The Ismagilov and Mrksich groups at the University of Chicago MRSEC have recently established that a microfluidic system utilized in conjunction with surface immobilization chemistries can be used to pattern surfaces with well-defined gradients of adhesion molecules for the attachment of cells.
The image shows the patterned surface after placement in a suspension of B16F10 mouse melanoma cells and fixing and immunostaining with antibody against vinculin (found in the focal adhesion structures integrating the cytoskeleton with the extracellular matrix).
Each gradient microisland contained a nonuniform distribution of active ligands for cell-adhesion; the resulting nonuniform adhesion of the mouse melanoma cells is depicted. 
This general technique of preparing gradients of immobilized species with specific patterns is expected to be an important tool for understanding the influence of nonuniform microenvironments on cell function, including polarization and migration.
- “Attachment of Cells to Islands Presenting Gradients of Adhesion Ligands,” Rafe T. Petty, Hung Wing Li, Jane H. Maduram, Rustem Ismagilov, and Milan Mrksich, J. Am. Chem. Soc., 129, 8966-8967 (2007).
Work made possible by the NSF MRSEC award, DMR-0213745, to the University of Chicago.