Organic photoelectrochemical transistor biosensor based on BiVO₄-ZnIn₂S₄ material for efficient and sensitive...

Recently, organic photoelectrochemical transistor (OPECT) has become a very interesting biological measurement method in photoelectrochemical (PEC) bioanalysis and future bio-related applications. OPECT is expected to be a powerful tool for disease detection and early warning. Circulating tumor cells (CTCs) are generally deemed to be the dominant factor of tumor metastasis, and 90 % of cancer patients die from this metastatic disease. Therefore, there is an imminent need to develop a highly sensitive CTCs detection sensing system to improve the survival rate of cancer patients. Here, we use a DNA tetrahedrons (DNA NTH) with an aptamer at the top to immobilize on the surface of the photoelectric material to capture cells (MCF-7). Specifically, the BiVO₄-ZnIn₂S₄ hybrid was synthesized by a simple hydrothermal method, which can effectively modulated devices with high current gain. Au NPs were directly integrated on the electrode surface to construct an OPECT photoelectric sensing platform. Subsequently, the aptamer which is thiol-functionalized (SH-Apt) was immobilized on the electrode surface. Because of the overexpression of MUC1 protein on the cell membrane, it can specifically capture MCF-7 cells. The introduction of MCF-7 cells resulted in a significant decrease in the current signal. There is a relationship between the change of photocurrent and the logarithm of MCF-7 cell concentration, which is a good linear relationship ranging from 50 to 5 × 10⁵ cell mL^-1. The obtained detection limit is 43 cell mL^-1. The biosensor has high selectivity and sensitivity, and achieves sensitive detection of MCF-7.