Photothermally triggered double-layer hydrogels containing curcumin-loaded pullulan derivatives for controlled drug...

The development of advanced wound healing materials has garnered significant interest due to their potential to enhance therapeutic outcomes. This study presents a novel double-layer hydrogel system for the controlled release of curcumin under near-infrared (NIR) irradiation. The bottom layer, designed to incorporate curcumin, was formulated using pullulan conjugated with β-cyclodextrin and methacrylate (Pul-βCD-MA) in combination with poly(ethylene glycol) diacrylate (PEGDA). This combination significantly enhances curcumin solubility while improving the mechanical properties of the hydrogel. The top layer, composed of methacrylate-modified pullulan (Pul-MA) and polydopamine, serves as a photothermally responsive layer that converts NIR light into heat. The hydrogels were characterized by their morphology, mechanical properties, and drug release behavior. Upon NIR irradiation, the top-layer temperature increased to 40 °C, facilitating controlled release of curcumin from the bottom layer and yielding a cumulative release of 33 % under NIR, compared with 15 % in the absence of NIR. In vitro cell-migration assays demonstrated significantly enhanced wound closure when curcumin-loaded hydrogels were exposed to NIR irradiation. Biocompatibility with human dermal fibroblasts (HDFs) was confirmed, with no detectable cytotoxicity. This innovative double-layer hydrogel enables externally stimulus-responsive drug release and promotes effective wound healing. These findings position the double-layer hydrogel as a promising platform for advanced wound care with potential applications in controlled drug delivery.