In Situ Electrically Resettable Field-Effect Transistor Biosensors for Continuous and Multiplexed Neurotransmitter Detection.

Accurate, real-time detection of neurotransmitters is crucial for elucidating the mechanisms of brain function and tracking the progression of neurological diseases. Biosensors usually face poor reusability induced by difficulties in probe-target separation, hindering their application for continuous monitoring. In this work, a semiconducting carbon nanotube (CNT) film field-effect transistor (FET) biosensor is developed using pH-sensitive aptamers as probes to capture targets. Through tuning the potential of on-chip palladium electrodes, the biosensor facilitates in situ pH modulation and recovery of the sensor interface, which enables an electrically resettable biosensor. The fabricated sensor demonstrates exceptional sensitivity (with femtomolar-level detection limits), high selectivity (specific responses are 20 times stronger than non-specific ones), and excellent reusability (over ten reuse cycles). Furthermore, in vitro detection demonstrates that the biosensor arrays, incorporating regional modifications and pH-sensitive probes, enable the simultaneous detection of several neurotransmitters, including dopamine, serotonin, histamine, and glutamate in complex biological samples. The combination of microfluidic techniques further lowers non-specific adsorption and cross-reactivity, ensuring reliable, repeatable real-time detection. The resettable CNT FET biosensor array holds significant promise for advancing the monitoring of neurotransmitter dynamics, serving as a powerful tool for the early diagnosis and management of neurological disorders.