Scaffold mean pore size influences mesenchymal stem cell chondrogenic differentiation and matrix deposition

Recent investigations into micro-architecture of scaffolds has revealed that mean pore sizes are cell-type specific and influence cellular shape, differentiation, and extracellular matrix secretion. In this context, the overall goal of this study was to investigate whether scaffold mean pore sizes affect mesenchymal stem cell initial attachment, chondrogenic gene expression, and cartilage-like matrix deposition. Collagen-hyaluronic acid (CHyA) scaffolds, recently developed in our laboratory for in vitro chondrogenesis, were fabricated with three distinct mean pore sizes (94, 130, and 300 μm) by altering the freeze-drying technique used. It was evident that scaffolds with the largest mean pore sizes (300 μm) stimulated significantly higher cell proliferation, chondrogenic gene expression, cartilage-like matrix deposition, and resulting bulk compressive modulus after in vitro culture, relative to scaffolds with smaller mean pore sizes (94, 130 μm). Taken together, these findings demonstrate the importance of scaffold micro-architecture in the development of advanced tissue engineering strategies for articular cartilage defect repair.