The development of new cancer treatments and the early prediction of their therapeutic potential are often made difficult by the lack of predictive pharmacological models. The 3D multicellular tumor spheroid (MCTS) model offers a level of complexity that recapitulates the three-dimensional organization of a tumor and appears to be fairly predictive of therapeutic efficiency. The use of spheroids in large-scale automated screening was recently reported to link the power of a high throughput analysis to the predictability of a 3D cell model. The spheroid has a radial symmetry; this simple geometry allows establishing a direct correlation between structure and function. The outmost layers of MCTS are composed of proliferating cells and form structurally uniform domain with an approximate thickness of 100 microns. The innermost layers are composed of quiescent cells. Finally, cells in the center of the spheroid can form a necrotic core. This latest region is structurally heterogeneous and is poorly characterized. These features make the spheroid a model of choice and a paradigm to study the optical properties of various epithelial tissues. In this study, we used an <i>in-vitro</i> optical technique for label-free characterization of multicellular systems based on the index- mismatch induced spherical aberrations. We achieve to monitor and characterize the optical properties of MCTS. This new and original approach might be of major interest for the development of innovative screening strategies dedicated to the identification of anticancer drugs.
Supercontinuum laser sources provide a very useful tool to characterize materials and scattering media such
as nanomaterials in suspensions, aerosols or paint coatings. Onera, The French Aerospace Lab, has developed
a fast, in-line and comprehensive optical characterization method. The hyperspectral polarized angular light
measurements by tumor cells exhibit a unique signature. We propose an original way to probe tumor cells in
in-vitro samples. First experimental results are presented with potential applications. This is the first time in
our knowledge that hyperspectral, polarimetric and angular signature of MCTS is reported.