Spinoff company with SVM ties gets FDA OK

Wisconsin State Farmer


Imbed’s Microlyte dressing is applied to a wound on a pig. The ultra-thin dressing conforms to the wound, bringing the antimicrobial silver into direct contact with bacteria.

Fitchburg — Imbed Biosciences, a medical device start-up company co-founded by scientists from the UW School of Veterinary Medicine (SVM), has received clearance from the Food and Drug Administration to market its patented wound dressing for human use.

The dressing it calls Microlyte Ag is a sheet as thin as Saran Wrap that can conform to the bumps and crevices of a wound, says company CEO Ankit Agarwal. As of August 2016, the dressing was cleared by the FDA as a class II medical device for prescription and over-the-counter use.

Like many dressings now used to treat burns and other persistent wounds, Microlyte Ag contains silver to kill bacteria – but in much smaller quantities.

“Silver is an excellent antimicrobial agent,” says Agarwal, a co-founder of the Fitchburg, Wis.-based company, “as it is active against a broad range of bacteria and yeast. But the large silver loads found in conventional silver dressings can be toxic to skin cells. Our dressing uses as little as 1 percent as much silver as the competition, and yet the tests we submitted to the FDA showed that Microlyte kills more than 99.99 percent of bacteria that it contacts.”

That kill ratio even appeared in tests against some of the nastiest hospital-acquired superbugs, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus.

Microlyte also overcomes a key problem with existing dressings: stiffness. Under a low-power microscope, a wound has bumps and fissures — hiding places for bacteria. The Microlyte dressing inherently adheres to moist surfaces and is so flexible that it drops into the fissures, leading to the sweet combination of greater destruction of bacteria at much lower doses of silver.

Although it retains moisture, Microlyte is also ultrathin and breathable, allowing oxygen to reach the wound and gases to exit, all factors that promote healing. The slow release of the silver means the dressing can remain in place for at least one day. And because the material is a hydrogel (i.e., water based), it can simply be rinsed off as needed before replacement.

Experience with animals shows that the ultra-thin dressing simply sloughs off as the wound heals. All of these advantages should reduce the need to change dressings, which can be so painful that sedation is needed, especially for children. In addition to reducing pain, limiting the number of bandage changes cuts down on supply costs and nurse visits.

“We are seeing in a limited number of cases that it does provide us with a remarkable new tool for dealing with chronic wounds” in dogs and cats treated at the SVM, says Jonathan McAnulty, chair of the Department of Surgical Sciences. “We certainly have no reason to think that this will be different with humans,” adds McAnulty, who is also a company co-founder. “The principles are the same, and a lot of the problems are the same.”

The dramatic closure of wounds that have resisted months of conventional treatment “suggests that chronic bacterial contamination of the wound surface, even when it looks relatively healthy, is a significant factor inhibiting healing in many cases,” McAnulty says. “Once we treat with our dressing, we start to see very dramatic closure of these wounds.”

McAnulty says he’s starting to use Microlyte earlier in treatment. “Certainly it seems appropriate for prevention of infection as well as treatment.”

The ultra-thin dressing material was invented in the lab of Nicholas Abbott, a UW–Madison professor of chemical and biological engineering, when Agarwal was a postdoctoral fellow. During the development of the new disinfectant technology, Charles Czuprynski, professor and chair of the SVM’s Department of Pathobiological Sciences and also a company co-founder, lent his extensive knowledge on the formation of biofilms.

The dressing will compete in the $2 billion market sector of “advanced wound dressings,” which are used to treat diabetic ulcers, venous ulcers, burns, bedsores and other difficult wounds.

Imbed has 10 employees. The company is developing other ideas for wound treatment and discussing commercial-scale production of Microlyte. Currently, it plans to reach the market through licensing agreements with hospital suppliers.