Penn State research leads to development of 'healing bandages'

University Park, Pa. -- It seems like a strange concept -- bandages made from cellulose produced by microbes that contribute to wound healing -- but to hear Jeffrey Catchmark explain it, the idea makes perfect sense.

After all, as the associate professor of agricultural and biological engineering in Penn State's College of Agricultural Sciences pointed out, traditional bandages are made from cellulose, too -- cotton gauze. But as anyone who has ever tried to pull one of those off a healing wound will painfully attest, they stick to knitting flesh, and when they finally separate, the wound often is torn open.

This disruption of the healing process -- and its associated invitation to infection -- is especially acute in cases of chronic wounds. But Catchmark, who is co-director of the University's Center for Lignocellulose Structure and Formation, has developed a bandage material made from microbial cellulose that actually is absorbed by the body. He has devised a way to incorporate enzymes with the bandage that break down the cellulose in a controlled way.

It wasn't until Catchmark had a conversation with representatives of a health care company in 2007 that the idea for the innovative bandage material crystallized in the researcher's mind. Bayer Innovation officials had attended an industry crossover event at Penn State and were intrigued by a presentation Catchmark gave, in which he suggested a promising new approach for "bioresorbable" materials.

The conversation soon led to a partnership between Bayer and the College of Agricultural Sciences. Bayer Innovation was interested in bio-absorbable wound-care materials, particularly for chronic wounds, recalled Catchmark. The goal was to develop a material that would aid in the healing of wounds and would degrade over time.

"This is important for most wounds, but specifically chronic wounds because you don't want the healing tissue to integrate with a nondegradable material such as gauze," he said. "After the wound is healed and you remove the bandage, some of that gauze might be embedded in the tissue. If you pull at the gauze, it disturbs the healing tissue. Ideally, you'd like to have a material that facilitates the healing process but also vanishes."

Catchmark's solution was to combine a nanofiber-type of cellulose with cellulose-degrading enzymes, and his research results became the basis of a patent application.

"One of the reasons that this approach works is because the bio-absorbable material degrades into glucose," he explained. "The glucose just becomes a part of the sugars in the blood stream." 

Working together, Catchmark and Bayer Innovation solved technical issues of selecting the enzymes and suspension compounds that are compatible with wound healing. The group also discovered a way to enhance the product's manufacturability.

"The crux of the problem, and perhaps the reason why no one has done this in the past, is if you try to incorporate enzymes into the material when wet, they become active and the material starts to degrade," said Catchmark. 

To keep the material from degrading into a sugar solution before it can be used, Catchmark found that he could freeze-dry the microbial cellulose and temporarily arrest the conversion. "Now, you can simply open the bandage packet, hydrate the material using sterile water, and put it on the patient," he said. "The bandage is now in the testing phase -- we're hopeful that a product will be ready to manufacture soon."

The cellulose used in the novel bandages is produced by microbes called Acetobacter xylinum, according to Catchmark.

"It has been shown by past research that Acetobacter xylinum produces a lot of cellulose -- I don't know of another organism that can produce more. Cellulose is the chief substance composing the cell walls or fibers of all plant tissue. It dawned on me that since cotton gauze has been used in bandages for more than a century, microbial cellulose, in this case made by Acetobacter xylinum, should work just as well," he said.

In a promising development, Catchmark's research on the innovative bandage material is the basis of another patent application. Bayer Innovation believes the bio-absorbable cellulose can be further engineered to serve as a tissue scaffold for bone and cartilage regeneration.

"Ideally the scaffolding material degrades away into a harmless product," Catchmark said. "So much has been done in the area of wound care, and there is so much to be learned -- we have just scratched the surface with these tissue-scaffold materials and using enzymes to trigger their degradation."

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Last Updated November 18, 2010