KR102617965B1 - Electrical conductivity sensor and method for manufacturing thereof - Google Patents

Abstract

The present invention includes: a first substrate, a second substrate on the first substrate, a first electrode on the first substrate made of a sensitive material having different impedance depending on the concentration of the target material in the analysis sample; and a second electrode on the first substrate, spaced apart from the first electrode and made of a conductive material, wherein the second substrate is configured to expose the first electrode and the second electrode, and between the first electrode and the second electrode. An electrical conductivity sensor with an impedance deviation within 5% within 10 seconds from the time of electrical conductivity measurement, a method for measuring electrical conductivity using the same, a method for manufacturing the same, and an electrical conductivity measuring device including the same are provided.

Description

Electrical conductivity sensor and method of manufacturing the same {ELECTRICAL CONDUCTIVITY SENSOR AND METHOD FOR MANUFACTURING THEREOF}

The present invention relates to electrical conductivity sensors and methods of manufacturing same.

Electrical conductivity is used as a measure for measuring the concentration of ions that can move in an aqueous solution.

Electrical conductivity sensors usually have at least two electrodes and are designed to measure the electrical conductivity or resistance of the aqueous solution between the electrodes by measuring the current or voltage between at least two electrodes in contact with the aqueous solution.

The technology behind the invention has been written to facilitate easier understanding of the invention. It should not be understood as an admission that matters described in the technology underlying the invention exist as prior art.

The inventors of the present invention found that, in the case of a two-electrode conductivity sensor, a polarization phenomenon occurs due to numerous interfaces of the electrode material or defects in the deposition of the electrode material generated during the process of depositing the electrode material (e.g., gold) on the substrate, thereby reducing the conductivity. It was recognized that errors occurred in measurement.

Furthermore, the inventors of the present invention were able to confirm that coating the electrode of the electrical conductivity measurement sensor of the present invention with a non-conductive polymer had the effect of significantly reducing the impedance deviation over time compared to before the polymer treatment.

Furthermore, the inventors of the present invention confirmed that before measuring electrical conductivity, conditioning the electrode by immersing it in a conditioning solution according to various embodiments of the present invention has the effect of significantly reducing the impedance deviation over time compared to before conditioning. I was able to.

In other words, it was confirmed that coating the electrode surface in contact with the analysis sample with a non-conductive polymer or conditioning the electrode surface reduced the impedance deviation over time, making it possible to measure electrical conductivity with higher accuracy.

Accordingly, the problem to be solved by the present invention is to provide an electrical conductivity sensor and a manufacturing method thereof that minimize the impedance (ohm) deviation from the point of conductivity measurement to a specific point in time.

Another problem to be solved by the present invention is to provide an electrical conductivity measurement device including the above-described electrical conductivity sensor.

The problems of the invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

In order to solve the problems described above, an electrical conductivity sensor including a substrate according to an embodiment of the present invention is provided. At this time, the electrical conductivity sensor includes a first substrate, a second substrate on the first substrate, a first electrode on the first substrate made of a sensitive material having different impedance depending on the concentration of the target material in the analysis sample; and a second electrode on the first substrate, spaced apart from the first electrode and made of a conductive material, wherein the second substrate is configured to expose the first electrode and the second electrode, and between the first electrode and the second electrode. It is an electrical conductivity sensor whose impedance deviation within 10 seconds from the time of electrical conductivity measurement is within 5%.

According to a feature of the present invention, the second substrate may have a space surrounding the first electrode and the second electrode to contain the analysis sample.

According to another feature of the present invention, each of the first electrode and the second electrode may further include a non-conductive polymer layer on its uppermost surface facing the first electrode and the second electrode.

According to another feature of the present invention, the thickness of the non-conductive polymer layer may be 10 nm to 100 μm thick.

According to another feature of the present invention, the non-conductive polymer is an electrical insulating material, including sulfonated tetrafluoroethylene based fluoropolymer-copolymer (Nafion), polyvinylidene fluoride (PVDF), poly(N-isopropylacrylamide) (pnipam), poly(N-isopropylmethacrylamide)(PNIPMAm), poly(vinylpolypyrrolidone)(PVP), polytetrafluoroethylene(PTFE), polypropylene(PP), polystyrene(PS), polycarbonate(PC), poly(methyl methacrylate)(PMMA), Poly(hydroxyethyl) methacrylate)(polyHEA), poly(vinyl acetate)(PVAc), poly(methyl methacrylate)(PMA), phosphino-carboxylic acid(PCA), polybutylene(PB), poly(ethylene oxide)(PEO), polyethersulfone (PES) , Nylon 66, polynorbornene, polyethylene (PE), polyvinyl chloride (PVC), Teflon, and Mylar.

According to another feature of the present invention, the surface roughness of the surface of the non-conductive polymer layer in contact with the analysis sample may be 10 nm to 30 nm.

According to another feature of the present invention, the electrical conductivity sensor further includes a conditioning solution container, and the conditioning solution container may be configured to receive the first electrode and the second electrode in the conditioning solution.

According to another feature of the present invention, the conditioning solution is a composition having a pH of 4 to 9 and an osmotic pressure of 0 to 400 mOsm, comprising distilled water, sodium chloride, sodium hyaluronate, and carboxylic acid contained in commercially available artificial tears (eye drops). It may contain at least one of methyl cellulose, sodium edetate hydrate, potassium chloride, hydrochloric acid, sodium hydroxide, and magnesium chloride. That is, the conditioning solution according to another feature of the present invention may be artificial tears.

Furthermore, the conditioning solution contains benzoic acid, sodium benzoate, paraoxybenzomethyl, ethyl paraoxybenzoate, propyl paraoxybenzoate, butyl paraoxybenzoate, sorbic acid, potassium sorbate, sodium sorbate, chlorobutanol, and benzalkonium chloride as preservatives. , benzethonium chloride, phenol, cresol, and chlorocresol may be further included.

According to another feature of the present invention, the electrical conductivity sensor may further include a temperature sensor that measures the temperature of the analysis sample on the exposed portion of the first substrate.

According to another feature of the present invention, the electrical conductivity sensor may further include moisture absorbing paper covering the exposed top of the first electrode, the second electrode, and the first substrate.

According to another feature of the present invention, the second substrate is configured to cover the upper part of the space surrounding the first electrode and the second electrode to contain the analysis sample, and to allow the analysis sample to flow into the space by capillary action. , one side of the space may further include two or more microfluidic channels.

According to another feature of the present invention, the second substrate is configured to cover the upper part of the space surrounding the first electrode and the second electrode so that the analysis sample can be contained, but only covers the upper part of the first electrode and the second electrode. One side of the space is open so that the analysis sample flows into the space through capillary action, and may further include another microfluidic channel on the other side of the space.

According to another feature of the present invention, the first electrode or the second electrode may include a carbon electrode.

In order to solve the problems described above, a method of measuring electrical conductivity using an electrical conductivity sensor according to another embodiment of the present invention is provided. The measurement method includes placing an analysis sample on an electrical conductivity sensor, measuring the impedance of the first electrode and the second electrode, and determining the electrical conductivity of the analysis sample based on the impedance.

In order to solve the problems described above, a method of manufacturing an electrical conductivity sensor according to another embodiment of the present invention is provided. The manufacturing method includes disposing a first electrode and a second electrode on a first substrate, but disposing the second electrode to be spaced apart from the first electrode, disposing a second substrate on the first substrate, but disposing the second electrode Constructing a space surrounding the first electrode and the second electrode to contain the analysis sample in contact with the first electrode and the second electrode, and ensuring that the impedance (ohm) deviation within 10 seconds from the time of measuring the electrical conductivity is less than 5%. Preferably, it includes the step of disposing a non-conductive polymer layer facing the first electrode and the second electrode on the first electrode and the second electrode.

According to the features of the present invention, the thickness of the non-conductive polymer layer may be 10 nm to 100 μm thick.

According to another feature of the present invention, the non-conductive polymer is an electrical insulating material, such as sulfonated tetrafluoroethylene based fluoropolymer-copolymer (Nafion), polyvinylidene fluoride (PVDF), poly(N-isopropylacrylamide) (pnipam), poly(N-isopropylmethacrylamide) (PNIPMAm), poly(vinylpolypyrrolidone)(PVP), polytetrafluoroethylene(PTFE), polypropylene(PP), polystyrene(PS), polycarbonate(PC), poly(methyl methacrylate)(PMMA), Poly(hydroxyethyl methacrylate)(polyHEA), poly(vinyl acetate)(PVAc), poly(methyl methacrylate)(PMA), phosphino-carboxylic acid (PCA), polybutylene (PB), poly(ethylene oxide)(PEO), polyethersulfone (PES), Nylon 66, polynorbornene, It may be at least one of polyethylene (PE), polyvinyl chloride (PVC), Teflon, and Mylar.

According to another feature of the present invention, the method of disposing the non-conductive polymer layer includes electrochemical deposition of the non-conductive polymer, sputtering, printing, chemical vapor deposition, and chemical vapor deposition using an initiator ( It may be using at least one method among initiated chemical vapor deposition, spray, dip coating, and sol-gel coating.

In order to solve the problems described above, a method of manufacturing an electrical conductivity sensor according to another embodiment of the present invention is provided. The manufacturing method includes disposing a first electrode and a second electrode on a first substrate, but disposing the second electrode to be spaced apart from the first electrode, disposing a second substrate on the first substrate, but disposing the second electrode for analysis. Constructing a space surrounding the first electrode and the second electrode so that the sample can be contained in contact with the first electrode and the second electrode, and ensuring that the impedance (ohm) deviation within 10 seconds from the time of measuring the electrical conductivity is within 5%. , including immersing the first electrode and the second electrode in a conditioning solution container containing a conditioning solution.

In order to solve the problems described above, an electrical conductivity measuring device according to another embodiment of the present invention is provided. The measuring device includes an electrical conductivity sensor according to various embodiments of the present invention, an impedance measurement unit configured to measure impedance, and an impedance measurement unit connected to one end of the first electrode and the second electrode of the electrical conductivity sensor, respectively. and includes an output unit configured to output electrical conductivity based on impedance.

Specific details of other embodiments are included in the detailed description and drawings.

The present invention reduces the surface roughness of the electrode surface with a non-conductive polymer coating, thereby reducing the deviation of the impedance and signal instability measured when measuring conductivity.

Furthermore, the electrical conductivity sensor of the present invention can achieve the effect of reducing the surface roughness of the electrode surface by being immersed in a conditioning solution before product storage and use, thereby reducing the deviation of the impedance and signal instability measured when measuring conductivity. It has an effect.

Accordingly, the present invention can improve the accuracy and reliability of conductivity measurement as an electrical conductivity sensor, and has the effect of providing various information in measurement fields such as water quality sensors, pH sensors, osmotic pressure sensors, and dissolved oxygen sensors. there is.

1A to 1C exemplarily illustrate an electrical conductivity sensor and its configuration according to an embodiment of the present invention.
2A to 2B exemplarily illustrate an electrical conductivity sensor including a non-conductive polymer layer and its configuration according to another embodiment of the present invention.
3A to 3B exemplarily illustrate an electrical conductivity sensor including a conditioning solution container and its configuration according to another embodiment of the present invention.
4 to 7 exemplarily illustrate electrical conductivity sensors to which components according to various embodiments of the present invention are added.
Figure 8 exemplarily illustrates an electrical conductivity measurement procedure according to various embodiments of the present invention.
9A to 9B exemplarily illustrate procedures for manufacturing an electrical conductivity sensor according to various embodiments of the present invention.
10A to 10B show performance evaluation results of conditioned electrical conductivity sensors according to various embodiments of the present invention.
11A to 11B show enlarged images of the electrode surface on which the non-conductive polymer layer is disposed according to various embodiments of the present invention.
Figures 12a and 12b show the results of measuring surface roughness using an atomic force microscope for an electrode surface on which a non-conductive polymer layer is not disposed or on an electrode surface on which a non-conductive polymer layer is disposed according to various embodiments of the present invention.

The advantages of the invention and how to achieve them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete and that common knowledge in the technical field to which the present invention pertains is not limited. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. In cases where a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting components, it is interpreted to include the margin of error even if there is no separate explicit description.

Each feature of the various embodiments of the present invention can be partially or fully combined or combined with each other, and as can be fully understood by those skilled in the art, various technical interconnections and operations are possible, and each embodiment may be implemented independently of each other. It may be possible to conduct them together due to a related relationship.

For clarity of interpretation of this specification, terms used in this specification will be defined below.

As used herein, the term “electrical conductivity” refers to the degree to which a material or fluid can carry electric charge, i.e., a measure of the amount of electric current or ability to transmit electric current. Electrical conductivity is the reciprocal of electrical resistivity (unit ohm*m), and the unit of electrical conductivity is Siemens (S)/m or 1/Ωm.

Meanwhile, the term “impedance” used in this specification may refer to the degree to which the flow of current is interrupted when voltage is applied in an electric alternating current circuit. For impedance Z, if the voltage is V(V) and the current I(A), the unit is Ohm(Ω) and the symbol is Z, and if the current flowing by voltage E is I, Z=E/I(Ω). It is obtained and can be the reciprocal of electrical conductivity. Accordingly, the term “impedance” used in this specification may mean electrical conductivity.

Accordingly, the term “electrical conductivity sensor” used in this specification may refer to a sensor that measures electrical conductivity or impedance.

As used herein, the term “analysis sample” may be a solution containing an electrolyte material in a fluid. For example, it may be urine, cell lysate, whole blood, plasma, serum, saliva, ocular fluid, cerebrospinal fluid, sweat, milk, ascites fluid, synovial fluid, and peritoneal fluid. Preferably, the sample to be analyzed may be tears or a tear film, but is not limited thereto. Furthermore, “analysis sample” can be defined as a synonym for “measurement target fluid” of the electrical conductivity sensor of the present invention. Therefore, the electrical conductivity measured in the present invention may represent the concentration of the electrolyte material in the fluid to be measured.

Furthermore, the electrical conductivity sensor can be applied to electrical conductivity measurement sensors such as osmotic pressure measurement sensors including tear osmotic pressure measurement sensors, water quality sensors, dissolved oxygen sensors, and pH sensors, but is not limited thereto, and is preferably applied to tear osmotic pressure measurement sensors. It can be used.

Furthermore, the tear osmotic pressure sensor using electrical conductivity according to an embodiment of the present invention is a general term for a sensor for measuring tear osmotic pressure, and includes a substrate, a first electrode, and a second electrode, and the first electrode and It may refer to a sensor using electrochemical technology that analyzes osmotic pressure by measuring the potential difference, resistance, or impedance between electrodes in an analysis sample smeared between second electrodes.

As used herein, the term “substrate” may refer to a plate on which electrodes are formed for measuring the electrical conductivity of an analysis sample. At this time, the material of the substrate is polyethyleneterephthalate (PET), poly(methyl methacrylate), PMMA), polyimide (PI), polystyrene (PS), and polyethylene naphthalate ( It may be at least one of polyethylenenaphthalate (PEN), polycarbonate (PC), Teflon, epoxy, glass, paper, and ceramic.

However, the material of the substrate is not limited to this, and may be made of various materials on which electrodes that generate impedance according to changes in the concentration of the target material in the analysis sample can be placed.

Meanwhile, an electrode for sensing a target material in an analysis sample and a reference electrode having stable impedance, resistance, or potential difference may be disposed on the substrate.

At this time, the electrodes can be printed on one substrate and can be additionally placed on the substrate by plating techniques, sputtering techniques, evaporation techniques, photolithography, and etching techniques. However, the present invention is not limited thereto, and the electrodes may be disposed on the substrate using a variety of methods.

As used herein, the term “electrode” refers to a conductive electrode that has electrical conductivity.

At this time, the electrode disclosed in the present specification may mean an electrode pattern in which a conductive material is printed in various ways on a substrate.

For example, the electrode includes at least one organic material selected from the group consisting of carbon black, carbon graphite, graphene, fullerene, carbides, carbon nanotubes, and activated carbon on the substrate. It may be a conductive electrode formed by printing on . Additionally, the electrode may be a conductive electrode formed by printing at least one metal from Au, Ni, Cu, Zn, Fe, Al, Ti, Pt, Hg, Ag, Pb, and alloys thereof on a substrate.

As used herein, the term “first electrode” may refer to a working electrode for measuring the electrical conductivity of an analysis sample. Furthermore, it may refer to a working electrode for qualitatively and/or quantitatively sensing (detecting) a specific target substance in an analysis sample.

At this time, the first electrode may contain an ion-selective ionophore whose impedance, resistance, or potential difference changes depending on the concentration of ions, or may be an electrode made of a sensitive material that is sensitive to lactic acid, glucose, heavy metals, and pH. . Accordingly, the first electrode may refer to an area for sensing the target material in the analysis sample formed on the substrate.

For example, the first electrode may be made of a sensitive material to react with the analysis sample. Alternatively, a sensitive material may be coated on the electrode, or a sensitive material may be printed on the substrate to form the first electrode. At this time, the sensitive material may exist in some areas, such as one end of the electrode, but is not limited thereto. Furthermore, the first electrode may be electrically connected to a wiring.

Meanwhile, the sensitive material layer may be immobilized on the conductive layer disposed on the substrate by methods of adsorption, entrapment, covalent bonding, or ionic bonding.

As used herein, the term “sensitive material” may refer to a material whose impedance, resistance, or potential difference changes depending on the concentration of the target material in the analysis sample.

For example, the sensitive material may be an ion-selective material containing an ion-selective ionophore whose impedance, resistance, or potential difference changes depending on the target ion concentration. At this time, the “ion-selective material” includes an ionophore configured to selectively transport the target ion, enabling transport of the target ion to the conductive layer.

For example, ion-selective substances include Valinomycin, which has K ⁺ ion selectivity, Ca ²⁺ , and Ba ²⁺ ion selectivity. Beauvericin, Calcimycine with Mn ²⁺ , Ca ²⁺ , Mg ²⁺ ion selectivity and A23187, Cezomycin, CCCP (Carbonyl cyanide m-chlorophenyl hydrazone) with H ⁺ ion selectivity ), Enniatin with NH ₄ ⁺ ion selectivity, Gramicidin with H ⁺ , Na ⁺ , K ⁺ ion selectivity, Ionomycin with Ca ²⁺ ion selectivity, K ⁺ , Lasalocid with Na ⁺ , Ca ²⁺ , Mg ²⁺ ion selectivity, Monensin with Na ⁺ , H ⁺ ion selectivity, K ⁺ , H ⁺ , Pb ²⁺ ion selectivity At least one of the following: Nigericin, Nonactin with NH ₄ ⁺ ion selectivity, Salinomycin with K ⁺ ion selectivity, Tetronasin and Narasin May contain iononphore.

According to a feature of the present invention, the sensitive material may be a pH-sensitive material.

At this time, the term “pH sensitive material” used in this specification may mean a material that has different impedance, resistance, or potential difference depending on pH concentration. At this time, the pH-sensitive materials include polyaniline, polypyrrole, poly-N-methylpyrrole, polythiophene, and poly(ethylenedioxythiopHene). , poly-3-methylthiopHene, poly(3,4-ethylenedioxythipHene); PEDOT), poly(p-phenylenevinylene) ( It may be at least one of poly(ppHenylenevinylene); PPV) and polyfuran.

Meanwhile, among pH-sensitive materials, polyaniline may be very sensitive to H ₃ O ⁺ ions. Accordingly, when the first electrode senses the pH of the analysis sample, polyaniline may be used as a pH-sensitive material, but is not limited thereto.

According to features of the present invention, the sensitive substance may be one of a lactic acid sensitive substance, a glucose sensitive substance, and a heavy metal sensitive substance.

At this time, “lactic acid sensitive material” is a material containing lactate oxidase and may mean a material that has different impedance, resistance, or potential difference when the concentration of lactic acid changes.

Furthermore, “glucose-sensitive material” may refer to a material containing glucose oxidase and having different impedance, resistance, or potential difference in response to changes in the concentration of glucose.

Furthermore, the “heavy metal sensitive material” may be at least one of gold nanoparticles, silver nanoparticles, and iron oxide, and may exhibit different impedance, resistance, or potential difference when the concentration of the target heavy metal changes. It can mean a substance that has .

As used herein, the term “second electrode” refers to a half-cell electrode that has stable impedance, resistance, or potential difference in response to changes in electrical conductivity.

At this time, the second electrode may refer to a pattern formed by printing a conductive material, preferably a half-cell reactive material, on a substrate. Accordingly, the second electrode may refer to an area formed on the substrate.

Meanwhile, since the impedance, resistance, or potential difference of the second electrode may be predetermined, it can be used as a reference electrode that can serve as a reference when measuring the impedance, resistance, or potential difference of the analysis sample through the first electrode. there is.

Meanwhile, this second electrode may be made of a conductive material such as graphene. Alternatively, the second electrode may be formed by coating a conductive material on the electrode or printing a conductive material on the substrate. At this time, the conductive material may be disposed in some areas, such as one end of the reference electrode, but is not limited thereto.

Accordingly, in accordance with the electrical conductivity of the analysis sample of the first electrode, the second electrode may have a half-cell potential and thus may appear as a reduction electrode or an oxidation electrode different from the first electrode. Accordingly, the potential difference, resistance or impedance at the first electrode can be estimated.

Meanwhile, the “conductive material” disposed on the second electrode may be a reversible oxidation or reduction material, has low reactivity to changes in temperature or ion concentration, and may be a stable material with a constant impedance, resistance, or potential difference. These conductive materials have high reproducibility (or stability) in impedance, resistance, or potential difference, are stable in acidic or salt solutions, and can be easy to handle.

For example, conductive materials include not only conductive graphene, but also Ag/AgCl, Ag, Hg ₂ SO ₄ , Ag/Ag+, Hg/Hg ₂ SO ₄ , RE-6H, Hg/HgO, Hg/Hg ₂ Cl ₂ , Ag/Ag ₂ SO ₄ , Cu/CuSO ₄ , KCl saturated calomel half-cell (SCE) and salt bridge platinum may be materials whose impedance, resistance or potential difference are known in advance. Preferably, the conductive material may be Ag/AgCl, but is not limited thereto and may be a variety of materials.

However, without being limited thereto, the second electrode may be made of a variety of materials as long as it provides stable impedance, resistance, or potential difference as a reference electrode.

Meanwhile, the electrode of the electrical conductivity sensor of the present invention may be of a 2-electrode to 6-electrode type, but is preferably of a 2-electrode type.

As used herein, the term “non-conductive polymer” refers to an electrical insulating material, such as sulfonated tetrafluoroethylene based fluoropolymer-copolymer (Nafion), polyvinylidene fluoride (PVDF), poly(N-isopropylacrylamide) (pnipam), poly(N-isopropylmethacrylamide) )(PNIPMAm), poly(vinylpolypyrrolidone)(PVP), polytetrafluoroethylene(PTFE), polypropylene(PP), polystyrene(PS), polycarbonate(PC), poly(methyl methacrylate)(PMMA), Poly(hydroxyethyl methacrylate)(polyHEA) , poly(vinyl acetate)(PVAc), poly(methyl methacrylate)(PMA), phosphino-carboxylic acid(PCA), polybutylene(PB), poly(ethylene oxide)(PEO), polyethersulfone (PES), Nylon 66, polynorbornene , polyethylene (PE), polyvinyl chloride (PVC), Teflon, and Mylar. However, it is not limited to this and various non-conductive polymers can be layered on the electrode.

As used herein, the term “conditioning” may refer to a series of processes that maintain the electrode surface condition by immersing the electrode in a solution for a certain period of time or more during the storage period or before use. At this time, “immersion” may refer to the act of soaking in a conditioning solution. In this specification, conditioning the electrode with the conditioning solution of the present invention can prevent polarization of the electrode by reducing the time for the conditioning solution to form a layer on the electrode surface.

As used herein, the term “conditioning solution” refers to a composition used for conditioning electrodes, which includes distilled water, sodium chloride, sodium hyaluronate, carboxymethyl cellulose, sodium edetate hydrate, etc. contained in commercially available artificial tears (eye drops). It may contain at least one of potassium chloride, hydrochloric acid, sodium hydroxide, and magnesium chloride. That is, the conditioning solution according to another feature of the present invention may be artificial tears, but is not limited thereto.

Furthermore, the conditioning solution contains benzoic acid, sodium benzoate, paraoxybenzomethyl, ethyl paraoxybenzoate, propyl paraoxybenzoate, butyl paraoxybenzoate, sorbic acid, potassium sorbate, sodium sorbate, chlorobutanol, and benzalkonium chloride as preservatives. , benzethonium chloride, phenol, cresol, and chlorocresol may be further included. However, it is not limited to this.

Furthermore, the conditioning solution of the present invention is a solution that is harmless to the human body. The pH of the conditioning solution may be 4 to 9, and the osmotic pressure may be in the range of 0 to 400 mOsm.

The term “polarization” used in this specification may refer to a phenomenon in which the voltage drops due to poor movement of electrons on the electrode surface.

The term “hygroscopic paper” used in this specification may be composed of materials including paper that can hold an analysis sample in the internal space of the moisture absorbent paper, but is not limited thereto, but is a material that does not affect electrical conductivity. It can be. Additionally, the moisture absorbent paper of this specification may be configured to interview the electrode.

As used herein, the term “impedance measuring unit” may be a unit connected to one end of the first electrode and the second electrode, respectively, and configured to measure impedance, resistance, or potential difference. This impedance measuring unit may be connected to a stage different from the stage that reacts with the analysis sample to measure the impedance, resistance, or potential difference between the first electrode and the second electrode.

As used herein, the term “output unit” may be a unit configured to convert the concentration of a target substance in an analysis sample based on impedance, resistance, or potential difference. At this time, the output unit may be connected to the impedance measuring unit, and the concentration of the target substance may be estimated and provided based on the impedance of the analysis sample measured by the impedance measuring unit.

More specifically, the output unit may be a display device including a liquid crystal display device, an organic light emitting display device, etc., but is not limited thereto and may be provided in various forms as long as it provides the concentration of the target substance in the analysis sample. For example, the output unit may further include a processor configured to convert the impedance, resistance, or potential difference of the analysis sample into the concentration of the target substance.

As used herein, the term “user” may refer to an entity that measures electrical conductivity using an electrical conductivity sensor and uses the value.

The term “surface roughness” used in this specification may refer to the degree of fine irregularities of the metal surface. It can be quantified as the deviation of the surface height, and a larger deviation may indicate a greater roughness of the surface.

Hereinafter, with reference to FIGS. 1A to 1C, 2A to 2B, 3A to 3B, and 4 to 7, electrical conductivity sensors according to various embodiments of the present invention will be described in detail.

1A to 1C exemplarily illustrate an electrical conductivity sensor and its configuration according to an embodiment of the present invention.

Referring to FIG. 1A, the electrical conductivity sensor 100 includes a first substrate 110, a second substrate 120 formed on the first substrate, and a second substrate 120 formed on the first substrate 110 to detect the target substance in the analysis sample. It includes a first electrode 131 made of a sensitive material having different impedance depending on concentration, and a second electrode 132 formed on the first substrate 131 to be spaced apart from the first electrode 131 and made of a conductive material, The second substrate 132 is configured to expose the first electrode 131 and the second electrode 132. At this time, the impedance deviation within 10 seconds from the time of measuring the electrical conductivity between the first electrode 131 and the second electrode 132 is within 5%.

At this time, the impedance deviation is the impedance measurement at the starting point that has the largest deviation compared to the impedance measurement value (unit ohm) at the starting point (0 seconds) among the impedance measurement values measured during the electrical conductivity measurement period (10 seconds). It can mean dividing by a value and multiplying this ratio by 100. The symbol can be in various units, including %. Meanwhile, impedance deviation may mean electrical conductivity deviation.

Meanwhile, the second substrate 120 may be configured to have a space surrounding the first electrode 131 and the second electrode 132 so that the analysis sample can be contained.

Furthermore, the first electrode 131 and the second electrode 132 are made of carbon black, carbon graphite, graphene, fullerene, carbides, carbon nanotubes, and It may be a carbon electrode formed by printing at least one organic material among activated carbon on a substrate. Additionally, the electrode may be a conductive electrode formed by printing at least one metal from Au, Ni, Cu, Zn, Fe, Al, Ti, Pt, Hg, Ag, Pb, and alloys thereof on a substrate.

Meanwhile, according to a feature of the present invention, the first electrode 131 may be provided with a sensitive material layer (not shown) made of a sensitive material that covers a portion of the surface of the conductive layer made of a conductive material formed on the substrate. At this time, the conductive layer may be a carbon layer, but is not limited thereto.

According to a feature of the present invention, the first electrode 131 may be a working electrode whose impedance, resistance, or potential difference changes depending on the target material of the analysis sample. At this time, the sensitive material layer of the first electrode 131 may be an ion-selective membrane containing an ionophore. Meanwhile, the sensitive material layer (not shown) may have different targeted ions depending on the type of ionophore. For example, the sensitive material layer includes valinomycin, which has K ⁺ ion selectivity, Ca ²⁺ , and Ba ²⁺ ion selectivity. Beauvericin, Calcimycine with Mn ²⁺ , Ca ²⁺ , Mg ²⁺ ion selectivity and A23187, Cezomycin, CCCP (Carbonyl cyanide m-chlorophenyl hydrazone) with H ⁺ ion selectivity ), Enniatin with NH ₄ ⁺ ion selectivity, Gramicidin with H ⁺ , Na ⁺ , K ⁺ ion selectivity, Ionomycin with Ca ²⁺ ion selectivity, K ⁺ , Lasalocid with Na ⁺ , Ca ²⁺ , Mg ²⁺ ion selectivity, Monensin with Na ⁺ , H ⁺ ion selectivity, K ⁺ , H ⁺ , Pb ²⁺ ion selectivity At least one of the following: Nigericin, Nonactin with NH ₄ ⁺ ion selectivity, Salinomycin with K ⁺ ion selectivity, Tetronasin and Narasin May contain iononphore. Furthermore, the sensitive material layer may be made of a pH-sensitive material. For example, the sensitive material layer 114 is made of polyaniline, polypyrrole, poly-N-methylpyrrole, polythiophene, poly(ethylenedioxythiophene) ( poly(ethylenedioxythiopHene)), poly-3-methylthiopHene), poly(3,4-ethylenedioxythiophene) (poly(3,4-ethylenedioxythipHene); PEDOT), poly(p-phenyl) When made of at least one pH-sensitive material selected from poly(ppHenylenevinylene); PPV) and polyfuran, the first electrode may have impedance, resistance, or potential difference depending on changes in the pH of the analysis sample. . However, the sensitive material layer is not limited thereto, and may be made of a glucose-sensitive material or a heavy metal-sensitive material, depending on the purpose of the sensor.

Meanwhile, referring to FIG. 1A, the second electrode 132 is composed of a conductive layer formed on a substrate, and may be partially spaced apart from the first electrode 131 at a certain distance. This second electrode 132 may be a reference electrode that has stable impedance, resistance, or potential difference depending on the concentration of the target substance in the analysis sample.

According to the features of the present invention, the analysis sample of the present invention may be a solution containing an electrolyte material in a fluid. For example, it may be urine, cell lysate, whole blood, plasma, serum, saliva, ocular fluid, cerebrospinal fluid, sweat, milk, ascites fluid, synovial fluid, and peritoneal fluid. Preferably, the sample to be analyzed may be tears or a tear film, but is not limited thereto.

The electrical conductivity sensor 100 of the present invention may refer to a sensor that measures electrical conductivity or impedance. Furthermore, the electrical conductivity sensor 100 of the present invention can be applied to, but is not limited to, sensors that measure electrical conductivity, such as osmotic pressure measurement sensors including tear osmotic pressure measurement sensors, water quality sensors, dissolved oxygen sensors, and pH sensors. It can be used as a tear osmotic pressure measurement sensor.

Furthermore, the tear osmotic pressure sensor using electrical conductivity according to an embodiment of the present invention is a general term for a sensor for measuring tear osmotic pressure, and includes a substrate, a first electrode, and a second electrode, and the first electrode and It may refer to a sensor using electrochemical technology that analyzes osmotic pressure by measuring the potential difference, resistance, or impedance in the analysis sample smeared between the second electrodes.

1B and 1C show the amount of change in electrical conductivity (Y-axis, unit: ohm) over time (X-axis) when measuring electrical conductivity according to an embodiment of the present invention.

The curves A1 to A3 in Figure 1b mean the measured electrical conductivity (Y-axis, impedance) over time (X-axis, seconds) of the three electrical conductivity sensors without a non-conductive polymer layer on the top of the electrode, and the curves in Figure 1b. The B1 to B3 curves mean the measured electrical conductivity (Y-axis, impedance) over time (X-axis, seconds) of the electrical conductivity sensor further including a non-conductive polymer layer on top of the electrical conductivity sensor electrode.

Referring to Figure 1b, when adding a configuration that further includes a non-conductive polymer layer on the top of the electrode, the A1 to A3 curves showing the impedance (electrical conductivity) deviation in the range of 20 to 30% of Figure 1b, the electrical conductivity within 5% The electrical conductivity deviation becomes smaller with the curves B1 to B3 in FIG. 1B showing the deviation. In more detail, the deviation of the electrical conductivity of the A1 curve in FIG. 1B is reduced to the B1 curve through the addition of a non-conductive polymer layer, and further, the deviation of the A2 curve is reduced to the B2 curve and the A3 curve is reduced to the B3 curve.

Referring to FIG. 1C, the curves A1 to A5 in FIG. 1C represent the electrical conductivity measurements of five electrical conductivity sensors including unconditioned electrodes, and the curves B1 to B5 in FIG. 1B represent the electrical conductivity measurements including the conditioned electrodes. This refers to the electrical conductivity measurement value of the conductivity sensor.

Referring to FIG. 1C, even when a configuration for conditioning the electrode before measuring electrical conductivity is added, the curves A1 to A5 in FIG. 1C, which show an electrical conductivity deviation in the range of 20 to 30%, show an electrical conductivity deviation within 5%. The electrical conductivity deviation decreases with the curves B1 to B5 in FIG. 1B.

The specific details of the two configurations (including non-conductive polymer layer on the electrode and electrode conditioning) added to reduce the electrical conductivity deviation described in FIGS. 1B and 1C will be further explained with reference to FIGS. 2A to 2B and 3A to 3B below. do.

2A to 2B exemplarily show an electrical conductivity sensor including a non-conductive polymer layer 220 and its configuration according to another embodiment of the present invention.

FIG. 2A exemplarily shows the configuration of an electrical conductivity sensor 200 in which a non-conductive polymer layer 220 is formed on an electrode according to another embodiment of the present invention.

(a) of FIG. 2B exemplarily shows the electrode surfaces 131 and 132 of the electrical conductivity sensor where the deviation of the electrical conductivity measurement value is large, as shown by the solid line in FIG. 1C.

Referring to Figure 2b, a polymer layer of non-conductive polymer 220 with a thickness of 10 nm to 100 μm as shown in Figure 2b (b) is formed on the electrode surfaces 131 and 132 having high surface roughness as shown in Figure 2b (a). By forming (220), an electrode surface with small and constant surface roughness can be obtained, which reduces the deviation from 20 to 30% within 10 seconds from the time of impedance measurement (solid line in Figure 1c) to within 5%. (dotted line in FIG. 1C) can be reduced (see FIG. 1C).

At this time, the non-conductive polymer layer 220 may be formed on the uppermost surface of the electrode. Preferably, the non-conductive polymer layer may be formed facing the first electrode 131 and the second electrode 132, but is limited to this. It doesn't work.

Meanwhile, according to the characteristics of the present invention, the thickness of the non-conductive polymer layer may be 10 nm to 100 μm thick.

Furthermore, according to the features of the present invention, the non-conductive polymer is sulfonated tetrafluoroethylene based fluoropolymer-copolymer (Nafion), polyvinylidene fluoride (PVDF), poly(N-isopropylacrylamide) (pnipam), poly(N-isopropylmethacrylamide) (PNIPMAm) , poly(vinylpolypyrrolidone)(PVP), polytetrafluoroethylene(PTFE), polypropylene(PP), polystyrene(PS), polycarbonate(PC), poly(methyl methacrylate)(PMMA), Poly(hydroxyethyl methacrylate)(polyHEA), poly(vinyl acetate)(PVAc), poly(methyl methacrylate)(PMA), phosphino-carboxylic acid(PCA), polybutylene(PB), poly(ethylene oxide)(PEO), polyethersulfone (PES), Nylon 66, polynorbornene, polyethylene(PE) ), polyvinyl chloride (PVC), Teflon, and Mylar. However, it is not limited to this and various non-conductive polymers can be layered on the electrode.

Meanwhile, according to the features of the present invention, the surface roughness of the electrode on which the non-conductive polymer layer is formed may be 10 nm to 30 nm.

Accordingly, the electrical conductivity sensor 200 of the present invention can be used as a tear osmotic pressure sensor for measuring the osmotic pressure of tears using electrical conductivity.

3A to 3B exemplarily illustrate an electrical conductivity sensor 300 including a conditioning solution container and its configuration according to another embodiment of the present invention.

FIG. 3A exemplarily shows the configuration of an electrical conductivity sensor 300 provided while being supported in a conditioning solution container 320 according to another embodiment of the present invention. At this time, the part supported in the conditioning solution 310 may refer to the electrode part.

(a) of FIG. 3B exemplarily illustrates the electrode surfaces 131 and 132 of the electrical conductivity sensor where the deviation of the electrical conductivity measurement value is large, as shown by the solid line in FIG. 1B. When the conditioning solution forms a layer 310' as shown in Figure 3b (b) on the electrode surfaces 131 and 132 with high surface roughness as shown in Figure 3b (a), an electrode surface with small surface roughness and constant consistency can be obtained. As a result, the deviation that reached 20-30% within 10 seconds from the time of impedance measurement (solid line in Figure 1b) can be reduced to a deviation within 5% (dotted line in Figure 1b) (see Figure 1b). Furthermore, this can reduce the polarization phenomenon.

Accordingly, the electrical conductivity sensor 300 shown as an example in FIG. 3A may be provided to the user by being carried in a conditioning solution container 320 containing the conditioning solution 310.

Furthermore, the electrical conductivity sensor 300 provided to the user can be used as a tear osmotic pressure sensor for measuring the osmotic pressure of tears using electrical conductivity.

4 to 7 exemplarily illustrate electrical conductivity sensors to which components according to various embodiments of the present invention are added.

FIG. 4 exemplarily shows an electrical conductivity sensor 400 that further includes a temperature sensor 410 for measuring the temperature of an analysis sample on the exposed portion of the first substrate.

According to a feature of the present invention, electrical conductivity may increase as the temperature increases, so when measuring electrical conductivity, the electrical conductivity value according to temperature can be corrected by a temperature sensor.

FIG. 5 exemplarily shows an electrical conductivity sensor 500 in which the exposed upper portions of the first electrode, second electrode, and first substrate are covered with moisture absorbent paper (510, 510').

According to the features of the present invention, the moisture absorbent paper (510, 510') may be made of a material such as cellulose paper, fiber, or sponge that can hold the analysis sample in the internal space of the moisture absorbent paper, but is not limited thereto, but It may be a material that is non-reactive to the analysis sample and does not affect electrical conductivity.

Furthermore, referring to Figure 5, the moisture absorbent paper of the present specification may be configured to face the electrode. As such, the electrical conductivity sensor of the present specification including moisture-absorbing paper can support an analysis sample through the moisture-absorbing paper, and furthermore, due to the configuration including moisture-absorbing paper, a space surrounding the first electrode and the second electrode may not be formed.

According to various embodiments of the present invention, when measuring tear osmotic pressure using the electrical conductivity sensor of the present invention, even a small amount of sample that is difficult to collect, such as tears, is not lost to the outside of the sensor through the moisture absorbent paper, and the sample is not in contact with the electrode. You can.

The electrical conductivity sensor 600 shown in FIG. 6 is configured so that the second substrate 120 covers the first and second electrodes, and a space is formed inside so that the analysis sample can come into contact with the electrodes. At this time, a microfluidic channel 610 is formed on one side of the internal space. Other microfluidic channels 620 and 630 may be formed on different sides of the internal space for capillary action.

According to various embodiments of the present invention, when measuring tear osmotic pressure using the electrical conductivity sensor of the present invention, the tear sample, which is an analysis sample, is introduced into the microfluidic channel 610 through capillary action, and the air in the internal space is transferred to the other side. It flows out into the microfluidic channels (620, 630). Through this, even a small amount of sample, such as a tear sample, can flow into the internal space where the electrode is located without external leakage.

The electrical conductivity sensor 700 shown in FIG. 7 also has microfluidic channels 710, 720, and 730 like the electrical conductivity sensor 600 shown in FIG. 6. At this time, the second substrate 120 is configured to cover the first and second electrodes, so that the analysis sample can flow into the internal space through the microfluidic channel 710 formed on one side of the internal space.

Meanwhile, the second substrate of the electrical conductivity sensor shown in FIG. 7 is configured to cover only the top of the first electrode and the second electrode. The open upper surface formed through this can reduce the probability of losing the analysis sample when collecting or smearing the analysis sample.

Figure 8 exemplarily illustrates an electrical conductivity measurement procedure according to various embodiments of the present invention.

Referring to FIG. 8, to measure electrical conductivity, an analysis sample is first applied to the electrode area of the electrical conductivity sensor (S710). Next, the impedance of the first electrode and the second electrode is measured (S720), and the electrical conductivity of the analysis sample is determined based on the impedance (S730).

According to various embodiments of the present invention, the sample to be analyzed may be a small amount of sample, such as tears or tear film.

According to various embodiments of the present invention, in the electrical conductivity measurement procedure of the present invention, tears may be applied to the electrode area as an analysis sample to measure tear osmotic pressure. Furthermore, non-conductive polymer coating or electrode conditioning of the electrical conductivity sensor electrode used in this measurement procedure has the effect of obtaining electrical conductivity measurement values with reduced measurement deviation even in small amounts of samples such as tears.

9A to 9B exemplarily illustrate procedures for manufacturing an electrical conductivity sensor according to various embodiments of the present invention.

FIG. 9A exemplarily illustrates a manufacturing method procedure of an electrical conductivity sensor including an electrode on which a non-conductive polymer layer is disposed according to various embodiments of the present invention.

Referring to FIG. 9A, the method of manufacturing an electrical conductivity sensor first places a first electrode and a second electrode on a first substrate to be spaced apart from each other (S910), and the second substrate disposed on the first substrate is used to store the analysis sample. After constructing a space surrounding the first and second electrodes so that they can be in contact with the first and second electrodes (S920), the impedance (ohm) deviation within 10 seconds from the time of measuring the electrical conductivity is within 5%, It consists of disposing a non-conductive polymer layer facing the first electrode and the second electrode on top of the first electrode and the second electrode (S930).

At this time, the thickness of the non-conductive polymer layer may be 10 nm to 100 μm thick, and further, the non-conductive polymer may be sulfonated tetrafluoroethylene based fluoropolymer-copolymer (Nafion), polyvinylidene fluoride (PVDF), poly(N-isopropylacrylamide) ( pnipam), poly(N-isopropylmethacrylamide)(PNIPMAm), poly(vinylpolypyrrolidone)(PVP), polytetrafluoroethylene(PTFE), polypropylene(PP), polystyrene(PS), polycarbonate(PC), poly(methyl methacrylate)(PMMA), Poly(hydroxyethyl methacrylate)(polyHEA), poly(vinyl acetate)(PVAc), poly(methyl methacrylate)(PMA), phosphino-carboxylic acid (PCA), polybutylene(PB), poly(ethylene oxide)(PEO), polyethersulfone It may be at least one of (PES), Nylon 66, polynorbornene, polyethylene (PE), polyvinyl chloride (PVC), Teflon, and Mylar, but is not limited thereto.

Furthermore, methods for disposing the non-conductive polymer layer include electrochemical deposition, sputtering, printing, chemical vapor deposition, initiated chemical vapor deposition using an initiator, and spraying. , at least one method of dip coating and sol-gel coating may be used, but is not limited thereto.

FIG. 9B exemplarily illustrates a manufacturing method procedure of an electrical conductivity sensor including a conditioning solution container according to various embodiments of the present invention.

Referring to FIG. 9B, the method of manufacturing an electrical conductivity sensor first arranges a first electrode and a second electrode on a first substrate to be spaced apart from each other (S915), and arranges a second substrate on the first substrate, with the second electrode disposed on the first substrate. After forming a space surrounding the first and second electrodes so that the substrate can contain the analysis sample in contact with the first and second electrodes (S925), the impedance (ohm) within 10 seconds from the time of measuring the electrical conductivity It consists of immersing the first electrode and the second electrode in a conditioning solution container containing a conditioning solution so that the deviation is within 5% (S935).

At this time, the conditioning solution is a composition with a pH of 4 to 9 and an osmotic pressure of 0 to 400 mOsm, and is composed of distilled water, sodium chloride, sodium hyaluronate, carboxymethyl cellulose, sodium edetate hydrate, and potassium chloride contained in commercially available artificial tears (eye drops). , may include at least one of hydrochloric acid, sodium hydroxide, and magnesium chloride, but is not limited thereto.

Furthermore, the conditioning solution contains benzoic acid, sodium benzoate, paraoxybenzomethyl, ethyl paraoxybenzoate, propyl paraoxybenzoate, butyl paraoxybenzoate, sorbic acid, potassium sorbate, sodium sorbate, chlorobutanol, and benzalkonium chloride as preservatives. , benzethonium chloride, phenol, cresol, and chlorocresol may be further included, but are not limited thereto.

<Evaluation of electrical conductivity sensors according to various embodiments of the present invention>

10A to 10B show performance evaluation results of conditioned electrical conductivity sensors according to various embodiments of the present invention.

Figure 10a shows the standard curve of the electrical conductivity sensor without conditioning, and the linearity of the standard curve was found to be low (coefficient of determination (R ² ) value = 0.87).

On the other hand, Figure 10b shows a standard curve when the electrical conductivity sensor carried in a conditioning solution container containing a conditioning solution was calibrated with a physiological saline standard solution, and shows the electrical conductivity sensor carried in a conditioning solution container containing a conditioning solution. The linearity of the standard curve when corrected with a physiological saline standard solution showed a value suitable as a standard curve (coefficient of determination (R ² ) value = 0.98).

That is, this may mean that the conditioned electrical conductivity sensor according to various embodiments of the present invention discloses a highly reliable electrical conductivity value.

<Surface roughness of electrical conductivity sensors according to various embodiments of the present invention>

11A to 11B show enlarged images of the electrode surface on which the non-conductive polymer layer is disposed according to various embodiments of the present invention.

Figure 11a is a photograph taken with a scanning electron microscope (SEM) of an electrode coated with PVDF, a commercially available non-conductive polymer. The resolution of A in Figure 11a is 1 mm, B is 500 μm, C is 50 μm, D is 2 μm, E is 5 μm, and F is 1 μm.

Figure 11b is a photograph taken with a scanning electron microscope (SEM) after forming a layer of Nafion (sulfonated tetrafluoroethylene based fluoropolymer-copolymer), a non-conductive polymer, on the electrode surface facing the electrode. The resolution of A in Figure 11b is 1 mm, B is 500 μm, C is 50 μm, D is 10 μm, E is 5 μm, and F is 2 μm.

Referring to Figure 11b, the electrode surface coated with the Nafion layer, a non-conductive polymer of the present invention, has a uniform shape even at a resolution of 2 μm (see Figure 11b).

However, looking at the 1 μm resolution photo of the PVDF-coated electrode in FIG. 11a, it can be seen that the surface roughness is greater than that of the electrode on which the Nafion layer of the present invention is disposed (see FIG. 11a).

Figures 12a and 12b show the results of measuring surface roughness using an atomic force microscope for an electrode surface on which a non-conductive polymer layer is not disposed or on an electrode surface on which a non-conductive polymer layer is disposed according to various embodiments of the present invention.

Figure 12a (a) shows the results of measuring the surface roughness using atomic force microscopy (AFM) on the electrode surface on which the non-conductive polymer layer is not disposed according to various embodiments of the present invention, and in Figure 12a (b) shows the distribution of measured surface roughness as a histogram.

Figure 12b (a) shows surface roughness measured using atomic force microscopy (AFM) on the electrode surface coated with Nafion (sulfonated tetrafluoroethylene based fluoropolymer-copolymer), a non-conductive polymer according to various embodiments of the present invention. One result is shown, and Figure 12b (b) shows the distribution of the measured surface roughness as a histogram.

More specifically, the bar graph on the left of (a) of FIGS. 12A to 12B shows a color indicator according to surface roughness, and in the above-described bar graph on the left of (a) of FIGS. 12A to 12B, The surface roughness is in the range of about -125 nm to 200 nm, and the lower the surface height, the smaller the negative number, and the color is dark black. The higher the surface height, the higher the surface roughness is the positive number, and the color is bright white. Meanwhile, in the above-described bar graph, surface roughness '0' means the average height of the coated electrode surface.

Furthermore, the right drawing of Figures 12a and 12b (a) shows the surface roughness of an electrode measuring 100 μm ² in color using an atomic force microscope.

Furthermore, Figures 12a to 12b (b) show the distribution of surface roughness as a histogram, where 'pxl' on the Y-axis represents the number (count) of specific surface roughness expressed in pixels (pixels, points), and the Indicates illuminance.

Referring to Figure 12b (b), the surface roughness of the electrode surface coated with Nafion, a non-conductive polymer of the present invention, shows the maximum distribution at an average surface roughness of 0 nm, and most of the surface roughness is limited to the range of -4 to 12 nm. It turned out to be possible.

However, referring to FIG. 12A, the surface roughness of the uncoated electrode of the present invention peaks at -30 nm, and the surface roughness ranges from about -130 to 100 nm. Through this, it can be seen that the surface roughness is greater than that of the electrode coated with non-conductive polymer in Figure 12a. Furthermore, it can be seen that the thickness of the coated non-conductive polymer layer is about 30 nm. However, the thickness of the non-conductive polymer layer is not limited to this.

Therefore, the electrical conductivity sensor coated with a non-conductive polymer according to various embodiments of the present invention may mean that an electrode with low surface roughness is introduced. Furthermore, the impedance deviation of the electrode is reduced due to the electrode having a small surface roughness, which means that a highly reliable electrical conductivity sensor can be provided.

Accordingly, the electrical conductivity sensor according to various embodiments of the present invention is connected to one end of the first electrode and the second electrode, respectively, and is connected to an impedance measuring unit configured to measure impedance, and an impedance measuring unit to measure electricity based on the impedance. It can be provided as an electrical conductivity measuring device that outputs conductivity.

Although embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and may be modified and implemented in various ways without departing from the technical spirit of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but rather to explain it, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

100, 200, 300, 400, 500, 600, 700: Biosensor
110: first substrate
120: second substrate
131, 132: first electrode, second electrode
220: Non-conductive polymer layer
310: Conditioning solution
310': conditioning solution layer
320: Conditioning solution container
410: Temperature sensor
510, 510': moisture absorbent paper
610, 620, 630: Microfluidic channel
710, 720, 730: Microfluidic channel

Claims (21)

first substrate;
a second substrate on the first substrate;
On the first substrate, a first electrode made of a sensitive material having different impedance depending on the concentration of the target material in the analysis sample; and
It includes a second electrode on the first substrate, spaced apart from the first electrode and made of a conductive material,
The second substrate is configured to expose the first electrode and the second electrode,
The impedance deviation within 10 seconds from the time of measuring the electrical conductivity between the first electrode and the second electrode is within 5%,
Each of the first electrode and the second electrode,
It further includes a non-conductive polymer layer on the top surface facing the first and second electrodes,
The surface roughness of the surface in contact with the analysis sample of the non-conductive polymer layer is,
Electrical conductivity sensor, 10 nm to 30 nm. According to claim 1,
The second substrate is configured to have a space surrounding the first electrode and the second electrode so that an analysis sample can be contained. delete According to claim 1,
The thickness of the non-conductive polymer layer is 10 nm to 100 μm thick, an electrical conductivity sensor. According to claim 1,
The non-conductive polymer includes sulfonated tetrafluoroethylene based fluoropolymer-copolymer (Nafion), polyvinylidene fluoride (PVDF), poly(N-isopropylacrylamide) (pnipam), poly(N-isopropylmethacrylamide) (PNIPMAm), poly(vinylpolypyrrolidone) (PVP), polytetrafluoroethylene (PTFE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(hydroxyethyl methacrylate)(polyHEA), poly(vinyl acetate)(PVAc), poly(methyl methacrylate (PMA), phosphino-carboxylic acid (PCA), polybutylene (PB), poly(ethylene oxide) (PEO), polyethersulfone (PES), Nylon 66, polynorbornene, polyethylene (PE), polyvinyl chloride (PVC), Teflon , and Mylar, an electrical conductivity sensor. delete According to claim 1,
further comprising a conditioning solution container,
An electrical conductivity sensor, wherein the conditioning solution container is configured to contain the first electrode and the second electrode in the conditioning solution. According to clause 7,
The conditioning solution is a composition having a pH of 4 to 9 and an osmotic pressure of 0 to 400 mOsm, and contains distilled water, sodium chloride, sodium hyaluronate, carboxymethyl cellulose, sodium edetate hydrate, potassium chloride, hydrochloric acid, sodium hydroxide and magnesium chloride. An electrical conductivity sensor comprising at least one and a preservative. According to claim 1,
Electrical conductivity sensor further comprising a temperature sensor for measuring the temperature of the analysis sample on the exposed portion of the first substrate. According to claim 1,
The electrical conductivity sensor further includes moisture absorbent paper covering the exposed top of the first electrode, the second electrode, and the first substrate. According to clause 2,
The second substrate is configured to cover the upper part of the space,
An electrical conductivity sensor further comprising two or more microfluidic channels on one side of the space so that the analysis sample flows into the space by capillary action. According to clause 2,
The second substrate is configured to cover the upper part of the space,
Configured to cover only the top of the first electrode and the second electrode,
One side of the space is open so that the analysis sample flows into the space by capillary action,
An electrical conductivity sensor further comprising another microfluidic channel on another side of the space. According to claim 1,
The electrical conductivity sensor further includes that the first electrode or the second electrode is a carbon electrode. Placing the analysis sample on the electrical conductivity sensor according to any one of claims 1, 2, 4, 5, 7 to 13,
measuring the impedance of the first electrode and the second electrode, and
A method of measuring electrical conductivity, comprising determining the electrical conductivity of the analysis sample based on the impedance. Arranging a first electrode and a second electrode on a first substrate, wherein the second electrode is spaced apart from the first electrode,
Placing a second substrate on the first substrate, wherein the second substrate forms a space surrounding the first electrode and the second electrode so that the analysis sample can be contained in contact with the first electrode and the second electrode, and
Placing a non-conductive polymer layer facing the first and second electrodes on top of the first and second electrodes so that the impedance (ohm) deviation within 10 seconds from the time of measuring the electrical conductivity is within 5%. Including,
The surface roughness of the surface in contact with the analysis sample of the non-conductive polymer layer is,
A method of manufacturing an electrical conductivity sensor, which is 10 nm to 30 nm. According to claim 15,
A method of manufacturing an electrical conductivity sensor, wherein the thickness of the non-conductive polymer layer is 10 nm to 100 μm thick. According to claim 15,
The non-conductive polymer includes sulfonated tetrafluoroethylene based fluoropolymer-copolymer (Nafion), polyvinylidene fluoride (PVDF), poly(N-isopropylacrylamide) (pnipam), poly(N-isopropylmethacrylamide) (PNIPMAm), poly(vinylpolypyrrolidone) (PVP), polytetrafluoroethylene (PTFE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(hydroxyethyl methacrylate)(polyHEA), poly(vinyl acetate)(PVAc), poly(methyl methacrylate (PMA), phosphino-carboxylic acid (PCA), polybutylene (PB), poly(ethylene oxide) (PEO), polyethersulfone (PES), Nylon 66, polynorbornene, polyethylene (PE), polyvinyl chloride (PVC), Teflon And a method of manufacturing an electrical conductivity sensor, which is at least one of Mylar. According to claim 15,
Methods for disposing the non-conductive polymer layer include electrochemical deposition, sputtering, printing, chemical vapor deposition, initiated chemical vapor deposition using an initiator, spraying, A method of manufacturing an electrical conductivity sensor, which uses at least one method of dip coating and sol-gel coating. Arranging a first electrode and a second electrode on a first substrate, wherein the second electrode is spaced apart from the first electrode,
Placing a second substrate on the first substrate, wherein the second substrate forms a space surrounding the first electrode and the second electrode so that the analysis sample can be contained in contact with the first electrode and the second electrode,
Ensure that the impedance (ohm) deviation within 10 seconds from the time of measuring electrical conductivity is within 5%,
Disposing a non-conductive polymer layer facing the first and second electrodes on top of the first and second electrodes, and
A step of immersing the first electrode and the second electrode in a conditioning solution container containing a conditioning solution,
The surface roughness of the surface in contact with the analysis sample of the non-conductive polymer layer is,
Method for manufacturing an electrical conductivity sensor, 10 nm to 30 nm. According to clause 19,
The conditioning solution is a composition having a pH of 4 to 9 and an osmotic pressure of 0 to 400 mOsm, and contains distilled water, sodium chloride, sodium hyaluronate, carboxymethyl cellulose, sodium edetate hydrate, potassium chloride, hydrochloric acid, sodium hydroxide and magnesium chloride. A method of manufacturing an electrical conductivity sensor, comprising at least one and a preservative. The electrical conductivity sensor according to any one of claims 1, 2, 4, 5, 7 to 13;
An impedance measuring unit connected to one end of the first electrode and the second electrode of the electrical conductivity sensor, respectively, and configured to measure impedance, and
An electrical conductivity measuring device comprising an output unit connected to the impedance measuring unit and configured to output electrical conductivity based on the impedance.

Images