Numerical simulation of coupled cell motion and nutrient transport in NASA's rotating bioreactor

摘要

Rotating bioreactor, such as the NASA bioreactor, which was designed by the National Aeronautics and Space Administration (NASA), USA, can be used to mimic micro-gravity conditions and simulate the effects of microgravity on cells growth. The cell growth in the bioreactor depends on the nutrient availability which in turn depends on the cell density and distribution within the bioreactor. In this work, we use a numerical model of suspended particle motion to simulate the cell motion and distribution in a specific variant of the NASA bioreactor, namely, the high aspect ratio vessel (HARV) bioreactor. The nutrient distribution in the bioreactor is simulated based on a convection-diffusion-reaction supplemented by laboratory experiments aimed at obtaining the required data. We present the modelling framework in this paper and discuss the most salient simulated results. For example, the simulation results show that the distributions of the cells in the bioreactor appear as concentric circles and that the cells density is higher in the middle of the HARV bioreactor. These cell distributions imply that they may accumulate in the middle of the bioreactor at sufficiently high cell density. The results also demonstrate that the concentration of nutrient is fairly uniform in the bioreactor but decreases slightly from the outer radius of the HARV bioreactor to the inner radius. This is possibly caused by the higher consumption of glucose due to the higher cell density in the middle of the radius. We expect that the modelling framework in this paper would help optimise the culture conditions for the cells in HARV bioreactors.