Cryopreservation

Egg & embryo freezing Cyprus can expand your family-building options. See how cryopreservation works and what’s involved

Egg Freezing

A woman or couple can preserve their fertility possibilities for the future by storing their eggs. Women who have been given a cancer diagnosis or another condition that may compromise their fertility are eligible for this option. It is also an option for healthy women who want to put off trying to get pregnant until later. A patient will have many of the same procedures that are involved in a standard IVF cycle during an egg-freezing cycle in North Cyprus, including ovulation stimulation, ultrasound monitoring, and egg retrieval. The eggs will be collected, cultivated for a few hours, and then immediately frozen for later use.

Embryo Freezing A woman or couple may decide to freeze any extra embryos after finishing their IVF treatment at Dream IVF. The few who are unsuccessful on their first try or those who want to try again in the future for a sibling benefit from this.

The embryos could be frozen and kept for an illimitable period of time. The medical staff will carry out a Frozen Embryo Transfer after the recipient chooses they want to use their frozen embryos in a cycle (FET). The previous fresh IVF cycle’s stored embryos are recovered here before being transplanted to the prospective mother’s uterus.

Embryo freezing advantages

After a recent IVF cycle, you still have embryos. Embryos can be frozen for upcoming rounds of family formation.

Your fertility may be impacted if you have a sickness or condition like cancer or are undergoing treatment for another illness.

Process of cryopreservation

Using liquid nitrogen (N2) and extremely low temperatures, typically -196 °C/-321 °F, cryopreservation preserves living cells and tissues.

Cryoprotectants are chemicals that keep living cells and tissue intact and stop them from freezing. In order to prevent crystals from harming the cell membrane or other structures, cryoprotectants must be able to minimize the amount of ice that forms. To avoid intracellular crystallization, they must also be able to enter the cells and scavenge water. The “hyper-osmotic” environment created by cryoprotectants makes it easier for cells to become dehydrated. Cryoprotectants with big molecules are employed for this purpose because they cause water to be eliminated by osmosis and diffusion.

Smaller molecules used in cryoprotectants, like ethylene glycol or glycerol, can penetrate cells and stop them from contracting. As a result, cells can maintain their integrity and structure. These characteristics are shared by substances including glycerol, dimethyl sulfoxide, ethanediol, and propanediol.

Cryopreservation can be done in two ways: conventionally and preventatively (vitrification).

Standard Cryopreservation

Conventional cryopreservation, also known as slow programmable freezing (SPF), entails the slow cooling of cells at a rate of 0.3 to 2 degrees per minute down to -196 degrees Celsius (or roughly -320 degrees Fahrenheit), which is the temperature of liquid nitrogen. It also involves the sequential addition of cryoprotectants in series of 10 to 20 minutes. At such temperature, all biological activity inside the cell stops.

The reason for the gradual chilling is to permit the penetration of the cryoprotectants and the gradual dehydration of the cells, preventing the formation of intracellular ice crystals. Because the entire procedure takes a few hours, this method is referred to as “slow freezing.”

Slow cooling prevents intracellular freezing by allowing water to escape from cells when the extracellular fluid gradually freezes (fluid outside the cell). Small molecule cryoprotectants are employed in conjunction with alginates, polyvinyl alcohol, or chitosan to stop the extracellular fluid from crystallizing and recrystallizing.

The pace of freezing varies with cell size and permeability, but for many mammalian cells, a normal chilling rate of roughly 1 °C/minute is thought to be suitable. For cryoprotectants like glycerol or dimethyl sulfoxide, a rate-controlled freezer or a tabletop portable freezing container can be utilized to reach the 1 °C/minute pace.

Vitrification

An developing technology that varies from conventional cryopreservation is vitrification, commonly referred to as prevented cryopreservation.

Cells are “flash frozen” to -196°C using the “vitrification” technique, which causes the cells to turn “glass-like” or “vitrified.” Vitrification is faster than gradual freezing, which might take hours to complete.

For cryopreservation to be successful, cooling rate is crucial. 10,000 times faster is the freezing speed, measured in megakelvins per second. Ice crystals in the cell are less likely to form the faster the cooling process is.

To avoid the toxicity of cryoprotectants at ambient temperature and to accomplish vitrification, rapid cooling is required. Cells solidify during the process by becoming more viscous and preventing dehydration.

A higher viscosity and a lower freezing temperature take the role of the classic cryopreservation method’s crystallization-based shift from liquid to solid. Many compounds exhibit both of these properties, but larger molecules typically perform better, particularly in terms of viscosity. The mixture solidifies into an amorphous ice that resembles a solid liquid.

The high concentration of cryoprotectants is the only issue with vitrification.

Lilia Kuleshova was the first scientist to disclose the vitrification of tissue and the first to successfully vitrify a woman’s eggs (oocytes), which led to a live delivery in 1999.

Thawing of embryos

It is a cryopreservation method done in reverse. Rehydrating the cell is one of the most important aspects of a good thaw. Sperm or embryos warm up in a water bath or in the air at a warming rate that is significantly higher than the pace at which they cool. They are warmed to body temperature after initially reaching room temperature. The cryoprotectants are gradually diluted out in embryos through a number of processes. Within two to four hours of reaching body temperature, they are often inserted.