engleski

Composition of spheroids formed by magnetic levitation

Ball shaped cellular structures called spheroids are the basis of 3D cell culture. Shift from 2D to 3D cell culture was necessary in various fields since 3D structures mimic live tissue better. There are many different ways to form spheroids from single cells. One of the methods is magnetic levitation where cells are grown under the influence of a magnetic field after taking up ferrous nanoparticles. Spheroids formed this way are well defined and compact. Our work set out to establish the baseline composition of these spheroids to better characterize them for further use in toxicity assays. Spheroids in question were formed from glioblastoma cells (namely D54 cell line) by magnetic levitation. They were formed and grown for up to 15 days prior to analysis with the growth media changed as needed. Completely grown spheroids were harvested and dissolved in 0.5% trypsin before staining with Annexin and PI. Samples were analyzed by flow cytometry to determine the ratio of live, apoptotic and necrotic cells in the samples. Additional samples were frozen, cryostat cut and stained to observe changes in morphology and collagen production. Results showed that the ration changes over time with spheroids of different size having different proportions of apoptotic and live cells, but relatively constant number of necrotic cells. The ratio of apoptotic and live cells rises and falls respectively during the growth period. The intent is to determine how spheroids behave in control conditions as to better interpret toxicity results. Longer growth time resulted in bigger, less compact spheroids that show beginnings of ECM synthesis.

magnetic levitation, spheroids, apoptotic ratio

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