RF Rewarming Control for Uniform Cryopreserved Tissue Heating
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Solution Overview
Problem
Current methods for cryopreservation of tissues and organs face challenges in preventing ice crystal formation, thermal gradients, and mechanical stress during rewarming, leading to tissue damage and non-viability, with no effective solution for large-scale samples.
Innovation Solution
A 2-parameter RF warming method using impedance matching and continuous frequency adjustment to achieve uniform, volumetric heating of cryopreserved tissues and organs, minimizing CPA toxicity and thermal mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high warming rates are used to prevent ice crystallization during rewarming, then crystallization is prevented, but thermal gradients cause mechanical stress and tissue fracturing
Solution Approach 1:
The rewarming process is divided into multiple temperature stages with different heating rates. The system transitions from rapid heating at lower temperatures to controlled heating at higher temperatures, preventing both crystallization and thermal shock by segmenting the thermal profile into distinct phases
Solution Approach 2:
The heating rate is dynamically adjusted based on the current temperature and tissue response. The system continuously monitors temperature and modifies the heating rate in real-time, transitioning from high to low heating rates as the tissue warms, preventing thermal gradients and mechanical stress while maintaining effective rewarming
2Object-affected harmful factors
If low CPA concentrations are used to minimize toxicity, then toxicity is reduced, but warming rates must be very high to prevent crystallization
Solution Approach 1:
The warming process is segmented into multiple temperature zones, each requiring different heating rates. This allows the use of lower CPA concentrations throughout the process while maintaining adequate warming rates in the critical subzero range to prevent crystallization
Solution Approach 2:
The system changes the heating rate parameter dynamically based on temperature. At lower temperatures where crystallization risk is highest, the system uses higher heating rates that compensate for lower CPA concentrations, while allowing slower heating at higher temperatures where toxicity becomes the primary concern
3Reliability
If high CPA concentrations are used to prevent crystallization, then crystallization is prevented, but CPA toxicity increases
Solution Approach 1:
The warming process is divided into critical and non-critical temperature ranges. In the critical subzero range, higher heating rates compensate for lower CPA concentrations, allowing the system to prevent crystallization without using toxic high CPA concentrations throughout the entire process
4Device complexity
If conventional heating methods are used for large samples, then equipment simplicity is maintained, but uniform heating cannot be achieved
Solution Approach 1:
The system uses dielectric heating through electromagnetic fields that cause molecular vibration and rotation in the tissue. This volumetric heating mechanism naturally provides uniform heating throughout large samples without requiring complex mechanical stirring or multiple heating sources
Solution Approach 2:
The patent replaces conventional mechanical heating methods with dielectric heating. This substitution allows uniform volumetric heating of large samples through electromagnetic field penetration, achieving heating uniformity without complex mechanical heating systems or multiple heat sources
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
The method enables rapid, uniform heating of large samples without crystallization or fracturing, achieving high viability rates by maintaining heating above the critical warming rate and minimizing thermal gradients.
Implementation Method 1
The present disclosure provides a method for thawing tissues, organs, arteries, cartilage, skin patches, and the like after cryopreservation. This improved electromagnetic thawing technique involves a heating mechanism that does not rely on diffusion of nanoparticles.
Implementation Method 2
The method uses a 2-parameter control for impedance matching with larger wavelengths for more uniform absorption (i.e., warming) by a sample.
Implementation Method 3
The present disclosure provides a method for thawing tissues, organs, arteries, cartilage, skin patches, and the like after cryopreservation. This improved electromagnetic thawing technique involves a heating mechanism that does not rely on diffusion of nanoparticles. The method uses a 2-parameter control for impedance matching with larger wavelengths for more uniform absorption (i.e., warming) by a sample.
Data Source
AI summary
A method for RF rewarming of cryopreserved tissues, organs, cartilage, arteries, and the like, whereby the samples are uniformly, volumetrically rewarmed to promote viability. The method maintains a warming rate above the critical warming rate of a CPA, preferably DP6 or VS55, during the critical warming period (−80° C. to −30° C.) and does not produce cracks, crystallization, or destructive thermal gradients during devitrification. The method also minimizes CPA toxicity. The method controls frequency and impedance matching to keep the system at resonant frequency and an input impedance of 50 Ω.