Fig. 6. Phase contrast images of CHO cells after (a) no addition of lipid (b) addition of 500 μg mL^–1 POPC (c) addition of 500 μg mL^–1 5 (d) addition of 50 μg mL^–1 Lipofectamine 2000. After 24 h of incubation, cells in a, b and c were alive and adherent to the surface. Cells in d were dead as they were no longer adherent to the surface.