by Keyword: correlative light and electron microscopy

Andrian T, Delcanale P, Pujals S, Albertazzi L, (2021). Correlating Super-Resolution Microscopy and Transmission Electron Microscopy Reveals Multiparametric Heterogeneity in Nanoparticles Nano Letters 21, 5360-5368

The functionalization of nanoparticles with functional moieties is a key strategy to achieve cell targeting in nanomedicine. The interplay between size and ligand number is crucial for the formulation performance and needs to be properly characterized to understand nanoparticle structure-activity relations. However, there is a lack of methods able to measure both size and ligand number at the same time and at the single particle level. Here, we address this issue by introducing a correlative light and electron microscopy (CLEM) method combining super-resolution microscopy (SRM) and transmission electron microscopy (TEM) imaging. We apply our super-resCLEM method to characterize the relationship between size and ligand number and density in PLGA-PEG nanoparticles. We highlight how heterogeneity found in size can impact ligand distribution and how a significant part of the nanoparticle population goes completely undetected in the single-technique analysis. Super-resCLEM holds great promise for the multiparametric analysis of other parameters and nanomaterials.

JTD Keywords: cellular uptake, correlative light and electron microscopy (clem), density, electron microscopy (em), functionalization, heterogeneity, nanomedicine, nanoparticles, pegylation, plga, progress, quantification, size, Correlative light and electron microscopy (clem), Electron microscopy (em), Heterogeneity, Nanomedicine, Nanoparticles, Physicochemical characterization, Super-resolution microscopy (srm)

Andrian T, Bakkum T, van Elsland DM, Bos E, Koster AJ, Albertazzi L, van Kasteren SI, Pujals S, (2021). Super-resolution correlative light-electron microscopy using a click-chemistry approach for studying intracellular trafficking Methods In Cell Biology 162, 303-331

© 2020 Elsevier Inc. Correlative light and electron microscopy (CLEM) entails a group of multimodal imaging techniques that are combined to pinpoint to the location of fluorescently labeled molecules in the context of their ultrastructural cellular environment. Here we describe a detailed workflow for STORM-CLEM, in which STochastic Optical Reconstruction Microscopy (STORM), an optical super-resolution technique, is correlated with transmission electron microscopy (TEM). This protocol has the advantage that both imaging modalities have resolution at the nanoscale, bringing higher synergies on the information obtained. The sample is prepared according to the Tokuyasu method followed by click-chemistry labeling and STORM imaging. Then, after heavy metal staining, electron microscopy imaging is performed followed by correlation of the two images. The case study presented here is on intracellular pathogens, but the protocol is versatile and could potentially be applied to many types of samples.

JTD Keywords: cells, click-chemistry, complex, correlative light and electron microscopy, cycloaddition, ligation, localization, proteins, resolution limit, single molecule localization microscopy, stochastic optical reconstruction microscopy (storm), storm, super-resolution microscopy, tokuyasu cryo-sectioning, tool, Click-chemistry, Correlative light and electron microscopy, Fluorescent-probes, Single molecule localization microscopy, Stochastic optical reconstruction microscopy (storm), Super-resolution microscopy, Tokuyasu cryo-sectioning, Transmission electron microscopy