Micro-Gripper: A new concept for a monolithic single-cell manipulation device

Single-cell analysis and manipulation methods are becoming increasingly important for fundamental research, as well as practical applications, such as in vitro fertilization (IVF) and pharmaceutical research and development. The need for adequate handling tools is reflected in a large number of publications discussing grippers, injection automation, or cell immobilization. Endeavors toward the improvement of existing devices focus on the continuous monitoring of multiple parameters, such as gripping force, constitution of the medium, or recording of video sequences, enabling the operator or the operating system to verify proper functioning of the method and the success of the operation. The approach described in this conceptual study unifies the steps of cell positioning, immobilization, tool alignment, manipulation, and analysis by integrating the necessary devices into a single monolithic tool based on a micromechanical gripper. The critical mechanical and fluidic aspects of the new design are investigated by analytical calculations and finite-element analysis to evaluate the feasibility of the micro-gripper. In doing so, local critical stresses inside the oocytes have been determined, allowing conclusions on the micro-gripper design. Furthermore, the monolithic micro fabrication route is described, and the first results of the process development for integrated injection and immobilization channels are presented. (C) 2015 Elsevier B.V. All rights reserved.