Flexible Hydrogel Technology
Engineers from MIT have created what many consider to be a futuristic Band-Aid – an adhesive, flexible, gel-like substance that can include various forms of technology such as temperature sensors and LED lights. Along with that, this substance can include tiny canals to transport medication into the body. This technology works as follows: once a change in skin temperature is detected by the sensors, medicine will be released through the canal into the body. What about the LED lights? Well, it’s possible to make those light up when you’re running out of medicine.
You know the hassle of needing to put a bandage on a flexible area like the knee or elbow? The adhesive always seems to come off because it can’t keep up with the movement. That is a non-issue for these bandages of the future. The adhesive substance stretches with the body and keeps the attached electronics in working order.
An Associate Professor in MIT’s Department of Mechanical Engineering by the name of Xuanhe Zhao is responsible for creating the hydrogel matrix that is the base of this design. This hydrogel is a rubbery substance that is almost entirely made up of water, which is intended to strongly bond itself to gold, titanium, aluminum, silicon, glass, and ceramic surfaces.
In a document distributed in the scientific journal Advanced Materials, the group documents the installation of different hardware inside of the hydrogel, for example, conductive wires, semiconductor chips, LED lights, and temperature sensors. Zhao says hardware covered in hydrogel may be utilized on the surface of the skin as well as inside the body, for instance as embedded, biocompatible glucose sensors, or even delicate, consistent brain probes.
Zhao remarked that, “Electronics are usually hard and dry, but the human body is soft and wet. These two systems have drastically different properties. 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.”
Zhao’s document was co-authored by graduate students Shaoting Lin, Hyunwoo Yuk, German Alberto Parada, post-doctoral student Teng Zhang, Hyunwoo Koo from Samsung Display, and Cunjiang Yu from the University of Houston.
A resilient and flexible bond
Your usual common hydrogel will be very fragile, inflexible, and barely adhesive.
Zhao states that, “They’re often used as degradable biomaterials at the current stage. If you want to make an electronic device out of hydrogels, you need to think of long-term stability of the hydrogels and interfaces.”
To get over these hurdles, Zhao’s group thought of a creation method for a strong hydrogel. That method was combining water with trace amounts of selected biopolymers. When combined, a soft, flexible substance with a stiffness similar to that of human soft tissues was created. The group also concocted a way of strongly fusing the substance to different kinds of nonporous exteriors.
In the new experiment, the team applied their methods to show some of the hydrogel’s possible uses, including embodying a titanium wire to shape a straightforward, stretchable channel. In various trials, they extended the typified wire different times and doucmented that it kept up consistent electrical conductivity.
Zhao additionally made a variety of LED lights inserted in a sheet of hydrogel. At the point when appended to diverse districts of the body, the cluster kept working, notwithstanding when extended crosswise over very deformable areas like the knee and elbow.
An all-purpose matrix
In the end, the MIT team attached different types of electronic equipment to a sheet of hydrogel to create what they call a “smart wound dressing.” This dressing is comprised almost entirely of normally spaced temperature detectors and small drug canals. On top of that, Zhao’s team also created different paths for the meds to travel throughout the hydrogel. They did this by either placing patterned tubes into the hydrogel or drilling small holes into the matrix. They then put the dressing over different spots on the body and discovered that even when completely stretched, the dressing was able to keep track of skin temperature and was even able to release the meds in accordance with the sensor readings.
Yuk believes that the technology will be quickly utilized as a flexible and readily available remedy for burns and other various skin problems.
According to Yuk, “It’s a very versatile matrix. 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.”
Zhao strives to dig deeper and sees hydrogel as becoming the quintessential biocompatible vehicle for releasing technology into the body. Right now, he is looking into the potential for hydrogen to carry glucose sensors along with brain probes. Typical implanted glucose sensors trigger a foreign-body reaction from the immune system.
Once this happens, the sensors are covered with highly dense fibers, which leads to a constant need to replace them. While it is true that some other hydrogels have been utilized to cover glucose sensors and ensure that the immune response doesn’t happen, those hydrogels are weak and easily disconnect with movement. Zhao has assured us that his group is creating a hydrogel-sensor system that will be strong and in working shape for long periods. He also suggested that a likewise case could be presented for the brain probes.
“The brain is a bowl of Jell-O,” remarks Zhao. “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.
The research and studies mentioned above were made possible due to funding, in part, by the Office of Naval Research, the MIT Institute for Soldier Nanotechnologies, and the National Science Foundation.