During intracytoplasmic sperm injection (ICSI), the biologist has usually much more sperm available than eggs, which is why he or she has to select the sperm cells in some way. Traditionally, the selection happens on optical grounds under the microscope, that is whether the sperm cell is of normal shape and moves well. In research, there are several approaches to improve this mode of selection, knowing that one part of errors at fertilisation comes from the sperm side. However, the majority of errors still can be attributed to the egg side, especially in women over 35 years.
Ideally, one would recognize eggs and sperm cells with normal genetic code in the first place; this is not possible, since examining the genetic code would destroy the cells. Optical observation, even at highest magnification (so-called IMSI or MSOME method), does by no means correlate perfectly with the genetic code; optical beauty therefore does not guarantee for normal content. Our biological team opted for a different approach and introduced the so-called physiological sperm selection in the summer of 2010.
Picture on the right: The biologist uses special dishes with red patches coated with hyaluronic acid. Mature sperm cells stick with their heads to hyaluronic acid, while the tail moves vigorously.
In this method, the washed sperm cells are put into contact with hyaluronic acid, a biological polymer which is also found in the gel-like outer layers of the human egg. Mature sperm cells do have docking sites (receptors) on their heads and stick to hyaluronic acid, while the tail moves vigorously, much alike natural fertilisation. According to research work performed at Yale University, the sperm cells selected with this method are more mature, have less defects in the genetic code substance DNA and possess more often the correct number of chromosomes, i.e. are genetically superior.
We recommend functional (physiological) selection in the following situations:
The special selection method represents an additional effort by the biologist as well as additional material, which is why we have to charge a moderate surcharge. We would be happy to give you additional information personally.