Resistance mechanisms of bacterial biofilms on orthopedic implants and research progress on novel anti-biofilm coatings

Implant-associated infections (IAIs) have become a major challenge in clinical orthopedics due to the formation of bacterial biofilms and their complex resistance mechanisms. This review systematically summarizes the resistance mechanisms of bacterial biofilms on the surface of orthopedic implants and critically analyzes the research progress of novel anti-biofilm coatings. Novel antibiofilm coating strategies have shown a diversified development, which are mainly classified into: antimicrobial drug-releasing strategies, surface physicochemical modification strategies, nanotechnology-based antimicrobial strategies, and emerging bioactive strategies. Studies have shown that it is difficult to balance long-lasting antimicrobial activity and biocompatibility with a single strategy, and there is a need to develop multi-mechanism synergistic coatings (e.g., anti-adhesion, contact-killing, immune-modulatory) and to optimize the coating design by combining with artificial intelligence. Despite the potential of nanotechnology and bioactive strategies, their biosafety assessment, scale-up and long-term in vivo efficacy still need to be thoroughly investigated. This review provides an interdisciplinary perspective and theoretical basis for revealing the nature of biofilm resistance and developing efficient strategies for the prevention and treatment of IAIs.