BEVERLY HILLS – Silver has been used for medicinal purposes for centuries and, in modern times, several prescription drugs contain the precious metal. For example, silver nitrate is used to prevent the eye condition conjunctivitis (inflammation of the conjunctiva, the clear membrane that covers the white part of the eye and the inner surface of the eyelids) in newborn babies and it treats corns and warts, too. Another medication, silver sulfadiazine (sold as Silvadene) contains a micronized form of silver that is applied topically to the body to treat burns. And now researchers have found that when silver is used with copper, the combination may offer protection against the majority of serious hospital-acquired infections.
The germ-killing properties of copper, like those of silver, have been recognized for hundreds of years. Scientists have discovered that copper ions are deadly to bacteria because they penetrate the micro-organisms and disrupt molecular pathways that are important for their survival. In fact, in 2008 the U.S. Environmental Protection Agency (EPA) officially registered copper alloys and allowed them to be marketed with the label “kills 99.9% of bacteria within two hours”.
Scientist Dana Filoti successfully tested her hypothesis that the combination of silver and copper would work better to kill bacteria than the metals alone. She created zeolite (a porous mineral) ceramic structures to hold the metals. “The hard ceramic structure looks like Swiss cheese and inside the holes there are ions of silver and copper,” Filoti explained in a statement to the press. By experimenting with the ratio of copper to silver and the texture of extremely thin films containing the metals, she was able to almost totally wipe out all microbes on the surface.
Filoti, a University of New Hampshire physicist, presented her findings at the recent national meeting of the American Vacuum Society (AVS), an organization that promotes the science and technology of materials, interfaces and processing, held in San Jose, California. Filoti unveiled her copper/silver films and told the group of scientists and engineers that silver and copper do work synergistically to effectively kill bacteria, including the type of pathogens that too often cause difficult-to-treat infections acquired in hospitals.
A practical application of the silver and copper combo’s amazing ability to kill germs is on the horizon. Filoti is working with a New Hampshire company to design an antimicrobial face mask that will protect wearers against pathogens known to cause many hospital-acquired infections.