Researchers at MIT have developed smart sutures with a hydrogel coating that contains sensing and drug delivery components, and could even be used to implant therapeutic cells. The sutures are made using pig tissues that have been decellularized with detergents to reduce the possibility that they could provoke an immune reaction. The surrounding hydrogel layer contains microparticles that can release peptides when enzymes involved in inflammation are present, and other microparticles that allow for controlled release of drugs. Another potential cargo is therapeutic stem cells that can assist with tissue repair. So far, the researchers have designed the sutures for use in intestinal repair surgeries, but are interested in widening their use.
As a staple in most surgical procedures, the humble suture has served us well for thousands of years. The ancient Romans used so-called ‘catgut’ sutures, that are derived from animal tissues. However, as a material that is present at the site of an incision or other surgical repair, sutures may represent a useful platform to give the body a helping hand in healing or otherwise fighting disease, and it may be time to move on from simple stitches as a purely mechanical intervention.
Recently, it appears that sutures are indeed getting smarter. Just last February, Medgadget reported on sutures that could kill bacteria and show up in CT scans, developed by a team at RMIT University in Australia. These latest sutures, developed at MIT, also have some neat tricks up their sleeve, with inflammation sensing and drug/cell delivery properties, but they also hark back to the ancient origins of sutures, with a catgut-style base material, derived from pig tissues (no cats were harmed during the production of this article).
“Decellularized tissues have been extensively used in regenerative medicine with their superb biofunctionality,” said Jung Seung Lee, a researcher involved in the study. “We now suggest a novel platform for performing sensing and delivery using decellularized tissue, which will open up new applications of tissue-derived materials.”
So far, the target application for the sutures is intestinal surgery, where two ends of the intestine are joined together, a potentially risky situation where leaks can cause serious complications for patients. In this context, a suture that can detect and respond to local inflammation would be useful. To deliver these advanced functionalities, the researchers coated their sutures in a hydrogel layer that can help to retain microparticles and cells on the surface of the suture.
To date, they have experimented with including microparticles that can release drugs such as steroid called dexamethasone and a monoclonal antibody, which are both used to treat inflammatory bowel disease. Another microparticle contains chemical linkers that are cleaved by inflammatory proteins, releasing a therapeutic cargo to help calm inflammation. Finally, the researchers have shown that the sutures can support living stem cells, highlighting the flexibility of this approach to deliver therapeutic modalities directly where they are needed.
Study in journal Matter: A Multifunctional decellularized-gut suture platform