Sugary band-aid may help heal post-operative tissue

Results published June 1 in the Proceedings of the National Academy of Sciences show that a sticky gel composed of polyethylene glycol and a polycarbonate of dihydroxyacetone (MPEG-pDHA) may help to seal wounds created by surgery.

Procedures to remove cancerous breast tissue, for example, often leave a hollow space that fills with seroma fluid that must typically be drained by a temporary implanted drain. "This is an unpleasant side effect of surgery that is often unavoidable," explains Dr. Jason Spector, co-author of the study and plastic surgeon at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

The gel could potentially be used in all different reconstructive surgeries to prevent seroma formation. "The new substance would act to glue together the hole left behind to prevent seroma buildup," says Dr. Spector.

DHA is a compound that sticks to compounds in biological tissues, called amines. The sticky properties of DHA are what allows sunless tanner to adhere to the skin without being wiped off. However, it is biodegradable and water soluble as well, which means that the compound does not stay tacked onto the body's tissues forever. Currently used "bio-glues" are made from animal products and take a long time to degrade in the body -- both factors that raise the risk of infection.

"DHA is a compound that is naturally produced in the body," explains Dr. David Putnam, the study's senior author and a biomedical engineer from Cornell University's Department of Biomedical Engineering and School of Chemical and Biomolecular Engineering. "The glue is broken down, or metabolized, and then safely removed by the body."

Dr. Putnam's lab and his collaborators work to create safe, synthetic compounds from chemicals found in nature. DHA is an intermediary compound produced during the metabolism of glucose, a sugar used by the body for fuel.

To create the new compound, MPEG-pDHA, Dr. Putnam and his lab first bound the single molecule monomer of DHA, which is highly reactive, to a protecting group molecule, making it stable enough to manipulate. This allowed the engineers to bind the monomers together to form a polymer, or chain of molecules, along with MPEG. Doing so allows the polymer gel to be injected through a syringe.

"Making a polymer from DHA has eluded chemical engineers for about 20 years," says Dr. Putnam.

Now in gel form, the compound has the ability to stick tissues together, preventing the pocket from filling with seroma fluid, like an internal Band-Aid, explains Dr. Putnam. The researchers found that the gel prevented or significantly lowered seroma formation or fluid buildup in rats that had breast tissue removed.

"The next step would be to test the gel on larger animals and then in clinical trials in human surgical cases," says Dr. Spector.

Previous results, published by Drs. Putnam and Spector, in the August 2009 issue of the Journal of Biomedical Materials Research, showed that the gel also prevented bleeding in a rat liver.

"This is another aspect of the compound that would be greatly beneficial if proven to be applicable in humans," says Dr. Spector. "The gel could speed the healing and decrease bleeding within the body."

This research was supported in part from a National Science Foundation CAREER Award, a grant from the Morgan Tissue Engineering Fund, an Early Career Award from the Wallace H. Coulter Foundation, and the New York State Center for Advanced Technology.

Co-authors of the study include Dr. Peter Zawaneh from Cornell University, Dr. Sunil Singh and Dr. Peter Henderson from Weill Cornell, and Dr. Robert Padera from the Department of Pathology at Brigham and Women's Hospital.