ИСТИНА

Nowadays, the concept of the so-called ‘self-powered’ electrochemical (bio)sensors, which don’t require external energy sources, is of great interest. Such sensors are able to wake-up only in the presence of analyte and generate power sufficient for low voltage electronics. We report on the operation principle of Prussian Blue-based (bio)sensors in power generation mode. Prussian Blue (PB) is known to be the most advantageous low-potential hydrogen peroxide transducer for both hydrogen peroxide detection and oxidases-based biosensors [1]. The PB-based amperometric sensors are commonly operated at the working potential of 0.00 V (vs. Ag/AgCl/0.1 M KCl). Short-circuiting the PB-modified working electrode with the silver chloride reference electrode (through the ammeter), it is possible to adjust the working electrode potential to 0.00 V without a potentiostat. Current generated by the sensor linearly depends on hydrogen peroxide concentration in the range 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. Besides, Prussian Blue-based sensors in power generation mode retain high selectivity relatively to reductants (paracetamol, ascorbate) practically avoiding their influence on analysis. Moreover, the noise of Prussian Blue-based sensors in power generation mode is an order of magnitude lower compared to it in a conventional three-electrode regime. In turn, 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 adapted 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 with coulometric detection. Concluding, Prussian Blue-based (bio)sensors successfully operate without a potentiostat by a simple short-circuiting the working and the reference electrodes. The achieved noiseless performances of Prussian Blue based (bio)sensors in power generation mode would have a potential for low voltage read-out methods, for example for printable electronics or wearable smart devices. 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.