WO2012131903A1

WO2012131903A1 - Biosensor

Info

Publication number: WO2012131903A1
Application number: PCT/JP2011/057819
Authority: WO
Inventors: 武司上村; 希稲葉; 加成恵板岡; 悦夫篠原
Original assignee: 株式会社テクノメデイカ
Priority date: 2011-03-29
Filing date: 2011-03-29
Publication date: 2012-10-04
Also published as: JP5818275B2; JPWO2012131903A1

Abstract

[Problem] To provide a biosensor which allows the introduction of a specimen both from a fingertip and by dropping and can provide stable measurement results without being affected by a difference in specimen-introduction methods or a difference in specimen properties. [Solution] A biosensor, wherein a specimen channel allowing the introduction of a specimen by capillary action is formed between a substrate and an upper face plate, and an electrode, which is provided with a reaction layer containing an enzyme capable of reacting with a characteristic component in the specimen, is located in the specimen channel. The biosensor is characterized by comprising: a first specimen inlet having an opening at one end of the substrate and upper face plate and being connected to the specimen channel; a second specimen inlet being located in the upper face plate and connected at least to the area between the first specimen inlet and the electrode in the specimen channel; and a constricted part narrowing the width of the specimen channel, said constricted part being located between the first specimen inlet and the electrode in the specimen channel.

Description

Biosensor

The present invention relates to an improvement of a biosensor used for analyzing a specific component in a specimen.

Conventionally, disposable biosensors have been proposed for measuring specific components in a specimen, such as blood glucose level.
Specifically, in a conventional biosensor, for example, a sample such as blood is introduced from the sample introduction port, and the current value between the measurement electrode and the counter electrode when the introduced sample reacts in the reaction part is measured. In some cases, the value of the characteristic component in the specimen is measured.
Examples of the method for introducing the sample into the sensor include a method for introducing the sample into the sample introduction port of the sensor from the fingertip, a method for introducing the sample by dropping, and the like.
Specifically, for example, when the sample is blood, in the method of introducing from the fingertip, a small amount of blood is bleed from the fingertip by puncturing the fingertip, and the sampled blood is directly applied to the sample introduction port and the sample is used as a sensor. Introduce. When the bleeding fingertip is directly applied to the sample introduction port, if the sample introduction port is provided on the upper surface of the sensor, it is difficult to introduce the sample because the sample introduction port is hidden by the finger. For this reason, in the case of a sensor that introduces a sample from the fingertip, it is preferable that the sample introduction port is provided at the end of the sensor because blood is easily applied to the sample introduction port.
On the contrary, in the method of dropping the specimen from above, it is preferable that the specimen inlet is provided on the upper surface of the sensor.
Patent Document 1 shows a biosensor in which a sample introduction port is provided at the end of the sensor, and Patent Document 2 shows a biosensor in which a sample introduction port is provided on the upper surface of the sensor. .

JP 2002-168821 JP Special table 2001-516040

As described above, the location and structure of the sample introduction port differs depending on the method of introducing the sample, and the biosensor provided with the sample introduction port at the end of the sensor is suitable for introducing the sample from the fingertip. However, it is not suitable for introducing a sample by dripping, and conversely, a biosensor with a sample introduction port provided on the upper surface of the sensor is suitable for introducing a sample by dripping, but for introducing a sample from a fingertip. Is not suitable.
In view of the above-described conventional problems, the inventors have been researching a biosensor that can perform both the introduction of a specimen from a fingertip and the introduction of a specimen by dripping. And providing a sample inlet on both the sensor and the top surface of the sensor, the flow of the sample after sample introduction differs depending on whether it is introduced from the fingertip or dripping, so that stable measurement results can be obtained. There wasn't. Specifically, when a sample is dropped, a sufficient amount of sample can be introduced into the sensor in advance to collect blood in a syringe or the like. There are few variations in the way the sample flows in the sample flow path. In addition, in the case of introduction from the fingertip, the amount of sample is small, so the flow rate of the sample after sample introduction varies depending on the characteristics of the sample to be introduced (viscosity, hematocrit value, etc.). It was a cause of variation in measurement results.
The inventors have intensively studied to solve the above-described problems, and have invented the present invention.
The present invention can perform both the introduction of the specimen from the fingertip and the introduction of the specimen by dripping, and can provide a stable measurement result without being affected by the difference in the specimen introduction method and the specimen characteristics. It aims at providing the biosensor which can obtain.

In order to achieve the above-described object, the biosensor according to the present invention forms a sample channel into which a sample can be introduced by capillary action between the substrate and the top plate, and the sample channel includes a sample channel in the sample. In a biosensor comprising an electrode having a reaction layer containing an enzyme that reacts with a characteristic component, a first sample introduction port that opens at one end of the substrate and the top plate and communicates with the sample channel, and the top surface A second sample introduction port provided on the plate and communicating between at least the first sample introduction port and the electrode in the sample channel; and the first sample introduction port in the sample channel and the It is characterized in that a constriction part for narrowing the width of the specimen channel is provided between the electrode and the electrode.
Preferably, the second sample introduction port may be configured to form a part of the constricted portion.
Specifically, for example, the top plate is attached to a substrate via a double-sided tape made of an insulating material, and the double-sided tape is provided with a notch constituting the sample flow path, and one end of the notch An opening provided in the first sample introduction port may be configured to form the first sample introduction port. Further, in this case, the notch is formed with a convex portion projecting toward the sample channel, and a concave portion is formed at a position facing the convex portion, and at least at a position corresponding to the concave portion in the upper surface plate. An opening is formed so that a part thereof overlaps the sample flow path, and the second sample introduction port is formed by the recess of the notch and the opening of the upper surface plate, and the second sample introduction port and the notch The constricted portion may be formed with the convex portion.

The biosensor according to the present invention forms a sample flow channel into which a sample can be introduced by capillary action between the substrate and the top plate, and the sample flow channel contains an enzyme that reacts with a characteristic component in the sample. In the biosensor comprising the electrode having the reaction layer, the first sample introduction port that opens at one end of the substrate and the upper surface plate and communicates with the sample flow path is provided in the upper surface plate. A second sample introduction port communicating between at least the first sample introduction port and the electrode in the channel, and a sample channel between the first sample introduction port and the electrode in the sample channel Since the constriction part which narrows the width | variety of this is provided, both the introduction of the sample from a fingertip and the introduction of the sample by dripping can be performed.
In addition, when a small amount of blood that has been bleed from the fingertip by puncturing the fingertip is usually introduced from the sample introduction port provided at the tip of the sensor, the sample flow depends on which position of the sample introduction port the blood is in contact with. The way blood flows in the tract is different. The biosensor according to the present invention has a constricted portion that narrows the width of the sample channel between the first sample inlet and the electrode in the sample channel. Even if the sample is introduced, the sample always passes through the constricted portion, so that variation in the shape of the head of the blood when reaching the electrode is reduced. As a result, it is possible to obtain a stable measurement result while suppressing changes in the flow rate due to differences in the sample introduction method and differences in the characteristics of the sample.
In addition, by configuring the second sample introduction port to form a part of the constricted portion, compared to the case where the constricted portion and the second sample introduction port are separately formed, processing becomes easier. As a result, the price of the entire biosensor can be reduced.
Furthermore, the second sample introduction port is formed so as to form a part of the constricted portion, so that the length of the sample flow channel is longer than when the constricted portion and the second sample introduction port are separately formed. As a result, the overall size of the biosensor can be reduced, thereby reducing the required amount of specimen.

1 is a schematic top view of a biosensor according to the present invention. It is a schematic top view of the state which removed the upper surface plate of the biosensor shown in FIG. FIG. 2 is a development view of the biosensor shown in FIG. 1. (A)-(c) is a figure which shows the use condition of the biosensor which concerns on this invention, respectively.

Hereinafter, an embodiment of a biosensor according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic top view of a biosensor according to the present invention, FIG. 2 is a schematic top view of the biosensor shown in FIG. 1 with the top plate removed, and FIG. 3 is a biosensor shown in FIG. It is a general | schematic expanded perspective view of a sensor.
In the figure, reference numeral 1 denotes a substrate made of an insulator, and three

electrodes

2, 3 and 4 are formed on the substrate 1.
A reaction layer containing an enzyme that reacts with a specific component in the specimen is provided on the upper surface of the measurement portion 2a of the first electrode 2 and functions as a measurement electrode. Similarly, the second electrode 3 can function as a measurement electrode, and the third electrode 4 can function as a counter electrode.
In the drawing, reference numeral 3a denotes a measurement part of the second electrode 3, reference numeral 4a denotes a measurement part of the third electrode 4, reference numeral 2b denotes a terminal of the first electrode 2, and reference numeral 3b denotes a second electrode 3. Reference numerals 4b denote terminals of the third electrode 4, respectively.
A photoresist film 7 is provided on the substrate 1. The photoresist film 7 is formed shorter than the substrate 1 so as to cover portions other than the

measurement portions

2a, 3a and 4a and the

terminal portions

2b, 3b and 4b of the three

electrodes

2, 3 and 4, and the measurement portion 2a. , 3a, 4a,

openings

7a, 7b, 7c are formed.
Further, an upper surface plate 9 is provided on the upper surface of the photoresist film 7 via, for example, a polyethylene terephthalate (PET) double-sided tape 8. Here, the material is not limited to PET, and any plastic film having a certain rigidity may be used. For example, polyethylene naphthalate (PEN), polyethersulfone (PES), polyimide and the like can be mentioned.
The PET double-sided tape 8 is provided with a notch 8a to be formed. The PET double-sided tape 8 functions as a spacer for forming a gap between the photoresist film 7 and the top plate 9 that causes capillary action at the notch 8a.
The notch 8 a of the PET double-sided tape 8 surrounds the

measurement portions

2 a, 3 a, 4 a of the three

electrodes

2, 3, and 4 and constitutes the sample flow path 10.
The notch 8a is open at the end located on the opposite side of the

terminal portions

2b, 3b and 4b in the state of being arranged on the substrate 1, and this open end forms the first sample introduction port 11. .
Further, the notch 8a is disposed on the inner side (in the portion positioned between the open end (that is, the first sample introduction port 11) and the measurement portion 2a of the first electrode 2 in the state of being disposed on the substrate 1). That is, a convex portion 8b that protrudes to the specimen flow channel 10 side is formed, and a concave portion c that constitutes a second sample introduction port 12 described later is formed at a position facing the convex portion 8b.
The top plate 9 is formed with an air hole 9 a, an opening 9 b that constitutes the second sample introduction port 12, and a notch 9 c that forms the first sample introduction port 11.
Since the sample introduced into the sample flow channel 10 from the first sample introduction port 11 passes through the opening 9b (that is, the second sample introduction port 12) of the upper surface plate 9 due to the capillary phenomenon, the convexity of the notch 8a. A constricted portion between the first sample introduction port 11 and the measurement portion 2a of the first electrode 2 in the sample flow channel 10 by the portion 8b and the second sample introduction port 12 constituted by the recess 8c and the opening 9b. 13 will be formed.
The width of the first sample introduction port is 1.0 mm to 6.0 mm, preferably 2.5 mm to 3.5 mm. The height of the gap between the substrate and the top plate formed by the PET double-sided tape (8) is 0.05 mm to 0.5 mm, preferably 0.1 mm to 0.2 mm. This enables sample introduction by capillary action.
The width of the narrowest portion of the constricted portion is 0.05 mm to 3.0 mm, preferably 0.5 mm to 1.0 mm. Then, the flow rate of the sample introduced into the sample channel 10 from the first sample introduction port 11 is once rectified by the constricted portion 13 to stabilize the flow velocity, and due to the difference in sample characteristics (viscosity, hematocrit value, etc.). The difference in the shape of the blood head is converged.
Furthermore, the flow rate can be suppressed by controlling the hydrophilicity of the inner surface of the specimen channel (10).
Further, depending on the required blood collection amount, the introduction from the fingertip can be facilitated by providing the notch 9c on the upper surface.

4 (a) to 4 (c) are diagrams showing the usage state of the biosensor configured as described above.
FIG. 4A shows a state in which blood that has bleed from the fingertip by puncturing with the biosensor standing is introduced from the first sample introduction port 11 into the sample flow path 10. Shows a state in which blood that has bleed from the fingertip by puncturing while the biosensor is laid down is introduced from the second sample introduction port 12 into the sample flow path 10, and FIG. The state in which blood is introduced into the sample channel 10 by dropping the blood from the syringe from which the blood was collected into the second sample introduction port 12 in a state where the biosensor is laid down is shown.
As described above, according to the biosensor according to the present embodiment, it is possible to introduce the sample by both the method of introducing from the fingertip and the dropping method, and forming the constricted portion 13 in the sample channel 10. Since it is rate-limiting, the difference in flow velocity due to the difference in the amount and characteristics of the specimen (viscosity, hematocrit value, etc.) can be eliminated.
Furthermore, according to the biosensor according to the present embodiment, since the second sample introduction port 12 forms a part of the constricted portion 13, the constricted portion 13 and the second sample introduction port 12 are formed separately. In comparison, the length of the sample channel 10 can be shortened, and as a result, the overall size of the biosensor can be reduced, thereby reducing the required sample amount. Unlike venous and arterial blood, there are differences in the amount of bleeding among subjects when they are collected from the fingertips, and some subjects are significantly less. For such subjects, it is extremely painful to squeeze out blood. This structure brings about the result which reduces such a burden.
Further, as described above, the second sample introduction port 12 forms a part of the constricted portion 13, so that the constricted portion 13 and the second sample introduction port 12 are formed separately as compared with the case where the constricted portion 13 and the second sample introduction port 12 are formed separately. As a result, the price of the entire biosensor can be reduced. Since such a biosensor is disposable, it is very easy to manufacture and is inexpensive as described above.

In the above-described embodiment, the biosensor according to the present invention is described by taking the biosensor in which the three

electrodes

2, 3 and 4 are arranged in the sample channel 10 as an example. Of course, the arrangement, number and function of the electrodes are not limited to those of the present embodiment.

1 Substrate 2 First Electrode 2a Measurement Part 2b Terminal 3 Second Electrode 3a Measurement Part 3b Terminal 4 Third Electrode 4a Measurement Part 4b Terminal 7 Photoresist Film 7a Opening 7b Opening 7c Opening 8 PET Double-Sided Tape 8a Notch 8b Convex part 8c Concave part 9 Top plate 9a Air hole 9b Opening 9c Notch 10 Sample flow path 11 First sample introduction port 12 Second sample introduction port 13 Constricted part

Claims

An electrode having a reaction layer containing an enzyme that reacts with a characteristic component in the sample is formed between the substrate and the top plate by forming a sample channel capable of introducing the sample by capillary action. In the arranged biosensor,
A first sample introduction port that opens at one end of the substrate and the top plate and communicates with the sample channel;
A second sample introduction port provided in the upper surface plate and communicating between at least the first sample introduction port and the electrode in the sample channel;
In addition, a biosensor is characterized in that a narrow portion that narrows the width of the sample channel is provided between the first sample introduction port and the electrode in the sample channel.
The biosensor according to claim 1, wherein the second sample introduction port forms a part of the constricted portion.
The top plate is attached to the substrate via a double-sided tape made of an insulating material,
The double-sided tape is provided with a notch constituting the sample channel,
The biosensor according to claim 1 or 2, wherein an opening provided at one end of the notch forms the first sample introduction port.
Forming a convex portion projecting toward the specimen channel in the notch, and forming a concave portion at a position facing the convex portion;
An opening is formed at a position corresponding to the recess in the upper surface plate so that at least a portion thereof overlaps the sample channel, and the second sample introduction port is formed by the recess of the notch and the opening of the upper surface plate. ,
The biosensor according to claim 3, wherein the constricted portion is formed by the second sample introduction port and the notched convex portion.