A Dual-Gate OECT Platform for Drift-Suppressed and High-Sensitivity Real-Time Biosensing
Organic electrochemical transistors (OECTs) enable high transconductance at low operating voltages through the volumetric charging of organic mixed ionic/electronic conductors (OMIECs), making them attractive transducers for biosensing. However, the same ionic -electronic coupling makes OMIECs, such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), sensitive to different ions and various environmental fluctuations, so drift and memory effects may compromise the quantitative readout in complex biofluids. In this work, we introduce a novel OECT-based sensor configuration that minimises drift by addressing a single channel with two gates: a functionalised sensing gate and a reference gate that allows real-time decoupling of environmental and channel-state fluctuations. A pulsed gate-biasing protocol is introduced to promote channel conductivity recovery and mitigate state accumulation. Using enzymatic glucose sensing as a proof of concept, the platform suppresses time-dependent drift by ~96%, eliminates temperature-induced variations up to 99% across the 20-70 {degrees}C range, improves calibrated sensitivity by 55% and reduces interferent-induced deviations under physiologically relevant conditions. By improving both signal stability and analytical reliability, this strategy addresses a central limitation of OECT biosensors and advances their use in high-sensitivity point-of-care biosensing in complex biological environments.