Silver-containing hydroxyapatite (HA) coatings have been prepared on titanium substrate by vacuum plasma spraying (VPS) method and anti-bacterial properties of the coatings were examined. Three types of bacteria stains, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, were employed in this test. The results showed that the silver-containing HA coatings exhibited significant anti-bacterial effects against the three bacteria with anti-bacterial ratios higher than 95%. The release of silver ions in the physiological environment ensured excellent anti-bacterial properties of the silver-containing HA coatings. International standard ISO 10993-12 was adopted for cytotoxicity evaluation using fibroblast cell line L929, and it was found that the cytotoxicity for the coatings ranked 0 that showed no cytotoxicity for the coatings. Hemolysis test was processed according to ASTM F 756 standard with anti-coagulated rabbit blood, and the hemolysis ratios of the coatings were below 0.4%, indicating of non-hemolysis for the coatings.

Tantalum, as a potential metallic implant biomaterial, is attracting more and more attention because of its excellent anticorrosion and biocompatibility. However, its significantly high elastic modulus and large mechanical incompatibility with bone tissue make it unsuitable for load-bearing implants. In this study, porous tantalum coatings were first successfully fabricated on titanium substrates by vacuum plasma spraying (VPS), which would exert the excellent biocompatibility of tantalum and alleviate the elastic modulus of tantalum for bone tissue. We evaluated cytocompatibility and osteogenesis activity of the porous tantalum coatings using human bone marrow stromal cells (hBMSCs) and its ability to repair rabbit femur bone defects. The morphology and actin cytoskeletons of hBMSCs were observed via electron microscopy and confocal, and the cell viability, proliferation and osteogenic differentiation potential of hBMSCs were examined quantitatively by PrestoBlue assay, Ki67 immunofluorescence assay, real-time PCR technology and ALP staining. For in vivo detection, the repaired femur were evaluated by histomorphology and double fluorescence labeling 3 months postoperation. Porous tantalum coating surfaces promoted hBMSCs adhesion, proliferation, osteogenesis activity and had better osseointegration and faster new bone formation rate than titanium coating control. Our observation suggested that the porous tantalum coatings had good biocompatibility and could enhance osseoinductivity in vitro and promote new bone formation in vivo. The porous tantalum coatings prepared by VPS is a promising strategy for bone regeneration.

No abstract