Abstract

Imaging of multicellular tumor spheroids (MCTS) is of high relevance since MCTS recapitulate tumor environment characteristics more closely compared to 2D cell cultures. In particular, fluorescence microscopy imaging after DNA staining by DAPI allows observation of cell nuclei in MCTS. Limited depth-of-field (DOF) however affects the capability of visualizing the whole sample all-in-focus in a single shot. In order to overcome limited DOF while achieving 3D visualization of MCTS a custom-built fluorescence microscope including an electrically focus-tunable lens was developed. Once the multifocus sequence is acquired, image registration is applied in order to correct for changes in the field of view between images of the stack. Then post-processing in Fourier domain of the z-stack allows for DoF extension along with synthesis of novel viewpoints from which a 3D visualization of the MCTS can be reconstructed.

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