Poly (hexamethylene biguanide) adsorption on hydrogen peroxide treated Ti-Al-V alloys and effects on wettability, antimicrobial efficacy, and cytotoxicity.

An effective amount of the antiseptic agent PHMB cannot simply be placed on the surface of titanium alloys where hydrocarbons were removed by different purification procedures. Pre-treatment of Ti6Al4V specimen with 5% H2O2 in 24 h results in extra introduced -OH and -COOH groups as well as an adsorbed water film on the surface, which provide the base for the subsequent formation of a relatively stable and multi-layered PHMB film. The superficially adhering PHMB film produces no adverse effects on MG63 cells within a 48 h-cell culture, but promotes the initial attachment and spreading of the osteoblasts on the modified Ti6Al4V surface within 15 min. After direct bacterial inoculation of the active sample, the PHMB film reacts antimicrobially against Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis) and Gram-negative strains (Pseudomonas aeruginosa, Escherichia coli) after surface contact. The bactericidal efficacy is only slightly reduced after using of the same specimen for re-testing the antibacterial activity. MG63 cells adhere and proliferate within 48 h on a PHMB film-containing Ti6Al4V surface, which has been pre-contaminated with S. aureus. Bacterial biofilms were only revealed in controls without PHMB.