Permanent Antibacterial Coating Suited for Device Use
A polymer coating that adheres permanently to a variety of surfaces uses a powerful electrochemical action to kill some common bacteria that cause serious infections. Developed at Massachusetts Institute of Technology (Cambridge, MA; www.mit.edu), the hexyl-PVP compound has an intrinsic positive charge that destroys the cell walls and membranes of Staphylococcus, Pseudomonas, and E. coli. This kill mechanism makes it unlikely that bacteria could develop a tolerance, a problem for some antibiotic coatings. But the main benefit of hexyl-PVP is permanency. "Antibacterial agents that use a positive charge are not new," says Tony Dallmeyer, director of microbiology for Surmodics Inc. (Eden Prairie, MN; www.surmodics.com), an antibacterial coating company. "What makes this advance unique is that the scientists have been able to instill these qualities permanently in a solid surface coating." Hexyl-PVP attaches chemically so it can't be washed away. The compound is suited for incorporation into the manufacturing processes of many devices, including surgical instruments. According to the research team, the only required maintenance is periodic washing to remove dead bacteria.
Initial testing has demonstrated this coating to be very effective. Published in the May 22, 2001, Proceedings of the National Academy of Sciences, these results show that hexyl-PVP kills 9499% of Staphylococcus and a consistent 99% of Pseudomonas and E. coli. The material was tested by spraying coated slides with a concentrated solution of these bacteria to simulate the effects of coughing or sneezing. The material was also successfully tested for human toxicity using mouse cells. Though the MIT researchers hold a patent on the coating and are performing further testing, they are not currently involved in any effort to bring this technology to market.