Resolution doubling in light-sheet microscopy via oblique plane structured illumination

Structured illumination microscopy (SIM) doubles the spatial resolution of a fluorescence microscope without requiring high laser powers or specialized fluorophores. However, the excitation of out-of-focus fluorescence can accelerate photobleaching and phototoxicity. In contrast, light-sheet fluorescence microscopy (LSFM) largely avoids exciting out-of-focus fluorescence, thereby enabling volumetric imaging with low photobleaching and intrinsic optical sectioning. Combining SIM with LSFM would enable gentle three-dimensional (3D) imaging at doubled resolution. However, multiple orientations of the illumination pattern, which are needed for isotropic resolution doubling in SIM, are challenging to implement in a light-sheet format. Here we show that multidirectional structured illumination can be implemented in oblique plane microscopy, an LSFM technique that uses a single objective for excitation and detection, in a straightforward manner. We demonstrate isotropic lateral resolution below 150 nm, combined with lower phototoxicity compared to traditional SIM systems and volumetric acquisition speed exceeding 1 Hz. The longstanding goal of combining the optical sectioning of light-sheet illumination and the resolving power of multidirectional structured illumination microscopy is realized using an oblique plane microscope for improved fast 3D subcellular imaging.

Automated summary

Structured illumination microscopy (SIM) improves the spatial resolution of fluorescence microscopy, while light-sheet fluorescence microscopy (LSFM) avoids exciting out-of-focus fluorescence. By combining SIM with LSFM using oblique plane microscopy, high-resolution three-dimensional imaging with low phototoxicity can be achieved.