Microrobotics for Molecular Biology: Manipulating Deformable Objects at the Microscale

Abstract

Recent advances in molecular biology such as cloning demonstrate that increasingly complex micromanipulation strategies for manipulating individual biological cells are required. From a robotics standpoint, the manipulation of biological cells, sometimes referred to as biomanipulation, presents several interesting research issues that extend well beyond cell manipulation. Biological cells are highly deformable objects, and the material properties of these objects are not well quantified, so developing strategies for manipulating deformable objects must be addressed. Most biological cells are between 1μm and 100μm in diameter, depending on the cell type, so micromanipulation issues must be explored, including the appropriate use of high resolution, low depth-of-field vision feedback and very low magnitude multi-axis force feedback. By pursuing robotic manipulation of biological cells, many interesting robotics research avenues in micromanipulation, deformable object handling, multi-sensor integration, and force and vision feedback assimilation must be explored. This paper explores the visual tracking of biological cells using physics-based models and the measurement of applied force fields using a new cell deformation model with visual feedback. A multi-axis MEMS-based force sensor is used to determine applied forces and develop models of cell deformation. Robust tracking of cell deformation is shown and real-time determination of applied force fields is demonstrated. In addition, the system developed has been used to quantitate for the first time a phenomenon known as “zona hardening” during mouse oocyte fertilization.