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[KH Explains] How effective are antimicrobial films on elevator buttons?

Chemists, business operators and government authorities weigh efficacy

An antimicrobial film covers elevator buttons in Seoul (Lim Jeong-yeo/The Korea Herald)
An antimicrobial film covers elevator buttons in Seoul (Lim Jeong-yeo/The Korea Herald)
Transparent film covering surfaces in public areas such as elevator buttons have become a common sight in South Korea throughout the COVID-19 crisis.

Containing ionized copper, these films assert to be antimicrobial and effective at deflecting fomite transmission of SARS CoV-2 virus.

The films have become nearly imperative for people as they go about their lives pressing elevator buttons, pushing grocery shopping carts or tapping automated kiosks at take-out restaurants. The Seoul Housing & Communities Corporation for one has equipped a total of 1,421 elevators with antimicrobial films at the buildings it operates.

But despite these films becoming increasingly omnipresent, the question remains: do they really do the trick?

Copper, the first metal Homo sapiens mastered, was recognized as the first metallic antimicrobial agent by the American Environmental Protection Agency in 2008.

Copper ions enter the systems of bacteria and viruses under the pretense of being an essential nutrient and then debilitate them at the molecular level. The knowledge of copper and copper alloys as disinfectants dates back to ancient times, for the case of the chemical element in metal form.

Does the same mechanism apply to plastic films containing copper? Recent arguments from local chemists claim that many of these purported antimicrobial films are bogus.

“Copper is either vividly red or blue. If these films contained enough copper to be of any use against a virus, they could not be so transparent as to show the object on the opposite side,” claimed Lee Duck-hwan, honorary professor of Chemistry at Sogang University in Seoul.

“And if ionized copper is entrapped between plastic sheets, then what people touched would be plastic -- not copper,” said Lee.

According to a study published in the New England Journal of Medicine on April 16, SARS-CoV-2 could remain on plastic for 72 hours; 48 hours on stainless steel; 24 hours on cardboard; and 4 hours on copper.

It could also remain in the air for 3 hours, albeit progressively less infectious over time.

The Korea Consumer Agency has yet to investigate antimicrobial films. A KCA official told The Korea Herald that the institute only acts upon reports of specific damage cases against consumers.

Likewise, no government authorities have yet to give official approva to any antimicrobial films in the market.

Generally, the Commerce, Drugs and Environment ministries would collaborate on testing and regulating products. However, it has yet to be decided which ministry should take the lead when it comes to antimicrobial films.

The biggest step has been taken by the Environment Ministry, where a team in the chemical products monitoring department is carrying out tests to discern the harmfulness and effectiveness of 38 antimicrobial film products.

“These films are a direct byproduct of COVID-19. They are completely new and the process of evaluating such products usually requires a year. We’re expecting to learn the results of our tests by the end of the yer,” said an Environment Ministry official responsible for the evaluation.

It is premature to determine whether the Environment Ministry is the accountable government body for antimicrobial films as the product is ambiguous to categorize, the official said. Government agencies will have to negotiate the details to designate the most relevant and available department to assign the responsibility for continuous monitoring in the future.

The official couldn’t say for certain as of yet whether the films that were undergoing tests had true antimicrobial qualities.

All the while, the newfound area of business is prompting some to target overseas markets, with some of them leveraging original technologies.

Copper Medical Team is a Korean company that has been exporting its patented antimicrobial films to the US and South America since August.

“We are shipping two 40-feet containers every month to Chile and other South American nations,” said Park Young-jo, CEO of CMT.

CMT says that its film uses a unique nano copper technology. By downsizing the copper molecules, CMT claims it is able to more evenly and densely coat the films with copper, Park said.

As the polyethylene plastic film meets the copper, the color naturally fades to a yellowish hue, Park explained, adding that it’s not how much copper that goes in to the film that matters but how much of it can get out while in use.

CMT’s film, for example, has fine chippings on it, making microscopic holes for the ionized copper to breathe through.

By Lim Jeong-yeo (kaylalim@heraldcorp.com)
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