MXene-TiO₂-based photocatalytic fuel cell with bioresponsive controlled glucose release system: An innovative mode...

Self-powered photocatalytic fuel cell (PFC)-based sensors incorporating bioelement recognition with fuel concentration-dependent output power have been developed for electrochemical analysis, but most involve poor energy conversion efficiency and are unsuitable for routine use. Herein, a self-powered and self-checking PFC bioanalysis platform under visible light for ultrasensitive screening of Ochratoxin A (OTA) was designed. Specifically, the self-powered photocatalytic fuel cell-based sensor was comprised of a photoanode fabricated with MXenes (Ti₃C₂)-TiO₂ and a cathode modified with Prussian blue (PB). To realize the high-performance of OTA detection, mesoporous silica nanoparticles (MSNs) were used as nanocontainers to load glucose, and aptamers were assembled on the surface of MSNs as dual-gated molecules to form signal probes. The reaction of analyte OTA with OTA aptamer was greater than the force between OTA aptamer and MSN, resulting in the release of glucose from MSNs. The released glucose was photo-oxidized by Ti₃C₂-TiO₂ under visible light illumination and used as an electron acceptor to reduce PB, resulting in a high cell output response with a maximum output power (P_max) of 23.516 μW cm^-2. Meanwhile, the electrochromic PB enabled colorimetric detection of OTA with self-checking. The self-powered Ti₃C₂-TiO₂-based PFC with target-recognition cargo release system exhibited superior analytical performance toward OTA in the range of 0.2 ppb-20 ppb and limit of detection (LOD) down to 0.0587 ppb. Additionally, excellent stability, rapid response, and exquisite selectivity for real samples (beer) was acceptable, providing an efficient approach in food safety monitoring.