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  September 4, 2001

Research Focuses on Implantable
Glucose Monitor for Diabetics

Francis Moussy, a researcher at the Center for Biomaterials at the Health Center, has had more than a passing interest in diabetes since he watched a cousin learn how to deal with the disease when they were both teenagers in France.

"He had to be careful about what he ate and drank, and that made it difficult for him to hang out with friends at restaurants and clubs," says Moussy, an assistant professor.

Care is necessary because people with diabetes do not produce adequate amounts of insulin, the hormone that helps the body use sugar as a fuel. Instead, they need insulin injections.

Research on a possible cure for the disease captured Moussy's attention in college at the University of Reims, France, where he received a bachelor's degree in natural sciences. During his graduate work in biomedical engineering at the UniversitŽ de Technologie de Compigne in France, he worked on developing an artificial pancreas, the organ that produces insulin. At the postdoctoral level, Moussy moved to the mechanical engineering department at the University of Toronto and then to the chemistry department at the University of Alberta. There he got involved in research to develop an implantable glucose sensor.

"The sensor would be a huge step forward in quality of life for the millions of people who have diabetes," says Moussy, who moved to the Center for Biomaterials in 1996 to continue his work.

Research has demonstrated that precise control of glucose levels can delay and prevent many of the devastating complications of diabetes, such as kidney disease, blindness and limb amputation. But because the finger pricks are painful and time-consuming, people with diabetes often resist performing an adequate number of the tests, according to Moussy. Some patients, especially young children, may need the glucose monitoring tests every two hours, including throughout the night.

A reliable sensor permanently implanted in the body could provide pain-free, reliable and continuous glucose monitoring. The readings would be transmitted to a watch-like receiver worn on the wrist that would signal alarms for low and high glucose levels.

To date, Moussy and colleagues at the Storrs campus and at Columbia University have developed a sensor smaller than a grain of rice that uses an enzymatic reaction to measure blood glucose levels.

To prevent inflammation and the build up of scar tissue, they coat the sensor with new biomaterials - tiny "microspheres," or beads of a biodegradable polymer that can be filled with different chemicals. These beads gradually degrade in the body, releasing medicines to control inflammation and the growth of scar tissue that eventually interfere with the reliability of the sensor. The timing could be adjusted to last up to 10 years before the device would have to be replaced.

For the sensor to work accurately, Moussy and his colleagues have to control the body's response to the device. "The body has evolved defenses to foreign bodies. It tries to destroy them or entomb them," he says. "The resulting inflammation and scar tissue prevents the sensor from making accurate readings." So far, most implanted sensors have worked reliably for only three days or less.

"Recent advances in molecular biology are helping us understand how to control the tissue reaction to the sensor," says Moussy, whose work is supported by grants from the National Institutes of Health and the Juvenile Diabetes foundation.

He and his colleagues are poised to take advantage of these advances through a collaboration that brings together the fields of biomedical engineering, polymer science, pharmaceuticals, and tissue trauma. "It is the collaboration that will make this work," says Moussy, who admits that the coordination of these diverse sciences and scientists is a daunting task.

Initial tests of the coated sensors have been promising and Moussy has applied for patents for the device. "We will probably hear about our patent applications in about a year," he says. "Once we get the patents, our work will move ahead more quickly because it will be easier to find a company to invest in the device," he says. "It's a question of time and resources."

The research team includes: Donald Kreutzer, professor of pathology; Samuel Huang, professor of chemistry; Fotios Papadimitrakopoulos, associate professor of chemistry; Diane Burgess, professor of pharmaceutical sciences; and Jeffrey Koberstein, formerly professor of chemical engineering at UConn, now at Columbia University.

Kristina Goodnough

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