CN116807469A

CN116807469A - Working electrode of glucose monitoring probe for reducing interference

Info

Publication number: CN116807469A
Application number: CN202310491733.9A
Authority: CN
Inventors: 方骏飞; 郭盼; 韩明松; 夏斌; 赵瑜
Original assignee: Shenzhen Guiji Sensing Technology Co ltd
Current assignee: Shenzhen Guiji Sensing Technology Co ltd
Priority date: 2019-06-24
Filing date: 2020-03-31
Publication date: 2023-09-29
Also published as: CN111248924B; CN211785300U; CN111248924A; CN116473552A

Abstract

The disclosure relates to a working electrode of a glucose monitoring probe with reduced interference, comprising a basal layer, a sensing layer, a semi-permeable membrane and a biocompatible membrane, wherein the basal layer is arranged on a flexible substrate; the sensing layer is formed on the basal layer by coating a sensing layer reagent, can chemically react with glucose in blood or tissue fluid, and comprises a redox polymer, glucose enzyme, carbon nano tubes and a cross-linking agent, wherein amino modification is added to the carbon nano tubes so that the redox polymer and the carbon nano tubes form tight covalent bond combination and are combined with the glucose enzyme, the working voltage required by a working electrode is reduced under the catalysis of the carbon nano tubes, and the glucose enzyme is glucose oxidase; the semi-permeable membrane is formed on the sensing layer and used for controlling the passing rate of glucose molecules; and a biocompatible membrane formed on the semipermeable membrane. According to the present disclosure, a working electrode of a glucose monitoring probe is provided that is capable of reducing interference.

Description

Working electrode of glucose monitoring probe for reducing interference

The application is applied for the date of application31 st 03 th 2020The application number is 202010246108.4 and the application name is Grape Working electrode of sugar monitoring probe and manufacturing method thereofIs a divisional application of the patent application of (2).

Technical Field

The present disclosure relates to the field of glucose monitors, and in particular to a working electrode for a glucose monitoring probe that reduces interference.

Background

The biosensor is an analysis device that tightly combines a biological material, a bio-derived material, or a bio-biomimetic material with an optical, electrochemical, temperature, piezoelectric, magnetic, or micromechanical physicochemical sensor or sensing microsystem. To date, the most commercially successful biosensor is the amperometric enzyme glucose sensor. The market share of amperometric enzyme glucose sensors is almost 85% of the current global market. Amperometric enzyme glucose sensors are used to detect diabetes, the greater their market share, the more people with diabetes are reflected.

Diabetes is a series of metabolic disorder syndromes of sugar, protein, fat, water, electrolyte and the like, and is caused by islet hypofunction, insulin resistance and the like caused by the action of various pathogenic factors such as genetic factors, immune dysfunction, microbial infection, toxins and the like on organisms. If diabetes is not well controlled, it may cause complications such as ketoacidosis, lactic acidosis, chronic renal failure, and retinopathy. With the increasing incidence of diabetes, diabetes has become a public health problem worldwide.

At present, diabetes has no radical treatment method and only control method. For diabetics, if glucose can be monitored continuously in real time on a daily basis, the occurrence of complications such as low glucose and high glucose in insulin-dependent diabetics can be preferentially reduced and lowered.

Typically, glucose monitoring is accomplished by a glucose detector in an amperometric glucose sensor. The sensing probe of a glucose meter is typically implanted in the body to monitor the glucose concentration in the interstitial fluid and the surrounding blood flow, the metabolic rate, and the rate of change of the glucose concentration in the blood vessel. Studies have shown that the change in glucose concentration in interstitial fluid is typically delayed from the change in glucose concentration in blood by 2-45 minutes with an average delay of about 6.7 minutes. However, when the glucose concentration in the blood starts to decrease, the glucose concentration in the tissue fluid decreases earlier than the glucose in the blood, indicating that the decrease in the glucose concentration in the tissue fluid can be predicted for an upcoming low glucose.

With the development of the technology level, various portable glucose detectors enter eyes of people, and particularly, certain implantable continuous glucose monitoring devices are favored by diabetics and various hospitals. However, implantable continuous glucose meters tend to have a long life and are susceptible to reduced sensitivity due to immune responses in the body and other impurities in the blood. Therefore, how to better construct a detection device, prolonging the service life of a sensing probe of a glucose detector and reducing the influence of other factors become the biggest problem at present.

Disclosure of Invention

The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a working electrode of a glucose monitoring probe that extends the service life of the probe, reduces interference, and improves the sensitivity to glucose reaction, and a method for manufacturing the same.

To this end, an aspect of the present disclosure provides a working electrode of a glucose monitoring probe, characterized in that the working electrode is provided with: a base layer disposed on the flexible substrate; a sensing layer formed on the base layer by coating a sensing layer reagent capable of chemically reacting with glucose in blood or interstitial fluid, the sensing layer reagent including a metal polymer, a glucose enzyme, a carbon nanotube and a cross-linking agent, the carbon nanotube adsorbing the metal polymer and the glucose enzyme, and adding an amino modification to the carbon nanotube to tightly form covalent bonds between the metal polymer and the carbon nanotube and to bind with the glucose enzyme; a semipermeable membrane formed on the sensor layer and controlling the passage rate of glucose molecules; and a biocompatible membrane formed on the semipermeable membrane.

In the working electrode of the glucose monitoring probe according to an aspect of the present disclosure, the sensing layer includes carbon nanotubes. Under the condition, the catalytic action of the carbon nano tube on the glucose reaction reduces the working voltage required by the normal working of the working electrode, and reduces the interference of current generated by electrochemical reaction of electroactive substances under partial high voltage on the working electrode; meanwhile, the response sensitivity of the probe to glucose is improved, the linear range of the response of the probe to glucose is also enlarged, and the service life of the probe is prolonged.

In addition, in the working electrode of the glucose monitoring probe according to an aspect of the present disclosure, optionally, in the sensing layer reagent, the mass percentage of the carbon nanotubes is 1 to 50%. Thus, the metal polymer in the sensing layer reagent can more easily form covalent bonds with the carbon nanotubes.

In addition, in the working electrode of the glucose monitoring probe according to an aspect of the present disclosure, optionally, the semipermeable membrane includes a diffusion control layer that controls diffusion of glucose molecules. In this case, the proportion of glucose components in the tissue fluid or blood entering the semipermeable membrane is blocked, and excessive glucose molecules are prevented from reacting with the working electrode, resulting in a decrease in the life of the glucose monitoring probe.

Additionally, in the working electrode of the glucose monitoring probe according to an aspect of the present disclosure, optionally, the semi-permeable membrane includes an anti-interference layer that blocks non-glucose substances. In this case, the tissue fluid or other components in the blood are blocked from entering the semipermeable membrane, and other electroactive substances which can also generate current are prevented from affecting the working electrode, so that an inaccurate glucose detection result is caused.

In addition, in the working electrode of the glucose monitoring probe according to an aspect of the present disclosure, optionally, the thickness of the sensing layer is 0.1 μm to 100 μm. Thus, sufficient glucose can be provided under the premise of sufficient reaction and firm attachment.

Yet another aspect of the present disclosure provides a glucose monitoring probe, comprising a working electrode, a counter electrode, and a reference electrode, which are arranged in a dispersed manner, the working electrode having: a base layer disposed on the flexible substrate; a sensing layer formed on the base layer by coating a sensing layer reagent capable of chemically reacting with glucose in blood or interstitial fluid, the sensing layer reagent including a redox polymer, a glucose enzyme, carbon nanotubes and a cross-linking agent, the carbon nanotubes adsorbing the redox polymer and the glucose enzyme, adding an amino modification to the carbon nanotubes to tightly form covalent bond bonds between the redox polymer and the carbon nanotubes, and bonding with the glucose enzyme; a semipermeable membrane formed on the sensing layer, the semipermeable membrane including an anti-interference layer that blocks non-glucose substances and a diffusion control layer that controls diffusion of glucose molecules; and a biocompatible membrane formed on the semipermeable membrane.

In a glucose monitoring probe according to yet another aspect of the present disclosure, the sensing layer includes a redox polymer. In this case, the working voltage required by the normal operation of the working electrode is reduced, so that the interference of current generated by electrochemical reaction of the electroactive substances under partial high voltage on the working electrode is reduced; meanwhile, the response sensitivity of the probe to glucose is improved, the linear range of the response of the probe to glucose is also enlarged, and the service life of the probe is prolonged.

In addition, in the working electrode of the glucose monitoring probe according to an aspect of the present disclosure, optionally, in the sensing layer reagent, the redox polymer is a metal redox polymer. Thus, the metal redox polymer can participate in the redox reaction.

In addition, in the working electrode of the glucose monitoring probe according to an aspect of the present disclosure, the metal redox polymer may be optionally selected from at least one of poly (vinylferrocene), quaternized poly (4-vinylpyridine) of ferricyanide, quaternized poly (1-vinylimidazole) of ferricyanide, quaternized poly (4-vinylpyridine) of ferrocyanide, quaternized poly (1-vinylimidazole) of ferrocyanide, osmium 2,2 '-bipyridine complex coordinated to poly (1-vinylimidazole), osmium 2,2' -bipyridine complex coordinated to poly (4-vinylpyridine), cobalt 2,2 '-bipyridine complex coordinated to poly (1-vinylimidazole), or cobalt 2,2' -bipyridine complex coordinated to poly (4-vinylpyridine). Thus, the metal redox polymer can participate in redox reactions through covalent, coordination or ionic bonds.

Another aspect of the present disclosure provides a method for manufacturing a working electrode of a glucose monitoring probe, including: preparing a flexible substrate; forming a base layer on the flexible substrate; preparing a sensing layer reagent comprising a redox polymer, a glucose enzyme, a carbon nanotube and a cross-linking agent; coating the sensing layer reagent on the substrate layer and forming a sensing layer; forming a semipermeable membrane for controlling the passage rate of glucose molecules on the sensing layer; and forming a biocompatible membrane over the semipermeable membrane.

In another aspect of the present disclosure, carbon nanotubes are included in the sensing layer. Therefore, the working voltage of the working electrode is reduced, the interference of other factors is reduced, the response sensitivity of the probe to glucose is improved, the linear range of the response of the probe to glucose is also enlarged, and the service life of the probe is prolonged.

In addition, in the method for manufacturing a working electrode of a glucose monitoring probe according to the present disclosure, optionally, in the sensing layer reagent, the mass percentage of the carbon nanotubes is 1 to 50%. This can promote the reaction of the glucose with the enzyme.

According to the present disclosure, it is possible to provide a working electrode of a glucose monitoring probe that extends the service life of the probe, reduces interference, and improves the sensitivity to glucose reaction, and a method of manufacturing the same.

Drawings

Fig. 1 is a schematic diagram showing a state of use of a glucose monitoring probe according to an embodiment of the present disclosure.

Fig. 2 is a schematic diagram showing the structure of a glucose monitoring probe according to an embodiment of the present disclosure.

Fig. 3 is a schematic view showing a structure of the glucose monitoring probe of fig. 2 in a bent state.

Fig. 4 is a schematic diagram showing the structure of a working electrode of a glucose monitoring probe according to an embodiment of the present disclosure.

Fig. 5 is a schematic diagram showing carbon nanotube adsorption of glucose enzyme by a glucose monitoring probe according to an embodiment of the present disclosure.

Fig. 6 is a schematic diagram illustrating glucose reaction of a glucose monitoring probe with tissue in accordance with an embodiment of the present disclosure.

Fig. 7 is a schematic diagram showing the structure of a semipermeable membrane of a working electrode of a glucose monitoring probe according to an embodiment of the present disclosure.

Fig. 8 is a flowchart showing a method of manufacturing a working electrode of a glucose monitoring probe according to an embodiment of the present disclosure.

Fig. 9 is a flowchart showing a method of manufacturing a semipermeable membrane of a working electrode of a glucose monitoring probe according to an embodiment of the present disclosure.

Detailed Description

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same members are denoted by the same reference numerals, and overlapping description thereof is omitted. In addition, the drawings are schematic, and the ratio of the sizes of the components to each other, the shapes of the components, and the like may be different from actual ones.

In addition, headings and the like referred to in the following description of the disclosure are not intended to limit the disclosure or scope thereof, but rather are merely indicative of reading. Such subtitles are not to be understood as being used for segmenting the content of the article, nor should the content under the subtitle be limited only to the scope of the subtitle.

Fig. 1 is a schematic diagram showing a state of use of a glucose monitoring probe according to an embodiment of the present disclosure. Fig. 2 is a block diagram illustrating a glucose monitoring probe according to an embodiment of the present disclosure. Fig. 3 is a schematic view showing a structure of the glucose monitoring probe of fig. 2 in a bent state.

In the present embodiment, the glucose monitoring probe 1 may be referred to as an implantable glucose monitoring probe 1, a glucose monitor probe 1, or a probe 1.

In this embodiment, the portable glucose monitor G may include a glucose monitoring probe 1 and an electronic system 2 connected to the glucose monitoring probe 1. By implanting the glucose monitoring probe 1 of the portable glucose monitor G to a human body such as a body surface of a human body, the glucose monitoring probe 1 is brought into contact with a tissue fluid or blood on the body surface, whereby a sensing signal of the tissue fluid related to a glucose concentration can be sensed by the glucose monitoring probe 1, and a corresponding glucose concentration can be obtained by transmitting the glucose concentration signal to the electronic system 2.

Specifically, a portion (particularly, a sensing portion) of the glucose monitoring probe 1 may be implanted on, for example, a body surface of a human body to be in contact with interstitial fluid in the body. In addition, another part of the glucose monitoring probe 1 is also connected to an electronic system 2 located outside the body surface. In operation of the portable glucose monitor G, the glucose monitoring probe 1 reacts with interstitial fluid or blood in the body to generate a sensing signal (e.g., a current signal) and transmits the sensing signal to the electronic system 2 of the body surface, which electronic system 2 processes to obtain a glucose concentration. Although fig. 1 shows the position where the glucose monitoring probe 1 is disposed on the arm, the present embodiment is not limited to this, and the glucose monitoring probe 1 may be disposed on the abdomen, waist, leg, or the like, for example.

In the present embodiment, the glucose monitoring probe 1 may directly detect glucose in blood or may detect glucose in interstitial fluid. Further, the glucose concentration of the interstitial fluid is strongly correlated with the glucose concentration of blood, and the glucose concentration of blood can be obtained from the glucose of the interstitial fluid.

In the present embodiment, the glucose monitoring probe 1 may include a substrate S, and a working electrode 10, a reference electrode 20, and a counter electrode 30 (see fig. 2) provided on the substrate S. The glucose monitoring probe 1 further includes a contact 41 connected to the working electrode 10 via a lead, a contact 42 connected to the reference electrode 20 via a lead, and a contact 43 connected to the counter electrode 30 via a lead. The contacts 41, 42, 43 are all electrical contacts. In some examples, glucose monitoring probe 1 may be connected to electronic system 2 via contacts 41, 42, and 43.

In some examples, the substrate S may be a flexible substrate. The flexible substrate may be generally made of at least one of Polyethylene (PE), polypropylene (PP), polyimide (PI), polystyrene (PS), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). In addition, in other examples, the flexible substrate may also be made substantially of metal foil, ultra-thin glass, single-layer inorganic film, multi-layer organic film, multi-layer inorganic film, or the like.

In some examples, the substrate S may also be a non-flexible substrate. The inflexible substrate may generally comprise a less conductive ceramic, alumina, or silica, or the like. In this case, the glucose monitoring probe 1 having an inflexible substrate may also have sharp points or sharp edges, thereby enabling implantation of the glucose monitoring probe 1 into a body surface (e.g., shallow skin, etc.) without the need for an auxiliary implantation device (not shown).

In the present embodiment, for convenience of explanation, the glucose monitoring probe 1 may be divided into a connection portion 1a and an implantation portion 1b (see fig. 3). The line A-A' in fig. 3 shows approximately the location of the skin when the glucose monitoring probe 1 is implanted on the body surface of the tissue, the connection portion 1a being located outside the body surface and the implantation portion 1b being implanted inside the body surface.

In addition, in some examples, the connection portion 1a and the implantation portion 1b may both include a flexible substrate, but the present embodiment is not limited thereto, and for example, only the implantation portion 1b may include a flexible substrate, and the connection portion 1a may include a non-flexible substrate such as a rigid substrate.

In the present embodiment, the implanted portion 1b of the glucose monitoring probe 1 may be provided to an auxiliary puncture needle (not shown), and the implanted portion 1b may be separable from the puncture needle. Specifically, the puncture needle may be inserted into a tissue (e.g., a skin superficial layer), and then the puncture needle is pulled out and separated from the implanted portion 1b of the glucose monitoring probe 1, whereby the implanted portion 1b is left in the skin superficial layer and the electronic system 2 is brought into close contact with the skin surface, and the connection portion 1a (see fig. 3) of the glucose monitoring probe 1 is connected to and located on the skin surface with the electronic system 2. Here, the electronic system 2 may be adhered to the skin surface by an adhesive provided on the substrate S.

In some examples, the puncture needle as an auxiliary implantation may have a notch, and the implantation portion 1b is placed in the notch of the puncture needle. Wherein the puncture needle may be made of stainless steel. In this case, the risk of using the puncture needle can be reduced, and the puncture needle has sufficient hardness to facilitate the penetration of the skin. Is beneficial to the use of patients. Additionally, in some examples, the spike may also be made of plastic, glass, or metal.

In this embodiment, an auxiliary implantation device (not shown), such as a needle aid, may be used to pierce the needle into the skin. In this case, the penetration depth can be pre-set using, for example, a needle aid, and the pain of the user can be reduced by achieving rapid penetration and painless penetration using the needle aid. In addition, the auxiliary implantation device can be conveniently operated by one hand. However, the present embodiment is not limited thereto, and, for example, when the glucose monitoring probe 1 is a rigid substrate as described above, the glucose monitoring probe 1 may be implanted in the skin without using a puncture needle.

In the present embodiment, the depth to which the glucose monitoring probe 1 is implanted subcutaneously is determined according to the location to be penetrated, and the implantation depth may be about 10mm to 15mm when the fat layer is thick, for example, the abdomen of a human body. The fat layer is thinner and implanted shallower, for example at the arm, the implantation depth may be about 5mm to 10mm.

Fig. 4 is a schematic diagram showing the structure of the working electrode 10 of the glucose monitoring probe 1 according to the embodiment of the present disclosure. Fig. 5 is a schematic diagram showing adsorption of glucose by carbon nanotubes of the glucose monitoring probe 1 according to the embodiment of the present disclosure. Fig. 6 is a schematic diagram showing glucose reaction of the glucose monitoring probe 1 and tissue according to the embodiment of the present disclosure. Fig. 7 is a schematic diagram showing the structure of a semipermeable membrane of the working electrode 10 of the glucose monitoring probe 1 according to the embodiment of the present disclosure.

In the present embodiment, as described above, the implanted portion 1b of the glucose monitoring probe 1 includes the working electrode 10 (see fig. 2 and 3).

In this embodiment, in some examples, the working electrode 10 may be provided with a base layer 110, a sensing layer 120, a semi-permeable membrane 130, and a biocompatible membrane 140 (see fig. 4). In some examples, the base layer 110, the sensing layer 120, the semipermeable membrane 130, and the biocompatible membrane 140 may be sequentially laminated.

In this embodiment, the base layer 110 has conductivity. In some examples, the base layer 110 may be made of at least one selected from gold, glassy carbon, graphite, silver chloride, palladium, titanium, iridium. In this case, the base layer 110 can have good conductivity, and the electrochemical reaction of the base layer 110 can be suppressed, whereby the stability of the base layer 110 can be improved.

In this embodiment, the base layer 110 may be provided on the substrate S by a deposition or plating method in some examples. In some examples, the method of deposition may include physical vapor deposition, chemical vapor deposition, and the like. Plating methods may include electroplating, electroless plating, vacuum plating, and the like. In addition, in some examples, the base layer 110 may also be provided on the substrate S by screen printing, extrusion, or electrodeposition, among others.

In this embodiment, the base layer 110 may be disposed on a flexible substrate. In this case, the flexible substrate makes the whole product lightweight, has strong impact resistance, and reduces foreign body sensation after implantation. In other examples, the base layer 110 may also be disposed on a rigid substrate.

In the present embodiment, the sensing layer 120 may be formed on the base layer 110 by coating a sensing layer reagent so as to be capable of chemically reacting with glucose. In some examples, the sensing layer reagent may include a redox polymer, a glucose enzyme, carbon nanotubes 121, and a cross-linking agent. In this case, the sensing layer 120 includes the carbon nanotubes 121, and the catalytic action of the carbon nanotubes 121 on the glucose reaction reduces the operating voltage required for the working electrode 10 to operate normally, so that the interference of the current generated by the electrochemical reaction of the electroactive material at a part of high voltage on the working electrode 10 can be reduced.

In some examples, the redox polymer may have covalent, coordination, or ionic bonds. In some examples, the redox polymer may be a metal polymer that functions as a redox, i.e., a metal redox polymer. The metal polymer may be, for example, a metal polymer having covalent bonds, coordinate bonds, or ionic bonds. In some examples, the metal polymer may be selected from at least one of poly (vinylferrocene), quaternized poly (4-vinylpyridine) of ferricyanide, quaternized poly (1-vinylimidazole) of ferricyanide, quaternized poly (4-vinylpyridine) of ferrocyanide, quaternized poly (1-vinylimidazole) of ferrocyanide, coordination of osmium 2,2 '-bipyridine complex to poly (1-vinylimidazole), coordination of osmium 2,2' -bipyridine complex to poly (4-vinylpyridine), coordination of cobalt 2,2 '-bipyridine complex to poly (1-vinylimidazole), or coordination of 2,2' -bipyridine complex to poly (4-vinylpyridine).

Generally, carbon nanotubes mainly comprise concentric tubes of several to several tens layers of carbon atoms arranged in a hexagonal shape, and the layers are kept at a constant distance from each other, about 0.34nm, and the diameter is generally 2 to 20nm.

In some examples, as shown in fig. 5, carbon nanotubes 121 may be hollow columnar. Specifically, the carbon nanotubes 121 may have a cylindrical shape, an elliptical cylindrical shape, or the like. In addition, the carbon nanotubes 121 have a strong adsorption capacity for organic matters due to their large surface area and surface hydrophobicity.

In the sensing layer 120, since the carbon nanotubes 121 may adsorb glucose and a redox polymer (e.g., a metal polymer), the carbon nanotubes 121 can sufficiently contact and catalyze a reaction during a glucose reaction, so that the glucose reaction can be more effectively promoted.

In the present embodiment, the carbon nanotubes 121 may be dissolved in a solvent to be added to the sensing layer reagent. Thereby, the sensor layer 120 including the carbon nanotubes 121 can be conveniently manufactured.

In some examples, the mass percent of carbon nanotubes 121 in the sensing layer reagent may be 1 to 50%. This can promote the reaction of the glucose with the enzyme. In some examples, the mass percent of carbon nanotubes 121 may be 5 to 10% for the purpose of better matching the coating process. Thus, the effectiveness of the sensing layer reagent can be ensured and the corresponding promotion effect can be achieved. Specifically, the mass percentage of the carbon nanotubes 121 may be 5%, 6%, 7%, 8%, 9% or 10%.

In some examples, the sensing layer reagent may form the sensing layer 120 by at least one process of spin coating, dip-coating, drop-coating, or spray-coating.

In the present embodiment, the sensing layer 120 may be a glucose oxidase sensing layer or a glucose dehydrogenase sensing layer.

In the following, referring to FIG. 6, glucose oxidase (GO _X (FAD) and redox polymer (MED) _red ) The reaction occurring in the glucose sensing layer 120 is illustrated by way of example.

For example, after working electrode 10 is implanted subcutaneously (e.g., subcutaneously in an arm), glucose sensing layer 120 in working electrode 10 contacts interstitial fluid in the body when GO _X (FAD) when it encounters glucose in tissue, the following reaction occursThe method comprises the following steps:

glucose+GOx (FAD) →glucolactone+GOx (FADH) ₂ ) … … reaction type (I)

GOx(FADH ₂ )+MED _ox →GOx(FAD)+MED _red … … reaction type (II)

MED _red -e ^- →MED _ox … … reaction type (III)

As can be seen during the above reaction, the redox polymer oxidation state (MED _ox ) Is reduced to MED _red ，MED _red Oxidized to MED by applying an operating voltage _ox However, if MED _red Cannot be oxidized to MED rapidly _ox Causes MED _ox The shortage is that the reaction rate of the reaction formula (II) and the reaction formula (I) is limited by MED _ox The reaction to tissue glucose is slowed in amount, resulting in failure of the glucose monitoring probe 1. Therefore, by adding the carbon nanotubes 121 in the sensing layer 120, MED can be greatly accelerated and made at a lower voltage under the action of the carbon nanotubes 121 as a catalyst _red Oxidized to MED _ox 。

By the above-mentioned reaction formulae (I) to (III), the reaction with tissue glucose can be continued. In addition, by using the carbon nanotubes 121, it is possible to accelerate the progress of the reaction (III) and reduce the voltage required to be applied during the reaction, thereby contributing to an improvement in the sensitivity of the glucose monitoring probe 1, an extension in the use time of the glucose monitoring probe 1, and a low operating voltage. In other words, the carbon nanotubes 121 can continuously obtain high-sensitivity sensing signals of tissue glucose, prolong the service time of the glucose monitoring probe 1, and simultaneously the low operating voltage is beneficial to improving the anti-interference performance.

In addition, in some examples, amino modifications may also be added to the carbon nanotubes 121 in the sensing layer reagent. In this case, the metal polymer and the carbon nanotube 121 can be tightly bound to each other by covalent bonds, and thus, the binding with the glucose enzyme can be more stable. In addition, the addition of amino modification to the carbon nanotubes 121 can also allow the redox polymer and the carbon nanotubes 121 to tightly form covalent bonds.

In other examples, graphene, porous titanium dioxide, or a conductive organic salt may also be added to the sensing layer reagent. This can promote the reaction of the glucose with the enzyme.

In the present embodiment, the glucose monitoring probe 1 is implanted in the skin of a human body, and glucose in blood can be continuously sampled and converted into a corresponding current signal, which is transmitted to the external electronic system 2.

In this embodiment, the thickness of the sensing layer 120 may be about 0.1 μm to 100 μm, preferably about 2 μm to 10 μm. In one example, the thickness of the sensing layer 120 may be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm. In this case, the thickness of the glucose oxidase or dehydrogenase is controlled within a certain degree, so that the problems that the adhesion force is reduced due to excessive glucose oxidase or dehydrogenase, materials fall off in vivo, insufficient reaction is caused by insufficient glucose oxidase or dehydrogenase, and normal glucose concentration information cannot be fed back and the like are avoided.

In the present embodiment, as shown in fig. 4 and 7, the semipermeable membrane 130 may be distributed on the sensing layer 120, that is, the semipermeable membrane 130 may be disposed on the sensing layer 120.

In addition, in the present embodiment, as shown in fig. 7, the semipermeable membrane 130 may include a diffusion control layer 131 and an anti-interference layer 132 laminated on the diffusion control layer 131. In the semipermeable membrane 130, the diffusion controlling layer 131 can control the diffusion of glucose molecules, and the anti-interference layer 132 can block the diffusion of non-glucose substances. Thus, the interstitial fluid or blood components passing through the semipermeable membrane 130 may be reduced, and then the interfering substances may be blocked outside the semipermeable membrane 130 by the anti-interference layer 132. Common interferents may include uric acid, ascorbic acid, acetaminophen, and the like, which are ubiquitous in the body.

In other examples, not limited to the example of fig. 7, in the semipermeable membrane 130, the diffusion control layer 131 may also be laminated on the tamper resistant layer 132. In this case, too, the interference of impurities to the working electrode 10 can be reduced, the accuracy of the detection result can be improved, and the service life of the glucose monitoring probe 1 can be prolonged.

In this embodiment, the semipermeable membrane 130 can control the passage rate of glucose molecules, i.e., the semipermeable membrane 130 can limit the number of glucose molecules in the interstitial fluid or blood that reach the sensing layer 120. Specifically, the diffusion control layer 131 of the semipermeable membrane 130 is capable of effectively reducing the amount of glucose diffused to the sensing layer 120 by a certain ratio.

In the present embodiment, the diffusion control layer 131 can reduce the magnification of the entering substance by 10 to 100 times, preferably 30 to 80 times, and for example, the magnification may be 30, 40, 50, 60, 70, or 80 times. In this case, the amount of glucose diffusing into the sensing layer 120 can be reduced, and a sufficient amount of glucose oxidase or dehydrogenase and other substances participating in the reaction can be ensured, and the glucose concentration becomes a factor mainly limiting the magnitude of the electrode current, so that the magnitude of the current can accurately reflect the concentration of glucose, and the linear range of the glucose monitoring probe 1 can be increased to a large extent.

In this embodiment, the biocompatible membrane 140 may be disposed on the semipermeable membrane 130 (see fig. 4).

In some examples, the biocompatible film 140 may be made of a plant material. The plant material may be sodium alginate, tragacanth, pectin, acacia, xanthan gum, guar gum, agar, etc. or natural material derivatives. Wherein the natural material derivative may include: starch derivatives, cellulose derivatives, and the like.

In other examples, the biocompatible film 140 may also be made of synthetic materials. The synthetic material may be a polyolefin: povidone, polyvinyl alcohol, polyisobutylene pressure sensitive adhesives, ethylene-vinyl acetate copolymers, and the like; polyacrylic acids may also be used: acrylic resin, carboxyvinyl-sucrose, carboxyvinyl-pentaerythritol copolymer, polyacrylate pressure sensitive adhesive, and the like; polyoxyethylene species may also be used: polyesters such as polyoxyethylene fatty acid ester and polyoxyethylene-polyoxypropylene copolymer: polylactic acid, polyglycolide-lactide, polynosilane sebacate, polycyanoalkylamino ester, polyether polyurethane, etc. Thus, the immune response of the human body to the glucose monitoring probe 1 can be inhibited, and the service life of the glucose monitoring probe 1 is prolonged.

Additionally, in some examples, the semipermeable membrane 130 may also be biocompatible. Thus, the use of the biocompatible film 140 can be omitted, and the manufacturing cost can be reduced.

In other examples, the permeability of the formed membrane to the analyte of interest may be adjusted by a modifying agent. For example, the hydrophilic modifier includes: polyethylene glycol, hydroxyl or polyhydroxy modifier. Thus, the biocompatibility of the polymer-formed film can be increased, instead of the biocompatible film 140.

In this embodiment, the biocompatible film 140 may cover the entire glucose monitoring probe 1. In some examples, the biocompatible film 140 may cover only the implanted portion 1b of the glucose monitoring probe 1 implanted in the body. This can reduce the use of raw materials.

In the present embodiment, the use period of the glucose monitoring probe 1 may be 1 to 24 days, preferably 7 to 14 days. In addition, as described above, the semipermeable membrane 130 can limit the entry of a part of glucose molecules and electroactive interfering substances, can effectively expand the linear range of the glucose monitoring probe 1, can allow the sensing layer 120 to react with glucose oxidase or dehydrogenase more effectively, and can keep the life cycle of the glucose monitoring probe 1 stable.

The glucose monitoring probe 1 may be used for ordinary tests, such as a single test or a short-time test. For example, the time of monitoring may be 1 hour to 24 hours or 24 hours to 36 hours.

In addition, the addition of the biocompatible film 140 can keep the usage period of the glucose monitoring probe 1 at 1 to 24 days, for example, 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, 14 days, 15 days, 16 days, 17 days, 18 days, 19 days, 20 days, 21 days, 22 days, 23 days, 24 days, thereby enabling the user to conveniently select the glucose monitor G of the glucose monitoring probe 1 having different usage periods according to different demands (e.g., price, etc.).

In the present embodiment, as described above, the glucose monitoring probe 1 may further include a reference electrode 20 and a counter electrode 30 (see fig. 2). Specifically, as shown in fig. 3, the implanted portion 1b of the glucose monitoring probe 1 may include a reference electrode 20 and a counter electrode 30.

In the present embodiment, the glucose monitoring probe 1 implanted in the skin can generate a current signal by performing an oxidation-reduction reaction between glucose oxidase or dehydrogenase in the working electrode 10 and glucose in tissue fluid or blood, and forming a circuit with the counter electrode 30.

In this embodiment, the reference electrode 20 may be at a known and fixed potential difference with the interstitial fluid or blood. In this case, the potential difference between the working electrode 10 and the tissue fluid or blood can be measured by the potential difference formed by the reference electrode 20 and the working electrode 10, thereby accurately grasping the voltage generated by the working electrode 10. Thus, the electronic system 2 can automatically adjust and maintain the voltage at the working electrode 10 stable according to the preset voltage value, so as to ensure that the measured current signal can accurately reflect the glucose concentration value.

In addition, in the present embodiment, the working electrode 10, the reference electrode 20, and the counter electrode 30 of the implant part 1b are disposed in a dispersed manner, but the embodiment of the present disclosure is not limited thereto, and may include a side-by-side (side-by-side) arrangement.

In the present embodiment, the glucose monitoring probe 1 is not limited to a planar probe, but may be a linear probe, a probe having stacked electrodes or layered electrodes, or a probe having coplanar electrodes in which electrodes are disposed on the same plane.

In some examples, the reference electrode 20 may not be used when the variation in potential difference between the working electrode 10 and the interstitial fluid or blood does not fluctuate much.

In the present embodiment, the counter electrode 30 may be made of platinum, silver chloride, palladium, titanium, or iridium. Thus, the electrochemical reaction at the working electrode 10 can be unaffected with good conductivity. However, the present embodiment is not limited thereto, and in other examples, the counter electrode 30 may be made of at least one selected from gold, glassy carbon, graphite, silver chloride, palladium, titanium, or iridium. Thus, the influence on the working electrode 10 can be reduced with good conductivity.

In addition, in some examples, the same materials may be used for the working electrode 10, the counter electrode 30, and the reference electrode 20.

In the present embodiment, the glucose monitoring probe 1 may include two or three or more electrodes. For example, the glucose monitoring probe 1 may include only two electrodes of the working electrode 10 and the counter electrode 30, and in addition, the glucose monitoring probe 1 may include additional reference electrodes in addition to the working electrode 10, the reference electrode 20, and the counter electrode 30. In this case, it is possible to more accurately obtain the potential difference of the working electrode 10 and grasp the working electrode 10 voltage, thereby obtaining more accurate current.

In the present embodiment, as described above, the connection portion 1a of the glucose monitoring probe 1 includes a plurality of contacts (contacts). The number of contacts is equal to the number of electrodes of the implanted portion 1b of the glucose monitoring probe 1. The contact is connected with the electrode of the implanted portion 1b by a lead wire.

In the present embodiment, as shown in fig. 3, there are three electrodes in the implanted portion 1b of the glucose monitoring probe 1. Accordingly, the connection portion 1a includes three contacts (contacts), which are a contact 41, a contact 42, and a contact 43, respectively. However, the present embodiment is not limited thereto, and for example, the number of electrodes of the implanted portion 1b may be two or more than four electrodes, and accordingly, the connection portion 1a may include two or more than four contacts (contacts).

In the present embodiment, the contact 41, the contact 42, and the contact 43 may each be disc-shaped, and may be formed as a pad, for example. In addition, the contact 41, the contact 42, and the contact 43 may be formed as pads. In other examples, contacts 41, 42, and 43 may also be rectangular, oval, or other irregular shapes.

In the present embodiment, the current signal generated by the implanted part 1b of the glucose monitoring probe 1 may be transmitted to the contact of the connecting part 1a through the base layer 110 and the transmission wire. That is, the implanted portion 1b of the glucose monitoring probe 1 is connected to the connection portion 1a, and the connection portion 1a is connected to the electronic system 2 via a plurality of contacts, and therefore, the current signal obtained by the working electrode 10 is transmitted to the electronic system 2 via the contacts of the connection portion 1a for analysis. The electronic system 2 may analyze the current signal to obtain a glucose concentration signal.

In addition, in some examples, the electronic system 2 may transmit to an external reader device via wireless communication means, such as bluetooth, wifi, etc. A reading device (not shown) may receive the glucose concentration signal emitted by the electronic system 2 and display a glucose concentration value. Further, since the glucose monitoring probe 1 according to the present embodiment can realize continuous monitoring, the glucose concentration value of the human body can be continuously monitored for a long period of time (for example, 1 to 24 days). Additionally, in some examples, the reading device may be a reader or a cell phone APP.

In addition, in the present embodiment, the glucose monitoring probe 1 and the electronic system 2 may not require calibration during in vivo use. In addition, the glucose monitoring probe 1 and the electronic system 2 may be calibrated in advance at the time of shipment. Thereby, the trouble of the user needing to calibrate the monitoring system with the finger blood at regular intervals can be eliminated and the potential sources of monitoring module reading errors during use are reduced.

In this embodiment, the electronic system 2 may be made of a flexible PCB and a flexible battery. Thus, the skin can be closely attached, and the influence on the daily life of the user can be reduced. In some examples, the electronic system 2 may have a circular shape in shape. In addition, in some examples, the electronic system 2 may also have a waterproof enclosure with waterproof band-aid, thereby enabling the user to use without affecting daily activities such as swimming or bathing.

In the present embodiment, the glucose monitoring probe 1 can obtain the glucose concentration in the tissue fluid or blood. However, the present embodiment is not limited thereto, and, for example, by changing the sensor layer 120 on the glucose monitoring probe 1, other body fluid component data other than glucose may be obtained, and the body fluid component may be, for example, acetylcholine, amylase, bilirubin, cholesterol, chorionic gonadotropin, creatine kinase, creatine, creatinine, DNA, fructosamine, glucose, glutamine, growth hormone, ketone body, lactate, oxygen, peroxide, prostate specific antigen, prothrombin, RNA, thyroid stimulating hormone, troponin, or the like.

In other examples, the concentration of a drug in the body fluid may also be monitored, for example, antibiotics (e.g., gentamicin, vancomycin, etc.), digitoxin, digoxin, theophylline, warfarin (warfarin), and the like.

In the present embodiment, first, the sensing layer 120 is formed on the base layer 110 of the working electrode 10, then the semipermeable membrane 130 coating is formed on the sensing layer 120, and finally the biocompatible membrane 140 layer is formed on the semipermeable membrane 130 coating. Therefore, the service life of the glucose monitoring probe 1 is prolonged, interference of other factors is reduced, and the reaction speed of the glucose monitoring probe 1 to glucose is improved.

Hereinafter, a method for manufacturing the working electrode 10 of the glucose monitoring probe 1 will be described in detail with reference to the accompanying drawings.

Fig. 8 is a flowchart showing a method of manufacturing the working electrode 10 of the glucose monitoring probe 1 according to the embodiment of the present disclosure. Fig. 9 is a flowchart showing a method of manufacturing the semipermeable membrane 130 of the working electrode 10 of the glucose monitoring probe 1 according to the embodiment of the present disclosure.

In the present embodiment, the method for manufacturing the working electrode 10 of the glucose monitoring probe 1 may include (see fig. 8): preparing a flexible substrate, and forming a base layer 110 on the flexible substrate (step S110); preparing a sensing layer 120 reagent including a redox polymer, a glucose enzyme, a carbon nanotube 121, and a cross-linking agent (step S120); coating a sensing layer reagent on the base layer 110 and forming a sensing layer 120 (step S130); forming a semipermeable membrane 130 for controlling the passing rate of glucose molecules on the sensing layer 120 (step S140); and a biocompatible film 140 is formed on the semipermeable membrane 130 (step S150). In this case, the carbon nanotubes 121 are contained in the sensing layer 120. Thus, the working voltage of the working electrode 10 is reduced, the interference of other factors is reduced, the response sensitivity of the probe to glucose is improved, the linear range of the glucose monitoring probe 1 responding to glucose can be enlarged, and the service life of the probe is prolonged.

As described above, in step S110, a flexible substrate is prepared, and the base layer 110 is formed on the flexible substrate. In some examples, the substrate layer 110 may also be fabricated by one or more of electroplating, evaporation, printing, or extrusion.

In this embodiment, in some examples, in step S130, the sensing layer 120 may be a glucose oxidase sensing layer or a glucose dehydrogenase sensing layer.

In some examples, in step S110, the redox polymer may have a covalent bond, a coordination bond, or an ionic bond. In some examples, the redox polymer may be a metal polymer that functions as a redox. The metal polymer may be, for example, a metal polymer having covalent bonds, coordinate bonds, or ionic bonds. In some examples, the metal polymer may be selected from at least one of poly (vinylferrocene), quaternized poly (4-vinylpyridine) of ferricyanide, quaternized poly (1-vinylimidazole) of ferricyanide, quaternized poly (4-vinylpyridine) of ferrocyanide, quaternized poly (1-vinylimidazole) of ferrocyanide, coordination of osmium 2,2 '-bipyridine complex to poly (1-vinylimidazole), coordination of osmium 2,2' -bipyridine complex to poly (4-vinylpyridine), coordination of cobalt 2,2 '-bipyridine complex to poly (1-vinylimidazole), or coordination of 2,2' -bipyridine complex to poly (4-vinylpyridine).

In the manufacturing method according to the present embodiment, as shown in fig. 9, step S140 may include forming the anti-interference layer 132 on the sensing layer 120 (step S141), and then forming the diffusion control layer 131 on the anti-interference layer (step S142). Thus, the tissue fluid or blood component passing through the semipermeable membrane 130 can be reduced by the anti-interference layer 132, and then the interfering substance can be blocked outside the semipermeable membrane 130 by the diffusion control layer 131.

In some examples, in step S140, the order of step S141 and step S142 may be interchanged. That is, the diffusion control layer 131 may be first formed on the glucose oxidase or dehydrogenase layer (step S142), and then the anti-interference layer 132 may be formed on the diffusion control layer 131 (step S141). Thus, the interference of impurities to the working electrode 10 can be reduced, the inaccuracy of the detection result can be prevented, and the service life of the glucose monitoring probe 1 can be prolonged.

While the disclosure has been described in detail in connection with the drawings and embodiments, it should be understood that the foregoing description is not intended to limit the disclosure in any way. Modifications and variations of the present disclosure may be made as desired by those skilled in the art without departing from the true spirit and scope of the disclosure, and such modifications and variations fall within the scope of the disclosure.

Claims

1. A working electrode of a glucose monitoring probe for reducing interference is characterized in that,

comprises a basal layer, a sensing layer, a semipermeable membrane and a biocompatible membrane,

the base layer is arranged on the flexible substrate;

the sensing layer is formed on the basal layer by coating a sensing layer reagent, and can be subjected to chemical reaction with glucose in blood or tissue fluid, the sensing layer reagent comprises redox polymer, glucose enzyme, carbon nano tube and cross-linking agent, amino modification is added to the carbon nano tube so that the redox polymer and the carbon nano tube form covalent bond tightly and are combined with the glucose enzyme, the working voltage required by a working electrode is reduced under the catalysis of the carbon nano tube, and the glucose enzyme is glucose oxidase;

the semi-permeable membrane is formed on the sensing layer and used for controlling the passing rate of glucose molecules;

the biocompatible membrane is formed on the semipermeable membrane.

2. The working electrode of claim 1 wherein the electrode is,

in the sensing layer reagent, the mass fraction of the carbon nanotubes is 5% to 10%.

3. The working electrode of claim 1 wherein the electrode is,

The carbon nano tube is in a hollow column shape.

4. The working electrode of claim 1 wherein the electrode is,

the semipermeable membrane comprises a diffusion control layer for controlling the diffusion of glucose molecules and an anti-interference layer for blocking non-glucose substances.

5. The working electrode of claim 4 wherein the electrode is,

the anti-interference layer is formed on the sensing layer, and the diffusion control layer is formed on the anti-interference layer; or (b)

The diffusion control layer is formed on the sensing layer, and the anti-interference layer is formed on the diffusion control layer.

6. The working electrode of claim 4 wherein the electrode is,

the diffusion control layer reduces the magnification of the entering object by 10 to 100 times.

7. The working electrode of claim 1 wherein the electrode is,

the redox polymer has covalent, coordination or ionic bonds.

8. The working electrode of claim 1 wherein the electrode is,

the substrate layer is made of at least one selected from gold, glassy carbon, graphite, silver chloride, palladium, titanium and iridium.

9. The working electrode of claim 1 wherein the electrode is,

the sensing layer reagent further comprises graphene, porous titanium dioxide or a conductive organic salt.

10. The working electrode of claim 1 wherein the electrode is,

the thickness of the sensing layer is 2 μm to 10 μm.