Computational Modeling of the Fluid Mechanical Environment of Regular and Irregular Scaffolds

Direct perfusion of three-dimensional cell-seeded biological scaffolds is known to enhance osteogenesis, which can be partly attributed to mechanical stimuli affecting cell proliferation and differentiation in the process of bone tissue regeneration. This study aimed to compare the hydrodynamic environment, including the distributions of fluid flow velocity, wall shear stress and pressure in pores filled with liquid, designed scaffold (DS), porous and biodegradable β-TCP (β-tricalcium phosphate) based on freeze-drying scaffold (FS) and dog's femora scaffold (NS). Gravity condition, inlet velocities of 1, 10, 100 and 1000, μm/s and medium viscosities of 1.003, 1.45 and 2.1, mPas were applied as the initial conditions. With an inlet fluid velocity of 100 m/s and a viscosity of 1.45 (10^-3, Pas, the simulation results of maximal and average wall shear stress were 15.675, mPas and 3.223, mPas for DS, 67.126, mPas and 5.949, mPas for FS, and 20.190, mPas and 1.629, mPas for NS. Variations of inlet fluid velocity and fluid viscosity produced corresponding proportional changes in fluid flow velocity, wall shear stress and pressure. DS and FS were evaluated in terms of simulation results and microstructure using NS as a reference standard. This methodology allows a greater insight into the complex concept of tissue engineering and will likely help in understanding and eventually improving the fluid-mechanical aspects.