title: Amperometric detection of dopamine based on tyrosinase-SWNTs-Ppy composite electrode.
abstract: A novel 3-dimensional single wall carbon nanotubes (SWNTs)-polypyrrole (Ppy) composite was prepared as an electrode by chemically polymerizing polypyrrole onto SWNTs using a LiClO(4) oxidant. This composite electrode was characterized by scanning electron microscopy (SEM) and cyclic voltammetry with 1 mM [Fe(CN)(6)](-3)/[Fe(CN)(6)](-4). The SWNTs were thickly coated with chemically polymerized polypyrrole and the composite had many surface pores and crevices which could enhance mass transfer. The SWNTs-Ppy composite electrode showed a large specific surface area (30 m(2)/g) and a good reproducible current response, at about 100 times the peak current of a glassy carbon electrode (GCE). The diffusion coefficient was calculated to be 4.81x10(-6) cm(2)/s. As a biosensor application, tyrosinase was immobilized on the functionalized SWNTs and tyrosinase-SWNTs-Ppy composite was prepared in the same manner. This tyrosinase-SWNT-Ppy composite electrode was used for amperometric detection of dopamine in the presence of ascorbic acid and showed high sensitivity (467 mA/M cm(2)) and lower detection limit (5 microM) compared to previous reports.
authors.affiliation: School of Chemical and Biological Engineering, Seoul National University, Seoul, Republic of Korea.
authors.forename: Kyoungseon
authors.initials: K
authors.lastname: Min
authors.forename: Young Je
authors.initials: YJ
authors.lastname: Yoo
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D004298:Dopamine / Q000032:analysis* / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D014442:Monophenol Monooxygenase / Q000737:chemistry* / Q000378:metabolism; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D014442:Monophenol Monooxygenase; D001205:Ascorbic Acid; D004298:Dopamine