Distinguishing Nucleotides Using Electrochemical Impedance Spectroscopy
International Conference on Epigenetics and Bioengineering
Wednesday, December 13, 2017 - 4:45pm to 6:30pm
Electrochemical impedance spectroscopy applies an alternating potential to sense the impedance to the resulting current flow. The resistance associated with the transfer of charge can be determined through analysis, and this resistance is proportional to the amount of DNA absorbed on the gold surface rather than change of the solution resistance itself. For this work, the bare gold electrode was polished then soaked for 5 minutes in nucleic acid bases dissolved in UHP water. To investigate the reproducibility of our data, triplicates were conducted for adenine, cytosine, and guanine. We also investigated the differences in measurement of both static cell and flow cell methods. Finally, we also determined the surface resistance change when the gold electrode is exposed to individual bases and 17-base repeat oligonucleotides in a flow cell.
Currently, when statistically comparing the charge transfer resistance for the flow cell, each nucleotide base can be individually distinguished from the control. However, for longer oligonucleotide chains, adenine cannot be distinguished from the control. In both of these cases, adenine produced the smallest charge transfer resistance and guanine had the largest standard deviation between trials. Several characteristics of purine rings may contribute to these unexpected results, the most likely of which is base stacking due to the use of UHP water as the solvent. We will present our progress on reproducibility and accuracy of measurements, and our future work to expand this into a senior honors thesis.
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