Micronewton force-controlled manipulation of biomaterials using a monolithic MEMS microgripper with two-axis force feedback

This paper presents the first demonstration of force-controlled micrograsping at the microNewton force level. The system manipulates highly deformable biomaterials (hydrogel microcapsules and biological cells) in an aqueous environment using a MEMS-based microgripper with integrated force feedback along two axes. The microgripper integrates an electrothermal V-beam microactuator and two capacitive force sensors, one for contact detection (force resolution: 38.5 nN) and the other for gripping force measurements (force resolution: 19.9 nN). The MEMS-based microgripper and the force control system experimentally demonstrate the capability of rapid contact detection and reliable force-controlled micrograsping to accommodate variations in sizes and mechanical properties of objects with a high reproducibility. Cell viability testing validated that the temperature at gripping arm tips does not exceed 50degC.