Scanning Tunneling and Atomic Force Microscopy of T4 Bacteriophage and Tobacco Mosaic Virus

Abstract
Bacteriophage T4 and tobacco mosaic virus were imaged by scanning tunneling microscopy after metal coating of the specimens and by atomic force microscopy without coating, and their topographies were examined. A metal coating approximately 5 nm in thickness assured easy and reproducible imaging of samples but obscured their detailed structural features. AFM gave a better resolution on this scale, revealing the presence of tail fibers 2 nm in diameter of T4 phage, which is the best resolution so far reported for isolated biological structures. Sample topographies were in good agreement with the results of previous electron microscopic analysis.