Surface characterisation and silver release from Ti-6Al-4V and anodic TiO2 after surface modification by ion implantation

Abstract

Surface modification of the implant surface via silver ion (Ag+) implantation shows promise in reducing the post-surgery infection rates. Silver was ion implanted into polished Ti-6Al-4V and the anodically oxidised Ti-6Al-4V surfaces at two implantation fluences, namely, 0.4 and 1.2 × 1017 ions/cm2. Anodic oxidation was carried out using the 0.5 M H2SO4 and 2.1 M H3PO4 electrolytes. This study aims to characterise the surfaces and to determine whether surface modification of Ti-6Al-4V via anodic oxidation improves the Ag+ release from the surfaces in vivo. The tested dosages had no appreciable effect on the final amount of stored silver for both studied TiO2 layers as supersaturation of the surface with silver occurs at low dosage. Ag+ release from the anodic TiO2 layers was independent of the electrolyte used to create the anodic layer. Polished Ti-6Al-4V surfaces showed a greater potential silver storage capacity relative to the anodic TiO2 samples since the concentration of silver stored at the surface was roughly proportional to the Ag+ dosage. Comparison of Ag+ release rates of all studied samples with literature to determine the potential antimicrobial effects showed that all studied conditions had the potential to be 100% antimicrobial.