Characterization of the Membrane Transport Assay System Using Microchamber Array

We have been developing a measurement system for membrane transport across a reconstituted planar lipid bilayer to examine the functions of transporter membrane proteins using a microchamber array (membrane microchamber system). In this system, an artificial planar lipid bilayer is pressed on the parylene microchamber array (typically 0.1~1 pL in volume) fabricated on a coverglass to enclose the volume. After membrane proteins are reconstituted in the bilayer, fluorescently labeled molecules transported across the bilayer are accumulated in microchambers, and detected by fluorescent imaging. The microchamber array is compatible with high-sensitive biological imaging techniques, such as a confocal microscopy and a total internal reflection fluorescence microscopy (TIRFM). Due to the tiny volume of microchambers, concentration of the transported molecules rapidly increases. In this study, the detection system was characterized in detail. With the aid of microchambers, the concentration reached to the detectable level with as small as 102~103 fluorescent molecules