Integrating organic photoelectrochemical transistor with nanozyme-mediated reaction for ultrasensitive tobramycin detection

Organic bioelectronic devices are emerging as versatile platforms for next-generation biosensing applications, including wearable sensors, tissue engineering, and neural interfaces, owing to their exceptional flexibility, portability, facile fabrication, and biocompatibility. This manuscript introduces a novel organic photo- electrochemical transistor (OPECT) sensor, which is integrated with Au@PdAg nanozyme-mediated catalytic precipitation process, establishing an ultrasensitive detection platform for Tobramycin (TOB). Herein, ZnIn2S4/ TiO2 heterostructure as innovative gating module is realized. Specifically, the upper ZnIn2S4 layer could result into an enhanced electrolyte contact and light accessibility to TiO2 nanoarray, leading to the modulated response of the polymeric poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) channel that could be monitored by the channel current. Linking with aptamer sensing, the Au@PdAg nanozyme with peroxidasemimicking activity can catalyze the oxidation of 4-chloro-1-naphthol (4-CN) to form an insoluble precipitate on the gate electrode surface, resulting in a decrease in the photocurrent and altering the transistor response. This OPECT sensor showcases exceptional analytical performance for TOB, with a broad dynamic range from 0.1 pM to 100 nM and a detection limit as low as 0.18 pM. The development of this OPECT sensor presents prospects for using organic photoelectrochemical transistors as a high-performance platform for detecting antibiotics.