Inspiration from Worms and Mussels - A Sutureless Way to Do Surgery

Healing from surgery can be complicated by using sutures in particular parts of our bodies. Depending on the type of material (silk or polymer-based), the immune system can have a reaction, prolonging healing times to as long as 4 months! 

So what is a possible alternative that can be easily applied to sensitive tissue and maintain structural integrity long enough for healing? One clever organism that bioengineers are currently studying is the sandcastle worm or Phragmatopoma californica.


 

By Fred Hayes for the University of Utah [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

Scott Creek, Santa Cruz Co., CA; 17 Mar 2008

Sandworms are typically shy creatures, coming out only to catch microorganisms and grain particles. Their tubules can be found along Baja California and Mexico.

Professor of Bioengineering Russell Stewart from the University of California Santa Barbara is currently studying waterproof adhesives that sandcastle worms (and caddisflies) use to create their elaborate constructions. In his research, he has determined that the forces of attraction are electrostatic (oppositely charged ions attracting each other) with some cross-linking between catechol and DOPA polymers.

Inspired by the worm's ability to create an adhesive that works in water, medical doctor Nora Lang and bioengineers Maria Pereira and Jeffrey Karp at Harvard Medical School teamed up with other scientists to create an adhesive that works in vivo in repairing tiny defects in sensitive tissue.

 Exposure of hydrophobic light-activated adhesive polymer (HLAA) to UV light creates crosslinking

(image from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4157752/)

Using a polymer of glycerol and sebacic acid, they exposed the molecules to UV light and created crosslinks. This resulted in a highly flexible material that could be gently applied to very small tears in a carotid artery:

In this carotid artery, a hole was created and then sealed with HLAA polymer. After 24 hours, the seal remained intact. 

(from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4157752/)

With its recently tested potential, light-activated liquid polymers may have a place on the surgeon's tray in place of sutures.

Articles and Resources of Interest:

*A Blood-Resistant Surgical Glue for Minimally Invasive Repair of Vessels and Heart Defects; by N. Lang, M.J. Pereira, Y. Lee, I. Friehs, N.V. Vasilyev, E.N. Feins, K. Ablasser, E.D. O'Cearbhaill, C. Xu, A. Fabozzo, R. Padera, S. Wasserman, F. Freudenthal, L.S. Ferreira, R. Langer, J.M. Karp, and P.J. del Nido

*Letting Bio-Inspired Solutions Evolve : Q &A with Jeff Karp