Tecnai g2 20 stwin transmission electron microscope

The particle sizes and zeta potentials of the peptide/siRNA complexes were measured using a Zetasizer 3000HS (Malvern Instruments, Inc., Worcestershire, UK) at a wavelength of 677 nm with a constant angle of 90° at room temperature. Complexes were prepared by mixing 2 μg of si-NC67-M (7.69 μl, 20 μM) and the required amount of peptide (1000 μM) at room temperature. The solutions were then diluted with 0.8 ml of double-distilled water prior to characterization. Moreover, the morphologies and sizes of the complexes were further analyzed by transmission electron microscopy (TEM) (Tecnai G2 20 STWIN transmission electron microscope, Philips, Netherlands) with an acceleration voltage of 200 kV. Briefly, samples were prepared by adding 7 μl of complex solutions onto a carbon-coated copper grid. Then, they were negatively stained with 1% (wt/v) phosphotungstic acid (pH adjusted to 7.3 with 1N NaOH) and air-dried prior to collecting images.

The morphology of OH-MSNs was scanned using a Tecnai G2 20 S-TWIN transmission electron microscope (TEM, Philips, Netherlands). OH-MSNs were stained with 1% uranyl acetate solution and examined for their micellar morphology by a 200 K vacuum accelerated voltage. The zeta potential of OH-MSNs was detected by dynamic light scattering (DLS) at 25°C using a Zetasizer Nano ZS (Malvern, UK).