JP2002122562A - Biosensor for saliva - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that blood is required in order to determine a specific component in a living body with satisfactory accuracy and that the blood can be determined only by being accompanied by a pain. SOLUTION: The biosensor for saliva is manufactured in such a way that it is composed of a saliva introduction part, an electrode system composed of at least a determination electrode and a counter electrode, a saliva reaction part composed of an enzyme and an electron acceptor and a detection part which measures a reaction. A sugar concentration in the saliva is determined. Therefore, the sugar concentration which is related to a blood sugar value can be determined painlessly, in a short time and simply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting a specific component such as the concentration of sugar in saliva.

[0002]

2. Description of the Related Art With the advance of medical technology, by measuring specific components in blood and urine, it has become possible to check health, disease states, effects of treatment, and the like. However, conventionally, there has been a problem that it takes time and costs because the examination is performed by a large-sized machine or a complicated method in a clinical laboratory of a hospital. At present, diabetes is explosively increasing due to aging and high calorie diet, and a sensor that can be easily measured at home is desired.

[0003]

Attempts have been made to add a urine sugar sensor to the toilet and check it every day. This is effective for prevention, but the influence of meals is large and the fluctuations are severe. There is a problem. Furthermore, for those who control the sugar concentration by applying insulin, a simple blood sugar sensor is used under the guidance of a doctor. A small amount of blood is drawn by tapping a fingertip with an accessory needle, and a blood glucose level is measured by a glucose sensor to determine a dose of insulin. For this purpose, it is necessary to accurately measure the blood sugar level. However, the method of bleeding from the fingertips is painful, and the skin is damaged by repeated stroking, and is an intractable device for elderly people (particularly those who have diminished vision due to diabetes). Therefore, a sensor that can measure accurately and painlessly is desired.

[0004]

In order to achieve the above object, the present invention measures a saliva introduction part, an electrode system comprising at least a measurement electrode and a counter electrode, a saliva reaction part comprising an enzyme and an electron acceptor, and a reaction. By preparing a saliva biosensor comprising a detection unit and measuring the sugar concentration in saliva, the sugar concentration correlated with the blood sugar level can be measured easily and painlessly in a short time.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The biosensor of the present invention targets saliva as a biological sample. Saliva can be taken out painlessly and the burden on the subject is small. Therefore, as an embodiment of the present invention, a biosensor having a saliva introduction unit 1 is shown in FIG. Saliva is exuded from the secretory glands in the oral cavity, but saliva is most easily collected near the sublingual hill. Therefore, as shown in FIG. 1 or FIG. 2, the introduction part 1 in which the saliva introduction port 4 is open in a thin tubular shape 1 or a thin 2 mm thick 5 mm wide shape as shown in FIG. A voltage is applied to the reaction system 2 and the electrode system, which are composed of a layer of the enzyme glucose oxidase and the electron acceptor potassium ferricyanide that react, and an electrode system consisting of a measurement electrode and a counter electrode. And a display unit 3 for displaying the converted value. The saliva introduction unit 1 and the reaction unit 2 are configured to be inserted into the display unit 3 so as to be replaced each time measurement is performed. The display unit 3 includes a circuit for applying a voltage to the sensor, a circuit for measuring a current value flowing at that time, a circuit for converting the current value to a sugar concentration, a timer for measuring a reaction time, a panel including a liquid crystal or an LED for displaying the sugar concentration, and the like. Consists of

[0006] Glucose in saliva reacts with glucose oxidase and potassium ferricyanide to produce potassium ferrocyanide. When a current of 5 seconds after applying a +0.7 V pulse voltage with reference to the counter electrode is measured, an oxidation current corresponding to the concentration of the generated potassium ferrocyanide is obtained. When the linearity was examined using a glucose standard solution, it was possible to obtain up to 500 mg / dl. It has been reported that changes in salivary glucose concentration follow blood glucose levels. Thus, if the glucose concentration in saliva can be accurately measured, it can be applied to a person who is performing an insulin injection for controlling a blood sugar level, and the pain of collecting blood can be relieved.

(Embodiment 1) A measurement electrode 6 and a counter electrode 7 were formed on an insulating substrate 1 by screen printing (FIG. 3). Further, 10 mg of glucose oxidase was added to 1 cc of a 1% aqueous solution of carboxymethyl cellulose (CMC) and potassium ferricyanide 4 as an electron acceptor on the electrode.
0 mg of each was dissolved and applied, and dried at 80 degrees to form a reaction layer 9. The substrate 1 used polyethylene terephthalate. By making the thickness as thin as 100 microns, it is possible to finally form a cylindrical shape as shown in FIG. Alternatively, the inlet 4 is provided thereon with a thickness of 500 μm as shown in FIG.
To the substrate. Lecithin, a surfactant, was applied to the saliva introduction part and dried (8). Further, when introducing saliva, the air hole 10 penetrated to allow air to escape.
Was formed on the substrate or on the lid 11. Saliva was promptly supplied to the inlet 4 by lecithin, and the presence of the air holes 10 allowed the saliva to be smoothly introduced to the electrode portion. In addition to lecithin, nonionic surfactants such as polyoxyethylene sorbitan trioleate can be used. Since it is inserted into the mouth, a thing with high safety is good. Silver can be used as the electrode material, but if carbon is used, it can be manufactured at low cost. When the area of the reaction part was 4 mm square and the distance between the electrode part and the lid was 0.3 mm, the measurement was possible with a small amount of saliva of 5 μl. The secretion rate of saliva differs depending on the person, but a required amount of saliva could be collected in about 2 minutes at the maximum.

As shown in FIG. 5, before the saliva inlet 4,
When the fiber layer 13 made of cotton is added, saliva can be collected by capillary action from a wide range during saliva collection,
In addition, it also serves to filter viscous substances in saliva,
Measurement accuracy could be improved.

FIG. 6 shows the sensor oral cavity holder 14 provided with the sensor setting groove 15. The sensor is so thin that it is difficult to grasp and it is difficult to insert and hold it under the tongue up and down due to the weight of the display unit 3. Therefore, by adding the sensor intraoral holder 14 having a minimum width of 2 cm and being fixed by the upper and lower teeth, the sensor can be stably held during the measurement. Further, by providing the sensor setting groove 15 inside the sensor intraoral holding member 14, the sensor can be easily set on the sensor display unit without fail. The sensor is replaced every measurement, but the sensor oral cavity holder 14 is wiped with alcohol after the measurement. When used by individuals, the distance to the sublingual hill is constant, so if the position of the upper front tooth is noted on the sensor oral cavity holder 14, the sensor can be easily fixed at the same location.

A voltage is applied to the prepared measurement electrode 6 and the counter electrode 7, and when saliva invades, it is detected that the resistance between the two electrodes drops, and it can be detected that saliva has been introduced. After detecting the introduction of saliva, the reaction time is counted, and after 60 seconds, a pulse voltage of +0.7 V is applied by the circuit in the display unit 3 based on the counter electrode and the current after 5 seconds is measured. A good response with good reproducibility was obtained. In addition, if the patient is in pain while holding it to the mouth, a sound is emitted to notify the subject when the introduction of saliva is detected or after the reaction time elapses, so that it is not necessary to keep reading. The current value obtained by applying the pulse voltage is converted into a glucose concentration based on the calibration gland obtained with the glucose standard solution, and displayed on the display unit 3. In addition, since people suffering from diabetes often have poor eyes, it is difficult to read the display of the sugar concentration. Therefore, if the sugar concentration calculated by the display unit 3 is transmitted by voice, the device becomes very easy to use. Comparing the sugar concentration of the obtained saliva with the blood sugar level, the concentration in saliva is about 0.
The correlation was 01 times, and the fluctuation was well tracked. This proved that the measurement of the sugar concentration in saliva was effective.

The above sensor can be used not only for glucose but also for systems involving oxidoreductases such as alcohol sensors and cholesterol sensors. In addition to glucose oxidase, alcohol oxidase, cholesterol oxidase, complex enzymes and the like can be used as the oxidoreductase. The enzyme can be used after being immobilized with a crosslinking agent. Further, potassium ferricyanide reacts stably as an electron acceptor, which is suitable. However, if p-benzoquinone is used, the reaction speed is high, so that the reaction speed can be increased. Further, 2,2-dichlorophenol indophenol, methylene blue, phenazine methosulfate, β-naphthoquinone 4-potassium sulfonate and the like can also be used.

(Embodiment 2) In Embodiment 1, the method of electrochemically detecting an enzymatic reaction was used, but a method of optically detecting an enzyme reaction can also be used. The process of the reaction is described using glucose as an example. As shown in FIG. 7, a reaction layer 17 and a fiber layer 13 are laminated on a transparent substrate 16. The reaction layer 17 is formed by impregnating cellulose with glucose oxidase, peroxidase, and orthotoluidine. Gluconolactone and hydrogen peroxide are produced by glucose and glucose oxidase in saliva. Further, hydrogen peroxide generated by the catalytic action of peroxidase oxidizes ortho-toluidine and turns blue. The color-absorbed absorbance is measured by inputting light from below the transparent substrate 16 with an absorbance meter, and measuring the reflected light. The sugar concentration is calculated from the absorbance. When the measurement accuracy was measured using a glucose standard solution, it was 30 m from 0.3 mg / dl.
Linearity was obtained up to g / dl. Since saliva does not contain a large amount of pigment like blood, it can be measured accurately without disturbing the color reaction.

(Embodiment 3) As a method for measuring a trace amount of glucose with high sensitivity, a method utilizing fluorescence can be used to measure glucose in saliva which requires sensitivity 100 times higher than blood glucose. The reaction layer 17 is formed by impregnating cellulose with glucose oxidase, peroxidase, and homovanillic acid. Gluconolactone and hydrogen peroxide are produced by glucose and glucose oxidase in saliva. Further, hydrogen peroxide generated by the catalytic action of peroxidase oxidizes homovanillic acid and converts it into a fluorescent substance. By measuring this with a fluorometer (excitation wavelength: 315 nm, fluorescence wavelength: 425 nm), measurement corresponding to a glucose concentration as small as 0.02 mg / dl was possible. Even if p-hydroxyphenylacetic acid is used instead of homovanillic acid, it can be converted to a fluorescent substance.

[0014]

According to the present invention, a biosensor for saliva comprising a saliva introduction part, an electrode system comprising at least a measurement electrode and a counter electrode, a saliva reaction part comprising an enzyme and an electron acceptor, and a detection part for measuring a reaction is produced. By measuring the sugar concentration in saliva, the sugar concentration correlated with the blood sugar level can be easily measured in a short time without pain. In the reaction system, not limited to the electrode method,
Optical measurement methods can also be used. Not only the sugar concentration but also specific components such as lactic acid and alcohol can be measured simply by changing the enzyme system.

[Brief description of the drawings]

FIG. 1 shows a schematic configuration of a saliva biosensor.

FIG. 2 is a diagram showing a schematic configuration of a biosensor for saliva.

FIG. 3 shows a schematic configuration of a biosensor for saliva.

FIG. 4 is a diagram showing a schematic configuration of a biosensor for saliva.

FIG. 5 is a diagram showing a schematic configuration of a biosensor for saliva.

FIG. 6 is a diagram showing a schematic configuration of a biosensor for saliva.

FIG. 7 is a diagram showing a schematic configuration of a biosensor for saliva.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Saliva introduction part 2 Reaction part 3 Display part 4 Inlet 5 Substrate 6 Measurement electrode 7 Counter electrode 8 Surfactant layer 9, 17 Reaction layer 10 Air hole 11 Lid 12 Adhesive layer 13 Fiber layer 14 Sensor oral cavity holder 15 Sensor set Groove 16 Substrate

Claims (15)

[Claims] 1. A biosensor for saliva, comprising: a saliva introduction unit; an electrode system including at least a measurement electrode and a counter electrode; a saliva reaction unit including an enzyme and an electron acceptor; and a detection unit for measuring a reaction. 2. A method for measuring a specific component in saliva using a saliva introduction part, an electrode system comprising at least a measurement electrode and a counter electrode, a saliva reaction part comprising an enzyme and an electron acceptor, and a detection part for measuring a reaction. And measuring a change after the enzymatic reaction caused by the supply of saliva with the electrode system. 3. A saliva introduction unit, a saliva supply detection unit, an electrode system including at least a measurement electrode and a counter electrode, a saliva reaction unit including an enzyme and an electron acceptor, and a detection unit for measuring a reaction. Biosensor for saliva. 4. A saliva introduction unit, a saliva supply detection unit, an electrode system comprising at least a measurement electrode and a counter electrode, a saliva reaction unit comprising an enzyme and an electron acceptor, and a detection unit for measuring a reaction to detect a specific component in saliva. A method for measuring a specific component in saliva, wherein a change after the enzymatic reaction occurred during a certain period of time after the supply of saliva is detected in the saliva supply detection unit is measured by the electrode system. . 5. A saliva biosensor comprising a saliva introduction unit, a saliva reaction unit comprising an enzyme, an electron acceptor, and a color former, and an absorbance detection unit for measuring a reaction. 6. A method for measuring a specific component in saliva using a saliva introduction part, a saliva reaction part comprising an enzyme and an electron acceptor and a color former, and an optical detection part for measuring a reaction, wherein the enzyme reaction is performed by supplying saliva. A method for measuring a specific component in saliva, wherein the subsequent color development is measured by the optical system. 7. A saliva introduction unit, a saliva supply detection unit, an electrode system including at least a measurement electrode and a counter electrode, a saliva reaction unit including an enzyme and an electron acceptor, a detection unit for measuring a reaction, and a measurement end notification unit. A biosensor for saliva, characterized in that: 8. A sensor oral holding device, a saliva introduction unit, a saliva supply detection unit, an electrode system including at least a measurement electrode and a counter electrode, a saliva reaction unit including an enzyme and an electron acceptor, a detection unit for measuring a reaction, and measurement. A biosensor for saliva, comprising an end notification unit. 9. The saliva biosensor according to claim 1, wherein the saliva introducing portion has a cylindrical shape or a long axis shape having a space portion, and a surfactant is added to at least a tip portion. . 10. The saliva biosensor according to claim 1, wherein the saliva introducing portion has a cylindrical shape or a long axis shape having a space portion, and a surfactant is added to at least a tip portion. . 11. The saliva biotechnology according to claim 1, wherein the saliva introducing portion has a cylindrical shape or a long axis shape having a space portion, and a water-absorbing polymer is added to at least a tip portion. Sensor. 12. The biosensor for saliva according to claim 1, wherein the saliva introducing portion has a cylindrical shape or a long axis shape having a space portion, and a fiber layer is added at least at a tip portion. 13. The saliva biotechnology according to claim 1, wherein the saliva introducing portion has a cylindrical shape or a long axis shape having a space portion, and a water-absorbing polymer is added at least to a tip portion. Sensor. 14. A biosensor for saliva, comprising: a saliva introduction unit; a saliva reaction unit comprising an enzyme, an electron acceptor and a color former; and a fluorescence detection unit for measuring a reaction. 15. A method for measuring a specific component in saliva using a saliva introduction part, a saliva reaction part comprising an enzyme and an electron acceptor and a chromogen, and a fluorescence detection part for measuring a reaction, wherein the enzyme is supplied by saliva supply. A method for measuring a specific component in saliva, wherein the fluorescence after the reaction is measured by the optical system.