University of Wisconsin-Madison College of Engineering Annual Report 2003
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Chemical and Biological Engineering

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Programmed gene delivery

By delivering DNA rather than a drug, it may one day be possible to use gene therapy to treat disorders such as cystic fibrosis, cardiovascular disease and infectious diseases such as AIDS and cancer. The approach seeks to treat disease by modifying the expression of an individual's genes or correcting an abnormal gene. But effectively delivering DNA to its target without triggering other disease or side effects is proving a difficult challenge.

Assistant Professor David Lynn (left) is working to incorporate layers of DNA into nanothin, hydrolytically degradable polymer films. Ultimately these polymer films could be used to coat biomedical devices. Once implanted in the body, the films would degrade in response to specific physiological conditions and release therapeutic DNA to targeted cells.

David Lynn

Lynn's polymer films are designed to adhere to a device and carry a positive charge. The device can then be coated with a thin film of DNA, which is essentially a negatively charged polymer. By alternating nanothin coats of DNA and degradable polymer films in a specific sequence, Lynn hopes to release DNA to targeted cells from the surface of the coated devices.

Freeze drying could improve supply of stem cells and platelets

If you freeze one million embryonic stem cells, less than one percent will survive, say Professor Juan de Pablo and Assistant Professor Sean Palecek. Consequently, in storing stem cells for future experiments, scientists must freeze many millions in order to have enough to culture once thawed. Embryonic stem cells are of intense interest to medicine and science because of their ability to develop into virtually any other cell made by the human body. In theory, if stem cells can be grown and their development directed in culture, it would be possible to grow bone marrow, neural tissue, muscle or any of the other 220 cell types that make up the tissues and organs in the body.

A complete understanding of what happens to stem cells when frozen will not only shed light on how these amazing cells function but also could lead to a day when freeze-dried stem cells are stored at room temperature, shipped around the world and rehydrated to heal injuries. Working with stem cell pioneer James Thompson and the WiCell Research Institute, de Pablo and Palecek are conducting a physical, genomic and biochemical analysis of where damage occurs to platelets and stem cells during freezing and freeze drying, as well as the factors that help them survive. The project is part of a three-year, $1.3 million Defense Advanced Research Projects Agency (DARPA) grant.

Researchers engineer low-cost hydrogen catalyst

It's thousands of times less expensive than platinum and works nearly as well. Writing in the journal Science (June 27) Steenbock Professor James Dumesic and his graduate students reported the discovery of a nickel-tin catalyst that can replace the precious metal platinum in a new, environmentally sustainable, greenhouse-gas-neutral, low-temperature process for making hydrogen fuel from plants. The new catalyst, together with a second innovation that purifies hydrogen for use in hydrogen fuel cells, offers new opportunities toward the transition of a world economy based on fossil fuels to one based on hydrogen produced from renewable resources.

Dumesic and graduate students George Huber and John Shabaker describe testing more than 300 materials to find a nickel-tin-aluminum combination that reacts with biomass-derived oxygenated hydrocarbons to produce hydrogen and carbon dioxide without producing large amounts of unwanted methane.

In addition, Dumesic and graduate student Rupali Davda published findings regarding a new "ultra-shift" process that addresses a major obstacle in the efficient operation of hydrogen fuel cells. Carbon monoxide (CO) poisons the electrode surfaces of the devices, hampering their reliability. The "ultra-shift" process uses a platinum catalyst to achieve CO concentrations of 60 parts per million (PPM), much lower than 100 to 500 PPM levels produced through more common steam-reforming processes.

 





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Date last modified: Friday, 03-Oct-2003 12:56:00 CDT
Date created: 03-Oct-2003