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Materials List
- Day old eggs (at blastoderm stage)
- Sterile
Howard's Ringers solution (see below)
- 70% Ethanol
- Culture dishes (or cheaper alternative) (see below)
- Filter paper rings (1-1.5 cm in diameter)
- Fine forceps
- Scissors
Petri dishes containing albumen agar (see below)
- Inner dish, 2mm of albumen agar covered by 1mm albumen
- 37 °C incubator
- Tapered pipettes, prepare in lab
- Dissecting scope
- Camera

Pre-Laboratory Set-Up

Agar plate preparation:

  • Autoclave 200 ml beaker with stir bar. Wipe eggs with 70% ethanol.
  • Collect 100 ml albumin by separating egg whites from approximately 5 eggs into sterile beaker (discard yolks).
  • Stir at room temperature to break up clumps. Warm to 45°C in water bath.
  • Autoclave 1.3 g agar, 1.3 g glucose and 33 ml Howards' Ringers solution in 100 ml flask for 15 minutes.
  • Cool to 45 °C in water bath.
  • Combine agar and egg whites with stirring. Transfer between flask and beaker to aid combination.
  • Turn water bath up to 48 °C to keep agar from solidifying while pouring plates.
  • Cut tip off of transfer pipet. Transfer approximately 3 ml to 35 mm petri dishes. Avoid transferring bubbles.

    NB: If culture dishes are not available, a cheaper alternative is to use 30mm Petri dish of albumen agar placed in a 60mm Petri dish of Howard’s ringers. Special care must be taken with the alternative dishes to not splash the embryo with ringers once it is placed on the agar as this can cause the embryo to slide off the agar into the moat.


  1. Rinse the egg in EtOH and swirl to release embryo. Lay on its side so that the blastoderm will float to the top.
  2. Fill the moat of the culture dish with Howard’s Ringers solution.
  3. Break the egg and place the yolk into a sterile Petri dish. Alternately, use bent forceps to tap a whole in the shell and remove pieces of the shell until the hole is large enough to put the doughnut onto the blastoderm.
  4. With sterile forceps, use paper donut to frame blastoderm. Allow to sit a while, until it looks drier, this will allow the blastoderm to better adhere to the doughnut.
  5. Lift with tweezers and cut away connective tissue to free embryo.
  6. Place blastoderm, dorsal-side down, onto albumen “island” in culture dish.
  7. Cover, label, and place the dish in the incubator for 30 min.
  8. Set up the microscope and camera.
  9. Remove embryo from incubator and photograph it.
  10. Make a substantial (large) longitudinal cut in the middle of the anterior intestinal portal, through the floor of the foregut with the glass taper cutting from the bottom portion of the hood covering the developing brain. Pass the taper through the incision 2 or 3 times. Record the time of the surgery.
  11. Photograph the embryo, cover it and return it to the incubator.
  12. Observe the embryo daily until the heart forms and starts to beat.
  13. Photograph the embryo daily and record beating if present. Note when heart forms and begins to beat.
  14. If possible, record video of beating heart.

©Cebra-Thomas, 2000

Last Modified: May 2nd 2004

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