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Current
Nanoscience
ISSN: 1573-4137
Current Nanoscience
Volume 4, Number 2, May 2008
Contents
Nanomaterials and Nanotechnologies: Approaching the
Crest of this Big Wave Pp. 119-129
Vuk Uskokovic
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Electrospun Polyacrylonitrile-Based Carbon Nanofibers
and Their Silver Modifications: Surface Morphologies and Properties
Pp. 130-137
Darunee Aussawasathien and Erol Sancaktar
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Preparation of Silver Nanoparticles by Microwave
Irradiation Pp. 138-140
Shilpa Sharma, Manisha Thakur and Manas K. Deb
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Mycosynthesis of Silver Nanoparticles Using the Fungus
Fusarium acuminatum and its Activity Against Some Human Pathogenic
Bacteria Pp. 141-144
Avinash Ingle, Aniket Gade, Sebastien Pierrat, Carsten
Sönnichsen and Mahendra Rai
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Biopolymer-Assisted Synthesis of Single Crystalline
Gold Disks by a Hydrothermal Route Pp. 145-150
Shuyan Gao, Shuxia Zhang, Kai Jiang, Shuxia Yang and
Weiwei Lu
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Influence of Temperature on TiO2
Nanoparticles Pp. 151-156
M. Pourmand and M.R. Mohammadizadeh
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Article]
Preparation of Large-Scale Highly Oriented ZnO
Noodle Arrays and Study on the Photoconductivity
Pp. 157-160
Xingfa Ma, Aiyun Liu, Huizhong Xu, Guang Li, Meng Hu and
Gang Wu
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An Algorithm for Constructing Wiener Matrix of
TUC4C8(R)
Nanotubes Pp. 161-165
Shahram Yousefi and Ali Reza Ashrafi
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Article]
Influence of Water Condensation on Charge Transport
and Electric Breakdown Between an Atomic Force Microscope
Tip, Polymeric, and (Semiconductor) CdS Surfaces
Pp. 166-172
Ewa Rowicka, Dmytro Kashyn, Michael A. Reagan, Tadashi
Hirano, Pavel B. Paramonov, Ivan Dolog, Robert R. Mallik and
Sergei F. Lyuksyutov
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Simultaneous Optimization of Cisplatin-Loaded PLGA-mPEG
Nanoparticles with Regard to their Size and Drug Encapsulation
Pp. 173-178
A. Beletsi, P. Klepetsanis, D.S. Ithakissios, S. Kounias,
A. Stavropoulos and K. Avgoustakis
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Article]
Size Effect on the Phase Stability of Nanostructures
Pp. 179-200
Q. Jiang and C. C. Yang
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Article]
Self-Assembly of Proteins and Peptides and their
Applications in Bionanotechnology Pp. 201-207
Karthikeyan Subramani, Ameen Khraisat and Anne
George
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Article]
Mono-Substituted 4,4’-Dimethyl-2,2’-Bipyridine
Ligands at the Solid-Liquid Interface: Study of the Molecular
Organization Pp. 208-211
Stephanie Hoeppener, Veronica N. Marin and Ulrich
S. Schubert
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Magnetic Driven Alginate Nanoparticles for Targeted
Drug Delivery Pp. 212-218
Gianni Ciofani, Vittoria Raffa, Yosuke Obata, Arianna
Menciassi, Paolo Dario and Shinji Takeoka
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Endothelial Cell Response to Narrow Diameter Nylon
Tubes Exhibiting Internal Nanotopography Pp. 219-223
C. Berry, D. McCloy and S. Affrossman
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Article]
Abstracts
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Nanomaterials and Nanotechnologies: Approaching the Crest
of this Big Wave
Vuk Uskokovic
Nanomaterials are typically considered as solid physical
structures that comprise grain boundaries at the resolution
of less than 100 nanometers, whereby nanotechnologies are
depicted as dealing with the design of various applications
based on employing the former. Some of the essential features
of nanomaterials and the scientific approaches to their investigation
are discussed in the course of this work. The real reason
for the current scientific and technological interest in the
physical effects at nanoscale is linked with the historic
trend of refinement of human knowledge and of the corresponding
ability to manipulate with the structural patterns of the
Universe. Interesting novel properties of nanomaterials are
presented as resulting from the interplay between the surface
properties and quantum effects at nanoscale. Examples of peculiar
combination properties that materials can exhibit with the
transition to nanosized form are mentioned, with a particular
emphasis on the nanoscopic aggregates of water molecules.
Specific challenges tied with the further growth of the field,
including the prospectives of functional superstructuring,
biomimicry, green chemistry, and the interdisciplinary approach
to research, are eventually outlined.
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Electrospun Polyacrylonitrile-Based Carbon Nanofibers and
Their Silver Modifications: Surface Morphologies and Properties
Darunee Aussawasathien and Erol Sancaktar
Polyacrylonitrile (PAN)-based carbon nanofibers (CNFs)
were prepared via the electrospinning process. Silver (Ag)
modifications of these CNFs were carried out using in-situ
Ag reaction as well as Ag coating methods. Ag modified CNFs
from both methods yielded higher electrical conductivity than
the neat CNFs due to the synergetic effect from the Ag nanoparticles.
The effects of fiber diameter, fiber aspect ratio and the
interconnecting network nature of the non-woven fiber mat
on the electrical and thermal decompositional properties of
as-prepared fibers were also investigated. The structural
characterizations of as-prepared fibers were performed using
SEM, Raman spectroscopy, WAXD, and TGA methods.
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Preparation of Silver Nanoparticles by Microwave Irradiation
Shilpa Sharma, Manisha Thakur and Manas K. Deb
Silver nanoparticles have been prepared under microwave
irradiation from a solution of silver nitrate. Different morphologies
of silver colloids with charming colors could be obtained
using two different reducing agents namely sodium citrate
(SC) and N1, N2-diphenylbenzamidine (DPBA) or simply amidine.
The structures of silver colloids were determined by TEM.
UV-Vis spectroscopy was used to follow the reaction process
and to characterize the optical properties of the resultant
silver colloids. The influence of two different mild conventional
and unconventional reducing agents on the morphology of silver
was investigated.
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Mycosynthesis of Silver Nanoparticles Using the Fungus Fusarium
acuminatum and its Activity Against Some Human Pathogenic
Bacteria
Avinash Ingle, Aniket Gade, Sebastien Pierrat, Carsten
Sönnichsen and Mahendra Rai
We report extracellular mycosynthesis of silver nanoparticles
by Fusarium acuminatum Ell. and Ev. (USM-3793) isolated
from infected ginger (Zingiber officinale). An aqueous
silver nitrate solution was reduced to metallic silver when
exposed to F. acuminatum cell extract leading to
the appearance of a brown color within 15-20 minutes. The
color is due to the formation of silver nanoparticles and
the excitation of surface plasmons. The optical spectrum showed
the plasmon resonance at 420 nm and analysis by transmission
electron microscopy confirmed the presence of silver nanoparticles.
The nanoparticles produced were spherical with a broad size
distribution in the range of 5-40 nm with average diameter
of 13 nm. The reduction of the silver ions occurs probably
by a nitrate-dependent reductase enzyme, which we found to
be present in the extra-cellular medium. We tested the silver
particles for their broad-band antibacterial activity on different
human pathogens. We observed efficient antibacterial activity
against multidrug resistant and highly pathogenic bacteria,
including multidrug resistant Staphylococcus aureus, Salmonella
typhi, Staphylococcus epidermidis, and Escherichia
coli. The synthesis of silver nanoparticles by the fungus
F. acuminatum may therefore serve as a simple, cheap,
eco-friendly, reliable and safe method to produce an antimicrobial
material.
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Biopolymer-Assisted Synthesis of Single Crystalline Gold Disks
by a Hydrothermal Route
Shuyan Gao, Shuxia Zhang, Kai Jiang, Shuxia Yang and
Weiwei Lu
This paper presents a hydrothermal method for the synthesis
and stabilization of gold nanodisks with a preferential growth
direction along the (111) plane inside environmentally–besign
sodium alginate sol by a one-step strategy without additional
reducing agent. This is carried out by transferring a sodium
alginate/HAuCl4 aqueous solution
into a stainless steel autoclave with a Teflon liner and heating
in an oven at 1000C for 30
h. Field emission scanning electron microscopy observation
indicates that the gold nanodisks are predominantly hexagonal
shape with micrometer-scale in diameter. Transmission electron
microscope, selected area electron diffraction, and X-ray
diffraction analyses show that the gold nanodisks grow preferentially
along the Au (111) plane. Some influential factors on the
growth of gold nanodisks are discussed. The results suggest
that the reactants’ concentrations and reaction time
are crucial to the formation of gold nanodisks and their growth
mechanism is tentatively explained.
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Influence of Temperature on TiO2
Nanoparticles
M. Pourmand and M.R. Mohammadizadeh
TiO2 nanocrystalline
powders were synthesized in the anatase phase by a modified
sol-gel method. The effect of calcination temperature was
also studied; XRD pattern of the sample dried at 100°C
showed a significant amount of amorphous content, and crystallinity
enhanced by increasing the calcination temperature. AFM images
demonstrate submicron agglomerate particles. FT-IR spectra
represent the formation of Ti-O-Ti bond for the as-prepared
powder. Following the trend of increasing the temperature
Ti-O bond was intensified. The pure anatase structure with
no undesirable impurity phase was resulted at 500°C. N2
adsorption and desorption isotherms pointed out a mesoporous
powder and the specific surface area using BET method was
measured 50 m2 /g, which
is corresponding to about 30 nm particle size. This is in
agreement with TEM and XRD results of particle average diameter.
Photocatalytic activity of the sample calcined at 500°C
was examined using methyl orange, which is comparable with
commercial TiO2 (P-25). This
method of nanopowder synthesis is presentable, since well-crystallized
nanoparticles with good surface area and photocatalytic activity
can be achieved.
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Preparation of Large-Scale Highly Oriented ZnO Noodle Arrays
and Study on the Photoconductivity
Xingfa Ma, Aiyun Liu, Huizhong Xu, Guang Li, Meng Hu and
Gang Wu
In order to obtain oriented nanostructured materials
for nanoelectronic/microelectronic applications, a simple
sol-gel method to form ZnO nano-structures under different
heat treatment conditions was investigated. The results indicated
that ZnO nanobelts could be obtained by the presence of small
amount of triethanolamine, which acted as soft template. The
orientation degree of the ZnO nanobelts was improved significantly
by optimizing preparation condition. Via adjusting the pH
of hydrothermal treatment, large-scale highly oriented ZnO
belt arrays were obtained. The XRD result agreed well with
that of the standard XRD results of ZnO. The photocurrent
of the oriented ZnO belt array increased about 2 orders of
magnitude after light exposure.
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An Algorithm for Constructing Wiener Matrix of TUC4C8(R)
Nanotubes
Shahram Yousefi and Ali Reza Ashrafi
The Wiener index of a graph G is defined as  ,
where V(G) is the set of all vertices of G and for x,y ε
V(G), d(x,y) denotes the length of a minimal path between
x and y. In this paper an algorithm for computing the Wiener
matrix of a TUC4C8
(R) nanotube T = T[p,q] is given. Using this
matrix, an exact expression is given, for the Wiener index
of T.
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Influence of Water Condensation on Charge Transport and Electric
Breakdown Between an Atomic Force Microscope Tip, Polymeric,
and (Semiconductor) CdS Surfaces
Ewa Rowicka, Dmytro Kashyn, Michael A. Reagan, Tadashi
Hirano, Pavel B. Paramonov, Ivan Dolog, Robert R. Mallik and
Sergei F. Lyuksyutov
Water condensation is shown to have a major influence
on electric charge transport and nanostructure formation in
polymer, and semiconductor-thin-film surfaces in the proximity
of a biased Atomic Force Microscope (AFM) tip. The water forms
a meniscus bridge between the AFM tip and the surface to form
a three-component system comprised of the AFM tip, water meniscus,
and the surface. The associated electric field in the meniscus
is spatially non-uniform and has a magnitude of the order
of 108 -1010
Vm-1. An intensive experimental analysis of the input and
output electric currents in the AFM tip/water meniscus/surface
system, performed at various relative humidity levels between
10 and 60%, indicates that the magnitude of the output current,
drained from surface, reaches values as large as several μA
which exceeds the input current, injected via the AFM tip
(0.01-10 nA), by at least an order of magnitude. This effect
is particularly evident when the relative humidity is greater
than 20-25%, suggesting that the water meniscus is ionized
by the strong electric field to produce electrons. Since the
method described here for nanopatterning is applicable for
materials with significantly different physical, electronic,
and optical properties, and is dependent largely on the ambient
humidity level and the strength of the electric field, it
is suggested that the method may be extended to a variety
of other materials.
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Simultaneous Optimization of Cisplatin-Loaded PLGA-mPEG Nanoparticles
with Regard to their Size and Drug Encapsulation
A. Beletsi, P. Klepetsanis, D.S. Ithakissios, S. Kounias,
A. Stavropoulos and K. Avgoustakis
A central composite experimental design was applied to
investigate the effect of five preparative variables on the
size and cis-platin encapsulation efficiency of poly(lactide-co-glycolide)-methoxy
poly(ethylene glycol) (PLGA-mPEG) nanoparticles. The nanoparticles
were prepared by a nano-precipitation process and were characterized
with regard to their morphology by scanning electron microscopy,
their size by photon correlation spectroscopy and their drug
content by atomic absorption spectroscopy respectively. The
preparative variables investigated were: solids concentration,
aqueous to organic phase volume ratio, temperature, rate of
organic phase addition in aqueous phase and agitation. The
nanoparticles prepared in this study appeared to be spherical
and rather homogeneous in size under the scanning electron
microscope. The size and the drug encapsulation of the prepared
nanoparticles ranged between 90-180 nm and 0%-40%, respectively.
The fitted model could adequately describe the experimental
data. The statistical analysis showed that all preparative
variables studied, except temperature, affected significantly
both the size and the drug loading of nanoparticles. The size
was most affected by the agitation whereas the loading was
most affected by the phase ratio. Significant interactions
between the preparative variables were also observed. The
“desirability function” approach was applied to
simultaneously optimize the nanoparticles with regard to their
size and cisplatin encapsulation. The predictive power of
the applied model was more satisfactory in the case of nanoparticles
size than with cisplatin encapsulation efficiency. It appears
to be feasible to select optimum conditions for the preparation
of PLGA-mPEG nanoparticles of cisplatin based on a central
composite design and the “desirability function”
optimization approach.
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Size Effect on the Phase Stability of Nanostructures
Q. Jiang and C. C. Yang
An extension of the classical thermodynamics to nanometer
scale has been conducted to elucidate information regarding
size dependence of phase transition functions and binary phase
diagrams. The theoretical basis of the extension is Lindemann'
s criterion for solid melting, Mott' s expression for vibrational
melting entropy, and Shi' s model for size dependent melting
temperature. These models are combined into a unified one
without adjustable parameters for melting temperatures of
nanocrystals. It is shown that the melting temperature of
nanocrystals may drop or rise depending on interface conditions
and dimensions. The model has been applied to size dependences
of melting enthalpy and atomic cohesive energy, critical temperatures
for glass transition, ferromagnetic transition, ferroelectric
transition, superconductor transition and ferromagnetic-antiferromagnetic
transition. Moreover, the above modeling has been utilized
to determine the size-dependent continuous binary solution
phase diagrams, bi-layer transition diagrams of metallic multilayers,
and solid transition phase diagrams after modeling the transition
entropy and atomic interaction energy functions of nanocrystals.
Moreover, the model has been used to predict size dependence
of diffusion activation energy and diffusion coefficient.
These thermodynamic approachs have extended the capability
of the classical thermodynamics to the thermodynamic phenomena
in the nanometer regime.
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Self-Assembly of Proteins and Peptides and their Applications
in Bionanotechnology
Karthikeyan Subramani, Ameen Khraisat and Anne
George
Self- assembly of biological molecules forms the basic
principle in the formation of complex biological structures.
Numerous proteins and peptides have been emerging as nanobiomaterials
due to their ability to self-assemble into nanoscale structures
like nanotubes, nanovesicles, helical ribbons and three dimensional
fibrous scaffolds. This mini review discusses the basic principle
underlying molecular self-assembly of proteins and peptides
towards designing novel biomimetic nanomaterials and their
potential applications in electronics, biotechnology, nanotechnology
and biomedicine.
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Mono-Substituted 4,4’-Dimethyl-2,2’-Bipyridine
Ligands at the Solid-Liquid Interface: Study of the Molecular
Organization
Stephanie Hoeppener, Veronica N. Marin and Ulrich
S. Schubert
Molecular organization has an important influence on
the performance of organic materials, i.e. solar cells, light
emitting diodes or sensors. 4,4’-Dimethyl-2,2’-bipyridines
have been identified as a promising candidate for such applications.
Therefore, high resolution STM investigations at the solid-liquid
interface have been conducted, to study the intermolecular
interaction of the bipyridine moieties. The results provide
inside in the self-organization behavior of 4,4’-dimethyl-2,2’-bipyridines
and the conclusions might help to understand the molecular
arrangement of this class of molecules and might serve, on
the long term, as a key to optimize their interaction with
respect to improved optoelectronic properties.
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Magnetic Driven Alginate Nanoparticles for Targeted Drug Delivery
Gianni Ciofani, Vittoria Raffa, Yosuke Obata, Arianna
Menciassi, Paolo Dario and Shinji Takeoka
The aim of this paper is to develop highly magnetized,
biodegradable and biocompatible, polymeric nanoparticles for
drug delivery in cell therapy. Alginate magnetic nanoparticles
are realized by an emulsion/reticulation technique, after
the dispersion of magnetite in an alginate solution. Such
nanoparticles are characterized in terms of external morphology
(FIB imaging), microstructure (TEM imaging), size distribution,
zeta potential, magnetic properties (SQUID analysis) and drug
release behaviour. Magnetization curves show the typical trend
of superparamagnetic materials. Important parameters, such
as magnetic permeability and magnetic momentum, are derived
by employing Langevin theory. Experimental results reveal
that a bi-exponential model fully describes the drug release.
Finally, in vitro experiments on NIH/3T3 cells are
carried out and demonstrate that our magnetic alginate nanoparticles
can effectively drive the drug delivery towards an external
magnetic field source.
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Endothelial Cell Response to Narrow Diameter Nylon Tubes Exhibiting
Internal Nanotopography
C. Berry, D. McCloy and S. Affrossman
The use of three dimensional scaffolds in tissue engineering
is well reported, as is the exploitation of nanotopography
to influence cell response. To date, due to fabrication limitations,
the combination of these two has experienced limited research.
This paper reports on the use of polymer demixing, a rapid
and cheap nanofabrication method, to create a defined nanotopography
in 0.5mm diameter nylon tubes. Results indicate that the resultant
nano-island topography reduced endothelial cell adhesion and
spreading, strongly influenced cell morphology, and appeared
to increase endocytic activity. The use of such constructs
that boast topographical cues have great potential in tissue
and cell engineering studies for future clinical use, in particular
with respect to conduits and stents.
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