In-Vitro Real-Time Coupled Electrophysiological and Electrochemical Signals Detection with Glassy Carbon Microelectrodes

Abstract

The ability to carry out coupled and simultaneous electrical and electrochemical signals detection in the context of central and peripheral nervous systems has been of major research interest for sometimes now. This real-time capability could significantly help in developing more complete insight and understanding of the underlying mechanism of the interplay between electrical and neurotransmitter signals in neural communications at synapses, particularly in diseased states. Further, with increasing clinical interest in the use of electrical stimulation as therapeutic platform for variety of disease states from spinal cord injury to Parkinson's disease and essential tremor, there is pressing need for understanding the actual mechanism of its efficacy. In this study, therefore, we present an enabling platform that consists of a novel polymeric probe supported on a flexible substrate with microelectrode array specifically targeting simultaneous detection of neurotransmitters and electrophysiological signals. This probe consists of an array of patternable glassy carbon (GC) microelectrodes which have a superior electrochemical performance due to their wide electrochemical window and surface attachment chemistry tailorability along with excellent and stable conductivity. In this study, we report that these microelectrodes can detect – in real time – serotonin, a key neurotransmitter involved in mood and sleep regulations, in in-vitro environment within 25 nM - 1 μM concentration range with resolution of 25 nM while simultaneously recording ECoG (electrocorticography) electrical signals. The probes are also capable of stimulating at a current density of 2.5 A/cm2 (360 μA) and wide voltage range of at least −0.6 V to +1.2 V with remarkable stability.