Making A Hydrogel Label For Wound Healing
Researchers Have Developed A Hydrogel Label That Can Be Used After Abdominal Surgery To Close Wounds And Detect Discharge From The Suture Site.
Suture discharge after abdominal surgery is a potentially life-threatening complication that surgeons may not immediately recognize.
When a surgeon, for example, removes a section of the intestine and stitches the two ends together, called an anastomosis, there is a chance that the suture site will ooze. The problem is that when the skin is closed, the surgeon may not be aware of the presence or absence of secretions within the abdominal cavity.
Anastomotic leakage causes very acidic stomach fluids to spill into the abdominal cavity. It can lead to severe complications such as inflammation and infection of the tissues covering the cavity (peritonitis) and life-threatening blood infection (sepsis). The discharge is often discovered only when the patient has symptoms such as pain and fever that affect his general health.
The problem with making a device that helps close the anastomosis or controls its secretion is that it has to withstand the high acidity of the digestive fluids without breaking down. Researchers from the Swiss Federal Laboratories for Materials Science and Technology (Empa) and ETH Zurich have developed a secretory adhesive that can withstand the gut’s acidic environment and help wound closure.
Researchers have developed a hydrogel sticker that can be used after abdominal surgery to hold wounds and detect discharge from the suture site.
“Surgeons have told us that even in the most complex procedures, they are closely monitoring the surgical site, but as soon as the abdominal cavity is closed, they are blinded and may notice discharge when it is too late,” said Alexander Antis, one of the authors of the study.
This adhesive consists of a layered hydrogel matrix in which carbonate, barium, or lanthanum salts are embedded and act as non-electronic sensors. Barium carbonate is now commonly used as an X-ray contrast agent, while lanthanum carbonate is used to reduce high blood phosphate levels caused by kidney disease.
When carbonate comes into contact with acidic digestive fluids, it breaks down and produces bubbles of carbon dioxide that are trapped in the hydrogel matrix. Bubbles can be seen using ultrasound because they stand out from the surrounding tissue due to their high contrast.
As a kind of support secretion detection mechanism, this tag also changes shape in the presence of digestive fluids as a ring or line, which can be detected by computed tomography scanning.
This means the title provides a dual-mode assay, and the secretion is visible in ultrasound and tomography.
In the future, a sensor whose shape is distinguishable from anatomical structures in tomography and ultrasound images could reduce the ambiguity of detecting impending discharge, said study co-author Inge Herrmann.
Testing their label in pig models, the researchers found that both carbonates only reacted to the acidic conditions associated with contact with gastric fluids and were, therefore, less likely to give false positives. Depending on the area of secretion, the reaction caused by contact with stomach acid occurs within a few minutes or hours. Typically, healthcare professionals must rely on clinical signs of discharge, which may take time to materialize.
a) Surgery exposes the patient’s stomach to the risk of postoperative complications due to the re-secretion of connective tissue and the release of gastric fluids into the abdominal cavity. b) The dual-mode secretion detector label enables early detection of secretion by computed tomography (CT) and ultrasound (US) based on contrast changes due to barium (or lanthanum) carbonate breakdown and carbon dioxide (CO2) bubble formation.
In addition, the carbonate sensors are also encapsulated in polyacrylamide, a water-absorbing polymer that allows the adhesive to adhere firmly to the wound site, sealing it while preventing movement. According to the researchers, this could reduce the risk of complications after abdominal surgery and shorten the hospital stay.
The researchers say their device offers a cost-effective way to detect discharge and allow for timely treatment quickly. Of course, more studies are needed to determine the long-term fate of the wound-retaining sensor adhesive.
