Hydrogel-Based Systems for Controlled Delivery of Photosensitizers in Photodynamic Therapy: A Systematic Review

This systematic review aims to evaluate the design, performance, and biomedical applications of hydrogel-based systems for the controlled delivery of photosensitizers used in photodynamic therapy (PDT). Hydrogels have emerged as versatile biomaterials capable of improving photosensitizer stability, localization, and controlled release, potentially enhancing therapeutic efficacy and reducing off-target phototoxicity. The review will synthesize evidence from preclinical and clinical studies investigating hydrogel–photosensitizer systems applied in photodynamic therapy, with particular emphasis on cancer treatment. Outcomes related to delivery efficiency, therapeutic effectiveness, selectivity, safety, and release kinetics will be critically assessed.