• Title, Summary, Keyword: Ag nanoparticles

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Fruit Mediated Synthesis of Gold and Silver Nanoparticles Using Lycium chinense and Their Antimicrobial Activity

  • Chokkalingam, Mohan;Huo, Yue;Kang, Jong-Pyo;Mathiyalagan, Ramya;Kim, Yoen-Ju;Yang, Deok-Chun
    • Proceedings of the Plant Resources Society of Korea Conference
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    • pp.94-94
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    • 2018
  • The gold (LC-AuNPs) and silver (LC-AgNPs) nanoparticles were rapidly synthesized by fruit extract of Lycium chinense within 1.15 and 25 min respectively in an eco-friendly way. The synthesized nanoparticles confirmed by relevant surface plasmon resonance peaks for gold and silver nanoparticles at 536 and 480 nm, respectively. FE-TEM results revealed that LC-AuNPs were 20-50 nm and LC-AgNPs were 50-100 nm. The maximum distribution of gold, silver elements and the crystallographic nature of synthesized were confirmed using EDX, elemental mapping and XRD. LC-AgNPs showed inhibitory activity against pathogenic microorganisms such as E. coli and S. aureus, whereas LC-AuNPs did not show inhibitory activity. The LC-AgNps nanoparticles exhibited significant cytotoxicity to human breast cancer MCF7 cell line and less cytotoxicity to non-diseased RAW264.7 (murine macrophage) cells whereas LC-AuNps showed minimal toxicity to both cell lines. In-depth research on this rapid, facile and greenery nanoparticles may play a potential role in biomedical applications.

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Phytogenic silver nanoparticles (Alstonia scholaris) incorporated with epoxy coating on PVC materials and their biofilm degradation studies

  • Supraja, Nookala;Tollamadugu, Naga Venkata Krishna Vara Prasad;Adam, S.
    • Advances in nano research
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    • v.4 no.4
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    • pp.281-294
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    • 2016
  • The advantages of nano-scale materials (size 1-99 nm in at least in one dimension) could be realized with their potential applications in diversified avenues. Herein, we report for the first time on the successful synthesis of homogeneous epoxy coatings containing phytogenic silver nanoparticles (Ag) on PVC and glass substrates by room-temperature curing of fully mixed epoxy slurry diluted by acetone. Alstonia scholaris bark extract was used to reduce and stabilize the silver ions. The surface morphology and mechanical properties of these coatings were characterized using the techniques like, UV-Vis (UV-Visible) spectrophotometry, X-ray diffraction (XRD), Fourier transform infrared spectrophotometry (FT-IR), Epifluorescence microscopy and scanning electron microscopy (SEM). The effect of incorporating Ag nanoparticles on the biofilm (scale) resistant epoxy-coated PVC was investigated by total viable counts ($CFU/cm^2$) from epoxy coating from (Initial) $1^{st}$ day to $25^{th}$ days. The phytogenic Ag nanoparticles were found to be significantly improving the microstructure of the coating matrix and thus enhanced the anti-biofilm performance of the epoxy coating. In addition, the antimicrobial mechanism of Ag nanoparticles played an important role in improving the anti-biofilm performance of these epoxy coatings.

Antibacterial Activity of CNT-Ag and GO-Ag Nanocomposites Against Gram-negative and Gram-positive Bacteria

  • Yun, Hyosuk;Kim, Ji Dang;Choi, Hyun Chul;Lee, Chul Won
    • Bulletin of the Korean Chemical Society
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    • v.34 no.11
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    • pp.3261-3264
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    • 2013
  • Carbon nanocomposites composed of carbon nanostructures and metal nanoparticles have become one of useful materials for various applications. Here we present the preparation and antibacterial activity of CNT-Ag and GO-Ag nanocomposites. Their physical properties were characterized by TEM, XPS, and Raman measurements, revealing that size-similar and quasi-spherical Ag nanoparticles were anchored to the surface of the CNT and GO. The antibacterial activities of CNT-Ag and GO-Ag were investigated using the growth curve method and minimal inhibitory concentrations against Gram-negative and Gram-positive bacteria. The antibacterial activities of the carbon nanocomposites were slightly different against Gram-positive and Gram-negative bacteria. The proposed mechanism was discussed.

Study of metal dopants and/or Ag nanoparticles incorporated direct-patternable ZnO film by photochemical solution deposition

  • Kim, Hyun-Cheol;Reddy, A.Sivasankar;Park, Hyung-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.368-368
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    • 2007
  • Zinc oxide (ZnO) has drawn much interest as a potential transparent conducting oxide (TCO) for applying to solar cell and front electrode of electro-luminescent devices. For the enhancement of electrical property of TCOs, dopant introduction and hybridization with conductive nanoparticles have been investigated. In this work, ZnO films were formed on glass substrate by using photochemical solution deposition of Ag nanoparticles dispersed or various metal (Ag, Cd, In, or Sn) contained photosensitive ZnO solutions. The usage of photosensitive solution permits us to obtain a micron-sized direct patterning of ZnO film without using conventional dry etching procedure. The structural, optical, and electrical characteristics of ZnO films with the introduction of metal dopants with/without Ag nanoparticles have been investigated to check whether there is a combined effect between metal dopants and Ag nanoparticles on the characteristics of ZnO film. The phase formation and crystallinity of ZnO film were monitored with X-ray diffractometer. The optical transmittance measurement was carried out using UV-VIS-NIR spectrometer and the electrical properties such as sheet resistance and conductivity were observed by using four-point probe.

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Fabrication of Biogenic Antimicrobial Silver Nanoparticles by Streptomyces aegyptia NEAE 102 as Eco-Friendly Nanofactory

  • El-Naggar, Noura El-Ahmady;Abdelwahed, Nayera A.M.;Darwesh, Osama M.M.
    • Journal of Microbiology and Biotechnology
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    • v.24 no.4
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    • pp.453-464
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    • 2014
  • The current research was focused on the extracellular biosynthesis of bactericidal silver nanoparticles (AgNPs) using cell-free supernatant of a local isolate previously identified as a novel Streptomyces aegyptia NEAE 102. The biosynthesis of silver nanoparticles by Streptomyces aegyptia NEAE 102 was quite fast and required far less time than previously published strains. The produced particles showed a single surface plasmon resonance peak at 400 nm by UV-Vis spectroscopy, which confirmed the presence of AgNPs. Response surface methodology was chosen to evaluate the effects of four process variables ($AgNO_3$ concentration, incubation period, pH levels, and inoculum size) on the biosynthesis of silver nanoparticles by Streptomyces aegyptia NEAE 102. Statistical analysis of the results showed that the linear and quadratic effects of incubation period, initial pH, and inoculum size had a significant effect (p < 0.05) on the biosynthesis of silver nanoparticles by Streptomyces aegyptia NEAE 102. The maximum silver nanoparticles biosynthesis (2.5 OD, at 400 nm ) was achieved in runs number 5 and 14 under the conditions of 1 mM $AgNO_3$ (1-1.5% (v/v)), incubation period (72-96 h), initial pH (9-10), and inoculum size (2-4% (v/v)). An overall 4-fold increase in AgNPs biosynthesis was obtained as compared with that of unoptimized conditions. The biosynthesized silver nanoparticles were characterized using UV-VIS spectrophotometer and Fourier transform infrared spectroscopy analysis, in addition to antimicrobial properties. The biosynthesized AgNPs significantly inhibited the growth of medically important pathogenic gram-positive (Staphylococcus aureus) and gram-negative bacteria (Pseudomonas aeruginosa) and yeast (Candida albicans).

Enhanced Blue Emission in Er3+/Yb33+ Doped Glass-ceramics Containing Ag Nanoparticles and ZnO Nanocrystals

  • Bae, Chang-hyuck;Lim, Ki-Soo
    • Current Optics and Photonics
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    • v.3 no.2
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    • pp.135-142
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    • 2019
  • We report the precipitation of ZnO nanocrystals, Ag-clusters, and Ag nanoparticles in Ag/Er/Yb doped borate glasses by furnace annealing and $CO_2$ laser annealing. The XRD analysis revealed the precipitation of ZnO and Ag phases. The absorption spectra, the TEM and energy dispersive spectroscopy (EDS) revealed the incorporation of Er and Yb ions into ZnO nanocrystals formed by a laser technique and showed the surface plasmon band of Ag nanoparticles. The down-converted blue emission intensity of $Er^{3+}$ ions obtained under 365 nm excitation was enhanced by more than a hundred times in the glass treated by furnace annealing, mainly due to the energy transfer from Ag-clusters. Moreover, we discussed the contribution of Ag nanoparticles and defects to emission characteristics in the glasses treated by two annealing techniques. Up-conversion emissions of the $Er^{3+}$ ions under 980 nm excitation were enhanced due to the incorporation of $Er^{3+}$ and $Yb^{3+}$ ions into ZnO nanocrystals after thermal treatments.

Fusarium mangiferae as New Cell Factories for Producing Silver Nanoparticles

  • Hamzah, Haider M.;Salah, Reyam F.;Maroof, Mohammed N.
    • Journal of Microbiology and Biotechnology
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    • v.28 no.10
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    • pp.1654-1663
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    • 2018
  • Finding a safe and broad-spectrum medication is a goal of scientists, pharmacists, and physicians, but developing and fabricating the right medicine can be challenging. The current study describes the formation of silver nanoparticles (AgNPs) by Fusarium mangiferae. It involves the antibiofilm activity of the nanoparticles against Staphylococcus aureus. It also involves cytotoxic effect against mammalian cell lines. Well-dispersed nanoparticles are formed by F. mangiferae. The sizes of the nanoparticles were found to range from 25 to 52 nm, and UV-Vis scan showed absorption around 416-420 nm. SEM, TEM, and AFM results displayed spherical and oval shapes. Furthermore, the FTIR histogram detected amide I and amide II compounds responsible for the stability of AgNPs in an aqueous solution. AgNPs were observed to decrease the formation of biofilm at 75% (v/v). DNA reducing, smearing, and perhaps fragmentation were noticed after treating the bacterial cells with 50% (v/v). Additionally, cell lysis was detected releasing proteins in the supernatant. It was also observed that the AgNPs have the ability to cause 59% cervical cancer cell line (HeLa) deaths at 25% (v/v), however, they showed about 31% toxicity against rat embryo fibroblast transformed cell lines (REF). The results of this study prove the efficiency of AgNPs as an antibiofilm against S. aureus, suggesting that AgNPs could be an alternative to antibiotics. It must also be emphasized that AgNPs displayed cytotoxic behavior against mammalian cell lines. Further studies are needed for assessing risk in relation to the possible benefit of prescribing AgNPs.

Preparation of Ag Nanoparticles by Templating Poly(vinyl chloride)-g-poly(styrene sulfonic acid) Graft Copolymer Membrane (Poly(vinyl chloride)-g-poly(styrene sulfonic acid) 가지형 공중합체막을 이용한 은 나노입자 제조)

  • Byun, Su-Jin;Seo, Jin-Ah;Chi, Won-Seok;Shul, Yong-Gun;Kim, Jong-Hak
    • Membrane Journal
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    • v.21 no.1
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    • pp.39-45
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    • 2011
  • An amphiphilic graft copolymer consisting of a poly(vinyl chloride) (PVC) backbone and poly(styrene sulfonic acid) (PSSA) side chains (PVC-g-PSSA) was synthesized via atom transfer radical polymerization (ATRP). This polymer electrolyte membrane was ion-exchanged to Ag ions by immersing in 10 wt% $AgNO_3$ aqueous solution and templated the growth of Ag nanoparticles by a reducing agent. The formation of Ag nanoparticles was confirmed using UV-visible spectroscopy and X-ray diffraction (XRD). Transmission electron microscopy (TEM) revealed that utilization of $NaBH_4$ was the most effective in the formation of Ag nanoparticles with 10~15 nm in size. The formation of Ag nanoparticles was also strongly affected by the concentration of reducing agent and reduction time.

Green Synthesis of Silver Nanoparticles Using Cell Extracts of Anabaena doliolum and Screening of Its Antibacterial and Antitumor Activity

  • Singh, Garvita;Babele, Piyoosh K.;Shahi, Shailesh K.;Sinha, Rajeshwar P.;Tyagi, Madhu B.;Kumar, Ashok
    • Journal of Microbiology and Biotechnology
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    • v.24 no.10
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    • pp.1354-1367
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    • 2014
  • In the present work, we describe a simple, cheap, and unexplored method for "green" synthesis of silver nanoparticles using cell extracts of the cyanobacterium Anabaena doliolum. An attempt was also made to test the antimicrobial and antitumor activities of the synthesized nanoparticles. Analytical techniques, namely UV-vis spectroscopy, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and TEM-selected area electron diffraction, were used to elucidate the formation and characterization of silver-cyanobacterial nanoparticles (Ag-CNPs). Results showed that the original color of the cell extract changed from reddish blue to dark brown after addition of silver nitrate solution (1 mM) within 1 h, suggesting the synthesis of Ag-CNPs. That the formation Ag-CNPs indeed occurred was also evident from the spectroscopic analysis of the reaction mixture, wherein a prominent peak at 420 nm was noted. TEM images revealed well-dispersed, spherical Ag-CNPs with a particle size in the range of 10-50 nm. The X-ray diffraction spectrum suggested a crystalline nature of the Ag-CNPs. FTIR analysis indicated the utilization of a hydroxyl (-OH) group in the formation of Ag-CNPs. Ag-CNPs exhibited strong antibacterial activity against three multidrug-resistant bacteria. Additionally, Ag-CNPs strongly affected the survival of Dalton's lymphoma and human carcinoma colo205 cells at a very low concentration. The Ag-CNPs-induced loss of survival of both cell types may be due to the induction of reactive oxygen species generation and DNA fragmentation, resulting in apoptosis. Properties exhibited by the Ag-CNP suggest that it may be used as a potential antibacterial and antitumor agent.

Facile Preparation of Ag2S-CNT Nanocomposites with Enhanced Photo-catalytic Activity

  • Meng, Ze-Da;Sarkar, Sourav;Zhu, Lei;Ullah, Kefayat;Ye, Shu;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
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    • v.51 no.1
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    • pp.1-6
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    • 2014
  • Here we report improved photo-catalytic effect of $Ag_2S$ under visible light using carbon nano-tubes (CNT) modified with $Ag_2S$ nanoparticles. The optical properties, structural properties and compositional analysis, as well as the photo-electrochemical properties of the prepared composites were investigated. It was found that the photocurrent density, and the photo-catalytic effect, was increased by modification of CNT in this way. Compared with the separate effects of $Ag_2S$ and CNT nanoparticles, the photocatalytic effect of CNT-modified-with-$Ag_2S$ composites, increased significantly due to a synergistic effect between the CNT and the $Ag_2S$ nanoparticles.