A wound dressing that kills bacteria
In order to combat bacterial infections directly in the wound, Empa researchers have developed membranes made of cellulose that are equipped with antimicrobial protein building blocks. Initial results show: The skin-friendly membranes made from plant material kill bacteria extremely efficiently.
Urgent Germs into a wound, they can trigger a permanent infection that may not heal or may even spread throughout the body and lead to life-threatening blood poisoning (sepsis). Today, especially in complex wounds, the problem of the Antibiotic resistancebecause bacteria such as staphylococci have become insensitive to the former wonder weapon of medicine. Researchers at Empa have therefore developed cellulose membranes that can nip such infections in the bud.
The team led by Empa researcher Katharina Maniura from the "Biointerfaces" laboratory in St. Gallen used electrospinning to produce fine membranes from plant cellulose for this purpose. The cellulose fibers with a diameter of less than one micrometer were spun into a delicate three-dimensional fabric in several layers. The membranes became particularly flexible and at the same time stable after the researchers had additionally spun in the polymer polyurethane.
To make a antibacterial effect the researchers designed multifunctional protein building blocks - known as peptides - that can bind to the cellulose fibers and also exhibit antimicrobial activity. These peptides have the advantage that they are easier to produce and remain more stable than larger proteins, which are more sensitive to the chemical conditions in a wound.
Skin friendly membranes
When the cellulose membranes were treated with such a peptide solution, the fiber scaffold became saturated with the protein building blocks. In cell culture experiments, the researchers then demonstrated that the peptide-containing membranes are well tolerated by human skin cells. For bacteria such as staphylococci, which are often found in poorly healing wounds, however, the cellulose membranes were a death sentence. "In bacterial cultures, more than 99.99 percent of the germs were killed by the peptide-containing membranes," Maniura said.
In the future, the antimicrobial membranes will also be equipped with additional functions. "For example, the peptides could be functionalized with binding sites that enable the controlled delivery of additional therapeutic agents," Maniura said.
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