Not much has changed in the world of sticky bandages since 1920, when Josephine Dickinson and her husband, Earle, an employee at Johnson & Johnson, stuck gauze to a piece of adhesive tape and invented the Band-Aid. A Hello Kitty top sheet and a little bit of antibiotic ointment on the inside may be the biggest developments.
But now, a group of mechanical engineers at MIT is trying to change things up. They've developed a bandage made from a stretchy, rubbery hydrogel. Embedded with a range of electronics and drug reservoirs, this "smart" dressing can actually monitor a wound, administer drugs and alert a doctor when more medicine is needed.
First, the team, led by professor Xuanhe Zhao, had to create a hydrogel that behaved like human skin. To accomplish this, they decided that the material, like skin, would have to be predominantly water. In November, Zhao revealed the results of the work—a hydrogel made of a thin web of biopolymers and composed of 90 percent water.
The material sticks to the metal or glass of electronic devices the way tendons stick to a bone. “Electronics are usually hard and dry, but the human body is soft and wet," Zhao told MIT News. “If you want to put electronics in close contact with the human body, it is highly desirable to make the electronic devices soft and stretchable to fit the environment.” Zhao and his colleagues just published a paper about their hydrogel bandages in the journal Advanced Materials.
To put the hydrogel to use, Zhao and his team ran titanium wire through it to make it conductive. They bonded electronics, such as temperature sensors, to the material, so that the bandage can detect any heat that is indicative of an infection. Then they drilled holes and cut channels in it to distribute medicine, like topical antimicrobials, across the injury. They even put LED lights in the bandage. Attached to the sensors, the LEDs light up when a wound reaches a concerning temperature. Eventually, since it's controlled remotely, the bandage could alert doctors through an app.
The engineers had to make sure it all still worked when it stretched, and that it could keep both rigid electronics, such as chips, and flexible ones, like wires, in place. Zhao is particularly interested in the interface between electronics and the human body, and trying to develop materials that closely mimic how we naturally move. The bandage bends in tricky spots, like on a knee or an elbow.
Zhao’s next goal is to use the material to build probes that can go inside the body and the brain. Neural probes, in particular, are incredibly hard to build, because the brain has a highly sensitive immune response to foreign objects.
“The brain is a bowl of Jell-O,” Zhao told MIT News. “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.”
Zhao says they’re not looking at commercialization quite yet. The bandage has not yet obtained FDA approval, but he says some of the earliest applications could be for dressing burn wounds, which need to be covered, monitored and treated.