Optical Coherence Tomography Detects Necrotic Regions and Volumetrically Quantifies Multicellular Tumor Spheroids

Abstract

Three-dimensional (3D) tumor spheroid models have gained increased recognition as important tools in cancer research and anti-cancer drug development. However, currently available imaging approaches employed in high-throughput screening drug discovery platforms e.g. bright field, phase contrast, and fluorescence microscopies, are unable to resolve 3D structures deep inside (>50 µm) tumor spheroids. In this study, we established a label-free, non-invasive optical coherence tomography (OCT) imaging platform to characterize 3D morphological and physiological information of multicellular tumor spheroids (MCTS) growing from ~250 µm up to ~600 µm in height over 21 days. In particular, tumor spheroids of two cell lines glioblastoma (U-87 MG) and colorectal carcinoma (HCT 116) exhibited distinctive evolutions in their geometric shapes at late growth stages. Volumes of MCTS were accurately quantified using a voxel-based approach without presumptions of their geometries. In contrast, conventional diameter-based volume calculations assuming perfect spherical shape resulted in large quantification errors. Furthermore, we successfully detected necrotic regions within these tumor spheroids based on increased intrinsic optical attenuation, suggesting a promising alternative of label-free viability tests in tumor spheroids. Therefore, OCT can serve as a promising imaging modality to characterize morphological and physiological features of MCTS, showing great potential for high-throughput drug screening.

Facile Tumor Spheroids Formation in Large Quantity with Controllable Size and High Uniformity

“…Details of the configuration of the spectral domain OCT employed in 3D tumor spheroid imaging can be found in ref. 27 . An individual tumor spheroid was placed in a petri-dish under the objective of the OCT system.…”

3D Culture Histology Cryosectioned Well Insert Technology Preserves the Structural Relationship between Cells and Biomaterials for Time‐Lapse Analysis of 3D Cultures

“…Other in vivo imaging technologies such as ultrasound, computed tomography, magnetic resonance imaging, optical coherence tomography, and light sheet microscopy are unfortunately not easily adaptable for cell culture plates. The better‐suited confocal and multiphoton microscopes provide sufficient data but they cannot be performed with histology.…”

Optical Imaging Approaches to Monitor Static and Dynamic Cell‐on‐Chip Platforms: A Tutorial Review

“…Fourier transforming of the spectra results in the depth profile. The system is useful for characterizing 3D morphological and physiological information of multicellular tumor spheroids . A fast and point by point scanning of a focused light beam on a sample followed by a successive image processing is a technical challenge of this imaging approach per se.…”