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A Sr-incorporated Na–Ti–O nano-network with a lateral pore size of 20–300 nm was developed on titanium (Ti) substrate using one-step alkali etching in a mixed solution of NaOH and Sr(OH)₂. The pore size of coating increases with Sr content, implying the proper amount of Sr in the electrolyte accelerates nanowire aggregation. The Sr(OH)₂ particle precipitation has no significant effect on the coating morphology. Moreover, biological experiments suggest the prepared coating exhibits good cytocompatibility, and the amount of Sr under 0.7 at.% has no noticeable promoting effect on the cytocompatibility.

In order to improve the mechanical compatibility and cytocompatibility of titanium implants, tantalum coatings were prepared using plasma spraying technology. Tantalum coatings have been deposited via atmospheric plasama spraying (APS) and vacuum plasma spraying (VPS) methods, and then their morphologies, porosities, bonding strengths and elastic modulous were investigated. In vitro cytocompatibility of the two coatings was evaluated via human bone marrow stromal cells (hBMSCs). The results show that oxidation phenomenon was observed for the APS tantalum coatings, while less oxidation was found in the VPS tantalum coatings. Compared with APS tantalum coatings, the VPS tantalum coatings have a more compact microstructure and less impurity content, resulting in a better bonding with the titanium substrate. VPS tantalum coatings were measured to have a lower elastic modulus and a higher hardness than APS Tantalum coatings. Electrochemical corrosion of the coatings were examined and the VPS tantalum coating showed improved chemical stability. Besides, bone marrow stem cells (BMSCs) adhere to and spread well on the surface of both VPS and APS tantalum coatings without significant difference. The proliferation rate of BMSCs is higher on VPS tantalum coating surface than on APS tantalum coatings. Our results suggest that VPS tantalum coatings are more suitable for the application of surface modification of titanium implant due to their lower elastic modulus and better chemical stability for higher mechanical compatibility and cytocompatibility.

Influence of carboxylic functionalization on the cytocompatibility of multiwalled carbon nanotubes (MWCNTs) was investigated in this work. Water contact angle assay showed that the surface of MWCNTs-containing carboxyl (MWCNTs-COOH) became much more hydrophilic compared with pure MWCNTs. In cell-adhesion assays, two cell lines, mouse fibroblast cells (L929) and human umbilical vein endothelial cells (EAHY926) were used to assess the cytocompatibility of materials. The MWCNTs-COOH displayed the improved cell proliferation, viability and adhesion due to the enhanced wettability, indicating their superior cytocompatibility over MWCNTs. The existence of carboxyl groups should be benefit to the adhesion and growth of both cells, which implied that MWCNTs-COOH were helpful for seeding both cells and could be used as the functional surface for the adhesion and growth of cells.

In this paper, silicates/poly (l-lactic acid)-co-bisphenol A epoxy resin assemblies with high modulus were developed by in situ polymerization of l-lactic acid and surface-modified lamellar vermiculites for potential applications in tissue engineering. These assemblies represented advances in the mechanical properties that can be hardly obtained in other assemblies formed via physical interactions. The covalent grafting of the PLLA based polymers onto the vermiculites surface was confirmed by X-ray photon spectroscopy. The elastic moduli of the assemblies measured by an atomic force microscope were around 7 GPa, and higher than the elastic moduli of the pure polymer (3.2 GPa) and unmodified vermiculites (1.5 GPa), respectively. Images demonstrated that cells proliferated and reached confluence on both the assemblies and pure polymer materials, which indicated that the assemblies exhibited the similar cytocompatibility with pure polymer. With the addition of 5 wt.% assemblies, the polymer and assemblies blended-composites exhibited a 118% improvement in compressive strength and 117% improvement in modulus compared with pure polymer. The present work demonstrated a strategy for the assembly of biomacromolecules and inorganic layers and fabrication of biomaterials high in modulus for tissue engineering applications.

Gelatin-based drug carrier matrices have emerged as very promising class of delivery system. The purpose of this investigation was to develop drug loaded gelatin-based gels (composites). Gelatin matrices were crosslinked with genipin, a naturally occurring crosslinker for the release of indomethacin. Indomethacin, a low molecular weight and moderately hydrophobic, anti-inflammatory agent was incorporated into the gelatin matrices to form drug loaded gel composites for the release study. The gels were subjected to temperature-dependent oscillatory rheology. The result showed pouring temperature in the range of ~31–34°C for the un-crosslinked gels while the crosslinked gels did not show crossover point. Gels were studied for surface morphology using scanning electron microscopy and a porous network structure was observed. The release of indomethacin from the gels indicated an initial increase in the release rate with the increase in drug concentrations. It was observed that drug composites with higher drug concentration exhibited higher drug transport. Swelling and crosslinking played a crucial role in regulating the drug transport. Further, viability assay suggested biocompatibility of these matrices in vitro. Gel in vitro cell compatibility using live dead assay evaluated with AH-927 cell line indicated normal cell proliferation without any harmful effect and thus suggesting appropriateness of crosslinked composites as potential drug carrier.

Titanium (Ti) is widely used for making tissue engineering implants, due to its good corrosion resistance, biocompatibility and mechanical properties. However, bare Ti does not integrate well with natural bone tissue and releases ions and particles that are harmful to the extracellular matrix. To overcome these problems, the Ti substrate could be coated with various biocompatible materials including a composite of gelatin and hydroxyapatite (HA). However, few have characterized and evaluated the coating of gelatin/HA on Ti substrate and its effect on bone related cells. In this study, samples of Ti substrate coated with gelatin/HA composite were fabricated with gelatin concentration ranging from 0 to 200 mg/L. The porous surface structure of gelatin/HA composite formed on the Ti substrate was then examined and characterized for its composition and topography by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and image processing and analysis software (ImageJ), respectively. Subsequently, rat bone marrow-derived mesenchymal stromal cells (BMMSC) were cultured on the surface of gelatin/HA composite on Ti substrate, and evaluated for cell morphology, proliferation, and osteo-differentiation using SEM, MTT assay, and alkaline phosphatase (ALP) assay, respectively. It is shown that gelatin enhanced binding of HA onto Ti substrate, and the topography of the porous surface structures was influenced by gelatin concentration only for the large pore sizes. Furthermore, the results indicate that the porous surface structures of gelatin/HA on Ti substrate promoted proliferation and osteo–differentiation as compared to the naked pure Ti substrate, particularly on that with concentration of gelatin at 100 mg/L. These findings, taken together, suggest that Ti substrate can be coated with different porous surface structures of gelatin/HA composite with gelatin solution of different concentrations. Such coated Ti substrates can promote cytocompitibility and osteo-differentiation of BMMSC, and thus may be of potential in development of implants and devices for bone tissue engineering.