Page 177 - IJB-9-3

International Journal of Bioprinting Flow performance of porous implants with different geometry

Figure 15. The proportion of wall shear stress distribution: (a) OT; (b) G; and (c) P.

two obvious distinct regions of cell differentiation in the comparing these three types of structures, because of
scaffold. Combined with Figure 9 and Figure 12, the flow more concentrated volume distribution, volume structures
velocity of fluid in contact with the wall surface changed had smaller specific surface areas, uneven distribution of
very little, which led to the concentrated distribution of the flow velocities and higher permeabilities, while surface
wall shear stress of P structure. On the contrary, the fluid structures had the highest tortuosities. These different
in contact with the wall surface in OT and G structures had physical performance characteristics would indirectly
greatly varied flow velocity, making these two structures affect the biological properties of scaffolds, which were of
have more diversified stress distribution. In other words, great significance to personalized clinical use. In addition,
the concentrated mass distribution in volume structure nowadays, porous implants could be easily printed by
would inevitably lead to the stable and concentrated additive manufacturing, which means that controlling the
wall shear stress distribution, while the diverse stress design of scaffolds to achieve ideal implants was entirely
distribution in line and surface structure was beneficial to possible. Therefore, the reliable results of this study could
cell differentiation. be used for reference in designing.
Overall, CFD method was widely used to evaluate Finally, there were also some limitations in this study.
fluid flow performance, which could reflect the biological First, only one shape was selected from each type of
performance of porous implant indirectly. CFD method is structure, which was not enough to meet various needs
a reliable, rapid and low-cost method for evaluating porous in practice. Besides, the differences of flow performance
implants compared to traditional cell culture and animal between line structures and surface structures were not
experiments, similar to finite element analysis (FEA) which obvious. In the future, more shapes from these three types
is used to evaluate the mechanical properties of the implant. of structure should be studied to reach more common
The validity of CFD method had also been extensively conclusions. Second, although CFD method could
demonstrated by previous studies [35-40] . Therefore, the replace traditional cell culture and animal experiments to
findings in this study were reliable. In general, this study some extent, it is still necessary to verify the correctness
confirmed that for line, surface and volume structures, the of simulation by conducting experiments. Besides, the
reduction of characteristic parameters resulted in higher implants printed through additive manufacturing might
porosities, which led to slower flow velocities, higher also have errors as compared to original designs. Therefore,
permeabilities and more appropriate wall shear stress; future research should focus on actual manufacturing and

Volume 9 Issue 3 (2023) 169 https://doi.org/10.18063/ijb.700