1. VITRIFICATION:OPEN SYSTEM- PRACTICES, PROS & CONS
ADESUWA OGBEBOR-EVANS

2. Methods of Cryopreservation
Slow-Freezing
Vitrification
Typically different methods but are meant to achieve the same desired results. They aim to remove fluid from cells resulting in dehydration and store them in extremely cool temperatures (Liquid Nitrogen) without the formation of intracellular ice.
The practical advantages of vitrification has made it more attractive to ART laboratories worldwide.

3. Vitrification
Vitrification is an ultra rapid freezing method used for the cryopreservation of human oocytes and embryos. Currently the most practiced method of cryopreservation in most laboratories in Nigeria and all over the world
Vitrification protocols include
Open- System
Semi- Closed System
Closed- System
Currently, there’s no consensus on which of the protocol is optimal

4. OPEN-SYSTEM - PRACTICES
The differences between the various vitrification protocols is classified based on the contact between the medium containing the embryo or oocyte and liquid nitrogen.
In the full open system of vitrification, after dehydration of cells and loading onto the device, the straws are plunged directly into liquid and kept for storage in liquid nitrogen e.g OPS
In the open cooling-closed system, the cells are plunged into liquid nitrogen after dehydration and kept in sealed or closed straws for storage

5. OPEN SYSTEM – PROS & CONS
Simple and Fast – Goes through 2 diluents and time frame is usually with mins
Doesn’t require any fancy equipment
CONS
Risk of contamination due to contact with liquid nitrogen. However, there’s no documented case of disease transmission
Do we consider the facts or theories?