Advances in Polydopamine-Based Nanoplatforms: Antioxidant Mechanisms and Applications in Oxidative Stress-Mediated Diseases

Polydopamine (PDA) exhibits unique advantages in the treatment of oxidative damage owing to its melanin-mimetic structure, abundant redox-active functional groups, and excellent biocompatibility. Distinct from conventional antioxidant molecules, PDA-based nanoplatforms can efficiently eliminate reactive oxygen species (ROS) via hydrogen atom transfer and electron transfer mechanisms, while relying on the dynamic redox cycling of catechol/quinone moieties to achieve sustained antioxidant activity. However, systematic summaries of PDA-based antioxidant nanoplatforms remain relatively limited. Therefore, this review provides a comprehensive overview of the antioxidant mechanisms of PDA and its associated physicochemical properties, with particular emphasis on the design strategies of diverse PDA-based nanoplatforms, including solid, mesoporous, hollow, doped, and coated architectures, as well as the effects of structural features, particle size, composition, and surface charge on their antioxidant performance. In addition, recent research progress is systematically categorized around core pathological challenges, including breaking ROS-inflammation feedback loops, overcoming biological delivery barriers, remodeling regenerative microenvironments, and regulating programmed cell death.