Researchers at Ruhr-University Bochum investigated ways to make copper and silver release even more ions than they normally would as a result of corrosion, a process that helps prevent the growth of bacteria or kill them completely.
The effectiveness of such sacrificial anode systems against bacteria has already been demonstrated. However, whether viruses can also be rendered harmless in this way has not yet been investigated in detail.
“This is why we analysed the antiviral properties of surfaces coated with copper or silver as well as various silver-based sacrificial anodes, and also examined combinations of copper and silver with regard to possible synergistic effects,” virologist Stephanie Pfänder said.
The team compared the effectiveness of these surfaces against bacteria with the effectiveness against viruses.
Surfaces with sacrificial anode effect, especially nanopatches consisting of silver and platinum as well as the combination of silver and copper, efficiently stopped bacterial growth.
Yet, a different picture emerged with SARS-CoV-2: thin copper layers significantly reduced the viral load after only one hour. On the other hand, sputtered silver surfaces had only a marginal effect, and silver nanopatches did not impress the virus either.
“In conclusion, we demonstrated a clear antiviral effect of copper-coated surfaces against SARS-CoV-2 within one hour, while silver-coated surfaces had no effect on viral infectivity,” Pfänder said.