Stretchy Hydrogel "Band-Aid" Can Be Used On Bendy Joints

A sheet of the hydrogel is shown with electrical components embedded. Melanie Gonick/MIT
Ben Taub 08 Dec 2015, 23:24

Getting a cut, scrape or graze on the body’s bendy bits can be a frustrating experience, as Band-Aids just never seem to stay stuck on these joints. However, the recent invention of a novel ultra-stretchy gel could herald the beginning of a new age in wound healing, leading to the creation of superior dressings that are not only far stickier than anything that has come before, but can also incorporate sensors, medications, and a range of smart electronic components.

Publishing a report of their work in the journal Advanced Materials, the researchers from the Massachusetts Institute of Technology (MIT) explained that “animal bodies are mainly composed of hydrogels – polymer networks infiltrated with water.” Scientists have for some time sought to create synthetic substances that mimic these biological hydrogels, yet previous attempts to do so have tended to “suffer from the limitation of low mechanical robustness and low stretchablity,” thus rendering them disappointingly brittle.

However, by using a polymer (a large molecule consisting of many repeated subunits) called polyacrylamide, the team was able to develop a new hydrogel that is “robust, highly stretchable, biocompatible and capable of multiple novel functions.”

For instance, the substance remains firmly stuck in place even when adhered to bendy areas of the body such as knees and elbows. Furthermore, it can be used to house a variety of electrical components such as titanium wires, light-emitting diodes (LEDs), and electronic chips.

The researchers also demonstrated that drug-delivering channels and reservoirs could be incorporated into the fabric of the hydrogel. This opens the door to the creation of new “smart wound dressings,” with the ability to deliver drugs in response to certain biological stimuli such as changes in body temperature.

Crucially, the extreme strength and robustness of the substance ensures that its various components are able to remain firmly in place even as the gel itself is stretched and distorted. For instance, the researchers have provided details of the process by which electrical components can be stuck to the matrix of the hydrogel, by using silanized glass slides (adding silicon to make them more water resistant) as an intermediary interface between the two surfaces. Subsequently, the embedded items cannot be pulled apart from this matrix even when tugged with enough force to severely warp the shape of the gel itself.

“It’s a very versatile matrix,” explained study coauthor Hyunwoo Yuk in a statement. “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.”


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