Attachment of cells to islands presenting gradients of adhesion ligands

This paper reports a strategy that uses microfluidic networks to pattern self-assembled monolayers with gradient microislands for the attachment of individual cells. A microfluidic network is first used to pattern a monolayer into square regions that present maleimide groups and then used to flow a solution having a gradient of the cell adhesion peptide Arg-Gly-Asp over the substrate. In this way, the surface is patterned with microislands approximately 33 x 33 micrometers in size and each having a defined gradient of immobilized cell adhesion ligand. B16F10 cells were allowed to attach to the patterned islands and were found to display a nonuniform distribution of cytoskeletal structures in response to the gradient of adhesion ligand. This work is significant because it permits studies of the influence of a nonuniform microenvironment on the polarization, differentiation, and signaling of adherent cells.