Effect of RGDS-expressing fibroin dose on initial adhesive force of a single chondrocyte

Initial chondrocyte-material interactions are important for cell behaviors such as proliferation, phenotypic expression and matrix synthesis. Previously, we showed that chondrocytes cultured in/on silk fibroin scaffolds proliferate without dedifferentiating into fibroblast-like cells and that RGDS sequences genetically interfused in the fibroin light chain protein enhance cartilage tissue formation. In the present study, the adhesive force of chondrocytes was measured on fibroin substrates containing RGDS-expressing fibroin molecules produced by transgenic silkworms at the different densities of 0, 0.6, 1.5 and 3.0 mol%. The degree of chondrocyte attachment to fibroin substrates increased with the number of RGDS-expressing fibroin molecules. Moreover, the adhesive force per unit spreading area of a single cultured chondrocyte exhibited a peak that was higher with increased RGDS concentrations. The results of this study indicate that the RGDS sequences genetically interfused in the fibroin light chain protein exert effects on chondrocytes' adhesive behavior and can enhance cartilage tissue organization.