Biocompatible N-carbazoleacetic acid decorated CuxO nanoparticles as self-cascading platforms for synergistic single near-infrared triggered phototherapy treating microbial infections

Abstract

In this work, positively charged N-carbazoleacetic acid decorated Cu_xO nanoparticles (Cu_xO-CAA NPs) as novel biocompatible nanozymes have been successfully prepared through a one-step hydrothermal method. Cu_xO-CAA can serve as a self-cascading platform through effective GSH-OXD-like and POD-like activities, and the former can induce continuous generation of H₂O₂ through the catalytic oxidation of overexpressed GSH in the bacterial infection microenvironment, which in turn acts as a substrate for the latter to yield ˙OH via Fenton-like reaction, without introducing exogenous H₂O₂. Upon NIR irradiation, Cu_xO-CAA NPs possess a high photothermal conversion effect, which can further improve the enzymatic activity for increasing the production rate of H₂O₂ and ˙OH. Besides, the photodynamic performance of Cu_xO-CAA NPs can produce ¹O₂. The generated ROS and hyperthermia have synergetic effects on bacterial mortality. More importantly, Cu_xO-CAA NPs are more stable and biosafe than Cu₂O, and can generate electrostatic adsorption with negatively charged bacterial cell membranes and accelerate bacterial death. Antibacterial results demonstrate that Cu_xO-CAA NPs are lethal against methicillin-resistant Staphylococcus aureus (MRSA) and ampicillin-resistant Escherichia coli (AREC) through destroying the bacterial membrane and disrupting the bacterial biofilm formation. MRSA-infected animal wound models show that Cu_xO-CAA NPs can efficiently promote wound healing without causing toxicity to the organism.