title: TAML activator-based amperometric analytical devices as alternatives to peroxidase biosensors.
abstract: The ferric TAML catalysts [Fe{C(6)H(2)-1,2-( NCOCMe(2)NCO)(2)CMe(2)}(OH(2))](-) (1) with counterions Na(+) (a) and PPh(4)(+) (b) function similar to horseradish peroxidase in the mediated electron transfer relays, which constitute a basis for amperometric biosensors. The mediators are mono- and bis-cyclometalated Ru and Os compounds of the type of [M(C∼N)(x)(N∼N)(3-x)](m+) with x = 1 and 2 (N∼N = 2,2'-bipyridine, (-)C∼N = 2-phenylpyridinato). Cyclic voltammograms of the Ru and Os compounds are not affected by 1a though cathodic currents increase drastically in the presence of hydrogen peroxide. The reduction potentials of [M(C∼N)(x)(N∼N)(3-x)](m+) complexes vary with both the nature of metal (Ru or Os) and the number of cyclometalated ligands x (1 or 2) and therefore the potential of working electrode can be set in the range of from -0.1 to +0.6 V versus the normal hydrogen electrode (NHE). A prototype of a biosensor for H(2)O(2) is described, in which the 1b catalyst and [Os(C∼N)(2)(N∼N)](+) mediator were coimmobilized on the surface of the glassy carbon electrode using a polymeric coating.
authors.affiliation: Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh Pennsylvania 15213, United States. ryabov@andrew.cmu.edu
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Ryabov
authors.forename: Ricardo
authors.initials: R
authors.lastname: Cerón-Camacho
authors.forename: Omar
authors.initials: O
authors.lastname: Saavedra-Díaz
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Denardo
authors.forename: Anindya
authors.initials: A
authors.lastname: Ghosh
authors.forename: Ronan
authors.initials: R
authors.lastname: Le Lagadec
authors.forename: Terrence J
authors.initials: TJ
authors.lastname: Collins
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004563:Electrochemistry / Q000295:instrumentation*; D005290:Ferric Compounds / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D009992:Osmium / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; D009992:Osmium; D012428:Ruthenium; D006735:Horseradish Peroxidase