A bifunctionalized NiCo2O4-Au composite: Intrinsic peroxidase and oxidase catalytic activities for killing bacteria and disinfecting wound

A NiCo 2 O 4 -Au composite was fabricated following the calcination-reduction method and testified to exhibit the intrinsic high peroxidase- and oxidase-like activities. The composite could activate a low level of H 2 O 2 (100 μM) to kill E. coli and S. aureus . NiCo 2 O 4 -Au composite could be easily separated by an external magnet from the media and reused several times. NiCo 2 O 4 -Au composite could also effectively damage the existing biofilms and prevent the formation of new biofilms. The electron spin resonance tests showed that NiCo 2 O 4 -Au composite catalyzed H 2 O 2 into reactive oxygen species (ROS), mainly including OH, O 2 − , and 1 O 2 ; while the oxidase-like activity of NiCo 2 O 4 -Au also stemmed from the ROS formation in the absence of H 2 O 2 . The radical trapping experiment confirmed that O H and 1 O 2 were the main radicals in the antibacterial process for NiCo 2 O 4 -Au in the presence of H 2 O 2 . A NiCo 2 O 4 -Au based Band-Aid was also designed, which exhibited high anti-infective and wound-healing properties. This study has demonstrated that NiCo 2 O 4 -Au composite can be a promising antibacterial agent in environmental and clinical applications.