Computational Methods in the Modeling of Scaffolds for Tissue Engineering - Computational Modeling in Tissue Engineering - page 112

Fig. 6 Velocity profiles represented in a cross section under fluid flow perfusion (v = 100 lm/s).
a Irregular scaffold morphology fabricated with PLA-G5 (poly-lactide acid and glass), model
obtained from micro-CT (modified from Milan et al. [ 13 ]. b Representative volume element
obtained from CAD of rapid prototyping scaffold. Gyroid shape with 70% of porosity (top),
hexagonal prism with 70% of porosity (down) (modified from Olivares et al. [ 5 ])
RP can be an excellent fabrication technique to control the fluid stimuli within
scaffolds. From the study developed by Olivares et al. [ 5 ], two different scaffold
morphologies were selected (Fig. 6 b). A gyroid structure was compared with a
hexagonal straight prism. Pore interconnections of the hexagonal prism limited the
accessibility of the fluid to some areas inside the scaffold. With an inlet velocity of
100 lm/s, the fluid flow distribution for the gyroid structure was in the range
of 220-450 lm/s while for the hexagonal prism structure it was in the range of
220-300 lm/s.
4.2 Cell Seeding Simulation Using CFD Models
Cell seeding is a critical step in tissue engineering since it precedes the further
steps for the in vitro and in vivo culture. In tissue engineering, the optimization of
cell seeding and the comparison between different studies are problematic because
cell seeding depends highly on the structure of the scaffolds, such as porosity,
tortuosity, pore size and pore shape, the number of cells in suspension, etc.
Recently, a system to control cell seeding through perfusion was proposed by
combining a CFD study of a rapid prototyping porous scaffold with the perfusion
fluid flow experimentation [ 12 ]. Gyroid pore design was used for the scaffold
stereolithographic fabrication. The values of pore size distribution in an isotropic