Researchers create ‘plaster’ to seal internal wounds

© Empa

An innovative patch to seal internal wounds and prevent dangerous leakages has been developed by researchers in Switzerland.

A team of researchers from Empa have created a polymer patch for the intestine that can be used to stably bond and seal internal injuries.

Instances such as a burst appendix or intestinal volvulus require immediate treatment from surgeons, but such operations do come with serious risks attached. Everything that is transported through the gastrointestinal tract to the outside world belongs there, so it is essential that nothing transfers to the abdominal cavity. Highly acidic digestive juices and germ-laden food residues could trigger peritonitis or even fatal sepsis.

To go beyond the capabilities of a needle and thread, Empa researchers have developed a patch that seals two sutured pieces of intestine to prevent leaks. The concept of sealing sutured tissue with a plaster is already in practice in operating theatres but, after the first of these products turned out to be poorly tolerated or even toxic, these plasters are currently made of biodegradable proteins. The researchers say the problem with using protein patches is that clinical success is not always optimal and varies depending on the tissue used. This, they say, is because the protein patches are primarily intended to support the healing process and dissolve too fast when in contact with digestive juices, loosening their strength.

Empa researcher Inge Herrmann, who is also Professor for nanoparticulate systems at ETH Zurich, said: “Leaks after abdominal surgery are still one of the most feared complications today.”

The team, led by Herrmann and Alexandre Anthis from Empa’s Particles-Biology Interactions lab in St Gallen, joined forces with Andrea Schlegel, a surgeon at Queen Elizabeth University Hospital in Birmingham, to search for a material that could reliably seal intestinal injuries and surgical wounds.

The team found a synthetic composite material consisting of four acrylic substances that, together, form a chemically stable hydrogel. Additionally, the patch actively cross-links with the intestinal tissue until no more fluid can pass through. The researchers have already successfully patented this technology. The quadriga of acrylic acid, methyl acylate, acrylamide, and bis-acrylamide works in perfect synergy, as each component conveys a specific feature to the final product: a stable bond to the mucosa, the formation of networks, resistance to digestive juices, and hydrophobicity.

High adhesion strength

In lab experiments, the polymer system met the researchers’ expectations.

Anthis said: “Adhesion is up to ten times higher than with conventional adhesive materials.

“Further analysis also showed that our hydrogel can withstand five times the maximum pressure load in the intestine.”

A unique element to the material’s design is its tailored effect. The rubbery composite selectively reacts with digestive juices that might leak through intestinal wounds, expanding and closing tightly. The inexpensive, biocompatible super glue, which consists largely of water, could therefore help to shorten hospital stays and save healthcare costs.

Anthis, who is now already planning the next steps towards clinical application of the new wound plaster, added: “We are in the process of founding a start-up company to bring this innovative material to the market.”


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