Next-generation sutures are being developed to close wounds, detect inflammation, and deliver therapeutic drugs, further raising the bar in surgical recovery.
Engineers at the Massachusetts Institute of Technology (MIT) have created bioderived sutures to reduce patient discomfort and complications after surgery.
These smart sutures could help patients heal after bowel resection or other types of surgery.
The MIT researchers used pig tissue to create sutures that can carry sensors, drugs or cells and could also be adapted to heal wounds or surgical incisions elsewhere in the body.
Their work draws inspiration from catgut sutures that utilise collagen from cows, sheep and goats to form strong, naturally dissolving knots within around 90 days.
Former MIT postdocs Jung Seung Lee and Hyunjoon Kim are the lead authors of the paper published in Matter.
Giovanni Traverso is an associate professor of mechanical engineering at MIT, a gastroenterologist at Brigham and Women’s Hospital and the study's senior author.
Building on the concept of catgut, Traverso and his collaborators aimed to develop a tissue-derived suture material with enhanced properties such as toughness, absorbability and the advanced functionalities of sensing and drug delivery.
Such sutures could prove especially valuable for patients with Crohn’s disease, necessitating intestinal section removal due to scarring or inflammation-induced blockages.
The resealing of the remaining intestine ends following a procedure like this demands a secure seal to prevent hazardous leaks.
To mitigate this risk, the MIT team conceived the suture design that anchors the tissue and detects inflammation – a critical sign that the healed intestines are not recovering as expected.
The researchers crafted their innovative sutures from pig tissue, employing a ‘decellularisation’ process involving detergents to reduce the likelihood of triggering inflammation in the host tissue.
This process leaves a cell-free material called De-gut, encompassing structural proteins such as collagen and other biomolecules in the extracellular matrix around cells.
The team assessed its tensile strength after dehydrating and twisting the tissue into strands.
The results indicated comparable strength to commercially available catgut sutures, with the benefit of inducing significantly lower immune responses in surrounding tissue than traditional catgut.
Lee said: ‘Decellularised tissues have found extensive use in regenerative medicine due to their remarkable biofunctionality. We now propose an innovative platform for sensing and delivery using decellularised tissue that will unlock new applications for tissue-derived materials.’
The researchers progressed to enhance the suture material further by coating it with a hydrogel layer. Various cargo types could be embedded within this hydrogel, including microscopic particles capable of sensing inflammation, diverse drug compounds and even living cells.
The team designed microparticles coated with peptides released by inflammation-associated enzymes called MMPs for sensing.
These peptides can be detected through a simple urine test. Additionally, the researchers demonstrated the potential to carry drugs like dexamethasone and adalimumab—used for treating inflammatory bowel disease – via microparticles crafted from FDA-approved polymers like PLGA and PLA.
This method controls the drug release rate and can be adapted for other drug types like antibiotics or chemotherapy.
The versatility of these intelligent sutures extends to delivering therapeutic cells such as stem cells.
In exploring this application, the researchers incorporated stem cells engineered to express a fluorescent marker into the sutures, observing their viability for at least seven days after implantation in mice.
These cells could also produce vascular endothelial growth factor (VEGF), stimulating blood cell growth.
The team is now focused on comprehensively testing each potential application and scaling up suture manufacturing. They are also eager to investigate the feasibility of utilising these sutures in body regions beyond the gastrointestinal tract.
MIT engineers have designed tissue-derived smart sutures, pictured here, that can not only hold the tissue in place but also detect inflammation and release drugs. The sutures are coated with hydrogels that can be embedded with sensors, drugs, or cells that release therapeutic molecules. Image courtesy of the researchers
