Strategy and tactics in electron microscopy of cell surfaces

The study of cell surfaces has evolved with new imaging techniques over the past decade. Researchers have sought methods to preserve native structures while visualizing surfaces at high resolution. Established knowledge shows that freeze-drying and critical point drying are effective for surface replicas. However, no single method satisfies all requirements for structure preservation and antigenicity. Scanning electron microscopy offers a broader view of the cell and larger sample sizes for statistical analysis. Cleaving techniques have been developed to study plasma membrane-associated structures like the cytoskeleton. These methods aim to address biological questions related to membrane particles and glycocalyx interactions. This gap motivated the development of new procedures for cytoskeleton/membrane studies.

The purpose of this review is to evaluate various electron microscopy techniques for cell surface visualization. The goal is to determine which methods best preserve native structures and antigenicity. The study addresses the challenge of finding a universal technique suitable for all cell surfaces. Researchers aim to compare freeze-drying, critical point drying, and scanning electron microscopy. The focus is on cell monolayers, though some methods apply to cells in suspension. The review also considers cleaving techniques for dorsal and ventral membrane studies. The authors seek to guide experimenters in selecting the most appropriate method for their specific project. The aim is to highlight the strengths and limitations of each technique.

The study employs surface replicas of freeze-dried or critical point-dried cells for high-resolution imaging. Scanning electron microscopy is used to visualize the whole cell and provide statistical data. Cleaving techniques are applied to study cytoplasmic domains and membrane structures. Lysis-squirting is used for protoplasmic surfaces of ventral membranes. Dry- or wet-cleaving is used for dorsal membranes and cytoplasmic domains. New procedures are developed for cytoskeleton/membrane interactions and intramembrane particle identification. The methods are evaluated for their suitability in different biological contexts. The review emphasizes the importance of selecting the right method based on the project's goals.

Surface replicas of freeze-dried cells are best for high-resolution studies and gold immunolabelling. Scanning electron microscopy provides a broader view and larger sample size for statistical evaluation. Cleaving techniques are useful for studying plasma membrane-associated structures like the cytoskeleton. Lysis-squirting is most suitable for protoplasmic surfaces of ventral membranes. Dry- or wet-cleaving is a useful alternative for dorsal membranes and cytoplasmic domains. New procedures have been developed for cytoskeleton/membrane interactions and intramembrane particle identification. The assessment shows no single method satisfies all requirements. The choice of method depends on the specific aims of the project.

The authors conclude that no single method satisfies all requirements for cell surface visualization. They recommend a multi-methodical approach when one method does not provide satisfactory results. The choice of method should be based on the specific aims of the project. Surface replicas of freeze-dried cells are best for high-resolution imaging. Scanning electron microscopy is suitable for whole-cell visualization and statistical analysis. Cleaving techniques are useful for studying cytoplasmic domains and membrane structures. Lysis-squirting is recommended for protoplasmic surfaces of ventral membranes. Dry- or wet-cleaving is a useful alternative for dorsal membranes and cytoplasmic domains.