ИСТИНА

The concept of the so-called ‘self-powered’ electrochemical (bio)sensors, which don’t require external energy sources, is of great interest nowadays. Nevertheless, ‘self-powered’ sensors are able to generate power sufficient for low-power electronics only close to the upper limit of their dynamic range. It makes them hardly applicable in complete absence of an external power supply and the most realistic application of ‘self-powered’ (bio)sensors is amperometry in the short-circuit regime. We report on the principle of Prussian Blue-based (bio)sensors operation in galvanic mode. In contrast to the reported ‘self-powered’ biosensors aiming to generate maximum power output, we propose to use the system with the smallest potential difference between electrodes. Prussian Blue (PB) is known to be the most advantageous low-potential hydrogen peroxide transducer for both the purposes of hydrogen peroxide detection and oxidases-based sensors operation [1]. The PB-based amperometric sensors are commonly used at the working potential adjusted to 0 V (vs. Ag/AgCl/0.1 M KCl). Short-circuiting the PB-modified working electrode with the silver chloride reference electrode (inc. through the ammeter), that is possible to set the working electrode potential about 0 V. Generated current linearly depends on the hydrogen peroxide concentration from 2·10 -7 to 1·10 -3 M. The sensors display advantageous performance characteristics in terms of high sensitivity – 0.65 A·M^-1 ·cm^-2 . Sensor selectivity in power generation mode exceeds two orders of magnitude allowing detection of H2O2 by its reduction in the presence of oxygen. Moreover, the noise of Prussian Blue-based sensors in power generation mode is an order of magnitude lower compared to the one in a conventional three-electrode regime even in batch cell upon stirring. In three-electrode constant potential experiments the output noise is generated by operational amplifiers enhancing noises from their inputs (inc. voltage generator and feedback control amplifier). The principle was adopted for the Prussian Blue-based glucose and lactate biosensors. Prussian Blue-based glucose sensors were shown to be applicable as test-strips for the whole blood glucose analysis. Measured blood glucose concentrations are well correlated with the values obtained by the reference method (r (Pearson’s)=0.965). Operating the developed test-system through the ammeter prevents sensors from breakdowns caused with shielding the reference electrode by a bubble. Acknowledgements: Financial support through Russian Science Foundation grant # 16-13- 00010 is greatly acknowledged. References: 1. Karyakin A.A., Prussian Blue and its analogues: Electrochemistry and analytical applications. Electroanalysis, 2001. 13(10): p. 813-819.