The material a surface is made of affects how long viruses and bacteria can remain contagious on it. (RUB, Marquard)

Silver and copper ions wipe out many pathogens. That’s why implants and medical instruments, for example, are coated with these metals. Researchers have studied whether these metals can also help contain the COVID-19 pandemic by rendering Sars-Cov-2 harmless. They showed that a copper coating eliminates the virus. But the same is not true for silver.

As a result of corrosion, copper and silver release positively charged ions into their environment, which are harmful to bacteria in several ways and prevent their growth or kill them completely. This effect has long been exploited, for example by coating implants with these metals to prevent bacterial infections. There are some tricks that can be employed to release even more ions and intensify this effect.

For example, the team uses a so-called sputtering system with which the thinnest layers or tiny nanopatches of the metals can be applied to a carrier material. Depending on the sequence or quantity in which the individual metals are applied, different surface textures are created. If a precious metal such as platinum is also applied, silver corrodes even faster and releases more antibacterial ions.

However, whether viruses can also be rendered harmless in this way has not yet been investigated in detail. The team compared the effectiveness of these surfaces against bacteria with the effectiveness against viruses.