Experimental measurements and CFD modelling of hydroxyapatite scaffolds in perfusion bioreactors for bone regeneration

Abstract

In the field of bone tissue engineering, particular interest is devoted to the development of three-dimensional cultures to study bone cell proliferation under conditions similar to in vivo ones, e.g. by artificially producing mechanical stresses promoting a biological response (mechanotransduction). Of particular relevance in this context are the effects generated by the flow shear stress, which governs the nutrients delivery rate to the growing cells and which can be controlled in perfusion reactors. However, the introduction of three-dimensional scaffolds complicates the direct measurement of the generated shear stress on the adhered cells inside the matrix, thus jeopardising the potential of using multi-dimensional matrices. In this study, an anisotropic hydroxyapatite-based set of scaffolds is considered as a three-dimensional biomimetic support for bone cells deposition and growth. Measurements of sample-specific flow resistance are carried out using a perfusion system, accompanied by a visual characterization of the material structure. From the obtained results, a subset of three samples is reproduced using 3D-CFD techniques and the models are validated by virtually replicating the flow resistance measurement. Once a good agreement is found, the analysis of flow-induced shear stress on the inner B-HA structure is carried out based on simulation results. Finally, a statistical analysis leads to a simplified expression to correlate the flow resistance with the entity and extensions of wall shear stress inside the scaffold. The study applies CFD to overcome the limitations of experiments, allowing for an advancement in multi-dimensional cell cultures by elucidating the flow conditions in three-dimensional reactors.

Computational Modelling and Simulation of Scaffolds for Bone Tissue Engineering

“…In BTE, bioreactors are employed to grow functional tissues from MSCs in controlled in vitro conditions. This process provides a continuous supply of nutrients and the removal of waste products prior to in vivo implantation at bone defect sites [135,136]. Implementing a mathematical model of the process in a CFD simulation involves four key steps: designing the geometries of scaffolds and complimentary bioreactors, selecting the appropriate flow equations, and determining the boundary and initial conditions (Figure 13) [137,138].…”

Bamboo-Inspired Porous Scaffolds for Advanced Orthopedic Implants: Design, Mechanical Properties, and Fluid Characteristics

“…24,25 To address this, computational fluid dynamics (CFD) analysis, a simulation technique, is employed to visualize fluid properties within the scaffold. 26,27 The evolution of additive manufacturing (AM) has revolutionized orthopedic implant production. 28 In comparison to conventional manufacturing techniques, AM presents advantages in personalized customization, the ability to handle intricate geometries and design optimization 29 while also reducing production time and costs.…”

“…To meet these challenges, we propose the development of bionic porous scaffolds specifically designed for orthopedics through 3D bionic modeling of vascular bundle structures. Porous structures, characterized by interconnected networks of pores, offer a promising alternative to traditional solid metal implants, overcoming limitations and enhancing biological integration, nutrient diffusion, and mechanical support. , Notably, the fluid flow within porous implants plays a critical role in delivering oxygen and nutrients to cells and removing waste products. , To address this, computational fluid dynamics (CFD) analysis, a simulation technique, is employed to visualize fluid properties within the scaffold. , …”