Prussian Blue, hydrogen peroxide biosensor

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). 

Mediators such as 7,7,8,8-tetracyanoquinodimethane (TCNQ) [166], hexacyanoferrate(III) [168] and CoPC [169], which have been applied to a carbon paste or ink, are reduced by the reaction with thiocholine and then reoxidised at the carbon electrode (Fig. 23.6). A second type of mediator has involved the addition of Prussian blue (ferric hex-anocyanoferrate) into an AChE and choline oxidase (ChO) bienzyme biosensor. Prussian blue mediates the reduction of hydrogen peroxide produced by the conversion of choline to betaine by ChO [170]. 

The system was first applied for development of chemosensors for gaseous hydrogen chloride. Polyaniline, and its copolymers with different derivates of aniline were used. Then a similar approach was tested in the author s group for optimization of amperometric biosensors for glucose based on electrocatalytical detection of hydrogen peroxide. A pigment Prussian blue was used as an electrocatalyst for decomposition of this product of enzymatic oxidation of... 

Karyakin, A.A., E.E. Karyakina, and L. Gorton. 2000. Amperometric biosensor using Prussian blue-based artificial peroxidase as transducer for hydrogen peroxide. Anal. Chem. 72 1720-1723. 

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