- Prussian Blue based selective electrocatalyst for hydrogen peroxide reduction (artificial peroxidase). Application to biosensors.
- A.A. Karyakin, O.V. Gitelmacher, E.E. Karyakina. A high sensitive glucose amperometric
biosensor based on Prussian Blue modified electrodes. Analyt. Letters 27(15) (1994) 2861-
2869.
- A.A. Karyakin, O.V. Gitelmacher, E.E. Karyakina. Prussian Blue based first generation
biosensors. A high sensitive amperometric electrode for glucose. Anal. Chem. 67 (1995) 2419-
2423.
A first-generation amperometric glucose biosensor based on a Prussian Blue-modified electrode was developed. Prussian Blue was a better electrocatalyst for hydrogen peroxide redn. than platinum. H2O2 was detected at the Prussian Blue-modified electrode in the presence of oxygen by both electrooxidn. and electroredn. The glucose amperometric biosensor was made by glucose oxidase immobilization onto a Prussian Blue-modified electrode with a Nafion layer. The biosensor response exhibited a linear dependence on analyte concn. in the range 1x10-6-5x10-3 M. The cathodic c.d. after addn. of 10-6 M glucose was 0.18 mA/cm2. When hydrogen peroxide produced via the enzyme reaction was detected by electroredn., the biosensor response was independent of reductants. This amperometric biosensor is expected to obey the requirements for noninvasive diagnostics.
- A.A. Karyakin, E.E. Karyakina, L. Gorton. Prussian Blue based amperometric biosensors in
flow-injection analysis. Talanta 43 (1996) 1597-1606.
Optimisation of the electrodeposition of Prussian Blue onto mirrored glassy carbon electrodes yielded a modified electrode practically insensitive to oxygen reduction. At the same time the electrode activity towards hydrogen peroxide reduction was extremely high. This allowed the detection of hydrogen peroxide by electroreduction over a wide potential range. Flow-injection investigations of this electrode inserted into a flowthrough electrochemical cell of the confined wall-jet type showed that the response for hydrogen peroxide is limited by diffusion. Glucose and alcohol biosensors were made by immobilisation of glucose oxidase and alcohol oxidase respectively, within a Nafion layer, onto the top of the Prussian-Blue-modified electrodes. By increasing the density of Nafion and decreasing the measuring potential the glucose biosensor was made completely insensitive to both ascorbate and acetominophes.
- A.A. Karyakin, E.E. Karyakina, L. Gorton. The electrocatalytic activity of Prussian Blue in
hydrogen peroxide reduction studied using wall-jet cell with continuous flow. J. Electroanal.
Chem. 456 (1998) 97-104.
The kinetics of hydrogen peroxide reduction on electrodes modified with specially deposited Prussian Blue was investigated using a wall-jet cell with continuous flow. For this aim a new semi-empirical model for the diffusion limited current distribution holding for narrow wall-jet electrodes was described. In spite of a nonuniform accessibility of the wall-jet electrode surface in terms of mass transport the evaluated equation for the total current density (j) allowed the separation of the diffusion and kinetic terms of the current through investigating the dependence of j on the volume flow rate (V) in (1/j vs. V-3/4) plots. The theoretical conclusions presented were confirmed by kinetic investigations of the electrocatalytic reduction of H2O2 at glassy carbon wall-jet electrodes modified with Prussian Blue. The bimolecular rate constant for the reduction of H2O2 on the specially deposited Prussian Blue was found to be kcat = 3x103 M-1s-1. Due to the characteristics of the high catalytic activity and selectivity, which were comparable with biocatalysis using peroxidase, the Prussian Blue based electrocatalyst is denoted as "artificial peroxidase".
- A.A. Karyakin, O.V. Gitelmacher, E.E. Karyakina. A high sensitive glucose amperometric
biosensor based on Prussian Blue modified electrodes. Analyt. Letters 27(15) (1994) 2861-
2869.
- Polyaniline as an advanced transducer for potentiometric biosensors.
- A.A. Karyakin, A.K. Strakhova, A.K. Yatsimirsky. Self-doped polyanilines
electrochemically active in neutral and basic aqueous solutions. Electropolymerizations of
substituted anilines. J. Electroanal. Chem. 371 (1994) 259-265.
To obtain polyaniline (PAn) films that are electrochemically active in neutral aqueous solutions, the electropolymerization of three substituted anilines (anthranilic acid, m-aminobenzoic acid and m-aminobenzenesulphonic acid) was studied. Cyclic voltammograms of copolymers of substituted and unsubstituted anilines (monomer ratio 1:1) showed redox activity in neutral and basic aqueous solutions up to pH 10. The decrease in redox activity occurred more than 5 pH units higher than in the case of the usual PAn. Among aniline derivatives taken for the synthesis, a meta position and a sulpho group were preferable to produce the optimal self-doped PAn. A new redox couple in the negative potential region (E(o') = -0.24 V, Ag/AgCl, pH = 1) was observed. Self-doped polyanilines were also investigated by means of impedance spectroscopy.
- E.E. Karyakina, L.V. Neftyakova, A.A. Karyakin. A novel potentiometric glucose biosensor
based on polyaniline semiconductor film. Analyt. Letters 27(15) (1994) 2871-2882.
Application of polyaniline semiconductor films to potentiometric biosensor development provides certain advantages comparing with the known systems. Using self-doped polyaniline instead of common polymer as pH transducer the stable potentiometric response of 70 mV/pH was obtained. Taking as an example glucose biosensor we showed that polyaniline based electrode possessed three-four fold increased potential shift than glucose-sensitive field-effect transistor did. One can increase the sensitivity of potentiometric biosensor using thick ion-exchange membranes (in our case Nafion) in order to concentrate product near electrode surface. Such sensor possessed higher response time.
- A. A. Karyakin, I. A. Maltsev, L. V. Lukachova. The influense of the defects in polyaniline
structure on its electroactivity. The optimisation of 'self-doped' polyaniline synthesis. J.
Electroanal. Chem. 402 (1996) 217-219.
- A.A. Karyakin, O.A. Bobrova, L.V. Lukachova, E.E. Karyakina. Potentiometric biosensors
based on polyaniline semiconductor films. Sensors & Actuators B 33 (1996) 34-38.
A potentiometric biosensor based on semiconductor polyaniline is developed. The potentiometric response of the polyaniline films to a change in pH is 65-70 mV per pH unit, which is higher than that of the known pH transducers. The polyaniline films prepared by electropolymerization contained immobilized trypsin as a model enzyme. The high potentiometric response of the polyaniline films and the incorporation of enzyme into the pH-sensitive matrix ensured high sensitivity of the biosensor. The potentiometric electrode thus produced can be used for analyzing substrate concentrations ranging from 5 x 10-5 to 1 x 10-2 M. Th, time response does not exceed 20-40 s. The maximum potentiometric response of the electrode reaches 270 mV in a 0.001 M phosphate buffer.
- A.A. Karyakin, E.E. Karyakina. Polyaniline based potentiometric biosensors. Abstracts Of Papers Of the American Chemical Society 213/pt 2 (1997) 314-PMSE.
- A.A. Karyakin, A.K. Strakhova, A.K. Yatsimirsky. Self-doped polyanilines
electrochemically active in neutral and basic aqueous solutions. Electropolymerizations of
substituted anilines. J. Electroanal. Chem. 371 (1994) 259-265.
- Electropolymerisation of azines: a new group of electroactive polymers. Application to dehydrogenase based biosensors.
- A.A. Karyakin, A.K. Strakhova, E.E. Karyakina, S.D. Varfolomeyev, A.K. Yatsimirsky.
The electrochemical polymerization of methylene blue and bioelectrochemical activity of the
resulting film. Bioelectrochem. & Bioenergetics 32 (1993) 35-43.
The electrochemical polymerization of Methylene Blue in aqueous solutions and the properties of the resulting films were investigated. These films possessed monomer-type redox activity. In addition, a new redox couple, responsible for polymer semiconductor properties, was observed. Film growth rate increased in basic media. The hydroxide ion influence could be simulated in terms of both nucleophilic catalysis and shielding effect. Bioelectrochemical glucose oxidation took place at Methylene Blue semiconductor films in the presence of glucose oxidase.
- A.A. Karyakin, E.E. Karyakina, W. Schuhmann, H.-L. Schmidt & S.D. Varfolomeyev. New
amperometric dehydrogenase electrodes based on electrocatalytic NADH-oxidation at
poly(Methylene Blue)-modified electrodes. Electroanalysis 6 (1994) 821-829.
Poly(methylene blue) (PMB)-modified electrodes show excellent properties for the electrocatalytic oxidn. of NADH with respect to optimal working potential of 0-100 mV (vs. SCE) and their operation stability. By dehydrogenases entrapped within a Nafion film on top of the PMB layer, new amperometric biosensors for glucose, lactate, malate, and ethanol could be obtained with improved integration of the enzyme and the electrocatalyst directly on the electrode surface. Coentrapment of the neg. charged NAD+ within the neg. charged Nafion polyelectrolyte leads to reagentless dehydrogenase electrodes for one-shot or short-term applications. - D.D. Schlereth, A.A. Karyakin. Electropolymerisation of phenothiazine, phenoxazine and
phenazine derivatives: characterisation of the polymers by UV-visible difference
spectroelectrochemistry and Fourier transform IR spectroscopy. J. Electroanal. Chem. 395
(1995) 221-232.
- A. A. Karyakin, O. A. Bobrova, E. E. Karyakina. Electroreduction of NAD+ to
enzymatically active NADH at poly(Neutral Red) modified electrodes. J. Electroanal. Chem.,
399 (1-2) (1995) 179-184.
- A.A. Karyakin, E.E. Karyakina, H.-L. Schmidt. Electropolymerized azines: a new group of
electroactive polymers. Electroanalysis (1999) to be published.
The electropolymerisation of different azines from aqueous solutions was investigated. The structure of monomers was systematically varied changing both the nature of the second heteroatom and the substituents in the aromatic rings. Considering the electropolymerisation process and the properties of the resulting polymers one can denote polyazines as a new group of electroactive polymers. The electrochemical and spectroelectrochemical investigation of polyazines was done. A hypothesis on azine polymer structure is presented.
- A.A. Karyakin, A.K. Strakhova, E.E. Karyakina, S.D. Varfolomeyev, A.K. Yatsimirsky.
The electrochemical polymerization of methylene blue and bioelectrochemical activity of the
resulting film. Bioelectrochem. & Bioenergetics 32 (1993) 35-43.
- Non-aqueous enzymology approach for biosensor development.
- A. A. Karyakin, E. E. Karyakina, L. Gorton, O. A. Bobrova, L. V. Lukachova, A. K.
Gladilin, A. V. Levashov. The improvement of electrochemical biosensors using enzyme
immobilisaiton from water-organic mixtures with a high content of organic solvent. Anal.
Chem. 68 (1996) 4335-4341.
We propose immobilizing enzymes into Nafion mem membranes by suspending the enzyme in a water-ethanol mixture with a high (> 90%) ethanol content, followed by mixing with the dissolved polyelectrolyte, and finally allowing the enzyme-polyelectrolyte solution to dry at the target surface (electrode surface). Since Nafion solution was deposited from a solution where it is truly dissolved and without excessive dilution with water, the resulting membranes were more uniform and stable than those otherwise obtained. Enzyme suspensions in concentrated ethanol solutions were prepared without any prior modifications of the protein. The remaining activity after 30 min exposure to such solutions under optimal conditions was up to 100%. The stability of the enzymes in these suspensions was higher than that in aqueous solution. Electrochemical biosensors made accordingly showed a several times increased response compared with those of enzyme electrodes based on the traditional way of using excessive dilution of Nafion with water. The remaining activity, after the drying-washing cycle of the enzyme electrode made by enzyme immobilization from concentrated organic solvent, was at least 10 times higher thats that of the traditional one.
- L.V. Lukachova, A.A. Karyakin, E.E. Karyakina, L. Gorton. The improvement of
polyaniline glucose biosensor stability using enzyme immobilization from water-organic
mixtures with a high content of organic solvent. Sensors & Actuators B. Chemical 44/1-3
(1997) 356-360.
Immobilization of a glucose oxidase (GOD) into Nafion membranes is proposed by suspending the enzyme in a water-ethanol mixture with a high (>90%) ethanol content, mixing with the polyelectrolyte-solution, and drying al the target surface. Since Nafion was deposited from its real solution without excessive dissolving with water, the resulting membranes were more uniform and stable. The enzyme suspension in concentrated ethanol solutions were prepared without ally prior modifications of the protein. The remaining activity of glucose oxidase after 30-min exposure to such solutions under optimal conditions was up to 100%. The stability of the GOD in these suspensions Res higher than in aqueous solution. Potentiometric polyaniline-based biosensor made according to the proposed method of enzyme immobilization showed a several times increased response as compared with enzyme electrodes developed in the traditional way using excessive dilution of Nafion with water. The remaining activity of the enzyme electrode made by GOD immobilization from concentrated organic solvent was 95-100% after several drying-washing cycles. (C) 1997 Elsevier Science S.A.
- L.V. Lukachova, A.A. Karyakin, Y.N. Ivanova, E.E. Karyakina, S.D. Varfolomeyev. Non-
aqueous enzymology approach for improvement of reagentless mediator based glucose
biosensor. Analyst 123 (1998) 1981-6.
Formation of Nafion membranes containing glucose oxidase and dimethylferrocene as a mediator, have been optimized using our previously reported non-aqueous enzymology approach for biosensor development. Enzyme immobilization in Nafion membranes was carried out from water-organic mixtures with the high content of organic solvent. The mediator based reagentless glucose electrode was tested in flow-injection system. The response towards glucose addition was stable: the reproducibility during 50 assays exceeded 95%. The response was linear in glucose concentration range of 0.5 - 50 mM.
- A. A. Karyakin, E. E. Karyakina, L. Gorton, O. A. Bobrova, L. V. Lukachova, A. K.
Gladilin, A. V. Levashov. The improvement of electrochemical biosensors using enzyme
immobilisaiton from water-organic mixtures with a high content of organic solvent. Anal.
Chem. 68 (1996) 4335-4341.
- Theory on current distrbution on wall-jet electrodes. New method of investigation of the electrochemical kinetics in wall-jet flow-through cell.
- A.A. Karyakin, E.E. Karyakina, L. Gorton. The electrocatalytic activity of Prussian Blue in
hydrogen peroxide reduction studied using wall-jet cell with continuous flow. J. Electroanal.
Chem. 456 (1998) 97-104.
The kinetics of hydrogen peroxide reduction on electrodes modified with specially deposited Prussian Blue was investigated using a wall-jet cell with continuous flow. For this aim a new semi-empirical model for the diffusion limited current distribution holding for narrow wall-jet electrodes was described. In spite of a nonuniform accessibility of the wall-jet electrode surface in terms of mass transport the evaluated equation for the total current density (j) allowed the separation of the diffusion and kinetic terms of the current through investigating the dependence of j on the volume flow rate (V) in (1/j vs. V-3/4) plots. The theoretical conclusions presented were confirmed by kinetic investigations of the electrocatalytic reduction of H2O2 at glassy carbon wall-jet electrodes modified with Prussian Blue. The bimolecular rate constant for the reduction of H2O2 on the specially deposited Prussian Blue was found to be kcat = 3x103 M-1s-1. Due to the characteristics of the high catalytic activity and selectivity, which were comparable with biocatalysis using peroxidase, the Prussian Blue based electrocatalyst is denoted as "artificial peroxidase".
- A.A. Karyakin, E.E. Karyakina, L. Gorton. The electrocatalytic activity of Prussian Blue in
hydrogen peroxide reduction studied using wall-jet cell with continuous flow. J. Electroanal.
Chem. 456 (1998) 97-104.
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