Cellular Nutrition in Complex Three-Dimensional Scaffolds: A Comparison between Experiments and Computer Simulations

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cell Biology

Background:

• In vitro studies of 3D porous scaffolds for bone cell ingrowth face challenges with cell proliferation and differentiation in scaffold cores.
• Increasing scaffold volume exacerbates issues with nutrient and oxygen diffusion to inner cells.

Purpose of the Study:

• To develop and utilize an in vitro perfusion cell culture module for analyzing cells within the interior of 3D scaffolds.
• To investigate the impact of varying medium flow rates on cell viability inside scaffolds.

Main Methods:

• Development of an in vitro perfusion cell culture system to control medium flow rates through 3D scaffolds.
• Measurement of cell viability at different flow rates within the scaffold interior.
• Comparison of experimental results with finite element method (FEM) simulations predicting local oxygen concentration and shear stress.

Main Results:

• Local cell viability directly correlates with local oxygen concentration and shear stress within the scaffold.
• Higher perfusion flow rates improve oxygen supply to the core but increase shear stress on surface cells.
• Excessive shear stress at high flow rates negatively impacts cell vitality, particularly at the scaffold surface.

Conclusions:

• Both oxygen supply and shear stress are critical parameters influencing cell viability in 3D scaffolds.
• An optimal nutrient flow rate must balance adequate oxygenation with minimized detrimental shear stress for effective cell growth.
• This study provides a framework for optimizing perfusion parameters in tissue engineering scaffolds.