INMIBO ( EX - PROPLAME)   14614
INSTITUTO DE MICOLOGIA Y BOTANICA
Unidad Ejecutora - UE
artículos
Título:
Oxygen cathode based on a layer-by-layer self assembled laccase and osmium redox mediator
Autor/es:
SZARMOCKI R, FLEXER V, LEVIN L, FORCHIASSIN F, CALVO EJ
Revista:
ELECTROCHIMICA ACTA
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2009 vol. 54 p. 1970 - 1977
ISSN:
0013-4686
Resumen:
Abstract. Trametes trogii laccase has been studied as biocatalyst for the oxygen electro-reduction in three different
systems: (i) soluble laccase was studied in solution; (ii) an enzyme monolayer was tethered to a gold
surface by dithiobis N-succinimidyl propionate (DTSP), with a soluble osmium pyridine-bipyridine redox
mediator in both cases. The third case (iii) consisted in the sequential immobilization of laccase and the
osmium complex derivatized poly(allylamine) self-assembled layer-by-layer (LbL) on mercaptopropane
sulfonate modified gold to produce an all integrated and wired enzymatic oxygen cathode. The polycation
was the same osmium complex covalently bound to poly-(ally-lamine) backbone (PAH-Os), the polyanion
was the enzyme adsorbed from a solution of a suitable pH so that the protein carries a net negative charge.
The adsorption of laccase was studied by monitoring the mass uptake with a quartz crystal microbalance
and the oxygen reduction electrocatalysis was studied by linear scan voltammetry.
While for the three cases, oxygen electrocatalysis mediated by the osmium complex was observed,
for tethered laccase direct electron transfer in the absence of redox mediator was also apparent but no
electrocatalysis for the oxygen reduction was recorded in the absence of mediator in solution.
For the fully integrated LbL self-assembled laccase and redoxmediator (case iii) a catalytic reduction of
oxygen could be recorded at different oxygen partial pressures and different electrolyte pH. The tolerance
of the reaction to methanol and chloride was also investigated.