Antibacterial effects of Ag-HAp thin films on alumina substrates

Ion beam assisted deposition (IBAD) has been successfully used to produce a dense ultra-adherent and pinhole-free hydroxyapatite (HAp) layer on alumin a substrates. After deposition the HAp-coated alumina was immersed in 20 pp m and 100 ppm AgNO3 solution to carry out the ion exchange between Ag- and Ca2+ in HAp. An obvious antimicrobial effect against Escherichia coli, Pseu domonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis wa s observed in the samples treated with 20 ppm AgNO3 solution. In contrast t o this, the untreated samples did not show any bactericidal effect. Scannin g electron microscopy (SEM) studies showed that Ag-rich phases wen homogene ously distributed on the surface. X-ray diffraction (XRD) demonstrated that the surface structure in the samples without Ag was HAp, whereas with Ag i t is HAp and AgCaP. The minimum inhibitory concentration of AgNO3 was measu red to be 1.302 mu g/ml. The release of Ag- ions from the Ag-HAp films in s imulated body fluid (SBF) solution was determined by atomic absorption spec troscopy. (C) 1998 Elsevier Science S.A. All rights reserved.