Electrical, Thermal, and Mechanical Properties of Nano Mechanical Structures
Gen Hashiguchi, Associate Professor, Faculty of Engineering, Kagawa University
Hiroyuki Fujita, Professor, Institute of Industrial Science, The University of Tokyo
Manabu Ataka, Assistant, Institute of Industrial Science, The University of Tokyo
1. Introduction

bio-nano objects, such as DNA, thereby necessitating a system capable ofroutinely measuring such objects. To aid in these measurements, we aredeveloping integrated microactuator devices called nano-grippers andnano-testers. Please take a look at these devices, as well.

To achieve practical nanotechnology, which has garnered muchattention in recent years, it is essential to establish a method ofevaluating small matter on the nano order. In this study, weinvestigated methods for measuring electrical, thermal, andmechanical properties of nano-size matter using micromachinetechnology. There are two conceivable methods for measuring theproperties of nanostructures. One method integrally forms ananostructure with an approachable electrode structure. The othermethod uses multiple nanoprobes to probe nanostructures. The
following is a report of these two methods as studied in our research.

Si wire20ku x15,000

1 µm 020203

Magnified viewActuator

2. Four-Terminal Freestanding Silicon Nanostructure
We produced a four-terminal nanostructure for measuring thethermal response of silicon nanostructures. Fig. 1 shows an SEM
photograph of this element. The cross-section of the wire is shaped as anisosceles triangle with a width of about 0.5 µm and a length of 4 µm. Fig. 2
shows the inverse relationship between input power and the resistancevariations of the element. We can see there is a sharp peak in theresistance at a particular input power. Fig. 3 shows the properties of thiselement as a flow sensor and its frequency characteristics, illustrating thatan air flow can be measured even by such a nano scale element.

20ku x2,000

1 0µm02020120ku x1,000

1 0µm

011222

Fig. 1 SEM photo of a four- Fig. 4 An integrated electrostatic
terminal free-standing
actuator type mechanicalsilicon elementnanostructure testing device
Electrical resistance [Ω]1000

3. Silicon Nanostructure Testing Device Using
an Integrated Microactuator Element

Power [1/W]100
1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 1.E+09 1.E+10

We developed a process for integrally forming a silicon wirestructure with an electrostatic actuator in order to study themechanical properties of nanostructures. Fig. 4 shows an SEM photo ofthis device. This device is manufactured with a three-layer SOI wafer,
wherein the electrostatic actuator is formed by the middle SOI layer
and a nanostructure having an electrode terminal is formed by the top
SOI layer. A special technique is implemented in this process toproduce the nanostructure in freestanding form.

4. Conclusion
This was a report on nano-scale measurements using micromachining
technology. The present study was limited to devices for measuring siliconnanostructures. However, there has recently been increasing interest in

5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0

Output [dB]

Voltage [V]Fig. 2 Resistance variations in the free-standing nano wire

20.1
0-2-4-6-8-10-12-14-16

1

10100

Frequency [kHz]0102030405060
Velocity [m/s]

7080

90100

Fig. 3 Characteristics of a flow sensor employing a free-standing silicon nano wire

Integration of Chemical Systems toward Artificial Organs
Takehiko Kitamori, Professor, Department of Applied Chemistry, School of Engineering, The University of Tokyo
Hideaki Hisamoto, Lecturer, Department of Applied Chemistry, School of Engineering, The University of Tokyoa simple combination of macroscale reaction processes, the same series on amicrochip only took 30 minutes. This indicates that by introducing a sugar
into an artificial organ, such as a microchip, a colored chemical species isefficiently produced through various chemical processes.

1. IntroductionIt is believed that chemical conversion processes performed by organs,including metabolism, detoxification, and bio-synthesis, consist of cell response,enzymatic reactions, synthesis, and the like that progress very efficiently as aseries of reactions within micro spaces, such as capillaries and cell surfaces.
We concluded that we could use microchannels, having a width of several
tens to several hundreds of microns and manufactured on a microchip, in
place of capillaries and accumulate elementary processes of organs, such ascell response, enzymatic reactions, and synthesis to achieve an efficientmodel of an artificial organ on a microchip, which would transcend a simple
combination of macroscale reaction processes. The objective of this study was
to detect multiple stage chemical conversion processes of sugar by integratingcell response, enzymatic reactions, and synthesis.

3. Conclusion
The integration of elementary processes in a micro space, as describedabove, is extremely important to the realization of organ functions andother advanced biological functions on an artificial device. In the future wehope to be able to construct even more complex biological function
mimicking devices by integrating many technologies, such as molecular
fixation and a technique for fabricating functional separation membranes
on a single chip. We also hope to apply this new knowledge to reproductionengineering and artificial organ development.

2. Integrating Modeled Chemical Reactions of an
Organ on a Microchip
Fig. 1 shows our designed microchip, which comprises a cell culturebath, enzymatic reaction section, synthesis section, and sensing section.
When lipopolysaccharide is introduced from an external source as a sugar andreacted with microphage, nitric oxide (NO) is produced. The generated NO isimmediately converted into NO2 and NO3 by a reaction with water. Of these,
NO3 is converted into NO2 by an enzyme introduced through a separate
channel and subsequently generates a colored chemical species through areaction with a mixing reagent introduced through the next channel. Hence, it
is possible to confirm a series of chemical conversion processes by detecting
this colored chemical species through a thermal lens microscope.
While it required half a day to detect the above series of reactions using

EnzymeEnzymatic reaction

Synthesis

Cell culture/response
Sugar

3cm

Mixing reagent
7cm

Product
Detection

Fig. 1 Integrating Organ Chemical Reactions on a Microchip

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