WO2019212159A1 - Glucose sensor - Google Patents

Abstract

The present invention relates to a glucose sensor. The present invention comprises: a substrate; an electrode part including a reference electrode and a working electrode that are formed on the substrate; an electrode protection/electron transport function part formed on the electrode part as a single layer for protecting the electrode part and performing a function of electron transport; and a glucose reaction part formed on the electrode protection/electron transport function part, in which a relative voltage, which is a potential difference between the reference electrode and the working electrode, is -0.3 V to 0.0 V. The present invention can keep the measurement sensitivity to glucose uniform within an optimum range.

Description

Glucose sensor

The present invention relates to a glucose sensor. More specifically, the present invention relates to a glucose sensor capable of keeping the measurement sensitivity to glucose uniform in an optimal range.

Glucose is a broad source of nutrition for most organisms and is a component that plays a fundamental role in energy supply, carbon storage, biosynthesis, and the carbon skeleton and cell wall formation. A glucose sensor that measures glucose concentration through potentiometric or current measurements. Research is being actively conducted.

Most studies on the glucose sensor are based on the immobilization of enzymes such as glucose oxidase or glucose dehydrogenase, which promote the oxidation of glucose to gluconolactone.

Such glucose sensors may be classified into invasive, which mainly measures glucose contained in blood, and non-invasive, which mainly measures glucose contained in saliva, sweat, and the like.

On the other hand, in the case of non-invasive glucose sensor using a sample of saliva, sweat, etc. of the human body, since the amount of glucose contained in the sample is very small, it is difficult to maintain the measurement sensitivity of the glucose sensor uniformly in the optimum range.

[Prior art document]

[Patent Documents]

(Patent Document 1) Korean Unexamined Patent Publication No. 2001-0110272 (published date: December 12, 2001, name: electrode and glucose analysis electrode containing Pt metal)

An object of the present invention is to provide a glucose sensor capable of maintaining the measurement sensitivity to glucose uniformly in an optimal range.

The glucose sensor according to the present invention for solving the technical problem is formed of a substrate, an electrode unit including a reference electrode and a working electrode formed on the substrate, a single layer formed on the electrode portion to protect the electrode portion and transport electrons An electrode protection / electron transport function and a glucose reaction unit formed on the electrode protection / electron transport function, wherein the relative voltage, which is the potential difference between the reference electrode and the working electrode, is -0.3V to 0.0V. .

In the glucose sensor according to the present invention, the Michaelis-Menten constant (K _M ) is 0.4mM to 12.2mM.

In the glucose sensor according to the present invention, the Michael-less - a ⁷ mM / s ^- maximum reaction velocity (V _max) of menten enzyme reaction rate equation is 3.85 × 10 ^{- 7} mM / s to 6.9 × 10.

In the glucose sensor according to the present invention, the electrode protection / electron transport function portion has a structure in which an electrode protector for protecting the electrode portion and an electron transport function for the electron transport function are mixed.

In the glucose sensor according to the present invention, the electrode protector is characterized in that it comprises carbon (carbon).

In the glucose sensor according to the present invention, the electron transporter is characterized in that it comprises prussian blue.

In the glucose sensor according to the present invention, the electrode portion is gold (Au), silver (Ag), copper (Cu), platinum (Pt), titanium (Ti), nickel (Ni), tin (Ni), molybdenum (Mo ), Cobalt (Co), characterized in that it comprises one or more selected from the group consisting of APC.

In the glucose sensor according to the present invention, the glucose reaction unit is characterized in that it comprises glucose oxidase or glucose dehydrogenase.

The glucose sensor according to the present invention is further characterized by an ion exchange membrane formed on the glucose reaction unit.

In the glucose sensor according to the present invention, the ion exchange membrane is characterized in that it protects the glucose oxidase or the glucose dehydrogenase constituting the glucose reaction part by preventing the penetration of impurity ion components.

According to the present invention, there is provided an effect of providing a glucose sensor capable of keeping the measurement sensitivity to glucose uniformly in an optimal range.

1 is a cross-sectional view of a glucose sensor according to an embodiment of the present invention,

2 is an exemplary plan view of a glucose sensor manufactured according to an embodiment of the present invention,

3 is a view showing a voltage swing test (Voltage Swing Test) results according to the glucose concentration of a substrate in an embodiment of the present invention,

4 is a diagram illustrating a cyclic voltamogram according to a relative voltage according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a calibration curve according to one embodiment of the present invention.

FIG. 6 is a diagram illustrating a Lineweaver-Burk Plot according to one embodiment of the present invention.

Specific structural or functional descriptions of the embodiments according to the inventive concept disclosed herein are provided only for the purpose of describing the embodiments according to the inventive concept. It may be embodied in various forms and is not limited to the embodiments described herein.

Embodiments according to the inventive concept may be variously modified and have various forms, so embodiments are illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments in accordance with the concept of the invention to the specific forms disclosed, it includes all changes, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first or second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another, for example without departing from the scope of the rights according to the inventive concept, and the first component may be called a second component and similarly the second component. The component may also be referred to as the first component.

When a component is said to be "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may exist in the middle. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle. Other expressions describing the relationship between components, such as "between" and "immediately between" or "neighboring to" and "directly neighboring", should be interpreted as well.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described herein, but one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and are not construed in ideal or excessively formal meanings unless expressly defined herein. Do not.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a cross-sectional view of a glucose sensor according to an embodiment of the present invention, Figure 2 is an exemplary plan view of a glucose sensor manufactured according to an embodiment of the present invention.

1 and 2, a glucose sensor according to an embodiment of the present invention includes a substrate 10, an electrode unit 20, an electrode protection / electron transport function unit 30, a glucose reaction unit 50, and an ion The exchange membrane 60, the wiring unit 70, and the temperature sensor 100 are included.

Prior to describing the detailed components of the glucose sensor according to an embodiment of the present invention, the main contents of the present invention will be described first.

First, the enzyme kinetics (Enzyme Kinetics) applied to the glucose sensor according to an embodiment of the present invention will be described.

Equation 1 represents the enzyme reaction equation, Equation 2 represents the Michaelis-Menten equation, Equation 3 represents the Lineweaver-Burk equation, Equation 4 is The Michaelis-Menten constant is shown.

[Equation 1]

[Equation 2]

[Equation 3]

[Equation 4]

In Equations 1 to 4, E is an enzyme, S is a substrate, ES is an enzyme-substrate complex, P is a product, [S] is a concentration of glucose that is a substrate, and K _M is a Michaelis-Menten constant ( Michaelis-Menten Constant, and V _Max is the maximum reaction rate in the Michaelis-Menten enzyme kinetics, in other words, the turnover number, the rate of conversion to the product in unit time.

K _M means the affinity of the enzyme for the substrate. Low K _M means that the substrate-enzyme has a high affinity, in which case the enzyme-substrate complex (ES) state is stable, and high K _M means that the substrate-enzyme has low affinity, in which case product (P) production. This is facilitated.

According to the glucose sensor according to the exemplary embodiment of the present invention, a relative voltage, which is a potential difference between the reference electrode and the working electrode configuring the electrode unit, is -0.3V to 0.0V.

When the relative voltage is within the range of -0.3V to 0.0V, the linearity of the detection signal according to the glucose concentration injected into the glucose sensor according to the embodiment of the present invention is secured and the sensitivity is improved, and the linearity and the sensitivity are improved. The more preferable range of relative voltage for is -0.2V to 0V.

If the relative voltage is less than -0.3 V, the reliability of the sense signal is degraded due to reducing corrosion. In addition, when the relative voltage exceeds 0.0 V, the linearity of the sense signal is not maintained and the deviation increases as the concentration of glucose increases.

For example, in the glucose sensor according to an embodiment of the present invention, the Michaelis-Menten constant (K _M ) may be 0.4mM to 12.2mM.

When the Michaelis-Menten constant (K _M ) satisfies the range of 0.4 mM to 12.2 mM, the linearity of the detection signal according to the glucose concentration is ensured and the sensitivity is improved.

If the Michaelis-Menten constant (K _M ) is less than 0.4 mM, reducing corrosion reduces the reliability of the sense signal. In addition, when the Michaelis-Menten constant K _M exceeds 12.2 mM, the linearity of the sense signal is not maintained.

For example, in a glucose sensor in accordance with one embodiment of the invention, the Michael-less - maximum reaction rate of the enzyme reaction rate menten formula (V _max) is 3.85 × 10 ^{- 7} mM / s to 6.9 × 10 ^-7 mM / can be s.

The maximum reaction velocity (V _max) is 3.85 × 10 ^{- 7} mM / s to 6.9 × 10 ^- if they meet a range of ⁷ mM / s, the linearity of the detection signal corresponding to the glucose concentration is to secure and improve the sensitivity.

The 3.85 × 10 maximum reaction velocity (V _max) ^- When ⁷ mM / s is less than, due to reducing the corrosion decreases the reliability of the detected signal. In addition, the maximum reaction rate (V _max) 6.9 × 10 ^- In the case of more than ⁷ mM / s, but this linearity is not maintained in the detection signal.

The substrate 10 functions to provide a structural base of the components constituting the glucose sensor.

For example, the substrate 10 may be implemented in the form of a base film having a rigid material such as glass or the like and having flexible characteristics. Examples of specific materials that can be applied to the base film when the substrate 10 is implemented to be flexible 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 resins; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymers; Polyolefin-based resins such as polyethylene, polypropylene, cyclo-based or norbornene-structured polyolefins, ethylene-propylene copolymers; Vinyl chloride-based resins; Amide resins such as nylon and aromatic polyamides; Imide resin; Polyether sulfone resin; Sulfone resins; Polyether ether ketone resins; Sulfided polyphenylene resins; Vinyl alcohol-based resins; Vinylidene chloride-based resins; Vinyl butyral resin; Allyl resins; Polyoxymethylene resin; And films composed of thermoplastic resins such as epoxy resins, and the like, and films composed of blends of the above thermoplastic resins may also be used. Moreover, the film of thermosetting resin or ultraviolet curable resin, such as (meth) acrylic-type, urethane type, acrylurethane type, epoxy type, and silicone type, can also be used. Although the thickness of such a transparent optical film can be suitably determined, generally, it can be determined to 1-500 micrometers in consideration of workability, thinness, etc., such as intensity | strength and handleability. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable.

Such a base film may contain a suitable one or more additives. As an additive, a ultraviolet absorber, antioxidant, a lubricant, a plasticizer, a mold release agent, a coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent, etc. are mentioned, for example. The base film may have a structure including various functional layers such as a hard coating layer, an antireflection layer, and a gas barrier layer on one or both surfaces of the film, and the functional layer is not limited to the above, and includes various functional layers depending on the purpose. can do.

In addition, the base film may be surface-treated as needed. Examples of such surface treatment include a plasma treatment, a corona treatment, a dry treatment such as a primer treatment, and a chemical treatment such as an alkali treatment including saponification treatment.

The electrode unit 20 is composed of a plurality of electrodes formed on the substrate 10. The electrode unit 20 senses an electrical signal generated by a reaction between a substance constituting the glucose reaction unit 50, which will be described later, and glucose contained in the substance to be measured. For example, the measurement target material may be saliva, sweat, body fluid, blood, and the like, but is not limited thereto.

For example, as illustrated in FIG. 2, the electrodes constituting the electrode portion 20 correspond to the working electrodes 21-1 and 22-1 and the working electrodes 21-1 and 22-1. And reference electrodes 21-2 and 22-2, and the electrode part 20 includes gold (Au), silver (Ag), copper (Cu), platinum (Pt), and titanium (Ti). ), Nickel (Ni), tin (Ni), molybdenum (Mo), cobalt (Co), may include one or more selected from the group consisting of APC, or an alloy thereof. APC is an Ag-Pd-Cu alloy.

The electrode protection / electron transport function unit 30 is formed on the electrode unit 20 and a portion of the substrate 10 outside the electrode unit 20 to protect the electrodes constituting the electrode unit 20, It performs a function of increasing the electrical sensitivity of the electrode unit 20 through the transport.

For example, the electrode protection / electron transport function unit 30 may have a structure in which an electrode protector that protects the electrode unit 20 and an electron transporter that functions as an electron transporter are mixed.

For example, the electrode protector constituting the electrode protection / electron transport function 30 may include carbon, and the electron transporter may include prussian blue.

Prussian blue included in the electrode protection / electron transport function unit 30 is a component that performs the function of electron transport, and is a blue pigment whose main component is potassium hexacyano iron (II) acid oxide, and has high oxidative property. . If the electrode protection / electron transport function 30 including Prussian blue is formed between the electrode 20 and the glucose reaction unit 50, the sensitivity of the electrode can be improved, but the lower portion of the Prussian blue Located metallic electrode portion 20 may oxidize and corrode. According to an embodiment of the present invention, since the electrode protection / electron transport function unit 30 is configured to include carbon which performs the function of electrode protection through oxidation prevention in addition to Prussian blue which performs the function of electron transport, Corrosion of the electrode part 20 due to Prussian blue included in the electrode protection / electron transport function part 30 can be prevented.

The glucose reaction unit 50 is formed on the electrode protection / electron transport function unit 30 and is a component that reacts with glucose contained in the material to be measured.

For example, the glucose reaction unit 50 may include glucose oxidase or glucose dehydrogenase.

The reaction in the glucose reaction unit 50 and the signal detection principle of the electrode unit 20 will be described as follows.

When a sample, which is the substance to be measured, is injected into the glucose sensor, glucose contained in the sample is oxidized by glucose oxidase or glucose dehydrogenase, and glucose oxidase or glucose dehydrogenase is reduced. At this time, the electron transfer mediator oxidizes glucose oxidase or glucose dehydrogenase, and itself is reduced. The reduced electron transfer mediator loses electrons at the electrode surface subjected to a constant voltage and is oxidized electrochemically again. Since the glucose concentration in the sample is proportional to the amount of current generated during the oxidation of the electron transfer medium, the glucose concentration can be measured by measuring the amount of current.

The ion exchange membrane 60 is formed on the glucose reaction unit 50, and passes only the component to be measured among the substances included in the sample, thereby preventing the penetration of external impurity ion components to prevent the glucose reaction unit 50. Protects glucose oxidase or glucose dehydrogenase. For example, the ion exchange membrane 60 may include Nafion, but this is only one example, and the ion exchange membrane 60 is not limited thereto.

The wiring unit 70 includes electrodes constituting the electrode unit 20 and a plurality of electrical wires formed from the temperature sensor 100. The wiring unit 70 may be connected to a sensing analysis unit that performs a current analysis function through an electrical connection medium such as a flexible printed circuit board (FPCB) (not shown). Although not shown in the drawings, a pad region may be provided at an end of the wiring unit 70, and the FPCB may be bonded to and electrically connected to the pad region.

The temperature sensor 100 is a component that is formed on the substrate 10 to measure the temperature of the environment in which the glucose concentration is measured. That is, the temperature sensor 100 transmits a current corresponding to the temperature to the IC having a current analysis function, and the IC converts the current value received from the temperature sensor 100 according to a set conversion algorithm. Since the measured glucose concentration may vary depending on the temperature, the temperature may be measured together with the glucose concentration, and the glucose concentration may be corrected according to the temperature, or the measured concentration may be matched with the temperature. .

Table 1 shows the reproducibility test results for the glucose sensor according to an embodiment of the present invention, the Michaelis-Menten constant (K _M ) according to the relative voltage, the maximum in the Michaelis-Menten enzyme reaction rate equation. Experimental data of the reaction rate (V _max ).

Relative voltage (V)	0	-0.1	-0.2	-0.3
K M (mM)	0.75	12.19	2.08	0.42
Vmax (mM / s)	3.85 × 10 -7	6.90 × 10 -6	1.58 × 10 -6	5.62 × 10 -7

Referring to Table 1, when the relative voltage satisfies the range of -0.3V to 0.0V, the linearity of the sensing signal according to the concentration of glucose to be detected is secured and the sensitivity is improved, and the relative voltage for securing the linearity and the sensitivity is improved. The more preferable range of is -0.2V to 0V. If the relative voltage is less than -0.3 V, the reliability of the sense signal is degraded due to reducing corrosion. In addition, when the relative voltage exceeds 0.0 V, the linearity of the sense signal is not maintained and the deviation increases as the concentration of glucose increases.

Michaelis-Menten constant (K _M ) may be 0.4mM to 12.2mM. When the Michaelis-Menten constant (K _M ) satisfies the range of 0.4 mM to 12.2 mM, the linearity of the detection signal according to the glucose concentration is ensured and the sensitivity is improved. If the Michaelis-Menten constant (K _M ) is less than 0.4 mM, reducing corrosion reduces the reliability of the sense signal. In addition, when the Michaelis-Menten constant K _M exceeds 12.2 mM, the linearity of the sense signal is not maintained.

Michael Let - maximum reaction velocity (V _max) of menten enzyme reaction rate equation is 3.85 × 10 ^- may be a ^{7 mM / s - 7 mM /} s to 6.9 × 10. The maximum reaction velocity (V _max) is 3.85 × 10 ^- if they meet a range of ⁷ mM / s to 6.9 × 10 ^-7 mM / s, the linearity of the detection signal corresponding to the glucose concentration is to secure and improve the sensitivity. The 3.85 × 10 maximum reaction velocity (V _max) ^- When ⁷ mM / s is less than, due to reducing the corrosion decreases the reliability of the detected signal. In addition, when the maximum reaction rate (V _max ) exceeds 6.9 × 10 ⁻⁷ mM / s, the linearity of the sense signal is not maintained.

FIG. 3 is a diagram illustrating a voltage swing test result according to a glucose concentration, which is a substrate, in which relative voltages are set to 0 V and −0.1 for evaluation of two glucose sensor specimens, respectively. As a result of measuring the concentration of glucose by adjusting to V, the effect of improving the sensitivity at the evaluation at -0.1V was confirmed. D1 and D2 of FIG. 3 represent detection results of the specimen in which the relative voltage is adjusted to -0.1V, and D1 'and D2' represent detection results of the specimen in which the relative voltage is 0.0V.

4 is a diagram illustrating a cyclic voltamogram according to a relative voltage, in which a peak value of a reduction potential peak of a Prussian Blue electron transport chain is 0V. It can be confirmed that it exists between and -0.1V, and by fixing the phase voltage to -0.1V, it is possible to convert most of Prussian blue existing in oxidation form to reduction form. This may improve the sensitivity of the glucose sensor.

FIG. 5 is a diagram illustrating a calibration curve according to an embodiment of the present invention, and shows a result of evaluating relative voltages for each glucose concentration. FIG. 6 is an embodiment of the present invention. , Lineweaver-Burk plot, a graph obtained by taking the inverse of the result of a calibration curve, Michaelis-Menten constant (K _M ) is the intercept, the maximum reaction rate (Vmax ) Is the slope.

As described in detail above, according to the present invention, there is an effect of providing a glucose sensor capable of maintaining the measurement sensitivity to glucose uniformly in an optimal range.

[Description of the code]

10: Substrate

20: electrode part

21-1, 22-1: working electrode

21-2, 22-2: reference electrode

30: electrode protection / electron transport function

50: glucose reaction part

60: ion exchange membrane

70: wiring section

100: temperature sensor

Claims (10)

1. Board;

   An electrode unit including a reference electrode and an operation electrode formed on the substrate;

   An electrode protection / electron transport function unit formed on the electrode unit as a single layer and protecting the electrode unit and performing a function of electron transport; And

   It comprises a glucose reaction portion formed on the electrode protection / electron transport function,

   A relative voltage that is the potential difference between the reference electrode and the working electrode is -0.3V to 0.0V.
2. The method of claim 1,

   Michaelis-Menten constant (K _M ) is a glucose sensor, 0.4mM to 12.2mM.
3. The method of claim 1,

   Michael-less-menten maximum reaction velocity (V _max) of the enzyme reaction rate equation was 3.85 × 10 ^{- 7} is mM / s to 6.9 × 10 ^-7 mM / s, the glucose sensor.
4. The method of claim 1,

   And said electrode protection / electron transport function part has a structure in which an electrode protector for protecting said electrode part and an electron transporter functioning as said electron transport are mixed.
5. The method of claim 4, wherein

   The electrode protector comprises a carbon, characterized in that the glucose sensor.
6. The method of claim 4, wherein

   Wherein said electron transporter comprises prussian blue.
7. The method of claim 1,

   The electrode part is made of gold (Au), silver (Ag), copper (Cu), platinum (Pt), titanium (Ti), nickel (Ni), tin (Ni), molybdenum (Mo), cobalt (Co), and APC. A glucose sensor, characterized in that it comprises one or more selected from the group consisting of.
8. The method of claim 1,

   The glucose reaction unit comprises a glucose oxidase or glucose dehydrogenase, glucose sensor.
9. The method of claim 8,

   It further comprises an ion exchange membrane formed on the glucose reaction unit, glucose sensor.
10. The method of claim 9,

    Wherein the ion exchange membrane protects glucose oxidase or glucose dehydrogenase constituting the glucose reaction unit by preventing penetration of impurity ion components.

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