Research says copper disintegrates novel coronavirus – SARS-CoV-2- the moment it lands on the metal.
The global coronavirus pandemic has made everyone around cautious of hygiene and cleanliness. The transmission of microbes through droplets, touching, sneezing has brought a wave face masks, 20-seconds hand wash, alcohol-based hand wash, and sanitizers. However, ensuring only animate parts are sanitized is not enough. Healthcare-associated infection (HAI) pathogens can survive on inanimate surfaces for a longer duration, in some cases up to several months as shown by several pieces of researches.
The other important conduits for virus transmission are touch surfaces. Touch surfaces such as furniture, poles, doorknobs, touch plates, bed rails, call buttons, toilet seats, and other surfaces are highly contaminated with microbes. It was revealed by research conducted by Kramer A. et. Al., that pathogens such as Staphylococcus aureus and Acinetobacter spp. manage to persevere on such surfaces for months.
However, the viruses and other micro-organisms have a longer life-span on some surfaces compared with others. Similarly, novel coronavirus – SARS-CoV-2 lives longer on some than others. According to a paper published in The New England Journal of Medicine (NEJM), which evaluated the stability of SARS-CoV-2 in aerosols and other surfaces, estimated that SARS-CoV-2 was able to persist more on plastic and stainless steel than on copper and cardboard. A different shred of researches pointed out that the SARS-CoV-2 was able to survive on glass and stainless steel, and died within hours after landing on copper.
Copper – a biocidal has always been in the picture
The anti-bacterial properties of copper have long been under investigation. In the year 1852, Victor Burq observed lesser deaths of those engaged with copper somehow during the cholera outbreak.
Later in the time period, In the year 1973, researchers at Battelle Columbus Laboratories conducted comprehensive literature, technology and patent search demonstrating sanitizing properties of copper, in minimal quantities against a wide range of molds, fungi, algae and harmful microbes.
According to Professor Bill Keevil, University of Southampton, copper surfaces has led to a 90% reduction of microbial numbers. His research on studying the effect of copper on the virus is not a recent one. Back in time, during the outbreak of Legionella bacteria, he observed that the bacteria were unable to infect the people who used copper pipes for the dissemination of water. Moreover, the results were more or less similar in cases of E.coli.
The studies revealed that the moment microbial particles come in contact with the copper surface, they start to die, referred to as ‘contact killing‘. If the surface is wet it will take between 45 minutes and two hours to kill 10 million germs; however, the time taken in case of a dry surface, approximates to 10 minutes or even less.
As a result of several research papers that proved to be exigent, on February 29, 2008, the United States Environmental Protection Agency (EPA) approved the registrations of five different groups of copper alloys as “antimicrobial materials” with public health benefits. At present, The EPA copper registry covers 479 different compositions of copper alloys within six groups; and all of the alloys have minimum nominal copper concentrations of 60%.
What is so special about copper?
Presence of copper as an essential trace element in almost all the living organisms is not a recent discovery. The living body has more than 30 types of copper-containing proteins, which are known to date, including tyrosinase, dopamine β-hydroxylase, and others. These enzymes host copper either as an electron donor or as an electron acceptor by alternating between the redox states Cu(I) and Cu(II). According to Karlin KD. Et al., the varying redox properties of copper causes cellular damage by drilling holes in the cellular walls. The
According to Yoshida, Y. et. Al., copper ions can undergo Fenton-type reaction giving rise to reactive hydroxyl radicals, which can prove to be detrimental to cellular molecules.
In short, copper ions, Cu(I) and Cu(II), usually inhibit the respiration of the microbial particles by penetrating the cell. In addition to this, according to a study, the ions attack DNA – destroying it, making the transfer out of the question.
Historical shreds of evidence and a noble metal – Copper
Copper – as many Historians like to claim – might have been the first metal that became popular during ancient times. Artefacts, currency, jewellery, amulets, axes, tweezers, chisels, and so many other things depict that copper was indeed an important metal that coursed the line of development and the age came to be known as Copper age or chalcolithic. Not only the prosaic day-to-day stuff, but copper was also a symbol of elite and riches. In Europe, copper prestige goods such as crowns, and mace-heads was an indication of superlative class and high standards of people.
From the time immemorial, copper and its biocidal nature are known to humankind. Beneficial properties of copper might have been known to humanity since antiquity, although it is not clear if they were clear of the know-hows of the germ theory.
In a less likely known fact, Chinese ‘cash-coins’ were also believed to possess curative powers. Made from copper or bronze, Chinese cash coins were an integral part of traditional Chinese medicine and were used to treat conditions such as heart and stomach pain, bladder diseases, corneal opacity, fever and others.
For instance, Egyptians are known to use copper vessels to transport water and heal wounds even 5000 years back. During the outbreaks, people working in copper industries were less affected. Moreover, copper alloys were in extensive use as door handles, knobs, and taps, and other touch surfaces. However, the trend of using stainless steel and plastic rose in the late 20th century, which eliminated the copper form day-to-day use, and so did the rate of infectious disease and their transmission.
Foreseeable future: Self-sanitizing copper
Due to its lustrous appearance, stainless steel might add to the décor of the room; however; it fails to add any inherent antimicrobial benefits. Frequent sanitizing, cleaning, might look like an alternative to reduce the viral survival on these metals, but complete elimination is never possible. According to Carling PC, et. Al., only 25-50% of surfaces are routinely cleaned, and surface disinfection procedures in health care settings are frequently inadequate.
In a recent experiment, Sentara Leigh Hospital underwent a 10-month long clinical trial to evaluate the claims of biocidal properties of copper and its durability by switching to copper-impregnated touch surfaces and copper-infused products. For the experiment, copper-infused surfaces and linens were incorporated in 124 patient rooms, and results reported a 78 per cent overall reduction in multi-drug resistant organisms.
The notion of adapting self-sanitizing touch/hard surfaces is gaining recognition, thanks to experiments and researches. The decision of EPA to recognize copper and its alloys as an antimicrobial has managed to give ‘switch to copper idea’ the momentum it needed, however, implementation on an individual scale still seems like a distant yet imaginable future.