Computational simulation on mechanical stimulation of stem cells due to fluid shear flow in a bioreactor using bone scaffolds

IntroductionOne of the challenges regarding to bone tissue engineering is to design and fabricate biologically optimum porous scaffolds. Consolidation of CAD with advance additive manufacturing (3D printing) facilitates the production of the bone scaffolds with excellent structural properties. Putting the scaffold in a dynamic cell culture, such as perfusion bioreactor, makes the role of mechanical parameters such as shear stress and hydrodynamic pressure more important. On the other hand, these mechanical parameters are influenced by the scaffold architecture. ObjectivesIn this study, effects of bone scaffold architecture on mechanical stimuli were analyzed and the resulting mesenchymal stem cell fate was predicted.MethodsThe fluid has been considered as the cell culture medium, a Newtonian fluid. Young’s modulus of the human mesenchymal stem cells (located on the scaffold surfaces) undergoing osteogenic differentiation was assumed in the model. Bone scaffolds based on mathematical functions of minimal surfaces were designed and exposed in a dynamic cell culture medium. Finite element method was used for discretization of the numerical models. Simulation of the fluid flow through the scaffolds was done using computational fluid dynamics and fluid-structure interactions.ResultsIt was elucidated that the scaffold microstructure and pore architecture have an important effect on accessibility of the fluid to different portions of the scaffold. This leads to optimization of shear stress and hydrodynamic pressure in different surfaces of the scaffold and better transportation of oxygen and growth factors as well. In gradient architecture scaffolds under dynamic conditions, there is a gradient in shear stress that causes various signaling in different positions of theses scaffold and facilitates multi-differentiation of the cells on the same scaffold.ConclusionThe results could be used as an instructor by the researchers to optimize the stem cell’s microenvironment in vitro, and finally better designs of scaffolds as well as cellular experiments may be achieved through such functional tissue engineering studies.

کلیدواژه ها:

Computational simulation ، Stem cells ، Bioreactor ، Bone scaffolds