FDA OKs highly microbicidal wound dressing

By John Murphy, MDLinx
Published August 8, 2016

Key Takeaways

The U.S. Food & Drug Administration has given Imbed Biosciences clearance to market a novel nanofilm wound dressing called Microlyte Ag that destroys more than 99% of bacteria it touches.

The dissolvable wound dressing is as thin and as clingy as Saran Wrap—it adheres to the skin surface and is flexible enough to conform to a wound’s bumps and fissures, according to its developers.

To kill bacteria, Microlyte Ag contains silver nanoparticles—but in a much smaller proportion than in other dressings now used to treat burns and chronic wounds.

“Silver is an excellent antimicrobial agent as it is active against a broad range of bacteria and yeast,” explained Ankit Agarwal, PhD, CEO of Imbed Biosciences, in Fitchburg, WI. “But the large silver loads found in conventional silver dressings can be toxic to skin cells.”

He added, “Our dressing uses as little as 1% as much silver as the competition, and yet the tests we submitted to the FDA showed that Microlyte kills more than 99.99% of bacteria that it contacts.”

The nanofilm even proved microbicidal to hospital-acquired infections such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus, according to research.

“Chronic bacterial contamination of the wound surface, even when it looks relatively healthy, is a significant factor inhibiting healing in many cases,” said Jonathan F. McAnulty, DVM, PhD, a co-founder of Imbed Biosciences and Professor and Chair of Surgical Sciences in the School of Veterinary Medicine at University of Wisconsin-Madison.

“Once we treat with our dressing, we start to see very dramatic closure of these wounds,” Dr. McAnulty noted.

The ultra-thin dressing was invented at the College of Engineering at University of Wisconsin-Madison. It’s intended for diabetic ulcers, venous ulcers, burns, bedsores, and other chronic and difficult-to-heal wounds.

The dressing is comprised of two layers—a polymeric nanofilm embedded with silver nanoparticles that is laminated to a soluble film of polyvinylalcohol (PVA) only 1 micrometer thick. When the dressing is placed on a moist wound, the PVA dissolves and leaves the silver-loaded nanofilm immobilized on the wound bed.

The slow release of the silver means the dressing can remain in place for at least an entire day. Also, because the material is a hydrogel, it can simply be cleaned off as needed before replacement. These features can reduce the frequency of dressing changes, the developers explained.

“Reducing or eliminating dressing changes reduces the pain that the patient experiences,” said surgeon Michael Schurr, MD, a co-founder of Imbed Biosciences and Chair of General Surgery at the Mountain Area Health Education Center in Asheville, NC.

“It also reduces costs in supplies and reduces the burden to the health care system that supplies visiting nurses to do the dressing changes,” Dr. Schurr added.

The company is now deciding how to scale up production to commercial level, while seeking to market Microlyte Ag through hospital suppliers.

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