Nitrite Biosensing Using Cytochrome C Nitrite Reductase: Towards a Disposable Strip Electrode - Biomedical Engineering Systems and Technologies - page 20

Nitrite Biosensing Using Cytochrome C Nitrite
Reductase: Towards a Disposable Strip Electrode

Cátia Correia 1 , Marcelo Rodrigues 1 , Célia M. Silveira 1 , José J.G. Moura 1 ,
Estibaliz Ochoteco 2 , Elena Jubete 2 , and M. Gabriela Almeida 1,3,*

1 REQUIMTE—Dept. de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de
Lisboa, 2829-516 Monte Caparica, Portugal
[e-mail], [e-mail],
{c.silveira,jose.moura}@fct.ul.pt
2 CIDETEC-IK4- Sensors and Photonics Unit, Parque Tecnológico de San Sebastián,
Pº Miramon, 196, 20009 Donostia - San Sebastián, Spain
{eochoteco,ejubete}@cidetec.es
3 Escola Superior de Saúde Egas Moniz, Monte de Caparica, 2829-511 Caparica, Portugal
[e-mail]

Abstract. This paper presents the results of a primary study that aims to pro-
duce miniaturized biosensing devices for nitrite analysis in clinical samples.
Following our previous works regarding the development of amperometric ni-
trite biosensors using the nitrite reducing enzyme (ccNiR) from Desulfovibrio
desulfuricans ATCC 27774, here we aimed at reducing the size of the experi-
mental set-up according to the specific needs of biomedical applications. For
this, thick-film strip electrodes made of carbon conductive inks deposited on
plastic supports were modified with the ccNiR enzyme, previously mixed with
the conductive graphite ink. Firstly, though, the electrode preparation was opti-
mized (enzyme amount, organic solvent and curing temperature). Then, the
biocompatibility of ccNiR with these harsh treatments and the analytical
performance of the modified electrodes were evaluated by cyclic voltammetry.
Finally, the carbon paste screen-printed electrodes were coated with the
ccNiR/carbon ink composite, displaying a good sensitivity (5. 3x10 -7
A.uM -1 .cm -2 ) within the linear range of 0.001 - 1.5 mM.

Keywords: Nitrite, Cytochrome c nitrite reductase, Electrochemical biosensors,
Screen printed electrodes.

1 Introduction

The detection of nitrites in physiological fluids such as plasma and urine is commonly
used for clinical diagnosis and has gained an increasing importance in biomedical
research. In fact, the nitrate-nitrite-NO pathway is emerging as an important mediator of
blood flow regulation, cell signaling, energetics and tissue responses to hypoxia
[1-3]. Most of the strategies used for analytical determination of NO 3 - and NO converge
to the quantification of NO 2 - . However, the classical protocols for nitrite assessment lack
* Corresponding author.