Monolithically Fabricated Microgripper With Integrated Force Sensor for Manipulating Microobjects and Biological Cells Aligned in an Ultrasonic Field

TLDR

The paper presents an electrostatic MEMS gripper that incorporates a capacitive force sensor. The gripper uses electrostatic actuation with a capacitive sensor providing high‑resolution force feedback, and a MEMS ultrasonic device aligns sub‑100‑µm particles in water so the gripper can pick them from a fixed position. Its force sensitivity exceeds that of other monolithically fabricated MEMS grippers by more than three orders of magnitude, and the system successfully manipulates HeLa cells, proving its utility for biological research.

Abstract

This paper reports an electrostatic microelectromechanical systems (MEMS) gripper with an integrated capacitive force sensor. The sensitivity is more than three orders of magnitude higher than other monolithically fabricated MEMS grippers with force feedback. This force sensing resolution provides feedback in the range of the forces that dominate the micromanipulation process. A MEMS ultrasonic device is described for aligning microobjects suspended in water using ultrasonic fields. The alignment of the particles is of a sufficient accuracy that the microgripper must only return to a fixed position in order to pick up particles less than 100 mum in diameter. The concept is also demonstrated with HeLa cells, thus providing a useful tool in biological research and cell assays