Cuprous oxide-demethyleneberberine nanospheres for single near-infrared light-triggered photoresponsive-enhanced enzymatic synergistic antibacterial therapy.

In this work, novel cuprous oxide-demethyleneberberine (CuO-DMB) nanomaterials are successfully synthesized for photoresponsive-enhanced enzymatic synergistic antibacterial therapy under near-infrared (NIR) irradiation (808 nm). CuO-DMB has a spherical morphology with a smaller nanosize and positive potential, can trap bacteria through electrostatic interactions resulting in a targeting function. CuO-DMB nanospheres show both oxidase-like and peroxidase-like activities, and serve as a self-cascade platform, which can deplete high concentrations of GSH to produce O˙ and HO, then HO is transformed into ˙OH, without introducing exogenous HO. At the same time, CuO-DMB nanospheres become photoresponsive, producing O and having an efficient photothermal conversion effect upon NIR irradiation. The proposed mechanism is that the generated ROS (O˙, ˙OH and O) and hyperthermia can have synergetic effects for killing bacteria. Moreover, hyperthermia is not only beneficial for destroying bacteria, but also effectively enhances the efficiency of ˙OH production and accelerates GSH oxidation. Upon NIR irradiation, CuO-DMB nanospheres exhibit excellent antibacterial ability against methicillin-resistant () and ampicillin-resistant () with low cytotoxicity and bare bacterial resistance, destroy the bacterial membrane causing an efflux of proteins and disrupt the bacterial biofilm formation. Animal experiments show that the CuO-DMB + NIR group can efficiently treat infection and promote wound healing. These results suggest that CuO-DMB nanospheres are effective materials for combating bacterial infections highly efficiently and to aid the development of photoresponsive enzymatic synergistic antibacterial therapy.