Colloidal Solution Of Silver Nanoparticles Research Articles

Synthesis of Silver Nanoparticles and Silver-Gold Binary System by Galvanic Replacement in an Ultrasonic Field

The conditions for the synthesis of colloidal solutions of silver nanoparticles by galvanic replacement in an ultrasonic field and the AgAuNP binary system by galvanic replacement have been studied. It has been shown that colloidal solutions of stabilized nanoparticles with absorption maxima at 410 nm (AgNPs) and 540...560 nm (AgAuNPs) are formed in solutions of sodium polyacrylate and metal precursors of AgNO3 and H[AuCl4]. The synthesized AgAuNPs are spherical in shape and their size does not exceed 20 nm.

Phytochemical Investigation and Characterization of Azadirachta Indica-Mediated Silver Nanoparticles and Their Potential as Antibacterial and Antidiabetic Agents

In this study, we report the synthesis of silver nanoparticles (AgNP’s) by reducing silver ions from a solution of silver nitrate with an aqueous extract from Azadirachta indica. Using silver ions as the catalyst, nanoparticles were formed in 8[Formula: see text]min without the use of toxic chemicals. As evidenced by UV-vis spectroscopy, a broad surface plasmon resonance spectrum at 225[Formula: see text]nm was detected, which indicates the colloidal solution of silver nanoparticles is stable and produces silver nanoparticles. As revealed by the fourier transform-infrared spectrometer (FTIR) analysis, the flower extract contained a variety of biomolecules that acted as capping and reducing agents for the synthesis of AgNPs. As determined by X-ray diffraction (XRD), silver nanoparticles displayed a crystalline structure and ranged in size from 18 to 39[Formula: see text]nm. In addition to these findings, transmission electron microscopy (TEM) images showed that the silver nanoparticles were spherical and rod-shaped, as confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDAX). A variety of pathogenic bacteria, such as Klebsiella pneumoniae, Escherichia coli, Bacillus subtilis and Staphylococcus aureus, were tested against AgNP’s antibacterial properties. A significant inhibition zone was observed for Escherichia coli when AgNPs were applied at different concentrations. Silver nanoparticles were shown to have antidiabetic effects through a diphtheria assay with inhibition rates ranging from 31.09% to 83.33% for concentrations of 50–250[Formula: see text][Formula: see text]g/mL. As researchers seek natural sources of compounds with potential health benefits, silver nanoparticles were also investigated for their antioxidant properties.

Synthesis and Antibacterial Activity of Ultrasmall Silver Nanoparticles by Pulsed Laser Ablation in Deionized Water

Background: The main objective of this work is the synthesis and evaluation of silver nanoparticles (Ag NPs) by using pulsed laser ablation of a silver (Ag) target in deionized water and examining their antibacterial activity. Methods: Colloidal solutions of silver nanoparticles were prepared with different pulsed laser energies (620, 880, and 1000) mJ of wavelength 1064 nm and frequency 10 Hz. To determine their structure, optical, morphology, elemental composition, and infrared spectra, the synthesized Ag NPs were characterized using various high-throughput analytical techniques such as (UVVis) spectroscopy, transmission electron microgram (TEM), electron dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectra, and Zeta potential. Results: The results show that the properties of synthesized Ag NPs depend much more on the laser energy. The laser energy can be used to control the properties of the prepared nanoparticles. Uniform distributions of spherical ultrasmall Ag NPs with an average size of (3) nm were obtained suspended in deionized water, which is the most effective size for antibacterial activity. However, the result indicated that the ablated Ag NPs were stable for 4 months in deionized water. The antibacterial activity of the colloidal solution of synthesized Ag NPs against Gramnegative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria was then examined using the agar-well diffusion method. Conclusion: It was found that the prepared nanoparticles exhibited strong activity against E. coli and S. aureus bacteria growth. The average zones of inhibition of Ag NPs were found to be about (26) mm for E. coli and (32) mm for S. aureus bacteria.

Evaluation of the Microbiological Effect of Colloidal Nanosilver Solution for Root Canal Treatment.

Background: The goal of endodontic treatment, along with the preparation of the root canal and giving it a shape corresponding to the obturation technique, is the drug treatment of the canal. The aim of this study was to determine the antibacterial effect of a colloidal solution of nanosilver at its various dilutions on root canal microorganism. Materials and methods: A solution of silver nanoparticles at a concentration of 10,000 ppm (1.0%) was diluted in various concentrations (10 solutions from 1% to 0.0025%). Cultures used for research: Str. agalacticae ATCC 3984, E. faecalis ATCC 323, St. aureus ATCC 4785, C. albicans ATCC 10231. After thawing, cultures of microorganisms were introduced into a liquid nutrient medium: cerebral heart broth for bacterial cultures and Sabouraud broth for C. albicans. The cultivation was carried out at a temperature of 37 °C for 24 h. A bacterial suspension for inoculation was prepared from a microbial sediment according to a turbidity standard of 0.5 McFarland in saline. Then, 100 μL of the obtained suspension of microorganisms was inoculated by the “lawn” method using a spatula on the Muller–Hinton medium. Solutions of silver nanoparticles were introduced into wells prepared in agar with a sterile metal punch. Further incubation was carried out for 24 h at 37 °C. Results: colloidal solution of silver nanoparticles at concentrations of 1%, 0.75%, 0.5% inhibited the growth of Str. agalacticae ATCC 3984 with a growth retardation zone of 6–7 mm. The E. faecalis ATCC 29212 strain was sensitive to solutions of silver nanoparticles at concentrations of 1%, 0.75%, 0.5% with a growth inhibition zone of 6–7 mm. Strain St. aureus 4785 demonstrated sensitivity to solutions of silver nanoparticles at concentrations of 1%, 0.75%, 0.5%, 0.1%, 0.05% with a growth retardation zone of 6-8 mm. Conclusion: colloidal solutions of silver nanoparticles have antimicrobial action against gram-positive bacteria (Str.agalacticae ATCC 3984, St. aureus ATCC 4785, E. faecalis ATCC 29212) and yeast-like fungi of the genus Candida (C. albicans ATCC 10231, C. albicans 672 and C. albicans D-225M), but this action is strain-specific and depends on the concentration of the solution.

Vancomycin as an Antibacterial Agent Capped with Silver Nanoparticles: An Experimental Potential Analysis.

For the treatment of various infections, a variety of antimicrobial drugs are formulated. Nevertheless, many bacterial infections now exhibit antibiotic resistance due to the widespread utilization antibiotics. Methicillin-resistant among the most dangerous multidrug-resistant bacteria is Staphylococcus aureus (MRSA). Vancomycin became a viable therapy option due to MRSA resistance to methicillin medicines. One of the well-informed antibacterial compounds with wideband antibacterial activity is silver nanoparticles (AgNPs). AgNPs are thus suitable candidates for usage in conjunction alongside vancomycin to increase its antibacterial effect. The goal of the present research work is to boost the antibacterial potency of the glycopeptide antibiotic vancomycin towards Gram-positive (Staphylococcus aureus) but also Gram-negative (Escherichia coli) bacteria. The chemical reduction approach is used to create a colloidal solution of silver nanoparticles utilizing silver nitrate as a precursor in the environment of the ionic surfactant trisodium citrate that serves as covering including reducing reagent. Vancomycin was used to functionalize the synthesized nanoparticles and create the nanodrug complex (Van@AgNPs). The synergistic antibacterial potential of silver nanoparticles coated with vancomycin on both test pathogens was investigated using the agar well diffusion technique. The antibacterial potency for both classes of bacteria has significantly increased, according to the well diffusion test. It has been noted that this improvement is synergistic instead of additive.

In Vitro Activation of Ampicillin Effect with Plant Extract Cocktail-Mediated Silver Nanoparticles Against Multidrug-Resistant Bacteria Pathogens

Background: The emergence of antibiotic resistance and the continuing evolution of resistance even to newer drugs have always been a global challenge. In the pursuit of innovative solutions, there is growing interest in using nanomaterials with antibacterial potentials to combat this menace. Objectives: In this study, plant extract cocktail-mediated silver nanoparticles (PAgNPs) was used to stimulate the antibacterial effect of ampicillin (AMP) against multidrug-resistant (MDR) bacterial pathogens. Methods: The agar well diffusion technique was used to investigate the potentials of PAgNPs in activating the antibacterial activity of AMP in MDR bacteria, including Escherichia coli, Klebsiella pnuemoniae, Micrococcus luteus, and Clostridium difficile. Plant extract cocktail-mediated silver nanoparticles were synthesized by reacting 9 mL of 1 mM of silver nitrate with 0.5 mL each of Citrus limon juice and aqueous Newbouldia laevis extract under bright sunlight for 10 minutes. Plant extract cocktail-mediated silver nanoparticles were characterized using UV-visible spectroscopy (UV-Vis) and higher resolution transmission electron microscopy (HRTEM) with energy dispersive x-ray spectroscopy (EDS). Results: Plant extract cocktail-mediated silver nanoparticles colloidal solution was reddish-brown with a 441-nm surface plasmon resonance (SPR) absorption peak. The HRTEM micrograph showed the varied shaped silver nanoparticles (AgNPs) with the average size of 23.49 ± 10.49 nm. Similarly, EDS showed a strong typical metallic silver nanocrystallites absorption peak at 3.0 keV. The PAgNPs activate the AMP activity in MDR E. coli, M. luteus, K. pnuemoniae, and C. difficile. Conclusions: The present findings suggest that PAgNPs can be considered a suitable candidate for developing novel antibacterial drugs to combat the growing threat of antibiotic resistance.

In vitro antimicrobial activity evaluation of AgNPs and lemon peel extracts

Quality assurance in fresh food, as well as biosafety for human consumption has led us to develop technological alternatives that guarantee food safety in the face of the SARS-CoV-2 pandemic. An alternative is nanomaterials, which have multiple properties or mechanisms of action, such as antimicrobials, antifungals and / or antivirals, making them an alternative as a biocidal agent of great interest in the current pandemic that humanity is experiencing. nowadays. In this work, a preliminary study is presented on the in vitro antimicrobial action mechanism of aqueous extracts of lemon peel mixed with a colloidal solution of silver nanoparticles (AgNPs) biosynthesized from plant extracts, and with a range of diameters between 20 and 50 nm. The microbiological tests in Escherichia coli (ATCC 25922) demonstrated a growth inhibitory effect for all treatments with AgNPs, while for the extracts a reduced inhibitory effect was observed in disk diffusion and null for the test in nutritive broth. As a result of preliminary studies in lemons, we conclude that the use of nanotechnology in colloidal solution for the agricultural area promotes food safety and its application can be extended to other agricultural products susceptible to contamination.

Comparative Analysis of the Use for Prophylactic Purposes of an Antibiotic and Colloidal Solution of Silver Nanoparticles to Broiler Chickens

Comparative Analysis of the Use for Prophylactic Purposes of an Antibiotic and Colloidal Solution of Silver Nanoparticles to Broiler Chickens

Generation of silver nanoparticles from thin films and their antibacterial properties

Colloidal solutions of silver nanoparticles (NPs) were obtained by ultrashort-pulse laser ablation of silver films of variable thickness in water at different fluences, pulse durations and laser exposures. Characterization of these particles was performed by scanning electron microscopy, optical transmission spectroscopy, and dynamic light scattering. A monotonic increase in the extinction coefficient and in the average diameter of the colloidal particles—from 20 to 180 nm—was observed as a function of laser fluence and exposure. Antibacterial properties of colloidal silver NPs were investigated by the microbiological ‘Live/Dead Biofilm Viability Kit’ method.

Plasmonic features of free-standing chitosan nanocomposite film with silver and graphene oxide for SERS applications

A scalable procedure of SERS substrates design was developed using a novel plasmonic structure based on a freestanding chitosan film, silver nanoparticles, and graphene oxide. Chitosan provides a uniform distribution of silver nanoparticles from a colloidal suspension and, therefore, a reproducible Raman signal from local areas of measurements of several tens of microns. The addition of graphene oxide (GO) to the colloidal solution of silver nanoparticles suppresses the tortuous background fluorescence signal from the analyte and leads to an increase in the signal-to-fluorescence background intensity ratio by up to 6 times as compared to structures without GO. The manufactured plasmonic polymer nanocomposite provides a detection limit of down to 100 pM for R6G using a laser wavelength of 532 nm through a portable ×10 objective. The high colloidal stability of GO in water and the use of an aqueous colloid of silver nanoparticles simplify the procedure for creating a substrate by applying the GO-silver composite on the surface of a chitosan film without a need to form a GO film. Therefore, our approach paves a promising avenue to provide more sensitive detection even for the fluorescent analytes with short-wavelength lasers (532, 633 nm) instead of IR (785, 1024 nm) and foster the practical application of the developed plasmonic composites on portable Raman spectrometers.

Assessment of the effect of a colloidal solution of silver nanoparticles on the sowing quality of seeds

The article presents the results of laboratory studies to assess the effect of a colloidal solution of silver nanoparticles on the sowing quality of wheat seeds of the Novosibirskaya 15 strain recommended for cultivation in the Krasnoyarsk Territory and an assessment of its influence on its seed productivity. It was found that the use of a colloidal solution of silver nanoparticles in the processing of seed material of the Novosibirskaya 15 soft spring wheat strain significantly increases the rate of seed growth, raising it from 63% in the control to 87% in the variant with a 50% solution of silver nanoparticles. It was found that the colloidal solution of silver nanoparticles did not affect on the indicators of seed germination and their germination energy.

Functionalizing cotton fabrics through herbally synthesized nanosilver

The ultraviolet (UV) radiation is increasing in atmosphere due to the continuous increasing of global warming throughout the globe, which causes a negative impact on the human skin. The aim of this work is to produce an ecofriendly fabric having functional properties of UV protection & antimicrobial using herbal synthesized colloidal solution of silver nanoparticles (H-AgNPs). This solution was synthesized with Tulsi ( Ocimum tenuiflorum) extract as a reducing and capping agent. The cotton woven sample was developed with ten layers of colloidal solution of H-AgNPs using anionic surfactant sodium dodecyl sulfate (SDS) through pad-dry-cure method. Besides, another sample developed with the mixture of natural oils and the same concentration of H-AgNPs colloidal solution. Treated samples were subjected to color strength (K/S value) measurement, color fastness test, scanning electron microscopy (SEM) analysis, ultra-violet protection factor (UPF) test and antimicrobial test for evaluating their different functional & aesthetic performances. Testing data reveals that the treated sample has higher color strength of 0.95 compared to the untreated 0.04 and excellent all-round color fastness ratings of 4–5 for wash, 6–7 for light, 4 for dry rubbing & 3–4 for wet rubbing in contrast to the untreated one. SEM analysis confirmed that the H-AgNPs successfully deposited on cotton fibre surface. X-ray diffraction (XRD) experiment revealed the mean crystal size of H-AgNPs about 23 ± 3 nm. On the other hand, tensile strength increased by 6N & elongation 3–4% in both warp and weft direction. Moreover, less UV transmission of 1.04% & 3.12% for UV-B and UV-A respectively represents outstanding UV protection. In addition, antimicrobial test depicts the zone of inhibition for gram-positive S.aureus 9.5± 0.5 mm & gram-negative E.coli 10.5± 0.9 mm, respectively. The presence of phytochemicals of Tulsi extract, natural oils, and chemical compounds of cellulosic cotton has been further analyzed by Fourier transform infrared spectroscopy (FTIR) spectrum investigation.

Development of UV Protective Finished Fabric using Herbal Synthesized Colloidal Solution of Silver Nanoparticles

Development of UV Protective Finished Fabric using Herbal Synthesized Colloidal Solution of Silver Nanoparticles

Structural Characteristics and Ionic Composition of a Colloidal Solution of Silver Nanoparticles Obtained by Electrical-Spark Discharge in Water

Structural Characteristics and Ionic Composition of a Colloidal Solution of Silver Nanoparticles Obtained by Electrical-Spark Discharge in Water

Genomic Damage Induced in Nicotiana tabacum L. Plants by Colloidal Solution with Silver and Gold Nanoparticles.

Tobacco seedlings (Nicotiana tabacum L cv. Wisconsin 38) were treated for 24 h with colloidal solution of silver and gold nanoparticles (AgNPs and AuNPs) of different size or cultivated for 8 weeks on soil polluted with these NPs. DNA damage in leaf and roots nuclei was evaluated by the comet assay. AgNPs of the size 22–25 nm at concentrations higher than 50 mg·L−1 significantly increased the tail moments (TM) values in leaf nuclei compared to the negative control. Ag nanoparticles of smaller size 12–15 nm caused a slight increase in tail moment without significant difference from the negative control. The opposite effect of AgNPs was observed on roots. The increasing tail moment was registered for smaller NPs. Similar results were observed for AuNPs at a concentration of 100 mg·L−1. DNA damaging effects after growing tobacco plants for 8 weeks in soil polluted with AgNPs and AuNPs of different size and concentrations were observed. While lower concentrations of both types of particles had no effect on the integrity of DNA, concentration of 30 mg·kg−1 of AgNPs caused significant DNA damage in leaves of tobacco plants. AuNPs had no effect even at the highest concentration. The content of Ag was determined by ICP–MS in above-ground part of plants (leaves) after 8 weeks of growth in soil with 30 mg·kg−1. AgNPs and was 2.720 ± 0.408 µg·g−1. Long term effect is much less harmful probably due to the plant restoration capability.

Application of gold and silver nanoparticles for selective assay of spermine in mixture with spermidine.

To assess the applicability of the novel technique based on the detection of spermine in solutions by spectrocolorimetric method using gold and silver colloidal nanoparticles. Colloidal solution of gold nanoparticles were synthesized by chemical reduction of tetrachlorauric acid with trisodium citrate. Colloidal solution of silver nanoparticles was obtained by chemical reduction of silver nitrate with tryptophan. The absorption spectra of gold/silver metal colloids and their mixtures with polyamines were recorded. The increase of spermine concentration in solution caused the change in the intensity of the band of localized surface plasmon resonance that was not affected by the excess of spermidine. The color shift in colloidal gold due to its aggregation with spermine was registered spectrophotometrically. The principal possibility of selective quantification of spermine in the presence of spermidine in extremely high concentration using colloidal gold has been shown. This method can be used to assay selectively spermine in biological fluids.

Spectroscopic characteristics of colloidal solutions of metal nanoparticles

Nanoparticles are finding more and more practical applications in various fields of human activity, including veterinary and medicine. Due to the fact that the effectiveness of activity of colloidal solutions of nanoparticles is directly related to the state of aggregation of nanosized particles, it is urgent to use fast and convenient methods for assessing the physicochemical characteristics of such preparations. Nanoparticles have unique optical properties that depend on their size and shape. They can be determined by the refractive index of the light on the surface of the nanoparticles in a phenomenon known as plasmon resonance, which makes UV-Vis spectroscopy a valuable tool for studying and evaluating the characteristics of nanomaterials. Goal of the study is to study the optical characteristics of several samples of colloids of nanoparticles of noble metals (silver) and bioelements (copper, silicon dioxide) in order to determine the possibility of further application of UV-Vis spectroscopy for evaluation of activity and stability of colloidal solutions of nanoparticles. Commercial preparations based on nanoparticles of noble metals (silver) or bioelements (copper, silicon dioxide) in working dilutions recommended by manufacturers were used to study optical characteristics of the colloidal solutions. Optical density and absorption spectra were determined at the wavelengths (nm): 300-800 nm. The f plasmon surface resonance has been found in all test preparations, while all of them exhibited obvious nonlinear optical properties. The most pronounced plasma resonance peak is found in the colloidal solution of silver nanoparticles within a wavelength of 420 nm. In the case of a colloidal solution of copper nanoparticles, the peak of plasmon resonance was less pronounced and had a red shift (peak at 560 nm). In the colloidal solution of silicon silica, the plasmon resonance was less pronounced than other test preparations, being shifted to the blue side of the spectrum (360 nm).

Antimicrobial, Antioxidant, and Dye Degradation Properties of Biosynthesized Silver Nanoparticles From Artemisia Annua L.

The biosynthesis of metallic nanoparticles with plant extract is a promising alternative method to traditional chemical methods. Artemisia annua L is a well-known Chinese herb for its potent therapeutic anti-malarial activity and antitumor effects. Artemisinin, a sesquiterpene lactone derived from Artemisia annua L. Although artemisinin's anticancer effect has been extensively reported, the precise mechanisms underlying its cytotoxicity remain under intensive study. In the present work rapid and simple method for green synthesis of silver nanoparticles with the leaf extract of the therapeutic plant Artemisia annua L.was carried-out. The biologically synthesized silver nanoparticles were analyzed using spectroscopic methods like UV–visible spectroscopy. Fourier transforms infrared spectroscopy (FT-IR), Zeta potential, and particle size. The green Aa-AgNPs are characterized by spectral analysis by Nanodrop-UV-visible spectroscopy. The surface Plasmon resonance peak of silver nanoparticles in colloidal solution showed maximum absorption 441nm. FT-IR spectroscopy results indicate the O-H phenolic group's participation, C=C aromatic stretching, N-H secondary amide stretching, and C-H methylene group stretching. Dynamic light scattering measurements of Aa-AgNPs revealed that the particle size is between 5-20 nm. The zeta potential of the green synthesized Aa-AgNPs was found to be -26.1 mV. The high negative potential indicates long-term stability. The antioxidant activity of Aa-AgNPs was evaluated by DPPH assay. The results revealed that they have very good antioxidant activity, which can be useful as a potential free radical scavenger. The biosynthesized Aa-AgNPs of Artemisia annua exhibited good antimicrobial activity. The Aa-AgNPs showed excellent catalytic activity in the reduction of lemon yellow and orange-red food dyes. The Aa-AgNPs can also act as an effective seed germination agent. Hence it is concluded that the green Aa-AgNPs can be useful for various biomedical and industrial applications.

SYNTHESIS SILVER NANOPARTICLES AND ITS APPLICATION FOR WASTEWATER TREATMENT: CATALYTIC AND PHOTOCATALYTIC DEGRADATION METHYLENE BLUE

This paper aims to propose a simple, eco-friendly method for obtaining colloidal solutions of silver nanoparticles (Ag NPs) by using of contact non-equilibrium low-temperature plasma in presents carboxymethyl cellulose (CMC) as a stabilizing agent and investigation on the decolorization of representative cationic phenothiazine dye in presence of nanocatalysts. Silver nanoparticles were prepared in aqueous AgNO3 solution by using of contact non-equilibrium low-temperature plasma in the present of carboxymethyl cellulose as capping agent. Ultraviolet–visible (UV) spectroscopy, X-ray diffraction, zeta potential, DLS analysis and SEM were used to study the formation and properties of silver nanoparticles. Measurements of optical spectra showed that the surface plasmon resonance was localized around 410-418 nm when the reaction mixture exposed to plasma for 1-5 min. The nanoparticles exhibited a good catalytic reduction for methylene blue dye in the presence of NaBH4. It followed pseudo-first order kinetics with a rate constant of 0.16 min−1. The catalytic degradation reaction was completed (98-99%) within 25 min. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Synthesized silver nanoparticles were effectively degrading the dye nearly 98% at 70-72 h of exposure time.

Silver Nanoparticles Stabilized with Chitosan Succinamide: Synthesis and Antibacterial Activity

A water-soluble chitosan derivative, chitosan succinamide, was used as a polymer matrix for the formation of silver nanoparticles via ion reduction under microwave irradiation in the presence of a D-glucose reducing agent. UV spectroscopy confirmed the presence of silver nanoparticles in the synthesized colloidal solution. Transmission electron microscopy showed that the synthesized silver nanoparticles had a spherical shape. The obtained diffractograms confirm the presence of reflexes characteristic of the crystal lattice of metallic silver. In vitro studies showed that the synthesized colloidal solution of silver nanoparticles exhibits pronounced antibacterial activity against strains of the gram-positive bacteria Bacillus subtilis ATCC 6633 and Bacillus coagulans 429.