RWPV bioreactor mass transport: earth-based and in microgravity

Area of Science:

• Bioreactor Engineering
• Cell Culture Technology
• Mass Transport Phenomena

Background:

• The NASA Rotating Wall Perfused Vessel (RWPV) bioreactor is used for cell culture under simulated microgravity and ground-based conditions.
• Understanding mass transport and mixing is crucial for optimizing cell culture performance and experimental outcomes.

Purpose of the Study:

• To numerically model and analyze mass transport and mixing of scalar quantities in the RWPV bioreactor.
• To compare vessel performance under microgravity versus ground-based operating conditions.
• To investigate the transport of oxygen for colon cancer cells cultured in the RWPV.

Main Methods:

• Numerical modeling of the flow field and scalar concentration field within the RWPV.
• Simulation of operating conditions for both microgravity and ground-based cell cultures.
• Analysis of oxygen transport, considering cell densities and consumption rates.

Main Results:

• Microgravity operation leads to significantly shorter mixing times compared to ground-based operation.
• Increased differential rotation rates (microgravity) enhance mixing and transport; increased mean rotation rates (ground-based) suppress them.
• Higher perfusion rates improve mass transport, but diminishing returns are observed above 5-10 cc/min.

Conclusions:

• The RWPV bioreactor provides a well-mixed environment under microgravity conditions, even at minimal perfusion rates.
• Exit concentration is an unreliable indicator of internal concentration distribution within the vessel.
• Microgravity conditions in the RWPV offer superior mass transport and mixing compared to ground-based operations.