Biosensors superoxide

The material is presented in 17 chapters, covering topics such as trends in ion selective electrodes, advances in electrochemical immunosensors, modem glucose biosensors for diabetes management, biosensors based on nanomaterials (e.g. nanotubes or nanocrystals), biosensors for nitric oxide and superoxide, or biosensors for pesticides. 

Superoxide electrochemical sensors and biosensors principles, development and applications... 

Superoxide Electrochemical Sensors and Biosensors Principles, Development and Applications... 

L. Campanella, G. Favero, L. Persi, and M. Tomassetti, New biosensor for superoxide radical used to evidence molecules of biomedical and pharmaceutical interest having radical scavenging properties.. /. Pharrn. Biomed. Anal. 23, 69—76 (2000). 

Y. Tian, L. Mao, T. Okajima, and T. Ohsaka, Superoxide dismutase-based third-generation biosensor for superoxide anion. Anal. Chem. 74, 2428-2434 (2002). 

Our research group recently approached the problem of radical determination starting from the determination of oxygen free radicals, in particular superoxide radical, and assembling several new kinds of electrochemical sensors and biosensors suitable for this purpose [21-24]. Firstly, a voltammetric system based on the detection of reduced cytochrome c this system was also applied to develop a... 

The biosensor [1] was obtained by coupling a transducer (an ampero-metric electrode for hydrogen peroxide) with the superoxide dismutase enzyme immobilized in kappa-carrageenan gel. Sandwich the gel containing the enzyme between a cellulose acetate membrane and a dialysis membrane. Secure the whole assembly to the electrode with an O-ring (Fig. 12.1). 

Enzyme-based biosensors are very suitable for the antioxidant status evaluation, since they show excellent selectivity for biological substances and can directly determine and/or monitor antioxidant compounds in a complex media such as biological or vegetable samples without needing a prior separation step. During the course of the catalytic reaction on the electroactive substrates, the current produced at an applied potential is related to the concentration of a specific biomarker, for which the biosensor is selective. HRP-based biosensors for antioxidant status evaluation have been applied in the detection of superoxide radical [119], nitric oxide [120], glutathione [119, 121], uric acid [122, 123], and phenolic compounds [124—126],... 

Pastor I, Esquembre R, Micol V, Mallavia R, Mateo CR (2004) A ready-to-use fluorimetric biosensor for superoxide radical using superoxide dismutase and peroxidase immobilized in sol-gel glasses. Anal Biochem 334 335-343... 

This review is a survey of the research on the direct electron transfer (DET) between biomolecules and electrodes for the development of reagentless biosensors. Both the catalytic reaction of a protein or an enzyme and the coupling with further reaction have been used analytically. For better understanding and a better overview, this chapter begins with a description of electron transfer processes of redox proteins at electrodes. Then the behaviour of the relevant proteins and enzymes at electrodes is briefly characterized and the respective biosensors are described. In the last section sensors for superoxide, nitric oxide and peroxide are presented. These have been developed with several proteins and enzymes. The review is far from complete, for example, the large class of iron-sulfur proteins has hardly been touched. Here the interested reader may consult recent reviews and work cited therein [1,19]. 

For biosensors of the third generation DET to small redox proteins is of particular interest as they show interaction with reactive (oxygen) species, while enzymes in direct electric contact are suitable for reagentless metabohte measurement. Peroxidase, catalase and superoxide dismutase are also relevant to the determination of reactive oxygen species and their scavengers. 

Free radical biosensors may help to investigate the role of O2 and NO as cellular messengers by the direct, real-time measuring of free radical production directly as cell signal and in relation to stimuli to which the cell is exposed. Two types of biosensors have been developed. The first exploits the highly specific reaction of superoxide dismutase [69], while the other type is based on the cytochrome c reduction by O2 [53-55,143,147]. A further alternative uses protoporphyrin IX adsorbed to carbon material [263]. Here, however, peroxide is a strong interferent. 

ZnO nanodisks catalyzes the dismutation of 02 to 02 and H202 via a cyclic oxidation -reduction electron transfer. Therefore, the third generation biosensor for superoxide developed. Figure 12 A shows the cyclic voltammograms of ZnO/SOD electrode in the... 

Also, third-generation biosensors for superoxide anion (O ) have been developed based on superoxide dismutase (SOD) immobilised by thin silica-PVA sol-gel film on a gold electrode surface [633]. The preparation of SOD electrode is easy and simple. The uniform porous structure of the silica-PVA sol-gel matrix results in a fast response rate of immobilised SOD and is very efficient for stabilising the enzyme activity. 

Biotechnological applications of SODs and CATs concern their use in biosensors for determination of concentrations of superoxide and hydrogen peroxide, respectively [277,278]. 

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