ICSI (injection of a single spermatozoon into the cytoplasm of the egg cell) — selection of the spermatozoon with the best morphology and motility for subsequent insemination of the egg cell via micro-manipulation. Until now, the only technique for the selection of the best spermatozoon for egg cell insemination has been visual observation. Embryologists often see immature spermatozoons. Spermatozoons of good morphology and motility may have other defects which cannot be assessed visually, such as DNA fragmentation or impaired development. Such defects affect the quality and development of embryos as well as may contribute to termination of pregnancy.
Using the new PICSI technique (injection of a single, physiologically the best spermatozoon into the cytoplasm of the egg cell) makes it possible to select spermatozoons without any visually detectable defects as well. This technique improves the selection of spermatozoons up to 98%. In this technique, spermatozoons are placed in hyaluronic acid, which binds mature spermatozoons. As we know, only fully mature spermatozoons, which have reached the final stage of spermatogenesis, have developed hyaluronic acid binding receptors. Immature spermatozoons, in their turn, have increased DNS fragmentation, aneuploidy (abnormal number of chromosomes) and immature cytoplasm, and all this impairs their fertilisation capacity. The use of the new PICSI technique improves the chances of achieving a successful pregnancy.