Slug slime inspires new kind of surgical glue

Scientists have developed an experimental surgical glue inspired by the mucus secreted by slugs that could offer an alternative to sutures and staples for closing wounds.

While some medical glues already exist, they often adhere weakly, are not particularly flexible and frequently cannot be used in very wet conditions.

To get around those problems, a group of scientists from Harvard and other research centres decided to learn from slugs, which - as well as making slime to glide on - can produce extremely adhesive mucus as a defence mechanism.

The slugs' trick is to generate a substance that not only forms strong bonds on wet surfaces but also has a matrix that dissipates energy at the point of adhesion, making it highly flexible.

The man-made version of this tough adhesive is based on the same principles and in a series of experiments reported in the journal Science on Thursday it was shown to adhere strongly to pig skin, cartilage, tissue and organs. It also proved non-toxic to human cells.

In one test the new glue was used to close a wound in a blood-covered pig's heart and successfully maintained a leak-free seal after the heart was inflated and deflated tens of thousands of times.

In another case it was applied to a laceration in a rat's liver and performed just as well as a haemostat, a surgical tool often used in operations to control bleeding.

"There are a variety of potential uses and in some settings this could replace sutures and staples, which can cause damage and be difficult to place in certain situations," said researcher David Mooney, professor of bioengineering at Harvard.

Mooney and colleagues envisage the new adhesive will be made in sheets and cut to size, although they have also developed an injected version for closing deep wounds. The injection would be hardened using ultraviolet light, like dental fillings.

It is not the first time that scientists have taken inspiration from nature to devise a better medical adhesive.

Four years ago, another research group developed a glue inspired by the underwater sticking properties of mussels, but Mooney thinks slugs win hands-down in terms of stickiness and flexibility.

The scientists are applying for patents, although it will require a commercial company to then license the technology and take it into the next phase of human clinical trials.