Figure 1.
(a) Cross sections of spheroids of HT29 cells for zero external pressure (left) and pressure Pext = 10 kPa (right) with DAPI-stained nuclei. (b) Average internuclear distance as a function of radial distance r from the centre for spheroids of HT29 cells after growth during 4 days (circles). The internuclear distance as a function of r is shown 5 min (squares) and 1 day (triangles) after a pressure jump ΔP = 10 kPa. Average of n = 3 spheroids for t = 0 and t = 5 min and n = 4 for t = 24 h; error bars indicate the standard deviation. (c) Radial cell elongation of HT29 cells shown as a function of distance r. Cell elongation is determined as the ratio of cell distances in radial and circumferential direction; see appendix C. The line is a linear fit that reveals increased cell elongation towards the spheroid centre. From the analysis of data for five different spheroids, we estimate an average slope of this line of (−1.6 ± 0.8) × 10−3 µm−1. The value r2 is the correlation coefficient obtained from the linear fit. (Online version in colour.)