Papers by Keyword: Self-Assemble

Abstract: Flowerlike nickel oxide was synthesized by a simple liquid-phase process to obtain the hydroxide precursor and then calcined to form the nickel oxide. The precursor and the nickel oxide were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG) , the scanning electron microscope(SEM) and Brunauer–Emmett–Teller-specific surface area measurement. The results indicated α-Nickel hydroxide was transferred to NiO with a cubic crystalline structure after being calcined at 450 °C; the NiO still kept the morphology of the precursors and the specific surface area of the NiO was 125.2m2/g.

Abstract: A new electrochemical immunosensor for serum myeloperoxidase (MPO) has been developed based on the self-assembly multilays of multi-walled carbon nanotubes (MWNTs), thionine (THI), gold nanoparticles (GNPs) and chitosanon (CHIT) on the glassy carbon electrode (GCE). The antibody of MPO (anti-MPO) was absorbed on the surface of GNPs monolayer. Horseradish peroxidase (HRP) was employed to block non-specific binding and amplify the response current signal. It was observed that the peak current was linear with the MPO concentration in a range of 2.5-125 µgl-1. The detection limit was 1.425 µgl-1 (S/N=3). Correlation analysis showed that this new immunosensor assay has a significant correlation with enzyme-linked immunosorbent assay (ELISA) (r=0.96, p>0.05) for 40 clinical specimens.

Abstract: α-Ni(OH)₂ with hierarchical structures were synthesized via a simple route using Ni(NO₃)₂•6H2O and urea as the starting materials. The experimental results from XRD and FT-IR showed that the samples prepared by this method had the typical α-phase and the size of samples can be control by adjusting the reaction conditions. SEM images showed many uniform flowerlike or spherelike architectures with diameters of 4-6μm consisted of dozens of nanosheets. The effects of nickel sources on the phase and morphology of the prepared samples were studied, the nickel sources had an effect on both the crystallinity and size of the prepared samples.

Abstract: This study proposes a novel sol-gel method of fabricating the two-dimensional flakes polycrystalline zinc oxide (ZnO). Apply zinc acetate dehydrate in glycerol and hydrolyzed to get the precursor zinc alkoxide particles at 160°C, and self-assemble into flakes ZnO nanostructures, and then got higer crystallinity polycrystalline ZnO after calcination for one hour at 500°C. Field-emission scanning electron microscopy (FE-SEM) was used to observe the morphology of the flakes. Its size got to a few μm². Analyze the crystal structure and crystallinity by X-ray powder diffraction (XRD). After calcination for one hour at 500°C, we can determine it is the hexagonal wurtzite structure of ZnO. And TGA/DSC to observe the loss and phase change of the solution. The Study has successfully synthesized ZnO polycrystalline flakes by sol-gel method.

Abstract: A novel DNA biosensor system on silica microspheres as solid carriers which based on the fluorescence resonance energy transfer (FRET) was presented in this work when CdTe quantum dots (QDs) were as energy donors and Au nanoparticles (AuNPs) were as energy accepters. Compared with the fluorescent intensity of CdTe QDs, the fluorescent intensity of DNA biosensors decreased extremely, which indicated that the FRET occurred between CdTe QDs and AuNPs. The biosensor system would have a certain degree recovery of fluorescence when the complementary single stranded DNA was introduced into this system. The DNA detection results indicated that this novel fluorescent DNA probe system could recognize the existence of complementary target DNA or not.

Abstract: Amphiphilic diblock copolymers based on methoxy polyethylene glycol (MePEG), 1, 6-hexanediol and maleic anhydride with different molar composition were synthesized by solution polycondensation. Self-assemble behavior of amphiphilic diblock copolymer in different solvents by dialyzing technique was discussed. The micelle morphologhy was observed by TEM. It was found that well core-shell MePEG1900/Polyester 2162 copolymer nanoparticles can be formed by self-assemble in acetone solution. In addition, the size of nanospheres measured using dynamic light scattering exhibited a narrow monodisphere size distribution and an average diameter in the ranger of less than 200nm.

Abstract: Without using any templates or surfactants, flowerlike α-nickel hydroxide (Ni(OH)₂) was successfully synthesized by homogeneous precipitation method. The prepared products were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and N₂ adsorption-desorption. The prepared Ni(OH)₂ is α-phase with specific surface area of 245.0 m²/g and shows flowerlike structure with 4-6 um in diameter.

Abstract: A novel electrochemical DNA biosensor system based on multi-walled carbon nanotubes(MWCNTs) was presented in this paper. In order to make multi-walled carbon nanotubes being perpendicularly standing on Au electrode via Au-S chemical bonding, we cut multi-walled carbon nanotubes (1.5 m) into short pipes (200-300 nm). Then, the shortened nanotubes were further modified by thiolization reaction with cysteamine (NH2CH2CH2SH). The –SH modified MWCNTs, gold nanoparticles and 5’ end –SH modified DNA (HS-DNA) as nucleotide probes were self-assembled onto the surface of Au electrode respectively. The DNA biosensors based on self-assembled MWCNTs had a higher current response compared to those based on random MWCNTs. When the target DNA concentration was 4.0×10–9 mol/L to 1.2×10-8 mol/L, the cathodic peak current of Au electrode system with the AQDS as indicator was linearly related, and the detection limit was about 6.5×10-9 mol/L. In addition, the developed DNA biosensors also had a high selectivity of hybridization detection.

Abstract: In bio-systems, nano-composites with complex micro-structures are formed by self-assembly only using low energy at room temperature. If these mechanisms of biological tissue are identified, we can possibly propose a new process to fabricate composites by mimicking tissue formation in vivo. As a bio-material, we paid attention to bio-tissue reinforced with collagen fibrils. Collagen fibrils are of baculiform; Thus the self-assembly process through liquid crystalline transition has been proposed by a French group [1]. In the present study, factors controlling liquid crystalline transition, e.g. concentration and pH, are discussed using collagen solution. When liquid crystalline phase is produced, aligned molecules exhibits optical anisotropy. This anisotropy was observed with a polarized optical microscopy (POM). By observations with POM, development of cholesteric phase in collagen solution was clarified.

Abstract: The cyclic peptides can self-assemble into β-sheet like antiparallel tubular ensembles through intermolecular hydrogen-bonding interaction. Under the self-assembling effects of the dimer subunits, various aggregate properties may alter with the change of the structure. The relationship between the property and structure of ensembles is extremely important for designing new nanostructures. Molecular mechanics (MM) and molecular dynamics (MD) were employed to investigate the structure and property of single dimer and dimer-ensemble from cyclo-[D-Phe-(1R, 3S)-γ-Acc]3. Results reveal that the single dimer cannot adsorb CHCl3 molecule into its cavity, while the two-dimer ensemble can do. It suggests that the self-assembled cyclic peptide nanotube from the dimer-ensemble may act as the transport channel of CHCl3 molecules.