Figure 3. Adherent and aggregated cell respiration down-modulation upon contact.

(A) Microscope images of CTC labelled cells in suspension and adhering to the 25 µm diameter particle surface. (B) FCM dot plots: SSC (left panels), FL1 (middle panels) and respiration index f _R (right panels) versus FSC showing cells (upper row, a to c) — single free-floating cells appear as light gray dots, aggregates as dark dots — and cells adhering to particles (lower row, d to f)); FL1 dot plots (middle panels) reporting GFP expression show cell counting gates, from R₂ to R₁₂ for aggregates and from R₁₀ to R₁₃₅ for particles. Gates were defined as explained in the text based on sample single cell mean FL₁ value. (C) Graphs of normalized respiration index as a function of (a) number of cells (♦) or 2.8 µm diameter beads (•) per aggregate and (b) number of cells per particle. (D) FL1 versus FSC dot plot of 2.8 µm beads used as aggregation controls and population counting gates.