Figure 1

(a) Cryosection of a spheroid performed directly after labeling with RITC core-shell nanoparticles (RITC-CS). The internal autofluorescence is due to the necrotic core. The inset shows an individual cell with CS clusters. (b) Fluorescence intensity of FITC-CS- and RITC-CS-labeled cells coming from 40 dissociated spheroids, measured by flow cytometry. The color code indicates the density of events. The upper right quadrant corresponds to a cell having both a high number of RITC-CS and FITC-CS, corresponding to less than 2% of the events. 40000 events recorded.Reuse & Permissions

Figure 2

(a)–(d), (top): Superposition of cryosections of spheroids just after the staining (red) and four days later (green). The dashed line shows the radius at day 4. The autofluorescent core has been hidden for convenience. Bottom: Time evolution of the normalized distribution of RITC-CS-labeled spheroids from day 0 to day 4: red, day 0; purple, day 1; dark blue, day 2; light blue, day 3; green, day 4. (a) and (b): Spheroids at steady state, with no mechanical stress and a steady-state radius of $450\mu \mathrm{m}$ (a) or under 5000 Pa and a steady-state radius of $300\mu \mathrm{m}$ (b). (c) and (d) Growing spheroids, with an initial size of $200\mu \mathrm{m}$, in the absence of mechanical stress (c) or under 5000 Pa (d). The dots indicate the border of the spheroid. Each distribution is the distribution for one spheroid, and each experiment has been repeated $N\ge 3$ times.Reuse & Permissions

Figure 3

Model. (a) Growth rate as a function of position inside the spheroid. (b) Calculated velocity field with the parameters extracted in Table . Blue, 0 Pa; dashed-red, 5000 Pa; dashed-purple arrow, convergent flow; green arrow, divergent flow.Reuse & Permissions

Figure 4

Amplitude [(a), (b)] and position [(c), (d)] of the maximum of the CS distribution for steady state [(a), (c)] and growing [(b), (d)]. Solid lines in (a)–(c) are the fitting curves. In (d), solid line is the numerically integrated model, with no adjustable parameter. The error bars correspond to the uncertainty in the evaluation of the position and the amplitude of the maximum for each experiment.Reuse & Permissions