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Master's Dissertation
DOI
10.11606/D.46.2009.tde-25062009-134317
Document
Author
Full name
Suélen Harumi Takahashi
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2009
Supervisor
Committee
Torresi, Susana Inés Córdoba de (President)
Angnes, Lúcio
Cintra, Elaine Pavini
Title in Portuguese
Sensores eletroquímicos de óxodo nítrico baseados em polímeros condutores
Keywords in Portuguese
Citocromo c
Eletroquímica
Ftalocianina tetrasulfonada de níquel
Óxido nítrico
Poli(5-amino 1-naftol)
Polímero condutor
Sensor
Sensores químicos (Desenvolvimento)
Abstract in Portuguese
Neste trabalho, foram desenvolvidos sensores eletroquímicos para a detecção amperométrica do óxido nítrico (NO) fundamentada na aplicação da ftalocianina tetrasulfonada de níquel (NiTsPc) e do poli(5-amino 1-naftol) (poli(5-NH2 1-NAP)). NiTsPc foi eletrodepositada por voltametria cíclica sobre o eletrodo de platina e caracterizada eletroquimicamente em diferentes pHs. A detecção amperométrica de NO foi bastante sensível, mas o eletrodo não apresenta seletividade suficiente, motivo pelo qual este material foi substituído pelo poli(5-NH2 1-NAP) modificado com citocromo c. A imobilização foi caracterizada por voltametria cíclica e microbalança a cristal de quartzo. As detecções amperométricas do NO foram efetuadas aplicando o potencial em -0,6 V e foi observado que a variação da corrente devido à adição do NO ocorreu somente no segundo dia após a imobilização da proteína, o que pode estar relacionado a mudanças de estrutura do citcocromo c covalentemente ligado. O poli(5-NH2 1-NAP) foi também eletropolimerizado sobre nanotubos de carbono, obtendo assim um eletrodo nanoestruturado e o citocromo c foi imobilizado nessa estrutura. Assim como para os eletrodos maciços, ele não respondeu ao NO logo após a imobilização do citocromo c, respondendo somente no segundo dia e apresentou um melhor desempenho devido a sua maior área superficial.
Title in English
Electrochemical nitric oxide sensor based on conducting polymers
Keywords in English
Conducting polymer
Cytochrome
Electrochemistry
Nickel tetrasulfonated phthalocyanine
Nitric oxide
Poly (5-amino 1-naphthol)
Sensor
Abstract in English
In this work, electrochemical sensors for nitric oxide (NO) amperometric detection were prepared. For this purpose nickel tetrasulfonated phthalocyanine (NiTsPc) and poly(5-amino 1-naphthol) (poly(5-NH2 1-NAP)) modified with cytochrome c were applied. NiTsPc was electropolymerized by cyclic voltammery at platinum electrode and were electrochemically characterized in differents pHs. NO amperometric detections were very sensitive, but the electrode does not present satisfactory selectivity, and because of this, the material was replaced by poly(5-NH2 1-NAP) modified with cytochrome c. The immobilization was characterized by cyclic voltammetry and electrochemical crystal microbalance. NO amperometric detection has been carried out by applying -0.6 V and it was observed that the current due the NO sensing was only observed at the second day after protein immobilization. This can be related with cytochrome c structural change. For nanostructuring the surface of Poly(5-NH2 1-NAP) it was electropolymerized on carbon nanotubes felt electrodes and cytochrome c was immobilized. As well as the bulk electrode, the nanostructured one did not sense NO immediately after the cytochrome c immobilization, being possible to observe current only after the second day displaying a much better performance due to its high superficial area.
 
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Publishing Date
2009-09-15
 
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