ColorSTEM: An easy and convenient approach to Multicolor Electron Microscopy of Labeled Biological Specimens

Abstract

A new method for Multicolor Electron Microscopy (EM) using scanning transmission EM, ColorSTEM has been developed to increase the sensitivity, instrument availability and ease of use compared to that previously developed using electron energy loss spectroscopy and energy filtered transmission EM. Both methods paint multiple subcellular complexes with different colors, enabled by the localized and targeted deposition of diaminobenzidine (DAB) conjugated to different metals, which provides the differentiating signal from each other. With ColorSTEM, elastic scattering that is dependent upon atomic weight (Z-contrast) has far greater signals. Using deposited DAB with copper or gold to label subcellular components, Z-contrast imaging generates a pseudo-elemental map, resulting from differences in the grayscale of the conventional STEM images.