Precise patterning of photoactivatable glass coverslip for fluorescence observation of shape-controlled cells

The shape of cells is a key determinant of cellular fates and activities. In this study, we demonstrate a method for controlling the cellular shape on a chemically modified glass coverslip with micropatterned cell adhesiveness. The glass surface was chemically modified with an alkylsiloxane monolayer having a caged carboxyl group, where single-cell-sized hydrophilic islands with hydrophobic background were created by irradiating the substrate in contact with a photomask to produce the carboxyl group. Thus, the created surface hydrophilicity pattern was converted to a negative pattern of a protein-repellent amphiphilic polymer, Pluronic F108, according to its preferential adsorption to the hydrophobic surfaces. The following addition of a cell-adhesive protein, fibronectin, resulted in its selective adsorption to the irradiated regions. In this way, cell-adhesive islands were produced reproductively, and the cells formed a given shape on the islands. As examples of the cell-shape control, we seeded HeLa cells and NIH3T3 cells to an array of triangular spots, and fluorescently imaged the dynamic motions of cell protrusions extended from the periphery of the cells. The present method will not only be useful for studying the molecular mechanism of cell polarity formation, but also for studying other shape-related cellular events such as apoptosis, differentiation and migration.