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Current
Nanoscience
ISSN: 1573-4137
Current Nanoscience
Volume 4, Number 1, February 2008
Contents
Magnetic Nanoparticles for Cancer Therapy
Pp. 1-16
G.F. Goya, V. Grazú, and M.R. Ibarra
[Abstract]
Nanoprobes for Medical Diagnosis: Current Status
of Nanotechnology in Molecular Imaging Pp. 17-29
Jiang He, Henry F.VanBrocklin, Benjamin L. Franc, Youngho
Seo and Ella Fung Jones
[Abstract]
Solid Lipid Nanoparticles (SLNs) as a Rising
Tool in Drug Delivery Science: One Step Up in Nanotechnology
Pp. 30-44
Shivani Rai, Rishi Paliwal, Prem N. Gupta, Kapil Khatri,
Amit K. Goyal, Bhuvaneshwar Vaidya and S.P. Vyas
[Abstract]
Photoenergy Conversion System Based on the Photosynthesis
Dyes Conjugated Nanoparticle Pp. 45-52
Yutaka Amao
[Abstract]
Formulation of Nanosuspensions of Albendazole
for Oral Administration Pp. 53-58
Mittapalli Pavan Kumar, Yamasani Madhusudan Rao and Shashank
Apte
[Abstract]
Studies on the Drug-Loading Mechanism of Polybutylcyanocrylate
Nanoparticle and its Stability of Thermodynamics
Pp. 59-61
Zhang Xue-Nong, Gong Jing-Hong, Tang Li-Hua and Zhang
Qiang
[Abstract]
Molecularly-Resolved Bioelectronics
Pp. 62-70
Jason Davis, Ben Peters, Wang Xi and Daniel Axford
[Abstract]
Organic Nano-Compartments as Biomimetic Reactors
and Protocells Pp. 71-87
P.-A. Monnard, M.S. DeClue and H.-J. Ziock
[Abstract]
Luminescence Stability of the Silica Encapsulated
CdSe Quantum Dots Pp. 88-91
Xingping Zhou, Xiaqin Wang, Fuxian Liu, Zhilong Chen and
Atsuo Kasuya
[Abstract]
Optically Active Gold Nanoclusters Pp.
92-97
Hiroshi Yao
[Abstract]
Complexing Energies and Angular Translation of
Small Carbon Nanotube-Noble Gas Clusters Pp. 98-100
Amirhasan Nourbakhsh
[Abstract]
Physicochemical Characterization of Nano- and
Microparticles Pp. 101-107
Leena Peltonen and Jouni Hirvonen
[Abstract]
Simulating the XOR Gates Based on the Induced
Hairpin Formation Pp. 108-110
Wenbin Liu, Xiangou Zhu, Xianghong Wang, Zhixiang Yin
and Shudong Wang
[Abstract]
Developing a New Generation of Bone Cements With
Nanotechnology Pp. 111-118
Peishan Liu-Snyder and Thomas J. Webster
[Abstract]
Abstracts
[Back to top]
Magnetic Nanoparticles for Cancer Therapy
G.F. Goya, V. Grazú, and M.R. Ibarra
Today, technologies based on magnetic nanoparticles (MNPs)
are routinely applied to biological systems with diagnostic
or therapeutic purposes. The paradigmatic example is the magnetic
resonance imaging (MRI), a technique that uses the magnetic
moments of MNPs as a disturbance of the proton resonance to
obtain images. Similarly, magnetic fluid hyperthermia (MFH)
uses MNPs as heat generators to induce localized cell death.
The physical basis of these techniques relies on the interaction
with external magnetic fields, and therefore the magnetic
moment of the particles has to be maximized for these applications.
Targeted drug-delivery based on ‘smart’ nanoparticles
is the next step towards more efficient oncologic therapies,
by delivering a minimal dose of drug only to the vicinity
of the target. Current improvements in this fields relay on
a) particle functionalization with specific ligands for targeting
cell membrane receptors and b) loading MNPs onto cells (e.g.,
dendritic cells, T-cells, macrophages) having an active role
in tumor grow. Here we review the current state of research
on applications of magnetic carriers for cancer therapy, discussing
the advances and drawbacks of both passive and targeted delivery
of MNPs. The most promising strategies for targeted delivery
of MNPs are analyzed, evaluating the expected impact on clinical
MRI and MFH protocols.
[Back to top]
Nanoprobes for Medical Diagnosis: Current Status of Nanotechnology
in Molecular Imaging
Jiang He, Henry F.VanBrocklin, Benjamin L. Franc, Youngho
Seo and Ella Fung Jones
Molecular imaging has emerged as a powerful tool to visualize
molecular events of an underlying disease, sometimes prior
to its downstream manifestation. This presents a whole new
paradigm disease diagnosis and monitor treatment. Nanotechnology
is another rapidly growing field that offers new materials
with unique physical and chemical properties that may find
broad application in biomedical research. The merging of nanotechnology
with molecular imaging provides a versatile platform for novel
design of nano-probes that will have tremendous potential
to enhance the sensitivity, specificity, and signaling capabilities
of various biomarkers in human diseases. In this review, the
general construct and key characteristics of nanoprobes in
the context of molecular imaging are highlighted. The various
designs of nanoprobes based on their targeting mechanisms,
strategies for contrast enhancement, multi-modality imaging
and imaging/therapy hybrid systems are outlined along with
a discussion on the current status of imaging equipment design.
Additionally, the potential challenges for adapting nanoprobes
for molecular imaging including toxicity, biodistribution/pharmacokinetics,
and synthetic feasibility are addressed.
[Back to top]
Solid Lipid Nanoparticles (SLNs) as a Rising Tool in Drug
Delivery Science: One Step Up in Nanotechnology
Shivani Rai, Rishi Paliwal, Prem N. Gupta, Kapil Khatri,
Amit K. Goyal, Bhuvaneshwar Vaidya and S.P. Vyas
Colloid science has now been reframed in advance form
as nanotechnology. Novel nanoparticulate carrier systems could
make an important impact on clinical practice, not only in
the field of targeted drug delivery but also for the delivery
of diagnostic agents, gene therapy and vaccine delivery as
well. Polymer based nanoparticles are full of numerous advantages
in delivery science but at the same time they suffer from
toxicity considerations and problems in industrial scale up
of the formulations. Lipid based carrier systems i.e. emulsions,
liposomes etc. have been tried to solve such problems related
to the delivery technology. Currently lipid-based nanoparticles
gained much interest as they combine both the technology of
lipid sciences and nanosciences, and hence may be better alternative
carriers. Many aspects related to the development of solid
lipid nanoparticles (SLNs) like production technology, effect
of process parameters, selection of ingredients and route
of delivery are important for the industrial applications
of nanoscience. In the present review a detail discussion
of methods of production of solid lipid nanoparticles, influence
of ingredients of composition on product quality, therapeutic
moiety effect, characterization parameters and effects of
sterilization have been focused. Role of solid lipid nanoparticles
for controlled and targeted drug delivery, utility as a novel
transfection agent and their potential as adjuvant for vaccine
delivery are summed up in addition. Clinical therapeutics
of SLNs in terms of advantages and limitations of various
routes of delivery of SLNs has also been explored for the
further advancement of practical applications of solid lipid
nanoparticles.
[Back to top]
Photoenergy Conversion System Based on the Photosynthesis
Dyes Conjugated Nanoparticle
Yutaka Amao
The solar energy conversion system based on photosynthesis
is promising as alternative energy invention technology of
the future. In this review, the photoenergy conversion system
based on the photosensitization of major photosynthesis dye
pigment molecule, chlorophyll immobilized onto titanium dioxide
or assembled into surfactant micellar system are introduced.
One is the photoinduced hydrogen production system with the
system containing an electron donor reagent, an electron carrier
reagent, hydrogen producing catalyst and chlorophyll molecule
assembled in surfactant micellar system. The other one is
the photovoltaic conversion system based on the chlorophyll
or chlorophyll derivative molecules immobilized onto nanocrystalline
TiO2 film electrode.
[Back to top]
Formulation of Nanosuspensions of Albendazole for Oral Administration
Mittapalli Pavan Kumar, Yamasani Madhusudan Rao and Shashank
Apte
Poorly water-soluble compounds like albendazole with
dissolution limited bioavailability need novel approaches
for enhancement of bioavailability and therapeutic efficacy.
The use of nanosuspension approach offers an opportunity to
address the issues associated with BCS class II molecules.
High pressure homogenization technique can be employed to
produce drug nanocrystals with a number of advantages in comparison
to other techniques such as nanoprecipitation, sonication,
milling and high speed homogenization. The present study shows
the feasibility of formulating a stable formulation of albendazole
with minimum particle size through high pressure homogenization
technique. To point out the influence and importance of identifying
right stabilizer (s) and process parameters the studies such
as influence of number of homogenizing cycles on particle
size, sequence of mixing of ingredients on the physical characteristics
of nanosuspensions and desorption studies was done. Selected
nanosuspension formulations containing different stabilizers
were lyophilized to convert into solid dosage forms. These
studies had indicated that the aqueous dispersion of drug
nanoparticles could be converted into stable solid dosage
forms with out affecting the size on reconstitution.
[Back to top]
Studies on the Drug-Loading Mechanism of Polybutylcyanocrylate
Nanoparticle and its Stability of Thermodynamics
Zhang Xue-Nong, Gong Jing-Hong, Tang Li-Hua and Zhang
Qiang
Aim of this paper is to study the load-drug mechanism
of polybutylcyanocrylate nanoparticles and the physical stability
of albendazole-polybutylcyanocrylate nanoparticle (ABZ-PBCA-NP).
The adsorption mechanism between albendazole with polybutylcyanocrylate
nanoparticle in different phosphate buffer solution (PBS)
were investigated with isothermadsorption method. The constants
of stability constants of albendazole-loading nanoparticles
were predicted by determined the conductance rate of nanoparticles
colloid under predetermined temperature in interval time.
At the same time, several stabilizer including polyvinyl pyrrolidone
(PVP), carboxymethylcellulose sodium (CMC-Na) and hydroxoy-propyl
methyl cellulose (HPMC) was screen for improving stability
and fluidity of nanoparticle suspension. The results showed
that the mechanism of drug-load in nanoparticle was fitted
the Langmuir equation. The conductance rate indicated that
load-drug nanoparticle in suspension was unstability due to
nature aggregation tendency and improved by reinforced with
4% PVP in solution.
[Back to top]
Molecularly-Resolved Bioelectronics
Jason Davis, Ben Peters, Wang Xi and Daniel Axford
The field of molecular electronics measures the unique
properties of individual molecular species in conductor-molecule-conductor
junctions. We present here a brief review of molecular electronics
as applied to biomolecules, with specific emphasis on the
use of scanning probe technology in the assaying of biological
molecular electronics. Three case studies from recent work
within our group are described; two complimentary investigations
of the redox-active yeast iso-1-cytochrome c and
one of the large iron storage protein ferritin. The strengths
and challenges of the use of scanning probe technology for
the purpose of molecular electronics are also outlined. Particular
emphasis is given to the potential of gating conductance and
the perturbative effects of analysis.
[Back to top]
Organic Nano-Compartments as Biomimetic Reactors and Protocells
P.-A. Monnard, M.S. DeClue and H.-J. Ziock
In recent years, nanoscale self-assembled structures
have attracted ever increasing attention because of their
potential to act as molecular templates for the synthesis
of novel materials, delivery vehicles for therapeutic agents,
and compartments defined at the molecular level that provide
environmental conditions conducive to specific chemical reactions.
In this review, we will focus mostly on this latter application.
Amphiphiles that self-assemble to yield nano-compartments
such as micelles, reverse-micelles and liposomes, have been
used to build nanoscale reactors that can effect chemical
reactions through spatial co-localization of the reacting
species. The reacting species may include the compartment
building amphiphiles themselves. These nano-compartments provide
not only the conditions for the reaction to occur, but also
allow the buildup of complex reaction networks by retaining
primary reaction products which may in turn be capable of
additional reactions. Ultimately, such complex systems could
also serve as starting points for minimal artificial cells,
i.e. protocells which would be highly simplified versions
of biological cells and which might be engineered for specific
tasks related to therapeutic and diagnostic applications.
We will report on advances in the design of these chemical
self-assembled systems and the challenges that still lie ahead.
[Back to top]
Luminescence Stability of the Silica Encapsulated CdSe Quantum
Dots
Xingping Zhou, Xiaqin Wang, Fuxian Liu, Zhilong Chen and
Atsuo Kasuya
Silica encapsulated CdSe quantum dots (QDs) with a relatively
strong photoluminescence were prepared using 3-mercaptopropyl
trimethoxysilane by Stöber method at room temperature.
The effect of pH of the physiological saline on the photoluminescence
was investigated while the nanocomposites were dispersed in
it. The results show a comparatively high stability of the
luminescence. The thermal stability of the photoluminescence
of the composite nanoparticles was also studied. After annealing
at 60°C for 2 h, the photoluminescence was kept constant.
Then, after annealing at 200°C for 2 h, the photoluminescence
was promoted by over 10 times with a marked blue-shifted emission.
In addition, the stabilization of the core-shell structured
composites against the intense illumination was investigated
through the transmission electron microscopy (TEM) observation
and the luminescence measurement.
[Back to top]
Optically Active Gold Nanoclusters
Hiroshi Yao
In recent years, increasing attention has been paid for
the construction of optically active nanomaterials. In particular,
monolayer-protected gold nanoclusters are attractive for such
systems. To date, optically active gold nanoclusters have
been prepared by using chiral adsorbates or surface modifiers.
In general, two major explanations have been proposed to interpret
the optical activity: The first assumes a chiral core as a
result of lattice distortion caused by the adsorbate. The
other involves an achiral core with chirality induced by a
chiral adsorption pattern or by dissymmetric fields (vicinal
effect) from the chiral adsorbates. This mini-review gives
an outline of the syntheses and chiroptical properties of
the chiral monolayer-protected gold nanoclusters on the basis
of our recent work as well as the other groups’ studies.
[Back to top]
Complexing Energies and Angular Translation of Small Carbon
Nanotube-Noble Gas Clusters
Amirhasan Nourbakhsh
The structures and the nonbonded intermolecular interactions
of the endohedral and exohedral 4Å-diameter carbon nanotube-noble
gas clusters, NG@CNT (NG = He, Ne, Ar, Kr, and Xe) are evaluated
and calculated using the atom-atom potential method. The complexing
energies are determined with a Lennard-Jones model. Complexing
energies are significantly dependent on azimuthal angle. Endohedral
complexes are more stable; consequently, noble gases can be
accommodated into 4 Å diameter carbon nanotubes. While
slightly larger atoms Ar, Kr, and Xe atoms are more stable.
[Back to top]
Physicochemical Characterization of Nano- and Microparticles
Leena Peltonen and Jouni Hirvonen
Formulation studies of nano- and microparticles are a
rapidly developing area in pharmaceutical sciences. Bioavailability
of poorly water-soluble drugs may be increased by administrating
them as nanoparticle formulations. Drug targeting to specific
body sites has also been studied intensively (e.g. cancer
chemotherapy). In order to ensure the repeatability of the
formulation processes and the efficacy/stability of the formed
particles, thorough characterization of the formulations and
particles is crucial. The importance of analytical techniques
and even during the process analysis has been highlighted
by drug authorities (e.g. FDA) with the PAT approach. Minor
deviations, e.g., in particle size/shape, surface charge or
aggregation tendency, may play a significant role in their
behavior in the body. The very small size of the nanoparticles
imposes extra demands for the characterization techniques.
In this review, the most commonly used and most important
analysis methods to characterize the micro and nanoparticles
are discussed with critical view on the applicability and
limitations of the methodologies. Some techniques are well
known for the researchers in the small particle area (e.g.
microscopic techniques, thermal analysis, zeta potential,
dissolution rate), but also more rarely used and new techniques
(e.g. surface tension/pressure measurements, spectroscopic
methods) are taken into account.
[Back to top]
Simulating the XOR Gates Based on the Induced Hairpin Formation
Wenbin Liu, Xiangou Zhu, Xianghong Wang, Zhixiang Yin
and Shudong Wang
The hairpin structure of DNA molecules have been widely
employed for a variety of biosensors and nanoscale molecular
assembly applications. For example, the commonly known molecular
beacons can report the presence of specific nucleic acids
in homogeneous solutions with high accuracy. Recently, Smith
et al. proposed to induce hairpin formation through
the sequence-specific binding of a small-molecule ligand G-G
mismatch. Not only did this make the control of the hairpin
formation flexible, but more important the induced hairpin
still keeps a high sensitivity to specific hybridization.
In this paper, we simulate the working process of logical
XOR gates based on induced hairpin formation.
[Back to top]
Developing a New Generation of Bone Cements With Nanotechnology
Peishan Liu-Snyder and Thomas J. Webster
Around 500,000 people have total joint (including hip
and knee) replacement surgeries each year. However, current
joint implants last only 10 to 15 years before failing. Undoubtly
because of this, many patients have to go through a revision
surgery due to the failure of bone implants. The main reason
for implant failure is aseptic loosening of the implant from
juxtaposed bone. In this light, polymethyl methacrylate (PMMA)
has been used widely in orthopedics to improve the bonding
between the implant and bone. In total hip replacement procedures,
PMMA cement is located at the bone-implant interface and plays
an important role in inhibiting the aseptic loosening processes.
PMMA cement is associated with several drawbacks that limit
its efficacy (such as strong exothermic reactions, weak radiopacity
and poor fatigue strength; all leading to insufficient bonding
to bone). With an expectation of increased revision surgeries
and patients receiving orthopedic implants in the coming years,
the emphasis of joint replacement research needs to be focused
on improving the mechanical and biocompatibility properties
of bone cements. As nanotechnology has been extensively used
to improve mechanical and surface properties of implant materials,
it certainly provides a unique opportunity to modify the material
properties of currently used bone cements in a more precise
manner. This article reviews nanotechnology-based advancements
made to PMMA cement and bioactive cements (Bis-GMA cement
and calcium phosphate cement (CPC)). A discussion of accomplishments,
potentials and challenges for the application of nanotechnology
in bone cements then follows.
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