Artifacts in Gold Shadowed Electron Micrographs Due to Electrons of High Intensity

Abstract

Electron micrographs of gold shadow-cast specimens of tobacco mosaic virus show that artifacts, consisting of segmented or even globular particles, are formed when the specimen is exposed to the beam of electrons at high intensity. It is suggested that these are caused by the thin film of gold becoming fluid and forming globules on the surface of the virus rods and supporting membrane. Tobacco mosaic-virus not treated with gold did not show any change after having been subjected to the same treatment. The results indicate that gold-covered specimens should not be subjected to prolonged exposure to an electron beam of high intensity.