Poly-γ-glutamic Acid/Melanin-like Hydrogel as Efficient UVA Protection and Antioxidative Enhancers for Preventing and Treating UVA-Induced Skin Damage

Excessive ultraviolet (UV) radiation can cause human skin erythema, tanning, inflammation and other adverse reactions. Human skin can spontaneously synthesize endogenous melanin under UV radiation to defend the damage of UV, but the skin problems such as light damage and light aging cannot be avoided due to its low UV shielding efficiency. Therefore, we design a natural and biocompatible PGDA (PDA-L doped sunscreen hydrogel) sunscreen hydrogel by crosslinking melanin-like L-lysine doped polydopamine (PDA-L) and amino acid biopolymer poly-γ-glutamic acid, which displays good biosafety, efficient UVA shielding performance and excellent anti-inflammatory performance in the application of the skin protection of sun and repair after sunburn. The introduction of PDA-L to the hydrogel can improve the absorption intensity in the UV region and antioxidative performance of the hydrogel. Meanwhile, the usage of biocompatible PGDA sunscreen hydrogel can avoid the skin oxidative damage and penetrative toxicity of the conventional sunscreen.