‘Smart’ sutures that deliver drugs and detect inflammation

2023-05-17 12:50:06

A team of engineers from the Massachusetts Institute of Technology ((MIT) has taken inspiration from ancient suture techniques to design ‘intelligent’ methods. These can not only hold tissue in place, but also detect inflammation and release drugs.

The new sutures are derived from animal tissue and are similar to the sutures catgut First used by the ancient Romans. In a novel twist, the MIT team coated the spots with hydrogels into which sensors, drugs or even cells that release therapeutic molecules.

“What we have is a bioderived and modified suture with a hydrogel coating capable of being a reservoir for inflammation sensors, or for drugs as monoclonal antibodies to treat inflammation. Surprisingly, the coating also has the ability to retain viable cells for a prolonged period,” he says. John TraversoMIT associate professor of mechanical engineering and lead author of the study.

We have achieved a bioderived and modified suture with a hydrogel coating capable of being a reservoir for inflammation sensors and drugs

Giovanni Traverso, principal author of the study

Jung Seung Lee y Hyunjoon Kimformer MIT postdoctoral students, are the lead authors of the paper, which is published in the journal Matter. These researchers envision that the sutures could also be adapted to treat wounds or surgical incisions in other parts of the body.

Strands of purified cow, sheep or goat collagen

Catgut sutures, made with strands of purified cow, sheep, or goat collagen, form strong knots that dissolve naturally in about 90 days. Although absorbable synthetic techniques also exist, catgut is still used in many types of surgery.

Traverso and his colleagues wanted to see if they could build on this ancient Roman weaving-derived method to create a material that was resistant and absorbablewhich also had advanced functions such as drug detection and administration.

These sutures could be especially useful for crohn’s patients who have to remove a part of the intestine due to an obstruction due to excessive scarring or inflammation. This procedure requires resealing the two ends that remain after the removal of a section of intestine. If that seal is not airtight, dangerous leaks for the patient can occur.

They could be beneficial for Crohn’s patients who have to remove part of the intestine, due to an obstruction due to excessive scarring or inflammation

To help reduce this risk, the MIT team wanted to design a technique that could not only keep the tissue in place, but also detect inflammationan early warning sign that resected intestines are not healing properly.

The researchers created their new sutures from porcine tissue, which they ‘decellularized’ with detergents, to reduce the chances of inflammation in the host tissue. This process leaves behind a cell-free material. Researchers have called it De-gut And contains structural proteins such as collagen, as well as other biomolecules found in the extracellular matrix that surrounds cells.

After dehydrating and threading the tissue, they evaluated its tensile strength -which measures the stretch that the material can withstand before breaking- and they discovered that it was comparable to sutures catgut available on the market. They also demonstrated that healing with De-gut induces a much lower immune response from the surrounding tissue.

“‘Decellularized’ tissues have been widely used in regenerative medicine for their excellent biofunctionality“, says Lee. “We now suggest a novel platform to carry out detection and delivery with these same tissues, which will open up new applications of derived materials.”

Peptide-coated microparticles

The authors set out to endow the material with additional functions. To do this, they covered the sutures with a layer of hydrogel. Within this, they can incorporate various types of components: microparticles capable of detecting inflammation, various drug molecules or living cells.

For the sensor application, the researchers engineered peptide-coated microparticles that are released when inflammation-associated enzymes called MMP. Those peptides can be detected by a simple urinalysis.

They also used the hydrogel coating to transport drugs used in inflammatory bowel disease, including a steroid called dexamethasone and a monoclonal antibody called adalimumab. These drugs are delivered via microparticles made of polymers, which are used to control the rate of release. According to the researchers, this method could also be adapted to administer other types of drugs, such as antibiotics or chemotherapy.

This method could also be adapted to administer other types of drugs, such as antibiotics or chemotherapy

These sutures could also be used to release therapeutic cells. The MIT team integrated stem cells engineered to express a fluorescent marker and found that they remained viable for at least seven days when implanted in mice. The cells were also able to produce vascular endothelial growth factorwhich stimulates the growth of blood cells.

The team plans to continue testing each of these possible applications and expand the process. suture manufacturing. They also hope to explore the possibility of using the sutures in parts of the body other than the gastrointestinal tract.

“The decellularized intestinal suture developed by the MIT team is an exciting platform for detecting and managing a wide range of therapies, including small molecules, biologics, and living cells. The team has done a great job demonstrating solid the versatility of this platform“, says Omid Veisehan associate professor of bioengineering at Rice University, who was not involved in the study.

Reference:

Traverso, G. et al. “A multifunctional decellularized gut suture platform” Matter (mayo, 2023)

Rights: Creative Commons.