Characterisation of the deflection of thin perforated SiN membranes of micro-hole array chips used for the cell selection

An automated and reliable isolation of single cells is increasingly important for applications in the rapidly growing life science sector. Traditional methods, like limited dilution or cell-seeding in semi-solid media, are time-consuming, significantly limited by the number of clones that can be feasibly screened and not suitable for reliable generation of monoclonal cell lines. To enable a reliable isolation of single cell out of a high number of cells, a micro-hole array based fluidic system has been developed. Here single cells are positioned by using a suction pressure on the holes of a nitride membrane. The entrapped cells can be optically analysed and picked by a capillary system mounted on a micromanipulator. This picking process is working with small distances or contact between the capillary tip and the membrane of the micro-hole array chip. In this article the bending of the silicon nitride membrane is analysed in dependence of the applied suction pressure in order to know the resulting deflection offset (z-axis offset) at any position of the membrane. This enables a more reliable control of the picking procedure.