SARS-CoV-2 is primarily spread through respiratory particles in the air, but many health officials also recommend disinfecting surfaces as another measure to reduce transmission. While this may seem like common sense advice, the exact risks of SARS-CoV-2 surface transmission are not yet fully understood. A new study conducted through the National Virtual Biotechnology Laboratory, a consortium of Department of Energy (DOE) laboratories focused on COVID-19 response, offers new insight into the interactions between SARS-CoV-2 and inorganic surfaces, which could lead to new strategies for minimizing exposure.
The research team leveraged instrumentation from the Environmental Molecular Sciences Laboratory, a DOE Office of Science user facility housed at Pacific Northwestern National Laboratory (PNNL). Specifically, the researchers used atomic force microscopy (AFM) paired with scattering-type scanning near-field optical microscopy (s-SNOM) to measure the adhesion forces between the SARS-CoV-2 spike protein and materials including copper, iron, aluminum, silica, ceria and metallic gold. S-SNOM was utilized to chemically identify and isolate the locations of spike proteins at nanoscale prior to AFM examination, which was performed using tips coated with the different inorganic surface materials.
The team found that the adhesion was strongest between the spike protein and metallic gold—about 10 times stronger than with the other materials tested. The researchers stated this is most likely due to gold’s high affinity for water, which would cause a stronger capillary force between the protein and layer of water on the tip when performing the experiments at ambient temperature and humidity. Additionally, the protein adhesion to the other materials was non-specific to the properties of metal oxide surfaces, suggesting that water capillary force is the main driver of the virus’ adhesion to inorganic surfaces. This study was published in the American Chemical Society journal Langmuir.
The findings of this research could help inform disinfection strategies and lead to the development of new tools such as air filters and antiviral surface coatings to reduce the risk of surface transmission of SARS-CoV-2 and other similar viruses.
Photo: A multi-institutional team used atomic force microscopy (AFM) to obtain information about nanoscale interactions between the spike protein of SARS-CoV-2 and common household inorganic surfaces. Credit: Illustration by Michael Perkins, Pacific Northwest National Laboratory