When
Monday, March 30, 2026, at 12:00 p.m.
Location: Keating 103 | Zoom link
Hosts: Swarna Ganesh and Kellen Chen
Romi Castillo
PhD Candidate, Tardiff Lab
"A Novel TR-F Based High Throughput Screen to Identify Small Molecules that Modulate Diastolic Performance"
Abstract: Hypertrophic cardiomyopathy is a genetic cardiac disorder of the sarcomere that affects approximately 1/250-1/500 individuals globally. One of the earliest manifestations of the disease is impaired myocardial relaxation. This is an observable trait of preclinical HCM patients where impaired relaxation can be identified prior to the development of left ventricular hypertrophy. Here we develop a time-resolved fluorescence-based high throughput screening platform to identify small molecules that can enhance myocardial relaxation. Our optimized screening system yielded a hit rate of 3% and identified 360 small molecules that bind to the cardiac thin filament and produce a structural change in the N-terminus of cardiac troponin I, a region of the thin filament that is known to regulate cardiac relaxation. We proceeded with these small molecules for secondary screening and found that many alter the rate of thin filament deactivation. The small molecules that accelerated thin filament deactivation were moved forward with for tertiary screening using murine myofibril ATP-ase. Small molecules from this screen restored ATP-ase rates in myofibrils isolated from our HCM disease model. Future work will include scaling up the testing of the small molecules in more complex systems such as cardiomyocytes or the whole organ level. Altogether, this work provides a novel screening method to identify small molecules that can modulate diastolic performance with the potential to treat HCM or diseases of diastolic dysfunction more broadly.
Duy Mac
PhD Candidate, Su Lab
"Advancing Ultra-Sensitive Biosensing and Fast Nanoscale Imaging with Frequency-Locked Microtoroid Resonator Systems"
Abstract: The detection of single biomolecules is critical across biology, medicine, materials science and fundamental research, with broad applications in disease diagnostics, therapeutics, drug discovery and nanotechnology. Whispering gallery mode (WGM) microtoroid resonators constitute a state-of-the-art biosensing platform, leveraging ultra-high-quality optical resonances to enable label-free detection of binding events with exceptional sensitivity, including single-molecule and nanoscale detection.
In this talk, I will present three projects that highlight the capabilities and emerging directions of this platform. First, using the Frequency-Locked Optical Whispering Evanescent Resonator (FLOWER) system, we evaluate platelet factor 4 (PF4) as a potential biomarker for Lyme disease by quantifying PF4 concentrations in human serum samples from both disease and control groups. Second, by functionalizing the microtoroid with an artificial lipid bilayer, we immobilize the G protein–coupled receptor (GPCR) TAS2R5 on the resonator surface, enabling binding assays to measure the affinity of various agonists.
Finally, building on our prior demonstrations of photothermal imaging of nanoscale objects down to 5 nm quantum dots, we implement a hybrid locking approach with free-space coupling to image a single 100 nm gold nanosphere. This free-space architecture removes the reliance on fragile fiber tapers and represents a key step toward translating WGM-based photothermal sensing into aqueous and biologically relevant environments.