Acetylcholinesterase-assisted photoelectrochemical solution gated graphene field-effect transistor for organophosphates pesticide detection.

This study develops a photoelectrochemical solution-gated graphene field-effect transistor (PEC-SGGT) for ultrasensitive organophosphates (OPs) detection, merging optoelectronic modulation with enzymatic signal amplification. The sensor employs a hybrid system of cadmium sulfide quantum dots (CdS QDs) and acetylcholinesterase (AChE), using acetylthiocholine (ATCh) as the substrate. Under light, CdS QDs generate electron-hole pairs, while AChE hydrolyzes ATCh into thiocholine (TCh), which enhances charge separation and amplifies photocurrent. OPs-induced inhibition of AChE reduces TCh production, decreasing photocurrent and enabling PEC-SGGT gate-controlled OPs quantification. The sensor achieves a detection limit of 0.21 pM and a linear range of 0.1 nM to 1 mM. This work demonstrates the potential of light-assisted, enzyme-functionalized, gate-modulated PEC-SGGT systems for diverse biosensing applications, including enzymatic sensors, enzyme-labeled immunosensors, and enzyme-labeled DNA biosensors, advancing bioelectronics.