Intravital imaging in zebrafish using quantum dots.

Background/aims: Fluorescent quantum dots (QDs) are powerful multipurpose interfaces of nanotechnology providing long-term and multicolor imaging of cellular and molecular interactions. The application of QDs in living organisms is just beginning to be explored, and zebrafish embryos may be suitable vertebrate model organisms for intravital imaging with QDs. To investigate their potential in skin research, we used QDs as microangiography contrast agents and attempted to visualize the cardiovascular system in zebrafish. We also attempted to find the pathway relationship between the cardiovascular system and the nerve network using QDs together with the transgenic zebrafish line.

Method: Quantum Dot QD605, which reveals green color under the fluorescent microscope, was used as a microangiography contrast agent. The olig2-Dsred transgenic zebrafish line, which expresses motor neurons in red color, was used together with QDs. Images of QD605-injected embryos were recorded with a digital camera.

Results: Combining the green fluorescence of QD605 and the red fluorescence of olig2-Dsred transgenic zebrafish, we could obtain detailed images manifesting the spatial relationship between the vascular and the nervous system of zebrafish

Conclusion: QDs could easily be used as a bright microangiography agent in living embryos. Our image of the vascular and motor nervous system in zebrafish showed a similar pattern of trajectory overall. However, their segmented repetitive networks along the dorsoventral axis were not completely overlapped.