Non-covalent framework imparting "hot spring" dressing materials with high energy storage density and long-time heat release for wound treatment.

Abstract

Photon energy and low-grade heat are bio-friendly natural energies for creating mild heat stimulation that can promote the tissue repair process by enhancing angiogenesis and accelerating regeneration. Here, a type of azobenzene-containing surfactants is used for electrostatically binding with alginate to fabricate dressing materials with "hot spring" effect. Such dressing materials could address gravimetric energy density as high as 380.6 J/g by harvesting both photon energy and low-grade heat upon UV-charging at room temperature. The stored energies could be released out as upgraded heat for increasing environmental temperature in a controllable way through Vis-discharging. Furthermore, such dressing materials can generate long-term heat release through in situ photothermal conversion from Vis light. In vitro experiments demonstrate that the Vis light-induced mild heat stimulation can effectively enhance cell migration, and in vivo wound healing studies confirm its ability to accelerate tissue regeneration. This study opens an opportunity of applying azobenzene-containing biomaterials as long-term "hot spring" dressings for wound treatment by only using light condition, widening the application scenarios of photoswitches-based solar thermal fuels.