title: The use of Trametes versicolor laccase for the polymerization of aniline in the presence of vesicles as templates.
abstract: The enzymatic polymerization of aniline to polyaniline (PANI) with Trametes versicolor laccase (TvL) as catalyst and dioxygen (O₂) as oxidant was investigated in an aqueous medium containing unilamellar vesicles with an average diameter of about 80 nm formed from AOT (=sodium bis(2-ethylhexyl) sulfosuccinate). Compared to the same reaction carried out with horseradish peroxidase isoenzyme C (HRPC) as catalyst and hydrogen peroxide (H₂O₂) as oxidant, notable differences were found in the kinetics of the reaction, as well as in the characteristics of the PANI obtained. Under comparable optimal conditions, which are pH 3.5 for TvL/O₂ and pH 4.3 for HRPC/H₂O₂, the reaction with TvL/O₂ was much slower than with HRPC/H₂O₂, i.e. ≈27 days vs. 1 day reaction time to reach equilibrium with >90% yield at 25 °C. Although in both cases, aniline monomer coupling occurred mainly via the carbon atom in para position of aniline, UV-vis-NIR absorption and EPR measurements indicate that the reaction with TvL/O₂ yielded mainly overoxidized products (with λ(max)=730 nm). These products had a lower amount of unpaired electrons if compared with the products obtained with HRPC/H₂O₂ (with λ(max)≈1000 nm, which is characteristic for the polaron state of PANI-ES, the emeraldine salt form of PANI). Similarly to previous findings with HRPC/H₂O₂, enzyme inactivation occurred during the polymerization also in the case of TvL/O₂. Since the aqueous PANI-vesicle suspensions obtained are of high colloidal stability, they can be used directly as ink in a conventional thermal inkjet printer for printing on paper or on surface treated polyimide films. Printed PANI-ES patterns on paper changed colour from green (emeraldine salt) to blue (emeraldine base) upon exposure to ammonia gas, demonstrating the expected ammonia sensing properties.
authors.affiliation: Department of Materials, ETH Zürich, Wolfgang-Pauli-Str. 10, CH-8093 Zürich, Switzerland.
authors.forename: Katja
authors.initials: K
authors.lastname: Junker
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang-Pauli-Str. 10, CH-8093 Zürich, Switzerland.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Kissner
authors.affiliation: Laboratory for Magnetic Resonances, Rudjer Boskovic Institute, P.O. Box 180, HR-10000 Zagreb, Croatia.
authors.forename: Boris
authors.initials: B
authors.lastname: Rakvin
authors.affiliation: Department of Materials, ETH Zürich, Wolfgang-Pauli-Str. 10, CH-8093 Zürich, Switzerland.
authors.forename: Zengwei
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Department of Materials, ETH Zürich, Wolfgang-Pauli-Str. 10, CH-8093 Zürich, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Willeke
authors.affiliation: Department of Materials, ETH Zürich, Wolfgang-Pauli-Str. 10, CH-8093 Zürich, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Busato
authors.affiliation: Department of Materials, ETH Zürich, Wolfgang-Pauli-Str. 10, CH-8093 Zürich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weber
authors.affiliation: Department of Materials, ETH Zürich, Wolfgang-Pauli-Str. 10, CH-8093 Zürich, Switzerland. Electronic address: peter.walde@mat.ethz.ch.
authors.forename: Peter
authors.initials: P
authors.lastname: Walde
mesh_terms: D000641:Ammonia / Q000494:pharmacology; D000814:Aniline Compounds / Q000737:chemistry*; D055162:Biocatalysis; D003116:Color; D004578:Electron Spin Resonance Spectroscopy; D005656:Fungal Proteins / Q000378:metabolism*; D006735:Horseradish Peroxidase / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000737:chemistry; D007281:Ink; D007700:Kinetics; D042845:Laccase / Q000378:metabolism*; D015394:Molecular Structure; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology; D058105:Polymerization; D011327:Printing; D013054:Spectrophotometry, Atomic; D013056:Spectrophotometry, Ultraviolet; D019265:Spectroscopy, Near-Infrared; D055454:Trametes / Q000201:enzymology*; D053835:Unilamellar Liposomes
chemical_list: D000814:Aniline Compounds; D005656:Fungal Proteins; D016877:Oxidants; D053835:Unilamellar Liposomes; D000641:Ammonia; D006861:Hydrogen Peroxide; D042845:Laccase; D006735:Horseradish Peroxidase; D010100:Oxygen; C023650:aniline
keywords: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate); ABTS(2−); AOT; Enzyme; HRPC; Laccase; PADPA; PANI; PANI prepared with HRPC in the presence of AOT vesicles; PANI prepared with TvL in the presence of AOT vesicles; PANI-ES; PANI-HRPC-AOT; PANI-TvL-AOT; Polyaniline; Polymer; SBP; SPS; Template; Trametes versicolor laccase; TvL; Vesicle; emeraldine salt form of PANI; horseradish peroxidase isoenzyme C; p-aminodiphenylamine; polyaniline; sodium bis(2-ethylhexyl) sulfosuccinate; soybean peroxidase; sulfonated polystyrene