Inside Rensselaer
* Researchers Develop Coating That Safely Kills MRSA on Contact
Image credit: Rensselaer/Ravindra C. Pangule
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Researchers Develop Coating That Safely Kills MRSA on Contact

Building on an enzyme found in nature, researchers at Rensselaer have created a nanoscale coating for surgical equipment, hospital walls, and other surfaces that safely eradicates methicillin resistant Staphylococcus aureus (MRSA), the bacteria responsible for antibiotic resistant infections.

“We’re building on nature,” said Jonathan Dordick, the Howard P. Isermann Professor of Chemical and Biological Engineering and director of the Center for Biotechnology and Interdisciplinary Studies. “Here we have a system where the surface contains an enzyme that is safe to handle, doesn’t appear to lead to resistance, doesn’t leach into the environment, and doesn’t clog up with cell debris. The MRSA bacteria come in contact with the surface, and they’re killed.”

In tests, 100 percent of MRSA in solution were killed within 20 minutes of contact with a surface painted with latex paint laced with the coating.

The new coating marries carbon nanotubes with lysostaphin, a naturally occurring enzyme used by non-pathogenic strains of Staph bacteria to defend against Staphylococcus aureus, including MRSA. The resulting nanotube-enzyme “conjugate” can be mixed with any number of surface finishes — in tests, it was mixed with ordinary latex house paint.

“We asked ourselves, were there examples in nature where enzymes can be exploited
that have activity against bacteria?” Dordick said. The answer was yes.

Unlike other antimicrobial coatings, it is toxic only to MRSA, does not rely on antibiotics, and does not leach chemicals into the environment or become clogged over time. It can be washed repeatedly without losing effectiveness and has a dry storage shelf life of up to six months.

The research, led by Dordick and Ravi Kane, the P.K. Lashmet Professor of Chemical and Biological Engineering, along with collaboration from Dennis Metzger at Albany Medical College and Ravi Pangule, a chemical engineering graduate student on the project, has been published in the July edition of the journal ACS Nano, published by the American Chemical Society.

“We asked ourselves — were there examples in nature where enzymes can be exploited that have activity against bacteria?” Dordick said. The answer was yes and the team quickly focused on lysostaphin, an enzyme secreted by non-pathogenic Staph strains, harmless to humans and other organisms, capable of killing Staphylococcus aureus, including MRSA, and commercially available.

The enzyme is attached to the carbon nanotube with a short flexible polymer link, which improves its ability to reach the MRSA bacteria, said Kane. The team successfully tested the resulting nanotube-enzyme conjugate at Albany Medical College, where Metzger maintains strains of MRSA.

“At the end of the day we have a very selective agent that can be used in a wide range of environments — paints, coating, medical instruments, doorknobs, surgical masks—and it’s active and it’s stable,” Kane said. “It’s ready to use when you’re ready to use it.”

Kane also said MRSA are unlikely to develop resistance to a naturally occurring enzyme.

“Lysostaphin has evolved over hundreds of millions of years to be very difficult for Staphylococcus aureus to resist,” Kane said. “It’s an interesting mechanism that these enzymes use that we take advantage of.”

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Inside Rensselaer
Volume 4, Number 12, August 27, 2010
©2010 Rensselaer Polytechnic Institute
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