Self-healing and UV-shielding hydrogels for advanced wound dressings: A nanoparticle-embedded dynamic dual-network of aldehyde sodium alginate and carboxymethyl chitosan

Stable physical integration of TiO 2 NPs into the hydrogel network. • Dynamic mechanical properties and pronounced self‑healing capability. • Excellent biocompatibility, UV‑shielding, and anti‑melanogenic activity. • 98.5% wound closure in a full‑thickness mouse model within 14 days. Excessive UV exposure impedes wound healing by damaging fibroblasts and epithelial cells and stimulates melanocytes to overproduce melanin, leading to post-healing hyperpigmentation. To address this challenge, a dynamic dual-network composite hydrogel was developed via Schiff-base crosslinking between aldehyde sodium alginate (ASA) and carboxymethyl chitosan (CMCS), with titanium dioxide nanoparticles (TiO 2 NPs) incorporated through electrostatic interactions. Based on the dynamic Schiff base chemistry, HAC-TiO 2 - Y hydrogels have good self-healing properties. The incorporation of TiO 2 nanoparticles increases network rigidity and physical crosslinking density. The resulting HAC-TiO 2 - Y hydrogels exhibited excellent biocompatibility, supporting > 85% viability of L929 fibroblasts. It also displayed outstanding UV-blocking capability. Notably, the HAC-TiO 2 -2.5 hydrogel showed concentration-dependent anti-melanogenic activity in B16F10 melanoma cells, reducing intracellular melanin content to 74.2% compared to the control. In a full-thickness mouse wound model, the HAC-TiO 2 -2.5 hydrogel achieved 98.5% wound closure within 14 days, significantly outperforming the TiO 2 -free control. By integrating UV protection with wound healing promotion, this multifunctional hydrogel presents a promising strategy for advanced wound management under UV-exposed conditions. Download: Download high-res image (223KB) Download: Download full-size image