ABSTRACT
Reported here is a new [Cu4I4] cluster-based coordination polymer, namely [Cu4I4(bib)2]n·n(DMF) (1, bib = 1,4-bis(imidazolyl)butane, DMF = N,N'-dimethylformamide), which was synthesized by the self-assemble reaction of CuI, bib and KI under solvothermal conditions. Remarkably, compound 1 shows promising photocatalytic performance toward to the degradation of MB solution under visible light irradiation. For the COPD treatment, the ELISA detection kit was conducted to determine the content of INF-γ released by the respiratory tract mucosal epithelial cells. In addition to this, the activation levels of the NF-κB signaling pathway were still need to be assessed by the real time RT-PCR after the compound treatment.
Subject(s)
Copper/chemistry , Copper/pharmacology , Interferon-gamma/metabolism , Pulmonary Disease, Chronic Obstructive/metabolism , Animals , Catalysis , Epithelial Cells/metabolism , Humans , Lethal Dose 50 , Mice , NF-kappa B/metabolism , Photochemical Processes , Polymers , Real-Time Polymerase Chain Reaction , Respiratory Mucosa/cytology , Respiratory Mucosa/metabolism , Signal Transduction , X-Ray DiffractionABSTRACT
The integration of Au-doped TiO(2) nanotubes with biomolecule acetylcholinesterase (AChE) yields a novel AChE-Au-TiO(2) hybrid system, which provides a new rapid and valid photoelectrochemical approach to the determination of AChE inhibition induced by endogenous neurotoxin.
Subject(s)
Acetylcholinesterase/drug effects , Cholinesterase Inhibitors/chemistry , Isoquinolines/pharmacology , Neurotoxins/pharmacology , Acetylcholinesterase/metabolism , Biosensing Techniques/methods , Gold , Kinetics , Nanotubes , Photochemistry , Semiconductors , TitaniumABSTRACT
A novel reagentless amperometric uric acid biosensor based on functionalized multi-wall carbon nanotubes (MWCNTs) with tin oxide (SnO2) nanoparticles has been developed. This was successfully applied to assay uric acid levels from an in vivo microdialysis sampling. Compared with unfunctionalized or traditional carboxylic acid (-COOH)-functionalized MWCNTs, the MWCNTs-SnO2 electrode exhibited higher electrocatalytic oxidation to uric acid. Here, MWCNTs-SnO2 may act as an efficient promoter, and the system exhibited a linear dependence on the uric acid concentration over the range from 1.0 x 10(-7) to 5.0 x 10(-4) mol L(-1). In addition, there was little ascorbic acid interference. The high sensitivity of the MWCNTs-SnO2 modified enzyme electrode enabled the monitoring of trace levels of uric acid in dialysate samples in rat striatum.
Subject(s)
Biosensing Techniques/methods , Corpus Striatum/chemistry , Nanotubes, Carbon/chemistry , Tin Compounds/chemistry , Urate Oxidase/chemistry , Uric Acid/analysis , Animals , Electrochemistry , Male , Microscopy, Electron, Transmission , Nanotubes, Carbon/ultrastructure , Rats , Rats, Sprague-Dawley , Spectroscopy, Fourier Transform InfraredABSTRACT
Glutathione (GSH) and glutathione disulfide (GSSG) are important thiols, which provide defence against oxidative stress by scavenging free radicals or causing the reduction of hydrogen peroxide. The ratio GSH/GSSG is often used as a sensitive index of oxidative stress in vivo. In this paper, a direct electrochemical method using an electrode modified with functionalized carbon nanotubes as electrochemical detector (ED) for liquid chromatography (LC) was described. The electrochemical behaviors of GSH and GSSG on this modified electrode were investigated by cyclic voltammetry and it was found that the functionalized carbon nanotubes exhibited efficiently electrocatalysis on the current responses of GSH and GSSG. In LC-ED, both of the analytes showed good and stable current responses. The detection limit of GSH was 0.2 pmol on column and that of GSSG was 1.2 pmol on column, which were low enough for the analysis of real small samples. The method was sensitive enough to detect difference in concentration of GSH and GSSG in hepatocytes from animals with and without introduction of oxidation stress by glucose or hydrogenperoxide.
Subject(s)
Chromatography, Liquid/methods , Glutathione Disulfide/analysis , Glutathione/analysis , Hepatocytes/chemistry , Animals , Diabetes Mellitus, Experimental , Electrochemistry , Electrodes , Glucose/pharmacology , Hepatocytes/drug effects , Hydrogen Peroxide/pharmacology , Mice , Nanotubes, Carbon , Oxidative Stress , Reproducibility of ResultsABSTRACT
An electrochemical method suitable for the simultaneous measurement of cerebral glucose, lactate, L-glutamate and hypoxanthine concentrations from in vivo microdialysis sampling has been successfully performed for the first time using a neutral red-doped silica (NRDS) nanoparticle-derived enzyme sensor system. These uniform NRDS nanoparticles (about 50 +/- 3 nm) were prepared by a water-in-oil (W/O) microemulsion method, and characterized by a TEM technique. The neutral red-doped interior maintained its high electron-activity, while the exterior nano-silica surface prevented the mediator from leaching out into the aqueous solution, and showed high biocompability. These nanoparticles were then mixing with the glucose oxidase (GOD), lactate oxidase (LOD), L-glutamate oxidase (L-GLOD) or xanthine oxidase (XOD), and immobilized on four glassy carbon electrodes, respectively. A thin Nafion film was coated on the enzyme layer to prevent interference from molecules such as ascorbic acid and uric acid in the dialysate. The high sensitivity of the NRDS modified enzyme electrode system enables the simultaneous monitoring of trace levels of glucose, L-glutamate, lactate and hypoxanthine in diluted dialysate samples from a rat striatum.
Subject(s)
Biosensing Techniques/instrumentation , Biosensing Techniques/methods , Glucose/analysis , Glutamic Acid/analysis , Hypoxanthine/analysis , Lactic Acid/analysis , Neostriatum/metabolism , Animals , Electrochemistry , Electrodes , Glucose/metabolism , Glutamic Acid/metabolism , Hydrogen-Ion Concentration , Hypoxanthine/metabolism , Lactic Acid/metabolism , Microscopy, Electron, Transmission , Nanotechnology , Neutral Red , Oxidoreductases/metabolism , Particle Size , Rats , Silicon Dioxide , Temperature , Time FactorsABSTRACT
A new chemically modified electrode based on the immobilization of Pt particles is fabricated and exhibits electrocatalytic oxidation for L-cysteine (L-Cys), glutathione (GSH) and penicillamine (PEN) with relatively high sensitivity. It is also adaptable to HPLC for pulsed amperometric detection (PAD) of these thiols. PAD largely improves the detection sensitivity because the alternated polarizations can effectively clean and reactivate the electrode surface. It is shown that the peak currents of L-Cys, GSH and PEN are linear to their concentrations, with the calculated detection limit of 1.1 x 10(-7), 1.8 x 10(-7) and 3.8 x 10(-7) mol L(-1), respectively (S/N = 3). The method has been successfully applied to assess the contents of L-Cys and GSH in rat striatal microdialysates. The average contents of the two analytes in rat striatum are 2.6 x 10(-6) and 2.8 x 10(-6) mol L(-1), respectively.
Subject(s)
Chromatography, High Pressure Liquid/methods , Corpus Striatum/chemistry , Electrodes , Platinum , Sulfhydryl Compounds/analysis , Animals , Cysteine/analysis , Electrochemistry , Glutathione/analysis , Oxidation-Reduction , Penicillamine/analysis , Rats , Rats, Sprague-Dawley , Reproducibility of Results , Sensitivity and Specificity , Time FactorsABSTRACT
Microdialysis sampling coupled with liquid chromatography and electrochemical detection (LC-ECD) was developed and applied to study the interaction of 6-Mercaptopurine (6-MP) with bovine serum albumin (BSA). In the LC-ECD, the multi-wall carbon nanotubes fuctionalized with carboxylic groups modified electrode (MWNT-COOH CME) was used as the working electrode for the determination of 6-MP. The results indicated that this chemically modified electrode (CME) exhibited efficiently electrocatalytic oxidation for 6-MP with relatively high sensitivity, stability and long-life. The peak currents of 6-MP were linear to its concentrations ranging from 4.0 x 10(-7) to 1.0 x 10(-4) mol l(-1) with the calculated detection limit (S/N = 3) of 2.0 x 10(-7) mol l(-1). The method had been successfully applied to assess the association constant (K) and the number of the binding sites (n) on a BSA molecular, which calculated by Scatchard equation, were 3.97 x 10(3) mol(-1) l and 1.51, respectively. This method provided a fast, sensible and simple technique for the study of drug-protein interactions.
Subject(s)
Mercaptopurine/chemistry , Proteins/chemistry , Catalysis , Chromatography, Liquid , Electrochemistry , Electrodes , Indicators and Reagents , Microdialysis , Microscopy, Electron , Nanotechnology , Oxidation-Reduction , Reproducibility of Results , Serum Albumin, Bovine/chemistryABSTRACT
In this paper, multi-wall carbon nanotubes functionalized with carboxylic groups modified electrode (MWNT-COOH CME) was fabricated. This chemically modified electrode (CME) can be used as the working electrode in the liquid chromatography for the determination of 6-mercaptopurine (6-MP). The results indicate that the CME exhibits efficiently electrocatalytic oxidation for 6-MP with relatively high sensitivity, stability and long-life. The peak currents of 6-MP are linear to its concentrations ranging from 4.0 x 10(-7) to 1.0 x 10(-4) mol l(-1) with the calculated detection limit (S/N=3) of 2.0 x 10(-7) mol l(-1). Coupled with microdialysis, the method has been successfully applied to the pharmacokinetic study of 6-MP in rabbit blood. This method provides a fast, sensible and simple technique for the pharmacokinetic study of 6-MP in vivo.
