, 155, 160, 165, and 170 °C), and HA wt% (0, 5, 10, and 15 wt%) on flexural mechanical properties were studied. Mechanical test results indicated that in unfilled (no HA) PLLA SRCs, compaction time and temperature increased the flexural modulus of the composites tested. Based on the results obtained for unfilled composites, a single compaction time and temperature condition of 15 min and 170 °C were selected to study the effect of HA loading on the composite mechanical properties. HA was successfully loaded onto the fibers at 0, 5, 10, and 15 wt% before hot compaction and was found to significantly increase flexural modulus (P=0.0001). Modulus values ranged from 8.3 GPa±0.5 (0 wt% HA) to 9.7 GPa±0.6 (15 wt% HA). Microscopy results suggest that the HA in these composites forms a nodular-like structure along the fibers, which allows polymer-polymer contact yet prevents longitudinal shear. The procedure used successfully generated composites with flexural moduli near the lower range of bone that may

  14. The role of hydroxyapatite as solid signal on performance of PCL porous scaffolds for bone tissue regeneration.

    PubMed

    Guarino, Vincenzo; Causa, Filippo; Netti, Paolo A; Ciapetti, Gabriela; Pagani, Stefania; Martini, Desiree; Baldini, Nicola; Ambrosio, Luigi

    2008-08-01

    Highly porous composites made up of biodegradable poly-epsilon-caprolactone (PCL) and stoichiometric hydroxyapatite (HA) particles have been developed as substrate for bone-tissue regeneration. The processing technique consists of phase inversion and particulate (salt crystals) leaching. Three different HA contents (13, 20 and 26 vol %) in PCL-based composite were considered in this study. Pore microstructure with fully interconnected network and pore sizes ranging around a few hundred of mum (macroporosity) was obtained as a result of salt particles removal by leaching process. Several microns (microporosity) porosity was also created through phase inversion of polymer solution. Total porosity up to 95% was achieved. Human marrow stromal cells (MSC) were seeded onto porous PCL-based composites for 1-5 weeks and cultured in osteogenic medium. MSC were able to adhere and grow on PCL-based substrates with a plateau at 3-4 weeks. However, the small effect of bioactive signals on the biological response evaluated in MSC cell culture suggests a prior role of topography on the biological response. Importantly, the presence of HA as a bioactive solid signal determines an increase of mechanical properties. On the overall, the results indicated that porous PCL-based composites are potential candidate for bone substitution with beneficial influence on structural characteristics by solid signal addition.

  15. Adhesion between biodegradable polymers and hydroxyapatite: Relevance to synthetic bone-like materials and tissue engineering scaffolds.

    PubMed

    Neuendorf, R E; Saiz, E; Tomsia, A P; Ritchie, R O

    2008-09-01

    Many studies are currently underway on the quest to make synthetic bone-like materials with composites of polymeric materials and hydroxyapatite (HA). In the present work, we use wetting experiments and surface tension measurements to determine the work of adhesion between biodegradable polymers and HA, with specific reference to the role of humid environments. All the polymers are found to exhibit low contact angles (

  16. Indigenous hydroxyapatite coated and bioactive glass coated titanium dental implant system – Fabrication and application in humans

    PubMed Central

    Mistry, Surajit; Kundu, Debabrata; Datta, Someswar; Basu, Debabrata; Soundrapandian, Chidambaram

    2011-01-01

    Background: The use of different bioactive materials as coating on dental implant to restore tooth function is a growing trend in modern Dentistry. In the present study, hydroxyapatite and the bioactive glass-coated implants were evaluated for their behavior in osseous tissue following implantation in 14 patients. Materials and Methods: Bioactive glass and hydroxyapatite formulated and prepared for coating on Ti-6Al-4V alloy. Hydroxyapatite coating was applied on the implant surface by air plasma spray technique and bioactive glass coating was applied by vitreous enameling technique. Their outcome was assessed after 6 months in vivo study in human. Results: Hydroxyapatite and bioactive glass coating materials were nontoxic and biocompatible. Uneventful healing was observed with both types of implants. Conclusion: The results showed bioactive glass is a good alternative coating material for dental implant. PMID:22028507

  17. 2007 AIChE Alpha Chi Sigma Award: From Material to Tissue: Biomaterial Development, Scaffold Fabrication, and Tissue Engineering

    PubMed Central

    Kretlow, James D.; Mikos, Antonios G.

    2009-01-01

    The need for techniques to facilitate the regeneration of failing or destroyed tissues remains great with the aging of the worldwide population and the continued incidence of trauma and diseases such as cancer. A 16-year history in biomaterial scaffold development and tissue engineering is examined, beginning with the synthesis of novel materials and fabrication of 3D porous scaffolds. Exploring cell-scaffold interactions and subsequently cellular delivery using biomaterial carriers, we have developed a variety of techniques for bone and cartilage engineering. In addition to delivering cells, we have utilized growth factors, DNA, and peptides to improve the in vitro and in vivo regeneration of tissues. This review covers important developments and discoveries within our laboratory, and the increasing breadth in the scope of our work within the expanding field of tissue engineering is presented. PMID:19756176

  18. A novel approach to fabricate silk nanofibers containing hydroxyapatite nanoparticles using a three-way stopcock connector

    NASA Astrophysics Data System (ADS)

    Sheikh, Faheem A.; Ju, Hyung Woo; Moon, Bo Mi; Park, Hyun Jung; Kim, Jung Ho; Lee, Ok Joo; Park, Chan Hum

    2013-07-01

    Electrospinning technique is commonly used to produce micro- and/or nanofibers, which utilizes electrical forces to produce polymeric fibers with diameters ranging from several micrometers down to few nanometers. Desirably, electrospun materials provide highly porous structure and appropriate pore size for initial cell attachment and proliferation and thereby enable the exchange of nutrients. Composite nanofibers consisting of silk and hydroxyapatite nanoparticles (HAp) (NPs) had been considered as an excellent choice due to their efficient biocompatibility and bone-mimicking properties. To prepare these nanofiber composites, it requires the use of acidic solutions which have serious consequences on the nature of both silk and HAp NPs. It is ideal to create these nanofibers using aqueous solutions in which the physicochemical nature of both materials can be retained. However, to create those nanofibers is often difficult to obtain because of the fact that aqueous solutions of silk and HAp NPs can precipitate before they can be ejected into fibers during the electrospinning process. In this work, we had successfully used a three-way stopcock connector to mix the two different solutions, and very shortly, this solution is ejected out to form nanofibers due to electric fields. Different blend ratios consisting HAp NPs had been electrospun into nanofibers. The physicochemical aspects of fabricated nanofiber had been characterized by different state of techniques like that of FE-SEM, EDS, TEM, TEM-EDS, TGA, FT-IR, and XRD. These characterization techniques revealed that HAp NPs can be easily introduced in silk nanofibers using a stopcock connector, and this method favorably preserves the intact nature of silk fibroin and HAp NPs. Moreover, nanofibers obtained by this strategy were tested for cell toxicity and cell attachment studies using NIH 3 T3 fibroblasts which indicated non-toxic behavior and good attachment of cells upon incubation in the presence of nanofibers.

  19. A novel approach to fabricate silk nanofibers containing hydroxyapatite nanoparticles using a three-way stopcock connector.

    PubMed

    Sheikh, Faheem A; Ju, Hyung Woo; Moon, Bo Mi; Park, Hyun Jung; Kim, Jung Ho; Lee, Ok Joo; Park, Chan Hum

    2013-01-01

    Electrospinning technique is commonly used to produce micro- and/or nanofibers, which utilizes electrical forces to produce polymeric fibers with diameters ranging from several micrometers down to few nanometers. Desirably, electrospun materials provide highly porous structure and appropriate pore size for initial cell attachment and proliferation and thereby enable the exchange of nutrients. Composite nanofibers consisting of silk and hydroxyapatite nanoparticles (HAp) (NPs) had been considered as an excellent choice due to their efficient biocompatibility and bone-mimicking properties. To prepare these nanofiber composites, it requires the use of acidic solutions which have serious consequences on the nature of both silk and HAp NPs. It is ideal to create these nanofibers using aqueous solutions in which the physicochemical nature of both materials can be retained. However, to create those nanofibers is often difficult to obtain because of the fact that aqueous solutions of silk and HAp NPs can precipitate before they can be ejected into fibers during the electrospinning process. In this work, we had successfully used a three-way stopcock connector to mix the two different solutions, and very shortly, this solution is ejected out to form nanofibers due to electric fields. Different blend ratios consisting HAp NPs had been electrospun into nanofibers. The physicochemical aspects of fabricated nanofiber had been characterized by different state of techniques like that of FE-SEM, EDS, TEM, TEM-EDS, TGA, FT-IR, and XRD. These characterization techniques revealed that HAp NPs can be easily introduced in silk nanofibers using a stopcock connector, and this method favorably preserves the intact nature of silk fibroin and HAp NPs. Moreover, nanofibers obtained by this strategy were tested for cell toxicity and cell attachment studies using NIH 3 T3 fibroblasts which indicated non-toxic behavior and good attachment of cells upon incubation in the presence of nanofibers

  20. Tailor-made biopolymers porous scaffold fabrication for tissue engineering: application of radiant energy in the form of microwave under vacuum.

    PubMed

    Jaya, S; Durance, T D

    2008-01-01

    Many methods are available for developing three-dimensional porous scaffolds using various polymeric materials for tissue-engineering applications. Each has its own advantages and disadvantages. Some of the available methods and their limitations were discussed briefly. This paper focuses on the scope of novel technology called radiant energy application under vacuum for the fabrication of three-dimensional porous scaffolds for tissue engineering applications. Radiant energy application in the form of microwave under vacuum has been shown to develop and maintain the porous structure in fruits and vegetables after dehydration, which produced the microstructure similar to the freeze dried materials. Same principle of applying radiant energy under vacuum was used on the biopolymeric gels to create tailor-made, porous scaffolds for biomedical purposes. It has many advantages over the other existing methods of scaffold fabrication. This paper also reviews the scaffolds design recently fabricated by the authors using radiant energy under vacuum.

  1. Carbon nanotube (CNT) and nanofibrillated cellulose (NFC) reinforcement effect on thermoplastic polyurethane (TPU) scaffolds fabricated via phase separation using dimethyl sulfoxide (DMSO) as solvent.

    PubMed

    Mi, Hao-Yang; Jing, Xin; Salick, Max R; Cordie, Travis M; Turng, Lih-Sheng

    2016-09-01

    Although phase separation is a simple method of preparing tissue engineering scaffolds, it suffers from organic solvent residual in the scaffold. Searching for nontoxic solvents and developing effective solvent removal methods are current challenges in scaffold fabrication. In this study, thermoplastic polyurethane (TPU) scaffolds containing carbon nanotubes (CNTs) or nanofibrillated cellulose fibers (NFCs) were prepared using low toxicity dimethyl sulfoxide (DMSO) as a solvent. The effects of two solvent removal approaches on the final scaffold morphology were studied. The freeze drying method caused large pores, with small pores on the pore walls, which created connections between the pores. Meanwhile, the leaching and freeze drying method led to interconnected fine pores with smaller pore diameters. The nucleation effect of CNTs and the phase separation behavior of NFCs in the TPU solution resulted in significant differences in the microstructures of the resulting scaffolds. The mechanical performance of the nanocomposite scaffolds with different morphologies was investigated. Generally, the scaffolds with a fine pore structure showed higher compressive properties, and both the CNTs and NFCs improved the compressive properties of the scaffolds, with greater enhancement found in TPU/NFC nanocomposite scaffolds. In addition, all scaffolds showed good sustainability under cyclical load bearing, and the biocompatibility of the scaffolds was verified via 3T3 fibroblast cell culture. PMID:27266475

  2. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    PubMed Central

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100–150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1–10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications. PMID:26782020

  3. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects.

    PubMed

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  4. Design and Fabrication of 3D printed Scaffolds with a Mechanical Strength Comparable to Cortical Bone to Repair Large Bone Defects

    NASA Astrophysics Data System (ADS)

    Roohani-Esfahani, Seyed-Iman; Newman, Peter; Zreiqat, Hala

    2016-01-01

    A challenge in regenerating large bone defects under load is to create scaffolds with large and interconnected pores while providing a compressive strength comparable to cortical bone (100-150 MPa). Here we design a novel hexagonal architecture for a glass-ceramic scaffold to fabricate an anisotropic, highly porous three dimensional scaffolds with a compressive strength of 110 MPa. Scaffolds with hexagonal design demonstrated a high fatigue resistance (1,000,000 cycles at 1-10 MPa compressive cyclic load), failure reliability and flexural strength (30 MPa) compared with those for conventional architecture. The obtained strength is 150 times greater than values reported for polymeric and composite scaffolds and 5 times greater than reported values for ceramic and glass scaffolds at similar porosity. These scaffolds open avenues for treatment of load bearing bone defects in orthopaedic, dental and maxillofacial applications.

  5. In situ cross-linked electrospun fiber scaffold of collagen for fabricating cell-dense muscle tissue.

    PubMed

    Takeda, Naoya; Tamura, Kenichi; Mineguchi, Ryo; Ishikawa, Yumiko; Haraguchi, Yuji; Shimizu, Tatsuya; Hara, Yusuke

    2016-06-01

    Engineered muscle tissues used as transplant tissues in regenerative medicine should have a three-dimensional and cell-dense structure like native tissue. For fabricating a 3D cell-dense muscle tissue from myoblasts, we proposed the electrospun type I collagen microfiber scaffold of the string-shape like a harp. The microfibers were oriented in the same direction to allow the myoblasts to align, and were strung at low density with micrometer intervals to create space for the cells to occupy. To realize this shape of the scaffold, we employed in situ cross-linking during electrospinning process for the first time to collagen fibers. The collagen microfibers in situ cross-linked with glutaraldehyde stably existed in the aqueous media and completely retained the original shape to save the spaces between the fibers for over 14 days. On the contrary, the conventional cross-linking method by exposure to a glutaraldehyde aqueous solution vapor partially dissolved and damaged the fiber to lose a low-density shape of the scaffold. Myoblasts could penetrate into the interior of the in situ cross-linked string-shaped scaffold and form the cell-dense muscle tissues. Histochemical analysis showed the total area occupied by the cells in the cross section of the tissue was approximately 73 %. Furthermore, the resulting muscle tissue fabricated from primary myoblasts showed typical sarcomeric cross-striations and the entire tissue continuously pulsated by autonomous contraction. Together with the in situ cross-linking, the string-shaped scaffold provides an efficient methodology to fabricate a cell-dense 3D muscle tissue, which could be applied in regenerative medicine in future. PMID:26472433

  6. The fabrication of double layer tubular vascular tissue engineering scaffold via coaxial electrospinning and its 3D cell coculture.

    PubMed

    Ye, Lin; Cao, Jie; Chen, Lamei; Geng, Xue; Zhang, Ai-Ying; Guo, Lian-Rui; Gu, Yong-Quan; Feng, Zeng-Guo

    2015-12-01

    A continuous electrospinning technique was applied to fabricate double layer tubular tissue engineering vascular graft (TEVG) scaffold. The luminal layer was made from poly(ɛ-caprolac-tone)(PCL) ultrafine fibers via common single axial electrospinning followed by the outer layer of core-shell structured nanofibers via coaxial electrospinning. For preparing the outer layernano-fibers, the PCL was electrospun into the shell and both bovine serum albumin (BSA) and tetrapeptide val-gal-pro-gly (VAPG) were encapsulated into the core. The core-shell structure in the outer layer fibers was observed by transmission electron microscope (TEM). The in vitro release tests exhibited the sustainable release behavior of BSA and VAPG so that they provided a better cell growth environment in the interior of tubular scaffold wall. The in vitro culture of smooth muscle cells (SMCs) demonstrated their potential to penetrate into the scaffold wall for the 3D cell culture. Subsequently, 3D cell coculture was conducted. First, SMCs were seeded on the luminal surface of the scaffold and cultured for 5 days, and then endothelial cells (ECs) were also seeded on the luminal surface and cocultured with SMCs for another 2 days. After stained with antibodies, 3D cell distribution on the scaffold was revealed by confocal laser scanning microscopy (CLSM) where ECs were mainly located on the luminal surface whereas SMCs penetrated into the surface and distributed inside the scaffold wall. This double layer tubular scaffold with 3D cell distribution showed the promise to develop it into a novel TEVG for clinical trials in the near future.

  7. Fabrication of multilayer ZrO₂-biphasic calcium phosphate-poly-caprolactone unidirectional channeled scaffold for bone tissue formation.

    PubMed

    Mondal, Dibakar; So-Ra, Son; Sarkar, Swapan Kumar; Min, Young Ki; Yang, Hun Mo; Lee, Byong Taek

    2013-09-01

    We developed a continuously porous scaffold with laminated matrix and bone-like microstructure by a multi-pass extrusion process. In this scaffold, tetragonal ZrO₂, biphasic calcium phosphate and poly-caprolactone layers were arranged in a co-axially laminated unit cell with a channel in the center. The entire matrix phase had a laminated microstructure of alternate lamina of tetragonal ZrO₂, biphasic calcium phosphate and poly-caprolactone--biphasic calcium phosphate with optimized designed thickness and channeled porosity. Each of the continuous pores was coaxially encircled by the poly-caprolactone--biphasic calcium phosphate layer, biphasic calcium phosphate layer and finally tetragonal ZrO₂ layer, one after the other. Before extrusion, 5 vol% graphite powder was mixed with tetragonal ZrO₂ to ensure pores in the outer layer and connectivity among the lamellas. The design strategy is aimed to incorporate a lamellar microstructure like the natural bone in the macro-scaled ceramic body to investigate the strengthening phenomenon and pave the way for fabricating complex microstructure of natural bone could be applied for whole bone replacement. The final fabricated scaffold had a compressive strength of 12.7 MPa and porosity of 78 vol% with excellent cell viability, cell attachment and osteocalcin and collagen expression from cultured MG63 cells on scaffold.

  8. Materials and fabrication of electrode scaffolds for deposition of MnO2 and their true performance in supercapacitors

    NASA Astrophysics Data System (ADS)

    Cao, Jianyun; Li, Xiaohong; Wang, Yaming; Walsh, Frank C.; Ouyang, Jia-Hu; Jia, Dechang; Zhou, Yu

    2015-10-01

    MnO2 is a promising electrode material for high energy supercapacitors because of its large pseudo-capacitance. However, MnO2 suffers from low electronic conductivity and poor cation diffusivity, which results in poor utilization and limited rate performance of traditional MnO2 powder electrodes, obtained by pressing a mixed paste of MnO2 powder, conductive additive and polymer binder onto metallic current collectors. Developing binder-free MnO2 electrodes by loading nanoscale MnO2 deposits on pre-fabricated device-ready electrode scaffolds is an effective way to achieve both high power and energy performance. These electrode scaffolds, with interconnected skeletons and pore structures, will not only provide mechanical support and electron collection as traditional current collectors but also fast ion transfer tunnels, leading to high MnO2 utilization and rate performance. This review covers design strategies, materials and fabrication methods for the electrode scaffolds. Rational evaluation of the true performance of these electrodes is carried out, which clarifies that some of the electrodes with as-claimed exceptional performances lack potential in practical applications due to poor mass loading of MnO2 and large dead volume of inert scaffold materials/void spaces in the electrode structure. Possible ways to meet this challenge and bring MnO2 electrodes from laboratory studies to real-world applications are considered.

  9. Numerical investigation of the mechanical properties of the additive manufactured bone scaffolds fabricated by FDM: The effect of layer penetration and post-heating.

    PubMed

    Naghieh, S; Karamooz Ravari, M R; Badrossamay, M; Foroozmehr, E; Kadkhodaei, M

    2016-06-01

    In recent years, thanks to additive manufacturing technology, researchers have gone towards the optimization of bone scaffolds for the bone reconstruction. Bone scaffolds should have appropriate biological as well as mechanical properties in order to play a decisive role in bone healing. Since the fabrication of scaffolds is time consuming and expensive, numerical methods are often utilized to simulate their mechanical properties in order to find a nearly optimum one. Finite element analysis is one of the most common numerical methods that is used in this regard. In this paper, a parametric finite element model is developed to assess the effects of layers penetration׳s effect on inter-layer adhesion, which is reflected on the mechanical properties of bone scaffolds. To be able to validate this model, some compression test specimens as well as bone scaffolds are fabricated with biocompatible and biodegradable poly lactic acid using fused deposition modeling. All these specimens are tested in compression and their elastic modulus is obtained. Using the material parameters of the compression test specimens, the finite element analysis of the bone scaffold is performed. The obtained elastic modulus is compared with experiment indicating a good agreement. Accordingly, the proposed finite element model is able to predict the mechanical behavior of fabricated bone scaffolds accurately. In addition, the effect of post-heating of bone scaffolds on their elastic modulus is investigated. The results demonstrate that the numerically predicted elastic modulus of scaffold is closer to experimental outcomes in comparison with as-built samples.

  10. Numerical investigation of the mechanical properties of the additive manufactured bone scaffolds fabricated by FDM: The effect of layer penetration and post-heating.

    PubMed

    Naghieh, S; Karamooz Ravari, M R; Badrossamay, M; Foroozmehr, E; Kadkhodaei, M

    2016-06-01

    In recent years, thanks to additive manufacturing technology, researchers have gone towards the optimization of bone scaffolds for the bone reconstruction. Bone scaffolds should have appropriate biological as well as mechanical properties in order to play a decisive role in bone healing. Since the fabrication of scaffolds is time consuming and expensive, numerical methods are often utilized to simulate their mechanical properties in order to find a nearly optimum one. Finite element analysis is one of the most common numerical methods that is used in this regard. In this paper, a parametric finite element model is developed to assess the effects of layers penetration׳s effect on inter-layer adhesion, which is reflected on the mechanical properties of bone scaffolds. To be able to validate this model, some compression test specimens as well as bone scaffolds are fabricated with biocompatible and biodegradable poly lactic acid using fused deposition modeling. All these specimens are tested in compression and their elastic modulus is obtained. Using the material parameters of the compression test specimens, the finite element analysis of the bone scaffold is performed. The obtained elastic modulus is compared with experiment indicating a good agreement. Accordingly, the proposed finite element model is able to predict the mechanical behavior of fabricated bone scaffolds accurately. In addition, the effect of post-heating of bone scaffolds on their elastic modulus is investigated. The results demonstrate that the numerically predicted elastic modulus of scaffold is closer to experimental outcomes in comparison with as-built samples. PMID:26874065

  11. Effect of pore architecture and stacking direction on mechanical properties of solid freeform fabrication-based scaffold for bone tissue engineering.

    PubMed

    Lee, Jung-Seob; Cha, Hwang Do; Shim, Jin-Hyung; Jung, Jin Woo; Kim, Jong Young; Cho, Dong-Woo

    2012-07-01

    Fabrication of a three-dimensional (3D) scaffold with increased mechanical strength may be an essential requirement for more advanced bone tissue engineering scaffolds. Various material- and chemical-based approaches have been explored to enhance the mechanical properties of engineered bone tissue scaffolds. In this study, the effects of pore architecture and stacking direction on the mechanical and cell proliferation properties of a scaffold were investigated. The 3D scaffold was prepared using solid freeform fabrication technology with a multihead deposition system. Various types of scaffolds with different pore architectures (lattice, stagger, and triangle types) and stacking directions (horizontal and vertical directions) were fabricated with a blend of polycaprolactone and poly lactic-co-glycolic acid. In compression tests, the triangle-type scaffold was the strongest among the experimental groups. Stacking direction affected the mechanical properties of scaffolds. An in vitro cell counting kit-8 assay showed no significant differences in optical density depending on the different pore architectures and stacking directions. In conclusion, mechanical properties of scaffolds can be enhanced by controlling pore architecture and stacking direction.

  12. In-vitro degradation characteristics of poly(e-caprolactone)/poly(glycolic acid) scaffolds fabricated via solid-state cryomilling.

    PubMed

    Jonnalagadda, John B; Rivero, Iris V; Warzywoda, Juliusz

    2015-10-01

    Poly(e-caprolactone) (PCL)/poly(glycolic acid) (PGA) scaffolds were fabricated via solid-state cryomilling along with compression molding and porogen leaching techniques. Four types of scaffolds were produced using four distinct cryomilling times. These scaffolds were evaluated for their in-vitro degradation behavior hydrolytically in phosphate buffer saline (PBS). The degradation profiles were investigated over a period of 60 days. The percentage of weight loss, percentage of water absorption, morphology, compressive, thermal, and material properties were studied as a function of degradation time. Weight loss and water absorption demonstrated a high correlation, which showed an increasing behavior with increase in cryomilling time and degradation time. Morphology of the scaffolds analyzed through scanning electron microscopy (SEM) revealed micro-cracks on the surface of the cylindrical struts due to hydrolytic attack and dissolution of hydrophilic PGA. Changes in compressive modulus and crystallinity over the degradation period and material properties were analyzed using X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. DSC and XRD results indicated that hydrolytic attack had taken place during degradation, resulting in moments of increased and decreased percent crystallinity. This study successfully brought forth the differences in resultant properties of the PCL/PGA scaffolds as a function of degradation time.

  13. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.

    PubMed

    Mi, Hao-Yang; Salick, Max R; Jing, Xin; Jacques, Brianna R; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

    2013-12-01

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications.

  14. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.

    PubMed

    Mi, Hao-Yang; Salick, Max R; Jing, Xin; Jacques, Brianna R; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

    2013-12-01

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. PMID:24094186

  15. Bioinspired double polysaccharides-based nanohybrid scaffold for bone tissue engineering.

    PubMed

    Fan, Tiantang; Chen, Jingdi; Pan, Panpan; Zhang, Yujue; Hu, Yimin; Liu, Xiaocui; Shi, Xuetao; Zhang, Qiqing

    2016-11-01

    The fabrication of bone scaffolds with interconnected porous structure, adequate mechanical properties and excellent biocompatibility presents a great challenge. Herein, a hybrid nanostructured chitosan/chondroitin sulfate/hydroxyapatite (ChS/CSA/HAP) in situ composite scaffold was prepared by in situ fabrication and freeze-drying technique. The composition and morphology of scaffold were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). It proved that the low crystallinity of HAP crystals were uniformly distributed in ChS/CSA organic matrix and the nanostructured hybrid scaffold exhibited good mechanical property. The biocompatibility and in vitro bioactivity were detected by MTT-assay, maturation (alkaline phosphatase (ALP) activity), Hoechst 33258 and PI fluorescence staining. In vitro tests indicated that the hybrid scaffold not only promoted the adhesion and proliferation of osteoblasts, but also improved the growth of the osteoblasts. Therefore, it is promising for bone repair application in bone tissue engineering.

  16. Fabrication of electrospun poly(L-lactide-co-ε-caprolactone)/collagen nanoyarn network as a novel, three-dimensional, macroporous, aligned scaffold for tendon tissue engineering.

    PubMed

    Xu, Yuan; Wu, Jinglei; Wang, Haoming; Li, Hanqin; Di, Ning; Song, Lei; Li, Sontao; Li, Dianwei; Xiang, Yang; Liu, Wei; Mo, Xiumei; Zhou, Qiang

    2013-12-01

    Tissue engineering techniques using novel scaffolding materials offer potential alternatives for managing tendon disorders. An ideal tendon tissue engineered scaffold should mimic the three-dimensional (3D) structure of the natural extracellular matrix (ECM) of the native tendon. Here, we propose a novel electrospun nanoyarn network that is morphologically and structurally similar to the ECM of native tendon tissues. The nanoyarn, random nanofiber, and aligned nanofiber scaffolds of a synthetic biodegradable polymer, poly(L-lactide-co-ε-caprolactone) [P(LLA-CL)], and natural collagen I complex were fabricated using electrospinning. These scaffolds were characterized in terms of fiber morphology, pore size, porosity, and chemical and mechanical properties for the purpose of culturing tendon cells (TCs) for tendon tissue engineering. The results indicated a fiber diameter of 632 ± 81 nm for the random nanofiber scaffold, 643 ± 97 nm for the aligned nanofiber scaffold, and 641 ± 68 nm for the nanoyarn scaffold. The yarn in the nanoyarn scaffold was twisted by many nanofibers similar to the structure and inherent nanoscale organization of tendons, indicating an increase in the diameter of 9.51 ± 3.62 μm. The nanoyarn scaffold also contained 3D aligned microstructures with large interconnected pores and high porosity. Fourier transform infrared analyses revealed the presence of collagen in the three scaffolds. The mechanical properties of the sample scaffolds indicated that the scaffolds had desirable mechanical properties for tissue regeneration. Further, the results revealed that TC proliferation and infiltration, and the expression of tendon-related ECM genes, were significantly enhanced on the nanoyarn scaffold compared with that on the random nanofiber and aligned nanofiber scaffolds. This study demonstrates that electrospun P(LLA-CL)/collagen nanoyarn is a novel, 3D, macroporous, aligned scaffold that has potential application in tendon tissue engineering.

  17. Fabrication of Electrospun Poly(L-Lactide-co-ɛ-Caprolactone)/Collagen Nanoyarn Network as a Novel, Three-Dimensional, Macroporous, Aligned Scaffold for Tendon Tissue Engineering

    PubMed Central

    Xu, Yuan; Wu, Jinglei; Wang, Haoming; Li, Hanqin; Di, Ning; Song, Lei; Li, Sontao; Li, Dianwei; Xiang, Yang; Liu, Wei

    2013-01-01

    Tissue engineering techniques using novel scaffolding materials offer potential alternatives for managing tendon disorders. An ideal tendon tissue engineered scaffold should mimic the three-dimensional (3D) structure of the natural extracellular matrix (ECM) of the native tendon. Here, we propose a novel electrospun nanoyarn network that is morphologically and structurally similar to the ECM of native tendon tissues. The nanoyarn, random nanofiber, and aligned nanofiber scaffolds of a synthetic biodegradable polymer, poly(l-lactide-co-ɛ-caprolactone) [P(LLA-CL)], and natural collagen I complex were fabricated using electrospinning. These scaffolds were characterized in terms of fiber morphology, pore size, porosity, and chemical and mechanical properties for the purpose of culturing tendon cells (TCs) for tendon tissue engineering. The results indicated a fiber diameter of 632±81 nm for the random nanofiber scaffold, 643±97 nm for the aligned nanofiber scaffold, and 641±68 nm for the nanoyarn scaffold. The yarn in the nanoyarn scaffold was twisted by many nanofibers similar to the structure and inherent nanoscale organization of tendons, indicating an increase in the diameter of 9.51±3.62 μm. The nanoyarn scaffold also contained 3D aligned microstructures with large interconnected pores and high porosity. Fourier transform infrared analyses revealed the presence of collagen in the three scaffolds. The mechanical properties of the sample scaffolds indicated that the scaffolds had desirable mechanical properties for tissue regeneration. Further, the results revealed that TC proliferation and infiltration, and the expression of tendon-related ECM genes, were significantly enhanced on the nanoyarn scaffold compared with that on the random nanofiber and aligned nanofiber scaffolds. This study demonstrates that electrospun P(LLA-CL)/collagen nanoyarn is a novel, 3D, macroporous, aligned scaffold that has potential application in tendon tissue engineering

  18. Fabrication and characterization of strontium incorporated 3-D bioactive glass scaffolds for bone tissue from biosilica.

    PubMed

    Özarslan, Ali Can; Yücel, Sevil

    2016-11-01

    Bioactive glass scaffolds that contain silica are high viable biomaterials as bone supporters for bone tissue engineering due to their bioactive behaviour in simulated body fluid (SBF). In the human body, these materials help inorganic bone structure formation due to a combination of the particular ratio of elements such as silicon (Si), calcium (Ca), sodium (Na) and phosphorus (P), and the doping of strontium (Sr) into the scaffold structure increases their bioactive behaviour. In this study, bioactive glass scaffolds were produced by using rice hull ash (RHA) silica and commercial silica based bioactive glasses. The structural properties of scaffolds such as pore size, porosity and also the bioactive behaviour were investigated. The results showed that undoped and Sr-doped RHA silica-based bioactive glass scaffolds have better bioactivity than that of commercial silica based bioactive glass scaffolds. Moreover, undoped and Sr-doped RHA silica-based bioactive glass scaffolds will be able to be used instead of undoped and Sr-doped commercial silica based bioactive glass scaffolds for bone regeneration applications. Scaffolds that are produced from undoped or Sr-doped RHA silica have high potential to form new bone for bone defects in tissue engineering.

  19. Fabrication and characterization of strontium incorporated 3-D bioactive glass scaffolds for bone tissue from biosilica.

    PubMed

    Özarslan, Ali Can; Yücel, Sevil

    2016-11-01

    Bioactive glass scaffolds that contain silica are high viable biomaterials as bone supporters for bone tissue engineering due to their bioactive behaviour in simulated body fluid (SBF). In the human body, these materials help inorganic bone structure formation due to a combination of the particular ratio of elements such as silicon (Si), calcium (Ca), sodium (Na) and phosphorus (P), and the doping of strontium (Sr) into the scaffold structure increases their bioactive behaviour. In this study, bioactive glass scaffolds were produced by using rice hull ash (RHA) silica and commercial silica based bioactive glasses. The structural properties of scaffolds such as pore size, porosity and also the bioactive behaviour were investigated. The results showed that undoped and Sr-doped RHA silica-based bioactive glass scaffolds have better bioactivity than that of commercial silica based bioactive glass scaffolds. Moreover, undoped and Sr-doped RHA silica-based bioactive glass scaffolds will be able to be used instead of undoped and Sr-doped commercial silica based bioactive glass scaffolds for bone regeneration applications. Scaffolds that are produced from undoped or Sr-doped RHA silica have high potential to form new bone for bone defects in tissue engineering. PMID:27524030

  20. Fabrication, Characterization and Cellular Compatibility of Poly(Hydroxy Alkanoate) Composite Nanofibrous Scaffolds for Nerve Tissue Engineering

    PubMed Central

    Masaeli, Elahe; Morshed, Mohammad; Nasr-Esfahani, Mohammad Hossein; Sadri, Saeid; Hilderink, Janneke; van Apeldoorn, Aart; van Blitterswijk, Clemens A.; Moroni, Lorenzo

    2013-01-01

    Tissue engineering techniques using a combination of polymeric scaffolds and cells represent a promising approach for nerve regeneration. We fabricated electrospun scaffolds by blending of Poly (3-hydroxybutyrate) (PHB) and Poly (3-hydroxy butyrate-co-3- hydroxyvalerate) (PHBV) in different compositions in order to investigate their potential for the regeneration of the myelinic membrane. The thermal properties of the nanofibrous blends was analyzed by differential scanning calorimetry (DSC), which indicated that the melting and glass temperatures, and crystallization degree of the blends decreased as the PHBV weight ratio increased. Raman spectroscopy also revealed that the full width at half height of the band centered at 1725 cm−1 can be used to estimate the crystalline degree of the electrospun meshes. Random and aligned nanofibrous scaffolds were also fabricated by electrospinning of PHB and PHBV with or without type I collagen. The influence of blend composition, fiber alignment and collagen incorporation on Schwann cell (SCs) organization and function was investigated. SCs attached and proliferated over all scaffolds formulations up to 14 days. SCs grown on aligned PHB/PHBV/collagen fibers exhibited a bipolar morphology that oriented along the fiber direction, while SCs grown on the randomly oriented fibers had a multipolar morphology. Incorporation of collagen within nanofibers increased SCs proliferation on day 14, GDNF gene expression on day 7 and NGF secretion on day 6. The results of this study demonstrate that aligned PHB/PHBV electrospun nanofibers could find potential use as scaffolds for nerve tissue engineering applications and that the presence of type I collagen in the nanofibers improves cell differentiation. PMID:23468923

  1. Cell-Laden Poly(ɛ-caprolactone)/Alginate Hybrid Scaffolds Fabricated by an Aerosol Cross-Linking Process for Obtaining Homogeneous Cell Distribution: Fabrication, Seeding Efficiency, and Cell Proliferation and Distribution

    PubMed Central

    Lee, HyeongJin; Ahn, SeungHyun; Bonassar, Lawrence J.; Chun, Wook

    2013-01-01

    Generally, solid-freeform fabricated scaffolds show a controllable pore structure (pore size, porosity, pore connectivity, and permeability) and mechanical properties by using computer-aided techniques. Although the scaffolds can provide repeated and appropriate pore structures for tissue regeneration, they have a low biological activity, such as low cell-seeding efficiency and nonuniform cell density in the scaffold interior after a long culture period, due to a large pore size and completely open pores. Here we fabricated three different poly(ɛ-caprolactone) (PCL)/alginate scaffolds: (1) a rapid prototyped porous PCL scaffold coated with an alginate, (2) the same PCL scaffold coated with a mixture of alginate and cells, and (3) a multidispensed hybrid PCL/alginate scaffold embedded with cell-laden alginate struts. The three scaffolds had similar micropore structures (pore size=430–580 μm, porosity=62%–68%, square pore shape). Preosteoblast cells (MC3T3-E1) were used at the same cell density in each scaffold. By measuring cell-seeding efficiency, cell viability, and cell distribution after various periods of culturing, we sought to determine which scaffold was more appropriate for homogeneously regenerated tissues. PMID:23469894

  2. Cell-laden poly(ɛ-caprolactone)/alginate hybrid scaffolds fabricated by an aerosol cross-linking process for obtaining homogeneous cell distribution: fabrication, seeding efficiency, and cell proliferation and distribution.

    PubMed

    Lee, HyeongJin; Ahn, SeungHyun; Bonassar, Lawrence J; Chun, Wook; Kim, GeunHyung

    2013-10-01

    Generally, solid-freeform fabricated scaffolds show a controllable pore structure (pore size, porosity, pore connectivity, and permeability) and mechanical properties by using computer-aided techniques. Although the scaffolds can provide repeated and appropriate pore structures for tissue regeneration, they have a low biological activity, such as low cell-seeding efficiency and nonuniform cell density in the scaffold interior after a long culture period, due to a large pore size and completely open pores. Here we fabricated three different poly(ɛ-caprolactone) (PCL)/alginate scaffolds: (1) a rapid prototyped porous PCL scaffold coated with an alginate, (2) the same PCL scaffold coated with a mixture of alginate and cells, and (3) a multidispensed hybrid PCL/alginate scaffold embedded with cell-laden alginate struts. The three scaffolds had similar micropore structures (pore size = 430-580 μm, porosity = 62%-68%, square pore shape). Preosteoblast cells (MC3T3-E1) were used at the same cell density in each scaffold. By measuring cell-seeding efficiency, cell viability, and cell distribution after various periods of culturing, we sought to determine which scaffold was more appropriate for homogeneously regenerated tissues.

  3. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing.

    PubMed

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C-1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C-1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds were

  4. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing.

    PubMed

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C-1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C-1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds were

  5. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing

    PubMed Central

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C–1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C–1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds

  6. Effect of bioactive borate glass microstructure on bone regeneration, angiogenesis, and hydroxyapatite conversion in a rat calvarial defect model.

    PubMed

    Bi, Lianxiang; Rahaman, Mohamed N; Day, Delbert E; Brown, Zackary; Samujh, Christopher; Liu, Xin; Mohammadkhah, Ali; Dusevich, Vladimir; Eick, J David; Bonewald, Lynda F

    2013-08-01

    Borate bioactive glasses are biocompatible and enhance new bone formation, but the effect of their microstructure on bone regeneration has received little attention. In this study scaffolds of borate bioactive glass (1393B3) with three different microstructures (trabecular, fibrous, and oriented) were compared for their capacity to regenerate bone in a rat calvarial defect model. 12weeks post-implantation the amount of new bone, mineralization, and blood vessel area in the scaffolds were evaluated using histomorphometric analysis and scanning electron microscopy. The amount of new bone formed was 33%, 23%, and 15%, respectively, of the total defect area for the trabecular, oriented, and fibrous microstructures. In comparison, the percent new bone formed in implants composed of silicate 45S5 bioactive glass particles (250-300μm) was 19%. Doping the borate glass with copper (0.4 wt.% CuO) had little effect on bone regeneration in the trabecular and oriented scaffolds, but significantly enhanced bone regeneration in the fibrous scaffolds (from 15 to 33%). The scaffolds were completely converted to hydroxyapatite within the 12week implantation. The amount of hydroxyapatite formed, 22%, 35%, and 48%, respectively, for the trabecular, oriented, and fibrous scaffolds, increased with increasing volume fraction of glass in the as-fabricated scaffold. Blood vessels infiltrated into all the scaffolds, but the trabecular scaffolds had a higher average blood vessel area compared with the oriented and fibrous scaffolds. While all three scaffold microstructures were effective in supporting bone regeneration, the trabecular scaffolds supported more bone formation and may be more promising in bone repair.

  7. Fabrication of luminescent hydroxyapatite nanorods through surface-initiated RAFT polymerization: Characterization, biological imaging and drug delivery applications

    NASA Astrophysics Data System (ADS)

    Heng, Chunning; Zheng, Xiaoyan; Liu, Meiying; Xu, Dazhuang; Huang, Hongye; Deng, Fengjie; Hui, Junfeng; Zhang, Xiaoyong; Wei, Yen

    2016-11-01

    Hydroxyapatite nanomaterials as an important class of nanomaterials, have been widely applied for different biomedical applications for their excellent biocompatibility, biodegradation potential and low cost. In this work, hydroxyapatite nanorods with uniform size and morphology were prepared through hydrothermal synthesis. The surfaces of these hydroxyapatite nanorods are covered with hydrophobic oleic acid, making them poor dispersibility in aqueous solution and difficult for biomedical applications. To overcome this issue, a simple surface initiated polymerization strategy has been developed via combination of the surface ligand exchange and reversible addition fragmentation chain transfer (RAFT) polymerization. Hydroxyapatite nanorods were first modified with Riboflavin-5-phosphate sodium (RPSSD) via ligand exchange reaction between the phosphate group of RPSSD and oleic acid. Then hydroxyl group of nHAp-RPSSD was used to immobilize chain transfer agent, which was used as the initiator for surface-initiated RAFT polymerization. The nHAp-RPSSD-poly(IA-PEGMA) nanocomposites were characterized by means of 1H nuclear magnetic resonance, Fourier transform infrared spectroscopy, fluorescence spectroscopy and thermal gravimetric analysis in detailed. The biocompatibility, biological imaging and drug delivery of nHAp-RPSSD-poly(IA-PEGMA) were also investigated. Results showed that nHAp-RPSSD-poly(IA-PEGMA) exhibited excellent water dispersibility, desirable optical properties, good biocompatibility and high drug loading capability, making them promising candidates for biological imaging and controlled drug delivery applications.

  8. Fabrication of polycaprolactone scaffolds using a sacrificial compression-molding process.

    PubMed

    Yao, Donggang; Smith, Aaron; Nagarajan, Pratapkumar; Vasquez, Adrian; Dang, Loan; Chaudhry, G Rasul

    2006-05-01

    A method of compression-molding fine-powder blends of polycaprolactone (PCL) and poly(ethylene oxide) (PEO) and subsequently dissolving the PEO phase was investigated to prepare porous PCL scaffolds. Different mixing ratios of the two polymers from 20 to 70% PCL were used to study the effect of the mixing ratio on the morphology formation of the scaffold. The mixing ratio was found to play an important role in affecting the porosity of the scaffold and the size of pores. Murine embryonic stem cell derived osteogenic cells were utilized to test the suitability of these scaffolds in tissue engineering applications. The seeded cells were able to colonize and grow in these scaffolds. Based on the overall consideration of morphology, mechanical performance, and ability for cell attachment and proliferation, the scaffolds with approximately 30-40% PCL appear to be an appropriate choice for tissue engineering. These findings suggest that sacrificial compression-molding of PCL-PEO powder blends can be used in the generation of biocompatible scaffolds with controllable porosity and pore size and may be used for in vitro tissue engineering applications.

  9. Fabrication and characterization of curcumin-loaded silk fibroin/P(LLA-CL) nanofibrous scaffold

    NASA Astrophysics Data System (ADS)

    Lian, Yuan; Zhan, Jian-Chao; Zhang, Kui-Hua; Mo, Xiu-Mei

    2014-12-01

    Curcumin exhibited excellent properties including antioxidant, antiinflammatory, antiviral, antibacterial, antifungal, anticancer, and anticoagulant activities. In this study, curcumin was incorporated into silk fibroin (SF)/poly(L-lactic acid- co-e-caprolactone) (P(LLA-CL)) nanofibrous scaffolds via electrospinning, and changes brought about by raising the curcumin content were observed: SEM images showed that the average nanofibrous diameter decreased at the beginning and then increased, and the nanofibers became uniform; FTIR showed that the conformation of SF transforming from random coil form to β-sheet structure had not been induced, while SF conformation converted to β-sheet after being treated with 75% ethanol vapor; XRD results confirmed that the crystal structure of (P(LLA-CL)) had been destroyed; The mechanical test illustrated that nanofibrous scaffolds still maintained good mechanical properties. Further, curcumin-loaded nanofibrous scaffolds were evaluated for drug release, antioxidant and antimicrobial activities in vitro. The results showed that curcumin presented a sustained release behavior from nanofibrous scaffolds and maintained its free radical scavenging ability, and such scaffolds could effectively inhibit S. aureus growth (> 95%). Thus, curcumin-loaded SF/P(LLA-CL) nanofibrous scaffolds might be potential candidates for wound dressing and tissue engineering scaffolds.

  10. Fabrication and Characterization of Biomimetic Collagen-Apatite Scaffolds with Tunable Structures for Bone Tissue Engineering

    PubMed Central

    Xia, Zengmin; Yu, Xiaohua; Jiang, Xi; Brody, Harold D; Rowe, David W; Wei, Mei

    2013-01-01

    The objective of the current study is to prepare a biomimetic collagen-apatite (Col-Ap) scaffold for improved bone repair and regeneration. A novel bottom-up approach has been developed, which combines a biomimetic self-assembly method with a controllable freeze casting technology. In this study, the mineralized collagen fibers were generated using a simple one-step co-precipitation method which involved collagen self-assembly and in situ apatite precipitation in a collagen-containing modified simulated body fluid (m-SBF). The precipitates were subjected to controllable freeze casting, forming scaffolds with either an isotropic equiaxed structure or a unidirectional lamellar structure. These scaffolds were comprised of collagen fibers and poorly crystalline bone-like carbonated apatite nanoparticles. The mineral content in the scaffold could be tailored in a range 0–54 wt% by simply adjusting the collagen content in the m-SBF. Further, the mechanisms of the formation of both the equiaxed and the lamellar scaffolds were investigated, and freezing regimes for equiaxed and lamellar solidification were established. Finally, bone forming capability of such prepared scaffolds was evaluated in vivo in a mouse calvarial defect model. It was confirmed that the scaffolds well support new bone formation. PMID:23567944

  11. Fabrication of three-dimensional porous scaffolds of complicated shape for tissue engineering. I. Compression molding based on flexible-rigid combined mold.

    PubMed

    Wu, Linbo; Zhang, Hong; Zhang, Junchuan; Ding, Jiandong

    2005-01-01

    A novel method for the fabrication of complexly shaped three-dimensional porous scaffolds has been developed by combining modified compression molding and conventional particulate leaching. The resultant scaffolds of various shapes, including some shaped like auricles, were made of hydrophobic biodegradable and bioresorbable poly(D,L-lactic acid) (PDLLA) and poly(D,L-lactic-co-glycolic acid) (PLGA). A polymer-particulate mixture was first prepared by the conventional solvent casting method and then compressively molded in a specially designed flexible-rigid combined mold which facilitates shaping and mold release during the fabrication process. The molding was carried out at a moderate temperature, above the glass transition temperature and below the flow temperature of these amorphous polymers. A porous scaffold was then obtained after particulate leaching. The pores are highly interconnected and uniformly distributed both in the bulk and on the external surface of the scaffolds, and the porosity can exceed 90%. The mechanical properties of the resultant porous scaffolds are satisfactory as determined by measurements of compressive modulus and compressive stress at 10% strain. Good viability of cells seeded in the porous scaffolds was confirmed. This novel fabrication method is promising in tissue engineering because of its ability to produce precise and complexly (anatomically) shaped porous scaffolds.

  12. Fabrication of cell penetration enhanced poly (l-lactic acid-co-ɛ-caprolactone)/silk vascular scaffolds utilizing air-impedance electrospinning.

    PubMed

    Yin, Anlin; Li, Jiukai; Bowlin, Gary L; Li, Dawei; Rodriguez, Isaac A; Wang, Jing; Wu, Tong; Ei-Hamshary, Hany A; Al-Deyab, Salem S; Mo, Xiumei

    2014-08-01

    In the vascular prosthetic field, the prevailing thought is that for clinical, long-term success, especially bioresorbable grafts, cellular migration and penetration into the prosthetic structure is required to promote neointima formation and vascular wall development. In this study, we fabricated poly (l-lactic acid-co-ɛ-caprolactone) P(LLA-CL)/silk fibroin (SF) vascular scaffolds through electrospinning using both perforated mandrel subjected to various intraluminal air pressures (0-300kPa), and solid mandrel. The scaffolds were evaluated the cellular infiltration in vitro and mechanical properties. Vascular scaffolds were seeded with smooth muscle cells (SMCs) to evaluate cellular infiltration at 1, 7, and 14 days. The results revealed that air-impedance scaffolds allowed significantly more cell infiltration as compared to the scaffolds fabricated with solid mandrel. Meanwhile, results showed that both mandrel model and applied air pressure determined the interfiber distance and the alignment of fibers in the enhanced porosity regions of the structure which influenced cell infiltration. Uniaxial tensile testing indicated that the air-impedance scaffolds have sufficient ultimate strength, suture retention strength, and burst pressure as well as compliance approximating a native artery. In conclusion, the air-impedance scaffolds improved cellular infiltration without compromising overall biomechanical properties. These results support the scaffold's potential for vascular grafting and in situ regeneration.

  13. Bio-safe processing of polylactic-co-caprolactone and polylactic acid blends to fabricate fibrous porous scaffolds for in vitro mesenchymal stem cells adhesion and proliferation.

    PubMed

    Salerno, Aurelio; Guarino, Vincenzo; Oliviero, Olimpia; Ambrosio, Luigi; Domingo, Concepción

    2016-06-01

    In this study, the design and fabrication of porous scaffolds, made of blends of polylactic-co-caprolactone (PLC) and polylactic acid (PLA) polymers, for tissue engineering applications is reported. The scaffolds are prepared by means of a bio-safe thermally induced phase separation (TIPS) approach with or without the addition of NaCl particles used as particulate porogen. The scaffolds are characterized to assess their crystalline structure, morphology and mechanical properties, and the texture of the pores and the pore size distribution. Moreover, in vitro human mesenchymal stem cells (hMSCs) culture tests have been carried out to demonstrate the biocompatibility of the scaffolds. The results of this study demonstrate that all of the scaffold materials processed by means of TIPS process are semi-crystalline. Furthermore, the blend composition affected polymer crystallization and, in turn, the nano and macro-structural properties of the scaffolds. Indeed, neat PLC and neat PLA crystallize into globular and randomly arranged sub micro-size scale fibrous conformations, respectively. Concomitantly, the addition of NaCl particles during the fabrication route allows for the creation of an interconnected network of large pores inside the primary structure while resulted in a significant decrease of scaffolds mechanical response. Finally, the results of cell culture tests demonstrate that both the micro and macro-structure of the scaffold affect the in vitro hMSCs adhesion and proliferation.

  14. Micro/Nano Multilayered Scaffolds of PLGA and Collagen by Alternately Electrospinning for Bone Tissue Engineering.

    PubMed

    Kwak, Sanghwa; Haider, Adnan; Gupta, Kailash Chandra; Kim, Sukyoung; Kang, Inn-Kyu

    2016-12-01

    The dual extrusion electrospinning technique was used to fabricate multilayered 3D scaffolds by stacking microfibrous meshes of poly(lactic acid-co-glycolic acid) (PLGA) in alternate fashion to micro/nano mixed fibrous meshes of PLGA and collagen. To fabricate the multilayered scaffold, 35 wt% solution of PLGA in THF-DMF binary solvent (3:1) and 5 wt% solution of collagen in hexafluoroisopropanol (HFIP) with and without hydroxyapatite nanorods (nHA) were used. The dual and individual electrospinning of PLGA and collagen were carried out at flow rates of 1.0 and 0.5 mL/h, respectively, at an applied voltage of 20 kV. The density of collagen fibers in multilayered scaffolds has controlled the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. The homogeneous dispersion of glutamic acid-modified hydroxyapatite nanorods (nHA-GA) in collagen solution has improved the osteogenic properties of fabricated multilayered scaffolds. The fabricated multilayered scaffolds were characterized using FT-IR, X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM). The scanning electron microscopy (FE-SEM) was used to evaluate the adhesion and spreads of MC3T3-E1 cells on multilayered scaffolds. The activity of MC3T3-E1 cells on the multilayered scaffolds was evaluated by applying MTT, alkaline phosphatase, Alizarin Red, von Kossa, and cytoskeleton F-actin assaying protocols. The micro/nano fibrous PLGA-Col-HA scaffolds were found to be highly bioactive in comparison to pristine microfibrous PLGA and micro/nano mixed fibrous PLGA and Col scaffolds.

  15. Micro/Nano Multilayered Scaffolds of PLGA and Collagen by Alternately Electrospinning for Bone Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Kwak, Sanghwa; Haider, Adnan; Gupta, Kailash Chandra; Kim, Sukyoung; Kang, Inn-Kyu

    2016-07-01

    The dual extrusion electrospinning technique was used to fabricate multilayered 3D scaffolds by stacking microfibrous meshes of poly(lactic acid-co-glycolic acid) (PLGA) in alternate fashion to micro/nano mixed fibrous meshes of PLGA and collagen. To fabricate the multilayered scaffold, 35 wt% solution of PLGA in THF-DMF binary solvent (3:1) and 5 wt% solution of collagen in hexafluoroisopropanol (HFIP) with and without hydroxyapatite nanorods (nHA) were used. The dual and individual electrospinning of PLGA and collagen were carried out at flow rates of 1.0 and 0.5 mL/h, respectively, at an applied voltage of 20 kV. The density of collagen fibers in multilayered scaffolds has controlled the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. The homogeneous dispersion of glutamic acid-modified hydroxyapatite nanorods (nHA-GA) in collagen solution has improved the osteogenic properties of fabricated multilayered scaffolds. The fabricated multilayered scaffolds were characterized using FT-IR, X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM). The scanning electron microscopy (FE-SEM) was used to evaluate the adhesion and spreads of MC3T3-E1 cells on multilayered scaffolds. The activity of MC3T3-E1 cells on the multilayered scaffolds was evaluated by applying MTT, alkaline phosphatase, Alizarin Red, von Kossa, and cytoskeleton F-actin assaying protocols. The micro/nano fibrous PLGA-Col-HA scaffolds were found to be highly bioactive in comparison to pristine microfibrous PLGA and micro/nano mixed fibrous PLGA and Col scaffolds.