Hybridization Chain Reaction-Enhanced Biocatalytic Precipitation on Flower-like Bi 2 S 3 : 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 Bi 2 S 3 photosensitive gate for high-efficacy OPECT operation with high transconductance ( g m ), 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 g m 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 ( I DS ). 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.