Fig. 6

Distribution of DRV formulations after intravenous injection into zebrafish larvae. Zebrafish larvae were injected into the posterior cardinal vein at two days post-fertilisation (dpf) with approximately 4 nL of different rhodamine-labelled, fluorescent dehydration-rehydration vesicles (F-DRV). Zebrafish larvae were kept in fresh E3 medium at 28.5 °C and anesthetised in a 0.7 mM tricaine solution before injection and during imaging. Images were acquired at the day of injection, or zero days post-injection (dpi), and at one and two dpi using an Andor Dragonfly 505 confocal microscope fitted with a CFI Plan Apochromat Lambda 10× objective, 561 nm excitation laser, and 600/25 nm band pass filter. Fluorescence images of whole larvae (A-F) are a Z-projection obtained by summation of overlying pixels in the confocal Z-stack. Images also show large sections of the head of one dpi zebrafish larvae, with 3D representations of the blood vessels in the brain (G-J) obtained by pre-processing using a 3D-median filter and rendered using the ImageJ 3D Viewer plugin. All image processing was performed in ImageJ ver. 1.52p. The scale bars represent 500 μm (A-F) and 250 μm (G-J).