1.D.317.  The Porous TiO₂/Silver Antibacterial Layer (PTSA-L) Family

Necula et al. 2009 synthesized a porous TiO₂-Ag composite coating and assessed its in vitro bactericidal activity against methicillin-resistant Staphylococcus aureus. The coating was produced by plasma electrolytic oxidation of Ti-6Al-7Nb medical alloy in a calcium acetate/calcium glycerophosphate electrolyte bearing Ag nanoparticles. Following oxidation, the surface of the titanium substrate was converted into the corresponding oxide (TiO₂) bearing Ca and P species from the electrolyte. In addition, Ag was detected associated with particles present in the oxide layers. The coatings revealed a porous interconnected structure with pores up to 3 microm in size, a threefold increase in roughness and improved wettability relative to the non-oxidized specimens. The composite TiO₂-Ag coating showed complete killing of methicillin-resistant S. aureus within 24h in all culture conditions, whereas a 1000-fold increase in bacterial numbers was recorded with the ground titanium specimens and the samples oxidized in the absence of Ag nanoparticles (Necula et al. 2009).