Versatile high-speed volumetric imaging from microscopic to macroscopic scale by self-adaptive oblique plane microscopy

There is an increasing need for large-scale high-speed volumetric recording in complex multi-cellular model systems to define dynamic processes. Oblique plane microscopy (OPM) provides a solution that features oblique illumination, rapid optical scanning, and remote focusing to achieve real-time 4D microscopy. OPM implements light sheet imaging via a single primary objective lens, making the entire space below the objective accessible for large specimens, such as living mouse brain. Yet it is challenging to adopt OPM beyond a microscopic scale (i.e. size < 1 mm), limiting its broad applications. Here we present a self-adaptive OPM that leverages Abbe's sine condition to unlock its flexibility across a range of field-of-views (FOVs) (up to 8 mm 2 ) and resolutions (down to 2.2 µm 3 ). This versatility enables brain-wide single neuron volumetric calcium imaging in behaving larval zebrafish (1×0.4 mm 2 FOV at 5 Hz) and capillary blood cell tracking in living mouse brain (>3×3 mm 2 FOV) with a sweeping 0.32 mm wide volume section at 100 Hz. In optically cleared mouse brain, the flexibility allows a screen-and-zoom capability by sequentially imaging the whole brain at low-and-high magnifications to locate and resolve subcellular structures such as dendritic tress and spines. By offering a switchable imaging resolution, volume, and speed, the self-adaptive OPM achieves a versatile platform for studying a wide range of multi-cellular model system, whether in vivo or fixed and optically cleared.