Milk-Derived Injectable Wound Dressing with Sequential Photoactivatable Antibacterial Property through In Situ Biomineralization.

The emergence of drug-resistant bacteria due to excessive antibiotic use has drawn increasing attention to inorganic nanoparticles for their broad-spectrum antibacterial properties. Here, a "green" strategy for the simultaneous in situ synthesis of silver nanoparticles (AgNPs) during the photocrosslinking process of casein hydrogels is described. The in situ photoactivated biomineralization of AgNPs provides noticeable stability and antibacterial activity, with high photothermal effect during a sequential near-infrared laser activation. The milk-derived casein is screened out due to its great biomineralization capability and wound healing activity. Casein-AgNP hydrogel dressing shows low swelling, good mechanical properties, and nice biocompatibility. In animal experiments, casein-AgNP hydrogel accelerates wound repair and tissue regeneration after bacterial infection by regulating immune response. Our work shows that sequential photoactivation served as a promising strategy for antiinfectious wound treatment, and casein hydrogel stood as a potential candidate for in situ biomineralization.