FIGURE 4.
Effect of field strength, pulse length, and number of pulses on electroporation-mediated uptake as a function of radial position of cells within multicellular spheroids. Conditions used were (A) one 22-ms pulse with field strengths of 0.2 (▪), 0.4 (○), and 0.5 (♦) kV/cm; (B) one 0.5-kV/cm pulse with pulse lengths of 1 (Δ), 7 (▪), 20 (○), and 40 (♦) ms; and (C) one (▪), two (○), and four (♦) 20-ms, 0.5-kV/cm pulses. The points represent experimental data from spheroids. The lines represent predictions from the model developed in this study to account for changes in cell state (Eq. 1), local solute concentration (Eqs. 2–6), and local electric field (Eqs. 7–9) within spheroids (see text). Average is mean ± SE; n ≥ 3.