Biocompatibility assay and fluorescence imaging of CDs in zebrafish

Different concentration of CDs were confected using deionized (DI) water as solvent. Then 50 embryos at 4 hpf were placed into each well of six-well plates with 8 ml different concentration of CDs (as descripted in Fig. S9), and DI water was used as control without CDs. After the embryos were exposed to different concentrations of CDs for a certain time, the CDs were replaced with DI water and zebrafish embryos were raised until the stated time. Three replicate trials were conducted for each group. Microscopic images were taken by the Nikon SMZ18 NIS-Elements BR Stereo Fluorescence Microscope under different excitation spectra, after washing the embryos for 6 times.

The 10-day-old zebrafish were investigated by the same method above, the zebrafish embryos were normally cultured for 10 days. Then 20 healthy zebrafish larvae were selected and exposed to different CDs for 2 days. The effect of CDs on larvae was traced by taking microscopic images. Three replicate trials were conducted for each group.