Search

• Advantageous sensitivity of the flow-through (bio)sensors upon power generation. • Up to 3 times increased signal-to-noise ratio compared to three-electrode setup. • Potentiostat-free operation, simplicity of read-out. We report on advanced Prussian Blue (PB) based flow-through (bio)sensors operated in power generation mode. The performance of such (bio)sensors in wall-jet cell is significantly improved with respect to three-electrode regime in terms of up to 1.5 times higher sensitivity probably due to the enhanced mass transport compared to it in batch cell upon stirring. Most importantly, potentiostat-free operation upon short-circuiting PB modified electrode with Ag|AgCl reference through an ammeter drastically decreases noises, which results in up to 3 times increased signal-to-noise ratio compared to conventional three-electrode flow-through systems. These findings, as well as the simplicity of the proposed approach, are encouraging for the high throughput robust sensing and open new horizons for elaboration of electrochemical analyzers. [ABSTRACT FROM AUTHOR]

We report on the microscopy-free, pure electrochemical approach for estimation of the continuity of electroactive inorganic films. Impedance spectra of the transition metal hexacyanoferrate films, electrochemically deposited under the optimized conditions, have been fitted to the Randles-type equivalent circuit, complicated by diffusion impedance with reflective boundary conditions, connected in series to the charge transfer resistance. An apparent anti-Ohmic trend is revealed in the sharp decrease of the latter with an increase in amount of the deposited inorganic film commonly presuming its thickness. Assigning charge transfer resistance to the resistance of the electrode|film interface, its observed decrease with subsequent saturation is explained in terms of an increase of the interface area until the entire electrode is covered with the inorganic film completely. Scanning electron microscopy (SEM) confirms the “anti-Ohmic” and saturation regions correspond to the partially covered and fully covered electrode surfaces, respectively. The dependence of charge transfer resistance on the amount of the deposited film thus provides an estimation of the continuity of inorganic films, which is highly important in a view of their practical applications. Except for cost efficiency, microscopy-free tools are attractive because in some cases, for instance for recessed electrodes, microscopy is hardly applicable. [ABSTRACT FROM AUTHOR]

We report on the boron-doped diamond (BDD) electrodes modified with Prussian Blue (PB) through electrochemical synthesis, open-circuit deposition, and immobilization of Prussian Blue based nanozymes. The later allowed attaining the utmost sensitivity of the H 2 O 2 sensor (≈0.14 A M−1 cm−2). Compared to conventional graphite electrodes modified with Prussian Blue, the use of BDD provided twenty times decreased oxygen reduction currents resulting in up to ten times increased signal-to-background ratio of the corresponding modified electrodes. The successful combination of exceptional diamond properties (including wide potential window for BDD electrodes) with advantageous performance characteristics of Prussian Blue sensing layers would open new horizons for H 2 O 2 detection as well as biosensors elaboration. • Electron transfer rate at the H-terminated B-doped diamond electrodes is sufficient. • Prussian Blue nanozymes immobilization provides the utmost sensitivity towards H 2 O 2. • O 2 reduction currents at the doped diamond.|Prussian Blue sensors are 20 times lower [ABSTRACT FROM AUTHOR]

Self-powered sensors are among promising candidates for wake-up device elaboration. Generally, such sensors are designed to generate superior energy output to the detriment of analytical performance. Here we report on power output of Prussian Blue (PB) based (bio)sensors retaining advanced analytical performance in power generation mode. The maximum power density is linearly proportional to analyte concentration: the slopes for hydrogen peroxide sensor and glucose biosensor are of 37 mW M−1 cm−2 and 3 mW M−1 cm−2, respectively. The cells consisted of power generating (bio)sensors are able to switch on a light-emitting diode (LED) at threshold concentration of 0.6 mM H 2 O 2 or 8 mM glucose that is suitable for naked-eye semiquantitative analysis. The presented prototype of signaling device is expected to have significant impact on the development of autonomous wake-up sensors for medical, industrial or environmental monitoring. • Prussian Blue (PB) based (bio)sensors power output is a function of analyte content. • The galvanic cells were made of PB based (bio)sensors. • The cells connected to a LED can be utilized as wake-up signaling devices. • Threshold level for sensor-based wake-up device is 0.6 mM of H 2 O 2. • Threshold level for biosensor-based wake-up device is 8 mM of glucose. [ABSTRACT FROM AUTHOR]