• Title/Summary/Keyword: Ag addition

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Synthesis of Cysteine Capped Silver Nanoparticles by Electrochemically Active Biofilm and their Antibacterial Activities

  • Khan, Mohammad Mansoob;Kalathil, Shafeer;Lee, Jin-Tae;Cho, Moo-Hwan
    • Bulletin of the Korean Chemical Society
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    • v.33 no.8
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    • pp.2592-2596
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    • 2012
  • Cysteine capped silver nanoparticles (Cys-AgNPs) have been synthesized by employing electrochemically active biofilm (EAB), $AgNO_3$ as precursor and sodium acetate as electron donor in aqueous solution at $30^{\circ}C$. Cys-AgNPs of 5-10 nm were synthesized and characterized by UV-Vis, FT-IR, XRD and TEM. Capping of the silver nanoparticles with cysteine provides stability to nanoparticles by a thiolate bond between the amino acid and the nanoparticle surface and hydrogen bonding among the Cys-AgNPs. In addition, the antibacterial effects of as-synthesized Cys-AgNPs have been tested against two pathogenic bacteria Escherichia coli (O157:H7) and Pseudomonas aeruginosa (PAO1). The results demonstrate that the as-synthesized Cys-AgNPs can proficiently inhibit the growth and multiplication of E. coli and P. aeruginosa.

Process Controllability and Stability in Organic Vapor Phase Deposition

  • Schwambera, M.;Gersdorff, M.;Reinhold, M.;Meyer, N.;Strauch, G.;Marheineke, B.;Heuken, M.;Zhou, T.X.;Ngo, T.;Brown, J.J.;Shtein, M.;Forrest, S.R.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.824-827
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    • 2004
  • High performance green $Ir(ppy)_3$-based phosphorescent OLEDs (PHOLEDs) have been fabricated by organic vapor phase deposition ($OVPD^{TM}$). In addition to demonstrating both efficiency and operational device lifetime comparable to devices built by vacuum thermal evaporation, we report on the controllability and stability of the $OVPD^{TM}$ process. Specifically, run-to-run and day-to-day deposition rate reproducibility of better than 2 % for three consecutive days is demonstrated.

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Preparation and characterization of expanded graphite/Ag nanoparticle composites for the improvement of thermal diffusion

  • Hong, Seok Hwan;Lee, Won Gyu
    • Korean Chemical Engineering Research
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    • v.56 no.3
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    • pp.410-415
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    • 2018
  • Expanded graphite (EG)/Ag nanoparticle composites were synthesized by the chemical reduction of Ag ions, followed by the addition of expanded graphite into an Ag reducing solution. The prepared composites showed uniform dispersion of Ag nanoparticles on the surface of expanded graphite and exhibited relatively higher thermal conductivities than those of pure expanded graphite. In the case of 10% Ag content in the composite, the thermal conductivity in the thickness direction was 78% higher than the pure expanded graphite. We suggest that EG/Ag nanoparticle composites are a strong candidate for advanced heat spreading material.

Synthesis, characterization, and antibacterial performance of Ag-modified graphene oxide reinforced electrospun polyurethane nanofibers

  • Pant, Bishweshwar;Park, Mira;Jang, Rae-Sang;Choi, Woo-Cheol;Kim, Hak-Yong;Park, Soo-Jin
    • Carbon letters
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    • v.23
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    • pp.17-21
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    • 2017
  • Polyurethane (PU) nanofibers containing graphene oxide (GO) and Ag doped functionalized reduced graphene oxide (Ag-RGO) were successfully prepared via the electrospinning technique. The uniform distribution of GO sheets along with Ag nanoparticle in the nanofibers was investigated by scanning electron microscopy and the elemental mapping technique. X-ray diffraction and thermal gravimetric analysis verified the presence of GO and Ag in the bicomposite nanofibrous mats. Antibacterial tests against Escherichia coli demonstrated that the addition of GO and Ag-RGO to the PU nanofiber greatly enhanced bactericidal efficiency. Overall, these features of the synthesized nanofibers make them a promising candidate material in the biomedical field for applications such as tissue engineering, wound healing, and drug delivery systems.

Photoinduced anisotropy in the Ag and Cu photodoped chalcogenide As-Ge-Se-S thin films (칼코게나이드 As-Ge-Se-S 박막에서 Ag와 Cu 광도핑에 의한 광유기 이방성)

  • 박종화;장선주;박정일;이영종;정홍배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.535-538
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    • 2000
  • We have investigated the photoinduced anisotropy in chalcogenide $As_{40}Ge_{10}Se_{15}S_{35}$ thin films, non-doped and photodoped by Ag and Cu. The films were exposed by the linearly polarized He-Ne laser light( $\lambda$=632.8nm). The Ag and Cu photodoping resulted in reducing the time of saturation photoinduced linearly dichroism. Also photoinduced linearly dichroism was increased up to maximum 184% by Ag photodoping and 138% by Cu photodoping, respectively. As the result of this study, the linearly dichroism can be interesting for different applications of photoinduced anisotropy. In addition, it will offer lots of information for the photodoping mechanism and analysis of chalcogenide thin film.

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AgNW-based functional polymer cantilever to improve maturity and contractility of cardiomyocytes (심근세포 성숙도 및 수축력 향상을 위한 AgNW 기반의 기능성 폴리머 캔틸레버)

  • Jeung, Min-young;Sim, Yu-ri;Yun, Ha-young;Kim, Dong-Su;Lee, Dong-Weon
    • Journal of Sensor Science and Technology
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    • v.30 no.3
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    • pp.185-189
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    • 2021
  • Herein, we propose a functional polymer cantilever to enhance maturation and contractile force of cardiomyocytes. The proposed cantilever consists of a surface-patterned polymer substrate and silver nanowires (AgNWs). The AgNWs are transferred to the PDMS substrate using conventional molding techniques. This thin metallic surface significantly improves the adhesion of cardiomyocyte on the surface-patterned PDMS with the hydrophobic characteristics. In addition, the use of AgNWs improves the visibility of the conducting PDMS substrate for the observation of cardiomyocyte through an inverted microscope. The AgNWs also assist in synchronizing each cardiomyocyte to maximize its contractile force.

Antigen Delivery Systems: Past, Present, and Future

  • Hyun-Jeong Ko;Yeon-Jeong Kim
    • Biomolecules & Therapeutics
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    • v.31 no.4
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    • pp.370-387
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    • 2023
  • The COVID-19 pandemic has increased demand for safe and effective vaccines. Research to develop vaccines against diseases including Middle East respiratory syndrome, Ebolavirus, human immunodeficiency virus, and various cancers would also contribute to global well-being. For successful vaccine development, the advancement of technologies such as antigen (Ag) screening, Ag delivery systems and adjuvants, and manufacturing processes is essential. Ag delivery systems are required not only to deliver a sufficient amount of Ag for vaccination, but also to enhance immune response. In addition, Ag types and their delivery systems determine the manufacturing processes of the vaccine product. Here, we analyze the characteristics of various Ag delivery systems: plasmids, viral vectors, bacterial vectors, nanoparticles, self-assembled particles, natural and artificial cells, and extracellular vesicles. This review provides insight into the current vaccine landscape and highlights promising avenues of research for the development and improvement of Ag delivery systems.