| POLYMERS Vol.62 No.2 |
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COVER STORY
Creation of Inorganic Materials Based on Biopolymers |
| COVER STORY: Highlight Reviews |
| Fabrication and Application of Bio-Nanomaterial by Biotemplates | Kenji IWAHORI, Ichiro YAMASHITA |
| <Abstract> There
are many methods for fabrication of nanomaterials in the world. Recently,
many researchers are attracted to the “bio-template method” using small
protein cages to synthesize uniform nanomaterials. These small protein
cages are used as templates to synthesize nanoparticles or nanowires
for nanotechnology such as fabrication of nano-electronic devices. This
method is an environmental friendly method, because the synthesis of
nanomaterial
was achieved in aqueous solutions at room temperature. There are many
kinds of nanoparticles and nanowires that are synthesized by this method.
I introduce here the
fabrication of nanomaterials by the bio-template method and some applications
using synthesized NPs and finally a prospect of bio-nanomaterials. Keywords: Nanomaterial / Nanoparticle / Ferritin / Nano-Devise / Bio-Template |
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| Biomimetic Materials Synthesis and Self-Assembly for Device Fabrications: What Have We Done and Where Do We Go with This Technology | Hiroshi MATSUI |
| <Abstract> Peptides
and proteins are advantageous to develop complex and hybrid 3D assemblies
and materials due to their robust assembling nature, templating capability,
and molecular recognition. This review covers how the field of peptide-based
material sciences/engineering started, and continues to discuss the evolution
of technology from 2D to more complex 3D assemblies. Unique features
include the large scale assembly of nanomaterials in precise location,
periodicity, and interparticle distance, difficult to accomplish by other
technologies. Applications of biomolecular assemblies can be expected
in the fields of electronics, photonics, solar cells, medical devices,
tissue engineering, and metamaterials. Keywords: Bionanotechnology / Peptides / Protiens / 3D Self-Assembly / Biomaterials / Biomimetics |
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| Bioinspired Synthesis of Inorganic Crystals: Molecular Control of Crystal Growth | Hiroaki IMAI, Yuya OAKI |
| <Abstract> The
structural design of biominerals consisting of building blocks with the
incorporation of organic polymers has attracted the interest of researchers
in a broad range of chemistry disciplines. The complex and hierarchical
architectures of biominerals are formed
with molecular control in an aqueous solution
system at ambient atmosphere. In this article, the bioinspired
formation of hierarchical inorganic crystals exhibiting a wide variety
of complex morphologies are reviewed. The molecular control for the inorganic
crystals would
be appliable as a smart technique for the fabrication of functional
nanoscale materials. Keywords: Biomineral / Molecular Control / Crystal Growth / Organic Template / Soluble Molecule / Self-Organization |
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| COVER STORY: Topics and Products |
| Nanointerface Molecules from Material-Binding Antibodies | Mitsuo UMETSU, Takamitsu HATTORI, Izumi KUMAGAI |
| <Abstract> Antibodies,
with their high affinity and specificity, are widely utilized in the
field of protein engineering, medicinal chemistry, and nanotechnology
applications, and our recent studies have demonstrated the recognition
and binding of antibodies to the surface of inorganic material. High
affinity material-binding antibody fragments are generated on the single
variable domain of the heavy chain of a heavy chain camel antibody (VHH)
by a combination of peptide-grafting and phage-display techniques and
they can be used for one-pot functionalization of nanoparticles as interface
molecules. Multivalent and bispecific antibodies which are constructed
on the material-binding VHH platform by means of fusion technology functionalized
inorganic nanoparticles in one pot, and these functionalized nanoparticles
can be used to obtain surface plasmon resonance scattering images of
cancer cells and to spontaneously link two different nanomaterials. Here, we propose the bispecific antibodies
as convenient interface molecules in nano-sized world. Keywords: Antibody / Nanoparticle / Evolution Technology / Interface Molecule / Assembly |
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| Technology for Bio-Silica Fabrications Inspired by Diatom Shell Formation: Development and Perspective | Yusuke MATSUDA |
| <Abstract> Biomineralization
of silicate is commonly observed in nature. Lessons from diatom silica
shell (frustle) formation have indicated that, as one of the observed
natures of a frustle-forming factor, Silaffin, silica forming peptides
are strongly cationic. Our recent study demonstrated that basic amino
acids, lysine and arginine, also mineralize silicate by themselves, although
required concentrations of these free amino acids were above 5 mM while
cationic peptides required for efficient silica formation were about
30 nM in the presence of 0.1 M silicate, indicating efficiency of more
than two orders of magnitude higher compared to free amino acids. Amphipathic
α-helix peptide was obtained from a diatom pyrenoid forming carbonic
anhydrase, PtCA1, and basic amino acids were introduced to this helix
by gene engineering. Resulting cationized-diatom-pyrenoid-forming factor,
CDPF, revealed biosilica formation with high activity which is equivalent to that of diatom Silaffin. Our study
demonstrates a high potential to create silica-based materials using
peptides which are obtained from natural resources or protein engineering. Keywords: Diatom / Biosilica / Cationic Peptide / Protamine |
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| Metal-Complexed Organic Nanotubes Self-Assembled from Peptide Lipids | Masaki KOGISO, Masaru AOYAGI |
| <Abstract> Organic
nanotubes (ONTs) are expected as a novel nano-container for versatile
functional materials. Peptide lipids comprising of a glycyl-glycine and
an alkyl chain self-assemble to form the organic nanotubes through unique
polyglycine-II type hydrogen-bond networks. Metal-complexed organic nanotubes
(M-ONTs) are unique ONTs made of metal-complex of the peptide lipids.
When an aqueous solution of metal salt was added to a dispersion of the
peptide lipids in alcohol, M-ONTs were produced immediately. We can obtain
more than 100 g of dry M-ONTs using 1 L of water-alcohol mixture in a
few hours. Metal ions exist both on the inner- and outer surfaces and
in-between bilayer membranes. These M-ONTs are expected as novel metal
or metal-organic hybrid nanomaterials through metallization using organic
layers as templates. Applications as a catalyst were also investigated.
Single bilayer Ni-ONT showed high catalytic activities toward the oxidation of a variety of organic molecules. Keywords: Metal Complex / Organic Nanotube / Peptide / Self-Assembly / Catalyst |
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| Development of Organic/Inorganic Hybrids Based on Polymer Templates | Tatsuya NISHIMURA |
| <Abstract> Biominerals
such as bones, teeth, the nacre of seashells, and the exoskeletons of
crustaceans are organic/inorganic hybrids with highly controlled hierarchical
structures. We have been inspired by the structure, properties and formation
processes of biominerals for the development of new functional hybrid
materials. We previously reported on the formation of thin films of inorganic
crystals based on this approach. The resulting hybrid materials consisting
of inorganic crystals and organic polymers exhibited a wide variety of
morphologies. Here we discuss our recent results for the development
of new inorganic/organic hybrid materials. Unidirectionally oriented
thin films and macroscopically oriented crystals have been obtained by
using functional polymer templates. Keywords: Biomineralization / Polymer Templates / Organic / Inorganic Hybrids / Recombinant Peptides / Calcium Carbonate |
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| Polymer Science and I: A Personal Account |
| Growing from “DA-RA-BU-CHI” | Hiroshi ENDO |
| <Abstract> Was myself able to really growing from DA-RA-BU-CHI, which means a foolish person in Toyama prefecture? As for the research life through all my fortunes will be continued. |
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| Front-Line Polymer Science |
| Layer-by-Layer Assembly, Where are You Going? | Katsuhiko ARIGA |
| <Abstract> Because
layer-by-layer (LbL) assembly has especially wide versatility in materials
applicability and easiness of procedure, it has been rapidly developing
in both fundamental science and practical application. This assembling
method resulting in sequence controlled multilayers on a nanometer-scale
thickness has been applied to various nanomaterials including graphene
and mesoporous materials. For example, LbL assembly of graphene nanosheets
and ionic liquids provided a sensor system with superior affinities for
aromatic compounds through guest accommodation within the well-defined
π-electron-rich nanospace. Mesoporous silica capsules were integrated
into LbL structures for development of a novel mode of drug delivery,
stimuli-free automodulated delivery. Release of liquid materials from
capsules in the LbL films possesses a stepwise profile even though no
external stimulus was applied. Recent other research examples also show high potentials of the LbL films in biomedical
applications and integration into device structures. Based on these
facts, I expect a bright future for the LbL technology. Keywords: Layer-by-Layer (LbL) Assembly / Thin Film / Nanomaterials / Graphene / Mesoporous Silica / Biomedical Application / Device |
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