JP4315366B2 - Chip filter and chip - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tip filter applied to a tip used as a suction nozzle of a liquid suction device, for example, a pipette or attached to a tip portion of the nozzle, and a tip to which the tip filter is attached and applied.
[0002]
[Prior art]
Conventionally, when a reagent such as a reagent, body fluid (blood, etc.) or urine is dispensed and inspected, a tip is attached to the tip of a suction nozzle of a liquid suction device or the like, and a predetermined amount of the sample is sucked into the tip And dispense from the pool into another container. This dispensing operation is performed by either a manual or automatic method. In particular, a rapid and reliable dispensing operation is demanded today in the progress of automation and unmanned laboratory medicine.
[0003]
In the dispensing operation, the tip of the suction nozzle prevents contamination with different reagents and reagents, and the suction device itself is contaminated by the passage of suction droplets (steam), or from the suction device contaminated with liquid. A filter is attached to the chip for the purpose of preventing splash (steam) from entering back.
[0004]
As the filter, a polypropylene fiber bundle, a polyethylene terephthalate fiber bundle filter or a foamed urethane filter is generally used. Further, as an improvement of these filters, a porous sintered resin filter and a composite filter in which a porous resin sintered body and a nonwoven fabric are laminated are known (Patent Document 1).
[0005]
When a filter formed in a cylindrical shape is attached to a chip, a device is often used in which the filter is inserted through a parts feeder from a hopper so as to be easily inserted into the chip. In this case, the chip is aligned by vibration, and if necessary, the operation of determining the direction of the filter by auxiliary air injection or the operation of sending it to the chip and mounting it are performed.
[0006]
[Patent Document 1]
JP, 2001-121005, A [Problems to be solved by the invention]
However, when the porous sintered resin filter disclosed in Patent Document 1 is put in the parts feeder, when vibration is applied to align the filters, or when the filters are aligned by auxiliary air injection, The dynamic contact between the filter and the dynamic contact between the filter and the parts feeder component causes a static charge on the filter, resulting in a problem that the filter or the chip itself sticks out, the whiskers, foreign matter and the like are electrostatically adsorbed. Further, due to this electrification, there is a problem that the filter cannot be aligned and is mounted in a direction different from that of a normal product, or the mounting is lost, causing many troubles leading to the stop of the manufacturing apparatus.
[0007]
Not only the environment of the filter mounting process at the time of chip manufacture described above, but also the usage environment is not necessarily in the clean room. For example, in extreme cases, it can be used in developing countries in arid areas. Under such conditions of use, the filter described in Patent Document 1 is likely to adsorb dust and dust in the air with static electricity, and biological dust that is usually the source of RNA and DNA is present in the dust. Because of the presence, it was difficult to avoid the problem of affecting the measurement.
[0008]
In particular, filters made of materials with low polarity, such as UHMWPE and HDPE, which are the filter materials described in Patent Document 1 and easily charged with static electricity, are long enough to measure the charge half-life once charged, and are attached to the chip. However, it may remain charged. When such a charge remains, there may be an effect on measurement accuracy due to the adsorption of dust during use.
[0009]
The object of the present invention is to prevent troubles caused by foreign matter such as flash, dust, debris, whiskers, etc. in the production process of filters and chips, or stop the production equipment due to misalignment of the filter, and dust in the air during use. It is an object of the present invention to provide a chip filter and a chip that do not affect the measurement accuracy due to adsorption.
[0010]
Another object of the present invention is to provide a chip filter and a chip excellent in the effect of preventing the accuracy of injection amount from being lowered due to a light over-suction overflow or the like when dispensing a small amount of liquid.
[0011]
[Means for Solving the Problems]
That is, the chip filter of the present invention is a porous resin filter whose surface is antistatic treated.
[0012]
Antistatic treatment has the effect of preventing trouble that leads to stop of production equipment due to adhesion of foreign matters such as burrs, dust, debris, whiskers etc. to the filter or filter misalignment in the filter and chip manufacturing process due to static electricity generation, It has become possible to obtain a chip filter that does not affect the measurement accuracy due to the adsorption of dust in the air during use.
[0013]
In the above filter for a chip, it is preferable that the surface is further subjected to water repellent treatment.
[0014]
Since the antistatic treatment in the above-described invention is usually a hydrophilic treatment using surface activity or the like, hydrophilicity is imparted to the entire filter only by such a charging treatment. As a result, the water pressure resistance of the filter is reduced, and the effect of preventing the overflow of the dispensed liquid may be reduced. A filter having both water repellency and antistatic property was obtained by subjecting the antistatic treated filter to further water repellency treatment.
[0015]
Such a filter has a water-repellent effect, and thus has an increased water pressure resistance and can prevent an overflow of the dispensing liquid of the filter. In addition, since the filter is not wettable, even if it overflows, even if the pipette is pushed and discharged to recover the liquid, the liquid is hardly contaminated. Furthermore, the water-repellent effect also has the effect of preventing adhesion of dust containing biological residues that are the basis of sand dust, RNA, and DNA.
[0016]
The chip of the present invention is characterized in that the chip filter according to claim 1 or 2 is mounted.
[0017]
Such a chip has few troubles that lead to the stop of the manufacturing equipment due to the prevention of foreign matter such as flash, dust, debris, whiskers, etc. in the manufacturing process and the misalignment of the filter, etc., and measurement by adsorption of dust in the air during use The accuracy is not affected.
[0018]
Furthermore, the tip is excellent in the effect of preventing the accuracy of injection from being lowered due to a light over-suction overflow or the like when dispensing a small amount of liquid.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The filter of the present invention is composed of a porous resin having a compression modulus of 100 to 1000 kg / cm ² , preferably 200 to 400 kg / cm ² , and the average pore diameter of the porous resin is 10 to 100 μm, preferably 20 to 40 μm. It is preferable. The air permeability (Fragile method) is 0.5 to ²⁰ cm ³ / cm ² · s, preferably 1 to 5 cm ³ / cm ² · s.
[0020]
The resin constituting the filter is not particularly limited, but it has excellent solvent resistance, acid resistance, alkali resistance, hygiene, dust-free, radiation resistance, autoclave resistance, rigidity, breathability, etc. It is preferably a sintered porous body of resin particles selected from polyolefins and fluororesins, and as polyolefins, it is preferable to use ultrahigh molecular weight polyolefins such as ultrahigh molecular weight PE and ultrahigh molecular weight PP. Fluorine resins include polytetrafluoroethylene (PTFE), polytetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene / hexafluoropropylene copolymer (FEP), etc. preferable. These resins may be used in combination of two or more as required. For example, ultra high molecular weight polyethylene is polyethylene having a viscosity average molecular weight of 500,000 to 10,000,000, preferably 1,000,000 to 7,000,000. As ultra-high molecular weight polyethylene, commercially available products such as Hi-Zex Million (Mitsui Chemicals), Hostalene GUR (Tycona) can be used.
[0021]
In the production of an ultra-high molecular weight porous sintered filter having a compression elastic modulus of 200 to 400 kg / cm ² and an average pore diameter of 20 to 40 μm and air permeability (Fragile method) of 1 to ⁵ cm ³ / cm ² · s, a known porous resin is used. The manufacturing method can be used without limitation. As a method for producing such an ultra high molecular weight porous sintered filter, for example, the production method described in Japanese Patent No. 2020026 can be exemplified. In the case of the sintering method, the compression modulus and average pore diameter in the obtained porous sheet can be controlled by the average particle diameter of the powder. In the present invention, a powder having an average particle size of 25 to 170 μm, more preferably an average particle size of 100 to 170 μm is used.
[0022]
As the antistatic agent for treating the porous resin filter, known antistatic agents can be used without limitation, and cationic antistatic agents, anionic antistatic agents, and nonionic antistatic agents are exemplified. These antistatic agents may be either water-based or solvent-based. Commercially available antistatic agents can be used, for example, Elecnon OR-W (New Fine Chemical) as a cationic antistatic agent, Electro Stripper F (Kao) as an anionic antistatic agent, and Nonionic antistatic agent. Is exemplified by Emulgen 109P (Kao).
[0023]
In the present invention, as the water-repellent treatment agent for treating the porous resin, a known water-repellent treatment agent can be used without limitation, and examples thereof include a fluorine-based water-repellent treatment agent and a silicon-based water-repellent treatment agent. Commercially available products can be used as the water-repellent treatment agent. For example, TG-500 (Daikin Industries) is exemplified as the fluorine-based water-repellent treatment agent, and KM740 (Shin-Etsu Chemical) is exemplified as the silicon-based water-repellent treatment agent. .
[0024]
The shape of the filter made of porous resin in the present invention may be any shape that can be mounted without a space inside the chip having a circular cross section, and may be molded simultaneously with sintering using a mold, or in a sheet or block shape. After being sintered, it may be formed by performing cutting, punching, cutting or the like. Examples of the shape include a spherical shape, a truncated cone shape, and a cylindrical shape. The shape of the filter is preferably a columnar shape having a thickness of 0.5 to 5 mm. The thickness of the cylinder is generally from 0.5 to 5 mm, in particular from 2 to 5 mm, but can also be greater than 5 mm. A filter formed by punching from a porous resin sheet manufactured by a sintering method has a compression elasticity that allows it to be pressed into the inside of the chip tube without gaps, and has the advantage of excellent dust-free properties that do not contain dust. is doing.
[0025]
It is also a suitable aspect that the filter increases the cross-linking density by electron beam irradiation for the purpose of improving heat resistance and the like.
[0026]
The antistatic treatment and the water repellent treatment are performed by utilizing the penetrability due to the capillary action of the liquid. These treatments are performed on the entire surface of the resin constituting the porous resin. When the filter is formed from a porous resin sheet by punching or the like, the filter may be formed in a sheet state or after processing into a predetermined filter shape.
[0027]
An example of a chip equipped with the filter of the present invention is shown in FIG. The tip 3 is composed of a straight tube portion that is attached to the mouth tube portion 2 of the nozzle of the suction device and a tapered portion that narrows toward the opening. The tip filter 6 is a thick portion of the tapered portion of the tip 3. It is attached to the diameter part. The tip 3 generally has a tapered shape (spoid shape) or a shape composed of a tapered portion and a straight tube portion. The chip 3 can be manufactured by injection molding of a resin excellent in solvent resistance, acid resistance, alkali resistance, hygiene, dustlessness, radiation resistance, autoclave resistance, mechanical strength, etc., for example, polycarbonate. In addition, polyolefin resins such as polypropylene can be used as general-purpose chips.
[0028]
In order to dispense a test solution or a reagent using a chip equipped with the chip filter 6 of the present invention, as shown in FIG. 1, the chip body 3 is mounted on the mouth tube portion 2 of the nozzle of the suction device. Then, 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 exhibits the effect of preventing the passage of the aerosol 4 which is a droplet of the test solution 5 and preventing the overflow of the test solution 5 at the time of excessive suction.
[0029]
As shown in FIG. 1, the shape of the filter for a chip is a shape corresponding to the shape of the inner peripheral surface of the chip body 3, but a columnar shape is generally used as described above. The filter 6 is slightly deformed by being attached (inserted) to the chip body 3 and is fixed to the inner peripheral surface of the chip body 3 by an elastic restoring force at that time.
[0030]
【Example】
Examples that specifically show the structure and effects of the present invention will be described below.
Example 1
Using ultra high molecular weight polyethylene having a viscosity average molecular weight of about 4 million, a thickness of 3.5 mm formed by a sintering method, a compression elastic modulus of 250 kg / cm ² , and an air permeability (Fragile method) of 1.5 cm ³ / cm After impregnating a porous sheet with ² · s, a porosity of 30%, and an average pore diameter of 35 μm with a pure aqueous solution of a cationic antistatic agent Elecnon OR-W (New Fine Chemical) having a solid content concentration of 0.5%, and drying, 4. A filter a was punched into a 7 mmφ cylindrical shape. Using 5000 pieces of the filters a, a hopper type charging machine and a vibration type aligning machine were used for continuous mounting experiments on PP chips having the shape shown in FIG.
[0031]
(Example 2)
After impregnating the ultra-high molecular weight polyethylene porous sheet used in Example 1 with a pure aqueous solution of a cationic antistatic agent Elecnon OR-W (New Fine Chemical) having a solid content concentration of 0.5% and drying it. A filter was punched into a 4.7 mmφ cylindrical shape. This filter was further impregnated with a liquid having a solid content concentration of 0.5% of a fluorine-based water repellent TG-500 (Daikin Industries) and dried to obtain a filter b. Using 5000 pieces of the filters b, an experiment was carried out for continuous mounting on PP chips using a hopper type charging machine and a vibration type aligning machine.
[0032]
(Comparative Example 1)
The ultra-high molecular weight polyethylene porous sheet used in Example 1 was subjected to static elimination only with an electrostatic blower without antistatic treatment to obtain a filter c. Using 5000 pieces of the filter c, an experiment was made of continuous attachment to a PP chip using a hopper type charging machine and a vibration type aligning machine.
[0033]
<Evaluation test>
1) It was visually confirmed whether the filters a to c were attached to the chip without mistakes. (Evaluation of poor mounting due to static electricity)
In addition, it was confirmed whether there was a machine stop due to poor filter feed or mounting.
[0034]
2) It was confirmed by visual observation that no dust or foreign matter had adhered to the filter chip mounted without mistake. (Evaluation of adhesion failure due to static electricity)
<Evaluation results>
(Evaluation of poor mounting due to static electricity)
In Examples 1 and 2, when the number of filters a and b was set to 5,000, the embedded device stopped only once. On the other hand, in the comparative example, the built-in machine stopped several times, and the evaluation was impossible.
[0035]
Regarding the filter mounting, there was no mounting error for the filters a and b of the example, but the filter c of the comparative example could not be evaluated because the machine stopped several times.
[0036]
(Evaluation of adhesion failure due to static electricity)
In the chips of Examples 1 and 2, no adhesion of dust and foreign matters was confirmed visually. Many chips with burrs were seen after the filter c of the comparative example was mounted.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state in which a chip equipped with a chip filter is mounted on a mouth tube portion of a nozzle of a suction device

Claims (3)

Filter for chip made of porous sintered resin whose surface is antistatic treated.   The chip filter according to claim 1, wherein the surface is further water-repellent.   A chip equipped with the chip filter according to claim 1.

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