Molecular resolution imaging by post-labeling expansion single-molecule localization microscopy (Ex-SMLM)

Fabian U. Zwettler, Sebastian Reinhard, Davide Gambarotto, Toby D.M. Bell, Virginie Hamel, Paul Guichard, Markus Sauer

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19 Citations (Scopus)


Expansion microscopy (ExM) enables super-resolution fluorescence imaging of physically expanded biological samples with conventional microscopes. By combining ExM with single-molecule localization microscopy (SMLM) it is potentially possible to approach the resolution of electron microscopy. However, current attempts to combine both methods remained challenging because of protein and fluorophore loss during digestion or denaturation, gelation, and the incompatibility of expanded polyelectrolyte hydrogels with photoswitching buffers. Here we show that re-embedding of expanded hydrogels enables dSTORM imaging of expanded samples and demonstrate that post-labeling ExM resolves the current limitations of super-resolution microscopy. Using microtubules as a reference structure and centrioles, we demonstrate that post-labeling Ex-SMLM preserves ultrastructural details, improves the labeling efficiency and reduces the positional error arising from linking fluorophores into the gel thus paving the way for super-resolution imaging of immunolabeled endogenous proteins with true molecular resolution.

Original languageEnglish
Article number3388
Number of pages11
JournalNature Communications
Issue number1
Publication statusPublished - 1 Dec 2020

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