A joint North Carolina State University and University of North Carolina research project aims to replace insulin injections with an insulin patch.

Dr. Zhen Gu, a professor at the schools' Joint Department of Biomedical Engineering, says the work aims to make administering insulin autonomous for patients.

"Basically we developed this kind of so-called smart insulin patch, which can sense the blood sugar level and release insulin at the right time only once the blood sugar goes up. And the insulin can be quickly released from the patch. And meanwhile once the blood sugar level goes to a normal range, less insulin is released or is just inhibited. Basically this kind of smart insulin patch is not only smart, it is also painless," Gu says.

For the 21 million Americans diagnosed with diabetes and the more than 387 million world-wide affected by the disease, insulin injections and attached insulin pumps could become things of the past.

Gu and others at the lab found a way to fit more than 100 microneedles onto the patch, which is less than the size of a dime. Each microneedle is filled with insulin and enzymes that can tell when blood sugar levels change.

"Basically we designed this kind of material - a polymer-based material, which can be sensitive to blood sugar level changes," Gu says. "We are trying to mimic the functioning of the beta cells or the vesicles inside the beta cells and they can disrupt once the blood sugar goes up and release insulin quickly."

Currently the patch works for up to nine hours, according to a recent study, but Gu hopes they can design it to last for several days.

This measure, Gu says, will decrease the chance of human error when administering insulin shots, which he says can be imprecise both in location and in the amount of insulin injected.

Administering too much insulin can induce hypoglycemia when blood sugar levels fall too much. In the worst cases, it could result in death.

The patch has been tested on mice and other animals and so far the results are promising, Gu says.

"We are very proud of our technology and we really want to translate it as fast as possible. Currently we are working with our collaborators and testing it on animals like mini pigs in a study. If this mini pig study successfully demonstrates it, we will move to the human being testing immediately," Gu says.