Device for non-invasive potentiometric determination of oxidant/antioxidant activity of biological tissues

FIELD: medicine.

SUBSTANCE: group of inventions relates to medicine, cosmetology, production of food products, vitamins, food supplements, drugs and describes versions of device for realisation of non-invasive potentiometric determination of oxidant/antioxidant activity of biological tissues, which includes device for measuring potentials and double-sided electrode, made in form of plate with similar working surface, covered with electricity-conducting gel, containing mediator system. Electrodes are fixed on biological tissue in such a way that one working surface, playing role of measuring electrode, is in direct contact with biological tissue via gel, second working surface pale role of comparison electrode. Electrodes contact with each other via gel, with oxidant/antioxidant activity being determined by formulae with application of difference between final and initial potentials.

EFFECT: simplification, as well as increase of accuracy and reliability of determination, is achieved.

14 cl, 3 tbl, 4 dwg

 

The invention relates to the field of electrochemical methods of analysis, in particular to the analysis of the surface of biological tissues (including skin) to determine the integral oxidant/antioxidant activity of the examined object.

The method for evaluation of antioxidant status of the skin (international publication WO 2007/077360). The rate is measured by voltammetry using a working electrode, reference electrode and counter-electrode, placed in contact with the skin solution.

The disadvantage of this method is the use of direct skin contact of the solution, feeding the potentiostat and current source of information. The latter is not a unique function of the content of antioxidants in the object of study. It depends, along with other, not identifiable parameters also from the presence of impurities, temperature and condition of the surface of working electrode.

The known method of determining the level of carotenoids in the surface layer of the biological tissue as a measure of their antioxidant status. In the basis of measurement is the principle of Raman spectroscopy. Beam of a specific wavelength interacts with molecules of carotenoids, thus there is a shift from blue to green part of the spectrum (U.S. Patent No. 6205354).

The disadvantage of this method is that it assesses only antioxidant activity, due to carotenoids, which are only one species of a large number of antioxidants, in particular, in the skin, i.e. the concentration does not allow to judge the overall antioxidant content in the surface layer of the biological tissue.

The closest technical solution to the claimed invention is a device for noninvasive potentiometric determination of oxidant/antioxidant activity of biological tissues, including open-front casing, in which is placed connected to the device for measuring potentials, electrically interconnected conductive gel containing neurotransmitter system, the reference electrode and the measuring electrode (Patent RF №2433405).

This device has the following disadvantages.

The measurement process when using this device involves many steps: coating the surface of biological tissue in an electrically conductive gel with incorporated neurotransmitter system, the installation on the surface of biological tissue working electrode in contact with the gel containing neurotransmitter system, the introduction into contact with the gel reference electrode and then measuring. The reference electrode is disposable, which increases the measurement process. When gluing the reference electrode on the skin nebo�possible to ensure a tight fit of the measuring electrode to the uneven surface of the object. This entails the penetration of air and, consequently, the formation of air bubbles, which distorts the measurement results. In addition, the known device is complicated in structure, and performance of electrodes made of different materials and of different shapes preclude their interchangeability.

The problem solved by the present invention is to simplify the design and operation of the device, improving performance.

The technical result provided by the present invention is to reduce time in preparation for the measurement, reducing the number of operations in the operation of the device, providing the possibility of reuse, improving the accuracy and reliability of measurement results.

The technical result and the solution of this problem is achieved in that the electrodes are identical in the form of an electrically conductive metal-containing layer deposited on the opposite side of the common dielectric substrate in the form of a plate, on top of the conductive metal-containing layer is a layer of an insulator separating the conductive layer on the contact and a working zone, wherein the gel of transmitter system applied to the working area of the electrodes a uniform layer of uniform thickness not exceeding 0.3 mm. Also the technical result is achieved in that the distance�merger between the outer surfaces of the electrodes is 1.1...2.2 mm; the dielectric substrate is made of high temperature ceramic material; the body is made of flexible material, which preferably use a band-aid on a synthetic basis; the width of the insulator layer is not less than the width of the dielectric substrate plate.

The technical result is also achieved by another embodiment, characterized by the fact that the electrodes are identical in the form of a planar thick-film electrodes on top of the conductive film which is an insulating layer separating a film on contact and working zones, wherein the substrate electrodes are connected to the sides opposite to the surfaces with an electrically conductive film, and the gel of transmitter system deposited on the working areas of both electrodes with an even layer of uniform thickness.

These distinctive signs are essential and together provide the achievement of the technical result.

The implementation of identical electrodes on a common substrate, or connected reverse-conductive by the parties provides a simplified design and operation, increases the accuracy and reliability of measurements due to the exclusion of factors associated with impact on the processes of measurement of different materials, and the arrangement of working areas of the electrodes on opposite sides of the p�Daiki prevents diffusion of the test medium in the area of the reference electrode. This feature also simplifies the operation of the device. The execution of the body of flexible material, preferably plaster, allow to easily adapt the device to uneven surfaces, eliminate the formation of air bubbles between the gel and the body, and also provides a more tight fit of the gel and electrode to the sample surface. The use of adhesive plaster in combination with two-sided design is identical electrodes greatly simplifies and accelerates the process of preparation for the measurements, which minimizes the influence of external environment on the neurotransmitter system in the gel and, consequently, improves the accuracy of the measurements. The stated thickness of the gel and the distance between the surfaces of the electrodes of the selected optimal according to the results of research from the perspective of minimizing the adverse impact of processes and measurement time, which also increases the accuracy and reliability of measurement results.

Fig. 1 shows the device in General.

Fig. 2 shows a view of the electrodes in the plan.

Fig. 3 shows a view of the electrodes from the side.

Fig. 4 shows the electrodes according to the second embodiment of the invention, implemented on separate substrates.

The device for noninvasive potentiometric determination of oxidant/antioxidant activity of biological tissues contains the reference electrode 1 and edit�measuring electrode 2, made identical in the form of an electrically conductive metal-containing layer 3 deposited on the opposite side of the common dielectric substrate in the form of a plate 4. The distance between the outer surfaces of the electrodes is 1.1...2.2 mm. the Dielectric substrate is made of high temperature ceramic material. On top of the conductive layer 3 is an insulating layer 5 separating the electrically conductive layer 3 on pin 6 and 7 working zone. The width of the insulator layer 5 is not less than the width of the plate 4 dielectric substrate. On work areas 7 of the electrodes 1 and 2, uniform layer of uniform thickness less than 0.3 mm applied conductive gel 8 of transmitter system. Work areas 7 of the electrodes during the measurement are located in the housing 9, is placed with the open side on the studied object, made of a flexible material, preferably of plaster with a synthetic substrate. The contact areas 6 are electrically connected with the device for measuring potentials 10. The device is placed on the examined object 11.

According to the second embodiment of the invention, the electrodes 1 and 2 is made as a separate planar thick-film electrodes on top of the conductive layer 12 which is an insulating layer 13 separating the electrically conductive layer to the contact 14 and 15 working zone. The substrate 16 of the electrodes 1 and 2 soy�inany between the parties, opposite surfaces with an electrically conductive layer 12.

The device operates as follows.

Plate 4 with the electrodes 1 and 2, is covered with a conductive gel 8 with incorporated neurotransmitter system, is mounted on the surface of biological tissue 11, in particular of the skin, with adhesive plaster, performing the functions of the housing 9 of the device. Due to the flexibility of the hull ensures a snug fit of the device to a surface of any shape without the formation of air bubbles and air access to the gel 8. The necessary condition is the presence of work zones 7 of the electrodes 1 and 2 in contact with a conductive gel 8. Established in the system of electric potential measured by the device 10. The change in potential difference is fixed from the moment of contact of the gel and electrode with the object and before the expiration of 5-15 min.

Oxidant/antioxidant activity is determined using the difference between the final and initial potential by the formulas:

where Δ - the difference between the initial potential of the system and the value of the potential established at the end of the measurement, COx- concentration of the oxidized form of the mediator system, M; CRed- the concentration of reduced forms of the mediator system, M; AOA - antioxidant activity, mEq; OA - oxidant activity, mEq.

�length of the leg between the outer surfaces of the electrodes, which is 1.1...2.2 mm provided that the thickness of the gel on the working surfaces of the electrodes is not more than 0.3 mm is optimal, since, on the one hand, creates the conditions under which during the measurement of oxidants/antioxidants from the research object do not reach the working surface of the electrode, and on the other hand, ensures a minimum time of establishment of the stationary state diffusion processes in the gel and, consequently, leads to the correct measurement of capacity.

When the thickness of the layer of gel between the skin and the working electrode than 0.3 mm increases the diffusion time of the designated substances to the working electrode, which leads to a significant increase in measurement time. When the distance between the conductive surfaces of the electrodes is less than 1.1 mm-defined objects (oxidants/antioxidants) of time during the measurement to prodifferentiating to the surface of the electrode, thus distorting the measurement results. When the distance between the conductive surfaces of the electrodes is more than 2.2 mm increases the electrical resistance between them, which makes a significant error in the measurement result.

The dependence of the precision (error) of measurement of the thickness of the layer of electrically conductive gel and the distance between the outer surfaces of the electrodes are shown by measurement of the AOA model system�we electroconductive gel, containing neurotransmitter system and ascorbic acid at a concentration of 2×10-5M-EQ. The measurement time is 10 minutes.

Measurement error depending on the thickness of the layer of electrically conductive gel are shown in table 1.

As can be seen from table 1, with increasing thickness of the layer of gel on the electrodes increases the accuracy of measurement results. At a thickness of more than 0.3 mm, it significantly increases and becomes unacceptable - more than 15%.

Measurement error depending on the distance between the conductive surfaces of the electrodes are presented in table 2.

The measurement results show that when the distance in the range of 1.1...2.2 mm the error is in acceptable limits and does not exceed 10%, varying proportionally to the predetermined distance. If the distance is outside the specified range of distances significantly increase the magnitude of the measurement error and the spread of values.

The device was used to evaluate the oxidant-antioxidant activity of the skin in groups of patients both healthy and suffering from various diseases. Table 3 shows sample results of such measurements with the aid of the inventive device (the number of Parallels n=4-5).

As can be seen from the prima�s, the device provides a reliable assessment of oxidant/antioxidant activity of human skin depending on the condition of the body.

The proposed device, providing accurate and precise determination of oxidant/antioxidant status of live biological tissues, greatly simplifies and cheapens the process of measurement.

1. The device for noninvasive potentiometric determination of oxidant/antioxidant activity of biological tissues, including open-front casing, which are connected to the device for measuring potentials, electrically interconnected conductive gel containing neurotransmitter system, the reference electrode and the measuring electrode, characterized in that the electrodes are identical in the form of an electrically conductive metal-containing layer deposited on the opposite side of the common dielectric substrate in the form of a plate, and on top of the conductive metal-containing layer is an insulating layer separating the electrically conductive layer is in contact and working areas, the gel of transmitter system applied to the working area of the electrodes a uniform layer of equal thickness.

2. The device according to claim 1, characterized in that the thickness of the layer of gel on the working areas of the electrodes is not more� 0.3 mm.

3. The device according to claim 1, characterized in that the distance between the outer surfaces of the electrodes is 1.1...2.2 mm.

4. The device according to claim 1, characterized in that the dielectric substrate is made of high temperature ceramic material.

5. The device according to claim 1, characterized in that the casing is made of flexible material.

6. Device according to claims.1, 5, characterized in that as the material of the body using a band-aid on a synthetic substrate.

7. The device according to claim 1, characterized in that the width of the layer of the insulator is not less than the width of the dielectric substrate plate.

8. The device for noninvasive potentiometric determination of oxidant/antioxidant activity of biological tissues, including open-front casing, which are connected to the device for measuring potentials, electrically interconnected conductive gel containing neurotransmitter system, the reference electrode and the measuring electrode, characterized in that the electrodes are identical in the form of a planar thick-film electrodes on top of the conductive metal-containing layer which is a layer of an insulator separating the conductive metal-containing layer on the contact and working zones, wherein the substrate electrodes are connected storo�AMI, opposite surfaces with an electrically conductive layer, and the gel of transmitter system deposited on the working areas of both electrodes with an even layer of uniform thickness.

9. The device according to claim 8, characterized in that the thickness of the layer of gel on the working areas of the electrodes is not more than 0.3 mm.

10. The device according to claim 8, characterized in that the distance between the outer surfaces of the electrodes is 1.1...2.2 mm.

11. The device according to claim 8, characterized in that the substrate electrode is made of high temperature ceramic material.

12. The device according to claim 8, characterized in that the casing is made of flexible material.

13. Device according to claims.8, 12, characterized in that as the material of the body using a band-aid on a synthetic substrate.

14. The device according to claim 8, characterized in that the width of the layer of the insulator is not less than the width of the substrate electrodes.



 

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