Click-ExM enables expansion microscopy for all biomolecules

Expansion microscopy (ExM) allows super-resolution imaging on conventional fluorescence microscopes, but has been limited to proteins and nucleic acids. Here we develop click-ExM, which integrates click labeling into ExM to enable a 'one-stop-shop' method for nanoscale imaging of various types of biomolecule. By click labeling with biotin and staining with fluorescently labeled streptavidin, a large range of biomolecules can be imaged by the standard ExM procedure normally used for proteins. Using 18 clickable labels, we demonstrate click-ExM on lipids, glycans, proteins, DNA, RNA and small molecules. We demonstrate that click-ExM is applicable in cell culture systems and for tissue imaging. We further show that click-ExM is compatible with signal-amplification techniques and two-color imaging. Click-ExM thus provides a convenient and versatile method for super-resolution imaging, which may be routinely used for cell and tissue samples. Click-ExM uses click-chemistry-based labeling to increase the versatility of expansion microscopy. Click-ExM enables imaging of numerous classes of biomolecules including lipids, glycans, proteins, DNA, RNA and small molecules.

Automated summary

click-ExM integrates click labeling and fluorescent staining to enable nanoscale imaging of various biomolecules, such as lipids, glycans, proteins, DNA, RNA, and small molecules. It is applicable in cell culture systems and tissue imaging, and compatible with signal-amplification techniques and two-color imaging. Click-ExM provides a convenient and versatile method for super-resolution imaging.