Reticular Heterojunction for Organic Photoelectrochemical Transistor Detection of Neuron‐Specific Enolase

Reticular heterojunctions on the basis of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) have sparked considerable interest in recent research endeavors, which nevertheless have seldom been studied in optoelectronic biosensing. In this work, its utilization for organic photoelectrochemical transistor (OPECT) detection of the important cancer biomarker of neuron‐specific enolase (NSE) is reported. A MOF@COF@CdS quantum dots (QDs) heterojunction is rationally designed to serve as the photogating module against the polymeric channel. Linking with a sandwich complexing event, target‐dependent alternation of the photogate is achieved, leading to the changed photoelectric conversion efficiency as indicated by the amplified OPECT signals. The proposed assay demonstrates good analytical performance in detecting NSE, featuring a linear detection range from 0.1 pg mL−1 to 100 ng mL−1, with a detection limit of 0.033 pg mL−1. Based on MIL‐68‐NH2@COFTP‐TA@CdS reticular heterojunction, a photoelectrode‐gated OPECT biosensor is presented, which is exemplified by the Cu2+‐triggered electron trap formation linking with a sandwich immunoassay. The reticular heterostructure enhances the regulation of the channel by the photosensitive gate. At zero gate bias, this OPECT biosensor exhibits high gain in response to light and good analytical performance for NSE.