Tannic acid–cerium nanoparticles with enhanced antioxidant activity for UVB-induced skin photodamage repair

Prolonged exposure to ultraviolet (UV) radiation induces oxidative stress, leading to cellular dysfunction and tissue damage. However, currently available natural antioxidants and nanomaterials often suffer from limited stability and low bioavailability, severely restricting their long-term therapeutic efficacy. Here, an antioxidant nanomaterial, tannic acid–cerium nanoparticles (TA–Ce NPs), was constructed via pH-regulated precipitation coupled with the in situ assembly of plant-derived tannic acid and tetravalent cerium ions. The TA–Ce NPs form a metal–polyphenol network architecture and exhibit high biocompatibility and robust structural stability across a wide range of pH and temperature conditions. Notably, TA–Ce NPs efficiently scavenge superoxide anions, hydroxyl radicals, and hydrogen peroxide, thereby overcoming the poor photostability of tannic acid and the limited biocompatibility of cerium oxide when used individually. TA–Ce NPs significantly promote the proliferation and migration of L929 fibroblasts while markedly reducing intracellular reactive oxygen species (ROS) levels, enhancing superoxide dismutase (SOD) activity, and inhibiting lipid peroxidation. Furthermore, a sodium hyaluronate (HA) gel incorporating TA–Ce NPs (TA–Ce NPs/HA) achieves a skin wound-healing rate of 72.83% within 7 d and demonstrates favorable in vivo biosafety in a mouse model of ultraviolet B (UVB)-induced skin photodamage. This work presents a synergistic antioxidant nanoplatform integrating rare earth elements and natural polyphenols, offering considerable potential for skin photodamage repair.