When to Use this Technique
The embryo swirl is a very useful technique when attempting to deal with a large amount of zebrafish embryos. It allows the user to collect the embryos into a small, concentrated area in the center of the dish. This is particularly useful when attempting to transfer an amount of embryos into a separate container or dish, or observing a large number of eggs under microscopy.
• Transfer Pipette or Pasteur Pipette
How to Perform the Embryo Swirl
Pre-Swirl: First make sure that there is enough water in the dish that the embryos will not be taken up into the pipette. Typically, this is when the petri dish is a little more than half full.
1) Begin by placing the pipette into an area around the rim of the dish where there are no embryos, or where embryos can easily be moved away from, as seen in Figure 1.
2) Push on the bulb of the pipette, pushing away any embryos near that area.
3) Without sucking in any embryos, release the bulb sucking water into the pipette.
4) In a steady, nonviolent motion, repeat sucking in and expelling water 10-12 times from the pipette creating a vortex in the dish.
5) On the final release of the bulb quickly pull the pipette from the water. The force around the edge of the dish should continue to swirl the embryos until they finally rest in the middle of the dish.
Proper Technique in Action