An integrated 3D cell-based electrochemical biosensor for neurotoxicity assessment of organophosphorus pesticides

This work presents an integrated three-dimensional (3D) cell-based electrochemical biosensor to assess the neurotoxicity of organophosphorus pesticides (OPs). In this system, OPs inhibit the activity of intracellular acetylcholinesterase (AChE), and thus the enzymatic hydrolysate 1-naphthol (1-N) presents a declining trend. The fluctuation of the 1-N electrochemical response is proved to be a reliable indicator to evaluate the OPs neurotoxicity. Gelatin methacrylate hydrogel is introduced as a scaffold for the 3D culture of PC12 cells, providing an in vivo-like environment for toxicological evaluation. Meanwhile, zeolite imidazolate framework-67@CoAl layered double hydroxides/multi-walled carbon nanotube composites devolve the screen-printed carbon electrode with significant sensitivity. The cell culture and electrochemical detection processes are integrated into a 3D-printed platform, facilitating the portability and timeliness of testing. Under optimal experimental conditions, the detection limit and linear range of 1-N are found as 0.148 μM and 0.5–150 μM, respectively. The proposed sensor is applied to assess the neurotoxicity of three typical OPs (chlorpyrifos, dimethoate, and isocarbophos), and the results are further confirmed with the conventional Ellman's method. With the comparatively high sensitivity, reliability, and simplicity provided, the fabricated sensor exhibits broad prospects in the field of neurotoxicity evaluation.