Dual-substrate, dual-mode and self-powered visual biosensor based on biofuel cell

While lots of diseases and foods are related to two substrates, self-powered dual-substrate detection remains a great challenge. Here, we propose a portable self-powered visual biosensor based on a dual-substrate enzyme biofuel cell (EBFC) for glucose and ethanol detection. The integration of electrochemical and visual sensing can not only realize dual-substrate analysis but also implement dual-mode detection. The employed dual-substrate EBFC is composed of an alcohol dehydrogenase-based bioanode and a glucose oxidase/Prussian blue (PB) coupled biocathode. Since the proper redox potential and outstanding electrochromic property, PB serves as both the display screen for visual analysis and the biocathode for power generation. The constructed self-powered visual biosensor has wide detection range and low detection limit toward glucose and ethanol biosensing. Notably, the PB display screen could be recovered by the biosensor itself, making the biosensor reusable, integrating and miniaturization. For real sample analysis, glucose in serum and ethanol in wine can be successfully detected by visual inspection. In the meantime, the self-powered visual biosensor can distinguish different actual samples containing both glucose and ethanol. These further broaden the application range of self-powered biosensor and provide new insight for multiple substrates detection.