ИСТИНА

Prussian Blue (PB) is known to be the most advantageous low-potential hydrogen peroxide transducer, which can be used both for the detection of hydrogen peroxide and as a platform in the design of oxidase-based biosensors. In neutral aqueous media, favourable for applications in life science as well as for biosensors, PB is 1000 times more active in hydrogen peroxide reduction and oxidation providing three orders of magnitude improved sensitivity of the resulting (bio)sensors and 1000 times more selective allowing hydrogen peroxide detection by its reduction in the presence of oxygen1). Continuous monitoring of metabolites, for example, glucose and lactate in clinical diagnostics and, especially, in sports medicine is of great interest nowadays. Therefore corresponding biosensors should possess high operational stability. There are two basic ways to improve its stability: development of novel enzyme immobilization protocol or selection optimal transducer. Earlier we developed optimal protocols for oxidases immobilization onto the PB modified electrodes2,3). The only disadvantage of PB is its inherent instability. Among a number of approaches used for stabilization of PB, the building of multilayers with non-iron hexacyanoferrates isostructural to PB seems to be the most progressive. We report here, that the iron-nickel hexacyanoferrate bilayer characterized by high catalytic activity (close to activity of pure PB) as well as high operational stability was obtained. To create biosensors suspending lactate / glucose oxidase aqueous solution in isopropanol containing γ-aminopropyltriethoxysilane / Nafion analogue was deposited onto the top of iron-nickel hexacyanoferrate modified electrode.As it is seen from table, operational stability of biosensors was ≈ 2 times improved. The dynamic range of PB-Ni hexacyanoferrate based biosensors is similar to it for conventional PB based ones, which allows using the former for similar purposes drastically improving their performance characteristics. Thus, stabilized PB based glucose and lactate biosensors can be used for continuous monitoring lactate and glucose in various biological liquids.References 1) Karyakin A. A. Electroanalysis, 2001, 13, 813-819. 2) Karyakin A. A., Kotel'nikova E. A., Lukachova L. V., Karyakina E. E., Wang J. Anal. Chem., 2002, 74, 1597-1603. 3) Yashina E. I., Borisova A. V., Karyakina E. E., Shchegolikhina O. I., Vagin M. Y., Sakharov D. A., Tonevitsky A. G., Karyakin A. A., Anal. Chem., 2010, 82, 1601-1604. 4) Karpova E. V., Karyakina E. E., Karyakin A. A. JES, 2017, 164 (5), B3056–B3058.