Hybridization Chain Reaction-Enhanced Biocatalytic Precipitation on Flower-like Bi2S3: Toward Organic Photoelectrochemical Transistor Aptasensing with High Transconductance

Organic photoelectrochemical transistor (OPECT) bioanalysis has recently emerged as a promising avenue for biomolecular sensing, providing insight into the next-generation of photoelectrochemical biosensing and organic bioelectronics. Herein, this work validates the direct enzymatic biocatalytic precipitation (BCP) modulation on a flower-like Bi2S3 photosensitive gate for high-efficacy OPECT operation with high transconductance (gm), which is exemplified by a prostate-specific antigen (PSA)-dependent hybridization chain reaction (HCR) and subsequent alkaline phosphatase (ALP)-enabled BCP reaction toward PSA aptasensing. It has been shown that light illumination could ideally achieve the maximized gm at zero gate bias, and BCP could efficiently modulate the device's interfacial capacitance and charge-transfer resistance, resulting in a significantly changed channel current (IDS). The as-developed OPECT aptasensor realizes good analysis performance for PSA with a detection limit of 10 fg mL–1. This work features direct BCP modulation of organic transistors and is expected to stimulate further interest in exploring advanced BCP-interfaced bioelectronics with unknown possibilities.