4.5. Zeta Potential

The zeta potentials of the complexes were measured using a Malvern Instruments Zetasizer Nano-ZS (Malvern Instruments Ltd., Malvern, UK). Measurement was carried out at 25 °C. From 10 to 15 measurements were collected for each sample and averaged. Increasing concentrations of the dendrimer in the range of 0.5–20 µM were added to siRNA at 0.5 µM and the zeta potential was measured. The zeta potential value was calculated directly from the Helmholtz–Smoluchowski equation using Malvern software [43].