High-resolution scanning electron microscopy of bacteriophages 3C and T4.

An account is presented of the design and operation of a new scanning electron microscopic, and its first application to the study of biological samples. Bacteriophages were chosen because much of their ultrastructure is beyond the resolution of the conventional scanning electron microscope. The new instrument permits examination of bulk samples with a resolution that exceeds, by at least a factor of 2.5, the resolution obtained in the best secondary electron scanning electron microscopes using high brightness guns, and exceeds by an order of magnitude the resolution of standard scanning electron microscopes using tungsten filament guns. It also permits examination of biological samples in scanning transmission mode at resolutions similar to conventional transmission electron microscopes.