Ps-85: Computational Fluid Dynamics Model to Optimize Air-Lift Bioreactor Geometry for Stem Cell Expansion (Pages: 55-55)


Nabavinia M *, Alizadeh R , Khoshfetrat AB ,

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Objective: Air-lift bioreactors can play an important role in tissue engineering because of many advantages, such as; simplicity of construction, absence of moving parts, easy sterilization and low power consumption. However, optimum design of airlift bioreactors for cultivation of stem cells is still a difficult task, because of complicated relations between mixing and mass transfer, and also high sensitivity of stem cells to shear stress. In this study, computational fluid dynamics (CFD) analysis using related software was used to characterize an internal loop airlift bioreactor for stem cell proliferation. The effect of geometry parameters such as sparger position and configuration, ratio of the downcomer to the riser area (Ad/Ar), and height of liquid above (Ha) and below (Hb) of the draft tube was considered to identify the complex hydrodynamic environment as well as shear stress applied to suspension culture of stem cells. The results demonstrated that sparger position and configuration has maximum effect on shear stress exposure on cell although shear stress can be reduced with increasing Ha in this area. In addition, large Ad/Ar was found to be useful for minimum exposure shear stress on cells while it has negative effect on cell distribution as same as Hb . Therefore, optimum design of air-lift bioreactor can be achieved by CFD analyzing with comprehensive considering of hydrodynamic environment to apply this type of bioreactor in tissue engineering without performing costly time-consuming experiments. Materials and Methods: Computational fluid dynamic software (ANSYS 14.0) was used to consider geometric parameters of air-lift bio-reactor hydrodynamic environment to apply this kind of bio-reactor in tissue engineering for expanding stem cells. Results: The effect of geometry parameters such as sparger position and configuration, ratio of the downcomer to the riser area (Ad/Ar), and height of liquid above (Ha) and below (Hb) of the draft tube was considered to identify the complex hydrodynamic environment as well as shear stress applied to suspension culture of stem cells. The results demonstrated that sparger position and configuration has maximum effect on shear stress exposure on cell because of effected on bubble formation and geometry. Although shear stress can be reduced with increasing Ha in this area, in addition, large Ad/Ar was found to be useful for minimum exposure shear stress on cells while it has negative effect on cell distribution as same as Hb . Conclusion: As the above results show, optimum design of air-lift bio-reactor can be achieved by CFD analyzing with comprehensive considering of hydrodynamic environment to evaluate applicability of air-lift bio-reactor in tissue engineering without performing costly time-consuming experiments.