'Smart' Insulin Patch Could Replace Painful Injections For People With Diabetes

Jul 31, 2015

Pricking your finger and meticulously checking your blood sugar could no longer be the only way people with diabetes handle the disease.  Researches from the University of North Carolina at Chapel Hill and N.C. State University are working to replace this painful process with a thin square patch the size of a penny.

It is a “smart insulin patch” that can detect increases in blood sugar levels. The patch has more than a hundred tiny microneedles, each about the size of an eyelash.

Each microneedle has tiny sacs called vesicles that contain insulin. When blood sugar levels get too high, the patch detects it and sends the vesicles’ cargo of insulin into the bloodstream.

“We want to make the design simple. Sometimes simple is the best,” said Zhen Gu, Ph.D., a professor in the Joint UNC/NC State Department of Biomedical Engineering. “The whole system can be personalized to account for a diabetic’s weight and sensitivity to insulin, so we could make the smart patch even smarter.”

Gu leads development of the patch’s painless polymer microneedles. The patch is intended to help people with type 1 and advanced type 2 diabetes control their blood sugar levels without imprecise and risky finger-pricking and insulin injections.

“Injecting the wrong amount of medication can lead to significant complications like blindness and limb amputations, or even more disastrous consequences such as diabetic comas and death,” said John Buse, M.D., Ph.D. and director of the UNC Diabetes Care Center. Buse and Gu were both co-senior authors of a study about the “smart” patch in the Proceedings of the National Academy of Sciences.

An up-close look at the microneedles on the 'smart' patch
Credit UNC School of Medicine / UNC Health Care

21 million people have been diagnosed with diabetes in the United States. In 2011, about 11% of people in North Carolina had diabetes, and the disease was the seventh leading cause of death in the state. Gu said more people are being diagnose with diabetes because of lifestyle factors like obesity and lack of exercise.

“That is why diabetes education is also very important. We need to treat diabetes patients, but also control the increase in the population of diabetes,” he said. “This could be the future.”

It might be the patch of tomorrow, but Gu said the goal is to make it affordable and efficient. Right now, he said each patch lasts about half a day, but the team is tweaking the patch to make it last two days to even one week.

Here is how the patch works: the vesicles are like a microscopic warehouse with an alarm system. When blood sugar levels get too high, the patch detects it and gathers the excess glucose in its artificial vesicles. Enzymes in the vesicles suck out all of the glucose’s oxygen, causing the vesicles to fall apart. This releases the insulin stored in the vesicles to flow into the bloodstream. This is all done without a prick of the finger, making life for people with diabetes less painful and more convenient.

“The hard part of diabetes is not the insulin shots, or the blood sugar checks, or the diet, but the fact that you have to do them all several times a day for the rest of your life,” Buse said.

For Gu, inventing the “smart” patch means helping millions with the disease, especially those close to home.

“I have some relatives with diabetes, my grandmother had it, Gu said. “I am a medical engineer and we always want to develop something for people, especially the people around you in your home and in your family.”

The researchers successfully lowered the blood sugar levels with the patch in mouse models. They will continue to develop the patch before testing it on humans, a process that Gu said may take several years, but shows great promise.