Copper, a reddish-brown metal, has long been recognized for its ability to combat harmful microorganisms. This ancient knowledge, dating back thousands of years, is now supported by modern science. Copper and its alloys possess inherent properties that inactivate a wide range of bacteria, viruses, and fungi. This natural antimicrobial characteristic makes copper a valuable material where hygiene is a priority.
How Copper Kills Microbes
The antimicrobial action of copper primarily stems from a phenomenon known as the “oligodynamic effect,” where even small concentrations of copper ions can be toxic to living cells. When microbes come into contact with a copper surface, copper ions (Cu⁺ and Cu²⁺) are released and begin to interact with the microbial cells. These ions create an electrical short-circuiting of the cell membrane, weakening its structure and forming holes.
Once the cell membrane is compromised, essential nutrients and ions leak out, while an increasing number of copper ions enter the cell. Inside the microbe, copper ions generate reactive oxygen species (ROS), such as hydrogen peroxide, which cause oxidative stress. This oxidative damage targets and harms vital cellular components like proteins, lipids, and nucleic acids.
Copper ions also directly interfere with proteins and enzymes essential for a microbe’s metabolism and respiration. By binding to these proteins, copper can alter their three-dimensional structure, rendering them non-functional. Furthermore, copper interacts with the genetic material, DNA and RNA, causing damage such as mutations and strand breaks, which prevents the microbe from replicating. These combined actions lead to rapid and irreversible cell death, even for strains that have developed resistance to antibiotics.
Where Copper is Used to Fight Germs
The antimicrobial properties of copper have led to its application in diverse environments to reduce the spread of pathogens. In healthcare settings, copper alloys are used on high-touch surfaces such as door handles, bed rails, IV poles, and medical equipment. Studies show copper surfaces can reduce bacterial contamination by over 99.9% within two hours, significantly lowering the risk of hospital-acquired infections.
Beyond hospitals, copper is integrated into public spaces. This includes handrails in public transit systems, shopping cart handles, and surfaces in airports and commercial buildings. The continuous germ-killing action of copper on these surfaces helps mitigate the transmission of infectious diseases.
Copper’s antimicrobial benefits also extend to consumer products and water purification systems. Copper-infused textiles, such as socks and face masks, inhibit microbial growth. Additionally, copper compounds are utilized in water treatment to prevent biofouling and maintain water quality.