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. 2007 Dec 7;94(6):2142–2149. doi: 10.1529/biophysj.107.113472

FIGURE 4.

FIGURE 4

Confirmation of the GAG clustering caused by CPCs. DLS intensity autocorrelation functions were recorded at eight different angles (30–150°). Displayed are recordings at θ = 90° for 50% of heparin's (13.7 μM, 1.4 ml) sulfate charges saturated with indicated cationic compounds. Recordings for AOR (ethidium bromide and propidium iodide) and DOTAP are displayed for 10% and 5% charge saturation of heparin, respectively, so that the particle size did not exceed the sensitive range of the instrument (<1 μm). All CPCs caused a clustering of GAGs as evident from the complex size of >70 nm (Table 1), which is considerably larger than a single GAG molecule saturated with the defined number of CPCs. In contrast, virtually no light scattering was found for the structurally related but non-cell-permeant compounds 10, 9, and 6 even when a 16-times higher receiver gain was used than for the other compounds. Individual tracings are (10) ethidium bromide, (9) l-arginine, (6) propidium iodide, (2) PLL16, (7) HIV Tat-PTD, (1) nona-l-arginine, (3) polyethylenimine, (8) penetratin, (5) acridine orange, and (4) DOTAP vesicles ([DOTAP]out = 4.8 mM, 30 nm, DOTAP:DOPC = 3:7 (n/n)). Temperature was 20°C. Buffer in all experiments is 30 mM phosphate and 77 mM NaCl at pH 7.40 (ionic strength of 154 mM).