KR102463324B1 - Bio Sensor - Google Patents

Abstract

The present invention relates to a biosensor. Specifically, the biosensor according to an embodiment of the present invention includes a substrate, an electrode unit formed on one surface of the substrate, an electron transfer unit formed on the electrode unit, a glucose reaction unit formed on the electron transfer unit, and the glucose and an electrolyte supply layer formed on the reaction unit, wherein the electrolyte supply layer includes an electrolyte including anions and cations.

Description

Bio Sensor

The present invention relates to a biosensor. More specifically, the present invention relates to a glucose sensor capable of measuring a glucose concentration.

Glucose is a broad source of nutrients for most organisms, and as a component that plays a basic role in energy supply, carbon storage, biosynthesis, and carbon skeleton and cell wall formation, a glucose sensor that measures the concentration of glucose through potentiometric or current measurement research is being actively carried out.

Most studies of glucose sensors are based on the immobilization of enzymes such as glucose oxidase or glucose dehydrogenase that catalyze the oxidation of glucose to gluconolactone.

Such a glucose sensor may be divided into an invasive type that mainly measures glucose contained in blood and a non-invasive type that mainly measures glucose contained in saliva, sweat, and the like.

In the case of a non-invasive glucose sensor, it is attached to the human body to analyze and monitor a biological solution containing saliva or sweat. At this time, electrolytes contained in the body fluid act as factors that interfere with accurate sensing, and in addition, there is a problem in that the concentration of electrolyte varies for each measurement, so that there is a problem that there is a deviation for each subject when measuring glucose.

Therefore, the following describes a glucose sensor with improved accuracy by minimizing the influence from the electrolyte.

Laid-Open Patent Publication No. 10-2006-0134137

The present invention relates to a biosensor, particularly a glucose sensor, and an object of the present invention is to provide a glucose sensor with higher accuracy including an electrolyte supply layer composed of an electrolyte containing both positive and negative ions.

The present invention relates to a biosensor. Specifically, the biosensor according to an embodiment of the present invention includes a substrate, an electrode unit formed on one surface of the substrate, an electron transfer unit formed on the electrode unit, a glucose reaction unit formed on the electron transfer unit, and the glucose and an electrolyte supply layer formed on the reaction unit, wherein the electrolyte supply layer includes an electrolyte including anions and cations.

The biosensor according to an embodiment of the present invention can increase the accuracy of the glucose sensor by filtering not only the anion component included in the body fluid but also the anion component.

1 is a cross-sectional view of a glucose sensor according to an embodiment of the present invention.
2 exemplarily shows an electrode arrangement of a glucose sensor electrode unit according to an embodiment of the present invention.
3 shows a comparison between the performance of a glucose sensor according to an embodiment of the present invention and that of a conventional glucose sensor.

The specific structural or functional description of the embodiments according to the concept of the present invention disclosed in this specification is only illustrated for the purpose of explaining the embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention are It may be implemented in various forms and is not limited to the embodiments described herein.

Since the embodiments according to the concept of the present invention may have various changes and may have various forms, the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes all modifications, 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 elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another, for example without departing from the scope of the inventive concept, a first component may be termed a second component and similarly a second component A component may also be referred to as a first component.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is mentioned that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle. Other expressions describing the relationship between elements, such as "between" and "immediately between" or "neighboring to" and "directly adjacent to", etc., should be interpreted similarly.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or combination thereof described herein exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or 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 to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present specification. does not

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

A biosensor is a system that converts information into a recognizable useful signal, such as color, shape, and electrical signal, by using a biological element or mimicking a biological element when obtaining information from a measurement object.

The biosensor is composed of a sensor matrix made of a biosensing material or biomimetic sensing material capable of selectively recognizing a target material and a signal converter that transmits a signal generated during the reaction. As a sensor matrix, enzymes, antibodies, antigens, membranes, receptors, cells, tissues, microDNA, etc. are used, and as a signal conversion method, electrochemistry, color development, optics, fluorescence, piezoelectricity, etc. are used.

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

Referring to FIG. 1 , a glucose sensor according to an embodiment of the present invention includes a substrate 10 , an electrode unit 20 , an electron transfer unit 30 , a glucose reaction unit 40 , an electrolyte supply layer 50 , and wiring. part 70 and a temperature sensor 100 .

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

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

For example, the substrate 10 may have a hard material such as glass or may be implemented in the form of a base film having flexible characteristics. When the substrate 10 is implemented to be flexible, examples of specific materials that can be applied to the base film include polyester-based resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; Cellulose resins, such as a diacetyl cellulose and a triacetyl cellulose; polycarbonate-based resin; acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrenic resins such as polystyrene and acrylonitrile-styrene copolymer; polyolefin-based resins such as polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, and an ethylene-propylene copolymer; vinyl chloride-based resin; amide-based resins such as nylon and aromatic polyamide; imide-based resin; polyether sulfone-based resin; sulfone-based resins; polyether ether ketone resin; sulfide polyphenylene-based resin; vinyl alcohol-based resin; vinylidene chloride-based resin; vinyl butyral-based resin; allylate-based resin; polyoxymethylene-based resins; and a film composed of a thermoplastic resin such as an epoxy-based resin, and a film composed of a blend of the above-mentioned thermoplastic resins can also be used. In addition, a film made of a thermosetting resin or ultraviolet curable resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone may be used. The thickness of such a transparent optical film may be appropriately determined, but in general, in consideration of workability such as strength and handling properties, thin layer properties, and the like, it may be determined to be 1 to 500 μm. In particular, 1-300 micrometers is preferable, and 5-200 micrometers is more preferable.

Such a base film may contain one or more suitable additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The base film may have a structure including various functional layers such as a hard coating layer, an anti-reflection layer, and a gas barrier layer on one or both sides of the film, and the functional layer is not limited to the above, and includes various functional layers depending on the use can do.

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

The electrode unit 20 includes a plurality of electrodes formed on the substrate 10 . The electrode unit 20 detects an electrical signal generated by a reaction between a substance constituting the glucose reaction unit 40, which will be described later, and glucose included in the measurement target material. For example, the measurement target material may be human saliva, sweat, body fluid, blood, etc., but is not limited thereto.

For example, the electrode part 20 is not particularly limited as long as it is a conductive material. The electrode part 20 is, for example, gold (Au), silver (Ag), copper (Cu), platinum (Pt), titanium (Ti), nickel (Ni), tin (Ni), molybdenum (Mo), It may include one or more selected from the group consisting of cobalt (Co) and APC, or an alloy thereof. APC is an Ag-Pd-Cu alloy.

The electrode part 20 may be formed on the substrate 10 by screen printing, physical vapor deposition or etching, or attaching a conductor tape.

The electron transfer unit 30 is formed on the electrode unit 20 and a partial region of the substrate 10 outside the electrode unit 20 . The electron transfer unit 30 is reduced by redox reaction with the enzyme reduced by reaction with glucose, and the electron transfer medium in the reduced state thus formed generates a current on the surface of the electrode to which the oxidation potential is applied.

The electron transport unit 30 may include an electron transport medium, for example, the electron transport medium is hexaamineruthenium (III) chloride, potassium ferricyanide, potassium ferro Cyanide (potassium ferrocyanide), dimethyl ferrocene (DMF), ferricinium (ferricinium), ferrocene monocarboxylic acid (FCOOH), 7,7,8,8, -tetracyanoqui Nodimethane (7,7,8,8-tetracyanoquino-dimethane (TCNQ)), tetrathia fulvalene (TTF) methyl acidinium (NMA+)), tetrathiatetracene (TTT), N-methylphenazinium (NMP+), hydroquinone, 3-dimethylaminobenzoic acid (3-dimethylaminobenzoic acid ( MBTHDMAB)), 3-methyl-2-benzothiozolinone hydrazone, 2-methoxy-4-allylphenol (2-methoxy-4-allylphenol), 4-aminoantipyrine ( 4-aminoantipyrin (AAP)), dimethylaniline, 4-aminoantipyrene, 4-methoxynaphthol, 3,3',5,5'-tetramethylbenzidine ( 3,3',5,5'-tetramethyl benzidine (TMB)), 2,2-azino-di-[3-ethyl-benzthiazoline sulfonate] (2,2-azino-di-[3-ethyl- benzthiazoline sulfonate]), o-dianisidine, o-toluidine, 2,4-dichlorophenol (2,4-dichl orophenol), 4-aminophenazone, benzidine, Prussian blue, bipyridine-osmium complex compound, etc. may be used. In addition, the electron transport unit 30 may be used by mixing the metal-containing complex with thionine or a derivative thereof.

In an additional embodiment, the electron transfer unit 30 may serve to protect the electrode unit 20 . For example, the electron transfer unit 30 may have a structure in which an electrode protector that protects the electrode unit 20 and an electron transfer medium that functions to transfer electrons are mixed. Here, in order to protect the electrode, the electron transfer unit 30 may further include an electrode protection material.

For example, Prussian blue included in the electron transport unit 30 is a component that performs an electron transport function, and is a blue pigment containing iron (III) potassium hexacyanoferrate (II) as a main component, and has high oxidation properties. . If the electron transfer unit 30 containing Prussian blue is formed between the electrode unit 20 and the glucose reaction unit 40, the sensitivity of the electrode can be improved, but a metallic electrode located under the Prussian blue color. The portion 20 may be oxidized and corroded.

Accordingly, in an additional embodiment of the present invention to prevent oxidation of the electrode part 20 to protect the electrode, the electron transport unit 30 may further include an electrode protection material together with the electron transport medium. In a specific example, the electrode protection material may be carbon.

The glucose reaction unit 40 is formed on the electron transfer unit 30 and may include an oxidoreductase that is reduced by reacting with glucose contained in the measurement target material. Here, the reduced enzyme reacts with the electron transfer mediator of the electron transfer unit 30 to quantify glucose.

For example, the glucose reaction unit 40 is flavin adenine dinucleotide-glucose dehydrogenase (FAD-GDH), nicotinamide adenine dinucleotide-glucose dehydrogenase (nicotinamide adenine dinucleotide-) glucose dehydrogenase, NAD-GDH), pyrroloquinoline quinone-glucose dehydrogenase (PQQ-GDH), and glucose oxidase (GOx).

A reaction in the glucose reaction unit 40 and a signal sensing principle of the electrode unit 20 will be exemplarily described as follows.

[Scheme 1]

(1) Glucose + GOx-FAD → Gluconic acid + GOx-FADH- ₂

(2) GOx-FADH ₂ + electron transport mediator (oxidized state) → GOx-FAD + electron transport mediator (reduced state)

In Scheme 1, GOx represents glucose oxidase, and GOx-FAD and GOx-FADH ₂ represent the oxidation state and reduction state of flavin adenine dinucleotide (FAD), which is an active site of glycooxidase, respectively.

As shown in Scheme 1 above, (1) first, glucose in blood is oxidized to gluconic acid by the catalytic action of glycooxidase. At this time, FAD, the active site of glycooxidase, is reduced to FADH ₂ . ( ₂ ) Thereafter, the reduced FADH ₂ is oxidized to FAD through a redox reaction with the electron transport mediator, and the electron transport mediator is reduced.

The electron transport medium in the reduced state thus formed diffuses to the electrode surface. At this time, the current generated by applying the oxidation potential of the electron transport medium in the reduced state to the surface of the working electrode is measured. Since the glucose concentration in the sample is proportional to the amount of current generated in the process of oxidation of the electron transport medium, the glucose concentration can be calculated by measuring the amount of current.

The electrolyte supply layer 50 is formed on the glucose reaction unit 40 . Materials included in the sample are not only glucose, but may contain various electrolytes. Specifically, electrolytes contained in the body include Na+, Cl-, NH4+, K+, Mg2+, Ca2+, and the like. These ions need to be removed because they cause noise when measuring glucose.

Accordingly, the electrolyte supply layer 50 according to an embodiment of the present invention may include an electrolyte. And the electrolyte supply layer 50 may include both positive and negative ions.

The anion included in the electrolyte supply layer 50 according to an embodiment of the present invention is a strongly acidic sulfonic acid group (-SO3-), a phosphoric acid group (-PO3-), a weakly acidic carboxylic acid group (-COO-) or Nafion (Nafion). ) may be used.

In addition, as the cation supplied to the electrolyte according to an embodiment of the present invention, a strongly basic quaternary ammonium group (-NR3+) is mainly used, and in specific examples of use, PPG-bis(2-aminopropyl ether)Mn4000 and PPG-bis(2 -aminopropyl ether)Mn230 and TMP-PPG-amine ether can be used.

As a result, since the electrolyte supply layer contains both positive and negative ions, the accuracy of the sensor can be improved by removing both the positive and negative electrolytes contained in the body fluid.

2 exemplarily shows the electrode arrangement of the glucose sensor electrode unit according to an embodiment of the present invention.

As illustrated in FIG. 2 , the electrode unit 20 may include a plurality of electrodes. The plurality of electrodes may include at least one working electrode 21-1 and 22-1 and at least one reference electrode 21-2 and 22-2. In addition, the working electrodes 21-1 and 22-1 and the reference electrodes 21-2 and 22-2 may be disposed to correspond to each other.

The plurality of poles constituting the electrode part 20 are gold (Au), silver (Ag), copper (Cu), platinum (Pt), titanium (Ti), nickel (Ni), tin (Ni), and 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.

In addition, the temperature sensor 100 for measuring the temperature of the glucose concentration measurement environment together with the electrode part 220 may be formed on the substrate 210 .

In addition, the plurality of electrodes and the temperature sensor 100 may be connected to a glucose concentration calculating unit (not shown) through the wiring unit 70 .

The wiring unit 70 includes electrodes constituting the electrode unit 20 and a plurality of electrical wirings extending from the temperature sensor 100 . The wiring unit 70 may be connected to a sensing/analyzing means for performing a current analysis function through an electrical connection medium such as a flexible printed circuit board (FPCB) (not shown). Although not shown in the drawing, a pad area may be provided at the end of the wiring unit 70 , and the FPCB may be attached to the pad area to be electrically connected.

The temperature sensor 100 is formed on the substrate 10 to measure the temperature of the environment in which the glucose concentration is measured. The temperature sensor 100 may sense the temperature of the glucose concentration measurement environment and transmit it to the glucose concentration calculation unit. Here, the glucose concentration calculation unit is ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays, processors), controllers ( controllers), micro-controllers, microprocessors, and other electrical units for performing functions.

The glucose concentration calculating unit may consider the temperature transmitted from the temperature sensor 100 while calculating the glucose concentration based on the amount of current transmitted from the electrode unit 20 . In a specific embodiment, since the measured glucose concentration may have a deviation depending on the temperature, the calculated glucose concentration may be corrected according to the temperature. For example, the correction of the glucose concentration may be performed through a table of correction values according to a preset temperature.

3 shows a comparison result of glucose sensor performance when the electrolyte supply layer uses an electrolyte containing both cations and anions and when an electrolyte containing only cations is used.

Specifically, in FIG. 3, when there is no electrolyte supply layer in the biosensor under the same conditions, when there is only an anion electrolyte supply layer, when there is only an electrolyte supply layer of cations, and when there is an electrolyte supply layer in which both cations and anions are present shows each current sensing result.

As shown in FIG. 3 , when the biosensor does not have an exchange membrane for filtering the electrolyte in the body fluid because there is no electrolyte supply layer, it can be confirmed that the current sensed value has a large degree of dispersion. And, in the case of a biosensor having an electrolyte supply layer having only negative ions or positive ions, it is better than the case without an exchange membrane, but it can be confirmed that an error occurs in the current sensing value.

And finally, as an embodiment of the present invention, when the biosensor includes an electrolyte supply layer containing both positive and negative ions, the dispersion of current sensing values is small compared to other experimental examples, and as a result, the sensing error is relatively It can be confirmed that it is written as .

As a result, the glucose sensor according to an embodiment of the present invention uses an electrolyte supply layer including positive and negative ions to reduce the influence of electrolytes in the body, thereby eliminating measurement bias between subjects and enabling linear sensing according to concentration. There is this.

10: substrate
20: electrode part
21-1, 22-1: working electrode
21-2, 22-2: reference electrode
30: electron transfer unit
40: glucose reaction unit
50: electrolyte supply layer
70: wiring part
100: temperature sensor

Claims (10)

Board;
an electrode part formed on one surface of the substrate;
an electron transfer unit formed on the electrode unit;
a glucose reaction unit formed on the electron transfer unit; and
It includes an electrolyte supply layer formed on the glucose reaction unit,
The electrolyte supply layer includes an electrolyte containing anions and cations,
The anion includes at least one of a sulfonic acid group (-SO3-) or a phosphoric acid group (-PO3-)
biosensor. delete According to claim 1,
The cation includes a quaternary ammonium group (-NR3+)
biosensor. According to 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. comprising at least one selected from the group consisting of
biosensor. According to claim 1,
The electron transfer unit includes an electron transfer medium
biosensor. 6. The method of claim 5,
The electron transport medium is hexaamineruthenium (III) chloride (hexaammineruthenium (III) chloride), potassium ferricyanide, potassium ferrocyanide, dimethyl ferrocene (DMF), ferriciny ferricinium, ferrocene monocarboxylic acid (FCOOH), 7,7,8,8,-tetracyanoquinodimethane (7,7,8,8-tetracyanoquino-dimethane (TCNQ)) , tetrathia fulvalene (TTF), nickel locene (nickelocene (Nc)), N-methyl acidinium (NMA+), tetrathiatetracene (TTT)), N-methylphenazinium (NMP+), hydroquinone, 3-dimethylaminobenzoic acid (MBTHDMAB), 3-methyl-2-benzothiozolinone hydrazone ( 3-methyl2-benzothiozolinone hydrazone), 2-methoxy-4-allylphenol (2-methoxy-4-allylphenol), 4-aminoantipyrin (AAP), dimethylaniline (dimethylaniline), 4-aminoanti Pyrene (4-aminoantipyrene), 4-methoxynaphthol (4-methoxynaphthol), 3,3',5,5'-tetramethylbenzidine (3,3',5,5'-tetramethyl benzidine (TMB)), 2 ,2-azino-di-[3-ethyl-benzthiazoline sulfonate] (2,2-azino-di-[3-ethyl-benzthiazoline sulfonate]), o-dianisidine, o-toluidine ( o-toluidine), 2,4-dichlorophenol (2,4-dichlorophenol), 4-aminophenazone (4-amino phena) zone), benzidine, Prussian blue, or at least one of a bipyridine-osmium complex compound
biosensor. 6. The method of claim 5,
The electron transfer unit further comprises a material for electrode protection
biosensor. According to claim 1,
Further comprising a temperature sensor for measuring the temperature of the glucose measurement environment
biosensor. 9. The method of claim 8,
Further comprising a glucose concentration calculator for calculating a glucose concentration based on the amount of current generated by the electrode
biosensor. 10. The method of claim 9,
The glucose concentration calculation unit corrects the glucose concentration calculation based on the temperature measurement value transmitted from the temperature sensor.
biosensor.

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