Surface Functionalization of TiO₂ With an Albumin-Teicoplanin Complex to Prevent Implant-Associated Infections.

Abstract

Postoperative infection and aseptic loosening are leading causes of orthopedic implant failure, often necessitating complex and costly revision surgeries. Teicoplanin (TP), a glycopeptide antibiotic effective against methicillin-resistant Staphylococcus aureus (MRSA), and albumin (AB), a biocompatible carrier protein, present a promising strategy for implant surface functionalization. However, previous approaches using intermediate adhesive layers have demonstrated limited antibiotic retention following physiological conditioning. This study investigates the direct functionalization of titanium dioxide (TiO₂) powder with an AB-TP complex to develop a stable antibacterial surface coating capable of retaining efficacy after phosphate exposure. The AB-TP complex was prepared and immobilized onto TiO₂ powder. AB attachment kinetics and stability were assessed using the bicinchoninic acid (BCA) assay after short-term incubation, serial buffer washes, and extended conditioning. In vitro, antibacterial efficacy was evaluated against S. aureus using viable count assays and disk diffusion. Additional tests assessed TP leaching following sample conditioning. The biological response of osteoblast-like MG63 cells to AB-TP was examined to evaluate cytocompatibility and pro-osteogenic potential. AB demonstrated rapid and irreversible binding to TiO₂, with negligible protein loss following 10 washes or 7-day physiological buffer incubation. AB-TP-TiO₂ completely inhibited bacterial growth (6.18-log reduction). Following phosphate conditioning, AB-TP-TiO₂ retained antibacterial activity, with log reductions of 3.3. Disk diffusion confirmed no TP leaching from AB-TP-TiO₂, in contrast to TP-TiO₂, which exhibited significant antibiotic release and complete loss of antibacterial function post-conditioning. Treatment of MG63 with the AB-TP supported significant cell growth and increased alkaline phosphatase activity. Direct functionalization of TiO₂ with the AB-TP complex yields a stable, durable, and antibacterial surface capable of withstanding physiological conditions. This approach bypasses the limitations of adhesive layers and demonstrates potential for application in orthopedic implant coatings.