Authors: Samantha K. Smith
Source: NCSU Libraries Repository (North Carolina State University Libraries) (article, 2018-03-16)
Field: Chemistry — Electrochemistry

Advancing Microbiosensor Development for the Real-Time Electrochemical Detection of Multiple Analytes in Rat Brain Tissue. Advancing Microbiosensor Development for the Real-Time Electrochemical Detection of Multiple Analytes in Rat Brain Tissue.(Under the direction of Dr. Leslie A. Sombers)Actions of opiates, alcohol, and major stimulants, such as cocaine, converge on the dopaminergic systems in the brain to modify synaptic activity and behavior.The neurotransmitter dopamine is critically involved in cognition, sensorimotor integration, and modulation of motivated behaviors.However, little is known about the energetic substrates that fuel these circuits, or how molecules such as glucose and lactate are altered upon neuronal activation and exposure to drugs of abuse.The brain utilizes glucose and lactate to fuel metabolic processes that control how we think, feel and behave.However, evidence is lacking to describe rapid changes in energy availability in discrete brain regions.The electrochemical approach, fast-scan cyclic voltammetry (FSCV), is well suited for monitoring neurochemical signaling because of the subsecond time resolution and selectivity.Recent developments in our research group have coupled FSCV to carbon-fiber microbiosensors to enable the measurement of glucose and lactate dynamics in brain tissue.This was a critical development as we can now monitor real-time fluctuations of energy availability in the extracellular space on the time scale of neuronal activation.The work presented herein describes the development, characterization and utilization of microbiosensors for simultaneous detection of glucose and lactate in rat brain tissue.Investigations of enzyme attachment strategies for optimal subsecond detection of nonelectroactive chemicals were completed.A hydrogel entrapment strategy was found to be the most stable and reproducible method for enzyme placement on a microelectrode sensing surface.An optimized voltammetric waveform was developed for simultaneous detection of glucose and dopamine at a single recording site in real-time.These unprecedented data revealed an increase in energy availability in response to metabolic demand after neuronal activation via electrical or pharmacological stimulation.Additionally, a microbiosensor was developed for sensitive, selective and stable detection of subsecond lactate dynamics.This novel microbiosenor was coupled with a glucose sensor to simultaneously quantify these species and dopamine at one location utilizing FSCV in the rat striatum.Data collected revealed diverse temporal dynamics of these molecules in response to neuronal activation.Collectively, this dissertation describes the development, characterization, and application of important new tools to advance our fundamental understanding of brain energy availability, and to elucidate how key energetic substrates respond to neuronal activation.It has been used to demonstrate that glucose, lactate and dopamine are collectively implicated in brain function, and Analyte ; Brain tissue ; Chemistry ; Chromatography ; Computer science ; Neuroscience ; Biomedical engineering ; Medicine ; Biology Electrochemical Analysis and Applications