Bacteriophage-Grafted Implant Polymer Coating Prevents Biofilm Formation While Allowing Bone Cell Growth In Vitro

Orthopedic implants often fail due to bacterial infections and biofilm formation caused by drug-resistant strains, particularly Staphylococcus aureus. Bacteriophages (phages) represent a promising strategy for controlling implant-associated infections. In this study, phages targeting S. aureus were purified from wastewater and chemically grafted onto a chitosan coating applied to a Ti-6Al-4V alloy. The phage-grafted coating was abraded against the spongy portion of a porcine femur bone, disinfected using ethanol and UV exposure, and evaluated in vitro for biofilm prevention and osteoblast mineralization. Following abrasion, part of the coating remained intact on the metal surface, and the grafted phages retained their lytic activity after disinfection. Abraded samples containing phages reduced bacterial growth by 90.5% compared with samples without phages (p < 0.01) and effectively prevented biofilm formation 16 h after bacterial inoculation. The 7F2 osteoblasts exhibited significantly higher proliferation on phage-grafted coatings (p < 0.05). Cells cultured on abraded samples showed increased maturation, indicated by alkaline phosphatase activity, and enhanced mineralization, measured by calcium deposition, relative to nonabraded samples (p < 0.01), likely due to increased surface roughness. However, the presence of phages on the coating was associated with reduced calcium deposition (p < 0.01). These results demonstrate that phage-grafted coatings can reduce bacterial growth and prevent biofilm formation without deactivation by biological residues, while maintaining compatibility with bone-forming cells in vitro. This approach may offer a feasible strategy for reducing implant-related infections while allowing bone cell growth.