共查询到20条相似文献,搜索用时 15 毫秒
1.
This study described the utility of green analytical chemistry in the synthesis of gelatin‐capped silver, gold and bimetallic gold–silver nanoparticles (NPs). The preparation of nanoparticles was based on the reaction of silver nitrate or chlorauric acid with a 1.0 wt% aqueous gelatin solution at 50°C. The gelatin‐capped silver, gold and bimetallic NPs were characterized using transmission electron microscopy, UV–vis, X‐ray diffraction and Fourier transform infrared spectroscopy, and were used to enhance a sensitive sequential injection chemiluminescence luminol–potassium ferricyanide system for determination of the anticancer drug raloxifene hydrochloride. The developed method is eco‐friendly and sensitive for chemiluminescence detection of the selected drug in its bulk powder, pharmaceutical injections and biosamples. After optimizing the conditions, a linear relationship in the range of 1.0 × 10 –9 to 1.0 × 10 –1 mol/L was obtained with a limit of detection of 5.0 × 10 –10 mol/L and a limit of quantification of 1.0 × 10 ‐9 mol/L. Statistical treatment and method validation were performed based on ICH guidelines. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
2.
Present work demonstrates the simple, chemical free, fast, and energy efficient method to produce reduced graphene oxide (r-GO) solution at RT using visible light irradiation with plasmonic nanoparticles. The plasmonic nanoparticle is used to improve the reduction efficiency of GO. It only takes 30 min at RT by illuminating the solutions with Xe-lamp, the r-GO solutions can be obtained by completely removing gold nanoparticles through simple centrifugation step. The spherical gold nanoparticles (AuNPs) as compared to the other nanostructures is the most suitable plasmonic nanostructure for r-GO preparation. The reduced graphene oxide prepared using visible light and AuNPs was equally qualitative as chemically reduced graphene oxide, which was supported by various analytical techniques such as UV-Vis spectroscopy, Raman spectroscopy, powder XRD and XPS. The reduced graphene oxide prepared with visible light shows excellent quenching properties over the fluorescent molecules modified on ssDNA and excellent fluorescence recovery for target DNA detection. The r-GO prepared by recycled AuNPs is found to be of same quality with that of chemically reduced r-GO. The use of visible light with plasmonic nanoparticle demonstrates the good alternative method for r-GO synthesis. 相似文献
3.
The Actinomycete Gordonia amicalis HS-11 produced orange pigments when cultivated on n-hexadecane as the sole carbon source. When cells of this pigmented bacterium were incubated with 1 mM chloroauric acid (HAuCl 4) or silver nitrate (AgNO 3), pH 9.0, at 25 °C, gold and silver nanoparticles, respectively, were obtained in a cell associated manner. It was hypothesized that the pigments present in the cells may be mediating metal reduction reactions. After solvent extraction and High Performance Liquid Chromatography, two major pigments displaying UV–vis spectra characteristic of carotenoids were isolated. These were identified on the basis of Atmospheric Pressure Chemical Ionization Mass Spectrometry (APCI-MS) in the positive mode as 1′-OH-4-keto-γ-carotene (Carotenoid K) and 1′-OH-γ-carotene (Carotenoid B). The hydroxyl groups present in the carotenoids were eliminated under alkaline conditions and provided the reducing equivalents necessary for synthesizing nanoparticles. Cell associated and carotenoid stabilized nanoparticles were characterized by different analytical techniques. In vitro free radical scavenging activities of cells (control, gold and silver nanoparticle loaded), purified carotenoids and carotenoid stabilized gold and silver nanoparticles were evaluated. Silver nanoparticle loaded cells and carotenoid stabilized silver nanoparticles exhibited improved nitric oxide (NO) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activities compared to their control and gold counterparts. This paper thus reports cell associated nanoparticle synthesis by G. amicalis, describes for the first time the role of carotenoid pigments in metal reduction processes and demonstrates enhanced free radical scavenging activities of the carotenoid stabilized nanoparticles. 相似文献
4.
A novel method of one-step preparation of dual-labeled gold nanoparticle bio-probes was established by the electrostatic adsorption
and the covalent bonding of gold nanoparticles with antibodies and thiol-modified oligonucleotides, respectively. Characterization
of probes, the coverage and activity of antibodies and oligonucleotides on probe surfaces were detected. The results indicated
that the gold nanoparticles labeled with antibodies and oligonucleotides possess good bioactivity and the coverage of oligonucleotide
and antibody on a dual-labeled gold nanoparticle bio-probe was (92 ± 20) and (8 ± 3), respectively. The preparative method
is simple and stable. The dual-labeled gold nanoparticle bio-probes have an application value in detection of ultramicro protein. 相似文献
5.
Methods of myoglobin determination based on electrochemical analysis by means of analysis of electrochemical parameters of
modified electrodes have been proposed. The method of direct detection is based on interaction of myoglobin with anti-myoglobin
with subsequent electrochemical registration of this hemoprotein. The electrode surface was modified by a membrane-like synthetic
didodecyldimethylammonium bromide (DDAB), gold nanoparticles and antibodies to human cardiac myoglobin the electrochemical
reduction of myoglobin heme was registered provided that the antigen (myoglobin) was present in the samples. The reaction
of myoglobin binding to antibodies immobilized on the electrode surface was also registered using electrochemical impedance
spectroscopy. The study of electro analytical characteristics revealed high specificity and sensitivity of the developed method.
The biosensor was characterized by low detection limit and a high working range of the detected concentrations from 17.8 to
1780 ng/ml (from 1 to 100 nM). The method of myoglobin determination based on a signal of gold nanoparticles has also been
proposed. The signal was detected with stripping voltammetry. There was a change in the cathodic peak area and the peak height
of gold oxide reduction for the electrodes with antibodies and the electrodes with the antibody-myoglobin complex. 相似文献
6.
Size- and shape-controlled syntheses of silver and gold nanoparticles have been successfully developed using partially hydrolyzed starch vermicelli templates as green nanoreactors for the growth of nanoparticles. Mung bean vermicelli is of interest due to the higher amylose content and its transparency, allowing the formation of coloured particles on the vermicelli to be observed. The as-prepared silver and gold nanoparticles were characterized by UV–Visible spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The carbonization of as-prepared vermicelli at 200 °C, 300 °C, and 500 °C was carried out to investigate nanoparticles embedded in the starch vermicelli templates. TEM of carbonized samples revealed the interesting patterns of gold nanorods and silver nanowire-liked assemblies along with carbon nanotubes. The carbonization of silver nanoparticles at 500 °C resulted to the loss of starch vermicelli capping nanoparticles and this led to the higher diffusion rate of nanoparticles to generate silver nanodendrites on TEM images. XRD data of carbonized yellow and purple silver nanoparticles revealed the presence of silver nanoparticles and a mixture of silver and silver chloride nanoparticles, respectively. This approach offers a great potential to design new fine structures of vermicelli and utilize its structure as a template for the large-scale synthesis of size- and shape-controlled silver and gold nanoparticles for chemical and biological applications. 相似文献
7.
Leaf extracts of two plants, Magnolia kobus and Diopyros kaki, were used for ecofriendly extracellular synthesis of metallic gold nanoparticles. Stable gold nanoparticles were formed by treating an aqueous HAuCl 4 solution using the plant leaf extracts as reducing agents. UV–visible spectroscopy was used for quantification of gold nanoparticle synthesis. Only a few minutes were required for >90% conversion to gold nanoparticles at a reaction temperature of 95 °C, suggesting reaction rates higher or comparable to those of nanoparticle synthesis by chemical methods. The synthesized gold nanoparticles were characterized with inductively coupled plasma spectrometry (ICP), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), and particle analysis using a particle analyzer. SEM and TEM images showed that a mixture of plate (triangles, pentagons, and hexagons) and spherical structures (size, 5–300 nm) were formed at lower temperatures and leaf broth concentrations, while smaller spherical shapes were obtained at higher temperatures and leaf broth concentrations. 相似文献
8.
Metal nanoparticles (NPs) possessing localized surface plasmon resonance (LSPR) are of high interest for applications in optics, electronics, catalysis, and sensing. The practically important issue is the stability of the LSPR, which often limits the use of some metals due to their chemical reactivity leading to degradation of the NP functionality. In this work, copper NPs of two distinct sizes are produced by magnetron sputtering gas aggregation. This method ensures formation of the particles with high purity and monocrystallinity, enhancing the chemical inertness and providing a superior time stability of the plasmonic properties. Additionally, a simple UV-ozone treatment, which leads to the formation of an oxide shell around the copper NPs, is found to be an efficient method to prevent following gradual oxidation and assure the LSPR stability in ambient atmospheric conditions for periods over 100 days even for small (10–12 nm in diameter) NPs. The obtained results allow for significant improvement of the competitiveness of copper NPs with gold or silver nanostructures, which are traditionally used in plasmonics. 相似文献
9.
Despite the vast research being conducted on the development of biosynthetic procedures, the process is limited owing to the unavailability of modes to control the size and shape of the biosynthesized nanoparticles. In this study, we investigate the size and shape control of gold nanoparticles synthesized by leaf extract of Piper betle (PBE). The effects of various counter ions, temperatures, pH and reaction times on the morphology of gold nanoparticles are also scrutinized. Results from this study indicate that the presence of iodine during biosynthesis leads to the formation of spherical gold nanoparticles and induces the presence of bromine-emanating, truncated nanoplatelets. Spherical nanoparticles are formed with increasing incubation temperature. pH 3 was found to be the optimum for nanoparticles synthesis. The presence of phosphates, sulphates and nitrates increases the productivity of nanoparticles. ICP analysis revealed complete reduction of AuCl 4− ions within 48 h of the reaction. The use of plant extract for rapid synthesis represents a novel and environmentally friendly approach for the fabrication of gold nanoparticles and nanoplatelets, as an alternative to chemical methods. 相似文献
10.
A localized surface plasmon resonance immunoassay has been developed to determine prolactin hormone in human serum samples. Gold nanoparticles were synthesized, and the probe was prepared by electrostatic adsorption of antibody on the surfaces of gold nanoparticles. The pH and the antibody-to-gold nanoparticle ratio, as the factors affecting the probe functions, were optimized. The constructed nanobiosensor was characterized by dynamic light scattering. The sensor was applied for the determination of prolactin antigen concentration based on the amount of localized surface plasmon resonance peak shift. A linear dynamic range of 1–40 ng ml −1, a detection limit of 0.8 ng ml −1, and sensitivity of 10 pg ml −1 were obtained. Finally, the nanobiosensor was applied for the determination of prolactin in human control serum sample. 相似文献
11.
Aptamers are DNA or RNA single-stranded molecules that bind specifically to target molecules with high affinity. Function of nucleic acid aptamers is based on organized tertiary structure of them that is related to primary sequence, length of nucleic acid molecule, and environmental conditions. Herein, a localized surface plasmon resonance (LSPR) nanobioprobe has been developed based on specific aptamer-conjugated gold nanoparticles for rapid detection of methamphetamine. Detection of methamphetamine was studied via monitoring the gold nanoparticles (GNPs) LSPR band alterations in the presence of different concentrations. The covalent conjugation has been confirmed with FT-IR spectroscopy, and size alterations of gold nanoparticles before and after the conjugation state were monitored using dynamic light scattering (DLS) technique. The results show high affinity of aptamer to methamphetamine. Moreover, the results show conjugated aptamer with GNP in different concentrations of methamphetamine that contribute to color changes that is visible with unaided eye. Also, 14 nm LSPR shift was seen after conjugation of aptamer with GNP. Nanoparticle diameter after conjugation with aptamer was increased from 30 to 91 nm and decreased after incubation with methamphetamine (due to folding) from 91 to 84 nm. Detection limit of this designed nanoprobe is 500 nM. Plasmonic nanoparticle-based nanobioprobe is a new field for development of sensitive detection systems. 相似文献
12.
The synthesis of metal nanoparticles by green methods attained enormous attention in recent years due to its easiness, non-toxicity, and eco-friendly nature. In the present study, noble metal nanoparticles such as silver and gold were prepared using an aqueous leaf extract of a medicinal plant, Bauhinia purpurea. The leaf extract performed as both reducing and stabilizing agents for the development of nanoparticles. The formations of silver and gold nanoparticles were confirmed by observing the surface plasmon resonance peaks at 430 nm and 560 nm, respectively, in UV–Vis absorption spectrum. Various properties of nanoparticles were demonstrated using the characterization techniques such as FTIR, XRD, TEM, and EDX. The synthesized silver and gold nanoparticles had a momentous anticancer effect against lung carcinoma cell line A549 in a dose-dependent manner with IC50 values of 27.97 µg/mL and 36.39 µg/mL, respectively. The antimicrobial studies of synthesized nanoparticles were carried out by agar well diffusion method against six microbial strains. Silver and gold nanoparticles were also showed high antioxidant potentials with IC50 values of 42.37 µg/mL and 27.21 µg/mL, respectively; it was measured using DPPH assay. Additionally, the nanoparticles were observed to be good catalysts for the reduction of organic dyes. 相似文献
13.
This paper reports a label-free electrochemical immunosensor for the determination of aflatoxin B1 (AFB1), which is based on a gold electrode modified by a biocompatible film of carbon nanotubes/poly(diallyldimethylammoniumchloride)/Pd–Au nanoparticles (CNTs/PDDA/Pd–Au). The nanocomposite was characterized by transmission electron microscopy and the electrochemical behavior of modified electrodes was investigated by cyclic voltammetry. The CNTs/PDDA/Pd–Au nanocomposites film showed good electron transfer ability, which ensured high sensitivity to detect AFB1 in a range from 0.05 to 25 ng mL −1 with a detection limit of 0.03 ng mL −1 obtained at 3σ (where σ is the standard deviation of the blank solution, n = 10). The proposed immunosensor provides a simple tool for AFB1 detection. This strategy can be extended to any other antigen detection by using the corresponding antibodies. 相似文献
14.
A facile, straightforward, and low-cost method is proposed to synthesize gold@silver@gold core double-shell nanoparticles. The technique is a seed-mediated growth protocol that contains four steps of (1) gold seed synthesis, (2) gold seed growth, (3) silver layer coating through silver salt reduction, and (4) gold layer deposition via gold precursor reduction. The prepared nanoparticles had a narrow size distribution and the average particle size of 28 ± 1 nm. Cysteine was introduced to the nanoparticles solution as a coupling agent to assemble nanoparticles. Aggregation-induced two-photon photoluminescence enhancement of three types assembled nanoparticles, i.e., gold@silver@gold, gold@silver, and gold nanoparticles, was studied. It was observed that the assembled core double-shell nanoparticles presented huge enhancement in two-photon photoluminescence signal in comparison with two other nanoparticles. Moreover, the gold@silver@gold nanoparticle is a stable and biocompatible plasmonic nanosystem. This paper provides a novel candidate for two-photon photoluminescence excitation sensing and imaging for biomedical applications. 相似文献
15.
Biofabrication of nanoparticles via the principles of green nanotechnology is a key issue addressed in nanobiotechnology research. There is a growing need for development of a synthesis method for producing biocompatible stable nanoparticles in order to avoid adverse effects in medical applications. We report the use of simple and rapid biosynthesis method for the preparation of gold nanoparticles using Macrophomina phaseolina (Tassi) Goid, a soil-borne pathogen. The effect of pH and temperature on the synthesis of gold nanoparticles by M. phaseolina was also assessed. Different techniques like UV-Visible Spectroscopy, Transmission Electron Microscopy (TEM), Dynamic light scattering (DLS) measurements, Fourier transform infrared (FTIR), and EDX were used to characterize the gold nanoparticles. The movement of these gold nanoparticles inside Escherichia coli (ATCC11103) along with effect on growth and viability was evaluated. The biogenic gold nanoparticle was synthesized at 37 °C temperature and neutral pH. UV-Visible Spectroscopy, TEM, EDX, and DLS measurements confirm the formation of 14 to 16 nm biogenic gold nanoparticles. FTIR substantiates the presence of protein capping on Macrophomina phaseolina-mediated gold nanoparticles. The non-toxicity of gold nanoparticles was confirmed by the growth and viability assay while the TEM images validated the entry of gold nanoparticles without disrupting the structural integrity of E. coli. Biogenic method for the synthesis of nanoparticles using fungi is novel, efficient, without toxic chemicals. These biogenic gold nanoparticles themselves are nontoxic to the microbial cells and offer a better substitute for drug delivery system. 相似文献
16.
The development of an eco-friendly and reliable process for the synthesis of gold nanomaterials (AuNPs) using microorganisms
is gaining importance in the field of nanotechnology. In the present study, AuNPs have been synthesized by bio-reduction of
chloroauric acid (HAuCl 4) using the fungal culture filtrate (FCF) of Alternaria alternata. The synthesis of the AuNPs was monitored by UV–visible spectroscopy. The particles thereby obtained were characterized by
UV, dynamic light scattering (DLS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, Fourier transform infrared
(FTIR) spectroscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM). Energy-dispersive X-ray study
revealed the presence of gold in the nanoparticles. Fourier transform infrared spectroscopy confirmed the presence of a protein
shell outside the nanoparticles which in turn also support their stabilization. Treatment of the fungal culture filtrate with
aqueous Au + ions produced AuNPs with an average particle size of 12 ± 5 nm. This proposed mechanistic principal might serve as a set
of design rule for the synthesis of nanostructures with desired architecture and can be amenable for the large scale commercial
production and technical applications. 相似文献
17.
A novel potentiometric immunosensor for the detection of adrenal cortical hormones (ACH) has been developed by means of self-assembling
immobilization of adrenal cortical hormone antibody (anti-ACH) on a gold electrode-modified gold nanoparticle (Au) and a thiol-containing
sol–gel network. A cleaned gold electrode was first immersed in a (3-mercaptopropyl)-trimethoxysilane (MPS) sol–gel solution
to assemble a silica sol–gel monolayer, then the silane units were polymerized into a 2D sol–gel network (2D network) by dipping
into aqueous NaOH. The second silane layer was formed by immersion back into the MPS solution overnight, and then the gold
nanoparticles (nanogold) were chemisorbed onto the thiol groups of the second silane layer. Finally, anti-ACH was adsorbed
onto the surface of the gold nanoparticles. The modified process was characterized by electrochemical impedance spectroscopy
(EIS). The detection is based on the change in the potentiometric response before and after the antigen–antibody reaction.
Using nanogold and 3-MPS as substrates, potentiometric detection at room temperature resulted in a pseudolinear detection
range of about 22–1,000 ng mL −1 with a detection limit of 5.2 ng mL −1. Subsequently, several serum samples obtained from medical students with different anxiety extents were analyzed comparing
with the ELISA method, and the results demonstrated that the immunoassay meets the demands of psychological analyses. 相似文献
18.
一种DNA-金纳米粒子导电复合物被成功的制备并应用于癌胚抗原(CEA)的早期检测中。该导电复合物网状结构的制备主要基于DNA中呈负电性的磷酸骨架与带正电荷的金纳米粒子之间的静电自组装技术。测试结果显示,该纳米复合物可以很好的检测癌胚抗原,且检测浓度达到了5ng/mL,从而为癌症的早期检测奠定了基础。 相似文献
19.
Biological systems employing microorganisms have been used as an alternative to conventional chemical techniques for synthesizing gold nanoparticles. In the present study, gold nanoparticles have been synthesized from the supernatant broth (SB) and live cell filtrate (LCF) of the industrially important fungus Penicillium rugulosum. Additionally, potato dextrose broth (PDB) medium which is used for the growth of the fungus has also been able to synthesize gold nanoparticles. The size of the particles has been investigated by Bio-TEM before purification as well as after purification to find the difference in morphology pattern of the nanoparticles. Different characterization techniques like X-ray diffraction (XRD), infra-red (FTIR), X-ray photoelectron (XPS) and UV–vis spectroscopy have been used for analysis of the particles. SB of the fungus has yielded nanoparticles with better morphology and hence further optimization studies were conducted for controlling the size and shape of the above by altering pH and concentration of gold salt. A pH range of 4–6 has favored the synthesis process whereas increasing concentration of gold salt (beyond 2 mM) has resulted in the formation of bigger sized and aggregated nanoparticles. The optimized nanoparticles have been used to conjugate with isolated genomic DNA of bacteria Escherichia coli and Staphylococcus aureus. Visual observation of agarose gel electrophoresis images confirmed the binding of gold nanoparticles (4 μL and 6 μL) with isolated DNA (2 μL) fragments of both the organisms. The slight red shift of the surface plasmon (SP) band and minor aggregations noticed in Bio-TEM images for the DNA conjugated gold nanoparticles indicates that the genomic DNA could stabilize the particles against aggregation owing to negatively charged phosphate backbone. 相似文献
20.
Thin films with tunable optical properties from yellow to metallic were prepared from a monolayer coating of silver nanoparticles (AgNP) onto a polyelectrolyte multilayer (PEM) thin film. The AgNP were synthesized using various concentrations of stabilizing polyelectrolytes leading to a competitive adsorption concept in which AgNP compete with excess polyelectrolytes to coat the cationic PEM top layer. The AgNP were synthesized by chemical reduction of Ag salts using poly(styrene 4-sulfonic acid-co-maleic acid) (PSS-co-MA) as stabilizing agent to produce nanoparticles coated with both a strong acid (sulfonic) and a weak acid (carboxylic) moiety. Although all the nanoparticle solutions displayed a characteristic bright yellow due to the localized surface plasmon band around 420 nm, the monolayer films of nanoparticles obtained after dipping displayed striking different optical properties. When using a high PSS-co-MA content in the solution, a pale-yellow film was obtained which color shifted to orange and metallic when the capping concentration was decreased from 0.25 to 0.001 mM. The optical properties of the AgNP film could be further changed by galvanic replacement of the Ag with gold ions to produce a gold monolayer. These results are interesting to produce surface with tunable catalytic properties, tunable optical properties, or to be used as primer for the metallization of polymeric surfaces. 相似文献
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