Design and experimental testing of an electro-thermal microgripper for cell manipulation

This paper presents the design, fabrication and experimental characterization of an electro-thermally actuated microgripper suitable for single-cell manipulation. The analysis of the mechanical properties of cells is of great interest both in medicine and biology because the study of the cellular mechanical behaviour and resistance is necessary in these fields. Microgrippers (Bio-MEMS) have an important role in the manipulation of biological tissues and cells. In recent works, the research group simulated the mechanical behavior of grippers and the different actuation strategies. Considering the dimensional specifications and targets imposed by actuation and biocompatibility, in this paper, a microgripper based on electro-thermal actuation is studied. Starting from previous numerical results, a novel SU8 structure is designed and realized according to the micro-fabrication constraints and then the structure is simulated using the finite element method (FEM)-based thermo-structural simulations in ANSYS. Therefore, the fabrication method and steps are presented and the gripper has been developed and tested. Finally, the tip displacements of the gripper, electro-thermally actuated in different operating conditions, are compared with those obtained by means of numerical FEM simulations. A good agreement is obtained between simulations and experimental results.