Advancements in Light-Sheet Fluorescence Microscopy for Three Dimensional Cellular Spheroid Imaging

The dynamics of cell biology have always been an active area of research. To visualize and quantify this complex cellular process <i>in vivo</i>, we need optics with a high spatiotemporal resolution. The advancement in optics and image acquisition techniques has revolutionized the field of microscopy. Light-sheet fluorescence microscopy is one of the most advanced imaging tools, which offers a good spatiotemporal resolution, fast imaging, and less phototoxicity to a sample when compared with conventional microscopy techniques. Cell culture techniques have evolved from traditional two-dimensional planar cultures to three-dimensional cultures in the form of spheroids. Spheroid culture truly mimics physiological conditions due to better cell-to-cell and cell-to-matrix interactions within the spheroids. Spheroids have been extensively studied as a model for drug screening, cancer biology, and regenerative medicine. However, the opacity of the core within spheroids restricts its imaging through conventional microscopy. Light-sheet fluorescence microscopy proves to be an effective tool to overcome this problem, as it provides a suitable combination of deep penetration with an ultralow intensity of excitation light, thereby reducing the photobleaching of spheroids. Over the period of years, the light-sheet microscopy technique underwent many modifications, such as adaptive optics and the integration of artificial intelligence and machine learning modules based on its design and applications. Therefore, the present review will focus on the development of the light-sheet microscopy technique, its advancements, application for spheroid imaging, and will also explore the futuristic development trajectory for this technique.