Mechanical interactions between ice crystals and red blood cells during directional solidification

Area of Science:

• Biophysics
• Cryobiology
• Cell Biology

Background:

• Cellular cryopreservation aims to preserve biological functions during freezing.
• Mechanical interactions between ice crystals and cells are a poorly understood aspect of cryoinjury.
• Red blood cells serve as a model system to study freezing effects.

Purpose of the Study:

• To investigate the mechanical interactions between ice crystals and red blood cells during freezing.
• To determine the role of glycerol and antifreeze proteins in modulating these interactions.
• To assess the impact of mechanical damage on red blood cell survival during cryopreservation.

Main Methods:

• Directional solidification microscopy to observe ice crystal-cell interactions.
• Freezing red blood cells in physiological saline with varying concentrations of glycerol and antifreeze proteins.
• Microscopic observation of cell deformation and destruction during freezing and thawing.

Main Results:

• Ice crystals mechanically interact with red blood cells, causing pushing and deformation.
• Glycerol significantly inhibited these mechanical interactions, improving cell survival.
• Antifreeze proteins, in conjunction with glycerol, exacerbated mechanical interactions, leading to complete cell destruction.
• Cell survival correlated with ice crystal growth habits and the nature of ice-cell mechanical interactions.

Conclusions:

• Mechanical damage is a significant factor contributing to cell death during cryopreservation.
• The efficacy of cryoprotective agents can be influenced by their effect on ice-cell mechanical interactions.
• Understanding and mitigating mechanical injury is crucial for improving cryopreservation protocols for cells and tissues.