Researchers from the Wyss Institute for Biologically Inspired Engineering and the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new type of surgical adhesive that could be safely used for a variety of applications in the future.
Co-first author Jianyu Li settled with the idea of mimicking slug slime after poring over materials covering the common Dusky Arion's (Arion subfuscus) defense mechanism in which the slug produces a lot of mucus that glues it in place when threatened by a predator.
How Tough Is The Slug-Inspired Glue?
According to the researchers, the slug mucus-inspired glue forms a very strong bond to biological tissue — wet or dry — and can maintain its stability even when inflated, deflated, or stretched repeatedly. It's also free of any toxic substances present in commercially available strong adhesives, which is really one of its best features.
The fact that the adhesive can be applied to wet surfaces is a plus in itself since current surgical adhesives don't really work well when used on bleeding wounds. It is also not flexible enough to move with the skin, which makes it prone to breaking with enough stress.
The newly developed adhesive, on the other hand, is composed of a hydrogel layer and a liquid adhesive layer with positively charged polymers that allow it to bond to the tissue chemically.
"Most prior material designs have focused only on the interface between the tissue and the adhesive. Our adhesive is able to dissipate energy through its matrix layer, which enables it to deform much more before it breaks," Li explains.
Li also notes that, unlike current surgical adhesives that take effect immediately, surgeons would have about 10 seconds to put the adhesive into the right spot before it bonds. After that, the hydrogel layer will be able to accommodate stress from the tissue.
To test this, the research team used the slug adhesive on wet and dry pig organs, and even mimicked a beating heart with a mechanical device after covering a hole on a pig heart. The adhesive moved with the tissue while effectively keeping the glued surfaces together.
The adhesive's performance even prompted study co-author Dr. Nikolay Vasilyev to say that the flexible adhesive could potentially be used in the hearts of growing children with cardiovascular disease. Dr. Vasilyev is an assistant professor of surgery and research scientist at the Boston Children's Hospital.
Slug Inspiration
The new adhesive's current version is focused on improving its binding ability, which proved very successful after several tests, but the researchers say it could be made with biodegradable materials later on so it would dissolve after use, just like currently available surgical glue.
It may take a while before the slug-inspired adhesive becomes available for surgical applications in humans, but experts are positive that the new adhesive presents important implications for the medical field.
"In human patients, safety is paramount so there will be long term studies to have a high level of confidence in safety," corresponding author Dave Mooney said.
Just in case anyone was wondering, Mooney also clarified that his research team's adhesive is only slug-inspired so no slugs were or will ever be harmed in its development.
