Simultaneous Multiparameter Detection with Organic Electrochemical Transistors-Based Biosensors

We present a methodology that enhances the analytical performance of organic electrochemical transistors (OECTs) by continuously cycling the devices through gate-potential sweeps during sensing experiments. This continuous cycling method (CCM) enables real-time acquisition of full transfer curves, allowing simultaneous monitoring of multiple characteristic parameters. We show that the simultaneous temporal evolution of several OECT response parameters (VTH, VG,gmax, and gmax) provides highly sensitive descriptors for detecting pH changes and macromolecule adsorption on OECTs based on PANI and PEDOT channels. Moreover, the method allows reconstruction of IDS–time profiles at any selected gate potential, enabling the identification of optimal VG values for maximizing sensitivity. This represents a substantial improvement over traditional measurements at fixed VG, which may suffer from reduced sensitivity and parasitic reactions associated with gate polarization. Moreover, the expanded set of parameters obtained with the CCM provides deeper insight into the physicochemical processes occurring at both gate and channel electrodes. We demonstrate its applicability to monitoring polyelectrolyte and enzyme adsorption as well as detecting urea and glucose through enzyme-mediated reactions. Owing to its versatility and the richness of the information it provides, the CCM constitutes a significant advance for the development and optimization of OECT-based sensing platforms.