Vitrifying multiple embryos in different arrangements does not alter the cooling rate.

Area of Science:

• Reproductive Biology
• Biomedical Engineering
• Cryobiology

Background:

• Vitrification is the preferred method for gamete cryopreservation in fertility clinics, offering superior survival rates over slow freezing.
• The Open Cryotop® device is widely used, but the impact of varying sample numbers and arrangements on cooling efficiency is not fully understood.

Purpose of the Study:

• To develop and computationally solve a mathematical model simulating the cooling of oocytes and embryos.
• To investigate how the number and spatial arrangement of samples on the Open Cryotop® device influence cooling rates and subsequent survival rates.

Main Methods:

• A mathematical model was created to simulate heat transfer during vitrification.
• Computational methods were employed to analyze temperature changes over time for various sample configurations.
• The effect of spatial arrangement and sample number on cooling rates was quantified.

Main Results:

• Neither the spatial arrangement nor the number of samples significantly impacted cooling rates when cryoprotectant volume was minimal.
• Cooling times were consistently rapid, typically less than half a second, irrespective of sample configuration.
• The study confirmed that rapid cooling is achievable across different sample loads.

Conclusions:

• The number and arrangement of oocytes or embryos on the Open Cryotop® device do not critically affect cooling rates.
• Adherence to manufacturer guidelines for minimal cryoprotectant volume ensures rapid cooling and optimal vitrification outcomes.
• This validates the flexibility of the Open Cryotop® for various sample loads in fertility preservation.