Compared to frequent insulin injections, Doyle says, pumps seem to provide patients with improved control of their blood-sugar levels, so that they're less vulnerable to diabetes-related health problems.

Smart pumps on the horizon?

But, existing implantable designs simply deliver a low dose of insulin on a continuous basis, Parker notes. Patients also can self-administer additional insulin before a meal.

"By developing glucose sensors and predictive algorithms for these devices," Parker says, "we hope to dramatically improve and automate the control of blood-sugar levels."

Highly precise control is important because sugar concentrations above the normal level of 70 to 120 milligrams of glucose per deciliter of blood (mg/dl) have been associated with liver damage, blindness and other medical problems. And, cells begin to starve when blood-sugar levels fall too low.

So, UD researchers are working on "a smarter brain for the next generation of implantable insulin pumps," Doyle says. "In the future, our system could fit on a computer chip, processing glucose sensor information, and then translating that data into pump action."

Predicting the body's insulin needs

Traditionally, mathematical commands or algorithms for controlling blood-sugar levels have been "like a thermostat-either on or off," Doyle says. "The classic approach has been a bang-bang type of algorithm," he added. "When sugar levels are high, these systems deliver a dose of insulin. When sugar is low, they turn insulin delivery back down."

Unfortunately, this approach isn't "meal-proof," Doyle says, and it doesn't reflect dramatic variations among individuals. In other words, "These algorithms can't predict and plan ahead for the increase
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Contact: Ginger Pinholster
gingpin@udel.edu
302-831-6408
University of Delaware
6-Jun-1999