Semipermeable Membrane Cryopreservation Device for Ice Damage Control
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Solution Overview
Problem
Traditional cryopreservation methods cause significant mechanical damage to biological samples due to ice crystal formation, leading to low viability and impaired function, particularly in tissues like corneas, and there is no effective device to prevent this damage during cryopreservation.
Innovation Solution
A cryoprotective device with a semi-permeable membrane that prevents large ice crystals from forming inside the sample by allowing only smaller crystals to pass through, using a porous membrane to separate the sample from external ice formation, thereby minimizing mechanical damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If traditional cryopreservation methods are used to store biological samples at low temperatures, then long-term storage is achieved, but mechanical damage from ice crystal formation causes low viability and impaired function
Solution Approach 1:
A semi-permeable membrane is introduced as an intermediary barrier between the biological sample and the external environment. The membrane allows small water molecules to pass through via osmosis while blocking larger ice crystals, thereby preventing mechanical damage from extracellular ice formation during cryopreservation while maintaining long-term storage capability
Solution Approach 2:
A porous semi-permeable membrane with specific pore size is used to create a physical filter that selectively permits passage of small molecules (water) while preventing passage of larger structures (ice crystals). The membrane's pore diameter is specifically chosen to be smaller than the critical ice crystal size that causes mechanical damage to cells
2Reliability
If high concentrations of cryoprotectants are used to prevent ice formation, then cell viability is improved, but osmotic damage and toxicity increase
Solution Approach 1:
The harmful cryoprotectant chemicals are extracted from the system and replaced with a physical barrier approach. Instead of using chemical agents that cause osmotic stress and toxicity, the invention uses a semi-permeable membrane to physically prevent ice crystal formation, thereby maintaining cell viability without the harmful side effects of high-concentration cryoprotectants
Solution Approach 2:
The chemical mechanism of cryoprotectants is replaced with a physical-mechanical system. Rather than relying on chemical substances to alter freezing points and prevent ice formation, the invention uses the mechanical barrier of a semi-permeable membrane to physically block ice crystal growth, substituting chemical action with physical structure
3Reliability
If slow freezing method is used to reach storage temperatures, then ice crystal formation is controlled, but the process is time-consuming and facility demanding
Solution Approach 1:
The semi-permeable membrane is pre-installed around the biological sample before freezing begins. This preliminary preparation ensures that as ice crystals form during rapid freezing, they are immediately blocked by the pre-positioned membrane barrier, eliminating the need for slow, controlled freezing processes and enabling rapid cryopreservation while maintaining ice crystal control
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 device significantly reduces mechanical damage to biological samples by controlling ice crystal size, enhancing cryopreservation efficiency and viability, especially for tissues like corneas, without the need for cryoprotectants.
Implementation Method 1
the housing comprises a semi-permeable membrane, the membrane being impermeable to ice crystals that are significantly larger than an average pore size of the membrane
Implementation Method 2
a porous membrane to separate the sample from external ice formation
Implementation Method 3
ice crystal size control during cryopreservation
Implementation Method 4
ice formation control technologies
Data Source
AI summary
A cryoprotective device protects an aqueous biological material from mechanical damage due to ice formation during cryogenic freezing and/or cryostorage by preventing direct contact of the biological material with cell-damaging large ice crystals, the cryoprotective storage device having a housing with an internal cavity. The housing is configured to receive a freezable medium with the biological material within the internal cavity. The housing includes a semi-permeable membrane. The membrane is impermeable to ice crystals that are larger than an average pore size of the membrane to prevent such ice crystals from passing into the internal cavity from outside the housing, such that ice crystals formed in the medium within the housing have a smaller crystal size from ice crystals formed in the medium outside of the housing. As such, the biological material is protected from mechanical damage generated by direct contact with large ice crystals.