JPH0472541B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for measuring blood glucose (blood sugar) concentration using glucose present on the surface of oral mucosa (buccal mucosa, hereinafter referred to as oral mucosa). More particularly, the present invention relates to a device for measuring blood glucose concentration using the peroxidative glucose oxidase enzyme.

[Prior art and problems to be solved by the invention]

In general, enzyme electrodes are often used to measure the concentration of substances in blood. A typical enzyme electrode combines enzymatic and polarographic techniques. Enzymes are usually physically or chemically bound to an inert support.

Many enzyme electrodes use enzymes that catalyze reactions that peroxidically oxidize substrates to produce hydrogen peroxide as a product. The specificity of an enzyme electrode is determined by the specificity of the enzyme to its substrate. Two types of analytical measurements are possible using polarographic techniques. More specifically, the amount of free oxygen consumed or the amount of hydrogen peroxide produced can be measured. Both serve as means of stoichiometric support for substrate oxidation. If the enzyme electrode is used after calibrating the enzyme electrode using a known concentration of the substrate, the enzyme electrode becomes a tool for quantitatively analyzing the unknown concentration of said substrate.

The peroxidation reaction with oxygen requires two types of substrates. That is, oxygen, which is usually present in excess, and an unknown substance on which the enzyme acts specifically and which is usually present in some limited amount are required. In operation, the enzyme is brought into an oxidized state before reacting with the substrate. After that, the enzyme and substrate are reacted, and then the enzyme is reduced. Reoxidation of this reduced enzyme produces hydrogen peroxide. If oxygen is not present, the enzyme's catalytic cycle cannot occur.

In view of the foregoing, it would be desirable to provide an enzyme electrode device for the analysis of glucose in animals or humans using the glucose oxidase enzyme. Such devices are extremely useful in diabetes treatment programs, ie, eliminating the need to take blood samples from diabetic patients for glucose (blood sugar) analysis.

In order to determine blood glucose concentrations for diagnostic and other purposes, the current state of the industry requires that a blood sample be taken from a patient. Blood samples are typically obtained from a patient by needle pricking a finger or by drawing a needle from a vein. However, these needle pricking methods are unsatisfactory because they damage the tissue or often cause discomfort to the patient.

Glucose oxidase-containing enzyme electrode devices have been previously constructed that were suitable for intravenous implantation. However, such electrode devices are not fully satisfactory since fibrotic tissue growth and immune system rejection prevent the device from functioning properly over long periods of time.

As an alternative to non-needle sampling methods, blood glucose concentration measurement at the surface of the body can be used, which is accomplished without blood sample collection.
Suitable body surfaces include skin and mucous membranes.

It is generally known that glucose diffuses from subcutaneous capillaries to the surface of hydrated skin. This consisted of an experiment consisting of placing a droplet of a buffer solution containing the enzyme and coenzyme used in the enzymatic analysis of glucose on the skin and measuring the increase in fluorescence when NADP was reduced to NADPH. It was shown by Importantly, dry skin is an effective barrier to the diffusion of hydrophilic molecules such as glucose, but this barrier is reduced by removing the stratum corneum and leaving only the dermis. However, the oral mucosa and dermis have nearly identical diffusion properties for many hydrophilic species, including glucose.

Therefore, an object of the present invention is to provide a blood glucose concentration measuring device that uses glucose present on the surface of the oral mucosa (buccal mucosa) of living things.

Another object of the present invention is to provide a device for measuring blood glucose concentration using peroxidative glucose oxidase enzyme.

Still another object of the present invention is to provide a blood glucose concentration measuring device based on a non-needle method.

Another object of the present invention is to provide an apparatus for measuring blood glucose concentration by supplying an excess amount of oxygen.

Still another object of the present invention is to provide a device for measuring blood glucose concentration using an electrode device.

Other objects of the invention will be partly apparent and will become apparent from the description below.

[Summary of the invention]

Generally speaking, the present invention provides a device for measuring blood glucose concentration that uses glucose present on the mucosal surface of living things. The device of the present invention is a device for measuring the blood glucose concentration of living things using glucose present in the oral mucosa (buccal mucosa) of living things, and includes a membrane device containing glucose oxidase enzyme for peroxidative oxidation of glucose; A membrane installation device in which the outer surface of the membrane device is placed in contact with the oral mucosal surface of a living creature; an oxygen supply device that supplies oxygen from atmospheric air to the membrane device through a passage placed in communication with the inside of the membrane device ; Contains both hydrogen peroxide produced by peroxidative oxidation of glucose in the coexistence of the oxygen supplied from the oxygen supply device and the glucose oxidase enzyme in the membrane device, and the oxygen supplied from the oxygen supply device. A blood glucose concentration measuring device comprising: a measuring device for measuring a change in the concentration of at least one compound selected from the group in the membrane device;

The present invention further provides a blood glucose concentration measuring device for living things that uses glucose present in the oral mucosa (buccal mucosa) of living things, the membrane device containing a glucose oxidase enzyme for peroxidative oxidation of glucose; A membrane installation device in which the outer surface of the device is placed in contact with the oral mucosal surface of a living creature; oxygen supplied to the inside of the membrane device by diffusing the membrane device from external atmospheric air, and the glucose oxidase enzyme in the membrane device. and hydrogen peroxide produced by peroxidative oxidation of glucose in the coexistence of the supplied oxygen. It will be equipped with
It also relates to a blood glucose concentration measuring device.

The measurement of blood glucose concentration using the device of the invention consists of an electrode supporting at one end a membrane containing glucose oxidase and in which the area of the membrane is supplied with oxygen from the atmosphere or from the air present in the opening containing the mucous membrane. This is achieved by using a device. The membrane is placed in contact with the surface of the mucous membrane of living things to initiate a peroxidative oxidation reaction. Next, the blood glucose concentration is determined by electrically measuring the amount of hydrogen peroxide produced during the peroxidative oxidation reaction using an electrode in communication with the membrane and comparing it with a calibration value.

In a preferred mode of use of the device of the invention, glucose concentration is measured at the oral mucosal surface.

Accordingly, the present invention comprises an apparatus comprising the structure, combination, and arrangement of elements and members suitable for performing a number of steps and a step of interrelating each step of the number of steps with the other steps; All of these are illustrated in the detailed disclosure below, with the scope of the invention being indicated in the claims.

In order to better understand the invention, the invention will be explained below with reference to the figures.

[Detailed description of preferred embodiments]

In order to measure the diffused glucose on the oral mucosal surface by peroxidative oxidation reaction, it is necessary to supply a sufficient amount of oxygen. However, the oxygen concentration found in the oral mucosa is usually insufficient to sustain peroxidative oxidation. According to the invention, this oxygen deficiency is overcome by arranging the elements in the electrode arrangement such that oxygen is transported to the membrane/electrode interface. Therefore, when the electrode device, which is the glucose measuring device of the present invention, is placed in an oxygen-deficient environment such as on the surface of the oral mucosa, an oxygen concentration gradient is formed, and this gradient feeds into the membrane covering the surface of the electrode, causing the oxygen to flow through the membrane. Penetrate.

Referring first to FIGS. 2 and 4, there is shown a membrane installation apparatus 11 according to the present invention. The membrane installation device 11 includes a handle 13, an electrode holding member 15 that is an electrode device member of the measuring device, and a cap member 17, and a membrane member 19 that is a membrane device.
is shown secured to cap member 17 by an O-ring 21.

The handle 13 of the membrane placement device 11 is substantially tube-shaped and includes a top member 41, a bottom member 33 and four sides 35a-35d. As shown in FIGS. 2 and 3, the handle 13 further includes a top member 4.
A protrusion member 37 is provided that extends in the lateral direction from the side surface 35c near the side surface 35c. During use of the membrane placement device, the protruding member 37 abuts the lingual surface of the user's teeth to firmly hold the membrane placement device 11 in place in the oral cavity.

The handle portion 13 also includes a side arm 23, which is a cylindrical housing, on the side surface 35a near the top member 41, which side arm 23 serves as an electrode holding member when the membrane placement device 11 is assembled, as best shown in FIG. Accept 15.

Referring again to FIGS. 2 and 4, the handle 13 also incorporates a longitudinally arranged electrode conductor wire passageway 25 of the electrode arrangement and an air passageway 27 (oxygen supply device). The electrode conductive line passageway 25 communicates with the outside through a conductive line opening 29 formed in the bottom member 33. The conductive wire passage 25 accommodates a large number of electrode conductive wires. In the preferred embodiment, as shown in FIG. 4, two (electrode) conductive wires 43 are shown, one of which is made of platinum [the tip acts as a cathode].
The other one is made of silver [the tip acts as an anode]. Each conductive wire 43 has conventional insulation 45 around it, but also includes insulation 46 within the conductive wire passageway 25 (which is preferably a Teflon shrink tube, but could also be an epoxy resin).

The air passage 27 communicates with the outside by means of an air opening 31 made on the bottom member 33. air passage 27
The other end of the handle 13 communicates with an air space 39 created under the top member 41 of the handle 13.

As best illustrated in FIGS. 2 and 4, the electrode holding member 15 of the membrane installation device 11 is removably housed in the side arm 23 of the handle 13, and is integrated with the insertion portion 51. It consists of a disk portion 49 formed in a central column portion 49 and a central columnar portion 47 extending from the disk portion 49 in a direction opposite to the insertion portion 51 . The column 47 has a top surface 48 and a cylindrical wall 50, both of which are preferably made of or coated with a non-wettable material such as Teflon. In order to easily accommodate and hold the electrode holding member 15 in the side arm, a peripheral protrusion 55 is formed on the insertion portion 51 of the electrode holding member 15, and this protrusion 55 is inserted along the inner surface of the side arm 23. Fittingly engages with the installed peripheral groove 53.

Electrode retaining member 15 is constructed with a centrally located orifice 57 for receiving electrode conductive wire 43 . This orifice 57 is connected to the columnar part 4.
7 through a column 47 including a top surface 48 . During assembly, the electrode conductive wire 43 is inserted into the wire opening 29 in the bottom member 33 of the winddle 13, through the conductive wire passageway 25 of the winddle 13 and the side arm 23, and into the orifice 57.

The electrode holding member 15 includes a number of air orifices 59 installed around its periphery. These orifices 59 extend through the insertion portion 51 of the electrode holding member 15 and the disc portion 49, but as best shown in FIG. exist. These air orifices 59 are preferably arranged in a semicircular manner as shown in FIG. This structure is advantageous because it allows for uniform diffusion of oxygen over the membrane surface when the electrode device of the invention is operatively placed on the oral mucosa of a living being. The air office 59 communicates with the air space 39 of the handle 13 so that air entering the air space 39 from the air passage 27 can flow through the air orifice 59.

As shown in FIGS. 2 and 4, the cap member 17 of the membrane installation device 11 includes a central opening 65, an annular surface 70, a peripheral groove 68 and a projecting annular lip 20.
Equipped with. The lip 20 includes a peripheral rib 22 which engages the rim of the disk portion 49 of the electrode holding member 15 when the cap member 17 is coupled to the electrode holding member 15. The opening 65 has an inner wall 66 which is preferably coated with or made of a non-wetting material such as Teflon. Fourth
As shown in the figure, the central columnar part 4 of the electrode holding member 15
7 is inserted into the central opening 65 of the cap member, and the cap member 17 and the electrode holding member 15 are fitted and connected.

Once the cap member 17 is attached to the electrode holding member 15
When coupled, an annular interior space 63 is formed between the members, which interior space 63 communicates with the air orifice 59 of the electrode holding member 15 . Furthermore, since the diameter of the (center) opening 65 is larger than the diameter of the (center) columnar section 47, the (center) columnar section 4
A peripheral air chamber 67 is formed around 7 , which air chamber 67 communicates with the interior space 63 . With this structure, air in the air space 39 passes through the air orifice 59 of the electrode holding member 15, and then passes through the internal space 63.
and finally enters the peripheral air chamber 67.

Referring now to FIG. 7, membrane member 19 is tensioned over cap member 17. This tension mounting positions the peripheral edge of the membrane member 19 along the peripheral groove 68 of the cap member 17, and then
- by mounting the ring 21 around the circumferential groove 68; Furthermore, since the columnar portion 47 protrudes to the outside of the cap member 17, the membrane member 19 is forced to have a slightly convex shape, and an annular water storage tank 69' is formed between the membrane member 19 and the cap member 17. . Since the membrane member 1 must be kept in a physiologically isotonic solution or in a storage solution when the electrode device of the invention is not in use, the water reservoir 69' is accessible to the user. When the electrode device is operatively placed on the oral mucosal surface, it becomes and remains filled with the solution. Therefore, the air that enters the electrode device through the various air passages mentioned above ends up in the water reservoir 6.
9' and comes into contact with the membrane member 19. the result,
Sufficient oxygen is supplied for the peroxidation reaction in the membrane member 19.

Referring again to FIGS. 4 and 7, the membrane member 1
9 is attached to the cap member 17, the top surface 48 of the columnar part 47 of the electrode holding member 15 is attached to the membrane member 19.
, so that the electrode conductive wire 43 contacts the inner surface of the membrane member 19 . Additionally, since the top surface 48 is curved, the membrane member 19
8 and is held tightly and smoothly.

Referring now to FIG. 5, membrane member 19 preferably consists of three layers: a protective outer layer 67', a central layer (glucose oxidase layer) 69, and an inner layer (membrane confinement layer) 71. Outer layer 67' extends along the entire surface of cap member 17 and is preferably made of cellulose. Outer layer 67' is the thickest and strongest of the three layers and thus helps stabilize membrane member 19. The outer layer 67' also excludes all substances with a molecular weight greater than 35,000, but is less resistant to molecules with a much lower molecular weight.

The central layer 69 is not coextensive with the outer layer 67', but extends only along the top surface 48 of the central columnar portion 47 of the electrode holding member 15. The central layer 69 comprises covalently immobilized glucose oxidase;
It can be made of any material with free reactive groups suitable for binding glucose oxidase molecules. Preferably, naturally occurring membrane materials with free _-NH2 groups are used, such as bovine mesentery (obtained from slaughterhouses or meat shops). To fabricate the central layer 69, the membrane material is first mixed with glucose oxidase and the coupling agent glutaraldehyde, which binds the glucose oxidase (enzyme) to the membrane and crosslinks the _-NH2 groups present in the membrane. Cultivate with. The resulting central layer 69 is thoroughly washed and then dried. The (middle) layer 69 is then rehydrated and used in the present invention.

The central layer 69 occupies the area at the tips of the (electrode) conductive wires 43 that covers the tip electrode portions of the conductive wires 43 . In a preferred embodiment, glucose diffuses from the oral mucosal surface through the outer membrane layer 67', while oxygen diffuses through the inner layer 71 (which is located between the central layer 69 and the central column 47 of the retaining member 15). diffuse through. Glucose oxidase catalyzes the following reaction: Glucose + O ₂ . . . H ₂ O ₂ + Gluconate Inner layer 71 is preferably made of a cast film of cellulose acetate. Inner layer 71 blocks the passage of molecules with a molecular weight of 100 or more. Hydrogen peroxide, a product of the reaction catalyzed by glucose oxidase, diffuses through the inner layer 71 of the membrane member and passes through the electrode conductive wire 4.
3, which is detected by the polarograph and produces a current proportional to the hydrogen peroxide concentration as a result of the following reaction: H ₂ O ₂ ...O ₂ +2H ⁺ + ^2e -Now, Figs. Turning now to FIG. 5, the electrode device 11 is operably installed in the oral cavity of a human user, as shown in the illustration of FIG. Cap member 17 with membrane member 19 placed thereon
onto the rinsed oral mucosal surface. As schematically shown in FIG. 5, glucose molecules G reach the membrane member 19 from the subcutaneous capillary 73 through the interstitial tissue 75 and the mucosal tissue 76 along a concentration gradient. The excess oxygen present in the area of membrane member 19 allows peroxidative oxidation reactions to occur with glucose as the limiting factor. The concentration of hydrogen peroxide produced therefore has a direct stoichiometric relationship to the concentration of glucose initially present.

The electrode conductive wire 43 passes through the electrode device to the membrane member 19.
and transport electrical signals when the electrode device 11 is operatively placed on the oral mucosal surface. More specifically, the presence of hydrogen peroxide, which is a peroxidation reaction product, is detected polarographically via the electrode conductive wire 43. This is accomplished by a platinum electrode conductive wire that detects the negative potential (electron transfer) generated by the reaction. The strength of the generated signal is proportional to the concentration of hydrogen peroxide produced, and the electrode conducting wire transports the electrical signal to an external device (reading means), which amplifies the signal and determines the concentration as a function of time. Display and record changes in Importantly, since the membrane member 19 is flexible, the membrane member 19 is attached to the top surface 48 of the columnar portion 47.
There is no gap between the top surface 48 and the membrane member 19 since the membrane member 19 is tightly bonded to the membrane member 19. Otherwise, the diffusion of hydrogen peroxide towards the electrode conductor line 43 is prevented.

Now, let's talk about Figure 6. 6 is a second embodiment of an electrode retaining member, generally designated 81, according to the present invention. The electrode holding member 81 includes a disk portion 79 and an insertion portion 8 integrally formed with the disk portion 79.
3, and further includes a columnar part 87, which protrudes to the side opposite to the insertion part 83. In this embodiment, a large number (for example, four) of electrode holding members 81 are arranged at equal intervals around the circumference.
orifice 85. This structure is advantageous because it allows oxygen to diffuse uniformly to the membrane surface.

Generally, the handle of the electrode device of the invention has the following functions: 1. Serves as a conduit for transporting air into the interior of the electrode holding member.

2 Contains an electrode conductive wire through which the electrode polarization effect is transmitted, and from the electrode an electric current of an amount comparable to the glucose concentration at the mucosal surface is sent to the amplifier and then to the display device. The electronic functionality may be built into the handle or placed in a separate device connected to the handle by conductive wires.

3. The handle stabilizes the electrode device when it is placed in contact with the oral mucosal surface. This stabilization is maintained by longitudinally extending projecting members on the top and bottom members of the handle, which projecting members are placed in close contact with the lingual edges of the teeth. This stabilization eliminates the generation of non-glucose-related signals that may be caused by physical movement of the electrode device after contact with the oral mucosa or by ingress of fluid. do.

The electrode holding member performs the following functions: 1. Allows oxygen to flow from the electrode housing into the space between the electrode holding member and the cap member.

2. Providing a watertight, insulated housing for connecting working electrodes and conductive wires, each used to detect hydrogen peroxide, a product of an enzymatic reaction.

The oxygen-transporting glucose electrode device according to the present invention is such that the amount of glucose measured at the oral mucosal surface is equal to the difference between the amount of glucose in the capillary and the amount of glucose absorbed by the cells during transport from the capillary to the oral mucosal surface. It produces a steady state signal that is the amount of glucose. At steady state, the glucose concentration at the oral mucosal surface is equal to the glucose concentration in the interstitial fluid bathing the cells. These signals can therefore be correlated with blood glucose under pre-prandial glucose tolerance test conditions and post-prandial glucose tolerance test conditions, in turn.

During operation, 5-10 minutes are required to obtain a signal related to steady state concentration of glucose. At this steady state concentration, glucose concentration equilibrium is achieved between the membrane and the oral mucosal surface. However, maintaining constant contact between the electrode surface and the mucosal surface for such a period of time is difficult and requires training. Therefore, since the relationship between the initial rate of an enzyme-catalyzed reaction and the concentration of substrate at a given temperature is well known, that relationship can be substituted into the steady-state analysis. Thus, the initial rate of change of the electrode signal is preferably used to indicate the oral glucose concentration.

The electrode device of the invention can be calibrated at room temperature (25° C.) using known glucose concentrations.

More specifically, when the electrode device of the present invention is operatively placed on an oral mucosal surface, the electrode surface is warmed by contact with the human body. Because the kinetics of reactions catalyzed by enzymes is temperature-dependent, temperature measurements both in vitro and in vivo (e.g., with a thermistor) can be used to construct and analyze calibration curves at known temperatures. )conduct. This allows the user to
Calibrate the electrode at any temperature within ~40°C (68〓~104〓) and then at other temperatures within this range, multiply the measured amperage by a constant to compensate for temperature effects on oral mucosal glucose. Concentration can be measured. The rate at which the electrode-membrane interface reaches temperature equilibrium after placing the electrode device on the oral mucosa can also be measured.

According to the invention, it is possible to generate an output signal that increases in proportion to the amount of glucose present in the mucous membrane. Both the rate at which the signal increases and the final steady state rate obtained are directly proportional to the concentration of glucose in the capillary.

As soon as the electrode device of the invention is applied to the oral mucosa, a concentration gradient of oxygen is created (this gradient spans concentrations between about 8.6 mM in air and about 0.2 mM at the interface). Oxygen is thus transported from the atmosphere to the membrane held in contact with the oral mucosal surface via the oxygen channels of the electrode device. That is, the electrode device uses the atmosphere as a reservoir for conducting oxygen necessary for the oxygen peroxidation reaction at the membrane-electrode interface.

The principles embodied in the present invention extend beyond the analysis of glucose to include the use of oxygen-requiring enzyme-electrode systems in oxygen-deficient environments.

After placing the membrane on the electrode, the electrode is calibrated by first placing the membrane in physiological buffer and then adding beta-D-glucose in portions. The amount of current from the electrode increases proportionally as the glucose concentration increases.

The presence of glucose on the oral mucosal surface is analyzed after each user first thoroughly washes his or her oral cavity with distilled water to remove glucose, including the glucose in the daphric fluid, from the oral surface. A wipe, such as a piece of gauze, is then used to wipe the membrane contacting surface to remove mucus residue and other contaminants. After a time interval of about 5 minutes when the membrane is brought into contact with the oral mucosa, the current increases to a plateau level.

Referring to FIGS. 8 and 9, a membrane installation apparatus 101 according to a second embodiment of the present invention is shown.
The membrane installation device 101 includes a handle 107, a stem 105 coupled to the handle, a base member 109 which is an electrode device (measuring device) member, and a base member 1.
It comprises an electrode member or probe member generally referred to as 102 supported by 09. Membrane placement device 101 also includes a protruding member 103 extending laterally from base member 109 and stem 105 . During use of the membrane placement device 101 in the user's mouth, as best shown in FIG.
3 between the user's upper molars 121 and lower molars 123 to securely hold the membrane placement device 101 in a predetermined position in the mouth.

Electrode conductor wire passageway 125 of the electrode device extends longitudinally through handle 107 and stem 105
The electrode conductive line passageway 125 communicates with the outside through an electrode conductive line opening (not shown) formed at one end of the handle 107. Electrode conductive wire 12
5 is housed in an electrical cable 112 containing a number of conductive wires 127. The conductive wire 127 is connected to the passage 125
and is capable of transporting electrical signals from an electrode device (measuring device) when the membrane placement device 101 is operatively placed on the oral (buccal) mucosal surface of a patient.

Turning the explanation to FIG. 10, the base member 109
The electrode member (probe) 102 supported by is shown in contact with the patient's oral mucosa 129.
The probe (electrode member) 102 includes a surface area 117 and a cathode 111 (preferably made of platinum) located in the center of the surface area 117 and slightly projecting therefrom. The probe also includes an anode 115 disposed substantially along the peripheral area of the surface area 117.
(preferably made of silver). Cathode 11
1 and the anode 115 are the probe (electrode member) 102
electrically connected to a conductive wire 127 (not shown) inside.

Membrane member 119 is tensioned over surface area 117 of electrode member (probe) 102 . This allows the peripheral edge of the membrane member 19 to be connected to the groove 10 on the peripheral edge of the electrode member 102.
4 and then the elastic O-ring 11
3 around the membrane member. Because the cathode 111 protrudes beyond the surface area 117 of the electrode member of the membrane member, the membrane member 119 assumes a slightly convex shape, as shown in FIGS.
An annular gap 128 is formed between membrane member 119 and surface area 117 as best illustrated in the figures. Furthermore, the annular anode 115 is also slightly attached to the membrane member 119.
It protrudes from the peripheral edge of and comes into contact with the membrane member 119.

As appropriate, the electrode member 102 is
- a reference electrode 120 installed under the ring 113;
may be provided. Reference electrode 120 is preferably made of platinum and has the feature of increasing electrical stability and is typically held at zero volts.

Figures 11 and 12 with reference to Figure 10.
Referring to the figures, membrane member 119 is operatively disposed on surface area 117 of electrode member 102 and abuts cathode 111 and anode 115. The membrane member 119 preferably has three layers: protective outer layer 1
35, middle layer (glucose oxidase content)
133 and an inner layer 131. Outer layer 135 extends along the entire surface of electrode member 102 and is made of polycarbonate. Inner layer 131 (which overlies cathode 111 and anode 115) consists of cellulose acetate. This cellulose acetate is permselective and allows H ₂ O ₂ to diffuse more easily than other materials with a molecular weight greater than H ₂ O ₂ .

The central layer 133 contains covalently immobilized glucose oxidase and, similar to the central layer 69 of the (first) embodiment described above, contains any suitable free reactive group for binding glucose oxidase molecules. It can be made from the following materials.

Membrane installation device 1 including electrode device members in the patient's oral cavity
01, the membrane member 119 consisting of three layers is saturated with an aqueous electrolyte solution or a buffer solution. The buffer solution then becomes saturated with atmospheric oxygen.
For best performance, the annular gap formed between the membrane member 119 and the electrode member surface area 117 is
128 is filled with buffer solution.

When the electrode device is placed in the patient's oral cavity, the central area of the membrane member contacts the oral mucosa 129, as shown in FIG. However, the peripheral area of membrane member 119 remains in communication with the air in the patient's oral cavity without contacting the oral mucosa. Due to the glucose oxidase reaction occurring in the area where the membrane member is in contact with the oral mucosa, the oxygen concentration in the buffer solution that was saturating the membrane member 119 is reduced. As a result, oxygen is directed from the air in the patient's oral cavity through the periphery of membrane member 119 to the central region of membrane member 119, as shown by arrow A in FIGS. 10 and 11.

As a result, an oxygen gradient is created in the membrane member 119, which ranges from the oxygen concentration in the (oxygen) saturated buffer solution at the periphery (approximately 0.21 mM) to the oxygen concentration at the oral mucosa (approximately 0.08 mM to 0.13 mM).
It can be characterized as the difference between This oxygen gradient provides a sufficient amount of oxygen to peroxidically oxidize all the glucose present in the oral mucosa, making it possible to produce hydrogen peroxide as a product.

In operation, an electrode conductive line 127 (which extends through the membrane placement device 101 and is electrically connected to the cathode 111 and anode 115 and the reference electrode 120) allows the electrode member 102 to be operatively connected to the oral mucosa. When located on a surface, they transport electrical signals. More specifically, the presence of hydrogen peroxide, a product of the peroxidative oxidation reaction, is detected by cathode 115 and anode 111, and electrode conductive wire 127
to an external device (reader) which amplifies the signal, displays it, and records the change in concentration as a function of time. The electrical detection of hydrogen peroxide is similar to the detection in the first embodiment of the electrode arrangement.

However, the membrane installation device 101 has certain advantages over the first embodiment. More specifically, the sensitivity is at least 5 times greater, the noise level is reduced by at least a factor of 10, and the signal/noise ratio is at least 50 times greater. This is due to the structural and functional changes described below.

(1) The electrode surface increased significantly.

(2) A third electrode surface, that is, a reference electrode is built-in.

(3) Oxygen was supplied to the mucosal surface from the air in the patient's mouth.

(4) Contains glucose oxidase in the central layer,
A unique three-layer structure that prevents various undesirable substances from diffusing to the anode surface.

(5) The stability of the position of the membrane and electrode relative to the oral mucosa was increased.

(6) The size and weight of the electrode device are reduced.

Although the method of the invention preferably includes the measurement of hydrogen peroxide to determine the glucose concentration,
Oxygen depletion may alternatively be measured to determine glucose concentration. This can be accomplished by reversing the polarity of the electrodes and measuring the decrease in current as molecular oxygen is reduced to hydrogen peroxide.

Although the method described herein measures blood glucose (blood glucose) concentration using glucose present in the oral mucosa, this method can also be applied to other mucosal surfaces such as the rectal, nitrous, and nasal surfaces of living things. blood sugar (glucose) using the glucose present in
It is also suitable for measuring methods.

Although the electrode device according to the invention does not include reading means, reading means for decoding the electrical signals carried by the conductive wires can be part of the electrode device.

The above-mentioned objects can be efficiently achieved from what is clear from the foregoing description, and modifications may be made in the implementation of the above-mentioned method and in the structure of the above-mentioned device without departing from the spirit and scope of the invention. That will be understood. All matter herein is intended to be illustrative and not in a limiting sense.

It is to be understood that the following claims encompass all generic and specific features of the invention as described herein.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram including partially shaded parts of the device of the present invention inserted into the oral cavity of a user, FIG. 2 is an exploded perspective view of the device according to the present invention used in FIG. 1, and FIG. A cross-sectional view taken along line 3--3 of FIG.
FIG. 4 is a cross-sectional view of the device shown in FIG. 1 to explain the oxygen path and electrode conductor path, FIG. 5 is an enlarged partial cross-sectional view showing details of the three-layer membrane and electrodes of the device shown in FIG. 7 is a perspective view showing another embodiment of the electrode support member of the membrane installation device, FIG. 7 is a perspective view showing the membrane coupled to the cap member of the membrane installation device, and FIG. 8 is another embodiment of the membrane installation device according to the present invention. A perspective view showing an aspect,
FIG. 9 is a partial cross-sectional side view of the membrane placement device of FIG. 8 held in place by the user's teeth placed in the user's oral cavity; FIG. 10 is a partial cross-sectional side view of the membrane placement device of FIG. Cross-sectional view taken along line 10-10 in the diagram showing the tip of the probe (electrode member), No. 11
10 is a front view taken along line 11--11 of FIG. 10, and FIG. 12 is an enlarged cross-sectional view taken along line 12--12 of FIG. 11. In the figure: 11...Membrane installation device, 13...Handle, 1
5... Electrode holding member, 17... Cap member, 19...
Membrane member, 20... (cap member) lip, 21...
O-ring, 22... (lip 20) peripheral rib, 2
3...Side arm, 25...(electrode) conductive wire passage,
27... Air passage, 29... Conductive wire opening, 31... Air opening, 33... (handle) bottom member, 35a
~35d...(handle) side surface, 37...protrusion member,
39...air space, 41...(handle) top member,
43... (electrode) conductive wire, 45, 46... insulating material, 4
7... (electrode holding member) (center) columnar part, 48...
(Central columnar part) surface, 49... (electrode holding member) disk part, 50... (center columnar part) cylindrical wall, 51... (electrode holding member) insertion part, 53... (side arm inner surface) peripheral groove, 55...(insertion part 51) peripheral protrusion part,
57... (electrode holding member 15) orifice, 59...
Air orifice, 63... (annular) internal space, 65
...(cap member) (center) opening, 66...(center opening) inner wall, 67...peripheral air chamber, 67'...(membrane member) outer layer, 68...peripheral groove, 69...(membrane member) central layer (glucose oxidase layer) ), 69'... (annular) water storage tank, 70... (cap member) annular surface, 7
1... (membrane member) inner layer (membrane-limiting layer), 73... subcutaneous capillary, 75... interstitial tissue, 76... mucosal tissue, 79... disc part, 81... electrode holding member, 83... insertion part, 85
... Orifice, 87 ... Column, 101 ... Membrane installation device, 102 ... Probe (electrode member), 103 ... Projection member, 105 ... Stem, 107 ... Handle, 10
9... Base member, 111... Anode, 113... O-ring, 115... Cathode, 117... (electrode member) surface area, 119... Membrane member, 120... Reference electrode, 12
1...Upper molar, 123...Lower molar, 124...Sulcus,
127...Electrode conductive wire, 128...Annular space, 129
...Oral mucosa, 131... (membrane member) inner layer, 133...
(Membrane member) Central layer, 135... (Membrane member) Outer layer, A
...Arrow direction, G...Glucose.

Claims (1)

[Scope of Claims] 1. A device for measuring the blood glucose concentration of living things using glucose present in the oral mucosa of living things, the membrane device containing glucose oxidase enzyme for peroxidative oxidation of glucose; an oxygen supply device that supplies oxygen from atmospheric air to the membrane device through a passage placed in communication with the inside of the membrane device; From the group containing both hydrogen peroxide produced by peroxidative oxidation of glucose in the coexistence of oxygen supplied from the oxygen supply device and glucose oxidase enzyme in the membrane device and oxygen supplied from the oxygen supply device A blood glucose concentration measuring device comprising: a measuring device for measuring a change in concentration of at least one selected compound in the membrane device. 2. The device according to claim 1, wherein the measuring device comprises an electrode device that generates a signal proportional to a change in the concentration of at least one compound selected from the group of supplied oxygen and produced hydrogen peroxide. 3. The device according to claim 2, wherein the electrode device comprises a conductive wire for transmitting a signal. 4. The device according to claim 2, wherein the electrode device includes an anode member and a cathode member. 5. The device according to claim 4, wherein the electrode device comprises an electrical grounding member. 6. The membrane device consists of an outer layer, a central layer and an inner layer,
2. The device according to claim 1, wherein the outer layer is a layer that comes into contact with the oral mucosal surface when the membrane device is placed in contact with the surface. 7. The device according to claim 6, wherein the outer layer is made of cellulose. 8. The device of claim 6, wherein the central layer comprises glucose oxidase enzyme. 9. The device according to claim 6, wherein the inner layer comprises cellulose acetate. 10 A patent in which the membrane installation device includes a handle member, an electrode device member comprising an electrode holding member coupled to the handle member, and a cap member coupled to the electrode holding member, and the membrane device is tension-fitted over the surface of the cap member. An apparatus according to claim 1. 11. The device of claim 10, wherein the handle member includes a laterally extending projection. 12. An oxygen supply device comprising: a first passage disposed in the handle member and communicating with the atmosphere; a second passage disposed in the electrode holding member communicating with the first passage; and a second passage disposed in the cap member and communicating with the atmosphere; 11. The apparatus of claim 10, further comprising a third passageway communicating with the inside of the apparatus. 13. The device according to claim 12, wherein the handle member includes a receiving member for removably receiving the electrode holding member. 14. The device of claim 13, wherein the receiving member comprises a side arm. 15. The device of claim 14, wherein the electrode holding member comprises a plug portion received in the side arm, a disk portion, and a central post extending from the disk portion to the opposite side of the plug portion. 16. The device according to claim 15, wherein the insertion portion includes a protrusion, and the side arm includes a groove into which the protrusion fits. 17. Claim 12, wherein the second passageway disposed in the electrode holding member comprises a number of air orifices.
Apparatus described in section. 18. The device of claim 15, wherein the cap member has a central opening, and when the cap member is assembled with the electrode holding member, the columnar portion of the electrode holding member projects through the central opening. 19. Claim 1, wherein the diameter of the central opening is larger than the diameter of the columnar part of the electrode holding member to form a chamber therebetween, and the third air passage is comprised of the chamber.
The device according to item 8. 20 a first conductive wire passageway having a handle member disposed therein and a second conductive wire passageway having an electrode holding member disposed therein;
11. The apparatus of claim 10, further comprising a conductive wire passage, and a conductive wire housed in the first and second conductive wire passages. 21. The device of claim 20, wherein the electrode holding member includes a column extending on the opposite side of the handle member when the electrode holding member is coupled to the handle member, and the second conductive wire passageway is provided within the column. 22. The device of claim 21, wherein the cap member has a central opening, and the columnar portion of the electrode holding member projects through the central opening when the cap member is coupled to the electrode holding member. 23 When the cap member is coupled to the electrode holding member, a columnar part of the electrode holding member projects from the cap member, and the columnar part has a surface area in contact with the membrane and a member that covers the cap member and tensions the membrane device. 22. The device of claim 21, comprising: a conductive line in contact with the membrane device at the surface area to transport an electrical signal. 24. The device of claim 23, wherein the membrane device is saturated with an electrolyte solution. 25. A device for measuring blood glucose concentration in living things using glucose present in the oral mucosa of living things, the membrane device containing glucose oxidase enzyme for peroxidative oxidation of glucose; A membrane installation device installed in contact with the oral mucosal surface; oxygen supplied to the inside of the membrane device by diffusing the membrane device from external atmospheric air, and the glucose oxidase enzyme in the membrane device and the supplied oxygen. A measuring device for measuring a concentration change in the membrane device of at least one compound selected from the group containing both hydrogen peroxide produced by peroxidative oxidation of glucose in the coexistence of blood; Glucose concentration measuring device. 26. The device of claim 25, wherein the measuring device comprises an electrode device for generating a signal proportional to a change in concentration of at least one compound selected from the group of supplied oxygen and produced hydrogen peroxide. 27. The device of claim 26, wherein the electrode device comprises a conductive wire for transmitting a signal. 28. The device of claim 26, wherein the electrode device comprises an anode member and a cathode member. 29. The device of claim 25, wherein the electrode device comprises an electrical grounding member. 30. The device according to claim 25, wherein the membrane device comprises an outer layer, a central layer, and an inner layer, and the outer layer is the layer that comes into contact with the oral mucosal surface when the membrane device is placed in contact with the oral mucosal surface. 31. The device of claim 30, wherein the outer layer comprises polycarbonate. 32. The device of claim 30, wherein the central layer comprises glucose oxidase enzyme. 33. The device of claim 30, wherein the inner layer comprises cellulose acetate. 34. The apparatus of claim 25, wherein the membrane placement device includes a handle coupled to the probe member, and the membrane device is tensioned over a surface area of the probe member. 35. The device of claim 34, wherein the membrane device is saturated with an electrolyte solution. 36. The membrane installation device comprises a handle member, a stem member coupled to the handle member, and an electrode device member including a base member coupled to the stem member and a probe member supported by the base member, 26. The device according to claim 25, which is arranged to cover the surface of the probe. 37. The device of claim 36, wherein the membrane placement device includes a projection member extending laterally from the probe member. 38. The device according to claim 36, wherein the probe member comprises an anode member and a cathode member. 39. The device of claim 38, wherein the cathode member is centrally located on the surface area of the probe member and projects from the probe member to contact the membrane device. 40. The device of claim 38, wherein the anode member is disposed along the peripheral area of the probe member.