JPH0519806Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention relates to a diffusion-limiting membrane attachment device in a biosensor. More specifically, this invention relates to a diffusion-limiting membrane attachment device for a biosensor. More specifically, it is a device for attaching a diffusion-limiting membrane to the surface of an enzyme electrode, which is replaced as necessary. The present invention relates to a diffusion-limiting membrane mounting device suitable for the purpose of installing a diffusion-limiting membrane.

<Conventional technology> Focusing on the characteristic of being able to selectively detect extremely complex organic compounds, proteins, etc. with extremely high sensitivity, bioactive substances are immobilized on the surface of electrodes. Research and development is being carried out to measure the above-mentioned organic compounds, proteins, etc. using enzyme electrodes.

When measuring a target substance using the enzyme electrode described above, it is usually necessary to oxidize the target substance.
Since the concentration of the substance to be measured is measured by carrying out reduction, etc. in the presence of the above-mentioned physiologically active substance and measuring the amount of produced substance or disappeared substance, the upper limit of the measurable concentration is the oxidation, This results in limitations depending on the amount of a substance that causes reduction, such as oxygen, to exist.

Focusing on this point, attempts have been made to increase the measurement limit concentration by attaching a diffusion-limiting membrane to the surface side of the immobilized enzyme membrane on which the physiologically active substance is immobilized, and by limiting the permeation rate of the substance to be measured. .

Specifically, a diffusion-limiting membrane is attached to a cap that is screwed to the base of a rod-shaped enzyme electrode, and when the cap is screwed in, the diffusion-limiting membrane is automatically brought into close contact with the immobilized enzyme membrane. There is.

By adopting such a configuration, the diffusion-limiting membrane can limit the permeation rate of the substance to be measured, making it possible to measure up to a considerably high concentration.

In addition, the diffusion-limiting membrane is made removable in order to eliminate the influence of interfering substances contained in the solution to be measured (for example, an increase in the diffusion-limiting effect due to adhesion of interfering substances) and to perform a good measurement. Therefore, a screw-in mechanism using a cap is adopted.

<Problems to be solved by the invention> When the diffusion-limiting membrane holder with the above structure is adopted, the diffusion-limiting membrane can be replaced relatively easily, but the mounting structure of the enzyme electrode base is In some cases, it becomes very difficult to put on and take off, and
Depending on the force applied during screwing, there is a problem in that uniform adhesion to the immobilized enzyme membrane may not be achieved. If such a problem occurs, measurement data will vary.

Furthermore, as the enzyme electrode base becomes smaller in diameter and the cap becomes smaller as a result, manual operations for replacing the diffusion limiting membrane become extremely difficult, making the above problems even more pronounced.

Furthermore, since the diffusion-limiting membrane is attached to the cap, there is a problem in that the space required for storage and transportation increases.

<Purpose of the invention> This invention was devised in view of the above-mentioned problems, and is capable of significantly simplifying the attachment/detachment operation of the diffusion-limiting membrane, and also ensures uniform adhesion to the immobilized enzyme membrane. It is an object of the present invention to provide a diffusion-limiting membrane mounting device that can perform the following steps.

<Means for solving the problem> In order to achieve the above object, the diffusion-limiting membrane attachment device of this invention consists of a pair of enzyme electrodes having an immobilized enzyme membrane on which a physiologically active substance is immobilized. A biosensor main body is provided with a positioning section, a flexible thin plate that contacts the biosensor in a curved state by being engaged with the pair of positioning sections, and an enzyme electrode of the flexible thin plate and a A diffusion-limiting film is fixed to a flexible thin plate in a state covering an opening formed at a location opposite to the diffusion-limiting film.

However, the above-mentioned pair of positioning parts may be immovably attached to the biosensor, or one positioning part may be immovably attached to the biosensor body, and the other positioning part can be moved up and down. may be attached to a biosensor.

Further, the flexible thin plate may be rotated while being engaged with one of the positioning parts, thereby being engaged with the other positioning part.

<Function> With the diffusion-limiting membrane mounting device configured as described above, the flexible thin plate to which the diffusion-limiting membrane is attached is attached to the pair of positioning parts provided with the enzyme electrode in between so as to cover the opening. By engaging, the flexible thin plate can be curved along the surface of the enzyme electrode, and as a result, the diffusion-limiting membrane can be brought into close contact with the surface of the enzyme electrode, and the opening can be aligned directly with the enzyme electrode. It is possible to set the state to

Therefore, if the analyte solution is dropped through the opening in this state, the diffusion of the analyte contained in the analyte solution into the immobilized enzyme membrane is restricted, which improves the measurement sensitivity when the analyte concentration is low. However, since saturation of the electrical output occurs later when the concentration of the substance to be measured is high, the measurable concentration limit can be increased.

If a measurement operation is performed using a solution to be measured that contains a substance with a particle size larger than that of the substance to be measured, the interfering substance with a large particle size may adhere to the diffusion-limiting membrane, causing the interference with the substance to be measured. Although the diffusion limiting effect would be too high, by disengaging the flexible thin plate from the pair of positioning parts, the diffusion limiting membrane can be removed integrally with the flexible thin plate.

Therefore, after that, by attaching a new flexible thin plate to the enzyme electrode again, it is possible to measure the substance to be measured without being affected by interfering substances.

If the above-mentioned pair of positioning parts are immovably attached to the biosensor, the diffusion-limiting membrane can be formed by curving the flexible thin plate along the enzyme electrode and engaging the other positioning part. can be installed.

In addition, when one positioning part is immovably attached to the biosensor body and the other positioning part is attached to the biosensor so that it can be raised and lowered, it is possible to can be engaged with a pair of positioning parts,
By lowering the other positioning part in this state, the flexible thin plate can be curved along the surface of the enzyme electrode, and the diffusion-limiting membrane can be brought into close contact with the surface of the enzyme electrode.

Furthermore, when the flexible thin plate is rotated while being engaged with one positioning part, it is also engaged with the other positioning part, and the flexible thin plate is engaged with the other positioning part at a time. The flexible thin plate can be attached accurately by simply performing the steps one after another. In this case, the aperture rotates around one of the engaged parts of the flexible thin plate, and a state in which it directly faces the enzyme electrode is generated during the rotation, so that the aperture and the enzyme electrode are can be easily and accurately positioned.

<Examples> Hereinafter, examples will be described in detail with reference to the accompanying drawings showing examples.

FIG. 2 is a plan view showing an embodiment of a flexible thin plate applied to the diffusion-limiting membrane installation device of this invention;
The figure is a longitudinal cross-sectional view, and shows a rectangular engagement recess 11 in the center of the long side of a substantially rectangular flexible thin plate 1 that is resistant to the solution to be measured and has a certain degree of flexibility. and one short side 12
is formed in an arc shape. A circular opening 13 centered at a position corresponding to the center of the short side 12
is formed. Further, a diffusion limiting film 2 is provided on the lower surface of the flexible thin plate 1 so as to cover the opening 13.
are attached by adhesive etc. Note that the other short side is used as the grip portion 14.

FIG. 4 is a plan view showing essential parts of an embodiment of the biosensor body applied to the diffusion-limiting membrane mounting device of this invention, and FIG. 5 is a longitudinal cross-sectional view. The enzyme electrode 4 is attached so that the mounting side of the immobilized enzyme membrane on which the physiologically active substance is immobilized protrudes upward, and the enzyme electrode 4
Positioning portions 5 and 6 are provided at opposing positions with the two sides in between. To explain in more detail, the positioning section 5
has an engagement recess 51 whose inner deep part is formed in an arcuate surface having the same radius of curvature as the short side 12, and a protrusion forming an upper regulating protrusion of the engagement recess 51. 52, and further includes a rotation prevention portion 51a at a predetermined position on the end side of the engagement recess 51 to prevent rotation of the flexible thin plate 1. The protrusion 52 may be wide enough to cover the entire width of the engagement recess 51, or may be narrower than the entire width of the engagement recess 51. Further, the positioning portion 6 has an upright portion 61 having a width approximately equal to the width of the engaging recess 11, and an upper regulating protrusion 62 extending in one direction from the upper portion of the upright portion 61. Note that the surface of the enzyme electrode 4 is formed into a substantially arc-shaped surface. The upright portion 61 may have a rectangular cross-sectional shape,
It is preferable that the cross-sectional shape is tapered to facilitate engagement with the engagement recess 11.

When attaching a diffusion restriction membrane to the biosensor main body 3 having the above configuration, insert the short side 12 of the flexible thin plate 1 into the engagement recess 51 with the diffusion restriction membrane 2 positioned on the bottom surface. (However, in this state,
(The positional relationship between the center of the opening 13 and the center of the enzyme electrode 4 is shifted as shown in FIG. 1A), then,
With the flexible thin plate 1 forcibly curved so that the diffusion-limiting membrane 2 is in close contact with the surface of the enzyme electrode 4, the flexible thin plate 1 is moved in the direction in which the engagement recess 11 engages with the positioning part 6. By rotating the upper restricting protrusion 62 of the positioning part 6 so that the flexible thin plate 1 is prevented from restoring (see FIG. 1B), the diffusion limiting membrane 2 is aligned with respect to the enzyme electrode 4. It is possible to maintain an accurate relative positional relationship and to maintain close contact.

Therefore, in this state, as shown in FIG. . The diffusion of the substance to be measured is restricted by the diffusion-limiting membrane 2, and the substance to be measured is guided to the enzyme electrode 4 with its concentration reduced to a certain degree. As a result of this limitation, the concentration of the substance to be measured can be measured based on a considerably low concentration of the substance to be measured.

Further, after the measurement is completed, the flexible thin plate 1 can be easily removed by operating the flexible thin plate 1 in the opposite manner to the above-mentioned mounting operation. In other words, if a measurement is performed using a solution to be measured that contains an interfering substance with a particle size larger than that of the target substance, if the next measurement is carried out as is (but with the refresh performed), Since measurement errors occur due to the influence of interfering substances, the diffusion limiting membrane 2 is removed together with the flexible thin plate 1 as described above, and replaced with a new diffusion limiting membrane 2 that is not affected by interfering substances. can do.

Furthermore, in the above embodiment, the flexible thin plate 1 may be subjected to hydrophilic treatment in a portion close to the opening 13, and in this case, the dripped measurement target solution 9 is smoothly guided to the opening 13. be able to.

As is clear from the above explanation, the replacement diffusion-limiting membrane 2 is attached to the flexible thin plate 1, and the overall thickness is quite thin, so a large number of membranes are laminated. However, it can be made low in bulk and can be stored and transported reliably in a small amount of space.

FIG. 6 is a plan view showing another embodiment, and the only difference from the above embodiment is that the shape of the opening 13 is made into a shape having many unevenness, and the configuration of other parts is the same. .

Therefore, in the case of this embodiment, the measurement target solution 9 can be smoothly guided to the opening 13 even if no hydrophilic treatment is performed. It goes without saying that if hydrophilic treatment is applied, the solution to be measured can be guided to the opening 13 even more smoothly.

FIG. 7 is a plan view showing still another embodiment, which differs from the above embodiment only in that a plurality of grooves 41 are formed around the opening 13, and the configuration of other parts is the same. It is.

Therefore, also in the case of this embodiment, the measurement target solution 9 can be smoothly guided to the opening 13 even without being subjected to hydrophilic treatment.

However, the shape of the groove 41 need not be linear as shown in FIG. 7, but may be spiral as shown in FIG.

FIG. 9 is a schematic diagram showing another embodiment of the biosensor main body 3, and the only difference from the above embodiment is that the positioning section 6 can be moved up and down.

To explain in more detail, the biosensor main body 3
a state selection member 6 that is attached to the member and selects between a protruding state and a pushed-in state each time a pressing force is applied;
3 and a follower member 64 that is moved up and down following the state selection member 63, the positioning section 6 is configured.

The state selection member 63 is biased by a spring (not shown) in a direction opposite to the direction of the pressing force, and a cam mechanism (not shown) maintains the pressed state and releases the pressed state when the pressing force is applied. It has a conventionally known configuration in which it is sequentially selected each time it is applied, and a connecting portion 63a that connects the follower member 64 is formed at a predetermined position.

The following member 64 has one end connected to the connecting portion 63a.
An upright portion 64 is provided at the other end of the arm portion 64a that is connected to the arm portion 64a.
b is integrally provided, and a groove 64c into which the flexible thin plate 1 is inserted is formed at a predetermined position of the upright portion 64b, and the maximum width of the remaining portion following the groove 64c is the engagement recess 1.
It is set to a predetermined width that is not greater than 1.

Therefore, in the case of this embodiment, by applying a pressing force to the state selection member 63 while the flexible thin plate 1 is engaged with one of the positioning parts 5 and the above-mentioned following member 64, the following is achieved. The member 64 is lowered and held in the lowered state, and the flexible thin plate 1
The diffusion-limiting membrane 2 can be brought into close contact with the enzyme electrode 4 by curving the membrane.

On the other hand, when removing the diffusion-limiting membrane 2, a pressing force is applied to the state selection member 63 to release the lowering state of the follower member 64, thereby changing the state of close contact between the diffusion-limiting membrane 2 and the enzyme electrode 4. It is only necessary to remove the flexible thin plate 1, and the flexible thin plate 1 can be easily removed.

In the embodiment shown in FIG. 9, the position of the state selection member 63 and the upright portion 64b are different, but if both can be provided at the same position, the arm portion 64a may be omitted. , the state selection member 63 and the following member 64 can be integrated. Further, the configuration of the above-mentioned upright portion is not limited to the configuration shown in the embodiment of FIG. 9, and for example,
As shown in FIG. 10, holding portions 64d are formed to slidably hold both long sides of the flexible thin plate 1, which does not have any engagement recesses 11 formed therein. In addition to being able to perform the setting by sliding operation, as shown in Fig. 11,
The holding parts 64e that slidably hold both long sides of the flexible thin plate 1 are configured to be able to come into contact with and separate from each other, and the holding parts 64e
A rotation forcing part 64f is provided to forcibly rotate the holding parts 64e in a direction in which they approach each other, and the holding parts follow the downward movement of the holding part 64e and rotate in a direction in which the holding parts approach each other. It is possible to horizontally position the flexible thin plate 1 and to hold it in the positioned state (see FIG. 11B).

Furthermore, the portion to which the short side is engaged is not limited to the engagement recess 51 and the protrusion 52 as described above, but for example, as shown in FIG. Alternatively, the flexible thin plate 1 may be constructed with only the slit 53, and the flexible thin plate 1 can be attached and detached with a simple operation as in the above embodiment.

Furthermore, the structure of the flexible thin plate 1 is not limited to the above embodiment; for example, the strength can be improved by bending the gripping portion side into a chevron shape, and the structure shown in FIG. As shown in A, B, and C, only the gripping portion side of the flexible thin plate 1 is formed narrow, and a notch 31 for positioning is formed in the wide end side 12 (see A in the same figure). ), or a positioning protrusion 32 may be formed (see Figure C), and as shown in Figure 14A, the wide side is circular and at least one positioning protrusion 32 is formed at a predetermined position on the circumference. A cutout recess 31 may be formed for the purpose, as shown in FIG.
As shown in FIG. Predetermined positions on one short side and one long side of the flexible thin plate 1, where the width is not very large, may be used as the engagement portions for positioning.

However, when employing the flexible thin plate 1 having the above structure, a protrusion that engages with the notch recess or hole may be formed at a predetermined position of the positioning portion 5, or Accurate positioning may be achieved by forming engaging recesses. The attachment of one end of the flexible thin plate 1 may be done by inserting it from any direction.
Alternatively, a guide groove or the like may be provided, and the slide may be performed in a horizontal direction along the guide groove.Furthermore, a guide protrusion may be provided that extends in the vertical direction, and the guide protrusion may be slid along the guide groove. It may also be by sliding downwardly along the line.

<Effects of the invention> As described above, this invention has a diffusion-limiting membrane integrally attached to a flexible thin plate that is long in one direction and has an opening for permeation of the solution to be measured.
Since a pair of positioning parts are provided with the enzyme electrode sandwiched between them, the diffusion-limiting membrane can not only be easily attached and removed by simply engaging the flexible thin plate with the positioning parts, but also can be easily attached and removed during installation. This has the unique practical effect of being able to reliably maintain the close contact state.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating the operation of attaching a diffusion-limiting membrane according to this invention, FIG. 2 is a plan view showing an embodiment of a flexible thin plate applied to the diffusion-limiting membrane attaching device according to this invention, and FIG. 4 is a plan view showing essential parts of an embodiment of the biosensor body applied to the diffusion-limiting membrane mounting device of this invention, FIG. 5 is a longitudinal sectional view, and FIGS. 9 is a plan view showing another embodiment of the flexible thin plate, FIG.
and FIG. 11 are a schematic diagram of main parts and a first embodiment showing still another embodiment of the diffusion-limiting membrane mounting device, respectively.
FIG. 2 is a schematic perspective view showing another configuration of the main part of the biosensor, and FIGS. 13 and 14 are plan views showing still other embodiments of the flexible thin plate. 1...flexible thin plate, 2...diffusion-limiting membrane, 3...
Biosensor body, 4... Enzyme electrode, 5, 6...
Positioning part, 11... Engagement recess, 12... Short side,
13...Opening.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A biosensor body having a pair of positioning parts sandwiching an enzyme electrode having an immobilized enzyme membrane formed by immobilizing a physiologically active substance, and a biosensor body having a pair of positioning parts interposed therebetween; A flexible thin plate that comes into contact with the biosensor in a curved state when combined together, and a diffusion plate that is fixed to the flexible thin plate in a state that covers an opening formed in the flexible thin plate at a location directly facing the enzyme electrode. 1. A diffusion-limiting membrane mounting device for a biosensor, characterized in that it has a limiting membrane. 2. The diffusion-limiting membrane attachment device for a biosensor according to claim 1, wherein the pair of positioning parts are immovably attached to the biosensor. 3. Diffusion in the biosensor according to claim 1 of the above utility model registration claim, in which one positioning part is immovably attached to the biosensor body, and the other positioning part is attached to the biosensor so as to be movable up and down. Restriction membrane attachment device. 4. The biotechnology according to claim 1 of the above-mentioned utility model registration claim, wherein the flexible thin plate is rotated while being engaged with one of the positioning parts, thereby also being engaged with the other positioning part. Diffusion limiting membrane attachment device for sensors.