(638c) Perfusion Modulated Macromolecule Distribution for Enhanced Osteogenesis In Chitosan-Based Composite Scaffolds

Biomimetic scaffolds provide a multitude of chemical and structural cues that direct the differentiation of human mesenchymal stem cells, and are essential for influencing 3D construct development and functional outcome.  Perfusion flow has the capability to augment this potential by creating a dynamic and physiologically relevant growth environment that has been shown to enhance the osteogenic potential of hMSCs.  A wide range of bioreactor systems have been used to obtain these results with the most common being spinner flasks, rotating wall vessels, and perfusion systems.  Of these, only the direct perfusion bioreactor systems perfuse media throughout the scaffold while the others are limited to surface flow.  These flow variations could significantly bias the macromolecule distribution within the 3D constructs we therefore aim to study the ability of perfusion flow pattern to modulate the microenvironment and impact the differentiation potential of hydroxyapatite-chitosan-gelatin (HCG) constructs.  The HCG scaffolds were housed in an in-house modular perfusion bioreactor system that allows hMSCs to be dynamically seeded using the same inoculm and then subsequently cultured under different flow conditions (Zhao and Ma 2005, Zhao et al., 2009).  The media flow pattern was found to profoundly impact macromolecule distribution within the scaffold and to enhance cellular spatial distribution, hMSC proliferation and osteogenic differentiation potential as assessed by alkaline phosphatase, alizarin red, osteopontin, osteocalcin, and BMP-2 protein expression, and microCT bone volume analysis (Sellgren and Ma 2011).  Our results show that transverse perfusion flow significantly influences the extracellular matrix (ECM) microenvironment, over that of parallel flow that in turn impact hMSC proliferation and osteogenic differentiation.  The results highlight the potential for combining biomimetic HCG scaffolds with the perfusion bioreactor system as a streamlined fabrication process for bone construct development from hMSCs.

References:

Sellgren K, and Ma T. 2011, Perfusion Conditioning of Hydroxyapatite-Chitosan-Gelatin Scaffolds for Bone Tissue Regeneration from Human Mesenchymal Stem Cells, J Tissue Eng Regen Med, DOI: 10.1002/term.396

Zhao F, and Ma T. 2005, Perfusion Bioreactor System for Human Mesenchymal Stem Cell Tissue Engineering: Dynamic Cell Seeding and Construct Development, Biotechnol Bioeng, 91: 482-493

Zhao F, Grayson W L, Ma T, Irsigler A. 2009, Perfusion Affects the Tissue Development Patterns of Human Mesenchymal Stem Cells in 3D scaffolds, J Cell Physiol, 219: 421-429