Self-powered aptasensor for picomole level pollutants based on a novel enzyme-free photofuel cell

Atrazine (ATZ) is a highly toxic chlorine-containing aromatic structural triazine endocrine disruptor. Due to its chemical stability and electrochemical inertness, it is of great challenge and significance to establish a simple, portable, and in situ electrochemical sensor for ATZ. In the present work, a self-powered aptasensor (SPA) based on a novel enzyme-free photofuel cell (PFC) is successfully developed for ATZ for the first time. The designed SPA is constructed by the Ti-Fe-O nanotubes/nickel hydroxide (Ti-Fe-O NTs/Ni(OH)₂) photoanode and Au/aptamer (Au/Apt) cathode, responsible for the spontaneous generation of electrons and specific recognition of ATZ, respectively. It is worth noting that Ti-Fe-O NTs on the photoanode can exhibit good visible-light absorption property, and modified Ni(OH)₂ further enhances the photo-generated carrier separation and improves the output power generation of the SPA. The recognition is set at the cathode to ensure the detection of ATZ and the anti-interference ability. Under the separation mode, the constructed SPA has a high output power (390 μW cm^-2), much better than most previous reports. It can further show specific recognition of ATZ with prominent sensitivity and a limit of detection (LOD) as low as 5.4 pM. Moreover, it has been applied to the real water sample analysis with satisfactory results. A promising self-powered sensing platform based on an enzyme-free PFC has therefore been provided for picomole level pollutants with high sensitivity and outstanding selectivity.