Fig. 1

Circulation of NPs in the zebrafish embryo, manual analysis. A) Acquisition of the zebrafish embryo at 48 h post fertilization in the transmission channel; the rectangular inset shows the area where the caudal region images were taken. B–E) Images of the caudal vein of zebrafish injected with fluorescent NPs (here 100 nm liposomes with PEG) imaged at different time points—B) 5 min, C)1 h, D) 4 h, and E) 24 h. B) The main blood components of the caudal region are shown by arrowheads (caudal artery and caudal vein). C) The rectangles used for quantification of fluorescence are shown (arrowheads); these are either manually or automatically placed on the caudal artery and in between intersegmental vessels. D,E) The decrease in fluorescence of the caudal artery (arrowheads) can be seen at 4 and 24 h. B–E, insets) The values for fluorescence in the artery are normalized relative to the overall NP fluorescence in the whole fish. Scale bars: A) 500 nm and B–E) 200 nm.