Permea-Design: An Innovative Tool for Generating Triply Periodic Minimal Surface Scaffolds with Tailored Permeability

The permeability of a porous material is the measure of the ability of fluids to pass through it. The ability to control permeability is valued by tissue engineers who manufacture tissue engineering scaffolds that house cells/tissue and facilitate tissue growth. Therefore, a scaffold design software in which permeability can be entered as a variable in determining the structure and strut topology would be a desirable tool for tissue engineering researchers. The ability to factor permeability directly into the design of scaffolds facilitates more effective bone tissue engineering by enabling optimal nutrient transport and waste removal at regeneration sites. Additionally, having the ability to control the mechanical environment by indicating a region of acceptable porosities for in vitro cell culturing is desirable. This desirability is a result of porosity being a major determining factor in permeability, where increasing porosity will generally mean a higher permeability. Thus, having an upper bound on porosity means that higher-permeability structures can be determined whilst maintaining high values of mechanical strength. In this software, a method is discussed for modifying the Kozeny–Carman equation by incorporating level-set equations for different triply periodic minimal surface (TPMS) structures. Topology analysis is computed on six different TPMS structures in the toolbox, and a relationship between a topological constant and permeability is derived through the Kozeny–Carman equation. This relationship allows for an input of permeability as a factor in the determination of pore size, porosity, and scaffold structure. This novel method allows for scaffold design based on a tailored permeability to assist successful tissue engineering.