Zebra Mussels May Be the Answer to a Biodegradable Glue
Published: Wednesday, January 26, 2022 12:00 pm
By: Annastasia Artzer
We're all familiar with "aquatic hitchhikers"—invasive, non-native animals that threaten our lakes and can cause environmental damage. They hitch onto the bottom of our boats, trailers, fishing gear, and equipment. Zebra mussels are one of the most devastating of these aquatic hitchhikers. Females can produce up to a million eggs per summer, growing up to two inches in length, and clogging intake pipes and filters. Not to mention the immense amount of phytoplankton and zooplankton they consume on a daily basis, starving the native populations of the waterway they infest.
The zebra mussel's ability to latch onto hard, smooth surfaces has puzzled scientists for years. Eli Sone, a professor in the Department of Materials Science & Engineering at the University of Toronto, has been working with his team to study zebra mussels and quagga mussels (another invasive species) for years, hoping to solve a range of problems.
"On one hand, these mussels are a problem in terms of what we call biofouling, so we're looking to design materials or coating to keep them from clogging water intake pipes, for example," said Sone.
"But on the other hand, if we understand why they stick so well, that could help us design things like non-toxic biodegradable glues, which could offer an alternative to internal stitches for surgery or localized drug delivery applications."
According to stopaquatichitchhikers.org, zebra mussels are native to the Caspian Sea region of Asia and arrived in the Great Lakes region in the 1980s in the ballast water of a ship. Since arriving in the Great Lakes they have spread to several major river systems, including the Ohio, Illinois, Mississippi, Mohawk, Hudson, Susquehanna, Tennessee, and Arkansas rivers.
Since zebra mussels are so small, measuring their ability to stick to various surfaces has been a challenge for Sone's team.
"The threads they use to attach themselves to surfaces are only a few millimeters long and as thin as a human hair," said University of Toronto Engineering alumnus Bryan James. "You can't put them in a traditional apparatus for testing tensile strength." James, who worked on the project as part of his undergraduate thesis, is a postdoctoral scholar at the Woods Hole Oceanographic Institution in Massachusetts.
The team's findings indicated that the mussels were able to adhere more strongly to glass than plastics, such as PVC. This was expected since glass is hydrophilic (water-attracting). PVC, on the other hand, is water-repellant and often applied to boat hulls to prevent biofouling.
After the mussel was detached from the item, the team examined the glue left behind using microscopes. "On some surfaces, we found that a thin protein residue was left behind after detachment," said Kenny Kimmins, a current Ph.D. student.
"This shows that the proteins at the interface interact very strongly with these surfaces even in wet conditions, which most synthetic adhesives can't do."
Sone and his team are continuing their research on new types of surfaces that can be used to prevent poisoning local ecosystems.
"Right now, people often use a chemical treatment to remove the mussels," said Sone. "That works, but it also kills everything else nearby. Having surfaces that are naturally hard for the mussels to stick to could offer a more environmentally sustainable option."
The team is also evaluating the glues produced by the mussels, in hopes that they will be able to imitate them in biomedical adhesives.
tags: Canada, Great Lakes
