License for piconewtons transfer standard with micro-electro-mechanical systems (MEMS)

A research institute active in metrology in Germany has developed a piconewtons transfer standard with micro-electro-mechanical systems (MEMS). The standard is applicable for the calibration of atomic force microscopes (AFMs) as the bending stiffness of their cantilevers can be exactly determined. Accurate determination of bending stiffness of the cantilever is important for accurate force measurement, and satisfactory measurement techniques are currently lacking. The new transfer standard of the German research institute calibrates these smallest forces for use in force spectroscopy and is suitable for the integration in state of the art standard measuring equipment. The system consists of a reference surface with defined gap, under which a punch is mounted, which is controlled by a MEMS unit. For calibration the test tip moves over the surface to the indentation. The probing force of the test tip leads there to a proportional deflection of the piconewton-transfernormal punch. With the aid of the known stiffness of the standard and the deflection, the probing force can now be calculated or the sensor signal of the piconewton transfer standard will be displayed directly. The clever design of the angle at the gap ensures that it can be used for common cantilevers. Calibration is possible without electronic control, purely passive calibration is possible. Both, atomic force microscopes as well as stylus instruments with stiffnesses in the range between 1 millinewtons per meter (mN/m) and 25 kilonewtons per meter (kN/m) can be calibrated with the new force transfer standard. With the help of force spectroscopy, spatial structures of protein molecules could be investigated in pharmacy and medical technology for better understanding of their functions. It could also be used in material research. In this area the mechanical structures of e.g. dirt-repellent surfaces can be analysed. In particular, the passive use, without electronic control, is interesting for manufacturers of stylus instruments. Previous methods for determining the stiffness of the cantilever do not achieve sufficiently precise measurements, which are needed for force spectroscopy. Therefore, the research institute developed a more precise method, which is easy to integrate into commercially available devices. The institute looks for licensees and partners for technical cooperation agreements.