Hepatocyte Cryopreservation Viability via Density Gradient
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Solution Overview
Problem
Current methods for cryopreserving hepatocytes result in significant viability loss and variability in liver enzyme expression, limiting their availability and reliability for medical research and therapeutic applications.
Innovation Solution
A method involving density gradient fractionation, specifically Percoll density centrifugation, is used to separate viable hepatocytes from non-viable ones, allowing for repeated cryopreservation and thawing with greater than 70% viability, and enabling the creation of pooled hepatocyte preparations with consistent metabolic activities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If hepatocytes are cryopreserved using conventional methods, then storage is enabled, but viability decreases significantly (25-35% recovery)
Solution Approach 1:
The patent modifies the cryopreservation parameters by using a two-stage freezing process with specific temperature profiles (-1°C/min to -5°C/min initially, then -20°C/min to -40°C/min), optimized cryoprotectant concentrations (10% DMSO, 90% fetal bovine serum), and controlled thawing rates to maximize cell survival while enabling long-term storage
Solution Approach 2:
The patent introduces cryoprotectants (DMSO and fetal bovine serum) as intermediary substances that mediate between the cell membrane and the freezing environment, preventing ice crystal formation and membrane damage, thereby maintaining cell viability during cryopreservation and enabling extended storage duration
2Adaptability or versatility
If hepatocytes are cryopreserved, then availability for later use is improved, but variability in liver enzyme expression increases
Solution Approach 1:
The patent applies preliminary action by pre-treating hepatocytes with cryoprotectants and establishing optimized freezing protocols before storage, which stabilizes cellular metabolism and enzyme expression profiles, reducing variability when cells are thawed and used for different applications
Solution Approach 2:
The patent controls physical parameters including freezing rate (-1°C/min to -40°C/min), storage temperature (-196°C liquid nitrogen), and thawing conditions to maintain enzyme expression stability while enabling hepatocytes to be stored and deployed with high availability across multiple studies
3Ease of operation
If fresh hepatocytes are obtained from liver resections or donors, then immediate use is possible, but supply is inconsistent and geographically limited
Solution Approach 1:
The patent implements preliminary cryopreservation of hepatocytes immediately after isolation from liver resections or donors, creating a stable cell bank that can be stored long-term and shipped globally, thereby maintaining immediate usability while dramatically improving supply consistency and geographic accessibility
Solution Approach 2:
The patent creates frozen copies of fresh hepatocytes that can be stored and transported without degradation, allowing researchers worldwide to access consistent cell preparations without needing immediate access to fresh surgical specimens, thus resolving the geographic and supply consistency limitations
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 the production of stable and reproducible hepatocyte preparations that can be repeatedly cryopreserved and thawed with high viability, facilitating their use in medical research and therapeutic applications by minimizing viability loss and enzyme expression variability.
Implementation Method 1
subjecting hepatocytes that have been frozen and thawed to density gradient fractionation (especially percoll density centrifugation) to separate viable hepatocytes from non-viable hepatocytes
Implementation Method 2
cryopreserving the recovered viable hepatocytes to thereby form the desired preparation of hepatocytes
Data Source
AI summary
The present invention relates to novel cell (e.g., hepatocyte, etc.) compositions and methods for their preparation and use. In particular, the invention concerns methods of processing preparations of such cells so as to permit their repeated cryopreservation and thawing while retaining substantial viability. The invention also concerns preparations of cells (e.g., hepatocytes) that have been repeatedly cryopreserved and thawed.