KR20070121980A - Electrode preparation method for electrochemical biosensor and electrode structure thereof - Google Patents

Abstract

An electrode preparing method for an electrochemical biosensor and an electrode structure thereof are provided to improve reliability by reducing resistance of an electrode of a sensor. An electrode structure for an electrochemical biosensor comprises: an upper plate(10) equipped with a biological specimen air discharge hole(11) and a biological specimen injection hole(12), a double coated middle plate film(13) formed in a lower portion of the upper plate and equipped with an insertion path(14) for transferring biological specimens which is formed in a position corresponding to the injection hole, and an array electrode lower plate(18) formed in a lower portion of the middle plate film. The array electrode lower plate includes an electrode pattern layer equipped with a lead line, a working electrode(16) and a reference electrode(17), a nickel or chrome plating layer formed in an upper portion of the electrode pattern layer, and a gold or platinum plating layer formed in an upper portion of the nickel or chrome plating layer.

Description

Electrode preparation method for electrochemical biosensor and electrode structure

1 is a view showing an electrode array method for a biosensor having a number of horizontal 24 * vertical 13 according to an embodiment of the present invention.

Figure 2 is an equivalent circuit diagram showing the type and measurement concept of the electrode cells for electrochemical measurement applied to the present invention.

3 is an exploded perspective view of the electrochemical biosensor strip of the present invention.

Figure 4 is a process flow diagram of the electrode production for the electrochemical biosensor of the present invention.

FIG. 5 is an exploded perspective view showing the entire coupling scheme of the electrochemical biosensor strip of FIG. 3.

6 is a conceptual diagram showing a cyclic current voltage method for determining the voltage range of the electrochemical biosensor applied to the present invention.

7 is a calibration curve for the glucose standard solution of the biosensor prepared according to FIG. 4.

* Description of the symbols for the main parts of the drawings

10-top 11-biological sample air outlet

12-biosample inlet 13-mid

14-Biological sample flow path 15-meter connection

16-working electrode 17-reference electrode

18-bottom

The present invention relates to an electrode manufacturing method and an electrode structure according to the electrochemical biosensor.

As known in the art, in the preparation of electrochemical biosensor electrodes using enzyme activity, certain substances in biological samples such as glucose sensors, uric acid sensors, protein sensors, DNA sensors, It is very important to measure enzyme activity such as glutamate-oxaloacetate transaminase (GOT) or glutamate-pyruvate transaminase (GPT) more quickly and reproducibly. Here, the biosensor is divided into a part for identifying the measurement target and a part for converting into an electrical signal. The biomaterial is used for the identification part, and when the biomaterial recognizes the measurement target, chemical or physical change occurs. The conversion of these changes into an electrical signal is called a change site, which is commonly called an electrode for a biosensor.

Platinum, carbon, and silver / silver chloride ink printing methods using the conventional silk printing method of biosensor electrode manufacturing method have low device cost, but it is difficult to control resistance deviation in reproducible electrode production of sensor. There was this.

As another method, the electrode manufacturing method for the biosensor using vacuum deposition and sputtering requires a high initial investment cost and sputtering using a mask patterned with expensive metals. Or, because it is produced by the vacuum deposition method, there is a difficult problem due to the recovery of precious metals, and there is a problem of having to bear the rising cost of production cost in order to reduce the electrode resistance extremely.

Accordingly, an object of the present invention is to provide an improved electrode manufacturing method for an electrochemical biosensor and an electrode structure according to the above-mentioned problems.

Another object of the present invention is to provide a method for manufacturing an electrode for an electrochemical biosensor having high repeatability and low resistance deviation, and an electrode structure according thereto.

Still another object of the present invention is to provide a method for manufacturing an electrode for an electrochemical biosensor capable of minimizing or reducing the amount of precious metal required for manufacturing and eliminating the burden of recovering the precious metal, and an electrode structure according thereto.

Still another object of the present invention is to provide an electrode manufacturing method for an electrochemical biosensor capable of uniformly and reproducibly producing an electrode having a low resistance of 0.1 Ω or less, and an electrode structure according thereto.

Still another object of the present invention is to provide an electrode structure for electrochemical biosensors capable of solving electrode resistance value variables and quantitatively immobilizing enzymes on electrodes in analyzing specific substances in a biological sample, and an electrode structure according thereto. Is in.

It is still another object of the present invention to provide a measuring strip which can use an extremely low voltage (0.055 V or less) as an applied voltage and obtain a measurement time required within about 3 seconds when measuring glucose.

According to an embodiment of the present invention in order to achieve the above objects, a method for manufacturing an electrode for an electrochemical biosensor,

Bonding a first conductive thin film on a dielectric substrate in a laminating manner to form an array electrode lower plate formed under the double-sided adhesive mid-layer film positioned below the upper plate;

Coating an photosensitive dry film on the first conductive thin film and then performing a photolithography process to form an electrode pattern made of the first conductive thin film material to be integrally formed with a lead line, a working electrode, and a reference electrode; ;

And forming a second conductive thin film having a higher electrical conductivity than the electrical conductivity of the electrode pattern on the surface of the electrode pattern.

According to another aspect of the invention, the electrode structure for an electrochemical biosensor,

A top plate having a biological sample air outlet and a biological sample inlet;

A double-sided adhesive medium plate film positioned below the top plate and having an insertion channel for transporting the biological sample formed in a region corresponding to the biological sample inlet;

An array electrode lower plate formed under the double-sided adhesive medium plate film,

The lower electrode of the array electrode,

An electrode pattern layer constituting a lead line, a working electrode, and a reference electrode integrally formed on the same layer of copper on an insulating substrate;

A nickel or chromium plating layer formed on the electrode pattern layer;

It characterized in that it comprises a gold or platinum plating layer formed on top of the nickel or chromium plating layer.

According to the present invention described above, the manufacturing cost of the sensor is low, and as the resistance variation of the electrode for the sensor is improved, there is an effect of providing a reliable test result.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The descriptions in the various embodiments are only shown and limited by way of example and without intention other than the intent to help those of ordinary skill in the art to further understand the present invention, therefore, the scope of the invention It should not be used as a limitation.

First, in the present invention, in order to manufacture the electrode for the high quality electrochemical biosensor, which is the best use of the infrastructure in Korea, but relatively low cost, it is emerging to overcome the breadth limit of the semiconductor wiring on the insulator film rather than the conventional biosensor manufacturing method. As a material, a copper film, also called copper or kapper, is prepared and laminated to a PET film by laminating, and selectively patterned by photolithography. After the wet etching process to corrode the chemical solution, the surface of the electrode for biosensors is first plated with nickel (Ni), and then the gold (Au) is plated thinly to bio-chemical measurement method. Producing a large number of sensors makes it possible to manufacture them inexpensively in large quantities.

As another method, a copper film may be attached to the insulating film, and nickel and gold may be sequentially plated, and then a working electrode and a reference electrode may be formed by a photolithography process.

1 is a conceptual view showing an electrode array method for a biosensor having a number of horizontal 24 * vertical 13 in the production manufacturing method of the present invention. In the drawing, it can be seen that the plurality of cell electrodes 2 formed on the substrate 100 are arranged in a matrix structure.

In general, to measure the electrode potential in a solution, the potential difference between two points should be measured using two electrodes. A conceptual diagram of a cell structure generally used when measuring the potential difference is shown in FIG. 2. In the figure, the power supply is denoted by reference numeral 3, and the working electrode and reference electrode are denoted by reference numerals 16 and 17, respectively. Reference numeral 19 denotes a counter electrode.

The electrode to be measured in each cell is called a working electrode, and another electrode is connected thereto to measure the potential difference. The two-electrode cell shown on the left side of FIG. 2 is composed of a working electrode and a reference electrode, and a cell current flows between the two electrodes. When the voltage E _appl is applied between the two electrodes, a current i flows. At this time, the potential E of the working electrode can be expressed as in Equation (1) below.

E = E _appl -i R _s ---- Equation (1)

Where R _s is the resistance of the electrolyte solution. In voltammetry, in which current is measured as the potential changes, the potential of the working electrode differs from the applied potential by i R _s because of the potential drop due to the resistance of the solution. In addition, when a large current flows through the reference electrode, the concentration of the oxidizing agent and the reducing agent, which are electrochemically active species, changes at the electrode / electrolyte interface that determines the potential of the reference electrode, and thus the potential of the reference electrode deviates from the equilibrium value.

Because of this, the potential of the working electrode has a reduced value than the actual potential applied, so care must be taken when measuring. However, in the condition that i R _s value is smaller than 1 mV, it may measure using (a) 2 electrode cell in FIG. Therefore, in the electrochemical analysis using the two-electrode cell (a) in FIG.

When the electrolyte resistance is high or the current flowing is large, the (b) 3 electrode cell of FIG. 2 should be used in order to minimize errors caused by i R _s . The electrochemical cell at this time is composed of a working electrode, a reference electrode and a counter electrode. In the three-electrode cell shown on the right side of FIG. 2, a current flows between the working electrode and the counter electrode, and the potential of the working electrode is adjusted with the potential controller based on the reference electrode. At this time, the potential difference between the working electrode and the reference electrode can be measured accurately regardless of the current value flowing by the electrode reaction.

In the present invention, patterning (patterning) in a selective manner to leave only the necessary portion of the working electrode (16), reference electrode (17) and the lead line (Lead line) 15 in FIG. And a method of forming an electrochemical biosensor electrode by etching by etching.

Considering that the electrode of the electrochemical biosensor is a current measuring method, in the above description, since the oxidation current or the reduction current is caused by the reaction occurring at the unit electrode surface area, it is actually a current per unit area and is called a current density. If the area of the electrode surface is A, the current I flowing through the entire electrode surface when the current density is uniform is the current density i multiplied by A.

Therefore, I = iA and the current flows along the surface of the electrode, which is designed to properly apply the edge effect, and focuses on the electrode surface reaction in the electrochemical measurement method, and thinly plated precious metals, gold or platinum on the surface. By lowering the production cost and not participating in the electrical redox reaction, only the signal of the component to be measured can be selectively measured.

In the present invention, the resistance of the measuring electrode of the electrochemical biosensor while the resistance (resistance) of the electron flow (that is, the current) in order to smooth the flow of electrons (i.e. current) to lower the resistance component to about 0.1Ω or less to produce a constant quality of the electrode for the biosensor Stabilization and new manufacturing methods were devised. Furthermore, it is used as a disposable and continuous measurement biosensor electrode to provide more accurate measurement results to people and patients who want to perform a diagnostic test in a short time.

In order to achieve the above technical problem, the first process in FIG. 4 is a material cutting process, and the film is cut to fit. Next, a copper film 7 is attached onto the polyethylene terephthalate film aka PET film 6 by laminating. Next, a photosensitive dry film 8 for forming an electrode is subjected to a rolling coating process using a laminating machine at a temperature of about 100 to 120 ° C. preheated by a laminating method on a substrate surface.

Next is an exposure process which is a second process in FIG. 4. A working film 9, ie, a negative film, is matched to a laminated dry film, and then lighted at a predetermined intensity and exposure time. By supplying energy, a dry film of a part to be a circuit is reacted from a monomer to a polymer to reproduce a necessary pattern image 20.

Next, a third process of FIG. 4 is a developing process, in which a dry film portion that is not changed to a photocurable polymer during exposure, that is, an uncured monomer portion that is not light, is chemically treated with sodium carbonate ( Na ₂ Co ₃ ) to remove the process.

Next is a fourth process, which is a corrosion and peeling process in FIG. 4, wherein the corrosion is other than a portion covered with a dry film of the copper film on the PET film, that is, a circuit pattern ( Except for 20), the exposed copper is removed by acid-etchant (CuCl ₂ , FeCl ₂ ) or the like.

Next, a nickel (Ni) plating process, which is a fifth process of FIG. 4, is performed. In order to improve the adhesion of the conductive material to be plated during the formation of the second conductive thin film to be subjected to the cleaning process and the next process, the nickel layer is first interposed by plating. Instead of nickel, a material such as chromium (Cr) may be used.

The following is a process of plating gold (Au) or platinum (Pt) to form a second conductive thin film as a sixth process in FIG. 4, which is performed by flowing an electric current after nickel plating and undergoing a washing process. In the gold or platinum plating process, the solution on the surface is removed and then the electrode for the biosensor is completed by drying. 5 shows an exploded perspective view of the total binding of the electrochemical biosensor electrode prepared as described above. The upper plate provided with the double-sided adhesive intermediate plate insulator film 13, the biological sample air outlet 11, and the biological sample inlet 12, in which the array electrode lower plate 18 and the biological sample insertion passage 14 are completed in FIG. 10).

In the above description, a polyethylene terephthalate (PET) substrate was used as the insulating substrate, but is not limited thereto, but is not limited to polyester, polycarbonate, polystylene, polyimide, polyvinyl chloride ( At least one polymer compound film selected from polyvinylchloride and polyethylene may be used. In addition, although a copper film is used as the first conductive thin film constituting the electrode material, it is not limited thereto, and may be a copper alloy film containing a copper component such as brass or bronze as a part of the material. . Coating of the photosensitive dry film is preferably carried out by a laminating machine that performs a rolling coating on the surface of the insulating substrate at a preheating temperature of about 110 ° C., but may be coated at other temperature ranges. Of course.

The electrochemical biosensor is useful as a test strip for testing of glucose or the like.

In the present invention, the oxidative current reaction voltage value was determined using cyclic voltammetry (CV). In the method of measuring the current by circulating the potential of the working electrode at a constant speed as shown in (a) in FIG. 6, a cyclic voltammogram as shown in FIG. 6 (b) can be obtained. The cyclic voltammetry method is widely used as a method of directly determining what reaction is occurring on the electrode surface. The voltage range applied in the present invention uses an extremely low voltage (0.055 V or less) as an applied voltage and attracts ions when the measurement voltage is applied. It was possible to induce rapid enzymatic oxidation with minimal degradation.

In addition, the experiment was performed to measure the repeatability and linearity and response time of the sensor by fixing glucose oxidase on the biosensor electrode manufactured in the present invention. Reagents were prepared by mixing glucose oxidase, ferricyanide, and a surfactant at an appropriate ratio in a pH7.3 buffer solution as preparation conditions for the enzyme solution for blood glucose measurement. The enzyme was immobilized on the lower electrode prepared in the process of FIGS. 1 and 4. At this time, the enzyme solution was fixed by quantitatively fixing the sample for biometric measurement by using a multi-dispensing method of rotation using the shrinkage expansion of the polyurethane tube. As a measurement solution, a solution prepared by mixing Hartmann solution and dextrose (glucose) in a concentration ratio buffer, 1.1mM, 2.8mM, 4.3mM, 6.7mM, 11.1mM, 13.5mM, 22.2mM, 25mM, 33mM Experimental solutions similar to human blood components) were used as samples. As a result, as shown in Figure 7, using the electrode having an extremely low resistance (0.1Ω or less) of the present invention has a measurement time of less than 3 seconds with a sample of 0.25 μl or less, a very small biological sample, r (n) = 0.9893 A reproducible glucose calibration curve with linearity was obtained. In Figure 7, the horizontal axis represents the glucose concentration in mg / dl, the vertical axis represents the current in microamperes.

Biosensor electrodes using electrochemical measurement methods and carbon electrodes, gold (Au) electrodes and silver chloride (Ag / AgCl), which are electrode materials that have been tried by existing companies to reduce production costs and mass production, In the quality of electrode resistance for biological sample measurement such as an electrode, it was true that there was an error occurrence factor of the measurement result with respect to the resistance variation. These error factors can provide inaccurate measurements for consumers or patients who want to diagnose their health. However, the present invention invented a new method for manufacturing and producing a biosensor electrode, which drastically improved the resistance deviation of the electrode for the sensor, which minimized the source error of the measured value and measured the electrochemical redox. In the way of providing the value, the patient and the general public will be informed of the result of good examination with faster and more accurate measurements.

As described above, according to the present invention, the manufacturing cost of the biosensor is reduced by excellent process reproducibility and minimizing the amount of precious metal required for electrode formation. In addition, as the resistance deviation of the electrode for the sensor is improved, there is an advantage of providing more reliable test results quickly.

Claims (12)

In the electrode manufacturing method for an electrochemical biosensor: Bonding a first conductive thin film on a dielectric substrate in a laminating manner to manufacture an array electrode lower plate formed on a lower portion of a double-sided adhesive mid-layer film positioned under the upper plate to form a test strip; Coating an photosensitive dry film on the first conductive thin film and then performing a photolithography process to form an electrode pattern made of the first conductive thin film material to integrally form a lead line, a working electrode, and a reference electrode; And forming a second conductive thin film having a higher electrical conductivity than the electrical conductivity of the electrode pattern on a surface of the electrode pattern. The method of claim 1, wherein the insulating substrate is an electrochemical film characterized in that the polymer compound having a material selected from polyester, polycarbonate, polystyrene, polyimide, polyvinyl chloride, polyethylene, or polyethylene terephthalate (PET) material Electrode manufacturing method for a biosensor. The electrode manufacturing method of claim 1, wherein the first conductive thin film is made of a copper material or a copper alloy material. The electrode manufacturing method of claim 1, wherein a nickel or chromium layer is interposed between the first conductive thin film and the second conductive thin film to improve adhesion. The method of claim 1, wherein the second conductive thin film is gold or platinum. The method of claim 1, wherein the middle plate is a double-sided adhesive insulator film formed with a biological sample insertion channel corresponding to an upper portion of the working electrode of the lower plate. The method of claim 6, wherein the upper plate is formed on the upper portion of the biological sample air discharge port and the biological sample injection port corresponding to the biological sample insertion passage. In the electrode manufacturing method for an electrochemical biosensor: As the material of the insulator substrate, a copper film is adhered on polyester, polycarbonate, polystyrene, polyimide, polyvinyl chloride, polyethylene, or polyethylene terephthalate film, plated with nickel or chromium, and then plated with gold or platinum. A lithographic process, wherein a working electrode, a reference electrode, and a lead line are formed. 9. The method of claim 8, wherein the electrodes for the biosensor are arranged in plural on a substrate, each electrode having a low resistance of 0 to 0.1 Ω or less with uniform dispersion. 10. The method of claim 9, wherein the electrode for an electrochemical biosensor is driven at a low voltage of 0.055V or less when applied to a test strip and has a measurement time of about 3 seconds or less. The method of claim 10, wherein the test strip has a minimum biosample capacity of about 0.25 μL or less. In the electrode structure for an electrochemical biosensor: A top plate having a biological sample air outlet and a biological sample inlet; A double-sided adhesive medium plate film positioned below the top plate and having an insertion channel for transporting the biological sample formed in a region corresponding to the biological sample inlet; An array electrode lower plate formed under the double-sided adhesive medium plate film, The lower electrode of the array electrode, An electrode pattern layer constituting a lead line, a work electrode, and a reference electrode formed by integrally adhering to the same layer of copper on an insulating substrate; A nickel or chromium plating layer formed on the electrode pattern layer; Electrochemical biosensor electrode structure characterized in that it comprises a gold or platinum plating layer formed on top of the nickel or chromium plating layer.

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