Supporting Information Three - dimensional heterogeneous assembly of coded microgels using an untethered mobile micro - gripper

Gripping characterization and analysis To achieve the capability of picking-and-placing and assembling hydrogels in 3D, the grippers were designed to have proper beam deflecting ability to be able to pick, transport and release a hydrogel of a given size and shape. The gap distance between two gripping magnets of a gripper was designed to be slightly smaller than the hydrogel to be assembled. When the gripper was holding a hydrogel, the final gap distance between the gripping magnets or the total deflection of gripper beams were fixed as constants depending on the size of the hydrogel. The total deflection of one thin beam is a summation of two different deflections, the deflection δtotal by the magnetic torque and the deflection by the reactive normal surface of the hydrogel δB T δS N