Volumetric changes in cells during freezing and thawing

Area of Science:

• Thermodynamics
• Cell Biology
• Cryobiology

Background:

• Understanding cell volume changes during cryopreservation is crucial for viability.
• Existing thermodynamic models require refinement to accurately predict thawing dynamics.

Purpose of the Study:

• To develop and experimentally validate a thermodynamic model for the combined freezing and thawing of living cells.
• To investigate discrepancies between model predictions and experimental observations during the thawing phase.

Main Methods:

• A thermodynamic model was developed to predict cell volume changes under thermal protocols.
• Cell volumes were continuously monitored during freezing and thawing using cryomicroscopy.
• Computerized image analysis quantified cell volumes from sequential photomicrographs.

Main Results:

• The model accurately predicted cell volume changes during the freezing process.
• Experimentally measured cell volumes increased significantly faster than predicted during thawing.
• Discrepancies were resolved by incorporating a substantial electrolyte influx into the cell at subfreezing temperatures.

Conclusions:

• The thermodynamic model provides a good framework for understanding cell freezing.
• Accounting for electrolyte influx during thawing is essential for accurate cryopreservation modeling.
• Further research into subfreezing electrolyte transport mechanisms is warranted.