Photothermal-triggered release of alkyl radicals hydrogel via versatile carbon dots chelating Ag+ and its synergistic anti-bacterial and biofilm activities

Staphylococcus aureus has become one of the most common pathogens in clinical tissue infection, and it is easy to form biofilm. Incomplete removal of biofilms often leads to recurrent infections, and more serious is the possibility of bacteria developing drug resistance. Therefore, the effective eradication of refractory biofilms is essential. Herein, a temperature-sensitive hydrogel was prepared by doping the photothermal carbon dots (PTCDs) chelated by Ag+, and the AIPH which can produce alkyl radicals in response to heat into the thermodissolved gelatin. Under the irradiation of 660 nm laser, the PTCDs generate heat to dissolve the hydrogel, and prompting chelation of silver ions in PTCDs for chemical sterilization. Meanwhile, the heat generated by the PTCDs induce the 2,2′-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIPH) to produce alkyl free radical sterilization, achieving the purpose of photothermal/thermodynamic/chemical synergistic to kill Staphylococci aureus and destroy its biofilm. Therefore, the biocompatible PTCDs@Ag-AIPH hydrogel proposed in this study is a promising composite that can eliminate biofilms and promote wound healing, showing good potential in future biomedical applications.