CuO@PEDOT:PSS-grafted paper-based electrochemical biosensor for paraoxon-ethyl detection.

A highly sensitive, flexible, cheap, and biodegradable biosensor has been fabricated to detect paraoxon-ethyl (PE) more effectively. In this work, copper oxide (CuO) and poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS)-modified Whatman paper (WP)-based electrode are fabricated and then characterized by using different techniques. For the fabrication of CuO@PEDOT:PSS/WP electrode, firstly, the PEDOT:PSS/WP was optimized by various solvents such as ethylene glycol (EG), 1-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), N,N-dimethyl acetamide (NMA), and glycerol to enhance the conductivity. The EG-treated PEDOT:PSS/WP electrode shows maximum conductivity (1.4 × 10^{− 2} S cm^{− 1}) among all solvents. Further, the incorporation of CuO enhances the electrochemical performance of proposed biosensor. All electrochemical results validate that the proposed biosensor (AChE/CuO@PEDOT:PSS/WP) shows high sensitivity and low detection limit of 9.1279 µA/nM and 0.42 nM, respectively. The proposed paper electrode can be a highly promising alternative to conventional electrodes that are known to have limited applications due to their high cost and limited flexibility. The accuracy of the proposed biosensor was successfully checked in two real samples, which makes it more applicable for PE detection in real-world scenarios. [ABSTRACT FROM AUTHOR]