Permeability versus Design in TPMS Scaffolds.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Computational Mechanics

Background:

• Scaffolds are crucial for bone tissue engineering, providing structural support for cell growth and new tissue formation.
• Triply periodic minimal surface (TPMS) scaffolds are investigated for their potential in bone regeneration.
• Understanding scaffold architecture's influence on fluid dynamics is vital for optimizing cell behavior and tissue development.

Purpose of the Study:

• To evaluate how the porous architecture of different TPMS scaffolds affects macroscopic permeability.
• To combine numerical simulations and experimental testing to analyze fluid flow through scaffolds.
• To compare the performance of Schwartz D, Schwartz P, and Gyroid TPMS scaffolds.

Main Methods:

• Experimental production of TPMS scaffolds (Schwartz D, P, Gyroid) with 70% porosity using MultiJet 3D printing.
• Experimental measurement of scaffold permeability using Darcy's Law for fluid passage.
• Numerical simulation using finite element (FE) models in ABAQUS® to analyze fluid flow under compression and identify potential fluid trapping zones.

Main Results:

• Scaffold unit cell design significantly influenced permeability and fluid flow velocity, despite identical porosity.
• Gyroid scaffolds exhibited higher permeability compared to other designs.
• Schwartz P scaffolds demonstrated a lower probability of fluid trapping, while Schwartz D scaffolds showed the poorest performance in both permeability and fluid flow.

Conclusions:

• The choice of TPMS unit cell architecture is critical for optimizing fluid dynamics in bone tissue engineering scaffolds.
• Gyroid and Schwartz P scaffolds show promise for bone tissue engineering applications, with selection depending on specific requirements.
• Schwartz D scaffolds are less suitable for promoting bone cell differentiation due to unfavorable fluid flow characteristics.