Dual Roles of Graphene Oxide in Chondrogenic Differentiation of Adult Stem Cells: Cell-Adhesion Substrate and Growth Factor-Delivery Carrier

Here, it is shown that graphene oxide (GO) can be utilized as both a cell-adhesion substrate and a growth factor protein-delivery carrier for the chondrogenic differentiation of adult stem cells. Conventionally, chondrogenic differentiation of stem cells is achieved by culturing cells in pellets and adding the protein transforming growth factor-beta 3 (TGF-beta 3), a chondrogenic factor, to the culture medium. However, pellets mainly provide cell-cell interaction and diffusional limitation of TGF-beta 3 may occur inside the pellet both of these factors may limit the chondrogenic differentiation of stem cells. In this study, GO sheets (size = 0.5-1 mu m) were utilized to adsorb fibronectin (FN, a cell-adhesion protein) and TGF-beta 3 and were then incorporated in pellets of human adipose-derived stem cells (hASCs). The hybrid pellets of hASC-GO enhanced the chondrogenic differentiation of hASCs by adding the cell-FN interaction and supplying TGF-beta 3 effectively. This method may provide a new platform for stem cell culture for regenerative medicine.