title: Resonance scattering spectral detection of catalase activity using Au@Ag nanoparticle as probe and coupling catalase catalytic reaction with Fenton reaction.
abstract: The Au(core)Ag(shell) (Au@Ag) nanoparticles in size of 30 nm were prepared using 10 nm gold nanoparticles as seeds at 90 degrees C, and were purified by high-speed centrifugation to remove the excess trisodium citrate to obtain Au@Ag nanoprobe. In the medium of pH 4.0 acetate buffer solution--7.2 micromol/L H2O2--67 micromol/L Fe(II), Au@Ag nanoparticles exhibited a resonance scattering (RS) peak at 538 nm. Upon addition of Catalase (Ct), the system produced hydroxyl radical that oxidized the Au@Ag nanoprobe to form the AuAg nanoparticles with partly bare nanogold. Those AuAg nanoparticles aggregated to large nanoclusters that led to the RS peak wavelength red-shift and its RS peak intensity enhanced. The catalase activity (C) is linear to the enhanced RS intensity (DeltaI) in the range of 6 to 2,800 U/L, with regression equation of DeltaI = 0.168 C-0.2, the correlation coefficient of 0.9952, and detection limit of 2.8 U/L. This method was applied to the detection of serum samples, and the results were agreement with that of the spectrophotometry. A new catalytic mechanism of catalase was proposed with oxywater principle that was agreement with the results of resonance scattering spectroscopy, absorption spectrophotometry, transmission electron microscopy and laser scattering.
authors.affiliation: Guangxi Key Laboratory of Environmental Engineering, Protection and Assessment, Guangxi Normal University, Guilin 541004, P R China. ahliang@glite.edu.cn
authors.forename: Aihui
authors.initials: A
authors.lastname: Liang
authors.forename: Yueyuan
authors.initials: Y
authors.lastname: Liang
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Jiang
authors.forename: Hesheng
authors.initials: H
authors.lastname: Jiang
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods; D002374:Catalase / Q000737:chemistry*; D002384:Catalysis; D002498:Centrifugation; D017612:Gold Compounds / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D016014:Linear Models; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D012044:Regression Analysis; D018030:Silver Compounds / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D013057:Spectrum Analysis / Q000379:methods*; D013696:Temperature
chemical_list: C045076:Fenton's reagent; D017612:Gold Compounds; D018030:Silver Compounds; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron; D002374:Catalase