KR102255442B1 - Bio sensor - Google Patents

Abstract

The biosensor of the exemplary embodiments of the present invention includes a substrate, a working electrode and a reference electrode each having a concave-convex shape on the substrate and each having a first facing surface and a second facing surface facing each other. As the area of the surface of the working electrode and the reference electrode facing each other increases, sensing performance may be improved.

Description

Bio sensor {BIO SENSOR}

The present invention relates to a biosensor. More specifically, it relates to a biosensor including a working electrode and a reference electrode.

As the life expectancy of humans increases, the healthcare industry is expanding rapidly. In particular, there is a growing demand for a portable small biosensor that can conveniently measure various bio-signals anywhere.

Conventional biosensors use enzymes that react with chemical species contained in body fluids (sweat, tears, blood, etc.). When the enzyme reacts with the chemical species to generate an electric current, it is measured to measure the concentration of the chemical species.

Most of the studies on biosensors are, for example, as disclosed in Korean Patent Publication No. 10-1107506, glucose oxidase or glucose dehydrogenase that promotes the oxidation of glucose to gluconolactone. It is based on the immobilization of enzymes such as enzymes.

To drive the biosensor, a predetermined amount of sample must be supplied to the sensor electrode. The higher the minimum sample requirement of the sensor, the more difficult it is to obtain a corresponding amount of sample (eg, sweat or blood).

Republic of Korea Patent Publication No. 10-1107506

An object of the present invention is to provide a biosensor with improved convenience and improved sensing performance.

1. a substrate; A working electrode disposed on the substrate and including a first opposing surface having an uneven shape; And a reference electrode including a second facing surface on the substrate, facing and spaced apart from the working electrode, facing the first facing surface, and having a concave-convex shape.

2. The biosensor according to the above 1, wherein the first facing surface and the second facing surface include a convex portion and a concave portion.

3. In the above 2, the convex portion of the first facing surface is disposed to face the concave portion of the second facing surface, and the concave portion of the first facing surface is disposed with the convex portion of the second facing surface. Biosensors placed facing each other.

4. In the above 3, the shape of the convex portion and the shape of the concave portion are in a complementary relationship, the biosensor.

5. The biosensor according to the above 1, wherein the uneven shape is formed on the entire first and second facing surfaces.

6. The biosensor according to the above 1, wherein the concave-convex shape of the first facing surface and the concave-convex shape of the second facing surface do not cross a center line of the working electrode and the reference electrode.

7. The biosensor according to the above 1, wherein the working electrode and the reference electrode define a sensing electrode, and the total width of the sensing electrode is 0.3 to 5 mm.

8. The biosensor according to the above 1, wherein the area of the working electrode is greater than or equal to the area of the reference electrode.

9. The biosensor according to the above 1, wherein the area of the working electrode is 1 to 15 times the area of the reference electrode.

10. In the above 1, the working electrode, the conductive layer disposed on the substrate; An electron transport layer disposed on the conductive layer; And an enzyme reaction layer disposed on the electron transport layer.

11. In the above 10, the enzyme reaction layer is at least one of glucose oxidase, cholesterol oxidase, lactate oxidase, ascorbic acid oxidase and alcohol oxidase, or glucose dehydrogenase, glutamic acid dehydrogenase, lactate A biosensor comprising at least one dehydrogenase of dehydrogenase and alcohol dehydrogenase.

12. The biosensor according to the above 10, wherein the electron transport layer includes Prussian blue.

13. The biosensor according to the above 10, wherein the conductive layer includes a metal layer and a metal protective layer.

14. In the above 13, the metal layer is a biosensor containing at least one of Au, Ag, Cu, Pt, Ti, Ni, Sn, Mo, Co, Pd, and alloys thereof.

15. The biosensor according to the above 13, wherein the metal protective layer includes Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO).

16. The biosensor according to the above 10, wherein the working electrode further comprises a filter layer disposed on the enzyme reaction layer.

According to exemplary embodiments of the present invention, the working electrode and the reference electrode are disposed to face each other, and the opposite surfaces each have an uneven profile. In this case, the area of the facing surface may be increased compared to the total size of the sensing electrode. Therefore, it is possible to reduce the minimum sample requirement and improve sensing sensitivity and speed.

According to example embodiments, the uneven patterns of the first and second facing surfaces may be complementarily opposed to each other and disposed. Accordingly, the area of the facing surface can be further increased compared to the total area of the sensing electrode.

1 is a schematic plan view of a biosensor according to exemplary embodiments.
2 to 4 are schematic plan views of sensing electrodes according to exemplary embodiments.
5 and 6 are schematic plan views of sensing electrodes according to comparative examples.
7 is a schematic cross-sectional view of a sensing electrode according to exemplary embodiments.
8 is a time-current graph of measuring a glucose sample with a biosensor according to Examples and Comparative Examples.
9 is a time-current graph obtained by measuring a glucose sample with a biosensor according to embodiments.

Exemplary embodiments of the present invention provide a substrate, a biosensor including a working electrode and a reference electrode each having a concave-convex shape on the substrate and each having a first and second opposed surfaces facing each other. As the area of the surface of the working electrode and the reference electrode facing each other increases, sensing performance may be improved.

1 is a schematic plan view of a biosensor according to example embodiments.

Referring to FIG. 1, a biosensor 10 according to exemplary embodiments includes a substrate 100, a working electrode 110, a reference electrode 120, and a wiring 140. In addition, an auxiliary sensor 130 may be further included.

The substrate 100 is provided as a base layer on which the working electrode 110, the reference electrode 120, the wiring 140, and/or the auxiliary sensor 130 are disposed.

For example, the substrate 100 may be a base film having flexible properties, and specific examples include polyester-based resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; Cellulose resins such as diacetyl cellulose and triacetyl cellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin resins such as polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, and ethylene-propylene copolymer; Vinyl chloride resin; Amide resins such as nylon and aromatic polyamide; Imide resin; Polyethersulfone resin; Sulfone resin; Polyether ether ketone resin; Sulfide polyphenylene resin; Vinyl alcohol resin; Vinylidene chloride resin; Vinyl butyral resin; Allylate resin; Polyoxymethylene resin; A film composed of a thermoplastic resin such as an epoxy resin may be used, and a film composed of a blend of the thermoplastic resin may also be used. In addition, a film made of a thermosetting resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, silicone, or an ultraviolet curable resin may be used.

The thickness of the substrate 100 may be appropriately determined, but may be 1 to 500 μm in consideration of strength, handling properties, workability, thin layer properties, and the like. It is preferably 1 to 300 µm, and more preferably 5 to 200 µm.

For example, the base film may contain one or more additives. Examples of the additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, colorants, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like.

In some embodiments, the base film may include various functional layers such as a hard coating layer, an antireflection layer, and a gas barrier layer on one or both sides of the film.

In some embodiments, the base film may be surface-treated. For example, the surface treatment may include chemical treatment such as plasma treatment, corona treatment, dry treatment such as primer treatment, and alkali treatment including saponification treatment.

The sensing electrode may be formed on the substrate 100. The sensing electrodes may include a working electrode 110 and a reference electrode 120 facing each other and spaced apart from each other. According to some embodiments, the working electrode 110 and the reference electrode 120 may be disposed to face left and right.

Therefore, when a sample is supplied between the working electrode 110 and the reference electrode 120, the sample may mediate the movement of electrons/holes and the oxidation-reduction material between the working electrode 110 and the reference electrode 120. I can. Therefore, it is possible to drive the biosensor 10 with a small amount of sample.

2 is a schematic plan view of a sensing electrode according to exemplary embodiments.

Referring to FIG. 2, the working electrode 110 may include a first facing surface 112, and the reference electrode 120 may include a second facing surface 122.

The first facing surface 112 may be defined as a surface where the working electrode 110 faces the reference electrode 120. The second facing surface 122 may be defined as a surface where the reference electrode 120 faces the working electrode 110. For example, two surfaces of the working electrode 110 and the reference electrode 120 facing each other may be defined as a first facing surface 112 and a second facing surface 122, respectively.

The first facing surface 112 of the working electrode 110 and the second facing surface 122 of the reference electrode 120 may face left and right. The first facing surface 112 and the second facing surface 122 may have an uneven shape.

In example embodiments, profiles of the first facing surface 112 and the second facing surface 122 may each include an uneven shape. For example, as shown in FIG. 2, when viewed in a planar direction, line segments facing the first facing surface 112 and the second facing surface 122 may have an uneven shape. When the facing surfaces include an uneven profile, an area of the facing surface may increase compared to the size of the sensing electrode. The uneven shape may be formed on the entire first and second facing surfaces 112 and 122.

In example embodiments, the uneven shape may include a convex portion and a concave portion. The convex portion and the concave portion may be alternately repeated.

For example, the first facing surface 112 may include a first convex portion 112a and a first concave portion 112b, and the second facing surface 122 is a second concave portion 122a and a second concave portion 122a. It may include two convex portions 122b.

The first convex portion 112a, the first concave portion 112b, the second concave portion 122a, and the second convex portion 122b may have a blunt curved profile. The blunt curve profile may include, for example, a wavy shape.

In example embodiments, the rest of the side surfaces of the working electrode 110 except for the first facing surface 112 may have a curved shape without irregularities. The curved shape without irregularities may be, for example, a seamless shape. The rest of the side surfaces of the reference electrode 120 except for the second facing surface 122 may also have a curved shape without irregularities.

In some embodiments, the working electrode 110 and the reference electrode 120 may have a semicircular shape as a whole. For example, side surfaces (sidewalls) of the working electrode 110 and the reference electrode 120 excluding the first and second facing surfaces 112 and 122 may have a semicircular profile.

In example embodiments, the first convex portion 112a may be disposed to face the second concave portion 122a, and the first concave portion 112b may be disposed to face the second convex portion 122b. have. Accordingly, by pairing the concave-convex shape, the facing area per unit size of the sensor can be increased.

In example embodiments, the shape of the convex portion and the shape of the concave portion may have a complementary relationship. The term “complementary relationship” used in the present specification means that when two shapes are attached, they are substantially integrated without an empty space, but may include a case including a predetermined tolerance. For example, when the working electrode 110 and the reference electrode 120 shown in FIG. 2 are connected together, an integrated circle or ellipse may be formed. When the complementary relationship is satisfied, an area facing each sensor unit size may increase.

In example embodiments, the length of the first facing surface 112 may be substantially the same as the length of the second facing surface 122. The lengths of the first and second facing surfaces 112 and 122 may mean the length of the uneven profile.

In example embodiments, the working electrode 110 and the reference electrode 120 may define a sensing electrode. The sensing electrodes may cover a pair of opposing working electrodes 110, reference electrodes 120, and spaced apart spaces therebetween.

The term “the total width of the sensing electrode” as used herein may mean a distance between the two most distant points of the working electrode 110 and the reference electrode 120.

In example embodiments, the total width of the sensing electrode may be 0.3 to 5 mm. When the total width is less than 0.3 mm, the amount of the electric signal (current) generated when measuring the sensing target material decreases, so that the sensitivity, the measurement speed, and/or the maximum measurement concentration of the biosensor may decrease. When the total width is greater than 5 mm, the minimum amount of sample required to drive the sensing electrode may increase.

In some embodiments, the minimum sample requirement of the biosensor 10 may be 0.1 to 1 μl. For example, when the total width of the sensing electrode is 0.3 to 5 mm, the biosensor 10 may be driven with a sample of about 1 μl or less.

3 is a schematic plan view of a sensing electrode according to exemplary embodiments. Description of the configuration substantially the same as the configuration described with reference to FIG. 2 may be omitted.

Referring to FIG. 3, the sensing electrode may include a working electrode 111 and a reference electrode 121. The working electrode 111 may include a first facing surface 113, and the first facing surface 113 may include a first convex portion 113a and a first concave portion 113b. The reference electrode 121 may include a second facing surface 123, and the second facing surface 123 may include a second concave portion 123a and a second convex portion 123b.

The first convex portion 113a, the first concave portion 113b, the second concave portion 123a, and the second convex portion 123b may include a tip portion. The first convex portion 113a and the first concave portion 113b may form a sawtooth shape. In addition, the second concave portion 123a and the second convex portion 123b may have a sawtooth shape.

In example embodiments, the working electrode 110 and the reference electrode 120 may have substantially the same area.

4 is a schematic plan view of a sensing electrode according to exemplary embodiments.

Referring to FIG. 4, the area of the working electrode 110 may be larger than the area of the reference electrode 120. In this case, the ratio of the area of the working electrode 110 to the total area of the sensing electrode may increase. Accordingly, a larger amount of sample may be applied to the working electrode 110, and detection sensitivity and speed may be improved. In addition, even when the amount of sample is small, sufficient sensing sensitivity can be secured.

The area of the working electrode 110 and the reference electrode 120 may mean an area of the electrode itself excluding the working electrode 110 and the wires 142 and 144 connected to the reference electrode 120.

In example embodiments, the area of the working electrode 110 may be 1 to 15 times the area of the reference electrode 120. When the area of the working electrode 110 is less than 1 times, the sensing performance may not be improved. When the area of the working electrode 110 is more than 15 times, the area of the reference electrode 120 is excessively reduced, and the sensor may not be driven because it cannot function as a reference electrode. Preferably, the area of the working electrode 110 may be 3 to 12 times the area of the reference electrode 120.

5 is a schematic plan view of a sensing electrode according to a comparative example.

Referring to FIG. 5, the sensing electrode of the comparative example includes a working electrode 210 and a reference electrode 220, and may be connected to a first wiring 242 and a second wiring 244, respectively.

The sensing electrode of FIG. 5 may have a structure in which the reference electrode 220 surrounds the working electrode 210. In this case, a sample of an amount capable of covering the working electrode 210 and the reference electrode 220 together may be required to drive the sensor. Accordingly, the minimum amount of sample required for driving the sensor can be increased.

In addition, when the size of the working electrode 210 of the comparative example is matched with the size of the working electrode 110 of the embodiment, the overall size of the sensing electrode of the comparative example may increase. Accordingly, the minimum sample required amount for covering the working electrode 210 and the reference electrode 220 together can be increased. When the overall size of the sensing electrode of the comparative example is matched with the overall size of the sensing electrode of the embodiment, the size of the working electrode 210 of the comparative example may be smaller than the size of the working electrode 110 of the embodiment. Accordingly, the sensitivity of the sensor, the maximum measurement concentration, and the sensing speed may be reduced.

In example embodiments, the concave-convex shape of the first facing surface 112 and the concave-convex shape of the second facing surface 122 exceed the center line CL of the working electrode 110 and the reference electrode 120. I can't go.

The center line CL may be defined as a line crossing an intermediate point between the first concave portion 112b of the first facing surface 112 and the second concave portion 122a of the second facing surface 122. For example, the center line CL may mean a line perpendicular to the width direction of the sensing electrode from a midpoint of a distance between the first concave portion 112b and the second concave portion 122a. Further, the center line CL may mean a line that crosses an intermediate point between the first wiring 142 connected to the working electrode 110 and the second wiring 144 connected to the reference electrode 120.

In some embodiments, the first convex portion 112a of the first facing surface 112 may not be inserted into the second concave portion 122a of the second facing surface 122. For example, the first convex portion 112a may not cross a line connecting the maximum protruding points of the second facing surface 122 and the second convex portion 122b.

6 is a schematic plan view of a sensing electrode according to a comparative example.

Referring to FIG. 6, in the sensing electrode of the comparative example, a portion of the uneven shape of the working electrode 310 and a portion of the uneven shape of the reference electrode 320 may cross the center line CL.

In this case, for example, when the working electrode 310 is manufactured, the enzyme reaction layer may not be evenly applied to the entire surface of the working electrode 310 due to the surface tension of the composition for forming the enzyme reaction layer. Accordingly, sensing sensitivity, sensing accuracy, and sensing accuracy of the biosensor may be deteriorated.

According to exemplary embodiments, by designing the shape of the electrode so that the uneven shapes of the working electrode 110 and the reference electrode 120 do not cross the center line CL, a uniform enzyme reaction on the working electrode 110 Layers can be formed. In this case, sensing sensitivity, sensing accuracy, and sensing accuracy may be improved.

The wiring 140 may be connected to the sensing electrode. The wiring 140 may include a first wiring 142 connected to the working electrode 110 and a second wiring 144 connected to the reference electrode 120. In addition, a third wiring 146 connected to the auxiliary sensor 130 may be included.

The auxiliary sensor 130 may include a heat sensor, a pH sensor, and/or a humidity sensor. For example, the auxiliary sensor 130 may measure temperature, pH and/or humidity to correct a measurement error of the biosensor 10.

7 is a schematic cross-sectional view of a sensing electrode according to exemplary embodiments.

Referring to FIG. 7, the working electrode 110 may include a conductive layer 114, an electron transport layer 115, and an enzyme reaction layer 116. In addition, a filter layer 117 may be further included. The conductive layer 114 may include a metal layer 114a and a metal protective layer 114b. The reference electrode 120 may include a second conductive layer 124 and a reference material layer 126.

In the working electrode 110, an oxidation-reduction reaction of a sensing target material (measurement target material) may occur. The working electrode 110 may detect an electrical signal generated by the reaction of the sensing target material included in the sample. The sample may be sweat, body fluid, tear, blood, etc., but is not limited thereto.

For example, the detection target material may include glucose or lactic acid (lactate).

The conductive layer 114 may be disposed on the substrate 100. The conductive layer 114 may be provided as a path through which electrons or holes generated in an oxidation-reduction reaction of a material to be sensed are transferred.

In example embodiments, the conductive layer 114 may include a metal layer 114a and a metal protective layer 114b.

The metal protective layer 114b may entirely cover the upper surface of the metal layer 114a. For example, the metal protective layer 114b may directly contact the metal layer 114a. The metal protective layer 114b may prevent oxidation-reduction of the metal layer 114a due to an oxidation-reduction reaction.

In example embodiments, the metal layer 114a may include at least one of Au, Ag, Cu, Pt, Ti, Ni, Sn, Mo, Co, Pd, and alloys thereof. For example, an APC (Ag-Pd-Cu) alloy can be used. The metal layer 114a may be formed of only at least one of Au, Ag, APC alloy, and Pt. The Au, Ag, APC alloy, and Pt may improve electrical conductivity of the conductive layer 114 and reduce resistance. Therefore, the detection performance of the biosensor 10 can be improved.

In example embodiments, the metal protective layer 114b may include Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO). For example, the metal protective layer 114b may be formed of only ITO or IZO. ITO and IZO have electrical conductivity and are chemically stable, so that the metal layer 114a can be effectively protected from an oxidation-reduction reaction.

For example, the metal protective layer 114b may prevent the metal layer 114a from directly contacting the atmosphere, thereby preventing oxidation of a metal component constituting the metal layer 114a. Accordingly, reliability of an electrical signal sensed by the metal layer 114a may be improved.

The electron transport layer 115 may be disposed on the conductive layer 114. For example, the conductive layer 114 may be directly covered.

The electron transport layer 115 may provide an electron/hole movement path for transferring electrons or holes generated in the oxidation-reduction reaction to the conductive layer 114.

The electron transport layer 115 may include an electron transport material. The electron transport material may include, for example, a material that is oxidized or reduced by receiving electrons/holes generated in an oxidation-reduction reaction of a material to be detected in the enzyme reaction layer 116. Electrons/holes may be transferred through the oxidation or reduction.

In example embodiments, the electron transport material may include Prussian blue. Prussian blue is a blue pigment whose main component is potassium hexacyanoferric(II) iron(III), and may have high oxidizability. When Prussian blue is disposed on the conductive layer 114, the electrical sensitivity of the working electrode 110 may be improved.

In some embodiments, the electron transport layer 115 may further include carbon paste.

The enzyme reaction layer 116 may be disposed on the electron transport layer 115. For example, it may directly contact the upper surface of the electron transport layer 115.

The enzyme reaction layer 116 may be provided as a layer in which a chemical reaction of a substance to be detected included in the sample occurs. The enzyme reaction layer 116 may include an oxidative enzyme or a dehydrogenase that reacts with a substance to be detected.

In exemplary embodiments, the oxidative enzyme is the enzyme reaction layer 116 is glucose oxidase, cholesterol oxidase, lactate oxidase, and ascorbic acid oxidase. acid oxidase) and alcohol oxidase. The dehydrogenase may include at least one of glucose dehydrogenase, glutamate dehydrogenase, lactate dehydronase, and alcohol dehydrogenase.

Therefore, the concentration of glucose, cholesterol, lactate, ascorbic acid, alcohol or glutamic acid can be measured.

For example, when the biosensor 10 is a glucose sensor, the enzyme reaction layer 116 may include glucose oxidase or glucose dehydrogenase.

In some embodiments, the oxidative enzyme or the dehydrogenase may be immobilized through a binder. The binder may include a binder commonly used in the art, and may include, for example, chitosan.

For example, when a sample is injected into the biosensor 10, a detection target material included in the sample may be oxidized by an oxidase or dehydrogenase, and hydrogen peroxide may be formed. The electron transport material (eg, Prussian blue) reduces hydrogen peroxide, and itself can be oxidized. The oxidized electron transport material loses electrons at the electrode surface to which a certain voltage is applied and may be electrochemically oxidized again.

Since the concentration of the sensing target material in the sample is proportional to the amount of current generated in the process of oxidizing the electron transport material, the concentration of the sensing target material can be measured by measuring the amount of current.

The filter layer 117 may be disposed on the enzyme reaction layer 116. For example, it may be directly covered on the upper surface of the enzyme reaction layer 116.

The filter layer 117 may protect the enzyme reaction layer 116 from external physical forces. In addition, it is possible to prevent the oxidative enzyme or dehydrogenase of the enzyme reaction layer 116 from being exposed to the external environment.

The filter layer 117 may pass only the material to be detected in the sample. Accordingly, it is possible to prevent the enzyme reaction layer 116 from being denatured or damaged by substances other than the substance to be detected.

If the filter layer 117 passes a material to be detected, an ion exchange membrane commonly used in the art may be used. The ion exchange membrane may include a cation exchange resin such as a perfluorosulfonic acid resin. For example, the ion exchange membrane may include Nafion.

According to exemplary embodiments of the present invention, a conductive layer 114 is formed on the substrate 100, an electron transport layer 115 is formed on the conductive layer 114, and an enzyme is formed on the electron transport layer 115. By forming the reaction layer 116, the working electrode 110 can be manufactured.

The conductive layer 114 forms a metal film including at least one of Au, Ag, Cu, Pt, Ti, Ni, Sn, Mo, Co, Pd, and alloys thereof on the substrate 100, and then patterning ( patterning).

For the patterning, a patterning method commonly used in the art may be used. For example, photolithography can be used.

When the conductive layer 114 further includes a metal protective layer 114b, the metal layer 114a is first patterned and then a metal protective layer 114b is formed, or ITO (Indium Tin Oxide) or IZO is formed on the metal layer. After the (Indium Zinc Oxide) conductive oxide layer is formed, the metal layer 114a and the metal protective layer 114b may be formed together by patterning the metal layer and the conductive oxide layer together.

In example embodiments, the electron transport layer 115 may be formed by applying a mixture of an electron transport material and a carbon paste on the conductive layer 114.

For the coating, a coating method commonly used in the art may be used, and for example, various printing methods may be used.

The enzyme reaction layer 116 may be formed by, for example, applying a composition obtained by mixing the oxidative enzyme or the dehydrogenase with a binder on the electron transport layer 115 and then drying it.

The reference electrode 120 may be disposed on the substrate 100 to face the working electrode 110 left and right. The reference electrode 120 and the working electrode 110 may be electrically separated. The reference electrode 120 may be provided as a counter electrode for an oxidation-reduction reaction.

The reference electrode 120 may provide a reference value for a current value or a potential value measured by the working electrode 110 during measurement. Using the potential value of the reference electrode 120 as a reference value, the oxidation-reduction reaction of the material to be detected in the working electrode 110 may be specified. In addition, by comparing the reference value of the current value and the current value measured by the working electrode 110, the amount of current purely changed by the sensing target material may be calculated. Accordingly, it is possible to derive the concentration of the material to be detected from the amount of current.

The second conductive layer 124 of the reference electrode 120 may include substantially the same material as the conductive layer 114 of the working electrode 110. Also, a reference material layer 126 may be disposed on the second conductive layer 124 instead of the electron transport layer 115. For example, the reference electrode 120 may be formed by stacking the second conductive layer 124 and the reference material layer 126 on the substrate 100.

The reference material layer 126 may include, for example, Ag/AgCl paste.

In some embodiments, the wiring 140 may be connected to the working electrode 110 and the reference electrode 120, respectively. The first wiring 142 connected to the working electrode 110 and the second wiring 144 connected to the reference electrode 120 may be electrically spaced apart from each other. The wirings 140 may be connected to a driving integrated circuit (IC) chip.

For example, the first wiring 142 may be formed of the same material as the metal layer 114a of the working electrode 110 and the second conductive layer 124 of the reference electrode 120. In some embodiments, the wiring 140 may be integrally formed with the working electrode 110 and the reference electrode 120. For example, by forming a metal film on the substrate 100 and patterning it, the working electrode 110 and the wiring 140 may be formed together.

Electrical signals measured from the working electrode 110 and the reference electrode 120 may be transmitted to the driving IC chip through the wiring 140, and the driving IC chip may calculate the concentration of the component to be measured.

Example 1

A working electrode and a reference electrode were formed on the substrate in the shape shown in FIG. 2.

The working electrode is an APC metal layer with a thickness of about 2000Å and a conductive layer with an IZO metal protective layer with a thickness of 500Å, a carbon paste electrode (including 3wt% of Prussian blue, a thickness of about 10㎛), and an enzyme in which glucose oxidase is fixed with chitosan. The reaction layers were sequentially stacked to prepare.

The reference electrode was formed of Ag/AgCl.

Example 2

A sensing electrode was formed in the same manner as in Example 1 except that the shapes of the working electrode and the reference electrode were changed to the sawtooth shape shown in FIG. 3.

Comparative Example 1

As shown in FIG. 5, a sensing electrode was formed in a structure in which a reference electrode surrounds a circular working electrode. The overall size of the sensing electrode was formed to be the same as the overall size of the sensing electrode of Example 1.

The structure and material of each of the working electrode and the reference electrode were formed in the same manner as in Example 1.

Experimental Example 1: Evaluation of measurement speed according to electrode shape

The current generated from the sample (0.1 mM aqueous solution of glucose) was measured with the biosensors of Examples 1 and 2 and Comparative Example 1, and a time-current graph of FIG. 8 was obtained.

Referring to FIG. 8, in the biosensors of the embodiments, the current value is saturated in about 9 seconds. However, in the biosensor of the comparative example, the current value was not saturated for 10 seconds.

Accordingly, it was confirmed that the sensing speed of the biosensors of the examples was improved compared to the biosensors of the comparative example.

Comparative Example 2

As shown in FIG. 6, a sensing electrode in which the reference electrode and the working electrode have a fork shape was formed. The overall size of the sensing electrode was formed to be the same as the overall size of the sensing electrode of Example 1.

The structure and material of each of the working electrode and the reference electrode were formed in the same manner as in Example 1.

Experimental Example 2: Evaluation of measurement accuracy according to electrode shape

Using the biosensor of Example 2 and Comparative Example 2, the current generated from the sample (0.1 mM glucose aqueous solution) was measured 6 times for each sample, and the average, standard deviation, and relative standard deviation of each current value measured in 60 seconds were calculated. It is shown in Table 1 below.

Average current value (nA; @60 sec) Standard Deviation Relative standard deviation (%) Example 2 48.5 1.8 3.8 Comparative Example 2 48.5 9.4 19.3

Referring to Table 1, the average value of each of the current measurement values of the Example and Comparative Example was 47 and 49 nA, and there was no significant difference. Showed a difference.

Therefore, it was confirmed that the measurement accuracy of the biosensor according to the embodiment is improved by uniform coating of the enzyme reaction layer.

Examples 3 to 5

A sensing electrode was formed in the same manner as in Example 1, except that the shape of the working electrode and the reference electrode was formed larger than that of the reference electrode as shown in FIG. 4. At this time, the area of the working electrode was 3 times (Example 3), 9 times (Example 4) and 12 times (Example 5) of the area of the reference electrode, respectively.

Experimental Example 3: Evaluation of measurement speed according to electrode area

The current generated from the sample (0.1 mM aqueous solution of glucose) was measured with the biosensors of Examples 1 and 3 to 5, and a time-current graph of FIG. 9 was obtained.

Referring to FIG. 9, the biosensors of Examples 3 to 5 in which the area of the working electrode was larger than that of the reference electrode were saturated more rapidly. Therefore, it was confirmed that the sensing speed was further improved.

10: biosensor
100: substrate 110: working electrode
112: first facing surface 114: conductive layer
115: electron transport layer 116: enzyme reaction layer
117: filter layer
120: reference electrode 122: second facing surface
124: second conductive layer 126: reference material layer
130: auxiliary sensor 140: wiring
20: sensing electrode of a comparative example

Claims (16)

Board;
A working electrode disposed on the substrate and including a first opposing surface having an uneven shape; And
And a reference electrode having a second opposite surface facing and spaced apart from the working electrode on the substrate, facing the first facing surface, and having a concave-convex shape,
The concave-convex shape of the first facing surface and the concave-convex shape of the second facing surface do not cross a center line of the working electrode and the reference electrode,
The uneven shape of the first opposing surface and the uneven shape of the second opposing surface do not cross each other along the center line.
The biosensor according to claim 1, wherein the first facing surface and the second facing surface include a convex portion and a concave portion.
The method according to claim 2, wherein the convex portion of the first opposing surface is disposed to face the concave portion of the second opposing surface, and the concave portion of the first opposing surface faces the convex portion of the second opposing surface Placed, biosensor.
The biosensor according to claim 3, wherein a shape of the convex portion and a shape of the concave portion are in a complementary relationship.
The biosensor according to claim 1, wherein the uneven shape is formed on the entire first and second facing surfaces.
delete The biosensor of claim 1, wherein the working electrode and the reference electrode define a sensing electrode, and the total width of the sensing electrode is 0.3 to 5 mm.
The biosensor of claim 1, wherein an area of the working electrode is greater than or equal to an area of the reference electrode.
The biosensor of claim 1, wherein an area of the working electrode is 1 to 15 times the area of the reference electrode.
The method according to claim 1, wherein the working electrode,
A conductive layer disposed on the substrate;
An electron transport layer disposed on the conductive layer; And
A biosensor comprising an enzyme reaction layer disposed on the electron transport layer.
The method of claim 10, wherein the enzyme reaction layer is at least one of glucose oxidase, cholesterol oxidase, lactate oxidase, ascorbic acid oxidase and alcohol oxidase, or glucose dehydrogenase, glutamic acid dehydrogenase, lactate dehydrogenase. And at least one dehydrogenase of alcohol dehydrogenase.
The biosensor of claim 10, wherein the electron transport layer comprises Prussian blue.
The biosensor of claim 10, wherein the conductive layer includes a metal layer and a metal protective layer.
The biosensor of claim 13, wherein the metal layer comprises at least one of Au, Ag, Cu, Pt, Ti, Ni, Sn, Mo, Co, Pd, and alloys thereof.
The biosensor of claim 13, wherein the metal protective layer comprises Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO).
The biosensor of claim 10, wherein the working electrode further comprises a filter layer disposed on the enzyme reaction layer.

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