YPJoin us for our Special Seminar as Dr. Yoonjee Park, Ph.D., Postdoctoral Research Associate, Research Labratory of Electronics, MIT, Cambridge, MA, presents her lecture on “Stable Biomedical Colloids for Imaging Contrast Agents and Drug Delivery Systems.” The presentation will take place on Monday, October 20th, from 1:30-2:15p in MEB 3147. All are welcome to attend.

Biography: Yoonjee Park is currently a postdoctoral associate in Research Laboratory of Electronics at Massachusetts Institute of Technology. She received her Ph.D. in Chemical Engineering from Purdue University in 2010, where she developed stable aqueous lipid formulations with low surface tension behavior at physiological conditions. She received her B.S. in Chemical Engineering from Seoul National University in 2006. Her current research interests are quantitative and precise molecular imaging and non-invasive therapeutics with minimal side effects by developing stable and effective imaging contrast agents and drug delivery systems.

Abstract: Colloidal systems have been recently studied extensively and intensively in the biomedical area for imaging contrast agents and drug delivery carriers. In this talk, I will discuss “biomedical colloids” that I have developed, including (i) lung surfactant vesicles that can be used for treating acute respiratory distress syndrome at the air/water interface, and (ii) tunable microbubbles for ultrasound imaging. Lastly, I would like to mention about my recent study, direct observation of enhanced drug delivery via microbubble cavitation of blood vessels on-a-chip.

In human lungs, lung surfactant at the interface of air/hypophase stabilizes the lung alveoli against collapse or overexpansion during breathing. The mechanism involves the lowering of the surface tension of alveolar lining layer. With certain lung alveolar diseases, blood serum proteins are secreted into the alveolar lining layer and the proteins inhibit the surfactant interfacial function. I have developed a synthetic lung surfactant formulation using PEGylated lipid, which is effective for achieving both colloidal dispersion stability and favorable dynamic surface tension behavior with albumin.

A microbubbles, a micron-sized bubble (<8 μm in diameter) with a gas core, is suitable as an ultrasound contrast agent providing a detectable echogenic signal in vivo. However, challenges remain in terms of stability of the micorbubbles against destruction from aggregation and gas dissolution for improving blood circulation times and reducing clogging of small blood vessels. By using a photopolymerizable diacetylene lipid as a component in a microbubble shell matrix, the surface properties such as elasticity or resistivity against gas dissolution has been tuned.

Recently, many studies have reported the effect of microbubbles behavior under ultrasound on perturbing blood vessel walls or cell membranes to enhance drug permeability into malignant tissue using animal models. I have investigated the antiangiogenic effect of ultrasound focused targeted liposomal drug and the mechanism of enhanced drug delivery via cavitation in cellular level by observing of in vitro blood vessels on a microfluidic chip.