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Find video protocols related to scientific articles indexed in Pubmed.
Plasmon-induced photoluminescence immunoassay for tuberculosis monitoring using gold nanoparticles decorated graphene.
ACS Appl Mater Interfaces
PUBLISHED: 11-15-2014
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Metal-nanoparticle-functionalized graphene, in particular, graphene sheets containing Au nanoparticles (Au NPs), have generated considerable interest due to their unique optical and electrical characteristics. In this study, we successfully produced graphene sheets decorated with Au NPs (AuGrp) using phytochemicals as reducing agents. During this reaction, Au ions intercalated into the layered graphene flakes and were then reduced into NPs, exfoliating the graphene sheets. The physicochemical properties of the AuGrp nanocomposites were characterized, and the exfoliation process was investigated using a molecular dynamics simulation of Au NPs between graphene sheets. Our proposed technique is advantageous because the phytochemicals are mild reducing agents that preserve the graphene structure during exfoliation and NP decoration. The dispersity of the NPs on the graphene sheets was drastically improved due to the use of metal-ions intercalation. Moreover, the electrical conductivity was 6-30 times higher than that of bare graphene and reduced graphene oxide. Using antibody (Ab) modified AuGrp sheets and quantum dots, a plasmonic-induced photoluminescence immunoassay of tuberculosis (TB) antigen (aG) CFP-10 was demonstrated for a potential application of these materials. The enhancement of photoluminescence (PL) response was monitored depending on the various TB aG concentrations from 5.1 pg/mL to 51 ?g/mL, and the detection limit for CFP-10 was 4.5 pg/mL. Furthermore, the selectivity was demonstrated with Ag85 as the other TB aG, and PL enhancement was not observed in this case. Therefore, AuGrp based immunoassay showed the potential for biosensor application.
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Cytotoxicity and Gene Expression in Sarcoma 180 Cells in Response to Spiky Magnetoplasmonic Supraparticles.
ACS Appl Mater Interfaces
PUBLISHED: 11-05-2014
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Multifunctional nanoparticles (NPs) have been designed for a variety of cell imaging and therapeutic applications, and the study of their cellular interactions is crucial to the development of more efficient biomedical applications. Among current nanomaterials, concave core-shell NPs with complex angled geometries are attractive owing to their unique shape-dependent optical and physical properties as well as different tendency for cell interaction. In this study, we investigated the morphology effect of spiky gold-coated iron oxide supraparticles (Fe3O4@Au SPs) on cytotoxicity and global gene expression in sarcoma 180 cells. Cells treated for 7 days with spiky supraparticles (SPs) at concentrations up to 50 ?g/mL showed >90% viability, indicating that these NPs were nontoxic. To shed light on the differences in cytotoxicity, we monitored the expression of 33?315 genes using microarray analysis of SP-treated cells. The 171 up-regulated genes and 181 down-regulated genes in spiky SP-treated cells included Il1b, Spp1, Il18, Rbp4, and Il11ra1, where these genes are mainly involved in cell proliferation, differentiation, and apoptosis. These results suggested that the spiky Fe3O4@Au SPs can induce noncytotoxicity and gene expression in tumor cells, which may be a promising cornerstone on which to base related research such as cyto-/genotoxicology of nanomaterials or the design of nanoscale drug carriers.
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A plasmon-assisted fluoro-immunoassay using gold nanoparticle-decorated carbon nanotubes for monitoring the influenza virus.
Biosens Bioelectron
PUBLISHED: 08-01-2014
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A plasmon-assisted fluoro-immunoassay (PAFI) was developed for the detection of the influenza virus by using Au nanoparticle (Au NP)-decorated carbon nanotubes (AuCNTs) that were synthesized using phytochemical composites at room temperature in deionized water. Specific antibodies (Abs) against the influenza virus were conjugated onto the surface of AuCNTs and cadmium telluride quantum dots (QDs), which had a photoluminescence intensity that varied as a function of virus concentration and a detection limit of 0.1pg/mL for all three types of influenza viruses examined. The clinically isolated influenza viruses (A/Yokohama/110/2009 (H3N2)) were detected in the range of 50-10,000PFU/mL, with a detection limit of 50PFU/mL. From a series of proof-of-concept and clinical experiments, the developed PAFI biosensing system provided robust signal production and enhancement, as well as an excellent selectivity and sensitivity for influenza viruses. This nanoparticle-based technique could be potentially developed as an efficient detection platform for the influenza virus.
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Predictive factors of telemedicine service acceptance and behavioral intention of physicians.
Int J Med Inform
PUBLISHED: 05-23-2014
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Despite the proliferation of telemedicine technology, telemedicine service acceptance has been slow in actual healthcare settings. The purpose of this research is to develop a theoretical model for explaining the predictive factors influencing physicians' willingness to use telemedicine technology to provide healthcare services.
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Phase-pure FeSe(x) (x = 1, 2) nanoparticles with one- and two-photon luminescence.
J. Am. Chem. Soc.
PUBLISHED: 05-12-2014
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Iron chalcogenides hold considerable promise for energy conversion and biomedical applications. Realization of this promise has been hindered by the lack of control over the crystallinity and nanoscale organization of iron chalcogenide films. High-quality nanoparticles (NPs) from these semiconductors will afford further studies of photophysical processes in them. Phase-pure NPs from these semiconductors can also serve as building blocks for mesoscale iron chalcogenide assemblies. Herein we report a synthetic method for FeSe(x) (x = 1, 2) NPs with a diameter of ca. 30 nm that satisfy these needs. The high crystallinity of the individual NPs was confirmed by transmission electron microscopy (TEM) and energy-dispersive X-ray analysis. TEM tomography images suggest pucklike NP shapes that can be rationalized by bond relaxation at the NP edges, as demonstrated in large-scale atomic models. The prepared FeSe(x) NPs display strong photoluminescence with a quantum yield of 20%, which was previously unattainable for iron chalcogenides. Moreover, they also show strong off-resonant luminescence due to two-photon absorption, which should be valuable for biological applications.
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Enhancement of primary neuronal cell proliferation using printing-transferred carbon nanotube sheets.
J Biomed Mater Res A
PUBLISHED: 04-14-2014
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Artificial nerve guidance conduits (aNGCs) prepared from polymer scaffolds and carbon nanotubes (CNTs) possess unique chemical and physical properties, and have been widely used in preclinical trials to promote neuronal differentiation and growth. However, there have been only a few reports on the clinical applicability of CNT sheets for proliferation of primary neuronal cells due to safety concerns. The present study assesses the ability and potential applicability of multiwalled CNTs (MWNTs) composited with polydimethylsiloxane (PDMS) sheets to promote and enhance the proliferation of primary neuronal cells. In this study, the aqueous MWNT dispersion was filtered, and the PDMS/MWNT sheets were prepared using a simple printing transfer method. Characterization of PDMS/MWNT sheets demonstrated their unique physical properties such as superior mechanical strength and electroconductivity when compared with PDMS sheets. The effect of the PDMS/MWNT sheets on the neural cell proliferation and cytotoxicity was evaluated using MTT and alamar blue assays. Our results indicate the viability and proliferation of primary neuronal cells and Schwann cells in PDMS/MWNT sheets increased over twice when compared with a noncoated dish that is not usual in the primary neuronal cell growth control (p?
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Metal enhanced fluorescence on nanoporous gold leaf-based assay platform for virus detection.
Biosens Bioelectron
PUBLISHED: 01-26-2014
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In the present study, a rapid, sensitive and quantitative detection of influenza A virus targeting hemagglutinin (HA) was developed using hybrid structure of quantum dots (QDs) and nanoporous gold leaf (NPGL). NPGL film was prepared by dealloying bimetallic film where its surface morphology and roughness were fairly controlled. Anti-influenza A virus HA antibody (ab66189) was bound with NPGL and amine (-NH2) terminated QDs. These biofunctionalized NPGL and QDs formed a complex with the influenza virus A/Beijing/262/95 (H1N1) and the photoluminescence (PL) intensities of QDs were linearly correlated with the concentrations of the virus up to 1ng/mL while no PL was observed in the absence of the virus, or in bovine serum albumin (BSA, 1µg/mL) alone. In addition, it was demonstrated that this assay detected successfully influenza virus A/Yokohama/110/2009 (H3N2) that is isolated from a clinical sample, at a concentration of ca. 50 plaque forming units (PFU)/mL. This detection limit is 2-order more sensitive than a commercially available rapid influenza diagnostic test. From these results, the proposed assay may offer a new strategy to monitor influenza virus for public health.
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Non-toxic nanoparticles from phytochemicals: preparation and biomedical application.
Bioprocess Biosyst Eng
PUBLISHED: 10-02-2013
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Nanoparticles (NPs) have various applications in biomedicine and drug delivery carriers and also are widely used in cosmetics. However, the preparation of biocompatible and non-toxic nanomaterials is a very important issue as most of the starting materials are synthesized using toxic chemical reagents. This review introduces the preparation of biocompatible NPs in a range of their concentrations using phytochemicals for biomedicine and biotechnology. Phytochemicals are natural products that are extracted from plants, vegetables, and fruits. Phytochemicals serve as reducing agents and stabilizers during NP synthesis to convert metal ions to metal NPs in water. Possible applications of such nanomaterials in biomedical sciences are also described in this review.
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Guided bone regeneration using a flexible hydroxyapatite patch.
J Biomed Nanotechnol
PUBLISHED: 09-25-2013
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Guided bone regeneration (GBR) is a new method of promoting new bone formation by blocking the proliferation of regenerated connective tissue or providing additional interventions such as direct drug delivery and mechanical support. This in vivo study of bone regeneration in radius compound fractures in rabbits was conducted using a highly flexible scaffold of nanoscale hydroxyapatite (nHAp)/chitosan, termed a "bone patch". A solidification-assisted compression (SAC) method was utilized to fabricate the bone patch, and its in vivo cytotoxicity, bio-absorption, and bone regeneration capacity were evaluated. Four weeks after implantation, new bone formation with abundant active osteoblasts and incompleted degradation of chitosan in the patch were observed without any regeneration of connective tissue, compared with the corresponding implant without a patch. X-ray images showed that the radius with the bone patch had higher opacity than that of the control, which was consistent with the results obtained via histological analysis. Evidently, the nHAp-embedded bone-patch scaffold has considerable potential for application in the field of orthopedics of bone regeneration.
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Quantum dots incorporated magnetic nanoparticles for imaging colon carcinoma cells.
J Nanobiotechnology
PUBLISHED: 06-07-2013
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Engineered multifunctional nanoparticles (NPs) have made a tremendous impact on the biomedical sciences, with advances in imaging, sensing and bioseparation. In particular, the combination of optical and magnetic responses through a single particle system allows us to serve as novel multimodal molecular imaging contrast agents in clinical settings. Despite of essential medical imaging modalities and of significant clinical application, only few nanocomposites have been developed with dual imaging contrast. A new method for preparing quantum dots (QDs) incorporated magnetic nanoparticles (MNPs) based on layer-by-layer (LbL) self-assembly techniques have developed and used for cancer cells imaging.
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Perception of Influencing Factors on Acceptance of Mobile Health Monitoring Service: A Comparison between Users and Non-users.
Healthc Inform Res
PUBLISHED: 05-10-2013
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To improve and promote mobile health monitoring services, this study investigated the perception of various factors influencing the acceptance of services between users and non-users.
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Subtle cytotoxicity and genotoxicity differences in superparamagnetic iron oxide nanoparticles coated with various functional groups.
Int J Nanomedicine
PUBLISHED: 12-07-2011
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Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely utilized for the diagnosis and therapy of specific diseases, as magnetic resonance imaging (MRI) contrast agents and drug-delivery carriers, due to their easy transportation to targeted areas by an external magnetic field. For such biomedical applications, SPIONs must have multifunctional characteristics, including optimized size and modified surface. However, the biofunctionality and biocompatibility of SPIONs with various surface functional groups of different sizes have yet to be elucidated clearly. Therefore, it is important to carefully monitor the cytotoxicity and genotoxicity of SPIONs that are surfaced-modified with various functional groups of different sizes. In this study, we evaluated SPIONs with diameters of approximately 10 nm and 100~150 nm, containing different surface functional groups. SPIONs were covered with -O? groups, so-called bare SPIONs. Following this, they were modified with three different functional groups--hydroxyl (-OH), carboxylic (-COOH), and amine (-NH?) groups--by coating their surfaces with tetraethyl orthosilicate (TEOS), (3-aminopropyl)trimethoxysilane (APTMS), TEOS-APTMS, or citrate, which imparted different surface charges and sizes to the particles. The effects of SPIONs coated with these functional groups on mitochondrial activity, intracellular accumulation of reactive oxygen species, membrane integrity, and DNA stability in L-929 fibroblasts were determined by water-soluble tetrazolium, 2,7-dichlorodihydrofluorescein, lactate dehydrogenase, and comet assays, respectively. Our toxicological observations suggest that the functional groups and sizes of SPIONs are critical determinants of cellular responses, degrees of cytotoxicity and genotoxicity, and potential mechanisms of toxicity. Nanoparticles with various surface modifications and of different sizes induced slight, but possibly meaningful, changes in cell cytotoxicity and genotoxicity, which would be significantly valuable in further studies of bioconjugation and cell interaction for drug delivery, cell culture, and cancer-targeting applications.
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Various preparation methods of highly porous hydroxyapatite/polymer nanoscale biocomposites for bone regeneration.
Acta Biomater
PUBLISHED: 04-27-2011
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Tissue engineering utilizes expertise in the fields of materials science, biology, chemistry, transplantation medicine, and engineering to design materials that can temporarily serve in a structural and/or functional capacity during regeneration of a defect. Hydroxyapatite (HAp) scaffolds are among the most extensively studied materials for this application. However, HAp has been reported to be too weak to treat such defects and, therefore, has been limited to non-load-bearing applications. To capitalize the advantages of HAp and at the same time overcome the drawbacks nanocrystalline HAp (nHAp) is combined with various types of bioactive polymers to generate highly porous biocomposite materials that are used for osteoconduction in the field of orthopedic surgery. In this study we have reviewed nanosized HAp-based highly porous composite materials used for bone tissue engineering, introduced various fabrication methods to prepare nHAp/polymer composite scaffolds, and characterized these scaffolds on the basis of their biodegradability and biocompatibility through in vitro and in vivo tests. Finally, we provide a summary and our own perspectives on this active area of research.
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Silver nanowire embedded in P3HT:PCBM for high-efficiency hybrid photovoltaic device applications.
ACS Nano
PUBLISHED: 03-31-2011
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A systematic approach has been followed in the development of a high-efficiency hybrid photovoltaic device that has a combination of poly(3-hexylthiophene) (P3HT), [6,6]-phenyl C61-butyric acid methyl ester (PCBM), and silver nanowires (Ag NWs) in the active layer using the bulk heterojunction concept. The active layer is modified by utilizing a binary solvent system for blending. In addition, the solvent evaporation process after spin-coating is changed and an Ag NWs is incorporated to improve the performance of the hybrid photovoltaic device. Hybrid photovoltaic devices were fabricated by using a 1:0.7 weight ratio of P3HT to PCBM in a 1:1 weight ratio of o-dichlorobenzene and chloroform solvent mixture, in the presence and absence of 20 wt % of Ag NWs. We also compared the photovoltaic performance of Ag NWs embedded in P3HT:PCBM to that of silver nanoparticles (Ag NPs). Atomic force microscopy, scanning electron microscopy, transmittance electron microscopy, UV-visible absorption, incident photon-to-current conversion efficiency, and time-of-flight measurements are performed in order to characterize the hybrid photovoltaic devices. The optimal hybrid photovoltaic device composed of Ag NWs generated in this effort exhibits a power conversion efficiency of 3.91%, measured by using an AM 1.5G solar simulator at 100 mW/cm(2) light illumination intensity.
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Nanoscale hydroxyapatite particles for bone tissue engineering.
Acta Biomater
PUBLISHED: 03-11-2011
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Hydroxyapatite (HAp) exhibits excellent biocompatibility with soft tissues such as skin, muscle and gums, making it an ideal candidate for orthopedic and dental implants or components of implants. Synthetic HAp has been widely used in repair of hard tissues, and common uses include bone repair, bone augmentation, as well as coating of implants or acting as fillers in bone or teeth. However, the low mechanical strength of normal HAp ceramics generally restricts its use to low load-bearing applications. Recent advancements in nanoscience and nanotechnology have reignited investigation of nanoscale HAp formation in order to clearly define the small-scale properties of HAp. It has been suggested that nano-HAp may be an ideal biomaterial due to its good biocompatibility and bone integration ability. HAp biomedical material development has benefited significantly from advancements in nanotechnology. This feature article looks afresh at nano-HAp particles, highlighting the importance of size, crystal morphology control, and composites with other inorganic particles for biomedical material development.
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Molecular recognition of arginine by supramolecular complexation with calixarene crown ether based on surface plasmon resonance.
Int J Mol Sci
PUBLISHED: 02-10-2011
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Arginine plays an important role in cell division and the functioning of the immune system. We describe a novel method by which arginine can be identified using an artificial monolayer based on surface plasmon resonance (SPR). The affinity of arginine binding its recognition molecular was compared to that of lysine. In fabrication of an arginine sensing interface, a calix[4]crown ether monolayer was anchored onto a gold surface and then characterized by Fourier Transform infrared reflection absorption spectroscopy, atomic force microscopy, and cyclic voltammetry. The interaction between arginine and its host compound was investigated by SPR. The calix[4]crown ether was found to assemble as a monolayer on the gold surface. Recognition of calix[4]crown monolayer was assessed by the selective binding of arginine. Modification of the SPR chip with the calix[4]crown monolayer provides a reliable and simple experimental platform for investigation of arginine under aqueous conditions.
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Synthesis and characterization of gold-deposited red, green and blue fluorescent silica nanoparticles for biosensor application.
Chem. Commun. (Camb.)
PUBLISHED: 08-12-2010
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Fluorescent silica nanoparticles deposited with highly monodisperse gold nanoparticles (1-2 nm) were synthesized via the W/O method and intensive ultrasound irradiation. A large surface area of gold-doped fluorescent silica nanoparticle serves as a platform to immobilize a specific binding protein for biomolecules interaction in bioimaging applications.
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"Cloud" assemblies: quantum dots form electrostatically bound dynamic nebulae around large gold nanoparticles.
Phys Chem Chem Phys
PUBLISHED: 07-29-2010
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Dynamic self-assembled structures of nanoparticles can be produced using predominantly electrostatic interactions. Such assemblies were made from large, positively charged Au metal nanoparticles surrounded by an electrostatically bound cloud of smaller, negatively charged CdSe/ZnS or CdTe quantum dots. At low concentrations they are topologically similar to double electric layers of ions and corona-like assemblies linked by polymer chains. They can also be compared to the topological arrangement of some planetary systems in space. The great advantages of the cloud assemblies are (1) their highly dynamic nature compared to more rigid covalently bound assemblies, (2) simplicity of preparation, and (3) exceptional versatility in components and resulting optical properties. Photoluminescence intensity enhancement originating from quantum resonance between excitons and plasmons was observed for CdSe/ZnS quantum dots, although CdTe dots displayed emission quenching. To evaluate more attentively their dynamic behavior, emission data were collected for the cloud-assemblies with different ratios of the components and ionic strengths of the media. The emission of the system passes through a maximum for 80 QDs???1 Au NP as determined by the structure of the assemblies and light absorption conditions. Ionic strength dependence of luminescence intensity contradicts the predictions based on the Gouy-Chapman theory and osmotic pressure at high ionic strengths due to formation of larger chaotic colloidally stable assemblies. "Cloud" assemblies made from different nanoscale components can be used both for elucidation of most fundamental aspects of nanoparticle interactions, as well as for practical purposes in sensing and biology.
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Functionalization effects of single-walled carbon nanotubes as templates for the synthesis of silica nanorods and study of growing mechanism of silica.
ACS Nano
PUBLISHED: 06-12-2010
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Silica nanorods were successfully prepared through a sol-gel process in the presence of carboxylic-functionalized single-walled carbon nanotubes (C-SWCNTs). The effect of chemical functionalization of single-walled carbon nanotubes (SWCNTs) on the growth of the silica layer was investigated using pristine SWCNTs (P-SWCNTs) and C-SWCNTS. The C-SWCNTs served as a unique template to fabricate silica hybrid composite materials. The crystalline formation and growing mechanism of the silica layer on C-SWCNTs were explained by the hydrolysis and chemical bonding between silica precursors and carboxylated SWCNTs. The C-SWCNTs, as templates, were successfully encapsulated using silica, and used templates were removed by oxidation at high temperature. Finally, silica nanorods/nanowires were synthesized in forms of mold, and this silica fabrication mechanism could be applied for large-scale production of silica nanomaterials and highly flexible nanocomposites. The sequence of a silica encapsulation process of C-SWCNTs and removed C-SWCNTs was characterized using SEM, TEM, EDX, FT-IR and Raman spectroscopy, XRD, and electrical analysis.
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Light-controlled self-assembly of semiconductor nanoparticles into twisted ribbons.
Science
PUBLISHED: 02-11-2010
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The collective properties of nanoparticles manifest in their ability to self-organize into complex microscale structures. Slow oxidation of tellurium ions in cadmium telluride (CdTe) nanoparticles results in the assembly of 1- to 4-micrometer-long flat ribbons made of several layers of individual cadmium sulfide (CdS)/CdTe nanocrystals. Twisting of the ribbons with an equal distribution of left and right helices was induced by illumination with visible light. The pitch lengths (250 to 1500 nanometers) varied with illumination dose, and the twisting was associated with the relief of mechanical shear stress in assembled ribbons caused by photooxidation of CdS. Unusual shapes of multiparticle assemblies, such as ellipsoidal clouds, dog-bone agglomerates, and ribbon bunches, were observed as intermediate stages. Computer simulations revealed that the balance between attraction and electrostatic repulsion determines the resulting geometry and dimensionality of the nanoparticle assemblies.
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Phenylalanine sensing based on surface plasmon resonance.
J Nanosci Nanotechnol
PUBLISHED: 11-14-2009
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A phenylalanine sensing system was constructed with photochromic spiroxazine derivative via surface plasmon resonance (SPR). Recognition-functional spiroxazine monolayer was formed on Au surface by self-assembly. After spectroscopic characterizations of monolayer, various concentrations of d- and l-phenylalanine were employed as analytes on UV addressable ring-opened spiroxazine monolayer. The different SPR angle shift derived from interaction between d- and l-phenylalanine and spiroxazine monolayer can be explained by the different dipole moment of ionic complexes. Computer simulations using Molecular Orbital PACkage AM1 approximation reinforced the reliability of the experimental results. To confirm the long-time stability of spiroxazine monolayer, we measured SPR response of spiroxazine monolayer with repetitive UV-on and off. These experimental results suggest that it can be applicable to simple analysis of interaction between zwitterionic recognition-functional molecule and analyte.
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Surface plasmon resonance investigation of a copolymer containing spiroxazine.
J Nanosci Nanotechnol
PUBLISHED: 11-14-2009
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Spiroxazines are a class of photochromic compounds whose molecular structures are alterable upon exposure to UV/visible light. The typical reaction of spiroxazines is the conversion between the non-polar ring-closure form and polar ring-open form. In this work, copolymer of 1,6-heptadiyne derivatives containing a spiroxazine was used as photochromic material. Precise photochromic properties of the copolymers thin-film were evaluated through measuring dielectric constant, optical constant and thickness by surface plasmon resonance (SPR) with multi-solvent approach. The change in structure under UV-light irradiation is accompanied by increase of dielectric constant. However, dielectric constant and UV-induced thickness change of the photochromic polymer thin-film are independent of film thickness.
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Photoluminescence up-conversion of bioconjugated hybrids on CdTe and Au nanoparticles.
J Nanosci Nanotechnol
PUBLISHED: 11-14-2009
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Semiconductor nanomaterials have attracted considerable attention in the design of high efficiency PL up-conversion in heterojunctions or nanostructures at extremely low continuous wave (cw)-excitation intensity. In this study, bioconjugated hybrids were constructed using CdTe and Au nanoparticles (NPs), where two-fold PL enhancement was observed in the solution state. These results are in accordance with theoretical predictions of the local-field effects associated with the combined influence of strong localization of the collective plasmon modes in metallic-semiconducting hybrids and multi-photon absorption into its localized plasmon modes. The feasibility of the nanohybrids as sensors was demonstrated by breaking the bioconjugation through thermal stress, which induced a rapid decrease in luminescence intensity. It is believed that the phenomena is applicable to high-compacted optoelectronic devices and sensing systems that take advantage of both quantum confinement effects and nonlinear optical properties.
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Hydroxyapatite coating on damaged tooth surfaces by immersion.
Biomed Mater
PUBLISHED: 04-06-2009
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Hydroxyapatite (HAp) was coated on scratched areas of a human tooth and HAp disks by the immersion method in a HAp colloidal solution (< or =20 microm of average diameter dispersed in DI water). The surface morphologies of the scratched area after immersion for 1-3 months were investigated showing that the damaged surfaces were remarkably recovered. Then, the mechanical property and chemical stability of the HAp coating layers on both specimens were determined via the Vickers hardness test and concentration measurement of extracted Ca2+ ions, respectively, after strong acidic treatment. The cellular behavior of mouse calvaria-derived pre-osteoblastic cells (MC3T3-E1) was also examined on the HAp layers regenerated on micro-scratched HAp disks for the purpose of their potential applications on maxillofacial bone conservation and reconstruction for prosthetic dentistry, and artificial disk preparation of a vertebral column. The notable loss of Ca2+ ions under a highly acidic condition was not observed in the layers coated by HAp adsorption, indicating that the coating surface was well adhered with the original surfaces of the respective specimen. Moreover, the HAp adsorption did not adversely affect the adhesion, growth and proliferation of MC3T3-E1 cells on the coated HAp layers for up to 21 days. These results suggest that the HAp coating on the scratched areas of the tooth would be effectively applicable for the development of long-term prevention of micro-cleavage and tooth health supporters to reduce discoloration and further maxillofacial and orthopedic applications.
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Synthesis of length-controlled aerosol carbon nanotubes and their dispersion stability in aqueous solution.
Langmuir
PUBLISHED: 01-10-2009
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A one-step method combining spray pyrolysis and thermal chemical vapor deposition (CVD) processes was developed to grow hybrid carbon nanotube (CNT)-bimetallic composite particles. Nickel, aluminum, and acetylene were used as the catalytic site, noncatalytic matrix, and hydrocarbon source, respectively. The bimetallic particles (i.e., Al-Ni) were spray pyrolized and subsequently passed through thermal CVD. During the thermal CVD, the catalytic decomposition of acetylene occurred on the free-floating bimetallic particles so that sea urchin-like CNTs were radially grown. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses revealed the CNTs to have a uniform diameter of approximately 10 +/- 2 nm. The length of the CNTs was controlled by varying the residence time of the bimetallic nanoparticles with a length of 200-1000 nm. After nitric acid treatment, the CNTs were released by melting the bimetallic particles. The resulting CNTs were then dispersed in an aqueous solution to examine the effect of the length of CNTs on their dispersion stability, which is a critical issue for the stability and repeatability of the heat transfer performance in nanofluids. Ultraviolet-visible (UV-vis) spectrometer analysis showed that shorter CNTs were less stable than the longer CNTs due to the higher mobility-induced agglomeration of the shorter CNTs.
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In-vivo and in-vitro biocompatibility evaluations of silver nanoparticles with antimicrobial activity.
J Nanosci Nanotechnol
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In this study, the biocompatibility and antimicrobial activity of silver nanoparticles (Ag NPs) were evaluated in vitro and in vivo. The cytotoxicity of Ag NPs (average diameter: 2-5 nm) against CHO-K1 cells was determined via WST-8 assay, and their genotoxicity was examined via Salmonella typhimurium reverse mutation assay (Ames test). The acute toxicity and intracutaneous reactivity of Ag NPs were evaluated using animal models of mice and rabbits, respectively. The antibacterial effects of Ag NPs on the Gram (-) bacterial strains of Escherichia coli ATCC 8739 and Pseudomonas aeruginosa ATCC 9027 and on the Gram (+) bacterial strains of Staphylococcus aureus ATCC 6538p and Bacillus subtilius ATCC 6633 were determined by measuring the minimum inhibitory concentrations. The Ag NPs were highly cytotoxic to the L-929 cells at over 2 ppm but were non-cytotoxic at lower than 1 ppm. Moreover, the Ag NPs at 1 ppm or lower did not show genotoxicity, acute toxicity and intracutaneous reactivity. It was also found that the Ag NPs exerted effective antimicrobial activities on both the Gram (-) and (+) bacterial strains within the range from 0.06 to 0.98 ppm for 50% MIC.
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Photoluminescence enhancement of quantum dots on Ag nanoneedles.
Nanoscale Res Lett
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Noble metal nanostructure allows us to tune optical and electrical properties, which has high utility for real-world application. We studied surface plasmon-induced emission of semiconductor quantum dots (QDs) on engineered metallic nanostructures. Highly passive organic ZnS-capped CdSe QDs were spin-coated on poly-(methyl methacrylate)-covered Ag films, which brought QDs near the metallic surface. We obtained the enhanced electromagnetic field and reduced fluorescence lifetimes from CdSe/ZnS QDs due to the strong coupling of emitter wave function with the Ag plasmon resonance. Observed changes include a six-fold increase in the fluorescence intensity and striking reduction in fluorescence lifetimes of CdSe/ZnS QDs on rough Ag nanoneedle compared to the case of smooth surfaces. The advantages of using those nanocomposites are expected for high-efficiency light-emitting diodes, platform fabrication of biological and environmental monitoring, and high-contrast imaging.
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Microfabrication and optical properties of highly ordered silver nanostructures.
Nanoscale Res Lett
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Using thermal evaporation, we fabricated five uniform and regular arrays of Ag nanostructures with different shapes that were based on an anodized aluminum oxide template and analyzed their optical properties. Round-top-shaped structures are obtained readily, whereas to obtain needle-on-round-top-shaped and needle-shaped structures, control of the directionality of evaporation, pore size, length, temperature of the substrate, etc., was required. We then observed optical sensitivity of the nanostructures by using surface-enhanced Raman scattering, and we preliminarily investigated the dependency of Raman signal to the roughness and shape of the nanostructures.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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