Electrolyte-Gated Ionic Transistor for Highly Sensitive and Selective Iontronic Sensing.

Iontronic sensors based on confined space have garnered significant attention due to their promising applications, ranging from single-cell analysis to studies. However, their limited sensitivity has constrained their effectiveness in studying molecular information during physiological and pathological processes. Here, we demonstrate an electrolyte-gated ionic transistor (EGIT) by integrating the confined ion transport behavior in a double-barreled micropipet with an electrolyte-gated transistor configuration, achieving highly sensitive and selective sensing. Our EGIT operates at a gate voltage of less than 1 V and can amplify ion current variations by up to 2 orders of magnitude. Both experimental methods and finite element simulations reveal that signal amplification stems from the intensified electric field. Thanks to the easily modified inner surface of the micropipet and the transistor configuration, we develop a highly sensitive and selective iontronic sensing platform for neurochemicals such as ATP, dopamine, and serotonin. More importantly, by utilizing this iontronic sensor, we successfully achieve the detection of trace ATP in rat striatum microdialysate. This study not only expands the scope of transistor technologies but also introduces a novel approach for constructing highly sensitive iontronic sensors, which hold potential applications in biochemical sensing, health monitoring, and disease diagnosis.