The effect to flow rate characteristic on biodegradation of bone scaffold

Abstract

This paper proposes an improved modeling approach for bone scaffolds biodegradation. In this study, the numerical analysis procedure and computer-based simulation were performed for the bone scaffolds with varying porosities in determining the wall shear stresses and the permeabilities along with their influences on the scaffolds biodegradation process while the bio-fluids flow through within followed with the change in the flow rates. Based on the experimental study by immersion testing from 0 to 72 hours of the time period, the specimens with different morphologies of the commercial bone scaffolds were collected into three groups samples of 30%, 41%, and 55% porosities. As the representative of the cancellous bone morphology, the morphological degradation was observed by using 3-D CAD scaffold models based on microcomputed tomography images. By applying the boundary conditions to the computational fluid dynamics (CFD) and the fluid-structure interaction (FSI) models, the wall shear stresses within the scaffolds due to fluid flow rates variation had been simulated and determined before and after degradation. The increase of fluid flow rates tends to raise the pressure drop for scaffold models with porosities lower than 50% before degradation. As the porosities increases, the pressure drop decreases with an increase in permeability within the scaffold. The flow rates have significant effects on scaffolds with higher pressure drops by introducing the wall shear stresses with the highest values and lower permeability. These findings indicate the importance of using accurate computational models to estimate shear stress and determine experimental conditions in perfusion bioreactors for tissue engineering more accurate results will be achieved to indicate the natural distributions of fluid flow velocity, wall shear stress, and pressure.

The Effect of Morphology on the Biodegradation Behavior of Porous Magnesium Bone Scaffold

“…The bone scaffold with high permeability will be better in the regeneration process [7]. In this present study, the permeability was lower than the previous work of [20]. Figure 8 showed that specimen C (55% of porosity) was the highest permeability compare to the specimen A (30% of porosity) and B (41% of porosity).…”

“…The cross-section with a higher exposed surface area generated lower shear stress compared to the low exposed surface area. From the previous work conducted by [20,21] , the shear stress obtained was 0.12 x 10 -5 Pa -5.74 x 10 -5 Pa. In this study, the value of shear stress obtained is higher than the value of the shear stress of the previous study, this can occur due to different boundary conditions and method of analysis.…”

“…The 3D model before degradation was generated using SolidWorks 2014 software which is a cuboid shape with measuring 5 x 5 x 3 mm and the pore size is 0.8 mm , 0 (2018) E3S Web of Conferences https://doi.org/10.1051/e3sconf /201868010 68 10 1 st SRICOENV 2018 20 20 as shown in Figure 1. For the 3D model after degradation was taken based on the previous study by [20] based on a 72 hour immersion period with variations of models A, B, and C which can be seen in Figure 2. Table 1.…”

“…The computer simulation using CFD analysis also conducted by al. [20] to investigate shear stress on the bone scaffold.…”

“…In this study, the value of shear stress obtained is higher than the value of the shear stress of the previous study, this can occur due to different boundary conditions and method of analysis. [20,21] conducted the simulation in their study using CFD method and the boundary condition of the bone scaffold was not integrated with the bone strain. , 0 (2018) E3S Web of Conferences https://doi.org/10.1051/e3sconf /201868010 68 10 1 st SRICOENV 2018 20 20 Fig.…”