Optimisation of micro-arc oxidation electrolyte for fabrication of antibacterial coating on titanium

This study has been carried out to optimise the silver (Ag) content of the coating synthesised on commercially pure titanium (Cp–Ti, Grade 4) for biomedical applications by micro-arc oxidation (MAO) process. The MAO process has been conducted in electrolytes containing silver acetate (AgC2H3O2) at different concentrations between 0 and 0·002 mol L−1. When compared to the base electrolyte, coatings synthesised in ≥0·001 mol L−1 AgC2H3O2 added electrolytes exhibited an antibacterial efficiency of 99·98% against Staphylococcus aureus (S. aureus). Detailed examination revealed that the presence of 0·001 mol L−1 AgC2H3O2 in the electrolyte resulted in incorporation of 1·14 wt-% Ag into fabricated coating consisting mainly of outer hydroxyapatite (HA) and inner titanium oxide (TiO2) layers. In comparison to the Ag-free coating, 1·14 wt-% Ag in the coating lowered the proliferation of SAOS-2 cells, which still tended to grow at a relatively low rate with increasing culturing time.