Fig. 2

Effective nanoparticle-assisted delivery of siRNA into the adult zebrafish heart. (A) Fluorescence images of CY5-siRNA accumulation in isolated zebrafish heart under the in vivo imaging system. Note that fluorescence signals were hardly detectable in the negative control (Mock) and unencapsulated siRNA (Naked) groups at 24 hpi, and were increased in the nanoparticle-encapsulated siRNA groups from 3 to 24 hpi. An arbitrary scale of fluorescence signal is shown from blue (low) to red (high). (B) Quantification of CY5-siRNA in heart tissues using the in vivo imaging system (*P<0.05). (C–G) Fluorescent images of cryosections of heart tissues under confocal microscopy. Note the clear CY5-siRNA signal in the experimental group at 3, 6 and 24 hpi but very little signal in the negative control (Mock) and naked siRNAs (Naked) groups at 24 hpi. Enlarged siRNA localization is shown (E–G, low-right corner). DAPI was used to stain nuclei. Scale bar, 50 µm. (H) Quantification of the CY5-siRNA fluorescence signals in Fig. 2C–G. (*P<0.05).