Finer points of trophectoderm biopsy using the Saturn 5 laser system - Alpesh Doshi
Optimising Trophectoderm Biopsy
using the Saturn 5™ Biopsy Mode
Centre for Reproductive
and Genetic Health.
• Zona drilling Day 3/4/5
• Biopsy day 5/6
• Differentiation of cell lines
– Inner Cell Mass (ICM)
– Trophectoderm (TE)
• TE herniating through the
• ~5 cells excised
– Glass needle
– Larger number of cells can
– Smaller proportion of
embryonic mass taken
– Not taking cells destined to
contribute to the foetus
– Short time for diagnosis
– <50% Blastocyst formation
• Fewer embryos to test
• Increased cycle cancellation
– High levels of mosaicism
• ?Preferential allocation of
abnormal cells to TE?
– Ethical acceptance
Diagram showing the two approaches for blastocyst biopsy
When and what to biopsy?
Take into account how long the diagnosis will take.
Vitryfying blastocysts post biopsy? Or aiming for fresh embryo
Hatching or Hatched blastocysts. Hatching more ideal
If non herniating – trophectoderm cells may have to be ‘sucked’
from zona – ? more risk of lysis and damage to the embryo. Wait.
ICM position – wait to d6 if ICM hatching out.
- Carried out in hepes Buffered media
- Procedure has to be rapid.
- Minimise laser shots by exerting tension on TE in pipette.
- Minimise TE lysis at site of tear.
- Use smaller laser pulses (at CRGH 0.377 m/s pulses with
- Collapse cavity first to prevent shoot up of cells in
• Positioning of
blastocysts, ICM hatching
• Do not take too many cells!
Remember image is 3D
• Control at all times – both
holding, suction and laser.
Utilise foot pedal if
Technique of excising cells
Laser shot and tear cells
Fewer laser shots and ‘brushing’ the cells off
using the holding pipette.
- Difficulty: Cells are sticky!
- more likely to leave cells on
(potential contamination so ensure
pipettes changed if necessary)
- this technique has to be used for
completely hatched blastocysts
TE Biopsy with the new Saturn 5™ Biopsy
• Movable laser.
• Ability to draw the path to apply laser shots.
• Laser shots spaced out to prevent heat build up.
• Facilitates process without the need to free hands for
repeat laser application.
• Prevents application of laser shots at the same point.
• Can bend the path to facilitate laser application in curves ie
Safety of continuous pulses
• Laser Pulses spaced 500
• Heat dissipates within 1
• Power of laser 400 MW
• Movable laser so will not
hit same spot.
Vitrification of biopsied embryos
• >80% pregnancy rates with biopsied/vitrified blastocysts post PGS
(Schoolcraft &Fragouli 2010 )