Scanning electron microscopy of the undersurface of cell monolayers grown on metallic implants

When cells, cultured on a plastic disc, are fixed, dehydrated and embedded in acrylic resin their undersurfaces can be studied by scanning electron microscopy after the disc has been separated and removed from the resin, using a sharp knife, and the resin etched away using glow discharge before sputter coating the now exposed cell undersurface with gold. This method does not work for metallic discs, which do not separate cleanly, leaving the cells in the resin attached to the metal. Rapid cooling of the discs on an aluminium block cooled with nitrogen slush was found to be a successful method, leaving no resin on the metal and without any observable morphological damage to the cells in the resin block. This then allowed direct adhesion studies with the SEM, on the cells' undersurfaces. Focal adhesion processes and stress fibres were observed, which were related to the cell's adhesion and shape.