A wound-healing gel inspired by slugs

Where sutures and stitches fail, doctors are turning to the restorative slime of gastropods.

While bandages protect wounds, cuts and scrapes, there's no equivalent to help internal wounds in the same way. To answer this shortcoming, engineers at the Wyss Institute of Harvard University are perfecting a new super-strong hydrogel adhesive inspired by the glue secreted by a common slug. The gel hopes to be an alternative to placing stitches, staples, and clips inside the body. 

It is a surgical adhesive that can adhere to wet and dynamic surfaces inside the body, including the heart, lung, tendons, cartilage, and bone. Paired with a novel tough hydrogel, it can undergo huge amounts of deformation, stretching out up to 20 times its original length, without breaking.

The researchers observed the way certain gastropod species can naturally change the composition of slime they give off to suit different situations. For instance, when it is threatened by a predator, the Dusky Arion slug modifies its mucus on a molecular level. It becomes incredibly sticky, acting as a kind of trail trap. In this state, the slime is adherent, durable and flexible all at once. Scientists analysed this reaction and now a surgical gel is being produced that will help wounds inside the body heal without the need for invasive stitches.

The material itself is a hybrid of two different polymers: a seaweed extract called alginate that is used to thicken food products and polyacrylamide, which is the chief material in soft contact lenses. When these relatively weak polymers become entangled with each other, they create an atomic network that is immensely tough, yet supple for a gel that is 90 percent water.

This nature-based innovation has a number of potential applications for the medical world, either as a patch that can be used to plug damaged tissues or as an injectable solution for deeper injuries. It can also be used to fix medical devices to their target organs, such as an actuator to support heart function or a sensor that feeds important health data. While the current iteration of the wound gel is designed to be permanent until manually removed, it could be made to biodegrade over time as the body recovers naturally.

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