Tendons See Potential New Hydrogel Repair Tech Inspired By Slug Slime

Athletes and workers who undergo regular physical stress will be the first to tell you the dangers of injuring your tendons. These tissues connect muscle to bone and are thus crucial to your everyday movements. As such, protecting your tendons from damage, or healing injuries to them in unfortunate cases, is of the utmost importance.

Unfortunately, healing injuries to these tissues are far from easy and hassle-free. For one, they require treatment for pretty long periods of time; this goes double for elderly patients, who also bear the highest risk of gaining injuries like these. It also doesn’t help that injuries of this type are also usually accompanied by inflammation and swelling, among other sources of pain.

Much like treatments for the rest of the body, tendons are also a focal point for medical researchers that aim to shorten the time it takes to heal, increase the effectiveness of healing, or sometimes both. One such team of researchers belonging to Harvard’s Wyss Institute for Biologically-Inspired Engineering may have found a peculiar source of inspiration for their potential new method for treating tendon injuries. Their research, odd as it may seem, involves slugs and is published in the journal Nature Biomedical Engineering.

The research team, which is led by Dr. David Mooney and includes first author Benjamin Freedman, took inspiration from the dusky arion slug (Arion fuscus, sometimes synonymous with Arion subfuscus), a slug which lives across northern Europe. A. fuscus lives across tne whole swath, while A. subfuscus is restricted to areas in northwestern Europe.

Inspired by the intrepid slugs, the team successfully made an adhesive gel years ago they called “Tough Gel Adhesives” (TGAs), with the paper describing it having been published in the journal Science.

Now, following up with their previous research, Mooney and team now made a hydrogel using the TGAs that are applicable to tendon repair. The new material, coined “Janus Tough Adhesives” (JTAs) and named after the Roman god with two faces, is now set to tackle tendon injuries with the help of its properties.

The JTAs are composed of two distinct surfaces, thus their special naming. One surface, which clings to the damaged surfaces of tendons in order to keep them together to facilitate healing, is made of a material called chitosan, a sugar derived from shellfish and similar shelled sea creatures.

The opposite side, however, does the exact opposite and is responsible for keeping the tendon gliding against neighboring tissue during movement, and thus also helps to ensure that mobility is restored as much as possible. This “smooth” side is made of just the bare hydrogel.

The JTAs were tested on both animal and human tissue via cadavers and were found to be capable of adhering to both. The team also incorporated corticosteroids, or drugs that help reduce inflammation and scar formation in wounds, into the hydrogel; they found that the JTAs treated with these drugs also helped reduce inflammation in knee tendons in rats.

“Importantly, when we applied JTAs to ruptured patellar tendons of rats, they remained in place over their three-week implantation and facilitated tendon healing,” Freedman stated to news source New Atlas. “They also reduced the formation of scars by 25 percent, compared to surgically repaired tendons that we didn’t treat with JTAs.”

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“JTAs with their combination of tissue-specific capabilities offer a new opportunity to overcome current insufficiencies in tendon regeneration across multiple types of injuries, and could help many patients regain more normal tendon functions and mobility,” said Mooney in a statement from a Wyss Institute news piece.

One of the next steps for the team would be testing on live human patients; luckily, all materials involved with the JTAs are already biocompatible. The team hopes that surgeons of the future will have a much easier time dealing with these types of injuries using their novel healing technology.

References

• Boettner, B. (2022, January 3). Towards more effective tendon repair with a multi-functional biomaterial. Wyss Institute. https://wyss.harvard.edu/news/towards-more-effective-tendon-repair-with-a-multi-functional-biomaterial/
• Freedman, B. R., Kuttler, A., Beckmann, N., Nam, S., Kent, D., Schuleit, M., Ramazani, F., Accart, N., Rock, A., Li, J., Kurz, M., Fisch, A., Ullrich, T., Hast, M. W., Tinguely, Y., Weber, E., & Mooney, D. J. (2022). Enhanced tendon healing by a tough hydrogel with an adhesive side and high drug-loading capacity. Nature Biomedical Engineering, 1–13. https://doi.org/10.1038/s41551-021-00810-0
• Irving, M. (2022, January 4). Slug-slime-inspired biomaterial speeds repair of injured tendons. New Atlas. https://newatlas.com/medical/janus-tough-adhesive-tendon-injury/
• Li, J., Celiz, A. D., Yang, J., Yang, Q., Wamala, I., Whyte, W., Seo, B. R., Vasilyev, N. V., Vlassak, J. J., Suo, Z., & Mooney, D. J. (2017). Tough adhesives for diverse wet surfaces. Science. https://doi.org/10.1126/science.aah6362
• Tough gel adhesives for wound healing. (2018, February 28). Wyss Institute. https://wyss.harvard.edu/technology/tough-gel-adhesives-for-wound-healing/