Antimicrobial copper: the metal that fights germs
Copper has a wide range of uses in electronics, infrastructure, and energy technology. Red metal is practically everywhere, from the wires of our devices to the buildings we live in.
However, the medicinal applications of copper, which date back thousands of years, are not as widespread in the modern world.
In this infographic from our sponsor Metals Trilogy, we are exploring copper’s ability to fight bacteria and its growing role in modern healthcare.
Dr. Copper: How copper fights germs
Copper is naturally antimicrobial, and ancient civilizations recognized this property. The Egyptian Papyrus Smith recorded the first medical use of copper thousands of years ago. Since then, several generations have passed on their knowledge of the medicinal uses of copper.
But how does copper kill germs?
According to Copper Development Association, copper surfaces affect bacteria in a series of sequential steps:
# 1: break the cell
The outer cell membrane of each bacterium is characterized by an electric microcurrent, called “transmembrane potential”. It is suspected that when a bacteria is exposed to a copper surface, it causes a short circuit of the current in the cell membrane, which weakens the membrane and creates holes.
Localized oxidation is another mechanism by which copper breaks down bacterial cells. This occurs when a copper ion comes in contact with a protein or fatty acid in the cell membrane of the bacteria in the presence of oxygen, which causes oxidative damage to the cell membrane.
# 2: disrupt cell function
Once copper crosses the cell membrane, essential nutrients begin to escape from the cell. At the same time, an increasing number of copper ions enter the cell and obstruct essential metabolic activity. This reaction is catalyzed by enzymes, and as the excess copper binds to the enzymes, their activity stops.
# 3: remove the germ
With an overwhelming amount of copper ions obstructing the bacteria’s metabolism, it cannot “breathe”, “eat” or “create energy” which effectively eliminates the bacteria.
More 500 Antimicrobial copper alloys are registered with the US Environmental Protection Agency (EPA). This means that the antimicrobial copper alloys have passed the EPA performance standard for antimicrobial efficacy of solid touch surfaces, and it is safe to say that the antimicrobial copper kills 99.9% of certain bacteria within two hours. But that doesn’t tell the whole story.
The real value of antimicrobial copper lies in its ability to kill bacteria continuously after repeated contamination events. This means that the antimicrobial copper provides continuous protection against bacteria without wearing out.
However, the EPA notes that using a copper surface does not replace standard infection control practices and that copper alloys do not necessarily prevent cross contamination. Therefore, users should continue to follow current infection control practices, including cleaning and disinfecting environmental surfaces.
Copper vs COVID-19
High contact surfaces play a major role in the spread of COVID-19, and copper can help stop the spread.
According to a study by New England Journal of Medicine, the SARS-CoV-2 virus can live up to three days on plastics, against four hours on copper surfaces. Additionally, based on testing against more difficult-to-kill viruses, the EPA expects antimicrobial copper surfaces to remove 99.9% of SARS-CoV-2 within two hours.
Copper’s ability to fight bacteria and germs enables antimicrobial applications in several industries.
The applications of antimicrobial copper
From healthcare to transportation, virtually any industry can improve hygiene by installing antimicrobial copper on frequently touched surfaces.
For example, a trial by TransLink, Teck Resources Ltd. and Vancouver Coastal Health have found that copper kills up to 99.9% of bacteria on high-traffic surfaces in transit vehicles. This suggests that simply installing antimicrobial copper on handrails, doorknobs, and poles can provide people with additional protection from germs.
Additionally, copper can be a very effective antimicrobial surface in healthcare settings where the risk of infection is higher. A to study by Schmidt et al., published in the Applied and Environmental Microbiology Journal, found that hospital beds with copper surfaces housed 95% less bacteria than conventional beds.
Additionally, sports facilities, airports and restaurants have also used antimicrobial copper as a protective layer. As more industries recognize copper’s antimicrobial properties, its applications will likely continue to grow.
New meaning for Dr Copper?
Thousands of years after the ancient Egyptians, Greeks and Romans, the medicinal properties of copper are resurfacing.
With growing awareness of hygiene practices especially in healthcare facilities, the antimicrobial coatings market is expansion. Given copper’s effectiveness in killing harmful bacteria, the term “Doctor Copper” may find new meaning as its antimicrobial uses expand.