Measuring the mechanical behaviour of human oocytes with a very simple SU-8 micro-tool

The elasticity of human oocytes has been estimated by means of a very simple SU-8 microsystem. The device consists of a double SU-8 layer spin coated on a silicon wafer. A micro-beam is patterned by standard photolithography. The silicon wafer is back etched using deep reactive ion etching (DRIE) in order to release the micro-beam. Because the SU-8 resin exhibits a very low Young modulus, beams with stiffnesses of 12 N/m have been easily fabricated. Although the stiffness is not as low as that of Atomic Force Microscopes cantilevers, it was possible to estimate the "deformation-load" characteristics of a few oocytes. A "flattening parameter" of the oocytes is proposed as a function of the applied load and experimental values range from 0.86 microm(2)/Pa to 3.4 microm(2)/Pa for the oocytes under test. Note that this paper belongs to the very few communications concerning the mechanical behaviour of human oocytes.