• Title, Summary, Keyword: nanoparticle

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Nanoparticle Ferrite Multilayers Prepared by New Self-Assembling Sequential Adsorption Method

  • Kim, Yeong-Il;Kang, Ho-Jun;Kim, Don;Lee, Choong-Sub
    • Bulletin of the Korean Chemical Society
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    • v.24 no.5
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    • pp.593-599
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    • 2003
  • The nanoparticle magnetite of which diameter was about 3 nm was synthesized in a homogeneous aqueous solution without a template. The synthesized magnetite nanoparticle was easily oxidized to maghemite in an ambient condition. The magnetic properties of the ferrite nanoparticle show superparamagnetism at room temperature and its blocking temperature is around 93 K. Modifying the sequential adsorption method of metal bisphosphonate, we have prepared a multilayer thin film of the ferrite nanoparticle on planar substrates such as glass, quartz and Si wafer. In this multilayer the ferrite nanoparticle layer and an alkylbisphosphonate layer are alternately placed on the substrates by simple immersion in the solutions of the ferrite nanoparticle and 1, 10-decanediylbis (phosphonic acid) (DBPA), alternately. This is the first example, as far as we know, of nanoparticle/alkyl-bisphosphonate multilayer which is an analogy of metal bisphosphonate multilayer. UV-visible absorption and infrared reflection-absorption studies show that the growth of each layer is very systematic and the film is considerably optically transparent to visible light of 400-700 nm. Atomic force microscopic images of the film show that the surface morphology of the film follows that of the substrate in μm-scale image and the nanoparticle-terminated surface is differentiated from the DBPA-terminated one in nm-scale image. The magnetic properties of this ferrite/DBPA thin film are almost the same as those of the ferrite nanoparticle powder only.

Nanoparticle effect on the mechanical properties of polymer composites (에폭시수지의 물성에 미치는 나노입자의 영향)

  • Moon, Chang-Kwon;Kim, Bu-Ahn
    • Journal of the Korea Society For Power System Engineering
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    • v.19 no.5
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    • pp.12-16
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    • 2015
  • $TiO_2$ nanoparticle can be used for the improvement of performance of the epoxy resin composites. In this study, the effect of the size of $TiO_2$ nanoparticle on the mechanical properties for the epoxy resin composites was investigated. The size of $TiO_2$ nanoparticle was easily controlled by heat treatment. The heat treatment of $TiO_2$ nanoparticle was conducted between $700^{\circ}C$ and $900^{\circ}C$. The obtained size of $TiO_2$ nanoparticle was 20 nm, 100 nm and 200 nm respectively. As the diameter of $TiO_2$ nanoparticle is smaller, the epoxy resin composite specimen showed higher tensile strength. It was also found that Vickers hardness of epoxy resin was increased by the addition of $TiO_2$ nanoparticle. But the size of $TiO_2$ nanoparticle did not strongly affected to the Vickers hardness of this material. The fracture surface of epoxy resin showed clear difference by the size of $TiO_2$ nanoparticlet.

Polyvalent Nanoparticle-oligonudleotide conjugates: Synthesis, Properties, and Biodiagnostic/Therapeutic Applications

  • Lee, Jae-Seung
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.7.2-7.2
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    • 2009
  • Polyvalent nanoparticle-DNA conjugates exhibit a variety of unique features such as programmable assembly and disassembly, sharp melting transitons, intense optical properties, high stability, enhanced binding properties, and easy fabrication of the surface nature by chemical and physical modification. The unique properties of nanoparticle-DNA conjugates enable one to build up a number of versatile assay schemes for the detection of various targets. In addition, nanoparticle-RNA conjugates also demonstrate great promise of therapeutic applications in the context of RNA interference when combined with polymeric materials. In this presentation, representative examples of each aspect of nanoparticle-oligonucleotide conjugates will be discussed.

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Fabrication of Hemoglobin/Silver Nanoparticle Heterolayer for Electrochemical Signal-enhanced Bioelectronic Application

  • Lee, Taek;Yoon, Jinho;Choi, Jeong-Woo
    • Korean Chemical Engineering Research
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    • v.55 no.4
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    • pp.556-560
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    • 2017
  • A hemoglobin/silver nanoparticle heterolayer was fabricated for bioelectronic device with electrochemical signal-enhancement effect. As a device element, a hemoglobin, the metalloprotein, contained the heme group that showed the redox property was introduced for charge storage element. For electron transfer facilitation, a silver nanoparticle was introduced for electrochemical signal facilitation, the hemoglobin was immobilized onto Au substrate using chemical linker 6-mercaptohexanoic acid (6-MHA). Then, the silver nanoparticle was immobilized onto fabricated hemoglobin/6-MHA heterolayers by layer-by-layer (LbL) method. The surface morphology and surface roughness of fabricated heterolayer were investigated by atomic force microscopy (AFM). The redox property of hemoglobin/silver nanoparticle heterolayer was investigated by a cyclic voltammetry (CV) experiment for obtaining an oxidation potential and reduction potential. Moreover, for the assessing charge storage function, a chronoamperometry (CA) experiment was conducted to hemoglobin/silver nanoparticle-modified heterolayer electrode using oxidation and reduction potentials, respectively. Based on the results, the fabricated hemoglobin/silver nanoparticle heterolayer showed that an increased charge storage effect compared to hemoglobin monolayer-modified electrode.

Clinical effect of chewing gum containing chlorhexidine nanoparticles on the dental plaque and gingivitis (클로르헥시딘 nanoparticle을 함유하는 chewing gum이 치태 및 치은염에 미치는 영향)

  • Lee, Gwang-Hee;Nam, Young-Ok;Kim, Mi-Jeong
    • Journal of Korean society of Dental Hygiene
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    • v.1 no.1
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    • pp.89-99
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    • 2001
  • Estimating by clinical index the efficacy of three cases, where chewing gum is mixed with nanoparticle containing chlorhexidine, where chewing gum doesn't contain neither of them, and where with chlorhexidine only, this study has come to the following conclusion. 1. The chewing gum with chlorhexidine and chlorhexidine nanoparticle has shown more reduction of plaque index and gingival index than that with no chlorhexidine. 2. There could be seen a difference between the gum with chlorhexidine and the gum with chlorhexidine nanoparticle. 3. The gum with chlorhexidine nanoparticle has shown less level of plaque index than that chlorhexidine, which difference was only slight. 4. The gum with chlorhexidine nanoparticle wasn't absorved any tooth coloring. To put these results together, it is proposed that mixing chewing gum with chlorhexidine nanoparticle can be an efficient application.

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A Pathway to Microdomain Alignment in Block Copolymer/Nanoparticle Thin Films under Electric Field

  • Bae, Joonwon
    • Bulletin of the Korean Chemical Society
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    • v.35 no.9
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    • pp.2689-2693
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    • 2014
  • The control over microstructure in block copolymer thin films using external electric fields has become an interesting research topic. In this article, the effect of nanoparticle on the microdomain alignments in block copolymer (polystyrene-b-poly(2-vinylpyridine)/nanoparticle (Au) thin films under electric fields has been examined with transmission electron microscopy. The homogeneous dispersion of Au nanoparticles into the block copolymer matrix was achieved by surface modification of nanoparticles with compatible ligands. Compared with the phenomenon seen in the pristine block copolymer thin films, a peculiar alignment behavior was observed in the block copolymer/nanoparticle hybrid thin films under electric fields. In addition, the different pathways observed in the pristine and nanoparticle incorporated block copolymer thin films were also monitored as a function of exposure time. This work can provide the fundamental information for understanding microdomain alignment in block copolymer/nanoparticle thin films under external electric fields.

Synthesized Nanoparticle Trapping in Capacitively Coupled Plasma

  • Yu, Gwang-Ho;Kim, Jeong-Hyeong;Yu, Sin-Jae;Seong, Dae-Jin;Sin, Yong-Hyeon;Jang, Hong-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.578-578
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    • 2013
  • We proposed a method for synthesized nanoparticle trapping in capacitively coupled plasma (CCP) reactor. The nanoparticle in nonthermal plasma can be negatively charged by a charged particle in plasma. Thus, it can be placed between sheath and bulk plasma with zero net force on nanoparticle. However, synthesized nanoparticle can be pumped out due to the neutral drag force when the large size of sheath thickness. We try to make a potential well using the sheath for trapping the synthesized nanoparticle.

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Ultrafine ITO Nanoparticle for Ink Jet Printing

  • Hong, Sung-Jei;Kim, Yong-Hoon;Han, Jeong-In
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.467-470
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    • 2007
  • Ultrafine Indium tin oxide (ITO) nanoparticle was successfully fabricated by low temperature synthetic method (LTSM). Mean size of ITO nanoparticle is 5 nm, and uniformly dispersed with (222) orientated cubic structure. Using the nanoparticle, ITO thin film with good optical and electrical properties was fabricated by inkjet printing.

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Radiolabeling of nanoparticle for enhanced molecular imaging

  • Kim, Ho Young;Lee, Yun-Sang;Jeong, Jae Min
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.3 no.2
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    • pp.103-112
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    • 2017
  • The combination of nanoparticle with radioisotope could give the in vivo information with high sensitivity and specificity. However, radioisotope labeling of nanoparticle is very difficult and radioisotopes have different physicochemical properties, so the radioisotope selection of nanoparticle should be carefully considered. $^{18}F$ was first option to be considered for labeling of nanoparticle. For the labeling of $^{18}F$ with nanoparticle, Prosthetic group is widely used. Iodine, another radioactive halogen, is often used. Since radioiodine isotopes are various, they can be used for different imaging technique or therapy in the same labeling procedures. $^{99m}Tc$ can easily be obtained as pertechnatate ($^{99m}{TcO_4}^-$) by commercial generator. Ionic $^{68}Ga$ (III) in dilute HCl solution is also obtained by generator system, but $^{68}Ga$ can be substituted for $^{67}Ga$ because of the short half-life (67.8 min). $^{64}Cu$ emits not only positron but also ${\beta}-particle$. Therefore $^{64}Cu$ can be used for imaging and therapy at the same time. These radioactive metals can be labeled with nanoparticle using the bifunctional chelator. $^{89}Zr$ has longer half-life (78.4 h) and is used for the longer imaging time. Unlike different metals, $^{89}Zr$ should use the other chelate such as DFO, 3,4,3-(LI-1,2-HOPO) or DFOB.