Spatially controlled functional group grafting of silk films to induce osteogenic and chondrogenic differentiation of human mesenchymal stem cells

For tissue engineering, fabrication of appropriate biomaterials, which not only support cellular attachment and proliferation but also direct lineage-specific differentiation of stem cells is crucial. It is widely reported in literature that biomaterial surface chemistry modulates human mesenchymal stem cell (hMSC) differentiation in a lineage dependent manner. In recent years, natural materials such as silk have been used for hMSC culture because of its superior mechanical strength, biocompatibility, and biodegradability. We report here a simple strategy for differentiating hMSCs into two different lineages on the same surface. We have grafted functional groups such as acrylic acid and phosphates to guide the differentiation of hMSCs into chondrocytes and osteocytes respectively. Unlike other strategies, our strategy does not require growth factors and other added signals in the media and is initiated due to the difference of functional groups present on the surface. We believe this study will foster the development of effective silk based tissue engineered constructs.