Effects SAM on enzyme immobilization procedures in the peroxidase based biosensor performance / Investigação dos efeitos dos procedimentos de imobilização em monocamadas auto-organizadas da enzima peroidase no desenvolvimento de um biossensor

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

In this work different immobilization procedures of HRP were investigated using as support mIatrices the self-assembled monolayers formed on gold electrodes, as well as the evaluation of the influence of these immobilization processes in the biosensor performance. For this, the used monolayers were prepared by thiols with different structures, carbon chains size and terminal groups. It was possible to have evidence that the thiol carbon chain size influences especially in the coverage monolayer and, consequently, in the efficiency of the biomolecule immobilization. From the studies carried out for the SAM characterization on the electrode surface it was possible to verify that thiols with smaller chain (n<9) trends to form monolayers with a considerable amount of defects on gold surface, that it leads to a lower coverage. However, the thiols with a higher carbon chain present a higher coverage degree, are not being good matrices for electrochemical biosensors, because it can passive the surface, making difficult the electron transfer and, consequently, the electrode sensitivity. In relation to the enzyme immobilization on gold electrodes it was verified, for different techniques, that monolayers that possess -NH2 terminal group provided the best results, probably due to the use of glutharaldeyde as ligant at the immobilization process. Analyzing the biosensor performance for the hydrogen peroxide determination was verified that SAM formed by cysteamine is more adequate for HRP immobilization, because provide the better efficiency in the enzyme immobilization associated to high sensitivity for H2O2

ASSUNTO(S)

biossensor hydrogen peroxide biossensors sam agua oxigenada hrp

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