Numerical Simulation and Comparison of Flow Field in Different Dynamic Co-Culture Conditions.

Bioreactor technology facilitates the gradual automation of cell expansion and the development of biofunctional synthetic alternatives. However, it is difficult to fully understand the flow field and force field environments formed in it by experimental means. Computational fluid dynamics (CFD) offers a robust framework for analyzing and understanding the impacts of fluid flow, material diffusion, and fluid shear stress (FSS) on in vitro cell and tissue regeneration dynamics. In this study, the FLUENT software is used to simulate and calculate the flow field environment of the rotary cell culture system (RCCS) and spinner flask (SF), including dynamic pressure, shear stress, and velocity distribution. Particles of two diameters for three-dimensional cell culture were randomly arranged in different radial/axial positions, and the FSS on the particles in RCCS and SF at different rotational speeds was also analyzed. It is expected to visualize the flow field distribution of the bioreactor and local hydrodynamic changes near the particles, and provide positive assistance for the dynamic culture/co-culture of different cells-microcarriers complex. The distribution of FSS on randomly arranged L and S particles was analyzed in detail to evaluate and screen the suitable operating conditions of these two bioreactors. Visually understanding the flow field distribution and local hydrodynamic changes within the bioreactor is expected to provide positive assistance for dynamic culture. The particles may periodically contact the fresh oxygenated medium during rotation with the fluid. Two fluid circulations in SF were generated in the upper/lower area of the blade, and a relatively static fluid circulation area was formed at the bottom with low velocity and pressure in the center, which was not conducive to material exchange. Rotary bioreactors may be more suitable than spinner flasks as a dynamic culture tool for some types of cells or other constructs.