Continuous bone morphogenetic protein-2 gradients for concentration effect studies on C2C12 osteogenic fate.

Cells can respond to small changes in a varying concentration of exogenous signaling molecules. Here we propose the use of continuous surface chemical gradients for the in-depth study of dose-dependent effects on cells. A continuous surface gradient of bone morphogenetic protein-2 (BMP-2) is presented. The gradient covers a narrow range of surface densities (from 1.4 to 2.3 pmol/cm(2)) with a shallow slope (0.9 pmol/cm(3)). These characteristics represent a quasi-homogeneous surface concentration at the cell scale, which is crucial for cell screening studies. Cell fate evaluation at early stages of osteogenesis in C2C12 cells, indicates the potential of continuous gradients for in vitro screening applications. FROM THE CLINICAL EDITOR: The authors propose the use of surface-applied continuous chemical gradients for in-depth study of dose-dependent effects on cells. The method is demonstrated using BMP-2 proteins on C2C12 cells as a model system.