Date of Award


Degree Name

Master of Science



First Advisor

Shamsi, Mohtashim


CAG is a trinucleotide repeat that is associated with diseases such as Huntington’s disease and at least 8 other neurodegenerative disease. There is a need to continuously find and improve ways to detect these diseases early. This study details the approaches applied in the study of the application of CTG-6 in detecting CAG of different repeat lengths. Based on Au-S chemistry, a gold working electrode was fabricated from gold plated silicon wafers. The working electrode was modified using thiol modified CTG-6 oligonucleotide as the probe, and 6-mercapto-1-hexanol to manage non-specific adsorption on the surface. For the biorecognition layer, the probe concentration was optimized to 20 nM. The optimized biorecognition layer was then applied to the detection of CAG-6 based on the principle of nucleic acid hybridization. Electrochemical observations were noted using a Ag/AgCl electrode as the reference electrode and a Pt counter electrode. At each target concentration, the charge transfer resistance (RCT) was recorded. From the target concentrations presented in this study, a maximum RCT of 15.3 ± 0.9 kΩ was observed at 100 pM CAG-6. For further optimization and future studies, it is recommended that 100 pM CAG-6 is used.




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