MIT engineers have crafted “intelligent” sutures, derived from animal tissue, that do more than just hold tissue together; they can also detect inflammation and administer drugs. This is achieved by coating the sutures with hydrogels capable of housing sensors, drugs, or cells to emit healing molecules.
These bio-derived intelligent sutures may assist patients’ recovery post procedures like bowel resection or other surgical treatments.
Taking a cue from sutures formulated thousands of years back, the engineers at MIT developed intelligent sutures that besides holding the tissue together can identify inflammation and deliver drugs.
Similar to the “catgut” sutures introduced by the ancient Romans, these sutures also use animal tissue. However, the MIT team modernized the concept by incorporating hydrogels that can be filled with sensors, drugs, or cells to release therapeutic molecules.
Giovanni Traverso, an associate professor of mechanical engineering at MIT and a gastroenterologist at Brigham and Women’s Hospital, explains, “Our suture is bio-derived, and has been adapted with a hydrogel coating, which can house sensors for inflammation or drugs, such as monoclonal antibodies for treating inflammation. Impressively, the coating can also retain viable cells for an extended duration.”
The research team believes that these sutures could be particularly beneficial for patients with Crohn’s disease recuperating post the surgical removal of a section of the intestine. These sutures could also be repurposed to heal wounds or surgical cuts elsewhere in the body.
The study, recently published in the journal Matter, is credited to former MIT postdocs Jung Seung Lee and Hyunjoon Kim as lead authors.
On the Catgut Connection
Catgut sutures, crafted from purified collagen strands from cows, sheep, or goats (not cats), form sturdy knots that naturally dissolve over approximately 90 days. Although synthetic absorbable sutures are an option, catgut continues to be the preferred choice in numerous surgical procedures.
The idea behind Traverso and his team’s research was to further this tissue-derived suture model to design a robust, absorbable material that could perform advanced tasks such as sensing and drug delivery.
Such sutures would be especially beneficial for Crohn’s disease patients who need to have a part of the intestine removed due to obstructions from excessive scarring or inflammation. This procedure involves resealing the two ends left after a section of the intestine is removed. A weak seal could result in dangerous leaks for the patient.
To mitigate this risk, the MIT team aimed to develop a suture that not only holds the tissue together but also alerts to inflammation, an early indication that the resealed intestines are not healing correctly.
The team used pig tissue to make their new sutures, which they decellularized using detergents to minimize the risk of inflammation in the host tissue. This process produces a cell-free material known as “De-gut,” which comprises structural proteins like collagen and other biomolecules found in the extracellular matrix that surrounds cells.
After the tissue was dehydrated and twisted into strands, its tensile strength was comparable to commercially available catgut sutures. The team also observed that the De-gut sutures prompted a much weaker immune response than traditional catgut.
Lee adds, “Decellularized tissues, due to their excellent biofunctionality, are frequently employed in regenerative medicine. We propose a new platform for sensing and delivery using decellularized tissue, which will pave the way for new applications of tissue-derived materials.”
The researchers then set their sights on enhancing the suture material with additional functionalities. This involved coating the sutures with a hydrogel layer, which could accommodate a variety of cargo, including microparticles that sense inflammation, different drug molecules, or living cells.
For sensor application, the team designed microparticles covered with peptides that are released when tissue presents inflammation-associated enzymes, known as MMPs. These peptides can be detected through a simple urine test.
Additionally, the researchers demonstrated that the hydrogel coating could transport drugs used to treat inflammatory bowel disease, such as a steroid known as dexamethasone and a monoclonal antibody called adalimumab. The microparticles transporting these drugs are made from FDA-approved polymers like PLGA and PLA, which regulate the drug release rate. The team also believes this approach could be modified to deliver other kinds of drugs, such as antibiotics or chemotherapy drugs.
These intelligent sutures can also deliver therapeutic cells like stem cells. The team experimented with this idea by embedding sutures with stem cells engineered to express a fluorescent marker. They found that the cells remained viable for at least a week when implanted in mice and could produce vascular endothelial growth factor (VEGF), a growth factor that stimulates blood cell growth.
The researchers are now focusing on further testing of these potential applications and scaling up the production process for the sutures. They are also considering the possibility of using the sutures in parts of the body other than the gastrointestinal tract.
Omid Veiseh, an associate professor of bioengineering at Rice University, who was not involved in the study, says, “The decellularized gut suture developed by the MIT team is an exciting platform for sensing and delivering a wide range of therapeutics, including small molecules, biologics, and living cells. The team has done a great job robustly demonstrating the versatility of this platform.”
The study, “A multifunctional decellularized gut suture platform” by Jung Seung Lee, Hyunjoon Kim, Gwennyth Carroll, Gary W. Liu, Ameya R. Kirtane, Alison Hayward, Adam Wentworth, Aaron Lopes, Joy Collins, Siid Tamang, Keiko Ishida, Kaitlyn Hess, Junwei Li, Sufeng Zhang and Giovanni Traverso, was published on May 16, 2023, in the Matter journal.
Other contributors to the paper include Gwennyth Carroll, Gary Liu, Ameya Kirtane, Alison Hayward, Adam Wentworth, Aaron Lopes, Joy Collins, Siid Tamang, Keiko Ishida, Kaitlyn Hess, Junwei Li, and Sufeng Zhang.
The Leona M. and Harry B. Helmsley Charitable Trust, the MIT Department of Mechanical Engineering, the National Research Foundation of Korea, and a National Institute of Diabetes and Digestive and Kidney Disease Ruth L. Kirschstein NRSA Fellowship funded the research.
Frequently Asked Questions (FAQs) about Smart Sutures
What are “smart” sutures?
“Smart” sutures are a new type of suture developed by MIT engineers. These sutures, derived from animal tissue, are coated with hydrogels that can hold sensors, drugs, or cells. These sutures can perform tasks beyond just holding tissue together, such as detecting inflammation and administering drugs.
Who developed these “smart” sutures?
The “smart” sutures were developed by a team of engineers from the Massachusetts Institute of Technology (MIT), led by Associate Professor of Mechanical Engineering Giovanni Traverso.
What is the primary purpose of these “smart” sutures?
The primary purpose of these “smart” sutures is to hold tissue together following surgery. However, they are also designed to detect inflammation and release drugs, providing a more versatile healing tool. This could be particularly beneficial for patients with Crohn’s disease recovering from surgery.
How do these “smart” sutures work?
These sutures are coated with a layer of hydrogel which can be embedded with various types of cargo — microparticles that sense inflammation, different drug molecules, or living cells. When inflammation is detected, it can trigger the release of drugs from the suture to help combat the inflammation.
What is the potential future application of these “smart” sutures?
Beyond assisting with the healing process post-surgery, these “smart” sutures could be used to heal wounds or surgical incisions anywhere in the body. The research team is also considering the possibility of using the sutures to deliver therapeutic cells like stem cells.
Who funded the research for these “smart” sutures?
The research was funded by several entities, including the Leona M. and Harry B. Helmsley Charitable Trust, the MIT Department of Mechanical Engineering, the National Research Foundation of Korea, and a National Institute of Diabetes and Digestive and Kidney Disease Ruth L. Kirschstein NRSA Fellowship.
More about Smart Sutures
- MIT News
- Giovanni Traverso’s Profile at MIT
- Information about Crohn’s Disease
- Journal “Matter” Homepage
- National Institute of Diabetes and Digestive and Kidney Disease
- Leona M. and Harry B. Helmsley Charitable Trust