JPH01173868A - Fiber structure for liquid development - Google Patents

Abstract

PURPOSE:To provide a porous development layer for liquid development which can be controlled in development area over a wide range without losing the metering effect by using a knitted fabric consisting of fibers formed by roughening the surfaces of polyester filaments contg. 0.5-5wt.% silica having 10-70mum average particle size. CONSTITUTION:The knitted fabric is formed of the polyester filaments added with 0.5-5wt.% silica effective for surface roughening of the polyester filaments in the later stage at 10-70mum average particle size. The knitted fabric is so constituted as to have ¦course-well¦<=10 pieces/SUN, 130-180g/m<2> METSUKE, >=70% reflectivity at 500nm, 7.2-8.0 elution pH and 40-90% voids. Further, the surrfaces of the polyester filaments are roughened by a surface roughening treatment so that the filaments have 35-150mm/10min water absorption length and about <=10sec wicking. The porous development layer for liquid development is formed by using the knitted fabric constituted in such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a porous spreading layer of an improved dry integrated analytical element for analyzing specific components in liquid samples.
More specifically, the present invention relates to a porous spreading layer of an integrated multilayer analytical element useful for the analysis of aqueous liquid samples, particularly for clinical tests using liquids as samples.

<Prior art> Conventionally, as a form of dry analytical element, a transparent support is provided with a water-absorbing reagent layer containing a coloring reaction reagent and a hydrophilic polymer binder, and a porous development layer as the outermost layer. Many multi-level body analysis elements have been proposed. The porous spreading layer can contain a point-supplied aqueous liquid sample (e.g., whole blood, plasma, serum, lymph, saliva, cerebrospinal fluid, urine, alcohol, waste water, etc.). The action of spreading the components in the lateral direction without substantially unevenly distributing them and supplying them to the reagent layer containing the water-absorbing hydrophilic polymer or the water absorption length at an approximately constant rate per unit area (metering action) ).

As the porous spreading layer, Japanese Patent Application Laid-open No. 49-53888,
U.S. Patent No. 3,992,158, Japanese Unexamined Patent Publication No. 55-9085
No. 9, JP-A-55-164356, JP-A-Sho 5
7-66359, Japanese Patent Application Laid-Open No. 57-148250, etc. ◎Problems to be Solved> Among these, development 1 of eel made of woven and knitted fabrics is difficult to solve when blood is used as a sample. It is a porous developing layer that can develop blood, plasma, and serum well, and is excellent in various aspects such as ease of manufacturing an integrated multilayer analytical element and durability of the element. However, it has been found that it is difficult to control the spread layer made of woven fabric to change the spread area from a specific range while maintaining the metering effect. In other words, when the content of the component to be analyzed in an aqueous liquid sample is small, it is desirable to reduce the area on which the liquid sample is developed. This is because even if one attempts to do so, it cannot be easily realized, or the metering pH tends to be incomplete although the developed area can be made smaller.

The object of the present invention is to overcome these drawbacks of textiles and provide a porous spreading layer made of a new material that allows control of the spreading area over a wide range without impairing the metering effect.

<Means for solving the problem> That is, the present invention is a knitted fabric made of polyester yarn containing 0.5 to 5% by weight of silica with an average particle diameter of 10 μm to 70 μm, and 1 course/well 1≦10 yarns. /inch, basis weight 130-180t/rn'', reflectance at 500nm 70cm or more, elution...7.2-8.0,
A liquid deployable fiber structure having a porosity of 40 to 90%, preferably in which the polyester yarn has a roughened surface and a water absorption length of 35 m to 35 m. 150■/10 minutes, tights king 10
This is a fibrous structure for liquid deployment that takes less than a second.

The polyester yarn of the present invention has an average particle size of 10 μm or more.
Contains 0.5 to 5 ff1t+t% of 70 μm silica.

This silica is effective for roughening the surface of the polyester yarn in a later process, and the roughening with silica has an important effect on the adhesion between the reagent layer containing the hydrophilic polymer or the water absorption length and the spreading layer. give.

If the particle size is 10 μm or less, the thickening effect during spinning is large, and the particles tend to aggregate, causing fluff,
Yarn breakage occurs, making it difficult to manufacture yarn.

In addition, in the case of particle threads of 704 m or more, the degree of roughness in the subsequent process is too large, and the effect of improving adhesion is limited. The amount of silica added is preferably 0.5 to 5% by weight, and 0.5 to 5% by weight.
．． If it is less than 5% by weight, the degree of roughening after the roughening treatment in the subsequent step will be small, and the effect of improving adhesion will be small. Also, if more than 5 layers are added, there will be many problems in spinning, and even if the quality is good, the yarn cannot be removed.

The polyester yarn used in the present invention may have a structure in which 80 moles or more of the yarn is polyethylene terephthalate, and may be modified by copolymerization, blending, etc. Further, the yarn may be either a filament or a spun yarn, but filaments are preferable because they tend to be homogeneous.

A knitted fabric is produced using this yarn. For knitting, warp stockinette,
There are various types of knitted fabrics, such as weft knitted fabrics, but smooth knitted fabrics are desirable from the viewpoint of uniformly spreading the liquid supplied in dots.

The number of knitted courses and wells is preferably 65 to 85 per inch. If it is less than 65 pieces/inch, the no-turning property will be poor.
If it is 85 threads/inch or more, the contact area between the blood and the thread becomes too large and hemolysis is likely to occur. In addition, in order to spread uniformly, the course density and the sea urchin/' density are 1 course - well 1 ≦
It is necessary to satisfy lO books/inches. Outside this range, the liquid will not develop in a circular shape, but will develop in an elliptical shape, impairing the metering effect. In addition, after the liquid has been developed to some extent, it is desirable that it penetrates in the thickness direction of the developed layer, and the basis weight of the knitted fabric is preferably 130 to 180 r/ro.
If the basis weight is less than 1llI', it will penetrate in the thickness direction before developing in the lateral direction, and if it is more than 180f/&, it will take too long to penetrate in the thickness direction. Further, in order to spread the liquid laterally at an appropriate speed, the porosity is preferably 40 to 90 inches. If the porosity is over 90%, the metering effect will be lost because it will penetrate through the thickness before expanding laterally.
If it is less than 40%, it will take time to expand laterally and it will be difficult to expand smoothly. Further, when measuring components contained in a liquid sample by color reaction or the like, it is preferable that the developing layer itself is not colored, and the reflectance of visible light is 70% or more, preferably 80% or more.

It is desirable that the reflectance at a typical visible light wavelength of 5 Q Q nm is at least 70% or more. Moreover, for elution of the spreading layer, 7.2 to 8.0 is preferable. Particularly when developing blood, this range is preferable because it has little effect on each component in the blood.

Next, typical methods for roughening the surface of the polyester yarn include subjecting the silica-containing polyester yarn to a reduced i elution treatment using an alkaline solution, and surface etching using a low-temperature plasma discharge treatment. The former can be reduced by 0.2 to 0, for example, by treatment with several grams of caustic soda in a high-temperature bath or by continuous weight loss by dry heat treatment after adhering to a high concentration of caustic soda.
．． A fiber surface with an unevenness of 7μ is obtained. The latter surface etching using low-temperature plasma is carried out by glow discharge in an inert gas or gas atmosphere such as air or oxygen. In this case, the yarn that has been treated with an alkali solution may be further etched by low-temperature plasma, or the yarn that has not been treated with an alkali solution may be etched by low-temperature plasma. The roughened surface produced by plasma treatment may have slightly smaller irregularities than the roughened surface produced by alkaline solution, but since the silica in the system shields the plasma, only the periphery of the silica particles is selectively etched, increasing the etching efficiency. In other words, it has good surface roughening efficiency.

Also, as a matter of course, a rough surface having a shape different from that of the conventional plasma etched surface of polyester is formed. Furthermore, in the case of plasma etching, -C is added to the fiber surface.
Functional groups such as =O1-CUOH1-OH are formed, and the wetting characteristics for liquids can be improved at the same time. A knitted fabric with a water absorption length of 35 mm to 150 m/10 minutes and a wicking time of 10 seconds or less is highly desirable for development.

The most preferred method for this purpose is the plasma etching treatment described above. The treatment may be performed on at least one side, and both sides may be treated. However, the method is not limited to this, and a surfactant that does not worsen hemolysis may be attached to the knitted fabric.

However, for elution, it needs to be between 7.2 and 8.0. In particular, it is necessary to thoroughly neutralize and wash the product after using caustic soda. Low-temperature plasma treatment is most preferred from the viewpoint of elution and wettability. By roughening these surfaces, it is possible to strengthen the adhesive force with the lower layer or control the development area.

However, the reflectance was measured using a spectrophotometer (Macbeth MS2020).
Measure the sample by applying it to the

In addition, for elution, weigh 2 Or of the fiber structure using a top balance, cut it into several pieces, put the sample in an Erlenmeyer flask containing 300 WLl of ion-exchanged water in advance, stir it several times, completely submerge it, and seal it. . After leaving this at room temperature for 2 hours, about 20
This is a value measured with a meter after pouring 0d of liquid into a beaker.

The porosity v% is determined by Jll Sameter (JIS L-10
18. Measure the thickness am of the knitted fabric at a load of 7r/i),
Next, weigh the 10(7) x 10(7) sample and
This value is calculated from the following formula, where b is the number. The specific gravity of the polyester is 1.4.

”-((10x 10 x a/10-b/1.4)
/(IOX 10x a/10) )X100 (%)
The water absorption length was determined by soaking the item in boiling ion-exchanged water for 10 minutes, drying it, keeping it in a room at 20°C and 65F4 for one day and night, and then measuring it according to the JIS L-1o96 B method. and the average value in the well direction.

After wicking is treated in the same way as for water-absorbing bamboo, JIS
Measured by L-1096A method.

A drawn yarn of polyethylene terephthalate (4 mm, 50 d/36 f) containing 3 weights of Snowtex 20 L (manufactured by Aji Co., Ltd.) was prepared, and a smooth knitted fabric was knitted using a 40GX33'' double-jersey circular knitting machine.

This was relaxed and treated with NaOH409/l.
After alkali treatment at 5°C for 60 minutes and neutralization with acetic acid,
Rinse with warm water at 50°C for 20 minutes three times, and then wash at 170°C.
Heat set treatment was performed for ×60 seconds.

(Sample A) Also, the sample after relaxation was treated with 1
A heat setting process was performed at 70°C for 60 seconds.

(Sample B) Samples A and B were also treated in a low-temperature plasma processing machine with a high-frequency power source of 13.56 M) Iz and placed in an oxygen gas atmosphere of 0. One side was etched at I Torr for 120 seconds. (Each sample is designated as C1D) A colorless transparent polyethylene terephthalate (PET) film (support) with a thickness of 185 μm covering a gelatin undercoat layer is coated with the following ingredients to coat a glucose layer with a thickness of approximately 15 μm. A measurement reagent layer was provided by applying an aqueous solution and drying it.

Component composition of glucose measuring reagent j- (coating layer) Glucose oxidase 1500 U/i Peroxidase 2500 U/rn 1,7-dihydroxynaphthalene 500 μ/m 4-aminoantipyrine 1.2 f/rl Deionized gelatin
20f/m” nonylphenoxy polyethoxyethanol (contains an average of 10 ethylene units) 2
00η/d On top of this reagent layer, a light shielding layer having a dry thickness of about 7 μm was coated using an aqueous dispersion and dried to form the following component coating layer.

Component composition of light shielding layer (amount of C1) Deionized gelatin 3.0 P/zenonylphenoquine polyethoxyethanol (A-xyethylene unit average content: 10) 200η/male titanium dioxide fine particles
13? An adhesive layer having a thickness of approximately 5 μm was coated on one layer at the speed of light of /rd using an aqueous solution in the coating amount of the following components and was then dried.

Component composition of the adhesive layer (coating amount) Deionized gelatin 6.79/rn' Nonyl phenoxybolyethoxyethanol (oxyethylene unit average 1O content) 70~/rf11 Then, water was almost uniformly supplied to the surface of the adhesive layer. 4 types of smooth fried fabrics A, B, C, and D (for those treated with plasma, the treated side faces the adhesive) are layered on top of it, and the whole is placed between pressure rollers. An integrated multilayer analytical element for glucose measurement was prepared by passing through the sample and laminating it almost uniformly by applying light pressure to provide a developing layer.

At the same time as measuring the peel strength between the spreading layer and the adhesive layer, 10 µm of human serum was dotted thereon and the state of spreading (lateral uniformity, spreading time) was observed with the naked eye. The results are shown in Table 1.

The knitted fabric of the fibers roughened with alkali shown in Margin A below was developed uniformly in a circular shape, although it took some time for the serum to develop.

The knitted fabric B, which did not have a roughened structure, had low adhesion to the contact f layer and took time for the serum to spread, but it spread uniformly in a circular shape. C1, which was roughened by alkali and further etched by low-temperature plasma, and D, which was treated only by low-temperature plasma etching, had sufficient adhesive strength and the serum was spread smoothly, making them excellent as spreading layers. It was something.

Patent applicant RiRashi Co., Ltd. Fuji Photo Film Co., Ltd.

Claims (1)

[Claims] 1) Silica with an average particle diameter of 10 μm to 70 μm is
It is a knitted fabric made of polyester yarn containing 5% by weight, |Coarthwell|≦10 yarns/inch, and has a basis weight of 130~
180g/g^3, reflectance at 500nm is 70%
Above, elution pH is 7.2-8.0, porosity is 40-90
%. 2) The polyester yarn has a roughened surface and has a water absorption length of 35m.
2. The fibrous structure for liquid deployment according to claim 1, wherein the wicking is 10 seconds or less at m~150 mm/10 minutes.