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3123412 
Journal Article 
Direct Electron Transfer between a Site-Specific Pyrene-Modified Laccase and Carbon Nanotube/Gold Nanoparticle Supramolecular Assemblies for Bioelectrocatalytic Dioxygen Reduction 
Lalaoui, N; Rousselot-Pailley, P; Robert, V; Mekmouche, Y; Villalonga, R; Holzinger, M; Cosnier, S; Tron, T; Le Goff, A 
2016 
ACS Catalysis
ISSN: 2155-5435 
American Chemical Society 
WASHINGTON 
6 
3 
1894-1900 
English 
WOS:000371755500060 
Strategies to maximize direct electron transfer (DET) between redox enzymes and electrodes include the oriented immobilization of enzymes onto an electroactive surface. Here, we present a strategy for achieving a controlled orientation of a fungal laccase on carbon nanotube-based electrodes. A homogeneous population of pyrene-modified laccase is obtained via the reductive amination of a unique surface accessible lysine residue engineered near the T1 copper center of the enzyme. Immobilization of the site-specific functionalized enzyme is achieved either via π-stacking of pyrene on pristine CNT electrodes or through pyrene/β-cyclodextrin host guest interactions on β-cyclodextrin-modified gold nanoparticles (β-CD-AuNPs). Contrasting with unmodified and nonspecifically modified (pyrene-NHS) laccase-electrodes, an efficient DET is obtained at these nanostructured assemblies. Modeling the direct bioelectrocatalysis of dioxygen reduction reveals a heterogeneity in ET rates on MWCNT electrodes wheras β-CD-AuNPs act as efficient electronic bridges, lowering ET rate dispersion and achieving a highly efficient reduction of O2 at low overpotential (≈80 mV) accompanied by high catalytic current densities of almost 3 mA cm-2. © 2016 American Chemical Society. 
laccase; carbon nanotubes; dioxygen reduction; electrocatalysis; biofuel cells