For people living with Type 1 diabetes, low blood sugar—also called hypoglycemia—can be a constant and dangerous threat.
If blood sugar drops too far, it can cause confusion, seizures, or even death.
The usual emergency treatment is an injection of glucagon, a hormone that raises blood sugar levels by telling the liver to release stored glucose.
But emergencies can strike when patients are unaware of their low blood sugar—during sleep, for example, or in young children who cannot give themselves an injection.
Now, MIT engineers have developed a small implantable device that can store glucagon under the skin and release it instantly when needed. This device, about the size of a quarter, could give patients and their families peace of mind by being ready to act without delay.
“This is a small, emergency device that can be placed under the skin, where it’s ready to work if blood sugar drops too low,” says Daniel Anderson, senior author of the study and a professor at MIT. “We hope it will help protect patients and reduce the fear of hypoglycemia.”
The device could also be adapted to deliver other emergency medicines, such as epinephrine for severe allergic reactions or heart emergencies. In their study, published inmNature Biomedical Engineering, the researchers showed it worked effectively in mice.
Most people with Type 1 diabetes use insulin every day to control high blood sugar, but insulin can sometimes lower blood sugar too much. While some patients can sense when their sugar is falling and take action, others do not notice until it is dangerously low. This can be particularly risky at night or when alarms from glucose monitors fail to wake them.
The MIT team designed the new device so it can be triggered either manually or automatically. Inside is a small drug reservoir made from a 3D-printed polymer.
The seal is made of a shape-memory alloy—a nickel-titanium metal that changes shape when heated to about 40°C. When triggered, the metal bends, opening the reservoir and releasing the drug.
Because liquid glucagon breaks down quickly, the researchers used a powdered form that stays stable for much longer. The device can store one or four doses of glucagon and has a built-in antenna to receive radiofrequency signals.
When it gets the right signal, a small electric current heats the alloy, releasing the drug. In the future, the device could be linked to a glucose monitor so it would release glucagon automatically if sugar levels drop too low.
In tests with diabetic mice, the device released glucagon when blood sugar levels were falling. Within 10 minutes, the animals’ blood sugar stabilized, preventing severe hypoglycemia.
The researchers also tested it with powdered epinephrine, showing that the drug reached the bloodstream within minutes and caused the expected increase in heart rate.
The devices were kept under the skin for up to four weeks and still worked even after scar tissue formed around them. The team now hopes to extend the device’s lifespan to a year or more before it needs replacing. They plan further animal studies and aim to begin human trials within three years.
“This could help diabetic patients and open new possibilities for delivering any emergency medicine,” says Robert Langer, co-author of the paper.
The work was supported by the Leona M. and Harry B. Helmsley Charitable Trust, the National Institutes of Health, a JDRF fellowship, and the National Institute of Biomedical Imaging and Bioengineering.
If you care about diabetes, please read studies about New diabetes drug could control blood sugar and body weight better and findings of Common diabetes drugs linked to increased heart risk.
For more about diabetes, please read studies about Why diabetes drug metformin can help increase longevity and findings of This drug could manage type 2 diabetes for a long time.
The study is published in Nature Biomedical Engineering.
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