KR20220143482A - Patch-type device for measuring glucose in blood - Google Patents

Abstract

The present invention provides a blood glucose measurement device capable of quantitatively measuring the amount of blood glucose in a body quickly and conveniently without requiring external power. The patch-type blood glucose measurement device comprises: a substrate having a dye deposited on a surface thereof; a biosensor that measures blood glucose; and a circuit electrically connecting the biosensor and the substrate.

Description

PATCH-TYPE DEVICE FOR MEASURING GLUCOSE IN BLOOD

The present disclosure relates to a patch type blood glucose measurement device capable of quantitatively measuring the amount of blood glucose in the body quickly and conveniently without requiring external power.

Most of the existing sensors used to measure the concentration of substances in body fluids directly collect blood, put it in a kit, and analyze the concentration of substances in the blood using an external measuring device. Since this method directly collects and analyzes blood, the exact concentration of the substance to be measured can be confirmed. In addition, for measurement, a measuring device and a power source to drive these devices are required, and there is an inconvenience of having to change a new kit every time it is measured.

There is also a method of analysis using body fluids such as tears, saliva, and sweat without using blood. This is a method of calculating the correlation between the concentration of the target substance in blood and the concentration of the target substance in the body fluid by linearizing it. However, since the concentration of substances in tears, saliva, and sweat is very small, accurate measurement is difficult, the equipment is expensive, and body fluids such as tears, saliva, and sweat are exposed to the external environment and can be easily contaminated. Accurate values can be difficult to obtain.

To solve this problem, an analysis method using a microneedle exists, but most methods use a method of obtaining a quantitative value by connecting a target material obtained through the microneedle to a complex semiconductor array structure. This method is expensive because it requires a complex semiconductor array structure, and is also inconvenient because the semiconductor array structure requires an external power source.

Since all existing methods for measuring the concentration of a substance in blood require an external power source and take a long time, there is a need for a method for measuring the concentration of a target substance in the blood simply, quickly and accurately without an external power supply.

The above-mentioned background art is possessed or acquired by the inventor in the process of deriving the disclosure of the present application, and it cannot necessarily be said to be a known technology disclosed to the general public prior to the present application.

Korean Patent Publication No. 10-2021-0026989 (2021.03.10)

An object of the present disclosure is to provide a patch-type blood glucose measurement device capable of conveniently measuring the concentration of blood glucose within a short period of time. The patch is inexpensive, disposable, and can provide a blood glucose concentration easily and quickly with the naked eye through a spontaneous electrochemical reaction.

As one aspect for achieving the above object, the present disclosure provides

a substrate having a dye deposited thereon;

a biosensor attached to a surface opposite to the surface of the substrate on which the dye is deposited and measuring blood glucose; and

A patch-type blood glucose measurement device comprising a circuit electrically connecting the biosensor and the substrate,

The biosensor includes a plurality of microneedle structures, some of the plurality of microneedle structures contain glucose oxidase and act as a cathode, and the other part of the plurality of microneedle structures is an inert electrolyte Acts as a salt bridge, including

The substrate and the dye act as an anode, the dye exhibits a color change due to the redox reaction between the anode and the cathode, and the substrate uses the degree of color change of the dye displayed on the surface of the substrate to be the biosensor Provided is a patch-type blood glucose measurement apparatus that quantitatively displays the amount of blood glucose measured from

According to one embodiment, the dye is Prussian blue.

According to one aspect, the dye is deposited to form a plurality of rectangular features arranged in parallel and spaced apart from each other on the surface of the substrate.

In one aspect, the color change of the dye is observable with the naked eye through the features.

According to one aspect, the substrate comprises a flexible material.

The blood glucose measurement device according to the present disclosure can measure the concentration of blood glucose conveniently within a short time. In addition, the blood glucose measurement device according to the present disclosure is inexpensive and disposable, and provides the blood glucose concentration easily and quickly with the naked eye without requiring external power.

1 shows the principle of an apparatus according to the present disclosure;
2 illustrates a method of using an apparatus according to the present disclosure.
3 schematically shows that the device according to the present disclosure operates as an electrochemical cell by itself, without the need for an external power source.
4A illustrates a structure of a patch-type blood glucose measurement apparatus according to the present disclosure.
4B shows the arrangement of the microneedle structure of the patch-type blood glucose measurement device according to an embodiment of the present disclosure.
4C shows the arrangement of the microneedle structure of the patch-type blood glucose measurement device according to another embodiment of the present disclosure.
5 schematically shows a simulation structure of the blood glucose measurement apparatus according to the embodiment.
6 shows an image of a simulation structure of the blood glucose measurement apparatus according to the embodiment.
7 shows the results of the simulation structure of the blood glucose measurement apparatus according to the embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, since various changes may be made to the embodiments, the scope of the patent application is not limited or limited by these embodiments. It should be understood that all modifications, equivalents and substitutes for the embodiments are included in the scope of the rights.

Terms used in the examples are used for the purpose of description only, and should not be construed as limiting. 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 in the specification exists, but one or more other features It is to be understood that this 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 the embodiment 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 application. does not

In addition, in the description with reference to the accompanying drawings, the same components are assigned the same reference numerals regardless of the reference numerals, and the overlapping description thereof will be omitted. In the description of the embodiment, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but between each component another component It will be understood that may also be "connected", "coupled" or "connected".

Components included in one embodiment and components having a common function will be described using the same names in other embodiments. Unless otherwise stated, descriptions described in one embodiment may be applied to other embodiments as well, and detailed descriptions within the overlapping range will be omitted.

One aspect of the present invention is

a substrate having a dye deposited thereon;

a biosensor attached to a surface opposite to the surface of the substrate on which the dye is deposited and measuring blood glucose; and

A patch-type blood glucose measurement device comprising a circuit electrically connecting the biosensor and the substrate,

The biosensor includes a plurality of microneedle structures, some of the plurality of microneedle structures contain glucose oxidase and act as a cathode, and the other part of the plurality of microneedle structures is an inert electrolyte Acts as a salt bridge, including

The substrate and the dye act as an anode, the dye exhibits a color change due to the redox reaction between the anode and the cathode, and the substrate uses the degree of color change of the dye displayed on the surface of the substrate to be the biosensor Provided is a patch-type blood glucose measurement apparatus that quantitatively displays the amount of blood glucose measured from

An operating principle of the patch-type blood glucose measurement apparatus according to the present disclosure is described in FIG. 1 . Since the microneedle of the patch-type device can penetrate to the dermal layer of the skin as illustrated in FIG. 2 , it is possible to extract a small amount of body fluid from the subject. The patch is conveniently attached to the skin surface of the subject and is operable. At this time, the extracted bodily fluid is interstitial fluid existing in the dermis, and since the glucose concentration in the interstitial fluid is very similar to that of blood, the blood glucose concentration can be confirmed by checking the glucose concentration in the interstitial fluid existing in the dermis.

Glucose in the extracted body fluid undergoes an electrochemical reaction with a selective substance contained in the microneedle, that is, glucose oxidase. In other words, the microneedle itself containing glucose oxidase and glucose acts as a cathode. On the other hand, the substrate of the patch type blood glucose measurement device acts as an anode. Therefore, as illustrated in FIG. 3 , since the entire device operates as one electrochemical cell and the redox reaction occurs spontaneously, an external power source is not required.

The presence and amount of blood glucose is observed through color change of a dye deposited on a substrate serving as an anode of a patch type blood glucose measurement device. That is, the dye acts as an indicator of the redox reaction. The dye, preferably Prussian blue dye, initially exhibits blue color, but loses color and becomes transparent as it is reduced together with the positive electrode active material at the positive electrode. That is, Prussian blue changes color depending on the presence or absence of glucose. This color change of Prussian blue to a transparent color is actually seen as a color change from the anode surface to white.

In addition, when the amount of glucose is large, the amount of the dye causing the color change to white is large, and when the amount of glucose is small, the amount of the dye causing the color change to white is reduced. Therefore, it is possible to quantitatively identify glucose according to the degree of color change.

Specifically, the structure of the patch-type blood glucose measurement apparatus 100 according to the present disclosure is illustrated in FIG. 4A . A biosensor 20 including a plurality of microneedle structures is attached to the surface of the substrate 10 . A dye 11 is deposited on the opposite surface of the substrate. A circuit 30 electrically connecting the biosensor and the substrate is included.

Some of the plurality of microneedle structures of the biosensor act as a cathode. The chemical reactions taking place at these cathodes are:

[reaction formula]

The remaining part of the plurality of microneedle structures of the biosensor acts as a salt bridge. When the anode and the cathode are separated from each other, a salt bridge containing an inert electrolyte is used to balance the charge between the anode and the cathode. In the patch-type blood glucose measurement apparatus according to the present disclosure, the structures of the positive electrode and the negative electrode are separated from each other in order to prevent the dye from directly touching or penetrating the skin or dermal layer of the subject. Accordingly, the device includes a salt bridge without using a separation membrane. The inert electrolyte that can be used for the salt bridge includes all inert electrolyte salts that do not participate in the electrode reaction and can be used for the salt bridge, for example, potassium chloride and sodium chloride.

The microneedle structure as a salt bridge and the microneedle structure as the negative electrode are mixed and arranged. According to one embodiment, as shown in Figure 4b, the structure 22 of the salt bridge and the structure 21 of the cathode may be alternately arranged one by one. According to another embodiment, as shown in FIG. 4c , the structure 22 of the salt bridge and the structure 21 of the cathode may be alternately arranged one by one.

The negative electrode structure may further include a mediator material and a support material in addition to glucose oxidase. A mediator is a substance that transfers electrons formed by the oxidation reaction of glucose and glucose oxidase. Any material known in the art to have electron transport properties can be used as the mediator without limitation, and examples of the mediator include tetrathiafulvalene (TTF), ferrocene, quinone, tetrathiafulvalene, and methylene. green or a combination thereof. Preferably, the mediator is Tetrathiafulvalene (TTF). The supporting material serves to support the glucose oxidase and the mediator so that the glucose oxidase and the mediator are well distributed in the negative electrode structure, so that the electrons generated by the oxidation reaction can be quickly transferred. The support material may be a material having a mesh structure that forms a three-dimensional network. The support material may be used without limitation as long as it serves to support the glucose oxidase and the mediator so that they can be well distributed, and examples of the support material include Nafion, gelatin, chitosan, and combinations thereof. Preferably, the support material is gelatin.

Alternatively, the glucose oxidase and the mediator may be one. That is, one substance can play a role of glucose oxidase, ie, selectively causing a redox reaction with glucose while having electron-mediated properties. In this case, two separate substances, a mediator and glucose oxidase, may not be used. Examples of such materials include nanozymes, and glucose dehydrogenase.

The substrate acts as a cathode electrode, and the dye deposited on the substrate acts as a cathode active material. A dye 11, preferably Prussian Blue, is deposited on the surface of the substrate. Prussian blue is a deep blue dye produced by oxidation of a ferrous ferrocyanide salt, and is a material having a structural formula of Fe ^III ₄ [Fe ^II (CN) ₆ ] ₃ ·xH ₂ O. represents dark blue. Prussian blue loses color as it is reduced and becomes transparent. Therefore, it is used as an indicator of the redox reaction between the anode and the cathode.

As shown in FIG. 4A , the substrate may have a plurality of rectangular-shaped features 11a , 11b , 11c , 11d arranged in parallel and spaced apart from each other on a surface thereof. The dye 11 may be deposited to form a plurality of rectangular-shaped features 11a, 11b, 11c, and 11d spaced apart from each other and arranged in parallel on the surface of the substrate. Accordingly, the amount of glucose can be visually observed through the color change of the deposited dye while forming these features on the surface of the substrate. Specifically, the degree of color change may be known through the number of features observed for color change (ie, color change from blue to white). In other words, the higher the concentration of glucose in the body fluid, the greater the number of features turned white. On the other hand, as the concentration of glucose in the body fluid is lower, the number of features that have turned white decreases and the number of features that show blue increases.

The deposition of the dye may be performed through various deposition methods. For example, the dye may be deposited on the substrate via electro-deposition.

The substrate may include a material usable as an electrode. In one aspect, the substrate is indium tin oxide (ITO) glass. In another aspect, the substrate may include a flexible material. For example, the substrate may include a polyethylene terephthalate (PET) film, polydimethylsiloxane (PDMS), or a combination thereof.

The circuit 30 electrically connects the biosensor and the substrate. Specifically, the circuit electrically connects the microneedle structure of the negative electrode of the biosensor and the substrate. Electrons generated while oxidizing glucose to gluconolactone at the cathode of the device are transferred to the anode substrate through a circuit, and the dye deposited on the anode receives these electrons and is reduced. Such a circuit may connect the negative electrode and the positive electrode through an electric wire located inside the substrate.

On the other hand, the salt bridge of the microneedle structure is connected to the substrate, that is, the positive electrode, and the ionic material of the inert electrolyte salt in the salt bridge is transferred to the positive electrode. Due to the redox reaction at the anode, the charge balance of the anode is required, so the ions inside the salt bridge move to the anode. On the other hand, since the microneedle structure is located in the dermal layer in the skin, the structure of the negative electrode and the structure of the salt bridge are connected to the body fluid in the dermal layer. Therefore, it may not be necessary to separately connect the salt bridge and the negative electrode.

Since the blood glucose measurement apparatus according to the present disclosure uses a spontaneous electrochemical reaction of glucose and observes a color change through a redox reaction of a dye, it is possible to measure the concentration of glucose simply and efficiently without an external power source.

In addition, it is possible to directly measure blood glucose by attaching a patch without blood collection, and to check the amount of glucose with the naked eye. Specifically, the device controls the concentration of glucose within about 5 minutes, preferably within about 3 minutes, preferably within about 2 minutes, preferably within about 1 minute, preferably within about 30 seconds, preferably within about It is possible to measure within 15 seconds. This rapid confirmation of the concentration of glucose is very useful in preventing shock caused by hypoglycemia.

In addition, since the blood glucose measurement apparatus according to the present disclosure does not use a complex semiconductor structure, it has the advantage of being very inexpensive in manufacturing, and disposable use is also possible. In addition, since the device is small, it is advantageous in terms of portability.

It is understood that the term “about” as used herein refers to a range of numbers that one of ordinary skill in the art would consider equivalent to the recited value in terms of achieving the same function or result.

All numerical ranges set forth throughout this specification include their upper and lower values, as well as all narrower numerical ranges falling therein, and all such narrower numerical ranges are considered to be expressly and specifically set forth herein.

The present disclosure may be described in more detail through the examples below.

Example

Throughout this specification, "%" used to indicate the concentration of a specific substance is (weight/weight) % for solid/solid, (weight/volume) % for solid/liquid, and Liquid/liquid is (vol/vol) %.

1. Preparation of anode (catalyst electrode) that activates the oxidation reaction of glucose

Carbon nanotubes (CNT) were added in deionized water (DIW) to prepare 10 uL of a 2 mg/ml CNT solution. Tetrathiafulvalene (TTF) was added in acetonitrile to prepare 10 uL of a 2 mg/ml TTF solution. Glucose oxidase (GOx) was added in phosphate buffered saline (PBS) to prepare 10 μL of a 10 mg/ml GOx solution. Gelatin powder was added in DIW to prepare 10 uL of a 5 wt% gelatin solution. Glutaraldehyde (GA) was added in DIW to prepare 10 mL of a 5 wt% GA solution. All of the above solutions were prepared at room temperature.

Each of the prepared CNT solution, TTF solution, GOx solution, and gelatin solution were sequentially dropped by 10 μL each on a glass carbon electrode (GCE) and dried. After that, the electrode was immersed in the GA solution and cross-linking was performed to bond the amine functional group on the gelatin surface with the aldehyde functional group of GA for 1 minute. Then, it was washed with DIW and dried.

2. Preparation of anode (substrate)

Indium tin oxide (ITO) glass was used as a substrate.

KCl, FeCl ₃ , and potassium hexacyanoferrate (iii) were added in distilled water so that their concentrations were 50 mM KCl, 10 mM FeCl ₃ , and 10 mM potassium hexacyanoferrate (iii), respectively. A total of 20 mL of a solution was prepared KCl, FeCl ₃ , and potassium hexacyanoferrate (iii) are raw materials of Prussian blue, and after mixing them, Prussian blue is produced.

The ITO glass substrate was immersed in the prepared solution and the current density was -25mA/cm ² by electrodeposition for 1 minute to deposit Prussian blue. At this time, parts other than the features were masked and electro-deposited so that Prussian Blue could form the features.

3. Preparation of salt bridge

A saturated KCl solution (1M at 25°C) was prepared, and about 4 g of agar was dissolved in 100 ml of the saturated solution. The solution was heated slowly so as not to boil, and when it became a gel, the solution was filled in a U-shaped glass tube and cooled. On the other hand, electrolyte filter paper was used together. Electrolyte filter paper is manufactured by soaking (physiological saline, potassium chloride). This electrolyte filter paper was arranged to be connected to the substrate, and the filter paper itself was arranged to be connected to the previously prepared glass tube.

4. Check the performance of the blood glucose measurement device

4-1. Preparation of glucose solution

In order to mimic the dermal layer of the body, 5 mL of glucose solutions having concentrations of 0, 5, 10 and 15 mM were prepared by dissolving glucose in PBS.

4-2. Manufacture of blood glucose measurement device

In order to test the performance of the blood glucose measurement apparatus, a simulation structure of the blood glucose measurement apparatus as shown in FIGS. 5 and 6 was prepared. For the simulation structure, the catalyst electrode prepared above was used instead of the microneedle, and the salt bridge was manufactured in the form of a tube and connected between the glucose solution and the substrate. This simulation structure is intended to confirm whether the quantitative measurement of glucose of the blood glucose measurement device according to the present disclosure is possible, and in this embodiment, it is possible to determine whether quantitative analysis of glucose is possible within a short time through the features of the dye on the substrate of the simulation structure. Confirmed.

4-3. Observation of color change according to glucose concentration

15 seconds after starting the measurement, the images of the substrates observed in each glucose solution were observed and shown in FIG. 7 . It can be seen that the number of white bars, that is, the number of features, on the surface of the substrate varies according to the concentration of glucose. That is, it can be seen that quantitative confirmation of glucose is possible within a short time because the number of bars displayed on the substrate is reduced in proportion to the glucose concentration.

In the above embodiment, the performance of quantitative measurement of glucose on the substrate was confirmed through the simulation structure, but even when the catalyst structure and the salt bridge are manufactured in the form of microneedles, the same substrate and the anode substrate are used. I think it will be obtained.

As described above, although the embodiments have been described with reference to the limited drawings, those skilled in the art may apply various technical modifications and variations based on the above. For example, the described techniques are performed in a different order than the described method, and/or the described components of the system, structure, apparatus, circuit, etc. are combined or combined in a different form than the described method, or other components Or substituted or substituted by equivalents may achieve an appropriate result.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (5)

a substrate having a dye deposited thereon;
a biosensor attached to a surface opposite to the surface of the substrate on which the dye is deposited and measuring blood glucose; and
A patch-type blood glucose measurement device comprising a circuit electrically connecting the biosensor and the substrate,
The biosensor includes a plurality of microneedle structures, some of the plurality of microneedle structures contain glucose oxidase and act as a cathode, and the other part of the plurality of microneedle structures is an inert electrolyte Acts as a salt bridge, including
The substrate and the dye act as an anode, the dye exhibits a color change due to the redox reaction of the anode and the cathode, and the substrate uses the degree of color change of the dye displayed on the surface of the substrate to be the biosensor A patch-type blood glucose measurement device that quantitatively displays the amount of blood glucose measured from
The patch-type blood glucose measurement device according to claim 1, wherein the dye is Prussian blue.
The patch-type blood glucose measurement apparatus according to claim 1, wherein the dye is deposited to form a plurality of rectangular-shaped features spaced apart from each other and arranged in parallel on the surface of the substrate.
The patch-type blood glucose measurement device according to claim 3, wherein the color change of the dye is visually observable through the features.
The patch-type blood glucose measurement device according to claim 1, wherein the substrate comprises a flexible material.

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