Potentiometric Acetylcholine Biosensor Based on Molybdenum Trioxide Film-Modified Tungsten Trioxide Nanoparticles and Dual-Enzyme

In this study, we introduce a novel potentiometric biosensor for acetylcholine detection that integrates molybdenum oxide, tungsten trioxide nanoparticles, and dual enzymes: acetylcholinesterase and choline oxidase. This biosensor represents a new application of metal oxides in acetylcholine detection, showcasing the hydrothermal synthesis of tungsten trioxide nanoparticles. Their successful synthesis was confirmed via X-ray diffraction. The molybdenum trioxide (MoO3) film was deposited on a flexible printed circuit board (FPCB) through radio frequency sputtering and further modified with tungsten trioxide nanoparticles, acetylcholinesterase, and choline oxidase to significantly enhance the biosensor’s performance, exhibiting high sensitivity, rapid response, high selectivity, and low detection limit. The surface and thickness were characterized by field emission scanning electron microscopy. Experimental results demonstrate that the modified acetylcholine biosensor exhibits an exceptional sensitivity of 60.79 mV/decade across a concentration range of 0.01–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100~\mu $ </tex-math></inline-formula> M.