Superresolution microscopy for bioimaging at the nanoscale: from concepts to applications in the nucleus

Superresolution microscopy breaks the diffraction limit of light, making it possible to visualize a broad range of subcellular components with nearly molecular scale detail. The potential of this powerful tool is continuously growing since the implementation of optical config urations and data analyses compatible with the technically challenging, yet frequent in biology, thick and crowded samples. We review the principles underlying stimulated emission depletion, structured illumination, and single-molecule localization microscopy approaches, and their technical developments, with an emphasis on three-dimensional and live-cell imaging. Special attention is brought to the new requirements for probe efficiency, namely their size and their photophysical properties. Finally, recent applications exploring the interphase nucleus are described to illustrate the performance of superresolution techniques.