06/23/2023
By Kwok Fan Chow

The Kennedy College of Science, Department of Chemistry, invites you to attend a Ph.D. Dissertation defense by Keshani Pattiya Arachchillage entitled “Single-Molecule RNA Electrical Detection for Applications in Cancer and COVID-19.”

Degree: Doctoral
Date: Friday, July 7, 2023
Time: 10:30 a.m.
Location: Olney, Room 518

Committee Chair: Prof. Juan Artes Vivancos, Department of Chemistry, University of Massachusetts Lowell

Committee Members:

  • Prof. Jin Xu, Department of Chemistry, University of Massachusetts Lowell
  • Prof. Kwok-Fan Chow, Department of Chemistry, University of Massachusetts Lowell
  • Prof. Pengyuan Liu, Department of Chemistry, University of Massachusetts Lowell

Abstract:
The COVID-19 pandemic and the rise of healthcare issues like cancer highlight the imperative for innovative, efficient, and highly sensitive early disease detection methods based on liquid biopsy biomarker analysis. These advanced detection methods have the potential to significantly reduce mortality rates by enabling the timely identification and differentiation of disease variants, thereby facilitating targeted and effective treatment strategies. This thesis demonstrates the Scanning Tunneling Microscopic (STM)-assisted break junction method to detect coronavirus biomarker sequences, ranging from the whole human coronavirus family to SARS-CoV-2 sub-variants level. Our findings demonstrate the ability to distinguish between different COVID-19 variants using electrical conductance signals, in line with recent theoretical proposals. Furthermore, we propose an approach to identify new variants by analyzing electrical signatures from multiple sequences.

In addition, we demonstrate the electrical detection of RNA cancer biomarkers, specifically the KRAS mutants G12C and G12V, as a proof-of-concept for a single-molecule electrical biosensor aimed at cancer screening applications. Our study reveals that single-molecule electrical conductance exhibits high sensitivity to nucleic acid sequences, enabling discrimination between mutants and wild-type KRAS sequences differing by only one base. Notably, this biosensor displayed exceptional sensitivity, detecting individual molecules with a strong signal-to-noise ratio. To investigate the sensor's performance furthermore, we employ electrochemistry methods and compare them with single-molecule approaches in biosensing, providing valuable insights into their respective strengths, limitations, and overall effectiveness. Overall, these results lay the foundation for the future development of miniaturized nanobiosensors with the potential to revolutionize disease detection, including cancer, COVID-19, and environmental monitoring.

All interested students and faculty members are invited to attend.