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71.
Eun-Sil Park Dae-Hwan Jang Young-In Lee Chan Woo Jung Dong woo Lim Bum Sung Kim Young-keun Jeong Nosang V. Myung Yong-Ho Choa 《Research on Chemical Intermediates》2014,40(7):2565-2570
Conducting polymers are excellent sensing materials in the design of bioanalytical sensors because of their electronic conductivity, low energy optical transitions, biocompatibility, and room temperature operation. Among them, Polypyrrole (Ppy) is one of the most extensively used conducting polymers because of a number of properties such as redox activity, rapid electron transfer, and ability to link a variety of biomolecules to pyrrole groups by chemical treatment. In this study, Ppy nanowires were synthesized by an electrospinning method. The nanowires were prepared from a solution mixture of Ppy and poly(ethylene oxide). The method of detection in such a device is based on the selective binding of antigen onto an antibody that is covalently attached to the nanowires. Thus, anti-IgG was immobilized on Ppy nanowires using an EDC {[N-(3-dimethyl aminopropyl)-N2-ethylcarbodiimide hydrochloride]}-NHS(N-hydrosuccinimide) modified technique. Fluorescence images of BSA–FITC (fluorescein isothiocyanate labeling of bovine serum albumin) conjugation demonstrated that antibody was functionalized on the Ppy nanowires without non-specific binding and facilitated selective detection of antigen. Current–voltage (I–V) characterization was used to monitor the change in the conductivity of nanowires while the specific binding interaction occurred. These results of electrical properties enable Ppy nanowire-based biosensors to detect biomolecules in real-time. 相似文献
72.
Transition Metal Chemistry - A facile synthetic approach has been adopted towards the synthesis of (2R,3R)-N2,N3-bis((S)-1-phenylethyl)butane-2,3-diamine via demetalation of its dichloro Zn(II)... 相似文献
73.
74.
The mixed crystal (K1-xCsx)2ZnCl4 with x = 0, 0.001, 0.01, 0.1, and 0.2 with optical quality has been grown by the Czochralski method. Using the Atomic Absorption Spectroscopy (AAS) and Energy Dispersive Spectroscopy (EDS), we determined the amount of Cs ion included in the mixed crystal. By using of DTA and DSC, we observed the change of Tc and Ti. The thermal hysteresis in the dielectric constants show strong dependence on the thermal process and on the amount of impurity which are explained by the influence of the thermal process and impurity, respectively on the creation, annihilation, and growth of discommensuration (DC). 相似文献
75.
76.
Dae Hwan Kim Seokhyeon Kang Ji Hoon Hong Ahran Kim Hanseol Jeong 《Molecular Crystals and Liquid Crystals》2019,685(1):2-6
AbstractThermo-responsive polymers have attracted much attention in recent years because they can provide a variety of applications for smart devices, but the lack of sufficient mechanical properties and late response rate of the polymers limit their applications. In the current work, we fabricated polymer nanocomposites made from poly(vinyl methyl ether) and nanofillers with photothermal conversion property such as graphene oxide, antimony tin oxide nanoparticles, and silver nanoplates. The prepared nanocomposites showed rapidly reversible and reliable transparent-opaque transitions during the repeated heating and cooling processes, suggesting that they can be applied to smart window applications. 相似文献
77.
78.
H S Lee C K Jeong H M Lee S J Choi K S Do K Kim Y H Kim 《Journal of chromatography. A》1999,848(1-2):179-184
The need for a rapid, sensitive and reliable analytical method for cyanobacterial toxins, microcystins, has been emphasized by the awareness of toxic cyanobacteria as a human-health risk through drinking water. A new high-performance liquid chromatographic method with column switching was developed for the determination of microcystin-LR, -RR and -YR from water samples without pre-purification. The filtered water sample was passed through a Zorbax CN precolumn at a flow-rate of 3 ml/min for on-line trace enrichment. After valve switching, concentrated analytes were eluted in back-flush mode and separated on a Luna C18 column with a gradient of acetonitrile -20 mM phosphate buffer (pH 2.5). The method showed excellent precision, accuracy and speed with detection limits of 0.02 microgram/ml from 100 ml of surface water. The total analysis time per sample was about 90 min. This method improves reliability, sensitivity and sample throughput, and shortens the analysis time compared to analysis methods using off-line solid-phase extraction. 相似文献
79.
Jae Hyung Park Yong Woo Cho Yoen Ju Son Kwangmeyung Kim Hesson Chung Seo Young Jeong Kuiwon Choi Chong Rae Park Rang-Woon Park In-San Kim Ick Chan Kwon 《Colloid and polymer science》2006,284(7):763-770
An anthracycline drug, adriamycin, was chemically conjugated onto the backbone of glycol chitosan via an acid-labile cis-aconityl linkage. The physicochemical characteristics of the glycol chitosan–adriamycin (GC–ADR) conjugates were investigated by dynamic light scattering, atomic force microscopy, and fluorescence spectroscopy. The GC–ADR conjugates were capable of forming nano-sized self-aggregates in an aqueous medium, when the adriamycin content in the conjugate was in the range of 2.0–5.0 wt.%. The self-aggregates were spherical in shape, and had mean diameters of 238–304 nm, depending on the adriamycin content. The critical aggregation concentrations of the conjugates, estimated by the fluorescence quenching method, were as low as 1.0–2.5×10−2 mg/ml. The size of self-aggregates was not affected by the polymer concentration in the range from 50 to 2,000 μg/ml, and was maintained up to 8 days in phosphate-buffered saline (pH 7.4), indicating high colloidal stability. The release of adriamycin from self-aggregates was significantly dependent on the pH of the medium due to the cis-aconityl linkage; e.g., the amount of adriamycin released for 4 days was 7.3±0.3% at pH 7, whereas it was 29.3±1.9% at pH 4. The cell viability results demonstrated that free adriamycin shows more potent cytotoxicity than the conjugates, primarily attributed to the sustained release of adriamycin from self-aggregates. In conclusion, the self-aggregates, formed by GC–ADR conjugates, might be useful for the site-specific delivery of adriamycin in a sustained manner. 相似文献
80.
Park BK Jeong S Kim D Moon J Lim S Kim JS 《Journal of colloid and interface science》2007,311(2):417-424
We describe herein the synthesis of metallic copper nanoparticles in the presence of poly(vinylpyrrolidone), employed as a protecting agent, via a polyol method in ambient atmosphere. The obtained copper particles were confirmed by XRD to be crystalline copper with a face-centered cubic (fcc) structure. We observed monodisperse spherical copper nanoparticles with a diameter range 45+/-8 nm. The particle size and its distribution are controlled by varying the synthesis parameters such as the reducing agent concentration, reaction temperature, and precursor injection rate. The precursor injection rate plays an important role in controlling the size of the copper nanoparticles. On the basis of XPS and HRTEM results, we demonstrate that the surface of the copper is surrounded by amorphous CuO and that poly(vinylpyrrolidone) is chemisorbed on the copper surface. 相似文献