Innovative Ag@Au nanozyme-enhanced organic photoelectrochemical transistor for ultrasensitive ochratoxin A detection

Organic bioelectronic devices are developing as adaptable platforms for advanced biosensing applications, such as wearable sensors, neural interfaces and tissue engineering, due to their remarkable flexibility, mobility, ease of manufacture, and biocompatibility. The article presents a unique organic photoelectrochemical transistor (OPECT) sensor, combined with an Ag@Au nanozyme-mediated catalytic precipitation mechanism, creating an ultrasensitive detection platform for Ochratoxin A (OTA). The ZnO/ZnFe₂O₄ heterostructure is established as a novel gating module. The ZnFe₂O₄ layer may boost electrolyte interaction and light accessibility to the ZnO nanoarray, thereby modulating the response of the polymeric poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) channel, which can be monitored through the channel current. In conjunction with aptamer sensing, the Ag@Au nanozyme, exhibiting peroxidase-mimicking activity, catalyzes the oxidation of 4-chloro-1-naphthol (4-CN), leading to the formation of an insoluble precipitate on the gate electrode surface, which diminishes the photocurrent and modifies the transistor response. The OPECT sensor demonstrates outstanding analytical capabilities for OTA, featuring a wide dynamic range from 10⁻⁵ ng/mL to 10 ng/mL and a detection limit of 0.0206 pg/mL. The advancement of this OPECT sensor offers potential for employing organic photoelectrochemical transistors as a high-performance platform for OTA detection.