Nano needle with buffering beam for single cell stiffness measurement by nanorobotic manipulators inside ESEM

Single cell´s mechanical property characterization is important for the understanding of the cell´s condition and activity. In this paper, a novel nanoneedle was proposed for single cell stiffness measurement inside an environmental scanning electron microscope (ESEM). The nanoneedle with a buffering beam was fabricated from AFM (atomic force microscopy) cantilever by nano fabrication technique. The beam will deform when the needle tip touched the single cell. Therefore, the stiffness of the single cell can be calculated based on the beam deflection and the indentation on the cell surface. Here, yeast cell was chosen as the biology sample and put on the substrate inside ESEM chamber. The nanoneedle was driven by a nanorobotic manipulator, which has three degrees of freedom, i.e. X, Y and Z translation. The deformation of the nanoneedle and single cell can be got from the ESEM imaging directly. The result shows that the stiffness of a single yeast cell is around 8.7 MPa by using this nano indentation method.