Date of Completion

2023

Document Type

Honors College Thesis

Department

Chemistry

Thesis Type

College of Arts and Science Honors, Honors College

First Advisor

Yangguang Ou, Ph.D.

Keywords

electrochemistry, fast-scan cyclic voltammetry, biosensor, theta oscillations, epilepsy, learning and memory

Abstract

Abnormal release of acetylcholine (ACh) in the brain has been implicated in major neurological disorders like epilepsy, however little technology has been developed to allow for real-time, rapid, and spatially precise in vivo measurements of this neurotransmitter. We optimized carbon fiber microelectrodes (CFMs) for such measurements using surface adsorption of acetylcholinesterase (AChE) and choline oxidase (ChO) followed by electrochemical deposition of Nafion. Sensitivity, stability, and selectivity were characterized via flow injection analysis and in vivo measurements were taken in rat hippocampi, all using fast-scan cyclic voltammetry (FSCV). We established a 1:10 ratio of AChE:ChO to be the most optimal with a highly linear calibration curve (r2=0.986) as well as a limit of detection of 0.814 mM and a limit of quantification of 2.711 mM. The electrodes demonstrated high selectivity against dopamine and ascorbic acid (p<0.0001) and remained stable throughout multiple injections over the course of several hours (r2=0.053). Significant in vivo events were recorded and quantified. These results suggest that FSCV on CFMs hold promise for continuous and spatiotemporally sensitive measurements of ACh in vivo. Further optimization and in vivo testing may broaden the applications of this ACh CFM for eventual use in elucidating the treatment of other ACh-related diseases like Parkinson’s and Alzheimer’s.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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