Lattice Light Sheet Microscope (LLSM)

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One major goals of light microscopy is to analyze the dynamic behavior of molecular and cellular networks under physiological conditions. The technical obstacles in achieving this goal has always been the simultaneous pursuit of imaging depth, speed, spatial resolution and specimen viability. The development of light sheet microscopy, which couples a separate excitation lens in perpendicular axis to the detection lens, has made it possible to confine the excitation of the specimen only to the volume being observed. This reduced phototoxicity significantly and simultaneously increased the image acquisition speed through its wide-field light collection mode.However, the diffracting Gaussian beam used for the light sheet in common systems imposed limits on the optical resolution that could be achieved. This limitation was overcome by introducing a non-diffracting Bessel beam in light sheet microscopy (1). The further improved ‘lattice light sheet microscope’ (LLSM) generated an ultrathin light sheet (~ 400 nm) improving the axial resolution and allowing for very fast volumetric imaging (2). Importantly, the LLSM caused significantly less photodamage compared to commonly used methods for 3D high-resolution live-specimen imaging (i.e. spinning disk confocal). The LLSM is thus a novel tool to analyze fast 3D sub-cellular dynamics in cells or small organisms with high SNR and low photodamage. Recent applications of the LLSM have successfully visualized and quantified sub-cellular processes with unprecedented details and imaging volumes (i.e. (2–6)). The optional LLS-SIM (structured illumination microscopy) mode or the combination of LLSM with single molecule localization microscopy offer super-resolution applications with spatial resolutions beyond the diffraction limit (2, 7).With this proposal we aim at establishing the first commercially available LLSM in Germany within the centrally located Advanced Medical Bioimaging core facility of the Charité – Universitätsmedizin Berlin (AMBIO). This way we ensure that the LLSM will be accessible to all academic researchers, maintained by experts, and that the researchers receive professional training and assistance to pursue their biological applications. The high-profile research projects within the Berlin research community (listed in 2.5) all require fast, 3D live-specimen imaging with low phototoxicity and would greatly benefit from the LLSM. Three of these groups have already used an early version of the LLSM with very promising results from cultured cells and living brain. Beyond these projects, about 30% of the usage time will be available for any other research group with suitable LLSM projects within the German research community. We will publish an annual report about the performance (and limitations) of the LLSM to help the research community in evaluating whether this novel method would be suitable for their project.