Daily Archives: January 31, 2014

Beneficial Bubbles: Ultrasound-Mediated Drug Delivery

date January 31, 2014
comments no comments.

Friday, January 31, 2014 12:00 p.m. ETC 2.136

Professor Christy K. Holland
Department of Internal Medicine and Biomedical Engineering Program
University of Cincinnati
http://www.ultrasound.uc.edu/people.html

Ultrasound is under development as a potent promoter of beneficial bioeffects for the treatment of cardiovascular disease.  These effects can be mediated by mechanical oscillations of circulating microbubbles, referred to as ultrasound contrast agents, which can also encapsulate and shield a therapeutic agent in the bloodstream.  Oscillating microbubbles can create stresses directly on nearby tissue or induce fluid motion that affect drug penetration into vascular tissue, lyse thrombi, or direct drugs and bioactive gases to optimal locations for delivery.  Ultrasound-triggered release of nitric oxide from echogenic liposomes induces potent vasorelaxation in porcine carotid arteries in an ex vivo system.  Recent in vitro and ex vivo data from a variety of clot and vascular models will be discussed.

This acoustics seminar is offered courtesy of the Chevron Centennial Seminar Series in the Department of Mechanical Engineering, and pizza will be served.

Bubble Pulsation and Translation Near a Soft Tissue Interface

date January 31, 2014
comments no comments.

Friday, January 31, 2014 4:00 p.m. ETC 4.150

Daniel R. Tengelsen
Department of Mechanical Engineering and Applied Research Laboratories
The University of Texas at Austin
https://www.arlut.utexas.edu

A Lagrangian formalism used previously to calculate the pulsation of a spherical bubble immersed in liquid and adjacent to a viscoelastic layer is extended here to include bubble translation. Previous models and experiments have shown that the direction of bubble translation near a viscoelastic layer is correlated with the direction of a liquid jet often produced by the bubble during collapse. The liquid jet is an important feature in the interaction between bubbles and neighboring surfaces. In this presentation we describe how to model the pulsation and translation of a spherical bubble near a liquid-solid interface, with emphasis on soft tissue, in order to determine the direction of bubble translation for a broad spectrum of material properties for both the liquid and viscoelastic medium, and for various distances between the bubble and the interface. The force on the bubble due to the presence of the liquid-solid interface is calculated using a Green’s function that takes into account elastic waves, viscosity in the layer, and the viscous boundary layer in the liquid adjacent to the interface.