Spheroid size.

Size measurements of human normal dermal fibroblast (A), colon cancer (B), bladder cancer (C), and metastatic breast cancer (D) spheroids. Left panel: representative fluorescence microscopy images of a spheroid just after electroporation (8 pulses of 100 μs, 1000 V/cm, and 1 Hz) in buffer containing propidium iodide (PI) to visualize electropermeabilized cells and light microscopy images of another spheroid just before treatment (LM). Right panel: Growth curves of the spheroids after treatment with respectively 168 mM calcium (Ca), 1 mM bleomycin (Bleo), electroporation (EP), 168 mM calcium electroporation (Ca EP), electrochemotherapy using 1 mM bleomycin (Bleo EP), and untreated controls (Control). Measurements performed before treatment and at day 2, 3, and 4. Spheroid size is normalized to the size before treatment, means +/- SD, n = 5–6.