We fabricated a microfluidic device for the entrapment of nonadherent cells. Solution exchange was easily performed by introducing the solution into the cell-trapping microchannel. Immunostaining and labeling of the cell membrane of THP-1 cells were demonstrated using this device, which does not require cumbersome repetition of centrifugation and resuspension steps. (C) 2013, The Society for Biotechnology, Japan. All rights reserved.