Sprayable Gel Applied During Endoscopic Procedures Helps Prevent Internal Bleeding, Makes Surgeries Safer and Easier

More than 15 million Americans undergo colonoscopy screenings every year. Doctors often remove polyps that measure 2 centimeters or larger and require additional medical care.

(Photo: Wikimedia Commons/ CSIRO)

Routine colon cancer screenings usually reveal small precancerous polyps, which can be removed before they become cancerous. The procedure typically uses an endoscope and may involve different methods, such as colonoscopy.

Safety in Colorectal Procedure

Colonoscopy has greatly reduced the overall incidence of colon cancer, but it also comes with complications. Patients may experience gastrointestinal bleeding both during and after the medical procedure.

If bleeding occurs during the polyp removal, doctors usually cauterize the wound to seal it. However, this technique can create a scar that could delay healing, resulting in additional complications.

In some patients, bleeding does not occur until a few days after the procedure. This can be dangerous and usually requires the patient to return to the hospital for additional treatment.

In other cases, the patients may develop small tears, which cause the intestinal contents to leak into the abdomen. This could result in a severe infection that requires emergency care. If the procedure requires tissue reinforcement, doctors usually insert metal clips to hold the tissue together, but this strategy cannot be used with larger polyps and is not always effective.

Sprayable Adhesive

Researchers at the Massachusetts Institute of Technology aim to prevent these complications from occurring. To that end, they have developed a new gel that can be sprayed through an endoscope onto the surgical sites.

Known as GastroShield, the gel forms a tough but flexible protective layer that serves as a shield for the damaged region. It prevents delayed bleeding during colonoscopy while reinforcing the mechanical integrity of the colorectal tissue. The details of their innovation are described in the paper "Sprayable Hydrogel Sealant for Gastrointestinal Wound Shielding."

GastroShield involves tissue-responsive adhesive technology engineered to interact with the tissue through complimentary covalent and ionic associations. It is also designed with physical interactions to offer prolonged lesion protection over days to avoid complications after polyp removal.

When tested in an animal study, the researchers found that the application of the new gel seamlessly integrates with conventional endoscopic procedures. It also provides wound protection for three to seven days while encouraging tissue healing after surgery. Members of the research team plan to develop GastroShield for human use further.

There have been efforts to develop a gel that can seal surgical wounds, but most were unsuccessful. The materials could not adhere to the surgical site for more than 24 hours.

In developing GastroShield, the researchers developed an innovative combination with a pluronic polymer. This is a type of block copolymer that can assemble itself into spheres known as micelles. The end of these polymers possess multiple amine groups that end up on the surface of the micelles. The gel also contains oxidized dextran, a polysaccharide that forms strong but reversible bonds with the amine groups of the pluronic micelles.

When these materials are sprayed, they react instantly with the gastrointestinal tract's lining, creating a solid gel in less than five seconds. The micelles that make up the GastroShield are self-healing, which means that they can absorb the forces they encounter from peristaltic movements and food moving along the gastrointestinal tract. As a result, they temporarily break apart and then reassemble themselves.