Journal of Histochemistry & Cytochemistry 61(3) 236 –247 © The Author(s) 2013 Reprints and permission: sagepub.com/journalsPermissions.nav

By combining the strengths of two imaging modalities on a single sample, correlative microscopy has proven to be extremely valuable for research in the field of cell biology. The fluorescence microscope (FM) allows for live cell imaging and, furthermore, for the localization of the region of interest (ROI) over a large field of view. The transmis-sion electron microscope (TEM) has an unprecedented res-olution and is not limited to imaging of just the probe but also the cellular context. Therefore, by combining the FM and TEM in the analysis of a sample, cell biology research is reaching new heights. Correlative microscopy, however, also poses serious challenges. The structure or ROI identified with the FM needs to be traced back in the TEM, which is a difficult and time-consuming process. The next hurdle for correlative microscopy lies in the preparation of the specimen. The FM demands samples to be labeled with a fluorescent probe. With exception of cryo-electron microscopy, TEM imaging requires the biological specimen to be contrasted with heavy metal salts. When the fluorophore is in close proxim-ity to the heavy metal stain, its fluorescence is quenched (Karreman et al. 2009; Valeur 2002). To overcome this, additional sample preparation steps need to be carried out in between imaging the sample with the FM and the TE