Hiroyuki Fujita, Ph.D.
January 20, 2011
"Nano Hand-Eye System for Science and Engineering"
In order to enhance scientific knowledge and engineering capability in nano scale, it is crucial to develop manipulation tools, i.e. nano hands, for handling an individual nano object or molecule. The tool must be combined with an advanced characterization method having both single atomic or molecular level sensitivity and simultaneous imaging capability, i.e. nano eyes. The author and his colleges have intensively investigated MEMS (micro electro mechanical system) design, fabrication and its application to nano and bio technologies . Nano scientific research using MEMS devices covers the tensile testing of nano contacts in transmission electron microscope (TEM) for in situ atomic level observation of deformation , micromachined Brownian motors  and MEMS tweezers for capturing and characterizing DNA and other linear molecules electromechanically . MEMS for bio technology includes micromachined fL-chambers and heaters to allow single-molecular level enzymology , and the integration of bio molecular motors in MEMS for direct sorting and transportation of specific sample molecules . In this talk, I will focus on two topics; nano tensile testing in TEM and a nano transportation device driven by bio molecular motors. We designed MEMS opposing tips for the experiments under TEM observation and investigated the formation-retraction-fracture process of silicon nano contacts; the process strongly depended on atomic transport [2, 7]. MEMS devices can provide higher and more precise control over long time (hours or even days) and better temperature stability than conventional piezoelectric actuators. Furthermore, the integration of thermal or strain sensors or heaters enables multi-functional MEMS devices that can fit in the narrow space in TEM. We have developed a characterization system that is capable of simultaneous TEM visualization and electro-mechanical measurement of a nano object manipulated by a MEMS device. We have observed extraordinarily large (2000 %) elongation of a silicon nano wire under mechanical tensile stress. Its basic mechanism was examined by comparing experimental results to theoretical models and molecular dynamic calculation. The conveyance of bio molecules in cells is conducted by the microtubule network on which vesicles, filled with target molecules and coated with kinesin, move around. We have studied the device that imitates the intracellular nanotransport system. Previously, we succeeded in building a molecular sorter by using kinesin motion along microtubules . Kinesin coated beads were used as carriers along oriented microtubules. For such a system, many microtubules were used to coat the surface for kinesin motion. However, to build a real nano-scale transport system, single microtubule manipulation should be achieved. We have developed a novel method to build a rail system based on single microtubule capturing and relocation by using silicon micro tweezers under a high-resolution fluorescent microscope. The relocated microtubules act as a nano monorail for kinesin-coated beads . The beads moved along the artificial network of microtubules towards predetermined directions. This technique is useful for engineering purposes such as a nano-scale molecular sorter.
 H. Fujita(Ed.), “Micromachine as tools for nanotechnology (Microtechnology and MEMS series)”, Springer, 2003  T. Ishida, K. Kakushima, M. Mita, H. Toshiyoshi1, H. Fujita, “In-situ TEM Observation of Crystal-Facet-dependent Self-Rearranging Gold Atoms under Tensile Stress Controlled by MEMS Nanoprobe Positioner”, Transducers ‘07, Lyon, France, June 10-14 (2007) pp. 2505-2508.  E. Altintas, K.F. Boehringer, H. Fujita “Numerical and experimental characterization of three-phase rectification of nanobead dielectrophoretic transport exploiting Brownian motion”, Sensors & Actuators: A. Physical, 154 (2009), pp. 123-131  M. Kumemura, et al. ChemPhysChem, 8, p.1875, 2007  Y. Rondelez,, et al., Nature, 433, p.773, 2005.  M.C. Tarhan, R. Yokokawa, F.O. Morin, S. Takeuchi, H. Fujita “Sorting and Direct Transportation of Target Molecules by Bio Molecular Selectivity and Motor Function”, IEEE Conf. on MEMS, Kobe, Japan, Jan. 21-25 (2007) pp. 23-26.
 T. Ishida, Y. Nakajima, K. Kakushima, M. Mita, H. Toshiyoshi, H. Fujita, “Design and fabrication of MEMS-controlled probes for studying the nano-interface under in situ TEM observation”, J. Micromech. Microeng. 20 (2010) 075011 (8pp)/doi:10.1088/0960-1317/20/7/075011
 M.C. Tarhan, D. Collard, C. Bottier, R. Yokokawa, M. Hosogi, G. Hashiguchi and H. Fujita, "Isolation and Manipulation of Single Microtubule by Silicon Microtweezers", The 12th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS'08, pp.862-864, San Diego, CA, USA, (2008)