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JAPAN NANONET BULLETIN
-- 91st Issue -- March 8, 2007
Nanotechnology Researchers Network Center of Japan
Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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IN THIS ISSUE
Nanonet Interview:
"Opening up a new world of nanodiamonds
-- Dispersing nanodiamonds --"
Eiji OSAWA, Chief Executive, NanoCarbon Research Institute Ltd.
Young Researchers' Introduction:
"Nanoinjection into ES cells with a single-cell manipulation
supporting robot"
Mikako SAITO, Associate Professor, Department of Biotechnology and
Life Science, Tokyo University of Agriculture and Technology
Nano Info:
"4th Sweden-Japan Workshop on Bio-Nanotechnology (Nov. 13-14, 2006)"
-- NANO CALENDAR --
For information on nanotechnology related symposiums and conferences
held in the world,
http://www.nanonet.go.jp/english/calendar/
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NANONET INTERVIEW
Opening up a new world of nanodiamonds
-- Dispersing nanodiamonds --
(Issued in Japanese: March 8, 2006)
Eiji OSAWA, Chief Executive, NanoCarbon Research Institute Ltd.
In 1970, Prof. Osawa became the world's first scientist to predict the
existence of C60. The novel molecule, shaped exactly like a soccer-ball,
was first isolated in 1990 and fascinated scientists all over the world.
Almost 20 years after the fullerene fever, Prof. Osawa is now working on
the same small carbon particles, but this time on the nano-sized version
of the oldest known carbon, diamonds, called detonation nanodiamonds,
which other researchers have neglected for too long time even though
they were discovered in 1963.
In 1999, while Prof. Osawa was still working on C60, he encountered a
sample of nanodiamond produced in Russia. He was told that the grey
powder was produced by detonation of explosives, a method hardly known
at that time outside Russia. In western industrialized countries,
microdiamond particles were produced by the so-called shock method and
used as the polishing materials. These two methods sound similar and
both use shock waves from the detonation of explosives to grow diamond
crystals, but they are totally different: the 'detonation method'
produces single crystals of nanodiamond particles while the 'shock
method' produces polycrystals of microdiamonds. In the shock method,
graphite is exposed to high-temperature and high-pressure shock waves
generated by external explosion to effect phase transition of graphite
into diamonds. In contrast, the detonation method uses only the
explosives in the absence of any other carbon source. Oxygen-deficient
explosives like TNT and RDX are detonated in an inert atmosphere like
water or CO2 to produce soot particles, at least one half of which is
nanodiamond.
The discovery of detonation nanodiamonds is a surprise to every western
scientist, who heard about it in the 1990th. However, the story does not
end at this point. Prof. Osawa soon found out that detonation
nanodiamonds were not separated particles as the powder X-ray analysis
initially indicated, but multi-level aggregates consisting of at least
three discrete average size groups: 30 microns, 3 microns and 100-200 nm.
The smaller the size of the aggregate, the stronger its aggregation
energy is. The smallest one is especially tenacious, and there was not
a way to disaggregate. We call it 'core agglutinates'.
Nanodiamonds cannot fully exhibit the characteristics of nanoparticles
as long as they remain aggregated at any level. Low-level and larger
aggregates disappear by applying supersonic waves, but the core
agglutinates only become a little smaller. Prof. Osawa analyzed the
formation process of nanodiamonds and came up with the idea that primary
particles in the core agglutinates are bonded to each other chemically.
How can these agglutinates be destroyed? Prof. Osawa says, "Fortunately,
I could break up the agglutinates with high-speed beads milling. I put
the agglutinates together with a large excess of hard ceramic beads into
a special milling machine made from the same ceramic material. Usually
the beads mills are used to pulverize soft crystals, like TiO2 or ZnO,
or soft materials, like wheat flour, into nano-sized particles by
milling them with beads made from a harder material, but in this case,
diamond is the hardest material on earth. Hence, we cannot crush them.
What we expected was to cleave the chemical bonds, which are disorderd
and not as strong as those in diamond crystal, that held the primary
particles of the nanodiamonds in its core agglutinates. We used 30
microns sized zirconia beads for this purpose and the experiments worked."
Thus, Prof. Osawa obtained 4 nm sized primary particles of nanodiamond
for the first time 40 years after the discovery of detonation method.
Nanodiamonds are being produced as colloidal solution and also in the
form of loose aggregate powder that can be dispersed back into primary
particles easily. Dispersed or dispersible nanodiamonds retail for
3,150 yen per gram at the moment, but the price will decrease quickly as
the production method is improved (in progress) and consumption
increased. Prof. Osawa says, "With dispersed single-digit-nano diamond
particles available to scientists and engineers in large quantities, R&D
efforts to apply nanodiamonds for purposes other than polishing material
will increase."
A nanodiamond particle produced by the detonation method is comprised of
only about 5,000 carbon atoms. The primary particles of nanodiamonds
have such a large specific surface area of 500 m2/g that they tend to
absorb impurities and are quickly oxidized by harsh treatment in air.
Prof. Osawa even found out that during beads milling some of the surface
diamond carbon atoms transform themselves into graphitic carbons; hence,
it was necessary to clean up the surface in a separate step afterwards.
However, the large surface area makes it possible to modify the surface
to give new properties and functions to the whole particle. For example,
fluorination produces ideal nano-bearings that can be used for dry
lubricants for micromachines. Bombardment with accelerated nitrogen ions
followed by annealing below 1000 dgree C caused a high concentration of
nitrogen atoms or molecules to be trapped in the vacant sites of the
diamond crystal lattice. Such a diamond particle fluoresces intensively
with a yellowish green color and is valuable for cell imaging in
biomedicine. Prof. Osawa says "These high-nitrogen nanodiamonds will
eventually find uses in the cell therapy as nanodiamonds have been
recently found to be as highly biocompatible in contrast to a few other
nanoparticles which are potentially toxic. Nitrogen implantation into
nanodiamonds is also a promising route to n-type semiconductors."
The global market for artificial diamonds as industrial materials is
about 5 billion yen a year, a surprisingly modest level considering the
known excellent properties of these diamonds. Prof. Osawa estimates that
only 200 tons of microdiamonds are being produced annually and consumed
only for two major purposes: polishing stones and sintered coating for
cutters and drills. Prof. Osawa says, "I do not think it wise to enter
into these small markets. So, I would like to concentrate on discovering
new markets making use of inherently excellent properties of diamond and
also of its unique size of single-digit-nano. I have already mentioned a
few uses of nanodiamond as individual particles. Another obviously
interesting direction would be to improve the performance of bulk
materials, like plastics, resins, metals, alloys, ceramics and glasses,
by dispersing nanodiamond particles to act as the reinforcement
component. However, here we face a new technical obstacle: how to
disperse the aggregation-prone nanodiamond particles into a solid matrix.
We are now seriously working to find new ways to disperse nanoparticles
into the solid. We already found that the so-called sol-gel process can
be advantageously applied for certain purposes, and a variation of
mechanical alloying where large balls are replaced with microbeads also
works well."
"Nanodiamonds will be a very attractive material," he says. "They may be
used as a material for wear-resistant auto parts or for high-strength
structural parts of aircraft. To use nanodiamonds for such things, their
price should be reduced further. I think nanodiamonds may become a very
inexpensive material once we have completed our new method of
purification, on which we are now working. The starting materials, i.e.,
explosives, are in large surplus worldwide, and they are cheap chemicals."
Prof. Osawa is also considering making use of the high transparency and
hardness of nanodiamonds for glass and other building materials. He says,
"The type of nanomaterials that researchers want to develop most is high
thermal conductive films. Actually, we have already succeeded in
fabricating films, fibers and whiskers from nanodiamond particles by
making use of the unique self-organization properties of these particles,
which arises from oxygen-containing functional groups on the particle
surface."
Prof. Osawa says, "I often easily come up with very interesting ideas.
Many people believe that I developed the idea about the structure of C60
through computer calculations. But the idea came to me when I saw a
soccer ball pattern while thinking about a three-dimensional aromatic
series model made of five- and six-membered rings using the structure of
corannulene as a reference. Corannulene had been synthesized a little
before I started looking for such a model." This speculation arose from
the fact that Prof. Osawa used to be widely known as a computational-
theoretical scientist. However, when a new idea comes, it comes through
a flash of instinct or some kind of intelligent guess backed by
experience. He says he is lucky because he had his educational and
research background in chemistry. He says, "Chemists are the best
fabricators of things. Polymer chemists have been developing methods to
characterize things that cannot be crystallized, sublimed or distilled.
These methods can be applied to nanoparticles. I hope more chemists will
contribute to building the foundation of nanoscience."
Prof. Osawa began and now runs a start-up company. He says, "The dreams
of chemists are limitless. Typical dreams are to find materials that are
harder than diamonds and to synthesize ferromagnetic materials from
carbon, which are much lighter than iron. I cannot quit my career as
a researcher, because I have been having these dreams one after another
since C60 was discovered."
(Interviewer: Kuniko Ishiguro, Cosmopia Inc.)
For more information including figures,
http://www.nanonet.go.jp/english/mailmag/2007/091a.html
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YOUNG RESEARCHERS' INTRODUCTION
Nanoinjection into ES cells with a single-cell manipulation
supporting robot
(Issued in Japanese: January 26, 2005)
Mikako SAITO, Associate Professor, Department of Biotechnology and
Life Science, Tokyo University of Agriculture and Technology
The large amount of genomic information that is available today has
caused a shift in the way genetic diseases are investigated. Rather than
searching for the genes that cause a particular disease, investigators
determine what diseases are caused by altering a particular known gene.
Disease model cells are just the materials to meet this need. Using
microinjection, multiple genes, as well as the drugs to modify them, can
be simultaneously, or sequentially, introduced into cells. In comparison
with other methods, such as lipofection and electroporation,
microinjection is more advantageous because genes can be introduced into
the same cell with prescribed timing. Recently, the precision of
positionally controlling the injection site has markedly improved
because of the development of related micromanipulation technologies.
However, microinjection requires additional tasks, such as cell search,
cell support if necessary, cell storage, and the microscopic imaging of
the responses of target cells, and therefore, microinjection is still
tedious and difficult work. In order to facilitate the extra tasks, we
developed a single-cell manipulation supporting robot (SMSR). With SMSR,
operators can concentrate all of their attention on the microinjection
step. The advantage of using the robot was previously demonstrated with
rice protoplasts and mouse fibroblasts.
Various model cells will be made by injecting gene alterating agents
into ES cells. A supporting robot for single-cell manipulation has been
developed to facilitate the complicated procedures of nanoinjection and
to establish a high throughput process for the creation of disease model
cells. Our research will lead to new gene therapy methods and also to
new screening methods of novel medicines.
For more information including figures,
http://www.nanonet.go.jp/english/mailmag/2007/091b.html
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NANO INFO
4th Sweden-Japan Workshop on Bio-Nanotechnology (Nov. 13-14, 2006)
(Issued in Japanese: December 6, 2006)
The fourth Sweden-Japan Workshop on Bio-Nanotechnology was held at
National Institute for Materials Science (NIMS), Tsukuba, November 13-14,
2006. The Japanese Ministry of Education, Culture, Sports and Technology
(MEXT) and the Swedish Foundation for Strategic Research held their
first joint workshop in Sweden in 2002, the second in Japan in 2003, and
the third in Sweden two years later. They conducted a fourth workshop in
Japan, attended by 50 participants including 11 Swedish speakers, 16
Japanese speakers and eight presenters for a poster session.
Dr. Lars Rask of the Swedish Foundation for Strategic Research and Mr.
Masayuki Takahashi, Director of the Office for Materials Science and
Nanotechnology Development at MEXT, gave opening and welcome speeches.
Prof. Masuo Aizawa, President of the Tokyo Institute of Technology, and
Prof. Thomas Laurell at Lund University who have been playing key roles
in organizing the workshops, explained to the attendees how the
workshops have been conducted so far, that many speeches at the workshop
are about applications of bio-nanotechnology and that cell biology is
currently attracting a great deal of attention from many researchers.
They also talked about that one of the workshop's objectives is to
expand interaction among researchers of the two countries by having more
first-time participants.
As the opening presentation, Prof. Aizawa delivered a speech entitled
"Advances and Challenges of Bio-Nanotechnology/Nano-biotechnology," in
which he talked about this field's leading trend and outlook. Session I
on the first day was about Nano-bioelectronics, Session II about
Manipulation and analysis of cell and biomolecules on chip, Session III
Biomedical application, and Session IV Nanoscience and nanomaterials for
biotechnology. On the second day, Session I was on Biomimetics material
and bio-sensing application, Session II Biomolecular detection, Session
III Cell and protein based device, and Session IV was a poster session.
The results of much recent research were presented, and discussed by
participants actively. Among other studies presented, Kyushu University
Professor Yoshiki Katayama's "New Concept for Gene Therapy using
Intracellular Signal-Responsive Gene Regulation System" attracted much
attention from participants. His research is aimed at directly
distinguishing cancer cells from normal ones. This is now very difficult
because researchers have been focusing attention only on differences in
the surface structures of the two types of cells. Prof. Mats Nilsson at
Uppsala University presented "Amplified Single-molecule Detection for
Bioanalytical and Single-cell Biology Studies." The professor introduced
technology that enables researchers to analyze molecules in individual
cells at the single nucleic acid molecular level. Both these research
works were recognized by the participants as a remarkable advancement.
In the poster session, Japanese researchers who had participated in a
program for dispatching young researchers presented their research,
taking advantage of their strong relationship with their Swedish
counterparts. The program for young researchers is designed to promote
interaction among researchers of the two countries in a wide range of
fields.
Results of bio-nanotechnology research will be used for medical
applications. In the opinion-exchange gathering after all sessions on
the first day, some participants said the key challenge they face is
deciding how to promote not only cooperation between the medical and
engineering fields but also the fusion of these sectors in an
environment where researchers tend to concentrate their activities in
limited areas. Some Swedish participants also said they are conducting
joint research for medical applications, but reported difficulty in
carrying out in vivo research. On November 15, the 11 Swedish
participants joined a tour of nanotechnology and biotechnology related
laboratories -- the National Institute for Materials Science (NIMS), the
National Institute of Advanced Industrial Science and Technology (AIST),
and NEC's Fundamental and Environmental Research Laboratories.
(By Takao Kitamura, nanonet)
For more information including figures,
http://www.nanonet.go.jp/english/mailmag/2007/091c.html
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