The ability of copper to defend the health of people and animals against microorganisms such as bacteria and fungi is scientifically proven and certified.
According to this evidence, a series of initiatives began to emerge to promote the use of copper, in addition to undertakings that sought to transfer the antimicrobial properties of copper to different materials and formats, using copper fibers, copper additives based on salts, copper sulfate, and copper microparticles and nanoparticles, in order to generate textiles, polymers, melamines and other products in segments where metallic copper is unable to reach.
Antimicrobial Copper Nanoparticles
Copper nanoparticles display unique characteristics including catalytic and antimicrobial properties not seen in commercial copper. First, copper nanoparticles demonstrate very strong catalytic activity: a property that can be attributed to their large catalytic surface area. With the small size and high porosity, nanoparticles can achieve higher reaction yield and shorter reaction time when used as reagents in organic and organometallic synthesis.
Copper nanoparticles can serve as antibacterial agents. Antimicrobial activity is induced by its close interaction with microbial membranes and their metal ions released in solutions. As nanoparticles slowly oxidize in solutions, cupric ions are released from them and these can create toxic hydroxyl free radicals when the lipid membrane is closed. Then, free radicals disassemble lipids in cell membranes through oxidation to degenerate the membranes. As a result, intracellular substances leak out of cells through destroyed membranes and cells can no longer sustain fundamental biochemical processes. Ultimately, all of these alterations within the cell caused by free radicals lead to the cell death of the microorganism.
In February 2008, the U.S. Environmental Protection Agency (EPA) approved the registration of 275 antimicrobial copper alloys. By April 2011, that number expanded to 355. This permits public health claims that copper, brass and bronze are capable of killing harmful, potentially deadly bacteria. Copper is the first solid surface material to receive this type of EPA registration, which is supported by extensive antimicrobial efficacy testing.*
* U.S. EPA registration is based on independent laboratory tests showing that, when cleaned regularly, copper, brass and bronze kill greater than 99.9% of the following bacteria within 2 hours of exposure: Methicillin-resistant Staphylococcus aureus (MRSA), Vancomycin-resistant Enterococcus faecalis (VRE), Staphylococcus aureus, Enterobacter aerogenes, Pseudomonas aeruginosa, and E. coli O157:H7.
The Centers for Disease Control and Prevention (CDC) estimates that infections acquired in U.S. hospitals affect two million individuals every year and result in nearly 100,000 deaths annually. The use of copper alloys for frequently touched surfaces, as a supplement to existing CDC-prescribed hand-washing and disinfection regimens, has far-reaching implications.
Initial studies at the University of Southampton, UK, and tests subsequently performed at ATS-Labs in Eagan, Minnesota, for the EPA show that copper-base alloys containing 65% or more copper are effective against:
- Methicillin-resistant Staphylococcus aureus (MRSA)
- Staphylococcus aureus
- Vancomycin-resistant Enterococcus faecalis (VRE)
- Enterobacter aerogenes
- Escherichia coli O157:H7
- Pseudomonas aeruginosa.
These bacteria are considered to be representative of the most dangerous pathogens capable of causing severe and often fatal infections.
The EPA studies show that on copper alloy surfaces, greater than 99.9% of MRSA, as well as the other bacteria shown above, are killed within two hours at room temperature.