Nanocomposite of Ag nanoparticles and deep eutectic solvent‐derived carbon dots with oxidase mimicking activity as synergistic bactericidal agent.

A new type of nitrogen and chloride co‐doped carbon dots (N/Cl‐CDs) based on choline chloride–urea–glycine ternary deep eutectic solvents (DESs) was synthesized using a one‐step hydrothermal method. The prepared N/Cl‐CDs exhibited oxidase‐like activity and excellent antibacterial activity against Escherichia coli, Staphylococcus aureus and methicillin‐resistant Staphylococcus aureus (MRSA). The addition of silver nanoparticles (Ag NPs) (i.e. N/Cl‐CDs + Ag NPs) to the N/Cl‐CDs also significantly enhanced the oxidase and antibacterial activities. The nanocomposite (1·8 mg ml−1) completely inactivated 105 CFU per ml of MRSA in 90 min. E. coli and S. aureus were labelled with the N/Cl‐CDs, enabling multicolour fluorescence imaging at different excitation wavelengths. The nanocomposites have high antibacterial efficiency as a new bactericidal agent, as well as application potential with good biocompatibility and low toxicity. [ABSTRACT FROM AUTHOR]