MIT researchers have developed smart hydrogel-coated sutures that contain sensing and drug delivery components and can even be used to implant therapeutic cells. The sutures are made using pig tissues that have been decellularized with detergents to reduce the possibility of them provoking 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 controlled drug release. Another potential cargo is therapeutic stem cells, which can aid in tissue repair. So far, researchers have designed the sutures for use in bowel repair surgeries, but are interested in expanding their use.
As a staple in most surgical procedures, the humble thread has served us well for thousands of years. The ancient Romans used so-called catgut threads, which are derived from animal tissues. However, as a material present at the site of an incision or other surgical repair, sutures can provide a useful platform to help the body heal or otherwise fight disease, and it may be time to move on from simple stitches as a purely mechanical intervention.
Threads really seem to be getting smarter lately. Just last February, Medgadget report stitches that can kill bacteria and show up on CT scans, developed by a team at RMIT University in Australia. These latest MIT-developed sutures also have some clever tricks up their sleeve, with inflammation-sensing and drug/cell delivery properties, but also remind us of the ancient origins of sutures, with a base material in catgut derived from pig tissue (no cats were harmed during the production of this article).
“Decellularized tissues are widely used in regenerative medicine with their superior biofunctionality,” said Jung Seung Lee, a researcher involved in the study. “We now offer a new platform for performing sensing and delivery using decellularized tissue, which will open up new applications of tissue-derived materials.”
For now, the sutures’ target application is intestinal surgery, where two ends of the intestine are joined, a potentially risky situation where leakage can cause serious complications for patients. In this context, a thread that can detect and respond to local inflammation would be useful. To provide these advanced features, the researchers coated their sutures with a hydrogel layer that can help trap microparticles and cells on the surface of the sutures.
To date, they have experimented with incorporating microparticles that can release drugs such as a steroid called dexamethasone and a monoclonal antibody that are used to treat inflammatory bowel disease. Another microparticle contains chemical linkers that are cleaved by inflammatory proteins, releasing a therapeutic cargo that helps calm inflammation. Finally, the researchers showed that the sutures can support living stem cells, highlighting the versatility of this approach to deliver therapeutic modalities directly to where they are needed.
Research in a journal matter: A multifunctional decellularized platform for intestinal suturing
Flashbacks: New 3-D ‘Smart’ Threads for Wireless Biological Data Collection; Antibacterial smart sutures visible on CT scan;
Through: MIT
