A paper-based organic electrochemical transistor array with a simplified configuration for simultaneous multi-ion detection

In recent years, organic electrochemical transistors (OECTs) have emerged as a promising tool to add to current analytical methods due to their high-amplification capacities, robust analytical performance, and versatility. The present work proposes a compact multi-analyte transistor array with outstanding analytical performance. The ion-selective organic electrochemical transistors (IS-OECTs) were developed by combining the thick-film technology with the optimum ion-selective membrane, resulting in highly sensitive and selective IS-OECTs. The system has then been simplified using only a power supply for each OECT and a single gate electrode. To prove these advantages, the IS-OECT array of sensors has been combined with multivariate models to simultaneously detect and quantify sodium, potassium and ammonium ions in human saliva. The results obtained have been validated against reference techniques, showing promising results and confirming the usefulness of the newly developed sensing array.