Date Approved


Graduate Degree Type


Degree Name

Cell and Molecular Biology (M.S.)

Degree Program

Cell and Molecular Biology

First Advisor

Dr. Eric Ramsson

Second Advisor

Dr. Sok Kean Khoo

Third Advisor

Dr. Scott Thorgaard

Fourth Advisor

Dr. Andrew Korich

Academic Year



Dysregulation of dopamine release is a pathological effect of common neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Fast scan cyclic voltammetry (FSCV) has been used as an analytical tool to investigate the role of dopamine in these diseases, and in relation to drug addiction and reward behavior. Methods to improve the sensitivity of FSCV have involved modifying the surface of the carbon electrodes used for dopamine detection, altering the potential waveform, and changing the structure of the carbon sensor. Here, the amino acid tryptophan was investigated as a potential surface modification for increased dopamine detection. This study serves as an in vitro proof of concept for tryptophan modified electrodes for FSCV detection of dopamine. The mechanism of tryptophan surface modification was also investigated in this study. Tryptophan covalently binds to the carbon surface at the 3’ nitrogen in the indole R’ group, which is a stable bond as demonstrated through extensive cycling of the electrode. The electrodes demonstrated an average 15 fold increase in sensitivity for dopamine based on current density. In addition, tryptophan modified electrodes were highly selective for dopamine over the interfering biomolecule ascorbic acid. Moving forward, an in vivo proof of concept for tryptophan modified electrodes is necessary before dopamine detection can occur in clinical applications.