Investigating wall shear stress and the static pressure in bone scaffolds: a study of porosity and fluid flow dynamics.

Abstract

In bone tissue engineering, scaffolds are crucial as they provide a suitable structure for cell proliferation. Transporting Dulbecco's Modified Eagle Medium (DMEM) to the cells and regulating the scaffold's biocompatibility are both controlled by the dynamics of the fluid passing through the scaffold pores. Scaffold design selection and modeling are thus important in tissue engineering to achieve successful bone regeneration. This study aims to design and analyze three scaffold designs-Face-Centered Cubic (FCC), and two newly developed designs Octagonal Truss and a Square Pyramid with four porosity variations. The research aims to analyze the effect of design and porosity variation on pressure and wall shear stress, essential for analyzing scaffold biocompatibility in tissue engineering. Three scaffold designs with varying porosities with strut diameters ranging from 0.3  to 0.6 mm were modeled to analyze the behavior using BioMed Clear Resin. The fluid dynamics within these scaffolds were then examined using Computational Fluid Dynamics (CFD) to understand how different porosity levels affect fluid flow pressure and wall shear stress. The findings revealed variations in wall shear stress and their influence on cell proliferation. The maximum value of wall shear stress (WSS) is observed in the Square Pyramid model. The analysis shows that WSS at the inlet decreases as strut diameters increase or porosity percentages rise offering valuable insights for the development of effective scaffold designs. It can be concluded from the results that the Square Pyramid design has the highest value of WSS, thus increasing the chances of cell growth. From a biological perspective, the results of this work show promise for creating better scaffolds for tissue engineering.