Dubbed, a “smart wound dressing,” the hydrogel releases medicine in response to skin temperature changes and can even be programmed to alert users if medication levels are low.
“Electronics are usually hard and dry, but the human body is soft and wet. These two systems have drastically different properties,” explained Xuanhe Zhao, the Robert N. Noyce Career Development Associate Professor in MIT’s Department of Mechanical Engineering, and the designer of the hydrogel matrix.
“If you want to put electronics in close contact with the human body for applications such as health care monitoring and drug delivery, it is highly desirable to make the electronic devices soft and stretchable to fit the environment of the human body. That’s the motivation for stretchable hydrogel electronics.”
Mostly comprised of water, the hydrogel is a rubbery material designed to bond to surfaces, such as gold, titanium, aluminum, silicon, glass, and ceramic, as well as nonporous surfaces.
In a paper published in the journal Advanced Materials, the team also reported embedding various electronics within the hydrogel, such as conductive wires, semiconductor chips, LED lights, and sensors.
A high-tech Band-Aid
To create the “smart wound dressing,” the team embedded temperature sensors within a sheet of the hydrogel before either inserting patterned tubes or drilling holes through the matrix to create the drug delivery pathways.
When the dressing was placed on various parts of the body the researchers found that it could continually monitor skin temperature and release drugs according to the readings – even when stretched.
“It’s a very versatile matrix,” said Hyunwoo Yuk, a graduate student and one of the paper’s coauthors. “The unique capability here is, when a sensor senses something different, like an abnormal increase in temperature, the device can on demand release drugs to that specific location and select a specific drug from one of the reservoirs, which can diffuse in the hydrogel matrix for sustained release over time.”
One immediate application of the technology could be as an on-demand treatment for burns or other skin conditions; however, the hydrogel could be used to deliver electronics inside the body in the future.
“The brain is a bowl of Jell-O,” Zhao added. “Currently, researchers are trying different soft materials to achieve long-term biocompatibility of neural devices. With collaborators, we are proposing to use robust hydrogel as an ideal material for neural devices, because the hydrogel can be designed to possess similar mechanical and physiological properties as the brain.”