Light-sheet fluorescence microscopy (LSFM) has established itself as an irreplaceable imaging technique in developmental biology over the past two decades. With its emergence, the extended recording of in toto datasets of developing organisms across scales became possible. Remarkably, LSFM opened the door to new spatio-temporal domains in biology, offering cellular resolution on the one hand, and temporal resolution on the order of seconds on the other hand. As in any fluorescence microscopy technique, LSFM is also affected by image degradation at greater tissue depths. Thus far, this has been addressed by the suppression of scattered light, use of fluorophores emitting in the far red spectrum, multi-view detection and fusion, adaptive optics, as well as different illumination schemes. In this work, I investigate for the first time in vivo optical aberration reduction via refractive index matching in LSFM. Examples are shown on common model organisms as Arabidopsis thalina, Oryzias latipes, Mus musculus, as well as Drosophila. Additionally, I present a novel open-top light-sheet microscope, tailored for high-throughput imaging of mammalian samples, such as early stage mouse embryos. It is based on a
three objective geometry, encompassing two opposing detection objective lenses with high light collection efficiency, and an invertedly mounted illumination lens. It bridges the spatial scale between samples by employing an extendible light-sheet illumination via a tunable acoustic gradient index lens. Both parts of this work improve the image quality across the 3D volume of specimens, paving the way for more quantitative recordings at greater tissue depths
