Keene, S. T. | bioRxiv Science

bioRxiv2026

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.

bioengineering↗

bioRxiv2022

Pulsed transistor operation enables miniaturization of electrochemical aptamer based sensors

By simultaneously transducing and amplifying, transistors offer advantages over simpler, electrode-based transducers in electrochemical biosensors. However, transistor-based biosensors typically use static (i.e., DC) operation modes that are poorly suited for sensor architectures relying on the modulation of charge transfer kinetics to signal analyte binding. Thus motivated, here we translate the AC "pulsed potential" approach typically used with electrochemical aptamer-based sensor to an organic electrochemical transistor (OECT). Specifically, by applying a linearly sweeping square-wave potential to an aptamer-functionalized gate electrode, we produce current modulation across the transistor channel two orders of magnitude larger than seen for the equivalent, electrode-based biosensor. Critically, the resulting amplification is scalable, such that there is no signal loss with OECT miniaturization. The pulsed transistor operation demonstrated here could be applied generally to sensors relying on kinetics-based signaling, expanding opportunities for non-invasive and high spatial resolution biosensing.

bioengineering↗