共查询到20条相似文献,搜索用时 15 毫秒
1.
Dongguang Yin Binhu Liu Le Zhang Minghong Wu 《Journal of nanoparticle research》2011,13(12):7271-7276
In this study, a new approach for the preparation of a fluorescent europium(III) complex-doped silica nanoparticles has been
developed. The synthesis process involved the following steps: (1) preparing silica nanoparticles by water-in-oil microemulsion
method, (2) dyeing the spherical silica particles by europium(III): naphtoyltrifluoroacetone (NTA):trioctylphosphineoxide
(TOPO), (3) adsorbing polyvinylpyrrolidone (PVP) onto the core structure and growing silica on PVP surface. The as-prepared
nanoparticles exhibited stronger emission intensity, higher photo- and chemical stability. Despite the fact that europium(III)
complex was doped into the nanoparticles, its fluorescence properties such as a wide Stokes shift, a narrow emission peak,
and long fluorescence lifetime, were retained. The nanoparticles are uniform in shape and size (50 ± 5 nm in diameter). This
study could provide new avenue for the fabrication of Eu: NTA:TOPO-based nanoparticles, facilitating their application in
bioassay issues. 相似文献
2.
Darko Makovec Alojz Kodre Iztok Ar?on Miha Drofenik 《Journal of nanoparticle research》2009,11(5):1145-1158
The structure of Mn0.5Zn0.5Fe2O4 spinel ferrite nanoparticles is studied as a function of their size and the experimental conditions of their synthesis using
X-ray absorption spectroscopy. The nanoparticles of different sizes down to approximately 2 nm and with a narrow size distribution
were synthesized using co-precipitation in reverse microemulsions. Simultaneous refinement of the X-ray absorption fine structure
(EXAFS) of three constituting metals shows a migration of Mn and Zn ions to the octahedral site of the spinel lattice compensated
by the corresponding migration of the Fe ions. To a smaller extent, Mn ions switch the occupation site already in bulk and
in larger nanoparticles, while a sporadic migration of Zn is detected only in the nanoparticles with sizes below approximately
5 nm. X-ray absorption near edge structure (XANES) reveals considerable variations in the position of the Mn K edge, suggesting the average Mn valence in the nanoparticles to be higher than 3+. Annealing at 500 °C relaxes the structure
of as-synthesized nanoparticles toward the structure of the ceramic bulk standard.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
N. Nishida A. Miyashita N. Hashimoto H. Murayama H. Tanaka 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,63(2):307-310
Copper nanoparticles have attracted much attention because of their low cost, and because
their use can contribute toward the sustainability of metal resources. In this study,
copper nanoparticles were synthesized by the photoirradiation of copper acetate solution
at room temperature. The diameter and chemical composition of the obtained copper
nanoparticles were analyzed using field-emission scanning electron microscope (FE-SEM)
spectrophotometer and an X-ray photoelectron spectrometer. Well-dispersed copper
nanoparticles with ~5 nm in diameter were observed in the solution. On the other hand,
when the nanoparticle solution was exposed to fresh air, nanoparticles were not observed
in the solution. Furthermore, the copper nanoparticles were recovered from a solution of
decomposed nanoparticles by re-photoirradiation. 相似文献
4.
Immobilized nanosized metal (oxides) on carbonaceous carriers were prepared by hydrolysis under mild conditions by using the
carrier pores as a kind of nanoreactor. Metal alkoxide vapor was adsorbed on the carrier and then formed the product upon
exposure to water vapor. With this facile method, Titania, Vanadia, Rhodium (oxide), and Platinum (oxide) nanostructures were
prepared at high yields, high loadings, and good dispersion in the carrier material. High number concentrations of spheroidal
nanoparticles of uniform size (diameter ca. 5 nm) were obtained from less reactive precursors, whereas with highly reactive
precursors, such nanoparticles occurred only after subsequent calcination. Nanoparticles appeared to be the thermodynamically
stable form of the metal (oxide) produced in the pores. Highly reactive precursors formed metastable seeds, which nucleated
and restructured into nanoparticles upon subsequent exposure to heat. The presented method allows for preparation of metal
(oxide) nanostructures and effective control of their size and shape. 相似文献
5.
Sébastien Abramson Liliane Srithammavanh Jean-Michel Siaugue Olivier Horner Xiangzhen Xu Valérie Cabuil 《Journal of nanoparticle research》2009,11(2):459-465
The preparation of core-shell-shell γ-Fe2O3/SiO2/TiO2 nanoparticles of few tens nanometers is performed by successively coating onto magnetic nanoparticles a SiO2 layer and a TiO2 layer, using sol–gel methods. The thickness of the two layers and the aggregation state of the particles can be controlled
by the experimental conditions used for the two coatings. These composite nanoparticles may find application as magnetic photocatalysts,
since they are characterized by their small diameters which allow a good accessibility to the TiO2 shell.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
6.
In this work, silver nanoparticles are synthesized using a simple and sensitive method by using double-stranded DNA (dsDNA-Ag NPs) as a template. The prepared dsDNA-Ag NPs are characterized by fluorescence spectroscopy analysis, X-ray photoelectron spectroscopy analysis, and transmission electron microscopy analysis. The excitation wavelength of the prepared silver nanoparticles is 295 nm, the emission wavelength is 377 nm, the average particle size is 11.2 nm, and the dispersion is uniform with pleasurable stability. The nanomaterials are used as fluorescent probes to detect glutathione (GSH). After adding glutathione to the dsDNA-Ag NPs fluorescent probes, the fluorescence of dsDNA-Ag NPs is burst due to electron transfer and S Ag bond generation, and the linear range of detection concentration is 0–90 mm with a detection limit of 0.37 mm . 相似文献
7.
Lucas Oorlynck Yera Ye. Ussembayev Ingrid Amer Cid Juan Fraire Charlotte Hinnekens Kevin Braeckmans Filip Strubbe 《Particle & Particle Systems Characterization》2023,40(1):2200152
To enable detailed studies of interactions between nanoparticles and their environment and the correlations between various nanoparticle properties, one must go beyond ensemble averages and toward single-particle measurements. However, current methodologies for the single-nanoparticle analysis of charge and size either lack the flexibility to study dynamic processes on the single-particle level or are highly specific and require complex microfluidic devices. In addition, accurate measurements of the electrophoretic mobility (or zeta-potential) based on the optical detection of single nanoparticles remain challenging due to the low photon budget, the required sampling frequency, and the fact that electroosmosis in typical microfluidic devices must be analyzed carefully. In this study, a method is investigated to accurately characterize the electrophoretic mobility of individual nanoparticles and estimate their size by simultaneously analyzing the electrokinetic- and Brownian motion in a simple microfluidic channel. Fast laser scanning excitation and sensitive detection of fluorescent photons enable single-nanoparticle velocimetry experiments in an oscillating electric field at high frame rates. 相似文献
8.
Finding some economical and environmentally friendly inhibitors was always one of our research goals. The present paper researched
the method of rapid controlled precipitation (RCP) and the results showed it was reliable and suitable as the method of evaluating
the scaling. Then through the method of RCP, the paper would investigate four kinds of metal ions as the inhibitors, the results
showed the zinc ion and copper ion were suitable as the inhibitors. In the 300-mL solution (calcium ion concentration of 126.5 mg
L−1), the total efficiency of 100% was reached for the copper ion concentration of 0.8 mg L−1 and for the zinc ion concentration of 0.3 mg L−1. After choosing the zinc ion and copper ion as the inhibitors, this paper also investigated the cooperative effect of the
mixed metal ions, the results showed the mixed ions would not change the inhibition effectiveness of any single metal ion,
but could affect the calcium carbonate germination and change the crystal morphology.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
H. Y. Tsai C. Y. Chang Y. C. Li W. C. Chu K. Viswanathan C. Bor Fuh 《Journal of nanoparticle research》2011,13(6):2461-2467
We combined a sandwich immunoassay, anti-CEA/CEA/anti-CEA, with functional magnetic (~80 nm) and fluorescent (~180 nm) nanoparticles
in magnetic separators to demonstrate a detection method for carcinoembryonic antigen (CEA). Determination of CEA in serum
can be used in clinical diagnosis and monitoring of tumor-related diseases. The CEA concentrations in samples were deduced
and determined based on the reference plot using the measured fluorescent intensity of sandwich nanoparticles from the sample.
The linear range of CEA detection was from 18 ng/mL to 1.8 pg/mL. The detection limit of CEA was 1.8 pg/mL. In comparison
with most other detection methods, this method had advantages of lower detection limit and wider linear range. The recovery
was higher than 94%. The CEA concentrations of two serum samples were determined to be 9.0 and 55 ng/mL, which differed by
6.7% (9.6 ng/mL) and 9.1% (50 ng/mL) from the measurements of enzyme-linked immunosorbent assay (ELISA), respectively. The
analysis time can be reduced to one third of ELISA. This method has good potential for other biomarker detections and biochemical
applications. 相似文献
10.
A new fluorescent probe 3, has been developed for the detection of Fe(III) in water based samples. The design of 3 involved the incorporation of Fe(III) binding sites observed in naturally occurring Siderophores into a synthetic sensing
assembly. The probe, containing two Schiff base receptors connected to a mesitylene platform, was prepared in two steps. The
dipodal sensor displayed good selectivity for Fe(III) when tested against other physiological and environmentally important
metal ions, in HEPES buffered solution at pH 7.0, through a quenching of the fluorescent intensity. Stern-Volmer analysis
of this quenching interaction indicated a 1:1 (host : guest) binding stoichiometry between the probe and Fe(III). The association
constant, K
a
calculated using the Benesi-Hildebrand equation was found to be 3.8 × 104 M−1. Crucially, the sensor was capable of measuring Fe(III) competitively in solutions containing both Fe(III) and Cu(II). Thus,
the adoption of Fe(III) binding sites found in nature, into synthetic luminescent assemblies has proven an effective design
strategy for the development of new Fe(III) probes.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
11.
Anthony W. Musumeci Zhi Ping Xu Suzanne V. Smith Rodney F. Minchin Darren J. Martin 《Journal of nanoparticle research》2010,12(1):111-120
Stable and non-invasive fluorescent probes for nanotoxicological investigations are greatly needed to track the fate of nanoparticles
in biological systems. The potential for terbium (Tb) to act as a fluorescent probe and its effect on layered double hydroxide
(LDH) nanoparticle morphology are presented in this study. Incorporation of Tb during synthesis offers a simple methodology
to easily tailor LDH nanoparticle thickness. A three-fold reduction in the average crystallite thickness (from 13 to 4 nm)
has been achieved, whilst preferential lateral growth of LDH nanoparticles in the a-b crystal plane has been observed with increasing Tb loadings. Remarkably, Tb–LDH nanoparticles have emitted green fluorescence
with a fluorescence quantum yield of 0.044. 相似文献
12.
The ubiquity of naturally occurring nanoparticles in the aquatic environment is now widely accepted, but a better understanding
of the conditions that promote their formation and persistence is needed. Using cadmium sulfide (CdS) as a model metal sulfide
species, thiolate-capped CdS nanoparticles were prepared in the laboratory to evaluate how aquatic conditions influence metal
sulfide nanoparticle growth and stability. This work examines CdS nanoparticle growth directly in aqueous solution at room
temperature by utilizing the size-dependent spectroscopic properties of semiconductors detectable by UV/vis. CdS nanoparticle
growth was governed by oriented attachment, a non-classical mechanism of crystallization in which small precursor nanoparticles
coalesce to form larger nanoparticle products. Nanoparticle growth was slowed with increasing capping agent and decreasing
ionic strength. In addition to examining the short-term (hours) growth of the nanoparticles, a long-term study was conducted
in which cysteine-capped CdS nanoparticles were monitored over 3 weeks in solutions of various ionic strengths. The long-term
study revealed an apparent shift from small nanoparticles to nanoparticles twice their original size, suggesting nanoparticle
growth may continue through oriented attachment over longer time scales. High-ionic strength solutions resulted in salt-induced
aggregation and eventual settling of nanoparticles within days, whereas low-ionic strength solutions were stable against settling
over the course of the experiment. Sulfide recovery from cysteine-capped CdS nanoparticles as acid volatile sulfide was nearly
quantitative after 2 weeks in fully oxygenated water, demonstrating significantly slowed oxidation of sulfide when complexed
to Cd(II) within CdS nanoparticles. The nanoparticles were also shown to be resistant to oxidation by Fe(III) (hydr)oxide.
This study illustrates that aggregation, rather than chemical oxidation, is likely more important to the lifetime of many
metal sulfide nanoparticles in the aquatic environment. 相似文献
13.
Thomas Schüler Andrea Steinbrück Grit Festag Robert M?ller Wolfgang Fritzsche 《Journal of nanoparticle research》2009,11(4):939-946
Based on their interesting properties, metal nanoparticles show the potential as an analytical tool in electronic (Burmeister
et al. 2004), optical (Yguerabide and Yguerabide 1998), and catalytic applications (Liu 2006). Their characteristics depend on the composition, shape, and size of the single particles. These various properties are
utilized in many different approaches such as optics, magnetics (Lang et al. 2007), and laser technology (Csaki et al. 2007). We investigated an alternative method for the synthesis of nanoparticles. In this case, an enzyme, horseradish peroxidase,
induces a silver deposition and replaces a metal nanoparticle as the reaction seed. Depending on the reaction time, we could
obtain particles in a range of few nanometers up to more than 250 nm. For a better understanding of the enzymatic silver deposition
process, the silver particles produced by this process were analyzed by SEM, TEM, and atomic force microscopy (AFM) on a single
particle level after different enhancement times. The AFM images were utilized for the characterization of particle height
and volume to study the enzyme kinetics, i.e., the particle growth process. Thereby, two different phases are described: a
first growth phase probably induced by the enzyme-related growth, and a second, more unspecific growth based on the metal
deposition onto the silver deposits. These findings may help to use the enzyme-induced silver deposition in a quantitative
manner for bioanalytical applications. 相似文献
14.
J. H. Thorat K. G. Kanade L. K. Nikam P. D. Chaudhari R. P. Panmand B. B. Kale 《Journal of nanoparticle research》2012,14(2):657-10
In this study, we report the synthesis of well-aligned nanocrystalline hexagonal zinc oxide (ZnO) nanoparticles by facile
solid-state and co-precipitation method. The co-precipitation reactions were performed using aqueous and ethylene glycol (EG)
medium using zinc acetate and adipic acid to obtain zinc adipate and further decomposition at 450 °C to confer nanocrystalline
ZnO hexagons. XRD shows the hexagonal wurtzite structure of the ZnO. Thermal study reveals complete formation of ZnO at 430 °C
in case of solid-state method, whereas in case of co-precipitation method complete formation was observed at 400 °C. Field
emission scanning electron microscope shows spherical morphology for ZnO synthesized by solid-state method. The aqueous-mediated
ZnO by co-precipitation method shows rod-like morphology. These rods are formed via self assembling of spherical nanoparticles,
however, uniformly dispersed spherical crystallites were seen in EG-mediated ZnO. Transmission electron microscope (TEM) investigations
clearly show well aligned and highly crystalline transparent and thin hexagonal ZnO. The particle size was measured using
TEM and was observed to be 50–60 nm in case of solid-state method and aqueous-mediated co-precipitation method, while 25–50 nm
in case of EG-mediated co-precipitation method. UV absorption spectra showed sharp absorption peaks with a blue shift for
EG-mediated ZnO, which demonstrate the mono-dispersed lower particle size. The band gap of the ZnO was observed to be 3.4 eV
which is higher than the bulk, implies nanocrystalline nature of the ZnO. The photoluminescence studies clearly indicate the
strong violet and weak blue emission in ZnO nanoparticles which is quite unique. The process investigated may be useful to
synthesize other oxide semiconductors and transition metal oxides. 相似文献
15.
Sumanta Kumar Sahu Arindam Chakrabarty Dipsikha Bhattacharya Sudip K. Ghosh Panchanan Pramanik 《Journal of nanoparticle research》2011,13(6):2475-2484
The aim of this study was to develop a simple, cheap, and rapid method for purification of His-tag recombinant proteins with
high yields. The new immobilized metal ion affinity adsorbent containing superparamagnetic nanoparticles and hydrophilic resins
are proposed here to improve the purification of His-tagged recombinant proteins. In this report, we have described the preparation
of nanosized superparamagnetic nanoparticles (Fe3O4) which were prepared by chemical precipitation method followed by surface modification using phosphonomethyl iminodiacetic
acid. The stable surface functionalized nanoparticles were further linked with Ni2+ for purification of 6× His-tagged proteins. The phosphonate group of the N-phosphonomethyl iminodiacetic acid ligand acts as a surface anchoring agent on magnetite nanoparticles and the remaining
free –COOH groups outside for binding with Ni2+ ions. The nanoparticles were approximately 6–8 nm in size and were stable and had negligible non-specific binding for protein.
The proteins were purified within 1 h and observed on sodium dodecyl sulfate-polyacrylamide electrophoresis gel. 相似文献
16.
Jing Tang Fung Suong Ou Huei Pei Kuo Min Hu William F. Stickle Zhiyong Li R. Stanley Williams 《Applied Physics A: Materials Science & Processing》2009,96(4):793-797
We created novel surface-enhanced Raman spectroscopy (SERS) substrates by metalization (Ag) of Si nanograss prepared by a
Bosch process which involves deep reactive ion etching of single crystalline silicon. No template or lithography was needed
for making the Si nanograss, thus providing a simple and inexpensive method to achieve highly sensitive large-area SERS substrates.
The dependence of the SERS effect on the thickness of the metal deposition and on the surface morphology and topology of the
substrate prior to metal deposition was studied in order to optimize the SERS signals. We observed that the Ag-coated Si nanograss
can achieve uniform SERS enhancement over large area (∼1 cm ×1 cm) with an average EF (enhancement factor) of 4.2×108 for 4-mercaptophenol probe molecules.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
17.
F. Xie K. Drozdowicz-Tomsia T. Shtoyko E. M. Goldys 《Journal of nanoparticle research》2011,13(2):613-624
Detection and identification of low abundance biomarker proteins is frequently based on various types of membrane-based devices.
Lowering of the protein detection limits is vital in commercial applications such as lateral flow assays and in Western blots
widely used in proteomics. These currently suffer from insufficient detection sensitivity and low retention for small 2–5 kDa
proteins. In this study, we report the deposition of two types of metal nanoparticles: gold colloids (50–95 nm diameter) and
silver fractals onto a range of commonly used types of membranes including polyvinylidene fluoride (PVDF). Due to strong affinity
of proteins to noble metals, such modified membranes have the potential to effectively capture trace proteins preventing their
loss. The membranes modified by metal particles were characterized optically and by SEM. The membrane performance in protein
dot blots was evaluated using the protein—fluorophore conjugates Deep Purple-bovine serum albumin and fluorescein—human serum
albumin. We found that the metal nanoparticles increase light extinction by metals, which is balanced by increased fluorescence,
so that the effective fluorescence signal is unchanged. This feature combined with the capture of proteins by the nanoparticles
embedded in the membrane increases the detection limit of membrane assays. 相似文献
18.
Abstract Heating tumors by nanoparticles and resistance in hypoxic tumor cells to a high temperature is emerging as an effective tool
in therapeutic oncology as nanomedicine tool. The art of imaging temperature in a tumor at various locations is emerging as
the selective approach of hyperthermia to monitor temperature and treat the tumor. However, thermometry and tumor cell interaction
with nanoparticles may monitor and evaluate the tumor cell survival after exposure to high physiological temperatures. The
application of 10–100 nanometer sized nanoparticles in tumor hyperthermia has emerged as an effective monitoring tool as magnetic
resonance (MR) thermal mapping. The temperature and nanoparticle magnetic moment relationship is specific. Furthermore, there
are two main issues that are unsolved as of yet. First issue is the relationship of tumor energy changes due to tumor magnetization;
linear attenuation after magnetic field and X-ray exposure with tissue temperature increase. The second issue is the undefined
behavior of the nanoparticle inside the tumor as diamagnetic or paramagnetic can be therapeutic and it depends on the tumor
tissue temperature. In vivo imaging such as MR thermometry mapping of different hypoxic tumor locations solves these issues
to some extent. The art of the nanoparticle-induced hyperthermia does have a great impact on public health as alternative
therapeutic oncology.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
I. Mohammed Sadiq Sunandan Pakrashi N. Chandrasekaran Amitava Mukherjee 《Journal of nanoparticle research》2011,13(8):3287-3299
In view of increasing commercial applications of metal oxide nanoparticles their toxicity assessment becomes important. Alumina
(Al2O3) nanoparticles have wide range of applications in industrial as well as personal care products. In the absence of prior report
on toxicological impact of alumina nanoparticles to microalgae, the principal objective of this study was to demonstrate the
effect of the nanoparticles on microalgae isolated from aquatic environment (Scenedesmus sp. and Chlorella sp.). The growth inhibitory effect of alumina nanoparticles was observed for both the species (72 h EC50 value, 45.4 mg/L for Chlorella sp.; 39.35 mg/L for Scenedesmus sp.). Bulk alumina also showed toxicity though to a lesser extent (72 h EC50 value, 110.2 mg/L for Chlorella sp.; 100.4 mg/L for Scenedesmus sp.). A clear decrease in chlorophyll content was observed in the treated cells compared to the untreated ones, more effect
being notable in the case of nanoparticles. Preliminary results based on FT-IR studies, optical and scanning electron microscopic
images suggest interaction of the nanoparticles with the cell surface. 相似文献
20.
Ying Cao Hua-Jie Wang Cui Cao Yuan-Yuan Sun Lin Yang Bao-Qing Wang Jian-Guo Zhou 《Journal of nanoparticle research》2011,13(7):2759-2767
In this article, a facile and environmentally friendly method was applied to fabricate BSA-conjugated amorphous zinc sulfide
(ZnS) nanoparticles using bovine serum albumin (BSA) as the matrix. Transmission electron microscopy analysis indicated that
the stable and well-dispersed nanoparticles with the diameter of 15.9 ± 2.1 nm were successfully prepared. The energy dispersive
X-ray, X-ray powder diffraction, Fourier transform infrared spectrograph, high resolution transmission electron microscope,
and selected area electron diffraction measurements showed that the obtained nanoparticles had the amorphous structure and
the coordination occurred between zinc sulfide surfaces and BSA in the nanoparticles. In addition, the inhibition effects
of BSA-conjugated amorphous zinc sulfide nanoparticles on tumor cells growth were described in detail by cell viability analysis,
optical and electron microscopy methods. The results showed that BSA-conjugated amorphous zinc sulfide nanoparticles could
inhibit the metabolism and proliferation of human hepatocellular carcinoma cells, and the inhibition was dose dependent. The
half maximal inhibitory concentration (IC50) was 0.36 mg/mL. Overall, this study suggested that BSA-conjugated amorphous zinc
sulfide nanoparticles had the application potential as cytostatic agents and BSA in the nanoparticles could provide the modifiable
site for the nanoparticles to improve their bioactivity or to endow them with the target function. 相似文献