Amount Of Silver Nitrate Research Articles

Light-induced ZnO/Ag/rGO bactericidal photocatalyst with synergistic effect of sustained release of silver ions and enhanced reactive oxygen species

Silver nanoparticles (Ag NPs) can effectively address the issue of antibiotic-resistant bacterial infections to reduce the potential toxicity of Ag NPs. Although challenging, it is, therefore, necessary to achieve the sustainable release of Ag+ ions from a finite amount of Ag NPs. This study aims at designing an efficient and benign antimicrobial silver-based ternary composite composed of photocatalysis zinc oxide (ZnO) and reduced graphene oxide (rGO) as a carrier, in which the reactive oxygen species (ROS) excited from ZnO and Ag+ ions released from the Ag NPs cooperate to realize an effective antibacterial activity against E. coli and S. aureus. The constant effective bacterial performance of the ternary photocatalyst with minimum Ag content can be attributed to the increase in the available quantity of ROS, which results from the enhanced separation efficiency of the photogenerated carriers. The proposed system notably realized the long-term sustainable release of Ag+ ions with low concentration for 30 days when compared with an equivalent amount of silver nitrate. Moreover, the use of the composite prevents biotoxicity and silver wastage, and imparts enhanced stability to the long-lasting antibacterial efficacy.

Synthesis and Biological Activity of 5-Aryl-N-{4-[(1,3-thiazol-2-yl)sulfamoyl]phenyl}-1-phenyl-1H-pyrazole-3-carboxamides and Their Salts

The reaction of 4-aryl-2-hydroxy-4-oxo-N-{4-[(1,3-thiazol-2-yl)sulfamoyl]phenyl}but-2-enamides with phenylhydrazine in glacial acetic acid afforded 5-aryl-N-{4-[(1,3-thiazol-2-yl)sulfamoyl]phenyl}-1-phenyl-1H-pyrazole-3-carboxamides. Treatment of the latter with an equimolar amount of silver nitrate in ethanol–DMF (2:1) gave the corresponding silver salts, while 5-aryl-N-{4-[(1,3-thiazol-2-yl)sulfamoyl]phenyl}-1-phenyl-1H-pyrazole-3-carboxamide sodium salts were obtained by reaction with sodium methoxide in methanol–DMF (1:1). The synthesized compounds were tested for analgesic, anti-inflammatory, and antimicrobial activities.

Label-Free SERS Detection of Bovine Serum Albumin Protein Based on Au@Ag Core/Shell Nanobricks

In this study, a simple yet effective protein detection method was established by using bimetallic Au@Ag core-shell nanobrick as SERS active building blocks. The Au@Ag core-shell nanobrick is synthesized by well-defined ‘two-step’ growing method, enabling uniform and controllable silver shell growth on the surface of the gold nanorods induced by surfactant replacement. The thickness of the silver shell can be programmably adjusted by controlling the amount of silver nitrate in the system, which in turn realized the controllable adjustment of the optical properties of Au@Ag core-shell nanobrick. We selected bovine serum albumin as a model protein and established a highly-sensitive assay for label-free SERS detection of protein. The detection limit can reach to as low as 0.5 μg/mL, enabling promising avenue for its clinical application in ultrasensitive biomarker detection.

In Situ Synthesis of a Silver-Containing Superabsorbent Polymer via a Greener Method Based on Carboxymethyl Celluloses.

An antibacterial superabsorbent polymer (SAP) was synthesized by grafting acrylic acid (AA) onto carboxymethyl cellulose (CMC) and mixing with silver particles, with N,N′-methylenebisacrylamide used as a crosslinker and potassium persulfate as an initiator. Silver nanoparticles were produced through the reaction between glucose and silver nitrate. The effects of the amount of silver nitrate added in the polymer on the swelling ratio were investigated and the maximum swelling ratio of the SAP loaded with silver particles in distilled water and in a 0.9 wt % NaCl solution reached 840 g/g and 71 g/g, respectively, when the silver nitrate added was 50 mg. The SAP was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, energy dispersive spectrometry, transmission electron microscopy, and thermogravimetric analysis. Through these analysis methods, it could be seen that the acrylic acid was successfully grafted onto CMC, forming a three-dimensional network structure, with the successful production of silver nanoparticles with sizes ranging from 5 nm to 50 nm. Moreover, the antibacterial properties of the SAP loaded with silver nanoparticles against Staphylococcus aureus and Escherichia coli were investigated and the results show that they became more effective with increasing silver nitrate concentration. The obtained SAP can be useful in developing new antibacterial medical and public health supplies.

The Synthesis and Stability Study of Silver Nanoparticles Prepared by Using <i>p</i>-Aminobenzoic Acid as Reducing and Stabilizing Agent

A study to examine the performance of p-aminobenzoic acid as both reducing agent for silver nitrate to silver nanoparticles (AgNPs) and stabilizing agent for the formed AgNPs has been done. The synthesis of AgNPs was performed by mixing silver nitrate solution as precursor with p-aminobenzoic acid solution and heating it in a boiling water bath. After the solution turned to yellow, the reaction stopped by cooling it in tap water. The formed AgNPs were analyzed by using UV-Vis spectrophotometry to evaluate their SPR absorption in wavelength range of 400–500 nm. The synthesis process was highly depend on the pH, reaction time, and mole ratios of the reactants. The synthesis only occur in pH 11 and at reaction time 30 min, the particle size of the formed AgNPs was 12 ± 7 nm. Longer reaction time increased the reducing performance of p-aminobenzoic acid in AgNPs synthesis but decreased its stabilizing performance. The increase of silver nitrate amount relative to p-aminobenzoic acid in the synthesis increased the reducing and stabilizing performance of p-aminobenzoic acid and the optimum mole ratio between AgNO3 and p-aminobenzoic acid was 5:100 (AgNO3 to p-aminobenzoic acid).

Microwave-Assisted Rapid Preparation of Nano-ZnO/Ag Composite Functionalized Polyester Nonwoven Membrane for Improving Its UV Shielding and Antibacterial Properties.

The cost and efficiency of preparing ZnO/Ag composite functional polyester membrane affect their application, for which a rapid microwave-assisted method was studied for coating ZnO/Ag composite nanoparticles on polyester nonwoven. The surface morphology, crystalline structure, and surface chemistry of the uncoated and coated polyester nonwoven was investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG), respectively. Washing stability, ultraviolet properties, and antibacterial properties of before and after treatment polyester nonwoven were also investigated. The results indicated that Ag/ZnO composite nanoparticles were successfully deposited on polyester nonwoven surface. The amount of silver nitrate added in reaction has an important effect on the morphology and structure of Ag/ZnO composite on the surface of polyester fiber. The washing experiment results show that the ZnO/Ag composite functional polyester nonwoven fabric prepared by this method exhibits good washing durability after 90 min of washing. The results of UV transmission analysis showed that polyester nonwoven has an obvious increase in ultraviolet resistant properties after Ag/ZnO composite coating. When 0.2 g of silver nitrate was added into 100 mL of the reaction solution, the mean ultraviolet protection factor (UPF) of the treated polyester nonwoven reached a maximum of 219.8. The antibacterial results showed that the coated nonwoven against Escherichia coli and Staphylococcus aureus was about 94.5% and 96.6%, respectively, showing very good antibacterial properties.

Integration of Functional Nanomaterials in Biopolymer Composites Using Ionic Liquid Based Methods

In this work, metallic silver nanoparticles were synthesized in linen powders by the process of incipient wetness impregnation. Linen powders with varying concentrations of silver particles were prepared by control of the amount of silver nitrate added during the synthesis. These composite materials were characterized by XPS, SEM, EDS, ATR-IR, and Raman. XPS showed that the silver was predominately zero valent. SEM did not show any distinct silver particles at the limit of the instrument resolution. However, EDX indicated a uniform distribution of silver in all linen powders. The ATR-IR exhibited no significant change in the linen substrate after silver nanoparticle synthesis. Raman spectroscopy of the linen powders displayed significant variability depending upon the amount of silver present. At low silver concentrations, the auto fluorescence of the lignin in the Linen powders dominated the Raman spectrum. At higher silver concentrations, the auto fluorescence declined dramatically and the Raman spectra of the cellulose emerged. At 10 wt % silver, the fluorescence was completely quenched and the cellulose spectrum was significantly enhanced. These results are consistent with the presence of nanoparticles that quench underlying linen fluorescence and give a surface enhanced Raman spectrum of the linen. The linen containing silver nanoparticles were then added to an IL to make an “ink” that was used to print patterns on a cellulose substrate.

Synthesis, characterization, antibacterial activity in dark and in vitro cytocompatibility of Ag-incorporated TiO2 microspheres with high specific surface area.

Postoperative infection associated with medical implants is a devastating complication of orthopedic surgery. Considering the difficulties for the diagnosis and treatment of infection, coating the implant material with antibacterial substances is a promising protocol by which to avoid such an adverse reaction. Nanoparticles (NPs) constructed of anatase microspheres, one form of titanium dioxide (TiO2), with a high specific surface area are fabricated in this study in a facile one-step process using homogeneous precipitation at 90 °C under atmospheric pressure using titanium sulfate (Ti[SO4]2) and urea as the titanium source and precipitant, respectively. The molar ratio of silver (Ag) to TiO2 can be changed by varying the amount of silver nitrate (AgNO3). The high specific surface area of the TiO2 microspheres combined with Ag particles (Ag/TiO2) exhibit excellent antibacterial properties against both Staphylococcus aureus and Escherichia coli. In addition, the Ag/TiO2 material in this work possesses satisfactory biological performance on MC3T3-E1 cells. The high specific surface area of Ag/TiO2 together with good antibacterial properties and cytocompatibility provide promising applications in dentistry, orthopedics, and other fields of medicine that use biomedical devices.

Tuning chemoselectivity in O-/N-arylation of 3-aryl-1,2,4-oxadiazolones with ortho-(trimethylsilyl)phenyl triflates via aryne insertion.

Herein, we first describe finely tunable chemoselectivity in arylation of 3-aryl-1,2,4-oxadiazolones with ortho-(trimethylsilyl)phenyl triflates, including O-arylation enabled by catalytic amount of silver nitrate and metal-free N-arylation. Both the arylation reactions can tolerate a series of functional groups, and afford the corresponding products in moderate to good yields.

Facile and eco-friendly fabrication of AgNPs coated silk for antibacterial and antioxidant textiles using honeysuckle extract

Recently, there is a growing trend towards the functionalization of silk through nanotechnology for the prevention of fiber damage from microbial attack and the enhancement of hygienic aspects. Considering sustainable development and environmental protection, the eco-friendly fabrication of silver nanoparticles (AgNPs)-modified silk using natural extracts has currently become a hot research area. This study presents a facile strategy for the fabrication of colorful and multifunctional silk fabric using biogenic AgNPs prepared by honeysuckle extract as natural reductant and stabilizing agents. The influences of pH and reactant concentrations on the AgNPs synthesis were investigated. The color characteristics and functionalities of AgNPs treated silk were evaluated. The results revealed that the particle size of AgNPs decreased with increasing pH. The diameter of AgNPs decreased with increasing amount of honeysuckle extract and reducing amount of silver nitrate. The transmission electron microscopy image showed that the AgNPs were spherical in shape with a narrow size distribution. The treated silk showed excellent antibacterial activities against E. coli and S. aureus, and certain antioxidant activity. Both of the antibacterial and antioxidant activities were well maintained even after 30 washing cycles. This work provides a sustainable and eco-friendly approach to the fabrication of AgNPs coated silk for colorful and long-term multifunctional textiles using honeysuckle extract.

Seedless synthesis of gold nanorods with longitudinal surface plasmon resonance wavelength of 1200 nm

ABSTRACTGold nanorods with the longitudinal plasmonic resonance peak position up to 1200 nm are prepared using an improved seedless synthetic technique. In this method, dopamine is employed as the weak reducer, whereas cetyltrimethylammonium bromide and sodium oleate are used as the binary surfactant mixture. Gold nanorods produced at various amounts of silver nitrate and hydrochloric acid were characterized by visible-near-infrared spectroscopy and scanning electron microscopy. Results show that the sizes, length-to-width aspect ratios, and the corresponding longitudinal surface plasmon resonance peaks of the synthesized gold nanorods can be tuned by altering the silver nitrate and hydrochloric acid amounts. The present method provides a new procedure for fabrication of gold nanorods with a broad range of plasmonic resonance peaks, which has a great potential for applications such as photothermal therapy and sensing.

Growth process and anticancer properties of gold nanorods.

Gold nanoparticles have been of great interest because of their unique optical properties, facile synthesis and conjugation. Among various shapes of gold nanoparticles, gold nanorods have been widely studied. They can be conjugated with different molecules for biomedical applications, such as tumor imaging and therapy. However, few researchers have studied the antitumor properties of bare gold nanorods. In this study, unfunctionalized gold nanorods were synthesized and tested on breast tumor cells. Results showed that the aspect ratio of gold nanorods could be easily influenced by both reaction time and the amount of silver nitrate in the growth solution. A new growth process is proposed here based on the UV-Vis spectra and TEM images of gold nanorods at different reaction times. More importantly, cell studies showed that within a certain concentration range, the gold nanorods can selectively kill tumor cells while having limited or little influence on healthy mammalian (dermal fibroblast) cells. Thus, this study shows promise for the use of bare gold nanorods for further study alone or in combination with photothermal treatment. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2616-2621, 2017.

An Efficient and Benign Antimicrobial Depot Based on Silver-Infused MoS2.

Silver nanoparticles (AgNPs) have been used as a broad-spectrum antimicrobial agent, whose toxicity originates from the localized release of Ag+ ions. However, the residual AgNPs core could generate potential risk to humans and waste of noble metals. Herein, we infused the cysteine-modified molybdenum disulfide with minimum Ag+ ions and coated with a layer of cationic polyelectrolyte to construct an efficient and benign antimicrobial depot. The system exhibited much enhanced broad-spectrum antibacterial activity compared with an equivalent amount of silver nitrate, owing to its increasing accessibility of released Ag+ to the cell walls of microorganisms. More importantly, the antibacterial system could be successfully applied to treat wound infection, while retaining high antibacterial activities, exhibiting negligible biotoxicity and avoiding the waste of Ag.

Understanding the Seed-Mediated Growth of Gold Nanorods through a Fractional Factorial Design of Experiments.

Since the development of simple, aqueous protocols for the synthesis of anisotropic metal nanoparticles, research into many promising, valuable applications of gold nanorods has grown considerably, but a number of challenges remain, including gold-particle yield, robustness to minor impurities, and precise control of gold nanorod surface chemistry. Herein we present the results of a composite fractional factorial series of experiments designed to screen seven additional potential avenues of control and to understand the seed-mediated silver-assisted synthesis of gold nanorods. These synthesis variables are the amount of sodium borohydride used and the rate of stirring when producing seed nanoparticles, the age of and the amount of seeds added, the reaction temperature, the amounts of silver nitrate and ascorbic acid added, and the age of the reduced growth solution before seed nanoparticles are added to initiate rod formation. This statistical experimental design and analysis method, besides determining which experimental variables are important and which are not when synthesizing gold nanorods (and quantifying their effects), gives further insight into the mechanism of growth by measuring the degree to which variables interact with each other by mapping out their mechanistic connections. This work demonstrates that when forming gold nanorods by the reduction of auric ions by ascorbic acid onto seed nanoparticles, ascorbic acid determines how much gold is reduced, and the amount of seeds determine how it is divided, yet both influence the intrinsic growth rates, in both width and length, of the forming nanorods. Furthermore, this work shows that the reduction of gold proceeds via direct reduction on the surface of seeds and not through a disproportionation reaction. Further control over the length of gold nanorods can be achieved by tuning the amount of silver nitrate or the reaction temperature. This work shows that silver does not directly influence rod length or width, and a new primary role for silver is proposed as a catalyst promoting the reduction of gold on the ends of forming nanorods. Furthermore, this silver catalyst is removed from the reaction by adsorption onto the surface of the growing nanorod. This work also demonstrates the importance of freshly prepared silver nitrate and ascorbic acid solutions, free from even a few hours of photodegradation, in preparing gold nanorods with high shape purity and gold yield.

Mechanochemical Synthesis and Characterization of Silver (Ag<SUP>+</SUP>) and Tantalum (Ta<SUP>5</SUP><SUP>+</SUP>) Doped Calcium Silicate Nanopowders

Calcium silicate (CS) nanopowders doped with monovalent (Ag + ) and pentavalent (Ta 5+ ) cations were successfully synthesized via a mechanochemical method. This technique consisted of milling mixtures of calcium oxide, silicon dioxide and variable amounts of silver nitrate as a source of Ag + or tantalum pentoxide as source of Ta 5+ , respectively, using a high-energy planetary ball mill for 3 h. To investigate the influence of subsequent annealing on the phase evolution, the mechanosynthesized powders were annealed at 1000 � C for 2 h. The results from the structural investigation confirmed that the synthesized doped and undoped powders crystallized in both � -CS (Parawollastonite, monoclinic crystal system) and � -CS (Cyclowollastonite, anorthic crystal system). With increasing the degree of Ag substitution, no obvious phase changes were observed in the synthesized powders; however, the presence of 5 wt% of Ta source led to a significant volume of phase changes. The results of EDX analysis showed that the stoichiometric doped and undoped CS powders were in good agreement with the literature data for crystalline CS. From TEM observations, the doped nanopowders annealed at 1000 � C for 2 h entailed polycrystalline nanoparticles with an average length of around 1 � m and mean width of about 200 nm.

Design of Stable Plasmonic Dimers in Solution: Importance of Nanorods Aging and Acidic Medium

We describe a simple and effective strategy to couple gold nanorods (GNRs) into end to end dimers and freeze the assembly in water. The assembly is initiated using cysteine and driven by hydrogen bonding between two cysteine. We show that the aging of GNRs samples impacts both the assembly kinetics and the final yield of GNRs dimers. The addition of an appropriate amount of silver nitrate induces the immediate termination of GNRs dimerization and stabilizes the small aggregates in solution for at least 24 h.

Argentation high performance liquid chromatography on-line coupled to gas chromatography for the analysis of monounsaturated polyolefin oligomers in packaging materials and foods

Multidimensional chromatography based on two-dimensional high performance liquid chromatography on-line coupled to gas chromatography (on-line HPLC–HPLC–GC) enables the separate analysis of saturated, monounsaturated and aromatic hydrocarbons in packaging materials like polyolefins or paperboard and their migrates into foods. Since normal-phase HPLC on silica gel did not preseparate saturated from monounsaturated hydrocarbons, a separation step on a normal-phase HPLC column treated in the laboratory with an optimized amount of silver nitrate was added. The preparation of this HPLC column and the instrumental set-up are described, followed by examples showing the potential of the method. In a preliminary investigation of 11 polyolefin granulates for food contact up to 40% monounsaturated hydrocarbons among the oligomers C16–35 were determined.

Nanocomposite Nanofibers of Polyacrylonitrile (PAN) and Silver Nanoparticles (AgNPs) Electrospun from Dimethylsulfoxide

In this study, DMSO was used as the solvent and composite nanofibers of PAN with 1 and 3w% AgNO 3 content were electrospun. Then silver nanoparticles were in situ synthesized by chemical reduction. The effect of silver nitrate amount on the morphology, conductivity and mechanical properties of PAN/AgNPs composite nanofibers were investigated. Beadless and uniform composite nanofibers, the diameters of which were in the 499-515 nm range, were successfully electrospun. The breaking stress and breaking elongation of PAN/Ag composite nanofibers were higher than the neat PAN nanofibers. The conductivity was improved to around 10 -8 S/cm with the incorporation silver nanoparticles.

Silver dopants for targeted and untargeted direct analysis of unsaturated lipids via infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI).

Unsaturated lipids play a crucial role in cellular processes as signaling factors, membrane building blocks or energy storage molecules. However, adequate mass spectrometry imaging of this diverse group of molecules remains challenging. In this study we implemented silver cationization for direct analysis by infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) to enhance the ion abundances for olefinic lipids and facilitate peak assignment. Trace amounts of silver nitrate were doped into the electrospray solvent of an IR-MALDESI imaging source coupled to an Orbitrap mass analyzer. Calcifediol was examined as a model compound to demonstrate the effect of silver dopants on sensitivity and assay robustness. Dried human serum spots were subsequently analyzed to compare Ag-doped solvents with previously described solvent compositions. Mass differences as well as ion abundance ratio filters were employed to interpret results based on the characteristic isotopic pattern of silver. Olefinic lipids were readily observed as silver adducts in IR-MALDESI analyses. Silver cationization decreased the limit of detection for calcifediol by at least one order of magnitude and was not affected in complex biological matrices. The ion abundance ratio and mass difference of [M + (107) Ag(+)](+) and [M + (109) Ag(+)](+) were successfully applied to facilitate the spectral assignment of silver adducts. Overall, silver cationization increased the analyte coverage in human serum by 43% compared with a standard IR-MALDESI approach. Silver cationization has been shown to enhance IR-MALDESI sensitivity and selectivity for unsaturated lipids, even when applied to complex samples. Increased compound coverage, enhanced robustness as well as the developed tools for peak assignment and mapping of isotopic patterns will clearly benefit future mass spectrometry imaging studies.

The effects of silver nitrate on the structure and properties of polyurethanes containing pyridyl units

In this study, 2,6-pyridinedimethanol was used as a chain extender to synthesize a new polyurethane, PDM-PU. Further, various amounts of silver nitrate were incorporated to produce PDM-PU/AgNO3 complexes. FT-IR and UV–Vis analyses confirm the formation of complex in the PDM-PU/AgNO3. DSC and DMA results show that the glass transition temperature (T g), dynamic T g and storage modulus at 25 °C of the PDM-PU/AgNO3 complexes increase with increasing AgNO3 content. This is due to the formation of complex structure that can restrict the segmental motion of polymer chains. The TGA and stress–strain test results show that the thermal decomposition temperature, tensile strength and elongation at break increase with the AgNO3 content initially. Then, they decrease inversely. This indicates that the formation of complex structure raises these properties when the AgNO3 content is below certain value. But as more coordinate bonds were formed, the specimens become brittle. In addition, the crosslink effect caused by coordinate bonds inhibits the dissolution of polymer chains and thereby reduces the swelling degree of the complexes in solvent. Furthermore, AgNO3 imparts antibacterial activity against S. aureus and K. pneumoniae to the complexes