Hospital Fixtures that Kill Infectious Bacteria
PMX Industries using expertise of Ames Laboratory’s
Materials Preparation Center to expand the range of new copper alloys
The wide-spread use of antibiotics has saved countless lives, but unfortunately, some of the bacteria responsible for common infections have grown resistant to these drugs. PMX Industries, Inc., located in Cedar Rapids, Iowa, has developed EPA-approved antimicrobial copper alloys for use in hospitals and public buildings – from handrails and door handles to metal surfaces – that, when cleaned regularly, kills greater than 99.9 % of certain drug resistant bacteria (MRSA)* within two hours, and continues to kill 99% of these bacteria* even after repeated contamination. Now, with help from the U.S. Department of Energy’s Ames Laboratory, PMX is developing additional alloys that will support a wider range of applications.
According to Rich Pratt, director of marketing and research and development at PMX, the company developed its MicroGuard™ antimicrobial copper alloys in late 2008. In testing prescribed by the U.S. Environmental Protection Agency, MicroGuard surfaces were found to kill 99.9 percent of methicillin-resistant Staphylococcus aureus, commonly referred to as MRSA, and four other bacteria* within two hours of contact. These bacteria can be found on touch surfaces within hospital and other settings.
“The exact mechanism by which copper kills has not been precisely defined, however, there are several theories being investigated currently,” said Pratt. “There are other metals which exhibit this behavior, but are not used due to toxicity, lack of durability when deployed, or are cost prohibitive.”
One key feature of the PMX copper alloys is that because they are solid metal, not a coating, the antimicrobial properties won’t wear away or be rubbed off. With normal cleaning and disinfection practices, the MicroGuard surfaces continue to kill infectious bacteria* for the life of the equipment.
While PMX has developed the alloys to match stainless steel in appearance and strength and offers hardware that includes handrails, grab bars, door handles, push plates, kick plates and light switch covers, the company’s research and development efforts continue. And that’s where Ames Laboratory, specifically the Lab’s Materials Preparation Center, comes into the picture.
“Chemistry control in small sample sizes, less than 200 grams, is challenging,” Pratt said. “It becomes even more complicated casting small lots (2-10kg) in industrial casting, since exposure to air causes oxidation and some elements slag out. This is particularly critical when some of the elemental additions are at concentrations of less than one percent.”
Pratt turned to the Materials Preparation Center (MPC) which starts with ultra-high purity materials and has expertise in developing alloys with precise chemical composition. According to Pratt, the MPC could produce new alloy combinations with a control not available elsewhere. PMX is testing those samples prepared by the MPC.
“We’ve worked with Rich on a number of samples,” said MPC Director Larry Jones. “In some cases PMX supplied the materials and he worked directly with our technicians to oversee the processing and to better understand what was taking place.”
“We also did some hot fabrication of the alloys we prepared,” Jones said, “producing both sheet material and rods. We routinely work with companies like PMX to provide the types of services and expertise they may not have in-house.”
Pratt is no stranger to the MPC and its capabilities. As an Iowa State University undergraduate in the mid 1980’s, he worked at the Center as a research assistant.
“I was studying metallurgical engineering and worked with a number of Ames Laboratory researchers in single crystal growth and characterization,” he said, “and later worked with Larry Jones on alloy preparation and Bridgeman crystal growth.”
“It’s always great to see former students do well,” Jones said. “It’s especially rewarding when they remember the training they received here and return to seek our help in solving a particular issue their company may be having with a material.”
*Independent laboratory testing demonstrated effective antibacterial activity against Methicillin-Resistant Staphylococcus aureus (MRSA), Escherichia coli 0157:H7, Staphylococcus aureus, Enterobacter aerogenes, and Pseudomonas aeruginosa.
~ by Kerry Gibson
The Materials Preparation Center is a DOE Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences & Engineering specialized research center located at the Ames Laboratory. MPC is recognized throughout the worldwide research community for its unique capabilities in the preparation, purification, single crystal growth, and characterization of rare earth metals, alkaline-earth metals, and refractory metal materials.
The Ames Laboratory is a U.S. Department of Energy Office of Science laboratory operated for the DOE by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global challenges.