Achieving bacteria eradication on titanium implants: synergistic effect of tannic acid coating and levofloxacin

Titanium (Ti)-based implants may cause implant-related infections (IRIs) due to contamination before or during surgery. Tannic acid (TA) coatings offer a promising strategy to prevent IRIs owing to their antibacterial properties. TA binds strongly to metal oxide surfaces, forming stable self-assembled layers. We developed a simple method based on TA adsorption onto rough Ti substrates combined with a low dose of levofloxacin (LEV) to eradicate Staphylococcus aureus biofilms, the species most frequently associated with orthopedic implants. Physicochemical analyses (ATR-FTIR, contact angle, electrochemistry, AFM) confirmed TA deposition, increased hydrophilicity, and altered surface morphology. Microbiological assays revealed a two-log reduction in viable bacteria on TA-coated surfaces and a three-log reduction on LEV-treated surfaces compared to untreated Ti. Notably, the combined TA functionalization + LEV treatment exhibited a synergistic effect, resulting in effective bacterial eradication. These results highlight the potential of this approach as a preventive strategy for IRIs on Ti implants.