A new ‘smart’ insulin patch could replace painful insulin injections and revolutionise how people with diabetes monitor and manage their blood sugar levels.
Researchers from the University of North Carolina and NC State have created a “smart insulin patch” that can detect increases in blood sugar levels and secrete doses of insulin into the bloodstream whenever needed.
Patients with Type I and advanced Type II diabetes try to keep their blood sugar levels under control with regular finger pricks and insulin shots, a process that is painful and imprecise. Injecting the wrong amount of insulin can lead to serious complications and in some cases lead to diabetic comas and death.
A study showed that the painless patch could lower blood glucose in a mouse model of Type I diabetes for up to nine hours. While the study shows great promise, more tests and clinical trials are needed before proceeding to human trials.
“We have designed a patch for diabetes that works fast, is easy to use, and is made from nontoxic, biocompatible materials,” said co-senior author Zhen Gu, PhD.
The thin square patch is covered with more than one hundred tiny painless needles, each the size of an eyelash. The “micro needles” are packed with microscopic storage units for insulin and glucose-sensing enzymes that rapidly release insulin when blood sugar levels get too high.
The researchers chose to mimic the body’s natural insulin generators known as beta cells. These versatile cells act both as factories and warehouses, making and storing insulin in tiny sacs called vesicles. They also sense changes in blood sugar and signal the release of 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.
The researchers created a new molecule by combining hyaluronic acid (HA) used in cosmetics and 2-nitroimidazole (NI), an organic compound used in diagnostics, to form a molecule that is water-loving at one end (the HA part) and water-repellent at the other (the NI part). A mixture of these molecules self-assembled into a vesicle in the same way that oil droplets do in water.
As a result, millions of bubble-like structures, each 100 times smaller than the width of a human hair were formed. Each of the artificial vesicles is inserted with a core of solid insulin and enzymes designed to detect glucose.
After designing the smart patch, researchers had to figure out a way to administer the artificial vesicles to diabetic patients. Rather than rely on large needles or catheters the researchers decided to incorporate these balls of sugar-sensing, insulin-releasing material into an array of tiny needles.
The researchers created a silicon strip with over a hundred “micro needles” using the same hyaluronic acid only in a more rigid form so the tiny needles were stiff enough to pierce the skin and tap into the blood flowing through the capillaries below.
The researchers tested the approach in a mouse model of Type I diabetes. They gave one group of mice a standard insulin injection and found that the blood glucose levels dropped to normal but quickly rose to hyperglycemic levels. But the results were different in another group of diabetic mice treated with the smart patch. The blood glucose levels were brought under control within thirty minutes and stayed that way for a couple of hours.
Because mice are less sensitive to insulin than humans, the researchers anticipate that the patch could last even longer in humans. The researchers’ ultimate goal is to develop a smart insulin patch that patients would only have to change every few days.
“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 Director of the North Carolina Translational and Clinical Sciences Institute, John Buse, MD, PhD. “If we can get these patches to work in people, it will be a game changer.”