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Effect of matrix stiffness and adhesion ligand density on chondrogenic differentiation of mesenchymal stem cells.

Adhesion ligands and mechanical properties of extracellular matrix (ECM) plays significant roles in directing mesenchymal stem cells (MSCs) behaviors, but how they affect chondrogenic differentiation of MSCs have rarely been studied. In this study, we investigated the effects of matrix stiffness and adhesion ligand density on proliferation and chondrogenic differentiation of MSCs by using UV crosslinked hydrogels comprised with methacrylated gelatin (GelMA) and poly (ethylene glycol) diacrylate (PEGDA) under different weight ratio. The PEGDA/GelMA hydrogels were fabricated by adjusting the weight ratio of PEGDA and GelMA with low or high adhesion ligand density (0.05% and 0.5% GelMA respectively) and independent tunable stiffness (1.6, 6 and 25 kPa separately for hydrogels with 5%, 10% and 15% PEGDA). MSCs presented differential behaviors to ECM by adjusting its adhesion ligand density and stiffness. Cell proliferation and chondrogenic differentiation could be enhanced with the improvement of adhesives properties and stiffness, evidenced by cell viability assay, hematoxylin-eos instaining, Safranin O staining, immunohistochemistry (collagen types II, Col2a1) as well as the chondrogenic genes expression of Col2a1, Acan, and Sox9. This study may provide new strategies to design the scaffolds for cartilage tissue engineering. This article is protected by copyright. All rights reserved.