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1.
Garima Singhal Riju Bhavesh Kunal Kasariya Ashish Ranjan Sharma Rajendra Pal Singh 《Journal of nanoparticle research》2011,13(7):2981-2988
Development of green nanotechnology is generating interest of researchers toward ecofriendly biosynthesis of nanoparticles.
In this study, biosynthesis of stable silver nanoparticles was done using Tulsi (Ocimum sanctum) leaf extract. These biosynthesized nanoparticles were characterized with the help of UV–vis spectrophotometer, Atomic Absorption
Spectroscopy (AAS), Dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR),
and Transmission electron microscopy (TEM). Stability of bioreduced silver nanoparticles was analyzed using UV–vis absorption
spectra, and their antimicrobial activity was screened against both gram-negative and gram-positive microorganisms. It was
observed that O. sanctum leaf extract can reduce silver ions into silver nanoparticles within 8 min of reaction time. Thus, this method can be used
for rapid and ecofriendly biosynthesis of stable silver nanoparticles of size range 4–30 nm possessing antimicrobial activity
suggesting their possible application in medical industry. 相似文献
2.
Run-Ping Jia Chun-fa Ou-Yang Yong-Sheng Li Jun-He Yang Wang Xia 《Journal of nanoparticle research》2008,10(1):215-219
For the first time, a newly luminescent nanomaterial, monoclinic wolframite-type HgWO4 nanorods (diameter: ∼200 nm; length: ~2000 nm) are prepared by hydrothermal method together with ultrasonic technique. Fluorescent
(FL) and UV–Vis results both show that for HgWO4, ultrasonic irradiation procedure will change its optical behaviors greatly. When the crystals become into nanorods, the
fluorescent emitting peaks (365 and 495 nm) shift to central region, and finally form a wider one at 435 nm. Similar results
of UV–visible absorption peaks are observed for these two products. FTIR spectra further characterize their structure. All
above unique optical performances might result from both small sizes caused by ultrasonic irradiation procedure and involvement
of incompact d10 electrons. Moreover, possible synthesis mechanisms of HgWO4 nanorods are also investigated. 相似文献
3.
Ling Huang Maolin L. Zhai Dewu W. Long Jing Peng Ling Xu Guozhong Z. Wu Jiuqiang Q. Li Genshuan S. Wei 《Journal of nanoparticle research》2008,10(7):1193-1202
The silver nanoparticles (AgNPs) were synthesized in an alkalic aqueous solution of silver nitrate (AgNO3)/carboxymethylated chitosan (CMCTS) with ultraviolet (UV) light irradiation. CMCTS, a water-soluble and biocompatible chitosan
derivative, served simultaneously as a reducing agent for silver cation and a stabilizing agent for AgNPs in this method.
UV–vis spectra and transmission electron microscopy (TEM) images analyses showed that the pH of AgNO3/CMCTS aqueous solutions, the concentrations of AgNO3 and CMCTS can affect on the size, amount of synthesized AgNPs. Further by polarized optical microscopy it was found that
the CMCTS with a high molecular weight leads to a branch-like AgNPs/CMCTS composite morphology. The diameter range of the
AgNPs was 2–8 nm and they can be dispersed stably in the alkalic CMCTS solution for more than 6 months. XRD pattern indicated
that the AgNPs has cubic crystal structure. The spectra of laser photolysis of AgNO3/CMCTS aqueous solutions identified the early reduction processes of silver cations (Ag+) by hydrated electron formed by photoionization of CMCTS. The rate constant of corresponding reduction reaction was 5.0 × 109 M−1 s−1. 相似文献
4.
Metallic gold nanoparticles have been synthesized by the reduction of chloroaurate anions [AuCl4]− solution with hydrazine in the aqueous starch and ethylene glycol solution at room temperature and at atmospheric pressure.
The characterization of synthesized gold nanoparticles by UV–vis spectroscopy, high resolution transmission electron microscopy
(HRTEM), electron diffraction analysis, X-ray diffraction (XRD), and X-rays photoelectron spectroscopy (XPS) indicate that
average size of pure gold nanoparticles is 3.5 nm, they are spherical in shape and are pure metallic gold. The concentration
effects of [AuCl4]− anions, starch, ethylene glycol, and hydrazine, on particle size, were investigated, and the stabilization mechanism of Au
nanoparticles by starch polymer molecules was also studied by FT-IR and thermogravimetric analysis (TGA). FT-IR and TGA analysis
shows that hydroxyl groups of starch are responsible of capping and stabilizing gold nanoparticles. The UV–vis spectrum of
these samples shows that there is blue shift in surface plasmon resonance peak with decrease in particle size due to the quantum
confinement effect, a supporting evidence of formation of gold nanoparticles and this shift remains stable even after 3 months. 相似文献
5.
Ag@TiO2 core-shell structured particles of nano-size dimensions have been successfully prepared via a one-step way, which has proved quite effective in procuring stable colloids. Transmission electron microscopy (TEM) was employed to characterize the core size and the shell thickness, which typically were 20~40 nm and ~2 nm, respectively. X-ray diffraction (XRD) indicated the existence of silver. Optical absorption dependence on core size and synthetic temperature has been explored by UV–Vis absorption spectroscopy. Finally, the interesting titanium dioxide nanobubbles with silver core leached out by a unique means, were studied, which consequently proved the core-shell structure of the prepared nanoparticles, confirming the TEM observation. 相似文献
6.
Avinash Ingle Mahendra Rai Aniket Gade Manisha Bawaskar 《Journal of nanoparticle research》2009,11(8):2079-2085
We report extracellular biosynthesis of silver nanoparticles by Fusarium solani (USM-3799), a phytopathogen causing disease in onion, when challenged with 1 mM silver nitrate (AgNO3). The formation of nanoparticles was characterized by visual observation followed by UV–Vis spectrophotometric analysis,
which showed a peak at about 420 nm, which is very specific for silver nanoparticles. Further analysis carried out by Fourier
Transform Infrared Spectroscopy (FTIR), provides evidence for the presence of proteins as capping agent, which helps in increasing
the stability of the synthesized silver nanoparticles. Transmission Electron Microscopy (TEM) investigations confirmed that
silver nanoparticles were formed. The synthesized silver nanoparticles were found to be polydispersed, spherical in the range
of 5–35 nm with average diameter of 16.23 nm. Extracellular synthesis of nanoparticles could be highly advantageous from the
point of view of synthesis in large quantities and easy downstream processing. 相似文献
7.
Miguel A. Aguilar-Méndez Eduardo San Martín-Martínez Lesli Ortega-Arroyo Georgina Cobián-Portillo Esther Sánchez-Espíndola 《Journal of nanoparticle research》2011,13(6):2525-2532
Colloidal silver nanoparticles were synthesized by reducing silver nitrate solutions with glucose, in the presence of gelatin
as capping agent. The obtained nanoparticles were characterized by means of UV–Vis spectroscopy, transmission electron microscopy
(TEM), and Fourier transform infrared (FTIR) spectroscopy. The response surface methodology (RSM) was also used to determine
the influence of the variables on the size of the nanoparticles. The antifungal activity of the silver nanoparticles was evaluated
on the phytopathogen Colletotrichum gloesporioides, which causes anthracnose in a wide range of fruits. The UV–Vis spectra indicated the formation of silver nanoparticles preferably
spherical and of relatively small size (<20 nm). The above-mentioned was confirmed by TEM, observing a size distribution of
5–24 nm. According to RSM the synthesis variables influenced on the size of the silver nanoparticles. By means of FTIR spectroscopy
it was determined that gelatin, through their amide and hydroxyl groups, interacts with nanoparticles preventing their agglomeration.
The growth of C. gloesporioides in the presence of silver nanoparticles was significantly delayed in a dose dependent manner. 相似文献
8.
Uğur Tamer İsmail H. Boyacı Erhan Temur Adem Zengin İlker Dincer Yalçın Elerman 《Journal of nanoparticle research》2011,13(8):3167-3176
The preparation and application of rod-shaped core–shell structured Fe3O4–Au nanoparticles for immunomagnetic separation and sensing were described for the first time with this study. To synthesize
magnetic gold nanorod particles, the seed-mediated synthetic method was carried out and the resulting nanoparticles were characterized
with transmission electron microscopy (TEM), ultraviolet visible spectroscopy (UV–Vis), energy-dispersive X-ray (EDX), and
X-ray diffraction (XRD). Magnetic properties of the nanoparticles were also examined. Characterization of the magnetic gold
nanorod particles has proven that the resulting nanoparticles were composed of Fe3O4 core and the gold shell. The rod-shaped gold-coated iron nanoparticles have an average diameter of 16 ± 2 nm and an average
length of about 50 ± 5 nm (corresponding aspect ratio of 3). The saturation magnetization value for the magnetic gold nanorod
particles was found to be 37 emu/g at 300 K. Rapid and room temperature reaction synthesis of magnetic gold nanorod particles
and subsequent surface modification with E. coli antibodies provide immunomagnetic separation and SERS application. The analytical performance of the SERS-based homogenous
sandwich immunoassay system with respect to linear range, detection limit, and response time is also presented. 相似文献
9.
The green synthesis of metallic nanoparticles paved the way to improve and protect the environment by decreasing the use of toxic chemicals and eliminating biological risks in biomedical applications. Plant mediated synthesis of metal nanoparticles is gaining more importance owing to its simplicity, rapid rate of synthesis of nanoparticles and eco-friendliness. The present article reports an environmentally benign and unexploited method for the synthesis of silver nanocatalysts using Trigonella foenum-graecum seeds, which is a potential source of phytochemicals. The UV–visible absorption spectra of the silver samples exhibited distinct band centered around 400–440 nm. The major phytochemicals present in the seed extract responsible for the formation of silver nanocatalysts are identified using FTIR spectroscopy. The report emphasizes the effect of the size of silver nanoparticles on the degradation rate of hazardous dyes, methyl orange, methylene blue and eosin Y by NaBH4. The efficiency of silver nanoparticles as a promising candidate for the catalysis of organic dyes by NaBH4 through the electron transfer process is established in the present study. 相似文献
10.
Qidong Zhao Xinyong Li Ning Wang Yang Hou Xie Quan Guohua Chen 《Journal of nanoparticle research》2009,11(8):2153-2162
Highly ordered TiO2 nanotube arrays were successfully fabricated using ethanol and water mixture electrolytes (40 vol% ethanol and 0.2 wt% hydrofluoric
acid) by a facile electrochemical anodization method. The as-prepared nanotube arrays were grown perpendicular to the titanium
substrate with about 90 nm in diameter, 20 nm in wall thickness, and around 500 nm in length. The formation mechanism of the
samples is briefly discussed. A blue shift in the spectrum of UV–Vis absorption was observed with respect to a piece of the
sol–gel derived TiO2 film. Moreover, photocurrent response and photoelectrocatalytic degradation of methyl orange under ultraviolet light irradiation
were adopted to evaluate the photoelectrocatalytic properties of the TiO2 nanotube arrays. We demonstrate that the highly ordered TiO2 nanotube arrays possess much better photoelectrocatalytic activity than the sol–gel derived TiO2 film and good stability. 相似文献
11.
Maleic anhydride was grafted by long-chain alcohols (1-hexadecanol, 1-octadecanol) to amphiphilic mono-L cis-butene dicarboxylates (L = hexadecyl, octadecyl), i.e., MAH, MAO, respectively. Subsequently, corresponding amphiphilic cerium
complexes with these two mono-L cis-butene dicarboxylate ligands (Ce(L')3, L'= MAH, MAO) were synthesized and behaved as the precursors to prepare CeO2 nanoparticles for both of which can form nanosized micelle-like aggregates by special self-assembly in the wet chemical process.
The nanoparticles were further characterized by Fourier transform-infrared spectroscopy (FTIR), Diffuse reflectance ultraviolet-visible
spectra (DRUVS), scanning electron microscope (SEM), transmission electron microscope (TEM), and x-ray diffraction (XRD).
Both the CeO2 nanoparticles are in a cubic fluorite structure and present regular and well-dispersion club-like morphology with average
particle size in the range of 40–70 nm. Besides, the strong ultraviolet–visible absorption for these CeO2 nanoparticles can be found at the long-wavelength ultraviolet to visible region of 200–500 nm. 相似文献
12.
P. K. Khanna Deepti Kulkarni Rupinder K. Beri 《Journal of nanoparticle research》2008,10(6):1059-1062
Reduction of silver myristate (AgMy) under mild thermal reaction conditions in a dipolar aprotic solvent i.e. N, N-dimethylformamide (DMF) has been carried out. UV–visible absorption measurements of dried and re-dispersible brown flocculants
showed broad features of surface plasmon resonance (SPR) due to silver nanoparticles. The freshly isolated particles showed
absorption bands at 414 and 485 nm, respectively, due to inter-particle coupling or clustering of silver ions and silver atoms.
X-ray diffraction (XRD) pattern of fcc zero-valent silver resulted in crystallite size of about 10 nm. Scanning electron microscopy
(SEM) revealed formation of rod shaped silver with increasing reaction temperature. Thermal analysis (TGA) showed about 10%
weight loss due to organic capping. 相似文献
13.
Jun Pan Baojuan Xi Jingfa Li Yan Yan Qianwen Li Yitai Qian 《Journal of nanoparticle research》2011,13(8):3535-3543
We report a new morphology of wurzite cadmium sulfide with nanoparticles decorated on rod-bundle structures, which were synthesized
via calcinations of an inorganic/organic composite at 400 °C in air. The composite was hydrothermally synthesized at 180 °C
using thioglycolic acid (TGA) and cadmium acetate as starting materials. The structure, composition, and morphology of the
prepared material were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope,
FT-IR spectrometry, photoluminescence spectrometry, and UV–visible spectrometry. Results indicated that the composite could
be defined as CdS 0.65/Cd–TGA0.35. X-ray diffraction revealed that the annealed product is CdS with wurtizite phase. The diameter of the rod is about 150–400 nm
and the length from the top to the bottom of the decorated nanoparticle is about 100 nm. The composite showed high intensity
of photoluminescence with similar peak position, compared to that of wurtzite CdS, because of the structure defects. 相似文献
14.
In this work, the fungus Penicillium was used for rapid extra-/intracellular biosynthesis of gold nanoparticles. AuCl4
− ions reacted with the cell filtrate of Penicillium sp. resulting in extracellular biosynthesis of gold nanoparticles within 1 min. Intracellular biosynthesis of gold nanoparticles
was obtained by incubating AuCl4
− solution with fungal biomass for 8 h. The gold nanoparticles were characterized by means of visual observation, UV–Vis absorption
spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive
X-ray spectroscopy (EDX). The extracellular nanoparticles exhibited maximum absorbance at 545 nm in UV–Vis spectroscopy. The
XRD spectrum showed Bragg reflections corresponding to the gold nanocrystals. TEM exhibited the formed spherical gold nanoparticles
in the size range from 30 to 50 nm with an average size of 45 nm. SEM and TEM revealed that the intracellular gold nanoparticles
were well dispersed on the cell wall and within the cell, and they are mostly spherical in shape with an average diameter
of 50 nm. The presence of gold was confirmed by EDX analysis. 相似文献
15.
Rati Ranjan Nayak Nilotpala Pradhan Debadhyan Behera Kshyama Madhusikta Pradhan Srabani Mishra Lala Behari Sukla Barada Kanta Mishra 《Journal of nanoparticle research》2011,13(8):3129-3137
An eco-friendly microbial method for synthesis of silver colloid solution with antimicrobial activity is developed using a
fungal strain of Penicillium purpurogenum NPMF. It is observed that increase in concentration of AgNO3 increases the formation of silver nanoparticle. At 5 mM concentration highly populated polydispersed nanoparticles form.
Furthermore, change in pH of the reaction mixture leads to change in shape and size of silver nanoparticles. At lower pH two
peaks are observed in the absorption spectra showing polydispersity of nanoparticles. However, highly monodispersed spherical
nanoparticles of 8–10 nm size form with 1 mM AgNO3 concentration at pH 8. Antimicrobial activity of nanoparticles is demonstrated against pathogenic gram negative bacteria
like Escherichia coli and Pseudomonas aeruginosa, and gram positive bacteria like Staphylococcus aureus. The antimicrobial activity of silver nanoparticles obtained at different initial pH show strong dependence on the surface
area and shape of the nanoparticles. 相似文献
16.
U?ur?Tamer Yusuf?Gündo?du ?smail?Hakk??Boyac? Kadir?Pekmez 《Journal of nanoparticle research》2010,12(4):1187-1196
The production of monodispersed magnetic nanoparticles with appropriate surface modification has attracted increasing attention
in biomedical applications including drug delivery, separation, and purification of biomolecules from the matrices. In the
present study, we report rapid and room temperature reaction synthesis of gold-coated iron nanoparticles in aqueous solution
using the borohydride reduction of HAuCl4 under sonication for the first time. The resulting nanoparticles were characterized with transmission electron microscopy
(TEM), electron spectroscopy for chemical analysis (ESCA), ultraviolet visible spectroscopy (UV–Vis), and X-ray diffraction
(XRD). Surface charges and magnetic properties of the nanoparticles were also examined. The pattern of Fe3O4 nanoparticles is face centered cubic with an average diameter of 9.5 nm and the initial reduction of gold on the surface
of Fe3O4 particles exhibits uniform Fe3O4–Au nanoparticles with an average diameter of 12.5 nm. The saturation magnetization values for the uncoated and gold-coated
Fe3O4 nanoparticles were found to be 30 and 4.5 emu/g, respectively, at 300 K. The progression of binding events between boronic
acid terminated ligand shell and fructose based on the covalent bonding interaction was measured by absorbance spectral changes.
Immunomagnetic separation was also performed at different E. coli concentration to evaluate capturing efficiency of resulting nanoparticles. Immunomagnetic separation percentages were varied
in a range of 52.1 and 21.9% depend on the initial bacteria counts. 相似文献
17.
A simple ultrasound assisted precipitation method with addition of glycosaminoglycans (GAGs) is proposed to prepare stable
hydroxyapatite (HAP) nanoparticles suspension from the mixture of Ca(H2PO4)2 solution and Ca(OH)2 solution. The product was characterized by XRD, FT-IR, TEM, HRTEM and particle size, and zeta potential analyzer. TEM observation
shows that the suspension is composed of 10–20 nm × 20–50 nm short rod-like and 10–30 nm similar spherical HAP nanoparticles.
The number-averaged particle size of stable suspension is about 30 nm between 11.6 and 110.5 nm and the zeta potential is
−60.9 mV. The increase of stability of HAP nanoparticles suspension mainly depends on the electrostatic effect and steric
effect of GAGs. The HAP nanoparticles can be easily transported into the cancer cells and exhibit good potential as gene or
drug carrier system. 相似文献
18.
Cherng-Yuh Su Hsuan-Ching Lin Tsung-Kun Yang Chung-Kwei Lin 《Journal of nanoparticle research》2010,12(5):1755-1763
With the use of a modified plasma arc gas condensation technique and control of the processing parameters, namely, plasma
current and chamber pressure, we synthesized tungsten oxide nanomaterials with aspect ratios ranging from 1.1 (for equiaxed
particles with the length and width of 48 nm and 44 nm, respectively) to 12.7 (for rods with the length and width of 266 nm
and 21 nm, respectively). The plasma current and chamber pressure, respectively, ranged from 70 to 90 A and from 200 to 600 Torr.
We then characterized the tungsten oxide nanomaterials by means of X-ray diffraction, high-resolution transmission electron
microscope, UV–visible spectroscope, and photoluminescence (PL) spectroscope. Experimental results show that equiaxed tungsten
oxide nanoparticles were produced at a relatively low plasma current of 70 A, whereas nanorods were produced when plasma currents
or chamber pressures were increased. All of the as-prepared tungsten oxide nanomaterials exhibited a WO2.8 phase. Compared to the nanoparticles, the nanorods exhibited unique properties, such as a redshift in the UV–visible spectrum,
a blue emission in PL spectrum, and a good performance in field emission. With respect to the field emission, the turn-on
voltage for WO2.8 nanorods was found to be as low as 1.7 V/μm. 相似文献
19.
Haijiao Su Liqiang Jing Keying Shi Changhao Yao Honggang Fu 《Journal of nanoparticle research》2010,12(3):967-974
Nanosized LaFeO3 with large specific surface area has been successfully synthesized by an impregnation process, with mesoporous silica SBA-16
as hard template and corresponding metal nitrates as La and Fe resources, and the resulting LaFeO3 is also characterized by thermogravimetry–differential thermal analysis (TG–DTA), X-ray diffraction (XRD), N2 adsorption–desorptions, Brunauer Emmett Teller (BET) technique, transmission electron microscopy (TEM), X-ray photoelectron
spectroscopy (XPS), UV–visible diffuse reflection spectrum (UV–Vis DRS), and surface photovoltage spectroscopy (SPS). It is
found that, compared with that prepared by the conventional citrate method, the as-prepared LaFeO3 with 20-50 nm particle size has remarkable large specific surface area, even still with the surface area as large as about
85 m2 g−1 after calcination at 800 °C, which is attributed to its mesoporous structure as well as the small particle size. During the
photocatalytic degradation of Rhodamine B solution under visible irradiation, all the LaFeO3 samples obtained are superior to P25 TiO2, and the activity becomes high with increasing calcination temperature. It is revealed that the excellent photocatalytic
performance is mainly ascribed to the large surface area and high photogenerated charge separation rate. 相似文献
20.
G. A. Martínez-Castañón N. Niño-Martínez F. Martínez-Gutierrez J. R. Martínez-Mendoza Facundo Ruiz 《Journal of nanoparticle research》2008,10(8):1343-1348
Silver nanoparticles with different sizes (7, 29, and 89 nm mean values) were synthesized using gallic acid in an aqueous
chemical reduction method. The nanoparticles were characterized using transmission electron microscopy (TEM), dynamic light
scattering (DLS), X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis) absorption spectroscopy; the antibacterial activity
was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to
the National Committee for Clinical Laboratory Standards. From the microscopies studies (TEM) we observed that silver nanoparticles
have spherical (7 and 29 nm) and pseudospherical shape (89 nm) with a narrow size distribution. The sizes of the silver nanoparticles
were controlled by varying some experimental conditions. It was found that the antibacterial activity of the nanoparticles
varies when their size diminishes. 相似文献