A new implantable device carries a reservoir of glucagon that can be stored under the skin and could save diabetes patients from dangerously low blood sugar. Credit: MIT
The new implant contains a reservoir of glucagon that sits beneath the skin and can be activated in an emergency, with no need for injections.
For
individuals with Type 1 diabetes, the risk of hypoglycemia, dangerously low
blood sugar, is a constant concern. When glucose levels drop too far, the
condition becomes life-threatening and typically requires an injection of the
hormone glucagon as the standard treatment.
To
address situations where patients may be unaware that their blood sugar is
falling to critical levels, MIT engineers have developed an implantable device
that holds a supply of glucagon beneath the skin. This device can be activated
to release the hormone automatically when glucose drops too low.
The
system could be especially useful during nighttime hypoglycemia or for young
children with diabetes who may not be able to self-administer an injection.
“This
is a small, emergency-event device that can be placed under the skin, where it
is ready to act if the patient’s blood sugar drops too low,” says Daniel
Anderson, a professor in MIT’s Department of Chemical Engineering, and a member
of both the Koch Institute for Integrative Cancer Research and the Institute
for Medical Engineering and Science (IMES). “Our goal was to build a device
that is always ready to protect patients from low blood sugar. We think this
can also help relieve the fear of hypoglycemia that many patients, and their
parents, suffer from.”
The
researchers also demonstrated that the same technology could be adapted to
deliver emergency doses of epinephrine, a medication used to treat heart
attacks and prevent severe allergic reactions such as anaphylaxis.
The
study was led by Siddharth Krishnan, a former MIT research scientist and now an
assistant professor of electrical engineering at Stanford University. The
findings were published on July 9, 2025, in Nature Biomedical
Engineering.
Emergency response
Many
people with type 1 diabetes rely on daily insulin injections to help regulate their blood
sugar and prevent it from rising too high. However, when blood sugar drops too
low, it can lead to hypoglycemia—a condition that may cause disorientation,
seizures, and in severe cases, death if not promptly treated.
To
address this, some individuals carry prefilled syringes of glucagon, a hormone
that signals the liver to release stored glucose into the bloodstream. Still,
recognizing the early signs of hypoglycemia can be challenging, particularly
for children.
“Some
patients can sense when they’re getting low blood sugar, and go eat something
or give themselves glucagon,” Anderson says. “But some are unaware that they’re
hypoglycemic, and they can just slip into confusion and coma. This is also a
problem when patients sleep, as they are reliant on glucose sensor alarms to
wake them when sugar drops dangerously low.”
To
provide a more reliable solution, the MIT team developed a compact emergency
device that can be activated manually or automatically in response to low blood
sugar, based on sensor input.
Roughly
the size of a quarter, the device houses a small drug reservoir fabricated
using 3D-printed polymer. This reservoir is sealed with a material called a
shape-memory alloy, engineered
to change form when exposed to heat. The team used a nickel-titanium alloy that
transitions from a flat slab to a U shape when heated to 40 degrees Celsius.
Since
glucagon, like many peptide-based drugs, degrades quickly in liquid form, the
researchers opted for a powdered formulation that remains stable over extended
periods and stays inside the device until needed.
The researchers showed that this device could also be used to deliver emergency doses of epinephrine, a drug that is used to treat heart attacks and can also prevent severe allergic reactions, including anaphylactic shock. Credit: MIT
Each
unit can store one or four doses of glucagon and contains an antenna that
responds to a specific radiofrequency signal. When triggered, the antenna
activates a small electrical current that heats the shape-memory alloy. Once
the material reaches the activation temperature, it bends into a U shape and
releases the powdered drug from the reservoir.
Because
the device can receive wireless signals, it could also be designed so that drug
release is triggered by a glucose monitor when the wearer’s blood sugar drops
below a certain level.
“One
of the key features of this type of digital drug delivery system is that you
can have it talk to sensors,” Krishnan says. “In this case, the continuous glucose-monitoring
technology that a lot of patients use is something that would be easy for these
types of devices to interface with.”
Reversing hypoglycemia
After
implanting the device in diabetic mice, the researchers used it to trigger
glucagon release as the animals’ blood sugar levels were dropping. Within less
than 10 minutes of activating the drug release, blood sugar levels began to
level off, allowing them to remain within the normal range and avert
hypoglycemia.
The
researchers also tested the device with a powdered version of epinephrine. They
found that within 10 minutes of drug release, epinephrine levels in the
bloodstream became elevated and heart rate increased.
In
this study, the researchers kept the devices implanted for up to four weeks,
but they now plan to see if they can extend that time up to at least a year.
“The
idea is you would have enough doses that can provide this therapeutic rescue
event over a significant period of time. We don’t know exactly what that is —
maybe a year, maybe a few years, and we’re currently working on establishing
what the optimal lifetime is. But then after that, it would need to be
replaced,” Krishnan says.
Typically,
when a medical device is implanted in the body, scar tissue develops around the
device, which can interfere with its function. However, in this study, the
researchers showed that even after fibrotic tissue formed around the implant,
they were able to successfully trigger the drug release.
The
researchers are now planning for additional animal studies and hope to begin
testing the device in clinical trials within the next three years.
“It’s
really exciting to see our team accomplish this, which I hope will someday help
diabetic patients and could more broadly provide a new paradigm for delivering
any emergency medicine,” says Robert Langer, the David H. Koch Institute
Professor at MIT and an author of the paper.
Reference:
“Emergency delivery of particulate drugs by active ejection using in vivo
wireless devices” by Siddharth R. Krishnan, Laura O’Keeffe, Arnab Rudra, Derin
Gumustop, Nima Khatib, Claudia Liu, Jiawei Yang, Athena Wang, Matthew A.
Bochenek, Yen-Chun Lu, Suman Bose, Kaelan Reed, Robert Langer and Daniel G.
Anderson, 9 July 2025, Nature
Biomedical Engineering.
DOI: 10.1038/s41551-025-01436-2
The
research was funded by the Leona M. and Harry B. Helmsley Charitable Trust,
the National Institutes of Health,
a JDRF postdoctoral fellowship, and the National Institute of Biomedical
Imaging and Bioengineering.
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