Fig. 2
Characterisation of the Au@PP/RA/siRNA nanosystem. a Representative TEM images of AuNP-based nanosystems. Scale bars, 100 nm. Insets, enlarged micrographs. Scale bars, 10 nm. b UV–vis absorbance spectra of the indicated nanosystems and ATRA. Insets, photographs of the indicated nanosystem samples. c Size distribution of the nanosystems measured by dynamic light scattering (DLS). d Zeta potential of the nanosystems in 10 mM HEPES buffer (pH 7.4). The data are shown as the mean ± s.d. (n = 3). e Agarose gel electrophoresis retardation assay of siRNA at various w/w ratios of Au to siRNA. Complete retardation of siRNA was achieved at the w/w ratio of 7.5 for both nanosystems. f siRNA protection assay of different nanosystems treated with RNase A for 2 h at pH 7.4 or 6.5. Compared to the untreated lane 4 (Au@PP/siRNA without RNase A treatment, set as 100%), the remaining siRNA amounts were 81%, 77%, 84%, 77 and 60% for lanes 5–9, respectively, after RNase A treatment
