Sample records for capped silver nanoparticles

  1. Capsaicin-capped silver nanoparticles: its kinetics, characterization and biocompatibility assay

    NASA Astrophysics Data System (ADS)

    Amruthraj, Nagoth Joseph; Preetam Raj, John Poonga; Lebel, Antoine

    2015-04-01

    Capsaicin was used as a bio-reductant for the reduction of silver nitrate to form silver nanoparticles. The formation of the silver nanoparticles was initially confirmed by color change and Tyndall effect of light scattering. It was characterized with UV-visible spectroscopy, FTIR and TEM. Hemagglutination (H) test and H-inhibition assay were performed in the presence of AgNPs-capsaicin conjugates. The silver colloid solution after complete reduction turned into pale gray color. The characteristic surface plasmon resonance of silver nanoparticles (SNPs) was observed at 450 nm. Time taken for complete bio-reduction of silver nitrate and capping was found to be 16 hours. The amount of capsaicin required to reduce 20 ml of 1 mM silver nitrate solution was found to be 40 ?g approximately. The FTIR results confirmed the capping of capsaicin on the silver metal. The particle size was within the range of 20-30 nm. The hemagglutination and H-inhibition test was negative for all the blood groups. The capsaicin-capped silver nanoparticles were compatible with blood cells in hemagglutination test implying biocompatibility as future therapeutic drug.

  2. Laser-fabricated castor oil-capped silver nanoparticles

    PubMed Central

    Zamiri, Reza; Zakaria, Azmi; Abbastabar, Hossein; Darroudi, Majid; Husin, Mohd Shahril; Mahdi, Mohd Adzir

    2011-01-01

    Silver nanoparticles were fabricated by ablation of a pure silver plate immersed in castor oil. A Nd:YAG-pulsed Q-switch laser with 1064-nm wavelength and 10-Hz frequency was used to ablate the plate for 10 minutes. The sample was characterized by ultraviolet-visible, atomic absorption, Fourier transform-infrared spectroscopies, and transmission electron microscopy. The results of the fabricated sample showed that the nanoparticles in castor oil were about 5-nm in diameter, well dispersed, and showed stability for a long period of time. PMID:21698083

  3. Biomimetic synthesis and characterisation of protein capped silver nanoparticles.

    PubMed

    Sanghi, Rashmi; Verma, Preeti

    2009-01-01

    A controlled and up-scalable route for the biosynthesis of silver nanopartilces (NPs) mediated by fungal proteins of Coriolus versicolor has been undertaken for the first time. The fungus when challenged with silver nitrate solution accumulated silver NPs on its surface in 72h which could be reduced to 1h by tailoring the reaction conditions. Under alkaline conditions, the reaction was much faster and could easily proceed at room temperature even without stirring. The resulting Ag NPs displayed controllable structural and optical properties depending on the experimental parameters such as pH and reaction temperatures. The average size, morphology, and structure of particles were determined by AFM, TEM, XRD and UV/Visible absorption spectrophotometry. Fourier transform infrared study disclosed that the amino groups were bound to the particles, which was accountable for the stability of NPs. It further confirmed the presence of protein as the stabilizing and capping agent surrounding the silver NPs. Experiments were conducted both with, media in which fungus was initially harvested and that of pristine fungal mycelium alone. Under normal conditions, in the case of media extracellular synthesis took place whereby other than the fungal proteins, glucose was also responsible for the reduction. In the case of fungal mycelium, the intracellular formation of Ag NPs, could be tailored to give both intracellular and extracellular Ag NPs under alkaline conditions whereby the surface S-H groups of the fungus played a major role. PMID:18625550

  4. Synthesis, characterization and comparison of antimicrobial activity of PEG\\/TritonX-100 capped silver nanoparticles on collagen scaffold

    Microsoft Academic Search

    A. Mandal; V. Meda; W. J. Zhang; K. M. Farhan; A. Gnanamani

    Silver nanoparticles have received attention as novel antimicrobial agents. In order to study the effects of silver nanoparticles on both Gram positive and negative bacteria, the nanoparticles were synthesized via chemical reduction method using different concentrations (0.3, 0.6 and 0.9mM) of poly(ethylene) glycol (PEG) and TritonX-100 (TX). Also, mixed PEG\\/TX systems with equimolar concentrations capped silver nanoparticles were synthesized and

  5. Keratin capped silver nanoparticles - synthesis and characterization of a nanomaterial with desirable handling properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silver nanoparticles (NPs) were produced with keratin stabilizer and the NPs exhibited unimodal Gaussian distribution with average diameter of 3.5nm +/- 0.7 nm. The molecular mass of keratin stabilizer was 6-8 kDa. The mass of keratin capped NPs was >250 kDa to indicate the formation of crosslinked...

  6. Biocompatibility study of protein capped and uncapped silver nanoparticles on human hemoglobin

    NASA Astrophysics Data System (ADS)

    Bhunia, Amit Kumar; Kanti Samanta, Pijus; Aich, Debasish; Saha, Satyajit; Kamilya, Tapanendu

    2015-06-01

    The interactions of human hemoglobin with protein capped silver nanoparticles and bare silver nanoparticles were studied to understand fundamental perspectives about the biocompatibility of protein capped silver nanoparticles compared with bare silver nanoparticles. Bare silver (Ag) nanoparticles (NPs) were prepared by the chemical reduction method. High resolution transmission electron microscopy (HRTEM) analysis along with absorption at ~390?nm indicated the formation of bare Ag NPs. Protein coated Ag NPs were prepared by a green synthesis method. Absorption at ~440?nm along with ~280?nm indicated the formation of protein coated Ag NPs. The biocompatibility of the above mentioned Ag NPs was studied by interaction with human hemoglobin (Hb) protein. In presence of bare Ag NPs, the Soret band of Hb was red shifted. This revealed the distortion of iron from the heme pockets of Hb. Also, the fluorescence peak of Hb was quenched and red shifted which indicated that Hb became unfolded in the presence of bare Ag NPs. No red shift of the absorption of Soret, along with no shift and quenching of the fluorescence peak of Hb were observed in the presence of protein coated Ag NPs. A hemolysis assay suggested that protein coated Ag NPs were more biocompatible than bare one.

  7. Hydroxy propyl cellulose capped silver nanoparticles produced by simple dialysis process

    SciTech Connect

    Francis, L. [University of Genova, Department of Chemistry and Industrial Chemistry, via Dodecaneso 31, 16146 Genova (Italy)] [University of Genova, Department of Chemistry and Industrial Chemistry, via Dodecaneso 31, 16146 Genova (Italy); Balakrishnan, A. [Laboratoire SIMaP - GPM2, Grenoble-INP/UJF/CNRS BP46, 38042 Saint Martin d'Heres cedex (France)] [Laboratoire SIMaP - GPM2, Grenoble-INP/UJF/CNRS BP46, 38042 Saint Martin d'Heres cedex (France); Sanosh, K.P. [Department of Innovation Engineering, University of Lecce, via per Monteroni, 73100 Lecce (Italy)] [Department of Innovation Engineering, University of Lecce, via per Monteroni, 73100 Lecce (Italy); Marsano, E., E-mail: marsano@chimica.unige.it [University of Genova, Department of Chemistry and Industrial Chemistry, via Dodecaneso 31, 16146 Genova (Italy)

    2010-08-15

    Silver (Ag) nanoparticles ({approx}6 nm) were synthesized using a novel dialysis process. Silver nitrate was used as a starting precursor, ethylene glycol as solvent and hydroxy propyl cellulose (HPC) introduced as a capping agent. Different batches of reaction mixtures were prepared with different concentrations of silver nitrate (AgNO{sub 3}). After the reduction and aging, these solutions were subjected to ultra-violet visible spectroscopy (UVS). Optimized solution, containing 250 mg AgNO{sub 3} revealed strong plasmon resonance peak at {approx}410 nm in the spectrum indicating good colloidal state of Ag nanoparticles in the diluted solution. The optimized solution was subjected to dialysis process to remove any unreacted solvent. UVS of the optimized solution after dialysis showed the plasmon resonance peak shifting to {approx}440 nm indicating the reduction of Ag ions into zero-valent Ag. This solution was dried at 80 {sup o}C and the resultant HPC capped Ag (HPC/Ag) nanoparticles were studied using transmission electron microscopy (TEM) for their particle size and morphology. The particle size distribution (PSD) analysis of these nanoparticles showed skewed distribution plot with particle size ranging from 3 to 18 nm. The nanoparticles were characterized for phase composition using X-ray diffractrometry (XRD) and Fourier transform infrared spectroscopy (FT-IR).

  8. Hansen solubility parameters of surfactant-capped silver nanoparticles for ink and printing technologies.

    PubMed

    Petersen, Jacob B; Meruga, Jeevan; Randle, James S; Cross, William M; Kellar, Jon J

    2014-12-30

    Optimal ink formulations, inclusive of nanoparticles, are often limited to matching the nanoparticle's capping agent or surface degree of polarity to the solvent of choice. Rather than relying on this single attribute, nanoparticle dispersibility was optimized by identifying the Hansen solubility parameters (HSPs) of decanoic-acid-capped 5 nm silver nanoparticles (AgNPs) by broad spectrum dispersion testing and a more specific binary solvent gradient dispersion method. From the HSPs, solvents were chosen to disperse poly(methyl methacrylate) (PMMA) and nanoparticles, give uniform evaporation profiles, and yield a phase-separated microstructure of nanoparticles on PMMA via film formation by solvent evaporation. The goal of this research was to yield a film that is reflective or transparent depending on the angle of incident light (i.e., optically variable). The nanoparticle HSPs were very close to alkanes with added small polar and hydrogen-bonding components. This led to two ink formulations: one of 90:10 vol % toluene/methyl benzoate and one containing 80:10:10 vol % toluene/p-xylene/mesitylene, both of which yielded the desired final microstructure of a nanoparticle layer on a PMMA film. This approach to nanoparticle ink formulation allows one to obtain an ink that has desirable dispersive qualities, rheology, and evaporation to give a desired printed structure. PMID:25469943

  9. Formation of colloidal silver nanoparticles: Capping action of citrate

    SciTech Connect

    Henglein, A.; Giersig, M.

    1999-11-04

    Colloidal silver sols of long-time stability are formed in the {gamma}-irradiation of 1.0 x 10{sup {minus}4} M AgClO{sub 4} solutions, which also contain 0.3 M 2-propanol, 2.5 x 10{sup {minus}2} M N{sub 2}O, and sodium citrate in various concentrations. The reduction of Ag{sup +} in these solutions is brought about by the 1-hydroxyalkyl radical generated in the radiolysis of 2-propanol; citrate does not act as a reductant but solely as a stabilizer of the colloidal particles formed. Its concentration is varied in the range from 5.0 x 10{sup {minus}5} to 1.5 x 10{sup {minus}3} M, and the size and size distribution of the silver particles are studied by electron microscopy. At low citrate concentration, partly agglomerated large particles are formed that have many imperfections. In an intermediate range (a few 10{sup {minus}4} M), well-separated particles with a rather narrow size distribution and little imperfections are formed, the size slightly decreasing with increasing citrate concentration. At high citrate concentrations, large lumps of coalesced silver particles are present, due to destabilization by the high ionic strength of the solution. These findings are explained by two growth mechanisms: condensation of small silver clusters (type-1 growth), and reduction of Ag{sup +} on silver particles via radical-to-particle electron transfer (type-2 growth). The particles formed in the intermediate range of citrate concentration were studied by high-resolution electron microscopy and computer simulations. They constitute icosahedra and cuboctahedra.

  10. Synthesis and bioactivities of silver nanoparticles capped with 5-Amino-?-resorcylic acid hydrochloride dihydrate

    PubMed Central

    2014-01-01

    Background Conjugated and drug loaded silver nanoparticles are getting an increased attention for various biomedical applications. Nanoconjugates showed significant enhancement in biological activity in comparison to free drug molecules. In this perspective, we report the synthesis of bioactive silver capped with 5-Amino-?-resorcylic acid hydrochloride dihydrate (AR). The in vitro antimicrobial (antibacterial, antifungal), enzyme inhibition (xanthine oxidase, urease, carbonic anhydrase, ?-chymotrypsin, cholinesterase) and antioxidant activities of the developed nanostructures was investigated before and after conjugation to silver metal. Results The conjugation of AR to silver was confirmed through FTIR, UV¿vis and TEM techniques. The amount of AR conjugated with silver was characterized through UV¿vis spectroscopy and found to be 9% by weight. The stability of synthesized nanoconjugates against temperature, high salt concentration and pH was found to be good. Nanoconjugates, showed significant synergic enzyme inhibition effect against xanthine and urease enzymes in comparison to standard drugs, pure ligand and silver. Conclusions Our synthesized nanoconjugate was found be to efficient selective xanthine and urease inhibitors in comparison to Ag and AR. On a per weight basis, our nanoconjugates required less amount of AR (about 11 times) for inhibition of these enzymes. PMID:25201390

  11. Formation of colloidal silver nanoparticles: Capping action of citrate

    Microsoft Academic Search

    Arnim Henglein; Michael Giersig

    1999-01-01

    Colloidal silver sols of long-time stability are formed in the γ-irradiation of 1.0 x 10⁻⁴ M AgClOâ solutions, which also contain 0.3 M 2-propanol, 2.5 x 10⁻² M NâO, and sodium citrate in various concentrations. The reduction of Ag{sup +} in these solutions is brought about by the 1-hydroxyalkyl radical generated in the radiolysis of 2-propanol; citrate does not act

  12. Green synthesis of chondroitin sulfate-capped silver nanoparticles: characterization and surface modification.

    PubMed

    Cheng, Kuang-ming; Hung, Yao-wen; Chen, Cheng-cheung; Liu, Cheng-che; Young, Jenn-jong

    2014-09-22

    A one-step route for the green synthesis of highly stable and nanosized silver metal particles with narrow distribution is reported. In this environmentally friendly synthetic method, silver nitrate was used as silver precursor and biocompatible chondroitin sulfate (ChS) was used as both reducing agent and stabilizing agent. The reaction was carried out in a stirring aqueous medium at the room temperature without any assisted by microwave, autoclave, laser irradiation, ?-ray irradiation or UV irradiation. The transparent colorless solution was converted to the characteristics light red then deep red-brown color as the reaction proceeds, indicating the formation of silver nanoparticles (Ag NPs). The Ag NPs were characterized by UV-visible spectroscopy (UV-vis), photon correlation spectroscopy, laser Doppler anemometry, transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that the obtained metallic nanoparticles were Ag NPs capped with ChS. In this report, dynamic light scattering (DLS) was used as a routinely analytical tool for measuring size and distribution in a liquid environment. The effects of the reaction time, reaction temperature, concentration and the weight ratio of ChS/Ag+ on the particle size and zeta potential were investigated. The TEM image clearly shows the morphology of the well-dispersed ChS-capped Ag NPs are spherical in shape, and the average size (<20 nm) is much smaller than the Z-average value (76.7 nm) measured by DLS. Meanwhile, the ChS-capped Ag NPs coated with N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC) were prepared by an ionic gelation method and the surface charge of Ag NPs was switched from negative to positive. PMID:24906746

  13. Green synthesis of silk sericin-capped silver nanoparticles and their potent anti-bacterial activity

    NASA Astrophysics Data System (ADS)

    Aramwit, Pornanong; Bang, Nipaporn; Ratanavaraporn, Juthamas; Ekgasit, Sanong

    2014-02-01

    In this study, a `green chemistry' approach was introduced to synthesize silk sericin (SS)-capped silver nanoparticles (AgNPs) under an alkaline condition (pH 11) using SS as a reducing and stabilizing agent instead of toxic chemicals. The SS-capped AgNPs were successfully synthesized at various concentrations of SS and AgNO3, but the yields were different. A higher yield of SS-capped AgNPs was obtained when the concentrations of SS and AgNO3 were increased. The SS-capped AgNPs showed a round shape and uniform size with diameter at around 48 to 117 nm. The Fourier transform infrared (FT-IR) spectroscopy result proved that the carboxylate groups obtained from alkaline degradation of SS would be a reducing agent for the generation of AgNPs while COO- and NH2 + groups stabilized the AgNPs and prevented their precipitation or aggregation. Furthermore, the SS-capped AgNPs showed potent anti-bacterial activity against various gram-positive bacteria (minimal inhibitory concentration (MIC) 0.008 mM) and gram-negative bacteria (MIC ranging from 0.001 to 0.004 mM). Therefore, the SS-capped AgNPs would be a safe candidate for anti-bacterial applications.

  14. Green synthesis of silk sericin-capped silver nanoparticles and their potent anti-bacterial activity

    PubMed Central

    2014-01-01

    In this study, a ‘green chemistry’ approach was introduced to synthesize silk sericin (SS)-capped silver nanoparticles (AgNPs) under an alkaline condition (pH 11) using SS as a reducing and stabilizing agent instead of toxic chemicals. The SS-capped AgNPs were successfully synthesized at various concentrations of SS and AgNO3, but the yields were different. A higher yield of SS-capped AgNPs was obtained when the concentrations of SS and AgNO3 were increased. The SS-capped AgNPs showed a round shape and uniform size with diameter at around 48 to 117 nm. The Fourier transform infrared (FT-IR) spectroscopy result proved that the carboxylate groups obtained from alkaline degradation of SS would be a reducing agent for the generation of AgNPs while COO? and NH2?+ groups stabilized the AgNPs and prevented their precipitation or aggregation. Furthermore, the SS-capped AgNPs showed potent anti-bacterial activity against various gram-positive bacteria (minimal inhibitory concentration (MIC) 0.008 mM) and gram-negative bacteria (MIC ranging from 0.001 to 0.004 mM). Therefore, the SS-capped AgNPs would be a safe candidate for anti-bacterial applications. PMID:24533676

  15. Green synthesis of silk sericin-capped silver nanoparticles and their potent anti-bacterial activity.

    PubMed

    Aramwit, Pornanong; Bang, Nipaporn; Ratanavaraporn, Juthamas; Ekgasit, Sanong

    2014-01-01

    In this study, a 'green chemistry' approach was introduced to synthesize silk sericin (SS)-capped silver nanoparticles (AgNPs) under an alkaline condition (pH 11) using SS as a reducing and stabilizing agent instead of toxic chemicals. The SS-capped AgNPs were successfully synthesized at various concentrations of SS and AgNO3, but the yields were different. A higher yield of SS-capped AgNPs was obtained when the concentrations of SS and AgNO3 were increased. The SS-capped AgNPs showed a round shape and uniform size with diameter at around 48 to 117 nm. The Fourier transform infrared (FT-IR) spectroscopy result proved that the carboxylate groups obtained from alkaline degradation of SS would be a reducing agent for the generation of AgNPs while COO- and NH2?+ groups stabilized the AgNPs and prevented their precipitation or aggregation. Furthermore, the SS-capped AgNPs showed potent anti-bacterial activity against various gram-positive bacteria (minimal inhibitory concentration (MIC) 0.008 mM) and gram-negative bacteria (MIC ranging from 0.001 to 0.004 mM). Therefore, the SS-capped AgNPs would be a safe candidate for anti-bacterial applications. PMID:24533676

  16. Synthesis, characterization and comparison of antimicrobial activity of PEG/TritonX-100 capped silver nanoparticles on collagen scaffold.

    PubMed

    Mandal, A; Meda, V; Zhang, W J; Farhan, K M; Gnanamani, A

    2012-02-01

    Silver nanoparticles have received attention as novel antimicrobial agents. In order to study the effects of silver nanoparticles on both Gram positive and negative bacteria, the nanoparticles were synthesized via chemical reduction method using different concentrations (0.3, 0.6 and 0.9 mM) of poly(ethylene) glycol (PEG) and TritonX-100 (TX). Also, mixed PEG/TX systems with equimolar concentrations capped silver nanoparticles were synthesized and confirmed by UV-vis, fluorescence spectroscopy and particle size analysis. These coated silver nanoparticles were incorporated into collagen, lyophilized to form scaffolds and characterized by SEM, XRD, ATR-FTIR, DSC, TGA and zeta potential. Results on mechanical property of all the scaffolds displayed no significant difference in the percentage elongation at break. However, the maximum percentage of 46.67% was observed with the combinations (0.9 mM PEG+0.9 mM TX). This implies that the combinations of surfactants increase the elasticity, which is useful for biomedical applications, e.g., heart-valve preparations. Furthermore, the antimicrobial activities of these capped silver nanoparticles homogenized with collagen were tested against both Gram positive and negative bacteria. Minimum inhibitory concentration values obtained for the combination (0.9 mM PEG+0.9 mM TX) were found to be better than others and thus provide strong antibacterial property to the collagen scaffolds prepared for tissue regeneration applications. PMID:22063757

  17. In situ fabrication of photocurable conductive adhesives with silver nano-particles in the absence of capping agent

    Microsoft Academic Search

    Wen-Tung Cheng; Yu-Wen Chih; Wei-Ting Yeh

    2007-01-01

    To increase electrical conductivity and reduce number of processes, this paper aims to fabricate in situ photocurable conductive adhesives with Ag nano-particles in the absence of polymeric protector. The mixture of epoxy–acrylic resin and reactive monomer, as well as AgNO3 in ethylene glycol, is irradiated by UV light to form silver nano-particles without capping agent and was followed by adding

  18. Gamma irradiation route to synthesis of highly re-dispersible natural polymer capped silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Rao, Y. N.; Banerjee, D.; Datta, A.; Das, S. K.; Guin, R.; Saha, A.

    2010-12-01

    Aqueous dispersions of highly stable, redispersible silver nanoparticles (Ag NPs) were synthesized using gamma radiolysis with gum acacia as a protecting agent. The formation of nanosized silver was confirmed by its characteristic surface plasmon absorption peak at around 405 nm in UV-vis spectra. The size of the silver nanoparticles can be tuned by controlling the radiation dose, ratio of gum acacia to silver ions and also the ionic strength of the medium. Dynamic light scattering (DLS) measurement of the as-synthesized nanoparticles indicated the size less than 3 nm at higher dose of radiation and this also corroborated the size measurement from the width of the corresponding X-ray diffraction (XRD) peak. The face centered cubic (fcc) crystallinity of the nanoparticles was evident from XRD and high resolution transmission electron microscopic (HRTEM) measurements. Fourier transform infra-red (FTIR) spectroscopic data indicate a bonding of Ag NPs with COO - group of acacia through bridging bidentate linkage.

  19. Enhancement of Antibacterial Activity of Capped Silver Nanoparticles in Combination with Antibiotics, on Model Gram-Negative and Gram-Positive Bacteria

    PubMed Central

    Kora, Aruna Jyothi; Rastogi, Lori

    2013-01-01

    The nanoparticles used in this study were prepared from AgNO3 using NaBH4 in the presence of capping agents such as citrate, sodium dodecyl sulfate, and polyvinylpyrrolidone. The formed nanoparticles were characterized with UV-Vis, TEM, and XRD. The generation of silver nanoparticles was confirmed from the appearance of yellow colour and an absorption maximum between 399 and 404?nm. The produced nanoparticles were found to be spherical in shape and polydisperse. For citrate, SDS, and PVP capped nanoparticles, the average particle sizes were 38.3 ± 13.5, 19.3 ± 6.0, and 16.0 ± 4.8?nm, respectively. The crystallinity of the nanoparticles in FCC structure is confirmed from the SAED and XRD patterns. Also, the combined antibacterial activity of these differently capped nanoparticles with selected antibiotics (streptomycin, ampicillin, and tetracycline) was evaluated on model Gram-negative and Gram-positive bacteria, employing disc diffusion assay. The activity of the tested antibiotics was enhanced in combination with all the stabilized nanoparticles, against both the Gram classes of bacteria. The combined effects of silver nanoparticles and antibiotics were more prominent with PVP capped nanoparticles as compared to citrate and SDS capped ones. The results of this study demonstrate potential therapeutic applications of silver nanoparticles in combination with antibiotics. PMID:23970844

  20. Ultrasound assisted green synthesis of poly(vinyl alcohol) capped silver nanoparticles for the study of its antifilarial efficacy

    NASA Astrophysics Data System (ADS)

    Saha, Swadhin Kr.; Chowdhury, Pranesh; Saini, Prasanta; Babu, Santi P. Sinha

    2014-01-01

    Poly(vinyl alcohol) (PVA) capped stable silver nanoparticles (AgNP) have been synthesized sonochemically with the help of catalytic amount of a biomolecule (tyrosine). An attempt has been made to reduce the harmfull chemical additives (like sodium borohydride, hydrazine, dimethyl formamide, etc.) used in conventional methods. Tyrosine shows excellent reducing activity in presence of PVA stabilizer. Ultra-sound increased the reaction rate and yield, and improved the quality of the AgNP in terms of regular size distribution. The synthetic route follows the principles of green chemistry. Bioactivity has been tested in the light of antifilarial efficacy through induction of apoptosis. The biocompatible polymer (PVA) capped AgNPs are suitable for the treatment of filarial nematode.

  1. Ultrastable silver nanoparticles.

    PubMed

    Desireddy, Anil; Conn, Brian E; Guo, Jingshu; Yoon, Bokwon; Barnett, Robert N; Monahan, Bradley M; Kirschbaum, Kristin; Griffith, Wendell P; Whetten, Robert L; Landman, Uzi; Bigioni, Terry P

    2013-09-19

    Noble-metal nanoparticles have had a substantial impact across a diverse range of fields, including catalysis, sensing, photochemistry, optoelectronics, energy conversion and medicine. Although silver has very desirable physical properties, good relative abundance and low cost, gold nanoparticles have been widely favoured owing to their proved stability and ease of use. Unlike gold, silver is notorious for its susceptibility to oxidation (tarnishing), which has limited the development of important silver-based nanomaterials. Despite two decades of synthetic efforts, silver nanoparticles that are inert or have long-term stability remain unrealized. Here we report a simple synthetic protocol for producing ultrastable silver nanoparticles, yielding a single-sized molecular product in very large quantities with quantitative yield and without the need for size sorting. The stability, purity and yield are substantially better than those for other metal nanoparticles, including gold, owing to an effective stabilization mechanism. The particular size and stoichiometry of the product were found to be insensitive to variations in synthesis parameters. The chemical stability and structural, electronic and optical properties can be understood using first-principles electronic structure theory based on an experimental single-crystal X-ray structure. Although several structures have been determined for protected gold nanoclusters, none has been reported so far for silver nanoparticles. The total structure of a thiolate-protected silver nanocluster reported here uncovers the unique structure of the silver thiolate protecting layer, consisting of Ag2S5 capping structures. The outstanding stability of the nanoparticle is attributed to a closed-shell 18-electron configuration with a large energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, an ultrastable 32-silver-atom excavated-dodecahedral core consisting of a hollow 12-silver-atom icosahedron encapsulated by a 20-silver-atom dodecahedron, and the choice of protective coordinating ligands. The straightforward synthesis of large quantities of pure molecular product promises to make this class of materials widely available for further research and technology development. PMID:24005327

  2. Integrated approach to evaluating the toxicity of novel cysteine-capped silver nanoparticles to Escherichia coli and Pseudomonas aeruginosa.

    PubMed

    Priester, John H; Singhal, Aditi; Wu, Binghui; Stucky, Galen D; Holden, Patricia A

    2014-03-01

    Because of microbial resistance to conventional antibiotics, there is increasing interest in silver, including silver nanoparticles (nano-Ag), in antimicrobial applications. However, questions remain regarding the relative roles of nano-Ag particles, versus Ag(+) ions released from nano-Ag dissolution, in imparting bacterial toxicity. Here, we developed a novel nano-Ag that, based on its cysteine cap, was expected to dissolve slowly and thus potentially allow for differentiating nanoparticle, versus ionic, effects of Ag. The nano-Ag was systematically tested for its differential toxicity to Escherichia coli and Pseudomonas aeruginosa. Bacterial growth, reactive oxygen species (ROS) generation, particle dissolution, cellular electron transfer activity, and cell membrane damage and potential were evaluated. In minimal growth medium, E. coli and P. aeruginosa growth were slowed at 100 mg L(-1) (0.93 mM) and 5 mg L(-1) (0.046 mM), respectively; P. aeruginosa was completely inhibited at and above 10 mg L(-1) (0.093 mM). For both strains, toxicity was associated with ROS and cell membrane damage. Based on comparisons to AgNO3 exposures, toxicity from nano-Ag was due to Ag(+) ions and not intact nano-Ag, even though nanoparticle dissolution was less than 2% in minimal growth medium. Because of their stability and slow Ag(+) ion release, the cysteine-capped nano-Ag particles here are useful to antimicrobial applications. Additionally, our systematic approach to evaluating toxicity, membrane damage, and ROS generation can be applied with other nanomaterials and bacteria. PMID:24343373

  3. Toxicity of Citrate-Capped Silver Nanoparticles in Common Carp (Cyprinus carpio)

    PubMed Central

    Lee, Byoungcheun; Duong, Cuong Ngoc; Cho, Jaegu; Lee, Jaewoo; Kim, Kyungtae; Seo, Youngrok; Kim, Pilje; Choi, Kyunghee; Yoon, Junheon

    2012-01-01

    Juvenile common carp (Cyprinus carpio) were used as a model to investigate acute toxicity and oxidative stress caused by silver nanoparticles (Ag-NPs). The fish were exposed to different concentrations of Ag-NPs for 48 h and 96 h. After exposure, antioxidant enzyme levels were measured, including glutathione-S-transferase (GST), superoxidase dismutase, and catalase (CAT). Other biochemical parameters and histological abnormalities in different tissues (i.e., the liver, gills, and brain) were also examined. The results showed that Ag-NPs agglomerated in freshwater used during the exposure experiments, with particle size remaining <100?nm. Ag-NPs had no lethal effect on fish after 4 days of exposure. Biochemical analysis showed that enzymatic activities in the brain of the fish exposed to 200??g/L of Ag-NPs were significantly reduced. Varied antioxidant enzyme activity was recorded in the liver and gills. Varied antioxidant enzyme activity was recorded for CAT in the liver and GST in the gills of the fish. However, the recovery rate of fish exposed to 200??g/L of Ag-NPs was slower than when lower particle concentrations were used. Other biochemical indices showed no significant difference, except for NH3 and blood urea nitrogen concentrations in fish exposed to 50??g/L of Ag-NPs. This study provides new evidence about the effects of nanoparticles on aquatic organisms. PMID:23093839

  4. Poly(ethylene) glycol-capped silver and magnetic nanoparticles: synthesis, characterization, and comparison of bactericidal and cytotoxic effects.

    PubMed

    Mandal, A; Sekar, S; Chandrasekaran, N; Mukherjee, A; Sastry, T P

    2013-11-01

    Silver and magnetic (Fe3O4) nanoparticles have attracted wide attention as novel antimicrobial agents due to their unique chemical and physical properties. In order to study the comparative effects on antibacterial and animal cytotoxicity, Staphylococcus aureus and NIH 3T3 fibroblasts were used, respectively. Both nanoparticles were synthesized via a novel matrix-mediated method using poly(ethylene) glycol. Formation of silver nanoparticles was confirmed by fluorescence and ultraviolet-visible spectroscopic techniques. The poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles were characterized by scanning electron microscope, transmission electron microscope, zeta potential, particle size analysis, Fourier-transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopy. The antimicrobial results indicate that both poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles inhibited S. aureus growth at the concentrations of 5 and 10?µg/mL at all time points without showing any significant cytotoxicity on NIH 3T3 fibroblasts. The particle size of both the poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles dominated in the range 10-15?nm, obtained by particle size analyzer. The poly(ethylene) glycol coating on the particles showed less aggregation of nanoparticles, as observed by scanning electron microscope and transmission electron microscope. The overall obtained results indicated that these two nanoparticles were stable and could be used to develop a magnetized antimicrobial scaffolds for biomedical applications. PMID:23959858

  5. LL37 peptide@silver nanoparticles: combining the best of the two worlds for skin infection control.

    PubMed

    Vignoni, Mariana; de Alwis Weerasekera, Hasitha; Simpson, Madeline J; Phopase, Jaywant; Mah, Thien-Fah; Griffith, May; Alarcon, Emilio I; Scaiano, Juan C

    2014-06-01

    Capping silver nanoparticles with LL37 peptide eradicates the antiproliferative effect of silver on primary skin cells, but retains the bactericidal properties of silver nanoparticles with activities comparable to silver nitrate or silver sulfadiazine. In addition, LL37 capped silver nanoparticles have anti-biofilm formation activity. PMID:24789474

  6. Gum arabic capped-silver nanoparticles inhibit biofilm formation by multi-drug resistant strains of Pseudomonas aeruginosa.

    PubMed

    Ansari, Mohammad Azam; Khan, Haris Manzoor; Khan, Aijaz Ahmed; Cameotra, Swaranjit Singh; Saquib, Quaiser; Musarrat, Javed

    2014-07-01

    Clinical isolates (n?=?55) of Pseudomonas aeruginosa were screened for the extended spectrum ?-lactamases and metallo-?-lactamases activities and biofilm forming capability. The aim of the study was to demonstrate the antibiofilm efficacy of gum arabic capped-silver nanoparticles (GA-AgNPs) against the multi-drug resistant (MDR) biofilm forming P. aeruginosa. The GA-AgNPs were characterized by UV-spectroscopy, X-ray diffraction, and high resolution-transmission electron microscopy analysis. The isolates were screened for their biofilm forming ability, using the Congo red agar, tube method and tissue culture plate assays. The biofilm forming ability was further validated and its inhibition by GA-AgNPs was demonstrated by performing the scanning electron microscopy (SEM) and confocal laser scanning microscopy. SEM analysis of GA-AgNPs treated bacteria revealed severely deformed and damaged cells. Double fluorescent staining with propidium iodide and concanavalin A-fluorescein isothiocyanate concurrently detected the bacterial cells and exopolysaccharides (EPS) matrix. The CLSM results exhibited the GA-AgNPs concentration dependent inhibition of bacterial growth and EPS matrix of the biofilm colonizers on the surface of plastic catheters. Treatment of catheters with GA-AgNPs at 50?µg?ml(-1) has resulted in 95% inhibition of bacterial colonization. This study elucidated the significance of GA-AgNPs, as the next generation antimicrobials, in protection against the biofilm mediated infections caused by MDR P. aeruginosa. It is suggested that application of GA-AgNPs, as a surface coating material for dispensing antibacterial attributes to surgical implants and implements, could be a viable approach for controlling MDR pathogens after adequate validations in clinical settings. PMID:24403133

  7. Synthesis of Silver Nanoparticles

    NSDL National Science Digital Library

    Johnson, Chris

    This series of videos, presented by the Materials Research Science and Engineering Center at the University of Wisconsin-Madison, deals with the synthesis of silver nanoparticles. The experiment allows students to view the formation of silver nanoparticles that can be detected by the reflection of a laser beam. Silver nanoparticles are used in the creation of yellow stained glass in churches around the country, an interesting, but little known fact. This is a fairly inexpensive activity as it involves stock solutions, and equipment present in any science laboratory. Overall, students will enjoy this basic, but still challenging, experiment.

  8. Effects from filtration, capping agents, and presence/absence of food on the toxicity of silver nanoparticles to Daphnia magna.

    PubMed

    Allen, H Joel; Impellitteri, Christopher A; Macke, Dana A; Heckman, J Lee; Poynton, Helen C; Lazorchak, James M; Govindaswamy, Shekar; Roose, Deborah L; Nadagouda, Mallikarjuna N

    2010-12-01

    Relatively little is known about the behavior and toxicity of nanoparticles in the environment. Objectives of work presented here include establishing the toxicity of a variety of silver nanoparticles (AgNPs) to Daphnia magna neonates, assessing the applicability of a commonly used bioassay for testing AgNPs, and determining the advantages and disadvantages of multiple characterization techniques for AgNPs in simple aquatic systems. Daphnia magna were exposed to a silver nitrate solution and AgNPs suspensions including commercially available AgNPs (uncoated and coated), and laboratory-synthesized AgNPs (coated with coffee or citrate). The nanoparticle suspensions were analyzed for silver concentration (microwave acid digestions), size (dynamic light scattering and electron microscopy), shape (electron microscopy), surface charge (zeta potentiometer), and chemical speciation (X-ray absorption spectroscopy, X-ray diffraction). Toxicities of filtered (100 nm) versus unfiltered suspensions were compared. Additionally, effects from addition of food were examined. Stock suspensions were prepared by adding AgNPs to moderately hard reconstituted water, which were then diluted and used straight or after filtration with 100-nm filters. All nanoparticle exposure suspensions, at every time interval, were digested via microwave digester and analyzed by inductively coupled argon plasma-optical emission spectroscopy or graphite furnace-atomic absorption spectroscopy. Dose-response curves were generated and median lethal concentration (LC50) values calculated. The LC50 values for the unfiltered particles were (in µg/L): 1.1 ± 0.1-AgNO(3) ; 1.0 ± 0.1-coffee coated; 1.1 ± 0.2-citrate coated; 16.7 ± 2.4 Sigma Aldrich Ag-nanoparticles (SA) uncoated; 31.5 ± 8.1 SA coated. LC50 values for the filtered particles were (in µg/L): 0.7 ± 0.1-AgNO(3) ; 1.4 ± 0.1-SA uncoated; 4.4 ± 1.4-SA coated. The LC50 resulting from the addition of food was 176.4 ± 25.5-SA coated. Recommendations presented in this study include AgNP handling methods, effects from sample preparation, and advantages/disadvantages of different nanoparticle characterization techniques. PMID:20890913

  9. Novel switchable sensor for phosphate based on the distance-dependant fluorescence coupling of cysteine-capped cadmium sulfide quantum dots and silver nanoparticles.

    PubMed

    Wang, Guang-Li; Jiao, Huan-Jun; Zhu, Xiao-Ying; Dong, Yu-Ming; Li, Zai-Jun

    2013-04-01

    A novel switchable sensor was developed for the determination of phosphate based on Ce(3+) induced aggregation and phosphate triggered disaggregation of cysteine (Cys)-capped CdS quantum dots (QDs) and silver nanoparticles (AgNPs). The rare earth metal Ce(3+) could aggregate a mixture of QDs and AgNPs, which induced electron or energy transfer between CdS QDs and AgNPs and serious fluorescence quenching. However, phosphate dissociated the formed aggregation of CdS QDs and AgNPs, restoring the enhanced fluorescence of Cys-capped CdS triggered by AgNPs. Although, CdS QDs alone could also be used to detect phosphate through the aggregation-disaggregation mechanism adjusted by Ce(3+) and phosphate. It was found that the distance-dependent interaction between AgNPs and CdS QDs driven by Ce(3+) and phosphate could lead to enhanced quenching or enhancement of the fluorescence of Cys-capped CdS to form a more sensitive detection system for phosphate. The developed method was applied in the detection of phosphate in real water samples with acceptable and satisfactory results. PMID:23435242

  10. Green synthesis of silver nanoparticles using Macrotyloma uniflorum.

    PubMed

    Vidhu, V K; Aromal, S Aswathy; Philip, Daizy

    2011-12-01

    Green synthesis of noble metal nanoparticles is a vast developing area of research. In this paper we report the green synthesis of silver nanoparticles using aqueous seed extract of Macrotyloma uniflorum. The effect of experimental parameters such as amount of extract, temperature and pH on the formation of silver nanoparticles was studied. The as prepared samples are characterized using XRD, TEM, UV-Visible and FTIR techniques. The formation of silver nanoparticles is evidenced by the appearance of signatory brown colour of the solution and UV-vis spectra. The XRD analysis shows that the silver nanoparticles are of face centered cubic structure. Well-dispersed silver nanoparticles with anisotropic morphology having size ?12 nm are seen in TEM images. FTIR spectrum indicates the presence of different functional groups in capping the nanoparticles. The possible mechanism leading to the formation of silver nanoparticles is suggested. PMID:21920808

  11. Facile synthesis of anisotropic silver nanoparticles and their surface-enhanced Raman scattering properties

    NASA Astrophysics Data System (ADS)

    Zhang, Danhui; Yang, Houbo

    2014-02-01

    In this work, polyvinylpyrrolidone(PVP)-capped silver nanoparticles were synthesized using ethylene glycol as solvent and reducing agent through a simple, one-pot solvothermal method at 160 °C. UV-vis spectroscopy, TEM and Raman spectra are used to characterize the PVP-capped silver nanoparticles. The results show that the formed silver nanoparticles are anisotropy with different size and morphology such as triangle, hexagon and pentagon. Moreover, the formation process of silver nanoparticles was discussed in detail. Furthermore, the formed silver nanoparticles displayed high surface-enhanced Raman scattering effects.

  12. Silver Nanoparticles in Dental Biomaterials

    PubMed Central

    Corrêa, Juliana Mattos; Mori, Matsuyoshi; Sanches, Heloísa Lajas; da Cruz, Adriana Dibo; Poiate, Isis Andréa Venturini Pola

    2015-01-01

    Silver has been used in medicine for centuries because of its antimicrobial properties. More recently, silver nanoparticles have been synthesized and incorporated into several biomaterials, since their small size provides great antimicrobial effect, at low filler level. Hence, these nanoparticles have been applied in dentistry, in order to prevent or reduce biofilm formation over dental materials surfaces. This review aims to discuss the current progress in this field, highlighting aspects regarding silver nanoparticles incorporation, such as antimicrobial potential, mechanical properties, cytotoxicity, and long-term effectiveness. We also emphasize the need for more studies to determine the optimal concentration of silver nanoparticle and its release over time. PMID:25667594

  13. Antimicrobial Properties of Silver Nanoparticles

    NSDL National Science Digital Library

    Kouadio, Carrie

    This module provides students the opportunity to "explore silver nanoparticles and their effectiveness against bacterial growth in hands-on laboratory activities." Students first make silver nanoparticles and then use them in an experiment they design. This lesson will require two or more class periods and is aimed at secondary students.The document is available to download in PDF file format.

  14. Shaped gold and silver nanoparticles

    Microsoft Academic Search

    Yugang Sun; Changhua An

    2011-01-01

    Advance in the synthesis of shaped nanoparticles made of gold and silver is reviewed in this article. This review starts with\\u000a a new angle by analyzing the relationship between the geometrical symmetry of a nanoparticle shape and its internal crystalline\\u000a structures. According to the relationship, the nanoparticles with well-defined shapes are classified into three categories:\\u000a nanoparticles with single crystallinity, nanoparticles

  15. Gold nanoparticles capped by peptides

    Microsoft Academic Search

    Francesca Porta; Giovanna Speranza; Željka Krpeti?; Vladimiro Dal Santo; Pierangelo Francescato; Giorgio Scarì

    2007-01-01

    Two dipeptides (GK and GC) and two 15-aminoacid peptides (GK15 and GC15) were used as capping agents in the preparation of monolayer-protected gold nanoparticles (MPCs). They were characterized by TEM microscopy, UV–vis, NMR and IR spectroscopy.

  16. Antimicrobial effects of silver nanoparticles

    Microsoft Academic Search

    Jun Sung Kim; Eunye Kuk; Kyeong Nam Yu; Jong-Ho Kim; Sung Jin Park; Hu Jang Lee; So Hyun Kim; Young Kyung Park; Yong Ho Park; Cheol-Yong Hwang; Yong-Kwon Kim; Yoon-Sik Lee; Dae Hong Jeong; Myung-Haing Cho

    2007-01-01

    The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanoparticles on microorganisms and antimicrobial mechanism have not been revealed clearly. Stable Ag nanoparticles were prepared and their shape and size distribution characterized by particle characterizer and transmission electron microscopic study. The antimicrobial activity of Ag nanoparticles was investigated against yeast, Escherichia coli,

  17. Phase Transfer Properties of Silver Nanoparticles

    Microsoft Academic Search

    Michiel Dokter

    2005-01-01

    Silver nanoparticles are synthesized by reduction of silver nitrate in a toluene solution of tetra-n-octyl ammonium bromide (TAB) and dodecanethiol (DDT). The nanoparticles consist of a silver core with DDT chemically bound at the particle surface. TAB remains associated with the particles and provides them extra stability. These passivated silver nanoparticles are dissolved in dry chloroform and various phase transfer

  18. Subchronic oral toxicity of silver nanoparticles

    Microsoft Academic Search

    Yong Soon Kim; Moon Yong Song; Jung Duck Park; Kyung Seuk Song; Hyeon Ryol Ryu; Yong Hyun Chung; Hee Kyung Chang; Ji Hyun Lee; Kyung Hui Oh; Bruce J Kelman; In Koo Hwang; Il Je Yu

    2010-01-01

    BACKGROUND: The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, consumer, medicinal, pesticide, and home products; however, silver nanoparticles remain a controversial area of research with respect to their toxicity in biological and ecological systems. RESULTS: This study tested the oral toxicity of silver nanoparticles (56 nm) over a period of 13 weeks (90

  19. The effect of natural water conditions on the anti-bacterial performance and stability of silver nanoparticles capped with different polymers.

    PubMed

    Zhang, Hongyin; Smith, James A; Oyanedel-Craver, Vinka

    2012-03-01

    This study evaluated the effect of natural water composition onto the bactericidal and physicochemical properties of silver nanoparticles (AgNPs) stabilized with three different polymeric compounds. All the nanoparticles behaved similarly in the water conditions tested. Compared to solutions with low organic matter content and monovalent ions, lower disinfection performances of AgNPs suspensions were obtained in the following order seawater ? high organic matter content water ? high divalent cations content synthetic water. Suspension of AgNPs in seawater and water with divalent cations (Ca(2+) and Mg(2+)) formed larger AgNPs aggregates (less than 1400 nm) compared to other solutions tested (up to approximately 38 nm). The critical coagulation concentration (CCC) of AgNPs was determined to quantitatively evaluate the stability of the nanoparticle suspension in different water conditions. When the concentration of dissolved organic matter was increased from 0 mg/L to 5 mg/L, the CCC increased by a factor in the range of 2.19 ± 0.25 for all AgNPs in divalent solutions, but a smaller increase occurred, in the range of 1.54 ± 0.21 fold, when monovalent solutions were used. The concentration of ionic silver released indicated that the dissolved Ag(+) (3.6-48.2 ppb) was less than 0.5% of the total mass of Ag(0) added. At all the conditions tested, the concentration of silver ions in solution had a negligible contribution to the overall anti-bacterial performance of AgNPs. This study demonstrated that the anti-bacterial performance of AgNPs at selected natural water conditions decreases in the presence of dissolved natural organic matter or divalent ions, such as humic acid and calcium carbonate. These results may be helpful in understanding the toxicity of AgNP in various natural water conditions and in explaining the risk associated with discharging AgNP in natural aquatic systems. PMID:22169660

  20. Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms

    EPA Science Inventory

    The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) capped silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) and titanium dioxide (TiO2) NPs in marine organisms via marine sediment exposure were investigated. Results from 7-d sedimen...

  1. Synthesis, characterization and catalytic activity of silver nanoparticles using Tribulus terrestris leaf extract.

    PubMed

    Ashokkumar, S; Ravi, S; Kathiravan, V; Velmurugan, S

    2014-01-01

    Biomediated silver nanoparticles were synthesized with the aid of an eco-friendly biomaterial, namely, aqueous Tribulus terrestris extract. Silver nanoparticles were synthesized using a rapid, single step, and completely green biosynthetic method employing aqueous T. terrestris leaf extracts as both the reducing and capping agent. Silver ions were rapidly reduced by aqueous T. terrestris leaf extracts, leading to the formation of highly crystalline silver nanoparticles. An attempt has been made and formation of the silver nanoparticles was verified by surface plasmon spectra using an UV-vis (Ultra violet), spectrophotometer. Morphology and crystalline structure of the prepared silver nanoparticles were characterized by TEM (Transmission Electron Microscope) and XRD (X-ray Diffraction), techniques, respectively. FT-IR (Fourier Transform Infrared), analysis suggests that the obtained silver nanoparticles might be stabilized through the interactions of carboxylic groups, carbonyl groups and the flavonoids present in the T. terrestris extract. PMID:24231743

  2. Evaluation of green synthesized silver nanoparticles against parasites

    Microsoft Academic Search

    Sampath Marimuthu; Abdul Abdul Rahuman; Govindasamy Rajakumar; Thirunavukkarasu Santhoshkumar; Arivarasan Vishnu Kirthi; Chidambaram Jayaseelan; Asokan Bagavan; Abdul Abduz Zahir; Gandhi Elango; Chinnaperumal Kamaraj

    2011-01-01

    Green nanoparticle synthesis has been achieved using environmentally acceptable plant extract and eco-friendly reducing and\\u000a capping agents. The present study was based on assessments of the antiparasitic activities to determine the efficacies of\\u000a synthesized silver nanoparticles (AgNPs) using aqueous leaf extract of Mimosa pudica Gaertn (Mimosaceae) against the larvae of malaria vector, Anopheles subpictus Grassi, filariasis vector Culex quinquefasciatus Say

  3. LL37 peptide@silver nanoparticles: combining the best of the two worlds for skin infection control

    NASA Astrophysics Data System (ADS)

    Vignoni, Mariana; de Alwis Weerasekera, Hasitha; Simpson, Madeline J.; Phopase, Jaywant; Mah, Thien-Fah; Griffith, May; Alarcon, Emilio I.; Scaiano, Juan C.

    2014-05-01

    Capping silver nanoparticles with LL37 peptide eradicates the antiproliferative effect of silver on primary skin cells, but retains the bactericidal properties of silver nanoparticles with activities comparable to silver nitrate or silver sulfadiazine. In addition, LL37 capped silver nanoparticles have anti-biofilm formation activity.Capping silver nanoparticles with LL37 peptide eradicates the antiproliferative effect of silver on primary skin cells, but retains the bactericidal properties of silver nanoparticles with activities comparable to silver nitrate or silver sulfadiazine. In addition, LL37 capped silver nanoparticles have anti-biofilm formation activity. Electronic supplementary information (ESI) available: Changes on AgNP-SPB absorption; changes on AgNP-SPB as A/A0 measured in LB or DMEM media; number of survival colonies in the presence of LL37; human skin fibroblasts cell toxicity in the presence of different silver sources measured using MTS assay; effect of LL37@AgNP on the proliferation profile of human skin fibroblasts; effect of AgSD and AgNO3 on the proliferation profile of human skin fibroblasts in the presence of LL37 peptide; representative flow cytometry profiles for human skin fibroblasts stained with Alexa Fluor®488 annexin V/Dead cell apoptosis kit. See DOI: 10.1039/c4nr01284d

  4. Silver Nanoparticles Part 2: BDo Silver Nanoparticles Inhibit Bacterial Growth?

    NSDL National Science Digital Library

    The NACK Center is an organization committed to supporting two â??year degree programs in micro and nanotechnology. The center offers online educational material for curriculum enhancement in this subject field. One of these resources is a lab documentation focusing on the topic of silver nanoparticles. The lab "may be used with a middle school through high school biology class.â? The lesson includes objectives, sample solution preparations, and sample data and calculations. Overall, the objectives of this lesson are to practice aseptic techniques to inoculate/grow bacteria and describe the impact of silver nanoparticles on bacterial growth. The site requires a free log-in for access to the material.

  5. Anodic stripping voltammetry of silver nanoparticles: aggregation leads to incomplete stripping.

    PubMed

    Cloake, Samantha J; Toh, Her Shuang; Lee, Patricia T; Salter, Chris; Johnston, Colin; Compton, Richard G

    2015-02-01

    The influence of nanoparticle aggregation on anodic stripping voltammetry is reported. Dopamine-capped silver nanoparticles were chosen as a model system, and melamine was used to induce aggregation in the nanoparticles. Through the anodic stripping of the silver nanoparticles that were aggregated to different extents, it was found that the peak area of the oxidative signal corresponding to the stripping of silver to silver(I) ions decreases with increasing aggregation. Aggregation causes incomplete stripping of the silver nanoparticles. Two possible mechanisms of 'partial oxidation' and 'inactivation' of the nanoparticles are proposed to account for this finding. Aggregation effects must be considered when anodic stripping voltammetry is used for nanoparticle detection and quantification. Hence, drop casting, which is known to lead to aggregation, is not encouraged for preparing electrodes for analytical purposes. PMID:25861566

  6. Negligible Particle-Specific Antibacterial Activity of Silver Nanoparticles

    E-print Network

    Alvarez, Pedro J.

    Negligible Particle-Specific Antibacterial Activity of Silver Nanoparticles Zong-ming Xiu, Qing. KEYWORDS: Silver nanoparticles, toxicity, metallic nanoparticle, silver ion, E. coli As a broad of silver ions from the crystalline core of silver nanoparticles contribute to the toxicity

  7. The effect of temperature on antibacterial activity of biosynthesized silver nanoparticles.

    PubMed

    Pourali, Parastoo; Baserisalehi, Majid; Afsharnezhad, Sima; Behravan, Javad; Ganjali, Rashin; Bahador, Nima; Arabzadeh, Sepideh

    2013-02-01

    The purpose of this study was the evaluation of two different temperatures on antibacterial activity of the biosynthesized silver nanoparticles. 38 silver nanoparticles-producing bacteria were isolated from soil and identified. Biosynthesis of silver nanoparticles by these bacteria was verified through visible light spectrophotometry. Two strains were relatively active for production of silver nanoparticles. These strains were subjected for molecular identification and recognized as Bacillus sp. and Acinetobacter schindleri. In the present study, the effect of temperatures was evaluated on structure and antimicrobial properties of the silver nanoparrticles by transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis and antimicrobial Agar well diffusion methods. The silver nanoparticles showed antibacterial activity against all the pathogenic bacteria; however, this property was lost after treatment of the silver nanoparticles by high temperatures (100 and 300 °C). TEM images showed that the average sizes of heated silver nanoparticles were >100 nm. However, these were <100 nm for non-heated silver nanoparticles. Although, XRD patterns showed the crystalline structure of heated silver nanoparticles, their antibacterial activities were less. This was possible because of the sizes and accordingly less penetration of the particles into the bacterial cells. In addition, elimination of the capping agents by heat might be considered another reason. PMID:23324852

  8. Biosynthesis, characterization and cytotoxic effect of plant mediated silver nanoparticles using Morinda citrifolia root extract.

    PubMed

    Suman, T Y; Radhika Rajasree, S R; Kanchana, A; Elizabeth, S Beena

    2013-06-01

    Silver has been used since time to control bodily infection, prevent food spoilage and heal wounds by preventing infection. The present study aims at an environmental friendly method of synthesizing silver nanoparticles, from the root of Morinda citrifolia; without involving chemical agents associated with environmental toxicity. The obtained nanoparticles were characterized by UV-vis absorption spectroscopy with an intense surface plasmon resonance band at 413 nm clearly reveals the formation of silver nanoparticles. Fourier transmission infra red spectroscopy (FTIR) showed nanopartilces were capped with plant compounds. Field emission-scanning electron microscopy (FE-SEM) and Transmission electron microscopy (TEM) showed that the spherical nature of the silver nanoparticles with a size of 30-55 nm. The X-ray diffraction spectrum XRD pattern clearly indicates that the silver nanoparticles formed in the present synthesis were crystalline in nature. In addition these biologically synthesized nanoparticles were also proved to exhibit excellent cytotoxic effect on HeLa cell. PMID:23434694

  9. Amorphous silicon coatings with silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Tuleushev, Yu. Zh.; Volodin, V. N.; Zhakanbaev, E. A.; Zdorovets, M. V.

    2013-11-01

    We describe a plasma-ion sputtering technology for obtaining amorphous silicon coatings containing dispersed silver nanoparticles with average dimensions of 20-30 nm. Results of X-ray diffraction and electron-microscopic investigations of these coatings are presented, and a possible mechanism of silver nano-particle formation from 2- to 3-nm-sized nanoclusters is considered.

  10. Conductivity of silver paste prepared from nanoparticles

    Microsoft Academic Search

    Dongseok Seo; Jongkook Lee

    2008-01-01

    Conductivity of silver pastes using nanoparticles was investigated with sintering temperatures. Nano-sized silver particles with 50–100nm in size were prepared by chemical reduction method. Silver pastes composed of nanoparticles (80wt%), Pb-free frit (1.0wt%) and organic vehicle (19wt%) were screen printed on alumina substrates and sintered at temperatures ranging from 250 to 450°C. As increasing the sintering temperatures, densification and grain

  11. Photocatalytic activity of biogenic silver nanoparticles synthesized using yeast (Saccharomyces cerevisiae) extract

    NASA Astrophysics Data System (ADS)

    Roy, Kaushik; Sarkar, C. K.; Ghosh, C. K.

    2014-12-01

    Synthesis of metallic and semiconductor nanoparticles through physical and chemical route is quiet common but biological synthesis procedures are gaining momentum due to their simplicity, cost-effectivity and eco-friendliness. Here, we report green synthesis of silver nanoparticles from aqueous solution of silver salts using yeast (Saccharomyces cerevisiae) extract. The nanoparticles formation was gradually investigated by UV-Vis spectrometer. X-ray diffraction analysis was done to identify different phases of biosynthesized Ag nanoparticles. Transmission electron microscopy was performed to study the particle size and morphology of silver nanoparticles. Fourier transform infrared spectroscopy of the nanoparticles was performed to study the role of biomolecules capped on the surface of Ag nanoparticles during interaction. Photocatalytic activity of these biosynthesized nanoparticles was studied using an organic dye, methylene blue under solar irradiation and these nanoparticles showed efficacy in degrading the dye within a few hours of exposure.

  12. Glutathione promoted expeditious green synthesis of silver nanoparticles in water using microwaves

    EPA Science Inventory

    Silver nanoparticles with size range 5-10 nm has been synthesized under microwave irradiation conditions using gluathione, an absolutely benign antioxidant that serves as the reducing as well as capping agent in aqueous medium. This rapid protocol yields the nanoparticles within ...

  13. Anti-bacterial Studies of Silver Nanoparticles

    E-print Network

    T. Theivasanthi; M. Alagar

    2011-01-01

    We discuss about the antibacterial activities of Silver nanoparticles and compare them on both Gram negative and Gram positive bacteria in this investigation. The activities of Silver nanoparticles synthesized by electrolysis method are more in Gram (-) than Gram (+) bacteria. First time, we increase its antibacterial activities by using electrical power while on electrolysis synthesis and it is confirmed from its more antibacterial activities (For Escherichia coli bacteria). We investigate the changes of inner unit cell Lattice constant of Silver nanoparticles prepared in two different methods and its effects on antibacterial activities. We note that slight change of the lattice constant results in the enhancement of its antibacterial activities.

  14. Drastic nickel ion removal from aqueous solution by curcumin-capped Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Bettini, S.; Pagano, R.; Valli, L.; Giancane, G.

    2014-08-01

    A completely green synthesis protocol has been adopted to obtain silver nanoaggregates capped by the natural compound (1E, 6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-diene), also known as curcumin. The synthesis has been monitored by infrared, Raman, visible and fluorescence spectroscopies. Characterization confirms that curcumin reduces and caps the nanoparticles, and such a procedure allows its solubility in water and drastically increases curcumin stability. Silver nanoparticles (AgNPs)/curcumin complex has been dispersed in a water solution containing a known nickel ion concentration. After three days, a grey precipitate is observed and nickel concentration in the solution is reduced by about 70%.A completely green synthesis protocol has been adopted to obtain silver nanoaggregates capped by the natural compound (1E, 6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-diene), also known as curcumin. The synthesis has been monitored by infrared, Raman, visible and fluorescence spectroscopies. Characterization confirms that curcumin reduces and caps the nanoparticles, and such a procedure allows its solubility in water and drastically increases curcumin stability. Silver nanoparticles (AgNPs)/curcumin complex has been dispersed in a water solution containing a known nickel ion concentration. After three days, a grey precipitate is observed and nickel concentration in the solution is reduced by about 70%. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr02583k

  15. Evaluation of antioxidant, antibacterial and cytotoxic effects of green synthesized silver nanoparticles by Piper longum fruit.

    PubMed

    Reddy, N Jayachandra; Nagoor Vali, D; Rani, M; Rani, S Sudha

    2014-01-01

    Silver nanoparticles synthesized through bio-green method has been reported to have biomedical applications to control pathogenic microbes as it is cost effective compared to commonly used physical and chemical methods. In present study, silver nanoparticles were synthesized using aqueous Piper longum fruit extract (PLFE) and confirmed by UV-visible spectroscopy. The nanoparticles were spherical in shape with an average particle size of 46nm as determined by scanning electronic microscopy (SEM) and dynamic light scattering (DLS) particle size analyzer respectively. FT-IR spectrum revealed the capping of the phytoconstituents, probably polyphenols from P. longum fruit extract and stabilizing the nanoparticles. Further the ferric ion reducing test, confirmed that the capping agents were condensed tannins. The aqueous P. longum fruit extract (PLFE) and the green synthesized silver nanoparticles (PLAgNPs) showed powerful antioxidant properties in in vitro antioxidant assays. The results from the antimicrobial assays suggested that green synthesized silver nanoparticles (PLAgNPs) were more potent against pathogenic bacteria than the P. longum fruit extract (PLFE) alone. The nanoparticles also showed potent cytotoxic effect against MCF-7 breast cancer cell lines with an IC 50 value of 67?g/ml/24h by the MTT assay. These results support the advantages of using bio-green method for synthesizing silver nanoparticles with antioxidant, antimicrobial and cytotoxic activities those are simple and cost effective as well. PMID:24268240

  16. Green synthesis of silver nanoparticles from aqueous Aegle marmelos leaf extract

    SciTech Connect

    Jagajjanani Rao, K. [Department of Chemical Engineering, National Institute of Technology, Rourkela 769 008, Orissa (India)] [Department of Chemical Engineering, National Institute of Technology, Rourkela 769 008, Orissa (India); Paria, Santanu, E-mail: santanuparia@yahoo.com [Department of Chemical Engineering, National Institute of Technology, Rourkela 769 008, Orissa (India)] [Department of Chemical Engineering, National Institute of Technology, Rourkela 769 008, Orissa (India)

    2013-02-15

    Graphical abstract: Silver nanoparticles capped with polyphenols present in Aegle marmelos leaf extract. Display Omitted Highlights: ? Silver nanoparticles are synthesized using Aegle marmelos leaf extract in aqueous media. ? Reduction reaction is fast and occurs at room temperature. ? The presence of polyphenols acts as in situ capping agent. -- Abstract: Synthesis of nanoparticles by green route is an emerging technique drawing more attention recently because of several advantages over the convention chemical routes. The present study reports one-pot synthesis and in situ stabilization of silver nanoparticles using Aegle marmelos leaf extract. Nanoparticles of almost uniform spherical size (?60 nm) were synthesized within ?25 min reaction time at room temperature. The size of particles depends on the ratio of AgNO{sub 3} and leaf extract. The crystallinity, size, and shape of the nanoparticles were characterized by X-ray diffraction, dynamic light scattering, and scanning electron microscopy respectively. The size stability was attained by the capping effect of polyphenolic tannin compound, procatacheuate in the extract. The capped polyphenols can be removed from the particle surface by simple NaOH/methanol wash. The involvement of phenolic compounds in metal ion reduction and capping were supported by UV–visible spectroscopy, infrared spectroscopy, high performance liquid chromatography, and zeta potential measurements.

  17. Silver nanoparticle applications and human health

    Microsoft Academic Search

    Maqusood Ahamed; Mohamad S. AlSalhi; M. K. J. Siddiqui

    2010-01-01

    Nanotechnology is rapidly growing with nanoparticles produced and utilized in a wide range of commercial products throughout the world. For example, silver nanoparticles (Ag NP) are used in electronics, bio-sensing, clothing, food industry, paints, sunscreens, cosmetics and medical devices. These broad applications, however, increase human exposure and thus the potential risk related to their short- and long-term toxicity. A large

  18. Antimicrobial activity of spherical silver nanoparticles prepared using a biocompatible macromolecular capping agent: evidence for induction of a greatly prolonged bacterial lag phase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have evaluated the antimicrobial properties of Ag-based nanoparticles (Np) using two solid platform-based bioassays and found that 10-20 uL of 0.3-3 uM keratin-based Nps (depending on the starting bacteria concentration = CI) completely inhibited the growth of an equivalent volume of ca. 1,000 to...

  19. Photochromic silver nanoparticles fabricated by sputter deposition

    SciTech Connect

    Okumu, J.; Dahmen, C.; Sprafke, A.N.; Luysberg, M.; Plessen, G. von; Wuttig, M. [Department of Physics, Kenyatta University, P.O. Box 43844, Nairobi (Kenya); I. Physikalisches Institut (IA), Lehrstuhl fuer Physik neuer Materialien, Rheinisch-Westfaelische Technische Hochschule (RWTH) Aachen, 52056 Aachen (Germany); Institut fuer Festkoerperforschung (IFF)/ Forschungszentrum Juelich, 52428 Juelich (Germany); I. Physikalisches Institut (IA), Lehrstuhl fuer Physik neuer Materialien, Rheinisch-Westfaelische Technische Hochschule (RWTH) Aachen, 52056 Aachen (Germany)

    2005-05-01

    In this study a simple route to preparing photochromic silver nanoparticles in a TiO{sub 2} matrix is presented, which is based upon sputtering and subsequent annealing. The formation of silver nanoparticles with sizes of some tens of nanometers is confirmed by x-ray diffraction and transmission electron microscopy. The inhomogeneously broadened particle-plasmon resonance of the nanoparticle ensemble leads to a broad optical-absorption band, whose spectral profile can be tuned by varying the silver load and the annealing temperature. Multicolor photochromic behavior of this Ag-TiO{sub 2} system upon irradiation with laser light is demonstrated and discussed in terms of a particle-plasmon-assisted electron transfer from the silver nanoparticles to TiO{sub 2} and subsequent trapping by adsorbed molecular oxygen. The electron depletion in the nanoparticles reduces the light absorption at the wavelength of irradiation. A gradual recovery of the absorption band is observed after irradiation, which is explained with a slow thermal release of electrons from the oxygen trapping centers and subsequent capture into the nanoparticles. The recovery can be accelerated by ultraviolet irradiation; the explanation for this observation is that electrons photoexcited in the TiO{sub 2} are captured into the nanoparticles and restore the absorption band.

  20. Glucoxylan-mediated green synthesis of gold and silver nanoparticles and their phyto-toxicity study.

    PubMed

    Iram, Fozia; Iqbal, Mohammad S; Athar, Muhammad M; Saeed, Muhammad Z; Yasmeen, Abida; Ahmad, Riaz

    2014-04-15

    A green synthesis of gold and silver nanoparticles having exceptional high stability is reported. The synthesis involves the use of glucoxylans isolated from seeds of Mimosa pudica and excludes the use of conventional reducing and capping agents. The average particle sizes were 40 and 6 nm for gold and silver, respectively. The size of gold particles obtained in this work is suitable for drug delivery as they are non-cytotoxic. In phyto-toxicity tests the gold and silver nanoparticles did not show any significant effect on germination of radish seeds, whereas in radish seedling root growth assay the two particles behaved differently. The silver nanoparticles exhibited a concentration-dependent stimulatory effect on root length, whereas the gold nanoparticles had no significant effect in this test. The likely mechanism of these effects is discussed. PMID:24607156

  1. Application of statistical experimental design for optimization of silver nanoparticles biosynthesis by a nanofactory Streptomyces viridochromogenes.

    PubMed

    El-Naggar, Noura El-Ahmady; Abdelwahed, Nayera A M

    2014-01-01

    Central composite design was chosen to determine the combined effects of four process variables (AgNO3 concentration, incubation period, pH level and inoculum size) on the extracellular biosynthesis of silver nanoparticles (AgNPs) by Streptomyces viridochromogenes. Statistical analysis of the results showed that incubation period, initial pH level and inoculum size had significant effects (P<0.05) on the biosynthesis of silver nanoparticles at their individual level. The maximum biosynthesis of silver nanoparticles was achieved at a concentration of 0.5% (v/v) of 1 mM AgNO3, incubation period of 96 h, initial pH of 9 and inoculum size of 2% (v/v). After optimization, the biosynthesis of silver nanoparticles was improved by approximately 5-fold as compared to that of the unoptimized conditions. The synthetic process of silver nanoparticle generation using the reduction of aqueous Ag+ ion by the culture supernatants of S. viridochromogenes was quite fast, and silver nanoparticles were formed immediately by the addition of AgNO3 solution (1 mM) to the cell-free supernatant. Initial characterization of silver nanoparticles was performed by visual observation of color change from yellow to intense brown color. UV-visible spectrophotometry for measuring surface plasmon resonance showed a single absorption peak at 400 nm, which confirmed the presence of silver nanoparticles. Fourier Transform Infrared Spectroscopy analysis provided evidence for proteins as possible reducing and capping agents for stabilizing the nanoparticles. Transmission Electron Microscopy revealed the extracellular formation of spherical silver nanoparticles in the size range of 2.15-7.27 nm. Compared to the cell-free supernatant, the biosynthesized AgNPs revealed superior antimicrobial activity against Gram-negative, Gram-positive bacterial strains and Candida albicans. PMID:24390838

  2. Cytotoxicity and genotoxicity of biogenic silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Lima, R.; Feitosa, L. O.; Ballottin, D.; Marcato, P. D.; Tasic, L.; Durán, N.

    2013-04-01

    Biogenic silver nanoparticles with 40.3 ± 3.5 nm size and negative surface charge (- 40 mV) were prepared with Fusarium oxysporum. The cytotoxicity of 3T3 cell and human lymphocyte were studied by a TaliTM image-based cytometer and the genotoxicity through Allium cepa and comet assay. The results of BioAg-w (washed) and BioAg-nw (unwashed) biogenic silver nanoparticles showed cytotoxicity exceeding 50 ?g/mL with no significant differences of response in 5 and 10 ?g/mL regarding viability. Results of genotoxicity at concentrations 5.0 and 10.0 ug/mL show some response, but at concentrations 0.5 and 1.0 ?g/mL the washed and unwashed silver nanoparticles did not present any effect. This in an important result since in tests with different bacteria species and strains, including resistant, MIC (minimal inhibitory concentration) had good answers at concentrations less than 1.9 ?g/mL. This work concludes that biogenic silver nanoparticles may be a promising option for antimicrobial use in the range where no cyto or genotoxic effect were observed. Furthermore, human cells were found to have a greater resistance to the toxic effects of silver nanoparticles in comparison with other cells.

  3. Mechanism of growth of colloidal silver nanoparticles stabilized by polyvinyl pyrrolidone in ?-irradiated silver nitrate solution

    Microsoft Academic Search

    Hyeon Suk Shin; Hyun Jung Yang; Seung Bin Kim; Mu Sang Lee

    2004-01-01

    Silver nanoparticles were prepared by using polyvinyl pyrrolidone (PVP) as a stabilizer and ?-irradiation. Transmission electron microscopy (TEM) results showed that both the amount and the molecular weight of PVP in the irradiated solution considerably affect the average size of the silver nanoparticles. The average size of the silver nanoparticles decreases with increasing the amount of PVP in the solution,

  4. Coupled plasmons induce broadband circular dichroism in patternable films of silver nanoparticles with chiral ligands.

    PubMed

    Vidal, Xavier; Kim, Won Jin; Baev, Alexander; Tokar, Valentyna; Jee, Hongsub; Swihart, Mark T; Prasad, Paras N

    2013-11-01

    This contribution reports the chiro-optic response of as-cast and photopatterned films of silver nanoparticles capped with photothermally-cleavable chiral ligands. We demonstrate broadband circular dichroism in these nanoparticle films, which is not present in dispersions of the nanoparticles capped with the chiral ligands. Long wavelength circular dichroism is derived from coupling of the plasmonic bands of neighbouring silver nanoparticles. Furthermore, the chiral response is preserved in the microstructured film after photopatterning using direct two-photon absorption in the plasmonic band of the silver nanoparticles. Thus, both the as-cast and photopatterned films show circular dichroism from the UV wavelength of intrinsic absorption of the ligand, through the plasmon resonances of both the isolated silver nanoparticles and the interacting nanoparticles, which extend to the near IR. Density functional theory (DFT) calculations of model electronic complexes of a chiral ligand and a small metallic cluster suggest that the new chiral bands at the plasmonic resonances are derived from new chiral hybrid electronic states of the metal nanoparticle-ligand complexes. PMID:24056891

  5. Biomimetic synthesis and patterning of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Naik, Rajesh R.; Stringer, Sarah J.; Agarwal, Gunjan; Jones, Sharon E.; Stone, Morley O.

    2002-11-01

    The creation of nanoscale materials for advanced structures has led to a growing interest in the area of biomineralization. Numerous microorganisms are capable of synthesizing inorganic-based structures. For example, diatoms use amorphous silica as a structural material, bacteria synthesize magnetite (Fe3O4) particles and form silver nanoparticles, and yeast cells synthesize cadmium sulphide nanoparticles. The process of biomineralization and assembly of nanostructured inorganic components into hierarchical structures has led to the development of a variety of approaches that mimic the recognition and nucleation capabilities found in biomolecules for inorganic material synthesis. In this report, we describe the in vitro biosynthesis of silver nanoparticles using silver-binding peptides identified from a combinatorial phage display peptide library.

  6. Fluorescence enhancement of Rhodamine B by monodispersed silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Suslov, A.; Lama, P. T.; Dorsinville, R.

    2015-06-01

    A strong enhancement in fluorescence of Rhodamine B dye in the vicinity of silver monodisperse nanoparticles is presented. The fluorescence of the dye increased as much as by 23 times in the presence of monodispersed silver nanoparticles. The fluorescence enhancement due to monodispersed silver nanoparticles was about 2-3 times larger than in the presence of polydispersed silver nanoparticles. The additional enhancement is explained in terms of emergence of uniform and large local electromagnetic field induced by surface plasmon resonance around an ensemble of monodispersed silver nanoparticles.

  7. Biosynthesis of silver nanoparticles from Premna serratifolia L. leaf and its anticancer activity in CCl4-induced hepato-cancerous Swiss albino mice

    NASA Astrophysics Data System (ADS)

    Arockia John Paul, J.; Karunai Selvi, B.; Karmegam, N.

    2015-01-01

    In this study, we report the biosynthesis of silver nanoparticles using the ethanolic leaf powder extract of Premna serratifolia L. and its anticancer activity in carbon tetra chloride (CCl4)-induced liver cancer in Swiss albino mice (Balb/c). The synthesized silver nanoparticles were characterized by SEM, FTIR and XRD analyses. The Debye-Scherrer equation was used to calculate particle size and the average size of silver nanoparticles synthesized from P. serratifolia leaf extract was 22.97 nm. The typical pattern revealed that the sample contained cubic structure of silver nanoparticles. FTIR analysis confirmed that the bioreduction of silver ions to silver nanoparticles is due to reduction by capping material of the plant extract. The silver nanoparticles of P. serratifolia leaf extract were effective in treating liver cancer in Swiss albino mice when compared with P. serratifolia leaf extract with isoleucine.

  8. Photocatalytic activity of biogenic silver nanoparticles synthesized using potato (Solanum tuberosum) infusion

    NASA Astrophysics Data System (ADS)

    Roy, Kaushik; Sarkar, C. K.; Ghosh, C. K.

    2015-07-01

    In this study, we have reported a fast and eco-benign procedure to synthesis silver nanoparticle at room temperature using potato (Solanum tuberosum) infusion along with the study of its photocatalytic activity on methyl orange dye. After addition of potato infusion to silver nitrate solution, the color of the mixture changed indicating formation of silver nanoparticles. Time dependent UV-Vis spectra were obtained to study the rate of nanoparticle formation with time. Purity and crystallinity of the biogenic silver nanoparticles were examined by X-ray diffraction (XRD). Average size and morphology of the nanoparticles were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Fourier transform infra-red spectroscopy (FTIR) was employed to detect functional bio-molecules responsible that contribute to the reduction and capping of biosynthesized Ag nanoparticles. Further, these synthesized nanoparticles were used to investigate their ability to degrade methyl orange dye under sunlight irradiation and the results showed effective photocatalytic property of these biogenic silver nanoparticles.

  9. Glass frits coated with silver nanoparticles for silicon solar cells

    NASA Astrophysics Data System (ADS)

    Li, Yingfen; Gan, Weiping; Zhou, Jian; Li, Biyuan

    2015-06-01

    Glass frits coated with silver nanoparticles were prepared by electroless plating. Gum Arabic (GA) was used as the activating agent of glass frits without the assistance of stannous chloride or palladium chloride. The silver-coated glass frits prepared with different GA dosages were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). The characterization results indicated that silver-coated glass frits had the structures of both glass and silver. Spherical silver nanoparticles were distributed on the glass frits evenly. The density and particle size of silver nanoparticles on the glass frits can be controlled by adjusting the GA dosage. The silver-coated glass frits were applied to silver pastes to act as both the densification promoter and silver crystallite formation aid in the silver electrodes. The prepared silver-coated glass frits can improve the photovoltaic performances of solar cells.

  10. Synthesis, characterization and biocompatibility of silver nanoparticles synthesized from Nigella sativa leaf extract in comparison with chemical silver nanoparticles.

    PubMed

    Amooaghaie, Rayhaneh; Saeri, Mohammad Reza; Azizi, Morteza

    2015-10-01

    Despite the development potential in the field of nanotechnology, there is a concern about possible effects of nanoparticles on the environment and human health. In this study, silver nanoparticles (AgNPs) were synthesized by 'green' and 'chemical' methods. In the wet-chemistry method, sodium borohydrate, sodium citrate and silver nitrate were used as raw materials. Leaf extract of Nigella sativa was used as reducing as well as capping agent to reduce silver nitrate in the green synthesis method. In addition, toxic responses of both synthesized AgNPs were monitored on bone-building stem cells of mice as well as seed germination and seedling growth of six different plants (Lolium, wheat, bean and common vetch, lettuce and canola). In both synthesis methods, the colorless reaction mixtures turned brown and UV-visible spectra confirmed the presence of silver nanoparticles. Scanning electron microscope (SEM) observations revealed the predominance of silver nanosized crystallites and fourier transform infra-red spectroscopy (FTIR) indicated the role of different functional groups in the synthetic process. MTT assay showed cell viability of bone-building stem cells of mice was further in the green AgNPs synthesized using black cumin extract than chemical AgNPs. IC50 (inhibitory concentrations) values for seed germination, root and shoot length for 6 plants in green AgNPs exposures were higher than the chemical AgNPs. These results suggest that cytotoxicity and phytotoxicity of the green synthesized AgNPs were significantly less than wet-chemistry synthesized ones. This study indicated an economical, simple and efficient ecofriendly technique using leaves of N. sativa for synthesis of AgNPs and confirmed that green AgNPs are safer than chemically-synthesized AgNPs. PMID:26122733

  11. Biogenic silver nanoparticles associated with silver chloride nanoparticles (Ag@AgCl) produced by laccase from Trametes versicolor.

    PubMed

    Durán, Nelson; Cuevas, Raphael; Cordi, Livia; Rubilar, Olga; Diez, Maria Cristina

    2014-01-01

    In the present study, semi-purified laccase from Trametes versicolor was applied for the synthesis of silver nanoparticles, and the properties of the produced nanoparticles were characterized. All of the analyses of the spectra indicated silver nanoparticle formation. A complete characterization of the silver nanoparticles showed that a complex of silver nanoparticles and silver ions was produced, with the majority of the particles having a Ag(2+) chemical structure. A hypothetical mechanistic scheme was proposed, suggesting that the main pathway that was used was the interaction of silver ions with the T1 site of laccase, producing silver nanoparticles with the concomitant inactivation of laccase activity and posterior complexing with silver ions. PMID:25485188

  12. Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

    SciTech Connect

    Paeng, Dongwoo; Grigoropoulos, Costas P., E-mail: cgrigoro@berkeley.edu [Department of Mechanical Engineering, University of California Berkeley, Berkeley, California 94720-1740 (United States); Lee, Daeho [Department of Mechanical Engineering, Gachon University, Seongnam-si, Gyeonggi-do 461-701 (Korea, Republic of)

    2014-08-18

    In-situ optical probing has been performed to analyze and compare the characteristic coalescence time scales of silver ion-doped polyvinylalcohol nanocomposite (Ag-PVA NC) and polyvinylpyrrolidone-capped silver nanoparticle (Ag-PVP NP) films subjected to continuous wave laser irradiation. The Ag-PVA NC yielded conductive metallic patterns by photothermal reduction of PVA, formation of nanoparticles from silver ions and their subsequent coalescence. On the other hand, Ag-PVP NP thin films produced conductive patterns through only coalescence of nanoparticles. Upon laser irradiation, Ag-PVA NC and Ag-PVP NP films exhibited different coalescence characteristics.

  13. Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

    NASA Astrophysics Data System (ADS)

    Paeng, Dongwoo; Lee, Daeho; Grigoropoulos, Costas P.

    2014-08-01

    In-situ optical probing has been performed to analyze and compare the characteristic coalescence time scales of silver ion-doped polyvinylalcohol nanocomposite (Ag-PVA NC) and polyvinylpyrrolidone-capped silver nanoparticle (Ag-PVP NP) films subjected to continuous wave laser irradiation. The Ag-PVA NC yielded conductive metallic patterns by photothermal reduction of PVA, formation of nanoparticles from silver ions and their subsequent coalescence. On the other hand, Ag-PVP NP thin films produced conductive patterns through only coalescence of nanoparticles. Upon laser irradiation, Ag-PVA NC and Ag-PVP NP films exhibited different coalescence characteristics.

  14. Interactions between silver nanoparticles and polyvinyl alcohol nanofibers

    SciTech Connect

    Chou, H. L. [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, 43, Section 4, Keelung Road, Taipei, 106, Taiwan. (China); Wu, C. M., E-mail: cmwu@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Section 4, Keelung Road, Taipei, 106, Taiwan. (China); Lin, F. D. [Department of Fiber and Composite Materials, Feng-Chia University, 40724, Taiwan. (China); Rick, J. [Department of Chemical Engineering, National Taiwan University of Science and Technology, 43, Section 4, Keelung Road, Taipei, 106, Taiwan. (China)

    2014-08-15

    The interaction of polyvinylalcohol (PVA) nanofibers with silver (Ag) nanoparticles (mean diameter 8nm) has been modeled using density functional theory (DFT) calculations. The physical adsorption of PVA through the hydroxyl group, to the Ag, and its corresponding molecular orientation was compared with experimental results obtained from surface-enhanced Raman scattering (SERS) studies of the same material. A good agreement was found between the computational model of the vibrational spectrum of the adsorbate and the experimentally observed SERS. In general, aliphatic capping molecules are used to passivate the surface of Ag{sub 55} nanocrystals (55 = atomic number of Ag). In this study, a DFT simulation was employed to show binding energies and electron contour map analyses of Ag{sub 55} with PVA. Here we show that the PVA interacts with the Ag nanoparticle's surface, through the OH group, thereby contributing significantly to the increase in SERS activity.

  15. Extracellular biosynthesis of silver nanoparticles using the fungus Fusarium semitectum

    SciTech Connect

    Basavaraja, S.; Balaji, S.D. [Department of Materials Science, Gulbarga University, Gulbarga 585106, Karnataka (India); Department of Chemistry, Gulbarga University, Gulbarga 585106, Karnataka (India); Lagashetty, Arunkumar [Appa Institute of Engineering and Technology, Gulbarga 585102, Karnataka (India); Rajasab, A.H. [Department of Botany, Gulbarga University, Gulbarga 585106, Karnataka (India); Venkataraman, A. [Department of Materials Science, Gulbarga University, Gulbarga 585106, Karnataka (India); Department of Chemistry, Gulbarga University, Gulbarga 585106, Karnataka (India)], E-mail: raman_chem@rediffmail.com

    2008-05-06

    Development of environmental friendly procedures for the synthesis of metal nanoparticles through biological processes is evolving into an important branch of nanobiotechnology. In this paper, we report on the use of fungus 'Fusarium semitectum' for the extracellular synthesis of silver nanoparticles from silver nitrate solution (i.e. through the reduction of Ag{sup +} to Ag{sup 0}). Highly stable and crystalline silver nanoparticles are produced in solution by treating the filtrate of the fungus F. semitectum with the aqueous silver nitrate solution. The formations of nanoparticles are understood from the UV-vis and X-ray diffraction studies. Transmission electron microscopy of the silver particles indicated that they ranged in size from 10 to 60 nm and are mostly spherical in shape. Interestingly the colloidal suspensions of silver nanoparticles are stable for many weeks. Possible medicinal applications of these silver nanoparticles are envisaged.

  16. Antibacterial Activity of Green Synthesized Silver Nanoparticles Using Vasaka (Justicia adhatoda L.) Leaf Extract.

    PubMed

    Bose, Debadin; Chatterjee, Someswar

    2015-06-01

    There is an increasing demand for silver nanoparticles due to its wide applicability in various area of biological science such as in field of antimicrobial and therapeutics, biosensing, drug delivery etc. To use in bioprocess the silver nanoparticles should be biocompatible and free from toxic chemicals. In the present study we report a cost effective and environment friendly route for green synthesis of silver nanoparticles using Vasaka (Justicia adhatoda L.) leaf extract as reducing as well as capping agent. This plant has been opted for the present study for its known medicinal properties and it is easily available. The biosynthesized silver nanoparticles are characterized by UV-Vis spectroscopy and TEM analysis. It is observed the nanoparticles are well shaped and the average particle size is 20 nm in the range of 5-50 nm. The antibacterial activity of these nanoparticles against Pseudomonas aeruginosa MTCC 741 has been measured by disc diffusion method, agar cup assay and serial dilution turbidity measurement assay. The results show green synthesized silver nanoparticles, using Vasaka leaf extract, have a potential to inhibit the growth of bacteria. PMID:25805902

  17. Alkylamine capped metal nanoparticle ``inks'' for printable SERS substrates, electronics and broadband photodetectors

    NASA Astrophysics Data System (ADS)

    Polavarapu, Lakshminarayana; Manga, Kiran Kumar; Yu, Kuai; Ang, Priscilla Kailian; Cao, Hanh Duyen; Balapanuru, Janardhan; Loh, Kian Ping; Xu, Qing-Hua

    2011-05-01

    We report a facile and general method for the preparation of alkylamine capped metal (Au and Ag) nanoparticle ``ink'' with high solubility. Using these metal nanoparticle ``inks'', we have demonstrated their applications for large scale fabrication of highly efficient surface enhanced Raman scattering (SERS) substrates by a facile solution processing method. These SERS substrates can detect analytes down to a few nM. The flexible plastic SERS substrates have also been demonstrated. The annealing temperature dependent conductivity of the nanoparticle films indicated a transition temperature above which high conductivity was achieved. The transition temperature could be tailored to the plastic compatible temperatures by using proper alkylamine as the capping agent. The ultrafast electron relaxation studies of the nanoparticle films demonstrated that faster electron relaxation was observed at higher annealing temperatures due to stronger electronic coupling between the nanoparticles. The applications of these highly concentrated alkylamine capped metal nanoparticle inks for the printable electronics were demonstrated by printing the oleylamine capped gold nanoparticles ink as source and drain for the graphene field effect transistor. Furthermore, the broadband photoresponse properties of the Au and Ag nanoparticle films have been demonstrated by using visible and near-infrared lasers. These investigations demonstrate that these nanoparticle ``inks'' are promising for applications in printable SERS substrates, electronics, and broadband photoresponse devices.We report a facile and general method for the preparation of alkylamine capped metal (Au and Ag) nanoparticle ``ink'' with high solubility. Using these metal nanoparticle ``inks'', we have demonstrated their applications for large scale fabrication of highly efficient surface enhanced Raman scattering (SERS) substrates by a facile solution processing method. These SERS substrates can detect analytes down to a few nM. The flexible plastic SERS substrates have also been demonstrated. The annealing temperature dependent conductivity of the nanoparticle films indicated a transition temperature above which high conductivity was achieved. The transition temperature could be tailored to the plastic compatible temperatures by using proper alkylamine as the capping agent. The ultrafast electron relaxation studies of the nanoparticle films demonstrated that faster electron relaxation was observed at higher annealing temperatures due to stronger electronic coupling between the nanoparticles. The applications of these highly concentrated alkylamine capped metal nanoparticle inks for the printable electronics were demonstrated by printing the oleylamine capped gold nanoparticles ink as source and drain for the graphene field effect transistor. Furthermore, the broadband photoresponse properties of the Au and Ag nanoparticle films have been demonstrated by using visible and near-infrared lasers. These investigations demonstrate that these nanoparticle ``inks'' are promising for applications in printable SERS substrates, electronics, and broadband photoresponse devices. Electronic Supplementary Information (ESI) available: Preparation of nanoparticle ink, SERS using gold nanoparticle films, SERS signals of 1 nM rhodamine 6G on oleylamine capped silver nanoparticle, Comparison of maximum SERS enhancement for Ag and Au nanoparticle substrates, surface morphology of gold nanoparticle film after annealing, ultrafast electron relaxation properties of the nanoparticle films, preparation of graphene oxide, multi-layer graphene film field-effect transistor (MLG-FET), Electric I-V characteristics of the Au and Ag nano particle films. See DOI: 10.1039/c0nr00972e/

  18. Synthesis of silver nanoparticles and antibacterial property of silk fabrics treated by silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Guangyu; Liu, Yan; Gao, Xiaoliang; Chen, Yuyue

    2014-05-01

    A silver nanoparticle solution was prepared in one step by mixing AgNO3 and a multi-amino compound (RSD-NH2) solution under ambient condition. RSD-NH2 was in-house synthesized by methacrylate and polyethylene polyamine in methanol, which has abundant amino and imino groups. However, the characterization of silver nanoparticles indicated that these nanoparticles are easy to agglomerate in solution. Therefore, an in situ synthesis method of silver nanoparticles on the silk fabrics was developed. The examined results confirmed that the in situ synthesized silver nanoparticles were evenly distributed on the surface of fibers. The inhibition zone test and the antibacterial rate demonstrated that the finished fabrics have an excellent antibacterial property against Staphylococcus aureus and Escherichia coli. Moreover, the nanosilver-treated silk fabrics were laundered 0, 5, 10, 20, and 50 times and still retained the exceptional antibacterial property. When the treated fabrics were washed 50 times, the antibacterial rate is more than 97.43% for S. aureus and 99.86% for E. coli. The excellent laundering durability may be attributed to the tight binding between silver nanoparticles and silk fibers through the in situ synthesis. This method provides an economic method to enhance the antibacterial capability of silk fabrics with good resistance to washings.

  19. Synthesis of silver nanoparticles and antibacterial property of silk fabrics treated by silver nanoparticles

    PubMed Central

    2014-01-01

    A silver nanoparticle solution was prepared in one step by mixing AgNO3 and a multi-amino compound (RSD-NH2) solution under ambient condition. RSD-NH2 was in-house synthesized by methacrylate and polyethylene polyamine in methanol, which has abundant amino and imino groups. However, the characterization of silver nanoparticles indicated that these nanoparticles are easy to agglomerate in solution. Therefore, an in situ synthesis method of silver nanoparticles on the silk fabrics was developed. The examined results confirmed that the in situ synthesized silver nanoparticles were evenly distributed on the surface of fibers. The inhibition zone test and the antibacterial rate demonstrated that the finished fabrics have an excellent antibacterial property against Staphylococcus aureus and Escherichia coli. Moreover, the nanosilver-treated silk fabrics were laundered 0, 5, 10, 20, and 50 times and still retained the exceptional antibacterial property. When the treated fabrics were washed 50 times, the antibacterial rate is more than 97.43% for S. aureus and 99.86% for E. coli. The excellent laundering durability may be attributed to the tight binding between silver nanoparticles and silk fibers through the in situ synthesis. This method provides an economic method to enhance the antibacterial capability of silk fabrics with good resistance to washings. PMID:24872803

  20. Printed UHF RFID antennas with high efficiencies using nano-particle silver ink.

    PubMed

    Lee, Yongshik; Kim, Chung Hwan; Shin, Dong-Youn; Kim, Young Gook

    2011-07-01

    One of the most popular targets of conductive ink technology is to print RFID tag antennas. However, the printed RFID antennas, manufactured by conductive silver ink which is generally based on microsized silver particles, have lower conductivity and consequently lower radiation efficiency than those by conventional copper etching method. This work demonstrates nano-particle conductive silver ink that is capable of printing UHF RFID antennas with improved radiation efficiency. Compared with commercial micro-particle silver ink, the solid content of metal is much higher in the proposed nanoparticle silver ink, leading to better electrical properties. Two types of dipole antennas are printed with the proposed nano-particle as well as with commercial micro-particle inks. Also, the same antennas are fabricated by copper etching. With these conductive inks, a straight and a meandered dipole antennas are fabricated and their radiation efficiencies are measured with the Wheeler cap method. Experimental results show that the radiation efficiencies of the antennas based on nanoparticle silver ink are superior to those printed with the micro-particle silver ink, and are comparable to those of popular copper antennas. PMID:22121728

  1. Silver nanoparticle-decorated porous ceramic composite for water treatment

    Microsoft Academic Search

    Yaohui Lv; Hong Liu; Zhen Wang; Shujiang Liu; Lujiang Hao; Yuanhua Sang; Duo Liu; Jiyang Wang; R. I. Boughton

    2009-01-01

    Silver nanoparticle-decorated porous ceramic composites have been prepared by overnight exposure to a sliver nanoparticle colloid solution of a porous ceramic modified by an aminosilane coupling agent, 3-aminopropyltriethoxysilane (APTES). The connection between the nanoparticle and the ceramic relies on the coordination bonds between the –NH2 group at the top of the APTES molecule and the silver atoms on the surface

  2. Characterization of enhanced antibacterial effects of novel silver nanoparticles

    Microsoft Academic Search

    Siddhartha Shrivastava; Tanmay Bera; Arnab Roy; Gajendra Singh; P. Ramachandrarao; Debabrata Dash

    2007-01-01

    In the present study, we report the preparation of silver nanoparticles in the range of 10-15 nm with increased stability and enhanced anti-bacterial potency. The morphology of the nanoparticles was characterized by transmission electron microscopy. The antibacterial effect of silver nanoparticles used in this study was found to be far more potent than that described in the earlier reports. This

  3. Biotemplates in the green synthesis of silver nanoparticles.

    PubMed

    Vijayaraghavan, Krishnan; Nalini, S P Kamala

    2010-10-01

    This article recapitulates the scientific advancement towards the greener synthesis of silver nanoparticles. Applications of noble metals have increased throughout human civilization, and the uses for nano-sized particles are even more remarkable. "Green" nanoparticle synthesis has been achieved using environmentally acceptable solvent systems and eco-friendly reducing and capping agents. Numerous microorganisms and plant extracts have been applied to synthesize inorganic nanostructures either intracellularly or extracellularly. The use of nanoparticles derived from noble metals has spread to many areas including jewelery, medical fields, electronics, water treatment and sport utilities, thus improving the longevity and comfort in human life. The application of nanoparticles as delivery vehicles for bactericidal agents represents a new paradigm in the design of antibacterial therapeutics. Orientation, size and physical properties of nanoparticles influences the performance and reproducibility of a potential device, thus making the synthesis and assembly of shape- and size-controlled nanocrystals an essential component for any practical application. This need has motivated researchers to explore different synthesis protocols. PMID:20669257

  4. Coarsening of silver nanoparticles in polyelectrolyte multilayers.

    PubMed

    Wei, Jingjing; Wang, Liming; Zhang, Xin; Ma, Xiaojing; Wang, Hui; Su, Zhaohui

    2013-09-10

    In polyelectrolyte multilayer (PEM) films assembled from poly(diallyldimethylammonium chloride) and poly(styrene sulfonate) via the layer-by-layer deposition technique, the counterions were exchanged with silver ions, which were subsequently reduced in situ to produce silver (Ag) nanoparticles. The Ag nanoparticles embedded in the PEMs were found to undergo an interesting coarsening process over time, through which smaller Ag nanoparticles coalesce into larger ones until reaching an equilibrium. The process was investigated by monitoring the localized surface plasmon resonance of the Ag nanoparticles using UV-vis extinction spectroscopy, and the spectral evolution revealed an increase in nanoparticle size with time, a trend in qualitative agreement with theoretical calculation and further confirmed by transmission electron microscopy. The kinetics of the coarsening process and the size of Ag nanoparticles at equilibrium were found to be affected by the PEM structure as well as the temperature and relative humidity the PEM was exposed to, and coalescence was identified to be the mechanism. PMID:23944934

  5. Solvothermal synthesis of silver nanoparticles from thiolates.

    PubMed

    Rosemary, M J; Pradeep, T

    2003-12-01

    A new solvothermal method for the synthesis of thiol-protected silver nanoparticles starting from silver thiolates is reported. The method has been tried with thiols of different chain length, such as octane and octadecane thiols, and the particle size was found to be nearly the same for both molecules. The synthesis was dependent on heating conditions and the best results were obtained when the temperature was between 180 and 200 degrees C. Addition of complexation agents such as acetyl acetone or triethylamine to the solvent did not change the product distribution significantly. PMID:14611776

  6. Silver nanoparticles produced by green production method

    NASA Astrophysics Data System (ADS)

    Bunghez, Ioana-Raluca; Ion, Rodica-Mariana; Velea, Sanda; Ilie, Lucia; Fierascu, Radu-Claudiu; Dumitriu, Irina; Dinu, Angela; Troncea, Simona

    2010-11-01

    Nanomaterials as novel materials with nanometer sizes are involved in higher performance technology. On this context nanobiotechnology is able to create different nanostructures using living organisms.An attractive research area is the application of microorganisms to synthesize nanoparticles from different metals, one of which is silver, an antimicrobial agent. Green production methods have a considerable interest for environmental protection, often based on plant extracts, organic compounds or microorganisms (bacteria, fungi, algae). Marine plants were used as "real factors" for synthesis of nanoparticles of Au and Ag using different processes of biomineralization. This paper deals with a complete study about obtaining silver nanoparticles from AgNO3 using red algae (Porphyridium purpureum). The red algae contain the red pigment-phycobilins, responsible for red color and for the strong absorption in visible spectrum. The properties and structure of silver nanoparticles have been put into evidence by means of: Fourier transform infrared spectroscopy-FTIR, optical microscopy, X-ray fluorescence spectrometry-EDXRF.

  7. Rapid biological synthesis of silver nanoparticles using plant leaf extracts

    Microsoft Academic Search

    Jae Yong Song; Beom Soo Kim

    2009-01-01

    Five plant leaf extracts (Pine, Persimmon, Ginkgo, Magnolia and Platanus) were used and compared for their extracellular synthesis\\u000a of metallic silver nanoparticles. Stable silver nanoparticles were formed by treating aqueous solution of AgNO3 with the plant leaf extracts as reducing agent of Ag+ to Ag0. UV-visible spectroscopy was used to monitor the quantitative formation of silver nanoparticles. Magnolia leaf broth

  8. Radiative properties of rare earth complexes\\/silver nanoparticles nanocomposite

    Microsoft Academic Search

    Si Wu; Youyi Sun; Xin Wang; Wenxuan Wu; Xiujie Tian; Qing Yan; Yanhua Luo; Qijin Zhang

    2007-01-01

    Rare earth complexes\\/silver nanoparticles nanocomposite was prepared by introducing Tb(TTA)3Bipy as stabilizer. The radiative properties of the nanocomposite were studied by experiments and spectra calculation. The transmission electron microscope image of the composite indicates that the silver nanoparticles are spherical, monodispersed and with an average size of 18nm. Fluorescence study shows silver nanoparticles have both enhancement effect and quenching effect

  9. Antibacterial and catalytic activities of green synthesized silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Bindhu, M. R.; Umadevi, M.

    2015-01-01

    The aqueous beetroot extract was used as reducing agent for silver nanoparticles synthesis. The synthesized nanoparticles were characterized using UV-visible spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The surface plasmon resonance peak of synthesized nanoparticles was observed at 438 nm. As the concentration of beetroot extract increases, absorption spectra shows blue shift with decreasing particle size. The prepared silver nanoparticles were well dispersed, spherical in shape with the average particle size of 15 nm. The prepared silver nanoparticles are effective in inhibiting the growth of both gram positive and gram negative bacteria. The prepared silver nanoparticles reveal faster catalytic activity. This natural method for synthesis of silver nanoparticles offers a valuable contribution in the area of green synthesis and nanotechnology avoiding the presence of hazardous and toxic solvents and waste.

  10. Synthesis of silver nanoparticles in aqueous aminopolycarboxylic acid solutions via ?-irradiation and hydrogen reduction.

    PubMed

    Malkar, Vishwabharati V; Mukherjee, Tulsi; Kapoor, Sudhir

    2014-11-01

    Formation of silver nanoparticles in the presence of various aminipolycarboxylic acids (APCAs) such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), and N,N,N',N?,N?,N?-triethylenetetraminehexaacetic acid (TTHA) was studied. Monodispersed silver nanoparticles capped by carboxylate groups of APCAs were prepared by the reduction of Ag(+) ions induced by either ?-radiolytic or H2 reduction at room temperature. APCAs act as stabilizer to avoid the aggregation of silver nanoparticles. It has been shown that H2-induced reduction of Ag(+) is possible at room temperature in the presence of APCAs. TTHA stabilized ?-reduced particles showed reactivity towards oxygen. The formed particles were characterized by UV-vis absorption, X-ray diffraction, zetasizer and transmission electron microscopy. PMID:25280683

  11. Antibacterial activity of biogenic silver nanoparticles synthesized with gum ghatti and gum olibanum: a comparative study.

    PubMed

    Kora, Aruna Jyothi; Sashidhar, Rao Beedu

    2015-02-01

    Presently, silver nanoparticles produced by biological methods have received considerable significance owing to the natural abundance of renewable, cost-effective and biodegradable materials, thus implementing the green chemistry principles. Compared with the nanoparticles synthesized using chemical methods, most biogenic silver nanoparticles are protein capped, which imparts stability and biocompatibility, and enhanced antibacterial activity. In this study, we compared the antibacterial effect of two biogenic silver nanoparticles produced with natural plant gums: gum ghatti and gum olibanum against Gram-negative and Gram-positive bacteria. Bacterial interaction with nanoparticles was probed both in planktonic and biofilm modes of growth; employing solid agar and liquid broth assays for inhibition zone, antibiofilm activity, inhibition of growth kinetics, leakage of intracellular contents, membrane permeabilization and reactive oxygen species production. In addition, cytotoxicity of the biogenic nanoparticles was evaluated in HeLa cells, a human carcinoma cell line. Antibacterial activity and cytotoxicity of the silver nanoparticles synthesized with gum ghatti (Ag NP-GT) was greater than that produced with gum olibanum (Ag NP-OB). This could be attributed to the smaller size (5.7?nm), monodispersity and zeta potential of the Ag NP-GT. The study suggests that Ag NP-GT can be employed as a cytotoxic bactericidal agent, whereas Ag NP-OB (7.5?nm) as a biocompatible bactericidal agent. PMID:25138141

  12. Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp

    PubMed Central

    Thomas, Roshmi; Janardhanan, Anju; Varghese, Rintu T.; Soniya, E.V.; Mathew, Jyothis; Radhakrishnan, E.K.

    2014-01-01

    Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm – 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus. PMID:25763025

  13. Aquatic Toxicity Comparison of Silver Nanoparticles and Silver Nanowires

    PubMed Central

    Kim, Tae Gyu; Kim, Jin Kwon; Kim, Ellen; Lee, Ji Hyun; Chung, Young Shin

    2015-01-01

    To better understand the potential ecotoxicological impact of silver nanoparticles (AgNPs) and silver nanowires (AgNWs) released into freshwater environments, the toxicities of these nanomaterials were assessed and compared using Organization for Economic Cooperation and Development (OECD) test guidelines, including a “Daphnia sp., acute immobilization test,” “Fish, acute toxicity test,” and “freshwater alga and cyanobacteria, growth inhibition test.” Based on the estimated median lethal/effective concentrations of AgNPs and AgNWs, the susceptibility to the nanomaterials was different among test organisms (daphnia > algae > fish), suggesting that the AgNPs are classified as “category acute 1” for Daphnia magna, “category acute 2” for Oryzias latipes, and “category acute 1” for Raphidocelis subcapitata, while the AgNWs are classified as “category acute 1” for Daphnia magna, “category acute 2” for Oryzias latipes, and “category acute 2” for Raphidocelis subcapitata, according to the GHS (Globally Harmonized System of Classification and Labelling of Chemicals). In conclusion, the present results suggest that more attention should be paid to prevent the accidental or intentional release of silver nanomaterials into freshwater aquatic environments. PMID:26125025

  14. Enhanced thermal stability of phosphate capped magnetite nanoparticles

    SciTech Connect

    Muthukumaran, T.; Philip, John, E-mail: philip@igcar.gov.in [SMARTS, Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu-603 102 (India)

    2014-06-14

    We have studied the effect of phosphate capping on the high temperature thermal stability and magnetic properties of magnetite (Fe{sub 3}O{sub 4}) nanoparticles synthesized through a single-step co-precipitation method. The prepared magnetic nanoparticles are characterized using various techniques. When annealed in air, the phosphate capped nanoparticle undergoes a magnetic to non-magnetic phase transition at a temperature of 689?°C as compared to 580?°C in the uncoated nanoparticle of similar size. The observed high temperature phase stability of phosphate capped nanoparticle is attributed to the formation of a phosphocarbonaceous shell over the nanoparticles, which acts as a covalently attached protective layer and improves the thermal stability of the core material by increasing the activation energy. The phosphocarbonaceous shell prevents the intrusion of heat, oxygen, volatiles, and mass into the magnetic core. At higher temperatures, the coalescence of nanoparticles occurs along with the restructuring of the phosphocarbonaceous shell into a vitreous semisolid layer on the nanoparticles, which is confirmed from the small angle X-ray scattering, Fourier transform infra red spectroscopy, and transmission electron microscopy measurements. The probable mechanism for the enhancement of thermal stability of phosphocarbonaceous capped nanoparticles is discussed.

  15. Production of silver nanoparticles by laser ablation in open air

    NASA Astrophysics Data System (ADS)

    Boutinguiza, M.; Comesaña, R.; Lusquiños, F.; Riveiro, A.; del Val, J.; Pou, J.

    2015-05-01

    Silver nanoparticles have attracted much attention as a subject of investigation due to their well-known properties, such as good conductivity, antibacterial and catalytic effects, etc. They are used in many different areas, such as medicine, industrial applications, scientific investigation, etc. There are different techniques for producing Ag nanoparticles, chemical, electrochemical, sonochemical, etc. These methods often lead to impurities together with nanoparticles or colloidal solutions. In this work, laser ablation of solids in open air conditions (LASOA) is used to produce silver nanoparticles and collect them on glass substrates. Production and deposition of silver nanoparticles are integrated in the same step to reduce the process. The obtained particles are analysed and the nanoparticles formation mechanism is discussed. The obtained nanoparticles were characterized by means of transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and UV/VIS absorption spectroscopy. The obtained nanoparticles consisted of Ag nanoparticles showing rounded shape with diameters ranging from few to 50 nm

  16. Transformation of Silver Nanoparticles in Fresh, Aged, and Incinerated Biosolids

    EPA Science Inventory

    Abstract The purpose of this research was to assess the chemical transformation of silver nanoparticles (AgNPs) in aged, fresh, and incinerated biosolids in order to provide information for AgNP life cycle analyses. Silver nanoparticles were introduced to the influent of a pilot...

  17. Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity.

    PubMed

    Ashraf, Sumaira; Akhtar, Nasrin; Ghauri, Muhammad Afzal; Rajoka, Muhammad Ibrahim; Khalid, Zafar M; Hussain, Irshad

    2012-01-01

    Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering, electrophoretic mobility, and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram-negative bacterial strain, Escherichia coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics. PMID:22625664

  18. Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Ashraf, Sumaira; Akhtar, Nasrin; Ghauri, Muhammad Afzal; Rajoka, Muhammad Ibrahim; Khalid, Zafar M.; Hussain, Irshad

    2012-05-01

    Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering, electrophoretic mobility, and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram-negative bacterial strain, Escherichia coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics.

  19. Impact of Environmental Conditions (pH, Ionic Strength, And Electrolyte Type) On The Surface Charge And Aggregation Of Silver Nanoparticles Suspensions

    EPA Science Inventory

    The impact of capping agents and environmental conditions (pH, ionic strength, and background electrolytes) on surface charge and aggregation potential of silver nanoparticles (AgNPs) suspensions were investigated. Capping agents are chemicals used in the synthesis of nanopartic...

  20. Synthesis of Starch - Stabilized Silver Nanoparticles and Their Antimicrobial Activity

    Microsoft Academic Search

    V. RAJI; M. CHAKRABORTY; P. A. PARIKH

    2012-01-01

    In this study silver nanoparticles were prepared using silver nitrate as the metal precursor, starch as protecting agent and sodium borohydride (NaBH4) as a reducing agent by chemical reduction method. The formation of the silver nanoparticles was monitored using UV-Vis absorption spectroscopy, cyclic voltammetry and particle size analyzer and characterized by Transmission Electron microscopy (TEM) and X-Ray Diffraction (XRD).Synthesis of

  1. Silver nanoparticles ink synthesis for conductive patterns fabrication using inkjet printing technology

    NASA Astrophysics Data System (ADS)

    Chien Dang, Mau; Dung Dang, Thi My; Fribourg-Blanc, Eric

    2015-03-01

    In this paper we present silver nanoparticles ink synthesis targeting conductive patterns for micro fabricated devices by inkjet printing technology. The well dispersed nanoparticles ink was composed of silver colloid with an average particle diameter less than 10 nm. These nanoparticles were protected by a capping layer of poly(N-vinylpyrrolidone) (PVP) even at silver concentration of 20 wt%. Stable aqueous inks were formulated by using a combination of solvent and co-solvents and under vigorous stirring. Various factors affecting the adhesion between the ink and the substrate were investigated, such as solvent and co-solvent content. The ink containing 20 wt% silver has a viscosity of about 9.5 cP and a surface tension of 32 to 36 mN m?1 at room temperature, meeting inkjet printer requirements. The ink stored under ambient conditions was stable against aggregation for more than one month. Silver nanoparticles patterns have been successfully printed on various substrates. Invited talk at the 7th International Workshop on Advanced Materials Science and Nanotechnology IWAMSN2014, 2-6 November, 2014, Ha Long, Vietnam.

  2. Remobilisation of silver and silver sulphide nanoparticles in soils.

    PubMed

    Navarro, Divina A; Kirby, Jason K; McLaughlin, Mike J; Waddington, Lynne; Kookana, Rai S

    2014-10-01

    Manufactured nanoparticles (NPs) present in consumer products could enter soils through re-use of biosolids. Among these NPs are those based on silver (Ag), which are found sulphidised (e.g. silver sulphide, Ag2S) in biosolids. Herein, our aim was to examine the release of retained Ag(0) and Ag2S NPs in soils and biosolids as facilitated by environmentally and agriculturally relevant ligands. Under natural soil conditions, exemplified by potassium nitrate and humic acid experiments, release of Ag retained in soil was limited. The highest total Ag release was facilitated by ligands that simulated root exudates (citrate) or fertilisers (thiosulphate). Released Ag was predominantly present in the colloidal phase (>3 kDa-< 0.45 ?m); intact NPs only identified in Ag2S-NP extracts. For biosolids containing nanoparticulate-Ag-S, release was also enhanced by thiosulphate, though mostly as colloidal-Ag - not intact NPs. These results suggest that exposure to NPs as a result of its release from soils or biosolids will be low. PMID:25014017

  3. Facile method to synthesize oleic acid-capped magnetite nanoparticles

    Microsoft Academic Search

    Chun Yu Wang; Jian Ming Hong; Gong Chen; Yu Zhang; Ning Gu

    2010-01-01

    We described a simple one-step process for the synthesis of oleic acid-capped magnetite nanoparticles using the dimethyl sulfoxide (DMSO) to oxidize the precursor Fe2+ at 140°C. By adjusting the alkalinity of the reaction system, magnetite nanoparticles with two sizes of 4 and 7nm could be easily achieved. And the magnetite nanoparticles coated by oleate were well-monodispersed in organic solvent.

  4. Anti-Bacterial Properties of Silver Nanoparticles

    NSDL National Science Digital Library

    This lesson from The Lawrence Hall of Science was taught in spring 2013 and focuses on synthesizing and testing silver nanoparticles. The three part lab involves "synthesis, testing and characterization and was implemented with a collaborative model." Each part of the lab is to be completed by a different class of students - those studying chemistry, biology, and engineering, respectively. This page includes links to Source Articles for the Hands-on Module, the Project Staff Write-up of the Hands-on Module, as well as a PowerPoint presentation and three documents detailing the labs.

  5. Biological coating of paper using silver nanoparticles.

    PubMed

    Ghorbani, Hamid Reza

    2014-12-01

    The capacity of Ag nanoparticles to destroy various micro-organisms makes it one of the most powerful antimicrobial agents, an attractive feature against antibiotic resistant bacteria. Here, a simple method to develop coating of colloidal silver on paper using a biological method is presented. The coated paper was studied by scanning electron microscopy, X-ray diffraction technique and atomic absorption spectroscopy. The antibacterial activity of the coated paper against Escherichia coli and Staphylococcus aureus was measured by agar diffusion method. This study shows the potential use of the coated paper as a food antimicrobial packing material for longer shelf life. PMID:25429506

  6. Formation of silver microbelt structures by laser irradiation of silver nanoparticles in ethanol

    PubMed Central

    Zamiri, Reza; Zakaria, Azmi; Husin, Mohd Shahril; Wahab, Zaidan Abd; Nazarpour, Forough Kalaei

    2011-01-01

    In the present work, we prepared silver nanoparticles by laser ablation of pure silver plate in ethanol and then irradiated the silver nanoparticles using a 532 nm Q-switched Nd:YAG pulsed laser. Transmission electron microscopic images of the sample after irradiation clearly showed formation of big structures, such as microrods and microbelts in ethanol. The obtained microbelts had a width of about 0.166 ?m and a length of 1.472 ?m. The reason for the formation of such a big structure is the tendency of the nanoparticles to aggregate in ethanol before irradiation, which causes fusion of the nanoparticles. PMID:22114485

  7. Toxicity of Silver Nanoparticles at the Air-Liquid Interface

    PubMed Central

    Holder, Amara L.; Marr, Linsey C.

    2013-01-01

    Silver nanoparticles are one of the most prevalent nanomaterials in consumer products. Some of these products are likely to be aerosolized, making silver nanoparticles a high priority for inhalation toxicity assessment. To study the inhalation toxicity of silver nanoparticles, we have exposed cultured lung cells to them at the air-liquid interface. Cells were exposed to suspensions of silver or nickel oxide (positive control) nanoparticles at concentrations of 2.6, 6.6, and 13.2??g cm?2 (volume concentrations of 10, 25, and 50??g?ml?1) and to 0.7??g?cm?2 silver or 2.1??g?cm?2 nickel oxide aerosol at the air-liquid interface. Unlike a number of in vitro studies employing suspensions of silver nanoparticles, which have shown strong toxic effects, both suspensions and aerosolized nanoparticles caused negligible cytotoxicity and only a mild inflammatory response, in agreement with animal exposures. Additionally, we have developed a novel method using a differential mobility analyzer to select aerosolized nanoparticles of a single diameter to assess the size-dependent toxicity of silver nanoparticles. PMID:23484109

  8. Biosynthesis, characterization, and antimicrobial applications of silver nanoparticles.

    PubMed

    Singh, Priyanka; Kim, Yeon Ju; Singh, Hina; Wang, Chao; Hwang, Kyu Hyon; Farh, Mohamed El-Agamy; Yang, Deok Chun

    2015-01-01

    In the present study, the strain Brevibacterium frigoritolerans DC2 was explored for the efficient and extracellular synthesis of silver nanoparticles. These biosynthesized silver nanoparticles were characterized by ultraviolet-visible spectrophotometry, which detected the formation of silver nanoparticles in the reaction mixture and showed a maximum absorbance at 420 nm. In addition, field emission transmission electron microscopy revealed the spherical shape of the nanoparticles. The dynamic light scattering results indicated the average particle size of the product was 97 nm with a 0.191 polydispersity index. Furthermore, the product was analyzed by energy dispersive X-ray spectroscopy, X-ray diffraction, and elemental mapping, which displayed the presence of elemental silver in the product. Moreover, on a medical platform, the product was checked against pathogenic microorganisms including Vibrio parahaemolyticus, Salmonella enterica, Bacillus anthracis, Bacillus cereus, Escherichia coli, and Candida albicans. The nanoparticles demonstrated antimicrobial activity against all of these pathogenic microorganisms. Additionally, the silver nanoparticles were evaluated for their combined effects with the commercial antibiotics lincomycin, oleandomycin, vancomycin, novobiocin, penicillin G, and rifampicin against these pathogenic microorganisms. These results indicated that the combination of antibiotics with biosynthesized silver nanoparticles enhanced the antimicrobial effects of antibiotics. Therefore, the current study is a demonstration of an efficient biological synthesis of silver nanoparticles by B. frigoritolerans DC2 and its effect on the enhancement of the antimicrobial efficacy of well-known commercial antibiotics. PMID:25848272

  9. Bio-conjugated silver nanoparticles: from Ocimum sanctum and role of cetyltrimethyl ammonium bromide.

    PubMed

    Zaheer, Zoya; Rafiuddin

    2013-08-01

    In this paper we have reported the spectrophotometeric and transmission electron microscopic (TEM) data to the shape-directing role of cetyltrimethylammonium bromide (CTAB) on the green extra-cellular synthesis of bio-conjugated Ag-nanoparticles using Ocimum sanctum leaves extract. TEM images revealed that the nanoparticles are mostly spherical (average particle size ranged from 18 to 35nm) with some truncated triangular nanoplates, aggregated in a beautiful manner to yield locket-like silver and capped by a thin layer of biomolecules of O. sanctum, whereas nanoparticles are highly poly-dispersed in presence of CTAB. The shape and position of wavelength maxima strongly depends on the reaction time, [leaves extract] and [CTAB]. The visual observations also suggest that the prefect transparent silver sol becomes turbid in presence of CTAB after some time. PMID:23524081

  10. Shape effects in plasmon resonance of individual colloidal silver nanoparticles

    Microsoft Academic Search

    J. J. Mock; M. Barbic; D. R. Smith; D. A. Schultz; S. Schultz

    2002-01-01

    We present a systematic study of the effect of size and shape on the spectral response of individual silver nanoparticles. An experimental method has been developed that begins with the detection and characterization of isolated nanoparticles in the optical far field. The plasmon resonance optical spectrum of many individual nanoparticles are then correlated to their size and shape using high-resolution

  11. Development of nanostructured silver vanadates decorated with silver nanoparticles as a novel antibacterial agent

    NASA Astrophysics Data System (ADS)

    Holtz, R. D.; Souza Filho, A. G.; Brocchi, M.; Martins, D.; Durán, N.; Alves, O. L.

    2010-05-01

    In this work we report the synthesis, characterization and application of silver vanadate nanowires decorated with silver nanoparticles as a novel antibacterial agent. These hybrid materials were synthesized by a precipitation reaction of ammonium vanadate and silver nitrate followed by hydrothermal treatment. The silver vanadate nanowires have lengths of the order of microns and diameters around 60 nm. The silver nanoparticles decorating the nanowires present a diameter distribution varying from 1 to 20 nm. The influence of the pH of the reaction medium on the chemical structure and morphology of silver vanadates was studied and we found that synthesis performed at pH 5.5-6.0 led to silver vanadate nanowires with a higher morphological yield. The antimicrobial activity of these materials was evaluated against three strains of Staphylococcus aureus and very promising results were found. The minimum growth inhibiting concentration value against a MRSA strain was found to be ten folds lower than for the antibiotic oxacillin.

  12. Separation and measurement of silver nanoparticles and silver ions using magnetic particles.

    PubMed

    Mwilu, Samuel K; Siska, Emily; Baig, R B Nasir; Varma, Rajender S; Heithmar, Ed; Rogers, Kim R

    2014-02-15

    The recent surge in consumer products and applications using metallic nanoparticles has increased the possibility of human or ecosystem exposure due to unintentional release into the environment. To protect consumer health and the environment, there is an urgent need to develop tools that can characterize and quantify these materials at low concentrations and in complex matrices. In this study, magnetic nanoparticles coated with either dopamine or glutathione were used to develop a new, simple and reliable method for the separation/pre-concentration of trace amounts of silver nanoparticles followed by their quantification using inductively coupled plasma mass spectrometry (ICP-MS). The structurally modified magnetic particles were able to capture trace amounts of silver nanoparticles (~2 ppb) and concentrate (up to 250 times) the particles for analysis with ICP-MS. Under laboratory conditions, recovery of silver nanoparticles was >99%. More importantly, the magnetic particles selectively captured silver nanoparticles in a mixture containing both nano-particulate and ionic silver. This unique feature addresses the challenges of separation and quantification of silver nanoparticles in addition to the total silver in environmental samples. Spiking experiments showed recoveries higher than 97% for tap water and both fresh and saline surface water. PMID:24295749

  13. Multiple thiol-anchor capped DNA-gold nanoparticle conjugates

    Microsoft Academic Search

    Zhi Li; Rongchao Jin; Chad A. Mirkin; Robert L. Letsinger

    2002-01-01

    We report the synthesis of a novel trithiol-capped oligodeoxyribonucleotide and gold nanoparticle conjugates prepared from it. These DNA-gold nano- particle conjugates exhibit substantially higher stability than analogs prepared from monothiol and cyclic disulfide-capped oligodeoxyribonucleotides, but comparable hybridization properties. A quantita- tive analysis of their stability under a range of condi- tions is provided. Significantly, this novel trithiol oligodeoxyribonucleotide can be

  14. Characterization and antimicrobial activity of silver nanoparticles prepared by a thermal decomposition technique

    NASA Astrophysics Data System (ADS)

    Tam, Le Thi; Phan, Vu Ngoc; Lan, Hoang; Thuy, Nguyen Thanh; Hien, Tran Minh; Huy, Tran Quang; Quy, Nguyen Van; Chinh, Huynh Dang; Tung, Le Minh; Tuan, Pham Anh; Lam, Vu Dinh; Le, Anh-Tuan

    2013-11-01

    Recently, there has been an increasing need of efficient synthetic protocols using eco-friendly conditions including low costs and green chemicals for production of metal nanoparticles. In this work, silver nanoparticles (silver NPs) with average particle size about 10 nm were synthesized by using a thermal decomposition technique. Unlike the colloidal chemistry method, the thermal decomposition method developed has advantages such as the high crystallinity, single-reaction synthesis, and easy dispersion ability of the synthesized NPs in organic solvents. In a modified synthesis process, we used sodium oleate as a capping agent to modify the surface of silver NPs because the oleate has a C18 tail with a double bond in the middle, therefore, forming a kink which is to be effective for aggregative stability. Importantly, the as-synthesized silver NPs have demonstrated strong antimicrobial effects against various bacteria and fungi strains. Electron microscopic studies reveal physical insights into the interaction and bactericidal mechanism between the prepared silver NPs and tested bacteria in question. The observed excellent antibacterial and antifungal activity of the silver NPs make them ideal for disinfection and biomedicine applications.

  15. Structural characterisation of alkyl amine-capped zinc sulphide nanoparticles

    PubMed Central

    Kremser, Gabriele; Rath, Thomas; Kunert, Birgit; Edler, Michael; Fritz-Popovski, Gerhard; Resel, Roland; Letofsky-Papst, Ilse; Grogger, Werner; Trimmel, Gregor

    2012-01-01

    Nanoparticles capped with amine ligands with different steric properties, dodecylamine and oleylamine, respectively, are investigated in the solid state as well as in solution. A combined X-ray diffraction, small angle X-ray scattering and electron microscopy investigation showed that the nanoparticles exhibit the sphalerite modification of ZnS as crystal phase with a diameter of 3–5 nm. A close packing of the monocrystalline nanoparticles in the solid state is observed. However, in the dodecylamine sample, besides spherical particles, a fraction of the nanoparticles is elongated. The nanoparticles are readily resoluble in apolar solvents like hexane. Dynamic light scattering (DLS) and SAXS investigations of the solutions reveal that the nanoparticles are dissolved as singular particles. In the case of oleylamine-capped ZnS, a defined core–shell structure with a ZnS core with a diameter of 4 nm and an organic shell with a thickness of approximately 2 nm have been found. Dodecylamine-capped nanoparticles slightly tend to form agglomerates with a diameter of approximately 40 nm. PMID:22239986

  16. Catalytically and biologically active silver nanoparticles synthesized using essential oil.

    PubMed

    Vilas, Vidya; Philip, Daizy; Mathew, Joseph

    2014-11-11

    There are numerous reports on phytosynthesis of silver nanoparticles and various phytochemicals are involved in the reduction and stabilization. Pure explicit phytosynthetic protocol for catalytically and biologically active silver nanoparticles is of importance as it is an environmentally benign green method. This paper reports the use of essential oil of Myristica fragrans enriched in terpenes and phenyl propenes in the reduction and stabilization. FTIR spectra of the essential oil and the synthesized biogenic silver nanoparticles are in accordance with the GC-MS spectral analysis reports. Nanosilver is initially characterized by an intense SPR band around 420 nm, followed by XRD and TEM analysis revealing the formation of 12-26 nm sized, highly pure, crystalline silver nanoparticles. Excellent catalytic and bioactive potential of the silver nanoparticles is due to the surface modification. The chemocatalytic potential of nanosilver is exhibited by the rapid reduction of the organic pollutant, para nitro phenol and by the degradation of the thiazine dye, methylene blue. Significant antibacterial activity of the silver colloid against Gram positive, Staphylococcus aureus (inhibition zone--12 mm) and Gram negative, Escherichia coli (inhibition zone--14 mm) is demonstrated by Agar-well diffusion method. Strong antioxidant activity of the biogenic silver nanoparticles is depicted through NO scavenging, hydrogen peroxide scavenging, reducing power, DPPH and total antioxidant activity assays. PMID:24956490

  17. Transformation of aromatic dyes using green synthesized silver nanoparticles.

    PubMed

    Borase, Hemant P; Patil, Chandrashekhar D; Salunkhe, Rahul B; Suryawanshi, Rahul K; Salunke, Bipinchandra K; Patil, Satish V

    2014-08-01

    Nowadays, increasing use of nanoproducts in area of human and environmental applications raises concern about safety aspects of nanoparticles synthesized using traditional physicochemical methods. Silver nanoparticles (AgNPs) synthesis at ambient parameters using latex of medicinally important plant Jatropha gossypifolia (J. gossypifolia) is reported in the present study. Potential of AgNPs in degradation of methylene blue and eosin B was also evaluated. Rapid formation of stable AgNPs was analyzed by visual color change from colorless to yellow-red after addition of latex in AgNO3 solution and by characteristic surface plasmon resonance (SPR) peak at 430 nm in UV-Vis spectroscopy. FT-IR analysis, protein coagulation test showed capping of proteins, flavonoids, terpenoids and polyphenols of latex on surface of AgNPs. FE-SEM, HR-TEM analysis revealed spherical shape of AgNPs. Narrow size range of AgNPs (5-40 nm) observed in HR-TEM analysis. EDS analysis confirms the presence of elemental silver while XRD revealed crystalline nature of AgNPs. Zeta potential of -21.4 mV indicates high stability of AgNPs. Effects of different parameters (pH, temperature, incubation time) on nanosynthesis were studied in the present study. Dye reduction studies were performed using UV-Vis spectroscopy, TLC, FT-IR and HPLC analysis showing decreased absorbance maxima of both dyes with respect to time, change in R f values, changes in wave number, transmittance, and retention time of dyes after AgNPs addition. The rate constant for methylene blue and eosin B reduction by AgNPs was found to be 0.062 and 0.022 min(-1). PMID:24525834

  18. Nanoparticle Spectroscopy: Birefringence in Two-Dimensional Arrays of L-Shaped Silver Nanoparticles

    E-print Network

    Seideman, Tamar

    Nanoparticle Spectroscopy: Birefringence in Two-Dimensional Arrays of L-Shaped Silver Nanoparticles optical birefringence. The experiments use polarization optical methods to describe the birefringence birefringence materials with the same thickness. This study suggests the possible application of two

  19. Characterization and Biocompatibility of ``Green'' Synthesized Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Moulton, Michael; Kunzelman, Samantha; Braydich-Stolle, Laura; Nadagouda, M.; Varma, R.; Hussain, Saber

    2008-10-01

    With ever increasing emphasis on nanotechnology, silver nanoparticle are being considered for many antimicrobial needs ranging from catheter coatings, to burn wound bandages. Current synthesis methods for creating silver nanoparticles typically call for potentially hazardous chemicals, extreme heat, and produce environmentally dangerous byproducts. As a culture intent on reducing our carbon footprint on the earth, societies' focus has turned to ``green'' production capabilities. Therefore, if nanotechnology is to continue to grow at its current rate it is essential that novel ``green'' synthesis of nanoparticles becomes a reality. Furthermore, with the current and near-future applications of silver nanoparticles in biological systems it is imperative to fully analyze the potential toxic effects of these nanoparticles. In this study we have shown that by reducing silver nitrate in solutions of tea extract or epinephrine of varying concentrations spherical silver nanoparticle are formed. Furthermore, evaluation of mitochondrial function (MTS) and membrane integrity (LDH) in alveolar rat macrophages and human keratinocytes showed that these ``green'' synthesized silver nanoparticles were nontoxic.

  20. Hair follicles stimulation effects of gelatin nanofibers containing silver nanoparticles.

    PubMed

    Tura, V; Hagiu, B A; Mangalagiu, I I

    2010-04-01

    In the present work we studied gelatin nanofibers containing silver nanoparticles of 14 +/- 6 nm mean diameter, prepared by electrospinning. The electrospinnable solution was obtained by drop-wise adding a AgNO3/acetic acid solution to gelatin which had previously been dissolved in a mixture of formic acid and acetic acid. The silver metallic nanoparticles were formed due to the reducing action of the formic acid. The resulted material was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD). Subcutaneous implants in rabbits demonstrated that the gelatin nanofibers containing silver nanoparticles were resorbed with no inflammatory reactions. An increased number of secondary hair follicles developed in tissue regions close to implants, suggesting the existence of a stimulation effect of silver nanoparticles on hair follicles. PMID:20738075

  1. Fate of Zinc and Silver Engineered Nanoparticles in Sewerage Networks

    EPA Science Inventory

    Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage sy...

  2. Silver nanoparticle structures realized by digital surface micromachining

    E-print Network

    Schmidt, Martin Arnold

    We report a new surface micromachining process using commercial silver nanoparticle inks and digital fabrication methods. This process is entirely digital (non-lithographic patterning), the feature sizes can be <20 mum, ...

  3. Silver Nanoparticles Part 1: Synthesis and Spectroscopy

    NSDL National Science Digital Library

    The NACK Center is an organization committed to supporting two â??year degree programs in micro and nanotechnology. The center offers online educational material for curriculum enhancement in this subject field. One of these resources is a lab documentation focusing on the topic of silver nanoparticles. The lab is "designed for an advanced chemistry class, but may also be done with first year student. Prior experience with spectroscopy is recommended.â? The lesson includes objectives, sample solution preparations, and sample data and calculations. Overall, the objectives of this lesson are to demonstrate the use of a spectrophotometer, the observation of nanoscale physical properties and conversion of different unit measurements. The site requires a free log-in for access to the material.

  4. Antimicrobial surface functionalization of plastic catheters by silver nanoparticles

    Microsoft Academic Search

    David Roe; Balu Karandikar; Nathan Bonn-Savage; Bruce Gibbins; Jean-Baptiste Roullet

    2008-01-01

    Objectives: To test the antimicrobial activity and evaluate the risk of systemic toxicity of novel catheters coated with silver nanoparticles. Methods: Catheters were coated with silver using AgNO3, a surfactant and N,N,N 0,N 0-tetramethylethy- lenediamine as a reducing agent. Particle size was determined by electron microscopy. Silver release from the catheters was determined in vitro and in vivo using radioactive

  5. Synthesis and characterization of silver nanoparticles in AOT microemulsion system

    Microsoft Academic Search

    Wanzhong Zhang; Xueliang Qiao; Jianguo Chen

    2006-01-01

    Colloidal silver nanoparticles have been synthesized in water-in-oil microemulsion using silver nitrate solubilized in the water core of one microemulsion as source of silver ions, hydrazine hydrate solubilized in the water core of another microemulsion as reducing agent, dodecane as the oil phase, sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as the surfactant. The UV–vis absorption spectra and transmission electron microscopy (TEM) have

  6. Dispersibility of organically coated silver nanoparticles in organic media

    Microsoft Academic Search

    Connie Manz; Lee Williams; Ray Mohseni; Eugene Zlotnikov; Aleksey Vasiliev

    2011-01-01

    Coating of organophobic silver nano-particles with thiols was applied to facilitate their dispersing in aprotic organic solvents and solutions of polyacrylic acid and polylactide. Impact of chemical nature of thiols and dipole moment of the solvents on dispersibility of the modified silver particles was studied by UV–Vis spectroscopy (surface plasmon resonance) and scanning electron microscopy. It was shown that thiols’

  7. Characterization and Biocompatibility of Green Synthesized Silver Nanoparticles

    EPA Science Inventory

    There are currently ~1,000 commercially available products which contain some form of silver nanotechnology, ranging from topological creams and cosmetics, to anti-microbial socks and household cleansers. Previous studies have indicated that silver nanoparticles (Ag NPs) have a ...

  8. Green synthesis of silver and gold nanoparticles using Zingiber officinale root extract and antibacterial activity of silver nanoparticles against food pathogens.

    PubMed

    Velmurugan, Palanivel; Anbalagan, Krishnan; Manosathyadevan, Manoharan; Lee, Kui-Jae; Cho, Min; Lee, Sang-Myeong; Park, Jung-Hee; Oh, Sae-Gang; Bang, Keuk-Soo; Oh, Byung-Taek

    2014-10-01

    In the present study, we synthesized silver and gold nanoparticles with a particle size of 10-20 nm, using Zingiber officinale root extract as a reducing and capping agent. Chloroauric acid (HAuCl4) and silver nitrate (AgNO3) were mixed with Z. officinale root extract for the production of silver (AgNPs) and gold nanoparticles (AuNPs). The surface plasmon absorbance spectra of AgNPs and AuNPs were observed at 436-531 nm, respectively. Optimum nanoparticle production was achieved at pH 8 and 9, 1 mM metal ion, a reaction temperature 50 °C and reaction time of 150-180 min for AgNPs and AuNPs, respectively. An energy-dispersive X-ray spectroscopy (SEM-EDS) study provides proof for the purity of AgNPs and AuNPs. Transmission electron microscopy images show the diameter of well-dispersed AgNPs (10-20 nm) and AuNPs (5-20 nm). The nanocrystalline phase of Ag and Au with FCC crystal structures have been confirmed by X-ray diffraction analysis. Fourier transform infrared spectroscopy analysis shows the respective peaks for the potential biomolecules in the ginger rhizome extract, which are responsible for the reduction in metal ions and synthesized AgNPs and AuNPs. In addition, the synthesized AgNPs showed a moderate antibacterial activity against bacterial food pathogens. PMID:24668029

  9. Antibacterial properties of silver nanoparticles synthesized using Pulicaria glutinosa plant extract as a green bioreductant

    PubMed Central

    Khan, Mujeeb; Khan, Shams Tabrez; Khan, Merajuddin; Adil, Syed Farooq; Musarrat, Javed; Al-Khedhairy, Abdulaziz A; Al-Warthan, Abdulrahman; Siddiqui, Mohammed Rafiq H; Alkhathlan, Hamad Z

    2014-01-01

    The antibacterial properties of nanoparticles (NPs) can be significantly enhanced by increasing the wettability or solubility of NPs in aqueous medium. In this study, we investigated the effects of the stabilizing agent on the solubility of silver NPs and its subsequent effect on their antimicrobial activities. Silver NPs were prepared using an aqueous solution of Pulicaria glutinosa plant extract as bioreductant. The solution also acts as a capping ligand. During this study, the antimicrobial activities of silver NPs, as well as the plant extract alone, were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Micrococcus luteus. Silver NPs were prepared with various concentrations of the plant extract to study its effect on antimicrobial activity. Interestingly, various concentrations of P. glutinosa extract did not show any effect on the growth of tested bacteria; however, a significant effect on the antimicrobial property of plant extract capped silver NPs (Ag-NPs-PE) was observed. For instance, the half maximal inhibitory concentration values were found to decrease (from 4% to 21%) with the increasing concentrations of plant extract used for the synthesis of Ag-NPs-PE. These results clearly indicate that the addition of P. glutinosa extracts enhances the solubility of Ag-NPs-PE and, hence, increases their toxicity against the tested microorganisms. PMID:25114525

  10. Preparation, characterization, and surface modification of silver nanoparticles in formamide.

    PubMed

    Sarkar, Anjana; Kapoor, Sudhir; Mukherjee, Tulsi

    2005-04-28

    The reduction of silver ions in formamide is shown to take place spontaneously at room temperature without addition of any reductant. The growth of Ag particles was found to be dependent on Ag+ ion concentration. In the absence of any stabilizer, deposition of silver film on the glass walls of the container takes place. However, in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) or colloidal silica (SiO2), which are capable of stabilizing silver nanoparticles by complexing and providing support, a clear dispersion was obtained. The formation of the silver nanoparticles under different conditions was investigated through UV-visible absorption spectrophotometry, gas chromatography, and also electron and atomic force microscopic techniques. Atomic force microscopy results for silver films prepared in the absence of any stabilizer showed the formation of polygonal particles with sizes around 100 nm. Transmission electron microscopy results showed that the prepared silver particles in the presence of PVP were around 20 nm. The Ag nanoparticles get oxidized in the presence of chloroform and toluene. Surface modification of silver film was done in the presence of the tetrasodium salt of ethylenediaminetetraaceticacid (Na4EDTA). It was shown that the reactivity of the silver film increased in its presence. The Fermi potential of silver particles in the presence of Na4EDTA seems to lie between -0.33 and -0.446 V vs NHE. PMID:16851894

  11. Silver nanoparticle applications and human health.

    PubMed

    Ahamed, Maqusood; Alsalhi, Mohamad S; Siddiqui, M K J

    2010-12-14

    Nanotechnology is rapidly growing with nanoparticles produced and utilized in a wide range of commercial products throughout the world. For example, silver nanoparticles (Ag NP) are used in electronics, bio-sensing, clothing, food industry, paints, sunscreens, cosmetics and medical devices. These broad applications, however, increase human exposure and thus the potential risk related to their short- and long-term toxicity. A large number of in vitro studies indicate that Ag NPs are toxic to the mammalian cells derived from skin, liver, lung, brain, vascular system and reproductive organs. Interestingly, some studies have shown that this particle has the potential to induce genes associated with cell cycle progression, DNA damage and apoptosis in human cells at non-cytotoxic doses. Furthermore, in vivo bio-distribution and toxicity studies in rats and mice have demonstrated that Ag NP administered by inhalation, ingestion or intra-peritoneal injection were subsequently detected in blood and caused toxicity in several organs including brain. Moreover, Ag NP exerted developmental and structural malformations in non-mammalian model organisms typically used to elucidate human disease and developmental abnormalities. The mechanisms for Ag NP induced toxicity include the effects of this particle on cell membranes, mitochondria and genetic material. This paper summarizes and critically assesses the current studies focusing on adverse effects of Ag NPs on human health. PMID:20719239

  12. Cellular oxido-reductive proteins of Chlamydomonas reinhardtii control the biosynthesis of silver nanoparticles

    PubMed Central

    2011-01-01

    Background Elucidation of molecular mechanism of silver nanoparticles (SNPs) biosynthesis is important to control its size, shape and monodispersity. The evaluation of molecular mechanism of biosynthesis of SNPs is of prime importance for the commercialization and methodology development for controlling the shape and size (uniform distribution) of SNPs. The unicellular algae Chlamydomonas reinhardtii was exploited as a model system to elucidate the role of cellular proteins in SNPs biosynthesis. Results The C. reinhardtii cell free extract (in vitro) and in vivo cells mediated synthesis of silver nanoparticles reveals SNPs of size range 5 ± 1 to 15 ± 2 nm and 5 ± 1 to 35 ± 5 nm respectively. In vivo biosynthesized SNPs were localized in the peripheral cytoplasm and at one side of flagella root, the site of pathway of ATP transport and its synthesis related enzymes. This provides an evidence for the involvement of oxidoreductive proteins in biosynthesis and stabilization of SNPs. Alteration in size distribution and decrease of synthesis rate of SNPs in protein-depleted fractions confirmed the involvement of cellular proteins in SNPs biosynthesis. Spectroscopic and SDS-PAGE analysis indicate the association of various proteins on C. reinhardtii mediated in vivo and in vitro biosynthesized SNPs. We have identified various cellular proteins associated with biosynthesized (in vivo and in vitro) SNPs by using MALDI-MS-MS, like ATP synthase, superoxide dismutase, carbonic anhydrase, ferredoxin-NADP+ reductase, histone etc. However, these proteins were not associated on the incubation of pre-synthesized silver nanoparticles in vitro. Conclusion Present study provides the indication of involvement of molecular machinery and various cellular proteins in the biosynthesis of silver nanoparticles. In this report, the study is mainly focused towards understanding the role of diverse cellular protein in the synthesis and capping of silver nanoparticles using C. reinhardtii as a model system. PMID:22152042

  13. Impregnation of silver nanoparticles into polysaccharide substrates and their properties.

    PubMed

    Hassabo, Ahmed G; Nada, Ahmed A; Ibrahim, Hassan M; Abou-Zeid, N Y

    2015-05-20

    A method to impregnate silver nanoparticles (AgNPs) into different polysaccharides substrates (cellulose powder (CP), microcrystalline cellulose (MCC), carboxymethyl cellulose (CMC) and chitosan (Chit)) by using glucose as reducing agent, is presented. X-ray diffraction analyses of polysaccharides coated with AgNPs showed the formation of silver particle sizes in the range of 3.7-5.6 nm and have almost spherical shape. The entire prepared composite shows antimicrobial effect. The antibacterial activity of polysaccharides loaded with silver nanoparticles was evaluated against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. The results suggest excellent antibacterial activity. PMID:25817678

  14. The concentration effect of capping agent for synthesis of silver nanowire by using the polyol method

    SciTech Connect

    Lin, Jian-Yang [Department of Electronic Engineering, National Yunlin University of Science and Technology, Yunlin 640, Taiwan, ROC (China); Hsueh, Yu-Lee [Graduate School of Engineering Science and Technology, National Yunlin University of Science and Technology, Yunlin 640, Taiwan, ROC (China); Huang, Jung-Jie, E-mail: jjhuang@mdu.edu.tw [Department of Materials Science and Engineering, MingDao University, Chunghua 523, Taiwan, ROC (China)

    2014-06-01

    Silver nanowires were synthesized by the polyol method employing ethylene glycol, Poly(N-vinylpyrrolidone) (PVP) and silver nitrate (AgNO{sub 3}) as the precursors. Most of the studies used metal salts (PtCl{sub 2}, NaCl) as seed precursor to synthesize the silver nanowires. In the study, the metal salts were not used and the concentration of capping agent was changed to observe the aspect ratio of silver nanowires. The experimental results showed that controlling synthesis temperature, Poly(N-vinylpyrrolidone) (PVP) molecular weight, reactant concentrations, and addition rates of AgNO{sub 3} affects the growth characteristics of silver nanowires. Field-emission scanning electron microscopy, UV–vis spectrophotometry, and X-ray diffractometry were employed to characterize the silver nanowires. As increasing the concentration of PVP, the silver nanowire diameter widened and resulted in a smaller aspect ratio. We successfully prepared silver nanowires (diameter: 170 nm, length: 20 ?m). The silver nanowire thin film suspension showed high transmittance, low sheet resistance, and may be used for transparent conductive film applications. - Graphical abstract: The FE-SEM image shows that nanostructures with considerable quantities of silver nanowires can also be produced when the PVP (Mw=360 K)/AgNO{sub 3} molar ratio was 2.5. - Highlights: • The polyol method was used to synthesize of silver nanowire. • The metal seed precursors were not used before synthesizing the silver nanowires. • The silver nanowire diameter and length was 170 nm and 20 ?m, respectively. • Silver nanowire film with high transmittance (>85%) and low sheet resistance (<110 ?/sq)

  15. Synthesis of stabilized myrrh-capped hydrocolloidal magnetite nanoparticles.

    PubMed

    Atta, Ayman M; Al-Lohedan, Hamad A; Al-Hussain, Sami A

    2014-01-01

    Herein we report a new method for synthesizing stabilized magnetic nanoparticle (MNP) colloids. A new class of monodisperse water-soluble magnetite nano-particles was prepared by a simple and inexpensive co-precipitation method. Iron ions and iodine were prepared by the reaction between ferric chloride and potassium iodide. The ferrous and ferric ions were hydrolyzed at low temperature at pH 9 in the presence of iodine to produce iron oxide nanoparticles. The natural product myrrh gum was used as capping agent to produce highly dispersed coated magnetite nanoparticles. The structure and morphology of the magnetic nanogel was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM), and X-ray diffraction (XRD) was used to examine the crystal structure of the produced magnetite nanoparticles. PMID:25090117

  16. Molecular mechanisms of toxicity of silver nanoparticles in zebrafish embryos.

    PubMed

    van Aerle, Ronny; Lange, Anke; Moorhouse, Alex; Paszkiewicz, Konrad; Ball, Katie; Johnston, Blair D; de-Bastos, Eliane; Booth, Timothy; Tyler, Charles R; Santos, Eduarda M

    2013-07-16

    Silver nanoparticles cause toxicity in exposed organisms and are an environmental health concern. The mechanisms of silver nanoparticle toxicity, however, remain unclear. We examined the effects of exposure to silver in nano-, bulk-, and ionic forms on zebrafish embryos (Danio rerio) using a Next Generation Sequencing approach in an Illumina platform (High-Throughput SuperSAGE). Significant alterations in gene expression were found for all treatments and many of the gene pathways affected, most notably those associated with oxidative phosphorylation and protein synthesis, overlapped strongly between the three treatments indicating similar mechanisms of toxicity for the three forms of silver studied. Changes in oxidative phosphorylation indicated a down-regulation of this pathway at 24 h of exposure, but with a recovery at 48 h. This finding was consistent with a dose-dependent decrease in oxygen consumption at 24 h, but not at 48 h, following exposure to silver ions. Overall, our data provide support for the hypothesis that the toxicity caused by silver nanoparticles is principally associated with bioavailable silver ions in exposed zebrafish embryos. These findings are important in the evaluation of the risk that silver particles may pose to exposed vertebrate organisms. PMID:23758687

  17. Molecular Mechanisms of Toxicity of Silver Nanoparticles in Zebrafish Embryos

    PubMed Central

    2013-01-01

    Silver nanoparticles cause toxicity in exposed organisms and are an environmental health concern. The mechanisms of silver nanoparticle toxicity, however, remain unclear. We examined the effects of exposure to silver in nano-, bulk-, and ionic forms on zebrafish embryos (Danio rerio) using a Next Generation Sequencing approach in an Illumina platform (High-Throughput SuperSAGE). Significant alterations in gene expression were found for all treatments and many of the gene pathways affected, most notably those associated with oxidative phosphorylation and protein synthesis, overlapped strongly between the three treatments indicating similar mechanisms of toxicity for the three forms of silver studied. Changes in oxidative phosphorylation indicated a down-regulation of this pathway at 24 h of exposure, but with a recovery at 48 h. This finding was consistent with a dose-dependent decrease in oxygen consumption at 24 h, but not at 48 h, following exposure to silver ions. Overall, our data provide support for the hypothesis that the toxicity caused by silver nanoparticles is principally associated with bioavailable silver ions in exposed zebrafish embryos. These findings are important in the evaluation of the risk that silver particles may pose to exposed vertebrate organisms. PMID:23758687

  18. Applications and toxicity of silver nanoparticles: a recent review.

    PubMed

    Marin, Stefania; Vlasceanu, George Mihail; Tiplea, Roxana Elena; Bucur, Ioana Raluca; Lemnaru, Madalina; Marin, Maria Minodora; Grumezescu, Alexandru Mihai

    2015-05-27

    Silver nanoparticles (AgNPs) exhibit a consistent amount of flexible properties which endorse them for a larger spectrum of applications in biomedicine and related fields. Over the years, silver nanoparticles have been subjected to numerous in vitro and in vivo tests to provide information about their toxic behavior towards living tissues and organisms. Researchers showed that AgNPs have high antimicrobial efficacy against many bacteria species including Escherichia coli, Neisseria gonorrhea, Chlamydia trachomatis and also viruses. Due to their novel properties, the incorporation of silver nanoparticles into different materials like textile fibers and wound dressings can extend their utility on the biomedical field while inhibiting infections and biofilm development. Among the noble metal nanoparticles, AgNPs present a series of features like simple synthesis routes, adequate and tunable morphology, and high surface to volume ratio, intracellular delivery system, a large plasmon field area recommending them as ideal biosensors, catalysts or photo-controlled delivery systems. In bioengineering, silver nanoparticles are considered potentially ideal gene delivery systems for tissue regeneration. The remote triggered detection and release of bioactive compounds of silver nanoparticles has proved their relevance also in forensic sciences. The authors report an up to date review related to the toxicity of AgNPs and their applications in antimicrobial activity and biosensors for gene therapy. PMID:25877089

  19. Size-dependent structure of silver nanoparticles under high pressure

    SciTech Connect

    Koski, Kristie Jo

    2008-12-31

    Silver noble metal nanoparticles that are<10 nm often possess multiply twinned grains allowing them to adopt shapes and atomic structures not observed in bulk materials. The properties exhibited by particles with multiply twinned polycrystalline structures are often far different from those of single-crystalline particles and from the bulk. I will present experimental evidence that silver nanoparticles<10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. Results for nanoparticles in the intermediate size range of 5 to 10 nm suggest a reversible linear pressure-dependent rhombohedral distortion which has not been previously observed in bulk silver. I propose a mechanism for this transitiion that considers the bond-length distribution in idealized multiply twinned icosahedral particles. Results for nanoparticles of 3.9 nm suggest a reversible linear pressure-dependent orthorhombic distortion. This distortion is interpreted in the context of idealized decahedral particles. In addition, given these size-dependent measurements of silver nanoparticle compression with pressure, we have constructed a pressure calibration curve. Encapsulating these silver nanoparticles in hollow metal oxide nanospheres then allows us to measure the pressure inside a nanoshell using x-ray diffraction. We demonstrate the measurement of pressure gradients across nanoshells and show that these nanoshells have maximum resolved shear strengths on the order of 500 MPa to IGPa.

  20. Green synthesis of colloid silver nanoparticles and resulting biodegradable starch/silver nanocomposites.

    PubMed

    Cheviron, Perrine; Gouanvé, Fabrice; Espuche, Eliane

    2014-08-01

    Environmentally friendly silver nanocomposite films were prepared by an ex situ method consisting firstly in the preparation of colloidal silver dispersions and secondly in the dispersion of the as-prepared nanoparticles in a potato starch/glycerol matrix, keeping a green chemistry process all along the synthesis steps. In the first step concerned with the preparation of the colloidal silver dispersions, water, glucose and soluble starch were used as solvent, reducing agent and stabilizing agent, respectively. The influences of the glucose amount and reaction time were investigated on the size and size distribution of the silver nanoparticles. Two distinct silver nanoparticle populations in size (diameter around 5 nm size for the first one and from 20 to 50 nm for the second one) were distinguished and still highlighted in the potato starch/glycerol based nanocomposite films. It was remarkable that lower nanoparticle mean sizes were evidenced by both TEM and UV-vis analyses in the nanocomposites in comparison to the respective colloidal silver dispersions. A dispersion mechanism based on the potential interactions developed between the nanoparticles and the polymer matrix and on the polymer chain lengths was proposed to explain this morphology. These nanocomposite film series can be viewed as a promising candidate for many applications in antimicrobial packaging, biomedicines and sensors. PMID:24751276

  1. Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction.

    PubMed

    Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi

    2015-06-01

    The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO3 aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20-30nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. PMID:25842144

  2. New paradigm shift for the green synthesis of antibacterial silver nanoparticles utilizing plant extracts.

    PubMed

    Park, Youmie

    2014-09-01

    This review covers general information regarding the green synthesis of antibacterial silver nanoparticles. Owing to their antibacterial properties, silver nanoparticles are widely used in many areas, especially biomedical applications. In green synthesis practices, the chemical reducing agents are eliminated, and biological entities are utilized to convert silver ions to silver nanoparticles. Among the various biological entities, natural plant extracts have emerged as green reducing agents, providing eco-friendly routes for the preparation of silver nanomaterials. The most obvious merits of green synthesis are the increased biocompatibility of the resulting silver nanoparticles and the ease with which the reaction can be carried out. This review summarizes some of the plant extracts that are used to produce antibacterial silver nanoparticles. Additionally, background information regarding the green synthesis and antibacterial activity of silver nanoparticles is provided. Finally, the toxicological aspects of silver nanoparticles are briefly mentioned. PMID:25343010

  3. [Antimicrobial activity of stable silver nanoparticles of a certain size].

    PubMed

    Mukha, Iu P; Eremenko, A M; Smirnova, N P; Mikhienkova, A I; Korchak, G I; Gorchev, V F; Chunikhin, A Iu

    2013-01-01

    Conditions for obtaining stable silver nanoparticles smaller than 10 nm were developed using a binary stabilizer polyvinylpyrrolidone/sodium dodecylsulphate in optimal ratio. Optical spectra, morphology and dependence of size of the nanoparticles on the amount of reducing agent were studied. Colloidal solutions of nanosilver showed a high bactericidal activity against strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and fungicidal activity against Candida albicans. The mechanism of action of nanosized silver on microbial cell was examined by laser scanning confocal microscope using fluorescent label. First step of antimicrobial effect on microorganisms was membrane damage and penetration of silver nanoparticles into the cell. Prolonged stability of nanoparticles and their antimicrobial activity over the past two years were showed. PMID:23795483

  4. Interaction of silver nanoparticles with tethered bilayer lipid membranes.

    PubMed

    Goreham, Renee V; Thompson, Vanessa C; Samura, Yuya; Gibson, Christopher T; Shapter, Joseph G; Köper, Ingo

    2015-06-01

    Silver nanoparticles are well-known for their antibacterial properties. However, the detailed mechanism describing the interaction between the nanoparticles and a cell membrane is not fully understood, which can impede the use of the particles in biomedical applications. Here, a tethered bilayer lipid membrane has been used as a model system to mimic a natural membrane and to study the effect of exposure to small silver nanoparticles with diameters of about 2 nm. The solid supported membrane architecture allowed for the application of surface analytical techniques such as electrochemical impedance spectroscopy and atomic force microscopy. Exposure of the membrane to solutions of the silver nanoparticles led to a small but completely reversible perturbation of the lipid bilayer. PMID:25950498

  5. Synthesis and antibacterial activity of of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Maliszewska, I.; Sadowski, Z.

    2009-01-01

    Silver nanoparticles have been known to have inhibitory and bactericidal effects but the antimicrobial mechanism have not been clearly revealed. Here, we report on the synthesis of metallic nanoparticles of silver using wild strains of Penicillium isolated from environment. Kinetics of the formation of nanosilver was monitored using the UV-Vis. TEM micrographs showed the formation of silver nanoparticles in the range 10-100 nm. Obtained Ag nanoparticles were evaluated for their antimicrobial activity against the gram-positive and gram-negative bacteria. As results, Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were effectively inhibited. Nanosilver is a promising candidate for development of future antibacterial therapies because of its wide spectrum of activity.

  6. Antibacterial activity of silver nanoparticles synthesized from serine.

    PubMed

    Jayaprakash, N; Judith Vijaya, J; John Kennedy, L; Priadharsini, K; Palani, P

    2015-04-01

    Silver nanoparticles (Ag NPs) were synthesized by a simple microwave irradiation method using polyvinyl pyrrolidone (PVP) as a capping agent and serine as a reducing agent. UV-Visible spectra were used to confirm the formation of Ag NPs by observing the surface plasmon resonance (SPR) band at 443nm. The emission spectrum of Ag NPs showed an emission band at 484nm. In the presence of microwave radiation, serine acts as a reducing agent, which was confirmed by Fourier transformed infrared (FT-IR) spectrum. High-resolution transmission electron microscopy (HR-TEM) and high-resolution scanning electron microscopy (HR-SEM) were used to investigate the morphology of the synthesized sample. These images showed the sphere-like morphology. The elemental composition of the sample was determined by the energy dispersive X-ray analysis (EDX). Selected area electron diffraction (SAED) was used to find the crystalline nature of the Ag NPs. The electrochemical behavior of the synthesized Ag NPs was analyzed by the cyclic voltammetry (CV). Antibacterial experiments showed that the prepared Ag NPs showed relatively similar antibacterial activities, when compared with AgNO3 against Gram-positive and Gram-negative bacteria. PMID:25686955

  7. Silver nanoparticles: correlating nanoparticle size and cellular uptake with genotoxicity.

    PubMed

    Butler, Kimberly S; Peeler, David J; Casey, Brendan J; Dair, Benita J; Elespuru, Rosalie K

    2015-07-01

    The focus of this research was to develop a better understanding of the pertinent physico-chemical properties of silver nanoparticles (AgNPs) that affect genotoxicity, specifically how cellular uptake influences a genotoxic cell response. The genotoxicity of AgNPs was assessed for three potential mechanisms: mutagenicity, clastogenicity and DNA strand-break-based DNA damage. Mutagenicity (reverse mutation assay) was assessed in five bacterial strains of Salmonella typhimurium and Echerichia coli, including TA102 that is sensitive to oxidative DNA damage. AgNPs of all sizes tested (10, 20, 50 and 100nm), along with silver nitrate (AgNO3), were negative for mutagenicity in bacteria. No AgNPs could be identified within the bacteria cells using transmission electron microscopy (TEM), indicating these bacteria lack the ability to actively uptake AgNPs 10nm or larger. Clastogenicity (flow cytometry-based micronucleus assay) and intermediate DNA damage (DNA strand breaks as measured in the Comet assay) were assessed in two mammalian white blood cell lines: Jurkat Clone E6-1 and THP-1. It was observed that micronucleus and Comet assay end points were inversely correlated with AgNP size, with smaller NPs inducing a more genotoxic response. TEM results indicated that AgNPs were confined within intracellular vesicles of mammalian cells and did not penetrate the nucleus. The genotoxicity test results and the effect of AgNO3 controls suggest that silver ions may be the primary, and perhaps only, cause of genotoxicity. Furthermore, since AgNO3 was not mutagenic in the gram-negative bacterial Ames strains tested, the lack of bacterial uptake of the AgNPs may not be the major reason for the lack of genotoxicity observed. PMID:25964273

  8. Contributions of the nanoparticles and glass frit to conductivity in Pb-free silver paste

    Microsoft Academic Search

    Sung Hyun Park; Dong Seok Seo; Gwon Seung Yang; Jong Kook Lee

    2007-01-01

    Pb-free silver paste for low sintering temperature was prepared by mixing of two commercial silver powders (0.8 mum and 1.6 mum in size) and nanoparticles (30-50 nm in size). The silver nanoparticles were synthesized by a chemical reduction method using surfactant. To prepare Pb-free silver paste, 10 wt% and 20 wt% of the silver nanoparticles as sintering aids were added

  9. Nanoparticle Silver Catalysts That Show Enhanced Activity for Carbon Dioxide Electrolysis

    E-print Network

    Kenis, Paul J. A.

    Nanoparticle Silver Catalysts That Show Enhanced Activity for Carbon Dioxide Electrolysis Amin is about 10 times higher on 5 nm silver nanoparticles than on bulk silver even though measurements of two catalysts, a silver metal and ionic liquid 1- ethyl-3-methylimidazolium tetrafluoroborate (EMIM

  10. Amino acid mediated synthesis of silver nanoparticles and preparation of antimicrobial agar/silver nanoparticles composite films.

    PubMed

    Shankar, Shiv; Rhim, Jong-Whan

    2015-10-01

    Silver nanoparticles (AgNPs) were synthesized using amino acids (tyrosine and tryptophan) as reducing and capping agents, and they were incorporated into the agar to prepare antimicrobial composite films. The AgNPs solutions exhibited characteristic absorption peak at 420nm that showed a red shift to ?434nm after forming composite with agar. XRD data demonstrated the crystalline structure of AgNPs with dominant (111) facet. Apparent surface color and transmittance of agar films were greatly influenced by the AgNPs. The incorporation of AgNPs into agar did not exhibit any change in chemical structure, thermal stability, moisture content, and water vapor permeability. The water contact angle, tensile strength, and modulus decreased slightly, but elongation at break increased after AgNPs incorporation. The agar/AgNPs nanocomposite films possessed strong antibacterial activity against Listeria monocytogenes and Escherichia coli. The agar/AgNPs film could be applied to the active food packaging by controlling the food-borne pathogens. PMID:26076636

  11. Green Synthesis of Small Silver Nanoparticles Using Geraniol and Its Cytotoxicity against Fibrosarcoma-Wehi 164

    Microsoft Academic Search

    Mona Safaepour; Ahmad Reza Shahverdi; Hamid Reza Shahverdi; Mohammad Reza Khorramizadeh; Ahmad Reza Gohari; Ahmad-Reza Shahverdi

    Many reports have been published about the biogenesis of silver nanoparticles using several plant extracts such as Pelargonium graveolens (P.graveolens- geranium) and Azadirachta indica (neem) but the capacity of their natural reducing constituents to form silver nanoparticles has not yet been studied. In this research the synthesis of silver nanoparticles using geraniol has been investigated. We successfully synthesized uniformly dispersed

  12. Trapping and release of citrate-capped gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Reyes, Darwin R.; Mijares, Geraldine I.; Nablo, Brian; Briggman, Kimberly A.; Gaitan, Michael

    2011-08-01

    An electrical method to trap and release charged gold nanoparticles onto and from the surface of gold electrodes modified by an alkanethiol self-assembled monolayer (SAM) is presented. To form electrodes coated with gold nanoparticles (GNPs), amine-terminated SAMs on gold electrodes were immersed in a solution of negatively charged citrate-capped GNPs. Accumulation of GNPs on the electrode surface was monitored by a decrease in the impedance of the SAM-modified electrode and by an increase in the electrochemical activity at the electrode as shown through cyclic voltammetry (CV). Electrostatic interactions between the GNPs and the amine-terminated SAM trap the GNPs on the electrode surface. Application of a subsequent negative bias to the electrode initiated a partial release of the GNPs from the electrode surface. Impedance spectroscopy, cyclic voltammetry, ultraviolet-visible (UV-Vis) spectroscopy and atomic force microscopy (AFM) were used to monitor and confirm the attraction of GNPs to and release from the aminealkanethiolated gold electrodes. This work describes a method of trapping and release for citrate-capped GNPs that could be used for on-demand nanoparticle delivery applications such as in assessing and modeling nanoparticle toxicology, as well as for monitoring the functionalization of gold nanoparticles.

  13. Investigation of passivated silver nanoparticles Shengtai He a

    E-print Network

    Gao, Hongjun

    . Introduction Nanometer size crystals, nanocrystals (NCs), display many properties, which are both quanti at nanometer-scale and obtain the ordered 2D or 3D structure, capped organic molecules such as al- kylthiol microscopy (TEM) copper grids. Then, the formation of the 1-nonanethiol protected silver 27 July 2001

  14. Silver nanoparticle-based ultrasensitive chemiluminescent detection of DNA hybridization and single-nucleotide polymorphisms.

    PubMed

    Liu, Cheng-Hui; Li, Zheng-Ping; Du, Bao-An; Duan, Xin-Rui; Wang, Yu-Cong

    2006-06-01

    A new nanoparticle-based chemiluminescent (CL) method has been developed for the ultrasensitive detection of DNA hybridization. The assay relies on a sandwich-type DNA hybridization in which the DNA targets are first hybridized to the captured oligonucleotide probes immobilized on polystyrene microwells and then the silver nanoparticles modified with alkylthiol-capped oligonucleotides are used as probes to monitor the presence of the specific target DNA. After being anchored on the hybrids, silver nanoparticles are dissolved to Ag+ in HNO3 solution and sensitively determined by a coupling CL reaction system (Ag+-Mn2+-K2S2O8-H3PO4-luminol). The combination of the remarkable sensitivity of the CL method with the large number of Ag+ released from each hybrid allows the detection of specific sequence DNA targets at levels as low as 5 fM. The sensitivity increases 6 orders of magnitude greater than that of the gold nanoparticle-based colorimetric method and is comparable to that of surface-enhanced Raman spectroscopy, which is one of the most sensitive detection approaches available to the nanoparticle-based detection for DNA hybridization. Moreover, the perfectly complementary DNA targets and the single-base mismatched DNA strands can be evidently differentiated through controlling the temperature, which indicates that the proposed CL assay offers great promise for single-nucleotide polymorphism analysis. PMID:16737231

  15. Green biosynthesis of silver nanoparticles using Curcuma longa tuber powder

    PubMed Central

    Shameli, Kamyar; Ahmad, Mansor Bin; Zamanian, Ali; Sangpour, Parvanh; Shabanzadeh, Parvaneh; Abdollahi, Yadollah; Zargar, Mohsen

    2012-01-01

    Green synthesis of noble metal nanoparticles is a vastly developing area of research. Metallic nanoparticles have received great attention from chemists, physicists, biologists, and engineers who wish to use them for the development of a new-generation of nanodevices. In this study, silver nanoparticles were biosynthesized from aqueous silver nitrate through a simple and eco-friendly route using Curcuma longa tuber-powder extracts, which acted as a reductant and stabilizer simultaneously. Characterizations of nanoparticles were done using different methods, which included ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier-transform infrared spectroscopy. The ultraviolet-visible spectrum of the aqueous medium containing silver nanoparticles showed an absorption peak at around 415 nm. Transmission electron microscopy showed that mean diameter and standard deviation for the formation of silver nanoparticles was 6.30 ± 2.64 nm. Powder X-ray diffraction showed that the particles are crystalline in nature, with a face-centered cubic structure. The most needed outcome of this work will be the development of value-added products from C. longa for biomedical and nanotechnology-based industries. PMID:23341739

  16. Influence of temperature and precursor concentration on the synthesis of HDA-capped Ag{sub 2}Se nanoparticles

    SciTech Connect

    Mlambo, M. [Department of Chemistry, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900 (South Africa); Molecular Science Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, Wits 2050 (South Africa); Moloto, M.J., E-mail: makwenam@vut.ac.za [Department of Chemistry, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900 (South Africa); Moloto, N. [Molecular Science Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, Wits 2050 (South Africa); Mdluli, P.S. [Nanotechnology Innovation Centre, Advanced Materials Division, Mintek, Private Bag X3015, Randburg 2125 (South Africa)

    2013-06-01

    Graphical abstract: The temperature effect on the growth and size of silver selenide nanoparticles with the size distribution and XRD patterns. Highlights: ? The HDA-capped Ag{sub 2}Se nanoparticles were synthesized via the colloidal route. ? Temperature and monomer concentration of the reaction were varied. ? The concentration as a factor influenced particles with a decrease observed as the amount of Ag{sup +} ion source is increased. ? Temperature has expected influence on the growth of particles resulting in increase as the temperature is increased. ? TEM images shows spherical particles and their orthorhombic phase from structural analysis by XRD. - Abstract: The size dependent of temperature and precursor concentration on the synthesis of hexadecylamine capped Ag{sub 2}Se nanoparticles via the colloidal route were studied using the combination of optical and structural analysis. The as-prepared Ag{sub 2}Se nanoparticles showed the quantum confinement with all the obtained absorption band edges blue-shifted from the bulk and their corresponding emission maxima displaying a red-shift from band edges characterised by UV–vis absorption and photoluminescence spectroscopy. The particle sizes were obtained from transmission electron microscopy analysis. The increase in precursor concentration resulted in a decrease in nanoparticle sizes. The increase in reaction temperature showed an increase in the nanoparticle sizes, when the critical temperature at 160 °C was reached, the nanoparticle sizes decreased.

  17. Preparation of starch-stabilized silver nanoparticles from amylose-sodium palmitate inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-stabilized silver nanoparticles were prepared from amylose-sodium palmitate complexes by first converting sodium palmitate to silver palmitate by reaction with silver nitrate and then reducing the silver ion to metallic silver. This process produced water solutions that could be dried and the...

  18. Sulfidation of Silver Nanoparticles: Natural antidote to their toxicity

    PubMed Central

    Levard, Clément; Hotze, Ernest M.; Colman, Benjamin P.; Truong, Lisa; Yang, X. Y.; Bone, Audrey; Brown, Gordon E.; Tanguay, Robert L.; Di Giulio, Richard T.; Bernhardt, Emily S.; Meyer, Joel N.; Wiesner, Mark R.; Lowry, Gregory V.

    2014-01-01

    Nanomaterials are highly dynamic in biological and environmental media. A critical need for advancing environmental health and safety research for nanomaterials is to identify commonly occurring physical and chemical transformations affecting nanomaterial properties and toxicity. Silver nanoparticles, one of the most ecotoxic and well-studied nanomaterials, readily sulfidize in the environment. Here, we show that very low degrees of sulfidation (0.019 S/Ag mass ratio) universally and significantly decreases the toxicity of silver nanoparticles to four diverse types of aquatic and terrestrial eukaryotic organisms. Toxicity reduction is primarily associated with a decrease in Ag+ availability after sulfidation due to the lower solubility of Ag2S relative to elemental Ag (Ag(0)). We also show that chloride in exposure media determines silver nanoparticle toxicity by controlling the speciation of Ag. These results highlight the need to consider environmental transformation of NPs in assessing their toxicity to accurately portray their potential environmental risks. PMID:24180218

  19. In situ synthesis of silver nano-particles in polymethylmethacrylate

    Microsoft Academic Search

    Narendra Singh; P. K. Khanna

    2007-01-01

    One-step in situ preparation of silver nano-particles in polymethylmethacrylate (PMMA) using N,N?-dimethylformamide (DMF) as a medium has been performed successfully. The radical polymerization of methaycrylic acid (MMA), in presence of benzoyl peroxide followed by reaction of silver source has been successfully employed to synthesize Ag\\/PMMA nano-composite. A light yellow solution in its UV–Vis absorption spectrum showed surface plasmon resonance absorption

  20. Biocide silver nanoparticles in two different silica-based coating

    NASA Astrophysics Data System (ADS)

    Babapour, A.; Yang, B.; Bahang, S.; Cao, W.

    2012-09-01

    Silica-based coatings containing biocide silver nanoparticles have been synthesized using low temperature sol-gel method. Two different silane based matrices, phenyltriethoxysilane (PhTEOS) and tetraethyl orthosilicate (TEOS), were selected as precursor to prepare silica-based film. The films were analyzed by using UV-visible spectrophotometry, atomic force microscopy (AFM) and scanning electron microscopy (SEM) for their optical, surface morphological as well as structural properties. Optical properties of nanosilver in these two matrices showed that the peak absorption observed at different wavelength, which is due to the fact that optical absorption of nanoparticles is affected by the surrounding medium. It is also found that the silver absorption has higher intensity in PhTEOS than in TEOS matrix, indicating higher concentration of silver nanoparticles being loaded into the coating. To study silver release property, the films were immersed in water for 12 and 20 days. AFM and SEM analyzes present that higher concentration of silver nanoparticles and smaller particle sizes were synthesis in PhTEOS coating and consequently, more particles remains on the surfaces after 20 days which leads to longer antibacterial activity of PhTEOS coating.

  1. Organic electroluminescent devices using quantum-size silver nanoparticles

    Microsoft Academic Search

    Jin-Woo Park; Sung Soo Park; Chang-Sik Ha

    2007-01-01

    Nanocomposite layers consisting of poly(3,4,-ethylene dioxythiophene)\\/polystyrene sulfonic acid (PEDOT\\/PSS) and o-phenylenediamine\\u000a encapsulated quantum-size silver nanoparticles were investigated as a hole injection layer in the organic light emitting devices\\u000a (OLEDs) based on N,N?-diphenyl-N,N?-bis(3-methylphenyl)-1,1-biphenyl-4,4?-diamine) (TPD) as a hole transporting layer and tris(8-hydroxyquinolinato)aluminum\\u000a (Alq3) as an electron transporting and emitting layer. It was found that the addition of the silver nanoparticles (3?6 nm)\\u000a improved

  2. An insight into silver nanoparticles bioavailability in rats.

    PubMed

    Jiménez-Lamana, Javier; Laborda, Francisco; Bolea, Eduardo; Abad-Álvaro, Isabel; Castillo, Juan R; Bianga, Juliusz; He, Man; Bierla, Katarzyna; Mounicou, Sandra; Ouerdane, Laurent; Gaillet, Sylvie; Rouanet, Jean-Max; Szpunar, Joanna

    2014-12-01

    A comprehensive study of the bioavailability of orally administered silver nanoparticles (AgNPs) was carried out using a rat model. The silver uptake was monitored in liver and kidney tissues, as well as in urine and in feces. Significant accumulation of silver was found in both organs, the liver being the principal target of AgNPs. A significant (?50%) fraction of silver was found in feces whereas the fraction excreted via urine was negligible (< 0.01%). Intact silver nanoparticles were found in feces by asymmetric flow field-flow fractionation (AsFlFFF) coupled with UV-Vis analysis. Laser ablation-ICP MS imaging showed that AgNPs were able to penetrate into the liver, in contrast to kidneys where they were retained in the cortex. Silver speciation analysis in cytosols from kidneys showed the metallothionein complex as the major species whereas in the liver the majority of silver was bound to high-molecular (70-25 kDa) proteins. These findings demonstrate the presence of Ag(i), released by the oxidation of AgNPs in the biological environment. PMID:25363792

  3. Synthesis of silver nanoparticles from Melia dubia leaf extract and their in vitro anticancer activity.

    PubMed

    Kathiravan, V; Ravi, S; Ashokkumar, S

    2014-09-15

    Silver nanoparticles have a significant role in the pharmaceutical science. Especially, silver nanoparticles synthesized by the plant extracts lead a significant role in biological activities such as antimicrobial, antioxidant and anticancer. Keeping this in mind, the present work investigation has been taken up with the synthesized silver nanoparticles using the plant extract of Melia dubia and it characterizes by using UV-visible, XRD and SEM-EDS. The effect of the silver nanoparticles on human breast cancer (KB) cell line has been tested. Silver nanoparticles showed remarkable cytotoxicity activity against KB cell line with evidence of high therapeutic index value are the results are discussed. PMID:24769382

  4. Synthesis of silver nanoparticles from Melia dubia leaf extract and their in vitro anticancer activity

    NASA Astrophysics Data System (ADS)

    Kathiravan, V.; Ravi, S.; Ashokkumar, S.

    2014-09-01

    Silver nanoparticles have a significant role in the pharmaceutical science. Especially, silver nanoparticles synthesized by the plant extracts lead a significant role in biological activities such as antimicrobial, antioxidant and anticancer. Keeping this in mind, the present work investigation has been taken up with the synthesized silver nanoparticles using the plant extract of Melia dubia and it characterizes by using UV-visible, XRD and SEM-EDS. The effect of the silver nanoparticles on human breast cancer (KB) cell line has been tested. Silver nanoparticles showed remarkable cytotoxicity activity against KB cell line with evidence of high therapeutic index value are the results are discussed.

  5. Synthesis and spectroscopic studies of stable aqueous dispersion of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    El-Shishtawy, Reda M.; Asiri, Abdullah M.; Al-Otaibi, Maha M.

    2011-09-01

    A facile approach for the synthesis of stable aqueous dispersion of silver nanoparticles (AgNPs) using glucose as the reducing agent in water/micelles system, in which cetyltrimethylammonium bromide (CTAB) was used as capping agent (stabilizer) is described. The evolution of plasmon band of AgNPs was monitored under different conditions such as (a) concentration of sodium hydroxide, (b) concentration of glucose, (c) concentration of silver nitrate (d) concentration of CTAB, and (e) reaction time. AgNPs were characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), fluorescence spectroscopy and FT-IR spectroscopy. The results revealed an easy and viable strategy for obtaining stable aqueous dispersion of AgNPs with well controlled shape and size below 30 nm in diameter.

  6. Low-Temperature Synthesis and Properties of Silver Nanoparticles Stabilised by Acrylic Polymers

    Microsoft Academic Search

    Boris M. Sergeev; Gleb B. Sergeev; Viktor A. Kasaikin; Ekaterina A. Litmanovich; Andrej N. Prusov

    2001-01-01

    A cryochemical synthesis of silver nanoparticles stablised by poly(2-dimethylaminoethyl methacrylate) has been performed. It has been shown that precursors which do not possess optical properties of colloidal silver are present in the freshly prepared organodispersion of silver in 2-(dimethylamino)ethyl methacrylate (DMAEMA) on the early stages of nanoparticle growth. Sols prepared with cryochemically synthesised silver nanoparticles in water, acetone, and toluene

  7. The antibacterial activity of ceramsite coated by silver nanoparticles in micropore.

    PubMed

    Qiu, Shan; Huang, Xu; Xu, Shanwen; Ma, Fang

    2015-05-01

    In the present study, ceramsite was combined with silver nanoparticles (AgNPs) to fabricate a new nanocomposite for water disinfection. The ceramsite was prepared by fly ash, straw ash, and cement. AgNPs were synthesized using polyvinylpyrrolidone (PVP) as the capping agent. The nanocomposite was prepared by self-aggregation of AgNPs on the surface of the ceramsite. AgNPs capped with PVP can form a thin film on the surface of micropore in ceramsite. The nanocomposite can inhibit bacteria growth and induce damage of the cell membrane of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Therefore, the nanocomposite is a new material which can be used for disinfection in drinking water. PMID:25820386

  8. Gold and silver nanoparticles from Trianthema decandra: synthesis, characterization, and antimicrobial properties

    PubMed Central

    Geethalakshmi, R; Sarada, DVL

    2012-01-01

    Background There is an increasing commercial demand for nanoparticles due to their wide applicability in various markets, including medicine, catalysis, electronics, chemistry, and energy. In this report, a simple and ecofriendly chemical reaction for the synthesis of gold and silver nanoparticles from Trianthema decandra (Aizoaceae) has been developed. Methods and results On treatment of aqueous solutions containing chloroauric acid or silver nitrate with root extract of T. decandra, stable gold or silver nanoparticles were rapidly formed. The kinetics of reduction of gold and silver ions during the reaction was analyzed by ultraviolet-visible spectroscopy. Field emission-scanning electron microscopy showed formation of gold nanoparticles in various shapes, including spherical, cubical, triangular, and hexagonal, while silver nanoparticles were spherical. The size of the gold nanoparticles was 33–65 nm and that of the silver nanoparticles was 36–74 nm. Energy dispersive x-ray and Fourier transform infrared spectroscopy confirmed the presence of metallic gold and metallic silver in the respective nanoparticles. The antimicrobial properties of the synthesized nanoparticles were analyzed using the Kirby-Bauer method. The results show varied susceptibility of microorganisms to the gold and silver nanoparticles. Conclusion It is believed that phytochemicals present in T. decandra extract reduce the silver and gold ions into metallic nanoparticles. This strategy reduces the cost of production and the environmental impact. The silver and gold nanoparticles formed showed strong activity against all microorganisms tested. PMID:23091381

  9. Interaction studies between biosynthesized silver nanoparticle with calf thymus DNA and cytotoxicity of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Roy, Swarup; Sadhukhan, Ratan; Ghosh, Utpal; Das, Tapan Kumar

    2015-04-01

    The interaction of calf thymus DNA (CTDNA) with silver nanoparticles (SNP) has been investigated following spectroscopic studies, analysis of melting temperature (Tm) curves and hydrodynamic measurement. In spectrophotometric titration and thermal denaturation studies of CTDNA it was found that SNP can form a complex with double-helical DNA and the increasing value of Tm also supported the same. The association constant of SNP with DNA from UV-Vis study was found to be 4.1 × 103 L/mol. The fluorescence emission spectra of intercalated ethidium bromide (EB) with increasing concentration of SNP represented a significant reduction of EB intensity and quenching of EB fluorescence. The results of circular dichroism (CD) suggested that SNP can change the conformation of DNA. From spectroscopic, hydrodynamic, and DNA melting studies, SNP has been found to be a DNA groove binder possessing partial intercalating property. Cell cytotoxicity of SNP was compared with that of normal silver salt solution on HeLa cells. Our results show that SNP has less cytotoxicity compared to its normal salt solution and good cell staining property.

  10. Dermal exposure potential from textiles that contain silver nanoparticles

    PubMed Central

    Stefaniak, Aleksandr B; Duling, Mathew G; Lawrence, Robert B; Thomas, Treye A; LeBouf, Ryan F; Wade, Eleanor E; Abbas Virji, M

    2014-01-01

    Background: Factors that influence exposure to silver particles from the use of textiles are not well understood. Objectives: The aim of this study was to evaluate the influence of product treatment and physiological factors on silver release from two textiles. Methods: Atomic and absorbance spectroscopy, electron microscopy, and dynamic light scattering (DLS) were applied to characterize the chemical and physical properties of the textiles and evaluate silver release in artificial sweat and saliva under varying physiological conditions. One textile had silver incorporated into fiber threads (masterbatch process) and the other had silver nanoparticles coated on fiber surfaces (finishing process). Results: Several complementary and confirmatory analytical techniques (spectroscopy, microscopy, etc.) were required to properly assess silver release. Silver released into artificial sweat or saliva was primarily in ionic form. In a simulated “use” and laundering experiment, the total cumulative amount of silver ion released was greater for the finishing process textile (0.51±0.04%) than the masterbatch process textile (0.21±0.01%); P<0.01. Conclusions: We found that the process (masterbatch vs finishing) used to treat textile fibers was a more influential exposure factor than physiological properties of artificial sweat or saliva. PMID:25000110

  11. Effects of Humic and Fulvic Acids on Silver Nanoparticle Stability, Dissolution, and Toxicity.

    PubMed

    Gunsolus, Ian L; Mousavi, Maral P S; Hussein, Kadir; Bühlmann, Philippe; Haynes, Christy L

    2015-07-01

    The colloidal stability of silver nanoparticles (AgNPs) in natural aquatic environments influences their transport and environmental persistence, while their dissolution to Ag(+) influences their toxicity to organisms. Here, we characterize the colloidal stability, dissolution behavior, and toxicity of two industrially relevant classes of AgNPs (i.e., AgNPs stabilized by citrate or polyvinylpyrrolidone) after exposure to natural organic matter (NOM, i.e., Suwannee River Humic and Fulvic Acid Standards and Pony Lake Fulvic Acid Reference). We show that NOM interaction with the nanoparticle surface depends on (i) the NOM's chemical composition, where sulfur- and nitrogen-rich NOM more significantly increases colloidal stability, and (ii) the affinity of the capping agent for the AgNP surface, where nanoparticles with loosely bound capping agents are more effectively stabilized by NOM. Adsorption of NOM is shown to have little effect on AgNP dissolution under most experimental conditions, the exception being when the NOM is rich in sulfur and nitrogen. Similarly, the toxicity of AgNPs to a bacterial model (Shewanella oneidensis MR-1) decreases most significantly in the presence of sulfur- and nitrogen-rich NOM. Our data suggest that the rate of AgNP aggregation and dissolution in aquatic environments containing NOM will depend on the chemical composition of the NOM, and that the toxicity of AgNPs to aquatic microorganisms is controlled primarily by the extent of nanoparticle dissolution. PMID:26047330

  12. Biosynthesis of silver nanoparticles using Plectranthus amboinicus leaf extract and its antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Ajitha, B.; Ashok Kumar Reddy, Y.; Sreedhara Reddy, P.

    2014-07-01

    This study reports the simple green synthesis method for the preparation of silver nanoparticles (Ag NPs) using Plectranthus amboinicus leaf extract. The pathway of nanoparticles formation is by means of reduction of AgNO3 by leaf extract, which acts as both reducing and capping agents. Synthesized Ag NPs were subjected to different characterizations for studying the structural, chemical, morphological, optical and antimicrobial properties. The bright circular fringes in SAED pattern and diffraction peaks in XRD profile reveals high crystalline nature of biosynthesized Ag NPs. Morphological studies shows the formation of nearly spherical nanoparticles. FTIR spectrum confirms the existence of various functional groups of biomolecules capping the nanoparticles. UV-visible spectrum displays single SPR band at 428 nm indicating the absence of anisotropic particles. The synthesized Ag NPs exhibited better antimicrobial property towards gram negative Escherichia coli and towards tested Penicillium spp. than other tested microorganisms using disc diffusion method. Finally it has proven that the synthesized bio-inspired Ag NPs have potent antimicrobial effect.

  13. Electronic conductivity of alkyne-capped ruthenium nanoparticles.

    PubMed

    Kang, Xiongwu; Chen, Shaowei

    2012-07-21

    Ruthenium nanoparticles (2.12 ± 0.72 nm in diameter) were stabilized by the self-assembly of alkyne molecules (from 1-hexyne to 1-hexadecyne) onto the Ru surface by virtue of the formation of Ru-vinylidene interfacial linkages. Infrared measurements depicted three vibrational bands at 2050 cm(-1), 1980 cm(-1) and 1950 cm(-1), which were ascribed to the vibrational stretches of the terminal triple bonds that were bound onto the nanoparticle surface. Thermogravimetric analysis showed that there were about 65 to 96 alkyne ligands per nanoparticle (depending on the ligand chainlength), corresponding to a molecular footprint of 20 to 15 Å(2). This suggests that the ligands likely adopted a head-on configuration on the nanoparticle surface, consistent with a vinylidene bonding linkage due to interfacial tautomeric rearrangements. With this conjugated interfacial bonding interaction, electronic conductivity measurements of the corresponding nanoparticle solid films showed that the nanoparticles all exhibited linear current-potential curves within the potential range of -0.8 V to +0.8 V at varied temperatures (200 to 300 K). The ohmic characters were partly ascribed to the spilling of core electrons into the organic capping layer that facilitated interparticle charge transfer. Furthermore, based on the temperature dependence of the nanoparticle electronic conductivity, the activation energy for interparticle charge transfer was estimated to be in the range of 70 to 90 meV and significantly, the coupling coefficient (?) was found to be 0.31 Å(-1) for nanoparticles stabilized by short-chain alkynes (1-hexyne, 1-octyne, and 1-decyne), and 1.44 Å(-1) for those with long alkynes such as 1-dodecyne, 1-tetradecyne, and 1-hexadecyne. This may be accounted for by the relative contributions of the conjugated metal-ligand interfacial bonding interactions versus the saturated aliphatic backbones of the alkyne ligands to the control of interparticle charge transfer. PMID:22441806

  14. Adsorption mechanisms of RNA mononucleotides on silver nanoparticles.

    PubMed

    Miljani?, Snežana; Dijanoši?, Adriana; Mati?, Ivona

    2015-02-25

    Surface-enhanced Raman scattering (SERS) of four RNA mononucleotides (AMP, GMP, CMP and UMP) has been studied on the citrate-reduced silver colloid aggregated with sodium sulfate. Concentration dependent spectra in the range of 1×10(-7)-1×10(-4) mol dm(-3) were obtained, assigned and interpreted according to the surface selection rules. For purine mononucleotides, AMP and GMP, adsorption onto the silver nanoparticles through the six-membered ring of the nitrogenous base was suggested. Concentration dependent splitting of the ring breathing band in the spectra of AMP indicated coexistence of two species on the silver surface, which differed in contribution of the adenine N1 atom and the exocyclic NH2 group in binding. Unlike the AMP spectra, the spectra of GMP implied only one mode of adsorption of the molecules onto the silver nanoparticles, taking place through the guanine N1H and C=O group. Weak SERS spectra of pyrimidine mononucleotides, CMP and UMP, pointed to involvement of carbonyl oxygen in adsorption process, whereby the molecules adopted the position on the nanoparticles with ribose close to the metal surface. Intense bands in the low wavenumber region, associated with stretching of the formed Ag-N and/or Ag-O bonds, supported chemical binding of the RNA mononucleotides with the silver surface. PMID:25306131

  15. Electrochemical synthesis, characterisation and phytogenic properties of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Singaravelan, R.; Bangaru Sudarsan Alwar, S.

    2015-01-01

    This work exemplifies a simple and rapid method for the synthesis of silver nanodendrite with a novel electrochemical technique. The antibacterial activity of these silver nanoparticles (Ag NPs) against pathogenic bacteria was investigated along with the routine study of optical and spectral characterisation. The optical properties of the silver nanoparticles were characterised by diffuse reflectance spectroscopy. The optical band gap energy of the electrodeposited Ag NPs was determined from the diffuse reflectance using Kubelka-Munk formula. X-ray diffraction (XRD) studies were carried out to determine the crystalline nature of the silver nanoparticles which confirmed the formation of silver nanocrystals. The XRD pattern revealed that the electrodeposited Ag NPs were in the cubic geometry with dendrite preponderance. The average particle size and the peak broadening were deliberated using Debye-Scherrer equation and lattice strain due to the peak broadening was studied using Williamson-Hall method. Surface morphology of the Ag NPs was characterised by high-resolution scanning electron microscope and the results showed the high degree of aggregation in the particles. The antibacterial activity of the Ag NPs was evaluated and showed unprecedented level antibacterial activity against multidrug resistant strains such as Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia and Escherichia coli in combination with Streptomycin.

  16. The Speciation Of Silver Nanoparticles In Antimicrobial Fabric Before and After Exposure To A Hypochlorite/Detergent Solution

    EPA Science Inventory

    Because of their antibacterial properties, silver nanoparticles are often used in consumer products. To assess environmental and/or human health risks from these nanoparticles, there is a need to identify the chemical transformations that Silver nanoparticles undergo in differen...

  17. Magnetic properties of TOAB-capped CuO nanoparticles.

    NASA Astrophysics Data System (ADS)

    Seehra, M.; Punnoose, A.; Mahamuni, S.

    2002-03-01

    Synthesis of CuO nanoparticles (NP) capped with TOAB (tetraoctylammonium bromide) and their structural properties were reported recently [1]. Here we report on the magnetic properties of the TOAB-capped CuO-NP of size 4, 6 and 10 nm and compare these properties with those of uncapped CuO-NP in the size range of 6.6-37 nm described in the above abstract [2] and in a recent publication [3]. Temperature (5 K 350 K) and magnetic field (up to 55 kOe) variations of magnetization M, coercivity H_c, exchange bias He (field-cooled in 55 kOe) and the Neel temperature TN (where He goes to zero) were measured. The TOAB-capped NP have higher magnitudes of Ms (the weak ferromagnetic component of M) and lower He values, confirming the 1/Ms variation of He observed in uncapped CuO-NP for size < 16 nm. The reasons for the larger Ms in the capped vs. uncapped CuO-NP are now under investigation. TN decreases with the decrease in the particle size, as also observed for the uncapped CuO-NP. Supported in part by U.S. DOE (contract DE-FC26-99FT40540). [1]. K. Borgohain et al, Phys. Rev. B61, 11093 (2000). [2]. A. Punnoose and M. S. Seehra, preceding abstract. [3]. Punnoose, Magnone, Seehra & Bonevich, Phys. Rev. B64, 174420 (2001).

  18. Thermoluminescence of mercaptoethanol-capped ZnS:Mn nanoparticles.

    PubMed

    Sharma, Ravi; Bisen, D P

    2015-03-01

    The thermoluminescence (TL) of nanoparticles has become a matter of keen interest in recent times but is rarely reported. This article reports the synthesis of ZnS:Mn nanocrystals using a chemical route, with mercaptoethanol (ME) as the capping agent. The particle sizes for the nanocrystals were measured by X-ray diffraction (XRD) and also by studying transmission electron microscopy (TEM) patterns. The particle sizes of the synthesized samples were found to be between 1 and 3?nm. For samples with different concentrations of the capping agent, it was found that the TL intensity of the ZnS:Mn nanoparticles increased as the particle size decreased. A shift in the peak position of the TL glow curve was also seen with decreasing particle size. The TL intensity was found to be maximal for samples with 1.2% of Mn. A change in the peak position was not found for samples with different concentrations of Mn. The half-width glow peak curve method was used to determine the trap-depth. The frequency factor of the synthesized samples was also calculated. The stability of the charge carriers in the traps increases with decreasing nanoparticle size. The higher stability may be attributed to the higher surface/volume ratio and also to the increase in the trap-depth with decreasing particle size. PMID:24953864

  19. Light-driven transformation processes of anisotropic silver nanoparticles.

    PubMed

    Lee, George P; Shi, Yichao; Lavoie, Ellen; Daeneke, Torben; Reineck, Philipp; Cappel, Ute B; Huang, David M; Bach, Udo

    2013-07-23

    The photoinduced formation of silver nanoprisms from smaller silver seed particles in the presence of citrate anions is a classic example of a photomorphic reaction. In this case, light is used as a convenient tool to dynamically manipulate the shape of metal nanoparticles. To date, very little is known about the prevailing reaction mechanism of this type of photoreaction. Here we provide a detailed study of the shape transformation dynamics as a function of a range of different process parameters, such as photon energy and photon flux. For the first time, we provide direct evidence that the photochemical synthesis of silver nanoprisms from spherical seed nanoparticles proceeds via a light-activated two-dimensional coalescence mechanism. On the other hand, we could show that Ostwald ripening becomes the dominant reaction mechanism when larger silver nanoprisms are grown from photochemically synthesized smaller nanoprisms. This two-step reaction proceeds significantly faster and yields more uniform, sharper nanoprisms than the classical one-step photodevelopment process from seeds. The ability to dynamically control nanoparticle shapes and properties with light opens up novel synthesis avenues but also, more importantly, allows one to conceive new applications that exploit the nonstatic character of these nanoparticles and the ability to control and adjust their properties at will in a highly dynamic fashion. PMID:23730850

  20. Synthesis and Characterization of Silver Nanoparticles for an Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Orbaek, Alvin W.; McHale, Mary M.; Barron, Andrew R.

    2015-01-01

    The aim of this simple, quick, and safe laboratory exercise is to provide undergraduate students an introduction to nanotechnology using nanoparticle (NP) synthesis. Students are provided two procedures that allow for the synthesis of different yet controlled sizes of silver NPs. After preparing the NPs, the students perform UV-visible…

  1. Transparent conductive grids via direct writing of silver nanoparticle inks

    SciTech Connect

    Ahn, Bok Y; Lorang, David J; Lewis, Jennifer A

    2011-01-01

    Transparent conductive grids are patterned by direct writing of concentrated silver nanoparticle inks. This maskless, etch-free patterning approach is used to produce well-defined, two-dimensional periodic arrays composed of conductive features with center-to-center separation distances of up to 400 µm and an optical transmittance as high as 94.1%.

  2. Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms.

    EPA Science Inventory

    The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) coated silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) in marine organisms via marine sediment exposure was investigated. Results from 7-d sediment toxicity tests indicate that Ag...

  3. Monolayer-capped gold nanoparticles for disease detection from breath.

    PubMed

    Nakhleh, Morad K; Broza, Yoav Y; Haick, Hossam

    2014-09-01

    The recognition of volatile organic compounds in breath samples is a promising approach for noninvasive safe diagnosis of disease. Spectrometry and spectroscopy methods used for breath analysis suffer from suboptimal accuracy, are expensive and are unsuitable for diagnostics. This article presents a concise review on arrays of monolayer-capped gold nanoparticle (GNP) sensors in conjugation with pattern recognition methods for cost-effective, fast and high-throughput point-of-care diagnostic results from exhaled breath samples. The article starts with a general introduction to the rationale and advantages of breath analysis as well as with a presentation of the utility of monolayer-capped GNP sensors in this field. The article continues with a presentation of the main fabrication and operation principles of these GNP sensors and concludes with selected examples regarding their utility in different fields of medicine, particularly in neurology, infectiology, respiratory medicine and oncology. PMID:25343349

  4. Synthesis of silver nanoparticles using Sacha inchi (Plukenetia volubilis L.) leaf extracts

    PubMed Central

    Kumar, Brajesh; Smita, Kumari; Cumbal, Luis; Debut, Alexis

    2014-01-01

    Silver nanoparticles (AgNPs) are fabricated using Sacha inchi (SI) or (Plukenetia volubilis L.) leaf extract as non-toxic reducing agent with particle size ranging from 4 to 25 nm. Optical, structural and morphological properties of the synthesized nanoparticles have been characterized by using Visual, UV–Vis spectrophotometer, transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. Selected area electron diffraction (SAED) confirmed the formation of metallic Ag. Infrared spectrum measurement was carried out to hypothesize the possible phytochemicals responsible for stabilization and capping of the AgNPs. It shows the significant antioxidant efficacy in comparison with SI leaf extracts against 1,1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that green AgNPs could be used effectively in future engineering and medical concerns. PMID:25473370

  5. Green synthesis and characterization of silver nanoparticle using Aloe barbadensis

    NASA Astrophysics Data System (ADS)

    Thappily, Praveen; Shiju, K.

    2014-10-01

    Green synthesis of silver nanoparticles was achieved by simple visible light irradiation using aloe barbadensis leaf extract as reducing agent. UV-Vis spectroscopic analysis was used for confirmation of the successful formation of nanoparticles. Investigated the effect of light irradiation time on the light absorption of the nanoparticles. It is observed that upto 25 minutes of light irradiation, the absorption is linearly increasing with time and after that it becomes saturated. Finally, theoretically fitted the time-absorption graph and modeled a relation between them with the help of simulation software.

  6. Mycosynthesis of silver nanoparticles using Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W. Curt.:Fr.) P. Karst. and their role as antimicrobials and antibiotic activity enhancers.

    PubMed

    Karwa, A; Gaikwad, Swapnil; Rai, Mahendra K

    2011-01-01

    Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum, has been used over the ages as highly medicinal herb in the Orient. Many useful properties of this fungus are still being studied; we report here a new facet of this "elixir of life" as a mycosource for synthesis of metal nanoparticles. Treating the extracellular suspension filtrate of the mycelia of G. lucidum with silver nitrate reduces the metal ions to nanoparticles. Optical detection followed by confirmation through spectroscopic analysis suggests that this fungus can be used for the purpose of safe and sure synthesis of silver nanoparticles, demand for which is growing day by day in all fields of human life. LM-20 analysis of these G. lucidum-synthesised nanoparticles reveals the polydispersity and distribution of silver nanoparticles in the range of 10-70 nm with an average size of 45 nm and a concentration of 0.37 x 108 particles/mL. FT-IR spectrum confirms the stability of these nanoparticles due to presence of amide linkages and protein capping. These nanoparticles have shown strong bactericidal activity against test pathogens Staphylococcus aureus and Escherichia coli, and also exhibited their efficiency in enhancing the activity of the synthetic antibiotic tetracycline. The method of synthesising silver nanoparticles and its bactericidal effect discussed here can be used for environment-friendly and economically feasible production for different applications where chemically synthesized nanoparticles cause undesirable effects. PMID:22324414

  7. Plant-mediated biosynthesis of silver and gold nanoparticles.

    PubMed

    Dwivedi, Amarendra Dhar; Gopal, Krishna

    2011-02-01

    Single-pot biosynthesis of silver and gold quasi-spherical nanoparticles (SNPs and GNPs) in the size range of 10-30 nm was attempted using Chenopodium album (an obnoxious weed). This method is rapid, facile, convenient and environmentally safe. Average crystal size was approximately 12 nm and 10 nm for silver and gold nanocrystals respectively. Synthesized NPs were stable in a wide range of pH as there was less variation in zeta potential values. In synthesis of SNPs and GNPs, naturally occurring oxalic acid played significant role in bio-reduction of silver nitrate and auric acid solution into their corresponding silver and gold nano-colloids in single step rapid process. PMID:21485852

  8. Synthesis of silver nanoparticles with antibacterial activity using the lichen Parmotrema praesorediosum

    PubMed Central

    Mie, Ropisah; Samsudin, Mohd Wahid; Din, Laily B; Ahmad, Azizan; Ibrahim, Nazlina; Adnan, Siti Noor Adnalizawati

    2014-01-01

    Development of a green chemistry process for the synthesis of silver nanoparticles has become a focus of interest. This would offer numerous benefits, including ecofriendliness and compatibility for biomedical applications. Here we report the synthesis of silver nanoparticles from the reduction of silver nitrate and an aqueous extract of the lichen Parmotrema praesorediosum as a reductant as well as a stabilizer. The physical appearance of these silver nanoparticles was characterized using ultraviolet-visible spectroscopy, electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction techniques. The results show that silver nanoparticles synthesized using P. praesorediosum have an average particle size of 19 nm with a cubic structure. The antibacterial activity of the synthesized silver nanoparticles was tested against eight micro-organisms using the disk diffusion method. The results reveal that silver nanoparticles synthesized using P. praesorediosum have potential antibacterial activity against Gram-negative bacteria. PMID:24379670

  9. Capping and in vivo toxicity studies of gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Nghiem, Thi Ha Lien; Tuyen Nguyen, Thi; Fort, Emmanuel; Phuong Nguyen, Thanh; Nhung Hoang, Thi My; Quy Nguyen, Thi; Nhung Tran, Hong

    2012-03-01

    Water-dispersed colloidal gold nanoparticles (AuNPs) with high concentration were synthesized from metal precursor HAuCl4. The bovine serum albumin (BSA) and heterobiofunctionalized thiol polyethylene glycol acid (HS–PEG–COOH) were used as biofunctionalized layers for the synthesized AuNPs. The BSA and HS–PEG–COOH bound to the AuNPs were characterized qualitatively and quantitatively by transmission electron microscope and UV-VS spectrophotometer. The fabricated BSA and HS–PEG–COOH-capped AuNPs were introduced in mouse to study its toxicity and its availability in the liver.

  10. The segregation of silver nanoparticles in low-cost ceramic water filters

    Microsoft Academic Search

    Curtis Larimer; Nicole Ostrowski; Jacquelyn Speakman; Ian Nettleship

    2010-01-01

    As an impregnated constituent in low-cost ceramic water filters, silver nanoparticles have a demonstrated antibacterial effect. The bactericidal mechanism is believed to be based on direct contact between silver and the cell wall of a contaminant organism. In this study microstructural analysis was used to examine the effect of the processing method on the distribution of silver nanoparticles in the

  11. Silver-Based Crystalline Nanoparticles, Microbially Fabricated

    Microsoft Academic Search

    Tanja Klaus; Ralph Joerger; Eva Olsson; Claes-Goran Granqvist

    1999-01-01

    One mechanism of silver resistance in microorganisms is accumulation of the metal ions in the cell. Here, we report on the phenomenon of biosynthesis of silver-based single crystals with well-defined compositions and shapes, such as equilateral triangles and hexagons, in Pseudomonas stutzeri AG259. The crystals were up to 200 nm in size and were often located at the cell poles.

  12. Silver nanoparticles synthesis mediated by new isolates of Bacillus spp., nanoparticle characterization and their activity against Bean Yellow Mosaic Virus and human pathogens.

    PubMed

    Elbeshehy, Essam K F; Elazzazy, Ahmed M; Aggelis, George

    2015-01-01

    Extracellular agents produced by newly isolated bacterial strains were able to catalyze the synthesis of silver nanoparticles (AgNPs). The most effective isolates were identified as Bacillus pumilus, B. persicus, and Bacillus licheniformis using molecular identification. DLS analysis revealed that the AgNPs synthesized by the above strains were in the size range of 77-92 nm. TEM observations showed that the nanoparticles were coated with a capping agent, which was probably involved in nanoparticle stabilization allowing their perfect dispersion in aqueous solutions. FTIR analyses indicated the presence of proteins in the capping agent of the nanoparticles and suggested that the oxidation of hydroxyl groups of peptide hydrolysates (originated from the growth medium) is coupled to the reduction of silver ions. Energy Dispersive X-ray Spectroscopy confirmed the above results. The nanoparticles, especially those synthesized by B. licheniformis, were stable (zeta potential ranged from -16.6 to -21.3 mV) and showed an excellent in vitro antimicrobial activity against important human pathogens and a considerable antiviral activity against the Bean Yellow Mosaic Virus. The significance of the particular antiviral activity is highlighted, given the significant yield reduction in fava bean crops resulting from Bean Yellow Mosaic Virus infections, in many African countries. PMID:26029190

  13. Speciation Matters: Bioavailability of Silver and Silver Sulfide Nanoparticles to Alfalfa (Medicago sativa).

    PubMed

    Stegemeier, John P; Schwab, Fabienne; Colman, Benjamin P; Webb, Samuel M; Newville, Matthew; Lanzirotti, Antonio; Winkler, Christopher; Wiesner, Mark R; Lowry, Gregory V

    2015-07-21

    Terrestrial crops are directly exposed to silver nanoparticles (Ag-NPs) and their environmentally transformed analog silver sulfide nanoparticles (Ag2S-NPs) when wastewater treatment biosolids are applied as fertilizer to agricultural soils. This leads to a need to understand their bioavailability to plants. In the present study, the mechanisms of uptake and distribution of silver in alfalfa (Medicago sativa) were quantified and visualized upon hydroponic exposure to Ag-NPs, Ag2S-NPs, and AgNO3 at 3 mg total Ag/L. Total silver uptake was measured in dried roots and shoots, and the spatial distribution of elements was investigated using transmission electron microscopy (TEM) and synchrotron-based X-ray imaging techniques. Despite large differences in release of Ag(+) ions from the particles, Ag-NPs, Ag2S-NPs, and Ag(+) became associated with plant roots to a similar degree, and exhibited similarly limited (<1%) amounts of translocation of silver into the shoot system. X-ray fluorescence (XRF) mapping revealed differences in the distribution of Ag into roots for each treatment. Silver nanoparticles mainly accumulated in the (columella) border cells and elongation zone, whereas Ag(+) accumulated more uniformly throughout the root. In contrast, Ag2S-NPs remained largely adhered to the root exterior, and the presence of cytoplasmic nano-SixOy aggregates was observed. Exclusively in roots exposed to particulate silver, NPs smaller than the originally dosed NPs were identified by TEM in the cell walls. The apparent accumulation of Ag in the root apoplast determined by XRF, and the presence of small NPs in root cell walls suggests uptake of partially dissolved NPs and translocation along the apoplast. PMID:26106801

  14. Synthesis, effect of capping agents, structural, optical and photoluminescence properties of ZnO nanoparticles

    Microsoft Academic Search

    A. K. Singh; V. Viswanath; V. C. Janu

    2009-01-01

    Zinc oxide nanoparticles were synthesized using chemical method in alcohol base. During synthesis three capping agents, i.e. triethanolamine (TEA), oleic acid and thioglycerol, were used and the effect of concentrations was analyzed for their effectiveness in limiting the particle growth. Thermal stability of ZnO nanoparticles prepared using TEA, oleic acid and thioglycerol capping agents, was studied using thermogravimetric analyzer (TGA).

  15. Green synthesis and characterization of silver nanoparticles using Lantana camara leaf extract.

    PubMed

    Ajitha, B; Ashok Kumar Reddy, Y; Sreedhara Reddy, P

    2015-04-01

    In this work, we have investigated on Lantana camara mediated silver nanoparticles (AgNPs) with different leaf extract (LE) quantity for the evaluation of efficient bactericidal activity. The AgNPs were prepared by simple, capable, eco-friendly and biosynthesis method using L. camara LE. This method allowed the synthesis of crystalline nanoparticles, which was confirmed by X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of metallic silver and elucidates the surface state composition of AgNPs. UV-vis spectra of AgNPs and visual perception of brownish yellow color from colorless reaction mixture confirmed the AgNP formation. Involvement of functional groups of L. camara leaf extract in the reduction and capping process of nanoparticles was well displayed in Fourier transform infrared spectroscopy (FTIR). Decrement of particle size with an increment of leaf extract volume was evident in AFM, TEM images and also through a blue shift in the UV-vis spectra. The rate of formation and size of AgNPs were dependent on LE quantity. Meanwhile, these AgNPs exhibited effective antibacterial activity with the decrement of particle size against all tested bacterial cultures. PMID:25686962

  16. Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents

    PubMed Central

    Ærøe Hyllested, Jes; Espina Palanco, Marta; Hagen, Nicolai; Mogensen, Klaus Bo

    2015-01-01

    Summary Chemicals typically available in plants have the capability to reduce silver and gold salts and to create silver and gold nanoparticles. We report the preparation of silver nanoparticles with sizes between 10 and 300 nm from silver nitrate using fruit extract collected from pineapples and oranges as reducing agents. The evolvement of a characteristic surface plasmon extinction spectrum in the range of 420 nm to 480 nm indicates the formation of silver nanoparticles after mixing silver nitrate solution and fruit extract. Shifts in plasmon peaks over time indicate the growth of nanoparticles. Electron microscopy shows that the shapes of the nanoparticles are different depending on the fruit used for preparation. The green preparation process can result in individual nanoparticles with a very poor tendency to form aggregates with narrow gaps even when aggregation is forced by the addition of NaCl. This explains only modest enhancement factors for near-infrared-excited surface enhanced Raman scattering. In addition to the surface plasmon band, UV–visible absorption spectra show features in the UV range which indicates also the presence of small silver clusters, such as Ag4 2+. The increase of the plasmon absorption correlates with the decrease of absorption band in the UV. This confirms the evolution of silver nanoparticles from silver clusters. The presence of various silver clusters on the surface of the “green” plasmonic silver nanoparticles is also supported by a strong multicolor luminesce signal emitted by the plasmonic particles during 473 nm excitation. PMID:25821667

  17. Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents.

    PubMed

    Ærøe Hyllested, Jes; Espina Palanco, Marta; Hagen, Nicolai; Mogensen, Klaus Bo; Kneipp, Katrin

    2015-01-01

    Chemicals typically available in plants have the capability to reduce silver and gold salts and to create silver and gold nanoparticles. We report the preparation of silver nanoparticles with sizes between 10 and 300 nm from silver nitrate using fruit extract collected from pineapples and oranges as reducing agents. The evolvement of a characteristic surface plasmon extinction spectrum in the range of 420 nm to 480 nm indicates the formation of silver nanoparticles after mixing silver nitrate solution and fruit extract. Shifts in plasmon peaks over time indicate the growth of nanoparticles. Electron microscopy shows that the shapes of the nanoparticles are different depending on the fruit used for preparation. The green preparation process can result in individual nanoparticles with a very poor tendency to form aggregates with narrow gaps even when aggregation is forced by the addition of NaCl. This explains only modest enhancement factors for near-infrared-excited surface enhanced Raman scattering. In addition to the surface plasmon band, UV-visible absorption spectra show features in the UV range which indicates also the presence of small silver clusters, such as Ag4 (2+). The increase of the plasmon absorption correlates with the decrease of absorption band in the UV. This confirms the evolution of silver nanoparticles from silver clusters. The presence of various silver clusters on the surface of the "green" plasmonic silver nanoparticles is also supported by a strong multicolor luminesce signal emitted by the plasmonic particles during 473 nm excitation. PMID:25821667

  18. Disinfection action of electrostatic versus steric-stabilized silver nanoparticles on E. coli under different water chemistries.

    PubMed

    Fauss, Emma K; MacCuspie, Robert I; Oyanedel-Craver, Vinka; Smith, James A; Swami, Nathan S

    2014-01-01

    The capping layer stabilizing silver nanoparticles (AgNPs) affects its aggregation, dissolution, and net disinfection action, especially under conditions of varying water composition, such as, pH, ionic strength and organic matter content. Herein, we correlate the silver ion (Ag(+)) release and reactive oxygen species (ROS) generation rates for AgNPs of varying functionalization to their net disinfection coefficient on Escherichia coli, under conditions of differing water chemistries. For electrostatically stabilized citrate-capped AgNPs, the rate of ROS generation, as measured using a fluorescent dye, is found to dominate over that of Ag(+) release, especially for smaller sized AgNP suspensions (~10nm) at low pH (~6.2). For these AgNPs, the ROS disinfection mechanism is confirmed to dominate net disinfection action, as measured by the live/dead assay, especially at low levels of organic matter. Steric stabilization of AgNPs by protein or starch-capped layers enables disinfection through reducing AgNP aggregation and promoting silver dissolution over ROS generation. We suggest the involvement of protons and dissolved oxygen in causing the independent formation of Ag(+) and ROS, regardless of the AgNP capping layer. While protein-capping layers effectively stabilize AgNPs, the generated ROS is likely dissipated by interference with the bulky capping layer, whereas the interference is lower with citrate-capping layers. Steric stabilization of AgNPs enables disinfection within a wide range of water chemistries, whereas effective disinfection can occur under electrostatic stabilization, only at low NaCl (<1 mmol/L) and organic matter (<5 mg/L) levels. PMID:24060931

  19. Green synthesis of silver nanoparticles for the control of mosquito disease vectors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A biological method was used to synthesize stable silver nanoparticles. The nanoparticles were tested as larvicides against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. Annona squamosa leaf broth (5%) reduced aqueous AgNO3 to stable silver nanoparticles with average particle siz...

  20. Biogenic synthesis of multi-applicative silver nanoparticles by using Ziziphus Jujuba leaf extract.

    PubMed

    Gavade, N L; Kadam, A N; Suwarnkar, M B; Ghodake, V P; Garadkar, K M

    2015-02-01

    Herein, we are reporting for the first time one step biogenic synthesis of silver nanoparticles (AgNPs) at room temperature by using Ziziphus Jujuba leaf extract as a reducing and stabilizing agent. The process of nanoparticles preparation is green, rapid, environmentally benign and cost effective. The synthesized AgNPs were characterized by means of UV-Vis., XRD, FT-IR, TEM, DLS and Zeta potential. The absorption band centered at ?max 434 nm in UV-Vis. reflects surface plasmon resonance (SPR) of AgNPs. XRD analysis revealed, that biosynthesized AgNPs are crystalline in nature with the face centered cubic structure. FT-IR analysis indicates that nanoparticles were capped with the leaf extract. TEM images shows the synthesized nanoparticles are having different shapes with 20-30 nm size. The data obtained from DLS that support the hydrodynamic size of 28 nm. Zeta potential of -26.4 mV indicates that the nanoparticles were highly stable in colloidal state. The effect of pH, quantity of leaf extract and concentrations of AgNO3 were also studied to attend control over the particle size and stability. The synthesized AgNPs shows highly efficient catalytic activity towards the reduction of anthropogenic pollutant 4-nitrophenol (4-NP) and Methylene Blue (MB) for environmental protection. Synthesized AgNPs also exhibited good antimicrobial activity against Escherichia coli. PMID:25459621

  1. Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis

    NASA Astrophysics Data System (ADS)

    Petkova, Galina A.; Záruba, ?amil; Žvátora, Pavel; Král, Vladimír

    2012-06-01

    In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45 nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222 nm with about 4 to 7 nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5 nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15 days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective ( ee > 99%) synthesis of ( S)-7-hydroxy-2-tetralol.

  2. Gold and silver nanoparticles for biomolecule immobilization and enzymatic catalysis.

    PubMed

    Petkova, Galina A; Záruba, Capital Ka Cyrillicamil; Zvátora, Pavel; Král, Vladimír

    2012-01-01

    In this work, a simple method for alcohol synthesis with high enantiomeric purity was proposed. For this, colloidal gold and silver surface modifications with 3-mercaptopropanoic acid and cysteamine were used to generate carboxyl and amine functionalized gold and silver nanoparticles of 15 and 45?nm, respectively. Alcohol dehydrogenase from Thermoanaerobium brockii (TbADH) and its cofactor (NADPH) were physical and covalent (through direct adsorption and using cross-linker) immobilized on nanoparticles' surface. In contrast to the physical and covalent immobilizations that led to a loss of 90% of the initial enzyme activity and 98% immobilization, the use of a cross-linker in immobilization process promoted a loss to 30% of the initial enzyme activity and >92% immobilization. The yield of NADPH immobilization was about 80%. The best results in terms of activity were obtained with Ag-citr nanoparticle functionalized with carboxyl groups (Ag-COOH), Au-COOH(CTAB), and Au-citr functionalized with amine groups and stabilized with CTAB (Au-NH2(CTAB)) nanoparticles treated with 0.7% and 1.0% glutaraldehyde. Enzyme conformation upon immobilization was studied using fluorescence and circular dichroism spectroscopies. Shift in ellipticity at 222?nm with about 4 to 7?nm and significant decreasing in fluorescence emission for all bioconjugates were observed by binding of TbADH to silver/gold nanoparticles. Emission redshifting of 5?nm only for Ag-COOH-TbADH bioconjugate demonstrated change in the microenvironment of TbADH. Enzyme immobilization on glutaraldehyde-treated Au-NH2(CTAB) nanoparticles promotes an additional stabilization preserving about 50% of enzyme activity after 15?days storage. Nanoparticles attached-TbADH-NADPH systems were used for enantioselective (ee?>?99%) synthesis of (S)-7-hydroxy-2-tetralol. PMID:22655978

  3. Green synthesis of silver nanoparticles using cellulose extracted from an aquatic weed; water hyacinth.

    PubMed

    Mochochoko, Tanki; Oluwafemi, Oluwatobi S; Jumbam, Denis N; Songca, Sandile P

    2013-10-15

    As part of the desire to save the environment through "green" chemistry practices, we herein report an environmentally benign synthesis of silver nanoparticles (Ag-NPs) using cellulose extracted from an environmentally problematic aquatic weed, water hyacinth (WH), as both reducing and capping agent in an aqueous medium. By varying the pH of the solution and reaction time, the temporal evolutions of the optical and morphological properties of the as-synthesised Ag-NPs were investigated. The as-synthesised cellulose capped silver nanoparticles (C-Ag-NPs) were characterised using Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The maximum surface plasmon resonance (SPR) peak decreased as the pH increased indicating that an increase in the pH of the solution favoured the formation of smaller particles. In addition, instantaneous change in the colour of the solution from colourless to brown within 5 min at pH 11 showed that the rate of reduction is faster at this pH compared to those at lower pH. The TEM micrographs showed that the materials are small, highly monodispersed and spherical in shape. The average particle mean diameters were calculated to be 5.69±5.89 nm, 4.53±1.36 nm and 2.68±0.69 nm nm at pH 4, 8 and 11 respectively. The HRTEM confirmed the crystallinity of the material while the FTIR spectra confirmed the capping of the as-synthesised Ag-NPs by the cellulose. It has been shown therefore that based on this synthetic method, this aquatic plant can be used to the advantage of mankind. PMID:23987347

  4. Effect of temperature in synthesis of silver nanoparticles in triblock copolymer micellar solution

    Microsoft Academic Search

    A. K. M. Maidul Islam; M. Mukherjee

    2011-01-01

    Knowing that poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) in aqueous solution is thermoresponsive, the effect of temperature on formation and stabilisation of silver nanoparticles has been investigated systematically. Synthesis of silver nanoparticles was achieved from silver ammonia complex [Ag(NH3)2] in aqueous solution of hydroxyl terminated PEO–PPO–PEO at four different temperatures. A non-Arrhenius behaviour for the rate of silver reduction with temperature

  5. Synthesis and Study of Silver Nanoparticles

    ERIC Educational Resources Information Center

    Soloman, Sally D.; Bahadory, Mozghan; Jeyarajasingam, Aravindan V.; Rutkowsky, Susan A.; Boritz, Charles; Mulfinger, Lorraine

    2007-01-01

    A laboratory experiment was conducted in which the students synthesized yellow colloidal silver, estimate particle size using visible spectroscopy and studied aggregation effects. The students were thus introduced to nanotechnology along with other topics such as redox chemistry, limiting and excess reactants, spectroscopy and atomic size.

  6. Effect of silver nanoparticles on human mesenchymal stem cell differentiation

    PubMed Central

    Diendorf, Jörg; Epple, Matthias; Schildhauer, Thomas A; Köller, Manfred

    2014-01-01

    Summary Background: Silver nanoparticles (Ag-NP) are one of the fastest growing products in nano-medicine due to their enhanced antibacterial activity at the nanoscale level. In biomedicine, hundreds of products have been coated with Ag-NP. For example, various medical devices include silver, such as surgical instruments, bone implants and wound dressings. After the degradation of these materials, or depending on the coating technique, silver in nanoparticle or ion form can be released and may come into close contact with tissues and cells. Despite incorporation of Ag-NP as an antibacterial agent in different products, the toxicological and biological effects of silver in the human body after long-term and low-concentration exposure are not well understood. In the current study, we investigated the effects of both ionic and nanoparticulate silver on the differentiation of human mesenchymal stem cells (hMSCs) into adipogenic, osteogenic and chondrogenic lineages and on the secretion of the respective differentiation markers adiponectin, osteocalcin and aggrecan. Results: As shown through laser scanning microscopy, Ag-NP with a size of 80 nm (hydrodynamic diameter) were taken up into hMSCs as nanoparticulate material. After 24 h of incubation, these Ag-NP were mainly found in the endo-lysosomal cell compartment as agglomerated material. Cytotoxicity was observed for differentiated or undifferentiated hMSCs treated with high silver concentrations (?20 µg·mL?1 Ag-NP; ?1.5 µg·mL?1 Ag+ ions) but not with low-concentration treatments (?10 µg·mL?1 Ag-NP; ?1.0 µg·mL?1 Ag+ ions). Subtoxic concentrations of Ag-NP and Ag+ ions impaired the adipogenic and osteogenic differentiation of hMSCs in a concentration-dependent manner, whereas chondrogenic differentiation was unaffected after 21 d of incubation. In contrast to aggrecan, the inhibitory effect of adipogenic and osteogenic differentiation was confirmed by a decrease in the secretion of specific biomarkers, including adiponectin (adipocytes) and osteocalcin (osteoblasts). Conclusion: Aside from the well-studied antibacterial effect of silver, little is known about the influence of nano-silver on cell differentiation processes. Our results demonstrate that ionic or nanoparticulate silver attenuates the adipogenic and osteogenic differentiation of hMSCs even at non-toxic concentrations. Therefore, more studies are needed to investigate the effects of silver species on cells at low concentrations during long-term treatment. PMID:25551033

  7. Oxidative stress mediated cytotoxicity of biologically synthesized silver nanoparticles in human lung epithelial adenocarcinoma cell line

    NASA Astrophysics Data System (ADS)

    Han, Jae Woong; Gurunathan, Sangiliyandi; Jeong, Jae-Kyo; Choi, Yun-Jung; Kwon, Deug-Nam; Park, Jin-Ki; Kim, Jin-Hoi

    2014-09-01

    The goal of the present study was to investigate the toxicity of biologically prepared small size of silver nanoparticles in human lung epithelial adenocarcinoma cells A549. Herein, we describe a facile method for the synthesis of silver nanoparticles by treating the supernatant from a culture of Escherichia coli with silver nitrate . The formation of silver nanoparticles was characterized using various analytical techniques. The results from UV-visible (UV-vis) spectroscopy and X-ray diffraction analysis show a characteristic strong resonance centered at 420 nm and a single crystalline nature, respectively. Fourier transform infrared spectroscopy confirmed the possible bio-molecules responsible for the reduction of silver from silver nitrate into nanoparticles. The particle size analyzer and transmission electron microscopy results suggest that silver nanoparticles are spherical in shape with an average diameter of 15 nm. The results derived from in vitro studies showed a concentration-dependent decrease in cell viability when A549 cells were exposed to silver nanoparticles. This decrease in cell viability corresponded to increased leakage of lactate dehydrogenase (LDH), increased intracellular reactive oxygen species generation (ROS), and decreased mitochondrial transmembrane potential (MTP). Furthermore, uptake and intracellular localization of silver nanoparticles were observed and were accompanied by accumulation of autophagosomes and autolysosomes in A549 cells. The results indicate that silver nanoparticles play a significant role in apoptosis. Interestingly, biologically synthesized silver nanoparticles showed more potent cytotoxicity at the concentrations tested compared to that shown by chemically synthesized silver nanoparticles. Therefore, our results demonstrated that human lung epithelial A549 cells could provide a valuable model to assess the cytotoxicity of silver nanoparticles.

  8. Extracellular conversion of silver ions into silver nanoparticles by protozoan Tetrahymena thermophila.

    PubMed

    Juganson, Katre; Mortimer, Monika; Ivask, Angela; Kasemets, Kaja; Kahru, Anne

    2013-01-01

    In the current study, cell-free exudates of the ciliated protozoan Tetrahymena thermophila were shown to progressively convert silver nitrate to silver nanoparticles (Ag NPs) under illumination at ambient temperature. The formation of Ag NPs in the reaction mixture was evidenced by gradual colour changes, appearance of a specific absorbance peak (420–450 nm) and visualization using scanning electron microscopy coupled to an energy-dispersive X-ray spectrometer. After 2 h of incubation the mean hydrodynamic size of the Ag NPs was 70 nm. Seven days of incubation resulted in larger agglomerates and a significant decrease in silver toxicity to T. thermophila, accompanied by about 100-fold reduction in the silver ion concentration. Protein analysis indicated an extensive extracellular protein binding by the Ag NPs formed in the protozoan exudates. As protozoa are important components in wastewater treatment, their ability to sequester silver ions into a less bioavailable and less toxic form of silver (e.g. NPs) may be one of the adaption mechanisms of ciliate survival in contaminated environments. PMID:24592441

  9. PEG conjugated citrate-capped magnetite nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Cheraghipour, Elham; Tamaddon, A. M.; Javadpour, S.; Bruce, I. J.

    2013-02-01

    We aim to develop polyethylene glycol decorated, citric acid capped magnetite nanoparticles (MNPs) with proper physicochemical characteristics including particle size distribution, morphology, magnetic property and stability in a biologic medium. MNP of about 10 nm were synthesized by a biocompatible chemical co-precipitation of Fe2+ and Fe3+ in an ammonia solution. A synthetic methodology has been developed to get a well dispersed and homogeneous aqueous suspension of MNPs. The naked MNPs are often insufficient for their stability, hydrophilicity and further functionalization. In order to overcome these limitations, citric acid was used to stabilize the magnetite particle suspension, which was anchored on the surface of freshly prepared MNPs by a direct addition method. Polyethylene glycol was covalently attached to the carboxylic moieties of citric acid anchored MNPs by carbodiimide chemistry. The microstructure and morphology of the nanoparticles were characterized by X-ray diffraction and transmission electron microscopy, and Fourier transform infrared spectroscopy. Also, the magnetic properties were investigated by vibrating sample magnetometry. It was found that the nanoparticles demonstrated superparamagnetic behavior.

  10. Biocompatible capped iron oxide nanoparticles for Vibrio cholerae detection.

    PubMed

    Sharma, Anshu; Baral, Dinesh; Rawat, Kamla; Solanki, Pratima R; Bohidar, H B

    2015-05-01

    We report the studies relating to fabrication of an efficient immunosensor for Vibrio cholerae detection. Magnetite (iron oxide (Fe(3)O(4))) nanoparticles (NPs) have been synthesized by the co-precipitation method and capped by citric acid (CA). These NPs were electrophoretically deposited onto indium-tin-oxide (ITO)-coated glass substrate and used for immobilization of monoclonal antibodies against Vibrio cholerae (Ab) and bovine serum albumin (BSA) for Vibrio cholerae detection using an electrochemical technique. The structural and morphological studies of Fe(3)O(4) and CA-Fe(3)O(4)/ITO were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and dynamic light scattering (DLS) techniques. The average crystalline size of Fe(3)O(4), CA-Fe(3)O(4) nanoparticles obtained were about 29 ± 1 nm and 37 ± 1 nm, respectively. The hydrodynamic radius of the nanoparticles was found to be 77.35 nm (Fe(3)O(4)) and 189.51 nm (CA-Fe(3)O(4)) by DLS measurement. The results of electrochemical response studies of the fabricated BSA/Ab/CA-Fe(2)O(3)/ITO immunosensor exhibits a good detection range of 12.5-500 ng mL(-1) with a low detection limit of 0.32 ng mL(-1), sensitivity 0.03 ?/ng ml(-1) cm(-2), and reproducibility more than 11 times. PMID:25850702

  11. Synthesis and NMR characterization of ligand-capped metal and metal-oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Sharma, Ramesh

    Ligand-capped metal and metal-oxide nanoparticles (NPs) have some interesting and useful physical properties that are not present in their respective bulk materials. These properties are of research interest in many applications such as catalysis, drug delivery, biological imaging, and plasmonics. In such applications, it is critical to understand the surface structure of NPs and the roles played by the surface bound ligands. To characterize surface environment, ligand dynamics, and exchange kinetics, ligand-capped metal and metal-oxide NPs are synthesized and studied by multinuclear NMR. Phosphines and phosphonic acids are used to passivate metal (gold and silver) and metal-oxide (tin dioxide) NPs in different sizes (1-5 nm) by following published procedures or original synthesis methods. In both solution and solid state NMR, the 31P chemical shift of surface-bound ligands are distinctly different from those observed for free ligands. Additionally, NMR line widths in surface-bound ligands are highly broadened compared to those of free ligands. The lines are broadened due to both homogeneous and inhomogeneous broadening mechanisms, determined through hole burning NMR and spin-spin relaxation measurements. In small particles (< 2 nm), the main source of line broadening is inhomogeneous and originates due to structural heterogeneity and underlying chemical shift distributions. In large particles (> 2 nm), both inhomogeneous and homogeneous line broadening mechanisms are present. When the particles' sizes increase from small to large, the homogeneous broadening mechanism becomes dominant due to strong nuclear-electron interaction and reintroduction of residual dipolar coupling as shown by a combination of 1H, 13C and 31P NMR. Results from a series of ligand exchange experiments in silver and gold NPs further indicate the presence of Au(I) and Ag(I) on the particle surfaces.

  12. Can silver nanoparticles be useful as potential biological labels?

    NASA Astrophysics Data System (ADS)

    Schrand, Amanda M.; Braydich-Stolle, Laura K.; Schlager, John J.; Dai, Liming; Hussain, Saber M.

    2008-06-01

    Silver (Ag) nanoparticles have unique plasmon-resonant optical scattering properties that are finding use in nanomedical applications such as signal enhancers, optical sensors, and biomarkers. In this study, we examined the chemical and biological properties of Ag nanoparticles of similar sizes, but that differed primarily in their surface chemistry (hydrocarbon versus polysaccharide), in neuroblastoma cells for their potential use as biological labels. We observed strong optical labeling of the cells in a high illumination light microscopy system after 24 h of incubation due to the excitation of plasmon resonance by both types of Ag nanoparticle. Surface binding of both types of Ag nanoparticle to the plasma membrane of the cells was verified with scanning electron microscopy as well as the internalization and localization of the Ag nanoparticles into intracellular vacuoles in thin cell sections with transmission electron microscopy. However, the induction of reactive oxygen species (ROS), degradation of mitochondrial membrane integrity, disruption of the actin cytoskeleton, and reduction in proliferation after stimulation with nerve growth factor were found after incubation with Ag nanoparticles at concentrations of 25 µg ml-1 or greater, with a more pronounced effect produced by the hydrocarbon-based Ag nanoparticles in most cases. Therefore, the use of Ag nanoparticles as potential biological labels, even if the surface is chemically modified with a biocompatible material, should be approached with caution.

  13. Silver nanoparticles impact phototrophic biofilm communities to a considerably higher degree than ionic silver.

    PubMed

    González, Aridane G; Mombo, Stéphane; Leflaive, Joséphine; Lamy, Alexandre; Pokrovsky, Oleg S; Rols, Jean-Luc

    2015-06-01

    Due to the significant increase in nanoparticle production and especially that of silver nanoparticles over the past decade, the toxicity of silver in both ionic (Ag(+)) and nanoparticulate (AgNPs) form must be studied in detail in order to understand their impact on natural ecosystems. A comparative study of the effect of AgNPs and ionic silver on two independent phototrophic biofilms was conducted in a rotating annular bioreactor (RAB) operating under constant conditions. The concentration of dissolved silver in the inlet solution was progressively increased every 4 days of exposure, from 0.1 to 100 ?g L(-1). In the course of the 40-day experiment, biofilm samples were collected to determine the evolution of biomass, chlorophyll-a, as well as photosynthetic and heterotrophic enzymatic activities in response to silver addition. Analysis of both dissolved and particulate silver allowed quantification of the distribution coefficient and uptake rate constants. The presence of both AgNPs and Ag(+) produced significant changes in the biofilm structure, decreasing the relative percentage of Diatomophyceae and Cyanophyceae and increasing the relative percentage of Chlorophyceae. The accumulation capacity of the phototrophic biofilm with respect to ionic silver and the corresponding distribution coefficients were an order of magnitude higher than those of the phototrophic biofilm with respect to AgNPs. Higher levels of AgNPs decreased the biomass from 8.6?±?0.2 mg cm(-2) for 0-10 ?g L(-1) AgNPs to 6.0?±?0.1 mg cm(-2) for 100 ?g L(-1) added AgNPs, whereas ionic silver did not have any toxic effect on the biofilm growth up to 100 ?g L(-1) of added Ag(+). At the same time, AgNPs did not significantly affect the photosynthetic activity of the biofilm surface communities compared to Ag(+). It can thus be hypothesized that negatively charged AgNPs may travel through the biofilm water channels, thereby affecting the whole biofilm structure. In contrast, positively charged Ag(+) is bound at the cell surfaces and EPS, thus blocking its further flux within the biofilm layers. On the whole, the phototrophic biofilm demonstrated significant capacities to accumulate silver within the surface layers. The main mechanism to avoid the toxic effects is metal complexation with exopolysaccharides and accumulation within cell walls, especially pronounced under Ag(+) stress. The significant AgNPs and Ag(+) uptake capacities of phototrophic biofilm make it a highly resistant ecosystem in silver-polluted river waters. PMID:25539705

  14. Stress-induced phase transformation and optical coupling of silver nanoparticle superlattices into mechanically stable nanowires

    NASA Astrophysics Data System (ADS)

    Li, Binsong; Wen, Xiaodong; Li, Ruipeng; Wang, Zhongwu; Clem, Paul G.; Fan, Hongyou

    2014-06-01

    One-dimensional silver materials display unique optical and electrical properties with promise as functional blocks for a new generation of nanoelectronics. To date, synthetic approaches and property engineering of silver nanowires have primarily focused on chemical methods. Here we report a simple physical method of metal nanowire synthesis, based on stress-induced phase transformation and sintering of spherical Ag nanoparticle superlattices. Two phase transformations of nanoparticles under stress have been observed at distinct length scales. First, the lattice dimensions of silver nanoparticle superlattices may be reversibly manipulated between 0-8?GPa compressive stresses to enable systematic and reversible changes in mesoscale optical coupling between silver nanoparticles. Second, stresses greater than 8?GPa induced an atomic lattice phase transformation, which induced sintering of silver nanoparticles into micron-length scale nanowires. The nanowire synthesis mechanism displays a dependence on both nanoparticle crystal surface orientation and presence of particular grain boundaries to enable nanoparticle consolidation into nanowires.

  15. In vitro permeability of silver nanoparticles through porcine oromucosal membrane.

    PubMed

    Mauro, Marcella; Crosera, Matteo; Bianco, Carlotta; Bellomo, Francesca; Bovenzi, Massimo; Adami, Gianpiero; Larese Filon, Francesca

    2015-08-01

    Silver nanoparticles (AgNPs) can come in contact with human oral mucosa due to their wide use in food industry and hygiene devices. We evaluate transmucosal absorption of 19nm AgNPs using excised porcine buccal mucosa applied on Franz diffusion cells. Two donor solutions were used: one containing AgNPs (0.5g/L) and one derived from the ultrafiltration of the former and containing only Ag in its soluble form. Experiments were carried out separately for 4h. Silver flux permeation was demonstrated through oral mucosa, showing similar values for AgNPs (6.8±4.5ngcm(-2)h(-1)) and Ag ions (5.2±4.3ngcm(-2)h(-1)). Our study demonstrates that silver can permeate the oromucosal barrier and that absorption is substantially due to Ag ions, since no permeation difference was found using the two solutions. Mucosal absorption has to be considered in further risk assessment studies. PMID:26001797

  16. Spectroscopic analysis of biologically synthesized silver nanoparticles under clinorotation

    NASA Astrophysics Data System (ADS)

    Jagtap, Sagar; Vidyasagar, Pandit; Ghemud, Vipul; Dixit, Jyotsana

    Nanoparticles are one of the hot topics of research due to their size dependent optical, electrical and magnetic properties & their anti-bacterial and anti-fungal nature. Synthesis of nano particles can be done by various physical and chemical methods. However, Biosynthesis of nanoparticles is environment friendly, can take place around room temperature, and require little intervention or input of energy. In the present study, the synthesis of silver nanoparticles (AgNPs) using bacteria and the effect of clinorotation on rate of synthesis is discussed. The freshly grown bacterial isolate was inoculated in to 250-ml Erlenmeyer flask containing 50 ml sterile nutrient broth (LB). The cultured flasks were incubated in a shaker at 120 rpm for 24 h at 370C. Culture was centrifuged at 10,000 rpm for 10 min. The supernatant was used for carrying extracellular production of silver nanoparticles by mixing it with 5mM AgNO3 solution. The above solution was clinorotated at 2 rpm for 24 h. The synthesis was carried out at 60oC. Visual observation was conducted periodically to check for the nanoparticles formation in normal gravity as well as under clinorotation. UV-visible spectroscopic analysis showed that rate of synthesis was faster in case of clinorotated sample than control. Further, the results of FTIR and XRD characterization will be discussed.

  17. Leaf extract assisted green synthesis and characterization of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Ajitha, B.; Reddy, Y. Ashok Kumar; Reddy, P. Sreedhara

    2015-06-01

    In the present study AgNPs were synthesized through simple green route using leaf extract of Crossandra nilotica which act as combined reductant and surfactant at once. The bio-reduced AgNPs were appropriately characterized for studying their structural and optical properties. TEM micrograph confirms the formation of spherical nanoparticles without any agglomeration and particle size range was found to be 12 nm. UV-Vis study elucidates the presence of single plasmon peak, attesting the spherical nanoparticles formation. FTIR results revealed that different functional groups of leaf extract are responsible for the reduction of silver ions and their stabilization.

  18. Biosynthesis of silver nanoparticles from Tribulus terrestris and its antimicrobial activity: a novel biological approach.

    PubMed

    Gopinath, V; MubarakAli, D; Priyadarshini, S; Priyadharsshini, N Meera; Thajuddin, N; Velusamy, P

    2012-08-01

    In the recent decades, increased development of green synthesis of nanoparticles is inevitable because of its incredible applications in all fields of science. There were numerous work have been produced based on the plant and its extract mediated synthesis of nanoparticles, in this present study to explore that the novel approaches for the biosynthesis of silver nanoparticles using plant fruit bodies. The plant, Tribulus terrestris L. fruit bodies are used in this study, where the dried fruit body extract was mixed with silver nitrate in order to synthesis of silver nanoparticles. The active phytochemicals present in the plant were responsible for the quick reduction of silver ion (Ag(+)) to metallic silver nanoparticles (Ag(0)). The reduced silver nanoparticles were characterized by Transmission Electron Microscope (TEM), Atomic Force Microscope (AFM), XRD, FTIR, UV-vis spectroscopy. The spherical shaped silver nanoparticles were observed and it was found to be 16-28 nm range of sizes. The diffraction pattern also confirmed that the higher percentage of silver with fine particles size. The antibacterial property of synthesized nanoparticles was observed by Kirby-Bauer method with clinically isolated multi-drug resistant bacteria such as Streptococcus pyogens, Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The plant materials mediated synthesis of silver nanoparticles have comparatively rapid and less expensive and wide application to antibacterial therapy in modern medicine. PMID:22521683

  19. Synergy of Silver Nanoparticles and Aztreonam against Pseudomonas aeruginosa PAO1 Biofilms

    PubMed Central

    Park, Amber J.; Vis, Emily C.; Harris, Robert J.

    2014-01-01

    Pathogenic bacterial biofilms, such as those found in the lungs of patients with cystic fibrosis (CF), exhibit increased antimicrobial resistance, due in part to the inherent architecture of the biofilm community. The protection provided by the biofilm limits antimicrobial dispersion and penetration and reduces the efficacy of antibiotics that normally inhibit planktonic cell growth. Thus, alternative antimicrobial strategies are required to combat persistent infections. The antimicrobial properties of silver have been known for decades, but silver and silver-containing compounds have recently seen renewed interest as antimicrobial agents for treating bacterial infections. The goal of this study was to assess the efficacy of citrate-capped silver nanoparticles (AgNPs) of various sizes, alone and in combination with the monobactam antibiotic aztreonam, to inhibit Pseudomonas aeruginosa PAO1 biofilms. Among the different sizes of AgNPs examined, 10-nm nanoparticles were most effective in inhibiting the recovery of P. aeruginosa biofilm cultures and showed synergy of inhibition when combined with sub-MIC levels of aztreonam. Visualization of biofilms treated with combinations of 10-nm AgNPs and aztreonam indicated that the synergistic bactericidal effects are likely caused by better penetration of the small AgNPs into the biofilm matrix, which enhances the deleterious effects of aztreonam against the cell envelope of P. aeruginosa within the biofilms. These data suggest that small AgNPs synergistically enhance the antimicrobial effects of aztreonam against P. aeruginosa in vitro, and they reveal a potential role for combinations of small AgNPs and antibiotics in treating patients with chronic infections. PMID:25049240

  20. Study of silver nanoparticle–hemoglobin interaction and composite formation

    Microsoft Academic Search

    Mrityunjoy Mahato; Prabir Pal; Bidisha Tah; Manash Ghosh; G. B. Talapatra

    2011-01-01

    Nanoscience is now an expanding field of research and finds potential application in biomedical area, but it is limited due to lack of comprehensive knowledge of the interactions operating in nano-bio system. Here, we report the studies on the interaction and formation of nano-bio complex between silver nanoparticle (AgNP) and human blood protein hemoglobin (Hb). We have employed several spectroscopic

  1. Bactericidal effect of silver nanoparticles against multidrug-resistant bacteria

    Microsoft Academic Search

    Humberto H. Lara; Nilda V. Ayala-Núñez; Liliana del Carmen Ixtepan Turrent; Cristina Rodríguez Padilla

    2010-01-01

    Infections caused by drug-resistant microorganisms result in significant increases in mortality, morbidity, and cost related\\u000a to prolonged treatments. The antibacterial activity of silver nanoparticles against some drug-resistant bacteria has been\\u000a established, but further investigation is needed to determine whether these particles could be an option for the treatment\\u000a and prevention of drug-resistant microbial infections. Hence, we challenged different drug-resistant pathogens

  2. Electronic conductivity of alkyne-capped ruthenium nanoparticles

    NASA Astrophysics Data System (ADS)

    Kang, Xiongwu; Chen, Shaowei

    2012-06-01

    Ruthenium nanoparticles (2.12 +/- 0.72 nm in diameter) were stabilized by the self-assembly of alkyne molecules (from 1-hexyne to 1-hexadecyne) onto the Ru surface by virtue of the formation of Ru-vinylidene interfacial linkages. Infrared measurements depicted three vibrational bands at 2050 cm-1, 1980 cm-1 and 1950 cm-1, which were ascribed to the vibrational stretches of the terminal triple bonds that were bound onto the nanoparticle surface. Thermogravimetric analysis showed that there were about 65 to 96 alkyne ligands per nanoparticle (depending on the ligand chainlength), corresponding to a molecular footprint of 20 to 15 Å2. This suggests that the ligands likely adopted a head-on configuration on the nanoparticle surface, consistent with a vinylidene bonding linkage due to interfacial tautomeric rearrangements. With this conjugated interfacial bonding interaction, electronic conductivity measurements of the corresponding nanoparticle solid films showed that the nanoparticles all exhibited linear current-potential curves within the potential range of -0.8 V to +0.8 V at varied temperatures (200 to 300 K). The ohmic characters were partly ascribed to the spilling of core electrons into the organic capping layer that facilitated interparticle charge transfer. Furthermore, based on the temperature dependence of the nanoparticle electronic conductivity, the activation energy for interparticle charge transfer was estimated to be in the range of 70 to 90 meV and significantly, the coupling coefficient (?) was found to be 0.31 Å-1 for nanoparticles stabilized by short-chain alkynes (1-hexyne, 1-octyne, and 1-decyne), and 1.44 Å-1 for those with long alkynes such as 1-dodecyne, 1-tetradecyne, and 1-hexadecyne. This may be accounted for by the relative contributions of the conjugated metal-ligand interfacial bonding interactions versus the saturated aliphatic backbones of the alkyne ligands to the control of interparticle charge transfer.Ruthenium nanoparticles (2.12 +/- 0.72 nm in diameter) were stabilized by the self-assembly of alkyne molecules (from 1-hexyne to 1-hexadecyne) onto the Ru surface by virtue of the formation of Ru-vinylidene interfacial linkages. Infrared measurements depicted three vibrational bands at 2050 cm-1, 1980 cm-1 and 1950 cm-1, which were ascribed to the vibrational stretches of the terminal triple bonds that were bound onto the nanoparticle surface. Thermogravimetric analysis showed that there were about 65 to 96 alkyne ligands per nanoparticle (depending on the ligand chainlength), corresponding to a molecular footprint of 20 to 15 Å2. This suggests that the ligands likely adopted a head-on configuration on the nanoparticle surface, consistent with a vinylidene bonding linkage due to interfacial tautomeric rearrangements. With this conjugated interfacial bonding interaction, electronic conductivity measurements of the corresponding nanoparticle solid films showed that the nanoparticles all exhibited linear current-potential curves within the potential range of -0.8 V to +0.8 V at varied temperatures (200 to 300 K). The ohmic characters were partly ascribed to the spilling of core electrons into the organic capping layer that facilitated interparticle charge transfer. Furthermore, based on the temperature dependence of the nanoparticle electronic conductivity, the activation energy for interparticle charge transfer was estimated to be in the range of 70 to 90 meV and significantly, the coupling coefficient (?) was found to be 0.31 Å-1 for nanoparticles stabilized by short-chain alkynes (1-hexyne, 1-octyne, and 1-decyne), and 1.44 Å-1 for those with long alkynes such as 1-dodecyne, 1-tetradecyne, and 1-hexadecyne. This may be accounted for by the relative contributions of the conjugated metal-ligand interfacial bonding interactions versus the saturated aliphatic backbones of the alkyne ligands to the control of interparticle charge transfer. Electronic supplementary information (ESI) available: TEM micrograph, derivative thermogravimetric curves, and UV-vis and fluorescence spectra of the

  3. An ultrastable conjugate of silver nanoparticles and protein formed through weak interactions.

    PubMed

    Brahmkhatri, Varsha P; Chandra, Kousik; Dubey, Abhinav; Atreya, Hanudatta S

    2015-07-23

    In recent years, silver nanoparticles (AgNPs) have attracted significant attention owing to their unique physicochemical, optical, conductive and antimicrobial properties. One of the properties of AgNPs which is crucial for all applications is their stability. In the present study we unravel a mechanism through which silver nanoparticles are rendered ultrastable in an aqueous solution in complex with the protein ubiquitin (Ubq). This involves a dynamic and reversible association and dissociation of ubiquitin from the surface of AgNP. The exchange occurs at a rate much greater than 25 s(-1) implying a residence time of <40 ms for the protein. The AgNP-Ubq complex remains stable for months due to steric stabilization over a wide pH range compared to unconjugated AgNPs. NMR studies reveal that the protein molecules bind reversibly to AgNP with an approximate dissociation constant of 55 ?M and undergo fast exchange. At pH > 4 the positively charged surface of the protein comes in contact with the citrate capped AgNP surface. Further, NMR relaxation-based experiments suggest that in addition to the dynamic exchange, a conformational rearrangement of the protein takes place upon binding to AgNP. The ultrastability of the AgNP-Ubq complex was found to be useful for its anti-microbial activity, which allowed the recycling of this complex multiple times without the loss of stability. Altogether, the study provides new insights into the mechanism of protein-silver nanoparticle interactions and opens up new avenues for its application in a wide range of systems. PMID:26166696

  4. Phycosynthesis of silver nanoparticles and photocatalytic degradation of methyl orange dye using silver (Ag) nanoparticles synthesized from Hypnea musciformis (Wulfen) J.V. Lamouroux

    NASA Astrophysics Data System (ADS)

    Ganapathy Selvam, G.; Sivakumar, K.

    2014-09-01

    In the present investigation, simple and eco-friendly chemical reaction for the synthesis reported on biological synthesis of nano-sized silver and biosynthesis of silver nanoparticles using Hypnea musciformis at room temperature along with photocatalytic degradation of methyl orange dye. The nanoparticles of silver were formed by the reduction of silver nitrate to aqueous silver metal ions during exposure to the extract of red alga H. musciformis. The optical properties of the obtained silver nanoparticles were characterized by applying UV-visible absorption and room temperature photoluminescence. The X-ray diffraction results revealed that the synthesized silver nanoparticles were in the cubic phase. The existence of functional groups was identified using Fourier transform infrared spectroscopy. The morphology and size of the synthesized particles were studied with atomic force microscope measurements. Photocatalytic degradation of methyl orange was measured spectrophotometrically by using silver as nanocatalyst under visible light illumination. The results revealed that biosynthesized silver nanoparticles using H. musciformis was found to be impressive in degrading methyl orange.

  5. Phycosynthesis of silver nanoparticles and photocatalytic degradation of methyl orange dye using silver (Ag) nanoparticles synthesized from Hypnea musciformis (Wulfen) J.V. Lamouroux

    NASA Astrophysics Data System (ADS)

    Ganapathy Selvam, G.; Sivakumar, K.

    2015-06-01

    In the present investigation, simple and eco-friendly chemical reaction for the synthesis reported on biological synthesis of nano-sized silver and biosynthesis of silver nanoparticles using Hypnea musciformis at room temperature along with photocatalytic degradation of methyl orange dye. The nanoparticles of silver were formed by the reduction of silver nitrate to aqueous silver metal ions during exposure to the extract of red alga H. musciformis. The optical properties of the obtained silver nanoparticles were characterized by applying UV-visible absorption and room temperature photoluminescence. The X-ray diffraction results revealed that the synthesized silver nanoparticles were in the cubic phase. The existence of functional groups was identified using Fourier transform infrared spectroscopy. The morphology and size of the synthesized particles were studied with atomic force microscope measurements. Photocatalytic degradation of methyl orange was measured spectrophotometrically by using silver as nanocatalyst under visible light illumination. The results revealed that biosynthesized silver nanoparticles using H. musciformis was found to be impressive in degrading methyl orange.

  6. Characterization by spectroscopic Ellipsometry, the physical properties of silver nanoparticles.

    NASA Astrophysics Data System (ADS)

    Coanga, Jean-Maurice

    2013-04-01

    Physicists are able to change their minds through their experiments. I think it is time to go kick the curse and go further in research if we want a human future. I work in the Nano-Optics and Plasmonics research. I defined with ellipsomètrie the structure of new type of Nano particles of silver. It's same be act quickly to replace the old dirty leaded electronic-connexion chip and by the other hand to find a new way for the heath care of cancer disease by nanoparticles the next killers of bad cells. Silver nanoparticle layers are obtained by Spark Plasma Sintering are investigated as an alternative to lead alloy based material for solder joint in power mechatronics modules. These layers are characterized by mean of conventional techniques that is the dilatometry technique, the resistivity measurement through the van der Pauw method, and the flash laser technique. Furthermore, the nanoparticles of silver layer are deeply studied by UV-Visible spectroscopic ellipsometry. Spectroscopic angles parameters are determined in function of temperature and dielectric constants are deduced and analyzed through an optical model which takes into account a Drude and a Lorentz component within the Bruggeman effective medium approximation (EMA). The relaxation times and the electrical conductivity are plot in function of temperature. The obtained electrical conductivity give significant result in good agreement to those reported by four points electrical measurement method.

  7. Molecular recognition by gold, silver and copper nanoparticles

    PubMed Central

    Tauran, Yannick; Brioude, Arnaud; Coleman, Anthony W; Rhimi, Moez; Kim, Beonjoom

    2013-01-01

    The intrinsic physical properties of the noble metal nanoparticles, which are highly sensitive to the nature of their local molecular environment, make such systems ideal for the detection of molecular recognition events. The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles. In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization. A brief discussion of the three common methods of functionalization: Electrostatic adsorption; Chemisorption; Affinity-based coordination is given. In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition. In the main section the various types of capping agents for molecular recognition; nucleic acid coatings, protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications. Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition. For the proteins the recognition properties of antibodies form the core of the section. With respect to the supramolecular systems the cyclodextrins, calix[n]arenes, dendrimers, crown ethers and the cucurbitales are treated in depth. Finally a short section deals with the possible toxicity of the nanoparticles, a concern in public health. PMID:23977421

  8. Synthesis of photoactive AgCl/SBA-15 by conversion of silver nanoparticles into stable AgCl nanoparticles

    NASA Astrophysics Data System (ADS)

    Zienkiewicz-Strza?ka, M.; Pikus, S.

    2013-01-01

    In this work the results of synthesis the ordered mesoporous silica (SBA-15) in the presence of stable silver nanoparticles were presented. It has been proven that the proposed method leads to the synthesis of SBA-15 nanocomposite containing silver chloride nanoparticles, formed by the transformation of silver nanoparticles in the acidic conditions. Proposed one-pot procedure is simple and the one requirement is to prepare a stable solution of silver nanoparticles. In this work, silver nanoparticles were obtained during chemical reduction of [Ag(NH3)2]+ ions by formaldehyde. Silver nanoparticles solution can be used as a silver chloride source due to the application of the same polymer as a stabilizer of nanocrystals and structure directing agent of SBA-15. The final AgCl/SBA-15 materials show excellent structural ordering characteristic for this type of materials confirmed by diffraction measurements in range of small angles 2?, transmission electron microscopy (TEM) and nitrogen adsorption/desorption measurements. AgCl nanoparticles were identified by diffraction measurements as chlorargyrite phase. The presence of silver nanoparticles in initial solution and their absence after synthesis were confirmed by UV-vis measurements. The photoactivity of obtained AgCl/SBA-15 composite was tested in reaction of organic impurities photodegradation.

  9. Partitioning of silver and chemical speciation of free Ag in soils amended with nanoparticles

    PubMed Central

    2013-01-01

    Background Knowledge about silver nanoparticles in soils is limited even if soils are a critical pathway for their environmental fate. In this paper, speciation results have been acquired using a silver ion selective electrode in three different soils. Results Soil organic matter and pH were the most important soil properties controlling the occurrence of silver ions in soils. In acidic soils, more free silver ions are available while in the presence of organic matter, ions were tightly bound in complexes. The evolution of the chemical speciation of the silver nanoparticles in soils was followed over six months. Conclusion During the first few hours, there appeared to be a strong sorption of the silver with soil ligands, whereas over time, silver ions were released, the final concentration being approximately 10 times higher than at the beginning. Ag release was associated with either the oxidation of the nanoparticles or a dissociation of adsorbed silver from the soil surfaces. PMID:23617903

  10. Preparation and Characterization of Gelatin Nanofibers Containing Silver Nanoparticles

    PubMed Central

    Jeong, Lim; Park, Won Ho

    2014-01-01

    Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag+ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO3)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO3/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO3 and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO3. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM). PMID:24758929

  11. Preparation and characterization of gelatin nanofibers containing silver nanoparticles.

    PubMed

    Jeong, Lim; Park, Won Ho

    2014-01-01

    Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag+ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO?)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO?/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO? and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO?. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM). PMID:24758929

  12. Biogenic Silver Nanoparticles by Gelidiella acerosa Extract and their Antifungal Effects

    PubMed Central

    Vivek, Marimuthu; Kumar, Palanisamy Senthil; Steffi, Sesurajan; Sudha, Sellappa

    2011-01-01

    The synthesis, characterization and application of biologically synthesized nanomaterials are an important aspect in nanotechnology. The present study deals with the synthesis of silver nanoparticles (Ag-NPs) using the aqueous extract of red seaweed Gelidiella acerosa as the reducing agent to study the antifungal activity. The formation of Ag-NPs was confirmed by UV-Visible Spectroscopy, X-Ray Diffraction (XRD) pattern, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The synthesized Ag-NPs was predominately spherical in shape and polydispersed. Fourier Transform Infra-Red (FT-IR) spectroscopy analysis showed that the synthesized nano-Ag was capped with bimolecular compounds which are responsible for reduction of silver ions. The antifungal effects of these nanoparticles were studied against Humicola insolens (MTCC 4520), Fusarium dimerum (MTCC 6583), Mucor indicus (MTCC 3318) and Trichoderma reesei (MTCC 3929). The present study indicates that Ag-NPs have considerable antifungal activity in comparison with standard antifungal drug, and hence further investigation for clinical applications is necessary. PMID:23408653

  13. A novel green chemical route for synthesis of silver nanoparticles using camellia sinensis.

    PubMed

    Kamal, Sarika Srinivas Kalyan; Sahoo, Prasanta Kumar; Vimala, Johnson; Premkumar, Manda; Ram, Shanker; Durai, Loganathan

    2010-12-01

    The thrust to develop environmental friendly procedures for production of Nanoparticles arises from the very fact that current nanotechnology research uses a lot of chemicals, which are potential threat to both environment and public health. Tea (Camellia Sinensis) with its rich source of polyphenolic compounds has been exploited for the reduction and capping of silver nanoparticles (Ag-NPs), making it a complete green chemical route. The reduction of Ag+ to Ag0 was observed by the color change from pale yellow to dark yellow. The reaction was followed with the help of UV-Visible spectrometer. Crystal structure was obtained by carrying out X-ray diffraction studies and it showed face centered cubic (fcc) structure. The particle size and morphology were obtained from transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) studies. An average particle size of 25 nm silver particles could be obtained using this method and the TEM and SAXS data corroborate with each other. PMID:24061881

  14. High-frequency mechanical stirring initiates anisotropic growth of seeds requisite for synthesis of asymmetric metallic nanoparticles like silver nanorods.

    PubMed

    Mahmoud, Mahmoud A; El-Sayed, Mostafa A; Gao, Jianping; Landman, Uzi

    2013-10-01

    High-speed stirring at elevated temperatures is shown to be effective in the symmetry-breaking process needed for the growth of the hard-to-synthesize silver nanorods from the polyol reduction of silver ions. This process competes with the facile formation of more symmetrical, spherical and cubic, nanoparticles. Once the seed is formed, further growth proceeds predominantly along the long axis, with a consequent increase of the particles' aspect ratio (that of the nanorod). When stirring is stopped shortly after seed formation, nanorods with a broad distribution of aspect ratios are obtained, while when the high-frequency stirring continues the distribution narrows significantly. The width of the nanorods can only be increased if the initial concentration of Ag(+) ions increases. Reducing the stirring speeds during seed formation lowers the yield of nanorods. Molecular dynamics simulations reveal that the formation of a nanometer-scale thin boundary region between a solid facet of the nanoparticle and the liquid around it, and the accommodation processes of metal (Ag) atoms transported through this boundary region from the liquid to the solid growth interface, are frustrated by sufficiently fast shear flow caused by high-frequency stirring. This arrests growth on seed facets parallel to the flow, leading, together with the preferential binding of the capping polymer to the (100) facet, to the observed growth in the (110) direction, resulting in silver nanorods capped at the ends by (111) facets and exposing (100) facets on the side walls. PMID:24053557

  15. Fast preparation of printable highly conductive polymer nanocomposites by thermal decomposition of silver carboxylate and sintering of silver nanoparticles.

    PubMed

    Zhang, Rongwei; Lin, Wei; Moon, Kyoung-sik; Wong, C P

    2010-09-01

    We show the fast preparation of printable highly conductive polymer nanocomposites for future low-cost electronics. Highly conductive polymer nanocomposites, consisting of an epoxy resin, silver flakes, and incorporated silver nanoparticles, have been prepared by fast sintering between silver flakes and the incorporated silver nanoparticles. The fast sintering is attributed to: 1) the thermal decomposition of silver carboxylate-which is present on the surface of the incorporated silver flakes-to form in situ highly reactive silver nanoparticles; 2) the surface activation of the incorporated silver nanoparticles by the removal of surface residues. As a result, polymer nanocomposites prepared at 230 °C for 5 min, at 260 °C for 10 min, and using a typical lead-free solder reflow process show electrical resistivities of 8.1×10(-5), 6.0×10(-6), and 6.3×10(-5) ? cm, respectively. The correlation between the rheological properties of the adhesive paste and the noncontact printing process has been discussed. With the optimal rheological properties, the formulated highly viscous pastes (221 mPa s at 2500 s(-1)) can be non-contact-printed into dot arrays with a radius of 130 ?m. The noncontact printable polymer nanocomposites with superior electrical conductivity and fast processing are promising for the future of printed electronics. PMID:20735013

  16. Synthesis of silver nanoparticles using A. indicum leaf extract and their antibacterial activity

    NASA Astrophysics Data System (ADS)

    Ashokkumar, S.; Ravi, S.; Kathiravan, V.; Velmurugan, S.

    2015-01-01

    Green synthesis of silver nanoparticles has been achieved using environmentally acceptable plant extract. It is observed that Abutilon indicum leaf extract can reduce silver ions into silver nanoparticles within 15 min of reaction time. The formation and stability of the reduced silver nanoparticles in the colloidal solution were monitored by UV-Vis spectrophotometer analysis. The mean particle diameter of silver nanoparticles was calculated from the XRD pattern. FT-IR spectra of the leaf extract after the development of nanoparticles are determined to allow identification of possible functional groups responsible for the conversion of metal ions to metal nanoparticles. The AgNPs thus obtained showed highly potent antibacterial activity toward Gram-positive (Staphyloccocus aureus and Bacillus subtilis) and Gram-negative (Salmonella typhi and Escherichia coli) microorganisms.

  17. Synthesis of silver nanoparticles using A. indicum leaf extract and their antibacterial activity.

    PubMed

    Ashokkumar, S; Ravi, S; Kathiravan, V; Velmurugan, S

    2015-01-01

    Green synthesis of silver nanoparticles has been achieved using environmentally acceptable plant extract. It is observed that Abutilon indicum leaf extract can reduce silver ions into silver nanoparticles within 15 min of reaction time. The formation and stability of the reduced silver nanoparticles in the colloidal solution were monitored by UV-Vis spectrophotometer analysis. The mean particle diameter of silver nanoparticles was calculated from the XRD pattern. FT-IR spectra of the leaf extract after the development of nanoparticles are determined to allow identification of possible functional groups responsible for the conversion of metal ions to metal nanoparticles. The AgNPs thus obtained showed highly potent antibacterial activity toward Gram-positive (Staphyloccocus aureus and Bacillus subtilis) and Gram-negative (Salmonella typhi and Escherichia coli) microorganisms. PMID:24997264

  18. Synthesis and anti-fungal effect of silver nanoparticles–chitosan composite particles

    PubMed Central

    Wang, Lung-Shuo; Wang, Chih-Yu; Yang, Chih-Hui; Hsieh, Chen-Ling; Chen, Szu-Yu; Shen, Chi-Yen; Wang, Jia-Jung; Huang, Keng-Shiang

    2015-01-01

    Silver nanoparticles have been used in various fields, and several synthesis processes have been developed. The stability and dispersion of the synthesized nanoparticles is vital. The present article describes a novel approach for one-step synthesis of silver nanoparticles–embedded chitosan particles. The proposed approach was applied to simultaneously obtain and stabilize silver nanoparticles in a chitosan polymer matrix in-situ. The diameter of the synthesized chitosan composite particles ranged from 1.7 mm to 2.5 mm, and the embedded silver nanoparticles were measured to be 15±3.3 nm. Further, the analyses of ultraviolet-visible spectroscopy, energy dispersive spectroscopy, and X-ray diffraction were employed to characterize the prepared composites. The results show that the silver nanoparticles were distributed over the surface and interior of the chitosan spheres. The fabricated spheres had macroporous property, and could be used for many applications such as fungicidal agents in the future. PMID:25878501

  19. Caging antimicrobial silver nanoparticles inside cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, a stable, non-leaching Ag-cotton nanocomposite fiber has been characterized. Siver nanoparticles (Ag NPs) were previously synthesized in the alkali-swollen substructure of cotton fiber; the nano-sized micofibrillar channels allowed diffusion-controlled conditions to produce mono-dispe...

  20. The bactericidal effect of silver nanoparticles

    Microsoft Academic Search

    Jose Ruben Morones; Jose Luis Elechiguerra; Alejandra Camacho; Katherine Holt; Juan B. Kouri; Jose Tapia Ramírez; Miguel Jose Yacaman

    2005-01-01

    Nanotechnology is expected to open new avenues to fight and prevent disease using atomic scale tailoring of materials. Among the most promising nanomaterials with antibacterial properties are metallic nanoparticles, which exhibit increased chemical activity due to their large surface to volume ratios and crystallographic surface structure. The study of bactericidal nanomaterials is particularly timely considering the recent increase of new

  1. Silver confined within zeolite EMT nanoparticles: preparation and antibacterial properties

    NASA Astrophysics Data System (ADS)

    Dong, B.; Belkhair, S.; Zaarour, M.; Fisher, L.; Verran, J.; Tosheva, L.; Retoux, R.; Gilson, J.-P.; Mintova, S.

    2014-08-01

    The preparation of pure zeolite nanocrystals (EMT-type framework) and their silver ion-exchanged (Ag+-EMT) and reduced silver (Ag0-EMT) forms is reported. The template-free zeolite nanocrystals are stabilized in water suspensions and used directly for silver ion-exchange and subsequent chemical reduction under microwave irradiation. The high porosity, low Si/Al ratio, high concentration of sodium and ultrasmall crystal size of the EMT-type zeolite permitted the introduction of a high amount of silver using short ion-exchange times in the range of 2-6 h. The killing efficacy of pure EMT, Ag+-EMT and Ag0-EMT against Escherichia coli was studied semi-quantitatively. The antibacterial activity increased with increasing Ag content for both types of samples (Ag+-EMT and Ag0-EMT). The Ag0-EMT samples show slightly enhanced antimicrobial efficacy compared to that of Ag+-EMT, however, the differences are not substantial and the preparation of Ag nanoparticles is not viable considering the complexity of preparation steps.The preparation of pure zeolite nanocrystals (EMT-type framework) and their silver ion-exchanged (Ag+-EMT) and reduced silver (Ag0-EMT) forms is reported. The template-free zeolite nanocrystals are stabilized in water suspensions and used directly for silver ion-exchange and subsequent chemical reduction under microwave irradiation. The high porosity, low Si/Al ratio, high concentration of sodium and ultrasmall crystal size of the EMT-type zeolite permitted the introduction of a high amount of silver using short ion-exchange times in the range of 2-6 h. The killing efficacy of pure EMT, Ag+-EMT and Ag0-EMT against Escherichia coli was studied semi-quantitatively. The antibacterial activity increased with increasing Ag content for both types of samples (Ag+-EMT and Ag0-EMT). The Ag0-EMT samples show slightly enhanced antimicrobial efficacy compared to that of Ag+-EMT, however, the differences are not substantial and the preparation of Ag nanoparticles is not viable considering the complexity of preparation steps. Electronic supplementary information (ESI) available: Zeta potential data of Ag-EMT suspensions, pore-size distributions and antibacterial data for Ag-EMT 2 h samples. See DOI: 10.1039/c4nr03169e

  2. Influence of gold, silver and gold–silver alloy nanoparticles on germ cell function and embryo development

    PubMed Central

    Rehbock, Christoph; Kues, Wilfried A

    2015-01-01

    Summary The use of engineered nanoparticles has risen exponentially over the last decade. Applications are manifold and include utilisation in industrial goods as well as medical and consumer products. Gold and silver nanoparticles play an important role in the current increase of nanoparticle usage. However, our understanding concerning possible side effects of this increased exposure to particles, which are frequently in the same size regime as medium sized biomolecules and accessorily possess highly active surfaces, is still incomplete. That particularly applies to reproductive aspects, were defects can be passed onto following generations. This review gives a brief overview of the most recent findings concerning reprotoxicological effects. The here presented data elucidate how composition, size and surface modification of nanoparticles influence viablility and functionality of reproduction relevant cells derived from various animal models. While in vitro cultured embryos displayed no toxic effects after the microinjection of gold and silver nanoparticles, sperm fertility parameters deteriorated after co-incubation with ligand free gold nanoparticles. However, the effect could be alleviated by bio-coating the nanoparticles, which even applies to silver and silver-rich alloy nanoparticles. The most sensitive test system appeared to be in vitro oocyte maturation showing a dose-dependent response towards protein (BSA) coated gold–silver alloy and silver nanoparticles leading up to complete arrest of maturation. Recent biodistribution studies confirmed that nanoparticles gain access to the ovaries and also penetrate the blood–testis and placental barrier. Thus, the design of nanoparticles with increased biosafety is highly relevant for biomedical applications. PMID:25821705

  3. Facile chemical synthesis of nano-silver powders for printable electronics applications

    Microsoft Academic Search

    P. K. Sahoo; S. S. Kalyan Kamal; B. Shankar; B. Sreedhar; L. Durai

    2012-01-01

    In this article, a simple and reproducible technique for the synthesis of silver nanoparticles in organic phase without using external reducing agents is reported. The organic phase contains silver acetate as precursor, oleic acid and oleyl amine as capping molecules and diphenyl ether as solvent. Monodispersed silver nanoparticles with an average size of 5?nm could be easily synthesised at large

  4. L-Phenylalanine functionalized silver nanoparticles: Photocatalytic and nonlinear optical applications

    NASA Astrophysics Data System (ADS)

    Nidya, M.; Umadevi, M.; Sankar, Pranitha; Philip, Reji; Rajkumar, Beulah J. M.

    2015-04-01

    An extensive study on the behavior of L-Phenylalanine capped silver nanoparticles (Phe-Ag NPs) in the aqueous phase and in a sol-gel thin film showed different UV/Vis, Transmission Electron Microscope (TEM), Dynamic Light Scattering and Zeta potential profiles. Scanning Electron Microscope (SEM) images of the samples in the sol gel film showed Ag embedded in the SiO2 matrix. Surface Enhanced Raman Spectra (SERS) confirmed that both in the aqueous media and in the sol gel film, the attachment of Phe to the Ag NP surface was through the benzene ring, with the sol-gel film showing a better enhancement. Photocatalytic degradation of crystal violet was measured spectrophotometrically using Phe-Ag NPs as a nanocatalyst under visible light illumination. Intensity-dependent nonlinear optical absorption of Phe-Ag measured using the open aperture Z-scan technique revealed that the material is an efficient optical limiter with potential applications.

  5. Antibacterial applications of silver nanoparticles synthesized by aqueous extract of Azadirachta indica (Neem) leaves.

    PubMed

    Tripathi, A; Chandrasekaran, N; Raichur, A M; Mukherjee, A

    2009-02-01

    Silver nanoparticles are known to have bactericidal effects. A new generation of dressings incorporating antimicrobial agents like silver nanoparticles is being formulated to reduce or prevent infections. The particles can be incorporated in materials and cloth rendering them sterile. Recently, it was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Apart from being environmentally friendly process, use of Neem leaves extract might add synergistic antibacterial effect of Neem leaves to the biosynthesized nanoparticles. With this hypothesis the biosynthetic production of silver nanoparticles by aqueous extract of Neem leaves and its bactericidal effect in cotton cloth against E. Coli were studied in this work. Silver nanoparticles were synthesized by short-term (1 day) and long-term (21 days) interaction of Neem extract (20% w/v) and 0.01 M AgNO3 solution in 1:4 mixing ratio. The synthesized particles were characterized by UV visible spectroscopy, transmission electron microscopy, and incorporated into cotton disks by (i) centrifuging the disks with liquid broth containing nanoparticles, (ii) in-situ coating process during synthesis, and (iii) coating with dried and purified nanoparticles. The antibacterial property of the nanoparticles coated cotton disks was studied by disk diffusion method. The effect of consecutive washing of the coated disks with distilled water on antibacterial property was also investigated. This work demonstrates the possible use of biologically synthesized silver nanoparticles by its incorporation in cloths leading them to sterilization. PMID:20055111

  6. Screening of cyanobacterial extracts for synthesis of silver nanoparticles.

    PubMed

    Husain, Shaheen; Sardar, Meryam; Fatma, Tasneem

    2015-08-01

    Improvement of reliable and eco-friendly process for synthesis of metallic nanoparticles is a significant step in the field of application nanotechnology. One approach that shows vast potential is based on the biosynthesis of nanoparticles using micro-organisms. In this study, biosynthesis of silver nanoparticles (AgNP) using 30 cyanobacteria were investigated. Cyanobacterial aqueous extracts were subjected to AgNP synthesis at 30 °C. Scanning of these aqueous extracts containing AgNP in UV-Visible range showed single peak. The ? max for different extracts varied and ranged between 440 and 490 nm that correspond to the "plasmon absorbance" of AgNP. Micrographs from scanning electron microscope of AgNP from cyanobacterial extracts showed that though synthesis of nanoparticles occurred in all strains but their reaction time, shape and size varied. Majority of the nanoparticles were spherical. Time taken for induction of nanoparticles synthesis by cyanobacterial extracts ranged from 30 to 360 h and their size from 38 to 88 nm. In terms of size Cylindrospermum stagnale NCCU-104 was the best organism with 38 and 40 nm. But in terms of time Microcheate sp. NCCU-342 was the best organism as it took 30 h for AgNP synthesis. PMID:25971548

  7. Reversible transformations of silver oxide and metallic silver nanoparticles inside SiO{sub 2} films

    SciTech Connect

    Pal, Sudipto [Sol-Gel Division, Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Jadavpur, Kolkata 700032 (India); De, Goutam [Sol-Gel Division, Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Jadavpur, Kolkata 700032 (India)], E-mail: gde@cgcri.res.in

    2009-02-04

    Reversible transformation of silver oxide and metallic nanoparticles inside a relatively porous silica film has been established. Annealing of Ag-doped films in oxidizing (air) atmosphere at 450 deg. C yielded colorless films containing AgO{sub x}. These films were turned yellow when heated in H{sub 2}-N{sub 2} (reducing atmosphere) due to the formation of Ag nanoparticles. This yellow coloration (due to nano Ag{sup 0}) and bleaching (conversion of Ag{sup 0} {yields} Ag{sup +}) are reversible. Optical and photoluminescence spectra are well consistent with this coloration and bleaching. The soaking test of the air-annealed film in Na{sub 2}S{sub 2}O{sub 3} solution supports the presence of Ag{sup +}. Grazing incidence X-ray diffraction and transmission electron microscopy studies reveal the formation of Ag-oxides and Ag nanoparticles in the oxidized and reduced films, respectively.

  8. Tunable morphological properties of silver enriched platinum allied nanoparticles and their catalysed reduction of p-nitrophenol

    NASA Astrophysics Data System (ADS)

    Adeyemi Adekoya, Joseph; Olugbenga Dare, Enock; Adediran Mesubi, Michael

    2014-09-01

    A robust polymer based and polyol mediated procedure to synthesize nanobimetallic particles has been modified to produce core–shell and alloy Ag/Pt nanoparticles with tunable properties. Novel three-dimensional (3D) quasi nanocubes entangled in nanowebs were produced by rapid solution phase transformation with hot addition of absolute ethanol. The optical characterization showed extinction of plasmon resonance band occurring with incremental feeding ratio of Pt source in all cases. Transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) images revealed that the shape, size and size distribution of as-prepared silver platinum nanoparticles depended on the stabilizer or capping agent, mole ratio of metal ion sources, temperature and time of reaction. Meanwhile, catalytic activity was highest in the reduction of p-nitrophenol in the presence of polyvinylpyrrolidone/diethylene glycol stabilized Ag/Pt nanoparticles.

  9. Surface-independent antibacterial coating using silver nanoparticle-generating engineered mussel glue.

    PubMed

    Jo, Yun Kee; Seo, Jeong Hyun; Choi, Bong-Hyuk; Kim, Bum Jin; Shin, Hwa Hui; Hwang, Byeong Hee; Cha, Hyung Joon

    2014-11-26

    During implant surgeries, antibacterial agents are needed to prevent bacterial infections, which can cause the formation of biofilms between implanted materials and tissue. Mussel adhesive proteins (MAPs) derived from marine mussels are bioadhesives that show strong adhesion and coating ability on various surfaces even in wet environment. Here, we proposed a novel surface-independent antibacterial coating strategy based on the fusion of MAP to a silver-binding peptide, which can synthesize silver nanoparticles having broad antibacterial activity. This sticky recombinant fusion protein enabled the efficient coating on target surface and the easy generation of silver nanoparticles on the coated-surface under mild condition. The biosynthesized silver nanoparticles showed excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria and also revealed good cytocompatibility with mammalian cells. In this coating strategy, MAP-silver binding peptide fusion proteins provide hybrid environment incorporating inorganic silver nanoparticle and simultaneously mediate the interaction of silver nanoparticle with surroundings. Moreover, the silver nanoparticles were fully synthesized on various surfaces including metal, plastic, and glass by a simple, surface-independent coating manner, and they were also successfully synthesized on a nanofiber surface fabricated by electrospinning of the fusion protein. Thus, this facile surface-independent silver nanoparticle-generating antibacterial coating has great potential to be used for the prevention of bacterial infection in diverse biomedical fields. PMID:25311392

  10. Thermal cure effects on electrical performance of nanoparticle silver inks Julia R. Greer *, Robert A. Street

    E-print Network

    Greer, Julia R.

    . 2. Experimental results 2.1. Materials and measurements The specific silver nano-ink used in this work consists of $40 nm silver particles with $5 nm polymer coating in an organic solvent. In ourThermal cure effects on electrical performance of nanoparticle silver inks Julia R. Greer *, Robert

  11. Influence of silver nano-particles on monomer elution from light-cured composites

    Microsoft Academic Search

    Jürgen Durner; Marija Stojanovic; Ebru Urcan; Reinhard Hickel; Franx-Xaver Reichl

    2011-01-01

    ObjectivesSilver containing materials have been used for years as antimicrobial materials. Silver particles were also added to experimental dental composites to reduce caries. The aim of our study was to show whether silver nanoparticles can lead to higher amounts of elutable substances.

  12. Method of Creating Micro-scale Silver Telluride Grains Covered with Bismuth Nanoparticles

    NASA Technical Reports Server (NTRS)

    Kim, Hyun-Jung (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Park, Yeonjoon (Inventor); Lee, Kunik (Inventor)

    2014-01-01

    Provided is a method of enhancing thermoelectric performance by surrounding crystalline semiconductors with nanoparticles by contacting a bismuth telluride material with a silver salt under a substantially inert atmosphere and a temperature approximately near the silver salt decomposition temperature; and recovering a metallic bismuth decorated material comprising silver telluride crystal grains.

  13. Ultrastructural Analysis of Candida albicans When Exposed to Silver Nanoparticles

    PubMed Central

    Vazquez-Muñoz, Roberto; Avalos-Borja, Miguel; Castro-Longoria, Ernestina

    2014-01-01

    Candida albicans is the most common fungal pathogen in humans, and recently some studies have reported the antifungal activity of silver nanoparticles (AgNPs) against some Candida species. However, ultrastructural analyses on the interaction of AgNPs with these microorganisms have not been reported. In this work we evaluated the effect of AgNPs on C. albicans, and the minimum inhibitory concentration (MIC) was found to have a fungicidal effect. The IC50 was also determined, and the use of AgNPs with fluconazole (FLC), a fungistatic drug, reduced cell proliferation. In order to understand how AgNPs interact with living cells, the ultrastructural distribution of AgNPs in this fungus was determined. Transmission electron microscopy (TEM) analysis revealed a high accumulation of AgNPs outside the cells but also smaller nanoparticles (NPs) localized throughout the cytoplasm. Energy dispersive spectroscopy (EDS) analysis confirmed the presence of intracellular silver. From our results it is assumed that AgNPs used in this study do not penetrate the cell, but instead release silver ions that infiltrate into the cell leading to the formation of NPs through reduction by organic compounds present in the cell wall and cytoplasm. PMID:25290909

  14. Specific biomolecule corona is associated with ring-shaped organization of silver nanoparticles in cells

    NASA Astrophysics Data System (ADS)

    Drescher, Daniela; Guttmann, Peter; Büchner, Tina; Werner, Stephan; Laube, Gregor; Hornemann, Andrea; Tarek, Basel; Schneider, Gerd; Kneipp, Janina

    2013-09-01

    We correlate the localization of silver nanoparticles inside cells with respect to the cellular architecture with the molecular information in the vicinity of the particle surface by combining nanoscale 3D cryo-soft X-ray tomography (cryo-SXT) with surface-enhanced Raman scattering (SERS). The interaction of the silver nanoparticle surface with small molecules and biopolymers was monitored by SERS in vitro over time in living cells. The spectra indicate a stable, time-independent surface composition of silver nanoparticles, despite the changing environment in the endosomal structure. Cryo-SXT reveals a characteristic ring-shaped organization of the silver nanoparticles in endosomes of different cell types. The ring-like structures inside the endosomes suggest a strong association among silver particles and with membrane structures. The comparison of the data with those obtained with gold nanoparticles suggests that the interactions between the nanoparticles and with the endosomal component are influenced by the molecular composition of the corona.We correlate the localization of silver nanoparticles inside cells with respect to the cellular architecture with the molecular information in the vicinity of the particle surface by combining nanoscale 3D cryo-soft X-ray tomography (cryo-SXT) with surface-enhanced Raman scattering (SERS). The interaction of the silver nanoparticle surface with small molecules and biopolymers was monitored by SERS in vitro over time in living cells. The spectra indicate a stable, time-independent surface composition of silver nanoparticles, despite the changing environment in the endosomal structure. Cryo-SXT reveals a characteristic ring-shaped organization of the silver nanoparticles in endosomes of different cell types. The ring-like structures inside the endosomes suggest a strong association among silver particles and with membrane structures. The comparison of the data with those obtained with gold nanoparticles suggests that the interactions between the nanoparticles and with the endosomal component are influenced by the molecular composition of the corona. Electronic supplementary information (ESI) available: Description of additional experiments. Explanation of transmitted intensity and linear absorption coefficient in a cryo-XRT experiment (Fig. S1 and S2). Additional X-ray data (Fig. S3 and Movie S1). Toxicity of silver nanoparticles (Fig. S4). X-ray microscopy and SERS experiments with gold nanoparticles (Fig. S5 and S6). Size, plasmonic properties, and stability of silver and gold nanoparticles (Fig. S7-S9). Distribution of the silver nanoparticles in the cells using SERS mapping (Fig. S10). Tentative band assignments (Table S1). See DOI: 10.1039/c3nr02129g

  15. PVP capped CdS nanoparticles for UV-LED applications

    NASA Astrophysics Data System (ADS)

    Sivaram, H.; Selvakumar, D.; Jayavel, R.

    2015-06-01

    Polyvinlypyrrolidone (PVP) capped cadmium sulphide (CdS) nanoparticles are synthesized by wet chemical method. The powder X-ray diffraction (XRD) result indicates that the nanoparticles are crystallized in cubic phase. The optical properties are characterized by UV-Vis absorption. The morphology of CdS nanoparticles are studied using Scanning electron microscope (SEM). The thermal behavior of the as prepared nanoparticles has been examined by Thermo gravimetric analysis (TGA). The optical absorption study of pvp capped CdS reveal a red shift confirms the UV-LED applications.

  16. NANO EXPRESS Open Access H2-induced copper and silver nanoparticle

    E-print Network

    Paris-Sud XI, Université de

    NANO EXPRESS Open Access H2-induced copper and silver nanoparticle precipitation inside sol nanoparticles with diameters in the range of 3 to 6 nm and nano-rods were obtained. Keywords: copper Bernard, Christophe Kinowski, Mohamed Bouazaoui* and Bruno Capoen Abstract Ionic copper- or silver

  17. Optimization of Surface Plasmon Excitation Using Resonant Nanoparticle Arrays above a Silver Film

    E-print Network

    Kik, Pieter

    Optimization of Surface Plasmon Excitation Using Resonant Nanoparticle Arrays above a Silver Film above the silver film, the array-mediated surface plasmon excitation is studied. Finite Integration enhanced fields near the nanoparticles, which in turn excite surface plasmons on the metal film

  18. Silver nanoparticles decrease body weight and locomotor activity in adult male rats.

    PubMed

    Zhang, Yongbin; Ferguson, Sherry A; Watanabe, Fumiya; Jones, Yvonne; Xu, Yang; Biris, Alexandru S; Hussain, Saber; Ali, Syed F

    2013-05-27

    Silver nanoparticles (Ag-NPs) are widely used in FDA regulated products. The physical-chemical properties of Ag-NPs are characterized using various instruments. The dose-dependent activity and body weight alterations are evaluated after rats were exposed to Ag nanoparticles, suggesting a major human health risk, given the wide application of silver nanomaterials. PMID:23335405

  19. A high-throughput and selective method for the measurement of surface areas of silver nanoparticles.

    PubMed

    Agustin, Yuana Elly; Tsai, Shen-Long

    2015-04-21

    A high-throughput and selective method based on biomolecule affinity coordination was employed for measuring nanoparticle surface area in solutions. In this design, silver binding peptides (AgBPs) are immobilized on bacterial cellulose via fusion with cellulose binding domains to capture silver nanoparticles whereas green fluorescent proteins are fused with AgBPs as reporters for surface area quantification. PMID:25713816

  20. Stability of colloidal silver nanoparticles trapped in lipid bilayer: effect of lecithin concentration and applied temperature.

    PubMed

    Barani, Hossein; Montazer, Majid; Braun, Hans-Georg; Dutschk, Victoria

    2014-12-01

    The use of silver nanoparticle on various substrates has been widespread because of its good antibacterial properties that directly depend on the stability of the silver nanoparticles in a colloidal suspension. In this study, the colloidal solutions of the silver nanoparticles were synthesised by a simple and safe method by using lecithin as a stabilising agent and their stability was examined at various temperatures. The effect of the lecithin concentrations on the stability of the synthesised silver nanoparticles was examined from 25 to 80°C at 5°C intervals, by recording the changes in the UV-vis absorption spectra, the hydrodynamic diameter and the light scattering intensity of the silver nanoparticles. In addition, the morphology of the synthesised silver nanoparticles was investigated with the low-voltage scanning electron microscopy and transmission electron microscopy. The results indicated that increasing temperature caused different changes in the size of the stabilised and the unstabilised silver nanoparticles. The size of the stabilised silver nanoparticles reduced from 38 to 36 nm during increasing temperature, which confirmed good stability. PMID:25429509

  1. Silver nanoparticle-doped zirconia capillaries for enhanced bacterial filtration.

    PubMed

    Wehling, Julia; Köser, Jan; Lindner, Patrick; Lüder, Christian; Beutel, Sascha; Kroll, Stephen; Rezwan, Kurosch

    2015-03-01

    Membrane clogging and biofilm formation are the most serious problems during water filtration. Silver nanoparticle (Agnano) coatings on filtration membranes can prevent bacterial adhesion and the initiation of biofilm formation. In this study, Agnano are immobilized via direct reduction on porous zirconia capillary membranes to generate a nanocomposite material combining the advantages of ceramics being chemically, thermally and mechanically stable with nanosilver, an efficient broadband bactericide for water decontamination. The filtration of bacterial suspensions of the fecal contaminant Escherichia coli reveals highly efficient bacterial retention capacities of the capillaries of 8 log reduction values, fulfilling the requirements on safe drinking water according to the U.S. Environmental Protection Agency. Maximum bacterial loading capacities of the capillary membranes are determined to be 3×10(9)bacterialcells/750mm(2) capillary surface until back flushing is recommendable. The immobilized Agnano remain accessible and exhibit strong bactericidal properties by killing retained bacteria up to maximum bacterial loads of 6×10(8)bacterialcells/750mm(2) capillary surface and the regenerated membranes regain filtration efficiencies of 95-100%. Silver release is moderate as only 0.8% of the initial silver loading is leached during a three-day filtration experiment leading to average silver contaminant levels of 100?g/L. PMID:25579912

  2. Low-cost silver capped polystyrene nanotube arrays as super-hydrophobic substrates for SERS applications.

    PubMed

    Lovera, Pierre; Creedon, Niamh; Alatawi, Hanan; Mitchell, Micki; Burke, Micheal; Quinn, Aidan J; O'Riordan, Alan

    2014-05-01

    In this paper, we describe the fabrication, simulation and characterization of dense arrays of freestanding silver capped polystyrene nanotubes, and demonstrate their suitability for surface enhanced Raman scattering (SERS) applications. Substrates are fabricated in a rapid, low-cost and scalable way by melt wetting of polystyrene (PS) in an anodized alumina (AAO) template, followed by silver evaporation. Scanning electron microscopy reveals that substrates are composed of a dense array of freestanding polystyrene nanotubes topped by silver nanocaps. SERS characterization of the substrates, employing a monolayer of 4-aminothiophenol (4-ABT) as a model molecule, exhibits an enhancement factor of ?1.6 × 10(6), in agreement with 3D finite difference time domain simulations. Contact angle measurements of the substrates revealed super-hydrophobic properties, allowing pre-concentration of target analyte into a small volume. These super-hydrophobic properties of the samples are taken advantage of for sensitive detection of the organic pollutant crystal violet, with detection down to ?400 ppt in a 2 ?l aliquot demonstrated. PMID:24717806

  3. Low-cost silver capped polystyrene nanotube arrays as super-hydrophobic substrates for SERS applications

    NASA Astrophysics Data System (ADS)

    Lovera, Pierre; Creedon, Niamh; Alatawi, Hanan; Mitchell, Micki; Burke, Micheal; Quinn, Aidan J.; O'Riordan, Alan

    2014-05-01

    In this paper, we describe the fabrication, simulation and characterization of dense arrays of freestanding silver capped polystyrene nanotubes, and demonstrate their suitability for surface enhanced Raman scattering (SERS) applications. Substrates are fabricated in a rapid, low-cost and scalable way by melt wetting of polystyrene (PS) in an anodized alumina (AAO) template, followed by silver evaporation. Scanning electron microscopy reveals that substrates are composed of a dense array of freestanding polystyrene nanotubes topped by silver nanocaps. SERS characterization of the substrates, employing a monolayer of 4-aminothiophenol (4-ABT) as a model molecule, exhibits an enhancement factor of ˜1.6 × 106, in agreement with 3D finite difference time domain simulations. Contact angle measurements of the substrates revealed super-hydrophobic properties, allowing pre-concentration of target analyte into a small volume. These super-hydrophobic properties of the samples are taken advantage of for sensitive detection of the organic pollutant crystal violet, with detection down to ˜400 ppt in a 2 ?l aliquot demonstrated.

  4. Characterization of cap-shaped silver particles for surface-enhanced fluorescence effects.

    PubMed

    Yamaguchi, Tetsuji; Kaya, Takatoshi; Takei, Hiroyuki

    2007-05-15

    Surface-enhanced fluorescence has potentially many desirable properties as an analytical method for medical diagnostics, but the effect observed so far is rather modest and only in conjunction with fluorophores with low quantum yields. Coupled with the fact that preparation of suitable surfaces at low costs has been difficult, this has limited its utilities. Here we report a novel method for forming uniform and reproducible surfaces with respectable enhancement ratios even for high-quantum-yield fluorophores. Formation of dense surface-adsorbed latex spheres on a flat surface via partial aggregation, followed by evaporation of silver, results in a film consisting of cap-shaped silver particles at high densities. Binding of fluorescence biomolecules, either through physisorption or antigen-antibody reaction, was performed, and enhancements close to 50 have been observed with fluorophores such as R-phycoerythrin and Alexa 546-labeled, bovine serum albumin, both of which have quantum yields around 0.8. We attribute this to the unique shape of the silver particle and the presence of abundant gaps among adjacent particles at high densities. The effectiveness of the new surface is also demonstrated with IL-6 sandwich assays. PMID:17400167

  5. Synthesis of silver nanoparticles by silver salt reduction and its characterization

    NASA Astrophysics Data System (ADS)

    Muzamil, Muhammad; Khalid, Naveed; Danish Aziz, M.; Aun Abbas, S.

    2014-06-01

    The wet chemical method route by metal salt reduction has been used to synthesize nanoparticles, using silver nitrate as an inorganic salt, aldehyde as a reducing agent and amino acid as a catalyst. During the reaction aldehyde oxidizes to carboxylic acid and encapsulates the silver nanoparticles to prevent agglomeration and provide barrier in the growth of particle. The existing work produces particles using lab grade chemical, here the presented work is by using industrial grade chemicals to make the process more cost & time effective. The nano silver powder has been studied for their formation, particle size, shape & compositional analysis using Scanning Electron Microscope (SEM) equipped with EDS. The particles size distributions were analyzed by Laser Particle Analyzer (LPA), structure & morphological analysis using x-ray diffraction (XRD) and Fourier-transform-infrared Spectroscopy (FTIR) confirmed the stabilization of particles by coating of carboxylic group. These studies infer that the particles are mostly spherical in shape and have an average size between 70 to 350 nm.

  6. Retention and transport of silver nanoparticles in a ceramic porous medium used for point-of-use water treatment.

    PubMed

    Ren, Dianjun; Smith, James A

    2013-04-16

    The retention and transport of silver nanoparticles (Ag-NPs) through a ceramic porous medium used for point-of-use drinking water purification is investigated. Two general types of experiments were performed: (i) pulse injections of suspensions of Ag-NPs in aqueous MgSO4 solutions were applied to the ceramic medium, and effluent silver was quantified over time; (ii) Ag-NPs were applied directly to the porous medium during fabrication using a paint-on, dipping, or fire-in method, a synthetic, moderately hard water sample with monovalent and divalent inorganic ions was applied to the ceramic medium, and effluent silver was quantified over time. These latter experiments were performed to approximate real-world use of the filter medium. For experiments with Ag-NPs suspended in the inflow solution, the percentage of applied Ag-NPs retained in the ceramic porous medium ranged from about 13 to 100%. Ag-NP mobility decreased with increasing ionic strength for all cases and to a lesser extent with increasing nanoparticle diameter. Citrate-capped particles were slightly less mobile than proteinate-capped particles. For ceramic disks fabricated with Ag-NPs by the paint-on and dipping methods (where the Ag-NPs are applied to the disks after firing), significant release of nanoparticles into the filter disk effluent was observed relative to the fire-in method (where the nanoparticles are combined with the clay, water, grog, and flour before firing). These results suggest that the fire-in method may be a new and significant improvement to ceramic filter design. PMID:23496137

  7. Fabrication Of Biogenic Silver Nanoparticles Using Agricultural Crop Plant Leaf Extracts

    NASA Astrophysics Data System (ADS)

    Rajani, P.; SriSindhura, K.; Prasad, T. N. V. K. V.; Hussain, O. M.; Sudhakar, P.; Latha, P.; Balakrishna, M.; Kambala, V.; Reddy, K. Raja

    2010-10-01

    Nanoparticles are being viewed as fundamental building blocks of nanotechnology. Biosynthesis of nanoparticles by plant extracts is currently under exploitation. Use of agricultural crop plant extracts for synthesis of metal nanoparticles would add a new dimension to the agricultural sector in the utilization of crop waste. Silver has long been recognized as having an inhibitory effect towards many bacterial strains and microorganisms commonly present in medical and industrial processes. Four pulse crop plants and three cereal crop plants (Vigna radiata, Arachis hypogaea, Cyamopsis tetragonolobus, Zea mays, Pennisetum glaucum, Sorghum vulgare) were used and compared for their extra cellular synthesis of metallic silver nanoparticles. Stable silver nanoparticles were formed by treating aqueous solution of AgNO3 with the plant leaf extracts as reducing agent at temperatures 50 °C-95 °C. UV-Visible spectroscopy was utilized to monitor the formation of silver nanoparticles. XRD analysis of formed silver nanoparticles revealed face centered cubic structure with (111), (200), (220) and (311) planes. SEM and EDAX analysis confirm the size of the formed silver nanoparticles to be in the range of 50-200 nm. Our proposed work offers a enviro-friendly method for biogenic silver nanoparticles production. This could provide a faster synthesis rate comparable to those of chemical methods and potentially be used in areas such as cosmetics, food and medical applications.

  8. Silver nanoparticles: mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects

    NASA Astrophysics Data System (ADS)

    Prabhu, Sukumaran; Poulose, Eldho K.

    2012-10-01

    Silver nanoparticles are nanoparticles of silver which are in the range of 1 and 100 nm in size. Silver nanoparticles have unique properties which help in molecular diagnostics, in therapies, as well as in devices that are used in several medical procedures. The major methods used for silver nanoparticle synthesis are the physical and chemical methods. The problem with the chemical and physical methods is that the synthesis is expensive and can also have toxic substances absorbed onto them. To overcome this, the biological method provides a feasible alternative. The major biological systems involved in this are bacteria, fungi, and plant extracts. The major applications of silver nanoparticles in the medical field include diagnostic applications and therapeutic applications. In most of the therapeutic applications, it is the antimicrobial property that is being majorly explored, though the anti-inflammatory property has its fair share of applications. Though silver nanoparticles are rampantly used in many medical procedures and devices as well as in various biological fields, they have their drawbacks due to nanotoxicity. This review provides a comprehensive view on the mechanism of action, production, applications in the medical field, and the health and environmental concerns that are allegedly caused due to these nanoparticles. The focus is on effective and efficient synthesis of silver nanoparticles while exploring their various prospective applications besides trying to understand the current scenario in the debates on the toxicity concerns these nanoparticles pose.

  9. Green Synthesis of Silver Nanoparticles Using Neem Leaf (Azadirachta indica) Extract

    NASA Astrophysics Data System (ADS)

    Shukla, Vineet Kumar; Pandey, Shipra; Pandey, Avinash C.

    2010-10-01

    Silver nanoparticles were successfully synthesized using crude neem leaf (Azadirachta indica) extract at room temperature. The formation and crystallinity of synthesized silver nanoparticles was confirmed by X-Ray diffraction (XRD) pattern. The average size of these silver nanoparticles is about 20-50 nm as observed by Transmission electron microscopy (TEM) images. Optical absorption measurements were performed to determine band-edge energy gap of these silver nanoparticles. Photoluminescence (PL) studies were performed to emphasize its emission properties. The synthesized silver nanoparticles could have major applications in the area of nanoscale optoelectronics devices and biomedical engineering. Our synthesis method has advantage over other conventional chemical routes because it is cost effective & environmental compatibility.

  10. Biosynthesis of Silver Nanoparticles from Marine Seaweed Sargassum cinereum and their Antibacterial Activity

    PubMed Central

    Mohandass, C.; Vijayaraj, A. S.; Rajasabapathy, R.; Satheeshbabu, S.; Rao, S. V.; Shiva, C.; De-Mello, I.

    2013-01-01

    Seaweed extracts of Sargassum cinereum was used as a reducing agent in the eco-friendly extracellular synthesis of silver nanoparticles from an aqueous solution of silver nitrate (AgNO3). High conversion of silver ions to silver nanoparticles was achieved with a reaction temperature of 100° and a seaweed extract concentration of 10% with a residential time of 3 h. Formation of silver nanoparticles was characterised by spectrophotometry and the scanning electron microscope. The average particles size was ranging from 45 to 76 nm. Antimicrobial activities indicate the minimum inhibitory concentration of biologically synthesised nanoparticles tested against the pathogen Staphylococcus aureus with 2.5 ?l (25 ?g/disc). High inhibitions over the growth of Enterobacter aerogenes, Salmonella typhi and Proteus vulgaris were witnessed against the concentrations of 100 ?g/disc. Promising potential and the future prospects of S. cinereum nanoparticles in pharmaceutical research are the highlights in this paper. PMID:24403664

  11. Optimization for rapid synthesis of silver nanoparticles and its effect on phytopathogenic fungi

    NASA Astrophysics Data System (ADS)

    Krishnaraj, C.; Ramachandran, R.; Mohan, K.; Kalaichelvan, P. T.

    In this present study, silver nanoparticles were synthesized by green chemistry approach using Acalypha indica leaf extract as reducing agents. The reaction medium employed in the synthesis process was optimized to attain better yield, controlled size and stability. Further, the biosynthesized silver nanoparticles were conformed through UV-vis spectrum, XRD and HR-TEM analyses. Different concentration of silver nanoparticles were tested to know the inhibitory effect of fungal plant pathogens namely Alternaria alternata, Sclerotinia sclerotiorum, Macrophomina phaseolina, Rhizoctonia solani, Botrytis cinerea and Curvularia lunata. Interestingly, 15 mg concentration of silver nanoparticles showed excellent inhibitory activity against all the tested pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi.

  12. Oleic acid capped PbS nanoparticles: Synthesis, characterization and tribological properties

    Microsoft Academic Search

    Shuang Chen; Weimin Liu

    2006-01-01

    Oleic acid (OA) capped PbS nanoparticles were chemically synthesized and characterized by means of Fourier transform-infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray electron diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The triboligical properties of the capped PbS nanoparticles as additive in liquid paraffin was investigated using a four-ball machine. The lubricating mechanisms were discussed along with the analyses results

  13. Synthesis and optical properties of silver nanoparticles stabilized by gemini surfactant

    Microsoft Academic Search

    Jian Xu; Xia Han; Honglai Liu; Ying Hu

    2006-01-01

    Silver nanoparticles were prepared by the reduction of silver nitrate using NaBH4 as reducing agent in water-in-oil reverse micelles system, in which gemini surfactant 2-hydroxy-1, 3-bis(octadecyldimethylammonium) propane dibromide (18-3(OH)-18) was used as stabilizer. The results of TEM, AFM and UV–vis absorption spectra show that the silver nanoparticles have a narrow size distribution. The results of UV–vis absorption spectra and XPS

  14. Preparation of Concentrated Stable Fluids Containing Silver Nanoparticles in Nonpolar Organic Solvent

    Microsoft Academic Search

    Fu Xun; Yu Wei; Lin Yusheng; Wang Debao; Shi Huaqiang; Yan Fengyuan

    2005-01-01

    Stable fluids containing silver nanoparticles in kerosene have been prepared by the extraction?reduction method. Silver nitrate was extracted in nonpolar solvent by thio?substituted phosphinic acid extractant Cyanex 302, and then Ag was reduced by solid KBH4. In order to enhance the loading content of silver nanoparticles in the fluids, a tri?block copolymer (PEO)20(PPO)70(PEO)20 was added into the organic phase before

  15. Toxicity effect of silver nanoparticles in brine shrimp Artemia.

    PubMed

    Arulvasu, Chinnasamy; Jennifer, Samou Michael; Prabhu, Durai; Chandhirasekar, Devakumar

    2014-01-01

    The present study revealed the toxic effect of silver nanoparticles (AgNPs) in Artemia nauplii and evaluated the mortality rate, hatching percentage, and genotoxic effect in Artemia nauplii/cysts. The AgNPs were commercially purchased and characterized using field emission scanning electron microscope with energy dispersive X-ray spectroscopy. Nanoparticles were spherical in nature and with size range of 30-40 nm. Artemia cysts were collected from salt pan, processed, and hatched in sea water. Artemia nauplii (II instar) were treated using silver nanoparticles of various nanomolar concentrations and LC50 value (10 nM) and mortality rate (24 and 48 hours) was evaluated. Hatching percentage of decapsulated cysts treated with AgNPs was examined. Aggregation of AgNPs in the gut region of nauplii was studied using phase contrast microscope and apoptotic cells in nauplii stained with acridine orange were observed using fluorescence microscope. DNA damage of single cell of nauplii was determined by comet assay. This study showed that as the concentration of AgNPs increased, the mortality rate, aggregation in gut region, apoptotic cells, and DNA damage increased in nauplii, whereas the percentage of hatching in Artemia cysts decreased. Thus this study revealed that the nanomolar concentrations of AgNPs have toxic effect on both Artemia nauplii and cysts. PMID:24516361

  16. Surface plasmon resonance optical sensor and antibacterial activities of biosynthesized silver nanoparticles.

    PubMed

    Bindhu, M R; Umadevi, M

    2014-01-01

    Silver nanoparticles were prepared using aqueous fruit extract of Ananas comosus as reducing agent. These silver nanoparticles showed surface plasmon peak at 439 nm. They were monodispersed and spherical in shape with an average particle size of 10 nm. The crystallinity of these nanoparticles was evident from clear lattice fringes in the HRTEM images and bright circular spots in the SAED pattern. The antibacterial activities of prepared nanoparticles were found to be size-dependent, the smaller nanoparticles showing more bactericidal effect. Aqueous Zn(2+) and Cu(4+) selectivity and sensitivity study of this green synthesized nanoparticle was performed by optical sensor based surface plasmon resonance (SPR) at room temperature. PMID:24291437

  17. Dispersion and rheology of surfactant-mediated silver nanoparticle suspensions

    NASA Astrophysics Data System (ADS)

    Chen, Chun-Nan; Huang, Chih-Ta; Tseng, Wenjea J.; Wei, Ming-Hsiung

    2010-11-01

    Polycrystalline silver (Ag) nanoparticles were dispersed in solvent mixtures consisting of 2-butoxyethyl acetate (BCA) and diethylene glycol monoethyl ether acetate (CA) in a BCA:CA weight ratio of 5:1. Three commercially available polymeric surfactants were used, and the gravitational sedimentation, agglomerate-size distribution, isothermal adsorption, and rheological behavior of the nanoparticle suspensions were examined. One of the surfactants (hereafter termed 9250) was found effective in stabilizing the Ag nanoparticle suspensions. Both the adsorption isotherm and the Fourier transform infrared spectroscopy revealed the preferential adsorption of the 9250 surfactant molecules on the nanoparticle surface, forming a Langmuir-type monolayer adsorption in the given solvents so that a steric stabilization was rendered. An optimal surfactant concentration of 5 wt.% (in terms of the solids weight) was determined experimentally. In addition, the Ag suspensions with a broad range of solids concentration (? = 1-16 vol.%) showed a shear-thinning flow character over a shear-rate range from 1 to 4000 s-1, revealing that an attractive interparticle interaction was operative. Relative viscosity (?r) of the nanoparticle suspensions deviated from the linearity when ? was greater than ˜10 vol.%; at which, the attractive potential began to dominate the interparticle interactions. This ?r-? dependence was compared with various existing models and the (viscosity) predictive capability of the models was discussed.

  18. Biogenic silver nanoparticles for cancer treatment: an experimental report.

    PubMed

    Jeyaraj, M; Sathishkumar, G; Sivanandhan, G; MubarakAli, D; Rajesh, M; Arun, R; Kapildev, G; Manickavasagam, M; Thajuddin, N; Premkumar, K; Ganapathi, A

    2013-06-01

    A generation of nanoparticles research has discussed recently. It is mandatory to elaborate the applications of biogenic nanoparticles in general and anticancereous property in particular. The present study was aimed to investigate the in vitro cytotoxicity effect of biogenic silver nanoparticles (AgNPs) against human breast cancer (MCF-7) cells towards the development of anticancer agent. Biogenic AgNPs were achieved by employing Sesbania grandiflora leaf extract as a novel reducing agent. It was well characterized by FESEM, EDAX and spectral studies showed spherical shaped nanoparticles in the size of 22 nm in slightly agglomerated form. It was surprising that biogenic AgNPs showed cytotoxic effect against MCF-7 cell lines were confirmed by MTT, AO-EB, Hochest and COMET assays. There was an immediate induction of cellular damage in terms of loss of cell membrane integrity, oxidative stress and apoptosis were found in the cell which treated with AgNPs. This may be a first report on anti-MCF-7 property of biogenic AgNPs in the fourth generation of nanoparticles research. It is necessary to study the formulation and clinical trials to establish the nano drug to treat cancer cells. PMID:23434696

  19. Procedure optimization for green synthesis of silver nanoparticles by aqueous extract of Eucalyptus oleosa.

    PubMed

    Pourmortazavi, Seied Mahdi; Taghdiri, Mehdi; Makari, Vajihe; Rahimi-Nasrabadi, Mehdi

    2014-10-16

    The present study is dealing with the green synthesis of silver nanoparticles using the aqueous extract of Eucalyptus oleosa as a green synthesis procedure without any catalyst, template or surfactant. Colloidal silver nanoparticles were synthesized by reacting aqueous AgNO3 with E. oleosa leaf extract at non-photomediated conditions. The significance of some synthesis conditions such as: silver nitrate concentration, concentration of the plant extract, time of synthesis reaction and temperature of plant extraction procedure on the particle size of synthesized silver particles was investigated and optimized. The participations of the studied factors in controlling the particle size of reduced silver were quantitatively evaluated via analysis of variance (ANOVA). The results of this investigation showed that silver nanoparticles could be synthesized by tuning significant parameters, while performing the synthesis procedure at optimum conditions leads to form silver nanoparticles with 21nm as averaged size. Ultraviolet-visible spectroscopy was used to monitor the development of silver nanoparticles formation. Meanwhile, produced silver nanoparticles were characterized by scanning electron microscopy, energy-dispersive X-ray, and FT-IR techniques. PMID:25456666

  20. Sequential studies of silver released from silver nanoparticles in aqueous media simulating sweat, laundry detergent solutions and surface water.

    PubMed

    Hedberg, Jonas; Skoglund, Sara; Karlsson, Maria-Elisa; Wold, Susanna; Odnevall Wallinder, Inger; Hedberg, Yolanda

    2014-07-01

    From an increased use of silver nanoparticles (Ag NPs) as an antibacterial in consumer products follows a need to assess the environmental interaction and fate of their possible dispersion and release of silver. This study aims to elucidate an exposure scenario of the Ag NPs potentially released from, for example, impregnated clothing by assessing the release of silver and changes in particle properties in sequential contact with synthetic sweat, laundry detergent solutions, and freshwater, simulating a possible transport path through different aquatic media. The release of ionic silver is addressed from a water chemical perspective, compared with important particle and surface characteristics. Released amounts of silver in the sequential exposures were significantly lower, approximately a factor of 2, than the sum of each separate exposure. Particle characteristics such as speciation (both of Ag ionic species and at the Ag NP surface) influenced the release of soluble silver species present on the surface, thereby increasing the total silver release in the separate exposures compared with sequential immersions. The particle stability had no drastic impact on the silver release as most of the Ag NPs were unstable in solution. The silver release was also influenced by a lower pH (increased release of silver), and cotransported zeolites (reduced silver in solution). PMID:24892700

  1. Synthesis of anisotropic silver nanoparticles using novel strain, Bacillus flexus and its biomedical application.

    PubMed

    Priyadarshini, S; Gopinath, V; Meera Priyadharsshini, N; MubarakAli, D; Velusamy, P

    2013-02-01

    Synthesis of metallic nanoparticles has attracted by bacterial based production and alternative to physical and chemical approaches. The present work was focused to nominate a bacterial strain for synthesis of potential silver nanoparticles. The target was achieved by screening of 127 isolates from silver mining wastes. A strain designated S-27 found to be a potential candidate for rapid synthesis of silver nanoparticles among tested microorganisms. It was subjected to molecular characterization by 16S rDNA sequence analysis. It was found that S-27 belonging to Bacillus flexus. Synthesis of silver nanoparticles was achieved by addition of culture supernatants with aqueous silver nitrate solution, immediately it turns to brown colour solution showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles by UV-vis spectroscopy. Various instrumentation techniques, such as AFM, FESEM, XRD and FTIR, were adopted to characterize the synthesized nanoparticles. Anisotropic nanoparticles, such as spherical and triangular shaped nanoparticles, have been synthesized and sizes were found to be 12 and 65 nm, respectively. It was stable in aqueous solution in five months period of storage at room temperature in the dark. Synthesized nanoparticles showed efficacy on antibacterial property against clinically isolated multi-drug resistant (MDR) microorganisms. It is suggested that biogenic synthesis of nanoparticles have wide-application in medicine and physical chemistry and it can produce with eco-friendly, easy downstream processing and rapid scale-up processing. PMID:23018021

  2. Supercritical carbon dioxide-assisted synthesis of silver nano-particles in polyol process

    Microsoft Academic Search

    Yu-Wen Chih; Wen-Tung Cheng

    2007-01-01

    Silver nano-particles have been synthesized by the polyol process with the assistance of supercritical carbon dioxide (SCCO2), with silver nitrate used as the base material, polyvinyl pyrrolidone (PVP) as the stabilizer for the silver clusters, and ethylene glycol as the reducing agent and solvent. Polyvinyl pyrrolidone not only protected nano-size silver particles from aggregation, but it also promoted nucleation. The

  3. Magnetic Silver-Coated Ferrite Nanoparticles and Their Application in Thick Films

    Microsoft Academic Search

    Jianguo Liu; Baling Huang; Xiangyou Li; Ping Li; Xiaoyan Zeng

    2010-01-01

    Magnetic silver-coated ferrite nanoparticles with 39.8% weight gain (relative to ferrite nanopowder coated by a silver layer)\\u000a were synthesized by electroless deposition of silver on ferrite nanopowder. The mechanism of the electroless deposition was\\u000a explored in terms of pretreatment, sensitization, activation, and the reduction of silver–ammonia complexes. Experiments showed\\u000a that the optimal deposition conditions were a temperature of 50°C, pH

  4. Spectroscopic, microscopic and catalytic properties of silver nanoparticles synthesized using Saraca indica flower

    NASA Astrophysics Data System (ADS)

    Vidhu, V. K.; Philip, Daizy

    2014-01-01

    The bioprospective field is dynamic area of research in the recent years. The present article reports a green synthetic route for the production of highly stable, bio-inspired silver nanoparticles using dried Saraca indica flower. The method is facile, cost effective, simple and reproducible. The reduction of silver ions and the formation of silver nanoparticles has been monitored using UV-visible spectroscopy. The TEM, SAED and XRD result reveal that the silver nanoparticles are crystalline in nature. FTIR spectra are used to identify the biomolecules that bind on the surface of silver nanoparticles, which increased the stability of the particles. S. indica flower extract plays its role as an excellent reducing agent of silver ions and the biosynthesized silver nanoparticles are safer to environment. Also the size dependent catalytic activity of silver nanoparticles in the reduction of cationic dye, Methylene blue by NaBH4 is studied by UV-visible spectroscopy. The efficiency of synthesized nanoparticles as an excellent catalyst is proved by the reduction of Methylene blue which is confirmed by the decrease in the absorbance with time and is attributed to electron relay effect.

  5. Phytosynthesis and Characterization of Silver Nanoparticles Using Callus of JATROPHA CURCAS: a Biotechnological Approach

    NASA Astrophysics Data System (ADS)

    Demissie, A. G.; Lele, S. S.

    2013-04-01

    The present study reports a rapid plant-based biosynthesis of silver nanoparticles using callus extract of Jatropha curcas L. The particle size and morphological analyses were carried out using Zetasizer, SEM, TEM. The physicochemical properties were monitored using UV-Vis spectroscopic, IR and DSC. The formation of silver nanoparticle was confirmed by using UV-Vis spectrophotometer and absorbance peaks at 421 nm. The silver nanoparticle was found to be a negatively charged with size ranging from 2 nm to 50 nm. The morphology of the nanoparticle is uniformly spherical and has a dispersion ratio of 0.14. The physicochemical study using DSC indicated significant thermal stability and crystalline nature of the nanoparticle. This intracellular biosynthesis of silver nanoparticles is simple, cheap and eco-friendly than other mechanical and chemical approaches.

  6. Photoemission Electron Microscopy of a Plasmonic Silver Nanoparticle Trimer

    SciTech Connect

    Peppernick, Samuel J.; Joly, Alan G.; Beck, Kenneth M.; Hess, Wayne P.; Wang, Jinyong; Wang, Yi-Chung; Wei, Wei

    2013-07-01

    We present a combined experimental and theoretical study to investigate the spatial distribution of photoelectrons emitted from core-shell silver (Ag) nanoparticles. We use two-photon photoemission microscopy (2P-PEEM) to spatially resolve electron emission from a trimeric core-shell aggregate of triangular symmetry. Finite difference time domain (FDTD) simulations are performed to model the intensity distributions of the electromagnetic near-fields resulting from femtosecond (fs) laser excitation of localized surface plasmon oscillations in the triangular core-shell structure. We demonstrate that the predicted FDTD near-field intensity distribution reproduces the 2P-PEEM photoemission pattern.

  7. Highly anisotropic effective dielectric functions of silver nanoparticle arrays.

    PubMed

    Oates, Thomas W H; Ranjan, Mukesh; Facsko, Stefan; Arwin, Hans

    2011-01-31

    Variable-angle and Mueller matrix spectroscopic ellipsometry are used to determine the effective dielectric tensors of random and aligned silver nanoparticles and nanorods thin films. Randomly arranged particles are uniaxially anisotropic while aligned particles are biaxially anisotropic, with the anisotropy predominantly at the plasmonic resonances. The strong resonances in nanorod arrays result in the real part of the effective in-plane permittivities being opposite in sign over a significant range in the visible, suggesting the potential to design materials that display tunable negative-refraction. A structural tilt in the particle arrays results in monoclinic dielectric properties. PMID:21369018

  8. Reversible strong coupling in silver nanoparticle arrays using photochromic molecules.

    PubMed

    Baudrion, Anne-Laure; Perron, Antoine; Veltri, Alessandro; Bouhelier, Alexandre; Adam, Pierre-Michel; Bachelot, Renaud

    2013-01-01

    In this Letter, we demonstrate a reversible strong coupling regime between a dipolar surface plasmon resonance and a molecular excited state. This reversible state is experimentally observed on silver nanoparticle arrays embedded in a polymer film containing photochromic molecules. Extinction measurements reveal a clear Rabi splitting of 294 meV, corresponding to ~13% of the molecular transition energy. We derived an analytical model to confirm our observations, and we emphasize the importance of spectrally matching the polymer absorption with the plasmonic resonance to observe coupled states. Finally, the reversibility of this coupling is illustrated by cycling the photochromic molecules between their two isomeric forms. PMID:23249360

  9. Preparation and optical properties of colloidal silver nanoparticles at a high Ag + concentration

    Microsoft Academic Search

    M. Habib Ullah; Kim Il; Chang-Sik Ha

    2006-01-01

    We have prepared colloidal silver nanoparticles by reducing a high molar concentration of AgNO3 (up to 0.735 M) with glycerol in the presence of m-phenylenediamine. These silver nanoparticles had anisotropic shapes, including truncated rectangles, truncated triangles, and spheroid-type particles. The UV–Vis spectra of these nanoparticle systems display two distinct plasmon modes and a shoulder that correspond to the in-plane dipole,

  10. Silver nanoparticle aided self-healing of polyelectrolyte multilayers.

    PubMed

    Huang, Xiayun; Bolen, Matthew J; Zacharia, Nicole S

    2014-06-14

    Self-healing is the ability of a material to repair mechanical damage. The lifetime of a coating or film might be lengthened with this capacity. Water enabled self-healing of polyelectrolyte multilayers has been reported, using systems that grow via the interdiffusion of polyelectrolyte chains. Due to high mobility of the polyelectrolyte chains within the assembly, it is possible for lateral diffusion to heal over scratches. The influence of metal ions and nanoparticles on this property has, however, not been previously studied. Here we demonstrate that the incorporation of silver nanoparticles reduced in situ within the branched poly(ethyleneimine)-poly(acrylic acid) polyelectrolyte multilayer structure speeds the ability of the multilayer assembly to self-heal. This enhancement of property seems to not be due to changes in mechanical properties but rather in enhanced affinity to water and plasticization that enables the film to better swell. PMID:24728290

  11. Antifungal activity of silver nanoparticles obtained by green synthesis.

    PubMed

    Mallmann, Eduardo José J; Cunha, Francisco Afrânio; Castro, Bruno N M F; Maciel, Auberson Martins; Menezes, Everardo Albuquerque; Fechine, Pierre Basílio Almeida

    2015-01-01

    Silver nanoparticles (AgNPs) are metal structures at the nanoscale. AgNPs have exhibited antimicrobial activities against fungi and bacteria; however synthesis of AgNPs can generate toxic waste during the reaction process. Accordingly, new routes using non-toxic compounds have been researched. The proposal of the present study was to synthesize AgNPs using ribose as a reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer. The antifungal activity of these particles against C. albicans and C. tropicalis was also evaluated. Stable nanoparticles 12.5 ± 4.9 nm (mean ± SD) in size were obtained, which showed high activity against Candida spp. and could represent an alternative for fungal infection treatment. PMID:25923897

  12. The Speciation of Silver Nanoparticles in Antimicrobial Fabric Before and After Exposure to a Hypochlorite\\/Detergent Solution

    Microsoft Academic Search

    Christopher A. Impellitteri; Thabet M. Tolaymat; Kirk G. Scheckel

    2009-01-01

    Because of their antibacterial properties, silver nanoparticles are often used in consumer products. To assess environmental and\\/or human health risks from these nanoparticles, there is a need to identify the chemical transformations that silver nanoparticles undergo in different environments. Thus an antimicrobial sock material containing Ag nanoparticles was examined by X-ray absorption spectroscopy to identify the speciation of Ag. The

  13. Synthesis of colloidal Janus nanoparticles by asymmetric capping of mesoporous silica with phenylsilsesquioxane.

    PubMed

    Ujiie, Hiroto; Shimojima, Atsushi; Kuroda, Kazuyuki

    2015-02-21

    Colloidal mesoporous silica nanoparticles asymmetrically capped with non-porous phenylsilsesquioxane have been prepared by adding phenyltriethoxysilane to an aqueous dispersion of mesostructured silica-surfactant composite nanoparticles. The integration of colloidal stability, mesoporosity and the Janus structure is quite promising for materials design applicable in various fields, including catalysis, biomedicine and coatings. PMID:25605540

  14. Effects of silver nitrate and silver nanoparticles on a planktonic community: general trends after short-term exposure.

    PubMed

    Boenigk, Jens; Beisser, Daniela; Zimmermann, Sonja; Bock, Christina; Jakobi, Jurij; Grabner, Daniel; Gro?mann, Lars; Rahmann, Sven; Barcikowski, Stephan; Sures, Bernd

    2014-01-01

    Among metal pollutants silver ions are one of the most toxic forms, and have thus been assigned to the highest toxicity class. Its toxicity to a wide range of microorganisms combined with its low toxicity to humans lead to the development of a wealth of silver-based products in many bactericidal applications accounting to more than 1000 nano-technology-based consumer products. Accordingly, silver is a widely distributed metal in the environment originating from its different forms of application as metal, salt and nanoparticle. A realistic assessment of silver nanoparticle toxicity in natural waters is, however, problematic and needs to be linked to experimental approaches. Here we apply metatranscriptome sequencing allowing for elucidating reactions of whole communities present in a water sample to stressors. We compared the toxicity of ionic silver and ligand-free silver nanoparticles by short term exposure on a natural community of aquatic microorganisms. We analyzed the effects of the treatments on metabolic pathways and species composition on the eukaryote metatranscriptome level in order to describe immediate molecular responses of organisms using a community approach. We found significant differences between the samples treated with 5 µg/L AgNO3 compared to the controls, but no significant differences in the samples treated with AgNP compared to the control samples. Statistical analysis yielded 126 genes (KO-IDs) with significant differential expression with a false discovery rate (FDR) <0.05 between the control (KO) and AgNO3 (NO3) groups. A KEGG pathway enrichment analysis showed significant results with a FDR below 0.05 for pathways related to photosynthesis. Our study therefore supports the view that ionic silver rather than silver nanoparticles are responsible for silver toxicity. Nevertheless, our results highlight the strength of metatranscriptome approaches for assessing metal toxicity on aquatic communities. PMID:24755991

  15. Effects of Silver Nitrate and Silver Nanoparticles on a Planktonic Community: General Trends after Short-Term Exposure

    PubMed Central

    Boenigk, Jens; Beisser, Daniela; Zimmermann, Sonja; Bock, Christina; Jakobi, Jurij; Grabner, Daniel; Großmann, Lars; Rahmann, Sven; Barcikowski, Stephan; Sures, Bernd

    2014-01-01

    Among metal pollutants silver ions are one of the most toxic forms, and have thus been assigned to the highest toxicity class. Its toxicity to a wide range of microorganisms combined with its low toxicity to humans lead to the development of a wealth of silver-based products in many bactericidal applications accounting to more than 1000 nano-technology-based consumer products. Accordingly, silver is a widely distributed metal in the environment originating from its different forms of application as metal, salt and nanoparticle. A realistic assessment of silver nanoparticle toxicity in natural waters is, however, problematic and needs to be linked to experimental approaches. Here we apply metatranscriptome sequencing allowing for elucidating reactions of whole communities present in a water sample to stressors. We compared the toxicity of ionic silver and ligand-free silver nanoparticles by short term exposure on a natural community of aquatic microorganisms. We analyzed the effects of the treatments on metabolic pathways and species composition on the eukaryote metatranscriptome level in order to describe immediate molecular responses of organisms using a community approach. We found significant differences between the samples treated with 5 µg/L AgNO3 compared to the controls, but no significant differences in the samples treated with AgNP compared to the control samples. Statistical analysis yielded 126 genes (KO-IDs) with significant differential expression with a false discovery rate (FDR) <0.05 between the control (KO) and AgNO3 (NO3) groups. A KEGG pathway enrichment analysis showed significant results with a FDR below 0.05 for pathways related to photosynthesis. Our study therefore supports the view that ionic silver rather than silver nanoparticles are responsible for silver toxicity. Nevertheless, our results highlight the strength of metatranscriptome approaches for assessing metal toxicity on aquatic communities. PMID:24755991

  16. Improving of enzyme immunoassay for detection and quantification of the target molecules using silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Syrvatka, Vasyl J.; Slyvchuk, Yurij I.; Rozgoni, Ivan I.; Gevkan, Ivan I.; Overchuk, Marta O.

    2014-02-01

    Modern routine enzyme immunoassays for detection and quantification of biomolecules have several disadvantages such as high cost, insufficient sensitivity, complexity and long-term execution. The surface plasmon resonance of silver nanoparticles gives reasons of creating new in the basis of simple, highly sensitive and low cost colorimetric assays that can be applied to the detection of small molecules, DNA, proteins and pollutants. The main aim of the study was the improving of enzyme immunoassay for detection and quantification of the target molecules using silver nanoparticles. For this purpose we developed method for synthesis of silver nanoparticles with hyaluronic acid and studied possibility of use these nanoparticles in direct determination of target molecules concentration (in particular proteins) and for improving of enzyme immunoassay. As model we used conventional enzyme immunoassays for determination of progesterone and estradiol concentration. We obtained the possibility to produce silver nanoparticles with hyaluronan homogeneous in size between 10 and 12 nm, soluble and stable in water during long term of storage using modified procedure of silver nanoparticles synthesis. New method allows to obtain silver nanoparticles with strong optical properties at the higher concentrations - 60-90 ?g/ml with the peak of absorbance at the wavelength 400 nm. Therefore surface plasmon resonance of silver nanoparticles with hyaluronan and ultraviolet-visible spectroscopy provide an opportunity for rapid determination of target molecules concentration (especial protein). We used silver nanoparticles as enzyme carriers and signal enhancers. Our preliminary data show that silver nanoparticles increased absorbance of samples that allows improving upper limit of determination of estradiol and progesterone concentration.

  17. Biological activities of green silver nanoparticles synthesized with Acorous calamus rhizome extract.

    PubMed

    Nakkala, Jayachandra Reddy; Mata, Rani; Gupta, Arvind Kumar; Sadras, Sudha Rani

    2014-10-01

    Nanomedicine utilize biocompatible nanomaterials for diagnostic and therapeutic purposes. This study reports the synthesis of silver nanoparticles using aqueous rhizome extract of Acorus calamus (ACRE) and evaluation of antioxidant, antibacterial as well as anticancer effects of synthesized A. calamus silver nanoparticles (ACAgNPs). The formation of ACAgNPs was confirmed by UV-visible spectroscopy and their average size was found to be 31.83 nm by DLS particle size analyzer. Scanning electron micrograph (SEM) revealed spherical shape of ACAgNPs and energy dispersive spectroscopy (EDX) data showed the presence of metallic silver. Fourier transform infrared spectroscopy (FTIR) analysis indicated the presence of phenol/alcohol, aromatic amine and carbonyl groups in ACRE that were involved in reduction and capping of nanoparticles. ACRE and ACAgNPs exhibited substantial free radical quenching ability in various in vitro antioxidant assays performed in this study. ACAgNPs also displayed appreciable antibacterial activity against three different pathogenic bacteria and the growth kinetic study with Escherichia coli designated the inhibition of bacterial growth at the log phase. The cytotoxic effect of ACAgNPs was assessed by MTT assay in HeLa and A549 cells. The IC50 value of ACAgNPs respectively after 24 and 48 h was found to be 92.48 and 69.44 ?g/ml in HeLa cells and in A549 cells it was 53.2 and 32.1 ?g/ml. Apoptotic cell death in ACAgNPs treated cells was indicated by acridine orange/ethidium bromide (AO/EB) and annexinV-Cy3 staining techniques. Staining with propidium iodide (PI) and 4', 6-diamidino-2-phenylindole, dihydrochloride (DAPI) also confirmed nuclear changes such as condensation and fragmentation. Further, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay showed distribution of ACAgNPs treated cells in the late apoptotic stage. These findings emphasize that such biocompatible green nanoparticles with multifaceted biological activities may find their applications in the field of nanomedicine. PMID:25147142

  18. Degradable polyphosphoester-based silver-loaded nanoparticles as therapeutics for bacterial lung infections

    NASA Astrophysics Data System (ADS)

    Zhang, Fuwu; Smolen, Justin A.; Zhang, Shiyi; Li, Richen; Shah, Parth N.; Cho, Sangho; Wang, Hai; Raymond, Jeffery E.; Cannon, Carolyn L.; Wooley, Karen L.

    2015-01-01

    In this study, a new type of degradable polyphosphoester-based polymeric nanoparticle, capable of carrying silver cations via interactions with alkyne groups, has been developed as a potentially effective and safe treatment for lung infections. It was found that up to 15% (w/w) silver loading into the nanoparticles could be achieved, consuming most of the pendant alkyne groups along the backbone, as revealed by Raman spectroscopy. The well-defined Ag-loaded nanoparticles released silver in a controlled and sustained manner over 5 days, and displayed enhanced in vitro antibacterial activities against cystic fibrosis-associated pathogens and decreased cytotoxicity to human bronchial epithelial cells, in comparison to silver acetate.In this study, a new type of degradable polyphosphoester-based polymeric nanoparticle, capable of carrying silver cations via interactions with alkyne groups, has been developed as a potentially effective and safe treatment for lung infections. It was found that up to 15% (w/w) silver loading into the nanoparticles could be achieved, consuming most of the pendant alkyne groups along the backbone, as revealed by Raman spectroscopy. The well-defined Ag-loaded nanoparticles released silver in a controlled and sustained manner over 5 days, and displayed enhanced in vitro antibacterial activities against cystic fibrosis-associated pathogens and decreased cytotoxicity to human bronchial epithelial cells, in comparison to silver acetate. Electronic supplementary information (ESI) available: Materials, experimental details, and characterization. See DOI: 10.1039/c4nr07103d

  19. Biosynthesis and characterization of silver nanoparticles using panchakavya, an Indian traditional farming formulating agent

    PubMed Central

    Govarthanan, Muthusamy; Selvankumar, Thangasamy; Manoharan, Koildhasan; Rathika, Rajiniganth; Shanthi, Kuppusamy; Lee, Kui-Jae; Cho, Min; Kamala-Kannan, Seralathan; Oh, Byung-Taek

    2014-01-01

    Synthesis of silver nanoparticles (AgNPs) with biological properties is of vast significance in the development of scientifically valuable products. In the present study, we describe simple, unprecedented, nontoxic, eco-friendly, green synthesis of AgNPs using an Indian traditional farming formulating agent, panchakavya. Silver nitrate (1 mM) solution was mixed with panchakavya filtrate for the synthesis of AgNPs. The nanometallic dispersion was characterized by surface plasmon absorbance measuring 430 nm. Transmission electron microscopy showed the morphology and size of the AgNPs. Scanning electron microscopy–energy-dispersive spectroscopy and X-ray diffraction analysis confirmed the presence of AgNPs. Fourier transform infrared spectroscopy analysis revealed that proteins in the panchakavya were involved in the reduction and capping of AgNPs. In addition, we studied the antibacterial activity of synthesized AgNPs. The synthesized AgNPs (1–4 mM) extensively reduced the growth rate of antibiotic resistant bacteria such as Aeromonas sp., Acinetobacter sp., and Citrobacter sp., according to the increasing concentration of AgNPs. PMID:24741307

  20. Influence of ammonia on silver nanoparticle dissolution and toxicity to Nitrosomonas europaea.

    PubMed

    Kostigen Mumper, Cameron; Ostermeyer, Ann-Kathrin; Semprini, Lewis; Radniecki, Tyler S

    2013-11-01

    Nitrosomonas europaea, a model ammonia oxidizing bacterium, was sensitive to both ionic silver (Ag(+)) and 20 nm citrate capped silver nanoparticles (AgNPs). AgNP toxicity has been previously shown to be primarily due to the dissolution of Ag(+). The rate of AgNP dissolution dramatically increased in test medium containing ammonium sulfate ((NH4)2SO4) and HEPES buffer compared to test medium containing either deionized water or HEPES buffer alone. The AgNP dissolution rates accelerated with increases in ammonia (NH3) concentrations either through increases in pH or through higher (NH4)2SO4 concentrations. Ammonia likely participated in the oxidation of the AgNP to form [Formula: see text] in solution leading to the observed increase in AgNP dissolution rates. AgNP toxicity was enhanced as NH3 concentrations increased. However, Ag(+) toxicity was constant at all NH3 concentrations tested. Therefore, it can be concluded that the increased AgNP toxicity was due to increased Ag(+) release and not due to a synergistic effect between NH3 and Ag(+). The results of this study may provide insights in the fate and toxicity of AgNPs in high NH3 environments including wastewater treatment plants, eutrophic waterways and alkaline environments. PMID:24120011

  1. Interactive effects of silver nanoparticles and phosphorus on phytoplankton growth in natural waters.

    PubMed

    Das, Pranab; Metcalfe, Chris D; Xenopoulos, Marguerite A

    2014-04-15

    Increasing amounts of silver nanoparticles (AgNPs) are expected to enter the aquatic ecosystems where their effects on natural phytoplankton communities are poorly understood. We investigated the effects of AgNPs and its interactions with phosphorus (P) supply on the growth kinetics and stoichiometry of natural phytoplankton. Lake water was dosed with AgNPs (carboxy-functionalized capping agent; ?10-nm particle size; ?20% Ag w/w) at four different concentrations and five P concentrations and incubated in situ for 3 days. A treatment with ionic silver (AgNO3) was used as a positive control. We found that growth rates, calculated from changes in seston carbon and chlorophyll, responded significantly and interactively (p < 0.0001) to both AgNPs and P. AgNPs reduced the maximum phytoplankton growth rates by 11-85%. In the positive control, no or very little growth was observed. Inhibition of growth rates after exposure to Ag might be related to the reduction in chlorophyll and the inhibition of C and N acquisition rather than P uptake mechanisms. AgNPs, P supply and their interactions also significantly (p < 0.0001) reduced sestonic C:P and N:P ratios and increased C:N, C:Chl and cell-bound Ag stoichiometry. Our results indicate that fate and toxicity of AgNP will vary with phosphorus pollution level in aquatic ecosystems. PMID:24628458

  2. Memecylon edule leaf extract mediated green synthesis of silver and gold nanoparticles

    PubMed Central

    Elavazhagan, Tamizhamudu; Arunachalam, Kantha D

    2011-01-01

    We used an aqueous leaf extract of Memecylon edule (Melastomataceae) to synthesize silver and gold nanoparticles. To our knowledge, this is the first report where M. edule leaf broth was found to be a suitable plant source for the green synthesis of silver and gold nanoparticles. On treatment of aqueous solutions of silver nitrate and chloroauric acid with M. edule leaf extract, stable silver and gold nanoparticles were rapidly formed. The gold nanoparticles were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX) and Fourier transform infra-red spectroscopy (FTIR). The kinetics of reduction of aqueous silver and gold ions during reaction with the M. edule leaf broth were easily analyzed by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to M. edule leaf broth, were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20–50 nm. TEM analysis of gold nanoparticles showed formation of triangular, circular, and hexagonal shapes in the size range 10–45 nm. The resulting silver nanoparticles were predominantly square with uniform size range 50–90 nm. EDAX results confirmed the presence of triangular nanoparticles in the adsorption peak of 2.30 keV. Further FTIR analysis was also done to identify the functional groups in silver and gold nanoparticles. The characterized nanoparticles of M. edule have potential for various medical and industrial applications. Saponin presence in aqueous extract of M. edule is responsible for the mass production of silver and gold nanoparticles. PMID:21753878

  3. A Novel Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles

    PubMed Central

    El-Sheikh, M. A.

    2014-01-01

    The water soluble photoinitiator (PI) 4-(trimethyl ammonium methyl) benzophenone chloride is used for the first time in the synthesis of silver nanoparticles (AgNPs). A new green synthesis method involves using PI/UV system, carboxymethyl starch (CMS), silver nitrate, and water. A mechanism of the reduction of silver ions to AgNPs by PI/UV system as well as by the newly born aldehydic groups was proposed. The synthesis process was assessed by UV-vis spectra and TEM of AgNPs colloidal solution. The highest absorbance was obtained using CMS, PI and AgNO3 concentrations of 10?g/L, 1?g/L, and 1?g/L, respectively; 40°C; 60?min; pH 7; and a material?:?liquor ratio 1?:?20. AgNPs so-obtained were stable in aqueous solution over a period of three weeks at room temperature (~25°C) and have round shape morphology. The sizes of synthesized AgNPs were in the range of 1–21?nm and the highest counts % of these particles were for particles of 6–10 and 1–3?nm, respectively. PMID:24672325

  4. Silver nanoparticles impair Peste des petits ruminants virus replication.

    PubMed

    Khandelwal, Nitin; Kaur, Gurpreet; Chaubey, Kundan Kumar; Singh, Pushpendra; Sharma, Shalini; Tiwari, Archana; Singh, Shoor Vir; Kumar, Naveen

    2014-09-22

    In the present study, we evaluated the antiviral efficacy of the silver nanoparticles (SNPs) against Peste des petits ruminants virus (PPRV), a prototype Morbillivirus. The leaf extract of the Argemone maxicana was used as a reducing agent for biological synthesis of the SNPs from silver nitrate. The SNPs were characterized using UV-vis absorption spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM analysis revealed particle size of 5-30 nm and the XRD analysis revealed their characteristic silver structure. The treatment of Vero cells with the SNPs at a noncytotoxic concentration significantly inhibited PPRV replication in vitro. The time-course and virus step-specific assays showed that the SNPs impair PPRV replication at the level of virus entry. The TEM analysis showed that the SNPs interact with the virion surface as well with the virion core. However, this interaction has no direct virucidal effect, instead exerts a blocking effect on viral entry into the target cells. This is the first documented evidence indicating that the SNPs are capable of inhibiting a Morbillivirus replication in vitro. PMID:24979044

  5. Sulfidation of silver nanoparticles: natural antidote to their toxicity.

    PubMed

    Levard, Clement; Hotze, Ernest M; Colman, Benjamin P; Dale, Amy L; Truong, Lisa; Yang, X Y; Bone, Audrey J; Brown, Gordon E; Tanguay, Robert L; Di Giulio, Richard T; Bernhardt, Emily S; Meyer, Joel N; Wiesner, Mark R; Lowry, Gregory V

    2013-12-01

    Nanomaterials are highly dynamic in biological and environmental media. A critical need for advancing environmental health and safety research for nanomaterials is to identify physical and chemical transformations that affect the nanomaterial properties and their toxicity. Silver nanoparticles, one of the most toxic and well-studied nanomaterials, readily react with sulfide to form Ag(0)/Ag2S core-shell particles. Here, we show that sulfidation decreased silver nanoparticle toxicity to four diverse types of aquatic and terrestrial eukaryotic organisms (Danio rerio (zebrafish), Fundulus heteroclitus (killifish), Caenorhabditis elegans (nematode worm), and the aquatic plant Lemna minuta (least duckweed)). Toxicity reduction, which was dramatic in killifish and duckweed even for low extents of sulfidation (about 2 mol % S), is primarily associated with a decrease in Ag(+) concentration after sulfidation due to the lower solubility of Ag2S relative to elemental Ag (Ag(0)). These results suggest that even partial sulfidation of AgNP will decrease the toxicity of AgNPs relative to their pristine counterparts. We also show that, for a given organism, the presence of chloride in the exposure media strongly affects the toxicity results by affecting Ag speciation. These results highlight the need to consider environmental transformations of NPs in assessing their toxicity to accurately portray their potential environmental risks. PMID:24180218

  6. Antibacterial activity of silver nanoparticles: sensitivity of different Salmonella serovars

    PubMed Central

    Losasso, Carmen; Belluco, Simone; Cibin, Veronica; Zavagnin, Paola; Mi?eti?, Ivan; Gallocchio, Federica; Zanella, Michela; Bregoli, Lisa; Biancotto, Giancarlo; Ricci, Antonia

    2014-01-01

    Salmonella spp. is one of the main causes of foodborne illnesses in humans worldwide. Consequently, great interest exists in reducing its impact on human health by lowering its prevalence in the food chain. Antimicrobial formulations in the form of nanoparticles exert bactericidal action due to their enhanced reactivity resultant from their high surface/volume ratio. Silver nanoparticles (AgNPs) are known to be highly toxic to Gram-negative and Gram-positive microorganisms, including multidrug resistant bacteria. However, few data concerning their success against different Salmonella serovars are available. Aims of the present study were to test the antimicrobial effectiveness of AgNPs, against Salmonella Enteritidis, Hadar, and Senftenberg, and to investigate the causes of their different survival abilities from a molecular point of view. Results showed an immediate, time-limited and serovar-dependent reduction of bacterial viability. In the case of S. Senftenberg, the reduction in numbers was observed for up to 4 h of incubation in the presence of 200 mg/l of AgNPs; on the contrary, S. Enteritidis and S. Hadar resulted to be inhibited for up to 48 h. Reverse transcription and polymerase chain reaction experiments demonstrated the constitutive expression of the plasmidic silver resistance determinant (SilB) by S. Senftenberg, thus suggesting the importance of a cautious use of AgNPs. PMID:24904542

  7. The segregation of silver nanoparticles in low-cost ceramic water filters

    SciTech Connect

    Larimer, Curtis; Ostrowski, Nicole [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, 15261 (United States); Speakman, Jacquelyn [Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA, 15261 (United States); Nettleship, Ian, E-mail: nettles@pitt.edu [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA, 15261 (United States)

    2010-04-15

    As an impregnated constituent in low-cost ceramic water filters, silver nanoparticles have a demonstrated antibacterial effect. The bactericidal mechanism is believed to be based on direct contact between silver and the cell wall of a contaminant organism. In this study microstructural analysis was used to examine the effect of the processing method on the distribution of silver nanoparticles in the filter material. Silver nanofluid was impregnated into fired clay ceramic samples by a low-cost soak-and-dry method. Analyses of filter samples by scanning electron microscopy, energy dispersive spectroscopy, and digital optical topological mapping showed that silver was concentrated in near surface pores, a condition that is not optimal for highest probability of silver contact. A simple experiment showed that segregation of silver occurs during the drying phase of impregnation. Drying curves showed that 90% of contained liquid evaporates from the external surface.

  8. Bacterial flagella as biotemplate for the synthesis of silver nanoparticle impregnated bionanomaterial

    NASA Astrophysics Data System (ADS)

    Gopinathan, Priya; Ashok, Anuradha M.; Selvakumar, R.

    2013-07-01

    The present study was carried out to synthesize one dimensional silver nanoparticle impregnated flagellar bionanomaterial. Flagella was isolated from Salmonella typhimurium and depolymerised into flagellin monomers. The flagellin monomers were repolymerised again into flagella using suitable technique. The molecular weight of native (NF) and polymerized flagella (PF) was determined using polyacrylamide gel electrophoresis. The NF and PF were used as a template, over which silver nanoparticles were impregnated using in situ chemical reduction process. The synthesized flagellar-silver nanoparticle bionanomaterials were characterized using UV-vis, FT-IR Raman and XRD spectroscopy, and High resolution transmission electron microscopy (HR-TEM). The characterization studies confirmed the attachment of silver nanoparticles over flagella and repolymerised flagella. The size of the silver nanoparticles on the flagella and repolymerised flagella varied and was in the range of 3-11 nm. I-V characteristics of the bionanomaterials were analyzed using Kethley meter which indicated the increase of conductivity after impregnation of silver nanoparticles. The results indicated that flagellar-silver nanoparticle bionanomaterials can be used as a potential one dimensional bionanomaterials for various applications.

  9. Fabrication Of Biogenic Silver Nanoparticles Using Agricultural Crop Plant Leaf Extracts

    Microsoft Academic Search

    P. Rajani; K. Srisindhura; T. N. V. K. V. Prasad; O. M. Hussain; P. Sudhakar; P. Latha; M. Balakrishna; V. Kambala; K. Raja Reddy

    2010-01-01

    Nanoparticles are being viewed as fundamental building blocks of nanotechnology. Biosynthesis of nanoparticles by plant extracts is currently under exploitation. Use of agricultural crop plant extracts for synthesis of metal nanoparticles would add a new dimension to the agricultural sector in the utilization of crop waste. Silver has long been recognized as having an inhibitory effect towards many bacterial strains

  10. SINGLE SILVER NANOPARTICLES AS REAL-TIME OPTICAL SENSORS WITH ZEPTOMOLE SENSITIVITY

    E-print Network

    Shull, Kenneth R.

    SINGLE SILVER NANOPARTICLES AS REAL-TIME OPTICAL SENSORS WITH ZEPTOMOLE SENSITIVITY Adam D. Mc-hexadecanethiol (HDT) molecules (~100 zeptomole) on single Ag nanoparticles resulted in a localized surface. Additionally, the kinetics of the single nanoparticle response was shown to be comparable to other real

  11. Green synthesis of gold and silver nanoparticles using Hibiscus rosa sinensis

    Microsoft Academic Search

    Daizy Philip

    2010-01-01

    Biological synthesis of gold and silver nanoparticles of various shapes using the leaf extract of Hibiscus rosa sinensis is reported. This is a simple, cost-effective, stable for long time and reproducible aqueous room temperature synthesis method to obtain a self-assembly of Au and Ag nanoparticles. The size and shape of Au nanoparticles are modulated by varying the ratio of metal

  12. Human skin penetration of silver nanoparticles through intact and damaged skin

    Microsoft Academic Search

    Francesca Filon Larese; Flavia D’Agostin; Matteo Crosera; Gianpiero Adami; Nadia Renzi; Massimo Bovenzi; Giovanni Maina

    2009-01-01

    There is a growing interest on nanoparticle safety for topical use. The benefits of nanoparticles have been shown in several scientific fields, but little is known about their potential to penetrate the skin. This study aims at evaluating in vitro skin penetration of silver nanoparticles. Experiments were performed using the Franz diffusion cell method with intact and damaged human skin.

  13. Silver nanoparticles embedded in zeolite membranes: release of silver ions and mechanism of antibacterial action

    PubMed Central

    Nagy, Amber; Harrison, Alistair; Sabbani, Supriya; Munson, Robert S; Dutta, Prabir K; Waldman, W James

    2011-01-01

    Background The focus of this study is on the antibacterial properties of silver nanoparticles embedded within a zeolite membrane (AgNP-ZM). Methods and Results These membranes were effective in killing Escherichia coli and were bacteriostatic against methicillin-resistant Staphylococcus aureus. E. coli suspended in Luria Bertani (LB) broth and isolated from physical contact with the membrane were also killed. Elemental analysis indicated slow release of Ag+ from the AgNP-ZM into the LB broth. The E. coli killing efficiency of AgNP-ZM was found to decrease with repeated use, and this was correlated with decreased release of silver ions with each use of the support. Gene expression microarrays revealed upregulation of several antioxidant genes as well as genes coding for metal transport, metal reduction, and ATPase pumps in response to silver ions released from AgNP-ZM. Gene expression of iron transporters was reduced, and increased expression of ferrochelatase was observed. In addition, upregulation of multiple antibiotic resistance genes was demonstrated. The expression levels of multicopper oxidase, glutaredoxin, and thioredoxin decreased with each support use, reflecting the lower amounts of Ag+ released from the membrane. The antibacterial mechanism of AgNP-ZM is proposed to be related to the exhaustion of antioxidant capacity. Conclusion These results indicate that AgNP-ZM provide a novel matrix for gradual release of Ag+. PMID:21931480

  14. Bacterial inactivation using silver-coated magnetic nanoparticles as functional antimicrobial agents

    PubMed Central

    Wang, Lingyan; Luo, Jin; Shan, Shiyao; Crew, Elizabeth; Yin, Jun; Zhong, Chuan-Jian; Wallek, Brandi; Wong, Season

    2011-01-01

    The ability for silver nanoparticles to function as an antibacterial agent while being separable from the target fluids is important for bacterial inactivation in biological fluids. This report describes the analysis of the antimicrobial activities of silver-coated magnetic nanoparticles synthesized by wet chemical methods. The bacterial inactivation of several types of bacteria was analyzed, including Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (Pseudomonas aeruginosa, Enterobacter cloacae, and Escherichia coli). The results have demonstrated the viability of the silver-coated magnetic nanoparticles for achieving effective bacterial inactivation efficiency comparable to and better than silver nanoparticles conventionally used. The bacteria inactivation efficiency of our MZF@Ag nanoparticles were also determined for blood platelets samples, demonstrating the potential of utilization in inactivating bacterial growth in platelets prior to transfusion to ensure blood product safety, which also has important implications for enabling the capability of effective separation, delivery and targeting of the antibacterial agents. PMID:21999710

  15. Strategy for the syntheses of isolated fine silver nanoparticles and polypyrrole\\/silver nanocomposites on gold substrates

    Microsoft Academic Search

    Yu-Chuan Liu; Hsun-Tsing Lee; Shung-Jim Yang

    2006-01-01

    In this work, isolated fine silver nanoparticles and polypyrrole\\/silver nanocomposites with diameters of about 10nm on gold substrates were first prepared by electrochemical methods. First, an Ag substrate was cycled in a deoxygenated aqueous solution containing 0.1M HCl from ?0.30 to +0.30V versus Ag\\/AgCl at 5mV\\/s with 30 scans. Subsequently the Ag working electrode was immediately replaced by an Au

  16. Spray-coated nanoscale conductive patterns based on in situ sintered silver nanoparticle inks

    PubMed Central

    2014-01-01

    Nanoscale patterns with high conductivity based on silver nanoparticle inks were fabricated using spray coating method. Through optimizing the solution content and spray operation, accurate nanoscale patterns consisting of silver nanoparticles with a square resistance lower than 1 ? /cm2 were obtained. By incorporating in situ sintering to substitute the general post sintering process, the time consumption could be significantly reduced to one sixth, qualifying it for large-scale and cost-effective fabrication of printed electronics. To testify the application of spray-coated silver nanoparticle inks, an inverted polymer solar cell was also fabricated, which exhibited a power conversion efficiency of 2.76%. PMID:24666992

  17. Mechanistic aspects of biosynthesis of silver nanoparticles by several Fusarium oxysporum strains

    PubMed Central

    Durán, Nelson; Marcato, Priscyla D; Alves, Oswaldo L; De Souza, Gabriel IH; Esposito, Elisa

    2005-01-01

    Extracellular production of metal nanoparticles by several strains of the fungus Fusarium oxysporum was carried out. It was found that aqueous silver ions when exposed to several Fusarium oxysporum strains are reduced in solution, thereby leading to the formation of silver hydrosol. The silver nanoparticles were in the range of 20–50 nm in dimensions. The reduction of the metal ions occurs by a nitrate-dependent reductase and a shuttle quinone extracellular process. The potentialities of this nanotechnological design based in fugal biosynthesis of nanoparticles for several technical applications are important, including their high potential as antibacterial material. PMID:16014167

  18. Biosynthesis of Silver Nanoparticles from Desmodium triflorum: A Novel Approach Towards Weed Utilization.

    PubMed

    Ahmad, Naheed; Sharma, Seema; Singh, V N; Shamsi, S F; Fatma, Anjum; Mehta, B R

    2011-01-01

    A single-step environmental friendly approach is employed to synthesize silver nanoparticles. The biomolecules found in plants induce the reduction of Ag(+) ions from silver nitrate to silver nanoparticles (AgNPs). UV-visible spectrum of the aqueous medium containing silver ions demonstrated a peak at 425?nm corresponding to the plasmon absorbance of silver nanoparticles. Transmission electron microscopy (TEM) showed the formation of well-dispersed silver nanoparticles in the range of 5-20?nm. X-ray diffraction (XRD) spectrum of the AgNPs exhibited 2? values corresponding to the silver nanocrystal. The process of reduction is extracellular and fast which may lead to the development of easy biosynthesis of silver nanoparticles. Plants during glycolysis produce a large amount of H(+) ions along with NAD which acts as a strong redoxing agent; this seems to be responsible for the formation of AgNPs. Water-soluble antioxidative agents like ascorbic acids further seem to be responsible for the reduction of AgNPs. These AgNPs produced show good antimicrobial activity against common pathogens. PMID:21350660

  19. Biosynthesis of Silver Nanoparticles from Desmodium triflorum: A Novel Approach Towards Weed Utilization

    PubMed Central

    Ahmad, Naheed; Sharma, Seema; Singh, V. N.; Shamsi, S. F.; Fatma, Anjum; Mehta, B. R.

    2011-01-01

    A single-step environmental friendly approach is employed to synthesize silver nanoparticles. The biomolecules found in plants induce the reduction of Ag+ ions from silver nitrate to silver nanoparticles (AgNPs). UV-visible spectrum of the aqueous medium containing silver ions demonstrated a peak at 425?nm corresponding to the plasmon absorbance of silver nanoparticles. Transmission electron microscopy (TEM) showed the formation of well-dispersed silver nanoparticles in the range of 5–20?nm. X-ray diffraction (XRD) spectrum of the AgNPs exhibited 2? values corresponding to the silver nanocrystal. The process of reduction is extracellular and fast which may lead to the development of easy biosynthesis of silver nanoparticles. Plants during glycolysis produce a large amount of H+ ions along with NAD which acts as a strong redoxing agent; this seems to be responsible for the formation of AgNPs. Water-soluble antioxidative agents like ascorbic acids further seem to be responsible for the reduction of AgNPs. These AgNPs produced show good antimicrobial activity against common pathogens. PMID:21350660

  20. Fabrication and characterization of silver nanoparticles using Delonix elata leaf broth.

    PubMed

    Sathiya, C K; Akilandeswari, S

    2014-07-15

    The synthesis of nanoparticles from plant sources has proved to be an effective and alternative method for the novel production of nanoparticles. This paper reports the bioreduction of silver nitrate into silver nanoparticle by the leaf extract of Delonix elata. The synthesized silver nanoparticles were characterized by UV-visible (UV-vis) spectroscopy, Fourier infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS), high resolution transmission electron microscope (HRTEM). In addition the size of the NPs was calculated by using Malvern Zetasizer and the stability by zeta potential. UV-vis spectra show the surface plasmon resonance (SPR) at 432 nm. This reveals the reduction of silver ions (Ag(+)) into silver (Ag°) and indicating the formation of silver nanoparticles (AgNPs). SEM analysis revealed the spherical shape of the particles with sizes in the range of 35-45 nm and EDS spectrum confirmed the presence of silver along with other elements in the plant metabolite. The XRD analysis showed that the AgNPs are crystalline in nature and have face-centered cubic structure. FT-IR spectra show the existence of biomolecules responsible for the reduction of silver nitrate. The size of the AgNPs estimated from particle size distribution curve shows the 70 nm. The zeta potential of AgNPs was found to be -18 mV, indicating the dispersion and stability. PMID:24681317

  1. Synchrotron Speciation of Silver and Zinc Oxide Nanoparticles Aged in a Kaolin Suspension

    SciTech Connect

    Scheckel, Kirk G.; Luxton, Todd P.; El Badawy, Amro M.; Impellitteri, Christopher A.; Tolaymat, Thabet M. (EPA); (UCIN)

    2010-07-23

    Assessments of the environmental fate and mobility of nanoparticles must consider the behavior of nanoparticles in relevant environmental systems that may result in speciation changes over time. Environmental conditions may act on nanoparticles to change their size, shape, and surface chemistry. Changing these basic characteristics of nanoparticles may result in a final reaction product that is significantly different than the initial nanomaterial. As such, basing long-term risk and toxicity on the initial properties of a nanomaterial may lead to erroneous conclusions if nanoparticles change upon release to the environment. The influence of aging on the speciation and chemical stability of silver and zinc oxide nanoparticles in kaolin suspensions was examined in batch reactors for up to 18 months. Silver nanoparticles remained unchanged in sodium nitrate suspensions; however, silver chloride was identified with the metallic silver nanoparticles in sodium chloride suspensions and may be attributed to an in situ silver chloride surface coating. Zinc oxide nanoparticles were rapidly converted via destabilization/dissolution mechanisms to Zn{sup 2+} inner-sphere sorption complexes within 1 day of reaction and these sorption complexes were maintained through the 12 month aging processes. Chemical and physical alteration of nanomaterials in the environment must be examined to understand fate, mobility, and toxicology.

  2. Myco-synthesis of silver nanoparticles using Beauveria bassiana against dengue vector, Aedes aegypti (Diptera: Culicidae).

    PubMed

    Banu, A Najitha; Balasubramanian, C

    2014-08-01

    The efficacy of silver synthesized biolarvicide with the help of entomopathogenic fungus, Beauveria bassiana, was assessed against the different larval instars of dengue vector, Aedes aegypti. The silver nanoparticles were observed and characterized by a scanning electron microscope (SEM) and energy-dispersive X-ray (EDX). A surface plasmon resonance band was observed at 420 nm in UV-vis spectrophotometer. The characterization was confirmed by shape (spherical), size 36.88-60.93 nm, and EDX spectral peak at 3 keV of silver nanoparticles. The synthesized silver nanoparticles have been tested against the different larval instars of Ae. aegypti at different concentrations for a period of 24 h. Ae. aegypti larvae were found more susceptible to the synthesized silver nanoparticles. The LC50 and LC90 values are 0.79 and 1.09 ppm with respect to the Ae. aegypti treated with B. bassiana (Bb) silver nanoparticles (AgNPs). First and second instar larvae of Ae. aegypti have shown cent percent mortality while third and fourth instars found 50.0, 56.6, 70.0, 80.0, and 86.6 and 52.4, 60.0, 68.5, 76.0, and 83.3% mortality at 24 h of exposure in 0.06 and 1.00 ppm, respectively. It is suggested that the entomopathogenic fungus synthesized silver nanoparticles would be appropriate for environmentally safer and greener approach for new leeway in vector control strategy through a biological process. PMID:24861012

  3. Electron transfer in peptides: on the formation of silver nanoparticles.

    PubMed

    Kracht, Sonja; Messerer, Matthias; Lang, Matthieu; Eckhardt, Sonja; Lauz, Miriam; Grobéty, Bernard; Fromm, Katharina M; Giese, Bernd

    2015-03-01

    Some microorganisms perform anaerobic mineral respiration by reducing metal ions to metal nanoparticles, using peptide aggregates as medium for electron transfer (ET). Such a reaction type is investigated here with model peptides and silver as the metal. Surprisingly, Ag(+) ions bound by peptides with histidine as the Ag(+)-binding amino acid and tyrosine as photoinducible electron donor cannot be reduced to Ag nanoparticles (AgNPs) under ET conditions because the peptide prevents the aggregation of Ag atoms to form AgNPs. Only in the presence of chloride ions, which generate AgCl microcrystals in the peptide matrix, does the synthesis of AgNPs occur. The reaction starts with the formation of 100?nm Ag@AgCl/peptide nanocomposites which are cleaved into 15?nm AgNPs. This defined transformation from large nanoparticles into small ones is in contrast to the usually observed Ostwald ripening processes and can be followed in detail by studying time-resolved UV/Vis spectra which exhibit an isosbestic point. PMID:25663127

  4. Studies on the chemical synthesis and characterization of lead oxide nanoparticles with different organic capping agents

    SciTech Connect

    Arulmozhi, K. T., E-mail: arulsheelphy@gmail.com [Physics Wing (DDE), Annamalai University, Tamil Nadu, India - 608 002 (India); Mythili, N. [Department of Physics, Annamalai University, Tamil Nadu, India - 608 002 (India)] [Department of Physics, Annamalai University, Tamil Nadu, India - 608 002 (India)

    2013-12-15

    Lead oxide (PbO) nanoparticles were chemically synthesized using Lead (II) acetate as precursor. The effects of organic capping agents such as Oleic acid, Ethylene Diamine Tetra Acetic acid (EDTA) and Cetryl Tri Methyl Butoxide (CTAB) on the size and morphology of the nanoparticles were studied. Characterization techniques such as X-ray diffraction (XRD), Fourier Transform-Infrared spectroscopy (FT-IR), Photoluminescence (PL) Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy (TEM) were used to analyse the prepared nanoparticles for their physical, structural and optical properties. The characterization studies reveal that the synthesized PbO nanoparticles had well defined crystalline structure and sizes in the range of 25 nm to 36 nm for capping agents used and 40 nm for pure PbO nanoparticles.

  5. Biocidal effects of silver and zinc oxide nanoparticles on the bioluminescent bacteria

    NASA Astrophysics Data System (ADS)

    Taran, M. V.; Starodub, N. F.; Katsev, A. M.; Guidotti, M.; Khranovskyy, V. D.; Babanin, A. A.; Melnychuk, M. D.

    2013-11-01

    The effect of silver and zinc oxide nanoparticles in combination with alginate on bioluminescent Photobacterium leiognathi Sh1 bacteria was investigated. Silver nanoparticles were found to be more toxic than zinc oxide nanoparticles on bioluminescent bacteria. The nanoparticles and their ions released results in the same effect, however, it was absent in combination with alginate. The effective inhibiting concentration (EC50) for silver nanoparticles was found about 0.3 - 0.4 ?g mL-1, which was up to two times larger then for zinc oxide nanoparticles. The absence of sodium chloride in the tested media prevented the formation of colloidal particles of larger size and the effective inhibition concentrations of metal derivatives were lower than in the presence of sodium chloride.

  6. Synthesis of silver nanoparticles by using tea leaf extract from Camellia sinensis.

    PubMed

    Loo, Yuet Ying; Chieng, Buong Woei; Nishibuchi, Mitsuaki; Radu, Son

    2012-01-01

    The development of the biological synthesis of nanoparticles using microorganisms or plant extracts plays an important role in the field of nanotechnology as it is environmentally friendly and does not involve any harmful chemicals. In this study, the synthesis of silver nanoparticles using the leaves extract of Chinese tea from Camellia sinensis is reported. The synthesized nanoparticles were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The XRD analysis shows that the synthesized silver nanoparticles are of face-centered cubic structure. Well-dispersed silver nanoparticles with an approximate size of 4 nm were observed in the TEM image. The application of the green synthesized nanoparticles can be used in many fields such as cosmetics, foods, and medicine. PMID:22904632

  7. Synthesis of silver nanoparticles by using tea leaf extract from Camellia Sinensis

    PubMed Central

    Loo, Yuet Ying; Chieng, Buong Woei; Nishibuchi, Mitsuaki; Radu, Son

    2012-01-01

    The development of the biological synthesis of nanoparticles using microorganisms or plant extracts plays an important role in the field of nanotechnology as it is environmentally friendly and does not involve any harmful chemicals. In this study, the synthesis of silver nanoparticles using the leaves extract of Chinese tea from Camellia sinensis is reported. The synthesized nanoparticles were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The XRD analysis shows that the synthesized silver nanoparticles are of face-centered cubic structure. Well-dispersed silver nanoparticles with an approximate size of 4 nm were observed in the TEM image. The application of the green synthesized nanoparticles can be used in many fields such as cosmetics, foods, and medicine. PMID:22904632

  8. Investigation of antibacterial properties silver nanoparticles prepared via green method

    PubMed Central

    2012-01-01

    Background This study aims to investigate the influence of different stirring times on antibacterial activity of silver nanoparticles in polyethylene glycol (PEG) suspension. The silver nanoparticles (Ag-NPs) were prepared by green synthesis method using green agents, polyethylene glycol (PEG) under moderate temperature at different stirring times. Silver nitrate (AgNO3) was taken as the metal precursor while PEG was used as the solid support and polymeric stabilizer. The antibacterial activity of different sizes of nanosilver was investigated against Gram–positive [Staphylococcus aureus] and Gram–negative bacteria [Salmonella typhimurium SL1344] by the disk diffusion method using Müeller–Hinton Agar. Results Formation of Ag-NPs was determined by UV–vis spectroscopy where surface plasmon absorption maxima can be observed at 412–437 nm from the UV–vis spectrum. The synthesized nanoparticles were also characterized by X-ray diffraction (XRD). The peaks in the XRD pattern confirmed that the Ag-NPs possessed a face-centered cubic and peaks of contaminated crystalline phases were unable to be located. Transmission electron microscopy (TEM) revealed that Ag-NPs synthesized were in spherical shape. The optimum stirring time to synthesize smallest particle size was 6 hours with mean diameter of 11.23 nm. Zeta potential results indicate that the stability of the Ag-NPs is increases at the 6 h stirring time of reaction. The Fourier transform infrared (FT-IR) spectrum suggested the complexation present between PEG and Ag-NPs. The Ag-NPs in PEG were effective against all bacteria tested. Higher antibacterial activity was observed for Ag-NPs with smaller size. These suggest that Ag-NPs can be employed as an effective bacteria inhibitor and can be applied in medical field. Conclusions Ag-NPs were successfully synthesized in PEG suspension under moderate temperature at different stirring times. The study clearly showed that the Ag-NPs with different stirring times exhibit inhibition towards the tested gram-positive and gram-negative bacteria. PMID:22839208

  9. Photochemical and antimicrobial properties of silver nanoparticle-encapsulated chitosan functionalized with photoactive groups.

    PubMed

    Mathew, Thomas V; Kuriakose, Sunny

    2013-10-01

    Chitosan was functionalized with 4-((E)-2-(3-hydroxynaphthalen-2-yl)diazen-1-yl)benzoic acid by the coupling of the hydroxyl functional groups of chitosan with carboxylic acid group of the dye by DCC coupling method. The silver nanoparticles were prepared by sol-gel method of nanoparticle synthesis. Silver nanoparticle-encapsulated functionalized chitosan was prepared by the phase transfer method. The products were characterized by FTIR, UV-Vis, fluorescence and NMR spectroscopic methods and by SEM and TEM analysis. The photochemical properties of silver nanoparticle-encapsulated chitosan functionalized with 4-((E)-2-(3-hydroxynaphthalen-2-yl)diazen-1-yl)benzoic acid was studied in detail. The light-fastening properties of the chromophoric system was enhanced when attached to chitosan, and it can be further improved by the encapsulation of silver nanoparticles. The antibacterial analysis of silver nanoparticle-encapsulated functionalized chitosan was carried out against Staphylococcus aureus and Escherichia coli and against fungal species such as Aspergillus flavus and Aspergillus terreus. This study showed that silver nanoparticles-encapsulated functionalized chitosan can be used for antibacterial and antifungal applications. PMID:23910360

  10. The relationship between the antimicrobial effect of catheter coatings containing silver nanoparticles and the coagulation of contacting blood

    Microsoft Academic Search

    Kris N. J. Stevens; Olga Crespo-Biel; Edith E. M. van den Bosch; Aylvin A. Dias; Menno L. W. Knetsch; Yvette B. J. Aldenhoff; Frederik H. van der Veen; Jos G. Maessen; Ellen E. Stobberingh; Leo H. Koole

    2009-01-01

    It is well known that surface coatings for medical devices can be made antimicrobial through introduction of silver nanoparticles. By virtue of their extremely large surface-to-volume ratio, the silver particles serve as a depot for sustained release of silver ions, despite the fact that silver is not readily oxidized. Antimicrobial coatings are especially important in connection with indwelling catheters with

  11. Characterization, antioxidant and cytotoxicity evaluation of green synthesized silver nanoparticles using Cleistanthus collinus extract as surface modifier

    SciTech Connect

    Kanipandian, Nagarajan [Laboratory of Aquabiotics/Nanoscience, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu (India); Kannan, Soundarapandian [Proteomics and Molecular Cell Physiology Laboratory, Department of Zoology, Periyar University, Salem 636 011, Tamil Nadu (India); Ramesh, Ramar; Subramanian, Periyasamy [Laboratory of Aquabiotics/Nanoscience, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu (India); Thirumurugan, Ramasamy, E-mail: ramthiru72@gmail.com [Laboratory of Aquabiotics/Nanoscience, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu (India)

    2014-01-01

    Graphical abstract: The figure is the TEM image of green synthesized silver nanoparticles from Cleistanthus collinus. In this investigation we have used the poisonous plant as a reducing and capping agent. This is a first time data to synthesis the metal nanoparticles using poisonous plant. - Highlights: • A hitherto unreported venomous plant mediated AgNPs synthesis. • The particle size is observed in the range of 20–40 nm. • Surface morphology of the well-dispersed silver nanoparticles is studied using SEM and TEM. • Crystalline nature of AgNPs is confirmed by X-ray diffraction analysis. • Antioxidant activities of green synthesized AgNPs are tested in vitro. - Abstract: We report, here a simple green method for the preparation of silver nanoparticles (AgNPs) using the plant extract of Cleistanthus collinus as potential phyto reducer. The synthesized AgNPs were characterized by UV–vis spectra, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The obtained results confirmed that the AgNPs were crystalline in nature and the morphological studies reveal the spherical shape of AgNPs with size ranging from 20 to 40 nm. The in vitro antioxidant activity of AgNPs showed a significant effect on scavenging of free radicals. The cytotoxicity study exhibited a dose-dependent effect against human lung cancer cells (A549) and normal cells (HBL-100), the inhibitory concentration (IC{sub 50}) were found to be 30 ?g/mL and 60 ?g/mL respectively. The in vivo histopathology of mouse organs proved that AgNPs does not possess toxic effect and can be extensively applied in biomedical sciences.

  12. An evaluation of the influence of size and radiation in silver nanoparticle toxicity

    EPA Science Inventory

    The antimicrobial properties of silver nanoparticles (AgNP) have made them popular in textile manufacturing, medical technology, and biomedical applications. Studies suggest that after ingestion, nanomaterials are distributed throughout the body to different organs, possibly incl...

  13. Alterations in Physical State of Silver Nanoparticles Exposed to Synthetic Human Stomach Fluid

    EPA Science Inventory

    The bioavailability of ingested silver nanoparticles (AgNPs) depends in large part on initial particle size, shape and surface coating, properties which will influence aggregation, solubility and chemical composition during transit of the gastrointestinal tract. Citrate-stabilize...

  14. Facile Synthesis of Silver Nanoparticles Under {gamma}-Irradiation: Effect of Chitosan Concentration

    SciTech Connect

    Huang, N. M.; Radiman, S.; Ahmad, A.; Idris, H. [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi (Malaysia); Lim, H. N. [Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Khiew, P. S.; Chiu, W. S.; Tan, T. K. [Faculty of Engineering and Computer Science, Nottingham University, 43500 Semenyih (Malaysia)

    2009-06-01

    In the present study, a biopolymer, low molecular weight chitosan had been utilized as a 'green' stabilizing agent for the synthesis of silver nanoparticles under {gamma}-irradiation. The as-synthesized silver nanoparticles have particle diameters in the range of 5 nm-30 nm depending on the percentage of chitosan used (0.1 wt%, 0.5 wt%, 1.0 wt% and 2.0 wt%). It was found that the yield of the silver nanoparticles was in accordance with the concentration of chitosan presence in the solution due to the reduction by the chitosan radical during irradiation. The highly stable chitosan encapsulated silver nanoparticles were characterized using transmission electron microscopy (TEM), UV-Visible spectrophotometer (UV-VIS) and X-ray diffraction spectroscopy (XRD)

  15. Synthesis of silver nanoparticles using reducing agents obtained from natural sources ( Rumex hymenosepalus extracts)

    NASA Astrophysics Data System (ADS)

    Rodríguez-León, Ericka; Iñiguez-Palomares, Ramón; Navarro, Rosa Elena; Herrera-Urbina, Ronaldo; Tánori, Judith; Iñiguez-Palomares, Claudia; Maldonado, Amir

    2013-07-01

    We have synthesized silver nanoparticles from silver nitrate solutions using extracts of Rumex hymenosepalus, a plant widely found in a large region in North America, as reducing agent. This plant is known to be rich in antioxidant molecules which we use as reducing agents. Silver nanoparticles grow in a single-step method, at room temperature, and with no addition of external energy. The nanoparticles have been characterized by ultraviolet-visible spectroscopy and transmission electron microscopy, as a function of the ratio of silver ions to reducing agent molecules. The nanoparticle diameters are in the range of 2 to 40 nm. High-resolution transmission electron microscopy and fast Fourier transform analysis show that two kinds of crystal structures are obtained: face-centered cubic and hexagonal.

  16. Micro-Raman Spectroscopy of Silver Nanoparticle Induced Stress on Optically-Trapped Stem Cells

    PubMed Central

    Bankapur, Aseefhali; Krishnamurthy, R. Sagar; Zachariah, Elsa; Santhosh, Chidangil; Chougule, Basavaraj; Praveen, Bhavishna; Valiathan, Manna; Mathur, Deepak

    2012-01-01

    We report here results of a single-cell Raman spectroscopy study of stress effects induced by silver nanoparticles in human mesenchymal stem cells (hMSCs). A high-sensitivity, high-resolution Raman Tweezers set-up has been used to monitor nanoparticle-induced biochemical changes in optically-trapped single cells. Our micro-Raman spectroscopic study reveals that hMSCs treated with silver nanoparticles undergo oxidative stress at doping levels in excess of 2 µg/ml, with results of a statistical analysis of Raman spectra suggesting that the induced stress becomes more dominant at nanoparticle concentration levels above 3 µg/ml. PMID:22514708

  17. Fluorescent protein capped mesoporous nanoparticles for intracellular drug delivery and imaging.

    PubMed

    Yang, Xinjian; Li, Zhenhua; Li, Meng; Ren, Jinsong; Qu, Xiaogang

    2013-11-01

    A multifunctional system for intracellular drug delivery and simultaneous fluorescent imaging was constructed by using histidine-tagged, cyan fluorescent protein (CFP)-capped magnetic mesoporous silica nanoparticles (MMSNs). This protein-capped multifunctional nanostructure is highly biocompatible and does not affect cell viability or proliferation. The CFP acts not only as a capping agent, but also as a fluorescent imaging agent. The nanoassembly was activated by histidine-based replacement, leading to release of drug molecules encapsulated in the nanopores into the bulk solution. The fluorescent imaging functionality would allow noninvasive tracking of the nanoparticles in the body. By combining the drug delivery with cell-imaging capability, these nanoparticles may provide valuable multifunctional nanoplatforms for biomedical applications. PMID:24108691

  18. Synthesis of Gold and Silver Nanoparticles Stabilized with Glycosaminoglycans having Distinctive Biological Activities

    PubMed Central

    Kemp, Melissa M.; Kumar, Ashavani; Mousa, Shaymaa; Park, Tae-Joon; Ajayan, Pulickel; Kubotera, Natsuki; Mousa, Shaker

    2009-01-01

    Metal nanoparticles have been studied for their anticoagulant and anti-inflammatory efficacy in various models. Specifically, gold and silver nanoparticles exhibit properties that make these ideal candidates for biological applications. The typical synthesis of gold and silver nanoparticles incorporates contaminants that could pose further problems. Here we demonstrate a clean method of synthesizing gold and silver nanoparticles that exhibit biological functions. These nanoparticles were prepared by reducing AuCl4 and AgNO3 using heparin and hyaluronan, as both reducing and stabilizing agents. The particles show stability under physiological conditions, and narrow size distributions for heparin particles and wider distribution for hyaluronan particles. Studies show that the heparin nanoparticles exhibit anticoagulant properties. Additionally, either gold- or silver- heparin nanoparticles exhibit local anti-inflammatory properties without any significant effect on systemic hemostasis upon administration in carrageenan-induced paw edema models. In conclusion, gold and silver nanoparticles complexed with heparin demonstrated effective anticoagulant and anti-inflammatory efficacy, having potential in various local applications. PMID:19226107

  19. Spectroscopic and fluorescence properties of silver-dye composite nanoparticles

    NASA Astrophysics Data System (ADS)

    Laban, B. B.; Vodnik, V.; Vuja?i?, A.; Sovilj, S. P.; Joki?, A. B.; Vasi?, V.

    2013-12-01

    The aim of this work was to investigate the formation of J-aggregates of thiacyanine dye (TC, 5,5'-disulfopropyl-3,3'-dichlorothiacyanine sodium salt) in the presence of 6 nm spherical silver nanoparticles (Ag NPs) using spectrophotometric and fluorescence methods. The formation of J-aggregates was concentration dependent and characterized by the appearance of the new absorption band with the maximum at 481 nm. Spectrophotometric study of J-aggregate formation and time stability suggested that they were formed on the account of monomer form of TC. Moreover, the stability of J-aggregates increased with the lowering AgNPs concentration. The measurements of fluorescence of the NPs—dye assembly clearly indicated that the fluorescence of TC was quenched by Ag NPs on the concentration dependent manner. The spectrophotometric and fluorescence properties of NPs—dye assembly were found to be quantitatively related to the surface coverage of the dye on the Ag NPs.

  20. Synthesis and Antimicrobial Activity of Silver-Doped Hydroxyapatite Nanoparticles

    PubMed Central

    Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Chifiriuc, Mariana Carmen; Costescu, Adrian; Le Coustumer, Philippe; Predoi, Daniela

    2013-01-01

    The synthesis of nanosized particles of Ag-doped hydroxyapatite with antibacterial properties is of great interest for the development of new biomedical applications. The aim of this study was the evaluation of Ca10?xAgx(PO4)6(OH)2 nanoparticles (Ag:HAp-NPs) for their antibacterial and antifungal activity. Resistance to antimicrobial agents by pathogenic bacteria has emerged in the recent years and became a major health problem. Here, we report a method for synthesizing Ag doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionised water. Also, in this paper Ag:HAp-NPs are evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria and fungal strains. The specific antimicrobial activity revealed by the qualitative assay is demonstrating that our compounds are interacting differently with the microbial targets, probably due to the differences in the microbial wall structures. PMID:23509801

  1. Proteomics study of silver nanoparticles toxicity on Bacillus thuringiensis.

    PubMed

    Mirzajani, Fateme; Askari, Hossein; Hamzelou, Sara; Schober, Yvonne; Römpp, Andreas; Ghassempour, Alireza; Spengler, Bernhard

    2014-02-01

    Emerging technologies in functional genomics and proteomics provide a way of achieving high-throughput analyses, understanding effects on protein populations and sub-populations and follow up environmental stresses. To accomplish these, the action of homemade spherical Silver nanoparticles colloidal suspension (AgNPs) against Bacillus thuringiensis (isolate from Oryza sativa L. rhizosphere) was investigated by a proteomic approach (2-DE and NanoLC/FT-ICR MS identification). Thirty four responsive (up/down regulated) proteins were identified. Proteomic results revealed that an exposure of B. thuringiensis cells with different concentrations of AgNPs resulted in an accumulation of envelope protein precursors, indicative of the dissipation of a proton motive force. Identified proteins are involved in oxidative stress tolerance, metal detoxification, transcription and elongation processes, protein degradation, cytoskeleton remodeling and cell division. The expression pattern of these proteins and their possible involvement in the nontoxicity mechanisms were discussed. PMID:24290895

  2. Effect of CNT decoration with silver nanoparticles on electrical conductivity of CNT-polymer composites

    Microsoft Academic Search

    Peng Cheng Ma; Ben Zhong Tang; Jang-Kyo Kim

    2008-01-01

    A simple approach to decorate carbon nanotube (CNT) with silver nanoparticles (Ag-NPs) was developed to enhance the electrical conductivity of CNT. CNTs were functionalized using ball milling in the presence of ammonium bicarbonate, followed by reduction of silver ions in N, N-dimethylformamide, producing silver decorated CNTs (Ag@CNTs). The Ag@CNTs were employed as conducting filler in epoxy resin to fabricate electrically

  3. UV-induced synthesis, characterization and formation mechanism of silver nanoparticles in alkalic carboxymethylated chitosan solution

    Microsoft Academic Search

    Ling Huang; Maolin L. Zhai; Dewu W. Long; Jing Peng; Ling Xu; Guozhong Z. Wu; Jiuqiang Q. Li; Genshuan S. Wei

    2008-01-01

    The silver nanoparticles (AgNPs) were synthesized in an alkalic aqueous solution of silver nitrate (AgNO3)\\/carboxymethylated chitosan (CMCTS) with ultraviolet (UV) light irradiation. CMCTS, a water-soluble and biocompatible chitosan\\u000a derivative, served simultaneously as a reducing agent for silver cation and a stabilizing agent for AgNPs in this method.\\u000a UV–vis spectra and transmission electron microscopy (TEM) images analyses showed that the pH

  4. Radiolytically induced formation and optical absorption spectra of colloidal silver nanoparticles in supercritical ethane

    Microsoft Academic Search

    Nada M. Dimitrijevic; David M. Bartels; Charles D. Jonah; Kenji Takahashi; Tijana Rajh

    2001-01-01

    Colloidal silver nanoparticles were synthesized in supercritical ethane at 80 {sup o}C and 80-120 bar, with methanol as cosolvent. Solvated electrons, produced by a pulse of 20 MeV electrons, reduced the silver ions. The time-resolved technique of pulse radiolysis was employed to characterize the reduction products and colloidal metallic particles. The absorption spectra of small silver clusters (Agâ{sup +}, Agâ{sup

  5. Biogenic silver nanoparticles: efficient and effective antifungal agents

    NASA Astrophysics Data System (ADS)

    Netala, Vasudeva Reddy; Kotakadi, Venkata Subbaiah; Domdi, Latha; Gaddam, Susmila Aparna; Bobbu, Pushpalatha; Venkata, Sucharitha K.; Ghosh, Sukhendu Bikash; Tartte, Vijaya

    2015-06-01

    Biogenic synthesis of silver nanoparticles (AgNPs) by exploiting various plant materials is an emerging field and considered green nanotechnology as it involves simple, cost effective and ecofriendly procedure. In the present study AgNPs were successfully synthesized using aqueous callus extract of Gymnema sylvestre. The aqueous callus extract treated with 1nM silver nitrate solution resulted in the formation of AgNPs and the surface plasmon resonance (SPR) of the formed AgNPs showed a peak at 437 nm in the UV Visible spectrum. The synthesized AgNPs were characterized using Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), and X-ray diffraction spectroscopy (XRD). FTIR spectra showed the peaks at 3333, 2928, 2361, 1600, 1357 and 1028 cm-1 which revealed the role of different functional groups possibly involved in the synthesis and stabilization of AgNPs. TEM micrograph clearly revealed the size of the AgNPs to be in the range of 3-30 nm with spherical shape and poly-dispersed nature; it is further confirmed by Particle size analysis that the stability of AgNPs is due its high negative Zeta potential (-36.1 mV). XRD pattern revealed the crystal nature of the AgNPs by showing the braggs peaks corresponding to (111), (200), (220) and (311) planes of face-centered cubic crystal phase of silver. Selected area electron diffraction pattern showed diffraction rings and confirmed the crystalline nature of synthesized AgNPs. The synthesized AgNPs exhibited effective antifungal activity against Candida albicans, Candida nonalbicans and Candida tropicalis.

  6. Comparative analysis of biosynthesised and chemosynthesised silver nanoparticles with special reference to their antibacterial activity against pathogens.

    PubMed

    Bawskar, Manisha; Deshmukh, Shivaji; Bansod, Sunita; Gade, Aniket; Rai, Mahendra

    2015-06-01

    The present study reports the synthesis of silver nanoparticles (AgNPs) using both biological and chemical routes to find out the best method for control of their size and activity. The fungal agent (Fusarium oxysporum) and the plant (Azadirachta indica) were found to be the best source for AgNPs synthesis. Both biosynthesis and chemosynthesis were achieved by challenging filtrate with AgNO3 (1 mM) solution. The synthesised nanoparticles were characterised by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, nanoparticle tracking analysis (LM20), zeta potential measurement and transmission electron microscopy. The biologically synthesised nanoparticles were spherical, polydispersed and in the range of 10-40 nm, while chemically synthesised nanoparticles were highly monodispersed with a size of 5 nm. The antimicrobial assay against Escherichia coli and Staphylococcus aureus proved biogenic AgNPs to be more potent antibacterial agents than chemically synthesised AgNPs. The possible antibacterial mechanism of AgNPs has also been discussed. Biogenic AgNPs have shown more activity because of the protein capping and their mode of entry into the bacterial cell. These findings may encourage the use of biosynthesis over the chemosynthesis method. PMID:26023154

  7. Biosynthesis, characterization and antimicrobial studies of green synthesized silver nanoparticles from fruit extract of Syzygium alternifolium (Wt.) Walp. an endemic, endangered medicinal tree taxon

    NASA Astrophysics Data System (ADS)

    Yugandhar, P.; Savithramma, N.

    2015-03-01

    In nanotechnology, the plant mediated synthesis of nanoparticles has terrific application in biomedicine due to its novel properties and its eco-friendly nature. The present study deals with the biosynthesis of stable silver nanoparticles (SNPs) from aqueous fruit extract of S. alternifolium an endemic medicinal plant to Eastern Ghats. The synthesized nanoparticles are characterized by UV-VIS spectroscopy, FTIR, XRD, AFM, SEM with EDAX and TEM. Colour change from brown to grey indicates the formation of nanoparticles and UV-VIS surface plasmon resonance spectroscopy observed at 442 nm further confirms the synthesized nanoparticles are SNPs. FTIR studies reveal that the phenols and primary amines of proteins are main responsible for reduction, stabilization and capping agents towards these SNPs. The XRD data show crystalline nature of nanoparticles and EDAX measurements reveal the (12.74 %) percentage presence of Ag metal. AFM, SEM and TEM microscopic analyses revealed that the size of synthesized SNPs ranging from 5 to 68 nm has spherical shape and they are in polydispersed condition. Further, the antimicrobial studies of synthesized SNPs show high toxicity towards different bacterial and fungal isolates. This is the first report on fruit mediated synthesis of silver nanoparticles from S. alternifolium.

  8. Mussel-adhesive-inspired fabrication of multifunctional silver nanoparticle assemblies.

    PubMed

    Xiong, Shuqiang; Wang, Yan; Zhu, Jing; Yu, Junrong; Hu, Zuming

    2015-05-19

    The assembly of metal nanoparticles (NPs) has attracted a great deal of attention recently because of their collective properties that could not be exhibited by individual NPs. Here a one-step approach was reported for the fabrication of spherical silver NP assemblies (AgNAs). The formation of AgNAs simply included the stirring of silver ammonia and 3,4-dihydroxy-l-phenylalanine (DOPA) in aqueous solution at room temperature, in which DOPA acted as a reductant for AgNPs first because of its reducing ability and then directed the assembly of AgNPs into AgNAs. The AgNAs exhibited hierarchical structure with controllable sizes ranging from 180 to 610 nm by adjusting the concentrations of reagents. The two individual components, AgNPs and polyDOPA, also allowed AgNAs with multiple functions as demonstrated in this study of durable catalytic activity, high SERS sensitivity, and good antioxidant properties. The thin polyDOPA layer coated on AgNAs further offered the opportunity to modify the surface of AgNAs. The results presented here may provide a green and facile approach to designing multifunctional NP assemblies. PMID:25919224

  9. Synthesis of silver nanoparticles in montmorillonite and their antibacterial behavior

    PubMed Central

    Shameli, Kamyar; Ahmad, Mansor Bin; Zargar, Mohsen; Yunus, Wan Md Zin Wan; Rustaiyan, Abdolhossein; Ibrahim, Nor Azowa

    2011-01-01

    Silver nanoparticles (Ag NPs) were synthesized by the chemical reducing method in the external and interlamellar space of montmorillonite (MMT) as a solid support at room temperature. AgNO3 and NaBH4 were used as a silver precursor and reducing agent, respectively. The most favorable experimental conditions for synthesizing Ag NPs in the MMT are described in terms of the initial concentration of AgNO3. The interlamellar space limits changed little (d-spacing = 1.24–1.47 nm); therefore, Ag NPs formed on the MMT suspension with d-average = 4.19–8.53 nm diameter. The Ag/MMT nanocomposites (NCs), formed from AgNO3/MMT suspension, were characterizations with different instruments, for example UV-visible, PXRD, TEM, SEM, EDXRF, FT-IR, and ICP-OES analyzer. The antibacterial activity of different sizes of Ag NPs in MMT were investigated against Gram-positive, ie, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) and Gram-negative bacteria, ie, Escherichia coli, Escherichia coli O157:H7, and Klebsiella pneumoniae, by the disk diffusion method using Mueller-Hinton agar (MHA). The smaller Ag NPs were found to have significantly higher antibacterial activity. These results showed that Ag NPs can be used as effective growth inhibitors in different biological systems, making them applicable to medical applications. PMID:21674015

  10. Substrate decomposition in galvanic displacement reaction: Contrast between gold and silver nanoparticle formation

    NASA Astrophysics Data System (ADS)

    Ghosh, Tapas; Kabiraj, D.; Satpati, Biswarup

    2015-06-01

    We have investigated substrate decomposition during formation of silver and gold nanoparticles in galvanic displacement reaction on germanium surfaces. Silver and gold nanoparticles were synthesized by electroless deposition on sputter coated germanium thin film (˜ 200 nm) grown initially on silicon substrate. The naoparticles formation and the substrate corrosion were studied using scanning transmission electron microscopy (STEM) and the energy dispersive X-ray (EDX) spectroscopy.

  11. SiO2 coating of silver nanoparticles by photoinduced chemical vapor deposition

    Microsoft Academic Search

    Adam M. Boies; Jeffrey T. Roberts; Steven L. Girshick; Bin Zhang; Toshitaka Nakamura; Amane Mochizuki

    2009-01-01

    Gas-phase silver nanoparticles were coated with silicon dioxide (SiO2) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO2 precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO2 coatings on the particle surfaces.

  12. The general synthesis of Ag nanoparticles anchored on silver vanadium oxides: towards high

    E-print Network

    Cao, Guozhong

    , Ag2V4O11, Ag0.33V2O5 and Ag1.2V3O8. In brief, NH4VO3 powder rst reacts with H2O2 in de- ionized waterThe general synthesis of Ag nanoparticles anchored on silver vanadium oxides: towards high-pot synthesis of Ag nanoparticles uniformly anchored on silver vanadium oxides (SVOs) including AgVO3, Ag2V4O11

  13. Mechanism of silver nano-particles formation on ?-alumina using supercritical water

    Microsoft Academic Search

    Osamu Sawai; Yoshito Oshima

    2008-01-01

    Supercritical water impregnation is a novel method, which utilizes high diffusivity of the fluid with hydrothermal synthesis\\u000a allowing nano-particles to deposit on porous materials in well-dispersed condition. In this work, silver nano-particles were\\u000a deposited on the surface of ?-alumina supports using metal acetate solution. TEM-EDS analyses clearly identified the silver\\u000a particle of two kinds, those deposited on ?-alumina surface and

  14. Biosynthesis of silver nanoparticles using lingonberry and cranberry juices and their antimicrobial activity.

    PubMed

    Puišo, Judita; Jonkuvien?, Dovil?; Ma?ionien?, Irena; Šalomskien?, Joana; Jasutien?, Ina; Kondrotas, Rokas

    2014-09-01

    In this study lingonberry and cranberry juices were used for silver nanoparticle synthesis. The berry juices were characterized by total phenolics, total anthocyanins and benzoic acid content, respectively 1.9-2.7mg/ml, 55.2-83.4mg/l and 590.8-889.2mg/l. The synthesis of silver nanoparticles was performed at room temperature assisting in solutions irradiated by ultraviolet for 30min. Ultraviolet-visible (UV-vis) spectroscopy and microscopy confirmed the formation of nanoparticles as well as the dark red color of colloid of silver samples showed the formation of stable nanoparticles. Broad localized surface plasmon resonance (LSPR) peaks in UV-vis spectra indicated the formation of polydispersive silver nanoparticles and LSPR was observed at 485nm and 520nm for the silver nanoparticles synthesis using lingonberry and cranberry juices, respectively. The antimicrobial activity of silver nanoparticles was determined against the reference strains of microorganisms that could be found in food products: Staphylococcus aureus ATCC 25923, Salmonella typhimurium ATCC 13076, Listeria monocytogenes ATCC 19111, Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Bacillus subtilis ATCC 6633, Candida albicans ATCC 10231 and foodborne B. cereus producing and non-producing enterotoxins. Silver nanoparticles showed a broad spectrum of antimicrobial activity and were most active against S. aureus ATCC 25923, B. subtilis ATCC 6633 and B. cereus ATCC 11778 reference cultures, and less active against C. albicans ATCC 10231 and foodborne B. cereus. It can be concluded that lingonberry and cranberry juices could be used as bioreductants for silver ions. PMID:24988412

  15. Laser Curing of the Silver\\/Copper Nanoparticle Ink via Optical Property Measurement and Calculation

    Microsoft Academic Search

    Tae-Yeop Kim; Jun-Young Hwang; Seung-Jae Moon

    2010-01-01

    The spectral optical properties of the silver\\/copper nanoparticle ink at visible and near-infrared wavelength were measured by ellipsometry. The purpose of the measurement of the optical properties is to select the optimal process parameters such as working wavelength and laser incidence angle by finding the maximum absorption wavelength. The reflectance and absorptivity of the nano-ink including silver\\/copper nanoparticles were calculated

  16. Effect of cationization on adsorption of silver nanoparticles on cotton surfaces and its antibacterial activity

    Microsoft Academic Search

    Mohammad Shateri Khalil-Abad; Mohammad Esmail Yazdanshenas; Mohammad Reza Nateghi

    2009-01-01

    Cotton was cationized by exhaustion method using 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) as a cation-generating\\u000a agent. Adsorption of silver nanoparticles on normal and cationized cotton was studied by exhaustion method at temperatures\\u000a of 80°C and 100°C. Two exhaustion baths were used, containing nanosilver colloidal solutions stabilized by two different stabilizers\\u000a and various concentrations of silver nanoparticles. Fourier-transform infrared (FT-IR) spectra

  17. Thermal conductivity measurement of organic solvents incorporated with silver nanoparticle using photothermal techniques

    NASA Astrophysics Data System (ADS)

    Shemeena Basheer, N.; Kumar, B. Rajesh; Kurian, Achamma; George, Sajan D.

    2015-02-01

    The present paper summarizes our recent work on heat transfer of nanofluid in different organic solvents determined using photothermal techniques. UV- Visible absorption spectrum shows an intense surface plasmon absorption peak at 427 nm. TEM indicates the presence of well dispersed silver nanoparticles having spherical morphology with particle size ranging from 10 to13 nm. The experimental results show that thermal conductivity of organic solvents increases with the incorporation of silver nanoparticles.

  18. Importance of poly(ethylene glycol) conformation for the synthesis of silver nanoparticles in aqueous solution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the formation of silver nanoparticles (NPs) using silver nitrate in a poly(ethylene glycol) (PEG) aqueous solution, which acts as both a reducing and stabilizing agent, the PEG chain structure was found to play a significant role. Even though PEG 100 (100 kg/mol) has limited reducing sites of hyd...

  19. Silver Nanoparticles as Selective Ionization Probes for Analysis of Olefins by Mass Spectrometry

    E-print Network

    this effect to -cation interactions between tyrosine and the metal nano- particle. Here, we exploit the AgSilver Nanoparticles as Selective Ionization Probes for Analysis of Olefins by Mass Spectrometry/ionization (LDI) using silver nanopar- ticles (AgNPs) is shown to selectively ionize olefinic compounds, e

  20. Deposition of silver nano-particles on activated carbon using supercritical water

    Microsoft Academic Search

    Osamu Sawai; Yoshito Oshima

    2008-01-01

    Metal silver nano-particles were deposited on the surface and in the pores of activated carbon by supercritical water impregnation (SCWI). Deposited silver particles distributed similar mean particle size as in particles on ?-alumina support surface. Although the amount of particle deposition was relatively small compared to ?-alumina due to large surface area of carbon support, the particle size distributions exhibited

  1. Green Synthesized Silver Nanoparticles Exhibit Reduced Toxicity to Mammalian Cells and Retain Antimicrobial Activity

    EPA Science Inventory

    The interest in silver nanoparticles (AgNPs) and silver nanomaterial stems from their antimicrobial properties. AgNPs are being added to clothing, paint, refrigerators, washing machines and a variety of other commercially available items. Recent in vitro and in vivo studies, howe...

  2. Sweet Nanochemistry: A Fast, Reliable Alternative Synthesis of Yellow Colloidal Silver Nanoparticles Using Benign Reagents

    ERIC Educational Resources Information Center

    Cooke, Jason; Hebert, Dominique; Kelly, Joel A.

    2015-01-01

    This work describes a convenient and reliable laboratory experiment in nanochemistry that is flexible and adaptable to a wide range of educational settings. The rapid preparation of yellow colloidal silver nanoparticles is achieved by glucose reduction of silver nitrate in the presence of starch and sodium citrate in gently boiling water, using…

  3. A novel green synthesis of silver nanoparticles using soluble starch and its antibacterial activity

    PubMed Central

    Yakout, Sobhy M; Mostafa, Ashraf A

    2015-01-01

    A green method of Silver nanoparticles (AgNPs) preparation has been established. This method depends on reduction of silver nitrate with soluble starch. The formation of AgNPs was observed by the color change from colorless to dark brown through the starch addition into silver nitrate solution. It was observed that use of starch makes convenient method for the synthesis of silver nanoparticles and can reduce silver ions into the produced silver nanoparticles within one hour of reaction time without using any harsh conditions. The prepared silver nanoparticles were characterized by using UV-visible spectroscopy and evaluated for its antimicrobial activity. The synthesized green AgNPs showed a potential antibacterial activity that was stronger against Gram positive pathogenic bacteria (Staphylococus aureus and Streptococus pyogenes) than against Gram negative pathogenic bacteria (Salmonella typhi, Shigellasonnei and Pseudomonas aeruginosa). Inhibition zones diameter of antibacterial activity depends upon nanoparticles concentration as AgNPs exhibited greater inhibition zone for S.aureus (16.4 mm) followed by P. aeruginosa and S. pyogenes while the least activity was observed for S. typhi (10.4 mm) at 40 ?l/ disc. These results suggested that AgNPs can be used as an effective antiseptic agents in medical fields and process of synthesis creates new opportunities in process development for the synthesis of safe and eco-friendly AgNPs.

  4. Study of mechanism of enhanced antibacterial activity by green synthesis of silver nanoparticles.

    PubMed

    Parashar, Upendra Kumar; Kumar, Vinod; Bera, Tanmay; Saxena, Preeti S; Nath, Gopal; Srivastava, Sunil K; Giri, Rajiv; Srivastava, Anchal

    2011-10-14

    The extensive use of silver nanoparticles needs a synthesis process that is greener without compromising their properties. The present study describes a novel green synthesis of silver nanoparticles using Guava (Psidium guajava) leaf extract. In order to compare with the conventionally synthesized ones, we also prepared Ag-NPs by chemical reduction. Their optical and morphological characteristics were thoroughly investigated and tested for their antibacterial properties on Escherichia coli. The green synthesized silver nanoparticles showed better antibacterial properties than their chemical counterparts even though there was not much difference between their morphologies. Fourier transform infrared (FTIR) spectroscopic analysis of the used extract and as-synthesized silver nanoparticles suggests the possible reduction of Ag(+) by the water-soluble ingredients of the guava leaf like tannins, eugenol and flavonoids. The possible reaction mechanism for the reduction of Ag(+) has been proposed and discussed. The time-dependent electron micrographs and the simulation studies indicated that a physical interaction between the silver nanoparticles and the bacterial cell membrane may be responsible for this effect. Based on the findings, it seems very reasonable to believe that this greener way of synthesizing silver nanoparticles is not just an environmentally viable technique but it also opens up scope to improve their antibacterial properties. PMID:21918296

  5. Study of mechanism of enhanced antibacterial activity by green synthesis of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Parashar, Upendra Kumar; Kumar, Vinod; Bera, Tanmay; Saxena, Preeti S.; Nath, Gopal; Srivastava, Sunil K.; Giri, Rajiv; Srivastava, Anchal

    2011-10-01

    The extensive use of silver nanoparticles needs a synthesis process that is greener without compromising their properties. The present study describes a novel green synthesis of silver nanoparticles using Guava (Psidium guajava) leaf extract. In order to compare with the conventionally synthesized ones, we also prepared Ag-NPs by chemical reduction. Their optical and morphological characteristics were thoroughly investigated and tested for their antibacterial properties on Escherichia coli. The green synthesized silver nanoparticles showed better antibacterial properties than their chemical counterparts even though there was not much difference between their morphologies. Fourier transform infrared (FTIR) spectroscopic analysis of the used extract and as-synthesized silver nanoparticles suggests the possible reduction of Ag + by the water-soluble ingredients of the guava leaf like tannins, eugenol and flavonoids. The possible reaction mechanism for the reduction of Ag + has been proposed and discussed. The time-dependent electron micrographs and the simulation studies indicated that a physical interaction between the silver nanoparticles and the bacterial cell membrane may be responsible for this effect. Based on the findings, it seems very reasonable to believe that this greener way of synthesizing silver nanoparticles is not just an environmentally viable technique but it also opens up scope to improve their antibacterial properties.

  6. Magnetite and magnetite/silver core/shell nanoparticles with diluted magnet-like behavior

    SciTech Connect

    Garza-Navarro, Marco [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Torres-Castro, Alejandro, E-mail: alejandro.torrescs@uanl.edu.m [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon 66600 (Mexico); Gonzalez, Virgilio; Ortiz, Ubaldo [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, Cd. Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon 66600 (Mexico); De la Rosa, Elder [Centro de Investigaciones en Optica, A.P. 1-948, Leon Gto. 37160 (Mexico)

    2010-01-15

    In the present work is reported the use of the biopolymer chitosan as template for the preparation of magnetite and magnetite/silver core/shell nanoparticles systems, following a two step procedure of magnetite nanoparticles in situ precipitation and subsequent silver ions reduction. The crystalline and morphological characteristics of both magnetite and magnetite/silver core/shell nanoparticles systems were analyzed by high resolution transmission electron microscopy (HRTEM) and nanobeam diffraction patterns (NBD). The results of these studies corroborate the core/shell morphology and the crystalline structure of the magnetite core and the silver shell. Moreover, magnetization temperature dependent, M(T), measurements show an unusual diluted magnetic behavior attributed to the dilution of the magnetic ordering in the magnetite and magnetite/silver core/shell nanoparticles systems. - Graphical abstract: Biopolymer chitosan was used as stabilization media to synthesize both magnetite and magnetite/silver core/shell nanoparticles. Results of HRTEM and NBD patterns confirm core/shell morphology of the obtained nanoparticles. It was found that the composites show diluted magnet-like behavior.

  7. Twenty-eight-day inhalation toxicity study of silver nanoparticles in Sprague-Dawley rats.

    PubMed

    Ji, Jun Ho; Jung, Jae Hee; Kim, Sang Soo; Yoon, Jin-Uk; Park, Jung Duck; Choi, Byung Sun; Chung, Yong Hyun; Kwon, Il Hoon; Jeong, Jayoung; Han, Beom Seok; Shin, Jae Hyeg; Sung, Jae Hyuck; Song, Kyung Seuk; Yu, Il Je

    2007-08-01

    The antibacterial effect of silver nanoparticles has resulted in their extensive application in health, electronic, and home products. Thus, the exposed population continues to increase as the applications expand. Although previous studies on silver dust, fumes, and silver compounds have revealed some insights, little is yet known about the toxicity of nano-sized silver particles, where the size and surface area are recognized as important determinants for toxicity. Thus, the inhalation toxicity of silver nanoparticles is of particular concern to ensure the health of workers and consumers. However, the dispersion of inhalable ambient nano-sized particles has been an obstacle in evaluating the effect of the inhalation of nano-sized particles on the respiratory system. Accordingly, the present study used a device that generates silver nanoparticles by evaporation/condensation using a small ceramic heater. As such, the generator was able to distribute the desired concentrations of silver nanoparticles to chambers containing experimental animals. The concentrations and distribution of the nanoparticles with respect to size were also measured directly using a differential mobility analyzer and ultrafine condensation particle counter. Therefore, the inhalation toxicity of silver nanoparticles was tested over a period of 28 days. Eight-week-old rats, weighing about 283 g for the males and 192 g for the females, were divided into 4 groups (10 rats in each group): a fresh-air control, a low-dose group (1.73 x 10(4)/cm3), a middle-dose group (1.27 x 10(5)/cm3), and a high-dose group (1.32 x 10(6) particles/cm3, 61 microg/m3). The animals were exposed to the silver nanoparticles for 6 h/day, 5 days/wk, for a total of 4 wk. The male and female rats did not show any significant changes in body weight relative to the concentration of silver nanoparticles during the 28-day experiment. Plus, there were no significant changes in the hematology and blood biochemical values in either the male or female rats. Therefore, the initial results indicated that exposure to silver nanoparticles at a concentration near the current American Conference of Governmental Industrial Hygienists (ACGIH) silver dust limit (100 microg/m3) did not appear to have any significant health effects. PMID:17687717

  8. Chrysopogon zizanioides aqueous extract mediated synthesis, characterization of crystalline silver and gold nanoparticles for biomedical applications.

    PubMed

    Arunachalam, Kantha D; Annamalai, Sathesh Kumar

    2013-01-01

    The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The aim of this study was to develop a simple biological method for the synthesis of silver and gold nanoparticles using Chrysopogon zizanioides. To exploit various plant materials for the biosynthesis of nanoparticles was considered a green technology. An aqueous leaf extract of C. zizanioides was used to synthesize silver and gold nanoparticles by the bioreduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) respectively. Water-soluble organics present in the plant materials were mainly responsible for reducing silver or gold ions to nanosized Ag or Au particles. The synthesized silver and gold nanoparticles were characterized by ultraviolet (UV)-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. The kinetics decline reactions of aqueous silver/gold ion with the C. zizanioides crude extract were determined by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to the extract were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20-50 nm. This eco-friendly approach for the synthesis of nanoparticles is simple, can be scaled up for large-scale production with powerful bioactivity as demonstrated by the synthesized silver nanoparticles. The synthesized nanoparticles can have clinical use as antibacterial, antioxidant, as well as cytotoxic agents and can be used for biomedical applications. PMID:23861583

  9. Chrysopogon zizanioides aqueous extract mediated synthesis, characterization of crystalline silver and gold nanoparticles for biomedical applications

    PubMed Central

    Arunachalam, Kantha D; Annamalai, Sathesh Kumar

    2013-01-01

    The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The aim of this study was to develop a simple biological method for the synthesis of silver and gold nanoparticles using Chrysopogon zizanioides. To exploit various plant materials for the biosynthesis of nanoparticles was considered a green technology. An aqueous leaf extract of C. zizanioides was used to synthesize silver and gold nanoparticles by the bioreduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) respectively. Water-soluble organics present in the plant materials were mainly responsible for reducing silver or gold ions to nanosized Ag or Au particles. The synthesized silver and gold nanoparticles were characterized by ultraviolet (UV)-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. The kinetics decline reactions of aqueous silver/gold ion with the C. zizanioides crude extract were determined by UV-visible spectroscopy. SEM analysis showed that aqueous gold ions, when exposed to the extract were reduced and resulted in the biosynthesis of gold nanoparticles in the size range 20–50 nm. This eco-friendly approach for the synthesis of nanoparticles is simple, can be scaled up for large-scale production with powerful bioactivity as demonstrated by the synthesized silver nanoparticles. The synthesized nanoparticles can have clinical use as antibacterial, antioxidant, as well as cytotoxic agents and can be used for biomedical applications. PMID:23861583

  10. Morphological and Proteomic Responses of Eruca sativa Exposed to Silver Nanoparticles or Silver Nitrate

    PubMed Central

    Vannini, Candida; Domingo, Guido; Onelli, Elisabetta; Prinsi, Bhakti; Marsoni, Milena; Espen, Luca; Bracale, Marcella

    2013-01-01

    Silver nanoparticles (AgNPs) are widely used in commercial products, and there are growing concerns about their impact on the environment. Information about the molecular interaction of AgNPs with plants is lacking. To increase our understanding of the mechanisms involved in plant responses to AgNPs and to differentiate between particle specific and ionic silver effects we determined the morphological and proteomic changes induced in Eruca sativa (commonly called rocket) in response to AgNPs or AgNO3. Seedlings were treated for 5 days with different concentrations of AgNPs or AgNO3. A similar increase in root elongation was observed when seedlings were exposed to 10 mg Ag L1 of either PVP-AgNPs or AgNO3. At this concentration we performed electron microscopy investigations and 2-dimensional electrophoresis (2DE) proteomic profiling. The low level of overlap of differentially expressed proteins indicates that AgNPs and AgNO3 cause different plant responses. Both Ag treatments cause changes in proteins involved in the redox regulation and in the sulfur metabolism. These responses could play an important role to maintain cellular homeostasis. Only the AgNP exposure cause the alteration of some proteins related to the endoplasmic reticulum and vacuole indicating these two organelles as targets of the AgNPs action. These data add further evidences that the effects of AgNPs are not simply due to the release of Ag ions. PMID:23874747

  11. Green synthesis of silver nanoparticles using Alternanthera dentata leaf extract at room temperature and their antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Kumar, Deenadayalan Ashok; Palanichamy, V.; Roopan, Selvaraj Mohana

    2014-06-01

    A green rapid biogenic synthesis of silver nanoparticles AgNPs using Alternanthera dentata (A. dentata) aqueous extract was demonstrated in this present study. The formation of silver nanoparticles was confirmed by Surface Plasmon Resonance (SPR) at 430 nm using UV-visible spectrophotometer. The reduction of silver ions to silver nanoparticles by A. dentata extract was completed within 10 min. Synthesized nanoparticles were characterized using UV-visible spectroscopy; Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (TEM). The extracellular silver nanoparticles synthesis by aqueous leaf extract demonstrates rapid, simple and inexpensive method comparable to chemical and microbial methods. The colloidal solution of silver nanoparticles were found to exhibit antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia and, Enterococcus faecalis.

  12. Silver-cotton nanocomposite via in-situ synthesis of silver nanoparticles in self-controlling microfibrillar reactor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silver nanoparticles (Ag NPs) are effective antimicrobial agents, but their application on the surface of a fiber renders them ineffective because Ag NPs are washable. In this study, a stable, non-leaching Ag-cotton nanocomposite was produced by the in-situ formation of Ag NPs in the microfibrillar ...

  13. Transformation of Four Silver/Silver Chloride Nanoparticles during Anaerobic Treatment of Wastewater and Post-processing of Sewage Sludge

    EPA Science Inventory

    The increasing use of silver (Ag) nanoparticles [containing either elemental Ag (Ag-NPs) or AgCl (AgCl-NPs)] in commercial products such as textiles will most likely result in these materials reaching wastewater treatment plants. Previous studies indicate that a conversion of Ag-...

  14. Synthesis of monodispersed silver nanoparticles using Hibiscus cannabinus leaf extract and its antimicrobial activity.

    PubMed

    Bindhu, M R; Umadevi, M

    2013-01-15

    Synthesis of silver nanoparticles using leaf extract of Hibiscus cannabinus has been investigated. The influences of different concentration of H. cannabinus leaf extract, different metal ion concentration and different reaction time on the above cases on the synthesis of nanoparticles were evaluated. The synthesized nanoparticles were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). The prepared silver nanoparticles were monodispersed, spherical in shape with the average particle size of 9 nm and shows surface plasmon peak at 446 nm. The study also reveals that the ascorbic acid present in H. cannabinus leaf extract has been used as reducing agent. The prepared silver nanoparticle shows good antimicrobial activity against Escherichia coli, Proteus mirabilis and Shigella flexneri. PMID:23103459

  15. Environmental Feedbacks and Engineered Nanoparticles: Mitigation of Silver Nanoparticle Toxicity to Chlamydomonas reinhardtii by Algal-Produced Organic Compounds

    PubMed Central

    Stevenson, Louise M.; Dickson, Helen; Klanjscek, Tin; Keller, Arturo A.; McCauley, Edward; Nisbet, Roger M.

    2013-01-01

    The vast majority of nanotoxicity studies measures the effect of exposure to a toxicant on an organism and ignores the potentially important effects of the organism on the toxicant. We investigated the effect of citrate-coated silver nanoparticles (AgNPs) on populations of the freshwater alga Chlamydomonas reinhardtii at different phases of batch culture growth and show that the AgNPs are most toxic to cultures in the early phases of growth. We offer strong evidence that reduced toxicity occurs because extracellular dissolved organic carbon (DOC) compounds produced by the algal cells themselves mitigate the toxicity of AgNPs. We analyzed this feedback with a dynamic model incorporating algal growth, nanoparticle dissolution, bioaccumulation of silver, DOC production and DOC-mediated inactivation of nanoparticles and ionic silver. Our findings demonstrate how the feedback between aquatic organisms and their environment may impact the toxicity and ecological effects of engineered nanoparticles. PMID:24086348

  16. Aggregation Kinetics of Citrate and Polyvinylpyrrolidone Coated Silver Nanoparticles in Monovalent and Divalent Electrolyte Solutions

    PubMed Central

    Huynh, Khanh An; Chen, Kai Loon

    2011-01-01

    The aggregation kinetics of silver nanoparticles (AgNPs) that were coated with two commonly used capping agents—citrate and polyvinylpyrrolidone (PVP)—were investigated. Time-resolved dynamic light scattering (DLS) was employed to measure the aggregation kinetics of the AgNPs over a range of monovalent and divalent electrolyte concentrations. The aggregation behavior of citrate-coated AgNPs in NaCl was in excellent agreement with the predictions based on Derjaguin–Landau–Verwey–Overbeek (DLVO) theory, and the Hamaker constant of citrate-coated AgNPs in aqueous solutions was derived to be 3.7 × 10-20 J. Divalent electrolytes were more efficient in destabilizing the citrate-coated AgNPs, as indicated by the considerably lower critical coagulation concentrations (2.1 mM CaCl2 and 2.7 mM MgCl2 vs. 47.6 mM NaCl). The PVP-coated AgNPs were significantly more stable than citrate-coated AgNPs in both NaCl and CaCl2, which is likely due to steric repulsion imparted by the large, non-charged polymers. The addition of humic acid resulted in the adsorption of the macromolecules on both citrate- and PVP-coated AgNPs. The adsorption of humic acid induced additional electrosteric repulsion that elevated the stability of both nanoparticles in suspensions containing NaCl or low concentrations of CaCl2. Conversely, enhanced aggregation occurred for both nanoparticles at high CaCl2 concentrations due to interparticle bridging by humic acid clusters. PMID:21630686

  17. Silver nanoparticle-based chemiluminescent sensor array for pesticide discrimination.

    PubMed

    He, Yi; Xu, Bo; Li, Wenhao; Yu, Haili

    2015-03-25

    In this work, we developed a simple, facile, and highly sensitive nanoparticle-based chemiluminescent (CL) sensor array for the discrimination of organophosphate and carbamate pesticides. This CL sensor array is based on simultaneous utilization of the triple-channel properties of the luminol-functionalized silver nanoparticle (Lum-AgNP) and H2O2 CL system containing CL intensity, the time for CL emissions to appear, and the time to reach the CL peak value, which are able to be measured via a single experiment. The triple-channel properties can be simultaneously altered after interaction with pesticides, producing distinct CL response patterns as "fingerprints" related to each specific pesticide, which was subjected to principal component analysis (PCA) to generate a clustering map. Using this sensor array, five organophosphate and carbamate pesticides, including dimethoate, dipterex, carbaryl, chlorpyrifos, and carbofuran, have been well-distinguished at a concentration of 24 ?g/mL. A total of 20 unknown pesticide samples have been successfully identified with an accuracy of 95%. The simple strategy of this study is expected to promote the development of functionalized nanomaterial-based sensor arrays. PMID:25751408

  18. Secondary metabolite isolated from Ramalina dumeticola and its application for silver nanoparticles production

    NASA Astrophysics Data System (ADS)

    Mie, Ropisah; Din, Laily B.; Samsudin, Mohd Wahid; Ahmad, Azizan

    2014-09-01

    The aim of the study is to elucidate chemical compositions of the lichen Ramalina dumeticola and to evaluate the ability of the extract to produce silver nanoparticles. The sample was soaked in different polarities of solvent namely hexane, acetone, methanol and water. Isolation work on the acetone extract gave a despite which was identified as sekikaic acid (1). The structure was elucidated by spectroscopic methods. For the production of silver nanoparticles (AgNPs), metabolites from the acetone extract and water extract show potential as reducing agents for silver ions.

  19. Ammonia sensing properties of tapered plastic optical fiber coated with silver nanoparticles/PVP/PVA hybrid

    NASA Astrophysics Data System (ADS)

    Rithesh Raj, D.; Prasanth, S.; Vineeshkumar, T. V.; Sudarsanakumar, C.

    2015-04-01

    A tapered plastic optical fiber gas sensor coated with silver nanoparticles/PVP/PVA hybrid is proposed for ammonia gas sensing application. The spectral characteristics of the gas sensor for different silver concentrations were studied at room temperature against various concentrations (0-500 ppm) of ammonia, methanol and ethanol. All the samples exhibited a linear decrease in spectral intensity with the increase in concentration of ammonia whereas it showed little effect for methanol and ethanol. Gas sensitivity studies revealed that the sensors exhibit higher sensitivity at higher concentrations of silver nanoparticles than at lower concentrations. The spectral characteristics of the sensor selectively represented its ammonia sensitivity.

  20. Antibiofilm properties of chemically synthesized silver nanoparticles found against Pseudomonas aeruginosa

    PubMed Central

    2014-01-01

    Nanomedicine is now being introduced as a recent trend in the field of medicine. It has been documented that metal nanoparticles have antimicrobial effects for bacteria, fungi and viruses. Recent advances in technology has revived the use of silver nanoparticles in the medical field; treatment, diagnosis, monitoring and control of disease. It has been used since ancient times for treating wide range of illnesses. Bacterial cells adheres to surfaces and develop structures known as biofilms. These structures are natural survival strategy of the bacteria to invade the host. They are more tolerant to commonly used antimicrobial agents, thus being more difficult to be controlled. This leads to increase in severity of infection. In this study, we have investigated the effect of silver nanoparticles in the formation of biofilm in multidrug resistant strains of Pseudomonas aeruginosa. Observation showed that biofilm formation occurred at bacterial concentration of 106 cfu/ml for the sensitive strain of P. aeruginosa while in the resistant strain, the biofilm was evident at bacterial concentration of about 103 cfu/ml. The biofilm were then tested against various concentrations of silver nanoparticles to determine the inhibitory effect of the silver nanoparticles. In the sensitive strain, 20 ?g/ml of silver nanoparticles inhibited the growth optimally at bacterial concentration of 104 cfu/ml with an inhibition rate of 67%. Similarly, silver nanoparticles inhibited the formation of biofilm in the resistant strain at an optimal bacterial concentration of 105 cfu/ml with an inhibition rate of 56%. Thus, silver nanoparticles could be used as a potential alternative therapy to reduce severity of disease due to P. aeruginosa infections. PMID:24422704

  1. Novel method for synthesis of silver nanoparticles and their application on wool

    NASA Astrophysics Data System (ADS)

    Boroumand, Majid Nasiri; Montazer, Majid; Simon, Frank; Liesiene, Jolanta; Šaponjic, Zoran; Dutschk, Victoria

    2015-08-01

    In this study, a new method for the synthesis of silver nanoparticles (AgNPs) suitable to impart antibacterial properties of wool fabric is proposed. AgNPs were synthesized by a biochemical reduction method. An aqueous solution of extracted dye from Pomegranate peel was used as a reducing agent for the synthesis of AgNPs from silver nitrate. The ratio of dye to silver nitrate concentration (RDye/Ag = [Dye]/[AgNO3]) is the influencing factor in the synthesis of silver nanoparticles. The nanoparticles formation was followed by UV/Vis absorption spectroscopy. The size and shape of AgNPs were studied by transmission electron microscopy (TEM). The size distribution and Zetapotential of nanoparticles were evaluated using diffraction light scattering (DLS) measurements. The antibacterial potential of biosynthesized silver nanoparticles against Escherichia coli (E. coli) was examined qualitatively and quantitatively. Kinetic analysis of the bacteria reduction using AgNPs synthesized in different way was performed. AgNPs were applied on wool fabrics by exhaustion. The changes in surface morphology of wool fibers after AgNPs loading were studied using scanning electron microscopy (SEM). The amounts of silver deposited on wool fabrics at different pH and temperature were compared applying energy-dispersive X-ray spectroscopy (EDX). AgNPs loaded fabrics showed excellent antibacterial efficiency even after five washing cycles. To investigate the nature of interaction and bonding between the AgNPs and the wool substrate XPS measurements were performed.

  2. Microwave-assisted incorporation of silver nanoparticles in paper for point-of-use water purification.

    PubMed

    Dankovich, Theresa A

    2014-08-01

    This work reports an environmentally benign method for the in situ preparation of silver nanoparticles (AgNPs) in paper using microwave irradiation. Through thermal evaporation, microwave heating with an excess of glucose relative to the silver ion precursor yields nanoparticles on the surface of cellulose fibers within three minutes. Paper sheets were characterized by electron microscopy, UV-Visible reflectance spectroscopy, and atomic absorption spectroscopy. Antibacterial activity and silver release from the AgNP sheets were assessed for model Escherichia coli and Enterococci faecalis bacteria in deionized water and in suspensions that also contained with various influent solution chemistries, i.e. with natural organic matter, salts, and proteins. The paper sheets containing silver nanoparticles were effective in inactivating the test bacteria as they passed through the paper. PMID:25400935

  3. Catharanthus roseus: a natural source for the synthesis of silver nanoparticles

    PubMed Central

    Mukunthan, KS; Elumalai, EK; Patel, Trupti N; Murty, V Ramachandra

    2011-01-01

    Objective To develop a simple rapid procedure for bioreduction of silver nanoparticles (AgNPs) using aqueous leaves extracts of Catharanthus roseus (C. roseus). Methods Characterization were determined by using UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray and X-ray diffraction. Results SEM showed the formation of silver nanoparticles with an average size of 67 nm to 48 nm. X-ray diffraction analysis showed that the particles were crystalline in nature with face centered cubic geometry. Conclusions C. roseus demonstrates strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag+ to Ag0). This study provides evidence for developing large scale commercial production of value-added products for biomedical/nanotechnology-based industries. PMID:23569773

  4. Extracellular biosynthesis and characterization of silver nanoparticles using Aspergillus flavus NJP08: A mechanism perspective

    NASA Astrophysics Data System (ADS)

    Jain, Navin; Bhargava, Arpit; Majumdar, Sonali; Tarafdar, J. C.; Panwar, Jitendra

    2011-02-01

    The present study demonstrates an eco-friendly and low cost protocol for synthesis of silver nanoparticles using the cell-free filtrate of Aspergillus flavus NJP08 when supplied with aqueous silver (Ag+) ions. Identification of the fungal isolate was based on nuclear ribosomal DNA internal transcribed spacer (ITS) identities. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) revealed the formation of spherical metallic silver nanoparticles. The average particle size calculated using Dynamic Light Scattering measurements (DLS) was found to be 17 +/- 5.9 nm. UV-Visible and Fourier transform infrared (FTIR) spectroscopy confirmed the presence of extracellular proteins. SDS-PAGE profiles of the extracellular proteins showed the presence of two intense bands of 32 and 35 kDa, responsible for the synthesis and stability of silver nanoparticles, respectively. A probable mechanism behind the biosynthesis is discussed, which leads to the possibility of using the present protocol in future ``nano-factories''.

  5. Green synthesis of silver nanoparticles using Calotropis gigantea and their potential mosquito larvicidal property

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years the utilization of secondary metabolites from plant extract has emerged as a novel technology for the synthesis of nanoparticles. The aim of the present study was to evaluate the effect of plant synthesized silver nanoparticles (Ag NPs) using aqueous leaf extract of Calotropis gigan...

  6. Analysis of Adhesion and Fracture Energy of NanoParticle Silver in Electronics Packaging Applications

    Microsoft Academic Search

    Sung Chul Joo; Daniel F. Baldwin

    2010-01-01

    Nano-particle silver (NPS) conductors are increasingly being investigated for package level electronics applications. Unlike traditional thick film materials and conductive inks, nano-particle conductors often do not incorporate compounds to promote interfacial adhesion such as binders used in thick films and polymer adhesives used in conductive inks as these adhesion promoters can degrade the electrical performance. The NPS is concerned with

  7. Efficient intracellular delivery and improved biocompatibility of colloidal silver nanoparticles towards intracellular SERS immuno-sensing.

    PubMed

    Bhardwaj, Vinay; Srinivasan, Supriya; McGoron, Anthony J

    2015-06-21

    High throughput intracellular delivery strategies, electroporation, passive and TATHA2 facilitated diffusion of colloidal silver nanoparticles (AgNPs) are investigated for cellular toxicity and uptake using state-of-art analytical techniques. The TATHA2 facilitated approach efficiently delivered high payload with no toxicity, pre-requisites for intracellular applications of plasmonic metal nanoparticles (PMNPs) in sensing and therapeutics. PMID:25939798

  8. Mangifera Indica leaf-assisted biosynthesis of well-dispersed silver nanoparticles

    Microsoft Academic Search

    Daizy Philip

    2011-01-01

    The use of various parts of plants for the synthesis of nanoparticles is considered as a green technology as it does not involve any harmful chemicals. The present study reports a facile and rapid biosynthesis of well-dispersed silver nanoparticles. The method developed is environmentally friendly and allows the reduction to be accelerated by changing the temperature and pH of the

  9. Laundering durable antibacterial cotton fabrics grafted with pomegranate-shaped polymer wrapped in silver nanoparticle aggregations

    NASA Astrophysics Data System (ADS)

    Liu, Hanzhou; Lv, Ming; Deng, Bo; Li, Jingye; Yu, Ming; Huang, Qing; Fan, Chunhai

    2014-08-01

    To improve the laundering durability of the silver functionalized antibacterial cotton fabrics, a radiation-induced coincident reduction and graft polymerization is reported herein where a pomegranate-shaped silver nanoparticle aggregations up to 500 nm can be formed due to the coordination forces between amino group and silver and the wrapping procedure originated from the coincident growth of the silver nanoparticles and polymer graft chains. This pomegranate-shaped silver NPAs functionalized cotton fabric exhibits outstanding antibacterial activities and also excellent laundering durability, where it can inactivate higher than 90% of both E. coli and S. aureus even after 50 accelerated laundering cycles, which is equivalent to 250 commercial or domestic laundering cycles.

  10. A green synthesis method for large area silver thin film containing nanoparticles.

    PubMed

    Shinde, N M; Lokhande, A C; Lokhande, C D

    2014-07-01

    The green synthesis method is inexpensive and convenient for large area deposition of thin films. For the first time, a green synthesis method for large area silver thin film containing nanoparticles is reported. Silver nanostructured films are deposited using silver nitrate solution and guava leaves extract. The study confirmed that the reaction time plays a key role in the growth and shape/size control of silver nanoparticles. The properties of silver films are studied using UV-visible spectrophotometer, scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), contact angle, Fourier-transform Raman (FT-Raman) spectroscopy and Photoluminescence (PL) techniques. Finally, as an application, these films are used effectively in antibacterial activity study. PMID:24836517

  11. Laundering durable antibacterial cotton fabrics grafted with pomegranate-shaped polymer wrapped in silver nanoparticle aggregations

    PubMed Central

    Liu, Hanzhou; Lv, Ming; Deng, Bo; Li, Jingye; Yu, Ming; Huang, Qing; Fan, Chunhai

    2014-01-01

    To improve the laundering durability of the silver functionalized antibacterial cotton fabrics, a radiation-induced coincident reduction and graft polymerization is reported herein where a pomegranate-shaped silver nanoparticle aggregations up to 500?nm can be formed due to the coordination forces between amino group and silver and the wrapping procedure originated from the coincident growth of the silver nanoparticles and polymer graft chains. This pomegranate-shaped silver NPAs functionalized cotton fabric exhibits outstanding antibacterial activities and also excellent laundering durability, where it can inactivate higher than 90% of both E. coli and S. aureus even after 50 accelerated laundering cycles, which is equivalent to 250 commercial or domestic laundering cycles. PMID:25082297

  12. Correlation between defects in capped ZnO nanoparticles and their antibacterial activity.

    PubMed

    Dutta, Raj Kumar; Nenavathu, Bhavani P; Gangishetty, Mahesh K

    2013-09-01

    Antibacterial activity of ZnO nanoparticles (NPs) triggered by generation of reactive oxygen species (ROS) depends on the fate of photoexcited charge carriers. Batches of wide band gap ZnO NPs of 7-9nm sizes, capped with polyethylene glycol (PEG), ascorbic acid (AsA), mercaptoacetic acid (MAA) and polysorbate 80 (T-80) were synthesized by precipitation method. These capped ZnO NPs exhibited ROS induced antibacterial activity, where the ROS was measured by TBARS assay. The PEG capped and AsA capped ZnO NPs exhibited weaker antibacterial activity and were correlated with strong and broad green emission peak owing to oxygen vacancies. The oxygen vacancies were trap sites of photoexcited electrons which inhibited interaction between the photoexcited electrons and oxygen on the surface of the ZnO NPs and accounted for lesser ROS generation and subsequently weaker antibacterial activity. Contrastingly MAA capped and T-80 capped ZnO NPs did not exhibit significant green emission peak, but exhibited 13% and 43% inhibition of growth of E. coli, respectively. The lack of oxygen vacancy defects in MAA capped and T-80 capped ZnO NPs perhaps led to lesser trapping of charge carriers, which is favorable for higher ROS generation and consequently higher antibacterial activity. PMID:23911862

  13. Insights into the cellular response triggered by silver nanoparticles using quantitative proteomics.

    PubMed

    Verano-Braga, Thiago; Miethling-Graff, Rona; Wojdyla, Katarzyna; Rogowska-Wrzesinska, Adelina; Brewer, Jonathan R; Erdmann, Helmut; Kjeldsen, Frank

    2014-03-25

    The use of nanoparticles in foods, materials, and clinical treatments has increased dramatically in the past decade. Because of the possibility of human exposure to nanoparticles, there is an urgent need to investigate the molecular mechanisms underlying the cellular responses that might be triggered. Such information is necessary to assess potential health risks arising from the use of nanoparticles, and for developing new formulations of next generation nanoparticles for clinical treatments. Using mass spectrometry-based proteomic technologies and complementary techniques (e.g., Western blotting and confocal laser scanning microscopy), we present insights into the silver nanoparticle-protein interaction in the human LoVo cell line. Our data indicate that some unique cellular processes are driven by the size. The 100 nm nanoparticles exerted indirect effects via serine/threonine protein kinase (PAK), mitogen-activated protein kinase (MAPK), and phosphatase 2A pathways, and the 20 nm nanoparticles induced direct effects on cellular stress, including generation of reactive oxygen species and protein carbonylation. In addition, we report that proteins involved in SUMOylation were up-regulated after exposure to 20 nm silver nanoparticles. These results were further substantiated by the observation of silver nanoparticles entering the cells; however, data indicate that this was determined by the size of the nanoparticles, since 20 nm particles entered the cells while 100 nm particles did not. PMID:24512182

  14. Synthesis and characterization of cysteine functionalized silver nanoparticles for biomolecule immobilization.

    PubMed

    Upadhyay, Lata Sheo Bachan; Verma, Nishant

    2014-11-01

    A facile method for the aqueous phase synthesis of cysteine-functionalized silver nanoparticles by potato extract has been reported in the present work. These functionalized nanoparticles were then used for the covalent immobilization of a biomolecule, alkaline phosphatase, on its surface through carbodiimide coupling. Different reaction parameters such as cysteine concentration, reducing agent concentration, temperature, pH and reaction time were varied during the nanoparticles' formation, and their effects on plasmon resonance were studied using Ultraviolet-visible spectroscopy. Fourier transform infrared spectroscopy was used to confirm the surface modification of silver nanoparticles by cysteine and the particle size analysis was done using particle size analyzer, which showed the average nanoparticles' size of 61 nm for bare silver nanoparticles and 201 nm for the enzyme-immobilized nanoparticles. The synthesized nanoparticles were found to be highly efficient for the covalent immobilization of alkaline phosphatase on its surface and retained 67% of its initial enzyme activity (9.44 U/mg), with 75% binding efficiency. The shelf life of the enzyme-nanoparticle bioconjugates was found to be 60 days, with a 12% loss in the initial enzyme activity. With a simple synthesis strategy, high immobilization efficiency and enhanced stability, these enzyme-coated nanoparticles have the potential for further integration into the biosensor technology. PMID:24760173

  15. Synthesis and NMR characterization of ligand-capped metal and metal-oxide nanoparticles

    Microsoft Academic Search

    Ramesh Sharma

    2009-01-01

    Ligand-capped metal and metal-oxide nanoparticles (NPs) have some interesting and useful physical properties that are not present in their respective bulk materials. These properties are of research interest in many applications such as catalysis, drug delivery, biological imaging, and plasmonics. In such applications, it is critical to understand the surface structure of NPs and the roles played by the surface

  16. Optical properties of functional composite silver nanoparticles and their potential use in reproductive medicine

    NASA Astrophysics Data System (ADS)

    Syrvatka, Vasyl J.; Slyvchuk, Yurij I.; Rozgoni, Ivan I.; Gevkan, Ivan I.; Bilyy, Oleksandr I.

    2013-06-01

    Silver nanoparticles are promising product of nanotechnology with attractive physicochemical and biological properties. The main aim of the study was to investigate optical properties of functional silver nanoparticles with different composite agents: polyvinylpyrrolidone, bovine serum albumin, hyaluronan and to explore their potential using in reproductive medicine. The date obtained in the study showed that surface modification of nanoparticles leads to change of their optical, physicochemical and biological properties. The optical properties of silver nanoparticles display, that AgNPs with PVP and BSA is most stable in PBS than AgNPs with HA. However the absorption curves after 120 hours of storage show, that AgNPs-HA were the most stable in ethanol. Results show, that silver nanoparticles did not effect on sperm viability and motility, but cause a changes of some biochemical parameters of conditioned medium, particular increase the concentration of triglycerides, activity of alkaline phosphatase, lactate dehydrogenase and decrease the activity of aspartate aminotransferase and alanine aminotransferase after 3 h of in vitro cultivation at 37°C. According to our latest data AgNPs with HA have a less toxic effect on biological processes in rabbits sperm compared with AgNPs with PVP and BSA. Nevertheless all functional composites of silver nanoparticles at the concentration of 0.1 ?g/mL have no toxic effect on spermatozoa and can be successfully applied in reproductive medicine at low concentrations as signal enhancers, optical sensors, and biomarkers.

  17. [Characterization of silver nanoparticles migration from package materials destined for contact with foods].

    PubMed

    Smirnova, V V; Krasnoiarova, O V; Pridvorova, S M; Zherdev, A V; Gmoshinski?, I V; Kazydub, G V; Popov, K I; Khotimchenko, S A

    2012-01-01

    There was studied migration of artificial silver nanoparticles from polyethylene films destined for package of such foods as bread and poultry into model media reproducing physico-chemical properties and composition of said products. Modification of films was performed by 5- or 10-fold spraying of silver nanoparticles on the surface of package material. Model media were composed from water, alcohol and plant oil according to US FDA and Russian Federal Service for Surveillance of Consumer Rights Protection and Human Well-Being official recommendation. Nanoparticles were detected in model media by means of transmission electron and atomic force microscopy. Quantification of silver in nanoparticles migrating from films was performed by mass-spectrometry with inductively coupled plasma. The results obtained showed that silver migrated from films into test media in form of nanoparticles with mean diameter close to 10-20 nm. Migrated particles were partially aggregated to complexes with dimension about 50 nm with degree of aggregation depending on media composition. Quantification showed that amounts of silver nanoparticles migrating in foods did not exceed save level of this nanomaterial consumption even in aggravated conditions when almost all volume of product was consumed in form packaged in films modified with nanosilver. PMID:22774476

  18. Toxicity and accumulation of silver nanoparticles during development of the marine polychaete Platynereis dumerilii.

    PubMed

    García-Alonso, Javier; Rodriguez-Sanchez, Neus; Misra, Superb K; Valsami-Jones, Eugenia; Croteau, Marie-Noële; Luoma, Samuel N; Rainbow, Philip S

    2014-04-01

    Pollutants affecting species at the population level generate ecological instability in natural systems. The success of early life stages, such as those of aquatic invertebrates, is highly affected by adverse environmental conditions. Silver released into the environment from emerging nanotechnology represents such a threat. Sediments are sinks for numerous pollutants, which aggregate and/or associate with depositing suspended particles. Deposit feeder such as the annelid Platynereis dumerilii, which has a large associated literature on its development, is an excellent model organism for exposure studies in coastal environments. We exposed eggs, larvae, juveniles and adults of P. dumerilii to various concentrations of citrate (cit-Ag NPs) or humic acid (HA-Ag NPs) capped silver nanoparticles (Ag NPs) as well to dissolved Ag (added as AgNO3). We showed that mortality and abnormal development rate increased with younger life stages. While adults and juvenile were the most tolerant life stages, fertilized eggs were highly sensitive to AgNO3, cit-Ag NPs and HA-Ag NPs. Exposures to HA-Ag NPs triggered the highest cute toxicity responses in P. dumerilii and in most cases both Ag NPs were more toxic than AgNO3. Uptake rate of HA-Ag NPs in adult worms was also higher than from other Ag forms, consistent with toxicity to other life stages. The early stages of the life cycle of marine coastal organisms are more affected by Ag NPs than the juvenile or adult life stages, indicating that exposure experiments at the larval level contribute to realistic eco-toxicological studies in aquatic environments. PMID:24514586

  19. Biosynthesis of silver nanoparticles using Acacia leucophloea extract and their antibacterial activity

    PubMed Central

    Murugan, Kasi; Senthilkumar, Balakrishnan; Senbagam, Duraisamy; Al-Sohaibani, Saleh

    2014-01-01

    The immense potential of nanobiotechnology makes it an intensely researched field in modern medicine. Green nanomaterial synthesis techniques for medicinal applications are desired because of their biocompatibility and lack of toxic byproducts. We report the toxic byproducts free phytosynthesis of stable silver nanoparticles (AgNPs) using the bark extract of the traditional medicinal plant Acacia leucophloea (Fabaceae). Visual observation, ultraviolet–visible spectroscopy, and transmission electron microscopy (TEM) were used to characterize the synthesized AgNPs. The visible yellow-brown color formation and surface plasmon resonance at 440 nm indicates the biosynthesis of AgNP. The TEM images show polydisperse, mostly spherical AgNP particles of 17–29 nm. Fourier transform infrared spectroscopy revealed that primary amines, aldehyde/ketone, aromatic, azo, and nitro compounds of the A. leucophloea extract may participate in the bioreduction and capping of the formed AgNPs. X-ray diffraction confirmed the crystallinity of the AgNPs. The in vitro agar well diffusion method confirmed the potential antibacterial activity of the plant extract and synthesized AgNPs against the common bacterial pathogens Staphylococcus aureus (MTCC 737), Bacillus cereus (MTCC 1272), Listeria monocytogenes (MTCC 657), and Shigella flexneri (MTCC 1475). This research combines the inherent antimicrobial activity of silver metals with the A. leucophloea extract, yielding antibacterial activity-enhanced AgNPs. This new biomimetic approach using traditional medicinal plant (A. leucophloea) barks to synthesize biocompatible antibacterial AgNPs could easily be scaled up for additional biomedical applications. These polydisperse AgNPs green-synthesized via A. leucophloea bark extract can readily be used in many applications not requiring high uniformity in particle size or shape. PMID:24876776

  20. Toxicity and accumulation of silver nanoparticles during development of the marine polychaete Platynereis dumerilii

    USGS Publications Warehouse

    García-Alonso, Javier; Rodriguez-Sanchez, Neus; Misra, Superb K.; Valsami-Jones, Eugenia; Croteau, Marie-Noële; Luoma, Samuel N.; Rainbow, Philip S.

    2014-01-01

    Pollutants affecting species at the population level generate ecological instability in natural systems. The success of early life stages, such as those of aquatic invertebrates, is highly affected by adverse environmental conditions. Silver released into the environment from emerging nanotechnology represents such a threat. Sediments are sinks for numerous pollutants, which aggregate and/or associate with depositing suspended particles. Deposit feeder such as the annelid Platynereis dumerilii, which has a large associated literature on its development, is an excellent model organism for exposure studies in coastal environments. We exposed eggs, larvae, juveniles and adults of P. dumerilii to various concentrations of citrate (cit-Ag NPs) or humic acid (HA-Ag NPs) capped silver nanoparticles (Ag NPs) as well to dissolved Ag (added as AgNO3). We showed that mortality and abnormal development rate increased with younger life stages. While adults and juvenile were the most tolerant life stages, fertilized eggs were highly sensitive to AgNO3, cit-Ag NPs and HA-Ag NPs. Exposures to HA-Ag NPs triggered the highest cute toxicity responses in P. dumerilii and in most cases both Ag NPs were more toxic than AgNO3. Uptake rate of HA-Ag NPs in adult worms was also higher than from other Ag forms, consistent with toxicity to other life stages. The early stages of the life cycle of marine coastal organisms are more affected by Ag NPs than the juvenile or adult life stages, indicating that exposure experiments at the larval level contribute to realistic eco-toxicological studies in aquatic environments.

  1. Synthesis of Nanocomposites of Polyvinyl Alcohol with Silver Nanoparticles and Their Use

    NASA Astrophysics Data System (ADS)

    Bhat, N. V.; Karmakar, N. S.; Kothari, D. C.

    2013-08-01

    Composites of polyvinyl alcohol (PVA) containing silver nanoparticles were prepared using in situ synthesis of nanoparticles. Structure and properties of these composites were investigated using UV-Vis spectroscopy, XRD, DSC, SEM and AFM. The studies show that PVA can reduce the AgNO3 to yield silver nanoparticles and in the process forms bonds with PVA chains. The anti-bacterial properties of these films were studied by qualitative as well as quantitative methods which gave the values of 98% for gram positive and 89% for gram negative bacteria.

  2. Investigation into the molar feeding ratio and temperature dependence on the replacement reaction between platinum ions and silver nanoparticles

    E-print Network

    Stuk, Archimedes

    2010-01-01

    The deliberate structuring of bimetallic nanoparticles has useful applications in both fuel cell applications and biomedical research. This thesis studies the replacement reaction between platinum ions and silver nanoparticles, ...

  3. Formation of CdS nanoparticles using starch as capping agent

    NASA Astrophysics Data System (ADS)

    Rodríguez, P.; Muñoz-Aguirre, N.; Martínez, E. San-Martin; Gonzalez, G.; Zelaya, O.; Mendoza, J.

    2008-11-01

    CdS nanoparticles have been synthesized using starch as capping agent in aqueous solution. The morphology and crystalline structure of such samples were measured by high-resolution transmission electron microscopy and X-ray diffraction, respectively. The average grain size of the nanoparticles determined by these techniques was of the order of 5 nm. Photoluminescence of CdS nanoparticles shows a strong emission peak below to the band gap bulk semiconductor attributed to center trap states, also the broadening peak was interpreted in terms of electron-phonon interaction.

  4. Solution-processable organic-capped titanium oxide nanoparticle dielectrics for organic thin-film transistors

    Microsoft Academic Search

    Qin Jia Cai; Ye Gan; Mary B. Chan-Park; Hong Bin Yang; Zhi Song Lu; Qun Liang Song; Chang Ming Li; Zhi Li Dong

    2008-01-01

    Oleic acid-capped titanium dioxide (OA-TiO2) nanoparticles were solution-processed to form homogeneous dielectrics for organic thin-film transistors (TFTs) of top-gate and bottom-gate configurations. The OA-TiO2 nanoparticles were well-dispersed into the organic solvent and spin-coated to give homogeneous films. These nanoparticle films showed a dielectric constant of about 5.3 and low leakage current density of ~3×10-8 A\\/cm2 under an electric field of

  5. Solution-processable organic-capped titanium oxide nanoparticle dielectrics for organic thin-film transistors

    Microsoft Academic Search

    Qin Jia Cai; Ye Gan; Mary B. Chan-Park; Hong Bin Yang; Zhi Song Lu; Qun Liang Song; Chang Ming Li; Zhi Li Dong

    2008-01-01

    Oleic acid-capped titanium dioxide (OA-TiO2) nanoparticles were solution-processed to form homogeneous dielectrics for organic thin-film transistors (TFTs) of top-gate and bottom-gate configurations. The OA-TiO2 nanoparticles were well-dispersed into the organic solvent and spin-coated to give homogeneous films. These nanoparticle films showed a dielectric constant of about 5.3 and low leakage current density of ?3×10?8 A\\/cm2 under an electric field of

  6. Uptake and effects of manufactured silver nanoparticles in rainbow trout (Oncorhynchus mykiss) gill cells.

    PubMed

    Farkas, Julia; Christian, Paul; Gallego-Urrea, Julián Alberto; Roos, Norbert; Hassellöv, Martin; Tollefsen, Knut Erik; Thomas, Kevin V

    2011-01-17

    Nanoparticles are already widely used in technology, medicine and consumer products, but there are limited data on their effects on the aquatic environment. In this study the uptake and effect of citrate (AgNP(CIT)) and polyvinylpyrrolidone (AgNP(PVP)) coated manufactured silver nanoparticles, as well as AgNO(3) (Ag(+)) were tested using primary gill cells of rainbow trout (Oncorhynchus mykiss). Prior to use, the nanoparticles were characterized for size, surface charge and aggregation behavior. Gill cells were cultured either as monolayers on solid support, or as multilayers on a permeable support cell culturing system, enabling transport studies. The uptake of silver nanoparticles and Ag(+) after exposure to 10 mg L(-1) was determined with microscopical methods and inductively coupled plasma mass spectrometry (ICP-MS). Cytotoxicity, in terms of membrane integrity, as well as oxidative stress (depletion of reduced glutathione) was tested at silver concentrations ranging from 0.1 mg L(-1) to 10 mg L(-1). Results show that AgNP(CIT) nanoparticles are readily taken up into gill cell monolayers while uptake was less for AgNP(PVP). In contrast, it appears that the slightly smaller AgNP(PVP) were transported through cultured multilayers to a higher extent, with transport rates generally being in the ng cm(-2) range for 48 h exposures. Transport rates for all exposures were dependent on the epithelial tightness. Moderate cytotoxic effects were seen for all silver treatments. Levels of reduced glutathione were elevated in contrast to control groups, pointing on a possible overcompensation reaction. Taken together silver nanoparticles were taken up into cells and did cause silver transport over cultured epithelial layers with uptake and transport rates being different for the two nanoparticle species. All silver treatments had measurable effects on cell viability. PMID:20952077

  7. Preparation of silver nanoparticles in virgin coconut oil using laser ablation

    PubMed Central

    Zamiri, Reza; Azmi, B Z; Sadrolhosseini, Amir Reza; Ahangar, Hossein Abbastabar; Zaidan, A W; Mahdi, M A

    2011-01-01

    Laser ablation of a silver plate immersed in virgin coconut oil was carried out for fabrication of silver nanoparticles. A Nd:YAG laser at wavelengths of 1064 nm was used for ablation of the plate at different times. The virgin coconut oil allowed formation of nanoparticles with well-dispersed, uniform particle diameters that were stable for a reasonable length of time. The particle sizes and volume fraction of nanoparticles inside the solutions obtained at 15, 30, 45 min ablation times were 4.84, 5.18, 6.33 nm and 1.0 × 10?8, 1.6 × 10?8, 2.4 × 10?8, respectively. The presented method for preparation of silver nanoparticles in virgin coconut oil is environmentally friendly and may be considered a green method. PMID:21289983

  8. Preparation of silver nanoparticles in virgin coconut oil using laser ablation.

    PubMed

    Zamiri, Reza; Azmi, B Z; Sadrolhosseini, Amir Reza; Ahangar, Hossein Abbastabar; Zaidan, A W; Mahdi, M A

    2011-01-01

    Laser ablation of a silver plate immersed in virgin coconut oil was carried out for fabrication of silver nanoparticles. A Nd:YAG laser at wavelengths of 1064 nm was used for ablation of the plate at different times. The virgin coconut oil allowed formation of nanoparticles with well-dispersed, uniform particle diameters that were stable for a reasonable length of time. The particle sizes and volume fraction of nanoparticles inside the solutions obtained at 15, 30, 45 min ablation times were 4.84, 5.18, 6.33 nm and 1.0 × 10(-8), 1.6 × 10(-8), 2.4 × 10(-8), respectively. The presented method for preparation of silver nanoparticles in virgin coconut oil is environmentally friendly and may be considered a green method. PMID:21289983

  9. In situ growth of silver nanoparticles on TEMPO-oxidized jute fibers by microwave heating.

    PubMed

    Cao, Xinwang; Ding, Bin; Yu, Jianyong; Al-Deyab, Salem S

    2013-01-30

    Cellulose fibers deposited with metallic nanoparticles as one kind of renewable, biocompatible and antimicrobial nanomaterials evoke much interest because of their versatility in various applications. Herein, for the first time, a facile, simple and rapid method was developed to fabricate TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) selectively oxidized jute fibers in situ deposited with silver nanoparticles in the absence of reducing reagents. The average size of silver nanoparticles deposited on the fibers is 50.0 ± 2.0 nm by microwave heating for 5 min and 90.0 ± 4.7 nm for 10 min heating sample, respectively. The versatile jute-silver nanoparticles nanocomposites with superior thermal stability and high crystallinity would be particularly useful for applications in the public health care and biomedical fields. PMID:23218337

  10. Antibacterial and cytotoxic effect of biologically synthesized silver nanoparticles using aqueous root extract of Erythrina indica lam

    NASA Astrophysics Data System (ADS)

    Rathi Sre, P. R.; Reka, M.; Poovazhagi, R.; Arul Kumar, M.; Murugesan, K.

    2015-01-01

    Simple, yet an effective and rapid approach for the green synthesis of silver nanoparticles (Ag NPs) using root extract of Erythrina indica and its in vitro antibacterial activity was tried against human pathogenic bacteria and its cytotoxic effect in breast and lung cancer cell lines has been demonstrated in this study. Various instrumental techniques were adopted to characterize the synthesized Ag NPs viz. UV-Vis (Ultra violet), FTIR (Fourier Transform Infrared), XRD (X-ray diffraction), DLS (Dynamic light scattering), HR TEM (High-resolution transmission electron microscopy), EDX (Energy-dispersive X-ray spectroscopy). Surface plasmon spectra for Ag NPs are centered nearly at 438 nm with dark brown color. FTIR analysis revealed the presence of terpenes, phenol, flavonols and tannin act as effective reducing and capping agents for converting silver nitrate to Ag NPs. The synthesized Ag NPs were found to be spherical in shape with size in the range of 20-118 nm. Moreover, the synthesized Ag NPs showed potent antibacterial activity against Gram positive and Gram negative bacteria and these biologically synthesized nanoparticles were also proved to exhibit excellent cytotoxic effect on breast and lung cancer cell lines.

  11. Antibacterial and cytotoxic effect of biologically synthesized silver nanoparticles using aqueous root extract of Erythrina indica lam.

    PubMed

    Rathi Sre, P R; Reka, M; Poovazhagi, R; Arul Kumar, M; Murugesan, K

    2015-01-25

    Simple, yet an effective and rapid approach for the green synthesis of silver nanoparticles (Ag NPs) using root extract of Erythrina indica and its in vitro antibacterial activity was tried against human pathogenic bacteria and its cytotoxic effect in breast and lung cancer cell lines has been demonstrated in this study. Various instrumental techniques were adopted to characterize the synthesized Ag NPs viz. UV-Vis (Ultra violet), FTIR (Fourier Transform Infrared), XRD (X-ray diffraction), DLS (Dynamic light scattering), HR TEM (High-resolution transmission electron microscopy), EDX (Energy-dispersive X-ray spectroscopy). Surface plasmon spectra for Ag NPs are centered nearly at 438 nm with dark brown color. FTIR analysis revealed the presence of terpenes, phenol, flavonols and tannin act as effective reducing and capping agents for converting silver nitrate to Ag NPs. The synthesized Ag NPs were found to be spherical in shape with size in the range of 20-118 nm. Moreover, the synthesized Ag NPs showed potent antibacterial activity against Gram positive and Gram negative bacteria and these biologically synthesized nanoparticles were also proved to exhibit excellent cytotoxic effect on breast and lung cancer cell lines. PMID:25189525

  12. Prolonged reorganization of thiol-capped Au nanoparticles layered structures

    NASA Astrophysics Data System (ADS)

    Kundu, Sarathi; Das, Kaushik; Konovalov, Oleg

    2013-09-01

    Prolonged reorganization behaviour of mono-, di-, tri- and multi-layer films of Au nanoparticles prepared by Langmuir-Blodgett method on hydrophobic Si(001) substrates have been studied by using X-ray scattering techniques. Out-of-plane study shows that although at the initial stage the reorganization occurs through the compaction of the films keeping the layered structure unchanged but finally all layered structures modify to monolayer structure. Due to this reorganization the Au density increases within the nanometer thick films. In-plane study shows that inside the reorganized films Au nanoparticles are distributed randomly and the particle size modifies as the metallic core of Au nanoparticles coalesces.

  13. Antimicrobial and antioxidant activities of Mimusops elengi seed extract mediated isotropic silver nanoparticles.

    PubMed

    Kiran Kumar, Hoskote Anand; Mandal, Badal Kumar; Mohan Kumar, Kesarla; Maddinedi, Sireesh babu; Sai Kumar, Tammina; Madhiyazhagan, Pavithra; Ghosh, Asit Ranjan

    2014-09-15

    The present study reports the use of Mimusops elengi (M. elengi) fruit extract for the synthesis of silver nanoparticles (Ag NPs). The synthesized Ag NPs was initially noticed through visual color change from yellow to reddish brown and further confirmed by surface plasmonic resonance (SPR) band at 429 nm using UV-Visible spectroscopy. Morphology and size of Ag NPs was determined by Transmission Electron Microscopy (TEM) analysis. X-ray Diffraction (XRD) study revealed crystalline nature of Ag NPs. The prolonged stability of Ag NPs was due to capping of oxidized polyphenols which was established by Fourier Transform Infrared Spectroscopy (FTIR) study. The polyphenols present in M. elengi fruit extract was analyzed by High Pressure Liquid Chromatography (HPLC) and the results revealed the presence of ascorbic acid, gallic acid, pyrogallol and resorcinol. In order to study the role of these polyphenols in reducing Ag+ ions to Ag NPs, analyses of extracts before reduction and after reduction were carried out. In addition, the synthesized Ag NPs were tested for antibacterial and antioxidant activities against Staphylococcus aureus (S. Aureus) and Escherichia coli (E. coli). Ag NPs showed good antimicrobial activity against both gram positive (S. aureus) and gram negative (E. coli) bacteria. It also showed good antioxidant activity as compared to ascorbic acid as standard antioxidant. PMID:24759779

  14. Effect of stabilizing agent on the morphology and optical properties of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Seoudi, R.; Shabaka, A.; El Sayed, Z. A.; Anis, B.

    2011-11-01

    Silver nanoparticles (AgNPs) were prepared in different sizes and forms by reduction of AgNO 3 using sodium borohydride as a reducing agent and different concentrations of dodecanethiol (DDT) as a stabilizing agent. The morphology and particle size were studied by Transmission Electron Microscopy (TEM) and the results showed that different sizes of AgNPs were formed. The particle size was controlled by changing the ratio between AgNO 3 and (DDT) in the presence of NaBH 4. Appearance of surface Plasmon band in the ultraviolet-visible spectra (420-445 nm) was due to the formation of AgNPs in different sizes. The data of FTIR and X-ray diffraction confirm that the DDT molecules have coordinated to the surface of Nano-Ag particles through their head-groups. AgNPs were synthesized from a large enough concentration of DDT and had a very small grain size. It was supposed that the surface-capped AgNPs prohibits significantly increased stability and dispersibility.

  15. Silver nanoparticles induce endoplasmatic reticulum stress response in zebrafish

    SciTech Connect

    Christen, Verena [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Capelle, Martinus [Crucell, P.O. Box 2048, NL-2301 Leiden (Netherlands); Fent, Karl, E-mail: karl.fent@fhnw.ch [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology Zürich, Department of Environmental Systems Science, CH-8092 Zürich (Switzerland)

    2013-10-15

    Silver nanoparticles (AgNPs) find increasing applications, and therefore humans and the environment are increasingly exposed to them. However, potential toxicological implications are not sufficiently known. Here we investigate effects of AgNPs (average size 120 nm) on zebrafish in vitro and in vivo, and compare them to human hepatoma cells (Huh7). AgNPs are incorporated in zebrafish liver cells (ZFL) and Huh7, and in zebrafish embryos. In ZFL cells AgNPs lead to induction of reactive oxygen species (ROS), endoplasmatic reticulum (ER) stress response, and TNF-?. Transcriptional alterations also occur in pro-apoptotic genes p53 and Bax. The transcriptional profile differed in ZFL and Huh7 cells. In ZFL cells, the ER stress marker BiP is induced, concomitant with the ER stress marker ATF-6 and spliced XBP-1 after 6 h and 24 h exposure to 0.5 g/L and 0.05 g/L AgNPs, respectively. This indicates the induction of different pathways of the ER stress response. Moreover, AgNPs induce TNF-?. In zebrafish embryos exposed to 0.01, 0.1, 1 and 5 mg/L AgNPs hatching was affected and morphological defects occurred at high concentrations. ER stress related gene transcripts BiP and Synv are significantly up-regulated after 24 h at 0.1 and 5 mg/L AgNPs. Furthermore, transcriptional alterations occurred in the pro-apoptotic genes Noxa and p21. The ER stress response was strong in ZFL cells and occurred in zebrafish embryos as well. Our data demonstrate for the first time that AgNPs lead to induction of ER stress in zebrafish. The induction of ER stress can have several consequences including the activation of apoptotic and inflammatory pathways. - Highlights: • Effects of silver nanoparticles (120 nm AgNPs) are investigated in zebrafish. • AgNPs induce all ER stress reponses in vitro in zebrafish liver cells. • AgNPs induce weak ER stress in zebrafish embryos. • AgNPs induce oxidative stress and transcripts of pro-apoptosis genes.

  16. Laser-induced growth and reformation of gold and silver nanoparticles

    Microsoft Academic Search

    Seol Ji Kim; Chil Seong Ah; Du-Jeon Jang

    2009-01-01

    The sizes, shapes, and growth rates of gold and silver nanoparticles stabilized with polyvinylpyrrolidone in water can be\\u000a controlled by using picosecond laser pulses. The nucleation of small metal clusters formed with NaBH4 addition to produce nanoparticles takes two months with aging but 30 min with laser irradiation. Laser pulses can also induce\\u000a nanoparticles to have narrow size and shape distribution

  17. Differential effects and potential adverse outcomes of ionic silver and silver nanoparticles in vivo and in vitro.

    PubMed

    Garcia-Reyero, Natàlia; Kennedy, Alan J; Escalon, B Lynn; Habib, Tanwir; Laird, Jennifer G; Rawat, Arun; Wiseman, Steven; Hecker, Markus; Denslow, Nancy; Steevens, Jeffery A; Perkins, Edward J

    2014-04-15

    Nanoparticles are of concern because of widespread use, but it is unclear if metal nanoparticles cause effects directly or indirectly. We explored whether polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) cause effects through intact nanoparticles or dissolved silver. Females of the model species fathead minnow (Pimephales promelas) were exposed to either 4.8 ?g/L of AgNO3 or 61.4 ?g/L of PVP-AgNPs for 96h. Microarray analyses were used to identify impacted receptors and toxicity pathways in liver and brain tissues that were confirmed using in vitro mammalian assays. AgNO3 and PVP-AgNP exposed fish had common and distinct effects consistent with both intact nanoparticles and dissolved silver causing effects. PVP-AgNPs and AgNO3 both affected pathways involved in Na(+), K(+), and H(+) homeostasis and oxidative stress but different neurotoxicity pathways. In vivo effects were supported by PVP-AgNP activation of five in vitro nuclear receptor assays and inhibition of ligand binding to the dopamine receptor. AgNO3 inhibited ligand binding to adrenergic receptors ?1 and ?2 and cannabinoid receptor CB1, but had no effect in nuclear receptor assays. PVP-AgNPs have the potential to cause effects both through intact nanoparticles and metal ions, each interacting with different initiating events. Since the in vitro and in vivo assays examined here are commonly used in human and ecological hazard screening, this work suggests that environmental health assessments should consider effects of intact nanoparticles in addition to dissolved metals. PMID:24684273

  18. Synthesis of water-dispersible silver nanoparticles by thermal decomposition of water-soluble silver oxalate precursors.

    PubMed

    Togashi, Takanari; Saito, Kota; Matsuda, Yukiko; Sato, Ibuki; Kon, Hiroki; Uruma, Keirei; Ishizaki, Manabu; Kanaizuka, Katsuhiko; Sakamoto, Masatomi; Ohya, Norimasa; Kurihara, Masato

    2014-08-01

    Silver oxalate, one of the coordination polymer crystals, is a promising synthetic precursor for transformation into Ag nanoparticles without any reducing chemicals via thermal decomposition of the oxalate ions. However, its insoluble nature in solvents has been a great disadvantage, especially for systematic control of crystal growth of the Ag nanoparticles, while such control of inorganic nanoparticles has been generally performed using soluble precursors in homogeneous solutions. In this paper, we document our discovery of water-soluble species from the reaction between the insoluble silver oxalate and N,N-dimethyl-1,3-diaminopropane. The water-soluble species underwent low-temperature thermal decomposition of the oxalate ions at 30 °C with evolution of CO2 to reduce Ag+ to Ag0. Water-dispersible Ag nanoparticles have been successfully synthesized from the water-soluble species in the presence of gelatin via similar thermal decomposition at 100 °C. The gelatin-protected and water-dispersible Ag nanoparticles with a mean diameter of 25.1 nm appeared. In addition, antibacterial activity of the prepared water-dispersible Ag nanoparticles has been preliminarily investigated. PMID:25936049

  19. Wet chemical synthesis of gold nanoparticles using silver seeds: a shape control from nanorods to hollow spherical nanoparticles

    Microsoft Academic Search

    Zhi-Chuan Xu; Cheng-Min Shen; Cong-Wen Xiao; Tian-Zhong Yang; Huai-Ruo Zhang; Jian-Qi Li; Hu-Lin Li; Hong-Jun Gao

    2007-01-01

    A seed-mediated method was employed here for CTAB-assisted gold nanoparticle growth. 3-4 nm silver aqueous colloid was stabilized by sodium citrate and used as seed solution to initial gold particle growth. The concentration of seed solution was calculated based on its relationship with silver atom concentration and seed particle statistical mean volume. It was found that there is a maximum

  20. Stability and aggregation of silver and titanium dioxide nanoparticles in seawater: role of salinity and dissolved organic carbon.

    PubMed

    Wang, Huanhua; Burgess, Robert M; Cantwell, Mark G; Portis, Lisa M; Perron, Monique M; Wu, Fengchang; Ho, Kay T

    2014-05-01

    The behavior and fate of nanoparticles (NPs) in the marine environment are largely unknown and potentially have important environmental and human health implications. The aggregation and fate of NPs in the marine environment are greatly influenced by their interactions with seawater and dissolved organic carbon (DOC). In the present study, the stability and aggregation of 30-nm-diameter silver nanoparticles (AgNPs) capped with citrate and polyvinylpyrrolidone (PVP; AgNP-citrate and AgNP-PVP) and 21-nm-diameter titanium dioxide (TiO(2)) NPs as affected by seawater salinity and DOC were investigated by measuring hydrodynamic diameters and zeta potentials. The added DOC (in humic acid form) stabilized the 3 types of NPs when the seawater salinities were ?5 parts per thousand (ppt), but the stabilizing effect of DOC was reduced by a higher salinity (e.g., 30 ppt). In addition, AgNP-PVP was more stable than AgNP-citrate in seawater, indicating that surface capping agents and stabilization mechanisms govern the stability and aggregation of NPs. Statistical analysis showed that salinity is the most dominant influence on the stability and aggregation of AgNPs and TiO(2) NPs, followed by DOC. These findings expand our knowledge on the behavior of AgNPs and TiO2 NPs in seawater and indicate that the fate of these NPs will be primarily to aggregate in the water column, precipitate, and accumulate in sediments following release into the marine environment. PMID:24464618

  1. Anionic 11-mercaptoundecanoic acid capped ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Šimšíková, Michaela; Antalík, Marián; Ka?uchová, Mária; Škvarla, Ji?í

    2013-10-01

    The anionic zinc oxide nanoparticles have been prepared at room temperature by a precipitation method using ZnCl2 and NaOH and surface modification with 11-mercaptoundecanoic acid (MUA). Atomic force microscopy (AFM) was used for definition of morphology and size of prepared nanoparticles which was proved by measurements of particle size distribution using Zetasizer. Successful coating with MUA as surfactant was acknowledged by X-ray photoelectron spectroscopy and ATR FT-IR spectroscopy. The isoelectric point (IEP) of ZnO-MUA nanoparticles was obtained by measurements of zeta potential and FT-IR dependence on pH; the obtained value was approximately 3.58. The value of exchanged protons was 2.88 which indicates a positive binding cooperativity of modified nanoparticles.

  2. Immobilized silver nanoparticles enhance contact killing and show highest efficacy: elucidation of the mechanism of bactericidal action of silver

    NASA Astrophysics Data System (ADS)

    Agnihotri, Shekhar; Mukherji, Soumyo; Mukherji, Suparna

    2013-07-01

    Antimicrobial materials with immobilized/entrapped silver nanoparticles (AgNPs) are of considerable interest. There is significant debate on the mode of bactericidal action of AgNPs, and both contact killing and/or ion mediated killing have been proposed. In this study, AgNPs were immobilized on an amine-functionalized silica surface and their bactericidal activity was studied concurrently with the silver release profile over time. This was compared with similar studies performed using colloidal AgNPs and AgCl surfaces that released Ag ions. We conclude that contact killing is the predominant bactericidal mechanism and surface immobilized nanoparticles show greater efficacy than colloidal AgNPs, as well as a higher concentration of silver ions in solution. In addition, the AgNP immobilized substrate was used multiple times with good efficacy, indicating this immobilization protocol is effective for retaining AgNPs while maintaining their disinfection potential. The antibacterial surface was found to be extremely stable in aqueous medium and no significant leaching (~1.15% of total silver deposited) of the AgNPs was observed. Thus, immobilization of AgNPs on a surface may promote reuse, reduce environmental risks associated with leaching of AgNPs and enhance cost effectiveness.Antimicrobial materials with immobilized/entrapped silver nanoparticles (AgNPs) are of considerable interest. There is significant debate on the mode of bactericidal action of AgNPs, and both contact killing and/or ion mediated killing have been proposed. In this study, AgNPs were immobilized on an amine-functionalized silica surface and their bactericidal activity was studied concurrently with the silver release profile over time. This was compared with similar studies performed using colloidal AgNPs and AgCl surfaces that released Ag ions. We conclude that contact killing is the predominant bactericidal mechanism and surface immobilized nanoparticles show greater efficacy than colloidal AgNPs, as well as a higher concentration of silver ions in solution. In addition, the AgNP immobilized substrate was used multiple times with good efficacy, indicating this immobilization protocol is effective for retaining AgNPs while maintaining their disinfection potential. The antibacterial surface was found to be extremely stable in aqueous medium and no significant leaching (~1.15% of total silver deposited) of the AgNPs was observed. Thus, immobilization of AgNPs on a surface may promote reuse, reduce environmental risks associated with leaching of AgNPs and enhance cost effectiveness. Electronic supplementary information (ESI) available: Photographic image of silanization chamber; FEG-TEM image to show particle distribution of as-synthesized silver nanoparticles; photographic image of pristine amino-silanized glass and AgNPs immobilized glass; batch reactor fabrication for disinfection and silver release studies; surface coverage of silver nanoparticle immobilized glass substrate; and EDX analysis of the treated bacterial (E. coli) cells. See DOI: 10.1039/c3nr00024a

  3. Enhancement of antidandruff activity of shampoo by biosynthesized silver nanoparticles from Solanum trilobatum plant leaf

    NASA Astrophysics Data System (ADS)

    Pant, Gaurav; Nayak, Nitesh; Gyana Prasuna, R.

    2013-10-01

    The present investigation describes simple and effective method for synthesis of silver nanoparticles via green route. Solanum trilobatum Linn extract were prepared by both conventional and homogenization method. We optimized the production of silver nanoparticles under sunlight, microwave and room temperature. The best results were obtained with sunlight irradiation, exhibiting 15-20 nm silver nanoparticles having cubic and hexagonal shape. Biosynthesized nanoparticles were highly toxic to various bacterial strains tested. In this study we report antibacterial activity against various Gram negative ( Klebsiella pneumoniae, Vibrio cholerae and Salmonella typhi) and Gram positive ( Staphylococcus aureus, Bacillus cereus and Micrococcus luteus) bacterial strains. Screening was also performed for any antifungal properties of the nanoparticles against human pathogenic fungal strains ( Candida albicans and Candida parapsilosis). We also demonstrated that these nanoparticles when mixed with shampoo enhance the anti-dandruff effect against dandruff causing fungal pathogens ( Pityrosporum ovale and Pityrosporum folliculitis). The present study showed a simple, rapid and economical route to synthesize silver nanoparticles and their applications hence has a great potential in biomedical field.

  4. Appropriate In Vitro Methods for Genotoxicity Testing of Silver Nanoparticles

    PubMed Central

    Kim, Ha Ryong; Park, Yong Joo; Shin, Da Young; Oh, Seung Min

    2013-01-01

    Objectives We investigated the genotoxic effects of 40-59 nm silver nanoparticles (Ag-NPs) by bacterial reverse mutation assay (Ames test), in vitro comet assay and micronucleus (MN) assay. In particular, we directly compared the effect of cytochalasin B (cytoB) and rat liver homogenate (S9 mix) in the formation of MN by Ag-NPs. Methods Before testing, we confirmed that Ag-NPs were completely dispersed in the experimental medium by sonication (three times in 1 minute) and filtration (0.2 µm pore size filter), and then we measured their size in a zeta potential analyzer. After that the genotoxicity were measured and especially, S9 mix and with and without cytoB were compared one another in MN assay. Results Ames test using Salmonella typhimurium TA98, TA100, TA1535 and TA1537 strains revealed that Ag-NPs with or without S9 mix did not display a mutagenic effect. The genotoxicity of Ag-NPs was also evaluated in a mammalian cell system using Chinese hamster ovary cells. The results revealed that Ag-NPs stimulated DNA breakage and MN formation with or without S9 mix in a dose-dependent manner (from 0.01 µg/mL to 10 µg/mL). In particular, MN induction was affected by cytoB. Conclusions All of our findings, with the exception of the Ames test results, indicate that Ag-NPs show genotoxic effects in mammalian cell system. In addition, present study suggests the potential error due to use of cytoB in genotoxic test of nanoparticles. PMID:23440978

  5. Environmental Fate of Silver Nanoparticles in Boreal Lake Ecosystems.

    PubMed

    Furtado, Lindsay M; Norman, Beth C; Xenopoulos, Marguerite A; Frost, Paul C; Metcalfe, Chris D; Hintelmann, Holger

    2015-07-21

    Silver nanoparticles (AgNPs) are currently the most commonly used nanoparticles in consumer products, yet their environmental fate in natural waters is poorly understood. In the present study, we investigated the persistence, transformations and distribution of polyvinylpyrrolidone (PVP) and citrate (CT) coated AgNPs in boreal lake mesocosms dosed either with a 6-week chronic regimen or a one-time pulse treatment at environmentally relevant dosing levels. In the chronic treatments, total Ag (TAg) concentrations reached ?40% of target concentrations by the end of the experiment, and in the pulsed mesocosms, TAg dissipated slowly, with a half-life of ?20 days. Sediments and periphyton on the mesocosm walls were an important sink for Ag. We found little effect of AgNP loading and surface coating on the persistence of TAg. There were also no differences between treatments in the degree of agglomeration of AgNPs, as indicated by the accumulation and distribution of Ag in the particulate and colloidal fractions. The low ionic strength and relatively high dissolved organic carbon concentrations in the lake water likely contributed to the relative stability of AgNP in the water column. The low concentrations of dissolved Ag (<1 ?g L(-1)) in the size fraction <3 kDaA reflect the importance of natural ligands in controlling the concentrations of Ag released by dissolution of AgNPs. Overall, these data indicate that AgNPs are relatively stable in the tested lake environment and appear to result in quantities of highly toxic ionic Ag(+) that are below our limit of detection. PMID:26061763

  6. XPS analysis of oleylamine/oleic acid capped Fe3O4 nanoparticles as a function of temperature

    NASA Astrophysics Data System (ADS)

    Wilson, D.; Langell, M. A.

    2014-06-01

    Fe3O4 nanoparticles were synthesized solvothermally using oleylamine and oleic acid as surfactants, and the surface composition was determined by X-ray photoelectron spectroscopy (XPS) as a function of temperature, from the as-synthesized nanoparticles to those annealed under vacuum at 883K. XPS of the as-synthesized nanoparticles was consistent with a surface composition of stoichiometric Fe3O4 capped with a mixture of monodentate carboxylate and chemisorbed amine, although the surface was enriched in carboxylate over that present in the synthesis reaction concentration. The method of synthesis and capping surfactants effectively protect the nanoparticle surface from detectable hydroxylation. The capped nanoparticle is stable for 24 h at 373K, and the capping agents persist to 523K, at which point the oleylamine decomposes to desorb nitrogen and deposit aliphatic carbon from the capping tail. The carboxylate decomposes over a wider range and at 883K some carboxylate remains on the surface. The iron oxide nanoparticle undergoes substantial reduction as the aliphatic capping tail decomposes. While the as-introduced nanoparticle is essentially Fe3O4, reduction to FeO, Fe and Fe3C occurs sequentially as the nanoparticle is heated to higher temperatures.

  7. Investigation on the antibacterial micro-porous titanium with silver nano-particles.

    PubMed

    Dong, Wei; Zhu, Yingchun; Zhang, Jingxian; Lu, Liqiang; Zhao, Chengjian; Qin, Lifeng; Li, Yingbin

    2013-10-01

    Micro-porous titanium is coated with silver nanoparticles by using a simple chemical reduction method that exhibits excellent antibacterial ability. Scanning electron microscopy (SEM) shows that the silver nanoparticles with average sizes of about 100 nm are formed homogeneously on the micro-porous titanium surface. After the micro-porous Ti coated with silver nano particles is treated by heating, the average size of the silver nano particles is slightly increased, but the nano particles are more uniformly dispersed on the surface of the micro-porous titanium. X-ray diffraction (XRD) indicates that those nanoparticles are metallic silver produced on the micro-porous titanium surface. The samples of micro-porous titanium coated with silver nanoparticles inhibit the growth of Escherichia coli. Our results show that the electrical double layer of the samples play an important role in the antibiosis and this study opens a new window for antibacterial mechanism which may be suitable for the other antibacterial metallic materials. PMID:24245143

  8. Biosynthesis of silver nanoparticle from leaf extract of Desmodium gangeticum (L.) DC. and its biomedical potential

    NASA Astrophysics Data System (ADS)

    Thirunavoukkarasu, M.; Balaji, U.; Behera, S.; Panda, P. K.; Mishra, B. K.

    2013-12-01

    An aqueous leaf extract of Desmodium gangeticum was employed to synthesize silver nano particles. Rapid formation of stable silver nanoparticles were observed on exposure of the aqueous leaf extract with solution of silver nitrate. The silver nanoparticles were characterized by UV-visible spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis and transmission electron microscopy (TEM), and Fourier Transform Infra-Red spectroscopy (FTIR) UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), and Fourier Transform Infra-Red spectroscopy (FTIR). UV-visible spectrum of the aqueous medium peaked at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. SEM analysis revealed the spherical shape of the particles with sizes ranging from 18 to 39 nm and the EDAX spectrum confirmed the presence of silver along with other elements in the plant metabolite. Further, these biologically synthesized nanoparticles were found to be highly toxic against pathogenic bacteria Escherichia coli, thus implying significance of the present study in production of biomedical products.

  9. Biosynthesis of silver nanoparticle from leaf extract of Desmodium gangeticum (L.) DC. and its biomedical potential.

    PubMed

    Thirunavoukkarasu, M; Balaji, U; Behera, S; Panda, P K; Mishra, B K

    2013-12-01

    An aqueous leaf extract of Desmodium gangeticum was employed to synthesize silver nano particles. Rapid formation of stable silver nanoparticles were observed on exposure of the aqueous leaf extract with solution of silver nitrate. The silver nanoparticles were characterized by UV-visible spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis and transmission electron microscopy (TEM), and Fourier Transform Infra-Red spectroscopy (FTIR) UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), and Fourier Transform Infra-Red spectroscopy (FTIR). UV-visible spectrum of the aqueous medium peaked at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. SEM analysis revealed the spherical shape of the particles with sizes ranging from 18 to 39 nm and the EDAX spectrum confirmed the presence of silver along with other elements in the plant metabolite. Further, these biologically synthesized nanoparticles were found to be highly toxic against pathogenic bacteria Escherichia coli, thus implying significance of the present study in production of biomedical products. PMID:23973589

  10. Silver nanoparticles: synthesis, properties, toxicology, applications and perspectives

    NASA Astrophysics Data System (ADS)

    Tran, Quang Huy; Quy Nguyen, Van; Le, Anh-Tuan

    2013-09-01

    In recent years the outbreak of re-emerging and emerging infectious diseases has been a significant burden on global economies and public health. The growth of population and urbanization along with poor water supply and environmental hygiene are the main reasons for the increase in outbreak of infectious pathogens. Transmission of infectious pathogens to the community has caused outbreaks of diseases such as influenza (A/H5N1), diarrhea (Escherichia coli), cholera (Vibrio cholera), etc throughout the world. The comprehensive treatments of environments containing infectious pathogens using advanced disinfectant nanomaterials have been proposed for prevention of the outbreaks. Among these nanomaterials, silver nanoparticles (Ag-NPs) with unique properties of high antimicrobial activity have attracted much interest from scientists and technologists to develop nanosilver-based disinfectant products. This article aims to review the synthesis routes and antimicrobial effects of Ag-NPs against various pathogens including bacteria, fungi and virus. Toxicology considerations of Ag-NPs to humans and ecology are discussed in detail. Some current applications of Ag-NPs in water-, air- and surface- disinfection are described. Finally, future prospects of Ag-NPs for treatment and prevention of currently emerging infections are discussed.

  11. Silver nanoparticle enhanced chemiluminescence method for the determination of nitrazepam.

    PubMed

    Han, Suqin; Li, Xia; Wei, Bei

    2014-01-01

    We report on a simple and sensitive chemiluminescence (CL) method to determine nitrazepam. This method is based on the fact that rhodamine 6G (Rh6G) enhanced the weak CL emission of the reaction of hexacyanoferrate with nitrazepam, and that it was further enhanced by silver nanoparticles (AgNPs). The effects of the concentrations of K3Fe(CN)6, Rh6G, AgNPs and NaOH on the CL reaction were investigated. Under the optimum conditions, the CL intensity was proportional to the concentration of nitrazepam in the range from 1.0 nM to 10.0 ?M. The detection limit (3?) was at 0.1 nM. The relative standard deviation was 2.1% (at a 0.1 ?M concentration and for n = 11). The method was successfully applied to the determination of nitrazepam in Coca-Cola beverage, urine and plasma, and the recovery was 98 - 103%. We also considered the possible CL reaction mechanism. PMID:24717660

  12. Silver nanoparticles synthesised using plant extracts show strong antibacterial activity.

    PubMed

    Kumari, Avnesh; Guliani, Anika; Singla, Rubbel; Yadav, Ramdhan; Yadav, Sudesh Kumar

    2015-06-01

    In this study, three plants Populus alba, Hibiscus arboreus and Lantana camara were explored for the synthesis of silver nanoparticles (SNPs). The effect of reaction temperature and leaf extract (LE) concentration of P. alba, H. arboreus and L. camara was evaluated on the synthesis and size of SNPs. The SNPs were characterised by ultra-violet-visible spectroscopy, scanning electron microscopy and atomic force microscopy. The synthesis rate of SNPs was highest with LE of L. camara followed by H. arboreus and P. alba under similar conditions. L. camara LE showed maximum potential of smaller size SNPs synthesis, whereas bigger particles were formed by H. arboreous LE. The size and shape of L. camara LE synthesised SNPs were analysed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). TEM analysis revealed the formation of SNPs of average size 17 ± 9.5 nm with 5% LE of L. camara. The SNPs synthesised by LE of L. camara showed strong antibacterial activity against Escherichia coli. The results document that desired size SNPs can be synthesised using these plant LEs at a particular temperature for applications in the biomedical field. PMID:26023158

  13. Antibacterial activity of silver nanoparticles grafted on stone surface.

    PubMed

    Bellissima, F; Bonini, M; Giorgi, R; Baglioni, P; Barresi, G; Mastromei, G; Perito, B

    2014-12-01

    Microbial colonization has a relevant impact on the deterioration of stone materials with consequences ranging from esthetic to physical and chemical changes. Avoiding microbial growth on cultural stones therefore represents a crucial aspect for their long-term conservation. The antimicrobial properties of silver nanoparticles (AgNPs) have been extensively investigated in recent years, showing that they could be successfully applied as bactericidal coatings on surfaces of different materials. In this work, we investigated the ability of AgNPs grafted to Serena stone surfaces to inhibit bacterial viability. A silane derivative, which is commonly used for stone consolidation, and Bacillus subtilis were chosen as the grafting agent and the target bacterium, respectively. Results show that functionalized AgNPs bind to stone surface exhibiting a cluster disposition that is not affected by washing treatments. The antibacterial tests on stone samples revealed a 50 to 80 % reduction in cell viability, with the most effective AgNP concentration of 6.7 ?g/cm(2). To our knowledge, this is the first report on antimicrobial activity of AgNPs applied to a stone surface. The results suggest that AgNPs could be successfully used in the inhibition of microbial colonization of stone artworks. PMID:24151026

  14. Silver nanoparticle-induced degranulation observed with quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Yang, Wenzhong; Lee, Seungrag; Lee, Jiyong; Bae, Yoonsung; Kim, Dugyoung

    2010-07-01

    Monitoring a degranulation process in a live mast cell is a quite important issue in immunology and pharmacology. Because the size of a granule is normally much smaller than the resolution limit of an optical microscope system, there is no direct real-time live cell imaging technique for observing degranulation processes except for fluorescence imaging techniques. In this research, we propose optical quantitative phase microscopy (QPM) as a new observation tool to study degranulation processes in a live mast cell without any fluorescence labeling. We measure the cell volumes and the cross sectional profiles (x-z plane) of an RBL-2H3 cell and a HeLa cell, before and after they are exposed to calcium ionophore A23187 and silver nanoparticles (AgNPs). We verify that the volume and the cross sectional line profile of the RBL-2H3 cell were changed significantly when it was exposed to A23187. When 50 ?g/mL of AgNP is used instead of A23187, the measurements of cell volume and cross sectional profiles indicate that RBL-2H3 cells also follow degranulation processes. Degranulation processes for these cells are verified by monitoring the increase of intracellular calcium ([Ca2+]i) and histamine with fluorescent methods.

  15. Source of cytotoxicity in a colloidal silver nanoparticle suspension.

    PubMed

    Hatipoglu, Manolya Kukut; Kele?temur, Seda; Altunbek, Mine; Culha, Mustafa

    2015-05-15

    Silver nanoparticles (AgNPs) are increasingly used in a variety of applications because of their potential antimicrobial activity and their plasmonic and conductivity properties. In this study, we investigated the source of cytotoxicity, genotoxicity, and reactive oxygen species (ROS) production on human dermal fibroblast and human lung cancer (A549) cell lines upon exposure to AgNP colloidal suspensions prepared with the simplest and most commonly used Lee–Meisel method with a variety of reaction times and the concentrations of the reducing agent. The AgNPs synthesized with shorter reaction times were more cytotoxic and genotoxic due to the presence of a few nanometer-sized AgNP seeds. The suspensions prepared with an increased citrate concentration were not cytotoxic, but they induced more ROS generation on A549 cells due to the high citrate concentration. The genotoxicity of the suspension decreased significantly at the higher citrate concentrations. The analysis of both transmission electron microscopy images from the dried droplet areas of the colloidal suspensions and toxicity data indicated that the AgNP seeds were the major source of toxicity. The completion of the nucleation step and the formation of larger AgNPs effectively decreased the toxicity. PMID:25904404

  16. Alkyne-functionalized superstable graphitic silver nanoparticles for Raman imaging.

    PubMed

    Song, Zhi-Ling; Chen, Zhuo; Bian, Xia; Zhou, Li-Yi; Ding, Ding; Liang, Hao; Zou, Yu-Xiu; Wang, Shan-Shan; Chen, Long; Yang, Chao; Zhang, Xiao-Bing; Tan, Weihong

    2014-10-01

    Noble metals, especially gold, have been widely used in plasmon resonance applications. Although silver has a larger optical cross section and lower cost than gold, it has attracted much less attention because of its easy corrosion, thereby degrading plasmonic signals and limiting its applications. To circumvent this problem, we report the facile synthesis of superstable AgCu@graphene (ACG) nanoparticles (NPs). The growth of several layers of graphene onto the surface of AgCu alloy NPs effectively protects the Ag surface from contamination, even in the presence of hydrogen peroxide, hydrogen sulfide, and nitric acid. The ACG NPs have been utilized to enhance the unique Raman signals from the graphitic shell, making ACG an ideal candidate for cell labeling, rapid Raman imaging, and SERS detection. ACG is further functionalized with alkyne-polyethylene glycol, which has strong Raman vibrations in the Raman-silent region of the cell, leading to more accurate colocalization inside cells. In sum, this work provides a simple approach to fabricate corrosion-resistant, water-soluble, and graphene-protected AgCu NPs having a strong surface plasmon resonance effect suitable for sensing and imaging. PMID:25233109

  17. Proteomics study of silver nanoparticles toxicity on Oryza sativa L.

    PubMed

    Mirzajani, Fateme; Askari, Hossein; Hamzelou, Sara; Schober, Yvonne; Römpp, Andreas; Ghassempour, Alireza; Spengler, Bernhard

    2014-10-01

    The increasing use of silver nanoparticles, (AgNPs), will inevitably result in their release into the environment and thereby cause the exposure to plants. It was claimed that using AgNPs is a safe and efficient method to preserve and treat agents of disease in agriculture. This study tries to understand the protein populations and sub-populations and follow up environmental AgNPs stresses. To accomplish these, the action of homemade spherical AgNPs colloidal suspension against Oryza sativa L. was investigated by a proteomic approach (2-DE and NanoLC/FT-ICR MS identification). Twenty-eight responsive (decrement/increment in abundance) proteins were identified. Proteomic results revealed that an exposure of O. sativa L., root with different concentrations of AgNPs resulted in an accumulation of protein precursors, indicative of the dissipation of a proton motive force. The identified proteins are involved in oxidative stress tolerance, Ca(2+) regulation and signaling, transcription and protein degradation, cell wall and DNA/RNA/protein direct damage, cell division and apoptosis. The expression pattern of these proteins and their possible involvement in the nontoxicity mechanisms were discussed. PMID:25124680

  18. Biosynthesis of silver nanoparticles by phytopathogen Xanthomonas oryzae pv. oryzae strain BXO8.

    PubMed

    Narayanan, Kannan Badri; Sakthivel, Natarajan

    2013-09-28

    Extracellular biogenic synthesis of silver nanoparticles with various shapes using the rice bacterial blight bacterium Xanthomonas oryzae pv. oryzae BXO8 is reported. The synthesized silver nanoparticles were characterized by UV-Vis spectroscopy, powder X-ray diffractometry (XRD), scanning electron microscopy, energy dispersive X-ray spectrometry, and highresolution transmission electron microscopy (HR-TEM). Based on the evidence of HR-TEM, the synthesized particles were found to be spherical, with anisotropic structures such as triangles and rods, with an average size of 14.86 nm. The crystalline nature of silver nanoparticles was evident from the bright circular spots in the SAED pattern, clear lattice fringes in the high-resolution TEM images, and peaks in the XRD pattern. The FTIR spectrum showed that biomolecules containing amide and carboxylate groups are involved in the reduction and stabilization of the silver nanoparticles. Using such a biological method for the synthesis of silver nanoparticles is a simple, viable, cost-effective, and environmentally friendly process, which can be used in antimicrobial therapy. PMID:23751558

  19. Green synthesis of silver nanoparticles using Terminalia chebula extract at room temperature and their antimicrobial studies

    NASA Astrophysics Data System (ADS)

    Mohan Kumar, Kesarla; Sinha, Madhulika; Mandal, Badal Kumar; Ghosh, Asit Ranjan; Siva Kumar, Koppala; Sreedhara Reddy, Pamanji

    2012-06-01

    A green rapid biogenic synthesis of silver nanoparticles (Ag NPs) using Terminalia chebula (T. chebula) aqueous extract was demonstrated in this present study. The formation of silver nanoparticles was confirmed by Surface Plasmon Resonance (SPR) at 452 nm using UV-visible spectrophotometer. The reduction of silver ions to silver nanoparticles by T. chebula extract was completed within 20 min which was evidenced potentiometrically. Synthesised nanoparticles were characterised using UV-vis spectroscopy, Fourier transformed infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The hydrolysable tannins such as di/tri-galloyl-glucose present in the extract were hydrolyzed to gallic acid and glucose that served as reductant while oxidised polyphenols acted as stabilizers. In addition, it showed good antimicrobial activity towards both Gram-positive bacteria (S. aureus ATCC 25923) and Gram-negative bacteria (E. coli ATCC 25922). Industrially it may be a smart option for the preparation of silver nanoparticles.

  20. Assessing orally bioavailable commercial silver nanoparticle product on human cytochrome P450 enzyme activity.

    PubMed

    Munger, Mark A; Hadlock, Greg; Stoddard, Greg; Slawson, Matthew H; Wilkins, Diana G; Cox, Nicholas; Rollins, Doug

    2015-05-01

    Nanotechnology produces a wide range of medicinal compounds, including nanoparticulate silver, which are increasingly introduced in various forms for consumer use. As with all medicinal compounds, potential drug interactions are an important consideration for ingested silver nanoparticles. Nanoparticulate silver-drug interactions may be mediated through induced oxidative stress in liver tissue where the majority of systemically bioavailable silver nanoparticles is found. To investigate whether an orally ingested commercially available colloidal silver nanoproduct produces pharmacokinetic interference on select cytochrome P450 enzymes, a prospective, single-blind, controlled in vivo human study using simultaneous administration of standardized probes for P450 enzyme classes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 was conducted. Oral ingestion of a commercial colloidal silver nanoproduct produces detectable silver in human serum after 14 days of dosing. This silver, however, elicits no demonstrable clinically significant changes in metabolic, hematologic, urinary, physical findings or cytochrome P450 enzyme inhibition or induction activity. Given their increasingly broad, diverse human exposures, future characterization of human cytochrome P450 enzyme activity for other systemically bioavailable nanotechnology products are warranted. PMID:25137296

  1. Greener Techniques for the Synthesis of Silver Nanoparticles Using Plant Extracts, Enzymes, Bacteria, Biodegradable Polymers, and Microwaves

    EPA Science Inventory

    The use of silver nanoparticles (AgNPs) is gaining in popularity due to silver?s antibacterial properties. Conventional methods for AgNP synthesis require dangerous chemicals and large quantities of energy (heat) and can result in formation of hazardous by-products. This article ...

  2. GREEN SYNTHESIS OF SILVER AND PALLADIUM NANOPARTICLES AT ROOM TEMPERATURE USING COFFEE AND TEA EXTRACT

    EPA Science Inventory

    An extremely simple green approach that generates bulk quantities of nanocrystals of noble metals such as silver (Ag) and palladium (Pd) using coffee and tea extract at room temperature is described. The single-pot method uses no surfactant, capping agent, and/or template. The ob...

  3. Synthesis of monodisperse, quasi-spherical silver nanoparticles with sizes defined by the nature of silver precursors.

    PubMed

    Li, Houshen; Xia, Haibing; Ding, Wenchao; Li, Yijing; Shi, Qiurong; Wang, Dayang; Tao, Xutang

    2014-03-11

    Monodisperse, quasi-spherical silver nanoparticles (Ag NPs) with controlled sizes have been produced directly in water via adding the aqueous solutions of the mixtures of AgNO3 and sodium citrate to boiling aqueous solutions of ascorbic acid (AA). Different compounds, including NaCl, NaBr, KI, Na2SO4, Na2CO3, Na2S, and Na3PO4, are added to the AgNO3/citrate mixture solutions to form new silver compounds with fairly low solubility in water, which are used as precursors instead of soluble Ag(+) ions to synthesize Ag NPs via AA/citrate reduction. This enables us not only to produce monodisperse, quasi-spherical Ag NPs but also to tune the sizes of the resulting NPs from 16 to 30 nm according to the potential of new silver precursors as well as the concentrations of anions. PMID:24528373

  4. Substrate effect on refractive index dependence of plasmon resonance for individual silver nanoparticles observed using darkfield microspectroscopy

    Microsoft Academic Search

    A. Curry; G. Nusz; A. Chilkoti; Adam Wax

    2005-01-01

    We use optical darkfield micro-spectroscopy to characterize the plasmon resonance of individual silver nanoparticles in the presence of a substrate. The optical system permits multiple individual nanoparticles to be identified visually for simultaneous spectroscopic study. For silver particles bound to a silanated glass substrate, we observe changes in the Plasmon resonance due to induced variations in the local refractive index.

  5. Preparation of amino functionalized silica micro beads by dry method for supporting silver nanoparticles with antibacterial properties

    Microsoft Academic Search

    Dang Viet Quang; Pradip B. Sarawade; Askwar Hilonga; Jong-Kil Kim; Young Gyu Chai; Sang Hoon Kim; Jae-Yong Ryu; Hee Taik Kim

    2011-01-01

    The development of resistance to antibiotics and disinfectants as well as the occurrence of many adverse effects caused by using conventional antibacterial agents like chlorine compounds have prompted scientists to search for new antibacterial agents. Among the many nanomaterials, silver nanoparticles have proven to be a good alternative for its antibacterial properties. In this study, silver nanoparticle-supported silica micro beads

  6. Role of silver nanoparticles in the laser-induced reversible colour-marking and controlled crystallization of mesoporous titania films

    Microsoft Academic Search

    N. Crespo-Monteiro; N. Destouches; E. Gamet; L. Bois; F. Chassagneux; L. Nadar; F. Vocanson

    2011-01-01

    Due to their surface plasmon resonance silver nanoparticles are known to absorb visible light and give glasses various colors. Grown in mesoporous titania films, they give the material a photochromic behaviour that can be used to produce rewritable data carriers. On the one hand, UV light forms silver nanoparticles thanks to the photo-induced generation of electrons by titania matrix. On

  7. Synthesis and effect of silver nanoparticles on the antibacterial activity of different antibiotics against Staphylococcus aureus and Escherichia coli

    Microsoft Academic Search

    Ahmad R. Shahverdi; Ali Fakhimi; Hamid R. Shahverdi; Sara Minaian

    2007-01-01

    Silver nanoparticles (Ag-NPs) have been known to have inhibitory and bactericidal effects. Resistance to antimicrobial agents by pathogenic bacteria has emerged in recent years and is a major health problem. The combination effects of Ag-NPs with the antibacterial activity of antibiotics have not been studied. Here, we report on the synthesis of metallic nanoparticles of silver using a reduction of

  8. Rapid preparation process of antiparkinsonian drug Mucuna pruriens silver nanoparticle by bioreduction and their characterization

    PubMed Central

    Arulkumar, Subramanian; Sabesan, Muthukumaran

    2010-01-01

    Backgorund: Development of biologically inspired experimental processes for the synthesis of nanoparticles is evolving an important branch of nanotechnology. Methods: The bioreduction behavior of plant seed extract of Mucuna pruriens in the synthesis of silver nanoparticles was investigated employing UV/visible spectrophotometry, X-ray diffraction (XRD), and transmission electron microscopy (TEM), Fourier transform – infra red (FT- IR). Result: M. pruriens was found to exhibit strong potential for rapid reduction of silver ions. The formation of nanoparticles by this method is extremely rapid, requires no toxic chemicals, and the nanoparticles are stable for several months. Conclusion: The main conclusion is that the bioreduction method to produce nanoparticles is a good alternative to the electrochemical methods and it is expected to be biocompatible. PMID:21808573

  9. The study of the antimicrobial activity of colloidal solutions of silver nanoparticles prepared using food stabilizers.

    PubMed

    Balandin, G V; Suvorov, O A; Shaburova, L N; Podkopaev, D O; Frolova, Yu V; Ermolaeva, G A

    2015-06-01

    The bactericidal effect of colloidal solutions of silver nanoparticles based on food stabilizers, gum arabic and chitosan, against bacterial cultures of microorganisms in food production is described. The antibacterial activity of nanotechnology products containing different amounts of stabilizing additives when applied to solid pH-neutral substrates is studied. For its evaluation a method making it possible to take into account the capability of nanoparticles to diffuse in solid media was applied. Minimal inhibitory concentrations of nanoparticles used against Erwinia herbicola, Pseudomonas fluorescens, Bacillus subtilis, Sarcina flava were found. A suggestion was made concerning the influence of the spatial structure of bacteria on the antibacterial activity of colloidal solutions of silver nanoparticles. The data concerning the antibacterial activity and minimal inhibiting concentrations of nanoparticles may be used for development of products suppressing activity of microorganisms hazardous for food production. PMID:26028773

  10. Biosynthesis of silver nanoparticles from the marine seaweed Sargassum wightii and their antibacterial activity against some human pathogens

    NASA Astrophysics Data System (ADS)

    Shanmugam, N.; Rajkamal, P.; Cholan, S.; Kannadasan, N.; Sathishkumar, K.; Viruthagiri, G.; Sundaramanickam, A.

    2014-10-01

    In this paper, we have reported on biological synthesis of nano-sized silver and its antibacterial activity against human pathogens. The nanoparticles of silver were formed by the reduction of silver nitrate to aqueous silver metal ions during exposure to the extract of marine seaweed Sargassum wightii. The optical properties of the obtained silver nanoparticles were characterized using UV-visible absorption and room temperature photoluminescence. The X-ray diffraction results reveal that the synthesized silver nanoparticles are in the cubic phase. The existence of functional groups was identified using Fourier transform infrared spectroscopy. The morphology and size of the synthesized particles were studied with atomic force microscope and high-resolution transmission electron microscope measurements. The synthesized nanoparticles have an effective antibacterial activity against S. aureus, K. pneumoniae, and S. typhi.

  11. Extracellular synthesis of silver nanoparticles by novel Pseudomonas veronii AS41G inhabiting Annona squamosa L. and their bactericidal activity

    NASA Astrophysics Data System (ADS)

    Baker, Syed; Mohan Kumar, K.; Santosh, P.; Rakshith, D.; Satish, S.

    2015-02-01

    In present investigation extracellular synthesis of silver nanoparticles were synthesized using cell free supernatant of Pseudomonas veronii AS41G isolated from Annona squamosa L. The bacterium significantly reduced silver nitrate to generate silver nanoparticles which was characterized with hyphenated techniques. Synthesis of silver nanoparticles preliminary confirmed by UV-Visible spectrophotometry with the intense peak at 410 nm, Further FTIR analysis revealed the possible role of biomolecules in the supernatant responsible for mediating the nanoparticles formation. The XRD spectra exhibited the characteristic Bragg peaks of 1 0 0, 1 1 1, 2 0 0, and 2 2 0 facets of the face centred cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. TEM microgram showed polydispersity of nanoparticles with size ranging from 5 to 50 nm. Synthesized silver nanoparticles showed antibacterial activity against human and environmental pathogens including MRSA. The study enlightens the role of biosynthesized silver nanoparticles as an emerging alternative for drug resistant microorganisms. The obtained results are promising enough to pave the environmentally benign nanoparticle synthesis processes without use of any toxic chemicals and also envision the emerging role of endophytes towards synthesis of nanoparticles. With scanty reports available on P.veronii species, a new role has been reported in this study which will be very valuable for future researchers working on it.

  12. Immobilized silver nanoparticles enhance contact killing and show highest efficacy: elucidation of the mechanism of bactericidal action of silver.

    PubMed

    Agnihotri, Shekhar; Mukherji, Soumyo; Mukherji, Suparna

    2013-08-21

    Antimicrobial materials with immobilized/entrapped silver nanoparticles (AgNPs) are of considerable interest. There is significant debate on the mode of bactericidal action of AgNPs, and both contact killing and/or ion mediated killing have been proposed. In this study, AgNPs were immobilized on an amine-functionalized silica surface and their bactericidal activity was studied concurrently with the silver release profile over time. This was compared with similar studies performed using colloidal AgNPs and AgCl surfaces that released Ag ions. We conclude that contact killing is the predominant bactericidal mechanism and surface immobilized nanoparticles show greater efficacy than colloidal AgNPs, as well as a higher concentration of silver ions in solution. In addition, the AgNP immobilized substrate was used multiple times with good efficacy, indicating this immobilization protocol is effective for retaining AgNPs while maintaining their disinfection potential. The antibacterial surface was found to be extremely stable in aqueous medium and no significant leaching (?1.15% of total silver deposited) of the AgNPs was observed. Thus, immobilization of AgNPs on a surface may promote reuse, reduce environmental risks associated with leaching of AgNPs and enhance cost effectiveness. PMID:23821237

  13. Characterisation of biosynthesised silver nanoparticles by scanning electrochemical microscopy (SECM) and voltammetry.

    PubMed

    Battistel, Dario; Baldi, Franco; Gallo, Michele; Faleri, Claudia; Daniele, Salvatore

    2015-01-01

    Silver nanoparticles (AgNPs) were biosynthesised by a Klebsiella oxytoca strain BAS-10, which, during its growth, is known to produce a branched exopolysaccharide (EPS). Klebsiella oxytoca cultures, treated with AgNO3 and grown under either aerobic or anaerobic conditions, produced silver nanoparticles embedded in EPS (AgNPs-EPS) containing different amounts of Ag(0) and Ag(I) forms. The average size of the AgNPs-EPS was determined by transmission electron microscopy, while the relative abundance of Ag(0)- or Ag(I)-containing AgNPs-EPS was established by scanning electrochemical microscopy (SECM). Moreover, the release of silver(I) species from the various types of AgNPs-EPS was investigated by combining SECM with anodic stripping voltammetry. These measurements allowed obtaining information on the kinetic of silver ions release from AgNPs-EPS and their concentration profiles at the substrate/water interface. PMID:25476311

  14. A comparative study on the adsorption behaviors of PABA in the silver nano-particles

    NASA Astrophysics Data System (ADS)

    Yan, Bin; Fang, Yan; Zhao, XinFeng; Liang, LiNa

    2014-09-01

    Surface-enhanced Raman scattering (SERS) spectra of P-Aminobenzoic Acid (PABA) adsorbed on the silver nano-particles were studied, respectively, in the silver colloidal solution and on the dried silver-coated filter paper. To further study the adsorption behaviors of PABA on the different substrates, we analyze the problem by means of theoretical calculation. Five models of PABA adsorbed on the surfaces of silver nano-particles were established. The Raman spectra of these five models using DFT-B3PW91 with lanl2dz were calculated. By comparing the theoretical values with the experimental values, we found that the calculated Raman frequencies of the models were in good agreement with experimental values, respectively. So we can believe that the simplified models are probably reasonable to describe some surface- enhanced Raman experiments.

  15. Self-assembly of silver nano-particles on stearic acid Langmuir–Blodgett film: evidence of fractal growth

    Microsoft Academic Search

    Jyotirmoy Sarkar; Prabir Pal; G. B. Talapatra

    2005-01-01

    A new technique has been developed to make Langmuir–Blodgett films (LB) on solid substrate containing silver nano-particle clusters. It is based on electrostatic attraction between negatively charged acid groups of stearic acid and positively charged silver nano-particles in silver sol. TEM picture shows that the cluster growth is fractal in nature of dimensions ranging from 1.4 to 1.8 depending on

  16. Particle-Cell Contact Enhances Antibacterial Activity of Silver Nanoparticles

    PubMed Central

    Bondarenko, Olesja; Ivask, Angela; Käkinen, Aleksandr; Kurvet, Imbi; Kahru, Anne

    2013-01-01

    Background It is generally accepted that antibacterial properties of Ag nanoparticles (AgNPs) are dictated by their dissolved fraction. However, dissolution-based concept alone does not fully explain the toxic potency of nanoparticulate silver compared to silver ions. Methodology/Principal Findings Herein, we demonstrated that the direct contact between bacterial cell and AgNPs' surface enhanced the toxicity of nanosilver. More specifically, cell-NP contact increased the cellular uptake of particle-associated Ag ions – the single and ultimate cause of toxicity. To prove that, we evaluated the toxicity of three different AgNPs (uncoated, PVP-coated and protein-coated) to six bacterial strains: Gram-negative Escherichia coli, Pseudomonas fluorescens, P. putida and P. aeruginosa and Gram-positive Bacillus subtilis and Staphylococcus aureus. While the toxicity of AgNO3 to these bacteria varied only slightly (the 4-h EC50 ranged from 0.3 to 1.2 mg Ag/l), the 4-h EC50 values of protein-coated AgNPs for various bacterial strains differed remarkably, from 0.35 to 46 mg Ag/l. By systematically comparing the intracellular and extracellular free Ag+ liberated from AgNPs, we demonstrated that not only extracellular dissolution in the bacterial test environment but also additional dissolution taking place at the particle-cell interface played an essential role in antibacterial action of AgNPs. The role of the NP-cell contact in dictating the antibacterial activity of Ag-NPs was additionally proven by the following observations: (i) separation of bacterial cells from AgNPs by particle-impermeable membrane (cut-off 20 kDa, ?4 nm) significantly reduced the toxicity of AgNPs and (ii) P. aeruginosa cells which tended to attach onto AgNPs, exhibited the highest sensitivity to all forms of nanoparticulate Ag. Conclusions/Significance Our findings provide new insights into the mode of antibacterial action of nanosilver and explain some discrepancies in this field, showing that “Ag-ion” and “particle-specific” mechanisms are not controversial but, rather, are two faces of the same coin. PMID:23737965

  17. Synthesis of silver nanoparticle at a gas/liquid interface in the presence of silver seeds and its application for electrochemical sensing.

    PubMed

    Yang, Ziyin; Qi, Chengcheng; Zheng, Xiaohui; Zheng, Jianbin

    2015-08-01

    Silver nanoparticles were synthesized by reducing [Ag(NH3)2](+) at a gas/liquid interface in the presence of silver seeds. Transmission electron microscopy (TEM) observations reveal that the size of these silver nanoparticles is around 35-40nm with the average particle size of 37nm. The silver nanoparticles were applied for the electrochemical sensor and electrochemical investigations indicate that the nanoparticles possess an excellent performance toward H2O2. The linear range is estimated to be from 5.0?M to 4.0mM with a low detection limit of 1.7?M, a sensitivity of 166.7?AmM(-1)cm(-2) and a response time of 3s. Additionally, the sensor exhibits good anti-interference. PMID:26048842

  18. Structural distortions in 5-10 nm silver nanoparticles under high pressure

    SciTech Connect

    Koski, Kristie J.; Kamp, Noelle M.; Kunz, Martin; Knight, Jason K.; Alivisatos, A.P.; Smith, R.K.

    2008-10-13

    We present experimental evidence that silver nanoparticles in the size range of 5-10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. We have used x-ray diffraction with a synchrotron light source to investigate pressure-dependent and size-dependent trends in the crystal structure of silver nanoparticles in a hydrostatic medium compressed in a diamond-anvil cell. Results suggest a reversible linear pressure-dependent rhombohedral distortion which has not been previously observed in bulk silver. We propose a mechanism for this transition that considers the bond-length distribution in idealized multiply twinned icosahedral particles. To further support this hypothesis, we also show that similar measurements of single-crystal platinum nanoparticles reveal no such distortions.

  19. Structural distortions in 5-10 nm silver nanoparticles under high pressure

    NASA Astrophysics Data System (ADS)

    Koski, K. J.; Kamp, N. M.; Smith, R. K.; Kunz, M.; Knight, J. K.; Alivisatos, A. P.

    2008-10-01

    We present experimental evidence that silver nanoparticles in the size range of 5-10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. We have used x-ray diffraction with a synchrotron light source to investigate pressure-dependent and size-dependent trends in the crystal structure of silver nanoparticles in a hydrostatic medium compressed in a diamond-anvil cell. Results suggest a reversible linear pressure-dependent rhombohedral distortion which has not been previously observed in bulk silver. We propose a mechanism for this transition that considers the bond-length distribution in idealized multiply twinned icosahedral particles. To further support this hypothesis, we also show that similar measurements of single-crystal platinum nanoparticles reveal no such distortions.

  20. Different quantum optical response in fluorescence of gold and silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Bagheri, Zahra; Allameh, Ziba; Massudi, Reza

    2015-06-01

    Electrical permittivity and fluorescence emission behavior of gold and silver nanoparticles with radii range from 1 to 10 nm are studied in quantum mechanical regime and compared with classical results. It is observed that electrical permittivity of gold and silver nanoparticles is significantly modified considering quantum mechanical effects. Furthermore, it varies by wavelength while the size of nanoparticles decreases. The results indicate clear blue shift for silver and red shift for gold and also weakening of fluorescence peaks for both types of nanospheres. These quantum plasmonics particles which can pass through walls of living cells due to their small size can also serve as a fluorescent probe and delivery system for imaging and targeted delivery of bio-systems.

  1. An original nitrate sensor based on silver nanoparticles electrodeposited on a gold electrode

    Microsoft Academic Search

    Katia Fajerwerg; Vaiata Ynam; Bruno Chaudret; Véronique Garçon; Danièle Thouron; Maurice Comtat

    2010-01-01

    The electroreduction of nitrate in synthetic seawater was investigated by cyclic voltammetry (CV) at a bare gold electrode modified by electrodeposited silver nanoparticles (AgNPs). The AgNPs were generated by chronoamperometry using a charge, Q, lower than the theoretical one corresponding to a silver monolayer. In these conditions, a linear range for nitrate determination is obtained from 10·10-6molL-1 to 10·10-3molL-1. Such

  2. Preparation of silver nanoparticle containing silica micro beads and investigation of their antibacterial activity

    Microsoft Academic Search

    Dang Viet Quang; Pradip B. Sarawade; Askwar Hilonga; Jong-Kil Kim; Young Gyu Chai; Sang Hoon Kim; Jae-Yong Ryu; Hee Taik Kim

    2011-01-01

    Silver nanoparticle containing silica micro beads (Ag-NPBs) were successfully prepared by using sodium silicate, a cheap precursor, involving chemical reductive method. First, silica gel was synthesized and crushed into micro beads which have sizes ranging from 0.5 to 1mm. Silica micro beads were then modified with 3-aminopropyltriethoxysilane to graft amino functional groups onto their surface. Silver ions were loaded onto

  3. Antioxidant properties of biohybrids based on liposomes and sage silver nanoparticles.

    PubMed

    Barbinta-Patrascu, Marcela Elisabeta; Bunghez, Ioana-Raluca; Iordache, Stefan Marian; Badea, Nicoleta; Fierascu, Radu-Claudiu; Ion, Rodica Mariana

    2013-03-01

    This paper is aimed to describe a simple and rapid eco-friendly bottom-up approach for the preparation of antioxidant silver bionanostructures using a leaf extract from sage (Salvia officinalis L.). The bioreduction property of sage in the synthesis of silver nanoparticles was investigated by UV-VIS and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy. During their preparation, the particle size analysis was performed by using Dynamic Light Scattering technique. Ultrasonic irradiation was used to obtain sage silver nanoparticles. The morphology (size and shape) of the herbal silver nanoparticles was evaluated by Scanning Electron Microscopy that revealed the formation of spherical phytonanoparticles with size less than 80 nm. In order to increase their stability and their biocompatibility, the sage silver nanoparticles were introduced in two types of liposomes: soybean lecithin- and Chla-DPPC-lipid vesicles which were prepared by thin film hydration method. X-Ray Fluorescence analysis confirmed the silver presence in liposomes/sage-AgNPs biohybrids. The stability of liposomes/herbal AgNPs bioconstructs was checked by zeta potential measurements. The most stable biohybrids: Chla-DPPC/sage-AgNPs with zeta potential value of -34.2 mV, were characterized by Atomic Force Microscopy revealing the spherical and quasi-spherical shaped profiles of these nanobiohybrids with size less than 96 nm. The antioxidant activity of the silver bionanostructures was evaluated using chemiluminescence assay. The developed eco-friendly silver phytonanostructures based on lipid membranes, nanosilver and sage extract, manifest strong antioxidant properties (between 86.5% and 98.6%). PMID:23755645

  4. Continuous synthesis of colloidal silver nanoparticles by electrochemical discharge in aqueous solutions

    Microsoft Academic Search

    Kuo-Hsiung Tseng; Yu-Chun Chen; Jing-Jong Shyue

    2011-01-01

    This article presents an electrochemical discharge (ECD) method that consists of a combination of chemical methods and electric\\u000a arc discharges. In the method, 140 V is applied to an Ag electrode from a DC power supply. The arc-discharge between the electrodes\\u000a produces metallic silver nanoparticles and silver ions in the aqueous solution. Compared with the original arc discharge,\\u000a this ECD method

  5. Reversible dispersion and aggregation of Ag2S nanoparticles capped with azobenzene-derivatized alkanethiols.

    PubMed

    Ishisone, Takahiro; Endo, Hiroshi; Kawai, Takeshi

    2012-01-01

    Ag2S nanoparticles (NPs) of 3.1 +/- 0.6, 8.1 +/- 1.0, and 10.2 +/- 1.6 nm in diameter capped with a long-chain amidoamine derivative (C18AA) were synthesized by a modified Brust method. Ag2S NPs capped with two types of azobenzene-derivatized alkanethiol differing in chain length (2AM10SH and 8AM5SH) were obtained by the ligand exchange method. The trans to cis photoisomerization conversion of 2AM10SH and 8AM5SH on Ag2S NPs dispersed in toluene was above 95%. 2AM10SH-capped Ag2S NPs of 8.1 nm or more in toluene were found to show reversible dispersion-aggregation behavior under alternating irradiation with UV and visible lights, i.e., Ag2S NPs capped with trans- and cis-2AM10SH were in dispersed and aggregated states, respectively. However, Ag2S NPs of 3.1 nm capped with 2AM10SH and Ag2S NPs of 8.1 nm capped with 8AM5SH were always in a dispersed state regardless of whether 2AM10SH and 8AM5SH were in the trans or cis conformation. PMID:22524034

  6. Powerful colloidal silver nanoparticles for the prevention of gastrointestinal bacterial infections

    NASA Astrophysics Data System (ADS)

    Le, Anh-Tuan; Tam Le, Thi; Quy Nguyen, Van; Hoang Tran, Huy; Dang, Duc Anh; Tran, Quang Huy; Vu, Dinh Lam

    2012-12-01

    In this work we have demonstrated a powerful disinfectant ability of colloidal silver nanoparticles (NPs) for the prevention of gastrointestinal bacterial infections. The silver NPs colloid was synthesized by a UV-enhanced chemical precipitation. Two gastrointestinal bacterial strains of Escherichia coli (ATCC 43888-O157:k-:H7) and Vibrio cholerae (O1) were used to verify the antibacterial activity of the as-prepared silver NPs colloid by means of surface disinfection assay in agar plates and turbidity assay in liquid media. Transmission electron microscopy was also employed to analyze the ultrastructural changes of bacterial cells caused by silver NPs. Noticeably, our silver NPs colloid displayed a highly effective bactericidal effect against two tested gastrointestinal bacterial strains at a silver concentration as low as ˜3 mg l?1. More importantly, the silver NPs colloid showed an enhancement of antibacterial activity and long-lasting disinfectant effect as compared to conventional chloramin B (5%) disinfection agent. These advantages of the as-prepared colloidal silver NPs make them very promising for environmental treatments contaminated with gastrointestinal bacteria and other infectious pathogens. Moreover, the powerful disinfectant activity of silver-containing materials can also help in controlling and preventing further outbreak of diseases.

  7. Intracellular synthesis of silver nanoparticle by actinobacteria and its antimicrobial activity.

    PubMed

    Otari, S V; Patil, R M; Ghosh, S J; Thorat, N D; Pawar, S H

    2015-02-01

    Intracellular synthesis of silver nanoparticles (AgNPs) using Rhodococcus spp. is demonstrated. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, X-ray diffraction, energy dispersive spectroscopy, Fourier trans-form infrared spectroscopy, and transmission electron microscopy. Transmission electron microscopy study of microorganisms' revealed synthesis of nanoparticle was occurring inside the cell, in the cytoplasm. AgNPs ranged from 5 to 50 nm. Formed nanoparticles were stable in the colloidal solution due to presence of proteins on the surface. AgNPs showed excellent bactericidal and bacteriostatic activity against pathogenic microorganisms. PMID:25456659

  8. Further evidence of the anti-inflammatory effects of silver nanoparticles.

    PubMed

    Wong, Kenneth K Y; Cheung, Stephanie O F; Huang, Liuming; Niu, Jun; Tao, Chang; Ho, Chi-Ming; Che, Chi-Ming; Tam, Paul K H

    2009-07-01

    The production of pure silver in nanoparticle size has opened new dimensions in the clinical use of this precious metal. We and others have demonstrated previously that silver nanoparticles (nAg) possess efficient antimicrobial activity. Herein we show they may also have significant anti-inflammatory effects in a postoperative peritoneal adhesion model. This finding provides further insight into the biological actions of nAg as well as a potentially novel therapy for peritoneal adhesions in clinical surgery.With the advent of nanoscience, pure silver can now be made into nanometer-sized particles. As a result, we are able to explore the potentially beneficial properties of pure silver. In our previous study using a burn wound model in mice, we demonstrated that besides antibacterial action, silver nanoparticles (nAg) appear to have anti-inflammatory properties. Herein we further confirm the anti-inflammatory effects of nAg and explore their potential clinical application through a postoperative peritoneal adhesion model. We also elucidate the potential mechanism of action of silver. Our in vitro and in vivo experimental findings show that nAg are effective at decreasing inflammation in peritoneal adhesions without significant toxic effects. This study thus provides further evidence for and contributes to the understanding of the anti-inflammatory properties of nAg and may also give a novel therapeutic direction for the prevention of postoperative adhesions. PMID:19405063

  9. Silver Nanoparticle Impregnated Bio-Based Activated Carbon with Enhanced Antimicrobial Activity

    NASA Astrophysics Data System (ADS)

    Selvakumar, R.; Suriyaraj, S. P.; Jayavignesh, V.; Swaminathan, K.

    2013-08-01

    The present study involves the production of silver nanoparticles using a novel yeast strain Saccharomyces cerevisiae BU-MBT CY-1 isolated from coconut cell sap. The biological reduction of silver nitrate by the isolate was deducted at various time intervals. The yeast cells after biological silver reduction were harvested and subjected to carbonization at 400°C for 1 h and its properties were analyzed using Fourier transform infra-red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscopy. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells (CCY) did not contain any particles on its surface. The carbonized silver nanoparticles containing yeast cells (CSY) were made into bioactive emulsion and tested for its efficacy against various pathogenic Gram positive and Gram negative bacteria. The antimicrobial activity studies indicated that CSY bioactive nanoemulsion was effective against Gram negative organisms than Gram positive organism.

  10. Synthesis of monodisperse silver nanoparticles for ink-jet printed flexible electronics.

    PubMed

    Zhang, Zhiliang; Zhang, Xingye; Xin, Zhiqing; Deng, Mengmeng; Wen, Yongqiang; Song, Yanlin

    2011-10-21

    In this study, monodisperse silver nanoparticles were synthesized with a new reduction system consisting of adipoyl hydrazide and dextrose at ambient temperature. By this facile and rapid approach, high concentration monodisperse silver nanoparticles were obtained on a large scale at low protectant/AgNO(3) mass ratio which was highly beneficial to low cost and high conductivity. Based on the synthesized monodisperse silver nanoparticles, conductive inks were prepared with water, ethanol and ethylene glycol as solvents, and were expected to be more environmentally friendly. A series of electrocircuits were fabricated by ink-jet printing silver nanoparticle ink on paper substrate with a commercial printer, and they had low resistivity in the range of 9.18 × 10( - 8)-8.76 × 10( - 8) ? m after thermal treatment at 160?°C for 30 min, which was about five times that of bulk silver (1.586 × 10( - 8) ? m). Moreover, a radio frequency identification (RFID) antenna was fabricated by ink-jet printing, and 6 m wireless identification was realized after an Alien higgs-3 chip was mounted on the printed antenna by the flip-chip method. These flexible electrocircuits produced by ink-jet printing would have enormous potential for low cost electrodes and sensor devices. PMID:21937786

  11. Characterization of Silver Nanoparticles in Cell Culture Medium Containing Fetal Bovine Serum.

    PubMed

    Hansen, Ulf; Thünemann, Andreas F

    2015-06-23

    Nanoparticles are being increasingly used in consumer products worldwide, and their toxicological effects are currently being intensely debated. In vitro tests play a significant role in nanoparticle risk assessment, but reliable particle characterization in the cell culture medium with added fetal bovine serum (CCM) used in these tests is not available. As a step toward filling this gap, we report on silver ion release by silver nanoparticles and on changes in the particle radii and in their protein corona when incubated in CCM. Particles of a certified reference material, p1, and particles of a commercial silver nanoparticle material, p2, were investigated. The colloidal stability of p1 is provided by the surfactants polyethylene glycol-25 glyceryl trioleate and polyethylene glycol-20 sorbitan monolaurate, whereas p2 is stabilized by polyvinylpyrrolidone. Dialyses of p1 and p2 reveal that their silver ion release rates in CCM are much larger than in water. Particle characterization was performed with asymmetrical flow field-flow fractionation, small-angle X-ray scattering, dynamic light scattering, and electron microscopy. p1 and p2 have similar hydrodynamic radii of 15 and 16 nm, respectively. The silver core radii are 9.2 and 10.2 nm. Gel electrophoresis and subsequent peptide identification reveal that albumin is the main corona component of p1 and p2 after incubation in CCM that consists of Dulbecco's modified Eagle medium with 10% fetal bovine serum added. PMID:26018337

  12. Synthesis, characterization and in vitro effects of 7 nm alloyed silver–gold nanoparticles

    PubMed Central

    Ristig, Simon; Chernousova, Svitlana; Meyer-Zaika, Wolfgang

    2015-01-01

    Summary Alloyed silver–gold nanoparticles were prepared in nine different metal compositions with silver/gold molar ratios of ranging from 90:10 to 10:90. The one-pot synthesis in aqueous medium can easily be modified to gain control over the final particle diameter and the stabilizing agents. The purification of the particles to remove synthesis by-products (which is an important factor for subsequent in vitro experiments) was carried out by multiple ultracentrifugation steps. Characterization by transmission electron microscopy (TEM), differential centrifugal sedimentation (DCS), dynamic light scattering (DLS), UV–vis spectroscopy and atomic absorption spectroscopy (AAS) showed spherical, monodisperse, colloidally stable silver–gold nanoparticles of ?7 nm diameter with measured molar metal compositions very close to the theoretical values. The examination of the nanoparticle cytotoxicity towards HeLa cells and human mesenchymal stem cells (hMSCs) showed that the toxicity is not proportional to the silver content. Nanoparticles with a silver/gold molar composition of 80:20 showed the highest toxicity. PMID:26171298

  13. One-step synthesis of silver nanoparticles in an aqueous solution and their antibacterial activities

    NASA Astrophysics Data System (ADS)

    Zhang, Guangyu; Zhang, Feng; Morikawa, Hideaki; Chen, Yueyue

    2014-03-01

    A one-step simple synthesis of silver colloid nanoparticles with controllable sizes is presented in this research. In the synthesis, an amino-terminated hyperbranched polymer (HBP-NH2) was applied as a stabilizer and a reductant. The syntheses, performed at various initial AgNO3 concentrations (0.28-0.56 g/l) in a 2 g/l HBP-NH2 aqueous solution, produced silver colloid nanoparticles having average sizes from 3 to 30 nm with narrow size distributions. The formation of silver colloid nanoparticles was characterized by Fourier Transform Infrared Spectrophotometry (FTIR), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), UV/Visible Absorption Spectrophotometry, and X-ray Diffraction (XRD) measurements. The results indicated that both particle size and the UV absorption are strongly dependent on the initial AgNO3 concentrations. The silver colloid nanoparticles, prepared with a 0.35 g/l AgNO3 aqueous solution in the presences of 2 g/l HBP-NH2, showed good antibacterial activities against Gram-negative bacteria ( Escherichia coli) and Gram-positive bacteria ( Staphylococcus aureus). A very low concentration of nano-silver (as low as 3.0 ug/ml Ag) also gave excellent antibacterial performance.

  14. Silver nanoparticle-embedded polymersome nanocarriers for the treatment of antibiotic-resistant infections.

    PubMed

    Geilich, Benjamin M; van de Ven, Anne L; Singleton, Gloria L; Sepúlveda, Liuda J; Sridhar, Srinivas; Webster, Thomas J

    2015-02-28

    The rapidly diminishing number of effective antibiotics that can be used to treat infectious diseases and associated complications in a physician's arsenal is having a drastic impact on human health today. This study explored the development and optimization of a polymersome nanocarrier formed from a biodegradable diblock copolymer to overcome bacterial antibiotic resistance. Here, polymersomes were synthesized containing silver nanoparticles embedded in the hydrophobic compartment, and ampicillin in the hydrophilic compartment. Results showed for the first time that these silver nanoparticle-embedded polymersomes (AgPs) inhibited the growth of Escherichia coli transformed with a gene for ampicillin resistance (bla) in a dose-dependent fashion. Free ampicillin, AgPs without ampicillin, and ampicillin polymersomes without silver nanoparticles had no effect on bacterial growth. The relationship between the silver nanoparticles and ampicillin was determined to be synergistic and produced complete growth inhibition at a silver-to-ampicillin ratio of 1?:?0.64. In this manner, this study introduces a novel nanomaterial that can effectively treat problematic, antibiotic-resistant infections in an improved capacity which should be further examined for a wide range of medical applications. PMID:25628231

  15. Silver nanoparticle-embedded polymersome nanocarriers for the treatment of antibiotic-resistant infections

    NASA Astrophysics Data System (ADS)

    Geilich, Benjamin M.; van de Ven, Anne L.; Singleton, Gloria L.; Sepúlveda, Liuda J.; Sridhar, Srinivas; Webster, Thomas J.

    2015-02-01

    The rapidly diminishing number of effective antibiotics that can be used to treat infectious diseases and associated complications in a physician's arsenal is having a drastic impact on human health today. This study explored the development and optimization of a polymersome nanocarrier formed from a biodegradable diblock copolymer to overcome bacterial antibiotic resistance. Here, polymersomes were synthesized containing silver nanoparticles embedded in the hydrophobic compartment, and ampicillin in the hydrophilic compartment. Results showed for the first time that these silver nanoparticle-embedded polymersomes (AgPs) inhibited the growth of Escherichia coli transformed with a gene for ampicillin resistance (bla) in a dose-dependent fashion. Free ampicillin, AgPs without ampicillin, and ampicillin polymersomes without silver nanoparticles had no effect on bacterial growth. The relationship between the silver nanoparticles and ampicillin was determined to be synergistic and produced complete growth inhibition at a silver-to-ampicillin ratio of 1 : 0.64. In this manner, this study introduces a novel nanomaterial that can effectively treat problematic, antibiotic-resistant infections in an improved capacity which should be further examined for a wide range of medical applications.

  16. Accurate determination of silver nanoparticles in animal tissues by inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Veverková, Lenka; Hradilová, Šárka; Milde, David; Paná?ek, Aleš; Skopalová, Jana; Kvítek, Libor; Petrželová, Kamila; Zbo?il, Radek

    2014-12-01

    This study examined recoveries of silver determination in animal tissues after wet digestion by inductively coupled plasma mass spectrometry. The composition of the mineralization mixture for microwave assisted digestion was optimized and the best recoveries were obtained for mineralization with HNO3 and addition of HCl promptly after digestion. The optimization was performed on model samples of chicken meat spiked with silver nanoparticles and a solution of ionic silver. Basic calculations of theoretical distribution of Ag among various silver-containing species were implemented and the results showed that most of the silver is in the form of soluble complexes AgCl2- and AgCl32 - for the optimized composition of the mineralization mixture. Three animal tissue certified reference materials were then analyzed to verify the trueness and precision of the results.

  17. Green synthesis of water-soluble nontoxic polymeric nanocomposites containing silver nanoparticles.

    PubMed

    Prozorova, Galina F; Pozdnyakov, Alexsandr S; Kuznetsova, Nadezhda P; Korzhova, Svetlana A; Emel'yanov, Artem I; Ermakova, Tamara G; Fadeeva, Tat'yana V; Sosedova, Larisa M

    2014-01-01

    New water-soluble nontoxic nanocomposites of nanosized silver particles in a polymer matrix were synthesized by a green chemistry method. Nontoxic poly(1-vinyl-1,2,4-triazole) was used as a stabilizing precursor agent in aqueous medium. Glucose and dimethyl sulfoxide were used as the silver ion-reducing agents to yield silver nanoparticles 2-26 nm and 2-8 nm in size, respectively. The nanocomposites were characterized by transmission electron microscopy, ultraviolet-visible and Fourier transform infrared spectroscopy, X-ray diffraction, atomic absorption, and thermogravimetric data analysis. The nanocomposites showed strong antimicrobial activity against Gram-negative and Gram-positive bacteria. PMID:24790430

  18. Green synthesis of water-soluble nontoxic polymeric nanocomposites containing silver nanoparticles

    PubMed Central

    Prozorova, Galina F; Pozdnyakov, Alexsandr S; Kuznetsova, Nadezhda P; Korzhova, Svetlana A; Emel’yanov, Artem I; Ermakova, Tamara G; Fadeeva, Tat’yana V; Sosedova, Larisa M

    2014-01-01

    New water-soluble nontoxic nanocomposites of nanosized silver particles in a polymer matrix were synthesized by a green chemistry method. Nontoxic poly(1-vinyl-1,2,4-triazole) was used as a stabilizing precursor agent in aqueous medium. Glucose and dimethyl sulfoxide were used as the silver ion-reducing agents to yield silver nanoparticles 2–26 nm and 2–8 nm in size, respectively. The nanocomposites were characterized by transmission electron microscopy, ultraviolet-visible and Fourier transform infrared spectroscopy, X-ray diffraction, atomic absorption, and thermogravimetric data analysis. The nanocomposites showed strong antimicrobial activity against Gram-negative and Gram-positive bacteria. PMID:24790430

  19. Epigallocatechin-3-gallate-capped Ag nanoparticles: preparation and characterization.

    PubMed

    Hussain, Shokit; Khan, Zaheer

    2014-07-01

    We used an aqueous leaf extract of Camellia sinensis to synthesize Ag nanoparticles (AgNPs). A layer of ca. 6 nm around a group of the AgNPs in which the inner layer is bound to the AgNPs surface via the hydroxyl groups of catechin has been observed. TEM analysis of AgNPs showed the formation of truncated triangular nanoplates and/or nanodisks and spherical with some irregular-shaped polydispersed nanoparticles in absence and presence of shape-directing cetyltrimethylammonium bromide. The polyphenolic groups of epigallocatechin-3-gallate (EGCG) are responsible for the rapid reduction of Ag(+) ions into metallic Ag(0). The free -OH groups are able to stabilize AgNPs by the interaction between the surface Ag atoms of AgNPs and oxygen atoms of EGCG molecules. PMID:24297160

  20. Biosynthesis of silver nanoparticles by the seed extract of Strychnos potatorum: a natural phytocoagulant.

    PubMed

    Kora, Aruna Jyothi; Arunachalam, Jayaraman

    2013-09-01

    In this study, facile and ecofriendly methods have been developed for the biosynthesis of silver nanoparticles from silver nitrate using the seed extract of Strychnos potatorum, a natural phytocoagulant. The effect of room temperature stirring, water bath heating and autoclaving on nanoparticle synthesis was studied. The water soluble compounds in the extract serve as reducing and stabilising agents. Analytical techniques such as UV-visible spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction were used to characterise the synthesised nanoparticles. By tuning the reaction conditions, size controlled spherical nanoparticles of around 14.1 ± 4.8 nm were generated. The face centred cubic crystalline structure of the nanoparticles is confirmed from the observed peaks corresponding to (111), (200), (220) and (311) planes in the XRD pattern, concentric rings with intermittent bright dots in selected-area electron diffraction patterns and clear lattice fringes in high-resolution TEM images. With Fourier transform infrared spectroscopy and Raman spectroscopy, a probable mechanism involved in the reduction and stabilisation of nanoparticles has been investigated. As the silver nanoparticles are encapsulated with functional groups, they can be easily integrated for various biomedical applications. PMID:24028806

  1. Metal dependent catalytic hydrogenation of nitroarenes over water-soluble glutathione capped metal nanoparticles.

    PubMed

    Sharma, Sachil

    2015-03-01

    The water soluble glutathione capped metal nanoparticles (M-GS, where M=Pd, Pt, Au and Ag; GS=glutathione) with size 2.4±0.2 nm were synthesized by borohydride reduction of metal ions in the presence of glutathione as capping ligand and used as catalyst for the hydrogenation of nitroaniline in aqueous phase. The rate of catalytic hydrogenation was dependent on metal type and the trend of catalytic activity over these M-GS nanoparticles was found to be Pd-GS (k(app)=0.0227 (±3×10(-4)))s(-1)?Pt-GS (k(app)=0.0043 (±1×10(-4)))s(-1)>Au-GS (k(app)=0.0015 (±0.2×10(-4)))s(-1)>Ag-GS (k(app)=0.0008 (±0.2×10(-4)))s(-1). The similar trend of catalytic activity was found for the hydrogenation of nitrobenzene. Our experimental results, along taking into account the theoretical calculations done by other research groups, suggest that the observed catalytic activity trend is attributed to the "different rates of H2 molecule adsorption and dissociation" on the M-GS nanoparticles. The "high rate of H2 molecule adsorption" and "highly oxidized surface" make Pd-GS nanoparticles an ideal candidate for the rapid hydrogenation. On the basis of our experimental results, we proposed that small gaps between less densely packed branched thiol "glutathione molecules" provide the access to metal nanoparticle surface for the hydrogenation reaction. PMID:25485808

  2. [Toxicological sanitary characterization of silver nanoparticles introduced in gastrointestinal tract of rats].

    PubMed

    Shumakova, A A; Smirnova, V V; Tananova, O N; Trushina, ? N; Kravchenko, L V; Aksenov, I V; Selifanov, A V; Soto, S Kh; Kuznetsova, G G; Bulakhov, A V; Safenkova, I V; Gmoshinski?, I V; Khotimchenko, S A

    2011-01-01

    Water suspensions of silver nanoparticles were introduced intragastrically to growing male Wistar rats daily for 28 days. There were studied animals mass gain, relative masses of viscera, intestinal barrier resistance against protein macromolecules, DNA oxidative damage, tissue non-protein thiol levels, first and second phase of xenobiotic detoxication system activity, lysosomal membranes stability in liver together with routine blood biochemical and hematological indices and caecal's microbiocenose state. The data testifying to possible toxic risks, connected with reaction of silver's nanoparticles is obtained. PMID:22379858

  3. Surface enhanced Raman scattering study of the antioxidant alkaloid boldine using prismatic silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Herrera, M. A.; Jara, G. P.; Villarroel, R.; Aliaga, A. E.; Gómez-Jeria, J. S.; Clavijo, E.; Garrido, C.; Aguayo, T.; Campos Vallette, M. M.

    2014-12-01

    Prismatic silver nanoparticles (PNps) were used in the surface enhanced Raman scattering (SERS) study of the antioxidant alkaloid boldine (5,6,6a,7-tetrahydro-1,10-dimethoxy-6-methyl-4H-dibenzo[de,g]quinoline-2,9-diol). Prismatic and quasi-spherical (QsNps) silver nanoparticles were synthesized and characterized by UV-Vis spectra, topographic profile (AFM) and zeta potential measurements. Raman and infrared (IR) spectra of the boldine were registered. Theoretical model calculations of the boldine onto the Ag surface predict a nearly coplanar orientation of the benzo[de]quinoline moiety and non-bonded interactions (electrostatic).

  4. Anisotropy in the nonlinear absorption of elongated silver nanoparticles in silica, probed by femtosecond pulses

    NASA Astrophysics Data System (ADS)

    Rangel-Rojo, R.; McCarthy, J.; Bookey, H. T.; Kar, A. K.; Rodriguez-Fernandez, L.; Cheang-Wong, J. C.; Crespo-Sosa, A.; Lopez-Suarez, A.; Oliver, A.; Rodriguez-Iglesias, V.; Silva-Pereyra, H. G.

    2009-05-01

    We present measurements of the anisotropy of the nonlinear absorption of a silica matrix doped with aligned spheroidal silver nanoparticles, produced by a double ion-implantation process of silver nanoparticles followed by an irradiation with Si ions. The nonlinear response was studied using the z-scan technique with fs pulses at 530 nm, which lies very close to the surface-plasmon absorption peak of the sample. The observed saturable absorption is studied for different angles of the input linear polarization of the pulses, showing a strong anisotropy, which is consistent with the fact that the nanorods are aligned.

  5. The antifungal activity of corona treated polyamide and polyester fabrics loaded with silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Saponjic, Z.; Ilic, V.; Vodnik, V.; Mihailovic, D.; Jovancic, P.; Nedeljkovic, J.; Radetic, M.

    2008-07-01

    This study is aimed to highlight the possibility of using the corona treatment for fiber surface activation that can facilitate the loading of silver nanoparticles from colloids onto the polyester and polyamide fabrics and thus enhance their antifungal activity against Candida albicans. Additionally, the laundering durability of achieved effects was studied. Corona activated polyamide and polyester fabrics loaded with silver nanoparticles showed better antifungal properties compared to untreated fabrics. The positive effect of corona treatment became even more prominent after 5 washing cycles, especially for polyester fabrics.

  6. Facile green synthesis of silver nanoparticles using seed aqueous extract of Pistacia atlantica and its antibacterial activity.

    PubMed

    Sadeghi, Babak; Rostami, Amir; Momeni, S S

    2015-01-01

    In the present work, we describe the synthesis of silver nanoparticles (Ag-NPs) using seed aqueous extract of Pistacia atlantica (PA) and its antibacterial activity. UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX) were performed to ascertain the formation of Ag-NPs. It was observed that the growths of Ag-NPs are stopped within 35 min of reaction time. The synthesized Ag-NPs were characterized by a peak at 446 nm in the UV-visible spectrum. XRD confirmed the crystalline nature of the nanoparticles of 27 nm size. The XRD peaks at 38°, 44°, 64° and 77° can be indexed to the (111), (200), (220) and (311) Bragg's reflections of cubic structure of metallic silver, respectively. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. Antibacterial activities of Ag-NPs were tested against the growth of Gram-positive (S. aureus) using SEM. The inhibition was observed in the Ag-NPs against S. aureus. The results suggest that the synthesized Ag-NPs act as an effective antibacterial agent. It is confirmed that Ag-NPs are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of used drugs against bacterial diseases. The scanning electron microscopy (SEM), indicated that, the most strains of S. aureus was damaged and extensively disappeared by addition of Ag-NPs. The results confirmed that the (PA) is a very good eco friendly and nontoxic source for the synthesis of Ag-NPs as compared to the conventional chemical/physical methods. PMID:25022505

  7. Antiviral Properties of Silver Nanoparticles on a Magnetic Hybrid Colloid

    PubMed Central

    Park, SungJun; Park, Hye Hun; Kim, Sung Yeon; Kim, Su Jung; Woo, Kyoungja

    2014-01-01

    Silver nanoparticles (AgNPs) are considered to be a potentially useful tool for controlling various pathogens. However, there are concerns about the release of AgNPs into environmental media, as they may generate adverse human health and ecological effects. In this study, we developed and evaluated a novel micrometer-sized magnetic hybrid colloid (MHC) decorated with variously sized AgNPs (AgNP-MHCs). After being applied for disinfection, these particles can be easily recovered from environmental media using their magnetic properties and remain effective for inactivating viral pathogens. We evaluated the efficacy of AgNP-MHCs for inactivating bacteriophage ?X174, murine norovirus (MNV), and adenovirus serotype 2 (AdV2). These target viruses were exposed to AgNP-MHCs for 1, 3, and 6 h at 25°C and then analyzed by plaque assay and real-time TaqMan PCR. The AgNP-MHCs were exposed to a wide range of pH levels and to tap and surface water to assess their antiviral effects under different environmental conditions. Among the three types of AgNP-MHCs tested, Ag30-MHCs displayed the highest efficacy for inactivating the viruses. The ?X174 and MNV were reduced by more than 2 log10 after exposure to 4.6 × 109 Ag30-MHCs/ml for 1 h. These results indicated that the AgNP-MHCs could be used to inactivate viral pathogens with minimum chance of potential release into environment. PMID:24487537

  8. Antibacterial Effect of Silver Nanoparticles Against Four Foodborne Pathogens

    PubMed Central

    Zarei, Mehdi; Jamnejad, Amirhesam; Khajehali, Elahe

    2014-01-01

    Background: There is increased demand for improved disinfection methods due to microorganisms resistant to multiple antimicrobial agents. Numerous types of disinfectants are available with different properties; but the proper disinfectant must be carefully selected for any specific application to obtain the desired antimicrobial effect. Objectives: Antimicrobial effect of a commercial nanosilver product, NanoCid® L2000, against some foodborne pathogens was evaluated. Materials and Methods: Minimum inhibitory concentrations (MIC) were determined by monitoring the growth of bacteria at 600 nm, after 24 hours incubation at 35°C. Minimum bactericidal concentrations (MBC) were determined based on 3 log decrease in the viable population of the pathogens after incubation of nutrient agar plates at 35°C for 24 hours. The required exposure time for 3 log reduction in the viable population of the tested pathogens was determined as the minimum exposure time for efficient bactericidal activity. Results: The MIC values of Ag NPs against tested pathogens were in the range of 3.12-6.25 µg/mL. While Listeria monocytogenes showed the MIC value of 6.25 µg/mL, Escherichia coli O157:H7, Salmonella typhimurium and Vibrio parahaemolyticus all showed the MIC values of 3.12 µg/mL. However, all the pathogens showed the same MBC value of 6.25 µg/mL. To obtain an efficient bactericidal activity against E. coli O157:H7 and S. typhimurium, the exposure time should be at least ca. 6 hours., while this time was ca. 5 hours for V. parahaemolyticus and ca. 7 hours for L. monocytogenes. Conclusions: Silver nanoparticles showed great antibacterial effectiveness on four important foodborne pathogens. Therefore, Ag NPs could be a good alternative for cleaning and disinfection of equipment and surfaces in food-related environments. PMID:25147658

  9. Scolicidal activity of biosynthesized silver nanoparticles against Echinococcus granulosus protoscolices.

    PubMed

    Rahimi, Mohammad Taghi; Ahmadpour, Ehsan; Rahimi Esboei, Bahman; Spotin, Adel; Kohansal Koshki, Mohammad Hasan; Alizadeh, Ahad; Honary, Soheila; Barabadi, Hamed; Ali Mohammadi, Milad

    2015-07-01

    Cystic hydatid disease (CHD), a helminth infection with various clinical complications caused by the larval stage of the dog tapeworm Echinococcus granulosus is considered as a public health problem in different regions of the world. To date, scolicidal agents have been broadly applied for inactivation of the fertile cysts and these scolicidal agents have several side effects on patients. Therefore, the objective of this study was to evaluate the scolicidal efficacies of synthesized silver nanoparticles (AgNPs) derived from the aqueous aerial extract of Penicillium aculeatum against protoscolices of CHD in-vitro. Protoscolices were aseptically aspirated from infected livers of sheep with CHD. Various concentrations (0.025, 0.05, 0.1 and 0.15 mg/mL) of green synthesis of Ag-NPs and different exposure times (10, 30, 60 and 120 min) were used against protoscolices of CHD. Viability of protoscolices was confirmed by 0.1% eosin staining. The findings showed that the Ag-NPs at all concentrations have high scolicidal effects. The concentrations 0.1 and 0.15 mg/mL after 120 min of exposure times showed 83% and 90% mortality rate, respectively. The least scolicidal activity of biosynthesized Ag-NPs was 40% (0.025 mg/mL and 10 min). The current investigation indicated that applying biogenic Ag-NPs may be considered as a potential scolicidal agent for CHD surgery due to being economical, safer and non-toxic compared to the used chemical materials. However, further studies are required to evaluate the efficacy of Ag-NPs in vivo. PMID:26028438

  10. Biosynthesis of gold and silver nanoparticles using Emblica Officinalis fruit extract, their phase transfer and transmetallation in an organic solution.

    PubMed

    Ankamwar, Balaprasad; Damle, Chinmay; Ahmad, Absar; Sastry, Murali

    2005-10-01

    The design, synthesis and characterization of biologically synthesized nanomaterials have become an area of significant interest. In this paper, we report the extracellular synthesis of gold and silver nanoparticles using Emblica Officinalis (amla, Indian Gooseberry) fruit extract as the reducing agent to synthesize Ag and Au nanoparticles, their subsequent phase transfer to an organic solution and the transmetallation reaction of hydrophobized silver nanoparticles with hydrophobized chloroaurate ions. On treating aqueous silver sulfate and chloroauric acid solutions with Emblica Officinalis fruit extract, rapid reduction of the silver and chloroaurate ions is observed leading to the formation of highly stable silver and gold nanoparticles in solution. Transmission Electron Microscopy analysis of the silver and gold nanoparticles indicated that they ranged in size from 10 to 20 nm and 15 to 25 nm respectively. Ag and Au nanoparticles thus synthesized were then phase transferred into an organic solution using a cationic surfactant octadecylamine. Transmetallation reaction between hydrophobized silver nanoparticles and hydrophobized chloroaurate ions in chloroform resulted in the formation of gold nanoparticles. PMID:16245525

  11. Biogenesis of antibacterial silver nanoparticles using the endophytic bacterium Bacillus cereus isolated from Garcinia xanthochymus

    PubMed Central

    Sunkar, Swetha; Nachiyar, C Valli

    2012-01-01

    Objective To synthesize the ecofriendly nanoparticles, which is viewed as an alternative to the chemical method which initiated the use of microbes like bacteria and fungi in their synthesis. Methods The current study uses the endophytic bacterium Bacillus cereus isolated from the Garcinia xanthochymus to synthesize the silver nanoparticles (AgNPs). The AgNPs were synthesized by reduction of silver nitrate solution by the endophytic bacterium after incubation for 3-5 d at room temperature. The synthesis was initially observed by colour change from pale white to brown which was confirmed by UV-Vis spectroscopy. The AgNPs were further characterized using FTIR, SEM-EDX and TEM analyses. Results The synthesized nanoparticles were found to be spherical with the size in the range of 20-40 nm which showed a slight aggregation. The energy-dispersive spectra of the nanoparticle dispersion confirmed the presence of elemental silver. The AgNPs were found to have antibacterial activity against a few pathogenic bacteria like Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Klebsiella pneumoniae. Conclusions The endophytic bacteria identified as Bacillus cereus was able to synthesize silver nanoparticles with potential antibacterial activity. PMID:23593575

  12. Salinity influences on the uptake of silver nanoparticles and silver nitrate by marine medaka (Oryzias melastigma).

    PubMed

    Wang, Jian; Wang, Wen-Xiong

    2014-03-01

    With increasing use of silver nanoparticles (AgNPs), concerns about their potential deleterious effects on aquatic ecosystems have increased. Most previous studies have focused on the toxicity of AgNPs while their bioavailability has been seldom investigated. The present study examined the effects of salinity on the aggregation kinetics as well as the bioavailability of commercial 80-nm citrate-coated AgNPs (c-AgNPs) in the presence or absence of a nonionic surfactant (Tween 20) to marine medaka (Oryzias melastigma). In addition, the uptake of soluble Ag was quantified for comparison and for deducting the uptake of soluble Ag during AgNP exposure by applying a biokinetic model. The authors found that the addition of Tween 20 immediately slowed down the process of aggregation of AgNPs, and an elevated amount of Tween 20 (20 µM) kept AgNPs well dispersed, even in the 30-psu salinity medium. Uptake rate constants (ku ) of AgNPs were less than half the soluble Ag at low salinities (1 psu and 5 psu), while limited bioavailability of c-AgNPs was observed at high salinities (15 psu and 30 psu). However, the Tween 20-stabilized AgNPs (t-AgNPs) were accumulated by medaka at comparable rates as the soluble Ag, indicating the importance of dispersion for bioavailability of AgNPs in a highly ionic environment. The present study provided the first insight of the bioavailability of AgNPs to fish in a high-ionic environment. More studies are needed to gain a full understanding of bioavailability of AgNPs in marine environments. PMID:24464862

  13. Antibacterial surfaces by adsorptive binding of polyvinyl-sulphonate-stabilized silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Vasilev, Krasimir; Sah, Vasu R.; Goreham, Renee V.; Ndi, Chi; Short, Robert D.; Griesser, Hans J.

    2010-05-01

    This paper presents a novel and facile method for the generation of efficient antibacterial coatings which can be applied to practically any type of substrate. Silver nanoparticles were stabilized with an adsorbed surface layer of polyvinyl sulphonate (PVS). This steric layer provided excellent colloidal stability, preventing aggregation over periods of months. PVS-coated silver nanoparticles were bound onto amine-containing surfaces, here produced by deposition of an allylamine plasma polymer thin film onto various substrates. SEM imaging showed no aggregation upon surface binding of the nanoparticles; they were well dispersed on amine surfaces. Such nanoparticle-coated surfaces were found to be effective in preventing attachment of Staphylococcus epidermidis bacteria and also in preventing biofilm formation. Combined with the ability of plasma polymerization to apply the thin polymeric binding layer onto a wide range of materials, this method appears promising for the fabrication of a wide range of infection-resistant biomedical devices.

  14. Qualitative assessment of silver and gold nanoparticle synthesis in various plants: a photobiological approach

    Microsoft Academic Search

    Pala Rajasekharreddy; Pathipati Usha Rani; Bojja Sreedhar

    2010-01-01

    The development of rapid and ecofriendly processes for the synthesis of silver (Ag) and gold (Au) nanoparticles is of great\\u000a importance in the field of nanotechnology. In this study, the extracellular production of Ag and Au nanoparticles was carried\\u000a out from the leaves of the plants, Tridax procumbens L. (Coat buttons), Jatropa curcas L. (Barbados nut), Calotropis gigantea L. (Calotropis),

  15. Uptake and effects of manufactured silver nanoparticles in rainbow trout ( Oncorhynchus mykiss) gill cells

    Microsoft Academic Search

    Julia Farkas; Paul Christian; Julián Alberto Gallego-Urrea; Norbert Roos; Martin Hassellöv; Knut Erik Tollefsen; Kevin V. Thomas

    2011-01-01

    Nanoparticles are already widely used in technology, medicine and consumer products, but there are limited data on their effects on the aquatic environment. In this study the uptake and effect of citrate (AgNPCIT) and polyvinylpyrrolidone (AgNPPVP) coated manufactured silver nanoparticles, as well as AgNO3 (Ag+) were tested using primary gill cells of rainbow trout (Oncorhynchus mykiss). Prior to use, the

  16. Surface chemical and biological characterization of flax fabrics modified with silver nanoparticles for biomedical applications.

    PubMed

    Paladini, F; Picca, R A; Sportelli, M C; Cioffi, N; Sannino, A; Pollini, M

    2015-07-01

    Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications and wound healing. This work aims to investigate the surface chemical composition and biological properties of silver nanoparticle-modified flax substrates. Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution, by means of a large-scale apparatus. The silver-coated materials were characterized through X-ray Photoelectron Spectroscopy (XPS), to assess the surface elemental composition of the coatings, and the chemical speciation of both the substrate and the antibacterial nanophases. A detailed investigation of XPS high resolution regions outlined that silver is mainly present on nanophases' surface as Ag2O. Scanning electron microscopy and energy dispersive X-ray spectroscopy were also carried out, in order to visualize the distribution of silver particles on the fibers. The materials were also characterized from a biological point of view in terms of antibacterial capability and cytotoxicity. Agar diffusion tests and bacterial enumeration tests were performed on Gram positive and Gram negative bacteria, namely Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity tests were performed through the extract method on murine fibroblasts in order to verify if the presence of the silver coating affected the cellular viability and proliferation. Durability of the coating was also assessed, thus confirming the successful scaling up of the process, which will be therefore available for large-scale production. PMID:25953533

  17. Direct printing of silver nanoparticles by an agarose stamp on planar and patterned substrates

    NASA Astrophysics Data System (ADS)

    Kao, Yu-Chih; Hong, Franklin Chau-Nan

    2011-05-01

    In this study, we have used an agarose stamp to conduct direct printing of silver nanoparticles, nanowires and nanoplates on both planar and structured substrates. Nanoparticle solution could be first coated on an agarose stamp, and then transferred to a planar substrate. Micro-patterns comprising metal nanoparticles could be printed on planar substrates without the formation of residual layers. Thus a three-dimensional metal microstructure could be easily fabricated. The patterning of electrodes by printing Ag nanowires directly on TiO2 was also demonstrated to fabricate resistive random access memory (RRAM) devices by all-solution-processing methods. By using a flat agarose stamp, the patterns printed on the microstructured substrates were quite different from those on the nanostructured substrates. On the microstructured substrates, direct printing could print silver nanoparticles onto the protrusion surface, and could print silver layers as thick as several microns, useful for high conductivity electrodes. On the substrates with nanostructures such as photonic crystals or nano-gratings, direct printing could transfer nanoparticles into the grooves or cavities only due to the contact of the agarose stamp with the groove or concavity surface. A new approach to fabricate metal wire grid polarizers was further demonstrated. A nanoporous agarose stamp has a good potential for printing using nanoparticle suspension.

  18. Sunroot mediated synthesis and characterization of silver nanoparticles and evaluation of its antibacterial and rat splenocyte cytotoxic effects

    PubMed Central

    Aravinthan, Adithan; Govarthanan, Muthusamy; Selvam, Kandasamy; Praburaman, Loganathan; Selvankumar, Thangasamy; Balamurugan, Rangachari; Kamala-Kannan, Seralathan; Kim, Jong-Hoon

    2015-01-01

    A rapid, green phytosynthesis of silver nanoparticles (AgNPs) using the aqueous extract of Helianthus tuberosus (sunroot tuber) was reported in this study. The morphology of the AgNPs was determined by transmission electron microscopy (TEM). Scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS) and X-ray powder diffraction (XRD) analysis confirmed the presence of AgNPs. Fourier transform infrared spectroscopy (FTIR) analysis revealed that biomolecules in the tuber extract were involved in the reduction and capping of AgNPs. The energy-dispersive spectroscopy (EDS) analysis of the AgNPs, using an energy range of 2–4 keV, confirmed the presence of elemental silver without any contamination. Further, the synthesized AgNPs were evaluated against phytopathogens such as Ralstonia solanacearum and Xanthomonas axonopodis. The AgNPs (1–4 mM) extensively reduced the growth rate of the phytopathogens. In addition, the cytotoxic effect of the synthesized AgNPs was analyzed using rat splenocytes. The cell viability was decreased according to the increasing concentration of AgNPs and 67% of cell death was observed at 100 ?g/mL. PMID:25792831

  19. Sunroot mediated synthesis and characterization of silver nanoparticles and evaluation of its antibacterial and rat splenocyte cytotoxic effects.

    PubMed

    Aravinthan, Adithan; Govarthanan, Muthusamy; Selvam, Kandasamy; Praburaman, Loganathan; Selvankumar, Thangasamy; Balamurugan, Rangachari; Kamala-Kannan, Seralathan; Kim, Jong-Hoon

    2015-01-01

    A rapid, green phytosynthesis of silver nanoparticles (AgNPs) using the aqueous extract of Helianthus tuberosus (sunroot tuber) was reported in this study. The morphology of the AgNPs was determined by transmission electron microscopy (TEM). Scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and X-ray powder diffraction (XRD) analysis confirmed the presence of AgNPs. Fourier transform infrared spectroscopy (FTIR) analysis revealed that biomolecules in the tuber extract were involved in the reduction and capping of AgNPs. The energy-dispersive spectroscopy (EDS) analysis of the AgNPs, using an energy range of 2-4 keV, confirmed the presence of elemental silver without any contamination. Further, the synthesized AgNPs were evaluated against phytopathogens such as Ralstonia solanacearum and Xanthomonas axonopodis. The AgNPs (1-4 mM) extensively reduced the growth rate of the phytopathogens. In addition, the cytotoxic effect of the synthesized AgNPs was analyzed using rat splenocytes. The cell viability was decreased according to the increasing concentration of AgNPs and 67% of cell death was observed at 100 ?g/mL. PMID:25792831

  20. Growth of ordered silver nanoparticles in silica film mesostructured with a triblock copolymer PEO-PPO-PEO

    SciTech Connect

    Bois, L., E-mail: laurence.bois@univ-lyon1.f [Laboratoire Multimateriaux et Interfaces, UMR CNRS 5615, Bat Berthollet, Universite Claude Bernard Lyon 1, 43 Bd 11 nov 1918, 69622 Villeurbanne (France); Chassagneux, F.; Parola, S. [Laboratoire Multimateriaux et Interfaces, UMR CNRS 5615, Bat Berthollet, Universite Claude Bernard Lyon 1, 43 Bd 11 nov 1918, 69622 Villeurbanne (France); Bessueille, F. [Laboratoire des Sciences Analytiques, UMR CNRS 5180, Bat Raulin, Universite Claude Bernard Lyon 1, 43 Bd 11 nov 1918, 69622 Villeurbanne (France); Battie, Y.; Destouches, N.; Boukenter, A. [Laboratoire Hubert Curien, UMR 5516 - Universite Jean Monnet, 18 Rue Prof. B. Lauras, Bat F, F-42000 Saint-Etienne (France); Moncoffre, N., E-mail: n.moncoffre@ipnl.in2p3.f [Universite Lyon 1, IPNL, CNRS/IN2P3, 4 rue E. Fermi, 69622 Villeurbanne cedex (France); Toulhoat, N. [Universite Lyon 1, IPNL, CNRS/IN2P3, 4 rue E. Fermi, 69622 Villeurbanne cedex (France); CEA/DEN, Centre de Saclay, 91191 Gif sur Yvette Cedex (France)

    2009-07-15

    Elaboration of mesostructured silica films with a triblock copolymer polyethylene oxide-polypropylene oxide-polyethylene oxide, (PEO-PPO-PEO) and controlled growth of silver nanoparticles in the mesostructure are described. The films are characterized using UV-visible optical absorption spectroscopy, TEM, AFM, SEM, X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). Organized arrays of spherical silver nanoparticles with diameter between 5 and 8 nm have been obtained by NaBH{sub 4} reduction. The size and the repartition of silver nanoparticles are controlled by the film mesostructure. The localization of silver nanoparticles exclusively in the upper-side part of the silica-block copolymer film is evidenced by RBS experiment. On the other hand, by using a thermal method, 40 nm long silver sticks can be obtained, by diffusion and coalescence of spherical particles in the silica-block copolymer layer. In this case, migration of silver particles toward the glass substrate-film interface is shown by the RBS experiment. - Graphical abstract: Growth of silver nanoparticles in a mesostructured block copolymer F127-silica film is performed either by a chemical route involving NaBH{sub 4} reduction or by a thermal method. An array of spherical silver nanoparticles with 10 nm diameter on the upper-side of the mesostructured film or silver sticks long of 40 nm with a preferential orientation are obtained according to the method used. a: TEM image of the Fag5SiNB sample illustrating the silver nanoparticles array obtained by the chemical process; b: HR-TEM image of the Fag20Sid2 sample illustrating the silver nanosticks obtained by the thermal process.