Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30536 (PBS)
 9,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An optimal fixation method and intensification procedure may be required in brain immunohistochemistry to obtain intense and widespread staining for a specific antigen, in cases where ordinary fixation and conventional immunohistochemistry result in only partial demonstration of the antigen. In the present study of localization of corticotropin-releasing factor immunoreactivity (CRFI) in rat brain, the importance of such intensification is shown. We describe a fixation procedure in which perfusion of rat brain with Bouin's solution is followed by a PBS wash and a further perfusion with either Zamboni's fluid or 4% paraformaldehyde in 0.1 M phosphate buffer (pH 7.4), for subsequent investigation of the detailed localization of CRFI in cerebral cortex and subcortical structures. The cobalt-glucose oxidase-diaminobenzidine (Co-GOD) intensification method has been modified to increase the sensitivity of immunostaining by reducing the concentration of glucose oxidase, which is added to the final incubation solution as a generator of hydrogen peroxide. The use of cobalt acetate instead of cobalt chloride appears to slightly suppress background staining in the Co-GOD method. Combination of the two modified procedures was applied to visualize intense and widespread CRFI in a variety of rat brain regions, including median eminence, cerebral cortex, and central amygdaloid nucleus.
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PMID:Improved fixation and cobalt-glucose oxidase-diaminobenzidine intensification for immunohistochemical demonstration of corticotropin-releasing factor in rat brain. 349 48

Sera from 98 patients were examined for antinuclear antibodies (ANA). The patient population has been previously identified clinically as having the following diseases: systemic lupus erythematosus, scleroderma, dermato or polymyositis, discoid lupus, rheumatoid arthritis, Raynaud phenomena only, undifferentiated connective tissue disease, and psoriasis. All sera samples were tested using both HEp-2 cells and rat kidney tissue as substrates and were stained with both fluorescein-conjugated antihuman antibody and glucose oxidase-conjugated antibody to human IgG. Each serum was initially tested at a screening dilution of 1:40 with PBS. Positive sera were serially diluted until an end point was observed. The number of dilutions for each specimen in all four combinations was compared mathematically using the Pearson product moment correlation. Using this method, glucose oxidase- and fluorescein-conjugated antinuclear antibody (FANA) techniques appear to have a high positive correlation (r = 0.92 kidney, r = 0.95 Hep-2) in this patient population. In our experience, the glucose oxidase technique offers comparable results to FANA and is ideally suited for the hospital laboratory, especially facilities without the benefit of a fluorescent microscope.
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PMID:A comparative study of glucose oxidase versus FITC-labeled antibody techniques for the detection of antinuclear antibodies. 643 30

A pseudo-metabolic cycle as a self-degradation system was designed: enzymatic degradation products from a polysaccharide generate oxidants which introduce a cationic charge into the polysaccharide chains, and can form a polyion complex with an anionic polysaccharide. As a component of such a system, dextran, with various degrees of nicotinamide substitution, was prepared. Its degradation by dextranase, redox reaction via glucose oxidase-catalysis, and polyion complex formation with carboxymetyl dextran (CMD) were examined. Nicotinamide-modified dextran (NA-Dex) with nine nicotinamide moieties per 100 glucose units was soluble in PBS and completely oxidized by > 100 mM H2O2. The oxidized type of NA-Dex was found to form a 1:1 complex with CMD. By the addition of dextranase, isomaltase, and glucose oxidase (GOD) to phosphate buffer solution of the reduced type of NA-Dex and CMD, the transmittance of the solution dropped, suggesting polyion complex formation via the oxidation of 1,4-dihydronicotinamide in NA-Dex by H2O2 generated from GOD-catalytic reaction. These findings are of great importance for designing a self-complex formation system aimed at biodegradable and osillative drug release.
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PMID:Self-complex formation of nicotinamide-modified dextran with carboxymethyl dextran using their degradation products. 1101 71

A simple and highly sensitive method for the detection of genomic DNA in tissue samples is described. It is based on amperometric detection of target DNA by forming an analyte/polymeric activator bilayer on a gold electrode. The biotinylated target DNA is hybridized to oligonucleotide capture probes immobilized on the gold electrode, forming the first layer. A subsequent binding of glucose oxidase-avidin conjugate to the target DNA and the introduction of a second layer of a redox polymer to the electrode, via layer-by-layer electrostatic self-assembly, allow for electrochemical detection of the catalytic oxidation current of glucose in a PBS solution. Less than 2.0 fg of rat genomic DNA, for both regulated and house-keeping genes, can be easily detected in 2.5 microl droplets. The proposed procedure shows very high specificity for genomic DNA in a RT-PCR mixture.
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PMID:Highly sensitive amperometric detection of genomic DNA in animal tissues. 1473 16

A stable suspension of carbon nanotubes (CNT) was obtained by dispersing the CNT in a solution of surfactant, such as cetyltrimethylammonium bromide (CTAB, a cationic surfactant). CNT (dispersed in the solution of 0.1% CTAB) has promotion effects on the direct electron transfer of glucose oxidase (GOx), which was immobilized onto the surface of CNT. The direct electron transfer rate of GOx was greatly enhanced after it was immobilized onto the surface of CNT. Cyclic voltammetric results showed a pair of well-defined redox peaks, which corresponded to the direct electron transfer of GOx, with a midpoint potential of about -0.466 V (vs SCE (saturated calomel electrode)) in the phosphate buffer solution (PBS, pH 6.9). The electrochemical parameters such as apparent heterogeneous electron transfer rate constant (ks) and the value of midpoint potential (E1/2) were estimated. The dependence of E1/2 on solution pH indicated that the direct electron transfer reaction of GOx is a two-electron-transfer coupled with a two-proton-transfer reaction process. The experimental results also demonstrated that the immobilized GOx retained its bioelectrocatalytic activity for the oxidation of glucose, suggesting that the electrode may find use in biosensors (for example, it may be used as a bioanode in biofuel cells). The method presented here can be easily extended to immobilize and obtain the direct electrochemistry of other redox enzymes or proteins.
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PMID:Direct electron transfer of glucose oxidase promoted by carbon nanotubes. 1530 51

A novel amperometric glucose biosensor based on the nine layers of multilayer films composed of multi-wall carbon nanotubes (MWCNTs), gold nanoparticles (GNp) and glucose oxidase (GOD) was developed for the specific detection of glucose. MWCNTs were chemically modified with the H(2)SO(4)-HNO(3) pretreatment to introduce carboxyl groups which were used to interact with the amino groups of poly(allylamine) (PAA) and cysteamine via 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide cross-linking reaction, respectively. A cleaned Pt electrode was immersed in PAA, MWCNTs, cysteamine and GNp, respectively, followed by the adsorption of GOD, assembling the one layer of multilayer films on the surface of Pt electrode (GOD/GNp/MWCNTs/Pt electrode). Repeating the above process could assemble different layers of multilayer films on the Pt electrode. PBS washing was applied at the end of each assembly deposition for dissociating the weak adsorption. Film assembling and characterization were studied by transmission electron microscopy and quartz crystal microbalance, and properties of the resulting glucose biosensors were measured by electrochemical measurements. The marked electrocatalytic activity of Pt electrode based on multilayer films toward H(2)O(2) produced during GOD enzymatic reactions with glucose permitted effective low-potential amperometric measurement of glucose. Taking the sensitivity and selectivity into consideration, the applied potential of 0.35 V versus Ag/AgCl was chosen for the oxidation detection of H(2)O(2) in this work. Among the resulting glucose biosensors, the biosensor based on nine layers of multilayer films was best. It showed a wide linear range of 0.1-10mM glucose, with a remarkable sensitivity of 2.527 microA/mM, a detection limit of 6.7 microM estimated at a signal-to-noise ratio of 3 and fast response time (within 7s). Moreover, it exhibited good reproducibility, long-term stability and the negligible interferences of ascorbic acid, uric acid and acetaminophen. The study can provide a feasible approach on developing new kinds of oxidase-based amperometric biosensors, and can be used as an illustration for constructing various hybrid structures.
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PMID:Amperometric glucose biosensor based on multilayer films via layer-by-layer self-assembly of multi-wall carbon nanotubes, gold nanoparticles and glucose oxidase on the Pt electrode. 1721 83

A novel strategy for site-specific protein immobilization via combining chip IEF with low-temperature sol-gel technology, called IEF-GEL here, in the channel of a modified poly(methyl methacrylate) (PMMA) microfluidic chip is proposed in this work. The IEF-GEL process involves firstly IEF for homogeneously dissolved protein in PBS containing alumina sol and carrier ampholyte with prearranged pH gradient, and then gelation locally for protein encapsulation. The process and feasibility of proposed IEF-GEL were investigated by EOF measurements, fluorescence microscopic photography, Raman spectrum and further demonstrated by glucose oxidase (GOx) reactors integrated with end-column electrochemical detection. Site-controllable immobilization of protein was realized in a 30 mm long microfluidic chip channel by the strategy to create a approximately 1.7 mm concentrated FITC-BSA band, which leads to great improvement of the elute peak shape, accomplished with remarkably increased sensitivity, approximately 20 times higher than that without IEF-GEL treatment to GOx reactors. The kinetic response of GOx after IEF-GEL treatment was also investigated. The proposed system holds the advantages of IEF and low-temperature sol-gel technologies, i.e. concentrating the protein to be focused and retaining the biological activity for the gel-embedded protein, thus realizes site-specific immobilization of low-concentration protein at nL volume level.
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PMID:Site-specific protein immobilization in a microfluidic chip channel via an IEF-gelation process. 1744 36

A new biosensor is prepared by cross-linking glucose oxidase (GOD) with glutaradehyde at the electrode combining Au nanoparticles (AuNP) with multi-walled carbon nanotubes (MWCNTs). Au nanoparticles-doped chitosan (CS) solution (AuNP-CS) is prepared by treating the CS solution followed by chemical reduction of Au (III) with NaBH4. MWCNTs are then dispersed in AuNP-CS solution. TEM, FT-IR, and UV-Vis show that the AuNP-CS solution is highly dispersed and stable. The synergistic effect between AuNP and CNTs of the AuNP-CNTs-CS material has been investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometric methods. The modified glassy carbon electrode (GCE) allows low-potential detection of H2O2 with high sensitivity and fast response time. With the immobilization of GOD, a biosensor has been constructed. In phosphate buffer solutions (PBS, pH 7.0), nearly free interference determination of glucose has been realized at 0.4 V(vs. Ag/AgCl/3.0 M KCI) with a wide linear range from 2.0 x 10(-5) to 1.5 x 10(-2) M and a fast response time within 5s. The biosensor has been used to determine glucose in human serum samples and the results are satisfactory.
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PMID:Electrochemical biosensor based on multi-walled carbon nanotubes and Au nanoparticles synthesized in chitosan. 1745 Sep 34

Nanofibrous glucose electrodes were fabricated by the immobilization of glucose oxidase (GOx) into an electrospun composite membrane consisting of polymethylmethacrylate (PMMA) dispersed with multiwall carbon nanotubes (MWCNTs) wrapped by a cationic polymer (poly(diallyldimethylammonium chloride) (PDDA)) and this nanofibrous electrode (NFE) is abbreviated as PMMA-MWCNT(PDDA)/GOx-NFE. The NFE was characterized for morphology and electroactivity by using electron microscopy and cyclic voltammetry, respectively. Field emission transmission electron microscopy (FETEM) image reveals the dispersion of MWCNT(PDDA) within the matrix of PMMA. Cyclic voltammetry informs that NFE is suitable for performing surface-confined electrochemical reactions. PMMA-MWCNT(PDDA)/GOx-NFE exhibits excellent electrocatalytic activity towards hydrogen peroxide (H(2)O(2)) with a pronounced oxidation current at +100 mV. Glucose is amperometrically detected at +100 mV (vs. Ag/AgCl) in 0.1M phosphate buffer solution (PBS, pH 7). The linear response for glucose detection is in the range of 20 microM to 15 mM with a detection limit of 1 microM and a shorter response time of approximately 4 s. The superior performance of PMMA-MWCNT(PDDA)/GOx-NFE is due to the wrapping of PDDA over MWCNTs that binds GOx through electrostatic interactions. As a result, an effective electron mediation is achieved. A layer of nafion is made over PMMA-MWCNT(PDDA)/GOx-NFE that significantly suppressed the electrochemical interference from ascorbic acid or uric acid. In all, PMMA-MWCNT(PDDA)/GOx-nafion-NFE has exhibited excellent properties for the sensitive determination of glucose like high selectivity, good reproducibility, remarkable stability and without interference from other co-existing electroactive species.
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PMID:A novel glucose biosensor based on immobilization of glucose oxidase into multiwall carbon nanotubes-polyelectrolyte-loaded electrospun nanofibrous membrane. 1790 78

A new strategy for fabricating a sensitivity-enhanced glucose biosensor was presented, based on multi-walled carbon nanotubes (CNT), Pt nanoparticles (PtNP) and sol-gel of chitosan (CS)/silica organic-inorganic hybrid composite. PtNP-CS solution was synthesized through the reduction of PtCl(6)(2-) by NaBH(4) at room temperature. Benefited from the amino groups of CS, a stable PtNP gel was obtained, and a CNT-PtNP-CS solution was prepared by dispersing CNT functionalized with carboxylic groups in PtNP-CS solution. The CS/silica hybrid sol-gel was produced by mixing methyltrimethoxysilane (MTOS) with the CNT-PtNP-CS solution. Then, with the immobilization of glucose oxidase (GOD) into the sol-gel, the glucose biosensor of GOD-CNT-PtNP-CS-MTOS-GCE was fabricated. The properties of resulting glucose biosensor were measured by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). In phosphate buffer solutions (PBS, pH 6.8), nearly interference free determination of glucose was realized at low applied potential of 0.1V, with a wide linear range of 1.2x10(-6) to 6.0x10(-3)M, low detection limit of 3.0x10(-7)M, high sensitivity of 2.08microA mM(-1), and a fast response time (within 5s). The results showed that the biosensor provided the high synergistic electrocatalytic action, and exhibited good reproducibility, long-term stability. Subsequently, the novel biosensor was applied for the determination of glucose in human serum sample, and good recovery was obtained (in the range of 95-104%).
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PMID:Glucose biosensors based on platinum nanoparticles-deposited carbon nanotubes in sol-gel chitosan/silica hybrid. 1837 23


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