JP2003254876A - Filter for tip and the tip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter for a tip and a tip using the filter that can guarantee quantitative dispensing operation with a high precision and repeatedly use under an autoclave process, and also be reduced into a tip from which liquid can be recovered even if an overpipetting accident occurs. <P>SOLUTION: The filter for the tip has preferably air permeability fragile of 0.1-20 cc/cm<SP>2</SP>sec on the filter 6 for the tip including a porous layer with water pressure resistance of 4 KPa or more. The tip is formed by loading the filter 6 for the tip into a tip body 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid suction device, a filter for a chip to be mounted on a chip to be mounted on a pipette or the like, and a chip using the filter for preventing overflow during oversuction. It is useful.

[0002]

2. Description of the Related Art In the inspection of body fluids such as blood and urine, a tip is attached to the nozzle of a liquid suction device, a predetermined amount of reagent solution is aspirated and stored in the tip by suction, and this reagent solution is tested by releasing it. Dispensing is performed on a dispensing plate, and the reagent is further dispensed to this dispensing reagent solution in the same manner as above. In the dispensing of the above-mentioned test solution or reagent, the nozzle part of the suction device should not be attached and stained with the test solution or reagent, and if it is not a clean room,
It is necessary that the nozzle is not attached and damaged by dust in the air.

Therefore, although a porous filter has been used conventionally, it is effective in blocking the contaminated passage, but when it is sucked excessively, liquid is sucked into the suction device or its nozzle portion. Most of them cannot prevent inflow, so-called overflow.

In order to avoid this overflow problem, a porous body containing an additive for self-sealing, which immediately seals the pores when it comes into contact with a liquid, is proposed (US Pat.
156,811). An apparatus in which such a porous body is loaded on a chip is also effective in preventing contamination during normal use and preventing contamination due to oversuction (overflow).

[0005]

However, since the additive for self-sealing the porous body contains sodium and other compounds, there is a possibility of potentially contaminating the sample. For example, the aerosol generated during the first inhalation of the liquid may fall into the sample after contacting the porous body and acquiring sodium from the self-sealing additive. As a result, the sample is significantly contaminated. Some samples are worth hundreds of thousands of yen, and such sample contamination often results in significant damage.

Further, when oversuction occurs, the liquid in the pipette tip comes into contact with the porous body, and the porous body itself is sealed so as to be closed. In such a state, even if the pressure is applied from the upper side (nozzle side), there is no effect, so that the liquid cannot be collected unless the chip is separated.

Further, when pressure is applied to the self-sealing additive used for the porous body, moisture may be induced by the pressure, and the self-sealing additive may be activated to close the porous body. For this reason, there is also a problem that autoclave sterilization cannot be performed with chips using the self-sealing additive.

It is known that the effect of blocking droplets is enhanced by increasing the water repellency of the chip filter or by reducing the pore size. However, if the pore size is too small, the suction property is deteriorated. I have a problem. Therefore, for the tip filter, to prevent overflow,
Until now, there has been no literature that describes or suggests a suitable water pressure resistance.

Therefore, an object of the present invention is to provide a chip which can guarantee highly accurate quantitative dispensing, can be repeatedly used under an autoclave process, and can recover liquid even if an oversuction accident should occur. It is to provide a chip filter capable of achieving the above, and a chip using the filter.

[0010]

The above objects of the present invention can be achieved by the present invention as follows. That is, the chip filter of the present invention is characterized by including a porous layer having a water pressure resistance of 4 KPa or more. In addition, this filter has a breathable fragile of 0.1 to 20 cc / cm ² · se.
It is preferably c.

On the other hand, the chip of the present invention is characterized in that the chip filter described in any one of the above is mounted on the chip body.

[Operation and Effect] According to the filter for a chip of the present invention, since it includes a porous layer having a water pressure resistance of 4 KPa or more,
As shown by the results of the examples, it is effective in preventing overflow during oversuction. At this time, since it does not contain additives for self-sealing, there is almost no possibility of contaminating the sample, highly accurate quantitative dispensing can be guaranteed, and it can be repeatedly used under the autoclave treatment. Furthermore, since the holes are not blocked, the liquid can be recovered even if an oversuction accident occurs.

The breathable fragile is 0.1 to 20 cc / c
In the case of m ² · sec, a certain level of air permeability can be obtained, so that the responsiveness in the suction operation is improved, and highly accurate quantitative dispensing can be performed more reliably.

On the other hand, since the tip of the present invention is loaded with the tip filter having the above-mentioned effects on the tip body, it is possible to guarantee a highly accurate quantitative dispensing and to repeatedly use it under the autoclave treatment. Even in the unlikely event of an over-suction accident, the liquid can be collected.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a usage state of a chip loaded with the filter for a chip of the present invention.

The tip filter of the present invention has a water pressure resistance of 4
The filter is characterized by including a porous layer of KPa or more, and the filter includes a porous body formed of only the porous layer, and a laminated layer in which a porous layer having a low water pressure resistance is further laminated. It can be the body. In the present invention, the water pressure resistance is 4 KPa
A porous sintered body made of a resin can be used as the above-mentioned porous layer or as a porous layer having a low water pressure resistance laminated thereon.

The water pressure resistance of the porous layer in the present invention is 4K.
Although it is Pa or more, 5 to 200 KPa is preferable, and 20
-100 KPa is more preferable. Such water pressure resistance is
The water pressure resistance can be increased mainly by adjusting the pore diameter and material of the porous layer. The smaller the pore diameter of the porous layer or the greater the water repellency of the material, the higher the water pressure resistance can be.

Further, in the present invention, from the viewpoint of obtaining high air permeability while effectively preventing overflow at the time of oversuction, the thickness of the above-mentioned porous layer having high water pressure resistance is made thin and the thickness for reinforcement is provided. Those having a structure in which porous layers having a large size are laminated are preferable. In that case, the high water pressure resistant porous layer may be provided on at least one of the inside, the upper surface and the lower surface of the chip filter 6, but for the reason of preventing erroneous insertion in the upper surface and lower surface directions when the filter is inserted. More preferably, it is provided inside the chip filter 6. The thickness of the high water pressure resistant porous layer is preferably 1 to 500 μm, and 30 to 200 μm.
Is more preferable.

As shown in FIG. 1, the tip filter has a shape corresponding to the shape of the inner peripheral surface of the tip body 3, but a generally cylindrical shape is generally used. The substantially cylindrical tip filter 6 is slightly deformed by being loaded (fitted) in the tip body 3, and can be fixed to the inner peripheral surface of the tip body 3 by the elastic restoring force at that time.

As the porous layer or the porous body in the present invention, a porous sintered body, a fiber assembly, a porous membrane, an open cell foam or the like can be used, but the porous sintered body is the main material. It is preferably used.

When a porous sintered body is used, a sintered resin porous body made of a powder of polyolefin such as ultra-high molecular weight polyethylene or polypropylene and a fiber can be used as the porous sintered body. Further, it is also possible to use a sintered resin porous body on which the above-mentioned high water pressure resistant porous membrane is laminated, or a resin coating which improves water pressure resistance.

The maximum inner diameter of the porous sintered body is preferably 5 to 10 mm, and the thickness of the porous sintered body is preferably 0.5 to 7 mm as described later.

As shown in FIG. 1, in order to dispense a test solution or a reagent using a chip loaded with the chip filter 6 of the present invention, as shown in FIG. And the test solution 5 and the like are sucked into the chip by the operation of the piston 1 of the suction device. In this case, the filter 6 can prevent the test solution 5 from passing through the aerosol 4, can prevent the test solution 5 from overflowing during oversuction, and can recover the liquid even if an oversuction accident occurs.

In order to produce the above-mentioned porous sintered body, polyolefin powder, especially ultra high molecular weight polyethylene (viscosity average molecular weight of 500,000 to 10,000,000, preferably 1,000,000 to 7) is used.
(1,000,000 items) is charged into a mold, the powder is pressed at a predetermined pressure, and then sintered in a heating furnace maintained at a temperature equal to or higher than the melting point of ultra-high molecular weight polyethylene, and then cooled to release from the mold. A method can be used in which the block-shaped porous body is taken out, the block-shaped porous body is cut into a sheet, and the sheet is punched into a predetermined shape or cut into a predetermined shape.

Further, ultrahigh molecular weight polyethylene is filled in a mold, heated at a temperature lower than the melting point of the polyethylene, and then pressurized to obtain a preform, which is placed in a reduced pressure atmosphere. Remove the air in the molded product,
Then, after sintering in steam heated above the melting point of the polyethylene, to obtain a block-shaped porous body by cooling, cutting the block-shaped porous body into a sheet,
This sheet can be punched into a predetermined shape or cut into a predetermined shape.

The water pressure resistance and the average pore diameter of the porous sintered body are
Can be prepared by the particle size of ultra high molecular weight polyethylene powder,
In order to obtain a compression elastic modulus and an average pore size described later, the particle size of the ultra high molecular weight polyethylene powder is preferably 30 to 170 μm, more preferably 60 to 120 μm. Examples of ultra-high molecular weight polyethylene include HiZex Million (manufactured by Mitsui Chemicals, Inc.) and Hostalen GUR
Commercial products such as (manufactured by Thai Kona) are available.

The average pore diameter of the porous sintered body is 4
When used as a porous body of KPa or more, it is usually 10
The thickness is 100 μm, preferably 20 to 40 μm. 10
If it is less than μm, the suction pressure at the time of dispensing needs to be considerably high, which makes the suction work difficult, and if it exceeds 100 μm, it tends to be difficult to completely prevent passage of the reagent solution and the like.

The resin powder of the above-mentioned porous sintered body has a solvent resistance, acid resistance, alkali resistance, hygiene property, dust-free property, radiation resistance, autoclave resistance, mechanical strength, etc. Molecular weight polyethylene is preferred, but it is also possible to use polypropylene powder.

The thickness of the above-mentioned porous sintered body is set according to the form of the pipette and the reagent or reagent to be dispensed, but it is usually 0.5 to 7 mm, preferably 1.5 to 5 mm.
It is said that However, the thickness may exceed 7 mm.

When the water pressure resistance of the above-mentioned porous sintered body is less than 4 KPa, lamination with a fluororesin porous film such as a PTFE porous film or a water repellent coating for improving water pressure resistance is possible. Further, the heat resistance can be improved by increasing the crosslink density by electron beam irradiation.

Water pressure resistance of 4 KP laminated on the porous sintered body
Examples of the porous layer of a or higher include a fluororesin porous film. The average pore diameter of this porous membrane is 0.2
˜5 μm is preferred. Examples of the fluorine-based resin include polytetrafluoroethylene (PTFE), polytetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene / hexafluoropropylene copolymer (FEP), and the like.
The method for laminating the sintered porous body and the above-mentioned porous membrane layer is not particularly limited, but usually, the porous membrane can be laminated by heat welding to the sintered porous body. Further, a lamination method using an adhesive can be adopted for the lamination of the porous films.

Further, the water-repellent coating may be formed by forming the above-mentioned fluororesin coating layer, and a method of impregnating a dispersion, a method of applying a dispersion, or the like can be adopted. When these dispersions are dried, they are fixed to the surface of the sintered porous body to form a fluororesin coat layer. The dispersion may be fired.

The air permeable fragile of the chip filter of the present invention is 0.1 to 20 cc / cm for the above-mentioned reason.
² · sec is preferable, and 1 to 5 cc / cm ² · sec is more preferable. Is less than 0.1cc / c m ² · sec Conversely, the suction work must be much higher suction pressure at the time the dispensing becomes difficult and full of reagent such exceeds 20cc / cm ² · sec It tends to be difficult to block passage. Therefore, when the chip filter of the present invention is formed of a single-layer porous body, it is preferable that the air permeable fragile of the porous sintered body be in the above range, for example.

On the other hand, in the chip of the present invention, as shown in FIG.
It is loaded. The tip body 3 generally has a tapered shape (a spoid shape) or a shape including a tapered portion and a straight pipe portion. The chip body 3 can be manufactured by injection molding of a resin having excellent solvent resistance, acid resistance, alkali resistance, hygiene property, dust-free property, radiation resistance, autoclave resistance, mechanical strength and the like, for example, polycarbonate. Further, a polyolefin resin such as polypropylene can be used as a general-purpose chip.

[0035]

EXAMPLES Examples and the like specifically showing the constitution and effects of the present invention will be described below. In addition, measurement and evaluation of physical properties in Examples and the like were performed as follows.

(1) Average pore size It was measured by a mercury porosimeter (mercury intrusion method).

(2) Breathable Frazier Ventilation according to JIS L1096 8.27.1A method
Degree (unit: cc / cm ² -Sec) was measured.

(3) Overflow test 96 pieces of 100 μl were obtained from the obtained Example products and Comparative Example products.
It was attached to a polypropylene pipette tip for use with tweezers, a 200 μl oversuction test was performed, and the presence or absence of overflow was evaluated.

Example 1 An ultrahigh molecular weight polyethylene powder (average particle size 120 μm) having a viscosity average molecular weight of 4.5 million was filled in a mold and heated at a temperature slightly lower than the melting point of the ultrahigh molecular weight polyethylene for 6 hours, and this filling was performed. The powder was pressed to adjust the density, then sintered and then cooled at room temperature to obtain a round rod porous body. This was cut to obtain an ultrahigh molecular weight polyethylene porous sheet having a thickness of 2 mm, a water pressure resistance of 4 KPa, a breathable Frazier 0.8, a porosity of 28%, and an average pore diameter of 30 μm. .

Example 2 An ultrahigh molecular weight polyethylene powder (average particle size 120 μm) having a viscosity average molecular weight of 4.5 million was filled in a mold and heated at a temperature slightly lower than the melting point of the ultrahigh molecular weight polyethylene for 6 hours, and this filling was performed. The powder was pressed to adjust the density, then sintered and then cooled at room temperature to obtain a round rod porous body. This is cut to obtain an ultra high molecular weight polyethylene porous sheet having a thickness of 7 mm, a water pressure resistance of 12 KPa, a breathable Frazier 0.2, a porosity of 28%, and an average pore diameter of 30 μm.
I punched it out and made a filter.

Example 3 An ultrahigh molecular weight polyethylene powder (average particle size 120 μm) having a viscosity average molecular weight of 4.5 million was filled in a mold and heated at a temperature slightly lower than the melting point of the ultrahigh molecular weight polyethylene for 6 hours, and this filling was performed. The powder was pressed to adjust the density, then sintered and then cooled at room temperature to obtain a round rod porous body. This was cut to obtain an ultrahigh molecular weight polyethylene porous sheet having a thickness of 3 mm, a water pressure resistance of 3 KPa, a breathable Fragile 3, a porosity of 30%, and an average pore diameter of 35 μm. In addition, the water pressure resistance is 150K
PTFE porous body of Pa (NTF102 manufactured by Nitto Denko Corporation)
6. An average pore diameter of 0.6 μm and a thickness of 25 μm were heat-laminated (breathable fragile of the laminate: 0.3) and punched to a diameter of 2.4 mm to form a filter.

Comparative Example 1 Ultra high molecular weight polyethylene powder (average particle size 120 μm) having a viscosity average molecular weight of 4.5 million was filled in a mold and heated at a temperature slightly lower than the melting point of the ultra high molecular weight polyethylene for 6 hours, and this filling was performed. The powder was pressed to adjust the density, then sintered and then cooled at room temperature to obtain a round rod porous body. This was cut to obtain an ultra-high-molecular-weight polyethylene porous sheet having a thickness of 3 mm, a water pressure resistance of 3 KPa, a breathable Frazier 3.0, a porosity of 30%, and an average pore size of 35 μm. .

The above results are shown in Table 1.

[0044]

[Table 1] As shown in the results of Table 1, the chip filters of Examples have sufficient overflow prevention effect, and in particular, Example 3 using the laminate has sufficient air permeability. On the other hand, the chip filter of Comparative Example 1 had a low water pressure resistance, and therefore a sufficient overflow preventing effect was not obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a usage state of a chip loaded with a filter for a chip of the present invention.

[Explanation of symbols]

3 chip body 6 Chip filter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Wano             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. F term (reference) 2G052 AA29 AD06 CA18 CA23 EA01                       JA13 JA15 JA16 JA23                 4D019 AA03 BA13 BB06 BB07 BB08                       BB10 BC20 CA03 CB04 CB06                       DA01                 4G057 AB11

Claims (3)

[Claims] 1. A filter for a chip including a porous layer having a water pressure resistance of 4 KPa or more. 2. The breathable fragile is 0.1 to 20 cc /.
The filter for a chip according to claim 1, wherein the filter is cm ² · sec. 3. A chip in which a chip body is loaded with the filter for a chip according to claim 1 or 2.