A split organic photophotochemical transistor/vision sensing platform based on MNZ composite and ZIF-67/CuCoO nanospheres for ultra-sensitive detection of CEA.

In this study, a novel organic photophotochemical transistor (OPECT) biosensing platform was proposed for dual-mode detection of CEA. The dual-mode detecting system is achieved benefit from the exceptional photoelectric performance of MIL-53(Fe) -NH@ZnInS (MNZ) and the peroxidase enzyme (POD) activity of ZIF-67/CuCoO (ZIF-67/CuCoO). Ab2- ZIF-67/CuCoO probe was immobilized on a 96-well plate by enzyme-linked immunosorbent assay, which accelerated the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) by hydrogen peroxide and thus successfully realized visual detection of CEA. Additionally, in OPECT biosensing mode, the oxidized form of TMB (oxTMB·) serves as a consumptive agents of the electron donor AA, which cause the photocurrent change of MNZ heterojunction, leading to a decrease in the channel current of poly (ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) organic transistor. The integration of nanobiocatalysts and the OPECT system demonstrates excellent detection performance for CEA, with a detection limit as low as 3.24 fg mL and expanded their prospective applications for clinical detection of nucleic acids, proteins, and other tumor markers.