A Nonenzymatic Biosensor Based on Gold Electrodes Modified with Peptide Self-Assemblies for Detecting Ammonia and Urea Oxidation

Autor(es)

Bianchi, Roberta C. ^[1] ; da Silva, Emerson Rodrigo ^[1] ; Dall'Antonia, Luiz H. ^[2] ; Ferreira, Fabio Furlan ^[1] ; Alves, Wendel Andrade ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210580 Santo Andre, SP - Brazil

^[2] Univ Estadual Londrina, Ctr Ciencias Exatas, Dept Quim, BR-86057970 Londrina, PR - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Langmuir; v. 30, n. 38, p. 11464-11473, SEP 30 2014.
• Citações Web of Science: 23

Resumo

We have developed a nonenzymatic biosensor for the detection of ammonia and urea oxidation based on the deposition of peptide microstructures onto thiolated gold electrodes. FF-MNSs/MCP/Au assemblies were obtained by modifying gold substrates with 4-mercaptopyridine (MCP), followed by coating with l,l-diphenylalanine micro/nanostructures (FF-MNSs) grown in the solid-vapor phase. Benzene rings and amide groups with peptide micro/nanostructures interact with synthetic NH4(+) receptors through cation-? and hydrogen bonding. AuOH clusters on the Au surface provided the catalytic sites. The application of a predetermined concentration of analytes at the peptide interfaces activated the catalytic sites. We observed a relationship between the stability of films and the crystal structure of peptides, and we organized the FF-MNSs into an orthorhombic symmetry that was the most suitable assembly for creation of our biosensors. At 0.1 mol L(-1) NaOH, these FF-MNSs/MCP/Au electrodes have electrocatalytic properties regarding ammonia and urea oxidation that are comparable to those of enzyme-based architectures. Under optimal conditions, the electrocatalytic response is proportional to the ammonia and urea concentration in the range 0.1-1.0 mmol L(-1). The sensitivity was calculated as 2.83 and 81.3 ?A mmol L(-1) cm(-2) for ammonia and urea, respectively, at +0.40 V (vs SCE). Our detection method is easy to follow, does not require a mediator or enzyme, and has strong potential for detecting urea via nonenzymatic routes (AU)

• Processo FAPESP: 08/10537-3 - Estudo de polimorfos de fármacos cristalinos através da difração de raios X por policristais e do método de Rietveld
• Beneficiário: Fabio Furlan Ferreira
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 13/12997-0 - Auto-organização hierárquica de peptídeos anfifílicos: mecanismos fundamentais e potenciais aplicações
• Beneficiário: Wendel Andrade Alves
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/12674-6 - Investigações estruturais em sistemas-modelo à base de peptídeos anfifílicos
• Beneficiário: Emerson Rodrigo da Silva
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 11/05374-0 - Compostos peptídicos nanoestruturados funcionalizados com polianilina para direta imobilização da urease
• Beneficiário: Roberta Martins da Costa Bianchi
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 08/57805-2 - Instituto de Bioanalítica
• Beneficiário: Lauro Tatsuo Kubota
• Modalidade de apoio: Auxílio à Pesquisa - Temático