Bilayer microfluidic chip for diffusion-controlled activation of yeast species

A bilayer microfluidic chip is used, in which multiple laminar streams are generated to define local microenvironments. The bilayer architecture of the microchip separates cell handling and positioning from cell activation by soluble chemicals. Cell activation is diffusion controlled through a porous membrane. By employing time-lapse fluorescence microscopy, gene expression of the enhanced green fluorescent protein (eGFP) in Saccharomyces cerevisiae is studied under various conditions. We demonstrate that the yeast cells remain viable in the microchip for at least 17 h, and that gene expression can be initiated by the supply of the inducer galactose at a spatial precision of a few micrometers.