Synthesis Of Monodispersed Silver Nanoparticles Research Articles

Ginseng root extract-mediated synthesis of monodisperse silver nanoparticles as a fluorescent probe for the spectrofluorometric determination of nilvadipine; Evaluation of remarkable anti-bacterial, anti-fungal and in-vitro cytotoxic activities

Nanoparticles are a boon for humanity because of their improved functionality and unlimited potential applications. Considering this significance, the proposed study introduced a simple, fast and eco-friendly method for synthesis of fluorescent silver nanoparticles (Ag-NPs) using Panax Ginseng root extract as a reducing and capping agent. Synthesis of Ag-NPs was performed in one step within three minutes utilizing microwave irradiation. The resulting Ag-NPs were characterized using various microscopic and spectroscopic techniques such as, Transmission Electron Microscope (TEM), UV/Visible spectroscopy, Fourier Transform Infrared Spectroscopy(FTIR) and Energy Dispersive X-ray analysis (EDX). The prepared Ag-NPs, which act as a fluorescent nano-probe with an emission band at 416 nm after excitation at 331 nm, were used to assay nilvadipine (NLV) spectrofluorimetrically in its pharmaceutical dosage form with good sensitivity and reproducibility. The proposed study is based on the ability of NLV to quantitatively quench the native Ag-NPs fluorescence, forming a ground state complex as a result of static quenching and an inner filter mechanism. The suggested approach displayed a satisfactory linear relationship throughout a concentration range of 5.0 μM − 100.0 μM, with LOD and LOQ values of 1.18 μM and 3.57 μM, respectively. Validation of the suggested approach was examined in accordance with ICH recommendations. In addition, the anti-bacterial and anti-fungal activities of the prepared nanoparticles were investigated, and they demonstrated effective anti-microbial activities and opened a future prospective to combat future antibiotic resistance. Finally, in-vitro cytotoxicity assay of Ag-NPs against normal and cancerous human cell lines was studied using MTT assay. The results proved the potential use of the produced Ag-NPs as an adjunct to anticancer treatment or for drug delivery without significantly harming healthy human cells.

Synthesis of Monodisperse Silver Nanoparticles in Chitosan Solutions

It has been shown that monodisperse silver nanoparticles can be obtained in a chitosan solution. The temperature regime, reaction time, and pH of the reaction medium at which monodisperse silver nanoparticles with an average diameter of 65 nm are formed have been selected. The nanoparticles are potentially usable in medicine. Spectral studies have been performed to clarify the character of the interaction between chitosan and a silver salt. It has been found that not only hydroxyl groups of chitosan, but also its free primary amino groups, are involved in the reduction of silver ions and stabilization of formed nanoparticles.

The synthesis of monodisperse silver nanoparticles with plant extracts.

Plant extracts are known for their antihyperglycemic, antioxidant, antimutagenic, antifungal, anti-inflammatory, antiviral and antibacterial properties. These biological properties make plant extracts interesting surface modifiers of nanoparticles (NPs), which are also known for their unique features. Plant extracts can play a multifunctional role in the synthesis of NPs (i.e. can act as a reducing agent, stabiliser and bioactive compound), which gives additional properties to the final hybrid material. The combination of an extract of natural origin with NPs results in bioconjugates with unique final properties that often may not be obvious. The properties of a bioconjugate depend on both the plant extract (chemical composition, amount, a method of conjugation to NP surface, etc.) and the NPs (type, size, shape, polydispersity, etc.). Syntheses of NPs with plant extract usually lead to polydisperse particles with heterogeneous properties that are difficult to control from a biological point of view. In this paper, we present a synthesis protocol to obtain monodisperse silver nanoparticles (AgNPs) with plant extract. Cacao beans and grape seed extracts were selected as natural sources of polyphenols having biomedical importance (e.g. catechin, tannic acid, epicatechin gallate) and used to synthesise using a chemical reduction method. Syntheses were carried out with different molar ratios of reagents to find the best conditions for obtaining AgNPs that are homogeneous in size and shape. The colloids obtained were characterised with ultraviolet-visible (UV-Vis) spectroscopy, scanning transmission electron microscopy (STEM) and dynamic light scattering (DLS). It was found that syntheses carried out only with plant extract resulted in unstable colloids containing polydisperse nanoparticles. Stable colloids containing spherical monomodal particles were obtained by the incorporation of sodium citrate as an additional reagent in the synthesis mixture. The results obtained clearly indicate the crucial role of sodium citrate in the synthesis of spherical AgNPs of controlled size using plant extracts for biological applications.

Rapid and Green Synthesis of Monodisperse Silver Nanoparticles Using Mulberry Leaf Extract

Abstract A simple, rapid and eco-friendly technique for the preparation of small-sized silver nanoparticles with narrow distribution from 5 nm to 15 nm was developed. Using silver nitrate as silver precursor, and mulberry leaves extract as both capping and reducing agent, silver nanoparticles were obtained at room temperature, without employing any other reducing and capping agents. The formation of silver nanoparticles was observed by the change of color from pale yellow to brown and the UV-vis absorption spectroscopy. The effects of reaction time, temperature, silver nitrate concentration and mulberry leaves extract amount were studied. The silver nanoparticles were characterized by transmission electron microscopy (TEM), UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrate that the obtained metallic nanoparticles are highly crystalline silver nanoparticles with a spherical shape and capped with extract. A possible formation mechanism was proposed. The method in this paper may be extended to synthesize other noble metal nanoparticles using renewable materials as capping and reducing agents.

Facile synthesis of monodisperse silver nanoparticles for screen printing conductive inks

Monodisperse silver nanoparticles with high concentration are successful synthesized by a modified polyol process under a relatively low mass ratio of PVP to AgNO3. The obtained silver nanoparticles with excellent stability and dispersity possess a mean diameter of about 118 nm and the yield reach to 80 wt%. Then, using the as-prepared silver nanoparticles as filler together with other additives, conductive inks were formulated. This kind of conductive ink could be screen-printed on polyimide substrates to obtain a series of electrical conductive circuits. A relatively low resistivity of 8.3 × 10− 6 Ω·cm which was only five times larger than that of bulk silver was achieved under sintering at 220 °C for 30 min under air atmosphere. Meanwhile, the electrical conductive circuits kept outstanding mechanical performance. So this silver nanoparticles filled electrical conductive inks has the potential applications in flexible wearable devices.

Sodium Alginate Mediated Route for the Synthesis of Monodisperse Silver Nanoparticles Using Glucose as Reducing Agents

A simple and environmentally friendly method was developed for preparing colloidal silver nanoparticles in aqueous solutions using silver nitrate, sodium alginate and glucose as silver precursor, capping agents and reducing agents, respectively. The formation of silver nanoparticles was observed by the change of color from colorless to yellow. The silver nanoparticles were characterized by transmission electron microscopy (TEM), UV-visible spectroscopy (UV-vis) and X-ray diffraction (XRD). The TEM images show that the particles are small, well dispersed and spherical in shape with a narrow distribution from 3 nm to 12 nm. The XRD demonstrates that the obtained metallic nanoparticles are single crystalline silver nanoparticles. The effects of the reaction time, the reaction temperature and the concentration of silver ion and reducing agent on the particle size were investigated by the UV-vis spectra. The present process is an excellent candidate for the preparation of silver nanoparticles because it is simple, free-pollutant, inexpensive and easy to perform. The method may be extended to other noble metals, such as Au, Pd and Pt, for medicinal, industrial and technological applications.

Green microfluidic synthesis of monodisperse silver nanoparticles via genetic algorithm optimization

A scalable and green procedure for the microfluidic flow synthesis of monodisperse silver nanoparticles is reported.

In Situ Synthesis of Monodisperse Silver Nanoparticles on Sulfhydryl-Functionalized Poly(glycidyl methacrylate) Microspheres for Catalytic Reduction of 4-Nitrophenol

Immobilization of silver nanoparticles (Ag NPs) to improve monodispersity and recyclability is crucial for applications in nanocatalysts. Herein, a novel protocol for stabilizer-free, effective, and in situ synthesis of Ag NPs on sulfhydryl-functionalized poly(glycidyl methacrylate) microspheres (PGMA-SH) was proposed. Ag NPs of 16.97 ± 3.15 nm were successfully grown on PGMA-SH, and remained monodisperse and stable even after sonication, washing, and long-term storage. Moreover, the Ag NPs on PGMA-SH (Ag NPs@PGMA-SH) composite exhibited excellent catalytic activity with an average normalized activity parameter of 4.38 × 10–3 L·mg–1·s–1 toward the reduction of 4-nitrophenol, which was 1.3–132 times higher than reported in literature. The composite can be easily recycled and showed excellent reusability as a conversion higher than 92% was achieved after 10 cycles. Thus, the preparation of Ag NPs@PGMA-SH has been proven a feasible, straightforward, and effective protocol, which would facilitate the applicat...

Hydrothermal synthesis of silver nanoparticles in Arabic gum aqueous solutions

Finely divided silver nanoparticles were synthesized via the hydrothermal method. Arabic gum (AG) was used as both the reductant and steric stabilizer without any other surfactant. By adjusting the reaction temperature, mass ratio of AG to AgNO3, and reaction time, silver nanoparticles with different morphological characteristics could be obtained. The products were characterized by UV–Vis, FTIR, TEM, SEM, and XRD measurements. It was found that temperature and AG played an important role in the synthesis of mono-disperse silver nanoparticles. Well dispersed and quasispherical silver nanoparticles were obtained under the optimal synthesis conditions of 10 mmol/L AgNO3, m(AG)/m(AgNO3)=1:1, 160 °C and 3 h.

Controlled synthesis of monodisperse silver nanoparticles supported layered double hydroxide catalyst

Monodisperse silver nanoparticles supported layered double hydroxides (Ag NPs–LDH) were preferentially deposited on the outer surfaces of pillared LDH offered a high catalytic activity on alcohol oxidation.

Facile and one-step synthesis of monodisperse silver nanoparticles using gum acacia in aqueous solution

A practical and convenient method for the synthesis of highly stable and small sized silver nanoparticles with a narrow distribution from 2nm to 20nm is reported. Silver nitrate was used as silver precursor and gum acacia was acted as a capping agent as well as a reducing agent. The formation of silver nanoparticles was observed by change of color from light yellow to black green. The silver nanoparticles were characterized by high resolution transmission electron microscopy (HRTEM), UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectra. The HRTEM images showed that the as-synthesized silver fine spherical particles were distributed uniformly. The XRD and HRTEM results demonstrated that the obtained metallic particles were single crystalline silver nanoparticles. FT-IR spectra data suggested that the silver nanoparticles were coated with gum acacia. The effects of the reaction time, the reaction temperature, the amount of gum acacia and the silver nitrate on the particle size were investigated. The silver nanoparticles are stable and hence can be found of practical use in medicine such as antimicrobial materials. The preparation process is simple and environmentally-friendly, which may be extended to other noble metal for other technological applications.

Synthesis of Monodisperse Silver Nanoparticles by Sonolysis of Silver Carboxylates

AbstractMonodisperse, crystalline silver nanoparticles are synthesized by sonolytically assisted decomposition of silver oxalate and oleate precursors in dibenzylether. Oleic acid and oleylamine are used as capping agents. The diameters of the obtained particles vary from 6 to 10 nm depending on the sonification time and the precursor material. The particles are stable in non‐polar media. A 2D and 3D assembly of the as‐prepared nanoparticles is observed. Particle sizes and dispersities are characterized by transmission electron microscopy and image analysis. The decomposition characteristics of the different precursor compounds are investigated using UV–Vis spectroscopy and thermogravimetry.

Metal ion redox potential plays an important role in high-yield synthesis of monodisperse silver nanoparticles

A facile method is developed to prepare monodisperse silver nanoparticles in a much enhanced yield by adding a trace amount of Fe(3+) ions into the reaction of AgNO(3) with oleic acid and oleylamine. We propose that Fe(2+) ions speed up the nucleation and growth of silver nanoparticles due to the electron-transfer between Ag(+) and Fe(2+), in which Fe(2+) is from Fe(3+) reduced by oleylamine.

Simple and green synthesis of monodisperse silver nanoparticles and surface-enhanced Raman scattering activity

We describe a simple and green method for preparing silver nanoparticles with an average diameter in the range from 4.0 nm to 5.0 nm and with the standard deviation as low as 0.3 nm (polydispersity: 5.5%). The pre-synthesized silver oleate precursor in oleic acid was thermally reduced to obtain the monodisperse silver nanoparticles without a size selection procedure. This environmentally friendly chemistry approach requires only three reagents (silver nitrate, sodium oleate and oleic acid) which all come from renewable resources. The average diameter of these nanoparticles can be greatly adjusted by varying reaction time and finely regulated by varying reaction temperature at the same precursor concentration. The nucleation/diffusional growth model can be used to interpret the size and morphology difference of silver nanoparticles synthesized under different conditions. Raman spectra of graphene with and without an active layer of silver nanoparticles were measured to investigate the surface-enhanced Raman scattering properties of the silver nanoparticles. The Raman signal of graphene with an active layer increased by fifteen-fold in comparison to that without an active layer. The surface-enhanced Raman scattering activity can be explained using interparticle coupling induced Raman enhancement.

Synthesis of monodisperse silver nanoparticles and their self-assembly through simple thermal decomposition approach

An easy one phase synthesis of monodisperse silver nanoparticles and their self-assembly has been reported. Thermal decomposition of silver acetate in diphenyl ether in the presence of oleic acid (cis-9-octadecenoic acid) and oleylamine (cis-9-octadecenoic amine) leads to the formation of silver nanoparticles. The amount of organic content present on the surface of Ag nanoparticles affects the self-assembly of nanoparticles. In the presence of oleic acid alone, no self-assembly was observed but the presence of oleyl amine along with oleic acid led to increased organic coating on the surface of silver nanoparticles resulting in the self-assembly (cubic or hexagonal) of monodisperse silver nanoparticles. The silver nanoparticles were characterized by powder X-ray diffraction (XRD), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), CHN analysis, transmission electron microscopy (TEM), selected area electron diffraction (SAED) and UV–visible spectroscopy.

Controlled Synthesis of Uniform Silver Nanospheres

We describe a new route, in which the polyethylene glycol (PEG) is used both as a solvent and reducing reagent and the polymer polyvinglpyrrolidone (PVP) is used as capping agent, for the synthesis of monodisperse silver nanoparticles. Uniform nanospheres with an average diameter of 54 nm can be routinely synthesized in high yield through this approach by using a PVP/AgNO3 molar ratio of 8 at 260 degrees C. Both the reaction temperature and the PVP/AgNO3 molar ratio are crucial for the diameters and size distributions of the nanospheres.

Facile synthesis of monodisperse silver nanoparticles by bio-template of squama inner coat of onion

This paper describes a facile sy]nthetic method for preparing monodisperse silver nanoparticles by bio-template of the squama inner coat of onion. The method is able to make silver nanoparticles with average diameters in the range of 4.6–7.9 nm with narrow size distribution. The important factors in the synthesis of monodisperse silver nanoparticles were discussed. The nanoparticles were characterized by transmission electron microscope, Powder X-ray diffraction and UV-Vis spectroscopy. A possible formation mechanism was also proposed. Because of its simple apparatus, high yield, convenient operation and mild conditions, this synthetic method will have potential application in preparing nanoparticles.