Antibacterial Property and Biocompatibility of Plasma Sprayed Hydroxyapatite / Silver Composite Coatings

Hydroxyapatite / silver (HA/Ag) composite coatings have been fabricated on titanium substrate by vacuum plasma spraying and their antibacterial properties were examined. Three types of bacteria stains, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, were employed in this study. The results obtained showed that the silver-containing HA coatings exhibited significant antibacterial effects against the three kinds of bacteria with antibacterial ratios higher than 95%. The release of silver ions in the physiological environment ensured excellent antibacterial properties for the silver-containing HA coatings. Cytotoxicity evaluation, haemolysis test and simulated body fluid (SBF) immersion were carried out to examine biocompatibility and bioactivity for the coatings. It was found that the cytotoxicity for the coatings ranked 0 that showed no cytotoxicity for the coatings, and the hemolysis ratios of the coatings were below 0.4%, indicating of nonhemolysis for the coatings. In SBF test, the HA/Ag composite coatings were covered by bone-like apatite layer after immersed in SBF, suggesting that their bioactivity was not affected obviously by the addition of silver in the coatings.