Microcarrier Bioreactor for hPSC Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for large-scale production of human pluripotent stem cells (hPSCs) face challenges in scalability, cost-effectiveness, and maintaining high cell quality, particularly in achieving high cell densities and efficient expansion while avoiding the need for 2D seed trains and minimizing contamination risks.
Innovation Solution
A microcarrier-based bioreactor suspension platform with a closed, automated process for hPSC expansion using xeno-free, fully defined medium, allowing for high-fold expansion without passaging during incubation, and enabling cryopreservation and direct inoculation into larger bioreactors, thereby eliminating the need for 2D seed trains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 2D cell culture platforms are used to achieve high cell densities, then cell quality is maintained, but scalability and cost-effectiveness deteriorate due to extensive manual effort, laboratory space and personnel requirements
Solution Approach 1:
The patent transitions from two-dimensional (2D) culture to three-dimensional (3D) microcarrier suspension culture. This dimensional change enables scalable expansion while maintaining cell quality, as the 3D microcarrier system provides adequate surface area for cell attachment and growth without the space constraints of 2D culture, achieving both high cell density and scalability
2Reliability
If aggregate-based 3D culture is used to provide physiologically relevant microenvironment, then cell differentiation quality improves, but scalability deteriorates due to requirement for sequential passaging and small molecule Y27632
Solution Approach 1:
The patent employs disposable microcarriers that can be used for single-use expansion without requiring sequential passaging. This eliminates the need for repeated handling and small molecule additives like Y27632, simplifying the process while maintaining the benefits of 3D culture for cell differentiation quality
Solution Approach 2:
The patent introduces microcarriers as an intermediary substrate that provides the necessary surface for cell attachment and growth in suspension culture. These microcarriers serve as a mediator between the cells and the culture medium, enabling 3D expansion without the complexity of aggregate-based systems
3Productivity
If microcarrier-based culture systems are used to facilitate scalability, then productivity improves, but contamination risk increases due to open systems and multiple handling steps
Solution Approach 1:
The patent implements a continuous, closed-system microcarrier suspension culture that minimizes opening and handling steps. The system maintains continuous culture conditions with automated media exchange and monitoring, reducing exposure to contamination while preserving the scalability benefits of microcarrier-based expansion
4Quantity of substance
If sequential passaging is performed to achieve high fold expansion in aggregate culture, then cell quantity increases, but time and labor requirements increase
Solution Approach 1:
The patent performs preliminary attachment of cells to microcarriers in a controlled manner before scaling up expansion. This preliminary action on microcarriers enables subsequent continuous expansion without repeated passaging, reducing both time and labor requirements while achieving high fold expansion
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 platform achieves >2×10^9 cells/L with high self-renewal and pluripotency, efficient expansion, and maintains cell quality through automated harvesting and concentration, reducing contamination risks and labor requirements, while allowing for direct differentiation into various cell types.
Implementation Method 1
microcarrier-based bioreactor suspension platform for hPSC expansion
Implementation Method 2
incubating the pluripotent stem cells in the bioreactor for a period of time sufficient to yield a fold expansion of about 50 times or greater
Implementation Method 3
concentrating the expanded pluripotent stem cells
Implementation Method 4
cryopreserving the expanded pluripotent stem cells
Data Source
AI summary
A closed, automated and scalable stirred tank bioreactor platform, capable of sustaining high fold expansion of hPSCs is provided. hPSCs are expanded in a controlled bioreactor using perfused xeno-free media. Cell harvest and concentration are performed in closed steps. The hPSCs can be cryopreserved to generate a bank of cells or further processed as needed. Cryopreserved cells can be thawed into a 2D tissue culture platform or a 3D bioreactor to initiate a new expansion phase or be differentiated to the clinically relevant cell type. The expanded hPSCs express hPSC-specific markers, have a normal karyotype and the ability to differentiate to the cells of the three germ layers. This end-to-end platform allows large expansion of high quality hPSCs that can support the required cell demand for various clinical indications.