Grant: CIHR-ICRH Travel Awards - General pool

Ultrasound (US) is a non-invasive, cost effective, non-toxic and rapid modality to monitor blood flow and detection of pathologies in cardiovascular ultrasound ranging mm sized vessels down to micro-vasculature. US has potential for non-invasive clot lysis. US contrast agents (microbubbles, nanobubbles and nanodroplets) are fundamental to these applications; however, their response to ultrasound exposure parameters is complex and heavily depends on their size and shell. Conventional contrast agents have broad size distribution and only a subpopulation of these agents are responsive for a given US exposure parameters. Moreover, in applications like clot lysis, the off target agents can become resonant, shielding the target from receiving US energy and damaging the healthy tissue. Therefore, understanding their behavior and narrowing the size of these agents is crucial for enhancing the contrast in images and increasing the treatment efficacy and precision. In the two accepted works, I present a novel method to manufacture narrow size microbubbles and nanodroplets with high yield. In the oral presentation, I provide the first time quantitative measurements of the strong influence of the liquid ions on the microbubbles shell and US response. This propels our understanding of the interaction of these agents with the blood ions and have applications in enhancing and controlling their oscillations in blood. In the second work, I manufactured size ioslated nanodroplets between 100-200nm. To our best knowledge this is the first study that reports controlled concentration of C4F10 core nanodroplets. These agents can propel through small pores under ultrasound exposure with improved performance on clot lysis. Their acoustic behavior was characterized and compared to parent microbubbles for the first time, providing the foundation for the pre-clinical exploration of these agents in therapeutic US applications including clot lysis and targeted tumor vascular disruption.