Membrane Bioreactor Layout for Low-Shear T-Cell Expansion
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Solution Overview
Problem
Existing bioreactors for expanding T-cells face challenges with scalability and require high media volumes, leading to shear stress and inefficient media exchange, which hinders cell growth and expansion.
Innovation Solution
A bioreactor design with permeable membranes and flow channels that allow nutrient and gas diffusion while retaining cells, using porous and dense membranes to facilitate expansion without disturbing the cell population, combined with a pump assembly for controlled media flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If static bioreactors are used for T-cell expansion, then gas diffusion to T-cells can be achieved, but scalability is limited and process control is difficult due to difficulty in rapidly replacing perfusion media
Solution Approach 1:
The bioreactor is divided into distinct functional zones: a first chamber for cell culture, a second chamber for media reservoir, and multiple flow channels separated by membranes. This segmentation allows independent optimization of each zone - cells remain undisturbed in the first chamber while media is efficiently exchanged in the second chamber, resolving the contradiction between maintaining cell culture stability and achieving scalable media replacement.
Solution Approach 2:
Permeable membranes serve as intermediaries between the cell culture chamber and media flow channels. These membranes allow selective passage of nutrients, gases, and waste products while physically isolating cells from direct media flow. This intermediary structure enables scalable media exchange without disturbing the cell population, directly addressing the limitation of static bioreactors.
2Productivity
If hollow-fiber bioreactors are used for protein extraction, then perfusion media can be removed, but a lot of shear stress is applied to T-cells, thereby hindering the growth and expansion of T-cells
Solution Approach 1:
The system separates the media exchange function into a dedicated second chamber with flow channels, distinct from the first chamber where T-cells are cultured. This spatial segmentation ensures that high-velocity media flow occurs only in the second chamber, while T-cells in the first chamber experience minimal flow disturbance, eliminating shear stress while maintaining efficient media exchange.
Solution Approach 2:
The permeable membrane acts as an intermediary that transfers nutrients and removes waste between chambers without requiring direct contact between media and cells. This allows aggressive media perfusion in the second chamber to achieve high exchange efficiency while the first chamber maintains a quiescent environment protective of T-cell growth.
3Illumination intensity
If high media volumes are used in static bioreactors, then appropriate gas diffusion can be achieved, but the seeding cell density must be higher, which increases operational complexity
Solution Approach 1:
The invention transitions from three-dimensional suspension culture in large media volumes to a two-dimensional interface culture on membrane surfaces. T-cells are seeded on the permeable membrane in the first chamber, creating a high surface-area-to-volume ratio that enhances gas and nutrient diffusion efficiency. This dimensional change allows lower seeding densities while achieving superior mass transfer compared to traditional static bioreactors.
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 bioreactor enables efficient expansion of T-cells with minimal disturbance, allowing scalable and controlled media exchange, enhancing cell yield and reducing operational complexity.
Implementation Method 1
The first membrane is substantially permeable to one or more of nutrient, reagent, and gas contained within the first media and waste produced by the population of biological cells
Implementation Method 2
The first membrane is substantially permeable to one or more of nutrient, reagent, and gas contained within the first media
Implementation Method 3
The bioreactor may further comprise a pump assembly configured to move the first media through the first flow channel
Data Source
AI summary
A bioreactor for expanding a population of biological cells comprises a housing having an interior cavity and a first membrane affixed within the housing. The first membrane divides the interior cavity into a chamber and a first flow channel. The bioreactor further comprises a cell culture surface contained within the chamber on which the population of biological cells may be disposed, a first inlet port fluidly coupled to the first flow channel, such that first media can be flowed into the first flow channel, and a first outlet port fluidly coupled to the first flow channel, such that the first media can be flowed out of the first flow channel. The first membrane is substantially permeable to one or more of nutrient, reagent, and gas contained within the first media and waste produced by the population of biological cells, while being substantially impermeable to the population of biological cells.