Selective Ion Sensing Organic Electrochemical Transistors Suitable for Blood Analysis

Abstract

AbstractOrganic electrochemical transistors (OECTs) have gained considerable attention due to their ability to simultaneously transduce and amplify ion‐based biological signals into electronic signals in bioelectronics. In this study, functionalized OECTs capable of detecting specific ion concentrations in aqueous solution and blood serum are investigated and described. Sodium, the most concentrated cation in the human body, is chosen as the target analyte due to its critical role in maintaining normal bodily functions such as blood pressure, nerve and muscle function, and fluid balance. These sodium ion sensors work at low source‐drain voltage, Vds = 0.4 V and gate voltage, Vg = 0 V, and demonstrate a high sensitivity of 126 μA dec−1 and a high selectivity over different cations. Furthermore, the OECT biosensors are employed to determine sodium concentration in more complex environments and demonstrated a log‐linear response within the physiological range of sodium in blood serum, ranging from 100 to 160 mm. In the final part of the study, the transistor‐based sensor is fabricated in a small‐footprint neural probe configuration and its sensing capability is investigated. These characteristics open up new opportunities for applications in wearable and implantable electronics.