PICSI is the newer modification of the above-described method of ICSI. It is currently the most statistically efficient way to achieve in vitro conception. PICSI was created to carry out sperm selection on extra molecular level, which is invisible otherwise.
The process requires the usage of hydrogel called Hyaluronan (or hyaluronic acid, or Hyaluronate, or HA). In PICSI procedure, it is planted onto the bottom of a lab dish. Hyaluronan is an essence present in every human body, and among other allocations, it serves as a component for the shell membrane surrounding female egg. Biochemically mature spermatozoids (that is having the complete set of receptors essential for consumption) bind with Hyaluronan, and the details of this interaction are the basis for the embryologist to make judgment as per how perspective this particular sperm cell is for further implantation via ICSI. The spermatozoa, which have successfully passed this test, with then be morphologically analyzed and selected through ICSI-MAQS technique.
It has been observed by scientists that in natural course of things, only the viable and perspective spermatozoids will bind with Hyaluronan, and one of those will later enter into the female egg. This explains the sperm selection principle of PICSI, based on the behavior of sperm cells, when conditions most similar to natural are applied.
PICSI technique was first introduced by Doctor Gabor Huszar, Senior Research Scientist in Obstetrics and Reproductive Sciences at Yale University School of Medicine. As part of his research and clinical application of the new method, Doctor Huszar has again demonstrated that, as it happens in natural course, during PICSI analysis, only the mature spermatozoids and only those with least DNA and chromosome pathology will bind with Hyaluronan. The results of his tests also show that this criteria proves to be more selective than that based purely on commonly applied morphological features selection. The results of clinical adoption of PICSI methods from reproductive medical centers worldwide demonstrate that HA-selected spermatozoa show “higher fertilization rates, better embryo quality, improved implantation rates, higher pregnancy rates and substantially lower first trimester miscarriage rates” after IVF programs (quoted from Dr. Huszar’s report at LONDON Alpha Meeting 2012).