Nitric oxide electrochemical sensors

Electrochemical Sensors for Nitrite and Nitric Oxide Determination 492... 

The first interest in the electroreduction of N02 or NO catalyzed by metal complexes is to model the activity of nitrite reductase enzymes.327 There is also an extensive growth in studies related to the development of metal complex-based electrochemical sensors for NO determination in biological and environmental samples 328 329 Nitrate disproportionates to nitric oxide and nitrate in aqueous solution. 

X. Zhang, Real time and in vivo monitoring of nitric oxide by electrochemical sensors - from dream to reality. Front. Biosci. 9, 3434-3446 (2004). 

A. Pailleret, J. Oni, S. Reiter, S. Isik, M. Etienne, F. Bedioui, and W. Schuhmann, In situ formation and scanning electrochemical microscopy assisted positioning of NO-sensors above human umbilical vein endothelial cells for the detection of nitric oxide release. Electrochem. Commun. 5, 847-852 (2003). 

Brovkovych et al. [38] applied the electrochemical porphyrinic sensor technique for the direct measurement of NO concentrations in the single endothelial cell. It was found that NO concentration was the highest at the cell membrane (about 1 pmoll-1) and decreased exponentially with distance from the cell, becoming undetectable at the distance of 50 pm. Now we will consider the principal reactions of nitric oxide relevant to real biological systems. 

The physiological importance of nitric oxide should also be mentioned. It plays an important role in smooth muscle relaxation, platelet inhibition, neurotransmission, immune regulation, and penile erection (Nobel Prize in 1998 for the discovery of its role in the cardiovascular system). The importance of NO in biological systems stimulated the development of electrochemical sensors and the investigation of the electrochemical behavior of that compound. 

Current research and development efforts have focused on the use of more biocompatible coatings to reduce the biological response of both intravascular and subcutaneous devices. These efforts are based on the expectation that such developments wfllbe critical to the ultimate success in developing implanted sensors that yield continuous analytical results that match closely with conventional in vitro test methods. One new approach in this direction employs novel nitric oxide (NO) release polymers to coat the surface of intravascular sensors.The potent antiplatelet activity of NO has been shown to greatly reduce the formation of thrombus on the surface of implantable electrochemical oxygen sensing catheters, and yield much more accurate continuous PO2 values in animal experiments. 

Bedioui F, Villeneuve N. Electrochemical nitric oxide sensors for biological samples-principle, selected examples and applications. Electroanalysis 2003 15 5-18. 

A library of 83 metalloporphyrins was generated by parallel synthesis.75 The substitution pattern was varied at the meso position of the porphyrines, and the central metal ions were altered (Table 14.3). To investigate the use of the members of the library as electrocatalytic material for sensitive sensors for nitric oxide (NO), a complex assay sequence was fulfilled by means of the electrochemical robotic system (Fig. 14.24). In first step, residual water was removed... 

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