Multifunctional Nanorods Serving as Nanobridges To Modulate T Cell-Mediated Immunity

Son, Young Ju,Kim, Hyesung,Leong, Kam W.,Yoo, Hyuk Sang American Chemical Society 2013 ACS NANO Vol.7 No.11

<P>Electrodeposited nanorods serving as multivalent bridges were fabricated and surface-decorated with ligands for immune cells. Gold and nickel solutions were sequentially electrodeposited on nanoporous anodized disc templates and the template was dissolved to retrieve bisegmented nanorods with different lengths. Gold and nickel segmented nanorods were surface-immobilized with mannose and RGD peptides to prepare immune-cell recruiting nanorods. Surface-functionalization of nanorods were confirmed by fluorescence-labeling of each ligands and confocal microscopy. Dendritic cells and T cells were co-incubated with the surface-functionalized nanorods, and the proximity between the nanorods and the immune cells was visualized by variable pressure scanning electron microscopy and confocal microscopy. The long nanorods were associated with the immune cells, whereas the shorter nanorods were rather endocytosed by cells, suggesting a feasibility of the longer nanorods as bridging for the cells. Cytokine releases from the immune cells were monitored by cultivating lipopolysaccharide-activated dendritic cells with T cells. Interleukine-2 and interferon-γ release profiles showed a strong correlation with the length of the nanorod, where the 4 μm nanorods induced the highest levels of cytokine release compared to 1 or 2 μm nanorods. Thus, we concluded that the proximity of the immune cells increased by bridging the immune cells with the nanobridging system, which subsequently increased cytokine release by facilitating the antigen presentation process.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2013/ancac3.2013.7.issue-11/nn403275p/production/images/medium/nn-2013-03275p_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn403275p'>ACS Electronic Supporting Info</A></P>

Cr₂O₃ nanoparticle-functionalized WO₃ nanorods for ethanol gas sensors

Choi, Seungbok,Bonyani, Maryam,Sun, Gun-Joo,Lee, Jae Kyung,Hyun, Soong Keun,Lee, Chongmu Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.432 No.2

<P><B>Abstract</B></P> <P>Pristine WO<SUB>3</SUB> nanorods and Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorods were synthesized by the thermal evaporation of WO<SUB>3</SUB> powder in an oxidizing atmosphere, followed by spin-coating of the nanowires with Cr<SUB>2</SUB>O<SUB>3</SUB> nanoparticles and thermal annealing in an oxidizing atmosphere. Scanning electron microscopy was used to examine the morphological features and X-ray diffraction was used to study the crystallinity and phase formation of the synthesized nanorods. Gas sensing tests were performed at different temperatures in the presence of test gases (ethanol, acetone, CO, benzene and toluene). The Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorods sensor showed a stronger response to these gases relative to the pristine WO<SUB>3</SUB> nanorod sensor. In particular, the response of the Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorods sensor to 200ppm ethanol gas was 5.58, which is approximately 4.4 times higher that of the pristine WO<SUB>3</SUB> nanorods sensor. Furthermore, the Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorods sensor had a shorter response and recovery time. The pristine WO<SUB>3</SUB> nanorods had no selectivity toward ethanol gas, whereas the Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorods sensor showed good selectivity toward ethanol. The gas sensing mechanism of the Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorods sensor toward ethanol is discussed in detail.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pristine WO<SUB>3</SUB> nanorods and Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorods were synthesized. </LI> <LI> The Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorod sensor showed a stronger response to these gases than the pristine WO<SUB>3</SUB> nanorod sensor. </LI> <LI> The former sensor showed a shorter response and recovery time than the latter one. </LI> <LI> The Cr<SUB>2</SUB>O<SUB>3</SUB>-functionalized WO<SUB>3</SUB> nanorods sensor showed good selectivity toward ethanol. </LI> <LI> The underlying mechanisms for the enhanced sensing performance of the functionalized sensor are discussed in detail. </LI> </UL> </P>

Acetone Sensing of Multi-Networked WO3-NiO Core-Shell Nanorod Sensors

최승복,이재경,이우석,이충무,이완인 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.8

WO3-NiO core-shell nanorods were synthesized by thermal evaporation of a mixture of WO3 and graphite powders and immersion of the synthesized WO3 nanorods in an 20 mM of nickel(II) acetate tetrahydrate (Ni(OCOCH3)2·4H2O) solution followed by UV irradiation and annealing. Subsequently, multi-networked nanorod sensors were fabricated by connecting these nanostructures with electrodes. The sensing properties of pristine WO3 nanorod and WO3-NiO core-shell nanorod sensors toward acetone were examined. Subsequently, multi-networked nanorod sensors were fabricated by connecting these nanostructures with electrodes. The WO3-NiO core-shell nanorod sensor exhibited a stronger response to acetone gas and shorter response/recovery times than the pristine WO3 nanorod sensor. The pristine WO3 nanorods showed responses of approximately 1.36 to 200 ppm of CH3COCH3 at 300 C. On the other hand, the WO3-NiO core-shell nanorods showed responses of 4.4 to the same concentration of CH3COCH3 at the same temperature. The coreshell nanorods exhibited response and recovery times of 51 s and 59 s, respectively for 200 ppm of CH3COCH3. On the other hand, the pristine WO3 nanorods exhibited response and recovery times of 51 s and 59 s, respectively, for the same concentration of CH3COCH3. NiO coating enhanced the selectivity of the WO3 nanorods for acetone as well as the sensitivity of the WO3 nanorods. The underlying mechanism of the enhanced response of the WO3-NiO core-shell nanorod sensor is also discussed in detail.

Hydrothermally Grown Boron-Doped ZnO Nanorods for Various Applications: Structural, Optical, and Electrical Properties

김소아람,박형길,남기웅,윤현식,김병규,지익수,김영규,김익현,박영빈,Daeho Kang,임재영 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1

The structural, optical, and electrical properties of ZnO and BZO nanorods were investigated using fieldemission scanning electron microscopy, x-ray diffraction (XRD), photoluminescence (PL), and van der Pauw Hall-effect measurements. All the nanorods had grown well on the ZnO seed layers and were hexagonal. The BZO nanorods were shorter than the undoped ZnO nanorods, and the BZO nanorods grew shorter with increasing concentration of B to 2.0 at. % while the average length of the nanorods doped with 2.5 at. % B increased from 1620 to 1830 nm. The XRD patterns suggest that the amount of residual stress in the nanorods decreased with increasing concentration of B in the nanorods. The PL spectra showed near-bandedge and deep-level emissions, and B doping also varied the PL properties of the ZnO nanorods. The Halleffect data suggest that B doping also varied the electrical properties such as the carrier concentration, mobility, and resistivity of the ZnO nanorods.

Effects of passivation and postannealing on the photoluminescence properties of MgO/SiO₂ core‐shell nanorods

Jin, Changhyun,Lee, Jungkeun,Park, Sunghoon,Lee, Chongmu WILEY‐VCH Verlag 2011 Crystal research and technology Vol.46 No.3

<P><B>Abstract</B></P><P>MgO nanorods were grown by the thermal evaporation of Mg<SUB>3</SUB>N<SUB>2</SUB> powders on the Si (100) substrate coated with a gold thin film. The MgO nanorods grown on the Si (100) substrate were a few tens of nanometers in diameter and up to a few hundreds of micrometers in length. MgO/SiO<SUB>2</SUB> core‐shell nanorods were also fabricated by the sputter‐deposition of SiO<SUB>2</SUB>onto the MgO nanorods. Transmission electron microscopy (TEM) and X–ray diffraction (XRD) analysis results indicated that the cores and shells of the annealed core‐shell nanorods were a face‐centered cubic‐type single crystal MgO and amorphous SiO<SUB>2</SUB>, respectively. The photoluminescence (PL) spectroscopy analysis results showed that SiO<SUB>2</SUB> coating slightly decreased the PL emission intensity of the MgO nanorods. The PL emission of the MgO/SiO<SUB>2</SUB> core‐shell nanorods was, however, found to be considerably enhanced by thermal annealing and strongly depends on the annealing atmosphere. The PL emission of the MgO/SiO<SUB>2</SUB> core‐shell nanorods was substantially enhanced in intensity by annealing in a reducing atmosphere, whereas it was slightly enhanced by annealing in an oxidative atmosphere. The origin of the PL enhancement by annealing in a reducing atmosphere is discussed with the aid of energy‐dispersive X‐ray spectroscopy analyses. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)</P>

Preparation and Characterization of MgO Nanorods Sheathed with ZnS

진창현,박성훈,김현수,이종무 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.6

MgO nanorods have been grown by thermal evaporation of Mg<SUB>3</SUB>N<SUB>2</SUB> powders on Si (100) substrates using a VLS mechanism. The as-synthesized MgO nanorods were 100 - 200 nm in diameter and 5 - 7 μm in length. MgO/ZnS core-shell nanorods were also prepared by sputter-deposition of ZnS onto the nanorods. Transmission electron microscopy and X–ray diffraction analyses indicated that the MgO cores and the ZnS shells of the annealed core-shell nanorods were cubic-structured single crystals and amorhous, respectively. The photoluminescence (PL) measurements of the core-shell nanorods showed a broad emission band centered at approximately 605 nm in the yellow-orange region. The PL emission intensity of MgO nanorods increased with increasing the ZnS shell layer thickness up to the shell layer thickness of 30 nm and then decreased with continued increases in the shell layer thickness. The yellow-orange emission intensity of the MgO/ZnS core-shell nanorods was found to be significantly increased by annealing in an oxidizing atmosphere. The PL emission intensity of the core-shell nanorods was increased further by annealing in a reducing atmosphere. The origin of the PL enhancement by annealing is discussed.

A facile route to ionic liquids-functionalized ZnO nanorods for the fluorometric sensing of thiabendazole drug

Kaur, Narinder,Raj, Pushap,Singh, Amanpreet,Singh, Narinder,Kim, Deuk Young Elsevier 2018 Journal of molecular liquids Vol.261 No.-

<P>In this report, we introduce a simple and cost-effective hydrothermal method for the functionalization of ZnO nanorods with three different ionic liquids (ILs (1-3)) to check their sensing response with various drugs including thiabendazole, phenylbutazone, chloramphenicol, neomycin, and theophylline through fluorescence spectroscopy. The rod like-microstructure and hexagonal wurtzite structure of synthesized ZnO nanorods were examined with SEM-EDS and XRD techniques. On the other hand, ionic liquids-functionalized ZnO nanorods (ILs (1-3)/ZnO) exhibited various self-organized (layered-sheet similar to IL1, distorted nanorods similar to IL2, peanut beaded surface similar to IL3/ZnO) structures due to the intercalation of ILs on the surface of ZnO nanorods. Compared to ZnO nanorods, similar to ILs (1-3)/ZnO nanorods showed a blue shift in UV-absorption band which resulted to the variation in optical bandgap values. Ionic liquids-functionalized nanorods samples (ILs (1-3)/ZnO) have been selected for their recognition behaviour with available drug molecules using fluorescence spectroscopic technique. Interestingly, with the addition of thiabendazole drug molecules to two samples (ILs (1,3)/ZnO), a significant response corresponding to the peaks at similar to 350 nm and similar to 357 nm was observed, which led to the development of fluorescent sensors with a detection limit of 12 and 304 nM, respectively. (C) 2018 Elsevier B.V. All rights reserved.</P>

Effect of the pH of an Aqueous Solution on the Structural, Optical, and Photoresponse Properties of Hydrothermally Grown ZnO Nanorods and the Fabrication of a High Performance Ultraviolet Sensor

김동완,임재영 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.3

Of the various parameters related to the hydrothermal method for growing ZnO nanorods, the pHof the aqueous solution has a pronounced effect on the growth rate, morphology, and photoresponseof the fabricated ZnO nanorods. Here, we investigated the effects of the pH of the aqueous solutionon the structural, optical, and photoresponse properties of hydrothermally grown ZnO nanorods. When the pH of the solution was kept at 8, the ZnO nanorods exhibited improved vertical orientation,a higher growth rate, and directional growth along the (002) plane confirmed by scanningelectron microscopy. In contrast, the growth rate of the ZnO nanorods grown at a pH of 10 waslower, as the ZnO nanorods were dissolved because of the presence of excessive OH− ions in thesolution. The ultraviolet (UV) sensor based on the ZnO nanorods grown at a pH of 8 showed higherphotoresponsivity as compared to those of the sensors based on the ZnO nanorods grown at pHvalues of 7, 9, and 10. Thus, the use of an aqueous solution with the optimal pH values (8 in thiscase) resulted in uniform ZnO nanorods, which could be employed to fabricate a high-performanceUV sensor suitable for use in practical applications.

Enhanced H₂S sensing performance of TiO₂-decorated α-Fe₂O₃ nanorod sensors

Kheel, Hyejoon,Sun, Gun-Joo,Lee, Jae Kyung,Lee, Sangmin,Dwivedi, Ram Prakash,Lee, Chongmu Elsevier 2016 Ceramics international Vol.42 No.16

<P><B>Abstract</B></P> <P>Pristine and TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorods were synthesized via thermal oxidation of Fe thin foils, followed by the solvothermal treatment with titanium tetra isopropoxide (TTIP) and NaOH for TiO<SUB>2</SUB> nanoparticle-decoration. Subsequently, gas sensors were fabricated by connecting the nanorods with metal conductors. The structure and morphology of the pristine and TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorods were examined via X-ray diffraction and scanning electron microscopy, respectively. The gas sensing properties of the pristine and TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensors with regard to H<SUB>2</SUB>S gas were examined. The TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor showed a stronger response to H<SUB>2</SUB>S than the pristine Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor. The responses of the pristine and TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensors were 2.6 and 7.4, respectively, when tested with 200ppm of H<SUB>2</SUB>S at 300°C. The TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor also showed a faster response and recovery than the sensor made from pristine Fe<SUB>2</SUB>O<SUB>3</SUB> nanorods. Both sensors showed selectivity for H<SUB>2</SUB>S over NO<SUB>2</SUB>, SO<SUB>2</SUB>, NH<SUB>3</SUB>, and CO. The enhanced sensing performance of the TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor compared to that of the pristine Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor might be due to enhanced modulation of the conduction channel width, the decorated nanorods’ increased surface-to-volume ratios and the creation of preferential adsorption sites via TiO<SUB>2</SUB> nanoparticle decoration. The dominant sensing mechanism in the TiO<SUB>2</SUB> nanoparticle-decorated Fe<SUB>2</SUB>O<SUB>3</SUB> nanorod sensor is discussed in detail.</P>

Two-step Growth of ZnO Nanorods by Using MOCVD and Control of Their Diameters and Surface Densities

Hironori Fujisawa,Chiaki Kobayashi,Seiji Nakashima,Masaru Shimizu 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.8

We investigated the growth of ZnO nanorods on Al2O3(1120) substrates by using metalorganic chemical vapor deposition and demonstrated the ability to control their diameters and surface densities by using a two-step growth method. Following the first step, the ZnO nanorods were found to be densely packed due to random nucleation across the substrate surface, and their diameters and surface densities (numbers per unit area) were interdependent. During the second growth step,because nucleation sites were limited to the tips of existing nanorods, an upper limit was placed on the surface density of the second-layer nanorods. The surface density of the second-layer nanorods was also influenced by the reaction pressure during the second growth step. The diameter of the ZnO nanorods in the second layer was determined by the growth temperature during the second step and could be controlled independently of the surface density. Consequently, ZnO nanorods with small diameters (< 100 nm), low surface densities (< 10 µm−2) and large spacings (> 200 nm), which are difficult grow using a one-step growth method, were successfully produced. The deposition of 180-nm-thick Pb(Zr,Ti)O3 coatings onto sparsely-grown ZnO nanorods was also demonstrated.