Bioreactor Filter Pocket With Low Swelling Medium

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Solution Overview

Problem

Existing bioreactors face challenges with mechanical stability of perfusion filters during long-term use and impaired gas exchange due to filter warping and folding, which leads to mechanical stress and reduced efficiency in cell culture processes.

Innovation Solution

A bioreactor design featuring a filter pocket fixed to the inner surface with a hydrophilic or hydrophobic filter medium that minimizes swelling and folding, ensuring mechanical stability and unimpeded gas exchange, utilizing a hydrophilic filter medium with a degree of swelling and shrinkage of no more than 1% and reinforced with porous fabrics for enhanced durability and filtration efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a filter medium with large pore size is used for high permeability, then perfusion efficiency is improved, but mechanical strength and resistance to folding are reduced

Engineering Contradiction:
Improveperfusion efficiencyVSAvoidmechanical strength of filter medium
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The filter module uses a composite structure combining a porous substrate (for filtration) with a reinforcing mesh or skeleton (for mechanical strength). This allows the filter medium to maintain both high permeability for efficient perfusion and sufficient mechanical strength to resist folding and damage during continuous operation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The filter medium is designed as a flexible but mechanically robust membrane that can conform to the bioreactor wall while maintaining its structural integrity. The flexible design allows it to withstand pressure differences and mechanical stress without folding or breaking, while the porous structure maintains high permeability for cell-free medium removal.

Inventive Principle:
Principle #30Flexible shells and thin films

2Productivity

If the filter medium is made highly permeable with large void volume, then cell-free medium removal is improved, but the filter medium develops distortions and folds leading to breakage

Engineering Contradiction:
Improvecell-free medium removal rateVSAvoidfilter medium durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The combination of porous filtration material with a reinforcing structural network provides both the high permeability needed for efficient cell-free medium removal and the mechanical stability required to prevent folding and breakage during prolonged operation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The filter medium's physical parameters are optimized by controlling pore size distribution, thickness, and mechanical properties to achieve a balance between permeability for high productivity and structural integrity for long-term reliability in continuous perfusion operation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a floating filter module is used for perfusion, then installation is simplified, but gas exchange with the culture medium is impaired

Engineering Contradiction:
Improvefilter module installationVSAvoidgas exchange efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

Instead of using a floating filter module that creates a physical barrier between gas and culture medium, the invention integrates the filter directly into the bioreactor wall structure. This eliminates the floating component while maintaining perfusion functionality, allowing uninterrupted gas exchange at the gas-liquid interface.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The filter medium is merged with the bioreactor wall structure rather than being a separate floating component. This integration eliminates the floating module that would impede gas exchange, while the filter continues to perform its separation function at the wall interface.

Inventive Principle:
Principle #5Merging (Combining)

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 solution provides a mechanically stable and efficient perfusion system that prevents filter medium damage and maintains effective gas exchange, ensuring prolonged operation without filter warping or blockages, thereby supporting high-density cell culture processes.

Implementation Method 1

at least one filter pocket wall is at least partially formed by a hydrophilic filter medium... even with a filter pocket covering an entire wall of the bioreactor, wrinkling of the filter medium is avoided if the filter medium has a swelling and/or shrinkage coefficient of no more than 1% in water

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

The cell-free culture medium is separated by a filtration module in the form of a filter bag, consisting of a large-pore filter medium whose periphery is welded to one of the inner bioreactor walls

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2268788B1Bioreactor
Publication Date: 2016.07.20 SARTORIUS STEDIM BIOTECH GMBH
  • EP2268788B1 patent drawingFigure 1
  • EP2268788B1 patent drawingFigure 2

AI summary

The invention relates to a bioreactor for cultivating cells having a filter bag for separating culture fluid and cells, the filter medium of the filter bag having a degree of swelling of less than 1%. The bioreactor according to the invention is characterized by a high durability of the filter bag thereof.