Figure 4.

Effect of pulse length and voltage on intracellular calcein uptake after electroporation with a microneedle electrode device. (a) Representative confocal microscopic images of human prostate cancer cells after the delivery of calcein by electroporation using a 2 ms square wave pulse. Each picture contains 4 sections, and each section represents an image taken by a different channel (top left: brightfield, top right: green fluorescence, bottom left: red fluorescence, bottom right: combination of all channels). Additional images can be seen in Supplemental Figure S2. (i) Unpulsed control, (ii) 57 V (scale bar = 50 µm) and (b) Uptake efficiency of calcein using different pulse length and voltages: (☒) 0.5 ms, (■) 1 ms, and (■) 2 ms. (c) Cell viability at each pulse condition. Data represent the average of n=3 replicate experiments. Standard deviation bars are shown. ^× not significantly different (Student’s t-test, p > 0.05)