ME Seminar: Lung Surfactant Coated Microbubbles and Nanodrops

November 24, 2:00pm - 3:30pm
Mānoa Campus, Holmes Hall 287

Lipid-coated, perfluorocarbon-filled microbubbles have been developed as ultrasound contrast agents for medical imaging and as drug delivery vehicles with focused ultrasound, for example in blood-brain barrier modulation to increase transvascular solute transport to/from the brain. When cooled and pressurized below the fluorocarbon boiling point, the core can be condensed into a liquid that remains superheated when brought back to physiological conditions due to the energy barrier for homogeneous nucleation. Thus, microbubbles can be condensed into superheated nanodrops which, when activated by ultrasound, can be vaporized in situ back into highly echogenic microbubbles. Novel microbubbles and nanodrops are being engineered for improved accuracy and precision in medical imaging and therapy. The choice of lipid has a tremendous impact on the interfacial properties of the microbubble or nanodrop. For example, longer acyl chains can be used to decrease gas permeability and increase surface viscoelasticity, thereby creating more stable microbubbles and nanodrops with greater shell stiffness during acoustic forcing. One interesting material that our lab has been investigating recently is lung surfactant, specifically the lung surfactant replacement therapy formulation beractant (Survanta), which is a bovine extract commonly employed to treat neonates with respiratory distress. Survanta was shown to stiffen microbubble shells compared to the main lipid component, DPPC, providing longer circulation persistence in vivo. Additionally, Survanta displays a melting transition during slow bubble expansion which is not exhibited in pure DPPC shells. Thus, Survanta shows provides greater stability of post-vaporization bubbles following acoustic vaporization of nanodrops. Overall, lung surfactant shows interesting properties that may be exploited for future biomedical applications in imaging and therapy. Also available on Zoom: https://hawaii.zoom.us/j/84857991192 Meeting ID: 848 5799 1192 Passcode: 4NEXLr


Event Sponsor
Mechanical Engineering, Mānoa Campus

More Information
Samantha Kawamoto, 8089567167, meoffice@hawaii.edu

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