Atomic force microscopy has been used to probe the surface nanostructures of severe acute respiratory syndrome coronavirus (SARS‐CoV). Single crown‐like virion was directly visualized and quantitative measurements of the dimensions for the structural proteins were provided. A corona of large, distinctive spikes in the envelope was measured after treatment with hydroxyoctanoic acid. High‐resolution images revealed that the surface of each single SARS‐CoV was surrounded with at least 15 spherical spikes having a diameter of 7.29 ± 0.73 nm, which is in close agreement with that of S glycoproteins earlier predicted through the genomes of SARS‐CoV. This study represents the first direct characterization of the surface ultrastructures of SARS‐CoV particles at the nanometre scale and offers new prospects for mapping viral surface properties.
Surface ultrastructure of SARS coronavirus revealed by atomic force microscopy