Simultaneous Electrochemical Detection of Multiple Neurotransmitters

Neurotransmitters are chemical signaling molecules that play a crucial role in the formation and function of human physiological and psychological processes. Monitoring dynamic changes in neurotransmitters can enhance our comprehension of the underlying brain chemistry including mechanisms of neurotransmission, neurotoxicity, and neurological disorders. Electrochemical biosensors provide an accessible, cost-efficient, and temporally sensitive detection platform that has been used for continuous monitoring of multiple analytes simultaneously. In this work, four enzymatic neurotransmitter sensors were adapted and characterized for use with a microfluidic, eight-channel screen-printed electrode array. We show sensitive, selective, and stable amperometric detection of glutamate, acetylcholine, adenosine, and dopamine. Detection and quantitation limits for all four neurotransmitter sensors were found to be in the physiological range in certain brain regions for neurochemical investigation. Additionally, the electrodeposition of m-phenylenediamine significantly mitigated electrochemical interference from ascorbic acid and dopamine—both prevalent in the neuronal systems. The stability of each of these enzyme sensors is reported following ten hours of continuous use. This microfluidic, multi-neurotransmitter screen-printed electrode can be integrated into biological systems—such as organ-on-chips—for monitoring complex neurotransmission.