title: Lysozyme-directed synthesis of platinum nanoclusters as a mimic oxidase.
abstract: We present a simple, one-pot approach for synthesizing ultrafine platinum (Pt) nanoclusters (NCs) under alkaline conditions using lysozyme (Lys) as a template. From the analysis of the nanoclusters by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Lys VI-stabilized Pt NCs majorly consisted of Pt4 clusters. The formation of Pt NCs was confirmed using X-ray photoelectron spectroscopy and Fourier-transformed infrared spectroscopy. The maximal fluorescence of Pt NCs appears at 434 nm with a quantum yield of 0.08, a fluorescence lifetime of 3.0 ns, and excitation-dependent emission wavelength behavior. Pt NCs exhibit an intrinsic oxidase-like activity because Pt NCs can catalyze O2 oxidation of organic substrates through a four-electron reduction process. Compared with larger Pt nanoparticles, the Pt NCs produce substantially greater catalytic activity in the O2-mediated oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 3,3',5,5'-tetramethylbenzidine, and dopamine.
authors.affiliation: Department of Chemistry, National SunYat-sen University, Kaohsiung, Taiwan. tsengwl@mail.nsysu.edu.tw.
authors.forename: Cheng-Ju
authors.initials: CJ
authors.lastname: Yu
authors.forename: Tzu-Heng
authors.initials: TH
authors.lastname: Chen
authors.forename: Jhih-Yu
authors.initials: JY
authors.lastname: Jiang
authors.forename: Wei-Lung
authors.initials: WL
authors.lastname: Tseng
mesh_terms: D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D010984:Platinum / Q000737:chemistry*
chemical_list: D010984:Platinum; D010088:Oxidoreductases; D009113:Muramidase