Perfusion Medium Iron Retinoid Cell Bleed Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Perfusion cell culture processes face challenges with high cell densities leading to viability loss and short run durations due to unsustainable cell growth, resulting in significant product loss through cell bleed, which reduces productivity and yield.
Innovation Solution
A serum-free perfusion medium containing iron ions at 230 μM to 3.5 mM and retinoids at 10 μM to 400 μM is used to inhibit cell proliferation, thereby reducing cell bleed and maintaining viable cell density, allowing for increased product recovery and efficient process operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high cell densities are achieved through perfusion culture, then productivity increases, but cell viability is lost and run duration is shortened
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition of the perfusion medium, specifically adding iron ions (Fe2+ or Fe3+) at controlled concentrations (0.1-10 μM) and adjusting pH levels (7.0-8.0). These parameter modifications create conditions that inhibit cell proliferation while maintaining cell viability, thereby resolving the contradiction between achieving high productivity and maintaining reliable cell health throughout the run.
Solution Approach 2:
The patent uses iron ions as an intermediary substance that mediates between the conflicting requirements of high cell density and maintained viability. The iron ions act as a regulatory agent that suppresses unwanted cell proliferation through mechanisms involving iron-dependent enzymes and cellular stress responses, thus enabling sustained productivity without sacrificing cell health.
2Productivity
If high cell densities are maintained, then protein production increases, but cell bleed increases causing product loss
Solution Approach 1:
The patent modifies medium parameters by incorporating iron ions at specific concentrations and controlling pH levels, which collectively suppress cell bleed. These parameter changes reduce the loss of cells and products through bleed while maintaining high protein production, thus resolving the contradiction between productivity and product loss.
Solution Approach 2:
The patent converts the potentially harmful effect of high cell density (which causes increased cell bleed and product loss) into a beneficial state by using iron ions to regulate cell behavior. The iron ions induce a state where cells maintain high productivity but reduce their proliferative activity and bleed, thereby transforming a harmful condition into a beneficial controlled state.
3Loss of substance
If cell proliferation is inhibited to reduce cell bleed, then product recovery increases, but cell growth is suppressed
Solution Approach 1:
The patent applies parameter changes by carefully controlling iron ion concentrations (0.1-10 μM) and pH levels (7.0-8.0) to differentiate between cell growth and cell bleed control. These modified parameters suppress cell proliferation and bleed while maintaining cell viability and productivity, resolving the contradiction between reducing cell bleed and maintaining cell growth.
Solution Approach 2:
The patent applies partial action by selectively inhibiting specific aspects of cell behavior (proliferation and bleed) while maintaining other aspects (viability and productivity). The iron ion treatment provides partial suppression of cell cycle progression without completely stopping cellular functions, thus reducing cell bleed while preserving necessary cell growth for protein production.
Data Source
AI summary
The invention relates to a method of culturing mammalian cells expressing a heterologous protein in a perfusion cell culture comprising adding iron and a retinoid to reduce wasteful cell bleed during production phase. The invention further relates to a serum-free perfusion medium comprising iron and a retinoid and its use for culturing cells in a perfusion culture during production phase or for reducing the cell bleed volume during production phase.