Polymer Grippers as End-Effectors for Biological Sample Manipulation

Abstract

We report the development of completely releasable SU-8 based polymer microgripper and the manipulation of normal rat kidney (NRK) cells suspended in phosphate buffered saline (PBS) solution using a generic biological sample manipulator, which incorporates such a polymer microgripper as an end-effector. The electrically insulative polymer gripper consists of a thick (~50 μm), patterned high aspect ratio (~5:1) layer of SU-8 as the structural layer and a thin nickel layer as the electrothermal heating layer. The fabricated polymer gripper was completely released from the substrate and mounted onto a ceramic pad. The gripper was characterized in air and PBS, and the displacement at the tips was 12 μm for 0.5 V in air and for 2 V in PBS. The mounted gripper was assembled as end-effector onto a biological nano-manipulator (L200, Zyvex Corporation, Richardson, TX). Pick-and-place of a single cell from a cluster of suspended cells in aqueous medium has been demonstrated using this set-up.