FIG. 6.

Microtissues remain highly viable and functional after cryopreservation. (A) Brightfield and widefield fluorescence imaging of microtissues with encapsulated NIH 3T3, MDA-MB-231, and NHLF cells (nuclei shown in blue). Calcein AM (green) shows that all cell types had high viability (>83%) after 1 week of freezing and were over 90% viable after 1 week of culture in standard conditions, which was comparable to tissues that never underwent freezing. (B) Compaction of encapsulated cells indicated that before and after cryopreservation, cells were similarly contractile, compacting microtissues at similar rates and with the same trajectories. Shown with standard error and an average of 82 microtissues per condition. (C) Brightfield and widefield fluorescence imaging of cell proliferation after cryopreservation. Proliferative capacity, as determined with a Click-It EdU assay (nuclei shown in blue, proliferating cells in magenta). All microtissues in all conditions had cells that proliferated, indicating that cells retained their proliferative capacity after cryopreservation in the microtissues. All scale bars 100 μm. NIH 3T3, National Institute of Health 3T3. EdU, 5-ethynyl-2′-deoxyuridine. Color images available online at www.liebertpub.com/tec