Cell Culture Bag Filter Arrangement for Stem Cell Expansion
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Solution Overview
Problem
Current methods for expanding stem cells, such as those described in WO2009/139703, require pre-culturing in a T-flask, which incurs high material and manpower costs, and poses contamination risks, making them unsuitable for field use, especially in treating tissue disorders like cardiovascular disease and bone defects.
Innovation Solution
A cell-culture-bag system that provides a closed bioreactor environment for expanding stem cells directly from a crude biopsy, using a filter arrangement with specific mesh sizes to separate red blood cells and microcarriers, allowing for a single bioreactor environment suitable for field use, such as in hospitals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pre-culturing in T-flask is used to expand stem cells, then sufficient cell quantity is achieved, but material costs and manpower costs increase significantly
Solution Approach 1:
The patent combines the pre-culturing step and the expansion step into a single bioreactor system. The crude biopsy is directly inoculated into the bioreactor with microcarriers, eliminating the need for separate T-flask pre-culturing. This merging of operations reduces both material costs (fewer flasks, media, and reagents) and manpower costs (fewer handling and transfer operations requiring skilled technicians).
Solution Approach 2:
The bioreactor system segments the cell expansion process into distinct functional zones: a seeding chamber for initial cell attachment to microcarriers and a main expansion chamber for bulk culture. This segmentation allows direct processing of crude biopsy without intermediate T-flask steps, achieving cost reduction while maintaining sufficient cell quantity production.
2Quantity of substance
If multiple processing steps (purification, pre-culturing, transfer) are performed, then stem cells are adequately prepared, but contamination risk increases
Solution Approach 1:
The patent merges multiple processing steps into a single closed bioreactor system. The crude biopsy is directly inoculated into the bioreactor, and all subsequent culturing and expansion occur within this closed environment. This eliminates intermediate transfer steps between T-flasks and the bioreactor, significantly reducing contamination risk while still achieving adequate cell preparation through the integrated seeding and expansion process.
Solution Approach 2:
The bioreactor acts as an intermediary closed system that receives crude biopsy directly and processes it without requiring intermediate open manipulations. The filter arrangement with specific mesh sizes serves as a mediator to separate red blood cells and microcarriers while maintaining the closed environment, thus reducing contamination risk throughout the processing sequence.
3Quantity of substance
If multiple transfer steps are performed between T-flask and bioreactor, then cell pre-seeding is achieved, but the process becomes complex and unsuitable for field use
Solution Approach 1:
The patent combines the pre-seeding function and expansion function into a single bioreactor operation. The crude biopsy is directly inoculated into the bioreactor containing microcarriers, and the entire process from pre-seeding to expansion occurs within this single device. This merging dramatically simplifies the process, making it suitable for field use in hospitals without requiring complex multiple transfer steps between different vessels.
Solution Approach 2:
The bioreactor is designed as a universal system that performs multiple functions: it serves as both the pre-seeding chamber and the expansion chamber. The filter arrangement with adjustable mesh sizes provides multi-functionality in cell separation and medium filtration. This universal design reduces process complexity and enables field deployment while achieving adequate cell pre-seeding and expansion.
4Quantity of substance
If fine mesh filter (8-20μm) is used to block stem cells, then red blood cells are effectively separated, but filter clogging risk increases
Solution Approach 1:
The patent segments the filtration function into two distinct stages with different mesh sizes: a coarse filter (50-100μm) for initial separation of microcarriers and a fine filter (8-20μm) for red blood cell separation. This segmentation allows each filter to operate at optimal mesh size for its specific function, reducing the risk of clogging in the fine filter by pre-removing larger particles that would obstruct the finer pores.
Solution Approach 2:
The coarse filter performs preliminary action by removing microcarriers and larger particles before the cell suspension reaches the fine mesh filter. This preliminary filtration prevents clogging of the fine filter while still achieving effective red blood cell separation, maintaining reliability throughout the filtration process.
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 system reduces costs and contamination risks, enabling efficient expansion of stem cells from a crude biopsy within a single bioreactor environment, making it suitable for clinical use and improving the feasibility of stem cell treatments in various tissue disorders.
Implementation Method 1
the filter arrangement filters the fluid path from the chamber to the first outlet with a relatively fine mesh size of preferably 8-20μm
Implementation Method 2
the filter arrangement filters the fluid path from the chamber to the third outlet with a relatively coarse mesh size of preferably 50-100μm
Data Source
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AI summary
A cell-culture-bag for use in the expansion of stem cells from a crude biopsy, comprising: outer walls; a chamber located within the walls; a first inlet, and first and second outlets, providing fluid communication with the chamber, for connection to a perfusion apparatus; and a filter arrangement constructed to allow passage of red blood cells and block passage of stem cells from the first outlet, and block passage of microcarriers from the second outlet.