Combination of a cryosectioning method and section scanning electron microscopy for immuno-scanning electron microscopy

We describe a novel immuno-scanning electron microscopy (SEM) technique that combines both Tokuyasu's cryosectioning and section SEM methods. In this technique, semithin cryosections, cut according to the Tokuyasu method, were adhered to glass microscope slides, immunostained for bio-molecules of interest and observed by confocal laser scanning microscopy. The same sections were subsequently embedded in epoxy resin and ultrathin sections were cut on an ultramicrotome. These were then observed by SEM using a backscattered electron detector. Correlation between immunofluorescence and SEM images was performed in the same area of the cryosection. Immuno-SEM was also performed using a FluoroNanogold-labeled secondary antibody. This novel immuno-SEM method can provide ultrastructural information of cell organelles in relation to associated molecules, such as Golgi- and ER-associated proteins. This novel immuno-SEM technique has the potential to be widely used.