Document Detail


An efficient non-mediated amperometric biosensor for nitrite determination.
MedLine Citation:
PMID:  20188536     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In this paper we propose the construction of a new non-mediated electrochemical biosensor for nitrite determination in complex samples. The device is based on the stable and selective cytochrome c nitrite reductase (ccNiR) from Desulfovibrio desulfuricans, which has both high turnover and heterogeneous electron transfer rates. In opposition to previous efforts making use of several redox mediators, in this work we exploited the capacity of ccNiR to display a direct electrochemical response when interacting with pyrolytic graphite (PG) surfaces. To enable the analytical application of such bioelectrode the protein was successfully incorporated within a porous silica glass made by the sol-gel process. In the presence of nitrite, the ccNiR/sol-gel/PG electrode promptly displays catalytic currents indicating that the entrapped ccNiR molecules are reduced via direct electron transfer. This result is noteworthy since the protein molecules are caged inside a non-conductive silica network, in the absence of any mediator species or electron relay. At optimal conditions, the minimum detectable concentration is 120 nM. The biosensor sensitivity is 430 mA M(-1) cm(-2) within a linear range of 0.25-50 microM, keeping a stable response up to two weeks. The analysis of nitrites in freshwaters using the method of standard addition was highly accurated.
Authors:
Célia M Silveira; Sofia P Gomes; Alberto N Araújo; M Conceição B S M Montenegro; Smilja Todorovic; Ana S Viana; Rui J C Silva; José J G Moura; M Gabriela Almeida
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-02-06
Journal Detail:
Title:  Biosensors & bioelectronics     Volume:  25     ISSN:  1873-4235     ISO Abbreviation:  Biosens Bioelectron     Publication Date:  2010 May 
Date Detail:
Created Date:  2010-04-12     Completed Date:  2010-07-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9001289     Medline TA:  Biosens Bioelectron     Country:  England    
Other Details:
Languages:  eng     Pagination:  2026-32     Citation Subset:  IM    
Copyright Information:
2010 Elsevier B.V. All rights reserved.
Affiliation:
REQUIMTE-Dept. de Química, CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
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MeSH Terms
Descriptor/Qualifier:
Biosensing Techniques*
Cytochromes a1
Cytochromes c1
Desulfovibrio desulfuricans / enzymology
Electrochemical Techniques
Enzymes, Immobilized
Fresh Water / analysis
Nitrate Reductases
Nitrites / analysis*
Silicon Dioxide
Spectrophotometry
Water Pollutants, Chemical / analysis
Chemical
Reg. No./Substance:
0/Enzymes, Immobilized; 0/Nitrites; 0/Water Pollutants, Chemical; 7631-86-9/Silicon Dioxide; 9035-35-2/Cytochromes a1; 9035-42-1/Cytochromes c1; EC 1.7.-/Nitrate Reductases; EC 1.9.6.1/nitrate reductase (cytochrome)

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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