Ferricyanide Ion Research Articles

Interaction between intrinsically disordered proteins Praja1 and α-synuclein on gold electrodes

Abstract The behavior of Praja1 (PJA1) interacting with alpha-synuclein (α-Syn) on gold electrode was investigated using electrochemical methods, where both PJA1 and α-Syn are intrinsically disordered proteins. From the electrode reaction of ferricyanide ions added as a probe, it was suggested that PJA1 interacts with α-Syn even in its adsorbed state on gold substrate and that the state of PJA1 on gold electrode can be classified into four categories depending on the α-Syn concentration.

Kinetic study on bimolecular photochemical quenching of tris(2,2'-bipyridyl)ruthenium(II) complex in water-ethylene glycol binary media.

The bimolecular photochemical quenching of the tris(2,2'-bipyridyl)ruthenium (II) complex by ferricyanide ions in water-ethylene glycol binary media was investigated using a spectrophotometric approach, as previously reported by our research group. Time-resolved spectroscopy revealed that dynamic photochemical quenching occurred via a diffusion-dominated pathway. The static quenching process was found to occur significantly when the concentration of ethylene glycol was greater than 40 wt%. The analysis of the Stern-Volmer plots revealed that the emitters and quenchers tended to show ionic associations in water-ethylene glycol compared to our previous results with a water-glycerol binary solvent system. This is attributed to hydrophobicity, which is consistent with pioneering works that report that the addition of ethylene glycol to pure water forms hydrophobic regions, leading to dehydration of the complex ions.

Additive manufactured metal lattice structures used as flow-through electrodes in a filter-press electrochemical reactor

This study deals with the electrochemical and hydraulic performances of additive manufactured metal periodic lattice structure electrodes. These electrodes are fabricated by Laser Powder Bed Fusion (LPBF) from the titanium alloy TA6V and two structures have been studied: diagonal and octet-truss. They are integrated, as flow-through electrodes, in an electrochemical filter-press reactor. Current–potential curves are experimentally obtained by linear sweep voltammetry when feeding the reactor with a ferricyanide solution. From the measurement of the limiting current of ferricyanide ions reduction, the volumetric mass transfer coefficient kAe is determined for several flow rates. Numerical simulations of fluid flow and mass transfer in these structures are also performed. Results show high values of kAe for these structures (competing with carbon felt electrodes) while maintaining a high permeability (low flow resistance). The surface roughness, inherent to the additive manufacturing process, is found to induce a low (≲10%) enhancement of mass transfer despite the roughness size (Ra in the range 10-20μm) is close to the average thickness of the diffusion layer (for the investigated fluid velocities). As a result, these electrode structures show promising potential to be used in intensified electrochemical reactors by being further optimized to find the optimal internal dimensions that maximize mass transfer while limiting flow resistance.

Flow Battery Driven by a Difference in Solvation Toward the Effective Use of Diverse Forms of Energy

Further utilization of renewable and waste energy is a crucial factor for the decarbonization of energy systems. We have recently proposed a concept of an electrochemical cell using a difference in solvation [1]. Figure 1 shows a flow battery derived from the concept, called solvation difference flow battery (SDFB). Although the anolyte and catholyte employ the same redox species, the ratio in the binary solvent is different. In this situation, the difference in the solvation states of the redox couple between the anolyte and catholyte generates the electromotive force. As shown in Fig.1, ferro-/ferricyanide ions (Fe(CN)6 4-/3-) are employed as the redox species in both anolyte and catholyte. The electrolyte solvent is composed of dimethyl sulfoxide (DMSO) and water. The anolyte is water-lean and the catholyte is water-rich, respectively. After discharging, the SDFB can be charged by transferring the water from the water-rich side (spent catholyte) to the water-lean side (spent anolyte), which means that the transfer of water regenerates the spent anolyte as the fresh catholyte, and vice versa. It is noteworthy that transferring the solvent can be performed by utilizing diverse forms of energy, such as thermal and mechanical energy as an energy input for the charge.We previously reported that the combination of DMSO and water allows a large cell voltage [1] owing to the significant difference in the electron acceptability between the solvents [2, 3]. However, the cell performance and its rate-determining processes have not been fully understood. In this work, we investigated the current-voltage (IV) characteristic of the DMSO/water-based SDFB using the prototype flow cell.For the electrolyte, tetraethyl ammonium salts of Fe(CN)6 4-/3- and tetraethyl ammonium bromide as redox species and a supporting electrolyte, respectively, were dissolved in DMSO and pure water was added to the solution to adjust the molar ratio of DMSO and water. The molar ratios of water in the anolyte and catholyte were kept at 0.1 and 0.8, respectively. The carbon paper electrodes were employed for both anode and cathode of the flow cell. The anion exchange membrane (AEM) was used as a separator. Therefore, bromide ion works as a carrier ion in this flow cell. As a result, the maximum power density of 4.5 W m-2 was observed for the prototype SDFB.We also conducted Electrochemical impedance spectroscopy (EIS) for the flow cell applying a symmetric electrolyte system to investigate the crucial factor that limits the power density. Both water-lean and water-rich electrolytes were prepared for the EIS to investigate the effect of the solvent composition. Moreover, in addition to the AEM used in the investigation of IV characteristics, porous filter was also used as the flow cell's separator to clarify the total cell resistance factor. The Nyquist plots represented the large cell resistance when the AEM and water-lean electrolyte was applied. On the other hand, the cell resistance was small when the porous filter was utilized as the separator, regardless of the molar ratio of water in the electrolyte. The Nyquist plots also indicated that the reaction resistance was relatively small.Therefore, these results indicate that the large AEM resistance influences the total cell resistance in the water-lean electrolyte (anolyte). These results imply that it should be a practical approach to develop an alternative SDFB electrolyte that can avoid the significant AEM resistance for increasing the power density. From the viewpoint of the cell assembly, the exploration of alternative separators that exhibits both high ion conductivity in the water-lean electrolyte and low permeability of solvent molecules should drastically improve the power density of the DMSO/water-based SDFB.

Ultrafast Nucleation Reverses Dissolution of Transition Metal Ions for Robust Aqueous Batteries.

The dissolution of transition metal ions causes the notorious peeling of active substances and attenuates electrochemical capacity. Frustrated by the ceaseless task of pushing a boulder up a mountain, Sisyphus of the Greek myth yearned for a treasure to be unearthed that could bolster his efforts. Inspirationally, by using ferricyanide ions (Fe(CN)63-) in an electrolyte as a driving force and taking advantage of the fast nucleation rate of copper hexacyanoferrate (CuHCF), we successfully reversed the dissolution of Fe and Cu ions that typically occurs during cycling. The capacity retention increased from 5.7% to 99.4% at 0.5 A g-1 after 10,000 cycles, and extreme stability of 99.8% at 1 A g-1 after 40,000 cycles was achieved. Fe(CN)63- enables atom-by-atom substitution during the electrochemical process, enhancing conductivity and reducing volume change. Moreover, we demonstrate that this approach is applicable to various aqueous batteries (i.e., NH4+, Li+, Na+, K+, Mg2+, Ca2+, and Al3+).

On the chemistry of the Archetti test for caffeine and uric acid

The Archetti colour test is based on the reduction of ferricyanide ions to ferrocyanide, giving Prussian blue. However, the oxidation sequence of reactions that take in the organic molecule has not been described. Some electroanalytical experiments on the oxidation of caffeine have been done but the results have not been adequately interpreted. Besides, they are incomplete since only the redox reactions can be detected, but not the isomerization and degradation path. In the present communication the complete oxidation route of caffeine is given, as well as the electron flow in each step. It involves hydration of the imino group and oxidation to 1,3,7-trimethyl-uric acid, formation of radical ion at C-9, interaction with the C─C double bond, aziridinone formation, carbon monoxide extrusion, carbonium ion neutralization, imine acidolysis, isomerization of carbinolamine and hydrolysis to the end products.

In Situ Prussian Blue-Electrocatalyst Formation on Intrinsic Iron-Containing Pristine-MWCNT as a Template and Its EQCM and SECM Interrogations and Batch Injection Analysis of Hydrogen Peroxide

Herein, we report in-situ electrochemical derivatization of the intrinsic iron species in a pristine-multiwalled carbon nanotube (MWCNT) as Prussian blue (PB) modified MWCNT hybrid (MWCNT@PB) using a dilute solution of ferricyanide as a derivatization agent in pH 2 HCl-KCl solution. The PB hybrid system showed a defined redox peak at an apparent standard electrode potential, Eo’ = 0.18 V vs Ag/AgCl with an excess surface value, 1.71 × 10−10 mol cm−2. A discreet EQCM study on the electrochemical preparation of MWCNT@PB using MWCNT and ferricyanide precursors reveal the specific stripping of iron species and uptake of iron species, potassium and ferricyanide ions upon the electrochemical preparation condition. In-situ imaging of MWCNT@PB was carried out using SECM with ferricyanide as a redox mediator under a feedback-current mode. It has been identified that a mixed-potential based electrochemical reaction involving oxidative stripping of iron to iron ion species (step-1) coupled with reduction of ferricyanide to ferrocyanide (step-2) followed by a chemical interaction between the iron ion and ferricyanide (step-3) have occurred for the overall formation of MWCNT@PB hybrid. Electrocatalytic and electroanalytical performance of the MWCNT@PB hybrid towards H2O2 reduction and sensing were demonstrated by performing cyclic voltammetric, amperometric i-t and batch injection analysis.

Experimental and Molecular Dynamic Modeling Studies of Electrospun Carbon Fiber Electrode Performance Enhancement by Potassium Ferricyanide Addition

In this work, we convert coal extraction waste into functional carbon fiber electrodes. Detailed experimental and modeling studies reveal the importance of surface properties and dramatic increase (162%) in capacitance with adding small amount of 0.01 M K3Fe(CN)6 to 6 M KOH (referred to as mixed electrolyte). Molecular dynamics (MD) modeling reveals that ferricyanide ions in the mixed electrolyte contributed to the increase of both pseudocapacitance and electric double layer capacitance. With the mixed electrolyte, a symmetric supercapacitor (SSC) using coal-derived carbon fiber mat electrodes can deliver energy density as high as16.8 Wh kg–1 at a power density of 362.2 W kg–1, with excellent cycling stability (∼95.83% at 10,000 cycles). This study provides an insightful perspective on the strategic efforts of nonthermal usage of coal as we transition to renewable energy economy. Additionally, the mixed electrolyte effect and MD modeling results shed light on carbon electrodes from biomass, such as lignin, for various electrochemical energy devices.

In situ formed and switchable enzymatic activity of BiOBr under light stimulation for homogeneous and label-free bioassay

A new concept to construct photoresponsive nanozyme through the in situ deposition of electron transporting material (ETM) on BiOBr nanoplates was proposed. That was, the spontaneous coordination of ferricyanide ions (i.e., [Fe(CN)6]3-) onto the surface of BiOBr formed electron transporting material (ETM), which efficiently prevented electron–hole recombination and led to efficient enzyme mimicking activity under light stimuli. Moreover, the formation of the photoresponsive nanozyme was regulated by pyrophosphate ions (PPi) due to the competitive coordination of PPi with [Fe(CN)6]3- onto the surface of BiOBr. This phenomenon allowed the construction of an engineerable photoresponsive nanozyme that was coupled with the rolling circle amplification (RCA) reaction to elucidate a novel bioassay for chloramphenicol (CAP, taken as a model analyte). The developed bioassay manifested the merits of label-free, immobilization-free and with efficiently amplified signal. Quantitative analysis of CAP in a wide linear range from 0.05 to 100 nM with the detection limit of 0.015 nM was realized, which endowed the methodology with sufficiently high sensitivity. It is expected to be a powerful signal probe in bioanalytical field by virtue of its switchable and fascinating visible-light-induced enzyme mimicking activity.

EVALUATION OF THE ANTIOXIDANT PROPERTIES AND GC-MSD ANALYSIS OF COMMERCIAL ESSENTIAL OILS FROM PLANTS OF THE Lamiaceae FAMILY

Plants of the Lamiaceae family have been used for thousands of years in cooking, as well as phyto- and aromatherapy. Their essential oils are characterized by high antioxidant and other types of biological activities. In our study, the phytochemical profile and quantification of the essential oil components of thyme, marjoram, and sage were analyzed by gas chromatography with mass-spectrometric detection (GC-MSD). The antioxidant properties of the samples were evaluated using total antioxidant parameters (total antioxidant capacity (TAC), ferric reducing power (FRP), antioxidant activity (AOA) towards 2,2-diphenyl-1-picrylhydrazyl (DPPH•), and total phenolics by Folin–Ciocalteu method). The obtained FRP was 46–321-fold lower than TAC, which is consistent with the contents of phenolics identified in the samples. Terpenes, isopropylmethylphenols, and eugenol turned out to be the major components of all essential oils and determined their TAC and AOA. The Folin–Ciocalteu method was applicable to the thyme essential oil only. Its FRP, which is based on the reaction of phenolic antioxidants with electrogenerated ferricyanide ions, agreed well with the total phenolic contents (329 ± 17 and 334 ± 15 mg of carvacrol per mL, respectively). The thyme essential oil had the highest antioxidant parameters, while sage showed the weakest antioxidant properties. Positive correlations (r = 0.8846–0.9964) of the antioxidant parameters were obtained.

A novel method for Ion Exchange Capacity characterization applied to Anion Exchange Membranes for Water Electrolysers

Hydrogen production from water electrolysis, hydrogen fuel cells and redox flow batteries are the right approach for the renewable energy sector because the electricity generated by solar, wind, photovoltaic, hydroelectric can be managed with a carbon-free approach. These technologies all have in common one fundamental component: the membrane. Different types of membranes have been developed for both cationic and anionic exchange, and recently, research activity focalized on improving their performances is very fervent. One fundamental characteristic of a membrane is its Ion Exchange Capacity (IEC), i.e. the density of charged functionalizing groups. Within our research project NEMESI, funded by EU-PNRR (ID: RSH2B_000002), and dedicated to Anion Exchange Membrane Water Electrolysis, we studied and validated a novel alternative method to measure IEC. The present titration methods have limitations for the need of dedicated hardware or qualitative inspection of their color-turning endpoint. The proposed method, based on the redox titration of potassium ferricyanide with ascorbic acid, allows a quantitative and independent assessment based on both potentiometric and spectrophotometric measurements, along with the usually adopted visual observation, as the yellow-colored ferricyanide is reduced to colorless ferrocyanide. Moreover, if compared to the classical Mohr titration with silver nitrate, the new method can be carried out at variable ferricyanide concentrations during the addition of the ascorbic acid, so a complete curve of the redox reaction can be constructed: the initial ferricyanide ion load of the membrane (IEC) can thus be derived in a more precise way than with a single-point evaluation. Only one Ag/AgCl reference electrode and a platinum working electrode are required without any power supply/potentiostat. The proposed method was validated using Anion Exchange Membranes with known IEC.

Evaluation of Antioxidant Activity of Thesium viride Hill (Santalaceae)

Background: Thesium viride is commonly called 'Huntu' in Hausa. It is a hemi-parasite subshrub from the family Santalaceae. The aerial part of the plant is used in the treatment of jaundice, liver enlargement, splenomegaly and ulcers. Despite its uses in diseases that may be attributed to free radical there was no studies to evaluate of the antioxidant activity. The study aimed to evaluate the antioxidant activity of 70% aqueous ethanol extract of T. viride (AETV) and its fractions; ethyl acetate (ETV), butanol (BTV) and aqueous (ATV). Methods: The plant was collected at Karaukarau, Giwa Local Government Area of Kaduna State and was identified and authenticated at the Herbarium Unit of the Department of Biological Sciences, Ahmadu Bello University. The aerial part of the plant collected was air dried under the shade and powdered. It was macerated with 70% aqueous ethanol and a portion of the extract was successively fractionated using ethyl acetate, n-butanol and water. The free radical scavenging activity of the 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH), reducing power of ferricyanide ion (FRAP), total antioxidant capacity (TAC) of the phosphomolybdenum method and the estimation of total phenolics (TP) and total flavonoids (TF) contents have been determined for all studied extracts/fractions by spectrophotometric methods. Results: Both TP (155.47 mg gallic acid equivalent [GAE]/g ± 10.32 mg GAE/g) and TF contents (103.29 mg quercetin equivalent [QE]/g ± 4.43 mg QE/g) were determined to be highest in ETV. The DPPH free radical, FRAP assays and TAC showed a concentration dependent activity with ETV exhibited the highest antioxidant capacity as determined by all the methods. Using Pearson'scorrelation analysis between the values of FRAP-TAC (R2 = -0.91) at p < 0.05 indicates the viability of the two models for evaluating antioxidants from T. viride. Conclusion: The antioxidant evaluation based on the models used in this study revealed that AETV and especially the ETV possess antioxidant activity. 

Constant-Current Coulometry with Electrogenerated Titrants as a Novel Tool for the Essential Oils Screening Using Total Antioxidant Parameters.

Essential oils are widely used in aromatherapy, medicine, and food industries due to a wide spectrum of bioactivity. Their antioxidant properties can be considered as markers of therapeutic effect and quality. Constant–current coulometry with electrogenerated titrants has been successfully applied for these purposes for the first time. Fifteen types of essential oils from various plant materials have been studied. Their composition has been identified by gas chromatography with mass-spectrometric detection (GC-MS). The reactivity of individual antioxidants of essential oils towards electrogenerated titrants (bromine and ferricyanide ions) has been estimated. Total antioxidant parameters, in particular total antioxidant capacity (TAC) and ferric reducing power (FRP) based on the reactions of essential oil antioxidants with electrogenerated bromine and ferricyanide ions, respectively, have been evaluated. Positive correlations (r = 0.7051–0.9558) with common antioxidant tests (antioxidant activity by reaction with 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and total phenolic content by the Folin–Ciocalteu method) have been obtained. Coulometric approaches overcome the limitations of spectrophotometry and are applicable to a wider range of essential oils.

Determination of polyanion utilizing a promoted glucose oxidase enzymatic reaction by ε-poly-L-lysine.

In this paper, a sensitive determination method for polyanion using a glucose oxidase (GOx) enzymatic reaction with ferricyanide ion is described. We previously reported that the GOx enzymatic reaction was significantly promoted by a cationic polymer of ε-poly-L-lysine (εPL), and the enzymatic reaction could be utilized for the determination of εPL. Generally, polycation stoichiometrically forms polyion complex with polyanion. Thus, it is expected that the promotion effect of εPL on the enzymatic reaction is interfered by polyanion, and the enzymatic reaction is also applicable to the determination of polyanion. Predictably, the promotion effect of εPL was stoichiometrically interfered by polyanions, such as polyvinyl sulfate and polyacrylate, and the interference effect allowed for the determination of the polyanions. The detection limit of polyanion was estimated to be ~ 0.3 μeq L-1. As a preliminary application, the proposed method was applied to the determination of anionic polymer of heparin in a human plasma.

Removal of bromothymol blue dye by the oxidation method using KMnO4: Accelerating the oxidation reaction by Ru (III) catalyst

Oxidation is the preferred method that used for the removal of colored toxic dyes from wastewater. Various oxidizing agents such as permanganate ion, chromate ion, ferricyanide ion have been studied kinetically to remove these colored dyes from water. In compared to the other oxidizing agents, potassium permanganate is inexpensive, water-soluble, eco-friendly oxidant, and it can be used in acid, alkaline, and neutral conditions. In addition, it has been widely used for treatment of pollutants in drinking water and waste-water applications for over 50 years. In this work, the kinetics of bromothymol blue (BTB) oxidation by KMnO4 were investigated using a conventional spectrophotometer in neutral solutions. The oxidation reaction rates were accelerated to notable rates by using of Ru (III) as a homogeneous catalyst. The pseudo-1st - order model showed a 1st order in terms of both reactant's concentration, and 2nd overall reaction. The kinetic data indicated the founding of a 1:1 intermediate species with the intervention of free radicals into the reaction mechanism. At the reaction conditions of [BTB]=1 × 10–5, [MnO4–] = 4 × 10–4 mol dm–3, and 25 °C, the pseudo-first order rate constant values were calculated to be 1.13×10–4 s–1 without Ru (III) and 1.66×10–4 using Ru(III) as a catalyst (4 × 10–4 mol dm–3). Considering the kinetic results, a putative the mechanism of the reaction in the stated redox reaction is postulated and examined. Activation parameters without and with using of Ru (III) were calculated.

Usability of alloys with different composition as electrode for electrochemical reduction of ferricyanide ion

An experimental work was performed to investigate the usability of 8 metallic alloys with different composition in electrochemical limiting diffusion current technique employing the cathodic reduction of ferricyanide. All the alloys exhibited a limiting current plateau region in their voltage–current behaviour, but not all gave a wide and smooth plateau, except one with almost pure Ni. With the alloys of including more than 50% Ni, as Ni ratio of the metal increased, smoother and wider plateau was attained, and the electrode containing 99% Ni gave the smoothest plateau. The other alloys tested can only be used as electrode in the limiting diffusion current technique in low flow velocities in which the transfer of the active ion to the electrode surface is as slow as that the mass transfer controls the rate of system.

Nickel hexacyanoferrate/graphene thin film: a candidate for the cathode in aqueous metal-ion batteries

A reduced graphene oxide/nickel nanoparticles nanocomposite was used as precursor to synthesize a novel graphene/nickel hexacyanoferrate thin film through a heterogeneous electrochemical reaction with ferricyanide ions in solution.

Evaluation of the nutritional composition and antioxidant activity of Bjerkandera adusta

Bjerkandera adusta, a globally distributed fungus, is commonly used in the nutritional practices of the East Asian population. In this study, we evaluated the nutritional composition of the lyophilized mycelium of B. adusta as well as the phenolic composition and antioxidant activity of its extracts. The mycelium exhibited moisture (7.97 %), ash (3.27 %), and fiber (5.31 %) content values similar to the established values reported in the available literature. In addition, a high protein (9.32 %) and carbohydrate (63.45 %) content was shown, with a low lipid (1.36 %) content. The energy value per 100 g sample of mycelium was 1445.85 kJ. The results obtained indicated a statistically significant variation (p < 0.05) in the phenolic composition (81.84-110.96 mg gallic acid equivalents (GAE) per g of extract), free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (IC50 29.05-340.46 µg·mL-1), phosphomolybdenum antioxidant content (34.89-55.64 %), reduction of ferricyanide ion (66.55-69.4 %), and thiobarbituric acid reactive substance (TBARS) values (44.66-133.03 %). These results are unprecedented for this species and emphasize its nutraceutical potential.

In-situ scanning electrochemical microscopy interrogation on open-circuit release of toxic Ni2+ ion from Ni-containing carbon nanomaterials and nickel-hexacyanoferrate formation in physiological pH and its thiol-electrocatalysis relevance

The release of toxic/carcinogenic Ni2+-ion from the Nickel-embedded matrix is believed to be strongly influenced by acid solution-assisted corrosion reaction on the interface. In neutral pH, the passive nickel oxide formed on the surface is expected to protect the underlying nickel from any corrosion attack. But in reality, several biological factors are found to influence nickel corrosion and metal ion release. The present investigation is an in-situ scanning electrochemical microscopy (SECM) based mechanistic-interrogation of a commercial Ni-loaded MWCNT sample (MWCNT-Ni) that has been modified on a glassy carbon electrode surface, in presence of ferricyanide ion at a neutral pH condition. The facile chemical reaction between Ni2+ and ferricyanide ion to form Nickel-hexacyanoferrate (NiHCFOCP) at an open-circuit potential (OCP) condition in pH 7 phosphate buffer solution has been utilized as a SECM imaging tool. The surface-confined formation of NiHCFOCP on MWCNT-Ni showed a well-defined redox peak with a surface-excess value, 8.6 × 10−9 mol.cm−2. Initial scanning electron microscopic (SEM) characterization of MWCNT-Ni and MWCNT-NiHCFOCP didn't show any differentiation. On the other hand, constructed redox-competition SECM (RC-SECM) experiment yielded an obvious visualization of Ni2+ release as a specific crystalline unit due to the formation of NiHCFOCP on the MWCNT-Ni surface. Extended experiments with substrate generation-tip collection and tip generation-substrate collection modes SECM studies support the observation. This result correlates the toxic Ni2+ release from Ni-loaded carbon contaminants in the biological system at various electroactive species conditions. As an independent work, MWCNT-NiHCFOCP modified electrode has been demonstrated as an efficient and selective electrocatalyst and a home-made electrochemical detector for flow-injection analysis of thiol (cysteine as a model) in neutral pH with a detection limit of 2.08×10−12 g/20µL without any surface fouling problem.

Electrochemical Sensing of Interactions between DNA and Charged Macrocycles

In this work, we investigated aggregation of native DNA and thiacalix[4]arene derivative bearing eight terminal amino groups in cone configuration using various redox probes on the glassy carbon electrode. It was shown that sorption transfer of the aggregates on the surface of the electrode covered with carbon black resulted in changes in electrostatic interactions and diffusional permeability of the surface layer. Such changes alter the signals of ferricyanide ion, methylene green and hydroquinone as redox probes to a degree depending on their specific interactions with DNA and own charge. Inclusion of DNA in the surface layer was independently confirmed by scanning electron microscopy, electrochemical impedance spectroscopy and experiments with doxorubicin as a model intercalator. Thermal denaturing of DNA affected the charge separation on the electrode interface and the signals of redox probes. Using hydroquinone, less sensitive to electrostatic interactions, made it possible to determine from 10 pM to 1.0 nM doxorubicin (limit of detection 3 pM) after 10 min incubation. Stabilizers present in the commercial medications did not alter the signal. The DNA sensors developed can find future application in the assessment of the complexes formed by DNA and macrocycles as delivery agents for small chemical species.