Smart patch to monitor glucose, secrete insulin shows promise in preclinical study

Smart insulin patch--Courtesy of University of North Carolina

Researchers at the University of North Carolina and North Carolina State are developing a smart insulin patch that could be worn for a few days and effectively monitor blood glucose levels to trigger the secretion of insulin. An artificial pancreas in a patch, if you will.

The researchers have tested their new patch successfully in a mouse model of Type 1 diabetes for up to 9 hours. A paper on the results is in the latest issue of the Proceedings of the National Academy of Sciences (PNAS). They expect to do further preclinical testing prior to advancing into human clinical trials.

The researchers noted that this is the first time that a synthetic glucose-responsive device using a hypoxia trigger for regulation of insulin release has been shown effective.

"We have designed a patch for diabetes that works fast, is easy to use, and is made from nontoxic, biocompatible materials," co-senior author Zhen Gu, a professor in the joint UNC/NC State department of biomedical engineering, said in a statement. "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."

The patch is a thin square, about the size of a penny, that is covered with 100 microneedles, each about the size of an eyelash. These tiny needles store both insulin and glucose-sensing enzymes that are triggered to release the insulin when blood glucose levels rise.

Most approaches to an artificial pancreas, which would fully automate the process of monitoring blood glucose and administering the appropriate dose of medication to address patient needs, involve systems that include mechanical sensors and pumps that work via needle-tipped catheters. Some implants or devices using pancreatic cells are also being researched. But these researchers attempted to emulate the natural insulin generation in beta cells by creating patches that both track blood sugar levels and release insulin into the bloodstream.

"We constructed artificial vesicles to perform these same functions by using two materials that could easily be found in nature," said PNAS first author Jiching Yu, a PhD student in Gu's lab.

In the preclinical testing, researchers compared the reaction that Type 1 diabetes model mice had to standard insulin injection and blood glucose levels versus their microneedle patch. They found that the former had glucose levels that quickly dropped down to normal and then quickly climbed back into the hyperglycemic range, while the latter had blood glucose levels that were brought under control within 30 minutes and remained that way for several hours.

The researchers found that they could fine-tune the patch to maintain a particular blood glucose range by varying the amount of enzyme in each microneedle.

"The hard part of diabetes care 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 every day for the rest of your life," said co-senior author Dr. John Buse, director of the UNC Diabetes Care Center and the North Carolina Translational and Clinical Sciences Institute and past president of the American Diabetes Association.

"If we can get these patches to work in people, it will be a game changer," he concluded. The researchers noted that humans are more sensitive to insulin than mice, which suggests that a patch could be effective over a period of several days.

- here is the release and the paper

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