**3.6 Electroporation experiments**

Cells were cultivated to 80 % confluency as described above. Every 100 mm plate was trypsinated with 1 mL Trypsin/EDTA for 30 s (HAEC), and 90 s (HASMC) to detach the cells. Trypsinization was stopped by adding 3 ml culture medium with serum. After washing twice with ice-cold PBS, cells were redispersed in ice-cold electroporation buffer (100 mM Hepes, 137 mM NaCl, 4 mM Na2HPO4, 6 mM Dextrose) at a concentration of 107 cells/ ml. Electroporation experiments were carried out using a Gene Pulser II (BioRad Laboratories, Muenchen, Germany). 500 µL of cell suspension was poured in a chilled 0,4 cm gap cuvette. After adding 20 µg DNA (1 mg/mL TE-buffer pH 7,0; Tris 10 mM, EDTA 1 mM) the cuvette was placed on ice and electroporated with the following settings: for HAEC: 350 V, 750 µF; for HASMC: 500 V, 950 µF. After the shock, the cuvette stayed on ice for 10 min. Then, cells were transferred into a 100 mm culture plate, (gelatine-coated plates for HAEC, see section "cell culture") and incubated for 48 h at 37 °C and 5 % CO2. Fluorescent pictures were taken with an Axiovert S 20 (Zeiss, Jena Germany, 20x).

As a positive control experiment, C3-Toxin plasmid was electroporated into the cells to see if DNA was delivered into the nucleus. Effective delivery was achieved when cells were rounded up and dead.

As cells were not vital enough for FACS analysis, fluorescent and non-fluorescent cells were counted via "Neubauer Zählkammer". Counting was repeated twice for every culture plate for at least 3 independent experiments.
