Dr. Alex Zestos
American University – Department of Chemistry
Friday, February 12, 2021
HOST: Dr. Chengpeng Chen
Multiplexing Neurochemical Detection Using Fast Scan Cyclic Voltammetry
The brain is by far the most heterogeneous organ, and it is critically important to monitor various brain regions simultaneously in order to understand complex pharmacological, drug, and behavioral states. Therefore, it is critically important to make high temporal resolution neurochemical measurements to study the phasic firing of neurons in several brain regions concurrently. Fast scan cyclic voltammetry (FSCV) and carbon-fiber microelectrodes (CFMEs) have been utilized used to detect several important neurochemicals in vivo. Polymer coatings and waveform modifications have been used to increase sensitivity, selectivity, and temporal resolution. Specific applications discussed will be ex vivo in zebrafish retina, brain slices, and for the detection of DNA and RNA.
FSCV allows for high temporal measurements (< 100 msec) of neurotransmitter levels. Some of the many applications of this technique could be measuring neurochemical changes during epileptic seizures with simultaneous EEG measurements in rodents, drug abuse studies, measuring robust dopamine increases during deep brain stimulation in Parkinsonian models, and possibly many others.
This work will also discuss the development of multielectrode arrays (MEAs) for neurotransmitter detection with fast scan cyclic voltammetry in multiple brain regions simultaneously. Parylene and silicon insulated carbon fiber microelectrode arrays were shown to be able to measure neurochemicals in multiple brain regions simultaneously when coupled with multichannel potentiostats. Moreover, we have utilized techniques such as plasma enhanced chemical vapor deposition (PECVD) to deposit conductive carbon nanospikes onto the surface of existing metal multielectrode arrays to give them dual functionality as neurotransmitter sensors with FSCV in addition to being used primarily for electrical stimulation and recording. Other assays have shown the utility of electrodepositing carbon nanotubes and polymers such as PEDOT to coat metal arrays with carbon to give them dual sensing capabilities.