A pain-free, skin patch that responds to blood sugar levels and helps manage type 2 diabetes

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The new ‘smart’ skin patch could be a game-changer for patients with type-2 diabetes

Concept illustration of microneedle device for type 2 diabetes treatment. Chen lab, NIBIB.
Concept illustration of microneedle device for type 2 diabetes treatment. Chen lab, NIBIB.

Type-2 diabetes is a progressively worsening condition in which the body’s ability to make or use insulin slowly deteriorates. Insulin is produced by the pancreas and is the key molecule that’s required to shift glucose from the bloodstream into the cells of tissues that need it for energy. When left untreated, type 2 diabetes affects multiple organs and can result in irreversible damage to the eyes, feet, nerves, kidneys and heart.

To maintain their health, millions of diabetic patients around the world need to persistently monitor their blood glucose levels and take routine insulin shots through the day. This involves frequent finger-prick tests and insulin injections.

Diabetic patients have to carefully calculate and administer their insulin shots. In type 1 diabetes, there is no production of insulin at all. In type 2 diabetes, the injection doses depend on the individual’s activities, as well as their body’s basal, though lessened production of insulin.

Managing type 2 diabetes with insulin therapy is not done correctly in half of all the cases. Over the past year, scientists from research and healthcare sectors of diabetes treatment have been exploring minimally invasive alternative approaches to monitor and regulate blood glucose.

The current NIH study

Researchers from NIH’s National Institute of Bio-Imaging and Bioengineering (NIBIB) have recently devised a microneedle skin patch that could offer a painless and hassle-free alternative for managing type 2 diabetes.

The microneedles are infused with an innovative mix of mineralized compounds that respond to changes in blood chemistry caused by glucose. High levels of glucose trigger a chemical reaction in the patch, releasing a compound called exendin-4. Exendin-4 mimics the action of a naturally occurring hormone in our intestine and augments pancreatic production of insulin.

When tested on mice, the skin patch was effective in automatically regulating blood glucose levels for up to a week. The results were published online in Nature Communications.

“This experimental approach could be a way to take advantage of the fact that persons with type 2 diabetes can still produce some insulin,” said Richard Leapman, NIBIB Scientific Director. “A weekly microneedle patch application would also be less complicated and painful than routines that require frequent blood testing.”

The research was led by Xiaoyuan Chen, Senior Investigator in the Laboratory of Molecular Imaging and Nanomedicine, NIBIB.

“Diabetes is a very serious disease and affects a lot of people,” said Chen. “Everybody is looking for a long-acting formula.”

Artists concept of drug interaction to treat type 2 diabetes
Illustration to represent glucose-responsive exendin-4 delivery with a micro-needle patch. At left, relatively lower glucose levels (turquoise) in blood induce a mild chemical reaction with the compounds in the patch, which is not sufficient to release exendin-4. At right, when blood glucose concentration rises, acidity in blood triggers rapid release of exendin-4 (pink) for blood glucose regulation. Chen lab, NIBIB.

Chen’s team infused the skin patch with two drugs, exendin-4 and glucose oxidase, and matched them with a phosphate mineral buffer to stabilize them until they are needed. Elevated levels of glucose in the blood react with glucose oxidase and its mineral buffer, causing a slight acidity which triggers the release of exendin-4 from its mineral phosphate. Once exendin-4 stimulates pancreatic secretion of insulin, blood glucose drops again and curtails exendin-4 release.

“That’s why we call it responsive, or smart, release,” said Chen. “Most current approaches involve constant release. Our approach creates a wave of fast release when needed and then slows or even stops the release when the glucose level is stable.”

The patch is made of alginate, a pliable and biocompatible substance extracted from brown algae. The alginate needles can poke the skin, but are soft enough to be painless. The patch needs to be tested on larger animals before it can be developed further for people, and may also need to be altered for human skin requirements.

“We would need to scale up the size of the patch and optimize the length, shape, and morphology of the needles,” Chen said. “Also, the patch needs to be compatible with daily life, for instance allowing for showering or sweating.”

The skin patch involves minimal patient interaction and is not currently linked to any software or digital monitoring devices. It could soon be a welcome addition to the treatment strategies that are currently available for managing diabetes.

Source: NIBIB