Aimee Leonhard, a former museum curator from Columbia, knows better than most people about the symptoms, treatment, and potentially grim realities of diabetes. At age 43, she was diagnosed with the more rare type 1 form of the disease, which develops when the body's immune system destroys pancreatic beta cells, the only cells that make the hormone insulin that in turn, regulates blood glucose.
Thus has Leonhard been plunged into daily rounds of pinpricks, blood glucose monitoring, and insulin injections -- a regimen that is painfully familiar to the more 18 million Americans with the disease. "The scary thing about diabetes is what can happen to you: blindness from glaucoma, amputations, kidney failure," she says. "It's a gruesome picture. But recent studies have shown that if you keep your blood glucose level down, you can avoid most of those complications."
So Leonhard makes sure her glucose stays where it should be. In practice, this means pricking a fingertip with a small, pen-shaped lancet. After a drop of blood appears, she dabs it on a small, disposable test strip attached to a pocket calculator-sized monitoring device. It takes a few seconds for "the vampire," as Leonhard has dubbed the monitor, to indicate on its small screen the glucose level in her bloodstream. She then dutifully records the number in a journal. She repeats the process six times each day.
"This tells me how I'm doing and how much insulin to inject," Leonhard says. "Theoretically, you should be checking your glucose all the time. I only get a reading six times in a day, and it's like walking a tightrope. If it gets too low, you can pass out."
Sheila Grant, assistant professor of biological engineering at MU, is researching devices that may one day offer relief to people like Leonhard who have diabetes, as well as to others suffering from a host of other health problems.
Grant is researching optical base biosensors, electrical devices that can detect, record, and transmit information about biological elements in the body, pollutants in water or food, and toxins in the air. Biosensors may one day alert an otherwise healthy 50-year-old to the earliest signs of heart attack, help an HIV patient monitor his viral load and subsequent dose of medication, or enable a diabetic like Leonhard to read her glucose level any time, day or night, with just a glance. The technology also holds promise for environmental sensors that could be used to warn of chemical attacks.
Consumer-ready biosensors are still a long way off: improvements in their sensing accuracy, fabrication, and cost-efficiency still need to come. But Grant and her students are working to speed that research along. "It's an exciting field because the potential for their applications is so broad, and the technology has the potential to help people in many different situations," says Grant. She works in MU's Biosensors and Biomaterials Research Laboratory in the biological engineering department, where her projects include developing implantable sensors for humans and a sensor that measures the tenderness of meat. She is also studying how to refine sensors' sensitivity and ways to "trick" the body into accepting biosensors once they have been implanted.
Sensors have been around for decades, used to detect everything from high fevers and low oxygen, to speeding cars and evidence of life on other planets. A mercury thermometer is an example of a mechanical sensor. Paper strips you dip into your hot tub or aquarium to test the pH are sensors, too.
"Peel an apple," says Steve Lane of the Lawrence Livermore National Laboratory just east of San Francisco, "and in a while you'll see it turn brown. You could call that an oxygen sensor. The idea of biological sensors is an old one, and building one can be fairly simple. But building one with practical uses and then getting it to operate in the human body is exceedingly difficult."
The research community for biosensors is diverse and diffuse, says Lane, combining the expertise of engineers, chemists, physicists, biologists, and doctors. Their common goal is to develop sophisticated sensors that can detect all sorts of biological elements in the environment or in living things.