Photodynamic Strategies for Prevention of Titanium Osteoimplant Infections

The growing demand for orthopedic implants, driven by an aging global population and the rising occurrence of bone abnormalities and defects, relies heavily on biocompatible titanium (Ti) and its alloys. However, their inherent biological inertness often results in poor osseointegration and increased vulnerability to bacterial infections, particularly those caused by biofilm-forming pathogens. Traditional antibiotic treatments frequently fail against biofilms and contribute to the escalating problem of antibiotic resistance, emphasizing the need for alternative therapies that do not foster resistance. Photodynamic therapy (PDT), which uses light-activated photosensitizers to generate reactive oxygen species (ROS) for effective bacterial eradication, presents a promising noninvasive strategy with high precision and low likelihood of resistance development. This review thoroughly explores the mechanisms of PDT and its application to Ti implants, focusing on both organic and inorganic photosensitizers. Moreover, considering current challenges, the study investigates approaches to improve PDT's effectiveness in combating implant-related infections. These include optimizing PDT systems, developing new AIE-active photosensitizers, increasing oxygen supply to boost ROS production, combining multi-modal antibacterial treatments, and designing dual-functional implants. The review aims to identify current limitations and propose future directions, offering valuable insights to advance PDT-based strategies that enhance the antibacterial performance of Ti implants in the post-antibiotic era.