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Topic

Temperature-Controlled Nanoaperture Optical Trapping

Department of Electrical and Computer Engineering

Date & location

• Friday, September 15, 2025

• 10:30 A.M.

• Virtual Defence

Reviewers

Supervisory Committee

• Dr. Reuven Gordon, Department of Electrical and Computer Engineering, University of Victoria (Supervisor)

• Dr. Levi Smith, Department of Electrical and Computer Engineering, UVic (Member) 

External Examiner

• Dr. Kyle Duncan, Department of Chemistry, Vancouver Island University 

Chair of Oral Examination

• Dr. Abdul Vahabpour Roudsari, School of Health Information Science, UVic

   

Abstract

Nanoaperture optical trapping (NOT) enables the capture of single proteins to detect of their conformational dynamics without labeling or tethering, thus preserving their structure. Protein folding is highly sensitive to environmental conditions, making the investigation of thermodynamic parameters a robust method for probing conformational stability. While previous studies have employed laser-induced heating to modulate the local temperature, such methods are limited in accessing broader temperature ranges. In this work, the low-temperature dynamics of individual Bovine Serum Albumin (BSA) are investigated using a custom-built temperature-controlled stage. The transitions between the normal (N) and fast (F) conformational states of BSA were uncovered. Notably, the N form exhibited a maximum occupancy at 21 ±1◦C, which was interpreted as the point of maximal thermodynamic stability for the compact N state relative to the F state. This approach enabled the extraction of single-molecule thermodynamic parameters without requiring modification to the protein’s native structure, providing a multifaceted NOT method for broad applications.