High-resolution molecular mapping by expansion-coupled label-free and multimodal imaging

Expansion microscopy enhances the effective spatial resolution of existing imaging techniques by physically enlarging the biological specimen rather than modifying the imaging hardware. This capability has enabled recent integration of sample expansion with various label-free imaging modalities, such as stimulated Raman scattering microscopy and mass spectrometry imaging. These approaches facilitate single-cell and subcellular molecular mapping, while enabling label-free and multimodal detection of complex chemical signatures inherent to the specimen. In this article, we review the coupling of expansion microscopy with label-free and multimodal imaging. We discuss both the advantages and challenges associated with this emerging approach and further provide perspectives on its future development and application to spatial biology studies.