Monolithically Integrated Two-Axis Microtensile Tester for the Mechanical Characterization of Microscopic Samples

This paper describes the first monolithically integrated two-axis microtensile tester and its application to the automated stiffness measurement of single epidermal plant cells. The tensile tester consists of a two-axis electrostatic actuator with integrated capacitive position sensors and a two-axis capacitive microforce sensor. It is fabricated using a bulk silicon microfabrication process. The actuation range is +/-16 m along both axes with a position resolution of 20 nm. The force sensor is capable of measuring forces up to +/-60 N with a resolution down to 60 nN. The position-feedback sensors as well as the force sensor are calibrated by direct comparison with reference standards. A complete uncertainty analysis through the entire calibration chain based on the Monte Carlo method is presented. The functionality of the tensile tester is demonstrated by the automated stiffness measurement of the elongated cells in plant hairs (trichomes) as a function of their size. This enables a quantitative understanding and a model-based simulation of plant growth based on actual measurement data.

[1]  Bradley J. Nelson,et al.  Real-time Rigid-body Visual Tracking in a Scanning Electron Microscope , 2007, 2007 7th IEEE Conference on Nanotechnology (IEEE NANO).

[2]  Yu Sun,et al.  Calibration of Multi-Axis MEMS Force Sensors Using the Shape-From-Motion Method , 2007 .

[3]  Bradley J. Nelson,et al.  Real-time rigid-body visual tracking in a scanning electron microscope , 2007 .

[4]  A. Geitmann,et al.  Mechanics and modeling of plant cell growth. , 2009, Trends in plant science.

[5]  R. Mullen,et al.  Electrostatically actuated failure of microfabricated polysilicon fracture mechanics specimens† , 1999, Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[6]  D. P. Potasek,et al.  Characterizing fruit fly flight behavior using a microforce sensor with a new comb-drive configuration , 2005, Journal of Microelectromechanical Systems.

[7]  Bradley J. Nelson,et al.  Design and calibration of a MEMS sensor for measuring the force and torque acting on a magnetic microrobot , 2008 .

[8]  Martyn C. Davies,et al.  Comparison of calibration methods for atomic-force microscopy cantilevers , 2002 .

[9]  Jon R. Pratt,et al.  Review of SI traceable force metrology for instrumented indentation and atomic force microscopy , 2005 .

[10]  B. Nelson,et al.  Monolithically Fabricated Microgripper With Integrated Force Sensor for Manipulating Microobjects and Biological Cells Aligned in an Ultrasonic Field , 2007, Journal of Microelectromechanical Systems.

[11]  Ji Won Suk,et al.  Microsystem for nanofiber electromechanical measurements , 2009 .

[12]  Noel C. MacDonald,et al.  A millinewton microloading device , 1996 .

[13]  H. Kahle,et al.  Absolute gravity measurements in Switzerland: Definition of a base network for geodynamic investigations and for the Swiss fundamental gravity net , 1981 .

[14]  Fumihito Arai,et al.  Parallel-beam sensor/actuator unit and its application to the gyroscope , 2000 .

[15]  Bradley J. Nelson,et al.  Three-axis micro-force sensor with sub-micro-Newton measurement uncertainty and tunable force range , 2010 .

[16]  Horacio D Espinosa,et al.  An electromechanical material testing system for in situ electron microscopy and applications. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[17]  Martin Hülskamp,et al.  Plant trichomes: a model for cell differentiation , 2004, Nature Reviews Molecular Cell Biology.