A gelatin-based fibrous hydrogel with extreme temperature tolerance and multimodal biofunctionality for skin...

Hydrogels hold great promise for tissue regeneration, antibacterial therapy, and antitumor applications, yet their practical utility in harsh conditions is often constrained by poor environmental stability, including freezing at subzero temperatures and dehydration at elevated temperatures. To overcome these challenges, we engineer a natural material-based fibrous hydrogel (4A-FH) through a water-glycerol solvent system that ensures "4A" extreme temperature tolerance (anti-drying, anti-freezing, anti-swelling, and anti-pressure), thereby conferring long-term moisture retention, structural integrity, and mechanical flexibility after prolonged storage at extreme temperatures (-20 °C to 42 °C). 4A-FH is fabricated by crosslinking gelatin with tea trichome, a phenolic-rich fibrous material isolated from tea, which not only reinforces its mechanical strength (exhibiting rapid recovery after 80 % compression) but also imparts multifunctional properties, including antioxidant activity, tissue adhesiveness, self-healing capability, and photothermal responsiveness. Furthermore, 4A-FH possesses excellent clinical applicability, including injectability and biocompatibility. Notably, the hydrogel effectively mitigates cold-induced skin damage (e.g., frostbite) and, when combined with photothermal stimulation, significantly enhances full-thickness wound repair by modulating macrophage polarization, accelerating re-epithelialization, and promoting angiogenesis. In summary, 4A-FH synergistically integrates the "4A" environmental resilience, intrinsic therapeutic functions (antioxidant and photothermal), and favorable biomedical applicability (injectability, self-healing, tissue adhesion, and biocompatibility), presenting a versatile hydrogel dressing for advanced wound care and skin protection.