Challenges in computational fluid dynamics applications for bone tissue engineering

Abstract

Bone injuries or defects that require invasive surgical treatment are a serious clinical issue, particularly when it comes to treatment success and effectiveness. Accordingly, bone tissue engineering (BTE) has been researching the use of computational fluid dynamics (CFD) analysis tools to assist in designing optimal scaffolds that better promote bone growth and repair. This paper aims to offer a comprehensive review of recent studies that use CFD analysis in BTE. The mechanical and fluidic properties of a given scaffold are coupled to each other via the scaffold architecture, meaning an optimization of one may negatively affect the other. For example, designs that improve scaffold permeability normally result in a decreased average wall shear stress. Linked with these findings, it appears there are very few studies in this area that state a specific application for their scaffolds and those that do are focused on in vitro bioreactor environments. Finally, this review also demonstrates a scarcity of studies that combine CFD with optimization methods to improve scaffold design. This highlights an important direction of research for the development of the next generation of BTE scaffolds.

Design considerations of benchtop fluid flow bioreactors for bio-engineered tissue equivalents in vitro

“…While the use of CFD allows a bioreactor to be optimised for specific tissues, in practice this is not always performed as effectively as it could be. One recent review, for example, highlights that many bioreactors for bone tissue engineering are designed for generic bone tissue engineering, rather than for use modelling specific bones, which could therefore limit their utility due to the wide variability of conditions in different locations [182] .…”

Efficient calculation of fluid-induced wall shear stress within tissue engineering scaffolds by an empirical model

“…In tissue engineering (TE) experiments in vitro, cells are usually cultured in a 3D environment, for which porous scaffolds are used for housing the cells [2]. Previous studies have found that scaffold porous geometric characteristics, such as porosity, pore size and pore shape, can influence the internal microfluidic environment, including the WSS on cells within scaffolds [3,4]. Also, according to Refs.…”

“…To quantify the WSS within scaffold, usually a numerical approach (e.g., based on computational fluid dynamics -CFD model) is needed due to the infeasibility of direct measurement of fluid-induced WSS [4,6]. These CFD models are based on the scaffold geometries from either computer-aided design (CAD) [5,7] or micro-computed tomography (microCT) images [7,8].…”

Wall Shear Stress Analysis and Optimization in Tissue Engineering TPMS Scaffolds

“…Therefore, computational simulations are normally implemented to reduce the time and cost associated with conceptualizing a new scaffold. For BTE, computational fluid dynamics (CFD) analysis is essential in understanding how changes to a scaffold’s design influence its fluidic properties (such as the WSS) and the underlying cellular processes [ 12 , 13 , 14 ].…”

“…This process repeats itself iteratively until a new structure satisfies the objective function. However, in BTE, optimization methods have rarely focused on the fluidic properties of the scaffold [ 14 , 15 , 16 ], instead only consider the scaffold’s mechanical properties (such as their Young’s modulus [ 17 ]; compressive strength [ 18 ] and octahedral shear strain [ 19 , 20 , 21 ]).…”