A “signal-off” photoelectrochemical aptasensing for ATP based on Zinc Oxide/graphene nanocomposite prepared by graphene oxide’s catalytic decomposition performance towards zinc sulfateat low-temperature

Abstract

Abstract Optimization synthesis of semiconductor nanostructures with controlled crystallinity, size and morphology for improving inherent property of photoactive materials is crucial for achieving excellent PEC biosensor. Here, we tried to synthesize ZnO/graphene nanocomposite (ZnO/GR) via thermal decomposition using zinc sulfate and graphene oxide (GO) as starting materials. It was found that the annealing temperature greatly affects the phase transition and nanocrystallites size of the as-prepared nanostructure. Interestingly, the existence of GO can greatly decrease the decomposition temperature of zinc sulfate from 930°C to 530°C, solving the problem of zinc sulfate rarely used as a precursor for preparing ZnO because of its high decomposition temperature at 930°C. Further, we investigated the photoelectrochemical (PEC) behavior of these different nanostructures obtained under variety of temperatures. And the results indicated that nanocomposite obtained under temperature of 700°C have significant PEC efficiency, which was attributed to more uniform and well distributed nanocrystallite size and sulfur doping into the graphene under the temperature of 700°C. Finally, a “signal-off” PEC sensor was designed for Adenosine triphosphate (ATP) detection based on a ZnO/GR-700°C nanocomposite as photoactive materials and an ATP-binding aptamer as the recognition element. The proposed “signal-off” PEC aptasensing exhibited a wide linear range from 5 to 3000 nM with a low detection limit of 1.66 nM.