A Virtual Test Bench to Study Transport Phenomena in 3D Porous Scaffolds Using Lattice Boltzmann Simulations

Abstract

In tissue engineering (TE), scaffolds are widely used to provide a suitable and native-like environment for cell growth, organization, and proliferation. Microstructure of TE scaffolds is fundamental to the cell attachment and in-depth penetration, in conjunction with biological factors as cell seeding and nutrients supply. In particular, several studies have established that an adequate transport of nutrient through the scaffold is fundamental for culturing cells [1]. Hence, the easiness at which fluids/species move through the scaffold and friction forces exherted from fluid motion, have a marked impact in TE processes [2]. Mass transport through scaffolds is a phenomenon that can be described at different scales, the molecular level (nanoscale), the single-pore dimension level (microscale) and the whole-sample level (macroscale). In this work we present a virtual test bench where realistic 3D models of porous TE scaffolds are reconstructed from micro-CT images and the transport phenomena through them is simulated in silico by applying the Lattice Boltzmann Method (LBM). The final aim is to create an effective in silico tool suitable to study and optimize transport phenomena of porous scaffolds. The application of the LBM is justified by its versatility in simulating flows in irregular porous media (i.e. simplicity of handling complex boundaries) and in providing insights into transport properties such as permeability [3–4] and physical quantities as the shear stress, which are barely achievable experimentally [2]. Here, the virtual tool is applied to evaluate the performance of three biomimetic bioactive glass/polymer composite porous scaffolds for bone tissue regeneration with well-known mechanical and chemical properties, but never characterized in terms of transport phenomena. The in silico results are macroscopically validated in terms of permeability (kC) by comparison with experimental permeability (kE) measurements obtained by means of a dedicated test bench, very recently proposed for the characterization of porous media [5].