Dordick said the nanotube-enzyme coating builds on several years of previous work embedding enzymes into polymers. In previous studies, Dordick and Kane discovered that enzymes attached to carbon nanotubes were more stable and more densely packed when embedded into polymers than enzymes alone.
"If we put an enzyme directly in a coating (such as paint) it will slowly pop out," Kane said. "We wanted to create a stabilizing environment, and the nanotubes allow us to do that."
Having established the basics of embedding enzymes into polymers, they turned their attention to practical applications.
"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.
"It's very effective. If you put a tiny amount of lysostaphin in a solution with Staphylococcus aureus, you'll see the bacteria die almost immediately," Kane said.
Lysostaphin works by first attaching itself to the bacterial cell wall and then slicing open the cell wall (the enzyme's name derives from the Greek "lysis" meaning "to loosen or release").
"Lysostaphin is exceptionally selective," Dordick said. "It doesn't work against other bacteria and it is not toxic to human cells."
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 more the lysostaphin is able to move around, the more it is able to function." Dordick said.
They successfully tested the resulting nanotube-enzyme conjugate at Albany Medical College, where Metzger maintains strains of MRSA.
"At the en
|Contact: Mary Martialay|
Rensselaer Polytechnic Institute