Electroporation affects the transfer of fluorescein through inner membranes, but not the chorion. Embryos were incubated with 10 μg/ml fluorescein for 40 minutes (A, blue bars; B-D); subsequent electroporation (A, red bars; E-G) was performed using 35 kHz, 15 V, 5000 ms, 1 pulse. Pictures were taken after 30 minutes washing time. Embryos are shown in lateral (B,E) and dorsal (D,G) view with anterior to the top. Scale bar 250 μM. Abbreviations: ELPO, electroporation; DIFF, diffusion.