Patterning adherent cells within microchannels by combination of electrochemical biolithography and dielectrophoresis

We report a method to create cell-adhesive regions and to position adherent cells on the newly created regions in sequence within a microfluidic channel. One of the microelectrodes fabricated at the channel wall was used for locally electrogenerating hypobromous acid that renders the opposite face of the channel protein-adsorptive. After the fibronectin was immobilized on the treated region, an ac voltage was applied to the microelectrodes array in the presence of suspended HeLa cells. Since a repulsive force of negative dielectrophoresis directs the cells toward the weakest region of the nonuniform electric field, the cells were positioned on the fibronectinpatterned region to allow the cell adhesion, even in the presence of fluid flow.