Near infrared light-triggered on-demand Cur release from Gel-PDA@Cur composite hydrogel for antibacterial wound healing

The development of antibacterial and rapid hemostatic wound dressing with good biocompatibility is urgently required for promoting non-healing wounds. In this work, a multifunctional near infrared (NIR) laser-induced hydrogel for infected wound healing is presented. The hydrogel was composed of dibenzaldehyde-grafted poly (ethylene glycol) (PEGDA), lauric acid-terminated chitosan (Chi-LA), and curcumin (Cur)-loaded mesoporous polydopamine nanoparticles (PDA@Cur) via Schiff base and/or Michael addition reaction. The Cur could rapidly release from Gel-PDA@Cur hydrogel under NIR laser irradiation with on-demand release property. Meanwhile, NIR irradiation could activate the photothermal PDA NPs in Gel-PDA@Cur hydrogel and generate local hyperthermia for killing Escherichia coli and Staphylococcus aureus. It was realized by inducing the “out-diffusion” of K⁺, inactivating the respiratory chain dehydrogenase and β-galactosidase activity, causing cellular components leakage (protein, DNA and RNA, etc.), reducing the ATP level, and destroying bacterial membrane. Moreover, the Gel-PDA@Cur hydrogel exhibited good biocompatibility. Furthermore, in vivo treatment in a S. aureus-infected full-thickness skin defect model revealed that the Gel-PDA@Cur hydrogel presented good hemostatic function, prominent antibacterial ability, strong anti-inflammatory effect, and good wound healing capacity.