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Sample records for capped silver nanoparticles

  1. Synthesis and characterization of dextran-capped silver nanoparticles with enhanced antibacterial activity.

    PubMed

    Yang, Guili; Lin, Qiuxia; Wang, Chunren; Li, Junjie; Wang, Jian; Zhou, Jin; Wang, Yan; Wang, Changyong

    2012-05-01

    Dextran-capped silver nanoparticles were synthesized by reducing silver nitrate with NaBH4 in the presence of dextran as capping agent. The characters of silver nanoparticles were investigated using UV-Vis spectrophotometer, nano-grainsize analyzer, X-ray diffraction, and transmission electron microscopy. Results showed that the silver nanoparticles capped with dextran were in uniform shape and narrow size distribution. Moreover, compared with polyvinylpyrrolidone (PVP)-capped silver nanoparticles, the dextran-capped ones possessed better stability. Antibacterial tests of these silver nanoparticles were carried out for Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Results suggested that the dextran-capped silver nanoparticles had high antibacterial activity against both Gram-positive and Gram-negative bacteria. In addition, the cytotoxicity in vitro of the dextran-capped silver nanoparticles was investigated using mouse fibrosarcoma cells (L929). The toxicity was evaluated by the changes of cell morphology and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Results indicated that these silver nanoparticles had slight effect on the survival and proliferation of L-929 cells at their minimal inhibitory concentration (MIC). After modified by dextran, the physiochemical properties of the silver nanoparticles had been improved. We anticipated that these dextran-capped silver nanoparticles could be integrated into systems for biological and pharmaceutical applications.

  2. Synthesis of water soluble glycine capped silver nanoparticles and their surface selective interaction

    SciTech Connect

    Agasti, Nityananda; Singh, Vinay K.; Kaushik, N.K.

    2015-04-15

    Highlights: • Synthesis of water soluble silver nanoparticles at ambient reaction conditions. • Glycine as stabilizing agent for silver nanoparticles. • Surface selective interaction of glycine with silver nanoparticles. • Glycine concentration influences crystalinity and optical property of silver nanoparticles. - Abstract: Synthesis of biocompatible metal nanoparticles has been an area of significant interest because of their wide range of applications. In the present study, we have successfully synthesized water soluble silver nanoparticles assisted by small amino acid glycine. The method is primarily based on reduction of AgNO{sub 3} with NaBH{sub 4} in aqueous solution under atmospheric air in the presence of glycine. UV–vis spectroscopy, transmission electron microscopy (TEM), X–ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG) and differential thermal analysis (DTA) techniques used for characterization of resulting silver nanoparticles demonstrated that, glycine is an effective capping agent to stabilize silver nanoparticles. Surface selective interaction of glycine on (1 1 1) face of silver nanoparticles has been investigated. The optical property and crystalline behavior of silver nanoparticles were found to be sensitive to concentration of glycine. X–ray diffraction studies ascertained the phase specific interaction of glycine on silver nanoparticles. Silver nanoparticles synthesized were of diameter 60 nm. We thus demonstrated an efficient synthetic method for synthesis of water soluble silver nanoparticles capped by amino acid under mild reaction conditions with excellent reproducibility.

  3. Activity of catalytic silver nanoparticles modulated by capping agent hydrophobicity.

    PubMed

    Janani, Seralathan; Stevenson, Priscilla; Veerappan, Anbazhagan

    2014-05-01

    In this paper, a facile in situ method is reported for the preparation of catalytic silver nanoparticles (AgNPs) using N-acyl tyramine (NATA) with variable hydrophobic acyl length. Scanning electron microscopic analysis shows that NATA exists initially as larger aggregates in alkaline aqueous solution. The addition of AgNO3 dissociates these larger aggregate and subsequently promotes the formation of self-assembled NATA and AgNPs. Characterization of AgNPs using UV-vis spectroscopy, scanning electron microscope and transmission electron microscope revealed that the hydrophobic acyl chain length of NATA does not influence the particle size, shape and morphology. All NATA-AgNPs yielded relatively identical values in full width at half-maximum (FWHM) analysis, indicating that the AgNPs prepared with NATA are relatively polydispersed at all tested acyl chain lengths. These nanoparticles are able to efficiently catalyze the reduction of 4-nitro phenol to 4-amino phenol, 2-nitro aniline to 1,2-diamino benzene, 2,4,6-trinitro phenol to 2,4,6-triamino phenol by NaBH4 in an aqueous environment. The reduction reaction rate is determined to be pseudo-first order and the apparent rate constant is linearly dependent on the hydrophobic acyl chain length of the NATA. All reaction kinetics presented an induction period, which is dependent on the N-acyl chain length, indicating that the hydrophobic effects play a critical role in bringing the substrate to the metal nanoparticle surface to induce the catalytic reaction. In this study, however, the five catalytic systems have similar size and polydispersity, differing only in terms of capping agent hydrophobicity, and shows different catalytic activity with respect to the alkyl chain length of the capping agent. As discussed, the ability to modulate the metal nanoparticles catalytic property, by modifying the capping agent hydrophobicity represents a promising future for developing an efficient nanocatalyst without altering the size

  4. Solid state synthesis of starch-capped silver nanoparticles.

    PubMed

    Hebeish, A; Shaheen, Th I; El-Naggar, Mehrez E

    2016-06-01

    The present research addresses the establishment of a technique which is solely devoted to environmentally friendly one-pot green synthesis of dry highly stable powdered silver nanoparticles (AgNPs) using starch as both reductant and stabilizing agent in the presence of sodium hydroxide. It is believed that the sodium hydroxide can improve the reduction potential of starch. Thus when the alkali treated starch is submitted to addition of silver nitrate (AgNO3), the alkali treated starch induces the well-established dual role of starch; reduction of silver ions (Ag(+)) to AgNPs and capping the as-formed AgNPs to prevent them from further growth and agglomeration. Beside assessment of AgNPs formation, structural and morphological characteristics of AgNPs are investigated by making use of UV-vis spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, FT-IR and X-ray diffraction (XRD) analysis. Research outputs signify (a) the absorbance around 410-420nm in the UV-vis spectra of AgNPs appears most, probably owing to the presence of nanosized silver particles and the intensity of this peak increases by increasing AgNO3 concentration; (b) that highly stable AgNPs with well-dispersed particle are successfully prepared using the present research-based innovation; (c) that the size of AgNPs does not exceed 30nm with sphere-like morphology even at the highest Ag(+) concentration employed during synthesis operation; (d) that the XRD and FT-IR confirm the successful preparation of pure AgNPs without noticeable impurities; (d) and that the one-pot synthesis of powdered AgNPs in large scale is clean and easily operated and easily transportation which may be applied as per demands of industries such as textile and painting industry.

  5. Removal of Protein Capping Enhances the Antibacterial Efficiency of Biosynthesized Silver Nanoparticles

    PubMed Central

    Jain, Navin; Bhargava, Arpit; Rathi, Mohit; Dilip, R. Venkataramana; Panwar, Jitendra

    2015-01-01

    The present study demonstrates an economical and environmental affable approach for the synthesis of “protein-capped” silver nanoparticles in aqueous solvent system. A variety of standard techniques viz. UV-visible spectroscopy, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) measurements were employed to characterize the shape, size and composition of nanoparticles. The synthesized nanoparticles were found to be homogenous, spherical, mono-dispersed and covered with multi-layered protein shell. In order to prepare bare silver nanoparticles, the protein shell was removed from biogenic nanoparticles as confirmed by UV-visible spectroscopy, FTIR and photoluminescence analysis. Subsequently, the antibacterial efficacy of protein-capped and bare silver nanoparticles was compared by bacterial growth rate and minimum inhibitory concentration assay. The results revealed that bare nanoparticles were more effective as compared to the protein-capped silver nanoparticles with varying antibacterial potential against the tested Gram positive and negative bacterial species. Mechanistic studies based on ROS generation and membrane damage suggested that protein-capped and bare silver nanoparticles demonstrate distinct mode of action. These findings were strengthened by the TEM imaging along with silver ion release measurements using inductively coupled plasma atomic emission spectroscopy (ICP-AES). In conclusion, our results illustrate that presence of protein shell on silver nanoparticles can decrease their bactericidal effects. These findings open new avenues for surface modifications of nanoparticles to modulate and enhance their functional properties. PMID:26226385

  6. Size Selective Green Synthesis of Silver and Gold Nanoparticles: Enhanced Antibacterial Efficacy of Resveratrol Capped Silver Sol.

    PubMed

    Shukla, Shashi P; Roy, Mainak; Mukherjee, Poulomi; Das, Laboni; Neogy, Suman; Srivastava, Dinesh; Adhikari, Soumyakanti

    2016-03-01

    In view of potential biomedical application of the noble metal nanoparticles, we report a size controlled yet simple and green synthesis of resveratrol stabilized silver and gold nanoparticles having low polydispersity of size. Here, resveratrol plays two simultaneous roles, reducing the metal ions and providing efficient capping of the small nanoparticles. This gives rise to specific size of silver and gold nanoparticles at specific ratios of metal to resveratrol. The particles have been characterized by XRD and transmission electron microscopy. The nanoparticle sols are stable for months. The UV Visible absorption spectra of the silver sol show the plasmon peak of spherical nanoparticles, presence of which is further reflected in the TEM images. Size of the silver particles obtained is in between 11 to 21 nm depending on the ratio of resveratrol to metal ion used. Resveratrol capped silver nanoparticles exhibit high antibacterial activity against Gram negative wild type E coli BW (25113). The minimum inhibitory concentration (MIC) of nano-silver against the bacterium has been estimated to be 6.48 μg/ml, which is significantly lower than that reported in some earlier as well as recent publications. Reaction of gold ions with resveratrol, on the other hand, produces gold nanoparticles of sizes varying from 7 to 29 nm at different ratios of resveratrol to the metal ions. Particles with higher size and aspect ratio are formed at lower concentration of the capping agent whereas particles with very small size and pseudo-spherical morphology are formed at higher capping concentration. Difference in the formation kinetics of silver and gold nanoparticles has been attributed to the different growth mechanisms in the two cases. Possible modes of anchorage of resveratrol to silver nanoparticles have been investigated using surface enhanced resonance Raman spectroscopy (SERS) which shows that the silver nanoparticles are capped by resveratrol molecule primarily through O

  7. Laser-fabricated castor oil-capped silver nanoparticles.

    PubMed

    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.

  8. 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 μg 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.

  9. γ-Cyclodextrin capped silver nanoparticles for molecular recognition and enhancement of antibacterial activity of chloramphenicol.

    PubMed

    Gannimani, Ramesh; Ramesh, Muthusamy; Mtambo, Sphamandla; Pillay, Karen; Soliman, Mahmoud E; Govender, Patrick

    2016-04-01

    Computational studies were conducted to identify the favourable formation of the inclusion complex of chloramphenicol with cyclodextrins. The results of molecular docking and molecular dynamics predicted the strongest interaction of chloramphenicol with γ-cyclodextrin. Further, the inclusion complex of chloramphenicol with γ-cyclodextrin was experimentally prepared and a phenomenon of inclusion was verified by using different characterization techniques such as thermogravimetric analysis, differential scanning calorimetry, (1)H nuclear magnetic resonance (NMR) and two dimensional nuclear overhauser effect spectroscopy (NOESY) experiments. From these results it was concluded that γ-cyclodextrins could be an appropriate cyclodextrin polymer which can be used to functionalize chloramphenicol on the surface of silver nanoparticles. In addition, γ-cyclodextrin capped silver nanoparticles were synthesized and characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR) and zeta potential analysis. Molecular recognition of chloramphenicol by these cyclodextrin capped silver nanoparticles was confirmed by surface enhanced raman spectroscopy (SERS) experiments. Synergistic antibacterial effect of chloramphenicol with γ-cyclodextrin capped silver nanoparticles was evaluated against Pseudomonas aeruginosa (ATCC 27853), Enterococcus faecalis (ATCC 5129), Klebsiella pneumoniae (ATCC 700603) and Staphylococcus aureus (ATCC 43300). The results from the antibacterial experiment were favourable thus allowing us to conclude that the approach of modifying organic drug molecules with cyclodextrin capped inorganic silver nanoparticles could help to enhance the antibacterial activity of them.

  10. The influence of the capping agent on the oxidation of silver nanoparticles: nano-impacts versus stripping voltammetry.

    PubMed

    Toh, Her Shuang; Jurkschat, Kerstin; Compton, Richard G

    2015-02-09

    The influence of capping agents on the oxidation of silver nanoparticles was studied by using the electrochemical techniques of anodic stripping voltammetry and anodic particle coulometry ("nano-impacts"). Five spherical silver nanoparticles each with a different capping agent (branched polyethylenimine (BPEI), citrate, lipoic acid, polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP)) were used to perform comparative experiments. In all cases, regardless of the capping agent, complete oxidation of the single nanoparticles was seen in anodic particle coulometry. The successful quantitative detection of the silver nanoparticle size displays the potential application of anodic particle coulometry for nanoparticle characterisation. In contrast, for anodic stripping voltammetry using nanoparticles drop casting, it was observed that the capping agent has a very significant effect on the extent of silver oxidation. All five samples gave a low oxidative charge corresponding to partial oxidation. It is concluded that the use of anodic stripping voltammetry to quantify nanoparticles is unreliable, and this is attributed to nanoparticle aggregation.

  11. Gellan gum capped silver nanoparticle dispersions and hydrogels: cytotoxicity and in vitro diffusion studies

    NASA Astrophysics Data System (ADS)

    Dhar, S.; Murawala, P.; Shiras, A.; Pokharkar, V.; Prasad, B. L. V.

    2012-01-01

    The preparation of highly stable water dispersions of silver nanoparticles using the naturally available gellan gum as a reducing and capping agent is reported. Further, exploiting the gel formation characteristic of gellan gum silver nanoparticle incorporated gels have also been prepared. The optical properties, morphology, zeta potential and long-term stability of the synthesized silver nanoparticles were investigated. The superior stability of the gellan gum-silver nanoparticle dispersions against pH variation and electrolyte addition is revealed. Finally, we studied the cytotoxicity of AgNP dispersions in mouse embryonic fibroblast cells (NIH3T3) and also evaluated the in vitro diffusion of AgNP dispersions/gels across rat skin.The preparation of highly stable water dispersions of silver nanoparticles using the naturally available gellan gum as a reducing and capping agent is reported. Further, exploiting the gel formation characteristic of gellan gum silver nanoparticle incorporated gels have also been prepared. The optical properties, morphology, zeta potential and long-term stability of the synthesized silver nanoparticles were investigated. The superior stability of the gellan gum-silver nanoparticle dispersions against pH variation and electrolyte addition is revealed. Finally, we studied the cytotoxicity of AgNP dispersions in mouse embryonic fibroblast cells (NIH3T3) and also evaluated the in vitro diffusion of AgNP dispersions/gels across rat skin. Electronic supplementary information (ESI) available: Time dependent UV-Vis spectral studies revealing the stability of AgNP dispersions and agar plate images displaying the antibacterial activity of AgNPs. See DOI: 10.1039/c1nr10957j

  12. 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...

  13. 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.

  14. Sweeter but deadlier: decoupling size, charge and capping effects in carbohydrate coated bactericidal silver nanoparticles.

    PubMed

    de Oliveira, Luciane França; Gonçalves, Julianna de Oliveira; Gonçalves, Kaliandra de Almeida; Kobarg, Jörg; Cardoso, Mateus Borba

    2013-11-01

    Silver nanoparticles are widely used due to their biomedical-antibacterial applications. At the same time, the stabilization of these nanoparticles is challenging and may be made using polymeric carbohydrates, based on the practice of avoiding toxic chemicals and undesirable residues. In this study, we synthesized silver nanoparticles (AgNPs) which were stabilized by carbohydrates (potato starch and chitosan) and characterized by UV-Vis spectroscopy, zeta potential and transmission electron microscopy techniques. Bactericidal efficiency of AgNPs capped with different carbohydrates was tested demonstrating that the synthesized materials were able to inhibit the growth of two clinical/medical relevant bacteria strains (Escherichia coil and Staphylococcus aureus). AgNPs stabilized by chitosan presented enhanced bactericidal activity if compared to the ones synthesized in presence of potato starch. This difference is mainly attributed to the known antibacterial properties of chitosan associated to overall positive charge of the nanoparticles capped by this polymer. Those nanoparticles obtained in presence of starch presented minor bactericidal effects since the starch-capping agent is not able to contribute to the avoidance of bacteria growth and confers a quasi-neutral charge to the nanoparticle.

  15. Production of putrescine-capped stable silver nanoparticle: its characterization and antibacterial activity against multidrug-resistant bacterial strains

    NASA Astrophysics Data System (ADS)

    Saha, Saswati; Gupta, Bhaskar; Gupta, Kamala; Chaudhuri, Mahua Ghosh

    2016-11-01

    Integration of biology with nanotechnology is now becoming attention-grabbing area of research. The antimicrobial potency of silver has been eminent from antiquity. Due to the recent desire for the enhancement of antibacterial efficacy of silver, various synthesis methods of silver in their nano dimensions are being practiced using a range of capping material. The present work highlights a facile biomimetic approach for production of silver nanoparticle being capped and stabilized by putrescine, possessing a diameter of 10-25 ± 1.5 nm. The synthesized nanoparticles have been analyzed spectrally and analytically. Morphological studies are carried out by high-resolution transmission electron microscopy and crystallinity by selected area electron diffraction patterns. Moreover, the elemental composition of the capped nanoparticles was confirmed by energy-dispersive X-ray spectroscopy analysis. A comparative study (zone of inhibition and minimum inhibitory concentration) regarding the interactions and antibacterial potentiality of the capped silver nanoparticles with respect to the bare ones reveal the efficiency of the capped one over the bare one. The bacterial kinetic study was executed to monitor the interference of nanoparticles with bacterial growth rate. The results also highlight the efficacy of putrescine-capped silver nanoparticles as effective growth inhibitors against multi-drug resistant human pathogenic bacterial strains, which may, thus, potentially be applicable as an effective antibacterial control system to fight diseases.

  16. Immobilization of horseradish peroxidase on β-cyclodextrin-capped silver nanoparticles: Its future aspects in biosensor application.

    PubMed

    Karim, Zoheb; Khan, Mohd Jahir; Maskat, Mohamad Yusof; Adnan, Rohana

    2016-05-18

    This study aimed to work out a simple and high-yield procedure for the immobilization of horseradish peroxidase on silver nanoparticle. Ultraviolet-visible (UV-vis) and Fourier-transform infrared spectroscopy and transmission electron microscopy were used to characterize silver nanoparticles. Horseradish peroxidase was immobilized on β-cyclodextrin-capped silver nanoparticles via glutaraldehyde cross-linking. Single-cell gel electrophoresis (Comet assay) was also performed to confirm the genotoxicity of silver nanoparticles. To decrease toxicity, silver nanoparticles were capped with β-cyclodextrin. A comparative stability study of soluble and immobilized enzyme preparations was investigated against pH, temperature, and chaotropic agent, urea. The results showed that the cross-linked peroxidase was significantly more stable as compared to the soluble counterpart. The immobilized enzyme exhibited stable enzyme activities after repeated uses.

  17. TOPO-capped silver selenide nanoparticles and their incorporation into polymer nanofibers using electrospinning technique

    SciTech Connect

    More, D.S.; Moloto, M.J.; Moloto, N.; Matabola, K.P.

    2015-05-15

    Highlights: • Ag{sub 2}Se nanoparticles produced spherical particles with sizes 12 nm (180 °C) and 27 nm (200 °C). • Higher temperature produced increased particle size (∼75 nm) and changed in shape. • Ag{sub 2}Se nanoparticles (0.2–0.6%) added into PVP (35–45%) to yield reduced fiber beading. • Polymer nanofibers electrospun at 11–20 kV produced fiber diameters of 425–461 nm. • Optical properties in the fibers were observed due to the Ag{sub 2}Se nanoparticles loaded. - Abstract: Electrospinning is the most common technique for fabricating polymer fibers as well as nanoparticles embedded polymer fibers. Silver selenide nanoparticles were synthesized using tri-n-octylphosphine (TOP) as solvent and tri-n-octylphosphine oxide (TOPO) as capping environment. Silver selenide was prepared by reacting silver nitrate and selenium with tri-n-octylphosphine (TOP) to form TOP–Ag and TOP–Se solutions. Both absorption and emission spectra signify the formation of nanoparticles as well as the TEM which revealed spherical particles with an average particle size of 22 nm. The polymer, PVP used was prepared at concentrations ranging from (35 to 45 wt%) and the TOPO-capped silver selenide nanoparticles (0.2 and 0.6 wt%) were incorporated into them and electrospun by varying the voltage from 11 to 20 kV. The SEM images of the Ag{sub 2}Se/PVP composite fibers revealed the fibers of diameters with average values of 425 and 461 nm. The X-ray diffraction results show peaks which were identified due to α-Ag{sub 2}Se body centered cubic compound. The sharp peak observed for all the samples at 2θ = 44.5 suggest the presence of Ag in the face centered cubic which can be attributed to higher concentration of silver nitrate used with molar ratio of selenium to silver and the abundance of silver in the silver selenide crystal. Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) and ultraviolet–visible spectroscopy were used to characterize the

  18. Effect of pH and biological media on polyvinylpyrrolidone-capped silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Lau, Chew Ping; Abdul-Wahab, Mohd Firdaus; Jaafar, Jafariah; Chan, Giek Far; Rashid, Noor Aini Abdul

    2016-07-01

    Toxicity and mobility of silver nanoparticles (AgNPs) vary in different surrounding environments. Surface coatings or functionalization, temperature, pH, dissolved oxygen concentration, nanoparticle concentration, the presence of organic matter, and ionic strength are factors which dictate the transformation of AgNPs in terms of aggregation and stabilization. Thus, the purpose of this study is to investigate the behavior of polyvinylpyrrolidone (PVP)-capped AgNPs at different pHs (pH 2 to 10) and in different biological media (0.1 M phosphate buffer, nutrient broth, P5 and modified P5 media) analyzed using UV-Vis spectroscopy and zeta potential analyzer. The PVP-capped AgNPs changed its behavior in the presence of varying media, after 24 h incubation with shaking at 200 rpm at 30°C. No aggregation was observed at pH 4 to 10, but distinctive at very low pH of 2. Low pH further destabilized PVP-capped AgNPs after 24 h of incubation. High ionic strength 0.1 M phosphate buffer also resulted in slow aggregation and eventually destabilized the nanoparticles. Biological media (nutrient broth, P5 and modified P5 media) containing organic components caused aggregation of the PVP-capped AgNPs. The increase in glucose and nutrient broth concentrations led to increased aggregation. However, PVP-capped AgNPs stabilized after 24 h incubation in media containing a high concentration of glucose and nutrient broth. The results demonstrate that low pH value, high ionic strength and the content of the biological media can influence the stability of AgNPs. This provides information on the aggregation behavior of PVP-capped AgNPs and can possibly further predict the fate, transport as well as the toxicity of silver nanoparticles after being released into the aquatic environment.

  19. 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.

  20. 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.

  1. Potent antimicrobial activity of bone cement encapsulating silver nanoparticles capped with oleic acid.

    PubMed

    Prokopovich, Polina; Köbrick, Mathias; Brousseau, Emmanuel; Perni, Stefano

    2015-02-01

    Bone cement is widely used in surgical treatments for the fixation for orthopaedic devices. Subsequently, 2-3% of patients undergoing these procedures develop infections that are both a major health risk for patients and a cost for the health service providers; this is also aggravated by the fact that antibiotics are losing efficacy because of the rising resistance of microorganisms to these substances. In this study, oleic acid capped silver nanoparticles (NP) were encapsulated into Poly(methyl methacrylate) (PMMA)-based bone cement samples at various ratios. Antimicrobial activity against Methicillin Resistant Staphylococcus aureus, S. aureus, Staphylococcus epidermidis, Acinetobacter baumannii was exhibited at NP concentrations as low as 0.05% (w/w). Furthermore, the mechanical properties and cytotoxicity of the bone cement containing these NP were assessed to guarantee that such material is safe to be used in orthopaedic surgical practice.

  2. Influence of pH on the properties of PVA capped silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Ajitha, B.; Reddy, P. Sreedhara

    2013-06-01

    Silver nanoparticles were synthesized by chemical reduction method using ascorbic acid as reductant and PVA as surfactant and studied the pH influence on the structural, compositional and optical properties of silver nanoparticles. Broadened XRD peaks confirmed the formation of small nanosized silver nanoparticles with face centered cubic (FCC) structure. The particle size decreased with increasing pH value. We have observed blue shift of Surface Plasmon Resonance (SPR) band from optical absorption spectra. The obtained nanoparticles were well dispersed in water, ethanol and polar solvents and thus more suitable for biocompatible.

  3. Glucose capped silver nanoparticles induce cell cycle arrest in HeLa cells.

    PubMed

    Panzarini, Elisa; Mariano, Stefania; Vergallo, Cristian; Carata, Elisabetta; Fimia, Gian Maria; Mura, Francesco; Rossi, Marco; Vergaro, Viviana; Ciccarella, Giuseppe; Corazzari, Marco; Dini, Luciana

    2017-02-20

    This study aims to determine the interaction (uptake and biological effects on cell viability and cell cycle progression) of glucose capped silver nanoparticles (AgNPs-G) on human epithelioid cervix carcinoma (HeLa) cells, in relation to amount, 2×10(3) or 2×10(4) NPs/cell, and exposure time, up to 48h. The spherical and well dispersed AgNPs (30±5nm) were obtained by using glucose as reducing agent in a green synthesis method that ensures to stabilize AgNPs avoiding cytotoxic soluble silver ions Ag(+) release. HeLa cells take up abundantly and rapidly AgNPs-G resulting toxic to cells in amount and incubation time dependent manner. HeLa cells were arrested at S and G2/M phases of the cell cycle and subG1 population increased when incubated with 2×10(4) AgNPs-G/cell. Mitotic index decreased accordingly. The dissolution experiments demonstrated that the observed effects were due only to AgNPs-G since glucose capping prevents Ag(+) release. The AgNPs-G influence on HeLa cells viability and cell cycle progression suggest that AgNPs-G, alone or in combination with chemotherapeutics, may be exploited for the development of novel antiproliferative treatment in cancer therapy. However, the possible influence of the cell cycle on cellular uptake of AgNPs-G and the mechanism of AgNPs entry in cells need further investigation.

  4. Electrochemistry of ATP-capped silver nanoparticles in layer-by-layer multilayer films

    NASA Astrophysics Data System (ADS)

    Singh, Poonam; Solomon, Virgil C.; Buttry, Daniel A.

    2014-07-01

    Colloidal silver nanoparticles (Ag NPs) capped with adenosine triphosphate (ATP) were prepared using borohydride reduction of Ag+ in the presence of ATP. Subsequent characterization was done using transmission electron microscopy/high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and non-contact atomic force microscopy (NcAFM) confirming the size and composition of the Ag NPs. This report focuses on two topics: (1) the change in NP size and properties as a function of molar ratios of Ag+ to ATP capping ligand to BH4 - reductant, and (2) the electrochemical behavior of the NPs in layer-by-layer (LbL) multilayer films. On the basis of electrostatic interaction between negatively charged phosphate groups on Ag NPs and positively charged poly(diallyldimethylammonium) hydrochloride, NPs were immobilized on 3-mercaptopropionic acid (MCP)-functionalized gold electrodes using LbL assembly method followed by characterization of the film using NcAFM. Furthermore, the redox chemistry for phase transformations of immobilized Ag NPs to AgCl or Ag2O in multilayer films was examined using cyclic voltammetry (CV) in NaOH and NaCl solutions. A non-linear increase of charge with an increase in the number of bilayers in the film was observed up to five layers. Underpotential deposition of Pb on multilayer film of Ag NPs confirmed the presence of Ag in multilayer films. The stability of the LbL film toward electrochemical cycling to higher potentials (i.e., +0.8 V) in NaOH solutions was evaluated.

  5. Antimicrobial activity of electrospun poly(butylenes succinate) fiber mats containing PVP-capped silver nanoparticles.

    PubMed

    Tian, Ligang; Wang, Pingli; Zhao, Zhiguo; Ji, Junhui

    2013-12-01

    In this study, biodegradable poly(butylenes succinate) (PBS) fiber mats containing silver nanoparticles (AgNPs) were prepared by the electrospinning process. Small AgNPs (<10 nm) were simply synthesized using polyvinylpyrrolidone as the capping agent as well as the reductant. The morphology of the PBS-AgNPs fiber mats and the distribution of the AgNPs were well characterized by TEM and SEM. The release of Ag from the PBS fiber mats was quantitively determined by ICP. The PBS fiber mats with 0.29 % AgNPs content showed strong antimicrobial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli with the efficacy as high as 99 %. The effective bactericidal activity on E. coli was demonstrated for a short contacting time with the PBS-AgNPs fiber mats. In addition, the long-term release performance of Ag from the fiber mats can keep inhibiting the bacterial growth in the mats over a long period of time.

  6. A new, simple, green, and one-pot four-component synthesis of bare and poly(α,γ, L-glutamic acid)-capped silver nanoparticles

    PubMed Central

    Savanović, Igor; Uskoković, Vuk; Škapin, Srečo D.; Bračko, Ines; Jovanović, Uroš; Uskoković, Dragan

    2013-01-01

    A simple and green chemical method has been developed to synthesize stable bare and capped silver nanoparticles based on the reduction of silver ions by glucose and capping by poly(α,γ,L-glutamic acid) (PGA). The use of ammonia during synthesis was avoided. PGA has had a dual role in the synthesis and was used as a capping agent to make the silver nanoparticle more biocompatible and to protect the nanoparticles from agglomerating in the liquid medium. The synthesized PGA-capped silver nanoparticles in the size range 5–45 nm were stable over long periods of time, without signs of precipitation. Morphological examination has shown that the silver nanoparticles had a nearly spherical, multiply twinned structure. The effects of the reaction temperature and the reaction time during the synthesis were investigated too. The biocompatibility of the PGA-capped silver nano-particles is discussed in terms of in vitro toxicity with human intestinal Caco-2 cells. The samples were characterized by UV–Visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurements. PMID:24062597

  7. 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

  8. Enhancement of antibacterial activity of capped silver nanoparticles in combination with antibiotics, on model gram-negative and gram-positive bacteria.

    PubMed

    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.

  9. Biopolymer capped silver nanoparticles as fluorophore for ultrasensitive and selective determination of malathion.

    PubMed

    Vasimalai, N; Abraham John, S

    2013-10-15

    This paper describes a novel luminescent sensor for malathion using chitosan capped silver nanoparticles (Chi-AgNPs) as fluorophore. The Chi-AgNPs were synthesized by the wet-chemical method and were characterized by absorption, fluorescence, HR-TEM, XRD and DLS techniques. The Chi-AgNPs show the absorption maximum at 394 nm and emission maximum at 536 nm. While adding 10 µM malathion, yellow color Chi-AgNPs was changed to brown and the absorbance was decreased along with a redshift. The observed spectral and color changes were mainly due to the aggregation of Chi-AgNPs. This was confirmed by zeta potential, DLS and HR-TEM studies. No significant absorption spectral change was observed for Chi-AgNPs in the presence of less than micromolar concentrations of malathion. However, the emission intensity of Chi-AgNPs was decreased and the emission maximum was shifted toward higher wavelength in the presence of picomolar concentration of malathion. Based on the decrease in emission intensity, the concentration of malathion was determined. The Stern-Volmer constant, Gibbs free energy change, association constant, quantum yield and binding constant were calculated and the quenching mechanism was proposed. The Chi-AgNPs show good selectivity toward the determination of 10nM malathion in the presence of 1000-fold higher concentrations of common interferents. A good linearity was observed for the emission intensity against 1 × 10(-9)-10 × 10(-12)M malathion and the detection limit was found to be 94 fM L(-1) (S/N=3). The proposed method was successfully applied to determine malathion in fruits and water samples and the obtained results were validated with HPLC.

  10. Green synthesis of protein capped silver nanoparticles from phytopathogenic fungus Macrophomina phaseolina (Tassi) Goid with antimicrobial properties against multidrug-resistant bacteria

    NASA Astrophysics Data System (ADS)

    Chowdhury, Supriyo; Basu, Arpita; Kundu, Surekha

    2014-07-01

    In recent years, green synthesis of nanoparticles, i.e., synthesizing nanoparticles using biological sources like bacteria, algae, fungus, or plant extracts have attracted much attention due to its environment-friendly and economic aspects. The present study demonstrates an eco-friendly and low-cost method of biosynthesis of silver nanoparticles using cell-free filtrate of phytopathogenic fungus Macrophomina phaseolina. UV-visible spectrum showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) revealed the presence of spherical silver nanoparticles of the size range 5 to 40 nm, most of these being 16 to 20 nm in diameter. X-ray diffraction (XRD) spectrum of the nanoparticles exhibited 2 θ values corresponding to silver nanoparticles. These nanoparticles were found to be naturally protein coated. SDS-PAGE analysis showed the presence of an 85-kDa protein band responsible for capping and stabilization of the silver nanoparticles. Antimicrobial activities of the silver nanoparticles against human as well as plant pathogenic multidrug-resistant bacteria were assayed. The particles showed inhibitory effect on the growth kinetics of human and plant bacteria. Furthermore, the genotoxic potential of the silver nanoparticles with increasing concentrations was evaluated by DNA fragmentation studies using plasmid DNA.

  11. Fabrication of collagen scaffolds impregnated with sago starch capped silver nanoparticles suitable for biomedical applications and their physicochemical studies.

    PubMed

    Mandal, Abhishek; Sekar, Santhanam; Seeni Meera, Kamal Mohamed; Mukherjee, Amitava; Sastry, Thotapalli P; Mandal, Asit Baran

    2014-10-07

    The present investigation attempts at fabricating collagen-based scaffolds impregnated with sago starch capped silver nanoparticles (AgNPs), useful for biomedical applications, and aims at studying their physicochemical aspects. AgNPs synthesized through a chemical reduction method, capped using different concentrations of sago starch, are incorporated into collagen derived from fish scales, and lyophilized to form scaffolds. FT-IR spectra confirm and validate the interaction of sago starch capped AgNPs with collagen in the scaffolds. TGA and DSC results indicate enhanced thermal stability of collagen scaffolds impregnated with sago capped AgNPs compared to collagen alone. All the collagen scaffolds containing sago starch capped AgNPs show high tensile strength values for their use as wound dressing materials. Moreover, lower minimum inhibitory concentration values are obtained for the above capped AgNP collagen scaffolds, which indicate higher antibacterial activities compared to uncapped AgNPs tested against both gram positive and negative bacterial strains. The novelty is that the developed scaffolds are biodegradable and in vitro studies reveal them as biocompatible and suitable for tissue regeneration applications.

  12. One-pot synthesis of PVA-capped silver nanoparticles their characterization and biomedical application

    NASA Astrophysics Data System (ADS)

    Patil, Rupali S.; Kokate, Mangesh R.; Jambhale, Chitra L.; Pawar, Sambhaji M.; Han, Sung H.; Kolekar, Sanjay S.

    2012-03-01

    The rapid one-pot synthesis of silver nanoparticles (SNPs) at room temperature by using hydrazine hydrate as reducing agent and polyvinyl alcohol as stabilizing agent is reported. The SNPs were characterized with UV-visible (UV-Vis) spectroscopy, x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The synthesized silver nanoparticle shows surface plasmon resonance at 410 nm. The XRD reveals face-centered cubic (FCC) structure of SNPs. FE-SEM, AFM and TEM show that nanoparticles have spherical morphology with diameters in the range of 10-60 nm. The antimicrobial activity of synthesized hybrid material against strains of four different bacteria (Bacillus cereus, Escherichia coli, Staphylococus aureus, Proteus vulgaris), that are commonly found in hospitals has been studied. The results indicate that such particles have potential applications in biotechnology and biomedical science.

  13. Investigations of UV photolysis of PVP-capped silver nanoparticles in the presence and absence of dissolved organic carbon

    NASA Astrophysics Data System (ADS)

    Poda, Aimee R.; Kennedy, Alan J.; Cuddy, Michael F.; Bednar, Anthony J.

    2013-05-01

    This study investigated the effect of UV irradiation on the characteristics and toxicity of 50 nm (nominal diameter) polyvinylpyrrolidone-capped silver nanoparticles (AgNPs) in the presence and absence of dissolved organic carbon (DOC). The photolysis resulted in a decrease in average particle size as measured by field flow fractionation interfaced with inductively coupled plasma mass spectrometry. The decrease in size was attributed to the photo-induced oxidation of the PVP and dissolution of metallic silver. Moreover, photolysis of the AgNPs in solutions containing DOC appeared to give rise to small nanoparticles ( 5 nm) formed via reduction of dissolved silver ions. These results were consistent with photolysis of AgNO3 solutions initially devoid of nanoparticles. Thus, the carbon-containing constituents of DOC serve as reducing agents for Ag+, primarily under conditions of UV irradiation. The standard zooplankton model, Daphnia magna, indicated that the toxicity of nanosilver was significantly reduced when the AgNPs have been exposed to UV light. Observed toxicity was further reduced when AgNPs in DOC-containing solutions were exposed to UV. These results suggest that environmentally relevant conditions such as DOC and UV light are important mitigating factors that mediate the aquatic toxicity of AgNPs.

  14. Effect of poly-α, γ, L-glutamic acid as a capping agent on morphology and oxidative stress-dependent toxicity of silver nanoparticles

    PubMed Central

    Stevanović, Magdalena; Kovačević, Branimir; Petković, Jana; Filipič, Metka; Uskoković, Dragan

    2011-01-01

    Highly stable dispersions of nanosized silver particles were synthesized using a straightforward, cost-effective, and ecofriendly method. Nontoxic glucose was utilized as a reducing agent and poly-α, γ, L-glutamic acid (PGA), a naturally occurring anionic polymer, was used as a capping agent to protect the silver nanoparticles from agglomeration and render them biocompatible. Use of ammonia during synthesis was avoided. Our study clearly demonstrates how the concentration of the capping agent plays a major role in determining the dimensions, morphology, and stability, as well as toxicity of a silver colloidal solution. Hence, proper optimization is necessary to develop silver colloids of narrow size distribution. The samples were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurement. MTT assay results indicated good biocompatibility of the PGA-capped silver nanoparticles. Formation of intracellular reactive oxygen species was measured spectrophotometrically using 2,7-dichlorofluorescein diacetate as a fluorescent probe, and it was shown that the PGA-capped silver nanoparticles did not induce intracellular formation of reactive oxygen species. PMID:22131829

  15. Effect of capping agents on the cytotoxicity of silver nanoparticles in human normal and cancer skin cell lines

    NASA Astrophysics Data System (ADS)

    Netchareonsirisuk, Ponsawan; Puthong, Songchan; Dubas, Stephan; Palaga, Tanapat; Komolpis, Kittinan

    2016-11-01

    Silver nanoparticles (AgNPs) are among the most widely used nanomaterials in medical and consumer products. However, safety in the uses of AgNPs is still controversial. The toxicity of AgNPs toward various cell types has been reported to depend on the surface properties of the nanoparticles. In this study, the effect of AgNPs with the average size of 5-15 nm on the viability of the CCD-986SK human normal skin fibroblast cell line and A375 human malignant melanoma cell line was evaluated. Comparative toxicity studies, based on MTT assay, were performed by using either sodium alginate or poly (4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA) as capping agent in the nanoparticle preparation. The cytotoxicity tests revealed that AgNO3 alone was highly toxic to both cell types while both alginate and PSSMA alone were not toxic. AgNPs capped with alginate were selectively toxic to the cancer cell line but not to the normal cell line while AgNPs capped with PSSMA were toxic to both cancer and normal cell lines. Judging from the 50 % inhibition concentration (IC50), it was found that the cancer cell line was more sensitive to AgNPs than the normal cell line. Study on the mode of cell death by annexin V and propidium iodide staining revealed that AgNPs induced more apoptotic cell death (84-90 %) than necrosis (8-12 %) in the skin cancer cell line. These results suggest that the toxicity of AgNPs depended on the type of capping agent and the type of cell line.

  16. The silver ions contribution into the cytotoxic activity of silver and silver halides nanoparticles

    NASA Astrophysics Data System (ADS)

    Klimov, A. I.; Zherebin, P. M.; Gusev, A. A.; Kudrinskiy, A. A.; Krutyakov, Y. A.

    2015-11-01

    The biocidal action of silver nanoparticles capped with sodium citrate and silver halides nanoparticles capped with non-ionic surfactant polyoxyethylene(20)sorbitan monooleate (Tween 80®) against yeast cells Saccharomyces cerevisiae was compared to the effect produced by silver nitrate and studied through the measurement of cell loss and kinetics of K+ efflux from the cells. The cytotoxicity of the obtained colloids was strongly correlated with silver ion content in the dispersions. The results clearly indicated that silver and silver halides nanoparticles destroyed yeast cells through the intermediate producing of silver ions either by dissolving of salts or by oxidation of silver.

  17. Storage Wars: how citrate-capped silver nanoparticle suspensions are affected by not-so-trivial decisions

    NASA Astrophysics Data System (ADS)

    Gorham, Justin M.; Rohlfing, Anne B.; Lippa, Katrice A.; MacCuspie, Robert I.; Hemmati, Amy; David Holbrook, R.

    2014-04-01

    A critical but often overlooked component of silver nanoparticle (AgNP) suspensions involves their behavior following short- and long-term storage. The current study investigates the integrity of citrate-capped AgNP suspensions, nominally 20 nm in average diameter, in a series of distinct storage conditions, based on possible combinations of reasonable decisions researchers make, both nanoparticle-based (AgNP and relative citrate concentration) and environmental-based (solution oxygenation and ambient light or dark). AgNP integrity was determined by monitoring single particle stability, aggregation/agglomeration, and oxidation for 104 days. We demonstrate that AgNP suspensions lose their physical and chemical integrity by two distinct processes: (1) oxidation only (light-independent) and (2) oxidation followed by photo-reduction (light-dependent), following initial dilution from a concentrated (and newly synthesized) AgNP stock solution. Optical spectroscopy indicates that the effects of oxidation are readily observed while the effects of photo-reduction are less obvious, leading to a greater increase in average particle diameter, the formation of new, metallic nanoparticles, and the oxidation of the parent citrate capping agent. In general, the overall integrity of citrate-capped AgNP suspensions are best maintained when these solutions are purged with nitrogen gas and stored in the dark at the highest AgNP and citrate concentrations. This study outlines a strategy for both assessing and monitoring the integrity of AgNP suspensions in an effort to harmonize long-term experiments and promote inter-laboratory consistency.

  18. Antibacterial potential of a small peptide from Bacillus sp. RPT-0001 and its capping for green synthesis of silver nanoparticles.

    PubMed

    Patil, Supriya Deepak; Sharma, Rajnikant; Bhattacharyya, Tapas; Kumar, Piyush; Gupta, Manasi; Chaddha, Bhupinder Singh; Navani, Naveen Kumar; Pathania, Ranjana

    2015-09-01

    Infirmity and death from diseases caused by unsafe food are a continual hazard to communal health safety and socio-economic growth throughout the world. Chemical preservatives are associated with health hazards and toxicity issues. In the study reported here, 200 soil isolates from Western Himalayan region in India were screened for potential antibacterial activity against food-borne pathogens. This study led to the isolation of a bacterial strain belonging to the Genus Bacillus and was designated as RPT-0001. The associated antibacterial activity was sensitive to pronase E treatment. Bioassay-guided fractionation using reverse phase high performance liquid chromatography (RP-HPLC) led to isolation of the antibacterial peptide designated as RPT-0001. The molecular weight of RPT-0001 was determined by electro-spray ionization mass spectroscopy (ESI-MS) as 276.9 Da. RPT-0001 was inhibitory to both Gram-negative and Grampositive food-borne bacteria tested. The characteristics of RPT-0001 do not match with that of any other known antibacterial peptides produced by Bacillus sp. or related genera. Purified RPT-0001 was successfully used in synthesis of silver nanoparticles effective against food-borne pathogenic bacteria. The antibacterial peptide and silver nanoparticles synthesized utilizing it as a capping and reducing agent hold promising potential in food preservation, in packaging material and as a therapeutic agent in the treatment of foodborne infections.

  19. Microwave Synthesis of Chitosan Capped Silver-Dysprosium Bimetallic Nanoparticles: A Potential Nanotheranosis Device.

    PubMed

    Mishra, Sandeep K; Kannan, S

    2016-12-27

    Accurate imaging of the structural and functional state of biological targets is a critical task. To amend paucities associated with individual imaging, there is high interest to develop a multifunctional theranostic devices for cancer diagnosis and therapy. Herein, chitosan coated silver/dysprosium bimetallic nanoparticles (BNPs) were synthesized through a green chemistry route and characterization results inferred that the BNPs are crystalline, spherical, and of size ∼10 nm. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray photoelectron spectroscopy (XPS) confirm the reduced metallic states of Ag and Dy in nanoparticles. These BNPs demonstrate high emission in a second near-infrared (NIR-II, 1000-1400 nm) biological window on excitation at 808 nm. Moreover, magnetization and magnetic resonance imaging (MRI) studies perceive the inherent paramagnetic features of Dy component that displays dark T2 contrast and high relaxivity. Due to high X-ray attenuation effect, BNPs exhibit better Hounsfield unit (HU) value than the reported contrast agents. BNPs unveil good biocompatibility and also express sturdy therapeutic effect in HeLa cells when tethered with doxorubicin.

  20. 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 μg/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 μg/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 μg/L of Ag-NPs. This study provides new evidence about the effects of nanoparticles on aquatic organisms. PMID:23093839

  1. A rapid method to estimate the concentration of citrate capped silver nanoparticles from UV-visible light spectra.

    PubMed

    Paramelle, D; Sadovoy, A; Gorelik, S; Free, P; Hobley, J; Fernig, D G

    2014-10-07

    We present a generalized table of extinction coefficient data for silver nanoparticles from 8 to 100 nm. This table allows for easy and quick estimation of the concentration and size of modified and mono-dispersed silver nanoparticles from their optical spectra. We obtained data by determining the silver content of citrate-stabilised silver nanoparticles using sodium cyanide to dissolve the nanoparticles, and measuring solution conductivity with a pH meter and a cyanide-ion selective electrode. The quantification of the silver ion concentration enabled the calculation of extinction coefficients. Experimentally calculated extinction coefficients, in the current work, are in good agreement with collated literature values measured by different authors with non-standardized methodology and each for a limited range of particle size. They are also in good agreement with our theoretical calculations using Mie theory. Thus, we provide a highly standardized and comprehensive tabulated reference data-set.

  2. Effects from Filtration, Capping Agents, and Presence/Absence of Food on the Toxicity of Silver Nanoparticles to Daphnia Magna

    EPA Science Inventory

    Relatively little is known regarding the behavior and toxicity of nanoparticles in the environment. The objectives of the work presented here include establishing the toxicity of a variety of silver nanoparticles (AgNPs) to Daphnia magna neonates, assessing the applicability of ...

  3. Green synthesis of silver and gold nanoparticles employing levan, a biopolymer from Acetobacter xylinum NCIM 2526, as a reducing agent and capping agent.

    PubMed

    Ahmed, Khan Behlol Ayaz; Kalla, Divya; Uppuluri, Kiran Babu; Anbazhagan, Veerappan

    2014-11-04

    With a vision of finding greener materials to synthesize nanoparticles, we report the production and isolation of levan, a polysaccharide with repeating units of fructose, from Acetobacter xylinum NCIM2526. The isolated levan were characterized using potassium ferricyanide reducing power assay, Fourier transform infra-red (FTIR) spectroscopy and (1)H nuclear magnetic resonance spectroscopy ((1)H NMR). To exploit levan in nanotechnology, we present a simple and greener method to synthesize silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using biopolymer, levan as both reducing and stabilizing agents. The morphology and stability of the AgNPs and AuNPs were examined by transmission electron microscopy (TEM) and UV-vis absorption (UV-vis) spectroscopy. The possible capping mechanism of the nanoparticles was postulated using FTIR studies. As synthesized biogenic nanoparticles showed excellent catalytic activity as evidenced from sodium borohydride mediated reduction of 4-nitro phenol and methylene blue.

  4. Citrate-Coated Silver Nanoparticles Interactions with Effluent Organic Matter: Influence of Capping Agent and Solution Conditions.

    PubMed

    Gutierrez, Leonardo; Aubry, Cyril; Cornejo, Mauricio; Croue, Jean-Philippe

    2015-08-18

    Fate and transport studies of silver nanoparticles (AgNPs) discharged from urban wastewaters containing effluent organic matter (EfOM) into natural waters represent a key knowledge gap. In this study, EfOM interfacial interactions with AgNPs, and their aggregation kinetics were investigated by atomic force microscopy (AFM) and time-resolved dynamic light scattering (TR-DLS), respectively. Two well-characterized EfOM isolates, i.e., wastewater humic (WW humic) and wastewater colloids (WW colloids, a complex mixture of polysaccharides-proteins-lipids), and a River humic isolate of different characteristics were selected. Citrate-coated AgNPs were selected as representative capped-AgNPs. Citrate-coated AgNPs showed a considerable stability in Na(+) solutions. However, Ca(2+) ions induced aggregation by cation bridging between carboxyl groups on citrate. Although the presence of River humic increased the stability of citrate-coated AgNPs in Na(+) solutions due to electrosteric effects, they aggregated in WW humic-containing solutions, indicating the importance of humics characteristics during interactions. Ca(2+) ions increased citrate-coated AgNPs aggregation rates in both humic solutions, suggesting cation bridging between carboxyl groups on their structures as a dominant interacting mechanism. Aggregation of citrate-coated AgNPs in WW colloids solutions was significantly faster than those in both humic solutions. Control experiments in urea solution indicated hydrogen bonding as the main interacting mechanism. During AFM experiments, citrate-coated AgNPs showed higher adhesion to WW humic than to River humic, evidencing a consistency between TR-DLS and AFM results. Ca(2+) ions increased citrate-coated AgNPs adhesion to both humic isolates. Interestingly, strong WW colloids interactions with citrate caused AFM probe contamination (nanoparticles adsorption) even at low Na(+) concentrations, indicating the impact of hydrogen bonding on adhesion. These results suggest

  5. Chitosan-capped silver nanoparticles as a highly selective colorimetric probe for visual detection of aromatic ortho-trihydroxy phenols.

    PubMed

    Chen, Zhaohui; Zhang, Xiaodan; Cao, Haiyan; Huang, Yuming

    2013-04-21

    We reported a new application of silver nanoparticles (NPs) for the visual sensing of aromatic polyphenols, such as gallic acid, pyrogallol and tannic acid, which is based on the intensified plasmon absorbance signals and visual changes from yellow to orange due to hydrogen-bonding recognition and subsequent catalytic oxidation of the target phenols by chitosan-capped Ag NPs (Ch-Ag NPs). The Ch-Ag NPs are generated by the well-known reaction of AgNO3 with NaBH4 and stabilized with chitosan which is a polysaccharide biopolymer with excellent dispersive properties and stability in aqueous media. After optimizing some experimental conditions, a very simple and facile sensing system has been developed for the detection of gallic acid, pyrogallol and tannic acid in water samples. The proposed system promises high selectivity toward gallic acid, pyrogallol and tannic acid, and other phenolic compounds including p-aminobenzoic acid, pentachlorophenol, 2,4,6-trinitrophenol, 2,4-dinitrophenol, p-nitrophenol, 1-naphthol, β-naphthol, p-aminophenol, catechol, hydroquinone, m-dihydroxybenzene, phloroglucin and phenol could not induce a color change even at 0.1 mM. The outstanding selectivity property of the proposed method for gallic acid, pyrogallol and tannic acid resulted from the Ch-Ag NPs-mediated reduction of Ag(+) by the target phenols. Also, a wide linear response range was obtained for the three targets. The linear response ranges for gallic acid, pyrogallol, and tannic acid were from 1 × 10(-5) to 1 × 10(-3) M, 1 × 10(-5) to 1 × 10(-2) M and 1 × 10(-6) to 1 × 10(-4) M with a respective detection limit (DL) of 1 × 10(-5), 1 × 10(-5), and 1 × 10(-6) M. The proposed method was successfully applied to detect target phenols in environmental water samples. Furthermore, because the color change from yellow to orange is observable by the naked eye, it is easy to realize visual detection of the target phenols without any instrumentation or complicated design. The

  6. Selective turn-on fluorescence sensor for Ag+ using cysteamine capped CdS quantum dots: determination of free Ag+ in silver nanoparticles solution.

    PubMed

    Khantaw, Thitima; Boonmee, Chanida; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2013-10-15

    Cadmium sulfide quantum dots capped with cysteamine (Cys-CdS QDs) were demonstrated as a selective fluorescence probe for sensing of free trace silver ions. The fluorescence intensity of the Cys-CdS QDs can be enhanced only in the presence of free Ag(+) and the fluorescence spectrum was slightly red shift from the original spectra. In addition, the fluorescence intensities were linearly increased upon increasing Ag(+) concentration. At the optimized condition for Ag(+) detection, when adding other metal ions to the Cys-CdS QDs solution, fluorescence spectra of Cys-CdS QDs did not change significantly revealing good selectivity of the sensors towards Ag(+). The working linear concentration range was found to be 0.1-1.5 µM with LOD of 68 nM. The proposed sensor was then applied to detect free Ag(+) in the silver nanoparticles solution. The results showed that the proposed sensor can be efficiently used with good accuracy and precision providing the simple method for detection of free Ag(+) in silver nanoparticles of quality control products.

  7. Polysaccharide-capped silver Nanoparticles inhibit biofilm formation and eliminate multi-drug-resistant bacteria by disrupting bacterial cytoskeleton with reduced cytotoxicity towards mammalian cells

    PubMed Central

    Sanyasi, Sridhar; Majhi, Rakesh Kumar; Kumar, Satish; Mishra, Mitali; Ghosh, Arnab; Suar, Mrutyunjay; Satyam, Parlapalli Venkata; Mohapatra, Harapriya; Goswami, Chandan; Goswami, Luna

    2016-01-01

    Development of effective anti-microbial therapeutics has been hindered by the emergence of bacterial strains with multi-drug resistance and biofilm formation capabilities. In this article, we report an efficient green synthesis of silver nanoparticle (AgNP) by in situ reduction and capping with a semi-synthetic polysaccharide-based biopolymer (carboxymethyl tamarind polysaccharide). The CMT-capped AgNPs were characterized by UV, DLS, FE-SEM, EDX and HR-TEM. These AgNPs have average particle size of ~20–40 nm, and show long time stability, indicated by their unchanged SPR and Zeta-potential values. These AgNPs inhibit growth and biofilm formation of both Gram positive (B. subtilis) and Gram negative (E. coli and Salmonella typhimurium) bacterial strains even at concentrations much lower than the minimum inhibitory concentration (MIC) breakpoints of antibiotics, but show reduced or no cytotoxicity against mammalian cells. These AgNPs alter expression and positioning of bacterial cytoskeletal proteins FtsZ and FtsA. CMT-capped AgNPs can effectively block growth of several clinical isolates and MDR strains representing different genera and resistant towards multiple antibiotics belonging to different classes. We propose that the CMT-capped AgNPs can have potential bio-medical application against multi-drug-resistant microbes with minimal cytotoxicity towards mammalian cells. PMID:27125749

  8. Polysaccharide-capped silver Nanoparticles inhibit biofilm formation and eliminate multi-drug-resistant bacteria by disrupting bacterial cytoskeleton with reduced cytotoxicity towards mammalian cells

    NASA Astrophysics Data System (ADS)

    Sanyasi, Sridhar; Majhi, Rakesh Kumar; Kumar, Satish; Mishra, Mitali; Ghosh, Arnab; Suar, Mrutyunjay; Satyam, Parlapalli Venkata; Mohapatra, Harapriya; Goswami, Chandan; Goswami, Luna

    2016-04-01

    Development of effective anti-microbial therapeutics has been hindered by the emergence of bacterial strains with multi-drug resistance and biofilm formation capabilities. In this article, we report an efficient green synthesis of silver nanoparticle (AgNP) by in situ reduction and capping with a semi-synthetic polysaccharide-based biopolymer (carboxymethyl tamarind polysaccharide). The CMT-capped AgNPs were characterized by UV, DLS, FE-SEM, EDX and HR-TEM. These AgNPs have average particle size of ~20–40 nm, and show long time stability, indicated by their unchanged SPR and Zeta-potential values. These AgNPs inhibit growth and biofilm formation of both Gram positive (B. subtilis) and Gram negative (E. coli and Salmonella typhimurium) bacterial strains even at concentrations much lower than the minimum inhibitory concentration (MIC) breakpoints of antibiotics, but show reduced or no cytotoxicity against mammalian cells. These AgNPs alter expression and positioning of bacterial cytoskeletal proteins FtsZ and FtsA. CMT-capped AgNPs can effectively block growth of several clinical isolates and MDR strains representing different genera and resistant towards multiple antibiotics belonging to different classes. We propose that the CMT-capped AgNPs can have potential bio-medical application against multi-drug-resistant microbes with minimal cytotoxicity towards mammalian cells.

  9. 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

  10. Green synthesis and antibacterial effects of aqueous colloidal solutions of silver nanoparticles using camomile terpenoids as a combined reducing and capping agent.

    PubMed

    Parlinska-Wojtan, Magdalena; Kus-Liskiewicz, Małgorzata; Depciuch, Joanna; Sadik, Omowunmi

    2016-08-01

    Green synthesis method using camomile extract was applied to synthesize silver nanoparticles to tune their antibacterial properties merging the synergistic effect of camomile and Ag. Scanning transmission electron microscopy revealed that camomile extract (CE) consisted of porous globular nanometer sized structures, which were a perfect support for Ag nanoparticles. The Ag nanoparticles synthesized with the camomile extract (AgNPs/CE) of 7 nm average sizes, were uniformly distributed on the CE support, contrary to the pure Ag nanoparticles synthesized with glucose (AgNPs/G), which were over 50 nm in diameter and strongly agglomerated. The energy dispersive X-ray spectroscopy chemical analysis showed that camomile terpenoids act as a capping and reducing agent being adsorbed on the surface of AgNPs/CE enabling their reduction from Ag(+) and preventing them from agglomeration. Fourier transform infrared and ultraviolet-visible spectroscopy measurements confirmed these findings, as the spectra of AgNPs/CE, compared to pure CE, did not contain the 1109 cm(-1) band, corresponding to -C-O groups of terpenoids and the peaks at 280 and 320 nm, respectively. Antibacterial tests using four bacteria strains showed that the AgNPs/CE performed five times better compared to CE AgNPs/G samples, reducing totally all the bacteria in 2 h.

  11. Antimicrobial and cell viability measurement of bovine serum albumin capped silver nanoparticles (Ag/BSA) loaded collagen immobilized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) film.

    PubMed

    Bakare, Rotimi; Hawthrone, Samantha; Vails, Carmen; Gugssa, Ayele; Karim, Alamgir; Stubbs, John; Raghavan, Dharmaraj

    2016-03-01

    Bacterial infection of orthopedic devices has been a major concern in joint replacement procedures. Therefore, this study is aimed at formulating collagen immobilized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) film loaded with bovine serum albumin capped silver nanoparticles (Ag/BSA NPs) to inhibit bacterial growth while retaining/promoting osteoblast cells viability. The nanoparticles loaded collagen immobilized PHBV film was characterized for its composition by X-ray Photoelectron Spectroscopy and Anodic Stripping Voltammetry. The extent of loading of Ag/BSA NPs on collagen immobilized PHBV film was found to depend on the chemistry of the functionalized PHBV film and the concentration of Ag/BSA NPs solution used for loading nanoparticles. Our results showed that more Ag/BSA NPs were loaded on higher molecular weight collagen immobilized PHEMA-g-PHBV film. Maximum loading of Ag/BSA NPs on collagen immobilized PHBV film was observed when 16ppm solution was used for adsorption studies. Colony forming unit and optical density measurements showed broad antimicrobial activity towards Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa at significantly lower concentration i.e., 0.19 and 0.31μg/disc, compared to gentamicin and sulfamethoxazole trimethoprim while MTT assay showed that released nanoparticles from Ag/BSA NPs loaded collagen immobilized PHBV film has no impact on MCTC3-E1 cells viability.

  12. Capping Agent-Dependent Toxicity and Antimicrobial Activity of Silver Nanoparticles: An In Vitro Study. Concerns about Potential Application in Dental Practice

    PubMed Central

    Niska, Karolina; Knap, Narcyz; Kędzia, Anna; Jaskiewicz, Maciej; Kamysz, Wojciech; Inkielewicz-Stepniak, Iwona

    2016-01-01

    Objectives: In dentistry, silver nanoparticles (AgNPs) have drawn particular attention because of their wide antimicrobial activity spectrum. However, controversial information on AgNPs toxicity limited their use in oral infections. Therefore, the aim of the present study was to evaluate the antibacterial activities against a panel of oral pathogenic bacteria and bacterial biofilms together with potential cytotoxic effects on human gingival fibroblasts of 10 nm AgNPs: non-functionalized - uncapped (AgNPs-UC) as well as surface-functionalized with capping agent: lipoic acid (AgNPs-LA), polyethylene glycol (AgNPs-PEG) or tannic acid (AgNPs-TA) using silver nitrate (AgNO3) as control. Methods: The interaction of AgNPs with human gingival fibroblast cells (HGF-1) was evaluated using the mitochondrial metabolic potential assay (MTT). Antimicrobial activity of AgNPs was tested against anaerobic Gram-positive and Gram-negative bacteria isolated from patients with oral cavity and respiratory tract infections, and selected aerobic Staphylococci strains. Minimal inhibitory concentration (MIC) values were determined by the agar dilution method for anaerobic bacteria or broth microdilution method for reference Staphylococci strains and Streptococcus mutans. These strains were also used for antibiofilm activity of AgNPs. Results: The highest antimicrobial activities at nontoxic concentrations were observed for the uncapped AgNPs and the AgNPs capped with LA. It was found that AgNPs-LA and AgNPs-PEG demonstrated lower cytotoxicity as compared with the AgNPs-TA or AgNPs-UC in the gingival fibroblast model. All of the tested nanoparticles proved less toxic and demonstrated wider spectrum of antimicrobial activities than AgNO3 solution. Additionally, AgNPs-LA eradicated Staphylococcus epidermidis and Streptococcus mutans 1-day biofilm at concentration nontoxic to oral cells. Conclusions: Our results proved that a capping agent had significant influence on the antibacterial

  13. Capping Agent-Dependent Toxicity and Antimicrobial Activity of Silver Nanoparticles: An In Vitro Study. Concerns about Potential Application in Dental Practice.

    PubMed

    Niska, Karolina; Knap, Narcyz; Kędzia, Anna; Jaskiewicz, Maciej; Kamysz, Wojciech; Inkielewicz-Stepniak, Iwona

    2016-01-01

    Objectives: In dentistry, silver nanoparticles (AgNPs) have drawn particular attention because of their wide antimicrobial activity spectrum. However, controversial information on AgNPs toxicity limited their use in oral infections. Therefore, the aim of the present study was to evaluate the antibacterial activities against a panel of oral pathogenic bacteria and bacterial biofilms together with potential cytotoxic effects on human gingival fibroblasts of 10 nm AgNPs: non-functionalized - uncapped (AgNPs-UC) as well as surface-functionalized with capping agent: lipoic acid (AgNPs-LA), polyethylene glycol (AgNPs-PEG) or tannic acid (AgNPs-TA) using silver nitrate (AgNO3) as control. Methods: The interaction of AgNPs with human gingival fibroblast cells (HGF-1) was evaluated using the mitochondrial metabolic potential assay (MTT). Antimicrobial activity of AgNPs was tested against anaerobic Gram-positive and Gram-negative bacteria isolated from patients with oral cavity and respiratory tract infections, and selected aerobic Staphylococci strains. Minimal inhibitory concentration (MIC) values were determined by the agar dilution method for anaerobic bacteria or broth microdilution method for reference Staphylococci strains and Streptococcus mutans. These strains were also used for antibiofilm activity of AgNPs. Results: The highest antimicrobial activities at nontoxic concentrations were observed for the uncapped AgNPs and the AgNPs capped with LA. It was found that AgNPs-LA and AgNPs-PEG demonstrated lower cytotoxicity as compared with the AgNPs-TA or AgNPs-UC in the gingival fibroblast model. All of the tested nanoparticles proved less toxic and demonstrated wider spectrum of antimicrobial activities than AgNO3 solution. Additionally, AgNPs-LA eradicated Staphylococcus epidermidis and Streptococcus mutans 1-day biofilm at concentration nontoxic to oral cells. Conclusions: Our results proved that a capping agent had significant influence on the antibacterial

  14. Anaerobic Toxicity of Cationic Silver Nanoparticles

    EPA Science Inventory

    The microbial toxicity of silver nanoparticles (AgNPs) stabilized with different capping agents was compared to that of Ag+ under anaerobic conditions. Three AgNPs were investigated: (1) negatively charged citrate-coated AgNPs (citrate-AgNPs), (2) minimally charged p...

  15. Antimicrobial activity of biogenic silver nanoparticles, and silver chloride nanoparticles: an overview and comments.

    PubMed

    Durán, Nelson; Nakazato, Gerson; Seabra, Amedea B

    2016-08-01

    The antimicrobial impact of biogenic-synthesized silver-based nanoparticles has been the focus of increasing interest. As the antimicrobial activity of nanoparticles is highly dependent on their size and surface, the complete and adequate characterization of the nanoparticle is important. This review discusses the characterization and antimicrobial activity of biogenic synthesized silver nanoparticles and silver chloride nanoparticles. By revising the literature, there is confusion in the characterization of these two silver-based nanoparticles, which consequently affects the conclusion regarding to their antimicrobial activities. This review critically analyzes recent publications on the synthesis of biogenic silver nanoparticles and silver chloride nanoparticles by attempting to correlate the characterization of the nanoparticles with their antimicrobial activity. It was difficult to correlate the size of biogenic nanoparticles with their antimicrobial activity, since different techniques are employed for the characterization. Biogenic synthesized silver-based nanoparticles are not completely characterized, particularly the nature of capped proteins covering the nanomaterials. Moreover, the antimicrobial activity of theses nanoparticles is assayed by using different protocols and strains, which difficult the comparison among the published papers. It is important to select some bacteria as standards, by following international foundations (Pharmaceutical Microbiology Manual) and use the minimal inhibitory concentration by broth microdilution assays from Clinical and Laboratory Standards Institute, which is the most common assay used in antibiotic ones. Therefore, we conclude that to have relevant results on antimicrobial effects of biogenic silver-based nanoparticles, it is necessary to have a complete and adequate characterization of these nanostructures, followed by standard methodology in microbiology protocols.

  16. Silver nanoparticles with tunable work functions

    SciTech Connect

    Wang, Pangpang; Tanaka, Daisuke; Ryuzaki, Sou; Araki, Shohei; Okamoto, Koichi; Tamada, Kaoru

    2015-10-12

    To improve the efficiencies of electronic devices, materials with variable work functions are required to decrease the energy level differences at the interfaces between working layers. Here, we report a method to obtain silver nanoparticles with tunable work functions, which have the same silver core of 5 nm in diameter and are capped by myristates and 1-octanethoilates self-assembled monolayers, respectively. The silver nanoparticles capped by organic molecules can form a uniform two-dimensional sheet at air-water interface, and the sheet can be transferred on various hydrophobic substrates. The surface potential of the two-dimensional nanoparticle sheet was measured in terms of Kelvin probe force microscopy, and the work function of the sheet was then calculated from the surface potential value by comparing with a reference material. The exchange of the capping molecules results in a work function change of approximately 150–250 meV without affecting their hydrophobicity. We systematically discussed the origin of the work function difference and found it should come mainly from the anchor groups of the ligand molecules. The organic molecule capped nanoparticles with tunable work functions have a potential for the applications in organic electronic devices.

  17. 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

  18. Synthesis of 1-dodecanethiol-capped Ag nanoparticles and their high catalytic activity

    NASA Astrophysics Data System (ADS)

    Zhang, Danhui; Yang, Youbo

    2017-01-01

    Silver nanoparticles, which were produced by the borohydride reduction of silver nitrate, were stabilized by means of 1-dodecanethiol providing sulfur atom in two-phase system involving water and organic solvent (such as toluene, chloroform and hexane). Different organic solvent played a major role in the particle size of silver nanoparticles. These silver nanoparticles synthesized in the three different organic solvent were characterized by X-ray Diffraction, transmission electron microscopy and ultraviolet-visible absorption spectroscopy. The results indicate that the particles size of silver nanoparticles formed in three organic solvents was different. Furthermore, 1-dodecanethiol-capped silver nanoparticles were found to serve as effective catalysts to activate the reduction of 4-nitrophenol (4NP) in the presence of NaBH4, where the size of silver nanoparticles played the determining role in catalytic activity.

  19. Synthesis of silver nanoparticles using medicinal Zizyphus xylopyrus bark extract

    NASA Astrophysics Data System (ADS)

    Sumi Maria, Babu; Devadiga, Aishwarya; Shetty Kodialbail, Vidya; Saidutta, M. B.

    2015-08-01

    In the present paper, biosynthesis of silver nanoparticles using Zizyphus xylopyrus bark extract is reported. Z. xylopyrus bark extract is efficiently used for the biosynthesis of silver nanoparticles. UV-Visible spectroscopy showed surface plasmon resonance peaks in the range 413-420 nm confirming the formation of silver nanoparticles. Different factors affecting the synthesis of silver nanoparticles like methodology for the preparation of extract, concentration of silver nitrate solution used for biosynthesis and initial pH of the reaction mixture were studied. The extract prepared with 10 mM AgNO3 solution by reflux extraction method at optimum initial pH of 11, resulted in higher conversion of silver ions to silver nanoparticles as compared with those prepared by open heating or ultrasonication. SEM analysis showed that the biosynthesized nanoparticles are spherical in nature and ranged from 60 to 70 nm in size. EDX suggested that the silver nanoparticles must be capped by the organic components present in the plant extract. This simple process for the biosynthesis of silver nanoparticles using aqueous extract of Z. xylopyrus is a green technology without the usage of hazardous and toxic solvents and chemicals and hence is environment friendly. The process has several advantages with reference to cost, compatibility for its application in medical and drug delivery, as well as for large-scale commercial production.

  20. Multifunctional PLGA particles containing poly(l-glutamic acid)-capped silver nanoparticles and ascorbic acid with simultaneous antioxidative and prolonged antimicrobial activity.

    PubMed

    Stevanović, Magdalena; Bračko, Ines; Milenković, Marina; Filipović, Nenad; Nunić, Jana; Filipič, Metka; Uskoković, Dragan P

    2014-01-01

    A water-soluble antioxidant (ascorbic acid, vitamin C) was encapsulated together with poly(l-glutamic acid)-capped silver nanoparticles (AgNpPGA) within a poly(lactide-co-glycolide) (PLGA) polymeric matrix and their synergistic effects were studied. The PLGA/AgNpPGA/ascorbic acid particles synthesized by a physicochemical method with solvent/non-solvent systems are spherical, have a mean diameter of 775 nm and a narrow size distribution with a polydispersity index of 0.158. The encapsulation efficiency of AgNpPGA/ascorbic acid within PLGA was determined to be >90%. The entire amount of encapsulated ascorbic acid was released in 68 days, and the entire amount of AgNpPGAs was released in 87 days of degradation. The influence of PLGA/AgNpPGA/ascorbic acid on cell viability, generation of reactive oxygen species (ROS) in HepG2 cells, as well as antimicrobial activity against seven different pathogens was investigated. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated good biocompatibility of these PLGA/AgNpPGA/ascorbic acid particles. We measured the kinetics of ROS formation in HepG2 cells by a DCFH-DA assay, and found that PLGA/AgNpPGA/ascorbic acid caused a significant decrease in DCF fluorescence intensity, which was 2-fold lower than that in control cells after a 5h exposure. This indicates that the PLGA/AgNpPGA/ascorbic acid microspheres either act as scavengers of intracellular ROS and/or reduce their formation. Also, the results of antimicrobial activity of PLGA/AgNpPGA/ascorbic acid obtained by the broth microdilution method showed superior and extended activity of these particles. The samples were characterized using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, zeta potential and particle size analysis. This paper presents a new approach to the treatment of infection that at the same time offers a very pronounced antioxidant effect.

  1. From silver nanoparticles to nanostructures through matrix chemistry

    NASA Astrophysics Data System (ADS)

    Ayyad, Omar; Muñoz-Rojas, David; Oró-Solé, Judith; Gómez-Romero, Pedro

    2010-01-01

    Direct in situ reduction of silver ions by a biopolymer such as agar, without any other reducing nor capping agent is shown in this article to lead either to nanoparticles (typically 12(2) nm in an optimized case) or to more complex nanostructures depending on the reaction conditions used. This approach takes advantage of the porous polymer lattice acting as a template and leads to hybrid Ag-Agar materials with long-term synergic stability. Silver acts as an antibacterial agent for agar whereas the biopolymer prevents agglomeration of the inorganic nanoparticles leading to a stable nanocomposite formed by a thermoreversible biopolymer from which silver nanoparticles can eventually be recovered.

  2. Synthesis, characterization and SERS activity of biosynthesized silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Bindhu, M. R.; Sathe, V.; Umadevi, M.

    2013-11-01

    Silver nanoparticles were rapidly synthesized using Moringa oleifera flower extract as the reducing agent shows surface plasmon resonance peak at 439 nm. The size and shape of the nanoparticles controlled by varying the concentration of M. oleifera flower extract in the reaction medium. The synthesized silver nanoparticles were well-dispersed spherical nanoparticles with the average size of 14 nm. The retinoic acid present in M. oleifera flower extract used as reducing agent and proteins was responsible for capping of the bioreduced silver nanoparticles. The obtained nanoparticle shows size-dependent SERS activity. The SERS spectrum indicates that the pyridine adsorbed on the silver surface in a stand-on orientation via its nitrogen lone pair electrons.

  3. Toxicity of silver nanoparticles against bacteria, yeast, and algae

    NASA Astrophysics Data System (ADS)

    Dorobantu, Loredana S.; Fallone, Clara; Noble, Adam J.; Veinot, Jonathan; Ma, Guibin; Goss, Greg G.; Burrell, Robert E.

    2015-04-01

    The toxicity mechanism employed by silver nanoparticles against microorganisms has captivated scientists for nearly a decade and remains a debatable issue. The question most frequently asked is whether silver nanoparticles exert specific effects on microorganisms beyond the well-documented antimicrobial activity of Ag+. Here, we study the effects of citrate- (d = 17.5 ± 9.4 nm) and 11-mercaptoundecanoic acid (d = 38.8 ± 3.6 nm)-capped silver nanoparticles on microorganisms belonging to various genera. The antimicrobial effect of Ag+ was distinguished from that of nanosilver by monitoring microbial growth in the presence and absence of nanoparticles and by careful comparison of the responses of equimolar silver nitrate solution. The results show that when using equimolar silver solutions, silver nitrate has higher toxic potential on all microorganisms than both nanoparticles tested. Furthermore, some microorganisms are more susceptible to silver than others and the choice of capping agent is relevant in the toxicity. Atomic force microscopy disclosed that AgNO3 had a destructive effect on algae. The antimicrobial activity of nanosilver could be exploited to prevent microbial colonization of medical devices and to determine the fate of nanoparticles in the environment.

  4. Toxicity of silver nanoparticles in zebrafish models.

    PubMed

    Asharani, P V; Lian Wu, Yi; Gong, Zhiyuan; Valiyaveettil, Suresh

    2008-06-25

    This study was initiated to enhance our insight on the health and environmental impact of silver nanoparticles (Ag-np). Using starch and bovine serum albumin (BSA) as capping agents, silver nanoparticles were synthesized to study their deleterious effects and distribution pattern in zebrafish embryos (Danio rerio). Toxicological endpoints like mortality, hatching, pericardial edema and heart rate were recorded. A concentration-dependent increase in mortality and hatching delay was observed in Ag-np treated embryos. Additionally, nanoparticle treatments resulted in concentration-dependent toxicity, typified by phenotypes that had abnormal body axes, twisted notochord, slow blood flow, pericardial edema and cardiac arrhythmia. Ag(+) ions and stabilizing agents showed no significant defects in developing embryos. Transmission electron microscopy (TEM) of the embryos demonstrated that nanoparticles were distributed in the brain, heart, yolk and blood of embryos as evident from the electron-dispersive x-ray analysis (EDS). Furthermore, the acridine orange staining showed an increased apoptosis in Ag-np treated embryos. These results suggest that silver nanoparticles induce a dose-dependent toxicity in embryos, which hinders normal development.

  5. Synthesis and characterization of collagen grafted poly(hydroxybutyrate-valerate) (PHBV) scaffold for loading of bovine serum albumin capped silver (Ag/BSA) nanoparticles in the potential use of tissue engineering application.

    PubMed

    Bakare, Rotimi A; Bhan, Chandra; Raghavan, Dharmaraj

    2014-01-13

    The objective of this study is to synthesize and characterize collagen grafted poly(3-hydroxylbutyrate-co-3-hydroxylvalerate) (PHBV) film for loading of BSA capped silver (Ag/BSA) nanoparticles. Thermal radical copolymerization and aminolysis methods were used to functionalize macroporous PHBV, followed by collagen grafting so as to formulate collagen-g-poly(hydroxyethylmethyl acrylate)-g-poly(3-hydroxylbutyrate-co-3-hydroxylvalerate) [collagen-g-PHEMA-g-PHBV] and collagen-g-aminated-poly(3-hydroxylbutyrate-co-3-hydroxylvalerate) [collagen-g-NH2-PHBV] films, respectively. Spectroscopic (FTIR, XPS), physical (SEM), and thermal (TGA) techniques were used to characterize the functionalized PHBV films. The amount of collagen present on grafted PHBV film was quantified by the Bradford method. The Ag/BSA nanoparticles were then loaded on collagen grafted and untreated PHBV films, and the nanoparticles loading were determined by atomic absorption spectrometry. The amount of nanoparticles loaded on collagen grafted PHBV film was found to be significantly greater than that on the untreated PHBV film. The nanoparticles loaded PHBV film can potentially serve as a scaffold to promote the growth of bone cells while inhibiting the bacterial growth.

  6. Malva parviflora extract assisted green synthesis of silver nanoparticles.

    PubMed

    Zayed, Mervat F; Eisa, Wael H; Shabaka, A A

    2012-12-01

    Five plant leaf extracts (Malva parviflora, Beta vulgaris subsp. Vulgaris, Anethum graveolens, Allium kurrat and Capsicum frutescens) were screened for their bioreduction behavior for synthesis of silver nanoparticles. M. parviflora (Malvaceae) was found to exhibit the best reducing and protecting action in terms of synthesis rate and monodispersity of the prepared silver nanoparticles. Our measurements indicate that biosynthesis of Ag nanoparticles by M. parviflora produces Ag nanoparticles with the diameters in the range of 19-25 nm. XRD studies reveal a high degree of crystallinity and monophasic Ag nanoparticles of face-centered cubic structure. FTIR analysis proved that particles are reduced and stabilized in solution by the capping agent that is likely to be proteins secreted by the biomass. The present process is an excellent candidate for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive.

  7. Malva parviflora extract assisted green synthesis of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Zayed, Mervat F.; Eisa, Wael H.; Shabaka, A. A.

    2012-12-01

    Five plant leaf extracts (Malva parviflora, Beta vulgaris subsp. Vulgaris, Anethum graveolens, Allium kurrat and Capsicum frutescens) were screened for their bioreduction behavior for synthesis of silver nanoparticles. M. parviflora (Malvaceae) was found to exhibit the best reducing and protecting action in terms of synthesis rate and monodispersity of the prepared silver nanoparticles. Our measurements indicate that biosynthesis of Ag nanoparticles by M. parviflora produces Ag nanoparticles with the diameters in the range of 19-25 nm. XRD studies reveal a high degree of crystallinity and monophasic Ag nanoparticles of face-centered cubic structure. FTIR analysis proved that particles are reduced and stabilized in solution by the capping agent that is likely to be proteins secreted by the biomass. The present process is an excellent candidate for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive.

  8. 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...

  9. Anaerobic Toxicity of Cationic Silver Nanoparticles | Science ...

    EPA Pesticide Factsheets

    The microbial toxicity of silver nanoparticles (AgNPs) stabilized with different capping agents was compared to that of Ag+ under anaerobic conditions. Three AgNPs were investigated: (1) negatively charged citrate-coated AgNPs (citrate-AgNPs), (2) minimally charged polyvinylpyrrolidone coated AgNPs (PVP-AgNps) and (3) positively charged branched polyethyleneimine coated AgNPs (BPEI-AgNPs). The AgNPs investigated in this experiment were similar in size (10-15 nm), spherical in shape, but varied in surface charge which ranged from highly negative to highly positive. While, at AgNPs concentrations lower than 5 mg L-1, the anaerobic decomposition process was not influenced by the presence of the nanoparticles, there was an observed impact on the diversity of the microbial community. At elevated concentrations (100 mg L-1 as silver), only the cationic BPEI-AgNPs demonstrated toxicity similar in magnitude to that of Ag+. Both citrate and PVP-AgNPs did not exhibit toxicity at the 100 mg L-1 as measured by biogas evolution. These findings further indicate the varying modes of action for nanoparticle toxicity and represent one of the few studies that evaluate end-of-life management concerns with regards to the increasing use of nanomaterials in our everyday life. These findings also highlight some of the concerns with a one size fits all approach to the evaluation of environmental health and safety concerns associated with the use of nanoparticles. The current

  10. Fusarium solani: a novel biological agent for the extracellular synthesis of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Ingle, Avinash; Rai, Mahendra; Gade, Aniket; Bawaskar, Manisha

    2009-11-01

    We report extracellular biosynthesis of silver nanoparticles by Fusarium solani (USM-3799), a phytopathogen causing disease in onion, when challenged with 1 mM silver nitrate (AgNO3). The formation of nanoparticles was characterized by visual observation followed by UV-Vis spectrophotometric analysis, which showed a peak at about 420 nm, which is very specific for silver nanoparticles. Further analysis carried out by Fourier Transform Infrared Spectroscopy (FTIR), provides evidence for the presence of proteins as capping agent, which helps in increasing the stability of the synthesized silver nanoparticles. Transmission Electron Microscopy (TEM) investigations confirmed that silver nanoparticles were formed. The synthesized silver nanoparticles were found to be polydispersed, spherical in the range of 5-35 nm with average diameter of 16.23 nm. Extracellular synthesis of nanoparticles could be highly advantageous from the point of view of synthesis in large quantities and easy downstream processing.

  11. 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

  12. Synthesis of biomacromolecule-stabilized silver nanoparticles and their surface-enhanced Raman scattering properties

    NASA Astrophysics Data System (ADS)

    Zhang, Danhui; Yang, Houbo

    2013-09-01

    In this work, water soluble silver nanoparticles stabilized by biomacromolecule, were produced through using an aqueous solution of silver nitrate with Bovine Serum Albumin (BSA) under different reducing agents (such as sodium borohydride, hydrazine, N, N-dimethyl formamide) at the room temperature, where BSA provided the main function to form monodispersed silver nanoparticles. UV-vis spectroscopy, Fluorescence spectra, TEM and HR-TEM are used to characterize the BSA-capped silver nanoparticles under different condition. The results show that the formed silver nanoparticles have different size and morphology under the three different reducing agents. Moreover, the fluorescence intensity of BSA was drastically quenched in presence of Ag nanoparticles from the results of fluorescence spectra. Furthermore, the surface-enhanced Raman scattering effects of the formed silver nanoparticles were also displayed and we made a comparison under three different reducing agents.

  13. 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.

  14. Iodine-125 radiolabeling of silver nanoparticles for in vivo SPECT imaging

    PubMed Central

    Chrastina, Adrian; Schnitzer, Jan E

    2010-01-01

    Silver nanoparticles are increasingly finding applications in medicine; however, little is known about their in vivo tissue distribution. Here, we have developed a rapid method for radiolabeling of silver nanoparticles with iodine-125 in order to track in vivo tissue uptake of silver nanoparticles after systemic administration by biodistribution analysis and single-photon emission computerized tomography (SPECT) imaging. Poly(N-vinyl-2 -pyrrolidone)-capped silver nanoparticles with an average size of 12 nm were labeled by chemisorption of iodine-125 with a > 80% yield of radiolabeling efficiency. Radiolabeled silver nanoparticles were intravenously injected in Balb/c mice, and the in vivo distribution pattern of these nanoparticles was evaluated by noninvasive whole-body SPECT imaging, which revealed uptake of the nanoparticles in the liver and spleen. Biodistribution analysis confirmed predominant accumulation of the silver nanoparticles in the spleen (41.5%ID/g) and liver (24.5%ID/g) at 24 h. Extensive uptake in the tissues of the reticuloendothelial system suggests that further investigation of silver nanoparticle interaction with hepatic and splenic tissues at the cellular level is critical for evaluation of the in vivo effects and potential toxicity of silver nanoparticles. This method enables rapid iodine-125 radiolabeling of silver nanoparticles with a specific activity sufficient for in vivo imaging and biodistribution analysis. PMID:20856841

  15. Coconut water assisted green synthesis of silver nanoparticles

    PubMed Central

    Elumalai, Erusan Kuppan; Kayalvizhi, Karuppsamy; Silvan, Simon

    2014-01-01

    Aim of the Study: The synthesis, characterization and application of biologically synthesized nanomaterials are an important aspect in nanotechnology. Materials and Methods: The present study deals with the synthesis of silver nanoparticles (Ag-NPs) using the coconut water (C. nucifera) as the reducing agent. The formation of Ag-NPs was characterized by UV-Visible Spectroscopy, Scanning Electron Microscopy (SEM), EDX, X-ray Diffraction (XRD) and FTIR spectroscopy. Results: The synthesized Ag-NPs were predominately polydispersed. Crystalline nature of the nanoparticle in the face centered cubic (fcc) structure are confirmed by the peaks in the XRD pattern corresponding to (111), (200), (220) and (311) planes. Fourier Transform Infra-Red (FT-IR) spectroscopy analysis showed that the synthesized nanoparicles was capped with bimolecular compounds which are responsible for the reduction of silver ions. Conclusion: The approach of green synthesis appears to be cost efficient, ecofriendly and easy alternative to conventional methods of silver nanoparticle synthesis. PMID:25400406

  16. Preparation of New Reducing Agent for the Synthesis of Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Manivel, P.; Sivashanmugan, K.; Viswanathan, C.; Mangalaraj, D.

    2011-07-01

    2,3,5,6-Tetrakis-(morpholinomethyl)hydroquinone (TMMH) is used first time to prepare spherical silver nanoparticles by the reduction of Silver nitrate (AgNO3) in water-ethanol medium without using any stabilizing and capping agent. The compound (TMMH) was isolated by aminomethylation of hydroquinone with morpholine. The resultant compound characterized by 1H NMR, 13C NMR and FT-IR Spectra for conformation studies. The ratio of AgNO3 and compound (TMMH) played role in controlling the particle size and shape of silver nanoparticles. The formation of the silver nanoparticles was observed in UV-Vis absorption spectroscopy.

  17. 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.

  18. Synthesis of surface bound silver nanoparticles on cellulose fibers using lignin as multi-functional agent.

    PubMed

    Hu, Sixiao; Hsieh, You-Lo

    2015-10-20

    Lignin has proven to be highly effective "green" multi-functional binding, complexing and reducing agents for silver cations as well as capping agents for the synthesis of silver nanoparticles on ultra-fine cellulose fibrous membranes. Silver nanoparticles could be synthesized in 10min to be densely distributed and stably bound on the cellulose fiber surfaces at up to 2.9% in mass. Silver nanoparticle increased in sizes from 5 to 100nm and became more polydispersed in size distribution on larger fibers and with longer synthesis time. These cellulose fiber bound silver nanoparticles did not agglomerate under elevated temperatures and showed improved thermal stability. The presence of alkali lignin conferred moderate UV absorbing ability in both UV-B and UV-C regions whereas the bound silver nanoparticles exhibited excellent antibacterial activities toward Escherichia coli.

  19. Highly bacterial resistant silver nanoparticles: synthesis and antibacterial activities

    NASA Astrophysics Data System (ADS)

    Chudasama, Bhupendra; Vala, Anjana K.; Andhariya, Nidhi; Mehta, R. V.; Upadhyay, R. V.

    2010-06-01

    In this article, we describe a simple one-pot rapid synthesis route to produce uniform silver nanoparticles by thermal reduction of AgNO3 using oleylamine as reducing and capping agent. To enhance the dispersal ability of as-synthesized hydrophobic silver nanoparticles in water, while maintaining their unique properties, a facile phase transfer mechanism has been developed using biocompatible block co-polymer pluronic F-127. Formation of silver nanoparticles is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectroscopy. Hydrodynamic size and its distribution are obtained from dynamic light scattering (DLS). Hydrodynamic size and size distribution of as-synthesized and phase transferred silver nanoparticles are 8.2 ± 1.5 nm (σ = 18.3%) and 31.1 ± 4.5 nm (σ = 14.5%), respectively. Antimicrobial activities of hydrophilic silver nanoparticles is tested against two Gram positive ( Bacillus megaterium and Staphylococcus aureus), and three Gram negative ( Escherichia coli, Proteus vulgaris and Shigella sonnei) bacteria. Minimum inhibitory concentration (MIC) values obtained in the present study for the tested microorganisms are found much better than those reported for commercially available antibacterial agents.

  20. Morphological transformations of silver nanoparticles in seedless photochemical synthesis

    NASA Astrophysics Data System (ADS)

    Lu, Ya; Zhang, Congyun; Hao, Rui; Zhang, Dongjie; Fu, Yizheng; Moeendarbari, Sina; Pickering, Christopher S.; Hao, Yaowu; Liu, Yaqing

    2016-05-01

    Photochemical synthesis is an easily controlled and reliable method for the fabrication of silver (Ag) nanoparticles with various morphologies. In this work, we have systematically investigated the seedless photochemical synthesis of anisotropic Ag nanoparticles with and without PVP as surface capping agent. The time evolution of anisotropic Ag nanoparticles during the synthesis process are studied using UV-visible spectra, optical images and transmission electron microscopy. The results show that the light irradiation precisely controls the start and termination of the reaction, and the presence or absence of PVP greatly affects the morphology evolution of anisotropic Ag nanoparticles. With PVP as the surface capping agent, Ag nanoparticles grow into decahedra or prism by the deposition of Ag atoms on {111} or {110} facets through epitaxial growth. However, a different morphology evolution could happen when Ag nanoparticle is synthesized without PVP as surface capping agent. In this case, Ag nanoparticles can fuse into the decahedrons through an edge-selective particle fusion mechanism, which involves attachment, rotation and realignment of Ag nanoparticles. This process was evidenced with HRTEM images at the different stages of the transformation from Ag colloid to decahedra nanoparticles. Oriented attachment and Ostwald ripening also play important role in the transformation process.

  1. Efficient synthesis of silver nanoparticles from Prosopis juliflora leaf extract and its antimicrobial activity using sewage

    NASA Astrophysics Data System (ADS)

    Raja, K.; Saravanakumar, A.; Vijayakumar, R.

    2012-11-01

    In this paper, aqueous extract of fresh leaves of Prosopis juliflora was used for the synthesis of silver (Ag) nanoparticles. UV-Vis spectroscopy studies were carried out to asses silver nanoparticles formation within 5 min, scanning electron microscopic was used to characterize shape of the Ag nanoparticles, X-ray diffraction analysis confirms the nanoparticles as crystalline silver and facecentered cubic type and Fourier transform infra-red assed that shows biomolecule compounds which are responsible for reduction and capping material of silver nanoparticles. The anti microbial activity of silver nanoparticle was performed using sewage. The approach of plant-mediated synthesis appears to be cost efficient, eco-friendly and easy methods.

  2. Efficient synthesis of silver nanoparticles from Prosopis juliflora leaf extract and its antimicrobial activity using sewage.

    PubMed

    Raja, K; Saravanakumar, A; Vijayakumar, R

    2012-11-01

    In this paper, aqueous extract of fresh leaves of Prosopis juliflora was used for the synthesis of silver (Ag) nanoparticles. UV-Vis spectroscopy studies were carried out to asses silver nanoparticles formation within 5 min, scanning electron microscopic was used to characterize shape of the Ag nanoparticles, X-ray diffraction analysis confirms the nanoparticles as crystalline silver and facecentered cubic type and Fourier transform infra-red assed that shows biomolecule compounds which are responsible for reduction and capping material of silver nanoparticles. The anti microbial activity of silver nanoparticle was performed using sewage. The approach of plant-mediated synthesis appears to be cost efficient, eco-friendly and easy methods.

  3. Coleus aromaticus leaf extract mediated synthesis of silver nanoparticles and its bactericidal activity

    NASA Astrophysics Data System (ADS)

    Vanaja, Mahendran; Annadurai, Gurusamy

    2013-06-01

    The utilization of various plant resources for the biosynthesis of metallic nanoparticles is called green nanotechnology, and it does not utilize any harmful chemical protocols. The present study reports the plant-mediated synthesis of silver nanoparticles using the plant leaf extract of Coleus aromaticus, which acts as a reducing and capping agent. The silver nanoparticles were characterized by ultraviolet visible spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and the size of the silver nanoparticles is 44 nm. The bactericidal activity of the silver nanoparticles was carried out by disc diffusion method that showed high toxicity against Bacillus subtilis and Klebsiella planticola. Biosynthesis of silver nanoparticles by using plant resources is an eco-friendly, reliable process and suitable for large-scale production. Moreover, it is easy to handle and a rapid process when compared to chemical, physical, and microbe-mediated synthesis process.

  4. Biogenic synthesis of silver nanoparticles by leaf extract of Cassia angustifolia

    NASA Astrophysics Data System (ADS)

    Amaladhas, T. Peter; Sivagami, S.; Akkini Devi, T.; Ananthi, N.; Priya Velammal, S.

    2012-12-01

    In this study Cassia angustifolia (senna) is used for the environmentally friendly synthesis of silver nanoparticles. Stable silver nanoparticles having symmetric surface plasmon resonance (SPR) band centred at 420 nm were obtained within 10 min at room temperature by treating aqueous solutions of silver nitrate with C. angustifolia leaf extract. The water soluble components from the leaves, probably the sennosides, served as both reducing and capping agents in the synthesis of silver nanoparticles. The nanoparticles were characterized using UV-Vis, Fourier transform infrared (FTIR) spectroscopic techniques and transmission electron microscopy (TEM). The nanoparticles were poly-dispersed, spherical in shape with particle size in the range 9-31 nm, the average size was found to be 21.6 nm at pH 11. The zeta potential was -36.4 mV and the particles were stable for 6 months. The crystalline phase of the nanoparticles was confirmed from the selected area diffraction pattern (SAED). The rate of formation and size of silver nanoparticles were pH dependent. Functional groups responsible for capping of silver nanoparticles were identified from the FTIR spectrum. The synthesized silver nanoparticles exhibited good antibacterial potential against Escherichia coli and Staphylococcus aureus.

  5. 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

  6. Properties of polypropylene nanocomposites containing silver nanoparticles.

    PubMed

    Jang, Myung Wook; Kim, Ju-Young; Ihn, Kyo Jin

    2007-11-01

    Silver/polypropylene (PP) nanocomposites containing silver nanoparticles smaller than 10 nm were prepared using a new synthetic method. AgNO3 crystals were dissolved into hydrophilic domain of polyoxyethylene maleate-based surfactant (PEOM), which gives self-assembly nano-structures. The AgNO3 in the nano-domains of PEOM was reduced by NaBH4 to form nanoparticles. The colloidal solutions with silver nanoparticles were diluted with ethanol and were mixed with PP pellets. Silver nanocomposites were prepared by extrusion compounding process after drying the pellets. Contents of silver nanoparticles dispersed within PP resin were changed from 100 to 1000 ppm. Formation of silver nanoparticles within PP was confirmed by UV-Vis spectroscopy and TEM. Size and distribution of dispersed silver nanoparticles were also measured by TEM. Silver/PP nanocomposites films showed not only improved thermal stability but also increased mechanical properties compared to neat PP film. Tensile properties of PP nanocomposites were largely improved compared with neat PP resin, and elongation increased also by 175% for the nanocomposites containing 1000 ppm silver nanoparticles.

  7. Photoactivable caps for reactive metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Patel, Ashish

    The synthesis and stabilization of reactive metal nanoparticles is often challenging under normal atmospheric conditions. This problem can be alleviated by capping and passivation. Our lab has focused on forming polymer coatings on the surface of reactive metal nanoparticles. We discovered a convenient and effective route for stabilization of aluminum nanoparticles (Al NPs), which uses the nascent metal core as a polymerization initiator for various organic monomers. In our previous work, we used this method to passivate the Al NPs using variety of epoxides and copolymers of epoxides and alkenes. These products have demonstrated air stability for weeks to months with little to no degradation in the active Al content. Since our previously synthesized Al NP's were not beneficial for rapid and efficient thermodynamic access to the active Al core, our goal was find polymers that could easily be photochemically activated to enhance such access. Since poly(methyl methacrylate) (PMMA) has photodegrading properties, we used PMMA as a capping agent to passivate Al NPs. In this work, we present capping and stabilization of Al NPs with PMMA, and also with 1,2-epoxyhexane/ PMMA. In our previous work, we increased the stability of Al NP capped with 1,2-epoxy-9-decene by adding 1,13-tetradecadiene as a cross-linker. Here, we used the methyl methacrylate (MMA) monomer as cross-linker for Al NP capped with 1,2-epoxy-9-decene. We have also used the MMA as capping agent. We use powder x-ray diffractametry (PXRD), differential scanning calorimetry (DSC), and thermogravity analysis (TGA) to confirm the presence of elemental Al and ATR-FTIR to confirm the presence of polymers.

  8. Synthesis of gold and silver nanoparticles using leaf extract of Perilla frutescens--a biogenic approach.

    PubMed

    Basavegowda, Nagaraj; Lee, Yong Rok

    2014-06-01

    The present investigation demonstrates a rapid biogenic approach for the synthesis of gold and silver nanoparticles using biologically active and medicinal important Perilla frutescens leaf extract as a reducing and stabilizing agent under ambient conditions. Gold and silver nanoparticles were first synthesized from Perilla frutescens leaf extract which was used as a vegetable and in traditional medicines for a long time in Korea, Japan, and China. The nanoparticles obtained were characterized by UV-vis spectroscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Surface plasmon resonance spectra of gold and silver nanoparticles were obtained at 540 and 430 nm and triangular and spherical shape respectively. TEM studies showed that the particle sizes of gold and silver nanoparticles ranges -50 nm and -40 nm respectively. X-ray diffraction studies confirm that the biosynthesized nanoparticles were crystalline gold and silver. Fourier transform infra-red spectroscopy revealed that biomolecules were involved in the synthesis and capping of the nanoparticles produced. XRD and EDX confirmed the formation of gold and silver nanoparticles. This is a simple, efficient and rapid method to synthesize gold and silver nanoparticles at room temperature without use of toxic chemicals. Obtained gold and silver nanoparticles can be used in various biomedical and biotechnological applications.

  9. Synthesis and optical properties of silver nanoparticles

    SciTech Connect

    Singh, Jaiveer; Kaurav, Netram; Choudhary, K. K.; Okram, Gunadhor S.

    2015-07-31

    The preparation of stable, uniform silver nanoparticles by reduction of silver acetate by ethylene glycol (EG) is reported in the present paper. It is a simple process of recent interest for obtaining silver nanoparticles. The samples were characterized by X-Ray diffraction (XRD), which reveals an average particle size (D) of 38 nm. The UV/Vis spectra show that an absorption peak, occurring due to surface plasmon resonance (SPR), exists at 319 nm.

  10. 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.

    2015-11-01

    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.

  11. Risk assessment of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Shipelin, V. A.; Gmoshinski, I. V.; Khotimchenko, S. A.

    2015-11-01

    Nanoparticles of metallic silver (Ag) are among the most widely used products of nanotechnology. Nanosized colloidal silver (NCS) is presented in many kinds of production as solutions of particles with diameter less than 100 nm. NCS is used in a variety of fields, including food supplements, medicines, cosmetics, packaging materials, disinfectants, water filters, and many others. Problems of toxicity and related safety of NCS for humans and environmental systems are recently overestimated basing on data of numerous toxicological studies in vitro and in vivo. The article discusses the results of current studies in recent years and the data of author's own experiments on studying the safety of NCS, that allows to move on to risk assessment of this nanomaterial presented in consumer products and environmental samples.

  12. Pithecellobium dulce mediated extra-cellular green synthesis of larvicidal silver nanoparticles.

    PubMed

    Raman, N; Sudharsan, S; Veerakumar, V; Pravin, N; Vithiya, K

    2012-10-01

    Present study reports a green chemistry approach for the biological synthesis of silver nanoparticles using the aqueous leaf extract of Pithecellobium dulce, which acts as a reducing and capping agent. It is observed that use of P. dulce leaf extract makes a fast, environmentally benign and convenient method for the synthesis of silver nanoparticles and can reduce silver ions into silver nanoparticles. Silver nanoparticles so prepared have been characterized by UV-Vis, FT-IR, X-ray diffraction, atomic force microscopy and scanning electron microscope studies. Furthermore, these nanoparticles show effective larvicidal activity against Culex quinquefasciatus (LC(50)=21.56 mg/L and r(2)=0.995) due to high surface to volume ratio.

  13. Green synthesis of silver nanoparticles using tannins

    NASA Astrophysics Data System (ADS)

    Raja, Pandian Bothi; Rahim, Afidah Abdul; Qureshi, Ahmad Kaleem; Awang, Khalijah

    2014-09-01

    Colloidal silver nanoparticles were prepared by rapid green synthesis using different tannin sources as reducing agent viz. chestnut (CN), mangrove (MG) and quebracho (QB). The aqueous silver ions when exposed to CN, MG and QB tannins were reduced which resulted in formation of silver nanoparticles. The resultant silver nanoparticles were characterized using UV-Visible, X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), and transmission electron microscopy (TEM) techniques. Furthermore, the possible mechanism of nanoparticles synthesis was also derived using FT-IR analysis. Spectroscopy analysis revealed that the synthesized nanoparticles were within 30 to 75 nm in size, while XRD results showed that nanoparticles formed were crystalline with face centered cubic geometry.

  14. 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 ...

  15. Biosynthesis of silver nanoparticles using citrus sinensis peel extract and its antibacterial activity

    NASA Astrophysics Data System (ADS)

    Kaviya, S.; Santhanalakshmi, J.; Viswanathan, B.; Muthumary, J.; Srinivasan, K.

    2011-08-01

    Biosynthesis of silver nanoparticles (AgNPs) was achieved by a novel, simple green chemistry procedure using citrus sinensis peel extract as a reducing and a capping agent. The effect of temperature on the synthesis of silver nanoparticles was carried out at room temperature (25 °C) and 60 °C. The successful formation of silver nanoparticles has been confirmed by UV-vis, FTIR, XRD, EDAX, FESEM and TEM analysis and their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa (Gram-negative), and Staphylococcus aureus (Gram-positive) has been studied. The results suggest that the synthesized AgNPs act as an effective antibacterial agent.

  16. Biogenic synthesis of silver nanoparticles using guava ( Psidium guajava) leaf extract and its antibacterial activity against Pseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Bose, Debadin; Chatterjee, Someswar

    2016-08-01

    Among the various inorganic nanoparticles, silver nanoparticles have received substantial attention in the field of antimicrobial research. For safe and biocompatible use of silver nanoparticles in antimicrobial research, the different biogenic routes are developed to synthesize silver nanoparticles that do not use toxic chemicals. Among those, to synthesize silver nanoparticles, the use of plant part extract becomes an emerging field because plant part acts as reducing as well as capping agent. For large-scale production of antibacterial silver nanoparticles using plant part, the synthesis route should be very simple, rapid, cost-effective and environment friendly based on easy availability and non-toxic nature of plant, stability and antibacterial potential of biosynthesized nanoparticles. In the present study, we report a very simple, rapid, cost-effective and environment friendly route for green synthesis of silver nanoparticles using guava ( Psidium guajava) 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 in all seasons and everywhere. The biosynthesized silver nanoparticles are characterized by UV-Vis and TEM analysis. The average particle size is 40 nm in the range of 10-90 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 that green synthesized silver nanoparticles, using guava ( Psidium guajava) leaf extract, have a potential to inhibit the growth of bacteria.

  17. 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...

  18. Plasmonic resonances of silver nano-particles

    NASA Astrophysics Data System (ADS)

    Sukharenko, Vitaly; Suslov, Anatoliy; Dorsinville, Roger

    2016-09-01

    Silver (Ag) nanoparticles (NPs) have unique optical, electrical, and thermal properties that are being incorporated into products ranging from optical communication devices and photovoltaics to biological, DNA and other chemical sensors. The optical properties of silver nanoparticles are strongly influenced by their shape, size, distribution, and surrounding environment. One of the main challenges is to maximize the coupling efficiency of incident radiation into plasmonic resonances. In this paper, we present a method to optimize the selection of mono-dispersed Ag NPs size and the wavelength of incident radiation to enhance coupling efficiency. The results are supported by experimental measurements of optical properties of mono-dispersed silver nanoparticles.

  19. Green synthesis of silver nanoparticles using marine macroalga Chaetomorpha linum

    NASA Astrophysics Data System (ADS)

    Kannan, R. Ragupathi Raja; Arumugam, R.; Ramya, D.; Manivannan, K.; Anantharaman, P.

    2013-06-01

    The present investigation demonstrates the formation of silver nanoparticles by the reduction of the aqueous silver metal ions during exposure to the seaweed ( Chaetomorpha linum) extract . The silver nanoparticles obtained were characterized by UV-visible spectrum, FTIR and scanning electron microscopy. The characteristic absorption peak at 422 nm in UV-vis spectrum confirmed the formation of silver nanoparticles. The colour intensity at 422 nm increased with duration of incubation. The size of nanoparticles synthesized varied from 3 to 44 nm with average of ~30 nm. The FTIR spectrum of C. linum extract showed peaks at 1,020, 1,112, 1,325, 1,512, 1,535, 1,610, 1,725, 1,862, 2,924, 3,330 cm-1. The vibrational bands corresponding to the bonds such as -C=C (ring), -C-O, -C-O-C and C=C (chain) are derived from water-soluble compounds such as amines, peptides, flavonoids and terpenoids present in C. linum extract. Hence, it may be inferred that these biomolecules are responsible for capping and efficient stabilization. Since no synthetic reagents were used in this investigation, it is environmentally safe and have potential for application in biomedicine and agriculture.

  20. Silver nanoparticle-E. coli colloidal interaction in water and effect on E. coli survival.

    PubMed

    Dror-Ehre, A; Mamane, H; Belenkova, T; Markovich, G; Adin, A

    2009-11-15

    Silver nanoparticles exhibit antibacterial properties via bacterial inactivation and growth inhibition. The mechanism is not yet completely understood. This work was aimed at elucidating the effect of silver nanoparticles on inactivation of Escherichia coli, by studying particle-particle interactions in aqueous suspensions. Stable, molecularly capped, positively or negatively charged silver nanoparticles were mixed at 1 to 60microgmL(-1) with suspended E. coli cells to examine their effect on inactivation of the bacteria. Gold nanoparticles with the same surfactant were used as a control, being of similar size but made up of a presumably inert metal. Log reduction of 5log(10) and complete inactivation were obtained with the silver nanoparticles while the gold nanoparticles did not show any inactivation ability. The effect of molecularly capped nanoparticles on E. coli survival was dependent on particle number. Log reduction of E. coli was associated with the ratio between the number of nanoparticles and the initial bacterial cell count. Electrostatic attraction or repulsion mechanisms in silver nanoparticle-E. coli cell interactions did not contribute to the inactivation process.

  1. Electrodeposited Silver Nanoparticles Patterned Hexagonally for SERS

    SciTech Connect

    Gu, Geun Hoi; Lee, Sue Yeone; Suh, Jung Sang

    2010-08-06

    We have fabricated hexagonally patterned silver nanoparticles for surface-enhanced Raman scattering (SERS) by electrodepositing silver on the surface of an aluminum plate prepared by completely removing the oxide from anodic aluminum oxide (AAO) templates. Even after completely removing the oxide, well-ordered hexagonal patterns, similar to the shape of graphene, remained on the surface of the aluminum plate. The borders of the hexagonal pattern protruded up to form sorts of nano-mountains at both the sides and apexes of the hexagon, with the apexes protruding even more significantly than the sides. The aluminum plate prepared by completely removing the oxide has been used in the preparation of SERS substrates by sputter-coating of gold or silver on it. Instead of sputter-coating, here we have electro-deposited silver on the aluminum plate. When silver was electro-deposited on the plate, silver nanoparticles were made along the hexagonal margins.

  2. Continuous synthesis of monodispersed silver nanoparticles using a homogeneous heating microwave reactor system.

    PubMed

    Nishioka, Masateru; Miyakawa, Masato; Kataoka, Haruki; Koda, Hidekazu; Sato, Koichi; Suzuki, Toshishige M

    2011-06-01

    Continuous synthesis of silver nanoparticles based on a polyol process was conducted using a microwave-assisted flow reactor installed in a cylindrical resonance cavity. Silver nitrate (AgNO(3)) and poly(N-vinylpyrrolidone) (PVP) dissolved in ethylene glycol were used respectively as a silver metal precursor and as a capping agent of nanoparticles. Ethylene glycol worked as the solvent and simultaneously as the reductant. Silver nanoparticles of narrow size distributions were synthesized steadily for 5 h, maintaining almost constant yield (>93%) and quality. The reaction was achieved within 2.8 s of residence time, although nanoparticles were not formed under this flow rate by conventional heating. A narrower particle size distribution was realized by the increased flow rate of the reaction solution. Nanoparticles of 9.8 nm average size with a standard deviation of 0.9 nm were synthesized at the rate of 100 ml h(-l).

  3. Mycosynthesis of silver nanoparticles bearing antibacterial activity

    PubMed Central

    Azmath, Pasha; Baker, Syed; Rakshith, Devaraju; Satish, Sreedharamurthy

    2015-01-01

    Mycosynthesis of silver nanoparticles was achieved by endophytic Colletotrichum sp. ALF2-6 inhabiting Andrographis paniculata. Well dispersed nanoparticles were characterized using UV–Visible spectrometry with maximum absorption conferring at 420 nm. FTIR analysis revealed possible biomolecules reducing the metal salt and stabilization of nanoparticles. XRD analysis depicted the diffraction intensities exhibiting between 20 and 80 °C at 2theta angle thus conferring the crystalline nature of nanoparticles. Morphological characteristic using TEM revealed the polydispersity of nanoparticles with size ranging from 20 to 50 nm. Synthesized nanoparticles exhibited bactericidal activity against selected human pathogens. Nanoparticles mode of action was carried out to reveal DNA damage activity. Thus the present investigation reports facile fabrication of silver nanoparticles from endophytic fungi. PMID:27013906

  4. Cytotoxic Potential of Silver Nanoparticles

    PubMed Central

    Zhang, Tianlu; Wang, Liming

    2014-01-01

    Silver nanoparticles (AgNPs) have been widely used in industrial, household, and healthcare-related products due to their excellent antimicrobial activity. With increased exposure of AgNPs to human beings, the risk of safety has attracted much attention from the public and scientists. In review of recent studies, we discuss the potential impact of AgNPs on individuals at the cell level. In detail, we highlight the main effects mediated by AgNPs on the cell, such as cell uptake and intracellular distribution, cytotoxicity, genotoxicity, and immunological responses, as well as some of the major factors that influence these effects in vivo and in vivo, such as dose, time, size, shape, surface chemistry, and cell type. At the end, we summarize the main influences on the cell and indicate the challenges in this field, which may be helpful for assessing the risk of AgNPs in future. PMID:24532494

  5. Antimicrobial polyethyleneimine-silver nanoparticles in a stable colloidal dispersion.

    PubMed

    Lee, Hyun Ju; Lee, Se Guen; Oh, Eun Jung; Chung, Ho Yun; Han, Sang Ik; Kim, Eun Jung; Seo, Song Yi; Ghim, Han Do; Yeum, Jeong Hyun; Choi, Jin Hyun

    2011-11-01

    Excellent colloidal stability and antimicrobial activity are important parameters for silver nanoparticles (AgNPs) in a range of biomedical applications. In this study, polyethyleneimine (PEI)-capped silver nanoparticles (PEI-AgNPs) were synthesized in the presence of sodium borohydride (NaBH(4)) and PEI at room temperature. The PEI-AgNPs had a positive zeta potential of approximately +49 mV, and formed a stable nanocolloid against agglomeration due to electrostatic repulsion. The particle size and hydrodynamic cluster size showed significant correlations with the amount of PEI and NaBH(4). PEI-AgNPs and even PEI showed excellent antimicrobial activity against Staphylococus aureus and Klebsiella pneumoniae. The cytotoxic effects of PEI and PEI-AgNPs were confirmed by an evaluation of the cell viability. The results suggest that the amount of PEI should be minimized to the level that maintains the stability of PEI-AgNPs in a colloidal dispersion.

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

    SciTech Connect

    Jagajjanani Rao, K.; Paria, Santanu

    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.

  7. Green synthesis of silver nanoparticles by Phoma glomerata.

    PubMed

    Gade, Aniket; Gaikwad, Swapnil; Duran, Nelson; Rai, Mahendra

    2014-04-01

    We report an extracellular synthesis of silver nanoparticles (SNPs) by Phoma glomerata (MTCC-2210). The fungal filtrate showed rapid synthesis in bright sunlight. The Fourier transform infrared spectroscopy (FTIR) revealed the presence of a protein cap on the silver nanoparticle, which leads to increase stability of SNP in the silver colloid. X-ray diffraction (XRD) analysis showed the number of Bragg's reflection, which are due to the face centered cubic structure of the crystalline SNPs. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), nanoparticle tracking and analysis (NTA) demonstrated the synthesis of polydispersive and spherical SNPs. Energy dispersive X-ray spectroscopy (EDX) was used to confirm the elemental composition of the sample and Zeta potential measurement was carried out to determine the stability of mycofabricated SNPs. The alkaline pH, room temperature, sunlight demonstrated optimum synthesis. Apart from the physical conditions, concentration of silver nitrate and amount of fungal filtrate affects the mycofabrication process. The study of cultural and physical parameters during the mycofabrication of SNPs by P. glomerata will be helpful in order to increase the yield of mycofabricated SNPs of desired shape and size. The process of mycofabrication of SNPs by P. glomerata was found to be eco-friendly, safe and cost-effective nature.

  8. 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 67μg/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.

  9. Complex conductivity response to silver nanoparticles in ...

    EPA Pesticide Factsheets

    The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research needs include knowledge and methods for their detection, characterization, fate, and transport. Specifically, techniques available for the direct detection and quantification of their fate and transport in the environment are limited. Their small size, high surface area to volume ratio, interfacial, and electrical properties make metallic nanoparticles, such as silver nanoparticles, good targets for detection using electrical geophysical techniques. Here we measured the complex conductivity response to silver nanoparticles in sand columns under varying moisture conditions (0–30%), nanoparticle concentrations (0–10 mg/g), lithology (presence of clay), pore water salinity (0.0275 and 0.1000 S/m), and particle size (35, 90–210 and 1500–2500 nm). Based on the Cole-Cole relaxation models we obtained the chargeability and the time constant. We demonstrate that complex conductivity can detect silver nanoparticles in porous media with the response enhanced by higher concentrations of silver nanoparticles, moisture content, ionic strength, clay content and particle diameter. Quantification of the volumetric silver nanoparticles content in the porous media can also be obtained from complex co

  10. Extracellular biosynthesis of gold and silver nanoparticles using Krishna tulsi ( Ocimum sanctum) leaf

    NASA Astrophysics Data System (ADS)

    Philip, Daizy; Unni, C.

    2011-05-01

    Aqueous extract of Ocimum sanctum leaf is used as reducing agent for the environmentally friendly synthesis of gold and silver nanoparticles. The nanoparticles were characterized using UV-vis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. These methods allow the synthesis of hexagonal gold nanoparticles having size ∼30 nm showing two surface plasmon resonance (SPR) bands by changing the relative concentration of HAuCl 4 and the extract. Broadening of SPR is observed at larger quantities of the extract possibly due to biosorption of gold ions. Silver nanoparticles with size in the range 10-20 nm having symmetric SPR band centered around 409 nm are obtained for the colloid synthesized at room temperature at a pH of 8. Crystallinity of the nanoparticles is confirmed from the XRD pattern. Biomolecules responsible for capping are different in gold and silver nanoparticles as evidenced by the FTIR spectra.

  11. Probing the effect of charge transfer enhancement in off resonance mode SERS via conjugation of the probe dye between silver nanoparticles and metal substrates.

    PubMed

    Selvakannan, Pr; Ramanathan, Rajesh; Plowman, Blake J; Sabri, Ylias M; Daima, Hemant K; O'Mullane, Anthony P; Bansal, Vipul; Bhargava, Suresh K

    2013-08-21

    The charge transfer-mediated surface enhanced Raman scattering (SERS) of crystal violet (CV) molecules that were chemically conjugated between partially polarized silver nanoparticles and optically smooth gold and silver substrates has been studied under off-resonant conditions. Tyrosine molecules were used as a reducing agent to convert silver ions into silver nanoparticles where oxidised tyrosine caps the silver nanoparticle surface with its semiquinone group. This binding through the quinone group facilitates charge transfer and results in partially oxidised silver. This establishes a chemical link between the silver nanoparticles and the CV molecules, where the positively charged central carbon of CV molecules can bind to the terminal carboxylate anion of the oxidised tyrosine molecules. After drop casting Ag nanoparticles bound with CV molecules it was found that the free terminal amine groups tend to bind with the underlying substrates. Significantly, only those CV molecules that were chemically conjugated between the partially polarised silver nanoparticles and the underlying gold or silver substrates were found to show SERS under off-resonant conditions. The importance of partial charge transfer at the nanoparticle/capping agent interface and the resultant conjugation of CV molecules to off resonant SERS effects was confirmed by using gold nanoparticles prepared in a similar manner. In this case the capping agent binds to the nanoparticle through the amine group which does not facilitate charge transfer from the gold nanoparticle and under these conditions SERS enhancement in the sandwich configuration was not observed.

  12. Green synthesis of colloidal silver nanoparticles using natural rubber latex extracted from Hevea brasiliensis

    NASA Astrophysics Data System (ADS)

    Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D.; Baffa, Oswaldo

    2011-11-01

    Colloidal silver nanoparticles were synthesized by an easy green method using thermal treatment of aqueous solutions of silver nitrate and natural rubber latex (NRL) extracted from Hevea brasiliensis. The UV-Vis spectra detected the characteristic surface plasmonic absorption band around 435 nm. Both NRL and AgNO 3 contents in the reaction medium have influence in the Ag nanoparticles formation. Lower AgNO 3 concentration led to decreased particle size. The silver nanoparticles presented diameters ranging from 2 nm to 100 nm and had spherical shape. The selected area electron diffraction (SAED) patterns indicated that the silver nanoparticles have face centered cubic (fcc) crystalline structure. FTIR spectra suggest that reduction of the silver ions are facilitated by their interaction with the amine groups from ammonia, which is used for conservation of the NRL, whereas the stability of the particles results from cis-isoprene binding onto the surface of nanoparticles. Therefore natural rubber latex extracted from H. brasiliensis can be employed in the preparation of stable aqueous dispersions of silver nanoparticles acting as a dispersing and/or capping agent. Moreover, this work provides a new method for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive.

  13. Green synthesis of colloidal silver nanoparticles using natural rubber latex extracted from Hevea brasiliensis.

    PubMed

    Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D; Baffa, Oswaldo

    2011-11-01

    Colloidal silver nanoparticles were synthesized by an easy green method using thermal treatment of aqueous solutions of silver nitrate and natural rubber latex (NRL) extracted from Hevea brasiliensis. The UV-Vis spectra detected the characteristic surface plasmonic absorption band around 435 nm. Both NRL and AgNO(3) contents in the reaction medium have influence in the Ag nanoparticles formation. Lower AgNO(3) concentration led to decreased particle size. The silver nanoparticles presented diameters ranging from 2 nm to 100 nm and had spherical shape. The selected area electron diffraction (SAED) patterns indicated that the silver nanoparticles have face centered cubic (fcc) crystalline structure. FTIR spectra suggest that reduction of the silver ions are facilitated by their interaction with the amine groups from ammonia, which is used for conservation of the NRL, whereas the stability of the particles results from cis-isoprene binding onto the surface of nanoparticles. Therefore natural rubber latex extracted from H. brasiliensis can be employed in the preparation of stable aqueous dispersions of silver nanoparticles acting as a dispersing and/or capping agent. Moreover, this work provides a new method for the synthesis of silver nanoparticles that is simple, easy to perform, pollutant free and inexpensive.

  14. Step-reduced synthesis of starch-silver nanoparticles.

    PubMed

    Raghavendra, Gownolla Malegowd; Jung, Jeyoung; Kim, Dowan; Seo, Jongchul

    2016-05-01

    In the present process, silver nanoparticles were directly synthesized in a single step by microwave irradiation of a mixture of starch, silver nitrate, and deionized water. This is different from the commonly adopted procedure for starch-silver nanoparticle synthesis in which silver nanoparticles are synthesized by preparing a starch solution as a reaction medium first. Thus, the additional step associated with the preparation of the starch solution was eliminated. In addition, no additional reducing agent was utilized. The adopted method was facile and straight forward, affording spherical silver nanoparticles with diameter below 10nm that exhibited good antibacterial activity. Further, influence of starch on the size of the silver nanoparticles was noticed.

  15. Green synthesis and characterization of silver nanoparticles using alcoholic flower extract of Nyctanthes arbortristis and in vitro investigation of their antibacterial and cytotoxic activities.

    PubMed

    Gogoi, Nayanmoni; Babu, Punuri Jayasekhar; Mahanta, Chandan; Bora, Utpal

    2015-01-01

    Here we report the synthesis of silver nanoparticles using ethanolic flower extract of Nyctanthes arbortristis, UVvisible spectra and TEM indicated the successful formation of silver nanoparticles. Crystalline nature of the silver nanoparticles was confirmed by X-ray diffraction. Fourier Transform Infra-Red Spectroscopy analysis established the capping of the synthesized silver nanoparticles with phytochemicals naturally occurring in the ethanolic flower extract of N. arbortristis. The synthesized silver nanoparticles showed antibacterial activity against the pathogenic strain of Escherichia coli MTCC 443. Furthermore, cytotoxicity of the silver nanoparticles was tested on mouse fibroblastic cell line (L929) and found to be non-toxic, which thus proved their biocompatibility. Antibacterial activity and cytotoxicity assay carried out in this study open up an important perspective of the synthesized silver nanoparticles.

  16. 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.

  17. Robust Synthesis of Ciprofloxacin-Capped Metallic Nanoparticles and Their Urease Inhibitory Assay.

    PubMed

    Nisar, Muhammad; Khan, Shujaat Ali; Qayum, Mughal; Khan, Ajmal; Farooq, Umar; Jaafar, Hawa Z E; Zia-Ul-Haq, Muhammad; Ali, Rashid

    2016-03-25

    The fluoroquinolone antibacterial drug ciprofloxacin (cip) has been used to cap metallic (silver and gold) nanoparticles by a robust one pot synthetic method under optimized conditions, using NaBH₄ as a mild reducing agent. Metallic nanoparticles (MNPs) showed constancy against variations in pH, table salt (NaCl) solution, and heat. Capping with metal ions (Ag/Au-cip) has significant implications for the solubility, pharmacokinetics and bioavailability of fluoroquinolone molecules. The metallic nanoparticles were characterized by several techniques such as ultraviolet visible spectroscopy (UV), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) methods. The nanoparticles synthesized using silver and gold were subjected to energy dispersive X-ray tests in order to show their metallic composition. The NH moiety of the piperazine group capped the Ag/Au surfaces, as revealed by spectroscopic studies. The synthesized nanoparticles were also assessed for urease inhibition potential. Fascinatingly, both Ag-cip and Au-cip NPs exhibited significant urease enzyme inhibitory potential, with IC50 = 1.181 ± 0.02 µg/mL and 52.55 ± 2.3 µg/mL, compared to ciprofloxacin (IC50 = 82.95 ± 1.62 µg/mL). MNPs also exhibited significant antibacterial activity against selected bacterial strains.

  18. Point-of-Use Removal of Cryptosporidium parvum from Water: Independent Effects of Disinfection by Silver Nanoparticles and Silver Ions and by Physical Filtration in Ceramic Porous Media.

    PubMed

    Abebe, Lydia S; Su, Yi-Hsuan; Guerrant, Richard L; Swami, Nathan S; Smith, James A

    2015-11-03

    Ceramic water filters (CWFs) impregnated with silver nanoparticles are a means of household-level water treatment. CWFs remove/deactivate microbial pathogens by employing two mechanisms: metallic disinfection and physical filtration. Herein we report on the independent effects of silver salt and nanoparticles on Cryptosporidium parvum and the removal of C. parvum by physical filtration in porous ceramic filter media. Using a murine (mouse) model, we observed that treatment of oocysts with silver nitrate and proteinate-capped silver nanoparticles resulted in decreased infection relative to untreated oocysts. Microscopy and excystation experiments were conducted to support the disinfection investigation. Heat and proteinate-capped silver-nanoparticle treatment of oocysts resulted in morphological modifications and decreased excystation rates of sporozoites. Subsequently, disk-shaped ceramic filters were produced to investigate the transport of C. parvum. Two factors were varied: sawdust size and clay-to-sawdust ratio. Five disks were prepared with combinations of 10, 16, and 20 mesh sawdust and sawdust percentage that ranged from 9 to 11%. C. parvum removal efficiencies ranged from 1.5 log (96.4%) to 2.1 log (99.2%). The 16-mesh/10% sawdust had the greatest mean reduction of 2.1-log (99.2%), though there was no statistically significant difference in removal efficiency. Based on our findings, physical filtration and silver nanoparticle disinfection likely contribute to treatment of C. parvum for silver impregnated ceramic water filters, although the contribution of physical filtration is likely greater than silver disinfection.

  19. Silver nanoparticles in the environment.

    PubMed

    Yu, Su-juan; Yin, Yong-guang; Liu, Jing-fu

    2013-01-01

    Silver nanoparticles (AgNPs) are well known for their excellent antibacterial ability and superior physical properties, and are widely used in a growing number of applications ranging from home disinfectants and medical devices to water purificants. However, with the accelerating production and introduction of AgNPs into commercial products, there is likelihood of release into the environment, which raises health and environmental concerns. This article provides a critical review of the state-of-knowledge about AgNPs, involving the history, analysis, source, fate and transport, and potential risks of AgNPs. Although great efforts have been made in each of these aspects, there are still many questions to be answered to reach a comprehensive understanding of the positive and negative effects of AgNPs. In order to fully investigate the fate and transport of AgNPs in the environment, appropriate methods for the preconcentration, separation and speciation of AgNPs should be developed, and analytical tools for the characterization and detection of AgNPs in complicated environmental samples are also urgently needed. To elucidate the environmental transformation of AgNPs, the behavior of AgNPs should be thoroughly monitored in complex environmental relevant conditions. Furthermore, additional in vivo toxicity studies should be carried out to understand the exact toxicity mechanism of AgNPs, and to predict the health effects to humans.

  20. 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 μg/mL with no significant differences of response in 5 and 10 μg/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 μg/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 μg/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.

  1. Physicochemical properties of protein-modified silver nanoparticles in seawater

    NASA Astrophysics Data System (ADS)

    Zhong, Hangyue

    2013-10-01

    This study investigated the physicochemical properties of silver nanoparticles stabilized with casein protein in seawater. UV?vis spectrometry, dynamic light scattering (DLS), and transmission electron microscopy (TEM) were applied to measure the stability of silver nanoparticles in seawater samples. The obtained results show an increased aggregation tendency of silver nanoparticles in seawater, which could be attributed its relatively high cation concentration that could neutralize the negatively charges adsorbed on the surface of silver nanoparticles and reduce the electrostatic repulsion forces between nanoparticles. Similarly, due to the surface charge screening process, the zeta potential of silver nanoparticles in seawater decreased. This observation further supported the aggregation behavior of silver nanoparticles. This study also investigated the dissolution of silver nanoparticles in seawater. Result shows that the silver nanoparticle dissolution in DI water is lower than in seawater, which is attributed to the high Cl? concentration present in seawater. As Cl? can react with silver and form soluble AgCl complex, dissolution of silver nanoparticles was enhanced. Finally, this study demonstrated that silver nanoparticles are destabilized in seawater condition. These results may be helpful in understanding the environmental risk of discharged silver nanoparticles in seawater conditions.

  2. Production of silver nanoparticles in water solution by radiation treatment

    NASA Astrophysics Data System (ADS)

    Mikhailenko, M. A.; Korobeinikov, M. V.; Bryazgin, A. A.; Tolochko, B. P.

    2017-01-01

    Radiation-chemical synthesis of silver nanoparticles was studied. The silver nanoparticles in arabinogalactan (AG) water solution are stabilized in conglomerates, it is fixed by rise of additional bands in the optical absorption spectra. Pre-radiation treatment of AG causes crosslinking and oxidation. Pretreated AG solution increases the stability of conglomerates containing silver nanoparticles in case of dilution.

  3. Genotoxicity of silver nanoparticles in Allium cepa.

    PubMed

    Kumari, Mamta; Mukherjee, A; Chandrasekaran, N

    2009-09-15

    Potential health and environmental effects of nanoparticles need to be thoroughly assessed before their widespread commercialization. Though there are few studies on cytotoxicity of nanoparticles on mammalian and human cell lines, there are hardly any reports on genotoxic and cytotoxic behavior of nanoparticles in plant cells. This study aims to investigate cytotoxic and genotoxic impacts of silver nanoparticles using root tip cells of Allium cepa as an indicator organism. A.cepa root tip cells were treated with four different concentrations (25, 20, 75, and 100 ppm) of engineered silver nanoparticles (below 100 nm size) dispersion, to study endpoints like mitotic index, distribution of cells in mitotic phases, different types of chromosomal aberrations, disturbed metaphase, sticky chromosome, cell wall disintegration, and breaks. For each concentration five sets of microscopic observations were carried out. No chromosomal aberration was observed in the control (untreated onion root tips) and the mitotic index (MI) value was 60.3%. With increasing concentration of the nanoparticles decrease in the mitotic index was noticed (60.30% to 27.62%). The different cytological effects including the chromosomal aberrations were studied in detail for the treated cells as well as control. We infer from this study that silver nanoparticles could penetrate plant system and may impair stages of cell division causing chromatin bridge, stickiness, disturbed metaphase, multiple chromosomal breaks and cell disintegration. The findings also suggest that plants as an important component of the ecosystems need to be included when evaluating the overall toxicological impact of the nanoparticles in the environment.

  4. Silver nanoparticles and their orthopaedic applications.

    PubMed

    Brennan, S A; Ní Fhoghlú, C; Devitt, B M; O'Mahony, F J; Brabazon, D; Walsh, A

    2015-05-01

    Implant-associated infection is a major source of morbidity in orthopaedic surgery. There has been extensive research into the development of materials that prevent biofilm formation, and hence, reduce the risk of infection. Silver nanoparticle technology is receiving much interest in the field of orthopaedics for its antimicrobial properties, and the results of studies to date are encouraging. Antimicrobial effects have been seen when silver nanoparticles are used in trauma implants, tumour prostheses, bone cement, and also when combined with hydroxyapatite coatings. Although there are promising results with in vitro and in vivo studies, the number of clinical studies remains small. Future studies will be required to explore further the possible side effects associated with silver nanoparticles, to ensure their use in an effective and biocompatible manner. Here we present a review of the current literature relating to the production of nanosilver for medical use, and its orthopaedic applications.

  5. Polyethyleneimine Capped Silver Nanoclusters as Efficient Antibacterial Agents.

    PubMed

    Xu, Dong; Wang, Qingyun; Yang, Tao; Cao, Jianzhong; Lin, Qinlu; Yuan, Zhiqin; Li, Le

    2016-03-18

    Development of efficient antibacterial agents is critical for human health. In the present study, we investigated the antibacterial activity of polyethyleneimine (PEI)-capped silver nanoclusters (PEI-AgNCs), based on the fact that nanoclusters normally have higher surface-to-volume ratios than traditional nanomaterials and PEI itself has a strong antimicrobial capacity. We synthesized stable silver nanoclusters by altering PEI molecular weight from 0.6 kDa to 25 kDa and characterized them by UV-Vis absorption and fluorescence spectroscopy and high resolution transmission electron microscopy. The sizes of AgNCs were around 2 nm in diameter and were little influenced by the molecular weight of PEIs. The antibacterial abilities of the four PEI-AgNCs were explored on agar plate and in liquid systems. Our results revealed that the antibacterial activity of PEI-AgNCs is excellent and the reduction of PEI molecular weight could result in the increased antibacterial capacity of PEI-AgNCs. Such proposed new materials might be useful as efficient antibacterial agents in practical clinical applications.

  6. 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.

    2015-11-01

    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.

  7. In-vitro anticancer activity of green synthesized silver nanoparticles on MCF-7 human breast cancer cells.

    PubMed

    Jang, Suk Ju; Yang, In Jun; Tettey, Clement O; Kim, Ki Mo; Shin, Heung Mook

    2016-11-01

    In recent years, green synthesis of metallic nanoparticles is a growing area of research because of their potential applications in nanomedicine. In the present study we synthesized silver nanoparticles (silver NPs) from AgNO3 using aqueous extract of Lonicera hypoglauca flower as reducing and capping agents. The synthesized silver NPs were characterized using UV-Vis spectroscopy, FTIR, SEM-ED, TEM and SAED. Silver NPs were found to be significantly toxic to MCF-7 cells via the induction of apoptosis whereas sparing normal immune system (RAW 264.7) cells.

  8. Synthesis and Characterization of L-Lysine Conjugated Silver Nanoparticles Smaller Than 10 nM

    PubMed Central

    Bonor, Jeremy; Reddy, Vandhana; Akkiraju, Hemanth; Dhurjati, Prasad; Nohe, Anja

    2015-01-01

    A rapid and convenient batch method for synthesizing lysine-conjugated silver nanoparticles of approximately 5 nm of size was developed. Nanoparticles of size less than 100 nm exhibit significant medical potential. L-Lysine demonstrates potential for therapeutic applications and silver nanoparticles are an optimal choice for drug delivery because of its intrinsic anti-platelet, anti-bacterial and anti-inflammatory capabilities. Current synthesis protocols for Lysine-capped particles under 10 nm are time consuming and tedious and allow only for the sythesis of small quantities of particles. The synthesis of Lysin-capped silver nanoparticles was based on the reaction in which AgNO3 was reduced by excess NaBH4. L-Lysine, a known essential amino acid, served as the capping agent to minimize initial aggregation. The particles were then separated by size chromatography. Capping occurred through the amide bond on L-Lysine as determined by FT-IR. The conjugation of the particle to the amide bond is important, since this leaves the amino group of Lysine open to further modifications. The particles were further characterized in regards to their shape, size and stability. Finally we demonstrated that the synthesized particles exhibit limited to no toxicity in cells, using HEK 293 cell line as a model system. Our sythesis protocol can be successfully used for scale-up and synthesis of high quantities of nanoparticles. PMID:26478827

  9. Plasmonic twinned silver nanoparticles with molecular precision

    PubMed Central

    Yang, Huayan; Wang, Yu; Chen, Xi; Zhao, Xiaojing; Gu, Lin; Huang, Huaqi; Yan, Juanzhu; Xu, Chaofa; Li, Gang; Wu, Junchao; Edwards, Alison J.; Dittrich, Birger; Tang, Zichao; Wang, Dongdong; Lehtovaara, Lauri; Häkkinen, Hannu; Zheng, Nanfeng

    2016-01-01

    Determining the structures of nanoparticles at atomic resolution is vital to understand their structure–property correlations. Large metal nanoparticles with core diameter beyond 2 nm have, to date, eluded characterization by single-crystal X-ray analysis. Here we report the chemical syntheses and structures of two giant thiolated Ag nanoparticles containing 136 and 374 Ag atoms (that is, up to 3 nm core diameter). As the largest thiolated metal nanoparticles crystallographically determined so far, these Ag nanoparticles enter the truly metallic regime with the emergence of surface plasmon resonance. As miniatures of fivefold twinned nanostructures, these structures demonstrate a subtle distortion within fivefold twinned nanostructures of face-centred cubic metals. The Ag nanoparticles reported in this work serve as excellent models to understand the detailed structure distortion within twinned metal nanostructures and also how silver nanoparticles can span from the molecular to the metallic regime. PMID:27611564

  10. Plasmonic twinned silver nanoparticles with molecular precision

    NASA Astrophysics Data System (ADS)

    Yang, Huayan; Wang, Yu; Chen, Xi; Zhao, Xiaojing; Gu, Lin; Huang, Huaqi; Yan, Juanzhu; Xu, Chaofa; Li, Gang; Wu, Junchao; Edwards, Alison J.; Dittrich, Birger; Tang, Zichao; Wang, Dongdong; Lehtovaara, Lauri; Häkkinen, Hannu; Zheng, Nanfeng

    2016-09-01

    Determining the structures of nanoparticles at atomic resolution is vital to understand their structure-property correlations. Large metal nanoparticles with core diameter beyond 2 nm have, to date, eluded characterization by single-crystal X-ray analysis. Here we report the chemical syntheses and structures of two giant thiolated Ag nanoparticles containing 136 and 374 Ag atoms (that is, up to 3 nm core diameter). As the largest thiolated metal nanoparticles crystallographically determined so far, these Ag nanoparticles enter the truly metallic regime with the emergence of surface plasmon resonance. As miniatures of fivefold twinned nanostructures, these structures demonstrate a subtle distortion within fivefold twinned nanostructures of face-centred cubic metals. The Ag nanoparticles reported in this work serve as excellent models to understand the detailed structure distortion within twinned metal nanostructures and also how silver nanoparticles can span from the molecular to the metallic regime.

  11. 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.

  12. Phytofabrication of bioinduced silver nanoparticles for biomedical applications.

    PubMed

    Ahmad, Nabeel; Bhatnagar, Sharad; Ali, Syed Salman; Dutta, Rajiv

    2015-01-01

    Synthesis of nanomaterials holds infinite possibilities as nanotechnology is revolutionizing the field of medicine by its myriad applications. Green synthesis of nanoparticles has become the need of the hour because of its eco-friendly, nontoxic, and economic nature. In this study, leaf extract of Rosa damascena was used as a bioreductant to reduce silver nitrate, leading to synthesis of silver nanoparticles (AgNPs) in a single step, without the use of any additional reducing or capping agents. The synthesized nanoparticles were characterized by the use of UV-visible spectroscopy, fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, and field emission scanning electron microscopy. Time-dependent synthesis of AgNPs was studied spectrophotometrically. Synthesized AgNPs were found to possess flower-like spherical structure where individual nanoparticles were of 16 nm in diameter, whereas the agglomerated AgNPs were in the range of 60-80 nm. These biologically synthesized AgNPs exhibited significant antibacterial activity against Gram-negative bacterial species but not against Gram-positive ones (Escherichia coli and Bacillus cereus). Anti-inflammatory and analgesic activities were studied on a Wistar rat model to gauge the impact of AgNPs for a probable role in these applications. AgNPs tested positive for both these activities, although the potency was less as compared to the standard drugs.

  13. Phytofabrication of bioinduced silver nanoparticles for biomedical applications

    PubMed Central

    Ahmad, Nabeel; Bhatnagar, Sharad; Ali, Syed Salman; Dutta, Rajiv

    2015-01-01

    Synthesis of nanomaterials holds infinite possibilities as nanotechnology is revolutionizing the field of medicine by its myriad applications. Green synthesis of nanoparticles has become the need of the hour because of its eco-friendly, nontoxic, and economic nature. In this study, leaf extract of Rosa damascena was used as a bioreductant to reduce silver nitrate, leading to synthesis of silver nanoparticles (AgNPs) in a single step, without the use of any additional reducing or capping agents. The synthesized nanoparticles were characterized by the use of UV-visible spectroscopy, fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, and field emission scanning electron microscopy. Time-dependent synthesis of AgNPs was studied spectrophotometrically. Synthesized AgNPs were found to possess flower-like spherical structure where individual nanoparticles were of 16 nm in diameter, whereas the agglomerated AgNPs were in the range of 60–80 nm. These biologically synthesized AgNPs exhibited significant antibacterial activity against Gram-negative bacterial species but not against Gram-positive ones (Escherichia coli and Bacillus cereus). Anti-inflammatory and analgesic activities were studied on a Wistar rat model to gauge the impact of AgNPs for a probable role in these applications. AgNPs tested positive for both these activities, although the potency was less as compared to the standard drugs. PMID:26648715

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

    PubMed

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

    2015-07-05

    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.

  15. 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.

  16. Bactericidal Effect of Silver Nanoparticles on Intramacrophage Brucella abortus 544

    PubMed Central

    Alizadeh, Hamed; Salouti, Mojtaba; Shapouri, Reza

    2014-01-01

    Background: Brucellosis is an infectious disease that is caused by Brucella spp. As Brucella spp. are intramacrophage pathogens, the treatment of this infection is very difficult. On the other hand, due to the side effects of the brucellosis treatment regime, it is necessary to find new antimicrobial agents against it. Objectives: The aim of this study was to investigate the antimicrobial effect of silver nanoparticles against Brucella abortus 544 in the intramacrophage condition. Materials and Methods: The antimicrobial effect of silver nanoparticles was determined by an agar well diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of silver nanoparticles against B. abortus 544 were determined by a broth macrodilution method. The effect of time on the antimicrobial activity of silver nanoparticles was analyzed. The effect of silver nanoparticles on the intramacrophage survival of B. abortus 544 was studied on mice peritoneal macrophages. Results: The well diffusion agar study showed that silver nanoparticles have an antimicrobial effect on B. abortus 544. The MIC and MBC of silver nanoparticles against B. abortus 544 were; 6 ppm and 8 ppm, respectively. The silver nanoparticles showed antibacterial effects within 40 minutes. The results of the macrophage culture indicated that silver nanoparticles have antibacterial activity against intramacrophage B. abortus 544, and the highest efficiency was observed at a concentration of 8-10 ppm of silver nanoparticles. Conclusions: The results showed that silver nanoparticles have an antimicrobial effect against intramacrophage B. abortus 544. PMID:25147682

  17. Biofabrication of silver nanoparticles using Andrographis paniculata.

    PubMed

    Kotakadi, Venkata S; Gaddam, Susmila Aparna; Subba Rao, Y; Prasad, T N V K V; Varada Reddy, A; Sai Gopal, D V R

    2014-02-12

    New and novel strategies are of recent interest in the development of silver nanoparticles. The plant extracts are eco-friendly, economical and cost effective for synthesis of nanoparticles. In this paper, we represent biofabrication of silver nanoparticles (AgNPs) using Andrographis paniculata and the synthesized AgNPs was monitored by ultra-violet visible spectroscopy (UV-Vis). The morphology and crystalline nature of AgNPs were determined from scanning electron microscopy (SEM) with Energy dispersive X-ray (EDX), X-ray diffraction patterns (XRD), Fourier transform-infrared spectroscopy (FT-IR). The size and the stability were detected by using Nanoparticle analyzer. The average size of the AgNPs was found to be 54 ± 2 nm and the Zeta potential was found to be -50.7 mV. The synthesized AgNPs have very good antifungal activity.

  18. Photobiologic-mediated fabrication of silver nanoparticles with antibacterial activity.

    PubMed

    Lee, Jeong-Ho; Lim, Jeong-Muk; Velmurugan, Palanivel; Park, Yool-Jin; Park, Youn-Jong; Bang, Keuk-Soo; Oh, Byung-Taek

    2016-09-01

    We present the simple, eco-friendly synthesis of silver nanoparticles (AgNPs) using sunlight or green, red, blue, or white LED light together with Dryopteris crassirhizoma rhizome extract (DCRE) as the reducing and capping agent. The preliminary indication of AgNP production was a color change from yellowish green to brown after light exposure in the presence of DCRE. Optimization of parameters such as pH, inoculum dose, and metal ion concentration played an important role in achieving nanoparticle production in 30min. The spectroscopic and morphological properties of AgNPs were characterized using UV-Vis spectroscopy through the presence of a characteristic surface plasmon resonance (SPR) band for AgNPs, Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), and X-ray diffraction (XRD). The FT-IR results indicated that the phytochemical present in DCRE was the probable reducing/capping agent involved in the synthesis of AgNPs, and light radiation enhanced nanoparticle production. HR-TEM revealed that the AgNPs were almost spherical with an average size of 5-60nm under all light sources. XRD studies confirmed the face cubic center (fcc) unit cell structure of AgNPs. The synthesized AgNPs showed good antimicrobial activity against Bacillus cereus and Pseudomonas aeruginosa. This study will bring a new insight in ecofriendly production of metal nanoparticles.

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

    SciTech Connect

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

    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.

  20. Silver nanoparticles decorated lipase-sensitive polyurethane micelles for on-demand release of silver nanoparticles.

    PubMed

    Su, Yuling; Zhao, Lili; Meng, Fancui; Wang, Quanxin; Yao, Yongchao; Luo, Jianbin

    2017-04-01

    In order to improve the antibacterial activities while decrease the cytotoxity of silver nanoparticles, we prepared a novel nanocomposites composed of silver nanoparticles decorated lipase-sensitive polyurethane micelles (PUM-Ag) with MPEG brush on the surface. The nanocomposite was characterized by UV-vis, TEM and DLS. UV-vis and TEM demonstrated the formation of silver nanoparticles on PU micelles and the nanoassembly remained intact without the presence of lipase. The silver nanoparticles were protected by the polymer matrix and PEG brush which show good cytocompatibility to HUVEC cells and low hemolysis. Moreover, at the presence of lipase, the polymer matrix of nanocomposites is subject to degradation and the small silver nanoparticles were released as is shown by DLS and TEM. The MIC and MBC studies showed an enhanced toxicity of the nanocomposites to both gram negative and gram positive bacteria, i.e. E. coli and S. aureus, as the result of the degradation of polymer matrix by bacterial lipase. Therefore, the nanocomposites are biocompatible to mammalian cells cells which can also lead to activated smaller silver nanoparticles release at the presence of bacteria and subsequently enhanced inhibition of bacteria growth. The satisfactory selectivity for bacteria compared to HUVEC and RBCs make PUM-Ag a promising antibacterial nanomedicine in biomedical field.

  1. Enhanced dispersibility and dispersion stability of dodecylamine-protected silver nanoparticles by dodecanethiol for ink-jet conductive inks

    NASA Astrophysics Data System (ADS)

    Zhou, Xueqin; Li, Wei; Wu, Meilan; Tang, Shen; Liu, Dongzhi

    2014-02-01

    This work studied dodecylamine-protected silver nanoparticles modified by a small amount of dodecanethiol as the co-protective agent. Contents of the dodecanethiol and the protective agent capping on the surface of silver nanoparticles were analyzed using the method of oxygen flask combustion and a thermogravimetric analysis instrument. Results of electrical property determination and transmission electron microscopy indicate that certain amount of capping dodecanethiol can slow down the spontaneous sintering process of silver nanoparticles. When capping DDT content of silver nanoparticles is 1.70 wt%, 10 wt% suspensions are stable under -18 °C and can be stored stably at room temperature as long as 120 days. Furthermore, the silver nanoparticle concentration could be increased to 20 wt% with a stable storage time of 60 days at room temperature. Finally, stable polymer-free conductive inks with the silver nanoparticle concentration of 20 wt% were produced to fabricate patterns by ink-jet printing. The resistivity of the PI-supported patterns having been annealed at 130 °C for 10 min is 7.2 μΩ cm.

  2. Interactions between silver nanoparticles and polyvinyl alcohol nanofibers

    SciTech Connect

    Chou, H. L.; Wu, C. M.; Lin, F. D.; Rick, J.

    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.

  3. Utilization of hydroxypropyl carboxymethyl cellulose in synthesis of silver nanoparticles.

    PubMed

    Abdel-Halim, E S; Alanazi, Humaid H; Al-Deyab, Salem S

    2015-04-01

    Hydroxypropyl carboxymethyl cellulose samples having varying degrees of substitution and varying degrees of polymerization were used to reduce silver nitrate to silver nanoparticles. UV spectral analysis of silver nanoparticles colloidal solution reveal that increasing the pH of the reduction solution leads to improvement in the intensity of the absorption band for silver nanoparticles, to be maximum at pH 11. The absorption peak intensity also enhanced upon prolonging the reaction duration up to 60 min. The conversion of silver ions to metallic silver nanoparticles was found to be temperature-dependent and maximum transformation occurs at 60 °C. The reduction efficiency of hydroxypropyl carboxymethyl cellulose was found to be affected by its degree of polymerization. Colloidal solutions of silver nanoparticles having concentration up to 1000 ppm can be prepared upon fixing the ratio between silver nitrate and hydroxypropyl carboxymethyl cellulose at 0.017-0.3g per each 100ml of the reduction solution.

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

    SciTech Connect

    Basavaraja, S.; Balaji, S.D.; Lagashetty, Arunkumar; Rajasab, A.H.; Venkataraman, A.

    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.

  5. 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.

  6. Size-Controlled and Optical Properties of Monodispersed Silver Nanoparticles Synthesized by the Radiolytic Reduction Method

    PubMed Central

    Saion, Elias; Gharibshahi, Elham; Naghavi, Kazem

    2013-01-01

    Size-controlled and monodispersed silver nanoparticles were synthesized from an aqueous solution containing silver nitrate as a metal precursor, polyvinyl alcohol as a capping agent, isopropyl alcohol as hydrogen and hydroxyl radical scavengers, and deionized water as a solvent with a simple radiolytic method. The average particle size decreased with an increase in dose due to the domination of nucleation over ion association in the formation of the nanoparticles by gamma reduction. The silver nanoparticles exhibit a very sharp and strong absorption spectrum with the absorption maximum λmax blue shifting with an increased dose, owing to a decrease in particle size. The absorption spectra of silver nanoparticles of various particle sizes were also calculated using a quantum physics treatment and an agreement was obtained with the experimental absorption data. The results suggest that the absorption spectrum of silver nanoparticles possibly derived from the intra-band excitations of conduction electrons from the lowest energy state (n = 5, l = 0) to higher energy states (n ≥ 6; Δl = 0, ±1; Δs = 0, ±1), allowed by the quantum numbers principle. This demonstrates that the absorption phenomenon of metal nanoparticles based on a quantum physics description could be exploited to be added into the fundamentals of metal nanoparticles and the related fields of nanoscience and nanotechnology. PMID:23579953

  7. Colored and functional silver nanoparticle-wool fiber composites.

    PubMed

    Kelly, Fern M; Johnston, James H

    2011-04-01

    Silver nanoparticles utilizing the surface plasmon resonance effect of silver have been used to color merino wool fibers as well as imparting antimicrobial and antistatic properties to them to produce a novel silver nanoparticle-wool composite material. This is accomplished by the reduction of silver ions in solution by trisodium citrate (TSC) in the presence of merino wool fibers or fabrics. The silver metal nanoparticles simultaneously bind to the amino acids of the keratin protein in the wool fibers using TSC as the linker. The colors of the resulting merino wool-silver nanoparticle composites range from yellow/brown to red/brown and then to brown/black, because of the surface plasmon resonance effect of silver, and are tuned by controlling the reduction of silver ions to silver nanoparticles to give the required particle size on the fiber surface. In addition to the surface plasmon resonance optical effects, the silver nanoparticle-wool composites exhibit effective antimicrobial activity, thus inhibiting the growth of microbes and also an increase in the electrical conductivity, imparting antistatic properties to the fibers. Therefore, silver nanoparticles function as a simultaneous colorant and antimicrobial and antistatic agent for wool. Chemical and physical characterizations of the silver nanoparticle-merino wool composite materials have been carried out using scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, synchrotron radiation X-ray diffraction, atomic absorption spectroscopy, X-ray photoelectron spectroscopy, direct-current electrical conductivity measurements, wash-fast and rub-fast tests, and antimicrobial tests.

  8. Enhanced thermal stability of phosphate capped magnetite nanoparticles

    SciTech Connect

    Muthukumaran, T.; Philip, John

    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.

  9. Differential genotoxicity mechanisms of silver nanoparticles and silver ions.

    PubMed

    Li, Yan; Qin, Taichun; Ingle, Taylor; Yan, Jian; He, Weiwei; Yin, Jun-Jie; Chen, Tao

    2017-01-01

    In spite of many reports on the toxicity of silver nanoparticles (AgNPs), the mechanisms underlying the toxicity are far from clear. A key question is whether the observed toxicity comes from the silver ions (Ag(+)) released from the AgNPs or from the nanoparticles themselves. In this study, we explored the genotoxicity and the genotoxicity mechanisms of Ag(+) and AgNPs. Human TK6 cells were treated with 5 nM AgNPs or silver nitrate (AgNO3) to evaluate their genotoxicity and induction of oxidative stress. AgNPs and AgNO3 induced cytotoxicity and genotoxicity in a similar range of concentrations (1.00-1.75 µg/ml) when evaluated using the micronucleus assay, and both induced oxidative stress by measuring the gene expression and reactive oxygen species in the treated cells. Addition of N-acetylcysteine (NAC, an Ag(+) chelator) to the treatments significantly decreased genotoxicity of Ag(+), but not AgNPs, while addition of Trolox (a free radical scavenger) to the treatment efficiently decreased the genotoxicity of both agents. In addition, the Ag(+) released from the highest concentration of AgNPs used for the treatment was measured. Only 0.5 % of the AgNPs were ionized in the culture medium and the released silver ions were neither cytotoxic nor genotoxic at this concentration. Further analysis using electron spin resonance demonstrated that AgNPs produced hydroxyl radicals directly, while AgNO3 did not. These results indicated that although both AgNPs and Ag(+) can cause genotoxicity via oxidative stress, the mechanisms are different, and the nanoparticles, but not the released ions, mainly contribute to the genotoxicity of AgNPs.

  10. Toxicity of various silver nanoparticles compared to silver ions in Daphnia magna

    PubMed Central

    2012-01-01

    Background To better understand the potential ecotoxicological impacts of silver nanoparticles released into freshwater environments, the Daphnia magna 48-hour immobilization test was used. Methods The toxicities of silver nitrate, two types of colloidal silver nanoparticles, and a suspension of silver nanoparticles were assessed and compared using standard OECD guidelines. Also, the swimming behavior and visible uptake of the nanoparticles by Daphnia were investigated and compared. The particle suspension and colloids used in the toxicity tests were well-characterized. Results The results obtained from the exposure studies showed that the toxicity of all the silver species tested was dose and composition dependent. Plus, the silver nanoparticle powders subsequently suspended in the exposure water were much less toxic than the previously prepared silver nanoparticle colloids, whereas the colloidal silver nanoparticles and AgNO3 were almost similar in terms of mortality. The silver nanoparticles were ingested by the Daphnia and accumulated under the carapace, on the external body surface, and connected to the appendages. All the silver species in this study caused abnormal swimming by the D. magna. Conclusion According to the present results, silver nanoparticles should be classified according to GHS (Globally Harmonized System of classification and labeling of chemicals) as "category acute 1" to Daphnia neonates, suggesting that the release of nanosilver into the environment should be carefully considered. PMID:22472056

  11. 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.

  12. Synthesis of gold nanoparticles and silver nanoparticles via green technology

    NASA Astrophysics Data System (ADS)

    Ahmed, Zulfiqaar; Balu, S. S.

    2012-11-01

    The proposed work describes the comparison of various methods of green synthesis for preparation of Gold and Silver nanoparticles. Pure extracts of Lemon (Citrus limon) and Tomato (Solanum lycopersicum) were mixed with aqueous solution of auric tetrachloride and silver nitrate. The resultant solutions were treated with four common techniques to assist in the reduction namely photo catalytic, thermal, microwave assisted reduction and solvo - thermal reduction. UV - Visible Spectroscopy results and STM images of the final solutions confirmed the formation of stable metallic nanoparticles. A preliminary account of the green synthesis work is presented here.

  13. Amphotericin B-conjugated biogenic silver nanoparticles as an innovative strategy for fungal infections.

    PubMed

    Ahmad, Aftab; Wei, Yun; Syed, Fatima; Tahir, Kamran; Taj, Raheela; Khan, Arif Ullah; Hameed, Muhammad Usman; Yuan, Qipeng

    2016-10-01

    New strategies are required to improve the efficacy of drugs and to treat the emerging microbial resistance. An effective strategy is to combine drugs with metal nanoparticles for the control of microbial infections and resistance. Keeping in view this fact, we developed a facile and eco-friendly protocol for the synthesis of amphotericin B-conjugated silver nanoparticles and their assessment as an antifungal agent. Phytochemicals from the aqueous extract of Maytenus royleanus and amphotericin B were used as capping agents to prepare two types of silver nanoparticles i.e. (i) biogenic silver nanoparticles (b-AgNPs) and (ii) amphotericin B-conjugated biogenic silver nanoparticles (Amp-bAgNPs). UV-Vis spectroscopy was used to detect the characteristic surface Plasmon resonance peaks (SPR) for the prepared nanoparticles (424-433 nm). High-resolution transmission electron microscopy (HRTEM) study revealed the formation of well dispersed and spherical silver nanoparticles and Amp-bAgNPs with an average particles size of 10 and 15 nm. EDX and FTIR studies confirmed the elemental composition and surface adhered biomolecules in the prepared nanoparticles respectively. Biogenic silver nanoparticles revealed low to moderate antifungal activity (4-8 mm ± 0.2), however, the amphotericin B conjugated silver nanoparticles exhibited significant activity against Candida albicans (16 mm ± 1.4) and Candida tropicalis (18 mm ± 1.5). In conclusion, the enhanced antifungal activity of the Amp-AgNPs conjugate system is due to the synergy between the antifungal activity of amphotericin B and the antimicrobial property of silver. The findings of this study suggest that the conjugated nanoparticles could be used as efficient antifungal agents and drug delivery vehicles. Furthermore, this is the first report describing the synthesis of silver nanoparticles using the aqueous extract of Maytenus royleanus and the conjugation of amphotericin B, an antifungal drug, to the

  14. Silver nanoparticles: Synthesis methods, bio-applications and properties.

    PubMed

    Abbasi, Elham; Milani, Morteza; Fekri Aval, Sedigheh; Kouhi, Mohammad; Akbarzadeh, Abolfazl; Tayefi Nasrabadi, Hamid; Nikasa, Parisa; Joo, San Woo; Hanifehpour, Younes; Nejati-Koshki, Kazem; Samiei, Mohammad

    2016-01-01

    Silver nanoparticles size makes wide range of new applications in various fields of industry. Synthesis of noble metal nanoparticles for applications such as catalysis, electronics, optics, environmental and biotechnology is an area of constant interest. Two main methods for Silver nanoparticles are the physical and chemical methods. The problem with these methods is absorption of toxic substances onto them. Green synthesis approaches overcome this limitation. Silver nanoparticles size makes wide range of new applications in various fields of industry. This article summarizes exclusively scalable techniques and focuses on strengths, respectively, limitations with respect to the biomedical applicability and regulatory requirements concerning silver nanoparticles.

  15. 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.

  16. Biosynthesis and structural characterization of silver nanoparticles from bacterial isolates

    SciTech Connect

    Zaki, Sahar; El Kady, M.F.; Abd-El-Haleem, Desouky

    2011-10-15

    Graphical abstract: In this study five bacterial isolates belong to different genera were found to be able to biosynthesize silver nanoparticles. Biosynthesis and spectral characterization are reported here. Highlights: {yields} About 300 bacterial isolates were screened for their ability to produce nanosilvers {yields} Five of them were potential candidates for synthesis of silver nanoparticles {yields} Production of silver nanoparticles was examined using UV-Vis, XRD, SEM and EDS. {yields} The presence of nanoparticles with all five bacterial isolates was confirmed. -- Abstract: This study aimed to develop a green process for biosynthesis of silver nanomaterials by some Egyptian bacterial isolates. This target was achieved by screening an in-house culture collection consists of 300 bacterial isolates for silver nanoparticle formation. Through screening process, it was observed that strains belonging to Escherichia coli (S30, S78), Bacillus megaterium (S52), Acinetobacter sp. (S7) and Stenotrophomonas maltophilia (S54) were potential candidates for synthesis of silver nanoparticles. The extracellular production of silver nanoparticles by positive isolates was investigated by UV-Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results demonstrated that UV-visible spectrum of the aqueous medium containing silver ion showed a peak at 420 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy micrograph showed formation of silver nanoparticles in the range of 15-50 nm. XRD-spectrum of the silver nanoparticles exhibited 2{theta} values corresponding to the silver nanocrystal that produce in hexagonal and cubic crystal configurations with different plane of orientation. In addition, the signals of the silver atoms were observed by EDS-spectrum analysis that confirms the presence of silver nanoparticles (Ag

  17. Synthesis of Capped AIIBVI Nanoparticles for Fluorescent Biomarkers

    NASA Astrophysics Data System (ADS)

    Rudko, Galyna; Fediv, Volodymyr; Davydenko, Igor; Gule, Evgen; Olar, Olena; Kovalchuk, Andrii

    2016-02-01

    The conditions for growing CdS nanoparticles suitable for the visualization of biological tissues were theoretically studied and experimentally checked. The optimal ranges for pH values and precursors' concentrations were determined. The applicability of the mercaptoethanol-capped nanoparticles for in vitro luminescence visualization of several cellular forms in histological specimens of human placenta has been proven.

  18. Murraya Koenigii leaf-assisted rapid green synthesis of silver and gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Philip, Daizy; Unni, C.; Aromal, S. Aswathy; Vidhu, V. K.

    2011-02-01

    A facile bottom-up 'green' and rapid synthetic route using Murraya Koenigii leaf extract as reducing and stabilizing agent produced silver nanoparticles at ambient conditions and gold nanoparticles at 373 K. The nanoparticles were characterized using UV-vis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. This method allows the synthesis of well-dispersed silver and gold nanoparticles having size ˜10 nm and ˜20 nm, respectively. Silver nanoparticles with size ˜10 nm having symmetric SPR band centered at 411 nm is obtained within 5 min of addition of the extract to the solution of AgNO 3 at room temperature. Nearly spherical gold nanoparticles having size ˜20 nm with SPR at 532 nm is obtained on adding the leaf extract to the boiling solution of HAuCl 4. Crystallinity of the nanoparticles is confirmed from the high-resolution TEM images, selected area electron diffraction (SAED) and XRD patterns. From the FTIR spectra it is found that the biomolecules responsible for capping are different in gold and silver nanoparticles. A comparison of the present work with the author's earlier reports on biosynthesis is also included.

  19. A green approach for synthesis of gold and silver nanoparticles by Leishmania sp.

    PubMed

    Ramezani, Fatemeh; Jebali, Ali; Kazemi, Bahram

    2012-11-01

    The application of microorganisms for the synthesis of metal nanoparticles as an eco-friendly and promising approach is ongoing. In this paper, an attempt has been made to investigate the capability of Leishmania sp. for synthesis of metal nanoparticles from aqueous silver and gold ions. The samples were analyzed by a UV-Vis spectroscopy and the results showed the absorbance peak values at 420 and 540 nm, respectively, for the surface plasmon resonance of silver and gold nanoparticles. The surface morphology of the nanoparticles in solution was visualized by atomic force microscope and scanning electron microscope images, which showed the production of metallic nanoparticles by this protozoan. Fourier transform infrared spectroscopy analyses confirmed the presence of different bands of protein as capping and stabilizing agent on the nanoparticles surfaces. The synthesized silver and gold nanoparticles were with dimensions ranging between 10 and 100 nm for silver and 50-100 nm for gold. These results of the present study have demonstrated the efficiency of this protozoan for synthesis of nanoparticles, by offering the merits of environmentally friendly, amenability, and time saving for large-scale production.

  20. Murraya Koenigii leaf-assisted rapid green synthesis of silver and gold nanoparticles.

    PubMed

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

    2011-02-01

    A facile bottom-up 'green' and rapid synthetic route using Murraya Koenigii leaf extract as reducing and stabilizing agent produced silver nanoparticles at ambient conditions and gold nanoparticles at 373 K. The nanoparticles were characterized using UV-vis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. This method allows the synthesis of well-dispersed silver and gold nanoparticles having size ∼10 nm and ∼20 nm, respectively. Silver nanoparticles with size ∼10 nm having symmetric SPR band centered at 411 nm is obtained within 5 min of addition of the extract to the solution of AgNO3 at room temperature. Nearly spherical gold nanoparticles having size ∼20 nm with SPR at 532 nm is obtained on adding the leaf extract to the boiling solution of HAuCl4. Crystallinity of the nanoparticles is confirmed from the high-resolution TEM images, selected area electron diffraction (SAED) and XRD patterns. From the FTIR spectra it is found that the biomolecules responsible for capping are different in gold and silver nanoparticles. A comparison of the present work with the author's earlier reports on biosynthesis is also included.

  1. Three strategies to stabilise nearly monodispersed silver nanoparticles in aqueous solution

    NASA Astrophysics Data System (ADS)

    Stevenson, Amadeus PZ; Blanco Bea, Duani; Civit, Sergi; Antoranz Contera, Sonia; Iglesias Cerveto, Alberto; Trigueros, Sonia

    2012-02-01

    Silver nanoparticles are extensively used due to their chemical and physical properties and promising applications in areas such as medicine and electronics. Controlled synthesis of silver nanoparticles remains a major challenge due to the difficulty in producing long-term stable particles of the same size and shape in aqueous solution. To address this problem, we examine three strategies to stabilise aqueous solutions of 15 nm citrate-reduced silver nanoparticles using organic polymeric capping, bimetallic core-shell and bimetallic alloying. Our results show that these strategies drastically improve nanoparticle stability by distinct mechanisms. Additionally, we report a new role of polymer functionalisation in preventing further uncontrolled nanoparticle growth. For bimetallic nanoparticles, we attribute the presence of a higher valence metal on the surface of the nanoparticle as one of the key factors for improving their long-term stability. Stable silver-based nanoparticles, free of organic solvents, will have great potential for accelerating further environmental and nanotoxicity studies. PACS: 81.07.-b; 81.16.Be; 82.70.Dd.

  2. Sunlight mediated synthesis of silver nanoparticles by a novel actinobacterium (Sinomonas mesophila MPKL 26) and its antimicrobial activity against multi drug resistant Staphylococcus aureus.

    PubMed

    Manikprabhu, Deene; Cheng, Juan; Chen, Wei; Sunkara, Anil Kumar; Mane, Sunilkumar B; Kumar, Ram; das, Mousumi; N Hozzein, Wael; Duan, Yan-Qing; Li, Wen-Jun

    2016-05-01

    Synthesis of silver nanoparticles using microorganism are many, but there are only scanty reports using actinobacteria. In the present study, the actinobacterium of the genus Sinomonas was reported to synthesis silver nanoparticles for the first time. A photo-irradiation based method was developed for the synthesis of silver nanoparticles, which includes two day old cultural supernatant of novel species Sinomonas mesophila MPKL 26 and silver nitrate solution, exposed to sunlight. The preliminary synthesis of silver nanoparticles was noted by the color change of the solution from colorless to brown; the synthesis was further confirmed using UV-visible spectroscopy which shows a peak between 400 and 450nm. Spherical shape silver nanoparticles of size range 4-50nm were synthesized, which were characterized using transmission electron microscopy. The Fourier transform infrared spectroscopy result indicates that, the metabolite produced by the novel species S. mesophila MPKL 26 was the probable reducing/capping agent involved in the synthesis of silver nanoparticles. The synthesized silver nanoparticles maintained consistent shape with respect to different time periods. The synthesized silver nanoparticles were evaluated for the antimicrobial activity against multi drug resistant Staphylococcus aureus which show good antimicrobial activity. The method developed for synthesis is easy, requires less time (20min) and produces spherical shape nanoparticles of size as small as 4nm, having good antimicrobial activity. Hence, our study enlarges the scope of actinobacteria for the rapid biosynthesis of silver nanoparticles and can be used in formulating remedies for multi drug resistant S. aureus.

  3. Biosynthesis of silver nanoparticles using Saccharomyces cerevisiae.

    PubMed

    Korbekandi, Hassan; Mohseni, Soudabeh; Mardani Jouneghani, Rasoul; Pourhossein, Meraj; Iravani, Siavash

    2016-01-01

    The objectives of this study were the biosynthesis of silver nanoparticles (NPs) by biotransformations using Saccharomyces cerevisiae and analysis of the sizes and shapes of the NPs produced. Dried and freshly cultured S. cerevisiae were used as the biocatalyst. Dried yeast synthesized few NPs, but freshly cultured yeast produced a large amount of them. Silver NPs were spherical, 2-20 nm in diameter, and the NPs with the size of 5.4 nm were the most frequent ones. NPs were seen inside the cells, within the cell membrane, attached to the cell membrane during the exocytosis, and outside of the cells.

  4. 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.

  5. Toxicogenomic responses of nanotoxicity in Daphnia magna exposed to silver nitrate and coated silver nanoparticles

    EPA Science Inventory

    Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxic...

  6. Substrate independent silver nanoparticle based antibacterial coatings.

    PubMed

    Taheri, Shima; Cavallaro, Alex; Christo, Susan N; Smith, Louise E; Majewski, Peter; Barton, Mary; Hayball, John D; Vasilev, Krasimir

    2014-05-01

    Infections arising from bacterial adhesion and colonization on medical device surfaces are a significant healthcare problem. Silver based antibacterial coatings have attracted a great deal of attention as a potential solution. This paper reports on the development of a silver nanoparticles based antibacterial surface that can be applied to any type of material surface. The silver nanoparticles were surface engineered with a monolayer of 2-mercaptosuccinic acid, which facilitates the immobilization of the nanoparticles to the solid surface, and also reduces the rate of oxidation of the nanoparticles, extending the lifetime of the coatings. The coatings had excellent antibacterial efficacy against three clinically significant pathogenic bacteria i.e. Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa. Studies with primary human fibroblast cells showed that the coatings had no cytotoxicity in vitro. Innate immune studies in cultures of primary macrophages demonstrated that the coatings do not significantly alter the level of expression of pro-inflammatory cytokines or the adhesion and viability of these cells. Collectively, these coatings have an optimal combination of properties that make them attractive for deposition on medical device surfaces such as wound dressings, catheters and implants.

  7. Bioactivity of albumins bound to silver nanoparticles.

    PubMed

    Mariam, Jessy; Sivakami, S; Kothari, D C; Dongre, P M

    2014-06-01

    The last decade has witnessed a tremendous rise in the proposed applications of nanomaterials in the field of medicine due to their very attractive physiochemical properties and novel actions such as the ability to reach previously inaccessible targets such as brain. However biological activity of functional molecules bound to nanoparticles and its physiological consequences is still unclear and hence this area requires immediate attention. The functional properties of Human Serum Albumin (HSA) and Bovine Serum Albumin (BSA) bound to silver nanoparticles (~60 nm) have been studied under physiological environment. Esterase activity, binding of drugs (warfarin and ibuprofen), antioxidant activity and copper binding by albumins was evaluated. The catalytic efficiencies of HSA and BSA diminished upon binding to silver nanoparticles. Perturbation in binding of warfarin and ibuprofen, loss of free sulphydryls, antioxidant activity and enhancement of copper binding were observed in albumins bound to nanoparticles. These alterations in functional activity of nanoparticle bound albumins which will have important consequences should be taken into consideration while using nanoparticles for diagnostic and therapeutic purposes.

  8. Synergistic effect of silver seeds and organic modifiers on the morphology evolution mechanism of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Wang, Aili; Yin, Hengbo; Ren, Min; Liu, Yuming; Jiang, Tingshun

    2008-08-01

    Triangular, truncated triangular, quadrangular, hexagonal, and net-structured silver nanoplates as well as decahedral silver nanoparticles were manipulatively prepared starting from silver nitrate and silver seeds in the presence of poly(ethylene glycol) (PEG), poly( N-vinyl pyrrolidone) (PVP), and Tween 80 at room temperature, respectively. UV-vis spectroscopy, XRD, HRTEM, SAED, and FTIR were used to illustrate the crystal growth process and to characterize the resultant silver nanoparticles. It was found that the silver seeds and organic modifiers synergistically affected the morphology evolution of the silver nanoparticles. The co-presence of silver seeds and PEG was beneficial to the formation of triangular and truncated triangular silver nanoplates; the silver seeds and PVP favored the formation of polygonal silver nanoplates; the silver seeds and Tween 80 preferred to the formation of net-structured silver plates. The morphology evolution of the resultant silver nanoparticles was correlated with the crystallinity of the silver seeds and the adsorption ability of the organic modifiers on the crystal surfaces.

  9. On the fluorescence of luminol in a silver nanoparticles complex.

    PubMed

    Voicescu, Mariana; Ionescu, Sorana

    2013-05-01

    The photophysical properties of luminol in a silver nanoparticles complex have been studied by steady-state and time resolved fluorescence spectroscopy. The effect of the serum albumin on the luminol fluorescence in the silver nanoparticles has been also investigated. It was found that the fluorescence quantum yield value of luminol in a silver nanoparticles complex is φ = 0.00407. The decrease of the average fluorescence lifetime value of the luminol in the silver nanoparticles complex was found to be low, <τ> = 1.712 ns. The luminol does not bind to the serum albumins in the presence of silver nanoparticles. The formation of a new species of luminol on silver nanoparticles is discussed. The results have influence regarding the use of luminol as an assay for bio-analytical applications.

  10. Antimicrobial activity of silver nanoparticles impregnated wound dressing

    NASA Astrophysics Data System (ADS)

    Shinde, V. V.; Jadhav, P. R.; Patil, P. S.

    2013-06-01

    In this work, silver nanoparticles were synthesized by simple wet chemical reduction method. The silver nitrate was reduced by Sodium borohydride used as reducing agent and Poly (vinyl pyrrolidone) (PVP) as stabilizing agent. The formation of silver nanoparticles was evaluated by UV-visible spectroscope and transmission electron microscope (TEM). Absorption spectrum consist two plasmon peaks at 410 and 668 nm revels the formation of anisotropic nanoparticles confirmed by TEM. The formation of silver nanoparticles was also evidenced by dynamic light scattering (DLS) study. DLS showed polydisperse silver nanoparticles with hydrodynamic size 32 nm. Protecting mechanism of PVP was manifested by FT-Raman study. Silver nanoparticles were impregnated into wound dressing by sonochemical method. The Kirby-Bauer disc diffusion methods were used for antimicrobial susceptibility testing. The antimicrobial activity of the samples has been tested against gram-negative bacterium Escherichia coli and gram-positive bacterium Staphylococcus aureus.

  11. A comparative study of silver nanoparticles synthesized by arc discharge and femtosecond laser ablation in aqueous solution

    NASA Astrophysics Data System (ADS)

    Zhang, Hongqiang; Zou, Guisheng; Liu, Lei; Li, Yong; Tong, Hao; Sun, Zhenguo; Zhou, Y. Norman

    2016-10-01

    Silver nanoparticles have been synthesized by arc discharge and femtosecond laser ablation in polyvinylpyrrolidone (PVP) aqueous solution. Both methods are the simple, cost-effective and environment-friendly way to obtain the purity silver nanoparticles. In this study, the structure, composition, morphology, size and distribution, stability, production rate and sintering properties of silver nanoparticles synthesized by both methods were compared. The spherical or pseudo-spherical silver nanoparticles were synthesized by both methods, and the diameters were below 50 nm. The arc discharge-synthesized particle distribution varied with the breakdown voltage, and laser-synthesized particle size mainly depended on the laser energy. PVP solution could cap and stabilize the silver nanoparticles by Ag-O bond, while arc discharge and laser ablation resulted in some level of PVP degradation during processing. Sliver nanoparticle colloids synthesized by both methods had the high negative values of zeta potential and exhibited the good stability. The maximum production rates of the silver nanoparticles synthesized by arc discharge and femtosecond laser ablation were 6.0 and 3.0 mg/min, respectively. In addition, the sintering properties of silver nanoparticles synthesized by both methods were also discussed.

  12. Silver nanoparticle containing silk fibroin bionanotextiles

    NASA Astrophysics Data System (ADS)

    Calamak, Semih; Aksoy, Eda Ayse; Erdogdu, Ceren; Sagıroglu, Meral; Ulubayram, Kezban

    2015-02-01

    Development of new generation bionanotextiles is an important growing field, and they have found applications as wound dressings, bandages, tissue scaffolds, etc. In this study, silver nanoparticle (AgNP) containing silk-based bionanotextiles were fabricated by electrospinning, and processing parameters were optimized and discussed in detail. AgNPs were in situ synthesized within fibroin nanofibers by UV reduction of silver ions to metallic silver. The influence of post-treatments via methanol treatment and glutaraldehyde (GA) vapor exhibited changes in the secondary structure of silk. Methanol treatment increased the tensile properties of fibers due to supported crystalline silk structure, while GA vapor promoted amorphous secondary structure. AgNP containing silk fibroin bionanotextiles had strong antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa.

  13. Isatis tinctoria mediated synthesis of amphotericin B-bound silver nanoparticles with enhanced photoinduced antileishmanial activity: A novel green approach.

    PubMed

    Ahmad, Aftab; Wei, Yun; Syed, Fatima; Khan, Shafiullah; Khan, Gul Majid; Tahir, Kamran; Khan, Arif Ullah; Raza, Muslim; Khan, Faheem Ullah; Yuan, Qiping

    2016-08-01

    After malaria, Leishmaniasis is the most prevalent infectious disease in terms of fatality and geographical distribution. The availability of a limited number of antileishmanial agents, emerging resistance to the available drugs, and the high cost of treatment complicate the treatment of leishmaniasis. To overcome these issues, critical research for new therapeutic agents with enhanced antileishmanial potential and low treatment cost is needed. In this contribution, we developed a green protocol to prepare biogenic silver nanoparticles (AgNPs) and amphotericin B-bound biogenic silver nanoparticles (AmB-AgNPs). Phytochemicals from the aqueous extract of Isatis tinctoria were used as reducing and capping agents to prepare silver nanoparticles. Amphotericin B was successfully adsorbed on the surface of biogenic silver nanoparticles. The prepared nanoparticles were characterized by various analytical techniques. UV-Visible spectroscopy was employed to detect the characteristic localized surface plasmon resonance peaks (LSPR) for the prepared nanoparticles. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) studies revealed the formation of spherical silver nanoparticles with an average particle size of 10-20nm. The cubic crystalline structure of the prepared nanoparticles was confirmed by X-ray diffraction (XRD) study. FTIR spectroscopic analysis revealed that plant polyphenolic compounds are mainly involved in metal reduction and capping. Under visible light irradiation, biogenic silver nanoparticles exhibited significant activity against Leishmania tropica with an IC50 value of 4.2μg/mL. The leishmanicidal activity of these nanoparticles was considerably enhanced by conjugation with amphotericin B (IC50=2.43μg/mL). In conclusion, the findings of this study reveal that adsorption of amphotericin B, an antileishmanial drug, to biogenic silver nanoparticles, could be a safe, more effective and economic alternative to the available

  14. 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.

  15. Antibacterial and catalytic activities of green synthesized silver nanoparticles.

    PubMed

    Bindhu, M R; Umadevi, M

    2015-01-25

    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.

  16. Multistate resistive switching in silver nanoparticle films

    PubMed Central

    Sandouk, Eric J; Gimzewski, James K; Stieg, Adam Z

    2015-01-01

    Resistive switching devices have garnered significant consideration for their potential use in nanoelectronics and non-volatile memory applications. Here we investigate the nonlinear current–voltage behavior and resistive switching properties of composite nanoparticle films comprising a large collective of metal–insulator–metal junctions. Silver nanoparticles prepared via the polyol process and coated with an insulating polymer layer of tetraethylene glycol were deposited onto silicon oxide substrates. Activation required a forming step achieved through application of a bias voltage. Once activated, the nanoparticle films exhibited controllable resistive switching between multiple discrete low resistance states that depended on operational parameters including the applied bias voltage, temperature and sweep frequency. The films’ resistance switching behavior is shown here to be the result of nanofilament formation due to formative electromigration effects. Because of their tunable and distinct resistance states, scalability and ease of fabrication, nanoparticle films have a potential place in memory technology as resistive random access memory cells. PMID:27877824

  17. Silver nanoparticles incorporated onto ordered mesoporous silica from Tollen's reagent

    NASA Astrophysics Data System (ADS)

    Zienkiewicz-Strzałka, M.; Pasieczna-Patkowska, S.; Kozak, M.; Pikus, S.

    2013-02-01

    Noble metal nanostructures supported on mesoporous silica are bridge between traditional silica adsorbents and modern catalysts. In this work the Ag/SBA-15 mesoporous materials were synthesized and characterized. Various forms of nanosilver supported on ordered mesoporous template have been successfully obtained via proposed procedures. In all synthesized materials, Tollen's reagent (diammine silver complex [Ag(NH3)2]+) was used as a silver source. Silver nanoparticles were prepared by reduction of ammoniacal silver complex by formaldehyde in the solution of stabilizer. After reduction, Ag nanoparticles could be deposited on SBA-15, or added during traditional synthesis of SBA-15 giving silver or silver chloride nanoparticles in the combination with porous silica. Silver nanostructures as nanoparticles or nanowires were also embedded onto the SBA-15 by incipient wetness impregnation of silver ions. Absorbed silver ions were next reduced under hydrogen at high temperature. There are many advantages of utilized ammoniacal silver complex as a silver source. Proposed method is capable to synthesis of various metal nanostructures with controlled composition and morphology. The silver ammonia complex is composed of two ions surrounding and protecting the central silver ion, so it is possible to obtain very small nanoparticles using simple approach without any functionalization of external and internal surface of SBA-15. This approach allows obtaining greatly small silver nanoparticles on SBA-15 (4 nm) or nanowires depending on the metal loading amount. Moreover, the colloidal silver solution prepared from Tollen's reagent, in the presence of triblock copolymer, remains stable for a long time. Reduction of Tollen's reagent to silver colloidal solution seems to be efficient, fast and interesting approach for the preparation of supported silver nanostructures Obtained samples were characterized by powder X-ray diffraction, small angle X-ray scattering (SAXS), UV

  18. Electrodeposition of silver nanoparticle arrays on transparent conductive oxides

    NASA Astrophysics Data System (ADS)

    Zhang, Dezhong; Tang, Yang; Jiang, Fuguo; Han, Zhihua; Chen, Jie

    2016-04-01

    In this paper, we present a facile method for the preparation of silver nanoparticles on aluminum-doped zinc oxide (AZO) via electrodeposition techniques at room temperature. The morphology and structure of silver nanoparticles are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), respectively. Due to localized surface plasmon resonances, as-prepared silver nanoparticles on AZO glass exhibited different reflectivity in contrast with bare AZO glass. The weighted reflection of AZO substrate increased from 10.2% to 12.8%. The high reflection property of silver nanoparticle arrays on AZO substrate might be applicable for thin film solar cells and other optoelectronics applications.

  19. "Synthesis, characterization and studies on antioxidant activity of silver nanoparticles using Elephantopus scaber leaf extract".

    PubMed

    Kharat, Sopan N; Mendhulkar, Vijay D

    2016-05-01

    The simple, eco-friendly and cost effective method of green synthesis of silver nanoparticle in the leaf extract of medicinal plant Elephantopus scaber L. is illustrated in the present work. The synthesized silver nanoparticles (AgNPs) were characterized with UV-Vis-spectroscopy, nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The UV-spectra show maximum absorbance at 435 nm, NTA analysis shows 78 nm average sizes of nanoparticles, TEM analysis indicates spherical shape of the nanoparticles with the average diameter of 50 nm. The XRD peaks at 2θ range of 30-80° correspond to (111), (200), (220), (311) reflection planes that indicate the structure of metallic silver. FTIR analysis reveals surface capping of phenolic groups. Existence of peaks in the range of 1611 to 1400 cm(-1) indicates the presence of aromatic rings in the leaf extract. The peak at 1109 cm(-1) is due to the presence of OH groups. The antioxidant activity of synthesized nanoparticles was evaluated performing DPPH assay and it is observed that the photosynthesized nanoparticle also possesses antioxidant potentials. Thus, it can be used as potential free radical scavenger. Silver particles have tremendous applications in the field of diagnostics and therapeutics. To this context, the surface coating of plant metabolite constituents has great potentials. Therefore, the present work has been undertaken to synthesize the AgNPs using leaf extract of medicinal plant, E. scaber, to characterize and access their antioxidant properties.

  20. Light controlled assembly of silver nanoparticles.

    PubMed

    Polywka, Andreas; Tückmantel, Christian; Görrn, Patrick

    2017-03-23

    Metal nanoparticles show a particularly strong interaction with light, which is the basis for nanoparticle plasmonics. One of the main goals of this emerging research field is the alignment of nanoparticles and their integration into sophisticated nanostructures providing a tailored interaction with light. This assembly of nanoparticles at well-controlled substrate sites often involves expensive technological approaches, such as electron beam lithography in order to fabricate the nanoparticle structures. Furthermore difficult numerical simulations are needed to predict their optical properties. Both requirements, fabrication and prediction, complicate a cost-efficient exploitation of nanoparticle plasmonics in optoelectronic devices. Here we show that silver nanoparticles deposited under exposure to visible light arrange in a way that the resulting structure shows an optimized interaction with that light. This way, the light not only controls the nanoparticle alignment with an estimated accuracy of well below 20 nm during deposition from the liquid phase, but also defines the optical properties of the growing structure, and therefore complicated prediction is not needed.

  1. Light controlled assembly of silver nanoparticles

    PubMed Central

    Polywka, Andreas; Tückmantel, Christian; Görrn, Patrick

    2017-01-01

    Metal nanoparticles show a particularly strong interaction with light, which is the basis for nanoparticle plasmonics. One of the main goals of this emerging research field is the alignment of nanoparticles and their integration into sophisticated nanostructures providing a tailored interaction with light. This assembly of nanoparticles at well-controlled substrate sites often involves expensive technological approaches, such as electron beam lithography in order to fabricate the nanoparticle structures. Furthermore difficult numerical simulations are needed to predict their optical properties. Both requirements, fabrication and prediction, complicate a cost-efficient exploitation of nanoparticle plasmonics in optoelectronic devices. Here we show that silver nanoparticles deposited under exposure to visible light arrange in a way that the resulting structure shows an optimized interaction with that light. This way, the light not only controls the nanoparticle alignment with an estimated accuracy of well below 20 nm during deposition from the liquid phase, but also defines the optical properties of the growing structure, and therefore complicated prediction is not needed. PMID:28332582

  2. Light controlled assembly of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Polywka, Andreas; Tückmantel, Christian; Görrn, Patrick

    2017-03-01

    Metal nanoparticles show a particularly strong interaction with light, which is the basis for nanoparticle plasmonics. One of the main goals of this emerging research field is the alignment of nanoparticles and their integration into sophisticated nanostructures providing a tailored interaction with light. This assembly of nanoparticles at well-controlled substrate sites often involves expensive technological approaches, such as electron beam lithography in order to fabricate the nanoparticle structures. Furthermore difficult numerical simulations are needed to predict their optical properties. Both requirements, fabrication and prediction, complicate a cost-efficient exploitation of nanoparticle plasmonics in optoelectronic devices. Here we show that silver nanoparticles deposited under exposure to visible light arrange in a way that the resulting structure shows an optimized interaction with that light. This way, the light not only controls the nanoparticle alignment with an estimated accuracy of well below 20 nm during deposition from the liquid phase, but also defines the optical properties of the growing structure, and therefore complicated prediction is not needed.

  3. Therapeutic gold, silver, and platinum nanoparticles.

    PubMed

    Yamada, Miko; Foote, Matthew; Prow, Tarl W

    2015-01-01

    There are an abundance of nanoparticle technologies being developed for use as part of therapeutic strategies. This review focuses on a narrow class of metal nanoparticles that have therapeutic potential that is a consequence of elemental composition and size. The most widely known of these are gold nanoshells that have been developed over the last two decades for photothermal ablation in superficial cancers. The therapeutic effect is the outcome of the thickness and diameter of the gold shell that enables fine tuning of the plasmon resonance. When these metal nanoparticles are exposed to the relevant wavelength of light, their temperature rapidly increases. This in turn induces a localized photothermal ablation that kills the surrounding tumor tissue. Similarly, gold nanoparticles have been developed to enhance radiotherapy. The high-Z nature of gold dramatically increases the photoelectric cross-section. Thus, the photoelectric effects are significantly increased. The outcome of these interactions is enhanced tumor killing with lower doses of radiation, all while sparing tissue without gold nanoparticles. Silver nanoparticles have been used for their wound healing properties in addition to enhancing the tumor-killing effects of anticancer drugs. Finally, platinum nanoparticles are thought to serve as a reservoir for platinum ions that can induce DNA damage in cancer cells. The future is bright with the path to clinical trials is largely cleared for some of the less complex therapeutic metal nanoparticle systems.

  4. Silver, gold, and alloyed silver-gold nanoparticles: characterization and comparative cell-biologic action

    NASA Astrophysics Data System (ADS)

    Mahl, Dirk; Diendorf, Jörg; Ristig, Simon; Greulich, Christina; Li, Zi-An; Farle, Michael; Köller, Manfred; Epple, Matthias

    2012-10-01

    Silver, gold, and silver-gold-alloy nanoparticles were prepared by citrate reduction modified by the addition of tannin during the synthesis, leading to a reduction in particle size by a factor of three. Nanoparticles can be prepared by this easy water-based synthesis and subsequently functionalized by the addition of either tris(3-sulfonatophenyl)phosphine or poly( N-vinylpyrrolidone). The resulting nanoparticles of silver (diameter 15-25 nm), gold (5-6 nm), and silver-gold (50:50; 10-12 nm) were easily dispersable in water and also in cell culture media (RPMI + 10 % fetal calf serum), as shown by nanoparticle tracking analysis and differential centrifugal sedimentation. High-resolution transmission electron microscopy showed a polycrystalline nature of all nanoparticles. EDX on single silver-gold nanoparticles indicated that the concentration of gold is higher inside a nanoparticle. The biologic action of the nanoparticles toward human mesenchymal stem cells (hMSC) was different: Silver nanoparticles showed a significant concentration-dependent influence on the viability of hMSC. Gold nanoparticles showed only a small effect on the viability of hMSC after 7 days. Surprisingly, silver-gold nanoparticles had no significant influence on the viability of hMSC despite the silver content. Silver nanoparticles and silver-gold nanoparticles in the concentration range of 5-20 μg mL-1 induced the activation of hMSC as indicated by the release of IL-8. In contrast, gold nanoparticles led to a reduction of the release of IL-6 and IL-8.

  5. Aquatic Toxicity Comparison of Silver Nanoparticles and Silver Nanowires.

    PubMed

    Sohn, Eun Kyung; Johari, Seyed Ali; Kim, Tae Gyu; Kim, Jin Kwon; Kim, Ellen; Lee, Ji Hyun; Chung, Young Shin; Yu, Il Je

    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.

  6. Synthesis of silver nanoparticles using DL-alanine for ESR dosimetry applications

    NASA Astrophysics Data System (ADS)

    Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D.; Nicolucci, Patricia; Baffa, Oswaldo

    2012-03-01

    The potential use of alanine for the production of nanoparticles is presented here for the first time. Silver nanoparticles were synthesized using a simple green method, namely the thermal treatment of silver nitrate aqueous solutions with DL-alanine. The latter compound was employed both as a reducing and a capping agent. Particles with average size equal to 7.5 nm, face-centered cubic crystalline structure, narrow size distribution, and spherical shape were obtained. Interaction between the silver ions present on the surface of the nanoparticles and the amine group of the DL-alanine molecule seems to be responsible for reduction of the silver ions and for the stability of the colloid. The bio-hybrid nano-composite was used as an ESR dosimeter. The amount of silver nanoparticles in the nanocomposite was not sufficient to cause considerable loss of tissue equivalency. Moreover, the samples containing nanoparticles presented increased sensitivity and reduced energetic dependence as compared with pure DL-alanine, contributing to the construction of small-sized dosimeters.

  7. Corrosion processes of triangular silver nanoparticles compared to bulk silver

    NASA Astrophysics Data System (ADS)

    Keast, V. J.; Myles, T. A.; Shahcheraghi, N.; Cortie, M. B.

    2016-02-01

    Excessive corrosion of silver nanoparticles is a significant impediment to their use in a variety of potential applications in the biosensing, plasmonic and antimicrobial fields. Here we examine the environmental degradation of triangular silver nanoparticles (AgNP) in laboratory air. In the early stages of corrosion, transmission electron microscopy shows that dissolution of the single-crystal, triangular, AgNP (side lengths 50-120 nm) is observed with the accompanying formation of smaller, polycrystalline Ag particles nearby. The new particles are then observed to corrode to Ag2S and after 21 days nearly full corrosion has occurred, but some with minor Ag inclusions remaining. In contrast, a bulk Ag sheet, studied in cross section, showed an adherent corrosion layer of only around 20-50 nm in thickness after over a decade of being exposed to ambient air. The results have implications for antibacterial properties and ecotoxicology of AgNP during corrosion as the dissolution and reformation of Ag particles during corrosion will likely be accompanied by the release of Ag+ ions.

  8. Degradation of methylene blue using biologically synthesized silver nanoparticles.

    PubMed

    Vanaja, M; Paulkumar, K; Baburaja, M; Rajeshkumar, S; Gnanajobitha, G; Malarkodi, C; Sivakavinesan, M; Annadurai, G

    2014-01-01

    Nowadays plant mediated synthesis of nanoparticles has great interest and achievement due to its eco-benign and low time consuming properties. In this study silver nanoparticles were successfully synthesized by using Morinda tinctoria leaf extract under different pH. The aqueous leaf extract was added to silver nitrate solution; the color of the reaction medium was changed from pale yellow to brown and that indicates reduction of silver ions to silver nanoparticles. Thus synthesized silver nanoparticles were characterized by UV-Vis spectrophotometer. Dispersity and morphology was characterized by scanning electron microscope (SEM); crystalline nature and purity of synthesized silver nanoparticles were revealed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). FTIR spectrum was examined to identify the effective functional molecules responsible for the reduction and stabilization of silver nanoparticles synthesized by leaf extract. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Green synthesized silver nanoparticles were effectively degrading the dye nearly 95% at 72 h of exposure time.

  9. Degradation of Methylene Blue Using Biologically Synthesized Silver Nanoparticles

    PubMed Central

    Vanaja, M.; Paulkumar, K.; Baburaja, M.; Rajeshkumar, S.; Gnanajobitha, G.; Malarkodi, C.; Sivakavinesan, M.; Annadurai, G.

    2014-01-01

    Nowadays plant mediated synthesis of nanoparticles has great interest and achievement due to its eco-benign and low time consuming properties. In this study silver nanoparticles were successfully synthesized by using Morinda tinctoria leaf extract under different pH. The aqueous leaf extract was added to silver nitrate solution; the color of the reaction medium was changed from pale yellow to brown and that indicates reduction of silver ions to silver nanoparticles. Thus synthesized silver nanoparticles were characterized by UV-Vis spectrophotometer. Dispersity and morphology was characterized by scanning electron microscope (SEM); crystalline nature and purity of synthesized silver nanoparticles were revealed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). FTIR spectrum was examined to identify the effective functional molecules responsible for the reduction and stabilization of silver nanoparticles synthesized by leaf extract. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Green synthesized silver nanoparticles were effectively degrading the dye nearly 95% at 72 h of exposure time. PMID:24772055

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

    PubMed

    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.

  11. Green synthesis and characterization of silver nanoparticles using Cydonia oblong seed extract

    NASA Astrophysics Data System (ADS)

    Zia, Faria; Ghafoor, Nida; Iqbal, Mudassir; Mehboob, Saliha

    2016-10-01

    The green synthesis of nanoparticles has emerged as a cost-effective and environmentally benign technique. The present study describes the synthesis of silver nanoparticles (Ag-NPs) using a seed extract of Cydonia oblonga. The conditions were optimized by adjusting pH, temperature, time and amount of seed extract. The nanoparticles produced were characterized by different techniques, namely UV-visible spectroscopy, Fourier transmission infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy. The formation of Ag-NPs was confirmed by UV-visible spectroscopic analysis. FTIR analysis was performed to identify the biomolecules, which played a key role in the reduction of Ag+ ions. XRD confirmed that the silver nanoparticles possessed face-centered cubic structure. The green chemistry approach has proven that Ag-NPs can be synthesized by using plant extract in which biomolecules effectively act as capping and reducing agent.

  12. Hyaluronan- and heparin-reduced silver nanoparticles with antimicrobial properties

    PubMed Central

    Kemp, Melissa M; Kumar, Ashavani; Clement, Dylan; Ajayan, Pulickel; Mousa, Shaker

    2009-01-01

    Aims Silver nanoparticles exhibit unique antibacterial properties that make these ideal candidates for biological and medical applications. We utilized a clean method involving a single synthetic step to prepare silver nanoparticles that exhibit antimicrobial activity. Materials & methods These nanoparticles were prepared by reducing silver nitrate with diaminopyridinylated heparin (DAPHP) and hyaluronan (HA) polysaccharides and tested for their efficacy in inhibiting microbial growth. Results & discussion The resulting silver nanoparticles exhibit potent antimicrobial activity against Staphylococcus aureus and modest activity against Escherichia coli. Silver–HA showed greater antimicrobial activity than silver–DAPHP, while silver–glucose nanoparticles exhibited very weak antimicrobial activity. Neither HA nor DAPHP showed activity against S. aureus or E. coli. Conclusion These results suggest that DAPHP and HA silver nanoparticles have potential in antimicrobial therapeutic applications. PMID:19505245

  13. Silver nanoparticles in X-ray biomedical applications

    NASA Astrophysics Data System (ADS)

    Mattea, Facundo; Vedelago, José; Malano, Francisco; Gomez, Cesar; Strumia, Miriam C.; Valente, Mauro

    2017-01-01

    The fluorescence of silver nanoparticles or ions can be used for detection and dose enhancement purposes in X-ray irradiation applications. This study is focused on the full integration of the chemical synthesis of silver nanoparticles suitable for dosimetric and radiological purposes with characteristics that can be exploited in radiotherapy and radiodiagnostic. A narrow size distribution and a compatible stabilizing agent is often desired in order to obtain homogeneous behaviors in nanoparticle suspension. With the method proposed in this study, nanoparticles ranging from 5 to 20 nm were obtained. The fluorescence of aqueous suspensions of silver nanoparticles has been measured experimentally and simulated with the Monte Carlo PENELOPE code for different silver concentrations and geometrical configurations. Finally, the feasibility of using these nanoparticles for the elaboration of Fricke gel dosimeters has been tested obtaining a dose enhancement when compared with the same material irradiated below the silver K-edge.

  14. Green synthesis of silver nanoparticles using white sugar.

    PubMed

    Meshram, Sachin M; Bonde, Shital R; Gupta, Indarchand R; Gade, Aniket K; Rai, Mahendra K

    2013-03-01

    Till date several methods of chemical synthesis of silver nanoparticles (AgNps) are known. Most of the protocol dealing with the chemical synthesis of AgNps involves high pressure, temperature, energy and technical skills. Thus, a method with much greener approach is the need of the hour. Accordingly, the authors have developed a method that is cost-effective, energy-efficient and easy method for the synthesis of AgNps. The AgNps were synthesised by using white sugar and sodium hydroxide (NaOH) in the presence of sunlight. These nanoparticles were characterised by visual observation, ultraviolet-visible (UV-vis) spectrophotometry, Fourier transform infrared (FTIR), nanoparticle tracking and analysis (NTA) and transmission electron microscopy (TEM). The effect of NaOH on the rate of AgNps synthesis was also studied. Formation of AgNps was primarily detected by change in colour of reaction mixture from colourless to yellow after treatment with 1 mM silver salt (AgNO3). UV-vis spectroscopy showed peak at 409 nm. NTA revealed the polydispersed nature of nanoparticles, 15-30 nm in diameter. FTIR showed the presence of gluconic acid as capping agent, which increases the stability of AgNps in the colloids. TEM demonstrated the presence of spherical AgfNps in the range of 10-25 nm. The present method confirms the synthesis of AgNps by using white sugar and NaOH. This method is simple, eco-friendly and economically sustainable, making it amenable to large-scale industrial production of AgNps.

  15. Antioxidant and anti-inflammatory activities of silver nanoparticles biosynthesized from aqueous leaves extracts of four Terminalia species

    NASA Astrophysics Data System (ADS)

    El-Rafie, Hanaa Mohamed; Abdel-Aziz Hamed, Manal

    2014-09-01

    The environmentally friendly synthesis of nanoparticles process is a revolutionary step in the field of nanotechnology. In recent years plant mediated biological synthesis of nanoparticles has been gaining importance due to its simplicity and eco-friendliness. In this study, a simple and an efficient eco-friendly approach for the biosynthesis of stable, monodisperse silver nanoparticles using aqueous extracts of four Terminalia species, namely, Terminalia catappa, Terminalia mellueri, Terminalia bentazoe and Terminalia bellerica were described. The silver nanoparticles were characterized in terms of synthesis, capping functionalities (polysaccharides, phenolics and flavonoidal compounds) and microscopic evaluation by UV-visible spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. The results showed a simple and feasible approach for obtaining stable aqueous monodispersive silver nanoparticles. Furthermore, biological activity of the biosynthesized silver nanoparticles was examined. Concerning this, dose-dependent antioxidant activity of silver nanoparticles imparted by the plant phenolic and flavonoidal components was evaluated using in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and found to be comparable to standard ascorbic acid. The same holds true for the anti-inflammatory activity where Terminalia catappa and Terminalia mellueri have a high-test inhibition percentage better than that of ascorbic acid in the carrageenan induced hind paw edema. The results also revealed that the aqueous extract of Terminallia catapa and its silver nanoparticles recorded the most potent in vivo antioxidant effect.

  16. 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...

  17. Strain specificity in antimicrobial activity of silver and copper nanoparticles.

    PubMed

    Ruparelia, Jayesh P; Chatterjee, Arup Kumar; Duttagupta, Siddhartha P; Mukherji, Suparna

    2008-05-01

    The antimicrobial properties of silver and copper nanoparticles were investigated using Escherichia coli (four strains), Bacillus subtilis and Staphylococcus aureus (three strains). The average sizes of the silver and copper nanoparticles were 3 nm and 9 nm, respectively, as determined through transmission electron microscopy. Energy-dispersive X-ray spectra of silver and copper nanoparticles revealed that while silver was in its pure form, an oxide layer existed on the copper nanoparticles. The bactericidal effect of silver and copper nanoparticles were compared based on diameter of inhibition zone in disk diffusion tests and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of nanoparticles dispersed in batch cultures. Bacterial sensitivity to nanoparticles was found to vary depending on the microbial species. Disk diffusion studies with E. coli and S. aureus revealed greater effectiveness of the silver nanoparticles compared to the copper nanoparticles. B. subtilis depicted the highest sensitivity to nanoparticles compared to the other strains and was more adversely affected by the copper nanoparticles. Good correlation was observed between MIC and MBC (r2=0.98) measured in liquid cultures. For copper nanoparticles a good negative correlation was observed between the inhibition zone observed in disk diffusion test and MIC/MBC determined based on liquid cultures with the various strains (r2=-0.75). Although strain-specific variation in MIC/MBC was negligible for S. aureus, some strain-specific variation was observed for E. coli.

  18. Active Silver Nanoparticles for Wound Healing

    PubMed Central

    Rigo, Chiara; Ferroni, Letizia; Tocco, Ilaria; Roman, Marco; Munivrana, Ivan; Gardin, Chiara; Cairns, Warren R. L.; Vindigni, Vincenzo; Azzena, Bruno; Barbante, Carlo; Zavan, Barbara

    2013-01-01

    In this preliminary study, the silver nanoparticle (Ag NP)-based dressing, Acticoat™ Flex 3, has been applied to a 3D fibroblast cell culture in vitro and to a real partial thickness burn patient. The in vitro results show that Ag NPs greatly reduce mitochondrial activity, while cellular staining techniques show that nuclear integrity is maintained, with no signs of cell death. For the first time, transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS) analyses were carried out on skin biopsies taken from a single patient during treatment. The results show that Ag NPs are released as aggregates and are localized in the cytoplasm of fibroblasts. No signs of cell death were observed, and the nanoparticles had different distributions within the cells of the upper and lower dermis. Depth profiles of the Ag concentrations were determined along the skin biopsies. In the healed sample, most of the silver remained in the surface layers, whereas in the unhealed sample, the silver penetrated more deeply. The Ag concentrations in the cell cultures were also determined. Clinical observations and experimental data collected here are consistent with previously published articles and support the safety of Ag NP-based dressing in wound treatment. PMID:23455461

  19. Synthesis of silver nanoparticles in melts of amphiphilic polyesters

    NASA Astrophysics Data System (ADS)

    Vasylyev, S.; Damm, C.; Segets, D.; Hanisch, M.; Taccardi, N.; Wasserscheid, P.; Peukert, W.

    2013-03-01

    The current work presents a one-step procedure for the synthesis of amphiphilic silver nanoparticles suitable for production of silver-filled polymeric materials. This solvent free synthesis via reduction of Tollens’ reagent as silver precursor in melts of amphiphilic polyesters consisting of hydrophilic poly(ethylene glycol) blocks and hydrophobic alkyl chains allows the production of silver nanoparticles without any by-product formation. This makes them especially interesting for the production of medical devices with antimicrobial properties. In this article the influences of the chain length of the hydrophobic block in the amphiphilic polyesters and the process temperature on the particle size distribution (PSD) and the stability of the particles against agglomeration are discussed. According to the results of spectroscopic and viscosimetric investigations the silver precursor is reduced to elemental silver nanoparticles by a single electron transfer process from the poly(ethylene glycol) chain to the silver ion.

  20. Study of ecotoxicity of silver nanoparticles using daphnids

    NASA Astrophysics Data System (ADS)

    Kustov, L. M.; Abramenko, N. B.

    2016-12-01

    Silver nanoparticles have been prepared and tested for their ecotoxicity using daphnids as a hydrobiotic test. The toxicity was supposed to originate from Ag+ ions released into the aqueous solution. Also, the toxicity of the stabilizing agent was found to be comparable to that of silver nanoparticles.

  1. Chitin membranes containing silver nanoparticles for wound dressing application.

    PubMed

    Singh, Rita; Singh, Durgeshwer

    2014-06-01

    Silver nanoparticles are gaining importance as an antimicrobial agent in wound dressings. Chitin is a biopolymer envisioned to promote rapid dermal regeneration and accelerate wound healing. This study was focused on the evaluation of chitin membranes containing silver nanoparticles for use as an antimicrobial wound dressing. Silver nanoparticles were synthesised by gamma irradiation at doses of 50 kGy in the presence of sodium alginate as stabiliser. The UV-Vis absorption spectra of nanoparticles exhibited an absorption band at 415-420 nm, which is the typical plasmon resonance band of silver nanoparticles. The peaks in the X-ray diffraction (XRD) pattern are in agreement with the standard values of the face-centred cubic silver. Transmission electron microscopy (TEM) images indicate silver nanoparticles with spherical morphology and small particle size in the range of 3-13 nm. In vitro antimicrobial tests were performed using Pseudomonas aeruginosa and Staphylococcus aureus to determine the antimicrobial efficiency of the chitin membranes containing 30, 50, 70 and 100 ppm nanosilver. No viable counts for P. aeruginosa were detected with 70 ppm silver nanoparticles dressing after 1-hour exposure. A 2-log reduction in viable cell count was observed for S. aureus after 1 hour and a 4-log reduction after 6 hours with 100 ppm nanosilver chitin membranes. This study demonstrates the antimicrobial capability of chitin membranes containing silver nanoparticles. The chitin membranes with 100 ppm nanosilver showed promising antimicrobial activity against common wound pathogens.

  2. 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...

  3. Study of ecotoxicity of silver nanoparticles using algae

    NASA Astrophysics Data System (ADS)

    Kustov, L. M.; Abramenko, N. B.

    2016-11-01

    Silver nanoparticles have been prepared and tested for their ecotoxicity using Chlorella vulgaris Beijer. algae as a hydrobiotic test organism and a photometric method of control. The toxicity was supposed to originate from Ag+ ions released into the aqueous solution. Also, the toxicity of the stabilizing agent was found to be comparable to that of silver nanoparticles.

  4. Facile biofunctionalization of silver nanoparticles for enhanced antibacterial properties, endotoxin removal, and biofilm control

    PubMed Central

    Lambadi, Paramesh Ramulu; Sharma, Tarun Kumar; Kumar, Piyush; Vasnani, Priyanka; Thalluri, Sitaramanjaneya Mouli; Bisht, Neha; Pathania, Ranjana; Navani, Naveen Kumar

    2015-01-01

    Infectious diseases cause a huge burden on healthcare systems worldwide. Pathogenic bacteria establish infection by developing antibiotic resistance and modulating the host’s immune system, whereas opportunistic pathogens like Pseudomonas aeruginosa adapt to adverse conditions owing to their ability to form biofilms. In the present study, silver nanoparticles were biofunctionalized with polymyxin B, an antibacterial peptide using a facile method. The biofunctionalized nanoparticles (polymyxin B-capped silver nanoparticles, PBSNPs) were assessed for antibacterial activity against multiple drug-resistant clinical strain Vibrio fluvialis and nosocomial pathogen P. aeruginosa. The results of antibacterial assay revealed that PBSNPs had an approximately 3-fold higher effect than the citrate-capped nanoparticles (CSNPs). Morphological damage to the cell membrane was followed by scanning electron microscopy, testifying PBSNPs to be more potent in controlling the bacterial growth as compared with CSNPs. The bactericidal effect of PBSNPs was further confirmed by Live/Dead staining assays. Apart from the antibacterial activity, the biofunctionalized nanoparticles were found to resist biofilm formation. Electroplating of PBSNPs onto stainless steel surgical blades retained the antibacterial activity against P. aeruginosa. Further, the affinity of polymyxin for endotoxin was exploited for its removal using PBSNPs. It was found that the prepared nanoparticles removed 97% of the endotoxin from the solution. Such multifarious uses of metal nanoparticles are an attractive means of enhancing the potency of antimicrobial agents to control infections. PMID:25834431

  5. Facile biofunctionalization of silver nanoparticles for enhanced antibacterial properties, endotoxin removal, and biofilm control.

    PubMed

    Lambadi, Paramesh Ramulu; Sharma, Tarun Kumar; Kumar, Piyush; Vasnani, Priyanka; Thalluri, Sitaramanjaneya Mouli; Bisht, Neha; Pathania, Ranjana; Navani, Naveen Kumar

    2015-01-01

    Infectious diseases cause a huge burden on healthcare systems worldwide. Pathogenic bacteria establish infection by developing antibiotic resistance and modulating the host's immune system, whereas opportunistic pathogens like Pseudomonas aeruginosa adapt to adverse conditions owing to their ability to form biofilms. In the present study, silver nanoparticles were biofunctionalized with polymyxin B, an antibacterial peptide using a facile method. The biofunctionalized nanoparticles (polymyxin B-capped silver nanoparticles, PBSNPs) were assessed for antibacterial activity against multiple drug-resistant clinical strain Vibrio fluvialis and nosocomial pathogen P. aeruginosa. The results of antibacterial assay revealed that PBSNPs had an approximately 3-fold higher effect than the citrate-capped nanoparticles (CSNPs). Morphological damage to the cell membrane was followed by scanning electron microscopy, testifying PBSNPs to be more potent in controlling the bacterial growth as compared with CSNPs. The bactericidal effect of PBSNPs was further confirmed by Live/Dead staining assays. Apart from the antibacterial activity, the biofunctionalized nanoparticles were found to resist biofilm formation. Electroplating of PBSNPs onto stainless steel surgical blades retained the antibacterial activity against P. aeruginosa. Further, the affinity of polymyxin for endotoxin was exploited for its removal using PBSNPs. It was found that the prepared nanoparticles removed 97% of the endotoxin from the solution. Such multifarious uses of metal nanoparticles are an attractive means of enhancing the potency of antimicrobial agents to control infections.

  6. Optimization and antioxidant properties of phytosynthesized silver nanoparticles using Dianthus caryophyllus L. (carnation)

    NASA Astrophysics Data System (ADS)

    Rachna, Saharan, Baljeet Singh; Yadav, M. S.; Sharma, Nisha

    2016-05-01

    In the recent years, silver nanoparticles have been the focus of Nanobiotechnology due to their unique interdisciplinary applications in the field of biomedicals, material diagnostics, optics and chemistry. A wide set of physical and chemical methods have been devised for providing the effective and efficient synthesis procedure of silver nanoparticles (AgNPs) but are somehow expensive and involve toxic substances. There is a critical need to develop reliable and eco-friendly process for synthesizing silver nanoparticles. In the present investigation, a simple and cost-effective green approach has been utilized for the production of stable silver nanoparticles by employing Dianthus caryophyllus flower extract. Different optimization conditions were checked for extract capped AgNPs and characterized by UV-Visible spectrophotometer. The optimum 0.02 dilution of extract found efficient to reduce 4 mM silver ions in the ratio 60:40 at pH 9. The antioxidant potential of the resultant AgNPs was observed using Hydrogen peroxide assay. There was an increasing trend of antioxidant property with increasing concentration. This potential of these photosynthesized AgNPs makes them reliable for good cause of society, mainly in therapeutic and biomedical applications.

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

    PubMed Central

    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

  8. 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.

  9. Pseudomonas deceptionensis DC5-mediated synthesis of extracellular silver nanoparticles.

    PubMed

    Jo, Jae H; Singh, Priyanka; Kim, Yeon J; Wang, Chao; Mathiyalagan, Ramya; Jin, Chi-Gyu; Yang, Deok C

    2016-09-01

    The biological synthesis of metal nanoparticles is of great interest in the field of nanotechnology. The present work highlights the extracellular biological synthesis of silver nanoparticles using Pseudomonas deceptionensis DC5. The particles were synthesized in the culture supernatant within 48 h of incubation. Extracellular synthesis of silver nanoparticles in the culture supernatant was confirmed by ultraviolet-visible spectroscopy, which showed the absorption peak at 428 nm, and also under field emission transmission electron microscopy which displayed the spherical shape. In addition, the particles were characterized by X-ray diffraction spectroscopy, which corresponds to the crystalline nature of nanoparticles, and energy-dispersive X-ray analysis which exhibited the intense peak at 3 keV, resembling the silver nanoparticles. Further, the synthesized nanoparticles were examined by elemental mapping which displayed the dominance of the silver element in the synthesized product, and dynamic light scattering which showed the distribution of silver nanoparticles with respect to intensity, volume, and number of particles. Moreover, the silver nanoparticles have been found to be quite active in antimicrobial activity and biofilm inhibition activity against pathogenic microorganisms. Thus, the present work emphasized the prospect of using the P. deceptionensis DC5 to achieve the extracellular synthesis of silver nanoparticles in a facile and environmental manner.

  10. Evaluation of green synthesized silver nanoparticles against parasites.

    PubMed

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

    2011-06-01

    Green nanoparticle synthesis has been achieved using environmentally acceptable plant extract and eco-friendly reducing and capping agents. The present study was based on assessments of the antiparasitic activities to determine the efficacies of 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 (Diptera: Culicidae), and Rhipicephalus (Boophilus) microplus Canestrini (Acari: Ixodidae). Parasite larvae were exposed to varying concentrations of aqueous extract of M. pudica and synthesized AgNPs for 24 h. AgNPs were rapidly synthesized using the leaf extract of M. pudica and the formation of nanoparticles was observed within 6 h. The results recorded from UV-vis spectrum, Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy support the biosynthesis and characterization of AgNPs. The maximum efficacy was observed in synthesized AgNPs against the larvae of A. subpictus, C. quinquefasciatus, and R. microplus (LC(50) = 13.90, 11.73, and 8.98 mg/L, r (2) = 0.411, 0.286, and 0.479), respectively. This is the first report on antiparasitic activity of the plant extract and synthesized AgNPs.

  11. Synthesis and applications of novel silver nanoparticle structures

    NASA Astrophysics Data System (ADS)

    Dukes, Kyle

    The field of nanotechnology is rapidly expanding across disciplines as each new development is realized. New exciting technologies are being driven by advances in the application of nanotechnology; including biochemical, optical, and semiconductors research. This thesis will focus on the use of silver nanoparticles as optical labels on cells, methods of forming different small structures of silver nanoparticles, as well as the use of silver nanoparticles in the development of a photovoltaic cell. Silver nanoparticles have been modified with self-assembled monolayers of hydroxyl-terminated long chain thiols and encapsulated with a silica shell. The resulting core-shell nanoparticles were used as optical labels for cell analysis using flow cytometry and microscopy. The excitation of plasmon resonances in nanoparticles results in strong depolarized scattering of visible light permitting detection at the single nanoparticle level. The nanoparticles were modified with neutravidin via epoxide-azide coupling chemistry and biotinylated antibodies targeting cell surface receptors were bound to the nanoparticle surface. The nanoparticle labels exhibited long-term stability under physiological conditions without aggregation or silver ion leaching. Labeled cells exhibited two orders of magnitude enhancement of the scattering intensity compared to unlabeled cells. Dimers of silver nanoparticles have been fabricated by first immobilizing a monolayer of single silver nanoparticles onto poly(4-vinylpyridine) covered glass slides. The monolayer was then exposed to adenine, which has two amines which will bind to silver. The nanoparticle monolayer, now modified with adenine, is exposed to a second suspension of nanoparticles which will bind with the amine modified monolayer. Finally, a thin silica shell is formed about the structure via solgel chemistry to prevent dissolution or aggregation upon sonication/striping. Circular arrays of silver nanoparticels are developed using a

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

    SciTech Connect

    Lin, Jian-Yang; Hsueh, Yu-Lee; Huang, Jung-Jie

    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 μm). 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 μm, respectively. • Silver nanowire film with high transmittance (>85%) and low sheet resistance (<110 Ω/sq)

  13. Silver nanoparticles: synthesis, properties, and therapeutic applications

    PubMed Central

    Wei, Liuya; Lu, Jingran; Xu, Huizhong; Patel, Atish; Chen, Zhe-Sheng; Chen, Guofang

    2014-01-01

    Silver nanoparticles (AgNPs) have been widely used in biomedical fields because of their intrinsic therapeutic properties. Here, we introduce methods of synthesizing AgNPs and discuss their physicochemical, localized surface plasmon resonance (LSPR) and toxicity properties. We also review the impact of AgNPs on human health and the environment along with the underlying mechanisms. More importantly, we highlight the newly emerging applications of AgNPs as antiviral agents, photosensitizers and/or radiosensitizers, and anticancer therapeutic agents in the treatment of leukemia, breast cancer, hepatocellular carcinoma, lung cancer, and skin and/or oral carcinoma. PMID:25543008

  14. Circular dichroism study of chiral biomolecules conjugated with silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Li, Taihua; Park, Hyun Gyu; Lee, Hee-Seung; Choi, Seong-Ho

    2004-10-01

    Chiral biomolecules conjugated with silver nanoparticles were investigated by circular dichroism (CD) spectroscopy. Silver nanoparticles were prepared by the citrate reduction method and were characterized by UV spectroscopy and TEM. Conjugation of thiol group-containing biomolecules, such as cysteine, glutathione and penicillamine, with silver nanoparticles resulted in the generation of new characteristic CD signals in the region of 240-400 nm, whereas no CD signal changes were found with lysine or glutamine. Association through hydrogen bonding among the biomolecules is considered to be essential for CD signal generation, which was confirmed by experiment with cysteine methyl ester. Interestingly, Au nanoparticles were not found to generate CD signals in the wavelength region tested, indicating that this phenomenon is a unique feature of silver nanoparticles, distinguished from gold nanoparticles.

  15. Synthesis and characterization of bactericidal silver nanoparticles using cultural filtrate of simulated microgravity grown Klebsiella pneumoniae.

    PubMed

    Kalpana, Duraisamy; Lee, Yang Soo

    2013-03-05

    Silver nanoparticles were synthesized by biological method using cultural filtrate of Klebsiella pneumoniae cultured under simulated microgravity and silver nitrate solution as precursor. The nanoparticles exhibited typical plasmon absorption maximum of silver nanoparticles between 405 and 407 nm. Spherical silver nanoparticles were found to have size between 15 and 37 nm by TEM analysis. XRD pattern corresponding to planes (111), (200), (220) (311) revealed the crystalline nature of the biosynthesized silver nanoparticles. FTIR spectrum proposed stabilization of silver nanoparticles by the protein molecules present in the cultural filtrate. The silver nanoparticles exhibited high bactericidal activity against Salmonella enterica, Escherichia coli and moderate bactericidal activity against Streptococcus pyogenes.

  16. 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.

  17. Targeted silver nanoparticles for ratiometric cell phenotyping

    NASA Astrophysics Data System (ADS)

    Willmore, Anne-Mari A.; Simón-Gracia, Lorena; Toome, Kadri; Paiste, Päärn; Kotamraju, Venkata Ramana; Mölder, Tarmo; Sugahara, Kazuki N.; Ruoslahti, Erkki; Braun, Gary B.; Teesalu, Tambet

    2016-04-01

    Affinity targeting is used to deliver nanoparticles to cells and tissues. For efficient targeting, it is critical to consider the expression and accessibility of the relevant receptors in the target cells. Here, we describe isotopically barcoded silver nanoparticles (AgNPs) as a tool for auditing affinity ligand receptors in cells. Tumor penetrating peptide RPARPAR (receptor: NRP-1) and tumor homing peptide GKRK (receptor: p32) were used as affinity ligands on the AgNPs. The binding and uptake of the peptide-functionalized AgNPs by cultured PPC-1 prostate cancer and M21 melanoma cells was dependent on the cell surface expression of the cognate peptide receptors. Barcoded peptide-functionalized AgNPs were synthesized from silver and palladium isotopes. The cells were incubated with a cocktail of the barcoded nanoparticles [RPARPAR (R), GKRK (K), and control], and cellular binding and internalization of each type of nanoparticle was assessed by inductively coupled plasma mass spectrometry. The results of isotopic analysis were in agreement with data obtained using optical methods. Using ratiometric measurements, we were able to classify the PPC-1 cell line as mainly NRP-1-positive, with 75 +/- 5% R-AgNP uptake, and the M21 cell line as only p32-positive, with 89 +/- 9% K-AgNP uptake. The isotopically barcoded multiplexed AgNPs are useful as an in vitro ratiometric phenotyping tool and have potential uses in functional evaluation of the expression of accessible homing peptide receptors in vivo.Affinity targeting is used to deliver nanoparticles to cells and tissues. For efficient targeting, it is critical to consider the expression and accessibility of the relevant receptors in the target cells. Here, we describe isotopically barcoded silver nanoparticles (AgNPs) as a tool for auditing affinity ligand receptors in cells. Tumor penetrating peptide RPARPAR (receptor: NRP-1) and tumor homing peptide GKRK (receptor: p32) were used as affinity ligands on the AgNPs. The

  18. Silver nanoparticles-coated glass frits for silicon solar cells

    NASA Astrophysics Data System (ADS)

    Li, Yingfen; Gan, Weiping; Li, Biyuan

    2016-04-01

    Silver nanoparticles-coated glass frit composite powders for silicon solar cells were prepared by electroless plating. Silver colloids were used as the activating agent of glass frits. The products were characterized by X-ray diffraction, scanning electron microscopy, and differential scanning calorimetry. The characterization results indicated that silver nanoparticles with the melting temperature of 838 °C were uniformly deposited on glass frit surface. The particle size of silver nanoparticles could be controlled by adjusting the [Ag(NH3)2]NO3 concentration. The as-prepared composite powders were applied in the front side metallization of silicon solar cells. Compared with those based on pure glass frits, the solar cells containing the composite powders had the denser silver electrodes and the better silver-silicon ohmic contacts. Furthermore, the photovoltaic performances of solar cells were improved after the electroless plating.

  19. Biological Mechanism of Silver Nanoparticle Toxicity

    NASA Astrophysics Data System (ADS)

    Armstrong, Najealicka Nicole

    Silver nanoparticles (AgNPs), like almost all nanoparticles, are potentially toxic beyond a certain concentration because the survival of the organism is compromised due to scores of pathophysiological abnormalities above that concentration. However, the mechanism of AgNP toxicity remains undetermined. Instead of applying a toxic dose, these investigations were attempted to monitor the effects of AgNPs at a non-lethal concentration on wild type Drosophila melanogaster by exposing them to nanoparticles throughout their development. All adult flies raised in AgNP doped food indicated that of not more than 50 mg/L had no negative influence on median survival; however, these flies appeared uniformly lighter in body color due to the loss of melanin pigments in their cuticle. Additionally, fertility and vertical movement ability were compromised after AgNP feeding. The determination of the amount of free ionic silver (Ag+) indicated that the observed biological effects had resulted from the AgNPs and not from Ag+. Biochemical analysis suggests that the activity of copper dependent enzymes, namely tyrosinase and Cu-Zn superoxide dismutase, were decreased significantly following the consumption of AgNPs, despite the constant level of copper present in the tissue. Furthermore, copper supplementation restored the loss of AgNP induced demelanization, and the reduction of functional Ctr1 in Ctr1 heterozygous mutants caused the flies to be resistant to demelanization. Consequently, these studies proposed a mechanism whereby consumption of excess AgNPs in association with membrane bound copper transporter proteins cause sequestration of copper, thus creating a condition that resembles copper starvation. This model also explained the cuticular demelanization effect resulting from AgNP since tyrosinase activity is essential for melanin biosynthesis. Finally, these investigations demonstrated that Drosophila, an established genetic model system, can be well utilized for further

  20. Metal-metal bonding using silver/copper nanoparticles

    NASA Astrophysics Data System (ADS)

    Kobayashi, Y.; Maeda, T.; Yasuda, Y.; Morita, T.

    2016-08-01

    A method for producing nanoparticles composed of silver and copper and a metal-metal bonding technique using the silver/copper nanoparticles are proposed. The method consists of three steps. First, copper oxide nanoparticles are produced by mixing Cu(NO3)2 aqueous solution and NaOH aqueous solution. Second, copper metal nanoparticles are fabricated by reducing the copper oxide nanoparticles with hydrazine in the presence of poly(vinylpyrrolidone) (PVP). Third, silver/copper nanoparticles are synthesized by reducing Ag+ ions with hydrazine in the presence of the copper metal nanoparticles. Initial concentrations in the final silver/copper particle colloid, composed of 0.0075 M Cu2+, 0.0025 M Ag+, 1.0 g/L PVP, and 0.6 M hydrazine, produced silver/copper nanoparticles with an average size of 49 nm and a crystal size of 16.8 nm. Discs of copper metal were successfully bonded by the silver/copper nanoparticles under annealing at 400 °C and pressurizing at 1.2 MPa for 5 min in not only hydrogen gas but also nitrogen gas. The shear force required to separate the bonded discs was 22.3 MPa for the hydrogen gas annealing and 14.9 MPa for the nitrogen gas annealing (namely, 66.8 % of that for hydrogen gas annealing).

  1. Optimization of Biological Synthesis of Silver Nanoparticles using Fusarium oxysporum

    PubMed Central

    Korbekandi, Hassan; Ashari, Zeynab; Iravani, Siavash; Abbasi, Sajjad

    2013-01-01

    Silver nanoparticles are increasingly used in various fields of biotechnology and applications in the medicine. Objectives of this study were optimization of production of silver nanoparticles using biotransformations by Fusarium oxysporum, and a further study on the location of nanoparticles synthesis in this microorganism. The reaction mixture contained the following ingredients (final concentrations): AgNO3 (1-10 mM) as the biotransformation substrate, biomass as the biocatalyst, glucose (560 mM) as the electron donor, and phosphate buffer (pH= 7, 100 mM). The samples were taken from the reaction mixtures at different times, and the absorbance (430 nm) of the colloidal suspensions of silver nanoparticles hydrosols was read freshly (without freezing) and immediately after dilution (1:40). SEM and TEM analyses were performed on selected samples. The presence of AgNO3 (0.1 mM) in the culture as enzyme inducer, and glucose (560 mM) as electron donor had positive effects on nanoparticle production. In SEM micrographs, silver nanoparticles were almost spherical, single (25-50 nm) or in aggregates (100 nm), attached to the surface of biomass. The reaction mixture was successfully optimized to increase the yield of silver nanoparticles production. More details of the location of nanoparticles production by this fungus were revealed, which support the hypothesis that silver nanoparticles are synthesized intracellularly and not extracellularly. PMID:24250635

  2. Incorporation Effect of Silver Nanoparticles on Inverted Type Bulk-Heterojunction Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Matsumoto, Taisuke; Oku, Takeo; Akiyama, Tsuyoshi

    2013-04-01

    A series of bulk-heterojunction organic solar cells incorporating silver nanoparticles was fabricated and evaluated. Silver nanoparticles were incorporated in the hole-transport layer of the solar cells. Plasmonic absorption and the generation of localized surface plasmon resonance of silver nanoparticles were confirmed by absorption and surface enhanced Raman scattering spectra even in the hole-transport material. The incorporation of silver nanoparticles increased photoelectric conversion efficiencies, whose enhancement properties were varied by the incorporation amount of silver nanoparticles.

  3. Size-separation of silver nanoparticles using sucrose gradient centrifugation

    DOE PAGES

    Suresh, Anil K.; Pelletier, Dale A.; Moon, Ji Won; ...

    2015-08-28

    Size and shape distributions of nanoparticles can drastically contribute to the overall properties of nanoparticles, thereby influencing their interaction with different chemotherapeutic molecules, biological organisms and or materials and cell types. Therefore, to exploit the proper use of nanoparticles for various biomedical and biosensor applications, it is important to obtain well-separated monodispersed nanoparticles. However, gaining precise control over the morphological characteristics of nanoparticles during their synthesis is often a challenging task. Consequently, post-synthesis separation of nanoparticles is necessary. In the present study, we demonstrate the successful one-pot post-synthesis separation of anisotropic silver nanoparticles to near modispersities using sucrose density gradientmore » sedimentation. The separation of the nanoparticles was evidenced based on optical confirmation, and spectrophotometric and transmission electron microscopy measurements. Our results clearly demonstrate the facile separation of anisotropic silver nanoparticles using sucrose density gradient sedimentation and can enable the use of nanoparticles for various biomedical applications.« less

  4. Size-separation of silver nanoparticles using sucrose gradient centrifugation

    SciTech Connect

    Suresh, Anil K.; Pelletier, Dale A.; Moon, Ji Won; Phelps, Tommy; Doktycz, Mitchel John

    2015-08-28

    Size and shape distributions of nanoparticles can drastically contribute to the overall properties of nanoparticles, thereby influencing their interaction with different chemotherapeutic molecules, biological organisms and or materials and cell types. Therefore, to exploit the proper use of nanoparticles for various biomedical and biosensor applications, it is important to obtain well-separated monodispersed nanoparticles. However, gaining precise control over the morphological characteristics of nanoparticles during their synthesis is often a challenging task. Consequently, post-synthesis separation of nanoparticles is necessary. In the present study, we demonstrate the successful one-pot post-synthesis separation of anisotropic silver nanoparticles to near modispersities using sucrose density gradient sedimentation. The separation of the nanoparticles was evidenced based on optical confirmation, and spectrophotometric and transmission electron microscopy measurements. Our results clearly demonstrate the facile separation of anisotropic silver nanoparticles using sucrose density gradient sedimentation and can enable the use of nanoparticles for various biomedical applications.

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

    PubMed

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

    2010-05-07

    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.

  6. 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.

  7. Antibacterial and photocatalytic degradation efficacy of silver nanoparticles biosynthesized using Cordia dichotoma leaf extract

    NASA Astrophysics Data System (ADS)

    Mankamna Kumari, R.; Thapa, Nikita; Gupta, Nidhi; Kumar, Ajeet; Nimesh, Surendra

    2016-12-01

    The present study focuses on the biosynthesis of silver nanoparticles (AgNPs) along with its antibacterial and photocatalytic activity. The AgNPs were synthesized using Cordia dichotoma leaf extract and were characterized using UV-vis spectroscopy to determine the formation of AgNPs. FTIR was done to discern biomolecules responsible for reduction and capping of the synthesized nanoparticles. Further, DLS technique was performed to examine its hydrodynamic diameter, followed by SEM, TEM and XRD to determine its size, morphology and crystalline structure. Later, these AgNPs were studied for their potential role in antibacterial activity and photocatalytic degradation of azo dyes such as methylene blue and Congo red.

  8. Ultrafast electronic relaxation processes in semiconductor nanoparticles (silver iodide, silver iodide/silver sulfide, silver bromide/silver sulfide, silver sulfide, cupric sulfide, and copper sulfide) and carotenoids

    NASA Astrophysics Data System (ADS)

    Brelle, Michael Chris

    2000-11-01

    This dissertation examines primarily the ultrafast dynamics of excited state charge carriers in semiconductor nanoparticles. The dissertation also briefly examines the excited state lifetimes of a few carotenoids. Understanding the dynamic properties of charge carriers in semiconductor nanoparticles is crucial for the further development of applications utilizing these systems. The dynamic properties including shallow and deep trapping as well as recombination have been studied in a variety of semiconductor nanoparticle systems. Kinetic modeling was utilized to assist in the assignment of all observed signals and the nature of the decays. The first observation of ultrafast trapping in silver halides was observed in AgI nanoparticles including the identification that interstitial silver ions may act as deep traps. Several interesting phenomena were observed in Ag2S and CuxS nanoparticles including dark shallow trap states and shallow trap state saturation leading to increased transient absorption over transient bleach with increasing excitation intensity. These observations have provided further insight into the relaxation pathways for charge carriers in semiconductor nanoparticle systems. Lifetimes of the S2 excited states of four carotenoids have also been determined. The S2 lifetime for beta-carotene was confirmed from previous fluorescence up-conversion experiments whereas the S2 lifetimes that were previously unknown for three carotenoids, violaxanthin, neaxanthin, and lutein were discovered. These experiments together demonstrate the capabilities of femtosecond pump-probe spectroscopy to characterize and better understand the processes involved in the ultrafast relaxation events in both molecular and nanoparticle systems.

  9. Mechanistic Study of Silver Nanoparticle's Synthesis by Dragon's Blood Resin Ethanol Extract and Antiradiation Activity.

    PubMed

    Hasan, Murtaza; Iqbal, Javed; Awan, Umer; Saeed, Yasmeen; Ranran, Yuan; Liang, Yanli; Dai, Rongji; Deng, Yulin

    2015-02-01

    Biological synthesis of nanoparticles is best way to avoid exposure of hazardous materials as compared to chemical manufacturing process which is a severe threat not only to biodiversity but also to environment. In present study, we reported a novel method of finding antiradiation compounds by bioreducing mechanism of silver nanoparticles formation using 50% ethanol extract of Dragons blood, a famous Chinese herbal plant. Color change during silver nanoparticles synthesis was observed and it was confirmed by ultra violet (UV) visible spectroscopy at wave length at 430 nm after 30 min of reaction at 60 °C. Well dispersed round shaped silver nanoparticles with approximate size (4 nm to 50 nm) were measured by TEM and particle size analyser. Capping of biomolecules on Ag nanoparticles was characterized by FTIR spectra. HPLC analysis was carried out to find active compounds in the extract. Furthermore, antiradiation activity of this extract was tested by MTT assay in vitro after incubating the SH-SY5Y cells for 24 h at 37 °C. The results indicate that presence of active compounds in plant extract not only involves in bioreduction process but also shows response against radiation. The dual role of plant extract as green synthesis of nanoparticles and exhibit activity against radiation which gives a new way of fishing out active compounds from complex herbal plants.

  10. Mangrove Streptomyces sp. BDUKAS10 as nanofactory for fabrication of bactericidal silver nanoparticles.

    PubMed

    Sivalingam, Periyasamy; Antony, Jacob Joe; Siva, Durairaj; Achiraman, Shanmugam; Anbarasu, Kumarasamy

    2012-10-01

    Biosynthesis has led to the development of various biomimetic approaches for the fabrication of nanoscale materials. The present study reveals a unique procedure for the biosynthesis of bactericidal silver nanoparticles (AgNPs) using a novel Streptomyces sp. BDUKAS10, an isolate of mangrove sediment. Aqueous silver nitrate (AgNO(3)) solution was treated with cell free supernatant (CFS) of the isolate to synthesize bactericidal silver nanoparticles. Initial characterization was performed by visual observation for color change to intense brown color. UV-visible spectrophotometry (UV-vis) for measuring surface plasmon resonance indicated a maximum absorption peak at 441 nm. Fourier Transform Infrared Spectroscopy (FTIR) analysis provides evidence for proteins as possible reducing, and capping agents. Energy dispersive X-ray (EDAX) spectroscopy analysis showed elemental silver as major signal. Transmission Electron Microscopy (TEM) study indicated spherical silver nanoparticles in the size range of 21-48 nm. Compared to the CFS, the biosynthesized AgNPs exemplified superior bactericidal efficacy towards the tested bacterial strains. Results from this study suggested that Streptomyces sp. BDUKAS10 can be advantageous for the synthesis of AgNPs by extracellular method in the view of sustainable and ecofriendly approach.

  11. Lectin sensitized anisotropic silver nanoparticles for detection of some bacteria.

    PubMed

    Gasparyan, Vardan K; Bazukyan, Inga L

    2013-03-05

    A method of bacteria detection by sensitized anisotropic silver nanoparticles is presented. Anisotropic silver nanoparticles with two bands of surface plasmon resonance (SPR) are prepared and sensitized with potato lectin. These nanoparticles are able to detect three bacterial species: Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The interaction of these bacteria with such nanoparticles induces drastic changes in optical spectra of nanoparticles that are correlated with bacteria titer. The maximal sensitivity is observed for S. aureus (up to 1.5×10(4) mL(-1)).

  12. The immunomodulatory effects of titanium dioxide and silver nanoparticles.

    PubMed

    Lappas, Courtney M

    2015-11-01

    Due to their characteristic physical, chemical and optical properties, titanium dioxide and silver nanoparticles are attractive tools for use in a wide range of applications. The use of nanoparticles for biological applications is, however, dependent upon their biocompatibility with living cells. Because of the importance of inflammation as a modulator of human health, the safe and efficacious in vivo use of titanium dioxide and silver nanoparticles is inherently linked to a favorable interaction with immune system cells. However, both titanium dioxide and silver nanoparticles have demonstrated potential to exert immunomodulatory and immunotoxic effects. Titanium dioxide and silver nanoparticles are readily internalized by immune system cells, may accumulate in peripheral lymphoid organs, and can influence multiple manifestations of immune cell activity. Although the factors influencing the biocompatibility of titanium dioxide and silver nanoparticles with immune system cells have not been fully elucidated, nanoparticle core composition, size, concentration and the duration of cell exposure seem to be important. Because titanium dioxide and silver nanoparticles are widely utilized in pharmaceutical, commercial and industrial products, it is vital that their effects on human health and immune system function be more thoroughly evaluated.

  13. Green synthesis of silver nanoparticles using Andean blackberry fruit extract.

    PubMed

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

    2017-01-01

    Green synthesis of nanoparticles using various plant materials opens a new scope for the phytochemist and discourages the use of toxic chemicals. In this article, we report an eco-friendly and low-cost method for the synthesis of silver nanoparticles (AgNPs) using Andean blackberry fruit extracts as both a reducing and capping agent. The green synthesized AgNPs were characterized by various analytical instruments like UV-visible, transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The formation of AgNPs was analyzed by UV-vis spectroscopy at λmax = 435 nm. TEM analysis of AgNPs showed the formation of a crystalline, spherical shape and 12-50 nm size, whereas XRD peaks at 38.04°, 44.06°, 64.34° and 77.17° confirmed the crystalline nature of AgNPs. FTIR analysis was done to identify the functional groups responsible for the synthesis of the AgNPs. Furthermore, it was found that the AgNPs showed good antioxidant efficacy (>78%, 0.1 mM) against 1,1-diphenyl-2-picrylhydrazyl. The process of synthesis is environmentally compatible and the synthesized AgNPs could be a promising candidate for many biomedical applications.

  14. Size-dependent toxicity of silver nanoparticles to Glyptotendipes tokunagai

    PubMed Central

    Choi, Seona; Kim, Soyoun; Bae, Yeon-Jae; Park, June-Woo; Jung, Jinho

    2015-01-01

    Objectives This study aims to evaluate the size-dependent toxicity of spherical silver nanoparticles (Ag NPs) to an endemic benthic organism, Glyptotendipes tokunagai. Methods Ag nanoparticles of three nominal sizes (50, 100, and 150 nm) capped with polyvinyl pyrrolidone (PVP-Ag NPs) were used. Their physicochemical properties, acute toxicity (48 hours), and bioaccumulation were measured using third instar larvae of G. tokunagai. Results The aggregation and dissolution of PVP-Ag NPs increased with exposure time and concentration, respectively, particularly for 50 nm PVP-Ag NPs. However, the dissolved concentration of Ag ions was not significant compared with the median lethal concentration value for AgNO3 (3.51 mg/L). The acute toxicity of PVP-Ag NPs was highest for the smallest particles (50 nm), whereas bioaccumulation was greatest for the largest particles (150 nm). However, larger PVP-Ag NPs were absorbed and excreted rapidly, resulting in shorter stays in G. tokunagai than the smaller ones. Conclusions The size of PVP-Ag NPs significantly affects their acute toxicity to G. tokunagai. In particular, smaller PVP-Ag NPs have a higher solubility and stay longer in the body of G. tokunagai, resulting in higher toxicity than larger PVP-Ag NPs. PMID:26184045

  15. Thermostability and reversibility of silver nanoparticle-protein binding.

    PubMed

    Wang, Bo; Seabrook, Shane A; Nedumpully-Govindan, Praveen; Chen, Pengyu; Yin, Hong; Waddington, Lynne; Epa, V Chandana; Winkler, David A; Kirby, Jason K; Ding, Feng; Ke, Pu Chun

    2015-01-21

    The interactions between nanoparticles (NPs) and proteins in living systems are a precursor to the formation of a NP-protein "corona" that underlies cellular and organism responses to nanomaterials. However, the thermodynamic properties and reversibility of NP-protein interactions have rarely been examined. Using an automated, high-throughput and temperature-controlled dynamic light scattering (DLS) technique we observed a distinct hysteresis in the hydrodynamic radius of branched polyethyleneimine (BPEI) coated-silver nanoparticles (bAgNPs) exposed to like-charged lysozyme during the processes of heating and cooling, in contrast to the irreversible interactions between bAgNPs and oppositely charged alpha lactalbumin (ALact). Our discrete molecular dynamics (DMD) simulations offered a new molecular insight into the differential structure, dynamics and thermodynamics of bAgNPs binding with the two protein homologs and further revealed the different roles of the capping agents of citrate and BPEI in NP-protein interactions. This study facilitates our understanding of the transformation of nanomaterials in living systems, whose implications range from the field study of nanotoxicology to nanomaterials synthesis, nanobiotechnology and nanomedicine.

  16. Influence of oxygen on the optical properties of silver nanoparticles.

    PubMed

    Renteria-Tapia, V M; García-Macedo, J

    2008-12-01

    Silver nanoparticles in sol-gel silica films were obtained by annealing in hydrogen atmosphere and subsequently in oxygen atmosphere. Their properties were measured by UV-vis spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electronic microscopy (HRTEM) and X-ray diffraction analysis. Samples prepared in a reducing atmosphere exhibited a surface plasmon resonance (SPR) located at 399 nm. Silver nanoparticles in an oxidizing atmosphere exhibited a red shift and damping of the SPR. These optical properties were explained due to the oxidation on the surface of silver nanoparticles to silver oxide yield in an oxygen atmosphere. Silver core-silver oxide shell nanostructures were observed by HRTEM. The average size of the metallic nanoparticles obtained by TEM was used for modeling the UV-vis spectra by using the Gans theory. Good fits to the spectra under an oxidizing atmosphere were obtained considering variable refractive indexes coming from the silver oxide shells surrounding to the nanoparticles. Therefore, the interaction between oxygen and the metallic surface of the nanoparticles, sensitively alters their optical properties.

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

    NASA Astrophysics Data System (ADS)

    Vilas, Vidya; Philip, Daizy; Mathew, Joseph

    2014-11-01

    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.

  18. Fluctuation Spectroscopy Analysis of Glucose Capped Gold Nanoparticles.

    PubMed

    Porcaro, F; Miao, Y; Kota, R; Haun, J B; Polzonetti, G; Battocchio, C; Gratton, E

    2016-12-20

    In this work, we report the synthesis and biophysical studies carried out on a new kind of biocompatible and very stable gold nanoparticle (GNP) stabilized with glucose through a PEG linker (AuNP-PEG-Glu). The synthetic path was optimized to obtain nanoparticles of controlled sizes. ζ-potential and dynamic light scattering measurements allowed assessment of the nanodimension, dispersity, surface charge, and stability of our GNPs. Confocal microscopy demonstrated qualitatively that glucose molecules are successfully bonded to GNP surfaces. For our study, we selected nanoparticles with diameter in a range that maximizes the internalization efficiency in cells (40 nm). A detailed investigation about the biophysical proprieties of AuNP-PEG-Glu was carried out by means of fluorescence correlation spectroscopy (FCS) and orbital tracking techniques. This work gives new insights about the uptake mechanism of gold nanoparticles capped with glucose molecules.

  19. Non-hazardous anticancerous and antibacterial colloidal 'green' silver nanoparticles.

    PubMed

    Barua, Shaswat; Konwarh, Rocktotpal; Bhattacharya, Satya Sundar; Das, Pallabi; Devi, K Sanjana P; Maiti, Tapas K; Mandal, Manabendra; Karak, Niranjan

    2013-05-01

    Poly(ethylene glycol) stabilized colloidal silver nanoparticles were prepared using the reductive potency of the aqueous extract of Thuja occidentalis leaves under ambient conditions. The nanoparticles were well dispersed within a narrow size spectrum (7-14 nm) and displayed characteristic surface plasmon resonance peak at around 420 nm and Bragg's reflection planes of fcc structure. MTT assay revealed the dose-dependent cytocompatibility and toxicity of the nanoparticles with the L929 normal cell line. On the other hand, the antiproliferative action of the nanoparticles was evaluated on HeLa cell (cancerous cells) line. Fluorescence and phase contrast microscopic imaging indicated the appearance of multinucleate stages with aggregation and nuclear membrane disruption of the HeLa cells post treatment with the nanoparticles. The interaction at the prokaryotic level was also assessed via differential antibacterial efficacy against Staphylococcus aureus (MTCC 3160) and Escherichia coli (MTCC 40). Under these perspectives, it is also necessary to observe the environmental impact of the prepared silver nanoparticles. Hence, the dose dependent toxicity of silver nanoparticles was evaluated upon the earthworm species Eisenia fetida. Neither the survival nor the reproduction was affected by the addition of silver nanoparticles up to 1000 ppm. Thus these 'green' silver nanoparticles have promising potential as future materials.

  20. The development of a green approach for the biosynthesis of silver and gold nanoparticles by using Panax ginseng root extract, and their biological applications.

    PubMed

    Singh, Priyanka; Kim, Yeon Ju; Wang, Chao; Mathiyalagan, Ramya; Yang, Deok Chun

    2016-06-01

    The biosynthesis of nanoparticles has received attention because of the development of economic and environmentally friendly technology for the synthesis of nanoparticles. The study develops a convenient method for the green synthesis of silver and gold nanoparticles by utilizing fresh root extract of the four-year old Panax ginseng plant, and evaluated the antimicrobial applications of silver nanoparticles against pathogenic microorganisms. P. ginseng is a well-known herbal medicinal plant, and its active ingredients are mainly ginsenosides. The fresh root of the 4 year old P. ginseng plant has been explored for the synthesis of silver and gold nanoparticles without the use of any additional reducing and capping agents. The reduction of silver nitrate led to the formation of silver nanoparticles within 2 h of reaction at 80°C. The gold nanoparticles were also successfully synthesized by the reduction of auric acid at 80°C, within 5 min of reaction. The biosynthesized gold and silver nanoparticles were characterized by techniques using various instruments, viz. ultraviolet-visible spectroscopy (UV-Vis spectroscopy), field emission transmission electron microscopy (FE-TEM), energy dispersive X-ray analysis (EDX), elemental mapping, and X-ray diffraction (XRD). In addition, the silver nanoparticles have shown antimicrobial potential against Bacillus anthracis, Vibrio parahaemolyticus, Staphylococcus aureus, Escherichia coli, and Bacillus cereus.

  1. Antibacterial Activity of Polyaniline Coated Silver Nanoparticles Synthesized from Piper Betle Leaves Extract.

    PubMed

    Mamun Or Rashida, Md; Shafiul Islam, Md; Azizul Haque, Md; Arifur Rahman, Md; Tanvir Hossain, Md; Abdul Hamid, Md

    2016-01-01

    Plants or natural resources have been found to be a good alternative method for nanoparticles synthesis. In this study, polyaniline coated silver nanoparticles (AgNPs) synthesized from Piper betle leaves extract were investigated for their antibacterial activity. Silver nanoparticles were prepared from the reduction of silver nitrate and NaBH4 was used as reducing agent. Silver nanoparticles and extracts were mixed thoroughly and then coated by polyaniline. Prepared nanoparticles were characterized by Visual inspection, Ultraviolet-visible spectroscopy (UV), Fourier transform infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM) techniques. Antibacterial activities of the synthesized silver nanoparticles were tested against Staphylococcus aureus ATCC 25923, Salmonella typhi ATCC 14028, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. UV-Vis spectrum of reaction mixture showed strong absorption peak with centering at 400 nm. The FT-IR results imply that Ag-NPs were successfully synthesized and capped with bio-compounds present in P. betle. TEM image showed that Ag-NPs formed were well dispersed with a spherical structures and particle size ranging from 10 to 30 nm. The result revealed that Ag-Extract NPs showed 32.78±0.64 mm zone of inhibition against S. aureus, whereas norfloxacin (positive control) showed maximum 32.15±0.40 mm zone of inhibition for S. aureus. Again, maximum zone of inhibition 29.55±0.45 mm was found for S. typhi, 27.12±0.38 mm for E. coli and 21.95±0.45 mm for P. aeruginosa. The results obtained by this study can't be directly extrapolated to human; so further studies should be undertaken to established the strong antimicrobial activity of Ag-Extract NPs for drug development program.

  2. Antibacterial Activity of Polyaniline Coated Silver Nanoparticles Synthesized from Piper Betle Leaves Extract

    PubMed Central

    Mamun Or Rashida, Md.; Shafiul Islam, Md.; Azizul Haque, Md.; Arifur Rahman, Md.; Tanvir Hossain, Md.; Abdul Hamid, Md.

    2016-01-01

    Plants or natural resources have been found to be a good alternative method for nanoparticles synthesis. In this study, polyaniline coated silver nanoparticles (AgNPs) synthesized from Piper betle leaves extract were investigated for their antibacterial activity. Silver nanoparticles were prepared from the reduction of silver nitrate and NaBH4 was used as reducing agent. Silver nanoparticles and extracts were mixed thoroughly and then coated by polyaniline. Prepared nanoparticles were characterized by Visual inspection, Ultraviolet-visible spectroscopy (UV), Fourier transform infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM) techniques. Antibacterial activities of the synthesized silver nanoparticles were tested against Staphylococcus aureus ATCC 25923, Salmonella typhi ATCC 14028, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. UV–Vis spectrum of reaction mixture showed strong absorption peak with centering at 400 nm. The FT-IR results imply that Ag-NPs were successfully synthesized and capped with bio-compounds present in P. betle. TEM image showed that Ag-NPs formed were well dispersed with a spherical structures and particle size ranging from 10 to 30 nm. The result revealed that Ag-Extract NPs showed 32.78±0.64 mm zone of inhibition against S. aureus, whereas norfloxacin (positive control) showed maximum 32.15±0.40 mm zone of inhibition for S. aureus. Again, maximum zone of inhibition 29.55±0.45 mm was found for S. typhi, 27.12±0.38 mm for E. coli and 21.95±0.45 mm for P. aeruginosa. The results obtained by this study can’t be directly extrapolated to human; so further studies should be undertaken to established the strong antimicrobial activity of Ag-Extract NPs for drug development program. PMID:27642330

  3. Eco-friendly synthesis of gelatin-capped bimetallic Au-Ag nanoparticles for chemiluminescence detection of anticancer raloxifene hydrochloride.

    PubMed

    Alarfaj, Nawal A; El-Tohamy, Maha F

    2016-09-01

    This study described the utility of green analytical chemistry in the synthesis of gelatin-capped silver, gold and bimetallic gold-silver nanoparticles (NPs). The preparation of nanoparticles was based on the reaction of silver nitrate or chlorauric acid with a 1.0 wt% aqueous gelatin solution at 50°C. The gelatin-capped silver, gold and bimetallic NPs were characterized using transmission electron microscopy, UV-vis, X-ray diffraction and Fourier transform infrared spectroscopy, and were used to enhance a sensitive sequential injection chemiluminescence luminol-potassium ferricyanide system for determination of the anticancer drug raloxifene hydrochloride. The developed method is eco-friendly and sensitive for chemiluminescence detection of the selected drug in its bulk powder, pharmaceutical injections and biosamples. After optimizing the conditions, a linear relationship in the range of 1.0 × 10(-9) to 1.0 × 10(-1)  mol/L was obtained with a limit of detection of 5.0 × 10(-10)  mol/L and a limit of quantification of 1.0 × 10(-9)  mol/L. Statistical treatment and method validation were performed based on ICH guidelines. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Nanoindentation of Chitosan Doped with Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Palumbo, Matthew; Teklu, Alem; Kuthirummal, Narayanan; Levi-Polyachenko, Nicole; Department of Physics; Astronomy, College of Charleston Collaboration; Department of Plastic; Reconstructive Surgery, Wake Forest University Health Sciences Collaboration

    Imaging and spectroscopic analysis via nanoindentation was performed with the Nanosurf EasyScan2 AFM on the pure and silver doped chitosan samples allowing for a more localized determination of their stiffness, hardness, and reduced Young's modulus. The pure chitosan sample was tested to have a stiffness of 0.367 N/m, a hardness of 1.12 GPa, and a reduced Young's modulus of 30.5 MPa. The film with 5mg Ag nanoparticle per gram of chitosan was tested on the boundaries between the chitosan and Ag nanoparticles to show an increase in stiffness of about 4.6% at 0.384 N/m, an increase in hardness of about 5.4% at 1.18 GPa, and an increase in the reduced Young's modulus of about 5.0% at 3.2 MPa in comparison to the pure chitosan sample. On the other hand, upon increasing the doping to 10mg Ag nanoparticle per gram of chitosan showed a decrease in stiffness of about 6.3% at 0.344 N/m, a decrease in hardness of about 27.0% at 0.820 GPa, and a decrease in the reduced Young's modulus of about 6.0% at 28.7 MPa in comparison to the pure chitosan sample. Obviously, films doped with 5mg Ag nanoparicle per gram of chitosan provided the composites with improved mechanical strength compared to chitosan alone.

  5. Biogenic synthesis of gold and silver nanoparticles by seed plants.

    PubMed

    Iyer, R Indira; Panda, Tapobrata

    2014-02-01

    Nanoparticles have an enormous range of biomedical and environmental applications and can be used for development of various nanodevices for diagnostics and drug delivery. Biogenic production of nanoparticles, that is of silver and gold, by seed plants, especially flowering plants, has evoked considerable interest in the last decade. Different organs of plants as well as callus cultures have been used for the production of these metal nanoparticles. It is possible to regulate the geometry of the nanoparticles by modifying the experimental parameters. In many cases the phytosynthesized gold and silver nanoparticles have been demonstrated to be potentially useful for treatment of various diseases. The production of gold and silver nanoparticles by diverse species of seed plants and their biological activity are discussed in this article.

  6. Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species.

    PubMed

    Zomorodian, Kamiar; Pourshahid, Seyedmohammad; Sadatsharifi, Arman; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

    2016-01-01

    Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM). There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity.

  7. 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.

  8. Biosynthesis and Characterization of Silver Nanoparticles by Aspergillus Species

    PubMed Central

    Pourshahid, Seyedmohammad; Mehryar, Pouyan; Pakshir, Keyvan; Rahimi, Mohammad Javad; Arabi Monfared, Ali

    2016-01-01

    Currently, researchers turn to natural processes such as using biological microorganisms in order to develop reliable and ecofriendly methods for the synthesis of metallic nanoparticles. In this study, we have investigated extracellular biosynthesis of silver nanoparticles using four Aspergillus species including A. fumigatus, A. clavatus, A. niger, and A. flavus. We have also analyzed nitrate reductase activity in the studied species in order to determine the probable role of this enzyme in the biosynthesis of silver nanoparticles. The formation of silver nanoparticles in the cell filtrates was confirmed by the passage of laser light, change in the color of cell filtrates, absorption peak at 430 nm in UV-Vis spectra, and atomic force microscopy (AFM). There was a logical relationship between the efficiencies of studied Aspergillus species in the production of silver nanoparticles and their nitrate reductase activity. A. fumigatus as the most efficient species showed the highest nitrate reductase activity among the studied species while A. flavus exhibited the lowest capacity in the biosynthesis of silver nanoparticles which was in accord with its low nitrate reductase activity. The present study showed that Aspergillus species had potential for the biosynthesis of silver nanoparticles depending on their nitrate reductase activity. PMID:27652264

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

    PubMed

    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.

  11. The effects of bacteria-nanoparticles interface on the antibacterial activity of green synthesized silver nanoparticles.

    PubMed

    Ahmad, Aftab; Wei, Yun; Syed, Fatima; Tahir, Kamran; Rehman, Aziz Ur; Khan, Arifullah; Ullah, Sadeeq; Yuan, Qipeng

    2017-01-01

    Neutralization of bacterial cell surface potential using nanoscale materials is an effective strategy to alter membrane permeability, cytoplasmic leakage, and ultimate cell death. In the present study, an attempt was made to prepare biogenic silver nanoparticles using biomolecules from the aqueous rhizome extract of Coptis Chinensis. The biosynthesized silver nanoparticles were surface modified with chitosan biopolymer. The prepared silver nanoparticles and chitosan modified silver nanoparticles were cubic crystalline structures (XRD) with an average particle size of 15 and 20 nm respectively (TEM, DLS). The biosynthesized silver nanoparticles were surface stabilized by polyphenolic compounds (FTIR). Coptis Chinensis mediated silver nanoparticles displayed significant activity against E. coli and Bacillus subtilus with a zone of inhibition 12 ± 1.2 (MIC = 25 μg/mL) and 18 ± 1.6 mm (MIC = 12.50 μg/mL) respectively. The bactericidal efficacy of these nanoparticles was considerably increased upon surface modification with chitosan biopolymer. The chitosan modified biogenic silver nanoparticles exhibited promising activity against E. coli (MIC = 6.25 μg/mL) and Bacillus subtilus (MIC = 12.50 μg/mL). Our results indicated that the chitosan modified silver nanoparticles were promising agents in damaging bacterial membrane potential and induction of high level of intracellular reactive oxygen species (ROS). In addition, these nanoparticles were observed to induce the release of the high level of cytoplasmic materials especially protein and nucleic acids into the media. All these findings suggest that the chitosan functionalized silver nanoparticles are efficient agents in disrupting bacterial membrane and induction of ROS leading to cytoplasmic leakage and cell death. These findings further conclude that the bacterial-nanoparticles surface potential modulation is an effective strategy in enhancing the antibacterial potency of silver nanoparticles.

  12. 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.

  13. 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...

  14. Colorimetric determination of melamine in milk using unmodified silver nanoparticles.

    PubMed

    Kumar, Naveen; Kumar, Harish; Mann, Bimlesh; Seth, Raman

    2016-03-05

    Melamine is nitrogen rich chemical compound used as an adulterant in dairy products by unscrupulous people to increase the apparent protein content. This incident prompted the researchers to develop simple methods for easy detection of melamine in food samples. In the present paper, we report a simple and sensitive colorimetric method for detection of melamine in milk based on silver nanoparticles. This method relies upon the principle that melamine causes the aggregation of silver nanoparticles, resulting in abrupt color change from yellow to red under optimized conditions. The concentration of melamine in adulterated sample can be quantitated by monitoring the absorption spectra of silver nanoparticles using ultraviolet-visible (UV-Vis) spectrometer. The present colorimetric method which utilizes silver nanoparticles of 35 nm can reliably detect melamine down to a concentration of 0.04 mg l(-1).

  15. Colorimetric determination of melamine in milk using unmodified silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, Naveen; Kumar, Harish; Mann, Bimlesh; Seth, Raman

    2016-03-01

    Melamine is nitrogen rich chemical compound used as an adulterant in dairy products by unscrupulous people to increase the apparent protein content. This incident prompted the researchers to develop simple methods for easy detection of melamine in food samples. In the present paper, we report a simple and sensitive colorimetric method for detection of melamine in milk based on silver nanoparticles. This method relies upon the principle that melamine causes the aggregation of silver nanoparticles, resulting in abrupt color change from yellow to red under optimized conditions. The concentration of melamine in adulterated sample can be quantitated by monitoring the absorption spectra of silver nanoparticles using ultraviolet-visible (UV-Vis) spectrometer. The present colorimetric method which utilizes silver nanoparticles of 35 nm can reliably detect melamine down to a concentration of 0.04 mg l- 1.

  16. Antibacterial nanocarriers of resveratrol with gold and silver nanoparticles.

    PubMed

    Park, Sohyun; Cha, Song-Hyun; Cho, Inyoung; Park, Soomin; Park, Yohan; Cho, Seonho; Park, Youmie

    2016-01-01

    This study focused on the preparation of resveratrol nanocarrier systems and the evaluation of their in vitro antibacterial activities. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) for resveratrol nanocarrier systems were synthesized using green synthetic routes. During the synthesis steps, resveratrol was utilized as a reducing agent to chemically reduce gold and silver ions to AuNPs and AgNPs. This system provides green and eco-friendly synthesis routes that do not involve additional chemical reducing agents. Resveratrol nanocarriers with AuNPs (Res-AuNPs) and AgNPs (Res-AgNPs) were observed to be spherical and to exhibit characteristic surface plasmon resonance at 547 nm and at 412-417 nm, respectively. The mean size of the nanoparticles ranged from 8.32 to 21.84 nm, as determined by high-resolution transmission electron microscopy. The face-centered cubic structure of the Res-AuNPs was confirmed by high-resolution X-ray diffraction. Fourier-transform infrared spectra indicated that the hydroxyl groups and C=C in the aromatic ring of resveratrol were involved in the reduction reaction. Res-AuNPs retained excellent colloidal stability during ultracentrifugation and re-dispersion, suggesting that resveratrol also played a role as a capping agent. Zeta potentials of Res-AuNPs and Res-AgNPs were in the range of -20.58 to -48.54 mV. Generally, against Gram-positive and Gram-negative bacteria, the Res-AuNPs and Res-AgNPs exhibited greater antibacterial activity compared to that of resveratrol alone. Among the tested strains, the highest antibacterial activity of the Res-AuNPs was observed against Streptococcus pneumoniae. The addition of sodium dodecyl sulfate during the synthesis of Res-AgNPs slightly increased their antibacterial activity. These results suggest that the newly developed resveratrol nanocarrier systems with metallic nanoparticles show potential for application as nano-antibacterial agents with enhanced activities.

  17. 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 ...

  18. Modelling encapsulation of gold and silver nanoparticles inside lipid nanotubes

    NASA Astrophysics Data System (ADS)

    Baowan, Duangkamon; Thamwattana, Ngamta

    2014-02-01

    Lipid nanotubes are of particular interest for use as a template to create various one-dimensional nanostructures and as a carrier for drug and gene delivery. Understanding the encapsulation process is therefore crucial for such development. This paper models the interactions between lipid nanotubes and spheres of gold and silver nanoparticles and determines the critical dimension of lipid nanotubes that maximises the interaction with the nanoparticles. Our results confirm the acceptance of gold and silver nanoparticles inside lipid nanotubes. Further, we find that the lipid nanotube of radius approximately 10.23 nm is most favourable to encapsulate both types of nanoparticles.

  19. Imaging of Biological Cells Using Luminescent Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Kravets, Vira; Almemar, Zamavang; Jiang, Ke; Culhane, Kyle; Machado, Rosa; Hagen, Guy; Kotko, Andriy; Dmytruk, Igor; Spendier, Kathrin; Pinchuk, Anatoliy

    2016-01-01

    The application of luminescent silver nanoparticles as imaging agents for neural stem and rat basophilic leukemia cells was demonstrated. The experimental size dependence of the extinction and emission spectra for silver nanoparticles were also studied. The nanoparticles were functionalized with fluorescent glycine dimers. Spectral position of the resonance extinction and photoluminescence emission for particles with average diameters ranging from 9 to 32 nm were examined. As the particle size increased, the spectral peaks for both extinction and the intrinsic emission of silver nanoparticles shifted to the red end of the spectrum. The intrinsic photoluminescence of the particles was orders of magnitude weaker and was spectrally separated from the photoluminescence of the glycine dimer ligands. The spectral position of the ligand emission was independent of the particle size; however, the quantum yield of the nanoparticle-ligand system was size-dependent. This was attributed to the enhancement of the ligand's emission caused by the local electric field strength's dependence on the particle size. The maximum quantum yield determined for the nanoparticle-ligand complex was (5.2 ± 0.1) %. The nanoparticles were able to penetrate cell membranes of rat basophilic leukemia and neural stem cells fixed with paraformaldehyde. Additionally, toxicity studies were performed. It was found that towards rat basophilic leukemia cells, luminescent silver nanoparticles had a toxic effect in the silver atom concentration range of 10-100 μM.

  20. Photosensitized synthesis of silver nanoparticles using Withania somnifera leaf powder and silver nitrate.

    PubMed

    Raut, Rajesh Warluji; Mendhulkar, Vijay Damodhar; Kashid, Sahebrao Balaso

    2014-03-05

    The metal nanoparticle synthesis is highly explored field of nanotechnology. The biological methods seem to be more effective; however, due to slow reduction rate and polydispersity of the resulting products, they are less preferred. In the present study, we report rapid and facile synthesis of silver nanoparticles at room temperature. The exposure of reaction mixtures containing silver nitrate and dried leaf powder of Withania somnifera Linn to direct sunlight resulted in reduction of metal ions within five minutes whereas, the dark exposure took almost 12h. Further studies using different light filters reveal the role of blue light in reduction of silver ions. The synthesized silver nanoparticles were characterized by UV-Vis, Infrared spectroscopy (IR), Transmission Electron Microscopy (TEM), X-ray Diffraction studies (XRD), Nanoparticle Tracking Analysis (NTA), Energy Dispersive Spectroscopy (EDS), and Cyclic Voltammetry (CV). The Antibacterial and antifungal studies showed significant activity as compared to their respective standards.

  1. Precise micropatterning of silver nanoparticles on plastic substrates

    NASA Astrophysics Data System (ADS)

    Ammosova, Lena; Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A.

    2017-04-01

    Conventional fabrication methods to obtain metal patterns on polymer substrates are restricted by high operating temperature and complex preparation steps. The present study demonstrates a simple yet versatile method for preparation of silver nanoparticle micropatterns on polymer substrates with various surface geometry. With the microworking robot technique, we were able not only to directly structure the surface, but also precisely deposit silver nanoparticle ink on the desired surface location with the minimum usage of ink material. The prepared silver nanoparticle ink, containing silver cations and polyethylene glycol (PEG) as a reducing agent, yields silver nanoparticle micropatterns on plastic substrates at low sintering temperature without any contamination. The influence of the ink behaviour was studied, such as substrate wettability, ink volume, and sintering temperature. The ultraviolet visible (UV-vis), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) measurements revealed the formation of micropatterns with uniformly distributed silver nanoparticles. The prepared patterns are expected to have a broad range of applications in optics, medicine, and sensor devices owing to the unique properties of silver. Furthermore, the deposition of a chemical compound, which is different from the substrate material, not only adds a fourth dimension to the prestructured three-dimensional (3D) surfaces, but also opens new application areas to the conventional surface structures.

  2. Antimicrobial activity and physical characterization of silver nanoparticles green synthesized using nitrate reductase from Fusarium oxysporum.

    PubMed

    Gholami-Shabani, Mohammadhassan; Akbarzadeh, Azim; Norouzian, Dariush; Amini, Abdolhossein; Gholami-Shabani, Zeynab; Imani, Afshin; Chiani, Mohsen; Riazi, Gholamhossein; Shams-Ghahfarokhi, Masoomeh; Razzaghi-Abyaneh, Mehdi

    2014-04-01

    Nanostructures from natural sources have received major attention due to wide array of biological activities and less toxicity for humans, animals, and the environment. In the present study, silver nanoparticles were successfully synthesized using a fungal nitrate reductase, and their biological activity was assessed against human pathogenic fungi and bacteria. The enzyme was isolated from Fusarium oxysporum IRAN 31C after culturing on malt extract-glucose-yeast extract-peptone (MGYP) medium. The enzyme was purified by a combination of ultrafiltration and ion exchange chromatography on DEAE Sephadex and its molecular weight was estimated by gel filtration on Sephacryl S-300. The purified enzyme had a maximum yield of 50.84 % with a final purification of 70 folds. With a molecular weight of 214 KDa, it is composed of three subunits of 125, 60, and 25 KDa. The purified enzyme was successfully used for synthesis of silver nanoparticles in a way dependent upon NADPH using gelatin as a capping agent. The synthesized silver nanoparticles were characterized by X-ray diffraction, dynamic light scattering spectroscopy, and transmission and scanning electron microscopy. These stable nonaggregating nanoparticles were spherical in shape with an average size of 50 nm and a zeta potential of -34.3. Evaluation of the antimicrobial effects of synthesized nanoparticles by disk diffusion method showed strong growth inhibitory activity against all tested human pathogenic fungi and bacteria as evident from inhibition zones that ranged from 14 to 25 mm. Successful green synthesis of biologically active silver nanoparticles by a nitrate reductase from F. oxysporum in the present work not only reduces laborious downstream steps such as purification of nanoparticle from interfering cellular components, but also provides a constant source of safe biologically-active nanomaterials with potential application in agriculture and medicine.

  3. Characterization of silver nanoparticles by green synthesis method using Pedalium murex leaf extract and their antibacterial activity

    NASA Astrophysics Data System (ADS)

    Anandalakshmi, K.; Venugobal, J.; Ramasamy, V.

    2016-03-01

    In this paper, an aqueous extract of fresh leaves of Pedalium murex was used for the synthesis of silver (Ag) nanoparticles. Different biological methods are gaining recognition for the production of silver nanoparticles (AgNPs) due to their multiple applications. The use of plants in the green synthesis of nanoparticles emerges as a cost-effective and eco-friendly approach. Characterization of nanoparticles was done using different methods, which include; ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared (FTIR), powder X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray analysis (EDAX), fluorescence emission spectroscopy, transmission electron microscope (TEM), dynamic light scattering (DLS), zeta potential and antibacterial activity. UV-visible spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at around 430 nm. Fourier transform infrared spectra had shown that the biomolecule compounds were responsible for the reduction and capping material of silver nanoparticles. XRD study showed the particles to be crystalline in nature, with a face-centered cubic (fcc) structure. The size and stability were detected using DLS and zeta potential analysis. The antibacterial activity of AgNPs against generally found bacteria was assessed to find their potential use in silver-containing antibacterial product.

  4. 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.

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

    PubMed

    Song, Jae Yong; Kim, Beom Soo

    2009-01-01

    Five plant leaf extracts (Pine, Persimmon, Ginkgo, Magnolia and Platanus) were used and compared for their extracellular synthesis of metallic silver nanoparticles. Stable silver nanoparticles were formed by treating aqueous solution of AgNO(3) with the plant leaf extracts as reducing agent of Ag(+) to Ag(0). UV-visible spectroscopy was used to monitor the quantitative formation of silver nanoparticles. Magnolia leaf broth was the best reducing agent in terms of synthesis rate and conversion to silver nanoparticles. Only 11 min was required for more than 90% conversion at the reaction temperature of 95 degrees C using Magnolia leaf broth. The synthesized silver nanoparticles were characterized with inductively coupled plasma spectrometry (ICP), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and particle analyzer. The average particle size ranged from 15 to 500 nm. The particle size could be controlled by changing the reaction temperature, leaf broth concentration and AgNO(3) concentration. This environmentally friendly method of biological silver nanoparticles production provides rates of synthesis faster or comparable to those of chemical methods and can potentially be used in various human contacting areas such as cosmetics, foods and medical applications.

  6. Silver ion mediated shape control of platinum nanoparticles: Removal of silver by selective etching leads to increased catalytic activity

    SciTech Connect

    Grass, Michael E.; Yue, Yao; Habas, Susan E.; Rioux, Robert M.; Teall, Chelsea I.; Somorjai, G.A.

    2008-01-09

    A procedure has been developed for the selective etching of Ag from Pt nanoparticles of well-defined shape, resulting in the formation of elementally-pure Pt cubes, cuboctahedra, or octahedra, with a largest vertex-to-vertex distance of {approx}9.5 nm from Ag-modified Pt nanoparticles. A nitric acid etching process was applied Pt nanoparticles supported on mesoporous silica, as well as nanoparticles dispersed in aqueous solution. The characterization of the silica-supported particles by XRD, TEM, and N{sub 2} adsorption measurements demonstrated that the structure of the nanoparticles and the mesoporous support remained conserved during etching in concentrated nitric acid. Both elemental analysis and ethylene hydrogenation indicated etching of Ag is only effective when [HNO{sub 3}] {ge} 7 M; below this concentration, the removal of Ag is only {approx}10%. Ethylene hydrogenation activity increased by four orders of magnitude after the etching of Pt octahedra that contained the highest fraction of silver. High-resolution transmission electron microscopy of the unsupported particles after etching demonstrated that etching does not alter the surface structure of the Pt nanoparticles. High [HNO{sub 3}] led to the decomposition of the capping agent, polyvinylpyrollidone (PVP); infrared spectroscopy confirmed that many decomposition products were present on the surface during etching, including carbon monoxide.

  7. Development of Biogenic Silver Nanoparticle Using Rosa Chinensis Flower Extract and Its Antibacterial Property.

    PubMed

    Meng, Yongde; Sun, Yanjie

    2016-04-01

    In the present study, biosynthesis of silver nanoparticles was carried out using Rosa chinensis flower extract as reducing agent. The characterization of silver nanoparticles was done by UV-VIS spectrum. The morphology and size of silver nanoparticles were determined by transmission electron microscope (TEM) image. The crystallization of silver nanoparticles was confirmed by X-ray diffraction (XRD) measurements. The Fourier transform infrared (FT-IR) analysis was used to confirm the possible involvement in the formation and stabilization of synthesized silver nanoparticles by the extract of Rosa chinensis flower. Antibacterial activity of silver nanoparticles was studied against Gram positive Staphycoccus aureus and Gram negative Escherichia coil.

  8. Biosynthesis, characterization and antibacterial studies of silver nanoparticles using pods extract of Acacia auriculiformis

    NASA Astrophysics Data System (ADS)

    Nalawade, Pradnya; Mukherjee, Poulomi; Kapoor, Sudhir

    2014-08-01

    The present study reports an environmental friendly method for the synthesis of silver nanoparticles (Ag NPs) using an aqueous extract of Acacia auriculiformis that acts as reducing agent as well as capping agent. The obtained NPs were characterized by UV-vis absorption spectroscopy and showed a sharp surface plasmon absorption band at ∼400 nm. Fourier transform infrared spectroscopy (FTIR) showed nanoparticles were capped with plant compounds. Transmission electron microscopy (TEM) showed that the particles were spherical in nature with diameter ranging from 20 to 150 nm depending on the pH of the solution. The as-synthesized Ag NPs showed antibacterial activity against both Gram negative and Gram positive bacteria with more efficacy against Gram negative bacteria.

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

    SciTech Connect

    Mlambo, M.; Moloto, M.J.; Moloto, N.; Mdluli, P.S.

    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.

  10. Synthesis and antibacterial activity of silver nanoparticles with different sizes

    NASA Astrophysics Data System (ADS)

    Martínez-Castañón, G. A.; Niño-Martínez, N.; Martínez-Gutierrez, F.; Martínez-Mendoza, J. R.; Ruiz, Facundo

    2008-12-01

    Silver nanoparticles with different sizes (7, 29, and 89 nm mean values) were synthesized using gallic acid in an aqueous chemical reduction method. The nanoparticles were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), and ultraviolet-visible (UV-Vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopies studies (TEM) we observed that silver nanoparticles have spherical (7 and 29 nm) and pseudospherical shape (89 nm) with a narrow size distribution. The sizes of the silver nanoparticles were controlled by varying some experimental conditions. It was found that the antibacterial activity of the nanoparticles varies when their size diminishes.

  11. Chemiluminescent Reactions Catalyzed by Nanoparticles of Gold, Silver, and Gold/Silver Alloys

    NASA Astrophysics Data System (ADS)

    Abideen, Saqib Ul

    Chemiluminescence (CL) reactions are catalyzed by metals nanoparticles, which display unique catalytic properties due to an increased surface area. The present study describes the catalytic effects of nanoparticles (NP) of silver, gold, and alloys of Au/Ag nanoparticles on the chemiluminescent reaction taking place between luminol and potassium ferricyanide. It was found that silver nanoparticles and alloy nanoparticles enhance the CL process when their sizes remained in the range of 30 nm to 50 nm. The data show that the intensity and rate of chemiluminescence were influenced by the mole fraction of gold and silver in the alloy. Data to this chemiluminescence reaction are modeled by a double exponential curve, which indicates that two competing processes are occurring.

  12. Silver nanoparticle aggregation not triggered by an ionic strength mechanism

    NASA Astrophysics Data System (ADS)

    Botasini, Santiago; Méndez, Eduardo

    2013-04-01

    The synthesis of stable colloidal solutions of silver nanoparticles is a major goal in the industry to control their fate in aqueous solutions. The present work studies 10-20-nm silver nanoparticle aggregation triggered by the presence of chloride ions. The aggregation process was followed by UV-Vis-NIR spectroscopy and transmission electron microscopy. We found that the mechanism involved differs from the classic explanation of nanoparticle aggregation triggered by an increase in the ionic strength. Moreover, our results give evidence that even when nanoparticles are resistant to an increment of the total amount of ions, the formation of insoluble salts in the vicinity of the nanoparticle is enough to induce the aggregation. The presence of silver chloride around the silver nanoparticles was documented by an X-ray diffraction pattern and electrochemical methods because chloride anions are ubiquitous in real media; this alternative process jeopardized the development of many applications with silver nanoparticles that depend on the use of stable colloids.

  13. Use of a silver ion selective electrode to assess mechanisms responsible for biological effects of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Koch, Marcus; Kiefer, Silke; Cavelius, Christian; Kraegeloh, Annette

    2012-02-01

    For a detailed analysis of the biological effects of silver nanoparticles, discrimination between effects related to the nano-scale size of the particles and effects of released silver ions is required. Silver ions are either present in the initial particle dispersion or released by the nanoparticles over time. The aim of this study is to monitor the free silver ion activity {Ag+} in the presence of silver nanoparticles using a silver ion selective electrode. Therefore, silver in the form of silver nanoparticles, 4.2 ± 1.4 nm and 2-30 nm in size, or silver nitrate was added to cell culture media in the absence or presence of A549 cells as a model for human type II alveolar epithelial cells. The free silver ion activity measured after the addition of silver nanoparticles was determined by the initial ionic silver content. The p {Ag+} values indicated that the cell culture media decrease the free silver ion activity due to binding of silver ions by constituents of the media. In the presence of A549 cells, the free silver ion activity was further reduced. The morphology of A549 cells, cultivated in DME medium containing 9.1% (v/v) FBS, was affected by adding AgNO3 at concentrations of ≥30 μM after 24 h. In comparison, silver nanoparticles up to a concentration of 200 μM Ag did not affect cellular morphology. Our experiments indicate that the effect of silver nanoparticles is mainly mediated by silver ions. An effect of silver on cellular morphology was observed at p {Ag+} ≤ 9.2.

  14. Synthesis of silver nanoparticles: chemical, physical and biological methods

    PubMed Central

    Iravani, S.; Korbekandi, H.; Mirmohammadi, S.V.; Zolfaghari, B.

    2014-01-01

    Silver nanoparticles (NPs) have been the subjects of researchers because of their unique properties (e.g., size and shape depending optical, antimicrobial, and electrical properties). A variety of preparation techniques have been reported for the synthesis of silver NPs; notable examples include, laser ablation, gamma irradiation, electron irradiation, chemical reduction, photochemical methods, microwave processing, and biological synthetic methods. This review presents an overview of silver nanoparticle preparation by physical, chemical, and biological synthesis. The aim of this review article is, therefore, to reflect on the current state and future prospects, especially the potentials and limitations of the above mentioned techniques for industries. PMID:26339255

  15. Controlling the Shape and Crystallinity of Gold and Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Personick, Michelle Louise

    The strong dependence of the optical, electronic, and catalytic properties of noble metal nanoparticles on their shape has necessitated the high-yield synthesis of gold and silver nanostructures with precisely defined morphologies. This directed synthesis requires a detailed mechanistic understanding of the chemical and physical factors which control nanoparticle shape; however, these mechanistic explanations are still incomplete. To this end, the work of this dissertation seeks to enhance the understanding of nanoparticle growth on a mechanistic level, while also developing synthetic methods for producing novel nanoparticle shapes. Chapter 1 describes the state of the art in shape-controlled noble metal nanoparticle synthesis prior to the work conducted in this dissertation. In Chapter 2, a method is reported for synthesizing {110}-faceted bipyramids and rhombic dodecahedra, in which the combination of a chloride-containing surfactant and a low concentration of silver ions leads to the stabilization of the {110} facets. Chapter 3 explores in mechanistic detail the use of silver underpotential deposition to control particle growth in the synthesis of four gold nanoparticle shapes: octahedra, rhombic dodecahedra, truncated ditetragonal prisms, and concave cubes. This mechanistic understanding is expanded in Chapter 4, where the independent and synergistic roles of silver ions and halide ions in the seed-mediated synthesis of gold nanoparticles are systematically probed, culminating in a set of design considerations for controlling the shape of gold nanoparticles. Chapter 5 investigates the role of excitation wavelength in controlling the rate of silver ion reduction in the plasmon-mediated synthesis of silver nanoparticles and describes the synthesis of silver cubes with an unusual twinning structure. Finally, Chapter 6 combines the mechanistic insights gained in Chapters 2-5 to address a standing challenge in shape-controlled gold nanoparticle synthesis: the direct

  16. Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities

    PubMed Central

    Velusamy, Palaniyandi; Su, Chia-Hung; Venkat Kumar, Govindarajan; Adhikary, Shritama; Pandian, Kannaiyan; Gopinath, Subash C. B.; Chen, Yeng; Anbu, Periasamy

    2016-01-01

    In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications. PMID:27304672

  17. Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities.

    PubMed

    Velusamy, Palaniyandi; Su, Chia-Hung; Venkat Kumar, Govindarajan; Adhikary, Shritama; Pandian, Kannaiyan; Gopinath, Subash C B; Chen, Yeng; Anbu, Periasamy

    2016-01-01

    In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications.

  18. Silver nanoparticles delivery system based on natural rubber latex membranes

    NASA Astrophysics Data System (ADS)

    Guidelli, Éder José; Kinoshita, Angela; Ramos, Ana Paula; Baffa, Oswaldo

    2013-04-01

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV-Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane ( 0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.

  19. Detection and Quantification of Silver Nanoparticles at ...

    EPA Pesticide Factsheets

    The presence of silver nanoparticles (AgNPs) in aquatic environments could potentially cause adverse impacts on ecosystems and human health. However, current understanding of the environmental fate and transport of AgNPs is still limited because their properties in complex environmental samples cannot be accurately determined. In this study, the feasibility of using asymmetric flow field-flow fractionation (AF4) connected online with single particle inductively coupled plasma mass spectrometry (spICPMS) to detect and quantify AgNPs at environmentally relevant concentrations was investigated. The AF4 channel had a thickness of 350 μm and its accumulation wall was a 10 kDa regenerated cellulose membrane. A 0.02% FL-70 surfactant solution was used as an AF4 carrier. With 1.2 mL/min AF4 cross-flow rate, 1.5 mL/min AF4 channel flow rate, and 5 ms spICPMS dwell time, the AF4-spICPMS can detect and quantify 40–80 nm AgNPs, as well as Ag-SiO2 core−shell nanoparticles (51.0 nm diameter Ag core and 21.6 nm SiO2 shell), with good recovery within 30 min. This system was not only effective in differentiating and quantifying different types of AgNPs with similar hydrodynamic diameters, such as in mixtures containing Ag-SiO2 core–shell nanoparticles and 40–80 nm AgNPs, but also suitable for differentiating between 40 nm AgNPs and elevated Ag+ content. The study results indicate that AF4-spICPMS is capable of detecting and quantifying AgNPs and other engineered metal n

  20. Anti-proliferative activity of silver nanoparticles

    PubMed Central

    AshaRani, PV; Hande, M Prakash; Valiyaveettil, Suresh

    2009-01-01

    Background Nanoparticles possess exceptional physical and chemical properties which led to rapid commercialisation. Silver nanoparticles (Ag-np) are among the most commercialised nanoparticles due to their antimicrobial potential. Ag-np based cosmetics, therapeutic agents and household products are in wide use, which raised a public concern regarding their safety associated with human and environmental use. No safety regulations are in practice for the use of these nanomaterials. The interactions of nanomaterials with cells, uptake mechanisms, distribution, excretion, toxicological endpoints and mechanism of action remain unanswered. Results Normal human lung fibroblasts (IMR-90) and human glioblastoma cells (U251) were exposed to different doses of Ag-nps in vitro. Uptake of Ag-nps occurred mainly through endocytosis (clathrin mediated process and macropinocytosis), accompanied by a time dependent increase in exocytosis rate. The electron micrographs revealed a uniform intracellular distribution of Ag-np both in cytoplasm and nucleus. Ag-np treated cells exhibited chromosome instability and mitotic arrest in human cells. There was efficient recovery from arrest in normal human fibroblasts whereas the cancer cells ceased to proliferate. Toxicity of Ag-np is mediated through intracellular calcium (Ca2+) transients along with significant alterations in cell morphology and spreading and surface ruffling. Down regulation of major actin binding protein, filamin was observed after Ag-np exposure. Ag-np induced stress resulted in the up regulation of metallothionein and heme oxygenase -1 genes. Conclusion Here, we demonstrate that uptake of Ag-np occurs mainly through clathrin mediated endocytosis and macropinocytosis. Our results suggest that cancer cells are susceptible to damage with lack of recovery from Ag-np-induced stress. Ag-np is found to be acting through intracellular calcium transients and chromosomal aberrations, either directly or through activation of

  1. 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.

  2. 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

  3. Green synthesis of silver nanoparticles using fresh water green alga Pithophora oedogonia (Mont.) Wittrock and evaluation of their antibacterial activity

    NASA Astrophysics Data System (ADS)

    Sinha, Sankar Narayan; Paul, Dipak; Halder, Nilu; Sengupta, Dipta; Patra, Samir Kumar

    2015-08-01

    In the present study, we report the aqueous extract of Pithophora oedogonia to produce silver nanoparticles (AgNPs) by reduction of silver nitrate. It was noted that synthesis process was considerably rapid and silver nanoparticles were generated within few minutes of silver ions coming in contact with the algal extract. A peak at 445 nm corresponding to the plasmon absorbance of AgNPs was noted in the UV-vis spectrum of the aqueous medium that contained silver ions. Scanning electron microscopic (SEM) and dynamic light scattering analysis of colloidal AgNPs indicated the size of 34.03 nm. Energy-dispersive X-ray spectroscopy revealed strong signals in the silver region and confirmed of the AgNPs. Fourier transform infrared spectroscopic analysis of the nanoparticles indicated the presence of protein which was regarding a capping agent surrounding the AgNPs. Moreover, the antibacterial activity of synthesized nanoparticles exhibited potential inhibitory activity against seven tested pathogenic bacteria.

  4. Nanoparticle release from nano-silver antimicrobial food containers.

    PubMed

    Echegoyen, Yolanda; Nerín, Cristina

    2013-12-01

    Polymer nanocomposites incorporating metal or metal oxide nanoparticles have been developed to improve their characteristics (flexibility, gas barrier properties, antimicrobial or antioxidant properties, etc.). Among them silver nanoparticles are used because of their antimicrobial effect in many daily life materials, i.e. food packaging. However, there is not any reference to the migration of nanoparticles to the food. In this paper the results of migration studies (with different simulant solutions and times) in three commercial nanosilver plastic food containers are shown. Migration solutions were evaluated by ICP-MS and SEM-EDX analysis and silver in dissolved form and silver as nanoparticles were analyzed, a key aspect for the toxicity. Silver migration was observed for all samples studied, with the total silver migration values ranging between 1.66 and 31.46 ng/cm(2) (lower than the permissible limits). Size and morphology of the silver nanoparticles changed for the different samples (ranging between 10 and 60 nm) and migration of other nanosized materials was also confirmed.

  5. Silver Nanoparticles Synthesized Using Mint Extract and their Application in Chitosan/Gelatin Composite Packaging Film

    NASA Astrophysics Data System (ADS)

    Bhoir, Shraddha A.; Chawla, S. P.

    The present study reports synthesis of silver nanoparticles (AgNPs) using mint extract (ME) in the presence of polyvinyl alcohol (PVA) as capping material. PVA, ME and silver nitrate at concentration of 1%, 0.01% and 0.02%, respectively were found to be optimum for the synthesis of nanoparticles. The formation of AgNPs was confirmed by measuring surface plasmon resonance (SPR) peak. The intensity of SPR peak remained unaltered thus suggesting stability of colloid without aggregation during storage. The nanoparticles inhibited the growth of food borne bacteria namely Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus. The incorporation of these nanoparticles in chitosan and gelatin blend resulted in homogenous films. Mechanical properties and water vapor transmission rate of chitosan-gelatin films improved due to addition of AgNPs, whereas optical (opacity and UV light transmittance) and oxygen permeability properties remained unchanged. These films had the ability to inhibit growth of 5 log CFU of the above test organisms. These findings suggest that the AgNPs obtained by reduction of silver by ME can be effectively utilized to prepare antibacterial eco-friendly food packaging material.

  6. Robust one pot synthesis of colloidal silver nanoparticles by simple redox method and absorbance recovered sensing.

    PubMed

    Salman, Muhammad; Iqbal, Mahwish; El Ashry, El Sayed H; Kanwal, Shamsa

    2012-01-01

    Conventional synthesis of silver nanoparticles employs a reducing agent and a capping agent. In this report water-soluble silver nanoparticles (AgNPs) were prepared facilely by chemical reduction of Ag(I) ions. 4-Amino-3-(d-gluco-pentitol-1-yl)-4,5-dihydro-1,2,4-triazole-5-thione (AGTT) was used both as reducing and stabilizing agent. Direct heating methodology was found to be more suitable for achieving particles with a hydrodynamic diameter of ~20 nm. AGTT exists as tautomer in solution form and our studies indicate that -NH(2) group is involved in the reduction and stabilization of Ag(+) and thione (Δ=S) group of AGTT is possibly involved in stabilizing the nanoparticles via coordinate covalent linkage. Characterization of synthesized silver nanoparticles was performed by UV-vis, FT-IR and by FESEM. Based on the absorption properties of synthesized AgNPs, we used AgNPs to detect bovine serum albumin (BSA) and AgNPs-BSA composite nanoprobe was further applied to detect Cu(2+) based on absorbance recovery. The proposed method has advantages over existing methods in terms of rapid synthesis and stability of AgNPs and their applications. Analysis is reproducible, cost effective and highly sensitive. The lowest detectable concentration of BSA in this approach is 3 nM, and for Cu(2+) it can detect upto 200 pM.

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

    PubMed

    Cheviron, Perrine; Gouanvé, Fabrice; Espuche, Eliane

    2014-08-08

    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.

  8. The Use of chitosan in The Formation of Silver Nanoparticles, Chitosanic Nanoparticles and Fibrous Structures

    NASA Astrophysics Data System (ADS)

    Abdelgawad, Abdelrahman Mohamed

    Nanoscale materials have attracted much attention in the last two decades due to their unique properties. The size effect attains new chemical and physical properties to these materials. Nanoparticles and nanofiber are major component of nanomaterials and they have heavily investigated in the literature for different applications. Nanoparticles could be produced from both metals as well as polymers. Chitosan, which is a natural polymer, can be used as capping agent in the preparation of metallic nanoparticles and itself, can produce nanoparticles. The utilization of nanoparticles and nanofibers for wound dressing materials is a very popular approach. Acquiring antibacterial properties to the wound dressing materials could be obtained either by formulation of nanomaterials composites or direct chemical modification of the substance. To improve the antibacterial properties of chitosan two approaches were applied. First, is through the formulation of chitosan with silver nanoparticles and the formation of nanofiber mats. In this study, the concepts of green chemistry were applied and silver nanoparticles were prepared in high concentration using chitosan as a capping polymer and glucose as a reducing agent. Nanofiber mats of polyvinyl alcohol/chitosan/silvernanoparticles were produced via electrospinning. The antibacterial activity of these fibers shows bactericidal effect against E. coli at low concentrations of Ag-NPs. In the second approach, direct chemical modification of chitosan was performed by grafting of Iodoacetic acid to the amino group at carbon-2. The chemical structure of chitosan Iodoacetamide derivative (CIA) was confirmed by FTIR and H1-NMR. The derivative was amorphous and water soluble at neutral pH. The minimum inhibitory concentration of CIA, against E. coli, was 400ig/mL and the derivative was bacteriostatic after 4h of treatment. Nanofiber mats of polyvinyl alcohol/chitosan/chitosan Iodoacetamide were produced via electrospinning. The

  9. 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.

  10. 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.

  11. Biosynthesis of silver nanoparticles by using Ganoderma-mushroom extract

    NASA Astrophysics Data System (ADS)

    Ekar, S. U.; Khollam, Y. B.; Koinkar, P. M.; Mirji, S. A.; Mane, R. S.; Naushad, M.; Jadhav, S. S.

    2015-03-01

    Present study reports the biochemical synthesis of silver nanoparticles (Ag-NPs) from aqueous medium by using the extract of medicinal mushroom Ganoderma, as a reducing and stabilizing agents. The Ag-NPs are prepared at room temperature by the reduction of Ag+ to Ag in aqueous solution of AgNO3. The resultant particles are characterized by using UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) measurement techniques. The formation of Ag-NPs is confirmed by recording the UV-visible absorption spectra for surface plasmon resonance (SPR) where peak around 427 nm. The prominent changes observed in FTIR spectra supported the reduction of Ag+ to Ag. The morphological features of Ag-NPs are evaluated from HRTEM. The spherical Ag-NPs are observed in transmission electron microscopy (TEM) studies. The particle size distribution is found to be nearly uniform with average particle size of 2 nm. The Ag-NPs aged for 15, 30, 60 and 120 days showed no profound effect on the position of SPR peak in UV-visible studies, indicating the protecting/capping ability of medicinal mushroom Ganoderma in the synthesis of Ag-NPs.

  12. Antibacterial activity of silver nanoparticle-coated fabric and leather against odor and skin infection causing bacteria.

    PubMed

    Velmurugan, Palanivel; Lee, Sang-Myeong; Cho, Min; Park, Jung-Hee; Seo, Sang-Ki; Myung, Hyun; Bang, Keuk-Soo; Oh, Byung-Taek

    2014-10-01

    We present a simple, eco-friendly synthesis of silver and gold nanoparticles using a natural polymer pine gum solution as the reducing and capping agent. The pine gum solution was combined with silver nitrate (AgNO3) or a chloroauric acid (HAuCl4) solution to produce silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs), respectively. The reaction process was simple; formation of the nanoparticles was achieved by autoclaving the silver and gold ions with the pine gum. UV-Vis spectra showed surface plasmon resonance (SPR) for silver and gold nanoparticles at 432 and 539 nm, respectively. The elemental forms of AgNPs and AuNPs were confirmed by energy-dispersive X-ray spectroscopy (EDX). Fourier transform infrared spectroscopy (FTIR) showed the biomolecules present in the pine gum, AgNPs, and AuNPs. Transmission electron microscopy (TEM) images showed the shape and size of AgNPs and AuNPs. The crystalline nature of synthesized AgNPs and AuNPs was confirmed by X-ray crystallography [X-ray diffraction (XRD)]. Application of synthesized AgNPs onto cotton fabrics and leather, in order to evaluate their antibacterial properties against odor- or skin infection-causing bacteria, is also discussed. Among the four tested bacteria, AgNP-coated cotton fabric and leather samples displayed excellent antibacterial activity against Brevibacterium linens.

  13. New Paradigm Shift for the Green Synthesis of Antibacterial Silver Nanoparticles Utilizing Plant Extracts

    PubMed Central

    2014-01-01

    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

  14. 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.

  15. 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

    2015-01-01

    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.

  16. One-step synthesis and antibacterial property of water-soluble silver nanoparticles by CGJ bio-template

    NASA Astrophysics Data System (ADS)

    Zhu, Zi-Chun; Wu, Qing-Sheng; Chen, Ping; Yang, Xiao-Hong

    2011-10-01

    In this article, a new synthetic method of nanoparticles with fresh Chinese gooseberry juice (CGJ) as bio-template was developed. One-step synthesis of highly water-soluble silver nanoparticles at room temperature without using any harmful reducing agents and special capping agent was fulfilled with this method. In the process, the products were obtained by adding AgNO3 to CGJ, which was used as reducing agent, capping agent, and the bio-template. The products of silver nanoparticles with diameter of 10-30 nm have strong water solubility and excellent antibiotic function. With the same concentration 0.047 μg mL-1, the antibacterial effect of water-soluble silver particles by fresh CGJ was 53%, whereas only 27% for silver nanoparticles synthesized using the template method of fresh onion inner squama coat (OISC). The excellent water solubility of the products would enable them have better applications in the bio-medical field. The synthetic method would also have potential application in preparing other highly water-soluble particles, because of its simple apparatus, high yield, mild conditions, and facile operation.

  17. Agricultural waste Annona squamosa peel extract: Biosynthesis of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, Rajendran; Roopan, Selvaraj Mohana; Prabhakarn, Arunachalam; Khanna, Venkatesan Gopiesh; Chakroborty, Subhendu

    2012-05-01

    Development of reliable and eco-friendly process for the synthesis of metallic nanoparticles is an important step in the field of application of nanotechnology. We have developed modern method by using agriculture waste to synthesize silver nanoparticles by employing an aqueous peel extract of Annona squamosa in AgNO3. Controlled growth of silver nanoparticles was formed in 4 h at room temperature (25 °C) and 60 °C. AgNPs were irregular spherical in shape and the average particle size was about 35 ± 5 nm and it is consistent with particle size obtained by XRD Scherer equation.

  18. Agricultural waste Annona squamosa peel extract: biosynthesis of silver nanoparticles.

    PubMed

    Kumar, Rajendran; Roopan, Selvaraj Mohana; Prabhakarn, Arunachalam; Khanna, Venkatesan Gopiesh; Chakroborty, Subhendu

    2012-05-01

    Development of reliable and eco-friendly process for the synthesis of metallic nanoparticles is an important step in the field of application of nanotechnology. We have developed modern method by using agriculture waste to synthesize silver nanoparticles by employing an aqueous peel extract of Annona squamosa in AgNO(3). Controlled growth of silver nanoparticles was formed in 4h at room temperature (25°C) and 60°C. AgNPs were irregular spherical in shape and the average particle size was about 35±5 nm and it is consistent with particle size obtained by XRD Scherer equation.

  19. Laser synthesis and spectroscopy of acetonitrile/silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Akin, S. T.; Liu, X.; Duncan, M. A.

    2015-11-01

    Silver nanoparticles with acetonitrile ligands are produced in a laser ablation flow reactor. Excimer laser ablation produces gas phase metal clusters which are thermalized with helium or argon collisions in the flowtube, and reactions with acetonitrile vapor coordinate this ligand to the particle surface. The gaseous mixture is captured in a cryogenic trap; warming produces a solution of excess ligand and coated particles. TEM images reveal particle sizes of 10-30 nm diameter. UV-vis absorption and fluorescence spectra are compared to those of standard silver nanoparticles with surfactant coatings. Deep-UV ligand absorption is strongly enhanced by nanoparticle adsorption.

  20. Engineering Silver Nanoparticles: Towards a Tunable Antimicrobial

    NASA Astrophysics Data System (ADS)

    Puppala, Hema Lakshmi

    Overwhelming production of commercially available products containing silver nanoparticles (AgNPs) underscores the studies determining their fate in the environment. In order to regulate the use, assess the environmental impact and develop eco-responsible silver products, models that can predict AgNP toxicity based on physicochemical properties are vital. With that vision, this thesis developed well-characterized model libraries of uniform AgNPs stabilized with oleate in the range of 2-45 nm diameter with variable surface coating and investigated the dissolution properties that link AgNP structure to antimicrobial activity. High temperature organic synthesis allowed controlled growth of AgNPs (sigma<15%) by an Ostwald ripening mechanism in the first few hours, and followed by size dependent growth rates yielding uniform nanocrystals. Characterization of these materials revealed a crystalline nature, bidentate binding mode of oleate and non-oxidized pristine silver surface. Phase transfer of these AgNPs from organics to water was facilitated by encapsulation and ligand exchange methods using amphiphilic polymers and methoxy poly (ethylene glycol) (mPEGSH) respectively. Among these surface coatings, steric stabilization by mPEGSH not only helped retain their optical properties but also reduced the dissolution (<1(w/w)%) of AgNPs. This enhanced the stability in various environmentally relevant high ionic strength media (such as Hoaglands, EPA hard water and OECD medium), thereby increasing the shelf life. In addition, size, surface coating, pH of the medium and grafting density of the polymer mediated the dissolution of AgNPs. For instance, the rate of dissolution was decreased by 40% when the polymer coating possessed a mushroom conformation and increased with reducing core size. Analogous to dissolution, physicochemical properties also influenced the antimicrobial activity which were studied by minimum inhibitory concentration (MIC) and bactericidal efficacy assays

  1. One-step synthesis of silver nanoparticles, nanorods, and nanowires on the surface of DNA network.

    PubMed

    Wei, Gang; Zhou, Hualan; Liu, Zhiguo; Song, Yonghai; Wang, Li; Sun, Lanlan; Li, Zhuang

    2005-05-12

    Here, we describe a one-step synthesis of silver nanoparticles, nanorods, and nanowires on DNA network surface in the absence of surfactant. Silver ions were first adsorbed onto the DNA network and then reduced in sodium borohydride solution. Silver nanoparticles, nanorods, and nanowires were formed by controlling the size of pores of the DNA network. The diameter of the silver nanoparticles and the aspect ratio of the silver nanorods and nanowires can be controlled by adjusting the DNA concentration and reduction time.

  2. Thermo-optical properties of embedded silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Rashidi Huyeh, M.; Shirdel Havar, M.; Palpant, B.

    2012-11-01

    Thermo-optical properties of nanocomposite materials consisting of noble metal nanoparticles dispersed in a dielectric medium are appropriate for many applications as imaging, nonlinear optics, or optical monitoring of local thermal exchanges. Here, we analyze the thermo-optical response of silver nanoparticles. The contribution of inter- and intraband transitions to the thermo-optical index of bulk silver is first extracted using experimental results reported earlier in the literature. The influence of these two contributions on the thermo-optical properties of silver nanoparticles embedded in glass is then investigated. The results show that these properties are essentially due to the intraband thermo-optical contribution in the vicinity of the surface plasmon resonance of the nanoparticles, while they are dominated by the interband contribution close to the interband transition threshold.

  3. 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.

  4. PVP-coated, negatively charged silver nanoparticles: A multi-center study of their physicochemical characteristics, cell culture and in vivo experiments

    PubMed Central

    Ahlberg, Sebastian; Antonopulos, Alexandra; Diendorf, Jörg; Dringen, Ralf; Flöck, Rebekka; Goedecke, Wolfgang; Graf, Christina; Haberl, Nadine; Helmlinger, Jens; Herzog, Fabian; Heuer, Frederike; Hirn, Stephanie; Johannes, Christian; Kittler, Stefanie; Köller, Manfred; Korn, Katrin; Kreyling, Wolfgang G; Krombach, Fritz; Lademann, Jürgen; Loza, Kateryna; Luther, Eva M; Malissek, Marcelina; Meinke, Martina C; Nordmeyer, Daniel; Pailliart, Anne; Raabe, Jörg; Rancan, Fiorenza; Rothen-Rutishauser, Barbara; Rühl, Eckart; Schleh, Carsten; Seibel, Andreas; Sengstock, Christina; Treuel, Lennart; Vogt, Annika; Weber, Katrin; Zellner, Reinhard

    2014-01-01

    Summary PVP-capped silver nanoparticles with a diameter of the metallic core of 70 nm, a hydrodynamic diameter of 120 nm and a zeta potential of −20 mV were prepared and investigated with regard to their biological activity. This review summarizes the physicochemical properties (dissolution, protein adsorption, dispersability) of these nanoparticles and the cellular consequences of the exposure of a broad range of biological test systems to this defined type of silver nanoparticles. Silver nanoparticles dissolve in water in the presence of oxygen. In addition, in biological media (i.e., in the presence of proteins) the surface of silver nanoparticles is rapidly coated by a protein corona that influences their physicochemical and biological properties including cellular uptake. Silver nanoparticles are taken up by cell-type specific endocytosis pathways as demonstrated for hMSC, primary T-cells, primary monocytes, and astrocytes. A visualization of particles inside cells is possible by X-ray microscopy, fluorescence microscopy, and combined FIB/SEM analysis. By staining organelles, their localization inside the cell can be additionally determined. While primary brain astrocytes are shown to be fairly tolerant toward silver nanoparticles, silver nanoparticles induce the formation of DNA double-strand-breaks (DSB) and lead to chromosomal aberrations and sister-chromatid exchanges in Chinese hamster fibroblast cell lines (CHO9, K1, V79B). An exposure of rats to silver nanoparticles in vivo induced a moderate pulmonary toxicity, however, only at rather high concentrations. The same was found in precision-cut lung slices of rats in which silver nanoparticles remained mainly at the tissue surface. In a human 3D triple-cell culture model consisting of three cell types (alveolar epithelial cells, macrophages, and dendritic cells), adverse effects were also only found at high silver concentrations. The silver ions that are released from silver nanoparticles may be harmful

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

    PubMed Central

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

    2015-01-01

    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

  6. 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.

  7. Curcumin modified silver nanoparticles for highly efficient inhibition of respiratory syncytial virus infection

    NASA Astrophysics Data System (ADS)

    Yang, Xiao Xi; Li, Chun Mei; Huang, Cheng Zhi

    2016-01-01

    Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition effect against respiratory syncytial virus (RSV) infection, giving a decrease of viral titers about two orders of magnitude at the concentration of cAgNPs under which no toxicity was found to the host cells. Mechanism investigations showed that cAgNPs could prevent RSV from infecting the host cells by inactivating the virus directly, indicating that cAgNPs are a novel promising efficient virucide for RSV.Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition

  8. Plant extract-mediated biogenic synthesis of silver, manganese dioxide, silver-doped manganese dioxide nanoparticles and their antibacterial activity against food- and water-borne pathogens.

    PubMed

    Krishnaraj, Chandran; Ji, Byoung-Jun; Harper, Stacey L; Yun, Soon-Il

    2016-05-01

    Silver nanoparticles (AgNPs), manganese dioxide nanoparticles (MnO₂NPs) and silver-doped manganese dioxide nanoparticles (Ag-doped MnO₂NPs) were synthesized by simultaneous green chemistry reduction approach. Aqueous extract from the leaves of medicinally important plant Cucurbita pepo was used as reducing and capping agents. Various characterization techniques were carried out to affirm the formation of nanoparticles. HR-TEM analysis confirmed the size of nanoparticles in the range of 15-70 nm and also metal doping was confirmed through XRD and EDS analyses. FT-IR analysis confirmed that the presence of biomolecules in the aqueous leaves extract was responsible for nanoparticles synthesis. Further, the concentration of metals and their doping in the reaction mixture was achieved by ICP-MS. The growth curve and well diffusion study of synthesized nanoparticles were performed against food- and water-borne Gram-positive and Gram-negative bacterial pathogens. The mode of interaction of nanoparticles on bacterial cells was demonstrated through Bio-TEM analysis. Interestingly, AgNPs and Ag-doped MnO₂NPs showed better antibacterial activity against all the tested bacterial pathogens; however, MnO₂NPs alone did not show any antibacterial properties. Hence, AgNPs and Ag-doped MnO₂NPs synthesized from aqueous plant leaves extract may have important role in controlling various food spoilage caused by bacteria.

  9. Formation of catalytic silver nanoparticles supported on branched polyethyleneimine derivatives.

    PubMed

    Signori, Aline M; Santos, Kelly de O; Eising, Renato; Albuquerque, Brunno L; Giacomelli, Fernando C; Domingos, Josiel B

    2010-11-16

    A new and straightforward method for screening highly catalytically active silver nanoparticle-polymer composites derived from branched polyethyleneimine (PEI) is reported. The one-step systematic derivatization of the PEI scaffold with alkyl (butyl or octyl) and ethanolic groups led to a structural diversity correlated to the stabilization of silver nanoparticles and catalysis. Analysis of PEI derivative libraries identified a silver nanoparticle-polymer composite that was able to efficiently catalyze the p-nitrophenol reduction by NaBH(4) in water with a rate constant normalized to the surface area of the nanoparticles per unit volume (k(1)) of 0.57 s(-1) m(-2) L. Carried out in the presence of excess NaBH(4), the catalytic reaction was observed to follow pseudo-first-order kinetics and the apparent rate constant was linearly dependent on the total surface area of the silver nanoparticles (Ag-NPs), indicating that catalysis takes place on the surface of the nanoparticles. All reaction kinetics presented induction periods, which were dependent on the concentration of substrates, the total surface of the nanoparticles, and the polymer composition. All data indicated that this induction time is related to the resistance to substrate diffusion through the polymer support. Hydrophobic effects are also assumed to play an important role in the catalysis, through an increase in the local substrate concentration.

  10. Silver Nanoparticle Paste for Low-Temperature Bonding of Copper

    NASA Astrophysics Data System (ADS)

    Alarifi, Hani; Hu, Anming; Yavuz, Mustafa; Zhou, Y. Norman

    2011-06-01

    Silver nanoparticle (NP) paste was fabricated and used to bond copper wire to copper foil at low temperatures down to 160°C. The silver NP paste was developed by increasing the concentration of 50 nm silver NP sol from 0.001 vol.% to 0.1 vol.% by centrifugation. The 0.001 vol.% silver NP sol was fabricated in water by reducing silver nitrate (AgNO3) using sodium citrate dihydrate (Na3C6H5O7·2H2O). The bond was formed by solid-state sintering among the individual silver NPs and solid-state bonding of these silver NPs onto both copper wire and foil. Metallurgical bonds between silver NPs and copper were confirmed by transmission electron microscopy (TEM). The silver NPs were coated with an organic shell to prevent sintering at room temperature (RT). It was found that the organic shell decomposed at 160°C, the lowest temperature at which a bond could be formed. Shear tests showed that the joint strength increased as the bonding temperature increased, due to enhanced sintering of silver NPs at higher temperatures. Unlike low-temperature soldering techniques, bonds formed by our method have been proved to withstand temperatures above the bonding temperature.

  11. RIR-MAPLE deposition of plasmonic silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Ge, Wangyao; Hoang, Thang B.; Mikkelsen, Maiken H.; Stiff-Roberts, Adrienne D.

    2016-09-01

    Nanoparticles are being explored in many different applications due to the unique properties offered by quantum effects. To broaden the scope of these applications, the deposition of nanoparticles onto substrates in a simple and controlled way is highly desired. In this study, we use resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) for the deposition of metallic, silver nanoparticles for plasmonic applications. We find that RIR-MAPLE, a simple and versatile approach, is able to deposit silver nanoparticles as large as 80 nm onto different substrates with good adhesion, regardless of substrate properties. In addition, the nanoparticle surface coverage of the substrates, which result from the random distribution of nanoparticles across the substrate per laser pulse, can be simply and precisely controlled by RIR-MAPLE. Polymer films of poly(3-hexylthiophene-2,5-diyl) (P3HT) are also deposited by RIR-MAPLE on top of the deposited silver nanoparticles in order to demonstrate enhanced absorption due to the localized surface plasmon resonance effect. The reported features of RIR-MAPLE nanoparticle deposition indicate that this tool can enable efficient processing of nanoparticle thin films for applications that require specific substrates or configurations that are not easily achieved using solution-based approaches.

  12. Effect of silver nanoparticles on concentration of silver heavy element and growth indexes in cucumber ( Cucumis sativus L . negeen)

    NASA Astrophysics Data System (ADS)

    Shams, Gholamabbas; Ranjbar, Morteza; Amiri, Aliasghar

    2013-05-01

    The tremendous progress on nanoparticle research area has been made significant effects on the economy, society, and the environment. Silver nanoparticle is one of the most important particles in these categories. Silver nanoparticles can be converted to the heavy silver metal in water by oxidation. Moreover, in the high amounts of silver concentration, they will be accumulated in different parts of the plant. However, by changing the morphology of the plant, the production will be harmful for human consumptions. In this study, nano-powders with average 50 nm silver particles are mixed with deionized distilled water in a completely randomized design. Seven treatments with various concentrations of suspension silver nanoparticles were prepared and repeated in four different parts of the plant in a regular program of spraying. Samples were analyzed to study the growth indexes and concentration of silver in different parts of the plant. It was observed that with increasing concentration of silver nanoparticles on cucumber, the growth indexes (except pH fruit), and the concentration of silver heavy metal are increased significantly. The incremental concentration had the linear relationship with correlation coefficient 0.95 and an average of 0.617 PPM by increasing of each unit in one thousand concentration of nanosilver. Although, by increasing concentration of silver nanoparticles as spraying form, the plant morphological characteristics were improved, the concentration of silver heavy metal in various plant organs was increased. These results open a new pathway to consider the effect of nanoparticles on plant's productions for human consumptions.

  13. Production of silver ions from colloidal silver by nanoparticle iontophoresis system.

    PubMed

    Tseng, Kuo-Hsiung; Liao, Chih-Yu

    2011-03-01

    Metal ions, especially the silver ion, were used to treat infection before the initiation of antibiotic therapy. Unfortunately, there is a lack of research on the metallic nanoparticle suspension as a reservoir for metal ion release application. For medical purposes, conversion of colloidal silver into an ionic form is necessary, but not using silver salts (e.g., AgNO3, Ag2SO4), due to the fact that the counter-ion of silver salts may cause problems to the body as the silver ion (Ag+) is consumed. The goal of this research is to develop a silver nanoparticle iontophoresis system (NIS) which can provide a relatively safe bactericidal silver ion solution with a controllable electric field. In this study, ion-selective electrodes were used to identify and observe details of the system's activity. Both qualitative and quantitative data analyses were performed. The experimental results show that the ion releasing peak time (R(PT)) has an inversely proportional relationship with the applied current and voltage. The ion releasing maximum level (R(ML)) and dosage (R(D)) are proportional to the current density and inversely proportional to the voltage, respectively. These results reveal that the nanoparticle iontophoresis system (NIS) is an alternative method for the controlled release of a metal ion and the ion's concentration profile, by controlling the magnitude of current density (1 microA/cm2 equal to 1 ppm/hour) and applied voltage.

  14. Immobilization of silver nanoparticles on silica microspheres

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Kai; Chen, Chia-Yin; Han, Jin-Lin; Chen, Chii-Chang; Jiang, Meng-Dan; Hsu, Jen-Sung; Chan, Chia-Hua; Hsieh, Kuo-Huang

    2010-01-01

    The silver nanoparticles (Ag NPs) have been immobilized onto silica microspheres through the adsorption and subsequent reduction of Ag+ ions on the surfaces of the silica microspheres. The neat silica microspheres that acted as the core materials were prepared through sol-gel processing; their surfaces were then functionalized using 3-mercaptopropyltrimethoxysilane (MPTMS). The major aims of this study were to immobilize differently sized Ag particles onto the silica microspheres and to understand the mechanism of formation of the Ag nano-coatings through the self-assembly/adsorption behavior of Ag NPs/Ag+ ions on the silica spheres. The obtained Ag NP/silica microsphere conglomerates were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS). Their electromagnetic wave shielding effectiveness were also tested and studied. The average particle size of the obtained Ag NPs on the silica microsphere was found that could be controllable (from 2.9 to 51.5 nm) by adjusting the ratio of MPTMS/TEOS and the amount of AgNO3.

  15. Fate of Silver Nanoparticles in Lake Mesocosms

    NASA Astrophysics Data System (ADS)

    Furtado, Lindsay

    The fate of silver nanoparticles (AgNPs) in surface waters determines the ecological risk of this emerging contaminant. In this research, the fate of AgNPs in lake mesocosms was studied using both a continuous (i.e. drip) and one-time (i.e. plug) dosing regime. AgNPs were persistent in the tested lake environment as there was accumulation in the water column over time in drip mesocosms and slow dissipation from the water column (half life of 20 days) in plug mesocosms. In drip mesocosms, AgNPs were found to accumulate in the water column, periphtyon, and sediment according to loading rate; and, AgNP coating (PVP vs. CT) had no effect on agglomeration and dissolution based on filtration analysis. In plug mesocosms, cloud point extraction (CPE), single-particle-inductively coupled mass spectroscopy (spICP-MS), and asymmetrical flow field-flow fractionation (AF4-ICP-MS) confirmed the temporal dissolution of AgNPs into Ag+ over time; however, complexation is expected to reduce the toxicity of Ag + in natural waters.

  16. Low temperature plasma sintering of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Ma, Siyuan; Bromberg, Vadim; Liu, Liang; Egitto, Frank D.; Chiarot, Paul R.; Singler, Timothy J.

    2014-02-01

    The fabrication of flexible electronics using the deposition of solution-processed nanomaterials generally requires low-temperature post-processing to optimize functionality. We studied sintering of silver nanoparticle (AgNP) films on glass substrates by applying argon (Ar) plasma to achieve improved electrical conductivity. This process meets the low temperature processing requirements for standard low-cost polymeric flexible substrates. The relationship between plasma parameters (such as power and sintering time) versus sintering results (such as electrical sheet resistance, sintered structure depth, materials composition variation, and film nanostructure) is reported for 23 and 77 nm diameter AgNPs. In addition, plasma processing typically induces a small surface thermal effect. We monitored the surface temperatures of the AgNP films in-situ during plasma sintering. By sintering control groups at these monitored surface temperatures using a vacuum oven, we confirmed that the resistivity due to plasma sintering is less than that produced by thermal sintering. Our data show that, the measured lowest resistivities for plasma sintered AgNP films are about only 5 and 12 times greater than the bulk Ag resistivity for 23 and 77 nm, respectively.

  17. Catalytic degradation of organic dyes using biosynthesized silver nanoparticles.

    PubMed

    Vidhu, V K; Philip, Daizy

    2014-01-01

    The green synthesis of metallic nanoparticles paved the way to improve and protect the environment by decreasing the use of toxic chemicals and eliminating biological risks in biomedical applications. Plant mediated synthesis of metal nanoparticles is gaining more importance owing to its simplicity, rapid rate of synthesis of nanoparticles and eco-friendliness. The present article reports an environmentally benign and unexploited method for the synthesis of silver nanocatalysts using Trigonella foenum-graecum seeds, which is a potential source of phytochemicals. The UV-visible absorption spectra of the silver samples exhibited distinct band centered around 400-440 nm. The major phytochemicals present in the seed extract responsible for the formation of silver nanocatalysts are identified using FTIR spectroscopy. The report emphasizes the effect of the size of silver nanoparticles on the degradation rate of hazardous dyes, methyl orange, methylene blue and eosin Y by NaBH4. The efficiency of silver nanoparticles as a promising candidate for the catalysis of organic dyes by NaBH4 through the electron transfer process is established in the present study.

  18. Green synthesis of silver nanoparticles as antibacterial agent using Rhodomyrtus tomentosa acetone extract

    NASA Astrophysics Data System (ADS)

    Voravuthikunchai, Supayang P.; Chorachoo, Julalak; Jaiswal, Lily; Shankar, Shiv

    2013-12-01

    The capability of Rhodomyrtus tomentosa acetone extract (RAE) for the production of silver nanoparticles (AgNPs) has been explored for the first time. Silver nanoparticles with a surface plasmon resonance band centered at 420-430 nm were synthesized by reacting RAE with AgNO3. Reaction time, temperature, concentration of AgNO3 and RAE could accelerate the reduction rate of Ag+ and affect AgNPs size. The nanoparticles were found to be 10-30 nm in size and spherical in shape. XRD data demonstrated crystalline nature of AgNPs dominated by (200) facets. FTIR results showed decrease in intensity of peaks at 3394, 1716 and 1618 cm-1 indicating the involvement of O-H, carbonyl group and C=C stretching with the formation of AgNPs with RAE, respectively. The C-O-C and C-N stretching suggested the presence of many phytochemicals on the surface of the nanoparticles. High negative zeta potential values confirmed the stability of AgNPs in water. In vitro antibacterial activity of AgNPs was tested against Staphylococcus aureus using broth microdilution method. AgNPs capped with RAE demonstrated profound antibacterial activity against the organisms with minimum inhibitory concentration and minimum bactericidal concentration in the range between 3.1-6.2 and 6.2-50 μgmL-1, respectively. The synthesized nanoparticles could be applied as an effective antimicrobial agent against staphylococcal infections.

  19. Synthesis of copper nanoparticles catalyzed by pre-formed silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Grouchko, Michael; Kamyshny, Alexander; Ben-Ami, Keren; Magdassi, Shlomo

    2009-04-01

    Synthesis of well dispersed copper nanoparticles was achieved by reduction of copper nitrate in aqueous solution using hydrazine monohydrate as a reducer in the presence of preformed silver nanoparticles as catalysts. It has been demonstrated that addition of silver nanoparticles to the reaction mixture leads to formation of aqueous dispersion of copper nanoparticles and also results in a drastic reduction in reaction time compared to procedures reported in the literature. The absorption spectrum of the dispersions, HR-TEM and STEM images and XRD pattern indicate the formation of copper nanoparticles with particle size in the range of 5-50 nm.

  20. 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...

  1. Silver Nanoparticle Generators: Silicon Dioxide Microspheres.

    PubMed

    Liu, Yan; Li, Yingdi; Kang, Yanlei; Shen, Qihui; Liu, Xiaoyang; Zhou, Jianguang

    2017-02-24

    A green and simple approach has been developed to synthesize un-coated Ag nanoparticles (AgNPs) in situ on the surface of thiol-group-functionalized silica dioxide microspheres (TSMs) in the aqueous solution. As soon as the Ag(+) ions attach onto the surface of TSMs, nucleation and growth of AgNPs can spontaneously complete within one minute without other reducing agents or capping agents. The main reason is that the self-assembled silane-layer formed by mercaptosilane molecules could reduce the Ag(0) formation energy, transport electrons efficiently, improve the nucleation density, and protect AgNPs against oxidation. Thus, the supported AgNPs show excellent chemical/photochemical stability in air and solution. Meanwhile, the size of as-prepared AgNPs could be controlled by tuning the concentration of Ag(+) ions. This process provides a general route to generate bare AgNPs on the surface of silica dioxide in situ, which might be extended to other materials and is promising in developing novel methodologies for making supported noble metal NPs with desired structure and properties.

  2. Green engineered biomolecule-capped silver and copper nanohybrids using Prosopis cineraria leaf extract: Enhanced antibacterial activity against microbial pathogens of public health relevance and cytotoxicity on human breast cancer cells (MCF-7).

    PubMed

    Jinu, U; Gomathi, M; Saiqa, I; Geetha, N; Benelli, G; Venkatachalam, P

    2017-04-01

    This research focused on green engineering and characterization of silver (PcAgNPs) and copper nanoparticles (PcCuNPs) using Prosopis cineraria (Pc) leaf extract prepared by using microwave irradiation. We studied their enhanced antimicrobial activity on human pathogens as well as cytotoxicity on breast cancer cells (MCF-7). Biofabricated silver and copper nanoparticles exhibited UV-Visible absorbance peaks at 420 nm and 575 nm, confirming the bioreduction and stabilization of nanoparticles. Nanoparticles were characterized by FTIR, XRD, FESEM, and EDX analysis. FTIR results indicated the presence of alcohols, alkanes, aromatics, phenols, ethers, benzene, amines and amides that were possibly involved in the reduction and capping of silver and copper ions. XRD analysis was performed to confirm the crystalline nature of the silver and copper nanoparticles. FESEM analysis suggested that the nanoparticles were hexagonal or spherical in shape with size ranging from 20 to 44.49 nm and 18.9-32.09 nm for AgNPs and CuNPs, respectively. EDX analysis confirmed the presence of silver and copper elemental signals in the nanoparticles. The bioengineered silver and copper nanohybrids showed enhanced antimicrobial activity against Gram-positive and Gram-negative MDR human pathogens. MTT assay results indicated that CuNPs show potential cytotoxic effect followed by AgNPs against MCF-7 cancer cell line. IC50 were 65.27 μg/ml, 37.02 μg/ml and 197.3 μg/ml for PcAgNPs, PcCuNPs and P. cineraria leaf extracts, respectively, treated MCF-7 cells. The present investigation highlighted an effective protocol for microwave-assisted synthesis of biomolecule-loaded silver and copper nanoparticles with enhanced antibacterial and anticancer activity. Results strongly suggested that bioengineered AgNPs and CuNPs could be used as potential tools against microbial pathogens and cancer cells.

  3. Antithrombotic functions of small molecule-capped gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Tian, Yue; Zhao, Yuyun; Zheng, Wenfu; Zhang, Wei; Jiang, Xingyu

    2014-07-01

    Here we report the antithrombotic functions of pyrimidinethiol-capped gold nanoparticles (Au_DAPT NPs). They can prolong coagulation parameters when injected intravenously in normal mice. Applied in two typical thrombosis models, mice tail thrombosis and pulmonary thromboembolism, gold NPs can inhibit both thrombosis and improve the survival rates of mice tremendously, without increasing the bleeding risk. The anticoagulant mechanisms include inhibiting the platelet aggregation as well as interfering with thrombin and fibrin generation.Here we report the antithrombotic functions of pyrimidinethiol-capped gold nanoparticles (Au_DAPT NPs). They can prolong coagulation parameters when injected intravenously in normal mice. Applied in two typical thrombosis models, mice tail thrombosis and pulmonary thromboembolism, gold NPs can inhibit both thrombosis and improve the survival rates of mice tremendously, without increasing the bleeding risk. The anticoagulant mechanisms include inhibiting the platelet aggregation as well as interfering with thrombin and fibrin generation. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr01937g

  4. Synthesis and optical properties of silver nanoparticles and arrays.

    PubMed

    Evanoff, David D; Chumanov, George

    2005-07-11

    This Minireview systematically examines optical properties of silver nanoparticles as a function of size. Extinction, scattering, and absorption cross-sections and distance dependence of the local electromagnetic field, as well as the quadrupolar coupling of 2D assemblies of such particles are experimentally measured for a wide range of particle sizes. Such measurements were possible because of the development of a novel synthetic method for the size-controlled synthesis of chemically clean, highly crystalline silver nanoparticles of narrow size distribution. The method and its unique advantages are compared to other methods for synthesis of metal nanoparticles. Synthesis and properties of nanocomposite materials using these and other nanoparticles are also described. Important highlights in the history of the field of metal nanoparticles as well as an examination of the basic principles of plasmon resonances are included.

  5. 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

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

    PubMed

    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.

  7. Silver nanoparticles with gelatin nanoshells: photochemical facile green synthesis and their antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Pourjavadi, Ali; Soleyman, Rouhollah

    2011-10-01

    In the current study, a facile green synthesis of silver-gelatin core-shell nanostructures (spherical, spherical/cubic hybrid, and cubic, DLS diameter: 4.1-6.9 nm) is reported via the wet chemical synthesis procedure. Sunlight-UV as an available reducing agent cause mild reduction of silver ions into the silver nanoparticles (Ag-NPs). Gelatin protein, as an effective capping/shaping agent, was used in the reaction to self-assemble silver nanostructures. The formation of silver nanostructures and their self-assembly pattern was confirmed by SEM, AFM, and TEM techniques. Further investigations were carried out using zeta-potential, UV-Vis, FTIR, GPC, and TGA/DTG/DTA data. The prepared Ag-NPs showed proper and acceptable antimicrobial activity against three classes of microorganisms ( Escherichia coli Gram-negative bacteria, Staphylococcus aureus Gram-positive bacteria, and Candida albicans fungus). The antibacterial and antifungal Ag-NPs exhibit good stability in solution and can be considered as promising candidates for a wide range of biomedical applications.

  8. Nanoscale self-arranged layers of silver nanoparticles in glass

    NASA Astrophysics Data System (ADS)

    Redkov, Alexey V.; Lipovskii, Andrey A.; Dussauze, Marc; Paraillous, Maxime; Cardinal, Thierry

    2016-05-01

    We characterized changes in the composition of subsurface layer of silver ion-exchanged soda-lime glass during annealing in hydrogen atmosphere. The formation of tens of nanometers distanced layers of silver nanoparticles in the glass at temperature of 300 °C has been revealed. Performed numerical modeling of the process demonstrates a good qualitative agreement with the experiment. This is of interest for simple formation of 3D-optoplasmonic structures, Bragg gratings or photonic crystals.

  9. Evolution of silver nanoparticles in the rat lung investigated by X-ray absorption spectroscopy

    SciTech Connect

    Davidson, R. Andrew; Anderson, Donald S.; Van Winkle, Laura S.; Pinkerton, Kent E.; Guo, T.

    2014-12-16

    Following a 6-h inhalation exposure to aerosolized 20 and 110 nm diameter silver nanoparticles, lung tissues from rats were investigated with X-ray absorption spectroscopy, which can identify the chemical state of silver species. Lung tissues were processed immediately after sacrifice of the animals at 0, 1, 3, and 7 days post exposure and the samples were stored in an inert and low-temperature environment until measured. We found that it is critical to follow a proper processing, storage and measurement protocol; otherwise only silver oxides are detected after inhalation even for the larger nanoparticles. The results of X-ray absorption spectroscopy measurements taken in air at 85 K suggest that the dominating silver species in all the postexposure lung tissues were metallic silver, not silver oxide, or solvated silver cations. The results further indicate that the silver nanoparticles in the tissues were transformed from the original nanoparticles to other forms of metallic silver nanomaterials and the rate of this transformation depended on the size of the original nanoparticles. Furthermore, we found that 20 nm diameter silver nanoparticles were significantly modified after aerosolization and 6-h inhalation/deposition, whereas larger, 110 nm diameter nanoparticles were largely unchanged. Over the seven-day postexposure period the smaller 20 nm silver nanoparticles underwent less change in the lung tissue than the larger 110 nm silver nanoparticles. In contrast, silica-coated gold nanoparticles did not undergo any modification processes and remained as the initial nanoparticles throughout the 7-day study period.

  10. Evolution of Silver Nanoparticles in the Rat Lung Investigated by X-ray Absorption Spectroscopy

    PubMed Central

    2015-01-01

    Following a 6-h inhalation exposure to aerosolized 20 and 110 nm diameter silver nanoparticles, lung tissues from rats were investigated with X-ray absorption spectroscopy, which can identify the chemical state of silver species. Lung tissues were processed immediately after sacrifice of the animals at 0, 1, 3, and 7 days post exposure and the samples were stored in an inert and low-temperature environment until measured. We found that it is critical to follow a proper processing, storage and measurement protocol; otherwise only silver oxides are detected after inhalation even for the larger nanoparticles. The results of X-ray absorption spectroscopy measurements taken in air at 85 K suggest that the dominating silver species in all the postexposure lung tissues were metallic silver, not silver oxide, or solvated silver cations. The results further indicate that the silver nanoparticles in the tissues were transformed from the original nanoparticles to other forms of metallic silver nanomaterials and the rate of this transformation depended on the size of the original nanoparticles. We found that 20 nm diameter silver nanoparticles were significantly modified after aerosolization and 6-h inhalation/deposition, whereas larger, 110 nm diameter nanoparticles were largely unchanged. Over the seven-day postexposure period the smaller 20 nm silver nanoparticles underwent less change in the lung tissue than the larger 110 nm silver nanoparticles. In contrast, silica-coated gold nanoparticles did not undergo any modification processes and remained as the initial nanoparticles throughout the 7-day study period. PMID:25517690

  11. Photocurrent enhancement in polythiophene doped with silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Szeremeta, Janusz; Nyk, Marcin; Samoc, Marek

    2014-11-01

    We studied the spectral dependence of the influence of silver nanoparticles (Ag NPs) on the photoconductivity of poly(3-hexylthiophene) (P3HT) thin films. 7 ± 2 nm silver nanoparticles were synthesized by thermal decomposition of an organometallic silver salt in organic solvent. Optical properties of the mixture of P3HT and Ag NPs and thin films with various Ag content were investigated. Spectral dependences of the photocurrent were measured for the films cast on the top of interdigitated microelectrodes. Antibatic behavior of the photocurrent with respect to the absorption spectrum was observed. Results shows 40-150 times enhancement of the photocurrents, depending on the wavelength, in films doped with Ag NPs compared with the pristine films. The existing theories on the influence of metallic nanoparticles in the photoactive layer of organic solar cells are reviewed and discussed.

  12. Fungicidal activity of silver nanoparticles against Alternaria brassicicola

    NASA Astrophysics Data System (ADS)

    Gupta, Deepika; Chauhan, Pratima

    2016-04-01

    This work highlighted the fungicidal properties of silver nanoparticles against Alternaria brassicicola. Alternaria brassicicola causes Black spot of Cauliflower, radish, cabbage, kale which results in sever agricultural loss. We treat the synthesised silver nanoparticles (AgNPs) of 10, 25, 50, 100 and 110 ppm concentrations against Alternaria brassicicola on PDA containing Petri dish. We calculated inhibitory rate (%) in order to evaluate the antifungal efficacy of silver nanoparticles against pathogens. Treatment with 100ppm AgNPs resulted in maximum inhibition of Alternaria brassicicola i.e.92.2%. 110ppm of AgNPS also shows the same result, therefore 100ppm AgNPs was treated as optimize concentration. AgNPs effectively inhibited the growth of a Alternaria brassicicola, which suggests that AgNPs could be used as fungicide in plant disease management. Further research and development are necessary to translate this technology into plant disease management strategies.

  13. Synthesis and optical properties of silver nanoparticles in ORMOCER

    NASA Astrophysics Data System (ADS)

    Stepanov, Andrey L.; Kiyan, Roman; Ovsianikov, Alexander; Nuzhdin, Vladimir I.; Valeev, Valery F.; Osin, Yuri N.; Chichkov, Boris N.

    2012-08-01

    Experimental results on synthesis of metal nanoparticles in ORMOCER by ion implantation are presented. Silver ions were implanted into organic/inorganic matrix at an accelerating energy of 30 keV and doses in the range of 0.25ṡ1017 to 0.75ṡ1017 ion/cm2. The silver ions form metal nanoparticles, which demonstrate surface plasmon absorption at the wavelength of 425-580 nm. The nonlinear absorption of new composite materials is measured by Z-scan technique using 150 fs laser pulses at 780 nm wavelength. ORMOCER matrix shows two-photon nonlinear absorption, whereas ORMOCER with silver nanoparticles demonstrates saturated absorption. Some optical applications of these composite materials are discussed.

  14. Effects of dental porcelain containing silver nanoparticles on static fatigue.

    PubMed

    Fujieda, Tokushi; Uno, Mitsunori; Ishigami, Hajime; Kurachi, Masakazu; Kamemizu, Hideo; Wakamatsu, Nobukazu; Doi, Yutaka

    2013-01-01

    The purpose of this study was to clarify the effect of silver nanoparticles on the behavior of subcritical crack growth (SCG) in dental porcelains. Prior to occurrence of fast fracture in dental porcelains, SCG occurs and leads to strength degradation over time. SCG in dental porcelains can be characterized by the stress corrosion susceptibility coefficient, n. A higher n value means a higher resistance to SCG. In this study, porcelain disks were prepared by mixing a commercial dental porcelain powder with different concentrations of silver nanoparticles, and then air-dried and fired according to manufacturer's instructions. Stress corrosion susceptibility coefficients of powder compacts were determined using a post-indentation method. A Vickers indenter was applied to the porcelain surface, and lengths of median cracks were measured at fixed time intervals over a 24-h period to calculate n. Addition of silver nanoparticles significantly increased the stress corrosion susceptibility coefficient of dental porcelain.

  15. Antimicrobial Activities of Silver Nanoparticles Synthesized by Using Water Extract of Arnicae anthodium.

    PubMed

    Dobrucka, Renata; Długaszewska, Jolanta

    2015-06-01

    Green synthesis of nanoparticles has gained significant importance in recent years and has become the one of the most preferred methods. Also, green synthesis of nanoparticles is valuable branch of nanotechnology. Plant extracts are eco-friendly and can be an economic option for synthesis of nanoparticles. This study presents method the synthesis of silver nanoparticles using water extract of Arnicae anthodium. Formation of silver nanoparticles was confirmed by UV-visble spectroscopy, Fourier transform infrared spectroscopy and total reflection X-ray fluorescence analysis. The morphology of the synthesized silver nanoparticles was verified by SEM-EDS. The obtained silver nanoparticles were used to study their antimicrobial activity.

  16. Innovative method to avoid the reduction of silver ions to silver nanoparticles \\left( A{{g}^{+}}\\to Ag{}^\\circ \\right) in silver ion conducting based polymer electrolytes

    NASA Astrophysics Data System (ADS)

    Aziz, Shujahadeen B.; Abidin, Zul Hazrin Z.; Kadir, M. F. Z.

    2015-03-01

    In this research work an innovative method is used to prevent the silver ion reduction in solid polymer electrolytes. The x-ray diffraction (XRD) results reveal the disruption of the crystalline nature of chitosan (CS) and formation of silver nanoparticles upon addition of silver triflate (AgTf) salt. The UV-vis measurement confirms the existence of silver nanoparticles via the broad surface plasmon resonance (SPR) peak. Upon the addition of Al2O3 nanoparticles the SPR peak intensity is greatly reduced. The amorphous domain of the CS:silver triflate (CS:AgTf) system increases with the addition of Al2O3 nanoparticles up to 4 wt.%. Deconvolution of the XRD results reveals that a larger crystallite size is obtained for higher Al2O3 concentrations and the peaks due to silver nanoparticles almost disappear. Scanning electron microscope (SEM) analyses show that Al2O3 nanoparticles are well dispersed at low concentrations and the leakage of chains of silver nanoparticles to the membrane surface almost disappear. The XRD, UV-vis, SEM and energy-dispersive x-ray (EDX) results strongly support that the reduction of silver ions to silver nanoparticles (Ag+ → Ag°) in the CS:silver triflate system is significantly avoided upon the addition of an Al2O3 filler.

  17. Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold.

    PubMed

    Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

    2014-02-01

    The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials.

  18. Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System

    NASA Astrophysics Data System (ADS)

    Liu, J.; Burrow, E.; Hwang, Y.; Lenhart, J.

    2013-12-01

    Nanoparticles are increasingly being used in industrial processes and consumer products that exploit their beneficial properties and improve our daily lives. Nevertheless, they also attract attention when released into natural environment due to their potential for causing adverse effects. The fate and transport of nanoparticles in aqueous systems have been the focus of intense study. However, their interactions with other natural particles have received only limited attention. Clay minerals are ubiquitous in most aquatic systems and their variably charged surfaces can act as deposition sites that can alter the fate and transport of nanoparticles in natural aqueous environments. In this study, we investigated the homoaggregation of silver nanoparticles with different coating layers and their heteroaggregation behavior with clay minerals (illite, kaolinite, montmorillonite) in neutral pH solutions. Silver nanoparticles with a nominal diameter of 80 nm were synthesized with three different surface coating layers: uncoated, citrate-coated and Tween-coated. Illite (IMt-2), kaolinite (KGa-2), and montmorillonite (SWy-2) were purchased from the Clay Mineral Society (Indiana) and pretreated to obtain monocationic (Na-clay) and dicationic (Ca-clay) suspensions before the experiments. The change in hydrodynamic diameter as a function of time was monitored using dynamic light scattering (DLS) measurements in order to evaluate early stage aggregation as a function of electrolyte concentration in both the homo- and heteroaggregation scenarios. A shift in the critical coagulation concentration (CCC) values to lower electrolyte concentrations was observed in binary systems, compared to single silver nanoparticle and clay systems. The results also suggest more rapid aggregation in binary system during the early aggregation stage when compared to the single-particle systems. The behavior of citrate-coated silver nanoparticles was similar to that of the bare particles, while the

  19. The morphology of silver nanoparticles prepared by enzyme-induced reduction.

    PubMed

    Schneidewind, Henrik; Schüler, Thomas; Strelau, Katharina K; Weber, Karina; Cialla, Dana; Diegel, Marco; Mattheis, Roland; Berger, Andreas; Möller, Robert; Popp, Jürgen

    2012-01-01

    Silver nanoparticles were synthesized by an enzyme-induced growth process on solid substrates. In order to customize the enzymatically grown nanoparticles (EGNP) for analytical applications in biomolecular research, a detailed study was carried out concerning the time evolution of the formation of the silver nanoparticles, their morphology, and their chemical composition. Therefore, silver-nanoparticle films of different densities were investigated by using scanning as well as transmission electron microscopy to examine their structure. Cross sections of silver nanoparticles, prepared for analysis by transmission electron microscopy were additionally studied by energy-dispersive X-ray spectroscopy in order to probe their chemical composition. The surface coverage of substrates with silver nanoparticles and the maximum particle height were determined by Rutherford backscattering spectroscopy. Variations in the silver-nanoparticle films depending on the conditions during synthesis were observed. After an initial growth state the silver nanoparticles exhibit the so-called desert-rose or nanoflower-like structure. This complex nanoparticle structure is in clear contrast to the auto-catalytically grown spherical particles, which maintain their overall geometrical appearance while increasing their diameter. It is shown, that the desert-rose-like silver nanoparticles consist of single-crystalline plates of pure silver. The surface-enhanced Raman spectroscopic (SERS) activity of the EGNP structures is promising due to the exceptionally rough surface structure of the silver nanoparticles. SERS measurements of the vitamin riboflavin incubated on the silver nanoparticles are shown as an exemplary application for quantitative analysis.

  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. 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.

  2. Antimicrobial dependence of silver nanoparticles on surface plasmon resonance bands against Escherichia coli

    PubMed Central

    Mlalila, Nichrous G; Swai, Hulda Shaidi; Hilonga, Askwar; Kadam, Dattatreya M

    2017-01-01

    This study presents a simple and trouble-free method for determining the antimicrobial properties of silver nanoparticles (AgNPs) based on the surface plasmon resonance (SPR) bands. AgNPs were prepared by chemical reduction method using silver nitrates as a metallic precursor and formaldehyde (HCHO) as a reducing agent and capped by polyethylene glycol. Effects of several processing variables on the size and shape of AgNPs were monitored using an ultraviolet–visible spectrophotometer based on their SPR bands. The formed particles showing various particle shapes and full width at half maximum (FWHM) were tested against Escherichia coli by surface spreading using agar plates containing equal amounts of selected AgNPs samples. The NPs exhibited higher antimicrobial properties; however, monodispersed spherical NPs with narrow FWHM were more effective against E. coli growth. The NPs prepared are promising candidates in diverse applications such as antimicrobial agents in the food and biomedical industries. PMID:28053512

  3. Sensitive signal-on fluorescent sensing for copper ions based on the polyethyleneimine-capped silver nanoclusters-cysteine system.

    PubMed

    Zhang, Na; Qu, Fei; Luo, Hong Qun; Li, Nian Bing

    2013-08-12

    In this work, we present a label-free sensor for copper ions. This sensor is composed of silver nanoclusters and cysteine. The fluorescence of the silver nanoclusters was quenched by cysteine, which was recovered in the presence of copper ions. This binding of silver nanoclusters to cysteine promoted agglomeration of silver nanoclusters to yield larger non-fluorescent silver nanoparticles. The presence of copper ions resulted in the oxidation of cysteine to form a disulfide compound, leading to recovery of fluorescence of the silver nanoclusters. The fluorescence of the silver nanoclusters in the presence of cysteine increased with increasing concentration of copper ions in the range of 10-200 nM. The detection limit of this sensor for copper ions was 2.3 nM. The silver nanoclusters-cysteine sensor provides a simple, cost-effective, and sensitive platform for the detection of copper ions.

  4. Pulmonary Toxicity of Instilled Silver Nanoparticles: Influence of Size, Coating and Rat Strain

    PubMed Central

    Seiffert, Joanna; Hussain, Farhana; Wiegman, Coen; Li, Feng; Bey, Leo; Baker, Warren; Porter, Alexandra; Ryan, Mary P.; Chang, Yan; Gow, Andrew; Zhang, Junfeng; Zhu, Jie; Tetley, Terry D.; Chung, Kian Fan

    2015-01-01

    Particle size and surface chemistry are potential determinants of silver nanoparticle (AgNP) respiratory toxicity that may also depend on the lung inflammatory state. We compared the effects of intratracheally-administered AgNPs (20nm and 110nm; polyvinylpyrrolidone (PVP) and citrate-capped; 0.1 mg/Kg) in Brown-Norway (BN) and Sprague-Dawley (SD) rats. In BN rats, there was both a neutrophilic and eosinophilic response, while in SD rats, there was a neutrophilic response at day 1, greatest for the 20nm citrate-capped AgNPs. Eosinophilic cationic protein was increased in bronchoalveolar lavage (BAL) in BN and SD rats on day 1. BAL protein and malondialdehyde levels were increased in BN rats at 1 and 7 days, and BAL KC, CCL11 and IL-13 levels at day 1, with increased expression of CCL11 in lung tissue. Pulmonary resistance increased and compliance decreased at day 1, with persistence at day 7. The 20nm, but not the 110 nm, AgNPs increased bronchial hyperresponsiveness on day 1, which continued at day 7 for the citrate-capped AgNPs only. The 20nm versus the 110 nm size were more proinflammatory in terms of neutrophil influx, but there was little difference between the citrate-capped versus the PVP-capped AgNPs. AgNPs can induce pulmonary eosinophilic and neutrophilic inflammation with bronchial hyperresponsiveness, features characteristic of asthma. PMID:25747867

  5. Pulmonary toxicity of instilled silver nanoparticles: influence of size, coating and rat strain.

    PubMed

    Seiffert, Joanna; Hussain, Farhana; Wiegman, Coen; Li, Feng; Bey, Leo; Baker, Warren; Porter, Alexandra; Ryan, Mary P; Chang, Yan; Gow, Andrew; Zhang, Junfeng; Zhu, Jie; Tetley, Terry D; Chung, Kian Fan

    2015-01-01

    Particle size and surface chemistry are potential determinants of silver nanoparticle (AgNP) respiratory toxicity that may also depend on the lung inflammatory state. We compared the effects of intratracheally-administered AgNPs (20 nm and 110 nm; polyvinylpyrrolidone (PVP) and citrate-capped; 0.1 mg/Kg) in Brown-Norway (BN) and Sprague-Dawley (SD) rats. In BN rats, there was both a neutrophilic and eosinophilic response, while in SD rats, there was a neutrophilic response at day 1, greatest for the 20 nm citrate-capped AgNPs. Eosinophilic cationic protein was increased in bronchoalveolar lavage (BAL) in BN and SD rats on day 1. BAL protein and malondialdehyde levels were increased in BN rats at 1 and 7 days, and BAL KC, CCL11 and IL-13 levels at day 1, with increased expression of CCL11 in lung tissue. Pulmonary resistance increased and compliance decreased at day 1, with persistence at day 7. The 20 nm, but not the 110 nm, AgNPs increased bronchial hyperresponsiveness on day 1, which continued at day 7 for the citrate-capped AgNPs only. The 20 nm versus the 110 nm size were more proinflammatory in terms of neutrophil influx, but there was little difference between the citrate-capped versus the PVP-capped AgNPs. AgNPs can induce pulmonary eosinophilic and neutrophilic inflammation with bronchial hyperresponsiveness, features characteristic of asthma.

  6. Morphology-controlled synthesis of silver nanoparticles on the silicon substrate by a facile silver mirror reaction

    NASA Astrophysics Data System (ADS)

    Jiang, Bing; Li, Meicheng; Bai, Fan; Yu, Hang; Mwenya, Trevor; Li, Yingfeng; Song, Dandan

    2013-03-01

    The Ag nanoparticles (Ag-NPs) with different morphology were quickly deposited on p-type Si substrate by a facile silver mirror reaction without capping agents and morphology driving seeds at room temperature. By controlling the concentrations of [Ag(NH3)2]+ and reducing agent (glucose), short rod and quasi-round Ag-NPs were produced on Si substrate. The results show that the shape of the Ag-NPs was defined by [Ag(NH3)2]+ concentration. The concentration of glucose affected the coverage fraction instead of shape of Ag-NPs. Under the high concentrations of [Ag(NH3)2]+, anisotropic crystal structure of short rod Ag-NPs were ascribed to total energy minimization. The high glucose concentration led to agglomeration of particles. Different nanoporous structures on Si substrate etched by using Ag-NPs enable control over its properties and are useful for the solar cells applications.

  7. Silver Nanoparticles as Real Topical Bullets for Wound Healing

    PubMed Central

    Gunasekaran, Thirumurugan; Nigusse, Tadele; Dhanaraju, Magharla Dasaratha

    2012-01-01

    Nanotechnology is on the threshold of providing a host of new materials and approaches, revolutionizing the medical and pharmaceutical fields. Several areas of medical care are already profiting from the advantage that nanotechnology offers. Recently, silver nanoparticles are attracting interest for a clinical application because of its potential biological properties such as antibacterial activity, anti-inflammatory effects, and wound healing efficacy, which could be exploited in developing better dressings for wounds and ulcers. This article reviews the role of silver nanoparticles in wound healing. PMID:24527370

  8. Addition of platinum and silver nanoparticles to toughen dental porcelain.

    PubMed

    Fujieda, Tokushi; Uno, Mitsunori; Ishigami, Hajime; Kurachi, Masakazu; Wakamatsu, Nobukazu; Doi, Yutaka

    2012-01-01

    Several studies have investigated toughening porcelain that is layered over a frame or a core. The introduction of residual compressive stress to the surface of porcelain has been shown to be effective to strengthen it. In the present study, nanoparticles of precious metals of silver and platinum (rather than non-precious metals) were used to evaluate if they could increase the fracture resistance of porcelain. The addition of silver and platinum nanoparticles was found to improve the mechanical properties of porcelain since it increased both the Young's modulus and the fracture toughness of commercial porcelain.

  9. Biosynthesis of silver and gold nanoparticles using Bacillus licheniformis.

    PubMed

    Sriram, Muthu Irulappan; Kalishwaralal, Kalimuthu; Gurunathan, Sangiliyandi

    2012-01-01

    Owing to the wide-ranging applications of noble metal nanoparticles in diverse areas of science and technology, different methods have been proposed for their synthesis. Here, we describe the methods for the intracellular biosynthesis of silver and gold nanoparticles using the bacterium Bacillus licheniformis KK2 and this same procedure can be followed for other bacteria as well. The biological synthesis of nanoparticles is highly eco-friendly and possesses distinct advantages such as enhanced stability, better control over the size, shape, and monodispersity of the nanoparticles, when compared with the more traditional physical and chemical methods which often involves the use of hazardous chemicals creating environmental concern.

  10. Comparison of the toxicity of silver, gold and platinum nanoparticles in developing zebrafish embryos.

    PubMed

    Asharani, P V; Lianwu, Yi; Gong, Zhiyuan; Valiyaveettil, Suresh

    2011-03-01

    Nanoparticles have diverse applications in electronics, medical devices, therapeutic agents and cosmetics. While the commercialization of nanoparticles is rapidly expanding, their health and environmental impact is not well understood. Toxicity assays of silver, gold, and platinum nanoparticles, using zebrafish embryos to study their developmental effects were carried out. Gold (Au-NP, 15-35 nm), silver (Ag-NP, 5-35 nm) and platinum nanoparticles (Pt-NP, 3-10 nm) were synthesized using polyvinyl alcohol (PVA) as a capping agent. Toxicity was recorded in terms of mortality, hatching delay, phenotypic defects and metal accumulation. The addition of Ag-NP resulted in a concentration-dependant increase in mortality rate. Both Ag-NP and Pt-NP induced hatching delays, as well as a concentration dependant drop in heart rate, touch response and axis curvatures. Ag-NP also induced other significant phenotypic changes including pericardial effusion, abnormal cardiac morphology, circulatory defects and absence or malformation of the eyes. In contrast, Au-NP did not show any indication of toxicity. Uptake and accumulation of nanoparticles in embryos was confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES), which revealed detectable levels in embryos within 72 hpf. Ag-NP and Au-NP were taken up by the embryos in relatively equal amounts whereas lower Pt concentrations were observed in embryos exposed to Pt-NP. This was probably due to the small size of the Pt nanoparticles compared to Ag-NP and Au-NP, thus resulting in fewer metal atoms being retained in the embryos. Among the nanoparticles studied, Ag-NPs were found to be the most toxic and Au-NPs the non-toxic. The toxic effects exhibited by the zebrafish embryos as a consequence of nanoparticle exposure, accompanied by the accumulation of metals inside the body calls for urgent further investigations in this field.

  11. Interaction between Silver Nanoparticles and Spinach Leaf

    NASA Astrophysics Data System (ADS)

    Tian, Y.; Li, H.; Zhang, Y.; Riser, E.; He, S.; Zhang, W.

    2013-12-01

    Interactions of engineered nanoparticles (ENPs) with plant surfaces are critical to assessing the bioavailability of ENPs to edible plants and to further evaluating impacts of ENPs on ecological health and food safety. Silver nanoparticles (i.e., nanoAg) could enter the agroecosystems either as an active ingredient in pesticides or from other industrial and consumer applications. Thus, in the events of pesticide application, rainfall, and irrigation, vegetable leaves could become in contact and then interact with nanoAg. The present study was to assess whether the interaction of nanoAg with spinach leaves can be described by classical sorption models and to what extent it depends on and varies with dispersion methods, environmental temperature, and ion release. We investigated the stability and ion release of nanoAg dispersed by sodium dodecyl sulfate (SDS, 1%) and humic acid (HA, 10 mg C/L) solutions, as well as sorption and desorption of nanoAg on and from the fresh spinach leaf. Results showed SDS-nanoAg released about 2%-8% more Ag ion than HA-nanoAg. The sorption of Ag ion, described by the Freundlich model in the initial concentration range of 0.6-50 mg/L, was 2-4 times higher than that of nanoAg. The sorption of nanoAg on spinach leaf can be fitted by the Langmuir model, and the maximum sorption amount of HA-nanoAg and SDS-nanoAg was 0.21 and 0.41 mg/g, respectively. The higher sorption of SDS-nanoAg relative to that of HA-nanoAg could be partially resulted from the higher release of Ag ion from the former. The maximum desorption amount of HA-nanoAg and SDS-nanoAg in 1% SDS solution was 0.08 and 0.10 mg/g, respectively. NanoAg attachment on and its penetration to the spinach leaf was visualized by the Scanning Electron Microscope equipped with an Energy Dispersive Spectrometer (SEM-EDS). It is equally important that the less sorption of nanoAg under low environmental temperature could be partially due to the closure of stomata, as verified by SEM-EDS. Cyto

  12. Eco-friendly approach for nanoparticles synthesis and mechanism behind antibacterial activity of silver and anticancer activity of gold nanoparticles.

    PubMed

    Patil, Maheshkumar Prakash; Kim, Gun-Do

    2017-01-01

    This review covers general information about the eco-friendly process for the synthesis of silver nanoparticles (AgNP) and gold nanoparticles (AuNP) and focuses on mechanism of the antibacterial activity of AgNPs and the anticancer activity of AuNPs. Biomolecules in the plant extract are involved in reduction of metal ions to nanoparticle in a one-step and eco-friendly synthesis process. Natural plant extracts contain wide range of metabolites including carbohydrates, alkaloids, terpenoids, phenolic compounds, and enzymes. A variety of plant species and plant parts have been successfully extracted and utilized for AgNP and AuNP syntheses. Green-synthesized nanoparticles eliminate the need for a stabilizing and capping agent and show shape and size-dependent biological activities. Here, we describe some of the plant extracts involved in nanoparticle synthesis, characterization methods, and biological applications. Nanoparticles are important in the field of pharmaceuticals for their strong antibacterial and anticancer activity. Considering the importance and uniqueness of this concept, the synthesis, characterization, and application of AgNPs and AuNPs are discussed in this review.

  13. Direct synthesis of silver nanoparticles in ionic liquid

    NASA Astrophysics Data System (ADS)

    Corrêa, Cíntia M.; Bizeto, Marcos A.; Camilo, Fernanda F.

    2016-05-01

    Ionic liquids have structural organization at nanoscale that can trigger the spontaneous ordering of structures in nanoscopic range. Due to this characteristic, several metal nanoparticles have been prepared in this media. In this paper, we describe the direct preparation of silver nanoparticles in the following imidazolium ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and in citrate tetrabutylammonium, that is an ionic liquid that acts as solvent and reducing agent at the same time. We also evaluated the morphology of the nanoparticles and the stability of the dispersions. Spherical silver nanoparticles with surface Plasmon bands in the range of 400-430 nm were produced in all the ionic liquids, with the only exception for the 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide that produced a black precipitate. The best results were obtained by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and citrate tetrabutylammonium ionic liquids. The former resulted in concentrated spherical silver nanoparticles dispersion (ca. 1.0 mM of Ag) with diameters ranging from 6 to 12 nm and by adding polyvinylpyrrolidone (PVP) to the dispersions they became stable for at least 1 month. The citrate tetrabutylammonium ionic liquid produced even more concentrated dispersion of spherical silver nanoparticles with diameters ranging from 2 to 6 nm. These dispersions were quite stable without the need of PVP, since the Plasmon band in the electronic absorption spectra remained unaltered for months after the preparation. The citrate tetrabutylammonium ionic liquid offers a slow kinetic for the silver nanoparticle formation as the citrate is a milder reducing agent than borohydride.

  14. Biocompatible capped iron oxide nanoparticles for Vibrio cholerae detection

    NASA Astrophysics Data System (ADS)

    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 (Fe3O4)) 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 Fe3O4 and CA-Fe3O4/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 Fe3O4, CA-Fe3O4 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 (Fe3O4) and 189.51 nm (CA-Fe3O4) by DLS measurement. The results of electrochemical response studies of the fabricated BSA/Ab/CA-Fe2O3/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 Ω/ng ml-1 cm-2, and reproducibility more than 11 times.

  15. Cytocompatible antifungal acrylic resin containing silver nanoparticles for dentures

    PubMed Central

    Acosta-Torres, Laura Susana; Mendieta, Irasema; Nuñez-Anita, Rosa Elvira; Cajero-Juárez, Marcos; Castaño, Víctor M

    2012-01-01

    Background Inhibition of Candida albicans on denture resins could play a significant role in preventing the development of denture stomatitis. The safety of a new dental material with antifungal properties was analyzed in this work. Methods Poly(methyl methacrylate) [PMMA] discs and PMMA-silver nanoparticle discs were formulated, with the commercial acrylic resin, Nature-CrylTM, used as a control. Silver nanoparticles were synthesized and characterized by ultraviolet-visible spectroscopy, dispersive Raman spectroscopy, and transmission electron microscopy. The antifungal effect was assessed using a luminescent microbial cell viability assay. Biocompatibility tests were carried out using NIH-3T3 mouse embryonic fibroblasts and a Jurkat human lymphocyte cell line. Cells were cultured for 24 or 72 hours in the presence or absence of the polymer formulations and analyzed using three different tests, ie, cellular viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell proliferation by enzyme-linked immunosorbent assay BrdU, and genomic DNA damage (Comet assay). Finally, the samples were evaluated mechanically, and the polymer-bearing silver nanoparticles were analyzed microscopically to evaluate dispersion of the nanoparticles. Results The results show that PMMA-silver nanoparticle discs significantly reduce adherence of C. albicans and do not affect metabolism or proliferation. They also appear not to cause genotoxic damage to cells. Conclusion The present work has developed a new biocompatible antifungal PMMA denture base material. PMID:22969297

  16. 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.

  17. Uncovering loss mechanisms in silver nanoparticle-blended plasmonic organic solar cells.

    PubMed

    Wu, Bo; Wu, Xiangyang; Guan, Cao; Fai Tai, Kong; Yeow, Edwin Kok Lee; Jin Fan, Hong; Mathews, Nripan; Sum, Tze Chien

    2013-01-01

    There has been much controversy over the incorporation of organic-ligand-encapsulated plasmonic nanoparticles in the active layer of bulk heterojunction organic solar cells, where both enhancement and detraction in performance have been reported. Here through comprehensive transient optical spectroscopy and electrical characterization, we demonstrate evidence of traps responsible for performance degradation in plasmonic organic solar cells fabricated with oleylamine-capped silver nanoparticles blended in the poly (3-hexylthiophene):[6,6]-phenyl-C 61-butyric acid methyl ester active layer. Despite an initial increase in exciton generation promoted by the presence of silver nanoparticles, transient absorption spectroscopy reveals no increase in the later free polaron population-attributed to fast trapping of polarons by nearby nanoparticles. The increased trap-assisted recombination is also reconfirmed by light intensity-dependent electrical measurements. These new insights into the photophysics and charge dynamics of plasmonic organic solar cells would resolve the existing controversy and provide clear guidelines for device design and fabrication.

  18. Uncovering loss mechanisms in silver nanoparticle-blended plasmonic organic solar cells

    NASA Astrophysics Data System (ADS)

    Wu, Bo; Wu, Xiangyang; Guan, Cao; Fai Tai, Kong; Yeow, Edwin Kok Lee; Jin Fan, Hong; Mathews, Nripan; Sum, Tze Chien

    2013-06-01

    There has been much controversy over the incorporation of organic-ligand-encapsulated plasmonic nanoparticles in the active layer of bulk heterojunction organic solar cells, where both enhancement and detraction in performance have been reported. Here through comprehensive transient optical spectroscopy and electrical characterization, we demonstrate evidence of traps responsible for performance degradation in plasmonic organic solar cells fabricated with oleylamine-capped silver nanoparticles blended in the poly (3-hexylthiophene):[6,6]-phenyl-C 61-butyric acid methyl ester active layer. Despite an initial increase in exciton generation promoted by the presence of silver nanoparticles, transient absorption spectroscopy reveals no increase in the later free polaron population—attributed to fast trapping of polarons by nearby nanoparticles. The increased trap-assisted recombination is also reconfirmed by light intensity-dependent electrical measurements. These new insights into the photophysics and charge dynamics of plasmonic organic solar cells would resolve the existing controversy and provide clear guidelines for device design and fabrication.

  19. Green synthesis, characterization and biological activities of silver nanoparticles from alkalinized Cymbopogon citratus Stapf

    NASA Astrophysics Data System (ADS)

    Ajayi, Emmanuel; Afolayan, Anthony

    2017-03-01

    Silver nanoparticles (AgNPs) have been synthesized from the alkalinized leaf extract of Cymbopogon citratus, also known as lemon grass (LG), and characterized for their size and shape using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The total formation of the AgNPs was observed visually with a color change from yellow to brownish-black. Fourier transform infrared spectroscopy (FTIR) and energy dispersive x-ray spectroscopy (EDS/EDX) were conducted to determine the various functional groups and the concentration of metal ions in the nanoparticles. The data analysis showed spherically shaped nanoparticles with a size of 10–33 nm, as revealed by TEM, thereby complementing the result for SEM. FTIR identifies the ethylene group as a reducing and capping agent for the formation of the nanoparticles. The x-ray diffraction pattern confirmed the presence of silver crystallites as well as their size, further confirming the result of the TEM. AgNPs do not exhibit very good potential as free radical scavengers when compared to the standards. The synthesized AgNPs in suspension showed activity against both gram-positive and gram-negative bacteria, with minimum inhibitory concentrations (MICs) in the range of 31.25–62.5 µg ml‑1. In summary, the synthesized AgNPs possessed an acceptable size and shape.

  20. 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

  1. Modeling molecular effects on plasmon transport: Silver nanoparticles with tartrazine

    NASA Astrophysics Data System (ADS)

    Arntsen, Christopher; Lopata, Kenneth; Wall, Michael R.; Bartell, Lizette; Neuhauser, Daniel

    2011-02-01

    Modulation of plasmon transport between silver nanoparticles by a yellow fluorophore, tartrazine, is studied theoretically. The system is studied by combining a finite-difference time-domain Maxwell treatment of the electric field and the plasmons with a time-dependent parameterized method number 3 simulation of the tartrazine, resulting in an effective Maxwell/Schrödinger (i.e., classical/quantum) method. The modeled system has three linearly arranged small silver nanoparticles with a radius of 2 nm and a center-to-center separation of 4 nm; the molecule is centered between the second and third nanoparticles. We initiate an x-polarized current on the first nanoparticle and monitor the transmission through the system. The molecule rotates much of the x-polarized current into the y-direction and greatly reduces the overall transmission of x-polarized current.

  2. Modeling molecular effects on plasmon transport: silver nanoparticles with tartrazine.

    PubMed

    Arntsen, Christopher; Lopata, Kenneth; Wall, Michael R; Bartell, Lizette; Neuhauser, Daniel

    2011-02-28

    Modulation of plasmon transport between silver nanoparticles by a yellow fluorophore, tartrazine, is studied theoretically. The system is studied by combining a finite-difference time-domain Maxwell treatment of the electric field and the plasmons with a time-dependent parameterized method number 3 simulation of the tartrazine, resulting in an effective Maxwell∕Schrödinger (i.e., classical∕quantum) method. The modeled system has three linearly arranged small silver nanoparticles with a radius of 2 nm and a center-to-center separation of 4 nm; the molecule is centered between the second and third nanoparticles. We initiate an x-polarized current on the first nanoparticle and monitor the transmission through the system. The molecule rotates much of the x-polarized current into the y-direction and greatly reduces the overall transmission of x-polarized current.

  3. Polyol mediated hexadecylamine capped silver allied nanobimetallic particles and their fluxional properties

    NASA Astrophysics Data System (ADS)

    Adekoya, J. A.; Dare, E. O.; Mesubi, M. A.; Revaprasadu, N.

    2015-11-01

    The syntheses of hexadecylamine seed mediated Ag/M (M=Co, Ni, Pd and Pt) allied nanobimetallic particles were successfully carried out by the successive reduction of ligand capped metal ions with polyols, resulting in concomitant precipitation of some high index faceted hybrid Ag/M bimetal nanoparticles. The optical measurements revealed the existence of surface plasmon band and peak broadening that causes diffusion processes of the metal sols to decrease making it possible to monitor the changes spectrophotometrically. The bimetallic nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and electron microscopy techniques which confirm the formation of alloyed clusters.

  4. 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.

  5. Plant-Mediated Synthesis of Silver Nanoparticles and Their Stabilization by Wet Stirred Media Milling

    NASA Astrophysics Data System (ADS)

    Baláž, Matej; Balážová, Ľudmila; Daneu, Nina; Dutková, Erika; Balážová, Miriama; Bujňáková, Zdenka; Shpotyuk, Yaroslav

    2017-02-01

    Within this study, a stable nanosuspension of silver nanoparticles (Ag NPs) was prepared using a two-step synthesis and stabilization approach. The Ag NPs were synthesized from a silver nitrate solution using the Origanum vulgare L. plant extract as the reducing agent. The formation of nanoparticles was finished upon 15 min, and subsequently, stabilization by polyvinylpyrrolidone (PVP) using wet stirred media milling was applied. UV-Vis spectra have shown a maximum at 445 nm, corresponding to the formation of spherical Ag NPs. Infrared spectroscopy was used to examine the interaction between Ag NPs and the capping agents. TEM study has shown the formation of Ag NPs with two different average sizes (38 ± 10 nm and 7 ± 3 nm) after the plant-mediated synthesis, both randomly distributed within the organic matrix. During milling in PVP, the clusters of Ag NPs were destroyed, the Ag NPs were fractionized and embedded in PVP. The nanosuspensions of PVP-capped Ag NPs were stable for more than 26 weeks, whereas for the non-stabilized nanosuspensions, only short-term stability for about 1 week was documented.

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

    PubMed

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

    2014-07-15

    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.

  7. 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.

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

    PubMed Central

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

    2015-01-01

    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

  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. Extraordinarily high conductivity of flexible adhesive films by hybrids of silver nanoparticle-nanowires

    NASA Astrophysics Data System (ADS)

    Muhammed Ajmal, C.; Mol Menamparambath, Mini; Ryeol Choi, Hyouk; Baik, Seunghyun

    2016-06-01

    Highly conductive flexible adhesive (CFA) film was developed using micro-sized silver flakes (primary fillers), hybrids of silver nanoparticle-nanowires (secondary fillers) and nitrile butadiene rubber. The hybrids of silver nanoparticle-nanowires were synthesized by decorating silver nanowires with silver nanoparticle clusters using bifunctional cysteamine as a linker. The dispersion in ethanol was excellent for several months. Silver nanowires constructed electrical networks between the micro-scale silver flakes. The low-temperature surface sintering of silver nanoparticles enabled effective joining of silver nanowires to silver flakes. The hybrids of silver nanoparticle-nanowires provided a greater maximum conductivity (54 390 S cm-1) than pure silver nanowires, pure multiwalled carbon nanotubes, and multiwalled carbon nanotubes decorated with silver nanoparticles in nitrile butadiene rubber matrix. The resistance change was smallest upon bending when the hybrids of silver nanoparticle-nanowires were employed. The adhesion of the film on polyethylene terephthalate substrate was excellent. Light emitting diodes were successfully wired to the CFA circuit patterned by the screen printing method for application demonstration.

  11. Extraordinarily high conductivity of flexible adhesive films by hybrids of silver nanoparticle-nanowires.

    PubMed

    Ajmal, C Muhammed; Menamparambath, Mini Mol; Choi, Hyouk Ryeol; Baik, Seunghyun

    2016-06-03

    Highly conductive flexible adhesive (CFA) film was developed using micro-sized silver flakes (primary fillers), hybrids of silver nanoparticle-nanowires (secondary fillers) and nitrile butadiene rubber. The hybrids of silver nanoparticle-nanowires were synthesized by decorating silver nanowires with silver nanoparticle clusters using bifunctional cysteamine as a linker. The dispersion in ethanol was excellent for several months. Silver nanowires constructed electrical networks between the micro-scale silver flakes. The low-temperature surface sintering of silver nanoparticles enabled effective joining of silver nanowires to silver flakes. The hybrids of silver nanoparticle-nanowires provided a greater maximum conductivity (54 390 S cm(-1)) than pure silver nanowires, pure multiwalled carbon nanotubes, and multiwalled carbon nanotubes decorated with silver nanoparticles in nitrile butadiene rubber matrix. The resistance change was smallest upon bending when the hybrids of silver nanoparticle-nanowires were employed. The adhesion of the film on polyethylene terephthalate substrate was excellent. Light emitting diodes were successfully wired to the CFA circuit patterned by the screen printing method for application demonstration.

  12. Antibacterial efficacy of silver nanoparticles against Escherichia coli

    NASA Astrophysics Data System (ADS)

    Pattabi, Rani M.; Thilipan, G. Arun Kumar; Bhat, Vinayachandra; Sridhar, K. R.; Pattabi, Manjunatha

    2013-02-01

    Silver nanoparticles (AgNPs) synthesized by subjecting an aqueous solution of AgNO3 and polyvinyl alcohol to irradiation from an UV lamp has been studied for its antibacterial potential against Gram-negative bacteria (Escherichia coli). The diameter of the zone of inhibition is found to depend on both the irradiation time and the nanoparticle concentration. As the synthesis method adopted uses no toxic reagents, these particles may serve as promising candidates in the search for better antibacterial agents.

  13. 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

  14. Extracellular biosynthesis of silver nanoparticles using Rhizopus stolonifer.

    PubMed

    AbdelRahim, Khalid; Mahmoud, Sabry Younis; Ali, Ahmed Mohamed; Almaary, Khalid Salmeen; Mustafa, Abd El-Zaher M A; Husseiny, Sherif Moussa

    2017-01-01

    Synthesis of silver nanoparticles (AgNPs) has become a necessary field of applied science. Biological method for synthesis of AgNPs by Rhizopus stolonifer aqueous mycelial extract was used. The AgNPs were identified by UV-visible spectrometry, X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectrometry (FT-IR). The presence of surface plasmon band around 420 nm indicates AgNPs formation. The characteristic of the AgNPs within the face-centered cubic (fcc) structure are indicated by the peaks of the X-ray diffraction (XRD) pattern corresponding to (1 1 1), (2 0 0) and (2 2 0) planes. Spherical, mono-dispersed and stable AgNPs with diameter around 9.47 nm were prepared and affirmed by high-resolution transmission electron microscopy (HR-TEM). Fourier Transform Infrared (FTIR) shows peaks at 1426 and 1684 cm(-1) that affirm the presence of coat covering protein the AgNPs which is known as capping proteins. Parameter optimization showed the smallest size of AgNPs (2.86 ± 0.3 nm) was obtained with 10(-2) M AgNO3 at 40 °C. The present study provides the proof that the molecules within aqueous mycelial extract of R. stolonifer facilitate synthesis of AgNPs and highlight on value-added from R. stolonifer for cost effectiveness. Also, eco-friendly medical and nanotechnology-based industries could also be provided. Size of prepared AgNPs could be controlled by temperature and AgNO3 concentration. Further studies are required to study effect of more parameters on size and morphology of AgNPs as this will help in the control of large scale production of biogenic AgNPs.

  15. Selective growth and integration of silver nanoparticles on silver nanowires at room conditions for transparent nano-network electrode.

    PubMed

    Lu, Haifei; Zhang, Di; Ren, Xingang; Liu, Jian; Choy, Wallace C H

    2014-10-28

    Recently, metal nanowires have received great research interests due to their potential as next-generation flexible transparent electrodes. While great efforts have been devoted to develop enabling nanowire electrodes, reduced contact resistance of the metal nanowires and improved electrical stability under continuous bias operation are key issues for practical applications. Here, we propose and demonstrate an approach through a low-cost, robust, room temperature and room atmosphere process to fabricate a conductive silver nano-network comprising silver nanowires and silver nanoparticles. To be more specific, silver nanoparticles are selectively grown and chemically integrated in situ at the junction where silver nanowires meet. The site-selective growth of silver nanoparticles is achieved by a plasmon-induced chemical reaction using a simple light source at very low optical power density. Compared to silver nanowire electrodes without chemical treatment, we observe tremendous conductivity improvement in our silver nano-networks, while the loss in optical transmission is negligible. Furthermore, the silver nano-networks exhibit superior electrical stability under continuous bias operation compared to silver nanowire electrodes formed by thermal annealing. Interestingly, our silver nano-network is readily peeled off in water, which can be easily transferred to other substrates and devices for versatile applications. We demonstrate the feasibly transferrable silver conductive nano-network as the top electrode in organic solar cells. Consequently, the transparent and conductive silver nano-networks formed by our approach would be an excellent candidate for various applications in optoelectronics and electronics.

  16. Radiochemical synthesis of 105gAg-labelled silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Ichedef, C.; Simonelli, F.; Holzwarth, U.; Bagaria, J. Piella; Puntes, V. F.; Cotogno, G.; Gilliland, D.; Gibson, N.

    2013-11-01

    A method for synthesis of radiolabelled silver nanoparticles is reported. The method is based on proton activation of silver metal powder, enriched in 107Ag, with a 30.7 MeV proton beam. At this proton energy 105gAg is efficiently created, mainly via the 107Ag(p,3n)105Cd → 105gAg reaction. 105gAg has a half-life of 41.29 days and emits easily detectable gamma radiation on decay to 105Pd. This makes it very useful as a tracing radionuclide for experiments over several weeks or months. Following activation and a period to allow short-lived radionuclides to decay, the powder was dissolved in concentrated nitric acid in order to form silver nitrate (AgNO3), which was used to synthesise radiolabelled silver nanoparticles via the process of sodium borohydride reduction. For comparison, non-radioactive silver nanoparticles were synthesised using commercially supplied AgNO3 in order to check if the use of irradiated Ag powder as a starting material would alter in any way the final nanoparticle characteristics. Both nanoparticle types were characterised using dynamic light scattering, zeta-potential and X-ray diffraction measurements, while additionally the non-radioactive samples were analysed by transmission electron microscopy and UV-Vis spectrometry. A hydrodynamic diameter of about 16 nm was determined for both radiolabelled and non-radioactive nanoparticles, while the electron microscopy on the non-radioactive samples indicated that the physical size of the metal NPs was (7.3 ± 1.4) nm.

  17. Adsorption mechanisms of RNA mononucleotides on silver nanoparticles.

    PubMed

    Miljanić, Snežana; Dijanošić, Adriana; Matić, 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.

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

    NASA Astrophysics Data System (ADS)

    Singaravelan, R.; Bangaru Sudarsan Alwar, S.

    2015-11-01

    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.

  19. Interaction of Silver Nanoparticles with Serum Proteins Affects Their Antimicrobial Activity In Vivo

    PubMed Central

    Gnanadhas, Divya Prakash; Ben Thomas, Midhun; Thomas, Rony; Raichur, Ashok M.

    2013-01-01

    The emergence of multidrug-resistant bacteria is a global threat for human society. There exist recorded data that silver was used as an antimicrobial agent by the ancient Greeks and Romans during the 8th century. Silver nanoparticles (AgNPs) are of potential interest because of their effective antibacterial and antiviral activities, with minimal cytotoxic effects on the cells. However, very few reports have shown the usage of AgNPs for antibacterial therapy in vivo. In this study, we deciphered the importance of the chosen methods for synthesis and capping of AgNPs for their improved activity in vivo. The interaction of AgNPs with serum albumin has a significant effect on their antibacterial activity. It was observed that uncapped AgNPs exhibited no antibacterial activity in the presence of serum proteins, due to the interaction with bovine serum albumin (BSA), which was confirmed by UV-Vis spectroscopy. However, capped AgNPs [with citrate or poly(vinylpyrrolidone)] exhibited antibacterial properties due to minimized interactions with serum proteins. The damage in the bacterial membrane was assessed by flow cytometry, which also showed that only capped AgNPs exhibited antibacterial properties, even in the presence of BSA. In order to understand the in vivo relevance of the antibacterial activities of different AgNPs, a murine salmonellosis model was used. It was conclusively proved that AgNPs capped with citrate or PVP exhibited significant antibacterial activities in vivo against Salmonella infection compared to uncapped AgNPs. These results clearly demonstrate the importance of capping agents and the synthesis method for AgNPs in their use as antimicrobial agents for therapeutic purposes. PMID:23877702

  20. Mycosynthesis of silver nanoparticles using extract of endophytic fungi, Penicillium species of Glycosmis mauritiana, and its antioxidant, antimicrobial, anti-inflammatory and tyrokinase inhibitory activity

    NASA Astrophysics Data System (ADS)

    Govindappa, M.; Farheen, H.; Chandrappa, C. P.; Channabasava; Rai, Ravishankar V.; Raghavendra, Vinay B.

    2016-09-01

    Silver nanoparticles were synthesized using endophytic fungal species, Penicillium species from Glycosmis mautitiana. Phytochemicals, namely tannins, saponins, terpenoids and flavonoids, were identified in Penicillium species extracts, and act as agents of reducing and capping in the conversion of silver nanoparticles into nanoparticles. Using SEM, UV-spectroscopy and XRD, the Penicillium species silver nanoparticles (PsAgNPs) were characterized. The PsAgNPs are shown to be strong antioxidants (DDPH and FRAP), have demonstrated anti-inflammatory properties by three different methods in vitro and strongly inhibited the activity of xanthine oxidase, lipoxygenase and tyrosine kinase. E. coli and P. aeruginosa bacterial species were strongly inhibited by PsAgNPs activity at maximum levels and SEM picture of P. aeruginosa confirms these effects and that they were shrunken due to the toxic effect of PsAgNPs.

  1. Oxidative dissolution of silver nanoparticles: A new theoretical approach.

    PubMed

    Adamczyk, Zbigniew; Oćwieja, Magdalena; Mrowiec, Halina; Walas, Stanisław; Lupa, Dawid

    2016-05-01

    A general model of an oxidative dissolution of silver particle suspensions was developed that rigorously considers the bulk and surface solute transport. A two-step surface reaction scheme was proposed that comprises the formation of the silver oxide phase by direct oxidation and the acidic dissolution of this phase leading to silver ion release. By considering this, a complete set of equations is formulated describing oxygen and silver ion transport to and from particles' surfaces. These equations are solved in some limiting cases of nanoparticle dissolution in dilute suspensions. The obtained kinetic equations were used for the interpretation of experimental data pertinent to the dissolution kinetics of citrate-stabilized silver nanoparticles. In these kinetic measurements the role of pH and bulk suspension concentration was quantitatively evaluated by using the atomic absorption spectrometry (AAS). It was shown that the theoretical model adequately reflects the main features of the experimental results, especially the significant increase in the dissolution rate for lower pH. Also the presence of two kinetic regimes was quantitatively explained in terms of the decrease in the coverage of the fast dissolving oxide layer. The overall silver dissolution rate constants characterizing these two regimes were determined.

  2. Silver colloid nanoparticles: synthesis, characterization, and their antibacterial activity.

    PubMed

    Panacek, Ales; Kvítek, Libor; Prucek, Robert; Kolar, Milan; Vecerova, Renata; Pizúrova, Nadezda; Sharma, Virender K; Nevecna, Tat'jana; Zboril, Radek

    2006-08-24

    A one-step simple synthesis of silver colloid nanoparticles with controllable sizes is presented. In this synthesis, reduction of [Ag(NH(3))(2)](+) complex cation by four saccharides was performed. Four saccharides were used: two monosaccharides (glucose and galactose) and two disaccharides (maltose and lactose). The syntheses performed at various ammonia concentrations (0.005-0.20 mol L(-1)) and pH conditions (11.5-13.0) produced a wide range of particle sizes (25-450 nm) with narrow size distributions, especially at the lowest ammonia concentrations. The average size, size distribution, morphology, and structure of particles were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and UV/Visible absorption spectrophotometry. The influence of the saccharide structure (monosacharides versus disaccharides) on the size of silver particles is briefly discussed. The reduction of [Ag(NH(3))(2)](+) by maltose produced silver particles with a narrow size distribution with an average size of 25 nm, which showed high antimicrobial and bactericidal activity against Gram-positive and Gram-negative bacteria, including highly multiresistant strains such as methicillin-resistant Staphylococcus aureus. Antibacterial activity of silver nanoparticles was found to be dependent on the size of silver particles. A very low concentration of silver (as low as 1.69 mug/mL Ag) gave antibacterial performance.

  3. 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...

  4. In Vivo Toxicity of Silver Nanoparticles and Silver Ions in Zebrafish (Danio rerio)

    PubMed Central

    Bilberg, Katrine; Hovgaard, Mads Bruun; Besenbacher, Flemming; Baatrup, Erik

    2012-01-01

    The influence of water chemistry on characterised polyvinyl pyrrolidone- (PVP-) coated silver nanoparticles (81 nm) was investigated. NaCl solution series of 100–800 mg L−1 lead to initial and temporal increase in nanoparticles size, but agglomeration was limited. pH variation (5–8) had only minor influence on the hydrodynamic particle size. Acute toxicity of nanosivler to zebrafish (Danio rerio) was investigated in a 48-hour static renewal study and compared with the toxicity of silver ions (AgNO3). The nanosilver and silver ion 48-hour median lethal concentration (LC50) values were 84 μg L−1 and 25 μg L−1, respectively. To investigate exposure-related stress, the fish behaviour was observed visually after 0, 3, 6, 12, 24, 27, 30, and 48 hours of both nanosilver and ionic silver treatments. These observations revealed increased rate of operculum movement and surface respiration after nanosilver exposure, suggesting respiratory toxicity. The present study demonstrates that silver nanoparticles are lethal to zebrafish. PMID:22174711

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

    PubMed

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

    2014-12-01

    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.

  6. 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

  7. Quenching of chlorophyll fluorescence induced by silver nanoparticles.

    PubMed

    Queiroz, A M; Mezacasa, A V; Graciano, D E; Falco, W F; M'Peko, J-C; Guimarães, F E G; Lawson, T; Colbeck, I; Oliveira, S L; Caires, A R L

    2016-11-05

    The interaction between chlorophyll (Chl) and silver nanoparticles (AgNPs) was evaluated by analyzing the optical behavior of Chl molecules surrounded by different concentrations of AgNPs (10, 60, and 100nm of diameter). UV-Vis absorption, steady state and time-resolved fluorescence measurements were performed for Chl in the presence and absence of these nanoparticles. AgNPs strongly suppressed the Chl fluorescence intensity at 678nm. The Stern-Volmer constant (KSV) showed that fluorescence suppression is driven by the dynamic quenching process. In particular, KSV was nanoparticle size-dependent with an exponential decrease as a function of the nanoparticle diameter. Finally, changes in the Chl fluorescence lifetime in the presence of nanoparticles demonstrated that the fluorescence quenching may be induced by the excited electron transfer from the Chl molecules to the metal nanoparticles.

  8. Quenching of chlorophyll fluorescence induced by silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Queiroz, A. M.; Mezacasa, A. V.; Graciano, D. E.; Falco, W. F.; M'Peko, J.-C.; Guimarães, F. E. G.; Lawson, T.; Colbeck, I.; Oliveira, S. L.; Caires, A. R. L.

    2016-11-01

    The interaction between chlorophyll (Chl) and silver nanoparticles (AgNPs) was evaluated by analyzing the optical behavior of Chl molecules surrounded by different concentrations of AgNPs (10, 60, and 100 nm of diameter). UV-Vis absorption, steady state and time-resolved fluorescence measurements were performed for Chl in the presence and absence of these nanoparticles. AgNPs strongly suppressed the Chl fluorescence intensity at 678 nm. The Stern-Volmer constant (KSV) showed that fluorescence suppression is driven by the dynamic quenching process. In particular, KSV was nanoparticle size-dependent with an exponential decrease as a function of the nanoparticle diameter. Finally, changes in the Chl fluorescence lifetime in the presence of nanoparticles demonstrated that the fluorescence quenching may be induced by the excited electron transfer from the Chl molecules to the metal nanoparticles.

  9. Characterization of silver nanoparticles synthesized on titanium dioxide fine particles

    NASA Astrophysics Data System (ADS)

    Niño-Martínez, N.; Martínez-Castañón, G. A.; Aragón-Piña, A.; Martínez-Gutierrez, F.; Martínez-Mendoza, J. R.; Ruiz, Facundo

    2008-02-01

    Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO2 particles using a simple aqueous reduction method. The reducing agent used was NaBH4; different molar ratios TiO2:Ag were also used. The nanocomposites thus prepared were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), dynamic light scattering (DLS) and UV-visible (UV-vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopy studies (TEM and STEM) we observed that the silver nanoparticles are homogeneously distributed over the surface of TiO2 particles and that the TiO2:Ag molar ratio plays an important role. We used three different TiO2Ag molar ratios and the size of the silver nanoparticles is 10, 20 and 80 nm, respectively. It was found that the antibacterial activity of the nanocomposites increases considerably comparing with separated silver nanoparticles and TiO2 particles.

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

    PubMed

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

    2011-07-01

    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%.

  11. 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…

  12. Silver nanoparticles: Large scale solvothermal synthesis and optical properties

    SciTech Connect

    Wani, Irshad A.; Khatoon, Sarvari; Ganguly, Aparna; Ahmed, Jahangeer; Ganguli, Ashok K.; Ahmad, Tokeer

    2010-08-15

    Silver nanoparticles have been successfully synthesized by a simple and modified solvothermal method at large scale using ethanol as the refluxing solvent and NaBH{sub 4} as reducing agent. The nanopowder was investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), UV-visible and BET surface area studies. XRD studies reveal the monophasic nature of these highly crystalline silver nanoparticles. Transmission electron microscopic studies show the monodisperse and highly uniform nanoparticles of silver of the particle size of 5 nm, however, the size is found to be 7 nm using dynamic light scattering which is in good agreement with the TEM and X-ray line broadening studies. The surface area was found to be 34.5 m{sup 2}/g. UV-visible studies show the absorption band at {approx}425 nm due to surface plasmon resonance. The percentage yield of silver nanoparticles was found to be as high as 98.5%.

  13. 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%.

  14. Silver nanoparticles and electroporation: Their combinational effect on Leishmania major.

    PubMed

    Dolat, Elham; Rajabi, Omid; Salarabadi, Samaneh Soudmand; Yadegari-Dehkordi, Sajedeh; Sazgarnia, Ameneh

    2015-12-01

    Leishmaniasis is an emerging and uncontrolled disease. The use of routine drugs has been limited due to proven side effects and drug resistance. Interestingly, novel approaches such as nanotechnology have been applied as a therapeutic modality. Silver nanoparticles have shown antileishmanial effects but because of their nonspecific and toxic effects on normal cells, their use has been limited. On the other hand, it has been demonstrated that electric pulses induce electropores on cell membranes resulting in higher entrance of certain molecules into cells. There is a hypothesis proposing that use of electroporation and silver nanoparticles simultaneously can induce greater accumulation of particles in infected cells, besides higher toxicity. In this study, after applying electric pulses with different concentrations of silver nanoparticles (SNPs), cell survival rate was determined by standard viability assays. On the basis of these data, 2 μg/ml of SNPs and 700 V/cm with 100 μs duration of electroporation were selected as the non-lethal condition. Promastigotes and infected macrophage cells received both treatments and the survival percentage and Infection Index were calculated. In parasites and cells receiving both treatments, higher toxicity was observed in comparison to each treatment given individually, showing a synergic effect on promastigotes. Therefore, application of electric pulses could overcome limitations in using the antileishmanial properties of silver nanoparticles.

  15. 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.

  16. 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...

  17. Silver nanoparticles are broad-spectrum bactericidal and virucidal compounds

    PubMed Central

    2011-01-01

    The advance in nanotechnology has enabled us to utilize particles in the size of the nanoscale. This has created new therapeutic horizons, and in the case of silver, the currently available data only reveals the surface of the potential benefits and the wide range of applications. Interactions between viral biomolecules and silver nanoparticles suggest that the use of nanosystems may contribute importantly for the enhancement of current prevention of infection and antiviral therapies. Recently, it has been suggested that silver nanoparticles (AgNPs) bind with external membrane of lipid enveloped virus to prevent the infection. Nevertheless, the interaction of AgNPs with viruses is a largely unexplored field. AgNPs has been studied particularly on HIV where it was demonstrated the mechanism of antiviral action of the nanoparticles as well as the inhibition the transmission of HIV-1 infection in human cervix organ culture. This review discusses recent advances in the understanding of the biocidal mechanisms of action of silver Nanoparticles. PMID:21812950

  18. Characterization of silver nanoparticles synthesized on titanium dioxide fine particles.

    PubMed

    Niño-Martínez, N; Martínez-Castañón, G A; Aragón-Piña, A; Martínez-Gutierrez, F; Martínez-Mendoza, J R; Ruiz, Facundo

    2008-02-13

    Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO(2) particles using a simple aqueous reduction method. The reducing agent used was NaBH(4); different molar ratios TiO(2):Ag were also used. The nanocomposites thus prepared were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), dynamic light scattering (DLS) and UV-visible (UV-vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopy studies (TEM and STEM) we observed that the silver nanoparticles are homogeneously distributed over the surface of TiO(2) particles and that the TiO(2):Ag molar ratio plays an important role. We used three different TiO(2)Ag molar ratios and the size of the silver nanoparticles is 10, 20 and 80 nm, respectively. It was found that the antibacterial activity of the nanocomposites increases considerably comparing with separated silver nanoparticles and TiO(2) particles.

  19. Hydrophilic silver nanoparticles with tunable optical properties: application for the detection of heavy metals in water

    PubMed Central

    Mochi, Federico; Ciotta, Erica; Casalboni, Mauro; De Matteis, Fabio; Fontana, Laura; Testa, Giovanna; Fratoddi, Ilaria

    2016-01-01

    Due their excellent chemo-physical properties and ability to exhibit surface plasmon resonance, silver nanoparticles (AgNPs) have become a material of choice in various applications, such as nanosensors, electronic devices, nanobiotechnology and nanomedicine. In particular, from the environmental monitoring perspective, sensors based on silver nanoparticles are in great demand because of their antibacterial and inexpensive synthetic method. In the present study, we synthesized AgNPs in water phase using silver nitrate as precursor molecules, hydrophilic thiol (3-mercapto-1-propanesulfonic acid sodium salt, 3MPS) and sodium borohydride as capping and reducing agents, respectively. The AgNPs were characterized using techniques such as surface plasmon resonance (SPR) spectroscopy, dynamic light scattering (DLS), zeta potential (ζ-potential) measurements and scanning tunneling microscopy (STM). Further, to demonstrate the environmental application of our AgNPs, we also applied them for heavy metal sensing by detecting visible color modification due to SPR spectral changes. We found that these negatively charged AgNPs show good response to nickel (II) and presented good sensibility properties for the detection of low amount of ions in water in the working range of 1.0–0.1 ppm. PMID:28144514

  20. Hydrophilic silver nanoparticles with tunable optical properties: application for the detection of heavy metals in water.

    PubMed

    Prosposito, Paolo; Mochi, Federico; Ciotta, Erica; Casalboni, Mauro; De Matteis, Fabio; Venditti, Iole; Fontana, Laura; Testa, Giovanna; Fratoddi, Ilaria

    2016-01-01

    Due their excellent chemo-physical properties and ability to exhibit surface plasmon resonance, silver nanoparticles (AgNPs) have become a material of choice in various applications, such as nanosensors, electronic devices, nanobiotechnology and nanomedicine. In particular, from the environmental monitoring perspective, sensors based on silver nanoparticles are in great demand because of their antibacterial and inexpensive synthetic method. In the present study, we synthesized AgNPs in water phase using silver nitrate as precursor molecules, hydrophilic thiol (3-mercapto-1-propanesulfonic acid sodium salt, 3MPS) and sodium borohydride as capping and reducing agents, respectively. The AgNPs were characterized using techniques such as surface plasmon resonance (SPR) spectroscopy, dynamic light scattering (DLS), zeta potential (ζ-potential) measurements and scanning tunneling microscopy (STM). Further, to demonstrate the environmental application of our AgNPs, we also applied them for heavy metal sensing by detecting visible color modification due to SPR spectral changes. We found that these negatively charged AgNPs show good response to nickel (II) and presented good sensibility properties for the detection of low amount of ions in water in the working range of 1.0-0.1 ppm.

  1. Efficient synthesis and structural characterization of silver nanoparticle/ bis(o-phenolpropyl)silicone composites.

    PubMed

    Kim, Myoung-Hee; Woo, Hee-Gweon; Lee, Byeong-Gweon; Kim, Do-Heyoung; Yang, Kap-Seung; Kim, Bo-Hye; Park, Yeong-Joon; Ko, Young Chun; Roh, Sung-Hee; Sohn, Honglae

    2011-02-01

    Silver nanoparticle/bis(o-phenolpropyl)silicone composites have been synthesized by the reduction of silver nitrate with bis(o-phenolpropyl)silicone BPPS [(o-phenolpropyl)2(SiMe2O)n, n = 2, 3, 8, 236]. TEM and FE-SEM data clearly show that the silver nanoparticles with the size of < 20 nm are well dispersed throughout the BPPS matrix in the composites. XRD patterns are consistent with those for multicrystalline silver. The size of silver nanoparticles increased with increasing the relative molar concentration of silver salts added. It was found that in the absence of BPPS, most of the silver nanoparticles undergo macroscopic precipitation by agglomeration, indicating that BPPS is essential to stabilize the silver nanoparticles.

  2. Studies on the antimicrobial properties of colloidal silver nanoparticles stabilized by bovine serum albumin.

    PubMed

    Mathew, Thomas V; Kuriakose, Sunny

    2013-01-01

    Colloidal silver nanoparticles were synthesised using sol-gel method and these nanoparticles were stabilised by encapsulated into the scaffolds of bovine serum albumin. Silver nanoparticles and encapsulated products were characterised by FTIR, NMR, XRD, TG, SEM and TEM analyses. Silver nanoparticle encapsulated bovine serum albumin showed highly potent antibacterial activity towards the bacterial strains such as Staphylococcus aureus, Serratia marcescens, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae.

  3. Hybrid Antimicrobial Enzyme and Silver Nanoparticle Coatings for Medical Instruments (Postprint)

    DTIC Science & Technology

    2009-01-01

    within coatings. EXPERIMENTAL SECTION Reagents and the Synthesis of Silver Nanoparticles. Hen egg white lysozyme (∼95%, ∼50 000 units per mg of protein...solution but without prior formation of nanoparticles. For the first two control experiments, lysozyme and silver nanoparticles were used in separate ...coatings on medical devices that combine the bacteriolytic activity of lysozyme and the biocidal properties of silver nanoparticles. Colloidal

  4. Silver nanoparticles cause complications in pregnant mice

    PubMed Central

    Zhang, Xi-Feng; Park, Jung-Hyun; Choi, Yun-Jung; Kang, Min-Hee; Gurunathan, Sangiliyandi; Kim, Jin-Hoi

    2015-01-01

    Background Silver nanoparticles (AgNPs) have attracted much interest and have been used for antibacterial, antifungal, anticancer, and antiangiogenic applications because of their unique properties. The increased usage of AgNPs leads to a potential hazard to human health. However, the potential effects of AgNPs on animal models are not clear. This study was designed to investigate the potential impact of AgNPs on pregnant mice. Methods The synthesis of AgNPs was performed using culture extracts of Bacillus cereus. The synthesized AgNPs were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. AgNPs were administrated into pregnant mice via intravenous infusion at 1.0 mg/kg doses at 6.5 days postcoitum (dpc). At 13.5, 15.5, and 17.5 dpc, the pregnant mice were euthanized, and the embryo and placenta were isolated. The meiotic status of oocytes was evaluated. DNA methylation studies were performed, and aberrant imprinting disrupted fetal, placental, and postnatal development. Quantitative real-time polymerase chain reaction analysis and Western blot were used to analyze various gene expressions. Results The synthesized AgNPs were uniformly distributed and were spherical in shape with an average size of 8 nm. AgNPs exposure increased the meiotic progression of female germ cells in the fetal mouse ovaries, and maternal AgNP exposure significantly disrupted imprinted gene expression in 15.5 dpc embryos and placentas, such as Ascl2, Snrpn, Kcnq1ot1, Peg3, Zac1, H19, Igf2r, and Igf2; DNA methylation studies revealed that AgNPs exposure significantly altered the methylation levels of differentially methylated regions of Zac1. Conclusion The results from this study indicated that early exposure to AgNPs has the potential to disrupt fetal and postnatal health through epigenetic changes in the embryo and abnormal development of the placenta. These results can contribute to research involved in the safe use of

  5. 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.

  6. Facile, one-pot synthesis, and antibacterial activity of mesoporous silica nanoparticles decorated with well-dispersed silver nanoparticles.

    PubMed

    Tian, Yue; Qi, Juanjuan; Zhang, Wei; Cai, Qiang; Jiang, Xingyu

    2014-08-13

    In this study, we exploit a facile, one-pot method to prepare MCM-41 type mesoporous silica nanoparticles decorated with silver nanoparticles (Ag-MSNs). Silver nanoparticles with diameter of 2-10 nm are highly dispersed in the framework of mesoporous silica nanoparticles. These Ag-MSNs possess an enhanced antibacterial effect against both Gram-positive and Gram-negative bacteria by preventing the aggregation of silver nanoparticles and continuously releasing silver ions for one month. The cytotoxicity assay indicates that the effective antibacterial concentration of Ag-MSNs shows little effect on human cells. This report describes an efficient and economical route to synthesize mesoporous silica nanoparticles with uniform silver nanoparticles, and these nanoparticles show promising applications as antibiotics.

  7. Plant mediated green synthesis and antibacterial activity of silver nanoparticles using Emblica officinalis fruit extract

    NASA Astrophysics Data System (ADS)

    Ramesh, P. S.; Kokila, T.; Geetha, D.

    2015-05-01

    A green straight forward method of synthesizing silver nanoparticles (AgNPs) in an aqueous medium was designed using Emblica officinalis (EO) fruit extract as stabilizer and reducer. The formation of AgNPs depends on the effect of extract concentration and pH were studied. The AgNPs was synthesized using E.officinalis (fruit extract) and nanoparticles were characterized using UV-Vis spectrophotometer, the presence of biomolecules of E.officinalis capped in AgNPs was found by FT-IR analysis, shape and size were examined by SEM and XRD. The XRD analysis respects the Bragg's law and confirmed the crystalline nature of silver nanoparticles. From XRD the average size of AgNPs was found to be around 15 nm. AFM has proved to be very helpful in the determination and verification of various morphological features and parameters. EO fruit extract mediated AgNPs was synthesized and confirmed through kinetic behavior of nanoparticles. The shape of the bio-synthesized AgNPs was spherical. Potent biomolecules of E.officinalis such as polyphenols, glucose, and fructose was capped with AgNPs which reduces the toxicity. The synthesized AgNPs were tested for its antibacterial activity against the isolates by disc diffusion method. The obtained results confirmed that the E.officinalis fruit extract is a very good bioreductant for the synthesis of AgNPs. It was investigated that the synthesized AgNPs showed inhibition and had significant antibacterial against both gram-positive and gram-negative bacterial strains.

  8. Plant mediated green synthesis and antibacterial activity of silver nanoparticles using Emblica officinalis fruit extract.

    PubMed

    Ramesh, P S; Kokila, T; Geetha, D

    2015-05-05

    A green straight forward method of synthesizing silver nanoparticles (AgNPs) in an aqueous medium was designed using Emblica officinalis (EO) fruit extract as stabilizer and reducer. The formation of AgNPs depends on the effect of extract concentration and pH were studied. The AgNPs was synthesized using E.officinalis (fruit extract) and nanoparticles were characterized using UV-Vis spectrophotometer, the presence of biomolecules of E.officinalis capped in AgNPs was found by FT-IR analysis, shape and size were examined by SEM and XRD. The XRD analysis respects the Bragg's law and confirmed the crystalline nature of silver nanoparticles. From XRD the average size of AgNPs was found to be around 15nm. AFM has proved to be very helpful in the determination and verification of various morphological features and parameters. EO fruit extract mediated AgNPs was synthesized and confirmed through kinetic behavior of nanoparticles. The shape of the bio-synthesized AgNPs was spherical. Potent biomolecules of E.officinalis such as polyphenols, glucose, and fructose was capped with AgNPs which reduces the toxicity. The synthesized AgNPs were tested for its antibacterial activity against the isolates by disc diffusion method. The obtained results confirmed that the E.officinalis fruit extract is a very good bioreductant for the synthesis of AgNPs. It was investigated that the synthesized AgNPs showed inhibition and had significant antibacterial against both gram-positive and gram-negative bacterial strains.

  9. Development of antimicrobial water filtration hybrid material from bio source calcium carbonate and silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Apalangya, Vitus; Rangari, Vijaya; Tiimob, Boniface; Jeelani, Shaik; Samuel, Temesgen

    2014-03-01

    Biobased calcium carbonate and silver hybrid nanoparticles were synthesized using a simple mechanochemical milling technique. The XRD spectrum showed that the hybrid materials is composed of crystalline calcite and silver nanoparticles. The TEM results indicated that the silver nanoparticles are discrete, uncapped and well stabilized in the surface of the eggshell derived calcium carbonate particles. The silver nanoparticles are spherical in shape and 5-20 nm in size. The SEM studies indicated that the eggshells are in micron size with the silver nanoparticle embedded in their surface. The hybrid eggshell/silver nanocomposite exhibited superior inhibition of E. coli growth using the Kirby-Bauer discs diffusion assay and comparing the zone of inhibition around the filter paper disc impregnated with the hybrid particles against pristine silver nanoparticles.

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

    PubMed

    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.

  11. 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

  12. Antibacterial properties of novel poly(methyl methacrylate) nanofiber containing silver nanoparticles.

    PubMed

    Kong, Hyeyoung; Jang, Jyongsik

    2008-03-04

    Poly(methyl methacrylate) (PMMA) nanofiber containing silver nanoparticles was synthesized by radical-mediated dispersion polymerization and applied to an antibacterial agent. UV-vis spectroscopic analysis indicated that the silver nanoparticles were continually released from the polymer nanofiber in aqueous solution. The antibacterial properties of silver/PMMA nanofiber against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria were evaluated using minimum inhibitory concentration (MIC), the modified Kirby-Bauer method, and a kinetic test. The MIC test demonstrated that the silver/PMMA nanofiber had enhanced antimicrobial efficacy compared to that of silver sulfadiazine and silver nitrate at the same silver concentration.

  13. Synthesis of silver nanoparticles and the optical properties

    NASA Astrophysics Data System (ADS)

    Yang, Ai-ling; Zhang, Zhen-zhen; Yang, Yun; Bao, Xi-chang; Yang, Ren-qiang

    2013-01-01

    Silver nanoparticles (NPs) of 5-15 nm are synthesized with the reduction of silver nitrate (AgNO3) by formaldehyde (HCHO) and using polyethylenemine (PEI) as a stabilizer. Transmission electron microscopy (TEM) analysis shows the size of the Ag NPs increases with the increase of HCHO contents. The absorption and emission peaks of the original colloids are red shifted with increasing the size of Ag NPs. The absorption and emission peaks are at 344 nm, 349 nm, 357 nm, 362 nm, 364 nm and 444 nm, 458 nm, 519 nm, 534 nm, 550 nm, respectively. The fluorescence intensities of the silver colloids increase with increasing the NPs size (or the contents of HCHO). With the diluted fold increasing, the fluorescence intensity of the diluted silver colloids increases firstly then decreases. Compared with that of the original silver colloids, the emission peaks are blue shifted. For the diluted silver colloids, when the fluorescence intensity is maximum, the emission peaks are all near 444 nm. The 16-fold diluted silver colloid gets to the maximum emission intensity when the mole ratio of AgNO3 and HCHO is 1:6.

  14. Bacterial growth on a superhydrophobic surface containing silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Heinonen, S.; Nikkanen, J.-P.; Laakso, J.; Raulio, M.; Priha, O.; Levänen, E.

    2013-12-01

    The antibacterial effect of silver can be exploited in the food and beverage industry and medicinal applications to reduce biofouling of surfaces. Very small amount of silver ions are enough to destructively affect the metabolism of bacteria. Moreover, superhydrophobic properties could reduce bacterial adhesion to the surface. In this study we fabricated superhydrophobic surfaces that contained nanosized silver particles. The superhydrophobic surfaces were manufactured onto stainless steel as combination of ceramic nanotopography and hydrophobication by fluorosilane. Silver nanoparticles were precipitated onto the surface by a chemical method. The dissolution of silver from the surface was tested in an aqueous environment under pH values of 1, 3, 5, 7, 9, 11 and 13. The pH value was adjusted with nitric acid and ammonia. It was found that dissolution rate of silver increased as the pH of the solution altered from the pH of de-ionized water to lower and higher pH values but dissolution occurred also in de-ionized water. The antimicrobial potential of this coating was investigated using bacterial strains isolated from the brewery equipment surfaces. The results showed that the number of bacteria adhering onto steel surface was significantly reduced (88%) on the superhydrophobic silver containing coating.

  15. 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.

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

    PubMed Central

    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

  17. 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.

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

    SciTech Connect

    Thappily, Praveen E-mail: shiiuvenus@gmail.com; Shiju, K. E-mail: shiiuvenus@gmail.com

    2014-10-15

    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.

  19. 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.

  20. Comparison of in vitro toxicity of silver ions and silver nanoparticles on human hepatoma cells.

    PubMed

    Vrček, Ivana Vinković; Žuntar, Irena; Petlevski, Roberta; Pavičić, Ivan; Dutour Sikirić, Maja; Ćurlin, Marija; Goessler, Walter

    2016-06-01

    Scientific information on the potential harmful effects of silver nanoparticles (AgNPs) on human health severely lags behind their exponentially growing applications in consumer products. In assessing the toxic risk of AgNP usage, liver, as a detoxifying organ, is particularly important. The aim of this study was to explore the toxicity mechanisms of nano and ionic forms of silver on human hepatoblastoma (HepG2) cells. The results showed that silver ions and citrate-coated AgNPs reduced cell viability in a dose-dependent manner. The IC50 values of silver ions and citrate-coated AgNPs were 0.5 and 50 mg L(-1) , respectively. The LDH leakage and inhibition of albumin synthesis, along with decreased ALT activity, indicated that treatment with either AgNP or Ag ions resulted in membrane damage and reduced the cell function of human liver cells. Evaluation of oxidative stress markers demonstrating depletion of GSH, increased ROS production, and increased SOD activity, indicated that oxidative stress might contribute to the toxicity effects of nano and ionic forms of silver. The observed toxic effect of AgNP on HepG2 cells was substantially weaker than that caused by ionic silver, while the uptake of nano and ionic forms of silver by HepG2 cells was nearly the same. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 679-692, 2016.

  1. A physiologically based pharmacokinetic model for ionic silver and silver nanoparticles

    PubMed Central

    Bachler, Gerald; von Goetz, Natalie; Hungerbühler, Konrad

    2013-01-01

    Silver is a strong antibiotic that is increasingly incorporated into consumer products as a bulk, salt, or nanosilver, thus potentially causing side-effects related to human exposure. However, the fate and behavior of (nano)silver in the human body is presently not well understood. In order to aggregate the existing experimental information, a physiologically based pharmacokinetic model (PBPK) was developed in this study for ionic silver and nanosilver. The structure of the model was established on the basis of toxicokinetic data from intravenous studies. The number of calibrated parameters was minimized in order to enhance the predictive capability of the model. We validated the model structure for both silver forms by reproducing exposure conditions (dermal, oral, and inhalation) of in vivo experiments and comparing simulated and experimentally assessed organ concentrations. Therefore, the percutaneous, intestinal, or pulmonary absorption fraction was estimated based on the blood silver concentration of the respective experimental data set. In all of the cases examined, the model could successfully predict the biodistribution of ionic silver and 15–150 nm silver nanoparticles, which were not coated with substances designed to prolong the circulatory time (eg, polyethylene glycol). Furthermore, the results of our model indicate that: (1) within the application domain of our model, the particle size and coating had a minor influence on the biodistribution; (2) in vivo, it is more likely that silver nanoparticles are directly stored as insoluble salt particles than dissolve into Ag+; and (3) compartments of the mononuclear phagocytic system play a minor role in exposure levels that are relevant for human consumers. We also give an example of how the model can be used in exposure and risk assessments based on five different exposure scenarios, namely dietary intake, use of three separate consumer products, and occupational exposure. PMID:24039420

  2. Presence of nanoparticles in wash water from conventional silver and nano-silver textiles.

    PubMed

    Mitrano, Denise M; Rimmele, Elisa; Wichser, Adrian; Erni, Rolf; Height, Murray; Nowack, Bernd

    2014-07-22

    Questions about how to regulate nanoenhanced products regularly arise as researchers determine possible nanoparticle transformation(s). Focusing concern on the incorporation and subsequent release of nano-Ag in fabrics often overshadows the fact that many "conventional silver" antimicrobials such as ionic silver, AgCl, metallic Ag, and other forms will also form different species of silver. In this study we used a laboratory washing machine to simulate the household laundering of a number of textiles prepared with known conventional Ag or nano-Ag treatments and a commercially available fabric incorporating yarns coated with bulk metallic Ag. Serial filtration allowed for quantification of total Ag released in various size fractions (>0.45 μm, < 0.45 μm, <0.1 μm, and <10 kDa), while characterization of particles with TEM/EDX provided insight on Ag transformation mechanisms. Most conventional Ag additives yielded more total Ag and more nanoparticulate-sized Ag in the washing liquid than fabrics that used nano-Ag treatments. Incorporating nano-silver into the fiber (as opposed to surface treatments) yielded less total Ag during fabric washing. A variety of metallic Ag, AgCl, and Ag/S particles were observed in washing solution by TEM/EDX to various extents depending on the initial Ag speciation in the fabrics. Very similar particles were also observed when dissolved ionic Ag was added directly into the washing liquid. On the basis of the present study, we can state that all silver-treated textiles, regardless of whether the treatment is "conventional" or "nano", can be a source of silver nanoparticles in washing solution when laundering fabrics. Indeed, in this study we observed that textiles treated with "conventional" silver have equal or greater propensity to form nano-silver particles during washing conditions than those treated with "nano"-silver. This fact needs to be strongly considered when addressing the risks of nano-silver and emphasizes that regulatory

  3. Functionalization of textiles with silver and zinc oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Pulit-Prociak, Jolanta; Chwastowski, Jarosław; Kucharski, Arkadiusz; Banach, Marcin

    2016-11-01

    The paper presents a method for functionalization of textile materials using fabric dyes modified with silver or zinc oxide nanoparticles. Embedding of these nanoparticles into the structure of other materials makes that the final product is characterized by antimicrobial properties. Indigo and commercially available dye were involved in studies. It is worth to note that silver nanoparticles were obtained in-situ in the reaction of preparing indigo dye and in the process of preparing commercial dye baths. Such a method allows reducing technological steps. The modified dyes were used for dyeing of cotton fibers. The antimicrobial properties of final textile materials were studied. Saccharomyces cerevisiae strain was used in microbiological test. The results confirmed biocidal activity of prepared materials.

  4. Optical absorption properties of dispersed gold and silver alloy nanoparticles.

    PubMed

    Wilcoxon, Jess

    2009-03-05

    The oldest topic in nanoscience is the size-dependent optical properties of gold and silver colloids or nanoparticles, first investigated scientifically by Michael Faraday in 1857. In the modern era, advances in both synthesis and characterization have resulted in new insights into the size-dependent absorbance of Au and Ag nanoparticles with sizes below the classical limit for Mie theory. In this paper we discuss the synthesis and properties of core/shell and nanoalloy particles of Au and Ag, compare them to particles of pure gold and silver, and discuss how alloying affects nanoparticle chemical stability. We show that composition, size, and nanostructure (e.g., core/shell vs quasi-random nanoalloy) can all be employed to adjust the optical absorbance properties. The type of nanostructure--core/shell vs alloy--is reflected in their optical absorbance features.

  5. Sampling for silver nanoparticles in aqueous media using a rotating disk electrode: evidence for selective sampling of silver nanoparticles in the presence of ionic silver.

    PubMed

    Steinberg, Spencer; Hodge, Vernon; Schumacher, Brian; Sovocool, Wayne

    2017-03-01

    Amendment of a carbon paste electrode consisting of graphite and Nujol®, with a variety of organic and inorganic materials, allows direct adsorption of silver nanoparticles (AgNPs) from aqueous solution in either open or close circuit modes. The adsorbed AgNPs are detected by stripping voltammetry. Detection limits of less than 1 ppb Ag are achievable with a rotating disk system. More than one silver peak was apparent in many of the stripping voltammograms. The appearance of multiple peaks could be due to different species of silver formed upon stripping or variation in the state of aggregation or size of nanoparticles. With most of these packing materials, dissolved Ag(+) was also extracted from aqueous solution, but, with a packing material made with Fe(II,III) oxide nanoparticles, only AgNPs were extracted. Therefore, it is the best candidate for determination of metallic AgNPs in aqueous environmental samples without interference from Ag(+).

  6. Bioinspired synthesis of highly stabilized silver nanoparticles using Ocimum tenuiflorum leaf extract and their antibacterial activity

    NASA Astrophysics Data System (ADS)

    Patil, Rupali S.; Kokate, Mangesh R.; Kolekar, Sanjay S.

    2012-06-01

    Biosynthesis of nanoparticles is under exploration due to wide biomedical applications and research interest in nanotechnology. We herein reports bioinspired synthesis of silver nanoparticles with the aid of novel, non toxic ecofriendly biological material namely Ocimum tenuiflorum leaf extract. It acts as reducing as well as stabilizing agent. An intense surface plasmon resonance band at ˜450 nm in the UV-visible spectrum clearly reveals the formation of silver nanoparticles. The photoluminescence spectrum was recorded to study excitation and emission. TEM and PSD by dynamic light scattering studies showed that size of silver nanoparticles to be in range 25-40 nm. Face centered cubic structure of silver nanoparticles are confirmed by SAED pattern. The charge on synthesized silver nanoparticles was determined by zeta potential. The colloidal solution of silver nanoparticles were found to exhibit high antibacterial activity against three different strains of bacteria Escherichia coli (Gram negative), Corney bacterium (gram positive), Bacillus substilus (spore forming).

  7. Bioinspired synthesis of highly stabilized silver nanoparticles using Ocimum tenuiflorum leaf extract and their antibacterial activity.

    PubMed

    Patil, Rupali S; Kokate, Mangesh R; Kolekar, Sanjay S

    2012-06-01

    Biosynthesis of nanoparticles is under exploration due to wide biomedical applications and research interest in nanotechnology. We herein reports bioinspired synthesis of silver nanoparticles with the aid of novel, non toxic ecofriendly biological material namely Ocimum tenuiflorum leaf extract. It acts as reducing as well as stabilizing agent. An intense surface plasmon resonance band at ∼450 nm in the UV-visible spectrum clearly reveals the formation of silver nanoparticles. The photoluminescence spectrum was recorded to study excitation and emission. TEM and PSD by dynamic light scattering studies showed that size of silver nanoparticles to be in range 25-40 nm. Face centered cubic structure of silver nanoparticles are confirmed by SAED pattern. The charge on synthesized silver nanoparticles was determined by zeta potential. The colloidal solution of silver nanoparticles were found to exhibit high antibacterial activity against three different strains of bacteria Escherichia coli (Gram negative), Corney bacterium (gram positive), Bacillus substilus (spore forming).

  8. Inhibitory effects of silver nanoparticles against adenovirus type 3 in vitro.

    PubMed

    Chen, Nana; Zheng, Yang; Yin, Jianjian; Li, Xiujing; Zheng, Conglong

    2013-11-01

    Adenoviruses are associated with respiratory, ocular, or gastrointestinal disease. With various species and high morbidity, adenoviruses are increasingly recognized as significant viral pathogen among pediatric and immunocompromised patients. However, there is almost no specific drug for treatment. Silver nanoparticles are demonstrated to be virucidal against influenza A (H1N1) virus, human immunodeficiency virus and Hepatitis B virus. Currently, there is no data regarding whether the silver nanoparticles inhibit the adenovirus or not. The aim of this study is to investigate the effect of silver nanoparticles on adenovirus type 3 (Ad3). The results revealed that HeLa cells infected with silver nanoparticles treated Ad3 did not show obvious CPE. The viability of HeLa cells infected with silver nanoparticles treated Ad3 was significantly higher than that of cells infected with untreated Ad3. There was a significant difference of fluorescence intensity between the cells infected with silver nanoparticles treated and untreated Ad3. The transmission electron microscopy (TEM) showed that silver nanoparticles could directly damage the structure of Ad3 particle. The PCR amplification products of DNA isolated from silver nanoparticles treated Ad3 was decreased in a dose-dependent manner. The decreased DNA loads were also confirmed by real-time PCR experiment. The present study indicates silver nanoparticles exhibit remarkably inhibitory effects on Ad3 in vitro, which suggests silver nanoparticles could be a potential antiviral agent for inhibiting Ad3 infection.

  9. 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.

  10. Timber industry waste-teak ( Tectona grandis Linn.) leaf extract mediated synthesis of antibacterial silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Devadiga, Aishwarya; Shetty, K. Vidya; Saidutta, M. B.

    2015-08-01

    The current research article emphasizes efficacious use of teak leaves, an agro -biowaste from world's premier hardwood timber industry, for "green" synthesis of silver nanoparticles (AgNPs). Bioactive compounds of the leaves act as prolific reducing and stabilizing agents in AgNP synthesis. The characterization of the AgNPs synthesized using teak leaves revealed that the particles are spherical with an average size of 28 nm and the presence of bioactive compounds present in teak leaf extract as capping agents on the nanoparticles. A prominent decrease in the content of bioactive compounds such as polyphenols, antioxidants and flavonoids after the biosynthesis of AgNPs signifies that these class of compounds act as reductants and stabilizers during biosynthesis. The biosynthesized silver nanoparticles were also successfully evaluated for their antibacterial characteristics against waterborne pathogens, E. coli and S. aureus, with minimum inhibitory concentration of 25.6 μg/mL. Exploitation of agrowaste resources for synthesis of AgNPs curtails indiscriminate usage of food and commercial plant materials, rather contributing a sustainable way for effective plant waste biomass utilization and management. The biosynthesized AgNps have potential application in water purifiers, antibacterial fabrics, sports wear and in cosmetics as antibacterial agent and the process used for its synthesis being greener is highly beneficial from environmental, energy consumption and economic perspectives.

  11. Biosynthesis of silver nanoparticles using Euglena gracilis, Euglena intermedia and their extract.

    PubMed

    Li, Yong; Tang, Xiaoling; Song, Wenshuang; Zhu, Lina; Liu, Xingang; Yan, Xiaomin; Jin, Chengzhi; Ren, Qingguang

    2015-02-01

    Extracellular and intracellular biosynthesis of silver nanoparticles (AgNPs) by Euglena gracilis (EG) strain and Euglena intermedia (EI) strain are reported in this study. The obtained nanoparticles showed an absorption peak approximates 420 nm in the UV-visible spectrum, corresponding to the plasmon resonance of AgNPs. According to the result of inductively coupled plasma-atomic emission spectrometer, the intakes of silver ions by EI and EG are roughly equal. The transmission electron microscope (TEM) analysis of the successful in vivo and in vitro synthesised AgNPs indicated the sizes, ranging from 6 to 24 nm and 15 to 60 nm in diameter, respectively, and a spherical-shaped polydispersal of the particles. The successful formation of AgNPs has been confirmed by energy dispersive X-ray analysis connected to the TEM. The Fourier transform infrared spectroscopy measurements reveal the presence of bioactive functional groups such as amines are found to be the capping and stabilising agents of nanoparticles. To our knowledge, this is the first report where two kinds of Euglena microalga were used as the potential source for in vivo and in vitro biosynthesis of AgNPs.

  12. Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

    NASA Astrophysics Data System (ADS)

    Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A.; Landero-Figueroa, Julio

    2014-10-01

    The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV-VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag+) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg- 1 detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm.

  13. The effect of substrate material on silver nanoparticle antimicrobial efficacy.

    PubMed

    Dair, Benita J; Saylor, David M; Cargal, T Eric; French, Grace R; Kennedy, Kristen M; Casas, Rachel S; Guyer, Jonathan E; Warren, James A; Kim, Chang-Soo; Pollack, Steven K

    2010-12-01

    With the advent of nanotechnology, silver nanoparticles increasingly are being used in coatings, especially in medical device applications, to capitalize on their antimicrobial properties. The attractiveness of nanoparticulate silver systems is the expected increased antimicrobial efficacy relative to their bulk counterparts, which may be attributed to an increased silver ion (Ag+) solubility, and hence availability, that arises from capillarity effects in small, nanometer-sized particles. However, a change of the material upon which the antimicrobial nanoparticulate silver is deposited (herein called "substrate") may affect the availability of Ag+ ions and the intended efficacy of the device. We utilize both theory and experiment to determine the effect of substrate on ion release from silver particles in electrochemical environments and find that substrate surface charge, chemical reactivity or affinity of the surface for Ag+ ions, and wettability of the surface all affect availability of Ag+ ions, and hence antimicrobial efficacy. It is also observed that with time of exposure to deionized water, Ag+ ion release increases to a maximum value at 5 min before decreasing to undetectable levels, which is attributed to coarsening of the nanoparticles, and which subsequently reduces the solubility and availability of Ag+ ions. This coarsening phenomenon is also predicted by the theoretical considerations and has been confirmed experimentally by transmission electron microscopy.

  14. Bio-functionalized silver nanoparticles: a novel colorimetric probe for cysteine detection.

    PubMed

    Borase, Hemant P; Patil, Chandrashekhar D; Salunkhe, Rahul B; Suryawanshi, Rahul K; Kim, Beom S; Bapat, Vishwas A; Patil, Satish V

    2015-04-01

    Chemical interactions between nanoparticles and biomolecules are vital for applying nanoparticles in medicine and life science. Development of sensitive, rapid, low-cost, and eco-friendly sensors for the detection of molecules acting as disease indicator is need of an hour. In the present investigation, a green trend for silver nanoparticle synthesis was followed using leaf extract of Calotropis procera. Silver nanoparticles exhibited surface plasmon absorption peak at 421 nm, spherical shape with average size of 10 nm, and zeta potential of -22.4 mV. The as-synthesized silver nanoparticles were used for selective and sensitive detection of cysteine. Cysteine induces aggregation in stable silver nanoparticles owing to selective and strong interaction of -SH group of cysteine with silver nanoparticle surface. Cysteine-induced silver nanoparticle aggregation can be observed visually by change in color of silver nanoparticles from yellow to pink. Cysteine concentration was estimated colorimetrically by measuring absorption at surface plasmon wavelength. Limit of detection for cysteine using silver nanoparticles is ultralow, i.e., 100 nM. The mechanistic insight into cysteine detection by silver nanoparticles was investigated using FT-IR, TEM, DLS, and TLC analysis. Proposed method can be applied for the detection of cysteine in blood plasma and may give rise to a new insight into development of eco-friendly fabricated nanodiagnostic device in future.

  15. Biopersistence of silver nanoparticles in tissues from Sprague-Dawley rats.

    PubMed

    Lee, Ji Hyun; Kim, Yong Soon; Song, Kyung Seuk; Ryu, Hyun Ryol; Sung, Jae Hyuck; Park, Jung Duck; Park, Hyun Min; Song, Nam Woong; Shin, Beom Soo; Marshak, Daniel; Ahn, Kangho; Lee, Ji Eun; Yu, Il Je

    2013-08-01

    Silver nanoparticles are known to be distributed in many tissues after oral or inhalation exposure. Thus, understanding the tissue clearance of such distributed nanoparticles is very important to understand the behavior of silver nanoparticles in vivo. For risk assessment purposes, easy clearance indicates a lower overall cumulative toxicity. Accordingly, to investigate the clearance of tissue silver concentrations following oral silver nanoparticle exposure, Sprague-Dawley rats were assigned to 3 groups: control, low dose (100 mg/kg body weight), and high dose (500 mg/kg body weight), and exposed to two different sizes of silver nanoparticles (average diameter 10 and 25 nm) over 28 days. Thereafter, the rats were allowed to recover for 4 months. Regardless of the silver nanoparticle size, the silver content in most tissues gradually decreased during the 4-month recovery period, indicating tissue clearance of the accumulated silver. The exceptions were the silver concentrations in the brain and testes, which did not clear well, even after the 4-month recovery period, indicating an obstruction in transporting the accumulated silver out of these tissues. Therefore, the results showed that the size of the silver nanoparticles did not affect their tissue distribution. Furthermore, biological barriers, such as the blood-brain barrier and blood-testis barrier, seemed to play an important role in the silver clearance from these tissues.

  16. The Role of Organic Capping Layers of Platinum Nanoparticles in Catalytic Activity of CO Oxidation

    SciTech Connect

    Park, Jeong Y.; Aliaga, Cesar; Renzas, J. Russell; Lee, Hyunjoo; Somorjai, Gabor A.

    2008-12-17

    We report the catalytic activity of colloid platinum nanoparticles synthesized with different organic capping layers. On the molecular scale, the porous organic layers have open spaces that permit the reactant and product molecules to reach the metal surface. We carried out CO oxidation on several platinum nanoparticle systems capped with various organic molecules to investigate the role of the capping agent on catalytic activity. Platinum colloid nanoparticles with four types of capping layer have been used: TTAB (Tetradecyltrimethylammonium Bromide), HDA (hexadecylamine), HDT (hexadecylthiol), and PVP (poly(vinylpyrrolidone)). The reactivity of the Pt nanoparticles varied by 30%, with higher activity on TTAB coated nanoparticles and lower activity on HDT, while the activation energy remained between 27-28 kcal/mol. In separate experiments, the organic capping layers were partially removed using ultraviolet light-ozone generation techniques, which resulted in increased catalytic activity due to the removal of some of the organic layers. These results indicate that the nature of chemical bonding between organic capping layers and nanoparticle surfaces plays a role in determining the catalytic activity of platinum colloid nanoparticles for carbon monoxide oxidation.

  17. Environmental and human health risks of aerosolized silver nanoparticles.

    PubMed

    Quadros, Marina E; Marr, Linsey C

    2010-07-01

    Silver nanoparticles (AgNPs) are gaining attention from the academic and regulatory communities, not only because of their antimicrobial effects and subsequent product applications, but also because of their potential health and environmental risks. Whereas AgNPs in the aqueous phase are under intensive study, those in the atmosphere have been largely overlooked, although it is well established that inhalation of nanoparticles is associated with adverse health effects. This review summarizes the present state of knowledge concerning airborne AgNPs to shed light on the possible environmental exposure scenarios that may accompany the production and popularization of silver nanotechnology consumer products. The current understanding of the toxicity of AgNPs points toward a potential threat via the inhalation exposure route. Nanoparticle size, chemical composition, crystal structure, surface area, and the rate of silver ion release are expected to be important variables in determining toxicity. Possible routes of aerosolization of AgNPs from the production, use, and disposal of existing consumer products are presented. It is estimated that approximately 14% of silver nanotechnology products that have been inventoried could potentially release silver particles into the air during use, whether through spraying, dry powder dispersion, or other methods. In laboratory and industrial settings, six methods of aerosolization have been used to produce airborne AgNPs: spray atomization, liquid-flame spray, thermal evaporation-condensation, chemical vaporization, dry powder dispersion, and manual handling. Fundamental uncertainties remain about the fate of AgNPs in the environment, their short- and long-term health effects, and the specific physical and chemical properties of airborne particles that are responsible for health effects. Thus, to better understand the risks associated with silver nanotechnology, it is vital to understand the conditions under which AgNPs could become

  18. 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.

  19. Understanding the solvent polarity effects on surfactant-capped nanoparticles.

    PubMed

    Leekumjorn, Sukit; Gullapalli, Sravani; Wong, Michael S

    2012-11-01

    Understanding the molecular interactions between suspended nanoparticles (NPs) and the suspending solvent fluid may provide a useful avenue to create and to study exotic NP ensembles. This study focused on using a coarse-grained computational model to investigate the molecular interactions between oleate-capped NPs in various solvents, and to relate the results to experimental features of solvent-suspended, oleate-capped CdSe quantum dots (QDs). The QDs were modeled as a closed-shell fullerene molecule with an oleate-like ligand attached to each vertex. Solvent polarity was found to correlate to the simulation and experimental results more strongly than either dielectric constant or dipole moment. Computational results showed that the nonpolar solvents of hexane, toluene, and benzene (polarity index E(T)(N) < 0.120) kept NPs in suspension and solvated the oleate chains such that the oleate layer swelled to full extension. In contrast, as the most polar solvent tested (E(T)(N) = 1.000), water caused NPs to aggregate and precipitate. It partially solvated the oleate chains and compressed the layer to 86% of full extension. For solvents of intermediate polarity like ethanol, acetone, and chloroform, the oleate layer swelled with decreasing polarity index values, with rapid swelling occurring close to E(T)(N) = 0.307 (~50:50 vol % chloroform/acetone) below which QDs were colloidally stable. This study represents the first attempt to delineate the solvent effect on surfactant-coated NP hydrodynamic size, colloidal stability, and aggregation behavior.

  20. Chemical synthesis and antibacterial activity of novel-shaped silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Van Dong, Pham; Ha, Chu Hoang; Binh, Le Tran; Kasbohm, Jörn

    2012-06-01

    Silver nanoparticles are useful for medical applications due to their strong antibacterial activity. The antibacterial activity can be tuned by controlling the size and shape of the prepared silver nanoparticles. In this work, silver nanoparticles with different sizes and shapes were synthesized by solution phase routes, and their interactions with Escherichia coli were studied. Triangular silver nanoprisms were prepared by the reduction of silver nitrate at room temperature in the presence of polyvinylpyrrolidone, sodium citrate, hydrogen peroxide and sodium borohydride. Spherical silver nanoparticles were also prepared using silver nitrate as metal precursor and sodium citrate as well as sodium borohydride as reducing agents. The morphologies and structures of the nanoparticles were characterized by transmission electron microscopy, UV-visible spectroscopy and X-ray diffraction. The results indicated that spherical silver nanoparticles were obtained with different average sizes of 4, 21 and 40 nm, respectively. The edged silver nanoprisms containing mainly {111} lattice planes were obtained in the range size of 25 to 400 nm. The antibacterial study revealed that the edged triangular silver nanoprisms with {111} lattice planes exhibited the strongest antibacterial property, compared with spherical nanoparticles. Our study demonstrated that triangular silver nanoprisms with sharp edges also display a good antibacterial activity in comparison to other shaped nanoparticles.

  1. Biogenic silver and gold nanoparticles synthesized using red ginseng root extract, and their applications.

    PubMed

    Singh, Priyanka; Kim, Yeon Ju; Wang, Chao; Mathiyalagan, Ramya; El-Agamy Farh, Mohamed; Yang, Deok Chun

    2016-05-01

    In the present study, we report a green methodology for the synthesis of silver and gold nanoparticles, using the root extract of the herbal medicinal plant Korean red ginseng. The silver and gold nanoparticles were synthesized within 1 h and 10 min respectively. The nanoparticles generated were not aggregated, and remained stable for a long time, which suggests the nature of nanoparticles. The phytochemicals and ginsenosides present in the root extract assist in reducing and stabilizing the synthesized nanoparticles. The red ginseng root extract-generated silver nanoparticles exhibit antimicrobial activity against pathogenic microorganisms including Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus, and Candida albicans. In addition, the silver nanoparticles exhibit biofilm degrading activity against S. aureus and Pseudomonas aeruginosa. Thus, the present study opens up a new possibility of synthesizing silver and gold nanoparticles in a green and rapid manner using Korean red ginseng root extract, and explores their biomedical applications.

  2. Enhanced antibacterial activity of silver/polyrhodanine-composite-decorated silica nanoparticles.

    PubMed

    Song, Jooyoung; Kim, Hyunyoung; Jang, Yoonsun; Jang, Jyongsik

    2013-11-27

    This work describes the synthesis of silver/polyrhodanine-composite-decorated silica nanoparticles and their antibacterial activity. Polymerization of polyrhodanine proceeded preferentially on the surface of the silica nanoparticles where Ag(+) ions were located. In addition, the embedded Ag(+) ions were reduced to form metallic Ag nanoparticles; consequently, silver/polyrhodanine-composite nanoparticles (approximately 7 nm in diameter) were formed on the surface of the silica nanoparticles. The resulting nanostructure was investigated using electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy. The silver/polyrhodanine-nanocomposite-decorated silica nanoparticles exhibited excellent antimicrobial activity toward gram-negative Escherichia coli and gram-positive Staphylococcus aureus because of the antibacterial effects of the silver nanoparticles and the polyrhodanine. The silver/polyrhodanine-composite nanoparticles may therefore have potential for use as a long-term antibacterial agent.

  3. 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

    2015-02-05

    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 λmax 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.

  4. Attenuation of allergic airway inflammation and hyperresponsiveness in a murine model of asthma by silver nanoparticles

    PubMed Central

    Park, Hee Sun; Kim, Keun Hwa; Jang, Sunhyae; Park, Ji Won; Cha, Hye Rim; Lee, Jeong Eun; Kim, Ju Ock; Kim, Sun Young; Lee, Choong Sik; Kim, Joo Pyung; Jung, Sung Soo

    2010-01-01

    The use of silver in the past demonstrated the certain antimicrobial activity, though this has been replaced by other treatments. However, nanotechnology has provided a way of producing pure silver nanoparticles, and it shows cytoprotective activities and possible pro-healing properties. But, the mechanism of silver nanoparticles remains unknown. This study was aimed to investigate the effects of silver nanoparticles on bronchial inflammation and hyperresponsiveness. We used ovalbumin (OVA)-inhaled female C57BL/6 mice to evaluate the roles of silver nanoparticles and the related molecular mechanisms in allergic airway disease. In this study with an OVA-induced murine model of allergic airway disease, we found that the increased inflammatory cells, airway hyperresponsiveness, increased levels of IL-4, IL-5, and IL-13, and the increased NF-κB levels in lungs after OVA inhalation were significantly reduced by the administration of silver nanoparticles. In addition, we have also found that the increased intracellular reactive oxygen species (ROS) levels in bronchoalveolar lavage fluid after OVA inhalation were decreased by the administration of silver nanoparticles. These results indicate that silver nanoparticles may attenuate antigen-induced airway inflammation and hyperresponsiveness. And antioxidant effect of silver nanoparticles could be one of the molecular bases in the murine model of asthma. These findings may provide a potential molecular mechanism of silver nanoparticles in preventing or treating asthma. PMID:20957173

  5. Green synthesis of silver nanoparticles for the control of mosquito vectors of malaria, filariasis, and dengue

    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...

  6. Pseudorotaxane capped mesoporous silica nanoparticles for 3,4-methylenedioxymethamphetamine (MDMA) detection in water.

    PubMed

    Lozano-Torres, Beatriz; Pascual, Lluís; Bernardos, Andrea; Marcos, María D; Jeppesen, Jan O; Salinas, Yolanda; Martínez-Máñez, Ramón; Sancenón, Félix

    2017-03-23

    Mesoporous silica nanoparticles loaded with fluorescein and capped by a pseudorotaxane, formed between a naphthalene derivative and cyclobis(paraquat-p-phenylene) (CBPQT(4+)), were used for the selective and sensitive fluorogenic detection of 3,4-methylenedioxymethamphetamine (MDMA).

  7. Preparation and characterization of size controllable spherical silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Yang, Ai-ling; Li, Shun-pin; Wang, Yu-jin; Bao, Xi-chang; Yang, Ren-qiang

    2014-05-01

    By adjusting pH values of reactant system, the mass ratio of stabilizer/water and aging temperature, size controllable spherical silver nanoparticles (NPs) were synthesized. The properties of silver NPs are characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and ultraviolet visible (UV-VIS) absorption spectra. Within the pH values of 7.0-11.0, the aging temperature of 80 °C is better to improve silver NPs in shape to nearly sphere, concentrate size distribution and reduce aggregation than the aging temperature of 25 °C. The shape and dispersibility of silver NPs are the best when the pH of the reactant system is within 7.0-8.0. With pH of 7.5, aging at 80 °C, and stabilizer/water mass ratio of 1%, the spherical silver NPs with sizes of 50-70 nm were synthesized. The results are promising to be used to synthesize core/shell NPs when silver NPs are as core.

  8. PVP capped CdS nanoparticles for UV-LED applications

    SciTech Connect

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

    2015-06-24

    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.

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

    NASA Astrophysics Data System (ADS)

    Petkova, Galina A.; Záruba, Кamil; 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.

  10. Silver and Gold Nanoparticles Alter Cathepsin Activity In vitro

    NASA Astrophysics Data System (ADS)

    Speshock, Janice L.; Braydich-Stolle, Laura K.; Szymanski, Eric R.; Hussain, Saber M.

    2011-12-01

    Nanomaterials are being incorporated into many biological applications for use as therapeutics, sensors, or labels. Silver nanomaterials are being utilized for biological implants and wound dressings as an antiviral material, whereas gold nanomaterials are being used as biological labels or sensors due to their surface properties and biocompatibility. Cytotoxicity data of these materials are becoming more prevalent; however, little research has been performed to understand how the introduction of these materials into cells affects cellular processes. Here, we demonstrate the impact that silver and gold nanoparticles have on cathepsin activity in vitro. Cathepsins are important cellular proteases that are imperative for proper immune system function. We have selected to examine gold and silver nanoparticles due to the increased use of these materials in biological applications. This manuscript depicts how both of these types of nanomaterials affect cathepsin activity, which could impact the host's immune system and its ability to respond to pathogens. Cathepsin B activity decreases in a dose-dependent manner with all nanoparticles tested. Alternatively, the impact of nanoparticles on cathepsin L activity depends greatly on the type and size of the material.

  11. Silver and Gold Nanoparticles Alter Cathepsin Activity In vitro.

    PubMed

    Speshock, Janice L; Braydich-Stolle, Laura K; Szymanski, Eric R; Hussain, Saber M

    2011-12-01

    Nanomaterials are being incorporated into many biological applications for use as therapeutics, sensors, or labels. Silver nanomaterials are being utilized for biological implants and wound dressings as an antiviral material, whereas gold nanomaterials are being used as biological labels or sensors due to their surface properties and biocompatibility. Cytotoxicity data of these materials are becoming more prevalent; however, little research has been performed to understand how the introduction of these materials into cells affects cellular processes. Here, we demonstrate the impact that silver and gold nanoparticles have on cathepsin activity in vitro. Cathepsins are important cellular proteases that are imperative for proper immune system function. We have selected to examine gold and silver nanoparticles due to the increased use of these materials in biological applications. This manuscript depicts how both of these types of nanomaterials affect cathepsin activity, which could impact the host's immune system and its ability to respond to pathogens. Cathepsin B activity decreases in a dose-dependent manner with all nanoparticles tested. Alternatively, the impact of nanoparticles on cathepsin L activity depends greatly on the type and size of the material.

  12. Screening of filamentous fungi for antimicrobial silver nanoparticles synthesis.

    PubMed

    Ottoni, Cristiane Angélica; Simões, Marta Filipa; Fernandes, Sara; Dos Santos, Jonas Gomes; da Silva, Elda Sabino; de Souza, Rodrigo Fernando Brambilla; Maiorano, Alfredo Eduardo

    2017-12-01

    The present work had the goal of screening a batch of 20 fungal strains, isolated from sugar cane plantation soil, in order to identify those capable of biosynthesis of silver nanoparticles. These nanoparticles are known to have a large and effective application in clinical microbiology. Four strains were found to be capable of biosynthesis of silver nanoparticles. The biosynthesised nanoparticles were characterised by UV-vis spectroscopy, scanning electron microscopy, EDX, and XRD. They were found to have an average size of 30-100 nm, a regular round shape, and potential antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antimicrobial activity was found to be directly related to the nanoparticles concentration. Mycogenic synthesis of nanoparticles is a green biogenic process preferable to other alternatives. Because fungi are great producers of extracellular enzymes this process makes scaling-up an easier task with high importance for clinical microbiology on the fight against microbial resistance, as well as for other industrial applications.

  13. Novel synthesis of silver nanoparticles using 2,3,5,6-tetrakis-(morpholinomethyl) hydroquinone as reducing agent.

    PubMed

    Manivel, P; Balamurugan, A; Ponpandian, N; Mangalaraj, D; Viswanathan, C

    2012-09-01

    2,3,5,6-Tetrakis-(morpholinomethyl) hydroquinone (TMMH) was used as a reducing agent to synthesize spherical shaped silver nanoparticles in water-ethanol medium without using any stabilizing and capping agents. The reducing agent TMMH is prepared by Mannich-type reaction method and (1)H NMR, (13)C NMR and FT-IR spectroscopy techniques were used to characterize the compound (TMMH). The nature of bonding,