An electrochromic platform based on bacteria-semiconductor interactions for visual bacterial detection and inhibition

Early identification of bacteria and timely intervention are crucial for human health and public safety. However, conventional detection and antibacterial systems are usually separate, which hinders the integration of real-time monitoring with active intervention. In this work, a three-dimensionally ordered macroporous tungsten trioxide (3DOM WO 3 ) electrochromic material was constructed via a template-assisted method, enabling integrated visual detection and antibacterial intervention. Benefiting from the high specific surface area, abundant interfacial active sites, and enhanced mass/electron transport associated with the 3DOM architecture, 3DOM WO 3 exhibited superior bacterial responsiveness compared with conventional WO 3 . Using Escherichia coli and Staphylococcus aureus as model bacteria, 3DOM WO 3 generated pronounced electrochromic responses, with the color change correlating well with bacterial concentration, providing an intuitive method for visual detection. Meanwhile, plate counting and live/dead bacterial staining demonstrated that 3DOM WO 3 exhibited stronger antibacterial activity than WO 3 against both bacterial strains. Mechanistic studies revealed that electron transfer at the bacteria-semiconductor interface, triggered by the respiratory metabolism of live bacteria, induced the reduction of 3DOM WO 3 and promoted reactive oxygen species generation, thereby producing both electrochromic signals and antibacterial effects. This work proposes an electrochromic strategy based on bacteria-semiconductor interfacial electron transfer, offering a novel approach for smart material platforms that integrate real-time visual monitoring with active antibacterial functions.