A Paper-Based Ion-Selective Organic Electrochemical Transistor for Highly Sensitive Determination of Creatinine and Potassium

Abstract

A novel paper-based ion-selective organic electrochemical transistor (IS-OECT) for the detection of potassium and creatinine is presented. First, ion-selective membranes are cast onto thick-film transistor channels to create highly sensitive and selective ion sensors. Since optimum performance is obtained at 0 V gate voltage, several sensors can be used in parallel with a single gate connected to a common grounded source electrode. Then, to further demonstrate the detection capabilities, the IS-OECTs were integrated with a purposely designed differential amplifier. This allows the conversion of current signals into a voltage output, facilitating comparison with potentiometric systems and the use of low-cost commercial data acquisition platforms. The evaluation of the performance in artificial serum is performed in clinically relevant ranges, which comprise 2.4–5.75 mM for potassium and 30–140 μM for creatinine. These results highlight the potential of the IS-OECT framework as a cost-effective, portable, and reliable solution for point-of-care diagnostics.