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As anyone who has ever tried to put a BandAid on wet skin can attest, it is very difficult to get adhesives to stick to anything damp. This is a particular problem for doctors and surgeons, who sometimes use adhesives to hold wounds closed. Even when surgical adhesives are attached to dry skin, they can be inflexible, leading to the wound opening again. As many adhesives are also toxic to cells, they are not generally useful for deeper injuries. Now, a team of researchers from the Wyss Institute for Biologically Inspired Engineering and the Harvard John A. Paulson School of Engineering and Applied Sciences may have an answer. The team has created a non-toxic adhesive that will bind strongly to tissues even when they’re wet.

In the past, many researchers have gained inspiration from the natural world – even using squid ring teeth to create a self-healing bioplastic. To create their bio-glue, the Harvard researchers turned to an unlikely source – the Dusky Arion slug (Arion subfuscus), which when threatened secretes a mucus that glues the slug in place – making it difficult for a predator to pry it lose and make off with it. The slug mucus inspired the researchers to create a double-layered hydrogel, which not only bonds to biological tissues but can also dissipate energy, enabling it to bend and stretch rather than break loose. This means the adhesive can be used to seal wounds inside the body, even on organs such as the heart, which are constantly being stretched. Says Wyss Founding Director Donald Ingber, “Nature has frequently already found elegant solutions to common problems; it’s a matter of knowing where to look and recognizing a good idea when you see one.”

The researchers suggest that the hydrogel can be cut to different sizes and applied as a patch directly to tissue surfaces, or used as an injectable solution for deeper injuries. It can also be used to attach medical devices directly to tissues, or combined with pharmaceuticals to create a new way to deliver medications more precisely. Similar hydrogels have recently been developed which can carry embedded electronics. What other uses might there be for a surgical adhesive that can be used internally?