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

In this work, novel cuprous oxide-demethyleneberberine (Cu 2 O-DMB) nanomaterials are successfully synthesized for photoresponsive-enhanced enzymatic synergistic antibacterial therapy under near-infrared (NIR) irradiation (808 nm). Cu 2 O-DMB has a spherical morphology with a smaller nanosize and positive ζ potential, can trap bacteria through electrostatic interactions resulting in a targeting function. Cu 2 O-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 2 ˙ - and H 2 O 2 , then H 2 O 2 is transformed into ˙OH, without introducing exogenous H 2 O 2 . At the same time, Cu 2 O-DMB nanospheres become photoresponsive, producing 1 O 2 and having an efficient photothermal conversion effect upon NIR irradiation. The proposed mechanism is that the generated ROS (O 2 ˙ - , ˙OH and 1 O 2 ) 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, Cu 2 O-DMB nanospheres exhibit excellent antibacterial ability against methicillin-resistant Staphylococcus aureus ( MRSA ) and ampicillin-resistant Escherichia coli ( AREC ) 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 Cu 2 O-DMB + NIR group can efficiently treat MRSA infection and promote wound healing. These results suggest that Cu 2 O-DMB nanospheres are effective materials for combating bacterial infections highly efficiently and to aid the development of photoresponsive enzymatic synergistic antibacterial therapy.