“…Once the bead is trapped in the potential well of the DW, the DW can be used to manipulate individual beads. Indeed, bead transport has been realized by either stepping a bead from one DW trap site to the next 19,[21][22][23][24]27 or moving it continuously with a propagating DW 20,22,25,26 . Continuous transport is limited, however, by the maximum interaction force, or binding force , between the bead and DW, which must overcome the hydrodynamic drag force on the bead as it is pulled through the host fluid 20 .…”