Angled Curved Impeller for Low Shear Cell Suspension
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Solution Overview
Problem
Existing impellers for stirring microcarrier beads in cell culture are unable to efficiently lift cells and beads at low rotational speeds, leading to excessive shear forces that damage cells and disrupt adhesion, and fail to effectively separate cells from beads without causing injury.
Innovation Solution
An impeller design with angled blades, featuring a planar and curved surface, is used to maintain microcarrier beads in suspension at low rotational speeds, minimizing shear forces and facilitating efficient cell growth and separation by creating a gentle agitation environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high rotational speeds are used to lift microcarrier beads into suspension, then the beads are effectively mixed and suspended, but excessive shear forces damage cells and disrupt adhesion between cells and beads
Solution Approach 1:
The impeller blades are designed with a curved surface that is angled at 70-120° to the planar portion, creating a gentle agitation environment that lifts beads into suspension through curved motion paths rather than harsh radial forces, thereby reducing shear damage to cells
Solution Approach 2:
The invention changes the geometric parameters of the impeller blades, specifically the angle between the planar and curved surfaces (70-120°), to optimize the flow patterns and lifting action, enabling effective suspension at lower rotational speeds that minimize cellular injury
2Productivity
If standard impellers are used to separate cells from microcarrier beads, then separation can be achieved, but excessive shear forces cause cell injury and loss of adhesion
Solution Approach 1:
The curved surface on the impeller blades creates gentle agitation during the separation process, allowing cells to be detached from beads through controlled fluid motion rather than harsh mechanical forces, thereby maintaining cell integrity and adhesion properties
3Object-affected harmful factors
If low rotational speeds are used to minimize shear forces, then cell damage is reduced, but the impeller cannot efficiently lift cells and beads into suspension
Solution Approach 1:
The angled curved surface on the impeller blades creates more effective lifting action at lower rotational speeds by optimizing the flow patterns and reducing the energy required to suspend beads, thereby achieving both gentle handling and efficient mixing
Solution Approach 2:
By optimizing the geometric parameters of the impeller blades, specifically the angle between planar and curved surfaces (70-120°), the system achieves enhanced suspension lifting efficiency at lower rotational speeds, minimizing cellular injury while maintaining productivity
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 impeller effectively maintains cells and microcarrier beads in suspension at low rotational speeds, reducing cellular injury and improving cell growth yields while enabling efficient separation of cells from beads without causing damage.
Implementation Method 1
The impeller is rotated at a speed of 10 to 55 rpm. The use of such low rotational speeds maintains the cells and suspension without causing any injury to the cells.
Data Source
AI summary
The invention relates to an impeller for use in a bioreactor for growing adherent mammalian cells and/or a cell separator for adherent mammalian cells. The impeller of the invention is designed to efficiently and rapidly lift a bed of settled cells and microcarrier beads at low rotational speeds. Cell growth and concomitant yield is therefore improved by maintaining the culture in an environment of low shear force.