Fig. 1. Experimental set-up and working principle of the robot-assisted acoustofluidic end effector (RAEE) device.

a The RAEE device is comprised of a glass capillary and piezo-electronic transducer connected to a five-axis robotic arm. The whole set-up was mounted on an inverted microscope using a capillary holder. The inset illustrates the overall experimental set-up. b An enlarged view of the RAEE device when submerged in liquid with a focus on streaming profiles, especially the out-of-plane streaming. c The acoustofluidic device generated two distinct flow profiles: (i) circular-flow fields along the shaft of the capillary, and (ii) frequency-dependent 3D streaming at the tip of the glass capillary. d We have applied the RAEE to execute pumping, selective trapping, and viscous mixing.