Silver doped diamond-like carbon antibacterial and corrosion resistance coatings on titanium

Abstract

The present work is focused on the micro-structural, antibacterial potential and corrosion resistance of silver (Ag) doped diamond-like carbon (DLC) coatings deposited by Thermionic Vacuum Arc on titanium substrates. The Ag-DLC coatings have spherical nanoparticulates in the film, with a size of either ≈50 nm or ≈20 nm, depending on the deposition time. The incorporation of Ag in the DLC coatings was clearly evident, as observed in both energy dispersive X-ray spectroscopy and in structural analysis (X-ray diffraction), while X-ray photoelectron spectroscopy confirmed their composition as well as the presence of Ag and diamond-like carbon. Such coatings show an increase in the wettability, which can be related to the increase in the surface free energy. Comparing their corrosion resistance to bare (uncoated) titanium, an increased electrochemical stability is observed. Subsequently, the silver release profiles in phosphate buffer saline, for a 10 days period, were investigated; the release is initially fast in the first 12 h followed by saturation at 66 h. These coatings were further investigated for antibacterial efficacy against Staphylococcus aureus (model Gram positive bacteria) which confirms that the silver doped DLC coatings exhibit an excellent antibacterial activity.