A radical eliminating and antibacterial dual-functional nanomedicine: Epigallocatechin-3-gallate-coated Prussian blue decorated polydopamine nanoparticles for wound healing

Bacterial infection and excessive production of free radicals, including reactive oxygen species (ROS), reactive nitrogen species (RNS), are the main factors for impaired wound healing. Development of a nanomedicine with antibacterial, antioxidant, and anti-inflammatory activities is a promising treatment modality for infected wounds. Herein, we fabricated a versatile nanomedicine with antibacterial and free radical eliminating properties through a facile layer-by-layer strategy. Polydopamine nanoparticles (PDA NPs) were first prepared as core materials, followed by in situ formation of Prussian blue (PB) and coating with epigallocatechin-3-gallate (EGCG)-derived polymer layer successively, resulting in a core-shell structured nanomedicine (designated as PDA@PB@EGCG). The integration of PDA core and uniformly decorated PB endowed as-prepared PDA@PB@EGCG with excellent NIR-triggered photothermal properties. In addition, owing to the multi-enzymatic activity of PB and potent antioxidant capacity of PDA and EGCG, PDA@PB@EGCG with robust ROS/RNS-eliminating properties exhibited a strong cytoprotective effect against oxidative damage. Under near-infrared (NIR) laser irradiation (808 nm, 1.5 W/cm 2 ), PDA@PB@EGCG (50 μg/mL) displayed a robust and broad-spectrum bactericidal activity against Escherichia coli ( E . coli ) and Staphylococcus aureus ( S . aureus ). In vivo therapeutic efficacy was evaluated using a S . aureus -infected rat model, indicating PDA@PB@EGCG could effectively eliminate bacteria, modulate the infectious microenvironment and promote wound healing.