AgNO3 Solution Research Articles

Facile fabrication of Au-Ag alloy nanoparticles on filter paper: Application in SERS based swab detection and multiplexing

Facile fabrication of flexible substrates containing high concentration of nanoparticles (NPs) is very promising owing to their capability of swab-based surface-enhanced Raman scattering (SERS) trace detection. However, the background signal of the substrate could compromise the trace-detection capabilities. Moreover, the presence of fluorescent molecules may result in intense fluorescence background which could overshadow the Raman peaks. Herein, we demonstrate that the surfactant-free bimetallic (Ag and Au) NPs, synthesized directly on the filter paper, are very effective in reducing the background signal in SERS-based trace detection. Simple soaking of filter paper in a mixture of HAuCl4 and AgNO3 solution, and its immediate drying and reduction produces Au-Ag alloy NPs on the filter paper. Interestingly, the substrates are very effective in quenching the background fluorescence of both filter paper and the analyte, thereby effectively detecting the SERS signature of the fluorescent molecules. In particular, Rhodamine6G (R6G) concentrations down to 10−10 M were detected under resonance excitation, both by solution drying and swabbing. The swab detection of ammonium nitrate, which is usually used in homemade explosives, was also demonstrated. Moreover, owing to the fluorescence quenching properties, the Au-Ag alloy substrates (AuAgS) were able to carry out the swab-based multiplex-detection of crystal violet (CV), Brilliant Cresyl Blue (BCB), and R6G upon resonance excitation of R6G. Finally, the substrates have shown good reproducibility, stability, and signal uniformity. This verifies the potential of AuAgS for real-world trace-detection applications.

Effect of Silver Nanoparticles Prepared from Saraca asoca Leaf Extract on Morphological, Functional, Mechanical, and Antibacterial Properties of Rice Starch Films

AbstractThis study aims to evaluate functional properties of rice starch‐based nanocomposite (NC) films. Silver nanoparticles (SNP) are synthesized using Saraca asoca leaf extract and found to be spherical with diameters ranging between 27 and 45 nm. The SNP solution is added at three different levels: 50, 100, and 150 mL to filmogenic solution (150 mL) and these films are designated as SNP‐50, SNP‐100, and SNP‐150, respectively. In addition to a control film, two more films are made by adding AgNO3 solution (150 mL) and plant extract (150 mL) into filmogenic solutions. Addition of SNP improves tensile strength and decreases elongation at break of rice starch films. NC films show enhanced UV–vis light barrier properties due to increased color intensity and opacity. SNP added films exhibit lower water solubility, water holding capacity, and water vapor permeability. Scanning electron microscopy suggests that control film, SNP‐50, and SNP‐100 have the smoothest surfaces in comparison to all films. SNP incorporation delays biodegradation of films. Silver nanoparticles in the form of colloid, filmogenic solution, and even as discrete films show excellent antibacterial activity against common food pathogens. The SNP concentration significantly correlates (R2 = 0.62–0.96) to the functional properties of films.

Effect of hydrothermal treatment of titanium in high concentration of AgNO 3 solution on surface morphology and roughness.

Development of silver (Ag) modified titanium (Ti) as an antibacterial dental implant has recently been growing. Ag demonstrated an excellent antibacterial property without the risk of bacterial resistance. Hydrothermal treatment using AgNO 3 solution is one of the facile and promising methods to modify Ti surface with Ag. However, the effect of high AgNO 3 concentration and the absent of a toxic reduction agent has not been clearly studied. In this study, Ti surface was hydrothermally treated in 0.01 mol/L and 0.1 mol/L AgNO 3 solutions at 150 oC for 24 hours. Analysis of surface morphology using scanning electron microscopy with energy dispersive X-ray analysis suggested the formation of non-homogenous Ag coating with a tendency to be aggregated and thicken with the increase of AgNO 3 concentration. The Ag coating deposited on Ti surface were composed of mainly metallic and some oxide forms. Surface roughness of all AgNO 3 treated Ti surface was comparable based on the analysis of surface roughness parameter. In conclusion, hydrothermal treatment of Ti surface in solely AgNO 3 solution at high concentration produced non-homogenous Ag coating on its surface without significantly changed surface roughness. Keywords: Silver nitrate, titanium, hydrothermal, surface morphology, roughness.

Development of Chitosan Silver Nanocomposites: Its Characteristic Study and Toxicity Effect against 3T3-L1 Cell Line

Nanocomposite from the natural source is opened a wide area for the researchers to find a natural remedy to replace the chemicals or harmful products in all the fields of agricultural, food and medical fields. Here the biopolymer (chitosan) was extracted from the two white rot fungi of Pleurotus floridanus and Pleurotus djamor, and biologically synthesized with 1mM AgNO3 solution. Synthesized chitosan nanocomposite was characterized with UV-Visible study, FTIR, FESEM, XRD, EDAS for the confirmation based upon the peaks, functional group, crystalline nature, size, morphology and the percentage of elements respectively. Toxicity study was carried out using 3T3 L1 (Mouse embryo fibroblast Cell Line) normal Cell Line to find out the cytotoxicity effect of the chitosan nanocomposite and found that the nanocomposites were non toxic to the Cell Line.

Recovery of Model Pharmaceutical Compounds from Water and Organic Solutions with Alginate-Based Composite Membranes.

In this work, we combined the non-solvent induced phase separation (NIPS) and further cross-linking by cations towards the preparation of nanofiltration membranes based on sodium alginate, a biodegradable, natural polymer. Acetone, ethanol, toluene, and hexane were used as non-solvents, and cations of calcium, silver, and aluminum—for polymer cross-linking, respectively. Results showed the precipitation strength of non-solvent played a noticeable role in the membrane’s performance; for instance, the toluene permeability changed by four orders of magnitude with the decrease of precipitation strength of the non-solvent: acetone (Ptoluene = 0.1 kg∙m−2∙h−1∙bar−1) < ethanol (3 kg∙m−2∙h−1∙bar−1) < hexane (41 kg∙m−2∙h−1∙bar−1) < toluene (415 kg∙m−2∙h−1∙bar−1). It was shown that simultaneous precipitation and crosslinking in aqueous solutions AlCl3 or AgNO3 must be used in the preparation of alginate membranes for the highly selective recovery of pharmaceutical compounds from organic media. These membranes show rejection R = 90–93% of substances with MW = 626 g/mol and ethanol permeability PEtOH = 1.5–2.5 kg∙m−2∙h−1∙bar−1. For the highly selective recovery of pharmaceutical compounds from water, the method of obtaining membranes must be changed. Precipitation in toluene and then crosslinking in aqueous solutions of AlCl3 or AgNO3 must be used sequentially instead of simultaneous precipitation and crosslinking in aqueous solutions of the same inorganic salts. The permeability of such membranes varied from 0.44 to 7.8 kg∙m−2∙h−1∙bar−1 depending on the crosslinking cation in the alginate. The rejection of model substances with MW 350 and 626 g/mol were on the level of 99%. Alginate membranes can be used to solve separation problems in the pharmaceutical field, for example, to isolate antibiotics from their extractants and remove the same antibiotics from aqueous pharmaceutical waste to prevent their accumulation in the environment and the emergence of resistant genes and bacteria.

Cytotoxicity of Silver Nanoparticles Synthesized With the Assistant of Microwave

Silver nanoparticles (AgNPs) are broadly designed for various application. In the current research silver nanoparticles (AgNPs) have been examined for their poisonous outcome on human lymphocyte and chicken embryo fibroblast cell line. AgNPs were synthesized by a simple and easy method from AgNO3 solution with glucose exposed to microwave radiation. The typical size of AgNPs were 30 nm with spherical shape. The cells which cultured with diverse concentrations of silver were examined for their viability using MTT assess, a photometric technique to conclude cell metabolism. The results show that the cell viability of the both cell type were diminished significantly (P<0.05) in dosage dependent mode, and the silver nanoparticles presented higher cytotoxicity to CEF than to human lymphocyte at the same concentration and time point.

Temperature-responsive hybrid nanomaterials based on modified halloysite nanotubes uploaded with silver nanoparticles

New temperature-responsive hybrid nanomaterials based on modified halloysite nanotubes (HNTs) containing grafted polymer brushes with silver nanoparticles have been successfully fabricated. We used a three steps process including synthesis of the initiating coatings onto HNTs surface, fabrication of the POEGMA – poly(oligo(ethylene glycol)ethyl ether methacrylate) grafted brushes and synthesis of the silver nanoparticles (AgNPs). The synthesis and properties of hybrid nanomaterials were studied by FT-IR, TGA and DLS methods. It is shown that the introduction of AgNPs, formed from 0.005 M AgNO3 solution leads to a significant reduction of low critical solution temperature (LCST) of the polymer layer from 29.7 to 21.6 °C. The samples fabricated from 0.05 M AgNO3 solution did not evidence a temperature-induced transition, despite of the contents of AgNPs obtained for both solutions are almost identical (≈ 4%w). The presence of AgNPs with sizes of ca. 20 nm was confirmed in the hybrids prepared from both AgNO3 concentrations by UV–vis spectroscopy, and electron microscopy. These temperature-responsive hybrid nanomaterials may be used for conservation of solid substrates, production of advanced medical facemasks, photothermal therapy against microorganisms and tumors etc.

Volume Variation of Sweet Orange (Citrus sinensis) Juice and Peel Extract Toward the Characteristic and Antibacterial Activity of Nanosilver

Biosynthesis of nanosilver by using sweet orange (C. sinensis) as a bioreductor has shown nanosized results. In this research, the effect of volume variation of sweet orange juice and peel extract combination toward the characteristics and antibacterial activity of synthesized nanosilver will be studied. Solution of AgNO3 1 mM was mixed with a combination of sweet orange juice – peel extract with ratios (v/v), 3:0; 1.5:1.5; 1:2; 0.5:2.5 and 0:3 at 60˚C for 45 minutes. The color change of the mixed solution indicated the formation of nanosilver and confirmed by using UV/Vis spectrophotometer and TEM analysis. The results show that the addition of sweet orange juice in combination accelerated the color change of the mixed solution. The characterization of nanosilver with UV/Vis spectrophotometer confirmed SPR peak at 438-459 nm. The stability test showed that nanosilver reduced with sweet orange juice-peel extract 0,5:2,5 (v/v) was stable and had inhibition diameter tested by the diffusion method against S.aureus (19.50 mm) and S.epidermidis (18.09 mm), indicates a moderate inhibition. Its TEM analysis confirmed the particle's size of about 30-56 nm with spherical form.Keywords: nanosilver, biosynthesis, Citrus sinensis, characteristic, antibacterial activity

Antibacterial textiles which impregnated silver nanoparticles prepared via green synthesis by Fusarium oxysporum BNT-02

Silver nanoparticles can be prepared by using a microorganism. The objectives of the study were to determine the ability of Fusarium oxysporum BNT-02 in reducing silver nitrate solution to silver nanoparticles, to evaluate the effect of variations in treatment of textile materials toward antibacterial activity of textile materials impregnated with silver nanoparticles on Staphylococcus aureus ATCC 25924 and Escherichia coli ATCC 35218. In this study, silver nanoparticle were obtained by reducing the AgNO3 solution by F.oxysporum BNT-02. Coating of silver nanoparticles on textile materials was carried out by inserting sterile textile material into silver nanoparticle and shaking then drying. The textile material modified with silver nanoparticles was characterized for antibacterial activity against S.aureus ATCC 25924 and E.coli ATCC 35218. The inhibition zone to determine antibacterial activity was observed every 6 hours for 48 hours of incubation time. The inhibition zone data was analyzed using ANCOVA and t-test. The results showed that F.oxysporum BNT-02 can be used as a reducing agent for producing silver nanoparticles. The textile material coated with silver nanoparticles had antibacterial properties against S. aureus ATCC 25924 and E. coli ATCC 35218. Antibacterial activity of textile materials coated with silver nanoparticles on S.aureus ATCC 25924 showed a larger inhibition zone than E.coli ATCC 35218.

Anti-Diabetic Activity of Silver Nanoparticles Synthesized from the Hydroethanolic Extract of Myristica fragrans Seeds.

Myristica fragrans, also known as nutmeg, is a spice that cures various diseases. This study aimed to synthesize silver nanoparticles from a hydroethanolic extract of Myristica fragrans seeds (MFHE) and evaluate their anti-diabetic properties. To MFHE, AgNO3 solution was added and exposed to sunlight to produce silver nanoparticles from hydroethanolic seed extract of Myristica fragrans (MFHENP). The MFHENP was characterized by numerous techniques. UV-visible spectroscopy confirmed the formation of silver nanoparticles by the absorption peak at 430nm. Scanning electron microscopy (SEM) studies revealed the shape and size of the particles at the range of 50-60nm. Energy-dispersive X-ray spectroscopy (EDX) disclosed the presence of silver ions. X-ray diffraction spectrum confirmed the crystalline nature of silver nanoparticles by the peak at 39°. FTIR analysis revealed the functional groups present in MFHE as well as in MFHENP and zeta potential analysis was found to be 14mV. Furthermore, in vitro anti-diabetic activity was investigated. MFHENP showed significant efficiency against the inhibition of alpha-amylase and alpha-glucosidase enzymes and also MFHENP retarded the glucose transport across the membrane which is analyzed by glucose diffusion and glucose uptake assays. Acarbose is used as a standard for all these methods and MFHENP efficiency proves their therapeutic potential for the treatment of diabetes mellitus.

Loading of Silver Nanoparticles onto Silica Sand Surface and Simulating of Heat Dissipation for Therapeutic Heat Applications

To develop the heat storage media for therapeutic heat applications, silver nanoparticles (AgNPs) were loaded onto silica sand surface using chemical reduction method. The thermal properties of these two materials were combined and the loading efficiency was verified by using UV-Visible spectroscopy, Scanning Electron Microscopy (SEM), and X-Ray Diffraction Spectroscopy (XRD). Observation by SEM revealed that the silver nanoparticles were homogeneously immobilized onto the silica sand surface and XRD results confirmed the formation of nanocrystalline silver. The crystallite size calculated by Scherrer formula was about 20 nm. It was also found that the particles increased in size and partially agglomerated when the concentration of AgNO3 solutions increased. Furthermore, to estimate the appropriate quantity of the nanoparticles for heating pad application, the finite element simulation by ANSYS was applied. The simulation results showed that the thermal dissipation of the silica sand was improved after loading of the silver nanoparticles. It was also found that the thermal dissipation increased with the silver proportion but 1.50% of silver concentration are sufficient to provide a significant thermal effect.

Synthesis of the S/AgBr nano/micropowder in DMSO-water system

A new synthesis method of S/AgBr nano/micropowder based on sulfur and silver halide was developed. The nano/micropowder was obtained in the DMSO-water system, in two stages. Initially, sulfur was dissolved in DMSO at 120°C. The resulting solution was cooled to room temperature and separated from sulfur by filtration. Then, pre-prepared water solutions of AgNO3 and NaBr were introduced drop by drop into a sulfur solution in DMSO, at room temperature. The phase composition and structure of the precipitated powdery sediment were studied by X-ray diffraction analysis (XRD) and Raman spectroscopy. Scanning electron microscopy (SEM) was used to study the morphology and particle size. XRD showed the presence of the crystalline phase of AgBr, while the Raman spectra were characterized by the presence of sulfur and AgBr peaks. The SEM results showed that the S/AgBr is represented by oval, spherical and triangular particles of a homogeneous structure; the particle size was in the range from 300 to 800 nm.

Silver recovery by microbial electrochemical snorkel and microbial fuel cell

In this study, we demonstrate for the first time the use of the microbial electrochemical snorkel (MES) for silver recovery from aqueous solutions. For comparison, identical bioelectrochemical reactors in which the cathodes were connected through a 510 Ω load resistor (MFC) with the bio-anodes of well-acclimated sediment microbial fuel cells were operated at the same other conditions. Three different types of cathodes - silver foil, copper foil, and graphitized paper, were explored for silver recovery from AgNO3 solution. The data obtained show that the operation in MES mode is more advantageous than that in MFC mode in terms of both silver removal and recovery. The XPS analysis has proved that on the silver foil and graphitized paper cathodes the silver is recovered as Ag0 particles, while on the copper foil cathodes mixed Ag-Cu deposits are obtained due to the predominant electroless displacement of Cu by Ag+. The superiority of operation in MES mode was also confirmed by experiments performed with [Ag(S2O3)2]3- - containing solution, simulating exhausted photographic fixer. The total amount of silver was removed from the MES-catholyte for 24 hours, while during the operation in MFC mode a silver removal of 88.2±5.8 % was reached.

Defect-mediated successive ionic layer adsorption and reaction for constructing Sb2Te3/Ag2S heterojunction to boost hydrogen evolution reaction performance

As a sustainable and green technology for producing high-purity hydrogen, hydrogen evolution reaction (HER) has received extensive attention. The development of an electrocatalyst with good HER activity is the key to economic water electrolysis. Here, this work reports a defect-mediated successive ion layer adsorption and reaction method to construct Ag2S/irradiated Sb2Te3 heterojunctions with good HER activity. First, ion irradiation is used to introduce a large number of defects into Sb2Te3. The defective Sb2Te3 is continuously cyclically immersed in AgNO3 solution and Na2S solution. Ag+ and S2- ions are adsorbed on the defect sites of Sb2Te3 and deposited as Ag2S and the heterojunction of Ag2S/irradiated Sb2Te3 is obtained. By this strategy, the electrochemical active surface area of the material is increased, reduces the charge transfer resistance, and improves the hydrophilicity of the material surface, thus exhibiting good HER activity. In this work, ion irradiation is used to regulate the surface defects of materials and then to regulate the growth of heterojunction to achieve the purpose of regulating the properties of material. The heterojunction growth method controlled by defect engineering can be widely used in the preparation of heterojunction materials in other energy and environmental fields.

In situ growth of silver nanoparticles on polydopamine-coated chalcogenide glass tapered fiber for the highly sensitive detection of volatile organic compounds in water

A high-sensitivity Ge-Sb-Se chalcogenide glass (ChG) tapered fiber (TF) sensor based on a polydopamine (PDA)-silver nanoparticle (AgNP) coating structure is proposed for the first time in this study. The influence of PDA coating thickness on sensitivity to p-xylene aqueous solution is investigated by characterizing the immersion time of TF in the dopamine. Experimental results demonstrate that an increased coating thickness results in higher sensitivity. Based on the reduction of Ag ions by catechol groups in PDA, the optimized PDA-coated TF is exposed to the AgNO3 solution to grow in-situ AgNPs on the coating surface. The existence of AgNPs can introduce effective light coupling between the AgNPs and evanescent waves, enhancing the infrared absorption of the molecules. The sensitivity of the PDA-coated sensor functionalized by AgNPs to detect p-xylene is significantly improved to 4.115E-4 a.u./μg/mL, which is 63 times higher than that of the uncoated sensor. Furthermore, the sensor based on the PDA-AgNP structure exhibits a shorter response time and good practical applicability.

Исследование диэлектрических функций слоя наночастиц Ag на кремнии с помощью спектроэллипсометрии и спектрофотометрии

An investigation of the optical characteristics of a layer of Ag nanoparticles deposited from an AgNO3 solution on the surface of single-crystal Si is presented. The measurements were carried out using spectroscopic ellipsometry and spectrophotometry at the same tilt angle and sample probe location in a wide spectral range from 200 to 1700 nm. From the obtained experimental data, the parameters of the Drude-Lorentz model and the complex dielectric function were determined, which was compared with the pseudo-dielectric function. Both dependences revealed resonances of a bulk plasmon near the energy E = 3.8 eV, while a localized plasmon was detected in the pseudo-dielectric function at E = 1.65 eV, and in the dielectric function at E = 1.84 eV.

A green synthetic approach of silver nanoparticles using Premna tomentosa leaf extract and their anti-microbial study

By using eco-friendly ways leaf extract from Premna tomentosa was used in the synthesis of Ag NPs (Silver nanoparticles). The extract acts as stabilizing and also as reducing agent. The AgNO3 solution was used as Silver precursor, formation of reddish-brown coloured solution from colourless solution was clearly visible, thus indicating the nanoparticles formation, even surface Plasmon resonance in UV visible spectroscopy was observed at 434 nm, confirming the Ag nanoparticles. Using microbes like Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus antimicrobial activity studies were studied for the synthesised nanoparticles. Green synthesized Ag nanoparticles showed good antimicrobial activities against all the four microbes.The MIC values ranged from 25 to 100 mg/ml for Pseudomonas aeruginosa indicating more sensitivity. The Bacillus subtilis and Staphylococcus aureus had least sensitivity towards the prepared Premna tomentosa Silver nanoparticles.

Investigation of dielectric functions of a layer of Ag nanoparticles on silicon using spectro-ellipsometry and spectrophotometry

An investigation of the optical characteristics of a layer of Ag nanoparticles deposited from an AgNO3 solution on the surface of single-crystal Si is presented. The measurements were carried out using spectroscopic ellipsometry and spectrophotometry at the same tilt angle and sample probe location in a wide spectral range from 200 to 1700 nm. From the obtained experimental data, the parameters of the Drude-Lorentz model and the complex dielectric function were determined, which was compared with the pseudo-dielectric function. Both dependences revealed resonances of a bulk plasmon near the energy E = 3.8 eV, while a localized plasmon was detected in the pseudo-dielectric function at E = 1.65 eV, and in the dielectric function at E = 1.84 eV. Keywords: dielectric function, Drude-Lorentz model, silver nanoparticles, plasmon, pseudo-dielectric function, spectrophotometry, ellipsometry

Green Synthesis of Silver Nanoparticles from Root Extracts of Rubus ellipticus Sm. and Comparison of Antioxidant and Antibacterial Activity

The fabrication of metal nanoparticles through green synthetic pathways using plant extracts has increased attention due to low cost, benevolent methods, fewer hazardous byproducts, and applications. Silver nanoparticles (AgNPs) were synthesized by reacting to aqueous root extracts of Rubus ellipticus Sm. (RERE) with AgNO3 solution (1 mM) at an ambient condition. The visual change of color from light yellow to reddish brown and the absorption peak at 416‐420 nm in the UV‐visible spectra indicated the formation of AgNPs in the solution. The shifting of the positions in the FTIR spectra indicated the potential role of the functional groups as capping and stabilizing agents. The powder XRD diffractogram exposed the crystalline nature of the nanoparticles. The surface morphology and the elemental composition of the AgNPs were established by the FESEM and EDX analysis. The TEM images revealed the spherical and monodispersed nanoparticles of size ranging from 13.85 to 34.30 nm with an average of 25.20 ± 7.01 nm (n = 10). The biogenic AgNPs showed a better 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity with lower IC50 (13.83 ± 0.33 μg/mL) as compared to that of the RERE with IC50 (15.86 ± 4.14 μg/mL). The synthesized AgNPs showed higher zones of inhibition (ZOI) on the agar well diffusion method against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), and Klebsiella pneumoniae (ATCC 700603). The result of this study highlights the potential benefits of R. ellipticus root extract‐based AgNPs for biomedical practices.

Enhanced Methane Sensing Properties of SnO2 Nanoflowers With Ag Doping: A Combined Experimental and First-Principle Study

Ag-doped SnO2 nanoflowers (NFs) are prepared via a simple one-step hydrothermal method and subsequent Ag-doping using AgNO3 solution as precursors. The crystal structure, morphology and elements of the Ag-doped SnO2 NFs are investigated in detail. The maximal response of Ag-doped SnO2 sensor with 1.0 wt.% Ag doping to 500 ppm methane is increased by a factor of 1.6 as compared to that of pure SnO2 sensor. The long-term stability and the selectivity of the SnO2-based sensor are improved by Ag-doping as well. Meanwhile, pre-adsorption of oxygen molecules on the surface of the SnO2-based substrate is studied in-depth with the method of first-principle calculation. Ag doping lowers adsorption energy for all the adsorption sites, demonstrating a higher adsorption stability of chemisorbed oxygen ions on the Ag-doped SnO2 as compared to the pristine phase. More electron transfer from the semiconductor to the chemisorbed oxygen is revealed by the Mulliken charge analysis and the electron density difference for the Ag-doped SnO2, explaining the better sensitivity of gas sensors based on Ag-doped SnO2 nanostructures as compared to its undoped counterpart.