▎ 摘　　要

NOVELTY - Ultrasensitive electrochemical biosensor comprises MopRABCregulator protein immobilized on a novel graphene oxide based nanoplatform, where graphene oxide is coated on poly(3,4-ethylenedioxythiophene) (PEDOT):poly(styrenesulfonate) (PSS) layer. USE - Ultrasensitive electrochemical biosensor for detecting phenolic pollutants in samples, which is a wastewater sample from the environment or a simulated wastewater sample (claimed). ADVANTAGE - The ultrasensitive electrochemical biosensor detects phenolic pollutant in water sample accurately, quickly and with nanomolar level sensitivity and selectivity in real time, selectively and specifically senses harmful phenolic pollutant like phenol from a complex pollutant comprising chlorophenol, cresol, catechol, and xylenol, and detects phenolic compound comprising protein immobilized on a graphene oxide. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: an organic electrochemical transistor (OECT)-based biosensor device comprises source, drain and gate, where the gate electrode (G) is fabricated by a channel (PEDOT:PSS layer) and the PEDOT:PSS is further coated with graphene oxide, where the graphene oxide acts a platform for immobilizing the protein MopRABC regulator; a method for producing organic electrochemical transistor (OECT)-based biosensor device for detection of phenolic pollutants by fabricating the silver contact points with gate electrode (G) prepared with PEDOT:PSS material; coating the PEDOT:PSS layer with graphene oxide; and immobilizing the protein MopRABC regulator by physical adsorption onto the graphene oxide layer; and a method for detecting phenolic pollutants in samples by incubating the biosensor or OECT device with sample; assessing the bio-sensing ability of the biosensor towards phenol in the sample by using malachite green based colorimetric ATPase assay and monitoring spectrophotometrically at 630nm.