JPH1114617A - Specimen for liquid sample and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a specimen excellent in reagent quantitative property wherein water-soluble polymer is deposited only to a specified part of a support, by a method wherein the support is composed of polystyrene, and the surface is modified to be hydrophilic and has a region holding a detection layer and a hydrophobic region. SOLUTION: Modification effect of polystyrene in the case of UV ray irradiation is very high as compared with other plastic. When a specified part only is irradiated with UV rays, a modified part and a nonmodified part are very different in the hydrophilic degree, so that the boundary between modification and nonmodification becomes clear. The hydrophilic degree and the area of a hydrophilic part can be hold to be constant by the dosage of UV rays and a mask pattern, respectively. Thereby a specified amount of reagent solution can be hold, and the reagent in a detection layer of a dry specimen can be quantitatively hold only by drying the solution. In a dry system test tool wherein the quantity of supplied samples is constant, measurement precision is improved by making the amount of reagent constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a test strip for analyzing a specific component in a liquid sample, particularly useful for a clinical test.
It relates to a test piece having a detection site directly on a support. The invention also relates to a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, there is a dry type test piece.
The test piece has a detection layer disposed near the tip of a strip-shaped liquid-impermeable (usually made of plastic) support, and there are several types of the detection layer.

(1) One having a porous developing layer such as filter paper on a water-absorbing reagent layer composed of a color reaction reagent and a hydrophilic polymer (acting as a binder polymer), (2)
(3) A color developing reagent directly impregnated into a porous developing layer and dried, and (3) a color developing reagent kneaded with a hydrophilic (or water-soluble) binder polymer is thinly coated on a support. Those that have been dried but do not have a spreading layer, and the like.

A test piece having a porous developing layer as one component of the detection layer can cause the liquid supplied to the porous developing layer to react with the reagents evenly, so that a liquid sample (sample)
However, it is very useful in tests that are so small that a single drop cannot be wasted, such as blood tests. On the other hand, a test piece having no spread layer in the detection layer is used in a dip-and-read test such as a urine test.

[0005] In the case of a test piece having no porous spreading layer, when the liquid sample touches the detection layer, the liquid sample permeates into the polymer, and the color reagent contained in the detection layer and the color reagent contained in the liquid sample are contained. Reacts with a specific component. The resulting color change is measured with the naked eye or an optical device. If the support is light transmissive, the coloration of the detection layer can be measured from the support side.

This type of test piece has a detection layer provided by applying a hydrophilic polymer as a binder thinly (usually at least 5 μm) on a support, so that it differs from a type in which a porous developing layer is impregnated with a reagent. It has the advantage that the reagents can be uniformly contained and the content of the reagent can be freely controlled.

[0007] When preparing this test piece, it is necessary to apply a water-soluble polymer containing a reagent directly on a plastic support as a step. As a material for such a plastic support in a test piece used in the clinical test industry, cellulose acetate, polyethylene terephthalate, polycarbonate, polyethylene, polystyrene, etc., which are inert to a coloring reagent or a specific component, are used. ing. Examples of the water-soluble binder polymer used as a glue include hydroxypropylcellulose, polyvinylpyrrolidone, gelatin, modified gelatin, sodium alginate, and polyvinyl alcohol. The method of applying the water-soluble polymer includes dip coating,
There are various methods such as an air knife method, a curtain coating method, and an extrusion coating method. However, any of these methods often fails to apply well due to the strong water repellency inherent in plastic.

Accordingly, a method has been devised in which a specific portion of a plastic support is subjected to a hydrophilic treatment to increase the bite of a water-soluble polymer containing a reagent on the support. As one of means for making plastics hydrophilic, there is a modification treatment by ultraviolet irradiation (US Pat. No. 5,098,618). When a part of the support is irradiated with ultraviolet rays, the support is immersed in a water tank of the binder polymer aqueous solution, and immediately lifted, the theoretically, the binder polymer aqueous solution adheres only to the part modified by the ultraviolet light, and the remaining part is Does not adhere due to water repellency. Therefore, the reagent is held only in the specific portion.

[0009]

However, in practice, even if the ultraviolet treatment is performed, the hydrophilicity is not so great, or the aqueous solution does not completely adhere due to the incomplete hydrophilicity. The water-soluble polymer adhered to the portion not irradiated with, and various problems occurred. In addition, since the difference in hydrophilicity between the portion irradiated with ultraviolet rays and the portion not irradiated with ultraviolet rays is not remarkable, the boundary between modified and non-modified is not clear, and there is a problem that the quantitativeness is poor. there were. Therefore, an object of the present invention is to provide a test piece for a liquid sample which has excellent reagent quantitativeness in which a water-soluble polymer adheres only to a predetermined portion of a support.

[0010]

In order to achieve the object, a test piece of the present invention comprises a detection layer for analyzing a specific component in a liquid sample, and a test piece comprising a support for supporting the detection layer. In the above, the detection layer comprises a reagent and an alginate which react with the specific component, the support is made of polystyrene, and the surface thereof is modified to be hydrophilic and has a region for holding the detection layer and a hydrophobic region. It is characterized by.

A suitable method for producing the test piece is a step of irradiating a predetermined region of the surface of a support made of polystyrene with ultraviolet rays, and a step of applying an aqueous solution containing a reagent and an alginate to the region irradiated with ultraviolet rays. And a step of drying the attached aqueous solution.

Although polystyrene is a hydrophobic material, according to experiments conducted by the present inventors, polystyrene has a modifying effect upon irradiation with ultraviolet rays (that is, a degree of hydrophilicity compared to other plastics). ) Turned out to be very high. Accordingly, when only a specific region is irradiated with ultraviolet rays, the degree of hydrophilicity between the modified portion and the non-modified portion is significantly different, so that the boundary between the modified and non-modified portions becomes clear.

[0013] Sodium alginate can be said to be more easily drained on the untreated surface of polystyrene and to be more water repellent than other binder polymers used in this field. At the same time, it also strongly adsorbs to the modified hydrophilic part. Therefore, a specific region of the surface of the polystyrene is irradiated with ultraviolet rays, and a reagent solution using sodium alginate as a binder is placed on the surface of the polystyrene. When the polystyrene is tilted, the reagent solution on the non-irradiated surface is easily removed due to its good drainage. On the other hand, since polystyrene has a high hydrophilic effect when irradiated with ultraviolet light, the reagent solution remains completely in the irradiated portion.

The degree of hydrophilicity can be kept constant by the amount of ultraviolet irradiation and the area of the hydrophilic portion can be kept constant by the mask pattern, so that a fixed amount of the reagent solution can be held and the solution is dried. Only by itself, the reagent in the detection layer of the dried test piece can be quantitatively retained. By making the amount of reagent constant, measurement accuracy is improved in a dry test device in which the amount of supplied sample is constant.

[0015]

【Example】

-Example 1-A part of the surface of a polystyrene sheet having a thickness of 1 mm and a molecular weight of 350,000 was irradiated with ultraviolet rays. The UV irradiation device used was PL16-110 manufactured by Sen Special Light Source Co., Ltd., and the lamp used was the same mercury lamp SUV110GS-34 manufactured by Sen Special Light Source Co., Ltd. The irradiation conditions were as follows: the distance between the polystyrene sheet and the lamp was 3 cm, and the irradiation time was 10 minutes.

An aqueous solution of the polymer reagent shown in Table 1 was spotted on the UV-irradiated and unirradiated portions of the polystyrene sheet, and the static contact angle and dynamic contact angle (advance angle, receding angle) of the aqueous solution were measured. Then, the wettability was evaluated. As a contact angle measuring device, CA-X manufactured by Kyowa Interface Science Co., Ltd. was used. The static contact angle was measured 30 seconds after drop application. Also,
The viscosity of the aqueous solution was measured to evaluate the relationship with the wettability. Viscometer RE 100 and Viscometer Controller RC-10 manufactured by Toki Sangyo Co., Ltd.
0A was used.

[0017]

[Table 1]

Table 2 shows the results of the measurement of the wettability of the unirradiated portion, and Table 3 shows the wettability of the portion irradiated with the ultraviolet light and the viscosity of the aqueous solution. It is important that the liquid that is not irradiated with ultraviolet light is hardly wetted by the liquid and that the liquid that has once been wet is easily removed (the liquid is easily drained). For this reason, in Table 2, the static contact angle indicating the wettability, the contact angle hysteresis indicating the liquid drainage property, and the contact angle ratio are described. The liquid drainage is evaluated by contact angle hysteresis because the liquid needs to keep flowing on the solid surface from the wet surface to the dry surface in order to remove the liquid. However, since the ease of detachment from the once-wetted surface is more important than whether it is easy to newly wet the surface, the contact angle ratio with the receding contact angle as a molecule was also evaluated. Therefore, when the contact angle hysteresis is small and the contact angle ratio is close to 1, it can be said that the liquid drainage is good.

Further, it is important that the liquid is easily exposed to the ultraviolet ray irradiated portion and that the difference in wettability from the non-irradiated portion is large in order to secure the quantitative property. For this reason,
Table 3 shows the static contact angle and the degree of modification. Further, since it is desirable that the properties in Tables 2 and 3 do not depend on the viscosity of the liquid, the viscosity of the liquid is described in Table 3.

[0020]

[Table 2]

[0021]

[Table 3]

As can be seen from Tables 2 and 3, in the combination of polystyrene and sodium alginate according to the present invention, regardless of the viscosity of the liquid, the non-irradiated portion of the ultraviolet ray has good water repellency and liquid drainage property, and the ultraviolet ray is irradiated. The wettability of the part was good and the degree of modification was high.

Example 2 A circular pattern having a diameter of 3 mm was drawn on a synthetic quartz glass, and an ultraviolet mask was prepared by depositing chromium on the outer region. The same polystyrene sheet surface as in Example 1 was irradiated with ultraviolet rays through this mask to perform a hydrophilic treatment. An amylase measuring reagent having the composition shown in Table 4 was excessively spotted on the sheet surface, the sheet was tilted to remove the reagent attached to the untreated surface, and the reagent was retained only on the hydrophilic treated surface. The radius r, height h, and static contact angle θ of the droplet were measured to evaluate the amount of retained reagent. Table 5 shows the measurement results.

[0024]

[Table 4]

[0025]

[Table 5] As shown in Table 5, when the reagent aqueous solution containing sodium alginate was attached to the hydrophilic region surrounded by the water-repellent region on the surface of the polystyrene sheet, the reagent was specifically and quantitatively retained with good reproducibility.

As described above, the test strip of the present invention is excellent in quantitativeness of the reagent, so that the measurement accuracy is improved.

Claims (2)

[Claims] 1. A test piece comprising a detection layer for analyzing a specific component in a liquid sample and a support supporting the detection layer, wherein the detection layer comprises a reagent reacting with the specific component and alginate. A test piece for a liquid sample, wherein the body is made of polystyrene and has a region in which the surface is modified to be hydrophilic and has a region for holding a detection layer and a hydrophobic region. 2. A step of irradiating a predetermined area on the surface of a support made of polystyrene with ultraviolet light, a step of applying an aqueous solution containing a reagent and an alginate to the area irradiated with ultraviolet light, and drying the applied aqueous solution. And a process for producing a test specimen for a liquid sample.