Correlative atomic-force microscopy and high-resolution scanning electron microscopy of proteins attached to platelet surfaces

Abstract

The atomic force microscope (AFM) has provided images at submolecular or atomic scale resolution of biological macromolecules attached to surfaces such as mica, graphite, or synthetic phospholipid membranes. Because the AFM can be operated with the sample in air, vacuum, or immersed in a liquid such as a biological buffer, it has the potential for high resolution imaging of the structure and organization of macromolecules on surfaces of cells in the hydrated or even living state. Realization of this potential would allow observation of molecular processes at the cell surface without the necessity for preparation of the sample for electron microscopy. To date, however, the AFM has yielded images of cell surfaces only at relatively low magnifications, and has not provided the atomic resolution achieved on hard, crystalline surfaces.Previously we have utilized correlative video-enhanced light microscopy, high voltage transmission electron microscopy, and low voltage, high resolution scanning electron microscopy (HRSEM)