Size Of AgNPs Research Articles

An approach to estimate the contribution of signal noise to the diameter uncertainty of individual silver nanoparticles and resolution of spICP-MS analysis

The factors influencing the signal noise and its contribution to the uncertainty of a single AgNP size in spICP-MS were investigated.

A Review on Plant Mediated Synthesis of Silver Nanoparticles as a Greener Approach

Metal nanoparticles are used in all phases of science, including medical fields. They still seduce scientists to explore new dimensions for their respective value, which is usually attributed to their corresponding small sizes. Among the other metallic nanoparticles, silver nanoparticles (AgNPs) aroused a keen interest. The chemical methods used to synthesize AgNPs involve reducing and stabilizing agents, which subsequently become risks to the environment. For these reasons, the green synthesis of AgNPs is a significant area of interest. Among the variety of biological molecules used to synthesize AgNPs, the biological molecules obtained in the form of plant extracts are superior to others because of the ease of handling and the reduction of costs. Many plant parts have been used to synthesize AgNPs such as whole plants, leaves, seeds, bark etc. The synthesis of AgNPs by plant extracts is due to the presence of a large amount of organic chemicals such as carbohydrates, fats, proteins, enzymes and coenzymes, phenolic flavonoids, terpenoids, alkaloids, gum, etc., capable of donating an electron to reduce Ag+ ions to Ag0. The active ingredient responsible for the reduction of Ag+ ions varies depending on the extract used. The size and size distribution of AgNPs synthesized with plant extracts depend on plant extract concentration, silver nitrate concentration, pH of the medium, incubation time and temperature. These factors can be modified to refine the properties of AgNPs. Almost all of these conditions have an optimal value to obtain smaller size AgNPs with a narrow size distribution.

Green Fabrication of Bioactive Silver Nanoparticles Using Mentha pulegium Extract under Alkaline: An Enhanced Anticancer Activity.

Fabrication of silver nanoparticles (AgNPs) using Chinese herbal medicine is popular as the bioactive components included in them would generate potential synergistic effect with the metal nanoparticles. The leaf of Mentha pulegium, whose extract contains a range of phytochemicals and exhibits a wide spectrum of bioactivities, is used as Chinese herbal medicine after drying naturally. Thus, the green synthesis of AgNPs using Mentha pulegium has aroused interests from analysts. However, the biosynthesis of AgNPs under alkaline conditions and the biological activities remain elusive, where alkaline conditions may influence the physicochemical properties and the biological activities of biosynthesized AgNPs. In this study, we were stimulated to fabricate bioactive AgNPs using Mentha pulegium extract under alkaline conditions, accompanied by a systematic evaluation on the effect of biosynthesis parameters on the formation, average size, and polydispersity of AgNPs. Our results showed that alkaline conditions could accelerate the formation of AgNPs with a small average size but at a disadvantage to the polydispersity. Additionally, the as-prepared AgNPs had a hexagonal structure and spherical shape with an average size of 15.7 ± 0.1 nm, existing in the monodispersed form and revealing a high degree of stability. The AgNPs exhibited potent antioxidant and significant inhibitory activity for both bacterial and cancer cell lines. The MIC values of AgNPs for Staphylococcus aureus and Escherichia coli were both 50.0 μg·mL–1, and the IC50 values for HCT116, HepG2, and HeLa cells were 9.0, 14.5, and 31.5 μg·mL–1, respectively. The AgNPs biosynthesized using M. pulegium under alkaline conditions, which had a smaller size and more surface loads, are entirely different with those synthesized under acidic conditions, and the anticancer activity increased significantly. The internalization of AgNPs inside these five cells displayed a variant trend with variable AgNPs concentrations, suggesting the different mechanism of cell death. For two pathogens, HCT116 and HepG2 cancer cell lines, both cell wall and intracellular damage may be responsible for the cell death. However, for Hela cell line the cell death may be rooted in oxidative stress or intracellular penetration. These results confirmed that the AgNPs biosynthesized from M. pulegium extract under alkaline conditions would act as better anticancer agents in biomedicine.

Green synthesis of Ag nanoparticles from Leucus aspera and its application in anticancer activity against alveolar cancer

Leucus aspera is a perennial plant traditionally used as an herbal medicine in many countries. The biosynthesis of metal nanoparticles using medicinal plants is not only economical but also environmentally friendly as well as having miscellaneous biomedical applications. In this study, Leucus aspera extract as a stabilising and reducing agent was utilised to synthesise Ag nanoparticles in the aqueous medium. In addition, the anti-alveolar cancer property of AgNPs was investigated in the in vitro condition. Various techniques containing UV–Vis. spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDS) were used to characterise the synthesised nanoparticles. On the other hand, the MTT assay was run to evaluate the cytotoxicity activity of AgNPs. The crystal size of AgNPs, according to the XRD analysis, was 34.22 nm. Moreover, the uniform spherical morphology ranging from 40.67 to 58.17 nm was detected in the SEM images for the biosynthesised nanoparticles. In the antioxidant test, the IC50 of AgNPs and BHT against DPPH free radicals were 87 and 41 µg/mL, respectively. The synthesised nanocomposite had very low cell viability and high anti-alveolar cancer activities against A549 cell line without any cytotoxicity on the normal cell line (HUVEC). The viability of malignant alveolar cell line reduced dose-dependently in the presence of Ag NPs. Perhaps notable anti-alveolar cancer activities of the synthesised nanocomposite against common alveolar cancer cell line are linked to their antioxidant activities.

Hyperspectral microscopy of subcutaneously released silver nanoparticles reveals sex differences in drug distribution

Biomaterials have a great potential to improve human health, however in vitro and in vivo studies are necessary to provide information on their efficacy and safety. This study reports on a comprehensive evaluation of core-shell electrospun fibers loaded with silver nanoparticles (Ag NP) where the delivery rate was controlled by different sizes of Ag NP and thermoresponsive poly(n-isopropylacrylamide) (PNIPAM) hydrogel particles. Fiber meshes also contain zinc oxide nanoparticles (ZnO NP), to improve pore structure for controlled release of Ag NP. In vitro cytotoxicity studies using cultured human A549 epithelial cells demonstrated that the ZnO NP component, which is known to cause cytotoxicity, of the fiber meshes did cause measurable cell death. In vitro antibacterial efficacy of the fiber meshes was shown with rapid and efficient growth inhibition in E. coli bacterial culture. Fiber meshes were implanted subcutaneously for up to 27 days in male and female C57BL/6 mice to evaluate the in vivo drug release and biocompatibility. Hyperspectral microscopy was used as an advanced tool to determine precise location of released Ag NP into the skin compared to the conventional tissue staining methods. Results suggested that Ag NP were continuously released over 27 days of implantation in mice. Hyperspectral imaging revealed that released Ag NP dispersed in the dermis of male mice, however, Ag NP accumulated in the hair follicles of female mice (Figure). Mice implanted with fiber meshes containing ZnO NP had better hair regrowth and wound healing, which was in contrast to in vitro cytotoxicity results. These findings suggest that these newly developed fiber meshes can have unique long-term release of drugs loaded in the fiber core and appear to be biocompatible. The differences in the sex-bias outcome suggest the opportunity for development of sex-specific drug delivery systems.

Sustainable fabrication of silver-titania nanocomposites using goji berry (Lycium barbarum L.) fruit extract and their photocatalytic and antibacterial applications

• Green synthesis of metal nanocomposites is sustainable and environmentally friendly. • Silver-titania nanocomposites (Ag-TiO 2 NCs) were synthesized using the aqueous extract of goji berries. • FE-TEM morphology shows the embedment of Ag-NPs throughout the surface of TiO 2 -NPs. • Ag-TiO 2 NC (3:1) exhibited the highest photocatalytic degradation of methylene blue. • NCs exhibited potential antibacterial properties against S. aureus and E. coli bacteria. Silver-titania nanocomposites (Ag-TiO 2 NCs) have unique functional attributes due to their photocatalytic and antibacterial properties. In this study, titania nanoparticles (TiO 2 -NPs) were successfully in-situ decorated with silver nanoparticles (Ag-NPs) using the aqueous extract of goji berries (Lycium barbarum L . ) as a bioreducing and stabilizing agent. Different Ag-TiO 2 NCs were synthesized by treating different concentrations of silver nitrate with a specific concentration of TiO 2 -NPs in the presence of fruit extract. The green-synthesized NCs were characterized using several techniques viz., ultraviolet–visible spectrophotometry, X-ray diffractometry (XRD), scanning electron microscopy, field-emission transmission electron microscopy (FE-TEM), Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. XRD analysis revealed the formation of face-centered cubic (fcc) crystals, and FE-TEM analysis revealed the embedment of Ag-NPs throughout the surface of TiO 2 -NPs. The average size of Ag-NPs on TiO 2 -NPs increased from 11.2 ± 3.05 nm to 16.4 ± 4.5 nm with an increase in the concentration of silver ions, and the morphology of Ag-NPs was predominantly quasi-spherical and hexagonal. These NCs exhibited an excellent photocatalytic degradation of an azo dye, methylene blue (MB). The synthesized Ag-TiO 2 NCs (3:1) showed higher photocatalytic degradation efficiency of ∼ 93.4% for MB in 130 min under visible light irradiation. Ag-TiO 2 NC S also exhibited good antibacterial activities towards Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). Therefore, the formation of Ag-NPs on the surface of TiO 2 -NPs to form Ag-TiO 2 NCs exhibits eco-friendly photocatalytic degradation of azo dye contaminants as well as antibacterial activity.

Silver Nanoparticle-Decorated Silica Nanospheres and Arrays as Potential Substrates for Surface-Enhanced Raman Scattering.

Poly(vinylpyrrolidone) (PVP) was used as both a modifier and reductant to in situ deposit silver nanoparticles (denoted Ag NPs) on the surface of silica nanospheres (nanosilica or nano-SiO2), affording Ag-decorated nanosilica (denoted SiO2@Ag). The as-obtained SiO2@Ag composite can form silver nanoparticle-decorated silica nanosphere arrays (denoted SiO2@Ag arrays) via evaporation-induced self-assembly. The as-prepared SiO2@Ag composite and SiO2@Ag array were used as the SERS substrates to measure the Raman signals of the dilute solutions of rhodamine 6G (denoted R6G), an organic dye that is a potential pollutant to the environment. The findings indicate that the as-prepared SiO2@Ag composite and SiO2@Ag array as potential SERS substrates simultaneously exhibit a high degree of metal coverage and small size of Ag NPs as well as good stability and abundant “hot spots”, which contributes to their desired Raman enhancement capacities. For the detection of trace R6G, they provide a limit of detection of as low as 10–9–10–11 M as well as good reproducibility, showing promising potential for monitoring chemical and biological molecules.

ZnO, TiO2 and Ag nanoparticles impact against some species of pathogenic bacteria and yeast.

The economic approaches for manufacturing the nanoparticles with physical and chemical effects and limited resistance to antibiotics have been progressed recently due to the rise of microbial resistance to antibiotics. This research aimed to study the antimicrobial efficacy of silver nanoparticles Ag, ZnO, and Tio2 nanoparticles against Salmonella typhimurium and Brucella abortus and Candida albicans. Two isolates of Salmonella and two isolates of Brucella abortus were isolated from food spastically meat and blood specimens, respectively. Candida albicans were isolated from the patient's mouth with oral candidiasis (oral thrush) and confirmed diagnosis by API 20C test. The antimicrobial susceptibility of Salmonella typhimurium and B. abortus isolates were performed against nine different antibiotics. Silver nanoparticles consisting of AgNPs size (90) nm, ZnO NPs size (20, 50) nm as well as TiO2 NPs size (10, 50) nm, were used. UV-Visible spectrophotometer was used to characterize silver nanoparticles. The highest resistance of Candida albicans was seen for fluconazole, Clotrimazole and Itraconazole. The results of the Minimum Inhibitory Concentration (MIC) of nanoparticles against Salmonella typhimurium showed the average MIC of Tio2-10nm and Tio2-50nm were 5000 and 2500 μg\ml for S1 and S2 isolates, respectively. The isolated Brucella abortus (B1 and B2) showed sensitivity to NPs with different MIC. The average MIC for Ag-90nm was 5000 and 2500 µg/ml for B1 and B2 isolates, respectively. The findings suggest NP solution has fungicidal and bactericidal impacts on the tested microorganisms so they can be suitable for multiple applications of the biomedical field such as developing new antimicrobial agents.

Impact of polyvinylpyrrolidone and quantity of silver nitrate on silver nanoparticles sizing via solvothermal method for dye‐sensitized solar cells

The multiple sizing of silver nanoparticles (AgNPs) were synthesized from the miscible compound of ethylene glycol (EG), polyvinylpyrrolidone (PVP) and silver nitrate (AgNO3) via the solvothermal method. During the synthesis, the PVP‐AgNO3 was contemplated as a paramount parameter. Using the simple method of solvothermal, the sizing of AgNPs was easily controlled in accord with the augmentation of PVP‐AgNO3 at secured and moderate temperature. In regards to the sizing of AgNPs, the presence of minimum agglomeration, the absorption capability and chemical structures were highlighted through a series of verification includes ultraviolet–visible (UV–Vis) spectroscopy, Fourier‐transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) analysis. The effectiveness of the synthesized AgNPs was further investigated and compared with the commercial AgNPs by incorporating the AgNPs into titanium dioxide (TiO2) semiconductor film‐based dye‐sensitized solar cells (DSSCs). Results signified that the spherical AgNPs with produced sizing within the range of 19.6 to 45.2 nm were greatly impacting by tunable quantities of PVP‐AgNO3, which was validated in the forms of linear equations. A larger size promotes a slower nucleation rate that conduces agglomeration. In opposition to this, the smallest size of AgNPs develops a faster formation rate of Ag ions into AgNPs, inducing the deterrent of agglomeration in light of notable particle dispersion. The power conversion efficiency (PCE) contributed by the incorporation of synthesized AgNPs into TiO2 is also 41.2% higher than that of the commercial AgNPs‐TiO2. This is because the synthesized AgNPs provides less agglomeration which led to a better surface plasmonic effect towards the nanoparticles.

Effect of Stabilizers in the Synthesis of Silver Nanoparticles and Methylene Blue Oxidation

Metal nanocatalysts have received increasing attention in catalysis due to their higher reactivity and surface area-to-volume ratio at nano-size. Silver nanoparticle (AgNP) is among metal nanocatalysts that have been studied in various catalytic reactions (e.g., hydrogenation and oxidation). However, the high reactivity of AgNPs at nano-size caused instability and aggregation. Therefore, stabilizing molecules (or stabilizers) are always applied to maintain the nano size of AgNPs and prevent aggregation. Herein, the effects of different types and molar ratio of stabilizers-to-Ag precursor, to the synthesized AgNPs (i.e, size and concentration) were investigated. Two types of stabilizers, polyvinylpyrrolidone (PVP) and citrate were used in this study. The roles of stabilizers to the catalytic performance of synthesized AgNPs were then elucidated by using methylene blue oxidation as the model reaction. The UV-Vis absorption analyses showed that both stabilizers produced slightly different size and concentration of AgNPs based on the different wavelength and absorption intensity of the peak. We also found that the molar ratio of stabilizers-to-Ag precursor that produced better yield of AgNPs was 1:1 and 1:3 for PVP and citrate, respectively. Then, AgNPs stabilized by citrate was found having slightly higher catalytic activity in the methylene blue oxidation than AgNPs stabilized by PVP. This study provides insights to the roles of stabilizers for the synthesis of stable AgNPs with efficient catalytic reaction and can be used as guideline to other metal nanocatalysts.

Fruit Derived Potentially Bioactive Bioengineered Silver Nanoparticles.

IntroductionProtein-derived biogenic syntheses of inorganic nanoparticles have gained immense attention because of their broad spectrum of applications. Proteins offer a reducing environment to enable the synthesis of nanoparticles and encapsulate synthesized nanoparticles and provide them temporal stability in addition to biocompatibility.MethodsIn the present study, Benincasa hispida fruit proteins were used to synthesize silver nanoparticles (AgNPs) at 37 °C over five days of incubation. The synthesis of AgNPs was confirmed by UV-Vis spectroscopy, TEM, zeta potential, and DLS analyses. Further, these NPs depicted antibacterial and antibiofilm effects. Additionally, the anticancer activities of nanoparticles were also tested against the lung cancer cell line (A549) with respect to the normal cell line (NRK) using MTT assay. Further, the estimation of ROS generation through DCFH-DA staining along with a reduction in mitochondrial membrane potential by Mito Tracker Red CMX staining was carried out. Moreover, nuclear degradation in the AgNPs treated cells was cross-checked by DAPI staining.ResultsThe average size of AgNPs was detected to be 27 ±1 nm by TEM analysis, whereas surface encapsulation by protein was determined by FTIR spectroscopy. These NPs were effective against bacterial pathogens such as Escherichia coli, Staphylococcus aureus, Salmonella enteric, and Staphylococcus epidermis with MICs of 148.12 µg/mL, 165.63 µg/mL, 162.77 µg/mL, and 124.88 µg/mL, respectively. Furthermore, these nanoparticles inhibit the formation of biofilms of E. coli, S. aureus, S. enteric, and S. epidermis by 71.14%, 73.89%, 66.66%, and 64.81%, respectively. Similarly, these nanoparticles were also found to inhibit (IC50 = 57.11 µM) the lung cancer cell line (A549). At the same time, they were non-toxic against NRK cells up to a concentration of 200 µM.DiscussionWe successfully synthesized potentially potent antibacterial, antibiofilm and anticancer biogenic AgNPs.

Preparation and characterization of graphene nanosheet doped with silver nanoparticles

Simple process (exploding wire technique) was used to Prepared sliver nanoparticles (AgNPs). The graphene sheet was added to AgNPs with different concentrations (0.002g/ml and 0.01g/ml). well dispersion of AgNPs are achieved by simple chemistry process. The samples were characterized by ultraviolet-visible spectroscopy (UV-Vis), x-ray diffraction (XRD), atomic force microscopy (AFM) and Field emission scanning electron microscope (FESEM). The results showed a wide band absorption of AgNPs-graphene (AgNPs-GN) extended from VU to IR region, surface plasmon resonance (SPR) absorption peak position for the AgNPs at (350-600) nm, XRD confirmed the clear distribution of the peaks attributed to polycrystalline for AgNPs appeared at 20=38.14°, 44.27°, 64.33, and 77.37° respectively and AgNPs-GN at 2θ=26.51° and 54.65°. The AFM showed that AgNPs have uniformly distribution on the surface of graphene sheet. The average size of AgNPs was confirmed by around (50-80) nm by FESEM and the AgNPs-GN have average particle size (20-40) nm. The AgNPs-GN could become prominent candidate for optoelectronic applications.

Incubation media modify silver nanoparticle toxicity for whitefish (Coregonus lavaretus) and roach (Rutilus rutilus) embryos

ABSTRACT Toxicological studies were performed to examine silver nanoparticle (AgNP, size: 14.4 ± 2.5 nm) transformation within three different test media and consequent effects on embryos of whitefish (Coregonus lavaretus) and roach (Rutilus rutilus). The test media, namely ASTM very hard water, ISO standard dilution medium, and natural lake water differed predominantly in ionic strength. Total silver was determined using inductively coupled plasma mass spectrometry (ICP-MS), while AgNPs were characterized by transmission electron microscopy and single particle ICP-MS. Silver species distributions were estimated via thermodynamic speciation calculations. Data demonstrated that increased AgNP dissolution accompanied by decreasing ionic strength of the test medium did not occur as noted in other studies. Further, other physicochemical parameters including AgNP size and metallic species distribution did not markedly affect AgNP-induced toxicity. Irrespective of the test medium, C. lavaretus were more sensitive to AgNP exposure (median lethal concentration after 8 weeks: 0.51–0.73 mg/L) compared to R. rutilus, where adverse effects were only observed at 5 mg/L in natural lake water. In addition, AgNP-induced toxicity was lower in the two standard test media compared to natural lake water. Currently, there are no apparent studies assessing simultaneously the sensitivity of C. lavaretus and R. rutilus to AgNP exposure. Therefore, the aim of this study was to (1) investigate AgNP-induced toxicity in C. lavaretus and R. rutilus cohabiting in the same aquatic environment and (2) the role played by test media in the observed effects of AgNPs on these aquatic species.

Green Synthesis and Characterization of Silver Nanoparticles from Stem Bark Extract of Cordia dichotoma G. Forst and Evaluation of their Antioxidant and Antibacterial activities Articles

Pharmacognosy Research,2021,13,3,158-164.DOI:10.5530/pres.13.3.8Published:June 2021Type:Original ArticleAuthors:Gone Swapna, and Bhattiprolu Kesava Rao Author(s) affiliations:Gone Swapna, Bhattiprolu Kesava Rao* Department of Chemistry, Acharya Nagarjuna University, Guntur, Andhra Pradesh, INDIA Abstract:Background: There is a lack of scientific evidence for the fabrication of silver nanoparticles (AgNPs) using stem bark extract of medicinal plant Cordia dichotoma and its potential therapeutic applications. Objectives: In our present study we contemplated using Cordia dichotoma extract for fabricating AgNPs and to analyze their potential applications as antioxidant and biocidal agents. Materials and Methods: AgNPs were fabricated by bio reduction of silver nitrate solution with bark extract of Cordia dichotoma. The fabricated AgNPs were characterized using U.V visible, FT-IR, XRD, SEM, EDAX, particle size analyzer, and zeta potential. Further, evaluated for their potential antioxidant activity and compared with the crude extract of Cordia dichotoma and with standard ascorbic acid. The antibacterial activity was performed against both Gram-positive and Gram-negative bacteria. Results: The AgNPs were synthesized and UV spectra showed maximum absorbance at 430nm, which is the characteristic feature of AgNPs. The XRD peaks at (111), (220), and (311) indicate the existence of silver with a crystalline structure. The FT-IR spectra in the range of 1516 to 1634 cm−1 reflected the presence of phenol groups which acted as the capping agents for synthesized AgNPs. The SEM images confirmed the spherical structure of AgNPs that formed aggregates with phytochemicals and appeared as composites. The average size of AgNPs is 39.8nm and exhibited good stability as evident from the zeta potential value of -33. Conclusion: Phytomediated eco-friendly synthesized and structurally characterized AgNPs can act as antioxidants and exhibited antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) pathogenic bacteria. Keywords:Antibacterials, Antioxidants, Cordia dichotoma, Silver nanoparticlesView:PDF (1.18 MB)

Comparative Analysis of Nanosilver Particles Synthesized by Different Approaches and Their Antimicrobial Efficacy

Silver nanoparticles (AgNPs) were extensively used in different fields worldwide. There is a continued increase in their productions to fulfill various uses. Biological and chemical AgNP syntheses were the most popular mechanisms in this field. Agrowastes are rich in proteins, phenolics, and flavonoids that could act as bioreductant agents in AgNP biological synthesis. The present study was aimed at synthesizing AgNPs via chemical and biological methods using trisodium citrate, pomegranate fruit peel, and coffee ground waste extracts. Moreover, silver nanoparticles were monitored by UV-vis spectroscopy and characterized using zeta potential, size distribution mean, scanning electron microscope (SEM), X-ray diffractometer (XRD), and Fourier transforms infrared spectroscopy (FTIR). Four pathogenic bacterial strains (Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, and MRSA) were used to assess the antimicrobial effect of the synthesized AgNPs (2, 4, and 8 mg/ml). Results report the successful formation of silver nanoparticles chemically (AgNPs_Chem) and biologically by using pomegranate peel extract (AgNPs_PPE) and coffee ground waste extract (AgNPs_CE) due to the change of color to dark brown that is confirmed by UV-vis sharp absorption spectra at specific wavelengths. Characterization using SEM and XRD revealed their crystalline shape with a mean size of AgNPs _ Chem = 62.75 , AgNPs _ CE = 273.7 nm , and AgNPs _ PPE = 591.9 nm . AgNPs_Chem show higher negativity of zeta potential (−46.7 mV) than AgNPs_CE (−12.6 mV), followed by AgNPs_PPE (−7.98 mV), which had the least stability. All the synthesized AgNPs show antimicrobial potential on all selected strains. However, 8 mg/ml shows the most effective concentration and has more efficiency on K. pneumoniae than others. Overall, the results highlight that the use of agrowastes could be an ecofriendly way to synthesize AgNPs biologically that have the same antimicrobial effect as the chemically synthesized AgNPs.

Synergistic effect of plant extract coupled silver nanoparticles in various therapeutic applications- present insights and bottlenecks

The phytocomponent conjugated silver nanoparticles (AgNPs) have been extensively explored for various therapeutic applications such as antimicrobial, antioxidant, anticancer, anti-inflammatory, antidiabetic and anticoagulant effects. The bio-conjugation of Ag-based nanomaterial with plant extracts reduces their toxicity to biological systems and enhances their therapeutic effectiveness. The diversity of phytochemicals or capping agents provided by the plant extracts and the small size and large surface area of AgNPs permits maximum adsorption of these capping agents onto their surfaces that further promote the therapeutic performance of phytoconjugated AgNPs in various biomedical applications. The mechanistic action involved in antimicrobial and anticancer functions of AgNPs is mainly dependent on the induction of reactive oxygen species (ROS) resulting in cellular apoptosis and necrosis. This review summarizes the recent studies of various plant extract assisted synthesis of AgNPs, potential biomedical applications with the possible mechanism of action and major shortcomings affecting their therapeutic efficacy.

Combination of AgNPs and Domiphen is Antimicrobial Against Biofilms of Common Pathogens.

PurposeThe aim was to evaluate the antimicrobial potential of AgNPs synthesized with Artemisia argyi leaf extract and investigate the antimicrobial synergistic effects of AgNPs combined with domiphen and provide an efficient and broad-spectrum combination drug strategy.MethodsAgNPs synthesized with Artemisia argyi leaf extract were studied using UV–vis spectroscopy, FTIR spectroscopy and particle size analysis. Then, Artemisia argyi leaf extract-synthesized AgNPs and domiphen were tested against Acinetobacter baumannii (ATCC 19606), Staphylococcus aureus (ATCC 6538), Escherichia coli (8099) and Candida albicans (ATCC 10231), respectively. Then, we explore synergistic antimicrobial effect and synergistic anti-biofilm effect through combined drug susceptibility test and combined drug minimum biofilm eradication concentration (MBEC50) test.ResultsCharacteristic absorption bands of AgNPs were found near 430 nm in the UV–vis spectrum. Particle size analysis results revealed that the average particle size of Artemisia argyi leaf extract-synthesized AgNPs was 77.6 nm. Artemisia argyi leaf extract-synthesized AgNPs showed high antimicrobial activity against the above four strains. Minimum inhibitory concentration (MIC) of Artemisia argyi leaf extract-synthesized AgNPs against strains was 1 μg/mL for Acinetobacter baumannii, 2 μg/mL for Staphylococcus aureus, Escherichia coli and Candida albicans. MBEC50 of Artemisia argyi leaf extract-synthesized AgNPs against strains was 2 μg/mL for Acinetobacter baumannii, 4 μg/mL for Staphylococcus aureus, 1/2 μg/mL for Escherichia coli and 2 μg/mL for Candida albicans. The combination of Artemisia argyi leaf extract-synthesized AgNPs and domiphen has synergistic antimicrobial effect and synergistic anti-biofilm effect. Fractional inhibitory concentration (FIC) was ≤0.5.ConclusionArtemisia argyi leaf extract-synthesized AgNPs had antimicrobial activity against the above four strains. The combination of Artemisia argyi leaf extract-synthesized AgNPs and domiphen has synergistic antimicrobial effects to reduce the dosage of each antimicrobial drugs. Artemisia argyi leaf extract-synthesized AgNPs and domiphen have synergistic anti-biofilm effects.

Fabrication of silver-coated PET track-etched membrane as SERS platform for detection of acetaminophen

In this study, silver nanoparticles (AgNPs) were immobilized on the surface of polyethylene terephthalate (PET) membrane using diethylenetriamine (DETA) as a chemical linker. The molecule of DETA was attached to the surface of PET via an amide bond following scission of the polyester ester bond on the PET surface. The AgNPs were immobilized on the surface of diethylenetriamine-modified PET membrane via a silver-nitrogen covalent bond. The silver-coated, DETA-modified and unmodified PET membranes were characterized by Fourier transform infrared (FTIR), x-ray photoelectron spectroscopy (XPS), ulltraviolet-visible spectroscopy (UV–Vis), and scanning electron microscopy (SEM). The results showed that the size of AgNPs also increased with time of immobilization. The percentage of elemental silver also increased with increase in time of immobilization of AgNPs on the surface of DETA-modified PET membrane. The AgNP-coated PET membrane was used as SERS platform to detect acetaminophen in water. The SERS results showed that acetaminophen molecules could be detected with high Raman scattering intensity arising from adsorption of acetaminophen molecules on the silver nanoparticles of the SERS platform.Graphical abstract

Microwave assisted biosynthesis of Borassus flabellifer fruit mediated silver and gold nanoparticles for dye reduction, antibacterial and anticancer activity

Biosynthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) employing Borassus flabellifer fruit (BFF) extract as reducing and stabilizing agent under microwave irradiation is demonstrated in the present work for the reduction of organic dyes and biological applications. Formation, structure, size, morphology and binding state of the as-synthesized nanoparticles were characterized by UV–vis spectrophotometer, X-ray diffraction (XRD), Fourier transform infrared (FTIR), Dynamic light scattering (DLS), Transmission electron microscopy (TEM) techniques, and X-ray photoelectron spectroscopy (XPS). The presence of surface plasmon resonance (SPR) absorption band at 410 nm and 534 nm in UV-Visible spectra revealed the formation of AgNPs and AuNPs which was supported by XRD results. The average particle sizes of AgNPs and AuNPs with spherical morphology were in the range of ~ 7–9 nm and ~ 5–7 nm, respectively. The reduction of methylene blue (MB) and congo red (CR) dye was observed at faster rate over AgNPs and AuNPs with high selectivity and sensitivity. The biosynthesized NPs demonstrated potential antibacterial and anticancer properties on tested microorganisms and Human breast cancer (MCF-7) cells. The mechanism of the reduction of MB and CR dyes and biological activity over biosynthesized NPs are discussed. The facile and environmentally benign NPs could be a new alternative catalysts for toxic dye reduction and the proposed biological applications.

Optimization of hyphenated asymmetric flow field-flow fractionation for the analysis of silver nanoparticles in aqueous solutions

The extensive use of silver nanoparticles (AgNPs) in consumer products, medicine, and industry leads to their release into the environment. Thus, a characterization of the concentration, size, fate, and toxicity of AgNPs under environmental conditions is required. In this study, we present the characterization and optimization of an asymmetric flow field-flow fractionation (AF4) system coupled with UV/Vis spectrophotometer and dynamic light scattering (DLS) detector as a powerful tool for the size separation and multi-parameter characterization of AgNPs in complex matrices. The hyphenated AF4-UV/Vis-DLS system was first characterized using individual injections of the different size fractions. We used electrostatically stabilized AgNPs of 20-, 50-, and 80-nm nominal diameters coated with lipoic acid. We investigated the effect of applied cross-flows, carrier solutions, focus times, and quantity of injected particles on the nature of the AF4 fractograms and on the integrity of the AgNPs. Best size separation of a 1:1 mixture of 20- and 80-nm AgNPs was achieved using cross-flows of 0.5 and 0.7 mL/min with 1 mM NaCl and 0.05% v/v Mucasol as carrier solutions. We also researched the behavior of AgNPs in natural waters using the hyphenated AF4-UV/Vis-DLS system, under determined optimal conditions.Graphical abstractSchematic and photograph of the AF4 setup with numbered hardware devices. Dashed lines represent electrical connections; continuous lines represent fluidic connections. For a better overview, not all fluidic connections between pump/6-way valve (2) and the Eclipse AF4 device (3) are shown in the schematic. The fluorescence detector (FL (7)) was not used in the study presented herein.