JP2001305093A - Biosensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biosensor of good operability for a user with a clear supply part of a reagent solution. SOLUTION: This biosensor is provided with cavity structure 8 to allow sample liquid to be supplied by a capillary phenomenon to an electrode part comprising at least a measuring electrode 2 and a counter electrode 3 formed on an insulating substrate, and a reagent layer 5 formed on the electrode part. An inlet 9 of a cavity 8 formed at the side face of the biosensor is so formed that only the inlet part 9 portion of the cavity 8 is projected or recessed in a plane direction from the side face where the cavity 8 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biosensor for analyzing a specific component in a liquid sample, and more particularly, to a biosensor provided with a cavity for introducing a liquid sample by capillary action, in which the shape of the sensor can be easily supplied. And a cavity structure.

[0002]

2. Description of the Related Art Conventionally, various biosensors have been proposed as a system for simply quantifying a specific component in a sample solution without diluting or stirring the sample solution. As an example of such a biosensor, For example, Japanese Patent Application No. 11-3245
Sensors such as those proposed in No. 11 are known.

In this method, a measurement electrode, a counter electrode, and a detection electrode made of an electrically conductive substance are formed on an insulating substrate such as polyethylene terephthalate. In this case, a reagent layer containing an enzyme and the like that react with each other is formed.

[0004] Then, a certain amount of sample solution is collected, and a cavity for detecting the current value generated by the reaction between the specific component in the collected sample solution and the reagent layer is formed on the electrode. The spacer, whose part is elongated and cut away, and the cover in which the air holes are formed are attached to the insulating substrate.

In a biosensor having such a configuration,
The sample liquid is supplied into the cavity from the entrance of the cavity (sample liquid suction port) by capillary action, and is guided to a position where the electrode and the reagent are located. Then, a current value generated by a reaction between the specific component in the sample solution and the reagent on the electrode is read by connecting to an external measuring device through a lead.

[0006]

However, in the biosensor having the above-described configuration, the part for supplying the sample liquid is unclear and difficult to understand for the user, and the user is required to place the sample on the wrong part of the biosensor. There is a problem that measurement error or measurement error is induced by spotting the liquid.

[0007]

In order to solve the above-mentioned problems, the biosensor of the present invention has a configuration in which only the entrance portion of the cavity to which the sample solution is supplied is protruded from the side surface of the biosensor in the plane direction. By forming the concave portion, the sensor shape and the cavity structure in which the sample liquid supply site is clear are characterized, and an excellent biosensor with few measurement errors and measurement errors is provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to an electrode part comprising at least a measurement electrode and a counter electrode formed on an insulating substrate, and a cavity to which a sample solution can be supplied by capillary action. And a reagent layer formed in the cavity, wherein the entrance of the cavity formed on the side surface of the biosensor is formed so as to protrude or recess in the plane direction from the side surface. To provide an excellent biosensor with a small number of measurement errors and measurement errors, in which a sample liquid supply site is clarified and a user can easily recognize a sample liquid suction site. Can be.

According to a second aspect of the present invention, there is provided the biosensor, wherein the convex or concave region is in the form of an elongated strip on the side of the tip of the biosensor, and the side of the cavity in the longitudinal direction. The biosensor according to claim 1, wherein an entrance is formed, and by providing an entrance of the cavity on a side surface on which a user easily supplies the sample liquid, measurement error and a user operability are excellent. A biosensor with few measurement errors can be provided.

The invention according to claim 3 of the present invention is characterized in that the cavity is formed by bonding a cover having a notch for forming a capillary groove and a cover. Which embodies a cavity structure to which a sample liquid is supplied.

The invention according to claim 4 of the present invention is the biosensor according to claim 3, wherein the spacer is made of an opaque or translucent material, and the cover is made of a transparent material. The cavity part to be supplied is clarified, the user can easily recognize the sample liquid suction part, and an excellent biosensor with few measurement errors and measurement errors can be provided.

Furthermore, since the supply state of the sample liquid can be visually confirmed, it is possible to provide an excellent biosensor with less measurement errors and measurement errors due to insufficient sample liquid.

According to a fifth aspect of the present invention, there is provided the biosensor according to the first aspect, wherein an air hole is provided in the cavity to assist the supply of the sample liquid. By providing a hole for allowing the liquid to escape to the outside of the sensor, the supply of the sample liquid by the capillary phenomenon can be smoothly assisted.

The invention according to claim 6 of the present invention is characterized in that the shape of the air hole is any one of a circle, an ellipse, a triangle, a square, a rectangle, and a polygon. It is a sensor, which embodies the air hole shape of claim 5.

The invention according to claim 7 of the present invention is characterized in that the air hole is formed at the same position as the end of the reagent layer located farthest from the entrance of the cavity. It is possible to provide a high-precision biosensor which minimizes the diffusion of a reagent from the vicinity of an electrode after aspirating a sample liquid and minimizes measurement variation.

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIG. Here, an enzyme sensor using an enzyme as a molecular identification element that specifically reacts with a specific substance in a sample solution will be specifically described.

FIG. 1 is an exploded perspective view of a biosensor obtained by the present invention. On an insulating substrate 1, a measurement electrode 2, a counter electrode 3, and a detection electrode 4 made of an electrically conductive material are provided.
Are formed.

Note that the detection electrode 4 referred to here can function not only as an electrode for detecting a shortage of a sample amount but also as a part of a reference electrode or a counter electrode.

The preferred material for the insulating substrate is polyethylene terephthalate, polycarbonate, polyimide or the like. The preferred electrically conductive material is a noble metal such as gold, platinum or palladium, or a simple material such as carbon or carbon paste. A composite material such as a noble metal paste can be used. In the former case, the electrically conductive layer can be easily formed by a sputtering vapor deposition method, and in the latter case, a screen printing method or the like.

In forming the electrodes, the insulating substrate 1 is formed by a sputtering deposition method or a screen printing method.
After forming the electrically conductive substance on the entire surface or a part of the electrode, a slit can be provided by using laser trimming or the like, whereby the electrodes can be divided and formed. Further, the electrodes can be similarly formed by a screen printing method, a sputtering deposition method, or the like using a printing plate or a mask plate on which an electrode pattern is formed in advance.

On the electrode thus formed, a reagent layer 5 containing an enzyme, an electron carrier, a hydrophilic polymer, etc.
Are formed.

The enzymes include glucose oxidase, lactate oxidase, cholesterol oxidase, cholesterol esterase, uricase, ascorbate oxidase, bilirubin oxidase, glucose dehydrogenase, lactate dehydrogenase and the like. And its derivatives, phenazine methosulfate, methylene blue, ferrocene and its derivatives, and the like.

Examples of the hydrophilic polymer include polyamino acids such as carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, ethylhydroxyethylcellulose, carboxymethylethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone and polylysine, and polystyrene sulfone. Acid, gelatin and its derivatives, acrylic acid and its salts, methacrylic acid and its salts, starch and its derivatives, maleic anhydride and its salts, agarose gel and its derivatives, and the like can be used.

The reaction reagent layer containing these reagents is not only placed on the entire surface or a part of the electrode, but also in the cavity to which the sample liquid is supplied as long as the performance of the biosensor is not deteriorated. If so, it may be placed in any place.

Next, the cavity 6 to which the sample liquid is supplied is formed by laminating the cover 6 and the spacer 6 having the notch on the electrode and the reagent layer 5 thus formed. Suitable spacer and cover materials include polyethylene terephthalate, polycarbonate, polyimide, polybutylene terephthalate, polyamide, polyvinyl chloride, polyvinylidene chloride, polyimide, nylon, and the like.

Here, the biosensor of the present invention is significantly different from the conventional biosensor, in that only the entrance 9 of the cavity to which the sample solution is supplied is located in the convex region 10 provided on the side surface of the biosensor. It is located.

In the conventional biosensor not having the structure as in the present invention, the site for supplying the sample liquid (the entrance 9 of the cavity) arranged on the side surface of the sensor is difficult to understand. For a user who uses the sensor for the first time), there is a problem that a measurement error or a measurement error is likely to be induced, such as spotting blood on the air hole 11.

In order to solve such a problem, in the present invention, in order to clarify a portion to which the sample solution is supplied, a region having a convex shape which is partially projected from the side surface of the sensor is provided.
By arranging the cavity entrance 9 therein, it is possible for the user to clearly recognize the sample liquid suction site,
An excellent biosensor with few measurement errors and measurement errors can be provided.

Such an effect can be similarly obtained by using a concave shape in addition to the convex shape.

Further, the convex region 10 provided on the side surface of the sensor can be provided on any side surface as long as it can be measured. Is most preferably the side surface of the sensor tip.

When an opaque material or a translucent material is used for the spacer and a transparent material is used for the cover material to bond them together, only the cavity portion on the biosensor becomes transparent, and the sample liquid supply site is clearly defined. Therefore, it is possible to provide an excellent biosensor with few measurement mistakes and measurement errors without the user mistakenly supplying a sample liquid (for example, whole blood).

Further, since the cavity portion is transparent, the supply state of the sample liquid can be visually grasped, and an excellent biosensor with few measurement errors and measurement errors due to insufficient sample liquid can be provided. It becomes possible.

Examples of such an opaque material include a colored resin film in which the material itself contains a pigment as a coloring agent, and a material obtained by subjecting the surface of a transparent resin film to a color processing by gravure printing or dyeing. Can be used.

The supply of the sample liquid to the biosensor composed of such a cavity is realized by a capillary phenomenon. However, in order to realize a smooth supply of the sample liquid, air is discharged into the cavity to the outside of the sensor. Air hole 11 is required.

The arrangement of the air holes 11 may be at any position in the cavity as long as the supply of the sample solution is not hindered. However, when the air holes 11 are too far from the reagent layer, the diffusion of the reagent from the vicinity of the electrode causes the electrode to be diffused. Since the concentration of the reagent required above becomes low and the response value of the sensor tends to vary, the air hole is located at the same position as the rear part of the reagent layer (the reagent layer located farthest from the cavity entrance). It is more preferred that there be.

The shape of the air hole is a circle, an ellipse, a triangle,
Squares, rectangles, polygons, and the like can be used. In order to achieve a smooth supply of sample liquid, the same effect can be obtained using any shape, but the amount of sample liquid required to fill the cavity can be reduced, In order to further minimize the diffusion of the reagent, a square or a rectangle is more preferable.

In the biosensor formed as described above, the current value obtained by the reaction between the specific component in the sample solution and the reagent layer containing the enzyme and the like is measured by the leads of the measuring electrode, the counter electrode and the detecting electrode. The image data is read by connecting to an external measuring device (not shown) through 12, 13, and 14.

In the current measurement, in addition to the three-electrode system consisting of the measurement electrode, the counter electrode, and the detection electrode described in the present embodiment, there is a two-electrode system consisting only of the measurement electrode and the counter electrode. Any method may be used to achieve the effect described above, but the three-electrode method allows more accurate measurement.

Although the above description has been made with reference to the example of an enzyme sensor, a biosensor using an antibody, a microorganism, DNA, RNA or the like as well as an enzyme as a molecular identification element that specifically reacts with a specific substance in a sample solution is also described. It can be configured similarly.

[0040]

As described above, according to the present invention, the sample liquid supply site is clearly defined by arranging the entrance of the cavity to which the sample liquid is supplied in the convex or concave area provided on the side surface of the biosensor. In addition, it is possible to provide an excellent biosensor with few measurement errors and measurement errors.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a biosensor of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Insulating substrate 2 Measurement electrode 3 Counter electrode 4 Detection electrode 5 Reagent layer 6 Spacer 7 Cover 8 Cavity 9 Cavity entrance 10 Convex region 11 Air hole 12 Measurement electrode lead 13 Counter electrode lead 14 Detection electrode lead

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masaki Fujiwara 8 at Koshinmachi, Takamatsu-shi, Kagawa Prefecture Inside Matsushita Hisashi Denshi Kogyo Co., Ltd. (72) Inventor Nagariko Yamanishi 8 at Koshinmachi, Takamatsu-shi, Kagawa Prefecture Hisashi Matsushita Child Industry Co., Ltd.

Claims (7)

[Claims] 1. An electrode comprising at least a measurement electrode and a counter electrode formed on an insulating substrate, a cavity to which a sample solution can be supplied by capillary action, and a reagent layer formed in the cavity. In the biosensor, the entrance of the cavity formed on the side surface of the biosensor,
A biosensor characterized by being formed so as to protrude or depress in a plane direction from its side surface. 2. The biosensor according to claim 1, wherein the biosensor is in the shape of an elongated strip, and an entrance of the cavity is formed on a side surface of a tip end in a longitudinal direction. 3. The biosensor according to claim 1, wherein the cavity is formed by bonding a cover having a notch and a cover. 4. The method according to claim 3, wherein the spacer is made of an opaque or translucent material, and the cover is made of a transparent material.
A biosensor according to claim 1. 5. The biosensor according to claim 1, wherein an air hole for facilitating the introduction of the sample liquid is provided in the cavity. 6. The biosensor according to claim 5, wherein the shape of the air hole is any one of a circle, an ellipse, a triangle, a square, a rectangle, and a polygon. 7. The biosensor according to claim 5, wherein the air hole is formed at the same position as the end of the reagent layer located farthest from the entrance of the cavity.