Surface chemistry, substrate, and topography guide the behavior of human articular chondrocytes cultured in vitro

Understanding the behavior of chondrocytes in contact with artificial culture surfaces is becoming increasingly important in attaining appropriate ex vivo culture conditions of chondrocytes in cartilage regeneration. Chondrocyte transplantation‐based cartilage repair requires efficiently expanded chondrocytes and the culture surface plays an important role in guiding the behavior of the cell. Micro‐ and nanoengineered surfaces make it possible to modulate cell behavior. We hypothesized that the combined influence of topography, substrate, and surface chemistry may affect the chondrocyte culturing in terms of proliferation and phenotypic means. Human chondrocytes were cultured on polystyrene fabricated microstructures, flat polydimethylsiloxane (PDMS) or polystyrene treated with fibronectin or oxygen plasma, and cultured for 1, 4, 7, and 10 days. The behavior of chondrocytes was evaluated by proliferation, viability, chondrogenic gene expression, and cell morphology. Contrary to our hypothesis, microstructures in polystyrene did not significantly influence the behavior of chondrocytes neither under normoxic‐ nor hypoxic conditions. However, changes in the substrate stiffness and surface chemistry were found to influence cell viability, gene expression and morphology of human chondrocytes. Oxygen plasma treatment was the most important parameter followed by the softer substrate type PDMS. The findings indicate the culture of human chondrocytes on softer substratum and surface activation by oxygen plasma may prevent dedifferentiation and may improve chondrocyte transplantation‐based cartilage repair