Effect of 3D-microstructure of bioabsorbable PGA:TMC scaffolds on the growth of chondrogenic cells

Various biomaterial scaffolds have been investigated for cartilage tissue engineering, although little attention has been paid to the effect of scaffold microstructure on tissue growth. Non-woven, fibrous, bioabsorbable scaffolds constructed from a copolymer of glycolide and trimethylene carbonate with varying levels of porosity and pore size were seeded with mesenchymal stroma cells with a chondrogenic lineage. Scaffolds and media were evaluated for both cell and extracellular matrix organization and content after up to 28 days of culture in a spinner flask. Analysis of DNA and glycosaminoglycan contents showed that the most porous of the three scaffold types, with a porosity of 81% and a porometry determined mean flow pore diameter of 54 microm, supported the most rapid proliferation of cells and accumulation of extracellular matrix. Analysis of the high porosity scaffold system, using Western Blot and immunohistochemistry confirmed the presence of collagen type II and absence of collagen type I, and demonstrated cells with a chondrocyte morphology with aggrecan and collagen II accumulation attached to the scaffolds. It was concluded that the 3D-microstructural characteristics of the scaffold (interconnecting porosity and pore size) play an important role in proliferation and phenotype of chondrogenic cells and accumulation of extracellular matrix molecules.