New studies may bring slug-made glues closer to use in medicine

Thursday, April 11, 2019 

In two studies presented on Monday at the annual meeting of the American Society for Biochemistry and Molecular Biology in Orlando, Florida in the United States, scientists have disclosed new steps toward using natural adhesives made by the dusky Arion slug (Arion subfuscus) in medical applications such as in closing skin wounds and reducing scarring.

An Arion land slug in Canada.
Image: Ryan Hodnett.

When threatened, the dusky Arion slug secretes an unusual glue, making itself a difficult target for predators. This glue remains both sticky and flexible and works even when the surface the slug is on is wet. Previous studies have shown that, unlike many artificial adhesives, Arion slug glue is non-toxic to mammalian tissue.

Scientist Rebecca Falconer, an Ithaca College undergraduate who led one of the two studies, said "Typical sutures like staples and stitches often lead to scarring and create holes in the skin that could increase the chance of infection after surgery [...] Understanding the roles of adhesive proteins in the slug glue would aid in the creation of a medical adhesive that can move and stretch yet still retain its strength and adhesiveness."

In her set of experiments, Falconer observed eleven proteins found only in slug glue and used DNA recombination to produce usable amounts of each of these proteins. Specifically, she produced complementary DNA sequences (cDNA) for each protein, which are stretches of DNA with all the pieces not necessary for producing the protein removed. She then spliced these into circular DNA sequences called plasmids, which she inserted into bacteria, whose natural cellular machinery began to produce the proteins in quantity. She then analyzed the three-dimensional structures that the protein molecules form with each other and with other substances that make them work.

Christopher Gallego-Lazo, also an Ithaca undergrad, evaluated glue from the dusky Arion slug by focusing on the chemical bonds within the glue and the way they affect the glue's deformability. Gallego-Lazo found that slight changes in these chemical bonds could alter the strength of the slug glue.

Gallego-Lazo said, "Few studies on biological adhesives have identified the exact nature of the bonds holding the glue together [...] This knowledge can guide the development of an organic synthetic adhesive that would reduce the risk of infection and scarring compared to stitches and staples and could be applied rapidly and simply."

Falconer and Gallego-Lazo both performed their research in the laboratory of Dr. Andrew Smith.

Sources

• "Slug slime may be better than stitches: The natural 'glue' is stronger and leaves less scarring, study suggests" — Daily Mail, April 8, 2019
• Ithaca College. "Slug glue reveals clues for making better medical adhesives" — Eurekalert, April 8, 2019
• Rebecca Falconer and Andrew Smith. "Expression, Purification and Analysis of Recombinant Proteins Responsible for the Functional Properties of a Tough Biological Glue (abstract)" — Experimental Biology 2019, April 8, 2019 (date of access)
• Christopher Gallego-Lazo and Andrew Smith. "Characterizing the Role of Metal Ion Interactions in the Elasticity and Strength of Slug Glue: Steps Toward a Novel Medical Adhesive (abstract)" — Experimental Biology 2019, April 8, 2019 (date of access)
• "cDNA (Complementary DNA)" — Humangenes.org, April 8, 2019 (date of access)
• Rae Ellen Bichell. "Slug Slime Inspires Scientists to Invent Sticky Surgical Glue" — NPR, July 27, 2017