Session Overview |
Tuesday, May 28 |
08:30 |
Introduction
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08:45 |
Computational fluorescence lifetime imaging microscopy
* Liang Gao, UCLA, United States of America Fluorescence lifetime imaging microscopy (FLIM) measures fluorescence lifetimes of fluorescent probes to investigate molecular interactions. However, conventional FLIM systems often requires extensive scanning that is time-consuming. To address this challenge, we developed a novel computational imaging technique called light field tomographic FLIM (LIFT-FLIM). Our approach acquires volumetric fluorescence lifetime images in a highly data-efficient manner, significantly reducing the number of scanning steps. We demonstrated LIFT-FLIM using a single-photon avalanche diode array on various biological systems. Additionally, we expanded to spectral FLIM and demonstrated high-content multiplexed imaging of lung organoids. LIFT-FLIM can open new avenues in the biomedical research. |
09:10 |
Augmenting Tumour Ablation with Radiation-activated Photodynamic Therapy (radioPDT) for Precision-guided Radiotherapy
* Deepak Dinakaran, , Canada Abul Kalam Azad, University of Alberta, Canada Hua Chen, University of Alberta, Canada Houston Cole, University of Texas Arlington, United States of America Colin Cameron, University of Texas Arlington, United States of America Lothar Lilge, University Health Network, Canada John Lewis, University of Alberta, United States of America Sherri McFarland, University of Texas Arlington, United States of America Ronald Moore, University of Alberta, Canada Traditional external light-based Photodynamic Therapy (PDT)’s application is limited to the surface and minimal thickness tumors because of the inefficiency of light in penetrating deep-seated tumors. To address this, the emerging field of radiation-activated PDT (radioPDT) uses X-rays to trigger photosensitizer-containing nanoparticles (NPs). We developed a biocompatible radioPDT nanoparticle with pegylated poly-lactic-co-glycolic (PEG-PLGA) encapsulating LaF3:Ce3+ nanoscintillators (NSCs) along with a photosensitizers such as protoporphyrin IX (PPIX/radioPDT) or high quantum efficiency ruthenium-complexed photosensitizer (Ru/radioPDT). These nanoparticles exhibited minimal cell toxicity until activated by radiation to induce significant cancer cell kill over radiation alone. PPIX/radioPDT was able to significantly increase cancer cell cytotoxicity by 2-fold over radiation alone given in a single fraction of 2 to 8 Gy. Dependence on oxygen concentration was seen for radioPDT effects, with a half-maximal cytotoxicity effect occurring at ~ 5% oxygen. A higher therapeutic effect was also seen in human prostate cancer mouse xenografts treated with radioPDT versus 6 Gy of RT alone - inhibiting local tumor progression, doubling median overall survival (56 days versus 36 days, p=0.01), and rendering 25% of mice with no evidence of disease at 60 days post-RT. In comparison to protoporphyrin IX-mediated radioPDT (PPIX/radioPDT), Ru/radioPDT showed higher capacity for singlet oxygen generation, however, maintaining comparable cytotoxic effect on PC3 cells. Taken together, augmenting radiation through radioPDT may prove to be a promising strategy in achieving tumour ablation in humans. |
09:35 |
Quantitative Super-Resolution Imaging of Molecular Force in Cell Adhesion
* Isaac Li, The University of British Columbia, Canada DNA-based molecular tension probes have revolutionized the imaging of mechanical events in live cells. However, the precise quantification of force at super-resolution has posed significant challenges. We introduce Quantitative Tension PAINT to measure the molecular force magnitude with super-resolution accuracy. Leveraging the force-dependent dissociation kinetics of DNA oligonucleotides under tension, we effectively encoded tension on individual molecules via their binding kinetics. This enabled a quantitative analysis of these kinetics, providing a detailed reconstruction of the force magnitudes acting on each tension probe. |
09:50 |
Double-clad fiber Photon Absorption Remote Sensing probe for high resolution label-free imaging
* Jenna Veugen, University of Waterloo, Canada James Alexander Tummon Simmons, University of Waterloo, Canada Parsin Haji Reza, University of Waterloo, Canada This work focuses on the development of a fiber-based Photon Absorption Remote Sensing (PARS) imaging probe for label-free imaging unconstrained to a benchtop setup. This system utilizes, for the first time to our knowledge, a double clad fiber paired with a dual green PARS system to obtain high resolution non-contact images. Compared to previous PARS fiber models, significant improvements in signal-to-noise ratio and contrast demonstrate the potential towards a PARS endoscopic system for in situ optical biopsies. |
10:05 |
Multi-Wavelength Photon Absorption Remote Sensing: Non-Contact Label-Free Functional Vascular Imaging
* Sarah J. Werezak, University of Waterloo, Canada James Alexander Tummon Simmons, University of Waterloo Parsin Haji Reza, University of Waterloo Functional vascular metrics, such as oxygen saturation (SO2), are highly valuable for diagnosis and treatment in oncology and ophthalmology. This work demonstrates the first in vivo multi-wavelength Photon Absorption Remotes Sensing (PARS) system. Implementing two excitation wavelengths leverages the varying absorption spectra for oxy- and deoxy-hemoglobin, laying the groundwork for SO2 measurement. New system developments for SO2 measurement includes independent excitation paths, pulse-specific power compensation, and radiative contrast to further work towards a PARS oximeter that achieves ISO accuracy standards. |