JPH04194660A - Device for measuring concentration of component in blood - Google Patents

Abstract

PURPOSE:To simplify measuring preparation and to facilitate handling by integrating a measuring device main body and a puncture needle and providing an enzyme electrode in the cap body for the puncture needle. CONSTITUTION:A puncture needle 3 is provided to a measuring device main body 1 in a detachable manner and the cap body 2 for covering the puncture needle 3 is mounted on the main body 1 in a detachable manner. Further, the enzyme electrode 4 connected to the connector 14 of the main body 1 is provided to the cap body 2. When the concn. of the component in blood is measured, the end surface 2a of the cap body 2 is pressed to the surface of a fingertip in a close contact state and the first step of a plunger 13 set to two-step operation is pushed and the puncture needle 3 is allowed to protrude from the leading end of the cap body to discharge blood from the surface of the skin. This blood can be measured by the contact with the electrode provided to the inner surface of the cap body 2.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a measuring device that measures the concentration of components in blood using an enzyme electrode. This invention relates to a blood component concentration measuring device that can measure concentration.

(b) Conventional technology As a blood component concentration measuring device using a conventional enzyme electrode,
2. Description of the Related Art Clinical testing apparatuses having a configuration called a so-called discrete type or a flow type are known.

In these devices, sample dilution, measurement, device calibration, and cleaning are almost automated, or the devices are large and expensive and have high running costs. In addition, measurement takes a long time, requires a large amount of samples and buffer solutions, requires skill in handling the device, and is complicated to maintain and manage the device.

Therefore, in recent years, a device for measuring the concentration of blood components that can be easily measured as shown in FIG. 6 has been proposed.

This blood component concentration measuring device has a display 5 on a case body 51.
2 and an operation section 53, and a removable cartridge 54. An immobilized enzyme membrane 55 is supported on this cartridge 54 . By attaching the cartridge 54 to the case body 51, the enzyme membrane 55 is brought into close contact with a base electrode (not shown) exposed at the bottom of the cartridge 54, thereby forming an enzyme electrode.

The concentration of blood components is measured using a piercing needle called a lancet (
(not shown), prick the fingertip to draw a drop of venous blood, and drop this drop 56 onto the enzyme membrane 55. and,
After the enzyme electrode measures the concentration, the serum 56 is wiped off.

At this time, the standard solution (calibration solution) and buffer solution (cleaning solution) are also dropped and wiped off.

(c) Problems to be Solved by the Invention The blood component concentration measuring devices proposed in recent years as described above are small and inexpensive, and do not require maintenance.
It has the following problems.

■The measuring device itself and a lancet, which is separate from the main body, must be prepared together. In addition, blood must be collected with a lancet after the blood component concentration measuring device is set in a measurable state, making the operating procedure complicated.

■After blood is drawn with the lancent, when moving the finger to the measuring device, it is necessary to prevent the blood from falling.

In addition, careful handling is required, as one drop of blood must always be placed on the enzyme membrane.

■Measurement values vary depending on the position where the blood is dropped onto the enzyme membrane and the dropping speed. In addition, it is necessary to drop blood in an amount sufficient to fully fill the entire area of the enzyme membrane, and measurement requires careful discretion.

(2) Cleaning after measurement or calibration is complicated and time-consuming because the process of dropping a cleaning buffer onto the enzyme membrane and wiping it off is repeated. Furthermore, since the surface of the base electrode is directly touched and wiped off, the surface of the base electrode is easily scratched and damaged. vice versa,
If wiping is insufficient, droplets will remain on the enzyme membrane, which will adversely affect the next measurement. This results in so-called carryover, which deteriorates measurement accuracy.

■Since the base electrode and the enzyme membrane are separated, the degree of close contact between the base electrode and the enzyme membrane is reflected in the measurement results, leading to deterioration of measurement accuracy. Therefore, when attaching the enzyme membrane to the base electrode, the enzyme membrane is frequently damaged in an attempt to obtain a high degree of adhesion. Furthermore, the surface of the base electrode must be processed into a convex surface in order to improve its adhesion to the enzyme membrane, resulting in extremely high manufacturing costs. ■When replacing the enzyme membrane, complicated work such as dropping liquid onto the surface of the underlying electrode is required. Moreover, the amount of the dropped liquid affects the measurement results. Furthermore, after replacement, the electrode output is not stable for a while, and it takes time until measurement is possible.

(2) If the base electrode is damaged, there are many disadvantages such as the fact that it cannot be replaced because the base electrode is integrated with the case body.

This invention was made by focusing on the above-mentioned problems, and by integrating the measuring instrument body and a lancet (prick needle), and by disposing an enzyme electrode inside the cap body for the prick needle, measurement is possible. The purpose of the present invention is to provide a blood component concentration measuring device that is simple to prepare, easy to handle, has high measurement accuracy, and is inexpensive.

(d) Means and action for solving the problem In order to achieve this object, the blood component concentration measuring device of the present invention:
The structure is as follows.

A blood component concentration measuring device includes a measuring device main body, a puncture needle detachably attached to an appropriate position of the measuring device body, and a puncture needle detachably fitted to the measuring device body and covering the puncture needle. It is characterized by comprising a needle cap body and an enzyme electrode which is disposed inside the puncture needle cap body and whose connecting end drawn out to the outside is connected to the connector of the measuring instrument main body.

In a blood component concentration measuring device having such a configuration, a piercing needle is provided protruding from the tip of the round bar-shaped measuring device body. On the other hand, the puncture needle cap body is a cylindrical case that also serves as a micropipette tip, and a membrane-like enzyme electrode with a connecting end is arranged on the inner surface near the tip of this case (cap body). be.

The connecting end of this enzyme electrode is then inserted into the connector of the main body of the measuring instrument. The puncture needle can be projected outward from the tip side of the puncture needle cap body by a plunger of the measuring device main body. Therefore, when the fingertip is pricked in the protruding state, the blood from the fingertip adheres to the enzyme electrode on the inner surface of the pricking needle camp, and the blood component concentration is measured. In other words, in this measuring device, the puncture needle, the enzyme electrode, and the measuring device body are integrated. Therefore, preparation for measurement is simple, and measurement can be performed by operating a micropipette, making it easy to handle. Furthermore, since the finger with serum attached thereto is not moved, the blood sample can always be used for measurement. Furthermore, by operating the plunger on the measuring instrument, standard solution,
By supplying and discharging the cleaning buffer, the enzyme electrode is not touched during the wiping operation, and damage to the enzyme membrane and damage to the base electrode can be prevented. In addition, the enzyme electrode can be replaced by attaching and detaching the puncture needle camp.

(E) Embodiment FIG. 1 is a perspective view showing a specific embodiment of the blood component concentration measuring device according to the present invention.

The blood component concentration measuring device includes a measuring device main body 1, a puncture needle 3 removably attached to a proper position of the measuring device main body 1, and a puncture needle 3 that is removably fitted to the measuring device main body 1. 3
The cap body 2 for the puncture needle covers the cap body 2 for the puncture needle, and the enzyme electrode 4 is disposed inside the camp body 2 for the puncture needle and has a connection end connected to the connector 14 of the measuring device main body 1.

The measuring device main body 1 is formed into a round bar-shaped vent type, and is equipped with blood component determination means (means for determining the concentration of blood components by the output of the enzyme electrode), although not shown inside.
A display (liquid crystal display) It and an operation section 12 are provided at appropriate external locations. Further, a plunger 13 is provided at the rear end. Furthermore, as shown in FIG. 3, a connecting end 41a of an enzyme electrode 4, which will be described later, is inserted into the distal end side of the main body 1 of the measuring device, and a connector 14 is provided for connecting it to a quantitative means. be.

As shown in FIG. 3, the piercing needle (Lancet) 3 is
It is removably attached to the distal end of the measuring instrument body l via a holding part 15 in a protruding manner. This puncture needle 3 is inserted into the plunger 13 through a reciprocating means (not shown) such as a spring mechanism.
The needle cap body 2 is connected to the plunger 13, and is arranged so as to be able to protrude outward from the distal end side of the puncture needle cap body 2, which will be described later, by operating the plunger 13.

As shown in FIG. 2, the puncture needle cap body 2 is a case body that is removably fitted to the tip of the measuring instrument body 1.
It is a cylindrical case that can also be used as a micropipette tip. This puncture needle cap body 2 is open at both ends,
The front end side opening 22 serves as a hole for the puncture needle 3 to enter and exit. Furthermore, although not shown in the drawings, the plunger 13 includes:
The cylindrical case that is also the thousand knobs of this micropipette (
It is designed to have the function of supplying and discharging blood, standard solution, and washing buffer solution to the camp body) 2. In other words, the plunger 13, which comes and goes in two stages, is configured such that the puncture needle 3 protrudes in the first stage of the push operation, and the standard solution and washing buffer are supplied and discharged in the second stage of the push operation. (not shown).

As shown in FIGS. 4 and 5, the enzyme electrode 4 is placed at a suitable position on the inner surface of the puncture needle camp 2. The enzyme electrode 4 includes an electrode support substrate 41, a working electrode 42, a reference electrode 43 (the picture electrodes 42 and 43 constitute a base electrode), an insulating protective film 44, and an immobilized enzyme film 45. Become. The electrode support substrate 41 is made of an insulating material such as a plastic film, and the working electrode 42 is placed on this electrode support substrate 41.
, a control electrode 43 is formed. This base electrode is formed by forming a platinum film by applying means such as span ring, vacuum evaporation, and ion blating. Note that the electrode material for the base electrode is not limited to platinum,
The forming means can also be changed as appropriate, such as by attaching menki foil. Furthermore, an insulating protective film 44 is formed on this electrode support substrate 41 except for the connection end 41a, and a working electrode 42,
A reference electrode 43 is covered except for the sensitive parts 42b, 43b and the connecting parts 42a, 43a, respectively. Insulating protective film 44
uses a photosensitive polyimide resin and defines the sensitive area using photolithography. In addition, this insulating protective film 4
4, an immobilized enzyme membrane 45 is formed. This immobilized enzyme If! J45 is Nafion layer 45a1 enzyme layer 45
b. It has a three-layer structure in which Nafion layers 45C are laminated. Nafion is a product name of the American company DuPont, and its correct name is P.

1yperfluorosulfuric acid
It is a cation exchange polymer. This Nafion is commercially available as a 5% solution (the solvent is ethyl alcohol), and it is easy to form a film. In the examples, the film is formed by dip coating. The enzyme layer 45b is formed by dip coating with an enzyme solution. The enzyme solution was 0.1M phosphate buffer (pH 6.0), 10% glucose oxidase (COD), 7.5% bovine serum albumin (BSA), and 0.5% glitaraldehyde.
It was adjusted to have a concentration of . The enzyme electrode 4 having such a configuration is attached to the inner peripheral surface of the puncture needle camp body 2 with an adhesive or the like. At this time, the connection end 41a is exposed to the outside of the puncture needle cap body 2, and the working electrode 42 and the control electrode 43
The connecting ends 42a, 43a of the measuring device 1 can be connected to the connector 14 of the measuring device main body 1 (see FIG. 3).

When measuring the concentration of blood components with a blood component concentration measuring device having such a configuration, the puncture needle cap body 2
The measuring device main body 1 with the attached is pressed so that the end surface 2a of the puncture needle cap body 2 comes into close contact with the fingertip surface. Then, by pushing the first stage of the plunger 13, which is operated in two stages, the puncture needle 3 protrudes from the tip of the puncture needle cap body (opening hole 22) 2, causing bleeding on the skin surface. Measurement becomes possible when this blood comes into contact with the enzyme electrode 4 on the inner surface of the puncture needle cap body 2. When blood comes into contact with the enzyme membrane 45 of the enzyme electrode 4, the following reaction by the enzyme glucose oxidase (COD) occurs within the enzyme membrane 45.

At this time, the generated hydrogen peroxide (H20□) is oxidized in the perturbation portion 42b of the working electrode 42a, and this oxidation current becomes the electrode output. From this electrode output, the glucose concentration in the blood can be determined stoichiometrically. When the measurement is completed, the second stage of the plunger 13 is pushed to drain the blood, and the plunger 13 is operated to supply and drain the cleaning buffer, thereby cleaning the enzyme electrode 4. Furthermore, the puncture needle 3 is replaced by removing the puncture needle cap body 2 from the measuring device main body 1 (see Part 3).

In the above example, COD is immobilized as an enzyme to quantify the glucose concentration in the blood, but it is also possible to quantify the concentration of blood components other than glucose using other enzymes, and the design can be changed as appropriate. It is possible.

(F) Effects of the Invention Since the present invention has the above configuration, it has the following effects.

■Since a lancet and an enzyme electrode are provided together in one measuring device, preparation for measurement is simple, and measurement can be performed by operating a micropipette, making handling easy.

-Furthermore, since there is no need to move the finger with blood on it, the blood sample can always be used for measurement.

■Since the enzyme electrode is not touched during the wiping operation, there is no damage to the enzyme membrane and no damage to the base electrode.

■Enzyme electrodes have a simple structure, can be mass-produced, and can be provided at a low price, making them disposable.

■Since the washing buffer solution, etc. is discharged by the discharge operation of a micropipette, no droplets remain on the enzyme electrode. Therefore, carryover can be prevented and high measurement accuracy can be achieved.

■Since the enzyme membrane is integrally coated with the base electrode, the degree of adhesion between the enzyme membrane and the base electrode is constant, making it possible to perform measurements with excellent reproducibility.

■Also, there is no need to replace only the enzyme membrane, eliminating work that requires careful attention, such as wiping the underlying electrode.

■The enzyme electrode can be replaced by attaching and detaching the puncture needle camp, making it easy to replace.

■In addition to blood, only a small amount of washing buffer and standard solution are required, and no wiping tools are required, reducing running costs.

It has excellent effects such as

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example blood component concentration measuring device, FIG. 2 is a cross-sectional view of a puncture needle cap body of the example blood component concentration measuring device, and FIG. 3 is a perspective view showing an example blood component concentration measuring device. FIG. 4 is a longitudinal cross-sectional view of a main part showing the enzyme electrode of the blood component concentration measuring device according to the embodiment; FIG. 5 is a perspective view showing the component concentration measuring device with the needle cap removed; FIG. 6 is a cross-sectional view of a main part showing an enzyme electrode of a blood component concentration measuring device, and FIG. 6 is a perspective view showing a conventional blood component concentration measuring device. 1; Measuring instrument body, 2: Needle carrier, 7-piece body, 3:
Pierce needle, 4: Enzyme electrode, 14: Connector, 41a: Connection end. Patent applicant OMRON Co., Ltd. agent
Patent Attorney Shigeru Nakamura Figure 1/ Figure 2 Figure 4 Figure 6

Claims (1)

[Claims] (1) A measuring instrument main body, a puncture needle detachably attached to a suitable position on the measuring instrument main body, and a puncture needle cap body detachably fitted to the measuring instrument body and covering the puncture needle. and an enzyme electrode disposed inside the puncture needle cap body, the connecting end of which is pulled out to the outside and connected to the connector of the measuring device main body.