JP3624201B2 - Direct fixation of reagent layer by torsional ultrasound - Google Patents

Description

[0001]
[Industrial application fields]
The present invention provides a dry analysis tool (sometimes referred to as a test piece) for measuring a specific component in a liquid usually used in clinical laboratory fields such as urine analysis, serum analysis, whole blood analysis, and immunoassay. The present invention relates to a method for fixing a reagent layer to a base substrate that serves as a support during production.
[0002]
[Prior art]
In the field of clinical examination, analyzing various components in body fluids such as blood, urine, saliva, and cerebrospinal fluid is an index for objectively knowing the diagnosis and treatment effects of many diseases.
[0003]
Reagents are supplied as dry test pieces, and there is no need to prepare reagents in advance such as a liquid reaction. Furthermore, a tool that can measure many items with a small amount of sample has been developed without generating waste liquid. This method is used as an immediate examination method in an emergency laboratory of a hospital, a nurse's office at night, or a practitioner. This method is called dry chemistry.
[0004]
In this dry chemistry technique, the test piece generally comprises a reagent layer and a support. The reagent layer is prepared by impregnating and drying a reagent that reacts with various components in the specimen in a porous matrix such as filter paper, or applying and drying a reagent and polymer binder kneaded with a solvent on a thin resin film. Has been.
[0005]
Even if there is no support, the reagent layer can be cut into strips and used as it is, but when using expensive reagents (eg, enzymes, substrates, color formers, etc.) Such a strip shape is uneconomical if the area used is large, resulting in a very large cost increase.
[0006]
Therefore, the reagent layer is kept in consideration of the size capable of visually colorimetrically maintaining, the light flux (spot diameter) with the reflectometer, the measurement accuracy, the manufacturing handling and the ease of handling in use. Are cut into 4 mm square to 10 mm square squares or rectangles. The cut reagent layer is fixed to a base material serving as a support or a handle with an adhesive (double-sided tape, glue, instantaneous adhesive, etc.).
[0007]
The most commonly used method for directly fixing the reagent layer to the base substrate is a method for fixing with a double-sided tape. However, a polyacrylic resin is mainly used for the adhesive of the double-sided tape, and it contains a lot of polymerization initiator, monomer, stabilizer, plasticizer and wetting agent. When it comes into contact with the reagent layer, The reagent may react with the reagent in the reagent layer to be colored or the active ingredient may be decomposed, and it is necessary to carefully select a double-sided tape for each reagent item.
[0008]
In addition, the adhesive on the double-sided tape adheres to the processing machine in the processing process, causing trouble, or the adhesive adheres to the surface of the reagent layer, causing a portion where the reagent and the sample do not react, resulting in uneven coloring. was there.
[0009]
A method of fixing with hot melt (a thermoplastic resin that softens at 80 to 150 ° C.) is used as a method for solving the harmful effects of double-sided tape, but the temperature of the entire reagent layer is set to a few seconds to melt the hot melt. It is necessary to raise the temperature to 100 to 110 ° C., and as a result, there is a risk of denaturing the substances in the reagent layer (particularly proteins such as enzymes, antibodies, and antigens). In addition, plasticizers, stabilizers and the like are mixed in the hot melt as well as the double-sided tape, and these components have a considerable adverse effect on the reagent.
[0010]
As a solution, Japanese Examined Patent Publication No. 53-6551 discloses a method of wrapping a test piece with a woven fabric or a web, and thermally fusing the side with hot melt. In Japanese Patent Publication No. 6-68488, a thermoplastic resin is sandwiched between a reagent layer and a support, and the laminate is cut with a laser or an ultrasonic wave and fixed on a melted cut surface. A method is disclosed.
[0011]
The method of wrapping the reagent layer with nylon mesh and heat-sealing both sides solves the above two problems, but the nylon mesh is slightly loosened due to impact during transportation, and the reagent layer shifts as a result of loosening, or There was a risk of getting it. Further, this processing method has an economical disadvantage that it is complicated and very expensive.
[0012]
The technique disclosed in Japanese Examined Patent Publication No. 6-68488 is a method for producing a dry-type multilayer analysis tool without using an adhesive, but the tool thus produced is further placed on a rod or holder to be a handle. This is a type to be used later, and a wasteful portion is generated because the margin is cut out with a laser or an ultrasonic wave. Also, a machine that generates a high-power laser or ultrasonic wave that can cut off the material is required, and such a machine is usually expensive.
[0013]
In particular, when fixing an antibody used for analysis of trace components using immune reaction (so-called dry immunoassay) or glass fiber filter paper chemically bound with antigen, avidin, biotin, etc. to a base substrate, double-sided tape or hot melt In addition to the above-mentioned problems, there is a problem that unreacted components and substances that affect the reaction in the sample are adsorbed non-specifically on the glass fiber filter paper, resulting in a large error.
[0014]
These problems are caused by the fact that a non-thermoplastic or thermoplastic resin reagent layer is placed in contact with a thermoplastic resin base material, and frictional heat is generated by applying ultrasonic vibration and pressure from the outside. And melting the surface of the base substrate in contact with the reagent layer, so that one of the melted surface materials penetrates into the other, or the other surface material is melted in the same manner as the melted one surface material It is solved by fixing directly by bonding them together and then lowering the temperature by stopping vibration by ultrasonic waves. Hereinafter, this method may be expressed as ultrasonic fusion.
[0015]
Since the heat generated at this time is instantly generated on the surface of the layer and quickly cooled, the reagent in the reagent layer is hardly denatured. Moreover, since the base material base which is a support and the reagent layer are directly fixed, there is no blank portion to be cut off, which is an economical method. Since this method directly transmits ultrasonic vibrations to the reagent layer, the ultrasonic oscillator can be a relatively inexpensive type.
[0016]
[Problems to be solved by the invention]
When the reagent layer is made of a thin thermoplastic resin film coated with a reagent, these films generally have a thickness of 50 μm to 150 μm. Further, in some cases, thinner (about 20 μm) ultrathin films are also used. However, it was found that when the film as the reagent layer is extremely thin like this, the ultrasonic waves pass through the film, and the concentration of vibration energy due to the ultrasonic waves does not occur on the surface, so that the ultrasonic fusion described above cannot be achieved.
[0017]
[Means for Solving the Problems]
Here, the inventors have found that the above-mentioned problems can be solved by using “torsional ultrasonic waves” with respect to ultrasonic waves that cause friction, and the present invention has been completed.
That is, the present invention includes the following steps in a method of directly fixing a reagent layer comprising an ultrathin thermoplastic resin film coated with a reagent onto a base substrate serving as a support.
(1) A step of melting the surface of the reagent layer in contact with the base substrate by placing the reagent layer in contact with the base substrate and applying vibration from torsional ultrasonic waves and external pressure.
(2) Step of integrating the melted reagent layer surface and the base substrate surface by applying pressure (3) Step of releasing torsional ultrasonic vibration and pressure
The concept of “torsional ultrasonic waves” used in the present invention is the greatest feature that it is “ultrasonic waves having transverse vibrations”, and is a concept that contrasts with generally used ultrasonic waves being longitudinal vibrations. It is.
As an image of this “torsional ultrasound”, it is recommended that the shape of the mouth be pressed against the surface with the cup of a perfect circle lying down, and the scene of twisting without shifting the perfect circle. The edge of the cup is the horn of the ultrasonic oscillator, and the twisting motion corresponds to lateral vibration.
[0019]
Normal longitudinal vibration ultrasound cannot melt an ultra-thin thermoplastic film, but transverse vibration ultrasound "torsional ultrasound" can transmit vibration energy to the surface of the ultra-thin film, Therefore, an extremely thin film can be melted. That is, an ultrathin film can be fused onto the base substrate, and a test piece using the ultrathin film as a reagent layer can be produced.
[0020]
The method of applying the reagents onto the thermoplastic film may be a method usually performed in this field. That is, what knead | mixed the reagents with the solvent with the polymer binder etc. is apply | coated on a film with a coating machine.
[0021]
The shape of the base substrate serving as the support is plate-like, but the material may be made of a thermoplastic resin or a non-thermoplastic material. Examples of the thermoplastic resin include polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, polycarbonate, polyvinyl acetate, polyvinyl chloride, cellulose ether and the like. Examples of non-thermoplastic materials are paper, wood, glass fiber, metal cloth, non-woven fabric (membrane filter, uniaxially stretched porous film, biaxially stretched porous film, radiation irradiated porous film), sintered body, porous Although a ceramic sheet etc. are mentioned, it is desirable to have a fine hole.
[0022]
When the support is a thermoplastic resin, the melted resin from the reagent layer and the resin from the support melted by ultrasonic waves are fixed integrally. When the support is a non-thermoplastic material, the melted resin from the reagent layer bites into the fine pores of the support and is fixed by the so-called “wrinkle effect”.
[0023]
The reagent layer and the substrate base are arranged, and a torsional ultrasonic vibration with a frequency of 40 kHz and a pressure of 60 to 80 kg / cm ² are applied. This state is maintained for a few seconds with 0 comma, and then the ultrasonic vibration is stopped. The pressure is released after the pressure is maintained for another few seconds with only the pressure. After this step, the reagent layer and the base material base are fixed.
[0024]
【Example】
Hereinafter, an example of a method for producing a dry analysis tool (test piece) having a reagent layer fixed by the method according to the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited by the examples.
[0025]
As an example, a test piece for detecting nitrite in urine was prepared according to the following formulation.
(Prescription)
d-Naphthylamine 1.0 g
Sulfanilamide 2.5g
Trichloroacetic acid 3.0g
Polyvinyl butyl acetal 20.0g
100 ml of methanol
・ Plastic resin plate (used as support / base plate, in the figure, base material (1)) ……………… Thickness 0.3mm PET film • Thermoplastic resin film (used as reagent layer, In the figure, (2)) ……………… Tape-like PET film with a width of 1 cm, thickness 20 μm
・ Ultrasonic oscillators …………………… 900 series “947M” manufactured by Emerson Japan Inc.
A coating solution was prepared based on the formulation shown in the previous table, and this was coated on the film with a coating machine at a thickness of 400 μm and dried with hot air to obtain a reagent layer (reagent layer ▲ 2 in the figure). ▼).
The obtained reagent layer (2) was allowed to stand on the base substrate (1), and torsional ultrasonic vibration with a frequency of 40 kHz and a pressure of 70 kg / cm ² were applied. This state was maintained for 0.2 seconds, and then the vibration was stopped, and the pressure was released after the pressure was maintained for another 0.2 seconds.
The shape of the ultrasonic oscillating horn at this time is a cylindrical shape with a concentric outer circle diameter of 6 mm and a concentric inner circle diameter of 4 mm. The fused state at this time is as shown in FIG. Affixed in a circular shape only to the peripheral part away from the center. As shown in FIG. 3, the diameter of the circle is 6 mm for the diameter of the concentric outer circle and 4 mm for the diameter of the concentric inner circle.
The test piece in the state of FIG. 1 completed as described above was cut into a width of 1 cm to obtain the test piece shown in FIG.
[0027]
When this specimen was applied to nitrite-containing urine, it showed good red coloration depending on the nitrite content.
[0028]
When the ultra-thin film as described above is used as a reagent layer, a test that does not cause fusion with the use of torsional ultrasonic waves as described above, even though ordinary ultrasonic waves do not cause fusion, does not cause a decrease in activity. I was able to create a piece.
[0029]
【The invention's effect】
According to the method of the present invention, no pressure-sensitive adhesive / adhesive (double-sided tape, hot melt, etc.) is used.
In addition, since no adhesive is used, there is no physical failure due to adhesion of glue or the like, and costs are reduced. Since an inexpensive ultrasonic oscillator is used, the equipment machine can be made simple and inexpensive from the viewpoint of production equipment, and the process can be simplified, so that the manufacturing cost can be reduced.
Furthermore, even when an ultrathin film that does not cause energy concentration in normal ultrasonic waves is used as a reagent layer, ultrasonic fusion can be reliably performed.
[Brief description of the drawings]
FIG. 1 is a plan view and a front view of a test piece according to the present invention before cutting.
FIG. 2 is a plan view of the test piece according to the present invention after cutting.
FIG. 3 is an enlarged plan view of the tip portion of the test piece of FIG.
[Explanation of symbols]
(1) Support (base material base)
(2): Reagent layer (thermoplastic ultra-thin film)
▲ 3 ▼; Fusion location

Claims (2)

A method for producing a dry analytical tool for measuring a specific component in a liquid, wherein a reagent layer comprising an ultrathin thermoplastic resin film coated with a reagent is directly fixed on a base substrate as a support And a fixing method comprising the following steps.
(1) A step of melting the surface of the reagent layer in contact with the base substrate by placing the reagent layer in contact with the base substrate and applying vibration from torsional ultrasonic waves and external pressure.
(2) Step of integrating the surface of the melting reagent layer and the surface of the base substrate by applying pressure (3) Step of releasing torsional ultrasonic vibration and pressure The method according to claim 1, wherein the thickness of the ultrathin thermoplastic resin film is 10 μm to 50 μm.

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