A microwell device for measurement of membrane transport of adherent cells

We developed the microwell device for measurement of membrane transport of single adherent cells. As the cells in a population (e.g., tumor) is inevitably heterogeneous, a technique to measure the transport activities at a single-cell level is needed. When adherent cells were cultured on the microwells with ~10 μm diameter, they spread over the opening to form the closed picoliter space. Thus, molecules exported from cells accumulate in such a space and be detected by fluorescence imaging. In this report, we show that, by employing horizontal microwell design, materials exported from the cell membrane can be visualized without overlapping with the cell, increasing the S/N ratio of the fluorescence signal. Efflux of the cancer drug transported by the multidrug resistance protein was detected.