Organisms are three dimensional and the spatial organisation of cells in a tissue is essential for its proper function. Classical 2D cell cultures can therefore be inadequate as model systems.
In recent years 3D organotypic culture models and multicellular tumor spheroids have gained popularity as tools for research, drug discovery and toxicity studies. Several studies have shown the benefit of such models over 2D culture.
Due to their size, 3D tissues pose characteristic challenges to any imaging system but benefit greatly from confocal imaging. As the sample is thick compared to the focal depth of the lens, spinning disk confocal systems perform better when the pinhole distance has been increased to minimize pinhole crosstalk, as is the case for the Opera Phenix™ HCS system.
As 3D tissues are grown in aqueous media, the image quality is greatly improved when using water immersion lenses.