Viability, adhesion and differentiated phenotype of articular chondrocytes on degradable polymers and electro-spun structures thereof


Degradable polymers are essential to enable biomaterial-based regenerative therapies, particularly, in articular cartilage defect healing, which remains a major clinical challenge. The aim of this study was to investigate the effect of two degradable polymers (as a film or scaffold) on primary articular chondrocytes vitality, adherence, differentiated phenotype and morphology. Films and electro-spun scaffolds were prepared from degradable poly(ether)ester urethane (PDC), which was synthesized via co-condensation of poly(p-dioxanone)diol and poly(ε-caprolactone)diol with an aliphatic diisocyanate and poly(p-dioxanone) (PPDO). The thermal and mechanical properties and the surface roughness of the films and scaffolds were examined by differential scanning calorimetry, dynamic mechanical thermal analysis, tensile tests and optical profilometry. Primary porcine articular chondrocytes were seeded on the polymers and analysed for viability, ultrastructure (scanning electron microscopy) and immunolabelled for type II collagen. All films and scaffolds exhibited a low endotoxin load < 0.06 EU/ml and only moderate cytotoxic effects when tested with L929 cells. The results of the seeding experiments revealed that survival and adhesion of chondrocytes depended strongly on seeding density. Vital chondrocytes could be detected on both PPDO and PDC films and scaffolds. They produced the cartilage-specific protein type II collagen indicating differentiated functions. However, they exhibited a mixed morphology on the films and a more flattened cell shape on the scaffolds. The cell/biomaterial interaction in the PPDO scaffolds or films was more intense compared to that in PDC topologies.
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