CuS nanoenzyme against bacterial infection by in situ hydroxyl radical generation on bacteria surface

Nanoenzyme-mediated antibacterial strategies have been widely exploited to overcome the shortcomings (such as drug resistance and mild-to-severe side effects) of antibiotic therapy. The peroxidase-like activity of nanoenzymes possesses great potential against bacterial infection by the generation of hydroxyl radical (·OH) in the specific microenvironment. However, the lifetime of ·OH is extremely short, and a large amount of the ·OH generated within the infection microenvironment cannot come into contact with bacteria quickly enough, thus resulting in low treatment efficiency. Here, chitosan-oligosaccharide-modified CuS nanoparticles possessing positive charges (PCuS NPs) were prepared using a one-pot method. PCuS NPs exhibited efficient peroxidase-like activity. Importantly, the PCuS NPs can combine with bacteria via electrostatic attraction. The direct contact between the PCuS NPs and bacteria enabled the generation of ·OH in situ on the bacterial surface, ultimately leading to a high antibacterial efficacy at a low concentration in the presence of H 2 O 2 . At an effective antibacterial concentration, the PCuS NPs exhibited high cytocompatibility. Furthermore, in vivo results revealed that PCuS NPs not only decreased the size of abscesses but also reduced inflammation and promoted collagen fiber formation. Therefore, PCuS NPs possess great potential against bacterial infection via in situ ·OH generation based on electrostatic attraction. Graphical abstract