Interest In Nanotechnology Research Articles

Nanostructured Surfaces of Dental Implants

The structural and functional fusion of the surface of the dental implant with the surrounding bone (osseointegration) is crucial for the short and long term outcome of the device. In recent years, the enhancement of bone formation at the bone-implant interface has been achieved through the modulation of osteoblasts adhesion and spreading, induced by structural modifications of the implant surface, particularly at the nanoscale level. In this context, traditional chemical and physical processes find new applications to achieve the best dental implant technology. This review provides an overview of the most common manufacture techniques and the related cells-surface interactions and modulation. A Medline and a hand search were conducted to identify studies concerning nanostructuration of implant surface and their related biological interaction. In this paper, we stressed the importance of the modifications on dental implant surfaces at the nanometric level. Nowadays, there is still little evidence of the long-term benefits of nanofeatures, as the promising results achieved in vitro and in animals have still to be confirmed in humans. However, the increasing interest in nanotechnology is undoubted and more research is going to be published in the coming years.

Single nanoparticle plasmonics

Interest in nanotechnology is driven by the unique and novel properties of nanoscale materials such as the strong interaction of metal particles with light, caused by localized surface plasmon resonances (LSPRs). In this perspective article we review and discuss prominent advantages and advances in single particle studies of plasmonic nanostructures. Common techniques and recent improvements in spatial and spectral resolution will first be outlined, covering both far-field and near-field phenomena. Then, new insight and information uniquely obtained from single particle approaches will be overviewed, including several fundamental studies of plasmonic behaviour, as well as applications using single particle tracking and chemical reaction monitoring. Finally, highly interdisciplinary future directions and experiments are discussed.

Biosynthesis, Antimicrobial and Cytotoxic Effect of Silver Nanoparticles Using a NovelNocardiopsissp. MBRC-1

The biosynthesis of nanoparticles has been proposed as a cost effective environmental friendly alternative to chemical and physical methods. Microbial synthesis of nanoparticles is under exploration due to wide biomedical applications, research interest in nanotechnology and microbial biotechnology. In the present study, an ecofriendly process for the synthesis of nanoparticles using a novel Nocardiopsis sp. MBRC-1 has been attempted. We used culture supernatant of Nocardiopsis sp. MBRC-1 for the simple and cost effective green synthesis of silver nanoparticles. The reduction of silver ions occurred when silver nitrate solution was treated with the Nocardiopsis sp. MBRC-1 culture supernatant at room temperature. The nanoparticles were characterized by UV-visible, TEM, FE-SEM, EDX, FTIR, and XRD spectroscopy. The nanoparticles exhibited an absorption peak around 420 nm, a characteristic surface plasmon resonance band of silver nanoparticles. They were spherical in shape with an average particle size of 45 ± 0.15 nm. The EDX analysis showed the presence of elemental silver signal in the synthesized nanoparticles. The FTIR analysis revealed that the protein component in the form of enzyme nitrate reductase produced by the isolate in the culture supernatant may be responsible for reduction and as capping agents. The XRD spectrum showed the characteristic Bragg peaks of 1 2 3, 2 0 4, 0 4 3, 1 4 4, and 3 1 1 facets of the face centered cubic silver nanoparticles and confirms that these nanoparticles are crystalline in nature. The prepared silver nanoparticles exhibited strong antimicrobial activity against bacteria and fungi. Cytotoxicity of biosynthesized AgNPs against in vitro human cervical cancer cell line (HeLa) showed a dose-response activity. IC50 value was found to be 200 μg/mL of AgNPs against HeLa cancer cells. Further studies are needed to elucidate the toxicity and the mechanism involved with antimicrobial and anticancer activity of the synthesized AgNPs as nanomedicine.

Biosynthesis, characterization and antibacterial activity of silver nanoparticles by aqueous Annona squamosa L. leaf extract at room temperature

Silver nanoparticles (AgNPs) have gained great interest in nanotechnology, biotechnology and medicine. The green synthesis of nanoparticles has received an increasing attention because of it’s maximize efficiency and minimize health and environmental hazards as compared to other conventional chemical synthesis. In this study, we reported biosynthesis of AgNPs by aqueous Annona squamosa L. leaf extract and its characterization by UV-visible spectroscopy (UV–vis), Field emission gun scanning electron microscopy (FEG-SEM), X-ray energy dispersive spectroscopy (EDX), Transmission electron microscopy (TEM), Selected-area electron diffraction (SAED) and Fourier transform infra-red spectroscopy (FTIR). The results indicated that AgNPs formed were spherical in shape with size ranging from 14 to 40 nm with an average diameter 28.47 nm. Furthermore, it was observed that the AgNPs exhibited an antibacterial activity against different Gram positive and Gram negative microorganisms. Our report confirmed that the ALE is a very good eco-friendly and nontoxic bioreductant for the synthesis of AgNPs and opens up further opportunities for fabrication of antibacterial drugs, medical devices and wound dressings.

Grazing-incidence small-angle X-ray scattering of soft and hard nanofabricated gratings

Grazing-incidence small-angle X-ray scattering (GISAXS) has been used to structurally characterize model hard and soft gratings of nanotechnological interest. The different gratings exhibit GISAXS patterns with characteristic features that can be associated with their level of order along the direction of periodicity and the length of the lines. Highly ordered gratings, made out of silicon by electron beam lithography, and those nanofabricated on spin-coated polymer films by nanoimprint lithography, exhibit characteristic semicircle-like GISAXS patterns with intensity spots periodically distributed on a semicircle whose radius is related to the incidence angle used. These gratings can be considered as one-dimensional crystalline lattices as provided by computer simulations. Less ordered polymer gratings prepared by the laser-induced periodic surface structuring method exhibit a GISAXS pattern characterized by periodic rod-like scattering maxima whose intensity decreases with increasing horizontal scattering angle. In this case the gratings can be considered as one-dimensional paracrystals. The transition from a rod-like to a semicircle-like GISAXS pattern has been simulated and attributed to the contribution of the form factor by changing the length of the line (ripple). A critical length value for the transition is located at around a few micrometres.

Assessment of DNA damage caused by locally produced hydroxyapatite-silica nanocomposite using Comet assay on human lung fibroblast cell line

The growing interest of nanotechnology in dentistry has sparked various applications of biomaterials in nanoscale to be developed. The aim of this study was to evaluate the genotoxicity effect of locally produced hydroxyapatite-silica nanocomposite (School of Dental Sciences, Universiti Sains Malaysia, Malaysia) using Comet assay on human lung fibroblast cell line, MRC-5. Extraction of this test material was prepared and the concentrations which produced IC10, IC25 and IC50 in cytotoxicity tests (MTT assay) were recorded. Three specific concentrations, 0.00005 g/mL, 0.0009 g/mL and 0.1 g/mL for IC10, 1C25 and IC50 respectively were further used to evaluate the genotoxicity effect along with concurrent positive (hydrogen peroxide) and negative (Eagle’s Minimum Essential Medium) controls. There was no significant difference in the tail moments between negative control and treatment groups (0.00005 g/mL). Dose-dependent relationship was observed, where significant difference was noticed in the tail moments between 0.0009 g/mL and 0.1 g/mL groups with that of the negative control. However, since the values were still less than 5, it can be considered as non-genotoxic. The tail moments between different concentrations of hydroxyapatite-silica nanocomposite and positive control differed significantly (P/0.05). This concludes that the locally produced HAsilica nanocomposite is non-genotoxic by Comet assay under the present test conditions.

Bioinspired synthesis of highly stabilized silver nanoparticles using Ocimum tenuiflorum leaf extract and their antibacterial activity

Biosynthesis of nanoparticles is under exploration due to wide biomedical applications and research interest in nanotechnology. We herein reports bioinspired synthesis of silver nanoparticles with the aid of novel, non toxic ecofriendly biological material namely Ocimum tenuiflorum leaf extract. It acts as reducing as well as stabilizing agent. An intense surface plasmon resonance band at ∼450nm in the UV–visible spectrum clearly reveals the formation of silver nanoparticles. The photoluminescence spectrum was recorded to study excitation and emission. TEM and PSD by dynamic light scattering studies showed that size of silver nanoparticles to be in range 25–40nm. Face centered cubic structure of silver nanoparticles are confirmed by SAED pattern. The charge on synthesized silver nanoparticles was determined by zeta potential. The colloidal solution of silver nanoparticles were found to exhibit high antibacterial activity against three different strains of bacteria Escherichia coli (Gram negative), Corney bacterium (gram positive), Bacillus substilus (spore forming).

Demonstration of Nanomachining With Focused Extreme Ultraviolet Laser Beams

A major challenge in laser machining of microstructures is that of extending the spatial domain to the smaller dimensions of interest in nanotechnology. We demonstrate the feasibility of directly machining nanoscale structures with a focused extreme ultraviolet (EUV) laser beam. Clean sub-200-nm-wide trenches (130-nm full width at half maximum) were ablated on polymethyl methacrylate photoresist by focusing the 46.9-nm wavelength beam from a Ne-like Ar capillary discharge tabletop laser with a Fresnel zone plate lens. Considering that clean 82-nm holes were also ablated using the same laser, it can be expected that focused EUV laser light will enable the machining of significantly smaller features.

Self-assembly of human amylin-derived peptides studied by atomic force microscopy and single molecule force spectroscopy

The self-assembly of peptides and proteins into amyloid fibrils of nanometric thickness and up to several micrometres in length, a phenomenon widely observed in biological systems, has recently aroused a growing interest in nanotechnology and nanomedicine. Here we have applied atomic force microscopy and single molecule force spectroscopy to study the amyloidogenesis of a peptide derived from human amylin and of its reverse sequence. The spontaneous formation of protofibrils and their orientation along well-defined directions on graphite and DMSO-coated graphite substrates make the studied peptides interesting candidates for nanotechnological applications. The measured binding forces between peptides correlate with the number of hydrogen bonds between individual peptides inside the fibril structure according to molecular dynamics simulations.

Nanodrug potential in cancer therapy: efficacy/toxicity studies in cancer cells

The interest of nanotechnology to find a more effective approach for drug delivery is growing fast. Nanoparticles as drug vehicles potentially improve the pharmacokinetic and pharmacodynamic properties of various types of drugs, and provide a tool to visualise molecules and tumour target cells that otherwise cannot be detected through conventional imaging. However, there are many aspects of nanoparticle formulation, characterisation and their effect on delivery of drugs and therapeutics that remain to be explored. This review summarises the main characteristics of nanoparticles for drug delivery in cancer treatment, and describes an experimental approach for evaluating efficacy and toxicity of nanocarriers in cancer cells.

Dynamics of ZnII Binding as a Key Feature in the Formation of Amyloid Fibrils by Aβ11-28

Supramolecular assembly of peptides and proteins into amyloid fibrils is of multifold interest, going from materials science to physiopathology. The binding of metal ions to amyloidogenic peptides is associated with several amyloid diseases, and amyloids with incorporated metal ions are of interest in nanotechnology. Understanding the mechanisms of amyloid formation and the role of metal ions can improve strategies toward the prevention of this process and enable potential applications in nanotechnology. Here, studies on Zn(II) binding to the amyloidogenic peptide Aβ11-28 are reported. Zn(II) modulates the Aβ11-28 aggregation, in terms of kinetics and fibril structures. Structural studies suggest that Aβ11-28 binds Zn(II) by amino acid residues Glu11 and His14 and that Zn(II) is rapidly exchanged between peptides. Structural and aggregation data indicate that Zn(II) binding induces the formation of the dimeric Zn(II)(1)(Aβ11-28)(2) species, which is the building block of fibrillar aggregates and explains why Zn(II) binding accelerates Aβ11-28 aggregation. Moreover, transient Zn(II) binding, even briefly, was enough to promote fibril formation, but the final structure resembled that of apo-Aβ11-28 amyloids. Also, seeding experiments, i.e., the addition of fibrillar Zn(II)(1)(Aβ11-28)(2) to the apo-Aβ11-28 peptide, induced aggregation but not propagation of the Zn(II)(1)(Aβ11-28)(2)-type fibrils. This can be explained by the dynamic Zn(II) binding between soluble and aggregated Aβ11-28. As a consequence, dynamic Zn(II) binding has a strong impact on the aggregation behavior of the Aβ11-28 peptide and might be a relevant and so far little regarded parameter in other systems of metal ions and amyloidogenic peptides.

LDI and ESI MS as well as low energy CID of a self‐assembling nanorod‐forming fullerene derivative

An amphiphatic fullerene derivative (8-(N-Methyl-Fullero-Pyrrolidinium-1-yl-chloride)-3,6-Dioxaoctan-1-Ammonium Chloride (MFPDAC)), which is of great interest in nanotechnology due to the fact that it forms self-assembling fullerenic nanorods, has been structurally characterized with emphasis to its purity and thermal treatment of a formed nanorod film (on a LDI target) by means of laser desorption/ionization (LDI) coupled with high-resolution curved field reflectron time-of-flight (TOF) mass spectrometry, and by low energy MS/MS as well as in-source fragmentation experiments applying an quadrupole ion trap (QIT) combined with a two-stage reflectron TOF analyzer. The interpretation of LDI results has been supplemented by ESI QIT MS(n) (n = 1-3), as well as high-resolution ESI reflectron TOF mass spectrometric experiments. Based on the experimental data obtained by both desorption/ionization techniques, various types of analyzers and sample treatments, we could completely characterize MFPDAC and further found out that the investigated sample was not entirely free of impurities. Furthermore, the envisaged loss of the derivative sidechain upon the heat treatment in vacuum of the self-assembled nanorod sample film on a metallic substrate could be successfully monitored by LDI MS.

Invitation to Gold 2012, Tokyo

The price of gold reached 1891.90 US dollars per ounce during August 2011, suggesting that gold has found a new prominence in global financial markets and economics. An increasing number of people are currently protecting their capital in an asset that offers a safe store of value to today's investor. At the same time, the industrial applications of gold, largely centered on electronics (bonding wires, electroplating, etc.), have been growing and currently occupy around 12% of total gold demand. So a new gold rush is underway at the cutting edge of nanoscience and -technology research. A typical example is catalysis by gold. For over a century, gold in bulk form had been considered too noble to work as a catalyst. However, it has recently been proved that gold exhibits surprisingly high catalytic activity for many reactions when deposited as nanoparticles on base metal oxides, carbons, and polymers. At the same time, gold colloids of different morphology are attracting growing interest owing to their special surface plasmonics; applications in DNA diagnosis, health care, and new paints are on the horizon. Coulomb blockade by quantum dots may present a new topic in electronics. Self-assembled monolayers on a substrate of gold are also an interesting area of research which functionalizes solid surfaces leading to catalysis, electrodes, and optoelectronics. These are just a part of the expanding science and technology of gold. Plenty of exciting discoveries and achievements are still emerging in other areas too, for example unexpected magnetism in gold nanostructures. To discuss and debate this rapid growth of gold science and technology, the Gold 2012 conference will be held at one of the biggest terminals in the center of Tokyo, Shinjuku. Participants will enjoy a magnificent view from the 42nd and 43rd floors of the conference venue, the Keio Plaza Hotel. You are cordially invited to join us for this 6th Gold Conference, the first in Asia, after Heidelberg (2009), Limerick (2006), Vancouver (2003), Cape Town (2001), and Hanau (1996). Japan was once called the island of gold, Zipang, and it is now moving to the island to nanogold. Please join us at Gold 2012 in Tokyo to discuss mutual interests in nanotechnology, chemistry, catalysis, and nanomaterials of gold and its applications (www.gold2012.org) M. Haruta Chairman of the GOLD 2012 Organising Committee

Classroom modules for nanotechnology undergraduate education: development, implementation and evaluation

In order to address the challenges and restrictions given by a traditional classroom lecture environment, the top-down and bottom-up nanotechnology teaching modules were developed, implemented and evaluated. Then based on the hypothesis that instructors could further develop students’ interest in this emerging area through the introduction of the teaching modules and a career module, an early stage evaluation of the effectiveness of the modules in selected engineering courses was conducted. The data suggested that adoption of modular lectures in regular engineering courses influenced attitude towards nanotechnology – overall, the teaching modules did a better job of piquing student's interest (albeit in the short term) in the subject, but there were also positive gains in interest in nanotechnology as a career. There was some evidence that the hands-on demonstration teaching modules with visual elements and the career module were more effective than traditional lecture presentations in the classroom.

Nanoparticles: their potential use in antibacterial photodynamic therapy

Photodynamic therapy (PDT) has been proposed as a new technique to inactivate microorganisms as it does not lead to the selection of mutant resistant strains; a clear benefit compared to antibiotic treatment. PDT has also attracted the interest of nanotechnology as the effectiveness of the treatment can be greatly enhanced by the use of nanoparticles. In the last decade, different approaches to the combination of nanoparticles and PDT have been investigated in relation to the antimicrobial applications of the technique. One use of the nanoparticles is to improve the delivery of photosensitiser to the bacteria; others use the nanoparticles to improve the inactivation kinetics. A different approach utilises nanoparticles as a photosensitiser. In this review these diverse types of interactions will be described.

Nanocarriers for Transmucosal Vaccine Delivery

Immunization has been realized as one of the most cost effective methods of controlling microbial infections. Currently, the most widely employed means of vaccine delivery includes intramuscular injection which is effective against pathogens invading via the systemic route. The antibody titers do not extend to mucosal or serosal sites which are also the portals of entry for invading pathogens. Mucosal means of delivery comes as viable alternatives. The oral route for mucosal vaccination has not been successful in presenting an- tigens to the body. Acidic environment and inactivating enzymes of the GI tract degrade the antigen before it is presented to the M-cells of Peyer's patches. Nanocarrier based vaccines however, can help to overcome the problems associated with mucosal delivery. These car- riers have shown to improve the bioavailability, act as adjuvant to provoke a stronger immune response while being targeted to associated tissues, leading to improved success of vaccination which inculcates interest of nanotechnology in vaccination. This review encompasses a wide range of nanocarriers that have been of interest.

Plant extract mediated synthesis of silver and gold nanoparticles and its antibacterial activity against clinically isolated pathogens

Biosynthesis of nanoparticles is under exploration is due to wide biomedical applications and research interest in nanotechnology. Bioreduction of silver nitrate (AgNO(3)) and chloroauric acid (HAuCl(4)) for the synthesis of silver and gold nanoparticles respectively with the plant extract, Mentha piperita (Lamiaceae). The plant extract is mixed with AgNO(3) and HAuCl(2), incubated and studied synthesis of nanoparticles using UV-Vis spectroscopy. The nanoparticles were characterized by FTIR, SEM equipped with EDS. The silver nanoparticles synthesized were generally found to be spherical in shape with 90 nm, whereas the synthesized gold nanoparticles were found to be 150 nm. The results showed that the leaf extract of menthol is very good bioreductant for the synthesis of silver and gold nanoparticles and synthesized nanoparticles active against clinically isolated human pathogens, Staphylococcus aureus and Escherichia coli.

나노물질의 측정전략의 주요 쟁점

The growing interest in nanotechnology has resulted in increasing concern and a number of published environmental and workplace measurements for assessing occupational exposure to engineered nanomaterials. However, the amount of previous exposure data remains limited. Furthermore the data available was collected with extensive variation in terms of exposure measurement strategy, which limits the ability to pool the data in the future. In response, this paper reviewed several pertinent issues related to exposure measurement strategy to suggest a harmonized measurement strategy which would make exposure data more useful in the future, e.g. correlation between exposure metrics, relationship between activity and exposure, task-based or shift-based assessment, background concentration, limitation of personal exposure monitoring and other determinants of exposure/modeling. An improved sampling strategy for nanomaterial exposure assessment should be considered in order to maximize the use of the data from various real time monitoring instruments.

Researcher Views About Funding Sources and Conflicts of Interest in Nanotechnology

Dependence in nanotechnology on external funding and academic-industry relationships has led to questions concerning its influence on research directions, as well as the potential for conflicts of interest to arise and impact scientific integrity and public trust. This study uses a survey of 193 nanotechnology industry and academic researchers to explore whether they share similar concerns. Although these concerns are not unique to nanotechnology, its emerging nature and the prominence of industry funding lend credence to understanding its researchers' views, as these researchers are shaping the norms and direction of the field. The results of the survey show general agreement that funding sources are influencing research directions in nanotechnology; many respondents saw this influence in their own work as well as other researchers' work. Respondents also agreed that funding considerations were likely to influence whether researchers shared their results. Irrespective of their institutional affiliation or funding status, twice as many researchers as not considered financial conflicts of interest a cause for concern, and three times as many respondents as not disagreed financial conflicts of interest in nanotechnology were uncommon. Only a third was satisfied with the way that conflicts of interest are currently managed and believed current procedures would protect the integrity of nanotechnology research. The results also found differences in views depending on researchers' institutional affiliation and funding status.

Study of Multiferroic Materials at Nano-Scale

With the growing interest in nanotechnology, the multifunctional materials are being imaged with much advanced precision microscopes. Difference in properties at bulk and nano-level has provided new insight and direction to the researchers to meet the ever-increasing demand of smaller and more efficient devices. This paper reports a study of the polar regions, ferroelectric domains and characterization on different sample surfaces of interest. The Scanning Probe Microscope has been used in its contact mode to obtain the nano-scale surface images of some important multifunctional ferroics such as Lead Potassium Niobate, Bismuth Titanate and Gadolinium Molybdate. The piezoresponse and ferroelectric properties have been the primary area of concentration. The study shows the interesting ferroelectric domain structure on various pristine sample surfaces.