Fig. 2. Transfection efficiency in MCF-7 cells comparing the effect of perfluoroalkyl modification of polymers on both small and large plasmids. (a and b) Fluorination of dendronised polymers increased EGFP-encoding pDNA transfection efficiency significantly in all cases ((a) p ≤ 0.0001; (b) p ≤ 0.001) and fluorinated dendronised polymers 11c and 12c achieved transfection efficiencies similar to Lipofectamine 2000 (p > 0.05). In (a), G4 and G5 PAMAM dendrons (9c, 10c, 11c and 12c) are compared, and in (b), G5 PAMAM dendronised polymers (10a–d and 12a–d) are compared. (c) Representative fluorescence microscopy images of transfection efficiencies in MCF-7 cells with fluorinated dendronised polymers 11c and 12c at N/P = 2.5 and 5 compared to Lipofectamine 2000. (d) MCF-7 cells were transfected with a large EGFP-expressing plasmid (10.3 kb); transfection efficiency was quantified with flow cytometry. Polymer 12c achieved a significantly higher transfection efficiency than Lipofectamine 2000 (p ≤ 0.0001). (e) Delivery of large EGFP plasmid to MCF-7 cells using fluorinated dendronised polymer 12c compared to Lipofectamine 2000. (f) Reaction scheme for fluorination of terminal PAMAM primary amines using heptafluorobutyric anhydride. Dendronised polymers 9a–10d were all treated to give fluorinated dendronised polymers 11a–12d using the same method.