Smart Sutures: A Novel Advancement in the Medical Field

Wednesday - June 21 2023, 12:39 UTC - 1 year ago

MIT engineers have designed “smart” sutures derived from animal tissue, similar to the “catgut” sutures first used by the ancient Romans, coated with hydrogels that can be embedded with sensors, drugs, or even cells that release therapeutic molecules. The sutures are designed to be tough and absorbable and contain structural proteins such as collagen relevant for their medicinal properties. The sutures have the potential to be used to heal wounds and surgery incisions in the body as well as help Crohn's Disease patients through its ability to detect inflammation in resealed intestines.

The bioderived “smart sutures” could help patients heal after bowel resection or other types of surgery.

Inspired by sutures developed thousands of years ago, MIT engineers have designed “smart” sutures that can not only hold tissue in place, but also detect inflammation and release drugs. The new sutures are derived from animal tissue, similar to the “catgut” sutures first used by the ancient Romans. In a modern twist, the MIT team coated the sutures with hydrogels that can be embedded with sensors, drugs, or even cells that release therapeutic molecules.

“What we have is a suture that is bioderived and modified with a hydrogel coating capable of being a reservoir for sensors for inflammation, or for drugs such as monoclonal antibodies to treat inflammation. Remarkably, the coating also has the capacity to retain cells that are viable for a prolonged period,” says Giovanni Traverso, an associate professor of mechanical engineering at MIT, a gastroenterologist at Brigham and Women’s Hospital, and the senior author of the study.

The researchers envision that these sutures could help patients with Crohn’s disease heal after surgery to remove part of the intestine. The sutures could also be adapted for use to heal wounds or surgical incisions elsewhere in the body, the researchers say.

Former MIT postdocs Jung Seung Lee and Hyunjoon Kim are the lead authors of the paper, which was recently published in the journal Matter.

Catgut sutures — which are made from strands of purified collagen from cows, sheep, or goats (but not cats) — form strong knots that naturally dissolve within about 90 days. Although synthetic absorbable sutures are also available, catgut is still used in many types of surgery.

Traverso and his colleagues wanted to see if they could build on this type of tissue-derived suture to create a material that would be tough and absorbable, and have advanced functions such as sensing and drug delivery. Such sutures could be particularly useful for Crohn’s disease patients who need to have a part of the intestine removed due to blockage from excessive scarring or inflammation. This procedure requires resealing the two ends left behind after one section of the intestine is removed. If that seal doesn’t hold tightly, it can lead to leaks that are dangerous for the patient.

To help reduce this risk, the MIT team wanted to design a suture that could not only hold the tissue in place but also detect inflammation, an early warning sign that the resealed intestines are not healing properly.

The researchers created their new sutures from pig tissue, which they “decellularized” using detergents, to reduce the chances of inducing inflammation in the host tissue. This process leaves behind a cell-free material that the researchers call “De-gut,” which contains structural proteins such as collagen, as well as other biomolecules found in the extracellular matrix that surrounds cells.

After dehydrating the tissue and twisting it into strands, the researchers evaluated its tensile strength — a measure of how much stretching it can withstand before breaking — and found that it was comparable to commercially available synthetic absorbable sutures.