Antibacterial titanium dioxide coatings for CoCrMo orthopaedic implants

Periprosthetic joint infections (PJIs) still remain a severe complication after arthroplasty despite the significant advances in manufacturing materials in the orthopaedic field. The sol-gel based coating strategy is attracting interest for its multifaceted potential to design surfaces capable of exerting antibacterial properties. In this study, the sol-gel technique is employed to obtain a new class of titanium dioxide coatings doped with silver and gallium ions to minimize the adhesion and bacterial colonization on the CoCrMo surfaces. Uniform anatase titania coatings with hydrophobic behaviour and nanometer thickness (50-200 nm) were obtained by dipping CoCrMo samples in TiO2 sols with different compositions. The physicochemical characterization of coatings using EDS, GDOES, and ICP-OES confirmed the incorporation of doping agents. Antimicrobial assays were performed against Gram-positive S. aureus and Gram-negative E. coli bacteria, demonstrating a satisfying anti-bacterial activity. Furthermore, all the coatings tested showed no cytotoxicity and osteodifferentiation potential. Thus, the herein sol-gel strategy could represent a powerful tool for surface modification of CoCrMo-based materials for implantable devices.