Matey Andonov Chief Scientist, London Women’s Clinic
Intracytoplasmic sperm injection (ICSI) is an in vitro fertilisation (IVF) procedure in which a single sperm is injected directly into an egg. This procedure is most commonly used to overcome male infertility.
A small amount of washed and prepared sperm is placed into thick viscous media containing poly vinyl pyrrolidone (PVP) in a dish. The PVP slows the sperm down so that they can be selected according to their shape, motility and trajectory.
The most normal looking sperm are selected and then immobilized by squashing their tails with a glass injection needle. The sperm are sucked into the needle tail-first ready to be injected.
A holding pipette secures the mature oocyte and then a thin, sharp glass micropipette, loaded with a single sperm, pushes first through the zona pellucida and then the oolemma.
Extra suction from the syringe attached to the injection micropipette is normally needed to fully break through the elastic oolemma membrane to ensure the sperm is fully inside the cytoplasm.
After the ICSI procedure, the oocyte is placed into the incubator and checked the following day for signs of fertilisation.