Hybrid ZnO@Au Nanorod Array for Fast and Repeatable Bacteria Inactivation

The worldwide abuse of antibiotics and resultant antimicrobial resistance made the development of new antibacterial materials an urgent and significant issue. Herein, a hybrid ZnO@Au nanorod array with fast bacterial inactivation and excellent recyclability was reported. 93% bacteria could be inactivated within 5 min ultra-sonication under indoor daylight, and the killing rate maintains above 90% after seven repeated using cycles. Antibacterial mechanism involves extracellular reactive oxygen species (ROS) generated from photocatalysis and piezoelectricity of nanorod array, intracellular ROS generation and decrease of adenosine-triphosphate (ATP) originated from electron transfer (ET) from bacteria to nanorod array, as well as mechanical effect from the nanorod, among which ET mechanism plays a major role. Large Schottky barrier from the hybrid interface not only enhances the ROS generation by promoting the charge transfer and carrier separation as well as light utilization, but also enables one-direction electron transfer from bacteria to nanorod array. The resultant continuous electron loss breaks the energy metabolism and disturbs the redox equilibrium, leading to bacterial death. This study demonstrates the great potential of hybrid structure in antibacterial applications and indicates ET as a novel effective antibacterial mechanism for semiconductor materials, which provides insights into the design of next-generation antibacterial materials.