New anti-microbial 'paint' kills flu, bacteria

"In the U.S., more people die in hospitals of diseases they didn't have when they got to the hospital than from the disease that prompted them to go to the hospital in the first place," said Klibanov, who anticipates the new material would be useful in a hospital setting, as well as others where people congregate.

The new coating acts in a very different way from the many antibacterial products--such as soaps, sponges, cutting boards, pillows, mattresses and even toys--that are now on the market.

Those products--which kill bacteria but not viruses--depend on a timed release of antibiotics, heavy metal ions or other biocides, a system that has many drawbacks, says Klibanov. Once all of the biocide has been released, the antimicrobial activity disappears. Also, it can be harmful to release all of these biocides into the environment.

One of the benefits of the new polymer coating is that it is highly unlikely that bacteria will develop resistance to it, Klibanov said. Bacteria can become resistant to traditional antibiotics by adjusting the biochemical pathways targeted by antibiotics, but it would be difficult for bacteria to evolve a way to stop the polymer spikes from tearing holes in their membranes.

"It's hard to develop resistance to someone sticking a knife in your body," Klibanov said.

In a prior experiment designed to test for resistance, 99 percent of bacteria that were exposed to a polymer-coated surface died. The researchers then took the surviving one percent, let them multiply and again exposed them to the surface. They repeated the cycle 12 times, and each time, approximately 99 percent of the bacteria were killed, suggesting that the microbes were not becoming resistant.

The MIT researchers are working with industrial and military partners such as Boeing and the Natick Army Research Center to develop the coatings for practical use.

Once the polymer coating is applied to a surface, it should last about as long as a regular coat of paint, Klibanov said. Accumulation of dead bacteria and viruses diminishes the effectiveness of the nanometer-sized polymer spikes, so the surface would need to be washed with soapy water every once in a while to remove dead microbes, he said.

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