ИСТИНА

Development of self-powered (bio)sensors, which don’t require external energy sources, is of great interest for electroanalytical applications nowadays. We report on the principle of Prussian Blue-based hydrogen peroxide sensors operation in the self-powered regime. Prussian Blue (PB), the so-called “artificial peroxidase”, is known to be the most advantageous low-potential hydrogen peroxide transducer for both the purposes of hydrogen peroxide detection itself and oxidases-based sensors operation [1]. The electrocatalyst demonstrates high activity at low potentials; therefore the PB-based amperometric sensors are commonly used at the working potential adjusted to 0 V (vs. Ag/AgCl/1 M KCl). Short-circuiting Prussian Blue-modified electrode with the silver chloride reference electrode, that is possible to set the working electrode potential about 0 V. Prussian Blue-based sensors function in galvanic mode, when the working electrode and the silver chloride reference electrode are connected through the ammeter. Generated current linearly depends on the hydrogen peroxide concentration from 1•10-7 to 1•10-3 M. The sensitivity calculated from the initial slope of the calibration graph (short-circuit current versus H2O2 concentration) in linear plots is 0.65 A•M-1•cm-2. Additionally, the maximum power of the sensor exhibits a linear dependence on hydrogen peroxide concentration with the slope of 0.038 W•M-1•cm-2. The possibility of selective hydrogen peroxide detection by its reduction in the presence of oxygen with Prussian Blue-based sensor operating in the self-powered regime was shown. Glucose and lactate Prussian Blue-based first generation biosensors, investigated in galvanic regime, demonstrate the following analytical performance. For the glucose oxidase-based biosensor the linear calibration range is prolonged over 3 orders of magnitude of glucose concentration from 2•10-6 to 2•10-3 M. The sensitivity evaluated as a slope of the initial part of the calibration graph is 0.022 A•M-1•cm-2. The lactate oxidase-based biosensor exhibits a linear detection range between 2•10-7 and 2•10-4 M lactate with a sensitivity of 0.18 A•M-1•cm-2. This is the first time (bio)sensors based on Prussian Blue and silver chloride electrode were investigated in the self-powered regime. In galvanic mode the sensors demonstrate analytical performance (i.e. sensitivity and linear calibration range) comparable to that obtained for the same sensors in three-electrode scheme and connected to potentiostat. Accordingly, these (bio)sensors are appropriate for operation without external energy sources. References: [1] Karyakin A.A., Prussian Blue and Its Analogues: Electrochemistry and Analytical Applications. Electroanalysis, 2001. 13(10): p. 813-819. Acknowledgements: Financial support through Russian Science Foundation grant # 16-13-00010 is greatly acknowledged.