Effect of complex stimuli of shear stress and surface modification on proliferation and phenotype of chondrocyte

Articular cartilage has a poor ability to regenerate and repair itself. To restore cartilage defects, a method has been developed by culturing autologous chondrocytes to create a three dimensional tissue and then implanting the cultured tissue. However, articular chondrocytes easily leads to de-differentiation state and loses their ability to synthesize the functional cartilaginous matrixes during in vitro culture. Therefore, it is important to maintain their differentiated phenotype during the expansion culture of chondrocytes. The objective of this study is to develop a novel culturing methodology combined surface modification and mechanical stimuli on articular cartilage. To develop a surface-modified substrate, a SUS316L stainless plate was treated by Fine Particle Peening (FPP) technique using alumina particles. The chondrocytes were cultured on the modified stainless plate and stimulated by fluid-induced shear stress using a custom-made flow culture system. As a result, proliferation rate was increased and phenotypic-change of chondrocytes was also observed by culturing the chondrocytes on physically modified surface combined with fluid-induced shear stress. In addition, the synergetic effect on proliferation rate was observed by applying the surface modification and flow shear stress simultaneously.