Microporous Copper Excels at Killing Bacteria
Copper and copper-alloy surfaces have been shown to kill a number of microorganisms including MRSA, E-coli 0157:H7, Clostridium difficile, influenza A virus, adenovirus and fungi.
The novel coronavirus causing COVID-19 pandemic survives for days on glass and stainless steel but dies within hours after landing on copper. (2)
In spite of these good results, a recent report from Australia highlights further improvements. RMIT Melbourne University professor Ma Qian says;
“A standard copper surface will kill about 97 percent of golden staph within four hours. Incredibly, when we placed golden staph bacteria on our specially designed copper surface, it destroyed more than 99.99 percent of the cells in just two minutes. So not only is it more effective, it’s 120 times faster.” (3)
The study’s lead author, Dr. Jackson Leigh Smith, said the copper’s unique porous structure was key to its effectiveness as a rapid bacteria killer.
A special copper mold casting process was used to make the alloy, arranging copper and manganese atoms into specific formations
The manganese atoms were then removed from the alloy using a cheap and scalable chemical process called ‘dealloying,’ leaving pure copper full of tiny microscale and nanoscale cavities in its surface.
“Our copper is composed of comb-like microscale cavities and within each tooth of that comb structure are much smaller nanoscale cavities; it has a massive active surface area. The pattern also makes the surface super hydrophilic, or water loving, so that water lies on it as a flat film rather than as droplets,” Smith said
“These combined effects not only cause structural degradation of bacterial cells, making them more vulnerable to the poisonous copper ions, but also facilitates uptake of copper ions into the bacterial cells,” Smith added. (1)
There could be a huge range of applications for the material including antimicrobial door handles and other touch surfaces in schools, hospitals, homes and public transport, as well as filters in antimicrobial respirators or air ventilation systems.
References
1. J. L. Smith et al, “Robust bulk micro-nano hierarchical copper structures possessing exceptional bacterial efficacy,” Biomaterials, 280, January 2022, 121271
2. Jim Morrison, “Copper’s virus killing powers were known even to the ancients”, smithsonianmag.com, April 14, 2020
3. RMIT University, “New copper surface eliminates bacteria in just two minutes,”, sciencedaily.com, December 13, 2021
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K Kaiser
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Hello Jack,
A thin coating of that copper with silver might even work better in killing bacteria and virus.
Cheers,
KK
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Roslyn Ross
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Let us deal with the reality that the problem exists because greed-driven science-medicine has encouraged the abuse of antibiotics in grossly irresponsible ways.
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