University of Hong Kong researchers have developed the world’s first stainless steel that kills the Covid-19 virus.

The HKU team found that stainless steel containing high copper content can kill the coronavirus on its surface within hours, which they say could help lower risk of accidental infection.

The team from HKU’s Department of Mechanical Engineering and Centre for Immunity and Infection spent two years testing the addition of silver and copper content to stainless steel and its effect against Covid-19.

The novel coronavirus could remain on conventional stainless steel surfaces even after two days, posing “a high risk of virus transmission via surface touching in public areas,” the team said in the Chemical Engineering Journal.

The newly produced stainless steel with 20 percent copper can reduce 99.75 percent of Covid-19 viruses on its surface within three hours and 99.99 percent within six, the researchers found. It can also inactivate the H1N1 virus and E.coli on its surface.

“Pathogen viruses like H1N1 and SARS-CoV-2 exhibit good stability on the surface of pure silver and copper-contained stainless steel of low copper content but are rapidly inactivated on the surface of pure copper and copper-contained stainless steel of high copper content,” said Huang Mingxin, who led the research from HKU’s Department of Mechanical Engineering and Centre for Immunity and Infection.

The research team has attempted to wipe alcohol onto the surface of the anti-Covid-19 stainless steel and found that it does not change its effectiveness. They have filed a patent for the research findings which is expected to be approved within a year.

As copper content is spread equally within the anti-Covid-19 stainless steel, a scratch or damage on its surface would also not affect its ability to kill germs, he said.

Researchers have been liaising with industrial partners to generate prototypes of stainless steel products such as lift buttons, doorknobs and handrails for further tests and trials.

“The present anti-Covid-19 stainless steel can be mass produced using existing mature technologies. They can replace some of the frequently touched stainless steel products in public areas to reduce the risk of accidental infection and fight the Covid-19 pandemic,” Huang said.

But he said it is hard to estimate the cost and selling price of the anti-Covid-19 stainless steel, as it will depend on the demand as well as the amount of copper used in each product.

Leo Poon Lit-man, from HKU’s Centre for Immunity and Infection of the LKS Faculty of Medicine, who co-led the research team, said their research has not investigated the principle behind how high copper content could kill Covid-19.