Ice-Free Cryopreservation of Tissue Matrices
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Solution Overview
Problem
Conventional cryopreservation methods for biological tissues, such as allograft heart valves, face limitations due to ice formation during freezing, leading to structural deterioration, immune responses, and high preservation and storage costs, with existing methods failing to consistently preserve extracellular matrix integrity and long-term function.
Innovation Solution
A method involving immersion in a high concentration cryoprotectant solution (at least 75% by weight) and cooling to a temperature between -20°C and the glass transition temperature of the solution without ice formation, allowing for ice-free cryopreservation and maintaining extracellular matrix integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional freezing cryopreservation is used, then storage and preservation are enabled, but ice crystals form that mechanically disrupt tissue structure and damage function
Solution Approach 1:
The patent changes the fundamental parameter of the preservation state from crystalline (frozen) to amorphous (vitrified) by using high concentrations of cryoprotectants (at least 75% by weight) to suppress ice crystal formation. This allows the tissue to be preserved in a glass-like non-crystalline state, eliminating the harmful mechanical disruption caused by ice crystals while maintaining long-term storage capability.
Solution Approach 2:
The patent introduces cryoprotectants as intermediary substances that mediate between the tissue and the freezing process. These cryoprotectants (at least 75% by weight) act as mediators that prevent water molecules from organizing into ice crystals, thereby protecting the tissue structure during cryopreservation without requiring the tissue to be in direct contact with ice-forming conditions.
2Reliability
If traditional cryopreservation methods are used, then tissue preservation is achieved, but extracellular matrix integrity deteriorates and long-term function is compromised
Solution Approach 1:
The patent changes the preservation state from frozen to vitrified (amorphous solid) by using extremely high cryoprotectant concentrations (at least 75% by weight). This parameter change prevents the formation of ice crystals that would otherwise disrupt the extracellular matrix, thereby maintaining its integrity and the tissue's long-term functional stability.
Solution Approach 2:
The patent converts the potentially harmful effect of freezing into a beneficial vitrification process. By using high concentrations of cryoprotectants, the freezing process is transformed into a controlled vitrification where the tissue solidifies without ice crystal formation, turning what would be a damaging frozen state into a protective amorphous solid state that preserves extracellular matrix integrity.
3Duration of action of stationary object
If cryopreservation with controlled rate freezing is used, then long-term storage is enabled, but the process becomes complicated and expensive infrastructure is required
Solution Approach 1:
The patent changes the preservation approach from controlled-rate freezing to direct vitrification by using high concentrations of cryoprotectants (at least 75% by weight). This parameter change eliminates the need for complex controlled-rate freezing equipment and infrastructure, as the tissue can be directly vitrified and stored at simplified temperatures, reducing device complexity while maintaining long-term storage capability.
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 effectively preserves mammalian tissue matrices by preventing ice formation, reducing immune responses, and improving long-term function, while simplifying preservation, storage, and shipping processes, and is applicable to various medical applications.
Implementation Method 1
cooling the tissue in the solution having said cryoprotectant concentration of at least 75% by weight to a temperature between about -20°C and the glass transition temperature of the solution
Implementation Method 2
immersing the tissue in a solution having a cryoprotectant concentration of at least 75% by weight, and cooling the tissue in the solution having said cryoprotectant concentration of at least 75% by weight to a temperature between about -20°C and the glass transition temperature
Data Source
Figure 1A~1B
Figure 2A~3H
Figure 4A~4F
AI summary
Method for preserving tissue including immersing the tissue in a solution having a cryoprotectant concentration of at least 75% by weight, a cooling step where the tissue is cooled to a temperature between the glass transition temperature of the solution having a cryoprotectant concentration of at least 75% by weight and -20°C, a storage step where the tissue is stored at a temperature between the glass transition temperature of the solution and -2O°C, a rewarming step, where the tissue is warmed, and a washing step.