Control of stem cell fate by engineering their micro and nanoenvironment

Figure 3 Effect of substrate stiffness on the differentiation of stem cells. A: The neuronal cytoskeletal marker β3 tubulin is expressed in branches (arrows) of initially naive mesenchymal stem cells (MSCs) (> 75%) and only on the soft, neurogenic matrices. The muscle transcription factor MyoD1 is upregulated and nuclear localised (arrow) on myogenic matrices and osteoblast transcription factor CBF-α1 (arrow) is expressed only on stiff, osteogenic gels. Scale bar is 5 μm; B: The microarray profiles of MSCs cultured on 11 or 34 kPa matrices. The expression was normalised first to actin and then to expression of committed C2C12 myoblasts and hFOB osteoblasts; C: The highest fluorescent intensity of differentiation markers was observed at the substrate elasticity of the elastic modulus typical of each tissue type. Taken with permission from Engler AJ, Sen S, Sweeney HL, Discher DE. Matrix elasticity directs stem cell lineage specification. Cell 2006; 126: 677-689.