Microelectrode array in mixed alkanethiol self-assembled monolayers: Electrochemical studies

Autor(es)

Cancino, Juliana ^[1] ; Machado, Sergio A. S. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Nanomed & Nanotoxicol Lab, Phys Inst Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Grp Mat Eletroquim & Metodos Eletroanalit, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Electrochimica Acta; v. 72, p. 108-113, JUN 30 2012.
• Citações Web of Science: 14

Resumo

We report an efficient alternative to obtain recessed microelectrodes device on gold electrode surface, in which mixed self-assembled monolayer of long and short carbon alkanethiol chains was used for this purpose. Development of the modified electrodes included the chemical adsorption of 11-mercaptoundecanoic acid and 2-mercaptoethanol solution, as well as their mixtures, on gold surface, resulting in the final mixed self-assembled monolayer configuration. For comparison, the electrochemical performance of self-assembled monolayer of 11-mercaptoundecanoic acid. 3-mercaptopropionic acid, 4-mercapto-1-butanol and 6-mercapto-1-hexanol modified electrodes was also investigated. It was verified that, in the mixed self-assembled monolayer, the 11-mercaptoundecanoic acid acts as a barrier for electron transfer while the short alkanethiol chair is deposited in an island-like shape through which electrons can be freely transferred to ions in solution, allowing electrochemical reactions to occur. The performance of the modified electrodes toward microelectrode behavior was investigated via cyclic voltammetry and electrochemical impedance spectroscopy measurements using {[}Fe(CN)(6)](3-/4-) redox couple as a probe. In this case, sigmoidal voltammetric responses were obtained, very similar to those observed for microelectrodes. Such behavior reinforces the proposition of electron transfer through the short alkanethiol chain layer and surface blockage by the long chain one. Electrochemical impedance results allowed calculated the mean radius value of each microelectrode disks of 3.8 mu m with about 22 mu m interval between them. The microelectrode environment provided by the mixed self-assembled monolayer can be conveniently used to provide an efficient catalytic conversion in biosensing applications. (C) 2012 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 07/59201-4 - Eletrodos modificados com camadas auto-organizadas para a imobilizacao de enzimas.
• Beneficiário: Sergio Antonio Spinola Machado
• Modalidade de apoio: Auxílio à Pesquisa - Regular