The eggs collected in the OPU process are surrounded by thousands of cumulus cells, defined as COC (Cumulus oocyte complex), which support the development and viability of the egg during its developmental stage and until fertilization. If microinjection (ICSI) is planned, the cumulus cells are separated from the egg by a process defined as denudation in order to identify mature eggs and egg quality.

The eggs aspirated from the follicles (egg sac) are taken together with the surrounding cell cluster. This set of cells allows the eggs to complete their maturity. These cells are not removed from the eggs for approximately 1-2 hours. The egg is expected to complete its final ripening phase. At the end of the waiting period, the cells around the egg are removed from the egg by enzymatic and mechanical methods with the help of hyaluranidase and sterile glass pipettes. Thus, the eggs can be evaluated in terms of maturation (maturity). Approximately 30-60 minutes after the denudation process, microinjection is applied to the eggs that have matured.

In microscopic evaluation, mature and immature eggs are detected and taken to the culture liquids where they will be kept until microinjection process and removed to incubators that provide the necessary environment conditions. Of the collected eggs, only the cells that have completed their maturity (Metaphase 2 – M2) are treated. Therefore, it is not possible to process every collected egg cell.

IVF (in vitro fertilization) (the sperm and the egg into the same culture liquid, the sperm self-fertilization of the egg process) is applied to the eggs denudation process is applied to the eggs 22-24 hours after the mechanical method of collection.