Jason Raymond, who was a member of the Ultrasonics group from 2002-2009, returned to give a colloquium talk on his work on echogenic liposomes. Jason is currently finishing up a stint at the University of Cincinnati where he got his PhD in Biomedical Engineering.
Lipid-shelled Ultrasound Contrast Agents for Imaging and Therapy: Stable and Unstable Dynamics
Lipid-shelled ultrasound contrast agents known as “echogenic liposomes” are nanoparticle theragnostic agents being developed to target and treat cardiovascular disease. This talk will present recent results using an ultra-high-speed optical imaging approach to investigate the acoustic response of these agents. The investigations utilize an ultra high-speed imaging system (“Brandaris 128”, Rotterdam, the Netherlands) which was developed for imaging physical phenomena such as ultrasound-microbubble interaction at up to 20 million frames per second. Results of two studies using this unique imaging facility will be presented. In the first study, we demonstrate a method to estimate the acousto-mechanical properties based on the impulse response. In the second study, we investigate the response to multiple-cycle acoustic pulses, which result in loss of gas from individual particles. These studies demonstrate that acoustically-active or “echogenic” liposomes can be considered a theragnostic agent, with both stable and unstable dynamics that can be exploited using different ultrasound parameter regimes.