Cryopreservation CSIR NET life sciences

Summary

This tutorial video delves into cryopreservation, the process of preserving biological tissues at extremely low temperatures, typically -195°C, using liquid nitrogen. It highlights the importance of this method for halting cellular activity to prevent cell death, and discusses the challenges of avoiding ice crystal formation which can damage cells. The concept of vitrification is introduced as a gradual temperature increase process using vitrifying agents to safely thaw preserved tissues without cell rupture, ensuring successful tissue preservation.

Takeaways

• 🧊 Cryopreservation is the process of preserving biological specimens at very low temperatures, typically around -195°C, which is the boiling point of liquid nitrogen.
• 🌡 The extreme cold is necessary to halt all cellular processes, preventing any enzymatic activity that could lead to cell death.
• 🧬 Biological tissues, including tissues and organs, are preserved to maintain their viability for future use, ensuring that they remain 'alive' during storage.
• ❄️ Liquid nitrogen is commonly used in cryopreservation due to its extremely low temperature, which is crucial for stopping all biological activity within the tissues.
• 🔬 If tissues are stored at higher temperatures, cellular activities such as enzyme functions and metabolic processes would continue, leading to cell death and failing the purpose of preservation.
• 💧 The risk of ice crystal formation during cryopreservation can damage cells; rapid freezing helps to mitigate this by preventing water from expanding and rupturing cell membranes.
• 🔬 Vitrification is a process used to slowly transition tissues from cryopreservation temperatures to normal temperatures, using agents that prevent the formation of damaging ice crystals.
• 🌡 The vitrification process involves a gradual increase in temperature, avoiding rapid changes that could cause cell membrane rupture and cell death.
• 🛠 Vitrifying agents are used to facilitate the controlled warming of tissues, ensuring stability and preventing damage during the thawing process.
• ♻️ The script emphasizes the importance of carefully managing temperature changes during both the freezing and thawing processes to maintain the integrity of biological samples.
• 📚 The tutorial aims to provide a basic understanding of cryopreservation, highlighting the significance of temperature control and the role of vitrification in preserving biological tissues.

Q & A

What is cryopreservation?

Cryopreservation is the process of preserving biological specimens or samples, such as tissues, organs, or cell lines, at extremely low temperatures, typically around -195°C, to maintain their viability for future use.

Why is liquid nitrogen commonly used in cryopreservation?

Liquid nitrogen is used because its boiling point is -195.8°C, which provides the ultra-low temperatures necessary to halt all cellular processes and prevent cell death, making it ideal for preserving the viability of biological tissues.

What is the significance of storing biological tissues at -195°C?

Storing at -195°C halts all cellular processes, including those that could lead to cell death such as apoptosis. This temperature is crucial to prevent the activation of enzymes that could degrade the tissue or lead to cell death.

What is the risk associated with rapid freezing of biological samples?

Rapid freezing can lead to the formation of ice crystals within the tissue. The expansion of water as it freezes can cause cell membranes to rupture, leading to cell death, which is why a controlled freezing process is essential.

What is vitrification in the context of cryopreservation?

Vitrification is the process of slowly warming a cryopreserved tissue from ultra-low temperatures to normal temperatures using vitrifying agents. This gradual increase in temperature helps prevent damage to the tissue caused by rapid temperature changes.

What role do vitrifying agents play in the warming process of cryopreserved tissues?

Vitrifying agents are used to prevent the formation of ice crystals during the warming process. They help to stabilize the tissue and allow for a controlled, gradual increase in temperature, reducing the risk of cell damage or death.

Why is it important to avoid rapid temperature changes when thawing cryopreserved tissues?

Rapid temperature changes can cause significant stress to the cells, potentially leading to cell membrane rupture and cell death. A controlled, gradual increase in temperature helps to minimize these risks.

What happens to cellular activities at temperatures above -195°C?

At temperatures above -195°C, cellular activities such as enzyme functions and metabolic processes can begin to occur, which could lead to cell death if the cells are not intended to be active.

How does the process of vitrification help maintain cell stability during thawing?

Vitrification involves a step-by-step increment of temperature, which allows the cells to gradually adjust to the change, thereby maintaining cell stability and reducing the risk of damage.

What is the typical temperature range for the vitrification process?

The vitrification process involves gradually increasing the temperature from -195°C, possibly through stages such as -50°C, -25°C, 0°C, and finally to 35°C, depending on the specific requirements of the tissue being thawed.

Why is the preservation of living tissues important in cryopreservation?

The preservation of living tissues is important to ensure that the biological specimens remain viable for future use, such as in transplantation or research, without the risk of cell death or degradation.