H/J-Aggregates Astaxanthin Nanoparticles Alleviate UV-Induced Skin Photoaging

Chronic exposure to ultraviolet A (UVA) and ultraviolet B (UVB) radiation accelerates skin photoaging through oxidative stress and inflammation, emphasizing the importance of antioxidant protection. Astaxanthin (AST), a natural antioxidant, self-assembles into H- and J-aggregates with unique molecular arrangements and optical properties, providing distinct molecular architectures for functional nanomaterial design. However, its high sensitivity to preparation conditions makes the separate preparation and stabilization of H- and J-aggregates astaxanthin difficult. Here, H- and J-aggregates astaxanthin were separately stabilized in bovine serum albumin/chitosan nanoparticles (H-ABC-NPs and J-ABC-NPs) to evaluate their protective effects against UV-induced skin photoaging. H/J-ABC-NPs showed antioxidant activity and protected L929 fibroblasts against H2O2-induced oxidative stress by reducing intracellular ROS and MDA levels and increasing SOD and CAT activities. In a UVB/UVA-induced BALB/c mouse model of skin photoaging, topical H/J-ABC-NPs alleviated wrinkle formation, epidermal thickening and collagen fiber disruption. These effects were accompanied by enhanced SOD, CAT and GSH-Px and reduced MDA and inflammatory responses in the skin and serum. H/J-ABC-NPs reduced MMP-1 levels and collagen loss while increasing HYP and HA levels. Overall, these results indicate that H/J-ABC-NPs effectively alleviate UVB/UVA-induced skin photoaging, accompanied by reduced oxidative stress, reduced inflammation and the preservation of skin structure. The separate stabilization and biological evaluation of H- and J-aggregates astaxanthin provide a basis for further investigating their biological effects and topical applications.