Tissue Engineering, Part A vol:14 issue:5 pages:901-901
TERMIS-EU 2008 Annual Meeting location:Porto, Portugal date:22-26 June 2008
Fluid flow mediated mechanical stimuli inside the scaffold appear to be affecting the in vitro proliferation and osteogenic differentiation. This study focuses on the characterization of the flow through a regular titanium scaffold by means of experimental and numerical analysis.
Experiments were carried out in a perfusion bioreactor designed for live imaging through the transparent cover. Distilled water was seeded with micro particles and perfused at a flow rate of 0.018ml/min through the titanium scaffold (width 6mm, length 20mm, height 0.5 mm) with a regular structure consisting of 0.5 mm by 0.5 mm struts and 0.3 mm wide channels, that have an inclination of 45˚ to the main flow direction. Images were captured at 10 fps with a CCD (Charge Coupled Device) camera mounted on a stereomicroscope. For every two subsequent images a vector field of 24 by 24 grid points was calculated with an optical flow algorithm.
A computational fluid dynamic (CFD) model of the flow was developed to predict the velocity profile and the wall shear stress. The mesh, presented 1.845.916 tetrahedral elements with an average single side of 25 µm .
Both experimental measurements and CFD model show similar flow profile, with a velocity peak of 0.4 mm/s. The average wall shear stress was calculated by the model to be 3.4 mPa.
The coupling of experimental analysis and numerical model, giving the flow characteristics experienced in the scaffold, represent the basis to quantify the relation between the hydrodynamic environment and the growth modulation of bone TE-constructs.