Colloidal Gold (colloidal + gold)

Distribution by Scientific Domains

Terms modified by Colloidal Gold

  • colloidal gold nanoparticle
  • colloidal gold particle

  • Selected Abstracts


    Separation and recovery of intact gold-virus complex by agarose electrophoresis and electroelution: Application to the purification of cowpea mosaic virus and colloidal gold complex

    ELECTROPHORESIS, Issue 17 2004
    Carissa M. Soto
    Abstract Colloidal gold has been coupled to a mutant cowpea mosaic virus (CPMV), which contains 60 cysteine residues on the surface. A purification process was developed to separate the gold-containing viral nanoblocks (VNBs) from the free gold. Agarose electrophoresis was utilized to separate the mixture followed by electroelution of the desired sample to recover the intact virus. Mobility of Au-VNB and free colloidal gold was facilitated by the addition of thioctic acid (TA). 30% of the gold-containing virus was recovered after electroelution as determined by absorbance measurements. Histogram analysis of transmission electron microscopy (TEM) images demonstrated the efficient separation of gold-containing virus from free gold. TEM and scanning electron microscopy (SEM) images indicated that the virus was recovered intact. Monodisperse spherical particles of nominal size of 45 nm were observed under SEM. [source]


    Glucosinolate Amperometric Bienzyme Biosensor Based on Carbon Nanotubes-Gold Nanoparticles Composite Electrodes

    ELECTROANALYSIS, Issue 13 2009
    V. Serafín
    Abstract A novel electrochemical biosensor design for glucosinolate determination involving bulk-incorporation of the enzymes glucose oxidase and myrosinase into a colloidal gold - multiwalled carbon nanotubes composite electrode using Teflon as binder is reported. Myrosinase catalyzes the hydrolysis of glucosinolate forming glucose, which is enzymatically oxidized. The generated hydrogen peroxide was electrochemically detected without mediator at the nanostructured composite electrode at E=+0.5,V vs. Ag/AgCl. Under the optimized conditions, the bienzyme MYR/GOx-Aucoll -MWCNT-Teflon exhibited improved analytical characteristics for the glucosinolate sinigrin with respect to a biosensor constructed without gold nanoparticles, i.e. a MYR/GOx-MWCNT-Teflon electrode, as well as with respect to other glucosinolate biosensor designs reported in the literature. The biosensor exhibits good repeatability of the amperometric measurements and good interassay reproducibility. Furthermore, the biosensor exhibited a high selectivity with respect to various potential interferents. The usefulness of the biosensor was evaluated by the determination of glucosinolate in Brussel sprout seeds. [source]


    Direct Electrochemistry of Hemoglobin Immobilized on Colloidal Gold-Hydroxyapatite Nanocomposite for Electrocatalytic Detection of Hydrogen Peroxide

    ELECTROANALYSIS, Issue 2 2009
    Juan You
    Abstract A novel nanocomposite of colloidal gold (GNPs) and hydroxyapatite nanotubes (Hap) was prepared for immobilization of a redox protein, hemoglobin (Hb), on glassy carbon electrode. The immobilized Hb showed fast direct electron transfer and excellent electrocatalytic behavior toward reduction of hydrogen peroxide. A synergic effect between GNPs and Hap for accelerating the surface electron transfer of Hb was observed, which led to a pair of redox peaks with a formal potential of (,340±2) mV at pH,7.0, and a new biosensor for hydrogen peroxide with a linear range from 0.5 to 25,,M and a limit of detection of 0.2,,M at 3,. Owing to the good biocompatibility of the nanocomposite, the biosensor exhibited good stability and acceptable reproducibility. The as-prepared nanocomposite film provided a good matrix for protein immobilization and biosensor preparation. [source]


    Separation and recovery of intact gold-virus complex by agarose electrophoresis and electroelution: Application to the purification of cowpea mosaic virus and colloidal gold complex

    ELECTROPHORESIS, Issue 17 2004
    Carissa M. Soto
    Abstract Colloidal gold has been coupled to a mutant cowpea mosaic virus (CPMV), which contains 60 cysteine residues on the surface. A purification process was developed to separate the gold-containing viral nanoblocks (VNBs) from the free gold. Agarose electrophoresis was utilized to separate the mixture followed by electroelution of the desired sample to recover the intact virus. Mobility of Au-VNB and free colloidal gold was facilitated by the addition of thioctic acid (TA). 30% of the gold-containing virus was recovered after electroelution as determined by absorbance measurements. Histogram analysis of transmission electron microscopy (TEM) images demonstrated the efficient separation of gold-containing virus from free gold. TEM and scanning electron microscopy (SEM) images indicated that the virus was recovered intact. Monodisperse spherical particles of nominal size of 45 nm were observed under SEM. [source]


    Thiol-mediated degradation of DNA adsorbed on a colloidal gold surface

    JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2003
    Shalu Mittal
    Abstract When [32P]-labeled DNA is adsorbed on colloidal gold from a 130,mmol,dm,3 solution of KH2PO4, it can subsequently be eluted with cold DNA without undergoing detectable degradation. Similarly, DNA can be incubated in solution in the presence or absence of colloidal gold with high concentrations of ,-mercaptoethanol or hexane-1-thiol without significant degradation. However, when adsorbed DNA is eluted from gold with solutions of one of the thiols, it is recovered as a mixture of mononucleotides and short oligomers. The extent of degradation increases with increasing concentration of the thiol and with increasing elution temperature. Our results emphasize that in designing protocols involving DNA adsorbed on gold surfaces, it is important to avoid allowing the DNA to come into contact with even moderate concentrations of thiols. © 2003 Society of Chemical Industry [source]


    Applications of gold cluster compounds in immunocytochemistry and correlative microscopy: comparison with colloidal gold

    JOURNAL OF MICROSCOPY, Issue 3 2000
    J. M. Robinson
    In this review, we discuss the immunocytochemical literature with respect to a comparison between conventional colloidal gold and gold cluster compounds as immunoprobes. The relative advantages and disadvantages of each of these types of particle for immunocytochemical applications are discussed. We present results from our own laboratories and those of others on the comparison of these immunoprobes in selected experimental situations. These results show the use of gold cluster compounds at both light and electron microscope levels. At the ultrastructural level, gold cluster compounds have been used in pre-embedding labelling of cultured cells, and for labelling of ultrathin cryosections and freeze-fracture preparations. Recently, fluorescently tagged gold cluster compounds have become available. Using ultrathin cryosections of human neutrophils as a model system, we demonstrate that a single immunoprobe (i.e. a fluorescently tagged gold cluster compound) is a robust probe for correlative fluorescence and electron microscopy. [source]


    Visual detection of IS6110 of Mycobacterium tuberculosis in sputum samples using a test based on colloidal gold and latex beads

    CLINICAL MICROBIOLOGY AND INFECTION, Issue 11 2006
    P. Upadhyay
    Abstract The IS6110 sequence was detected visually in sputum samples of tuberculosis patients using a bi-probe system. One of the probes was an oligonucleotide conjugated to colloidal gold particles, complementary to one end of the target strand. The other probe was an oligonucleotide conjugated to latex beads complementary to the other end of the target strand. In a reaction mix, these two probes bind to the target strand, and the latex beads are then separated by filtration. Bound latex beads have gold colloid particles at the other end of the target strand. These gold colloid particles were made visible to the naked eye by silver autometallography on the ,invisible' colloidal gold particles. The lower detection limit was 50 ng of genomic DNA of Mycobacterium tuberculosis. This new test, together with conventional PCR, was performed on DNA extracted from sputum samples of suspected tuberculosis patients. The new test was simple to perform, the results were visible to the naked eye, and the test was highly specific, as even single point mutations in the target strand sequence could be differentiated. The test could be useful in field-level laboratories because it requires no sophisticated equipment. [source]