PERSPECTIVE: Critical Cooling and Warming Rates as a Function of CPA Concentration

Area of Science:

• Cryobiology
• Materials Science
• Biophysics

Background:

• Cryopreservation relies on cryoprotective agents (CPAs) to prevent ice crystal damage by achieving a vitrified state.
• Successful cryopreservation requires cooling at a critical cooling rate (CCR) and warming at a critical warming rate (CWR) to avoid ice formation.

Purpose of the Study:

• To summarize existing data on CCRs and CWRs for various CPAs.
• To propose a mathematical expression for CCR and CWR to aid cryopreservation protocols.
• To identify critical research gaps concerning CPA cocktails and tissue systems.

Main Methods:

• Literature review of experimental and theoretical studies on CCRs and CWRs.
• Analysis of CPA concentration-dependent correlations for CCRs and CWRs.
• Development of a generalized mathematical expression for CCR and CWR.

Main Results:

• Compilation of CCR and CWR data for diverse CPAs.
• A proposed mathematical model for predicting CCR and CWR.
• Identification of limitations in current understanding, particularly for CPA cocktails.

Conclusions:

• The proposed mathematical expression offers guidance for cryopreservation protocols.
• Further investigation is crucial for CPA cocktails and complex biological systems.
• Understanding CPA behavior in heterogeneous systems is essential for effective cryopreservation.