Enzymatically Mediated In Situ Generation of Z-Scheme BiS/BiMoO Heterojunction-Based Organic Photoelectrochemical Transistor for METTL3/METTL14 Detection.

The OPECT biosensing platform, which connects optoelectronics and biological systems, offers significant amplification and more possibilities for research in biological applications. In this work, a homogeneous organic photoelectrochemical transistor (OPECT) biosensor based on a BiS/BiMoO heterojunction was constructed to detect METTL3/METTL14 protein activity. The METTL3/METTL14 complex enzyme was used to catalyze adenine (A) on an RNA strand to mA, protecting mA-RNA from being cleaved by an toxin (MazF). Alkaline phosphatase (ALP) catalyzed the conversion of NaSPO to HS through an enzymatic reaction. Due to the adoption of the strategy of no fixation on the electrode, the generated HS was easy to diffuse to the surface of the ITO electrode. The BiS/BiMoO heterojunction was formed in situ through a chemical replacement reaction with BiMoO, improving photoelectric conversion efficiency and realizing signal amplification. Based on this "signal on" mode, METTL3/METTL14 exhibited a wide linear range (0.00001-25 ng/μL) between protein concentration and photocurrent intensity with a limit of detection (LOD) of 7.8 fg/μL under optimal experimental conditions. The applicability of the developed method was evaluated by investigating the effect of four plasticizers on the activity of the METTL3/METTL14 protein, and the molecular modeling technique was employed to investigate the interaction between plasticizers and the protein.