Hydrogen biosensors

Several other biosensors have been developed usiag this oxygen-quenched fluorescence approach. Target species iaclude ethanol [64-17-5] hydrogen peroxide [7722-84-17, H2O2, lactate, and xanthine [69-89-6] C H4N402, usiag alcohol oxidase, catalase [9001-05-2] lactate oxidase, and xanthine oxidase, respectively. An additional technique for biocatalytic biosensors iavolves the firefly chemiluminescent reaction (17) ... 

PSS-SG composite film was tested for sorption of heme proteins hemoglobin (Hb) and myoglobin (Mb). The peroxidaze activity of adsorbed proteins were studied and evaluated by optical and voltammetric methods. Mb-PSS-SG film on PG electrode was shown to be perspective for detection of dissolved oxygen and hydrogen peroxide by voltammetry with linear calibration in the range 2-30 p.M, and detection limit -1.5 p.M. Obtained composite films can be modified by different types of biological active compounds which is important for the development of sensitive elements of biosensors. 

Wang, B.Q. and Dong, S.J. (2000) Sol-gel-derived amperometric biosensor for hydrogen peroxide based on methylene green incorporated in Nafion film. Talanta, 51, 565—572. 

Zhou X., Arnold M.A., Internal enzyme fiber-optic biosensors for hydrogen peroxide and glucose, Anal. Chim. Acta 1995 304 147-156. 

Electrochemical biosensors based on detection of hydrogen peroxide at platinized electrodes were found to be more versatile allowing a decrease in detection limit down to 1 i,mol L 1 [109]. However, all biological liquids contain a variety of electrochemically easily oxidizable reductants, e.g. ascorbate, urate, bilirubin, catecholamines, etc., which are oxidized at similar potentials and dramatically affect biosensor selectivity producing parasitic anodic current [110]. 

More than 90% of commercially available enzyme-based biosensors and analytical kits contain oxidases as terminal enzymes responsible for generation of analytical signal. These enzymes catalyze oxidation of specific analyte with molecular oxygen producing hydrogen peroxide according to the reaction ... 

Among different approaches providing operation of the oxidase-based biosensors, the detection of hydrogen peroxide production was found to be the most progressive one, allowing detection of low levels of analytes [107], However, the detection of H202 has to be carried out at low potentials in order to reduce the interference of easily oxi-dizable compounds [110]. 

Application of transition metal hexacyanoferrates for development of biosensors was first announced by our group in 1994 [118]. The goal was to substitute platinum as the most commonly used hydrogen peroxide transducer for Prussian blue-modified electrode. The enzyme glucose oxidase was immobilized on the top of the transducer in the polymer (Nation) membrane. The resulting biosensor showed advantageous characteristics of both sensitivity and selectivity in the presence of commonly tested reductants, such as ascorbate and paracetamol. 

Except for Prussian blue activity in hydrogen peroxide, reduction has been shown for a number of transition metal hexacyanoferrates. The latter were cobalt [151], nickel [152], chromium [150], titanium [153], copper [154], manganese [33], and vanadium [28] hexacyanoferrates. However, as was shown in review [117], catalytic activity of the mentioned inorganic materials in H202 reduction is either very low, or is provided by impurities of Prussian blue in the material. Nevertheless, a number of biosensors based on different transition metal hexacyanoferrates have been developed. 

To make the most advantageous glucose biosensor, it is important to combine the best transduction principle with the best immobilization protocol. As mentioned, the most progressive way to couple the oxidase and the electrode reaction is a low potential detection of hydrogen peroxide. Among available H202 transducers, Prussian blue is the most advantageous one. 

Combined with the attractive performance of a Prussian blue-based hydrogen peroxide transducer, the proposed immobilization protocol provides elaboration of the most advantageous first-generation glucose biosensor concerning its sensitivity and detection limit. 

A.A. Karyakin and E.E. Karyakina, Prussian Blue-based artificial peroxidase as a transducer for hydrogen peroxide detection. Application to biosensors. Sens. Actuators, B B57, 268-273 (1999). 

P.A. Fiorito and S.I.C. de Torresi, Hybrid nickel hexacyanoferrate/polypyrrole composite as mediator for hydrogen peroxide detection and its application in oxidase-based biosensors. J. Electroanal. Chem. 581, 31 (2005). 

Y. Miao and S.N. Tan, Amperometric hydrogen peroxide biosensor with silica sol-gel/chitosan film as immobilization matrix. Anal. Chim. Acta 437, 87-93 (2001). 

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