Fig 1.
Example of (A) day 20 and (B) size-matched day 5 T47D spheroid. A dense center is visible in the day 20 spheroid. Day 20 spheroids were seeded from 1000 cells/ well and day 5 spheroids were seeded from 4000 cells/well to prepare size-matched samples.
Fig 2.
Mechanical characterization of T47D day 5 (Panel A) and day 20 (Panel B) was preformed using microtweezers. The average size of spheroids was 425 μm. Day 20 spheroids exerted higher force on the microcantilevers than day 5, size matched, spheroids.
Fig 3.
TEM images of a day 5 spheroid.
Cells in (a) outer and (b) inner regions show similar structures. Bar = 10 micrometers.
Fig 4.
TEM images of a day 20 spheroid.
Cells in (a) outer and (b) inner regions are compared. Inner regions show larger, closely-packed cells. Bar = 10 micrometers.
Fig 5.
TEM images stitched along the long axes of spheroids.
Manually traced shapes of cells. Cells indicated by dotted lines are incomplete cells only partially imaged.
Fig 6.
Analysis of a day 5 and day 20 spheroids TEM images.
Red areas are the inter space regions selected through the image processing program. The more closed-packed and tighter inner structure of Day 20 spheroids has been quantified.
Table 1.
Fig 7.
Viability assay of day 20 spheroids.
Dispersed cells showed 18% dead cells.