A Smart Antibacterial Surface for the On‐Demand Killing and Releasing of Bacteria

For various human healthcare and industrial applications, endowing surfaces with the capability to not only efficiently kill bacteria but also release dead bacteria in a rapid and repeatable fashion is a promising but challenging effort. In this work, the synergistic effects of combining stimuli‐responsive polymers and nanomaterials with unique topographies to achieve smart antibacterial surfaces with on‐demand switchable functionalities are explored. Silicon nanowire arrays are modified with a pH‐responsive polymer, poly(methacrylic acid), which serves as both a dynamic reservoir for the controllable loading and release of a natural antimicrobial lysozyme and a self‐cleaning platform for the release of dead bacteria and the reloading of new lysozyme for repeatable applications. The functionality of the surface can be simply switched via step‐wise modification of the environmental pH and can be effectively maintained after several kill–release cycles. These results offer a new methodology for the engineering of surfaces with switchable functionalities for a variety of practical applications in the biomedical and biotechnology fields.