Surface-bound reactive oxygen species generating nanozymes for selective antibacterial action

Acting by producing reactive oxygen species (ROS) in situ, nanozymes are promising as antimicrobials. ROS' intrinsic inability to distinguish bacteria from mammalian cells, however, deprives nanozymes of the selectivity necessary for an ideal antimicrobial. Here we report that nanozymes that generate surface-bound ROS selectively kill bacteria over mammalian cells. This result is robust across three distinct nanozymes that universally generate surface-bound ROS, with an oxidase-like silver-palladium bimetallic alloy nanocage, AgPd0.38, being the lead model. The selectivity is attributable to both the surface-bound nature of ROS these nanozymes generate and an unexpected antidote role of endocytosis. Though surface-bound, the ROS on AgPd0.38 efficiently eliminated antibiotic-resistant bacteria and effectively delayed the onset of bacterial resistance emergence. When used as coating additives, AgPd0.38 enabled an inert substrate to inhibit biofilm formation and suppress infection-related immune responses in mouse models. This work opens an avenue toward biocompatible nanozymes and may have implication in our fight against antimicrobial resistance. Nanozymes have been used for antibacterial applications but have potential toxicity to mammalian cells. Here the authors suggest that nanozymes that generate surface bound reactive oxygen species disrupt bacterial cell walls but not mammalian cells walls due to the different particle uptake mechanisms.

Automated summary

The study shows that nanozymes that generate surface-bound ROS can selectively kill bacteria without harming mammalian cells, offering great potential for antimicrobial applications.