Effects of bio-mimic collagen II-g-hyaluronic acid copolymers on chondrocyte maintenance

Extracellular matrix has an important part of the role in tissue engineering and regenerative medicine, so it is necessary to understand the various interactions between cells and extracellular matrix. Type II collagen and hyaluronic acid are the major structural components of the extracellular matrix of articular cartilage, and they are involved in fibril formation, entanglement and binding. The aim of this study was to prepare type II collagen fibrils with surface grafted with hyaluronic acid modified at the reducing end. The topographic pattern of type II collagen fibrils showed a significant change after the surface coupling of hyaluronic acid according to atomic force microscopy scanning. The presence of hyaluronic acid on the type II collagen fibrillar surface was confirmed by the specific binding of nanogold labelled with lectin. No significant increase in cell proliferation was detected by a WST-1 assay. According to histochemical examination, the maintenance of the round shape of chondrocytes and increased glycosaminoglycan secretion revealed that these cell pellets with Col II- g-hyaluronic acid molecules contained un-dedifferentiated chondrocytes in vitro. In the mixture with the 220-kDa Col II- g-hyaluronic acid copolymer, the expression of type II collagen and aggrecan genes in chondrocytes increased as demonstrated by real-time polymerase chain reaction analysis. Experimental results show that the amount of hyaluronic acid added during culturing of chondrocytes can maintain the functionality of chondrocytes and thus allow for increased cell proliferation that is suitable for tissue repair of human cartilage.