3.1 Formation, characteristics, and stability of NCs
Formation, characteristics, and stability of NCs were examined using novel RS and RT fusion peptides (Fig. 2A-D). First, NC formation was checked using the electrophoretic mobility shift assay. RS peptides started to retard siRNA bands at a 0.5 N/P ratio and fully retarded them at three and above N/P ratios (left picture of Fig. 2A). On the other hand, RT peptides started to retard siRNA bands at a 1 N/P ratio, however, do not fully retarded until a 70 N/P ratio (right picture of Fig. 2A).
Second, RS-NCs had a hydrodynamic radius of 128.6, 467.0, and 278.5 nm, polydispersity index of 0.17, 0.35, and 0.29, and zeta potential of -23.2, 3.1, and 10.7 mV at the N/P ratios of 1, 3, and 5 (Figs. 2B and S1A). Furthermore, RT-NCs had a hydrodynamic radius of 340.3, 235.7, and 213.4 nm, polydispersity index of 0.43, 0.24, and 0.24, and zeta potential of 5.0, 9.2, and 12.6 mV at the N/P ratios of 5, 20, and 30 (Figs. 2C and S1B).
Third, for stability test using fluorescence particle count, RS-NCs remained over 90% until 24 hours and over 60% until 72 hours in the 10% serum condition (Figs. 2D and S2, Table S3). On the other hand, RT-NCs remained below 40% until 4 hours and completely disappeared at 48 hours. For comparison, R11-NCs, positive control, remained below 10% until 4 hours and completely disappeared at 24 hours.