Evidence of short-range electron transfer of a redox enzyme on graphene oxide electrodes

Autor(es)

Martins, Marccus V. A. ^[1] ; Pereira, Andressa R. ^[2] ; Luz, Roberto A. S. ^[1] ; Lost, Rodrigo M. ^[2] ; Crespitho, Frank N. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210170 Santo Andre, SP - Brazil

^[2] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 16, n. 33, p. 17426-17436, SEP 7 2014.
• Citações Web of Science: 23

Resumo

Direct electron transfer (DET) between redox enzymes and electrode surfaces is of growing interest and an important strategy in the development of biofuel cells and biosensors. Among the nanomaterials utilized at electrode/enzyme interfaces to enhance the electronic communication, graphene oxide (GO) has been identified as a highly promising candidate. It is postulated that GO layers decrease the distance between the flavin cofactor (FAD/FADH(2)) of the glucose oxidase enzyme (GOx) and the electrode surface, though experimental evidence concerning the distance dependence of the rate constant for heterogeneous electron-transfer (k(het)) has not yet been observed. In this work, we report the experimentally observed DET of the GOx enzyme adsorbed on flexible carbon fiber (FCF) electrodes modified with GO (FCF-GO), where the k(het) between GO and electroactive GOx has been measured at a structurally well-defined interface. The curves obtained from the Marcus theory were used to obtain k(het), by using the model proposed by Chidsey. In agreement with experimental data, this model proved to be useful to systematically probe the dependence of electron transfer rates on distance, in order to provide an empirical basis to understand the origin of interfacial DET between GO and GOx. We also demonstrate that the presence of GO at the enzyme/electrode interface diminishes the activation energy by decreasing the distance between the electrode surface and FAD/FADH(2). (AU)

• Processo FAPESP: 13/04663-4 - Bioeletrodos enzimáticos aplicados em biocélulas a combustível: simulação e experimental
• Beneficiário: Frank Nelson Crespilho
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 11/01541-0 - Desenvolvimento de bioanodos constituídos por glicose oxidase e frutose desidrogenase e suas formas recombinantes para aplicação em protótipos de biocélulas a combustível enzimáticas: geração de energia a partir da biomassa (cana-de-açúcar)
• Beneficiário: Frank Nelson Crespilho
• Modalidade de apoio: Auxílio à Pesquisa - Regular