JPH05223773A - Detection element - Google Patents

Abstract

PURPOSE:To obtain a wastable detection element detecting an inspected object included in blood and urine by making use of porous body fixing and holding biological catalyzer such as enzyme, and electrodes. CONSTITUTION:On a base tray 1, an electrode 2 and a porous reaction body layer 3 are provided and on the whole surface of porous support constituting the reaction body layer 3, a biological catalyzer which reacts with the inspected object and shows detectable change, is held. Thus the change due to the reaction with the inspected object in a sample coming in a sample inlet 5 can be sent from the electrode 2 through a joint 6 to an external reader device 11. As the sample quickly and uniformly diffuses, the contact efficiency between the inspected object and the biological catalyzer is high and exact and accurate measurement is possible in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can detect a test object contained in blood, urine or the like by utilizing a porous body carrying an immobilized biological catalyst such as an enzyme and an electrode. , External reader mating, disposable sensing element.

[0002]

2. Description of the Related Art There are various types of devices that allow ordinary people to easily measure blood glucose levels in a short time. For example, a simple blood glucose level measuring device comprising a blood sampling detector and a reading display is known. There is. In this device, a blood sampling instrument is pierced into the fingertip of a human or the like to cause a blood drop necessary for measurement to overflow to the fingertip, and the blood drop is directly collected from the fingertip from a sample collecting unit provided at the tip of the blood sampling detector, and the capillary phenomenon Is used to move the blood sample to the immobilized enzyme carrying part inside the blood sampling detector to allow the enzymatic reaction to proceed. Then, the amount of hydrogen peroxide generated is detected by the platinum electrode also inside the blood sampling detector. In this way, the signal detected by the blood sampling detector is sent to the reading display connected to the blood sampling detector, the blood glucose level in the blood sample is analyzed, and the result is displayed on the display panel. The blood sampling detector used for the test is contaminated with the blood sample and should be discarded, and the new blood sampling detector should be used for the next test.However, the reading indicator only receives an electrical signal, so it should be used continuously. it can.

In the above-mentioned blood glucose level measuring device, conventionally, as a detector, a printed circuit made of copper is formed on a substrate, and a part of this circuit is plated with platinum to form a platinum electrode, which is immobilized on the platinum electrode. An enzyme membrane was placed on top of which a hydrophilic porous body was placed as a blood retaining portion, which was used. That is, in this detector, the collected blood moves by a capillary phenomenon and is retained in the hydrophilic porous body, then permeates the immobilized enzyme membrane, and the sugar content in the blood reacts with the enzyme,
The amount of hydrogen peroxide generated at this time is detected by the platinum electrode. However, in this detector, since the sample such as blood passes through the porous body and the resin film before reaching the enzyme,
It takes time until the sample and the enzyme come into contact with each other, and moreover, the sample is difficult to be evenly distributed over the enzyme and the contact efficiency between the sample and the enzyme is poor, so that the measurement results are liable to vary. Also, among samples such as blood, it is only a part of the blood retained in the porous body that actually reacts with the enzyme,
There was also the problem that most of it wasted. Furthermore, in order to improve the detection accuracy, only hydrogen peroxide may be passed through the electrode surface to form a permselective membrane for eliminating substances that interfere with the detection. In such a type of detector, in such a case, the permselective membrane and the immobilized enzyme membrane must have a laminated structure,
Designing a laminated film so as not to affect the performance of the other has been an extremely difficult task requiring sophisticated technology.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to rapidly and uniformly move a sample to a supporting portion for the immobilized enzyme and to improve the contact efficiency between the sample and the immobilized enzyme. Accurately and highly accurately with a small amount of sample
Moreover, it is to provide a means capable of performing measurement in a short time.

[0005]

According to the present invention, the above object can be detected by an electrode by reacting with (1) a substrate, (2) a sampling port, and (3) a test object contained in the sample. A biological catalyst capable of causing a change is supported on the entire surface of the porous support, and a porous reactant layer provided on the surface of the substrate, (4) contacting the porous reactant layer,
An electrode capable of detecting a change due to a reaction between a test object contained in a sample and a biological catalyst, (5) a non-permeable cover covering a contact area between the porous reactant layer and the electrode,
And (6) a sensing element, characterized in that it comprises a reader joint having a terminal capable of sending a signal from the electrode to an external reader.

A representative embodiment of the sensing element according to the invention is shown in FIG.
2 and FIG. 2 (FIG. 1 is a sectional view taken along the line AA in FIG. 2).
The detection element 10 has a substrate 1, an electrode 2 formed on a partial region of one surface of the substrate 1, and a porous reactant layer 3 covering the entire electrode 2. The base 1 is made of an electrically insulating and moisture resistant sheet material. The electrode 2 can be provided on the substrate 1 by etching or plating a metal such as platinum on a printed circuit 7 made of copper or the like. At least one portion of the electrode 2 and the porous reactant layer 3 may be in contact with each other. The material of the porous support forming the porous reactant layer 3 is not particularly limited, but a fiber aggregate (for example, non-woven fabric, felt, woven fabric, knitted fabric) or foam or a composite thereof is preferable.
The non-woven fabric is particularly preferable because it has a three-dimensional structure.

The region where the porous reactant layer 3 contacts the electrode 2 is covered with a non-breathable cover 4. At one end of the base 1, a sampling port 5 made of the exposed porous reactant layer 3 not covered with the cover 4 is provided, and at the opposite end of the base 1, a joint 6 with an external reading device is provided. To provide. The joint portion 6 includes a pair of copper plate circuits 7, and the circuits 7 are in communication with the electrodes 2.
An exhaust port 8 is provided in the cover 4. The diameter of the exhaust port 8 may be small, and the position where the exhaust port 8 is provided is a position corresponding to the end of the porous reactant layer 3 on the side opposite to the sampling port 5. The cover 4 is preferably provided in close contact with the porous reactant layer 3 so as to keep the volume of the reactant layer constant.

The detection element of the present invention can be used for detecting and quantifying various biological test objects contained in an arbitrary sample, and in particular, a biological liquid sample such as blood, serum or plasma. Lipids (eg, cholesterol, phospholipids, triglycerides), sugars or nitrogen compounds (eg, urea, uric acid, creatinine), hormones (eg, growth hormone, luteinizing hormone, adrenocorticotropic hormone, insulin, etc.) It is used for detection and quantification of gastrin), various marker proteins (for example, tumor markers), and nitrogen compounds (for example, uric acid and urea nitrogen) contained in urine and the like. Prior to performing the test with the detection element of the present invention, the biological fluid sample can optionally be diluted with saline or the like, or treated with an agent such as an anticoagulant.

A biological catalyst is supported on the entire surface of the porous support constituting the porous reactant layer contained in the detection element of the present invention. Any biological catalyst may be used as long as it can react with a test substance contained in a sample to cause a change detectable by an electrode. For example, an enzyme, an antibody, an organelle, a microorganism or an animal or plant cell is used. You can In the present invention, the biological catalyst is selected according to the type of the test object. It is preferable to select a combination that finally produces hydrogen peroxide or ammonia by the reaction of the test object with one or more biological catalysts (particularly enzymes). Although many examples are already known as combinations thereof, typical examples are glucose-glucose oxidase (hydrogen peroxide), pyruvate-pyruvate oxidase (hydrogen peroxide), and urate-uricase (peroxidation). Hydrogen), urea-urease (ammonia), neutral fat-lipase and glycerol oxidase (hydrogen peroxide), cholesterol-cholesterol oxidase (hydrogen peroxide), L amino acid-L amino acid oxidase (hydrogen peroxide), ethanol-alcohol oxidase (Hydrogen peroxide), antibody protein-antibody and peroxidase. Further, the electrode is selected according to the type of the reaction product of the test object and the biological catalyst. For example, with respect to the hydrogen peroxide production reaction, the reaction can be detected by amperometry using a platinum electrode or a carbon electrode. Further, an ammonia electrode or an ion-selective field effect transistor (FET) electrode can be preferably used for the ammonia production reaction.

As a method for supporting the biological catalyst on the porous support, any method can be used.
For example, a carrier binding method in which a biological catalyst is directly or indirectly bound to the surface of a porous support by a covalent bond or an ionic bond (for example, the method described in JP-A-60-224618), silk fibroin, etc. Use the encapsulation method (the method described in JP-A-2-245189 or JP-A-60-120988) in which the biological catalyst is confined and immobilized in the lattice of the polymer gel or in the resin film. You can A method of attaching a biological catalyst to a porous support together with a surfactant and a stabilizer is also useful.

An example of the method of using the detecting element 10 according to the present invention will be described with reference to the mode shown in FIGS. 1 to 3. First, the fingertip 21 of the patient is injured with an appropriate needle-shaped projection to cause the blood 22 to overflow. Blood 22 is sampled by directly contacting the sample collection port 5 with the wound (FIG. 3). In FIG. 3, the detection element 10
The blood is collected with the external reading device 11 joined to the external reading device 11, but the reading device 11
You may make it join to. The shape of the sample collection port 5 and the like can be changed according to the type of sample, the collection method, and the like. For example, in the case of a blood sample, a needle-shaped projection is provided to make it possible to directly perform puncture collection, and in the case of a urine sample, an operation bar is attached to the detection element 10 to enable remote operation. You can also

The collected sample rapidly diffuses in the porous reaction material layer 3 made of a porous support by a capillary phenomenon, and the porous reaction material layer 3 is filled with a necessary amount. here,
When the non-air-permeable cover 4 is provided with the exhaust port 8, the replacement of the air occupying the space of the porous reactant layer 3 with the liquid sample is promoted. When the liquid sample contains test substances, they come into contact with the biological catalyst supported on the porous support, and the reaction between the two progresses, resulting in a detectable change (for example, reaction). Increase in product or decrease in reaction consumption) takes place. These changes are obtained by the electrode 2 as a change in potential or a change in current, and from the relationship between the potential or current previously obtained from the standard reagent and the reaction product or reaction consumer,
Measure the concentration of the test object. That is, the signal detected by the electrode 2 is conveyed from the circuit 7 to the joint portion 6, and the signal is further detected.
It is sent to the reading device 11 which is bonded to 0. The reading device 11 can analyze the signal and display the result by an appropriate means such as the display panel 12. Since the contact portion between the porous reactant layer 3 and the electrode 2 is covered with the non-permeable cover 4, when the electrode 2 measures the amount of gas generated, the gas does not dissipate and the gas generated is not generated. The amount can be detected accurately. A publicly known device can be used as the external reading device 11 which is joined to the detection element of the present invention to analyze and display the detection result. Detection element 10 used for inspection
Is contaminated with blood sample, it is taken out from the reader 11 and discarded, and a new detection element is used for the next test.
Used by joining to.

[0013]

As the porous reactant filled in the detection element according to the present invention is composed of the porous support, the sample diffuses rapidly and uniformly. Therefore, since the contact efficiency between the test object contained in the sample and the biological catalyst supported on the porous support is high, accurate, high-precision, and short-time measurement can be performed. You can

[Brief description of drawings]

1 is a cross-sectional view of one embodiment of the sensing element of the present invention.

FIG. 2 is a plan view showing a notch of a part of one aspect of a detection element of the present invention.

FIG. 3 is an explanatory diagram showing a state in which the detection element of the present invention is used by being joined to an external reading device.

[Explanation of symbols]

1 ... Substrate; 2 ... Electrode; 3 ... Porous reactant layer; 4 ...
・ Cover; 5 ・ ・ Sampling port; 6 ・ ・ Reading device joint part;
7 ... Circuit; 8 ... Exhaust port; 10 ... Detection element; 11 ...
・ Reading device; 12 ・ ・ Display panel; 21 ・ ・ Fingertips: 22 ・ ・
blood

Claims (1)

[Claims] 1. A substrate, (2) a sampling port, and (3)
A biocatalyst capable of reacting with a test object contained in a sample to cause a change detectable by an electrode is carried on the entire surface of a porous support, and the porous material provided on the surface of the substrate. Reactant layer, (4) An electrode that is in contact with the porous reactant layer and can detect a change due to a reaction between a test object contained in a sample and a biological catalyst, (5)
A non-breathable cover for covering the contact area between the porous reactant layer and the electrode; and (6) a reader joint portion having a terminal capable of sending a signal from the electrode to an external reader. Yes, the detection element.