Cell Culture Flask Beveled Sidewall Shear Stress Reduction
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Solution Overview
Problem
Cell culture flasks currently face challenges in effectively aerating cell culture media without causing shear stress to sensitive cells, which can lead to reduced viability and increased foaming, hindering oxygen transfer and protein expression.
Innovation Solution
A cell culture flask design featuring a circumferential beveled or faceted portion with strategically placed baffles that minimize shear stress and foaming, enhancing oxygen exchange and cell growth while maintaining cell viability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If baffles are used to create turbulent flow to improve aeration and oxygen transfer, then oxygen transfer rate is improved, but cells experience higher levels of shear stress which is detrimental to cell viability
Solution Approach 1:
The patent applies curvature by replacing sharp-edged baffles with rounded or curved surface features. The curved geometry reduces flow separation and turbulence intensity near the walls, thereby minimizing shear stress on cells while maintaining adequate mixing and oxygen transfer throughout the culture medium.
Solution Approach 2:
The patent modifies the geometric parameters of the flask features, specifically using gradual transitions and optimized angles for the curved surfaces. By changing these parameters, the flow patterns are optimized to reduce localized high-shear zones while preserving bulk mixing efficiency and oxygen mass transfer.
2Quantity of substance
If aggressive baffles are used to improve aeration during shaking operations, then oxygen transfer is improved, but foaming of the cell culture medium occurs which hinders oxygen transfer
Solution Approach 1:
The curved surface features prevent the formation of sharp crests that lead to foam generation. By rounding the surfaces, the liquid flow becomes smoother and less prone to aerating excessively at the liquid-gas interface, thereby reducing foaming while maintaining effective aeration.
3Speed
If sharp features inside a shaker flask are used to create turbulence, then aeration is improved, but cells are easily stressed and damaged over a range of various shaker speeds
Solution Approach 1:
The curved features provide continuous turbulence generation across a wide range of shaking speeds without creating localized shock zones. The rounded geometry ensures that cells are exposed to gentler, more uniform shear fields even at high agitation speeds, thereby maintaining cell viability while achieving effective aeration.
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 design improves oxygen transfer and protein expression by reducing shear stress and foaming, allowing for effective cultivation of sensitive cells in larger volumes with comparable results to smaller scale controls.
Implementation Method 1
baffles can be used to create turbulent flow to improve aeration and oxygen transfer during agitation
Implementation Method 2
shaking of the flask creates a vortex that exposes more liquid surface to the oxygen in the headspace of the flask
Implementation Method 3
oxygen transfer takes place via two liquid surfaces within the shaker flask-a bulk liquid surface of the cell culture medium and a liquid film that forms on the wetted shaker flask sidewalls
Data Source
AI summary
A cell culture flask having a flask body that defines a cavity for receiving a cell culture medium is provided. The flask body includes an elongate neck that defines an opening to the cavity, a base, and a sidewall that extends from the elongate neck to the base of the flask body. The sidewall includes a circumferential beveled portion, which may or may not be faceted, that extends from an outermost periphery of the flask body to the base of the flask body at a constant angle relative to a central axis of the flask to define a sidewall angle.