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UW-Madison engineers present at ACS

Sean P. Palecek

Sean P. Palecek (large image)

Juan J. de Pablo

Juan J. de Pablo (large image)

David M. Lynn

David M. Lynn (large image)

Several University of Wisconsin-Madison engineers presented findings at the American Chemical Society’s national meeting Sept. 10 through 14 in San Francisco. Among them, two presentations highlighted research that could benefit cardiac health and stem cell research.

Clearing clogged arteries with DNA-coated stents

New materials hold promise for treating cardiovascular diseases with gene-based therapy using intravascular stents, small tubes of metal mesh that are commonly inserted into arteries to keep them open after angioplasty. Led by Chemical and Biological Engineering Assistant Professor David Lynn, a team has developed methods to coat stents with films of nanostructured layers of DNA and cationic polymers. The polymers degrade and DNA is released into the surrounding cells.

This approach is similar to a current method used to coat stents with small-molecule drugs. “While current stent coatings work well for releasing traditional drugs, they were not designed to release nucleic acid-based drugs,” says Lynn.

One important application of localized gene-based therapy is the prevention of restenosis, a common problem with metal stents, in which smooth muscle tissue grows over and around the stent, which can re-clog the artery.

Lynn presented his findings Sept. 14 at the meeting.

Improving stem cell production

In a typical culture, human embryonic stem cells (hESC) grow in colonies that are mixed in size and shape. These colonies often spontaneously differentiate, making it time- and labor-intensive to maintain undifferentiated cells.

Graduate student Jeffrey Mohr, Howard Curler Distinguished Professor Juan de Pablo, and Associate Professor Sean Palecek have developed microwell arrays, or trays with microscopic wells, to grow undifferentiated hESC cultures with defined sizes and shapes. The insides of the wells are coated with a substance that absorbs protein, so the cell aggregates will grow inside the wells, while the area outside of the wells is coated with a substance to prevent cell attachment, so the cells will not spread outside the wells.

In the trio’s experiments, the hESCs grown in the microwells not only remained undifferentiated, but they also retained their self-renewal and ability to become different cell types. The wells in the trays can be manufactured in different sizes and shapes, so that larger or smaller aggregates can be cultured.

“When you culture stem cells in these very small microwells, we can actually control the growth of these cells and the size and shape of the aggregates that result,” says de Pablo. “This is extremely important for application of stem cells because the size of these colonies influences the differentiation and eventual fate of the cells.”

Jeff Mohr presented these findings in a Sept. 13 poster session at the meeting.

Archive
9/14/2006