Photoelectron microscopy of cell surface topography.

Photoelectron micrographs of gold-palladium coated mouse 3T3 cells and chick embryo fibroblasts are presented. Since the gold-palladium suppresses differences in work function, the cell morphology seen in these micrographs is due to relief contrast. The heights of comparable cells were measured from the parallax present in transmission electron micrograph stereo-pairs of cell surface replicas. The origin of relief contrast and the effect of cell surface relief on the working depth of field in photoelectron images of cells are discussed. The micrographs demonstrate that photoelectron microscopy is very sensitive to fine details of cell surface topography, and that the working depth of field is not a limiting factor in the imaging of well-spread tissue culture cells.