Cell manipulation system based on a silicon micro force sensor with self-calibration from backside

In this work a system for cell manipulation is presented. A two axis stage was arranged on an inverted microscope to place cells in focus. Cell manipulation can thereby be observed while the system automatically runs force controlled measurements. A high precision linear motor moves a silicon force sensor, which has been equipped with a stimulation tool e.g. a micro capillary for cell injection. The sensor is made of silicon and consists of a membrane with a boss structure, which enables measurements as low as 120 μN. For the first tests on the sensor, an injection capillary is mounted on the topside, while the backside is fixed to a printed circuit board (PCB) which has an integrated connection for the air pressure. An air pressure was applied under the membrane because the glass capillaries with outer diameters of at least 1 μm do not allow calibration via other force sensors. This setup allows a unique self-calibration of the mounted sensor system, before the measurements of the occurred forces on the cells during the penetration of the capillary.