Dual Thermal Block Cryopreservation Apparatus
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Solution Overview
Problem
Current cryopreservation methods face limitations in achieving efficient cooling and warming rates for tissues, leading to suboptimal recovery and toxicity issues due to the use of chemical protectants, and existing cooling block designs are inadequate for whole tissue cryopreservation, especially for thicker tissues.
Innovation Solution
An apparatus and method utilizing two thermally conductive blocks with sealing members to create a fluid-tight chamber around the tissue, allowing simultaneous cooling and warming from both sides, and applying pressure to enhance heat transfer, thereby achieving higher cooling and warming rates while minimizing the need for high concentrations of cryoprotective agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional cryopreservation methods are used with secondary containers, then cooling and warming rates are limited by heat transfer through multiple layers, but this approach provides contained sample handling
Solution Approach 1:
The invention removes the secondary container (tube) from the cryopreservation system, exposing the tissue sample directly to the cooling medium. This extraction eliminates the thermal resistance of tube walls and multiple media layers, enabling direct heat transfer between the tissue and cooling/warming medium, thereby achieving ultra-rapid cooling and warming rates
Solution Approach 2:
The invention introduces a specialized cold block apparatus with a chamber that directly contacts the tissue sample. This cold block serves as an intermediary thermal conductor that provides controlled, rapid heat transfer without the thermal resistance of secondary containers. The cold block design includes features like recesses and direct-contact surfaces to maximize thermal coupling between the cooling medium and tissue
2Speed
If tissues are plunged directly into liquid nitrogen, then cooling rates improve, but the Leidenfrost effect creates vapor insulation that reduces cooling kinetics
Solution Approach 1:
The cold block apparatus acts as an intermediary between liquid nitrogen and the tissue sample. The cold block is first cooled to liquid nitrogen temperature, then brought into contact with the tissue. This intermediary approach transfers heat efficiently without causing the Leidenfrost effect, as the cold block surface temperature is controlled and the contact is managed, eliminating vapor insulation issues
Solution Approach 2:
The cold block is pre-cooled to the desired temperature before contact with the tissue sample. This preliminary cooling action ensures that when the tissue is placed in the chamber, immediate and controlled heat transfer occurs without the tissue warming the block enough to cause vaporization and Leidenfrost effect
3Reliability
If high concentrations of cryoprotective agents are used to prevent ice formation, then ice-avoidance is achieved, but toxicity to cells and tissues increases
Solution Approach 1:
The invention changes the key parameter from chemical protection (high CPA concentrations) to physical protection (ultra-rapid cooling rates). By achieving cooling rates sufficient to prevent ice crystal formation through physical means, the system eliminates or reduces the need for high concentrations of toxic cryoprotective agents, thereby maintaining ice-free cryopreservation while reducing chemical toxicity
4Reliability
If cold block designs are used for cryo-electron microscopy, then ice-free cryopreservation is achieved at depth of 200-500 micrometers, but this is insufficient for thicker tissues
Solution Approach 1:
The invention enhances the cold block design by introducing two-sided cooling capability. The tissue sample is positioned between two cold blocks that cool simultaneously from opposite directions. This dimensional approach (cooling from both sides rather than one side) effectively doubles the penetration depth capability, enabling ice-free cryopreservation of much thicker tissues while maintaining the reliability of ice-free conditions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient cryopreservation of thicker tissues by maximizing heat transfer coefficients, reducing ice formation, and minimizing tissue damage, allowing for improved recovery and reduced toxicity, with simulated cooling and warming rates of up to 105° C/min and 104° C/min respectively.
Implementation Method 1
two thermally conductive blocks with sealing members to create a fluid-tight chamber around the tissue, allowing simultaneous cooling and warming from both sides
Implementation Method 2
applying pressure to enhance heat transfer, thereby achieving higher cooling and warming rates
Data Source
AI summary
A method and apparatus for the processing of tissue and cellular material during cryopreservation and/or processing for microscopy. The method and apparatus maximizes heat transfer coefficients by using liquid-free cryopreservation protocols and maximizing glass transition characteristics through increasing pressure during cryopreservation. Cooling rates combined with megapascal pressures reduced the required concentration of cryoprotective agents (CPAs) needed for ice-free cell and tissue cryopreservation.