Chitosan-based nanozyme hydrogels: Advanced antioxidant and sustained-release systems for the prevention and treatment of skin photoaging

Photoaging of the skin is a chronic damage process caused by prolonged exposure to ultraviolet radiation, characterized by increased oxidative stress, activation of inflammatory responses, and collagen degradation. However, photoaging of the skin presents challenges in prevention, limited efficacy of therapeutic agents, and difficulties in repairing the damage. In recent years, chitosan-based hydrogels, which exhibit excellent biocompatibility, biodegradability, film-forming properties, and the ability to deliver sustained-release medication, have progressively emerged as cutting-edge therapeutic agents for treating photoaging of the skin. Nanozymes are nanomaterials possessing enzymatic functions that effectively scavenge reactive oxygen species generated by ultraviolet irradiation, exhibiting excellent antioxidant properties. Loading nanozymes into chitosan-based hydrogels not only combines the biocompatibility of chitosan hydrogels with the antioxidant properties of nanozymes to enhance therapeutic efficacy but also enables stable loading and controlled release of drugs and active ingredients. This further improves treatment efficiency while fully leveraging the moisturizing and restorative properties of the hydrogel matrix. This paper systematically summarizes the construction methods, performance optimization, and mechanism of action of chitosan-based nanozyme hydrogels in preventing and treating skin photoaging. It focuses on analyzing research advances in their capacity to scavenge free radicals, alleviate inflammation, and promote skin barrier repair, while exploring their application prospects and challenges in skin repair and the cosmetics sector.