Researchers Develop New Bacteria-Fighting Wound Dressing

Discovery could prevent tens of thousands of infections each year, investigator says

Scientists in Poland have developed a new type of wound dressing that uses an antibacterial substance extracted from the shells of crustaceans, such as shrimp. Their research is described in the May issue of Radiation Physics and Chemistry.

The protective dressing was developed by Dr. Radoslaw Wach and his colleagues at the Lodz University of Technology. Their research built on a type of dressing that has been around for centuries. By providing moisture to a wound, hydrogel dressings can speed up certain aspects of healing and cool the wound down. The dressings are durable and elastic, meaning they can easily adapt to the shape of the affected body part.

Wach and his colleagues adapted the manufacturing technique for hydrogel dressings by incorporating chitosan––an antibacterial and biodegradable substance from the shells of crustaceans––within the dressing itself.

The extraction process involves isolating chitin, a substance found in the crustacean shells, and then changing its structure by removing most chemical branches from its acetyl groups. The resulting chitosan then has to be purified before it is used. Chitosan is used in bandages to stop bleeding and has been known for its antimicrobial properties for decades.

Wach and his colleagues used irradiation to combine chitosan with hydrogel dressings. The method consists of cross-linking hydrophilic polymers next to water—as in basic hydrogel dressings—to form the structure of the dressing and sterilize it in a single step. The researchers next shone an electron beam at the polymer containing a solution of chitosan in lactic acid while making the dressings. This allowed the chitosan to become part of the dressing itself.

“We developed a composition where chitosan is dissolved in lactic acid, and when added to the regular composition of the dressing, it does not adversely change its ability to cross-link during manufacturing or alter its mechanical and functional properties,” Wach said. “The new hydrogel wound dressing is biologically active.”

Wach hopes the new dressing will one day be used as a replacement for classic hydrogels. “Since wound healing in severe cases may take a long time—up to several weeks—the probability of bacteria-mediated infection is high,” he said “Our novel hydrogel dressing could prevent many such infections and avoid serious complications.”

Last month, the World Health Organization (WHO) published a list of bacteria for which new antibiotics are needed. The most critical group of pathogens included multidrug-resistant (MDR) bacteria, which pose a particular threat in hospitals and nursing homes, and among patients whose care requires devices, such as ventilators and blood catheters. These MDR organisms include Acinetobacter, Pseudomonas, and various Enterobacteriaceae, including Klebsiella, Escherichia coli, Serratia, and Proteus. Moreover, 480,000 people develop MDR tuberculosis globally each year, according to the WHO, and drug resistance is complicating the fight against human immunodeficiency virus (HIV) and malaria.

“If our solution is commercialized,” Wach concludes, “tens of thousands of infections could be prevented each year.”

Source: Medical Xpress; May 1, 2017.