The motion of microbeads in shear flow throgh a conical tube

Using confocal microscopy, we studied the individual motion of fluorescent platelet-sized latex beads suspended in glycerol-PBS solution, flowing through a narrow gap of 80 um width in a PDMS-conical channel with a round ball inside. The trajectories and the velocity profiles of beads were investigated in the gap region, in the absence or presence of red cells at hematocrit 1%. The presence of red cells enhanced the fluctuations of the beads velocities and often deflected their trajectories from the streamlines of the suspension fluid, especially near the channel wall.