Ohio State University researchers work on ‘stick-free’ blood glucose monitor

COLUMBUS, Ohio — Diabetes has a substantial impact on the quality of sufferers’ lives.

So Ohio State University doctoral student Louis Nemzer decided he wanted to do something to make the lives of diabetic patients a little easier — he is leading an effort to develop a continuous blood glucose meter that doesn’t require pricking the skin to do its job.

That’s right, no finger sticks to get blood to analyze for its sugar content. Nemzer’s meter does its work with light, color and an enzyme-embedded polymer. If successful developed, his continuous blood glucose monitor could be part of a closed-loop system that functions like an artificial pancreas — a Holy Grail for diabetes researchers.

“This is an opportunity for new medical devices to alleviate some of  [the suffering],” said Nemzer, who is getting a PhD in physics. He recruited one of his physics professors, Arthur Epstein, known for his research on the optical and magnetic properties of materials, holder of more than 30 patents or patents pending, and founding director of the university’s Center for Materials Research.

“The key issue for diabetics in treatment is how can they maintain a uniform glucose level in the bloodstream … not be too low, not be too high,” Epstein said. “That’s where insulin pumps come in. But in order for insulin pumps to work, you need to know the blood glucose level.”

Insulin pumps are part of experimental closed-loop systems that could do the work of the pancreas. Among other things, the pancreas produces insulin, the hormone that “unlocks” the cells of the body, enabling the cells to use sugar, starches and other substances in the bloodstream as fuel, according to the American Diabetes Association.

Lacking insulin — the main symptom of diabetes – cells can’t use sugar, leaving it to build up in the bloodstream where it devastates blood vessels and organs. Most diabetics use devices to keep track of their blood sugar levels so they can dose themselves with insulin and other medicines, or have a snack. Insulin pumps, which can do the dosing, also need to measure blood sugar levels to do their work.

The best way to measure blood sugar is directly — diabetics usually prick their skin to draw blood so they can measure its sugar content. “People get tired of that,” Epstein said. Diabetics also can get infections from pricking their skin. “So people don’t do it as frequently during the day as they should. And they don’t do it night.

“Endocrinologists feel that if they could do it … nearly continuously, then they could monitor the disease better and treat it better,” he said. “So it’s a continuous glucose monitor that we’re working on.”

Patients and insulin pumps must have information about blood glucose levels to work properly. “We talk a lot about closing the loop,” Nemzer said. “We have the technology to administer insulin, these pumps. But we need to close that loop with information from the body.

“That’s the ultimate goal, but it’s been elusive,” he said. “People have been thinking about this for 20 years. There’s been some recent progress … but I feel there is an opportunity for our group because this non-invasive continuous glucose monitoring system that you can wirelessly connect to an insulin pump is not here yet.”

Using results from Epstein’s research on the optical properties of materials, Nemzer and Epstein proposed using light and color to measure glucose level in the blood. That’s how fingertip blood-oxygen monitors, called pulse oximeters, measure oxygen in the blood.

Trouble is, the wavelengths of light that indicate glucose in the blood can’t be detected through the skin, Epstein said. “So another way has to be developed. You can’t do as you do with the oxygen dosimeter,” he said.

Epstein helped Nemzer find a polymer that is biocompatible — that is, it’s easily accepted by the body. The two are working on ways to impregnate the polymer with an enzyme that turns colors to indicate the concentration of glucose in the blood. The polymer and enzyme would be mounted on a tiny implant just under the skin that would reflect the changing colors to a watch-like reader on the wrist. 

The reader could give the wearer a digital display indicating the level of glucose in the blood. It also could alarm when blood glucose rises too high or falls too low so the wearer can take insulin or eat something to solve the problem. The reader also could connect wirelessly to an insulin pump or a computer that keeps logs of blood sugar levels, Nemzer said.

How close are the researchers to having a system that could be commercialized?

“Louis has fabricated these polymer sensors and coated them on various substrates. And we’ve done studies so far with artificial fluids” to demonstrate and measure the sensors’ color-changing abilities, Epstein said. “He’s even gone so far as to demonstrate that you can do this reflective study through [animal] skin tissue.”

It will take some time to get the university approvals needed to test the system in live animals, Epstein said. A patent has been filed on the system, and Nemzer has disclosed his research to groups at the American Physical Society and the Materials Research Society.

“To get this to help people, it has to become commercial,” said Epstein, who hopes that eventually a company will be interested enough to license the technology. “First of all, it has to be studied further at the laboratory level, followed by studies with animals and subsequently in humans. It takes a lot of resources to do that.”