Silk-based mesoporous thermo-adaptive injectable Au–TiO2/ICG nanoengineered hydrogel system for NIR-triggered antibacterial and wound healing applications

Infection and chronicity of wounds pose an intimidating problem in clinical practice, necessitating a system that would be able to dynamically adjust to the changes in the wound bed, delivering antibacterial effects and monitoring them simultaneously. Herein, a thermo-adaptive injectable hydrogel using Au–TiO 2 –PF127–ICG (ATI) nanocomposites loaded in a silk hydrolysate-PEG 400 -gelatin (SPG) matrix has been developed, integrating mechanical adaptability, phototherapy, biocompatibility, and imaging functionality in a single construct. The hydrogel is stable at room temperature while undergoing gel-sol phase transition at physiological temperature, thus allowing simple injection and in situ shaping within irregular wounds. Rheological analysis confirmed a distinct gel–sol transition near physiological temperature, validating its thermo-adaptive nature. Upon NIR 808 irradiation, the incorporated indocyanine green (ICG) efficiently converted light into heat, while the Au–TiO 2 nanocomposites along the ICG produced reactive oxygen species (ROS), resulting in a dual photothermal/photodynamic antibacterial effect against E. coli and S. aureus . Infrared thermal imaging and IVIS fluorescence visualization further confirmed localized photothermal responsiveness and sustained hydrogel retention at the wound site, enabling fluorescence-assisted image-guided localization and monitoring. Furthermore, in vivo studies revealed accelerated wound closure, enhanced collagen deposition, and favorable histological regeneration under NIR stimulation, signifying the hydrogel's regenerative potential. Overall, this ATI-SPG hydrogel demonstrates a harmonious combination of injectability, self-adaptivity, fluorescence-enabled image-guided localization, NIR-triggered multimodal antibacterial therapy, and wound healing capability, providing a promising platform for next-generation light-responsive materials for wound management.