CA1144393A - Test device - Google Patents
Test deviceInfo
- Publication number
- CA1144393A CA1144393A CA000399710A CA399710A CA1144393A CA 1144393 A CA1144393 A CA 1144393A CA 000399710 A CA000399710 A CA 000399710A CA 399710 A CA399710 A CA 399710A CA 1144393 A CA1144393 A CA 1144393A
- Authority
- CA
- Canada
- Prior art keywords
- membrane
- members
- liquid
- open position
- sorbent material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT OF THE DISCLOSURE
A test device for filtering liquid samples is described.
The device comprises telescoping top and bottom members defining a liquid reservoir therebetween, resilient means for biasing the members in the open position, one or more test wells in the top member with bottom openings covered with microporous memberanes, a coreactant immobilized on the membrane surfaces, and sorbent means between the members spaced from the membrane(s) in the open position but in contact therewith in the closed position. Liquids are passed through the membrane(s) into the sorbent means by depressing the members to the closed position.
A test device for filtering liquid samples is described.
The device comprises telescoping top and bottom members defining a liquid reservoir therebetween, resilient means for biasing the members in the open position, one or more test wells in the top member with bottom openings covered with microporous memberanes, a coreactant immobilized on the membrane surfaces, and sorbent means between the members spaced from the membrane(s) in the open position but in contact therewith in the closed position. Liquids are passed through the membrane(s) into the sorbent means by depressing the members to the closed position.
Description
~144393 1 This application is a division of Canadian Patent Application Serial No. 352,530 filed May 22, 19~0.
This invention relates to fluid filtering devices, and more particularly to filtering devices for filtering biological fluids or the like.
It is the principal object of the present invention to provide a simple and convenient device for filtering liquid samples. Further objects include provision of filtering devices which are portable, substantially self-contained, operable at room temperature, and in which a membrane is mounted for ease and rapidity of exposure to sample, incubation and washing. Other and additional objects and advantages will be apparent from the following description.
SUMMARY OF THE INVENTION
The present invention provides a device for filtering liquid samples such as biological fluids. The device comprises telescoping top and base members defining therebetween a liquid reservoir, the top member having one or more test wells each having a bottom opening to the periphery of which a microporous membrane is sealed, the membrane having fluid passages therethrough and having a coreactant immobilized to its internal and external surfaces, resilient means biasing the members in the open position, and sorbent material in the reservoir between the members having an upper surface spaced from the membrane(s) in the open position and adapted to contact the membrane(s) in the depressed position. The liquid capacity of the sorbent material should be sufficient to absorb by blotting or capillary action all the liquids to be passed through the wells. Preferably, a plurality of wells are provided sufficient for several filtra-tions, including positive and negative controls, and the sorbent - 1 - ~
~44~3 1 material has an upper surface layer which is not wetted by the liquids passing through the wells to minimize re-wetting the membranes with previously used liquids.
In use, the liquid sample to be filtered is placed in a well, preferably covering the upper surface of the membrane, the membrane and sample are incubated for a time sufficient for reaction to occur between the sample reagent, if any, and the membrane co-reactant, and the top member is then depressed to pass the sample through the membrane into the sorbent material.
The membrane may be washed to remove unreacted materials by relaxing the top member, placing wash liquid in the test well, and again depressing the top member to pass the wash liquid through the mem~rane into the sorbent material, repeating the washing steps, if desired.
DESCRIPTION OF PREFERRED EMBODIMENTS
-The preferred embodiment of the present invention is shown in the accompanying drawing in which:
Figure 1 is a top view of the test device;
Figure 2 is a bottom view;
Figure 3 is a side view; ana Figure 4 is an exploded section on the line 4-4 of Figure 1.
Referring to the drawing, the test device comprises a top member 10 telescoping with a base member 12 and defining therebetween a liquid reservoir 14, resilient means 16 such as resilient polyurethane foam or the like biasing members 10, 12 in the open position, and a sorbent material 18 in the reservoir 14.
Top member 10 is provided with a plurality of test wells 20, twenty-five as illustrated, each of which has a bottom ~4~393 1 opening covered by a microporous membrane 22 sealed liquid-tight to the circumference or periphery of the opening. Con~eniently the top member is designed for molding of plastic such as poly-styrene and the membranes can be sealed by any of a variety of known techniques, including heat sealing, solvent bonding to soften the styrene or by an adhesive. The top member 10 has a depending circumferential wall 24 provided with a plurality of small integral detents 26 at its lower margin adapted to snap over the outer edge of base member 12 to aid in retaining the members in assembled relation. If desired, detents 26 may be omitted, frictional fit and proper sizing of resilient foam 16 normally being sufficient to avoid disassembly in use.
Top member 10 is provided with air passage means such as a small hole 28 for expulsion and admission of air when the members are depressed and released to vary the volume of reser-voir 14. Such means can be provided at any convenient location in or between the members and may be omitted, if desired, especially if the fit between the members is relatively loose.
A snug fit with air passage means is preferred, however.
The membranes 22 are preferably of biologically inert materials and are thin and microporous, i.e., they have a multiplicity of interconnected pores of a size between about 25 nanometers and 25 micrometers, the pores occupying from about 60% to 80% of the membrane volume. Such membranes are well known and readily available in commerce. They have immobilized to their internal and external surfaces a co-reactant for the reagent to be assayed in the test liquid samples. Such mem-branes with various biologically active materials immobilized thereto are disclosed in the previously cited U.S. patent No. 4,066,512. Any other suitable co-reactant may be used and may be immobilized to the membrane in any suitable manner, ~.~g4393 1 including adhesion, cohesion, absorption, polymerization or the like.
Base member 12 comprises a depending por~ion 30 and an upper U-shaped circumferential lip 32 adapted to frictionally receive foam 16 which projects therefrom in position to contact the inside top portion 34 of member 10 when the members are squeezed or depressed from their open to their closed position.
Sorbent material læ is located in base member portion 30 and comprises a surface layer 36 and a bulk portion 38. Surface tO layer 36 is of a material which is substantially non-wetted by the liquids to be employed while bulk layer 38 is preferably wettable. For the normal aqueous liquids, top layer 36 may be of hydrophobic, porous non-woven rayon, for example grade 6212, 5 mils in thickness, 17.5 grams per square yard, of the Kendall Company, a material believed to be employed as the inner lining in disposable diapers. Bulk layer 38 is preferably an absorbent padding, for example, number 103 white saturating paper of the Hollingsworth and Vose Company. Sufficient thickness of material for layer 38 should be used to absorb all the liquids to be passed through the wells.
The above described device can be used to test a variety of liquids and reagent components by any suitable specific reaction procedure, for example chemical, immunochemical, enzy-matic, catalytic, chromotographic or the like, in which cne reagent may belin the test liquid and the other co-reactant immobilized or fixed to the mernbrane and at least one product of reaction retained in or on the membrane. The device is especially useful in immunochemical assays. As applied to assay of blood serum for antibodies to the antigens of Toxoplasma gondii, the following procedures may be employed.
1 Test devices having Toxoplasma antigens immobilized therein may be provided. Other inert binder proteins such as dried bovine serum albumin can be used. Add 0.05 ml of test serum diluted 1:6 with Tris-saline buffer, pH 7.8 to 8.2, to one test well and a like quantity of positive and negative control to adjacent tèst wells to cover the membranes. Incubate at room temperature (20-30C) for ten minutes and depress the cassette to pass the samples through the membranes into the sorbent material. Release when the membranes appear dry and fill the wells (0.8 ml) with aqueous Tris-saline wash buffer. Depress the cassette until the membranes appear dry and release. Care-fully pipette 0.1 ml of enzyme-linked antibody, goat anti-human immunoglobulin linked with horseradish peroxidase into each well to cover the membranes. Incubate for 15 minutes at room temperature. Depress the cassette until the membranes appear dry.
Again wash with Tri-saline solution. Add 0.05 ml of substrate-chromogen stain solution, incubate for 5 minutes, and compare any color change present with the-positive and negative controls.
The stain solution may comprise in water 0.3 mg/ml 4-aminoanti-pyrine, 20 mg/ml sodium hydroxybenzoate, 16.6 mg/ml potassium phosphate, monobasic, and 34.8 mg/ml potassium phosphate, dibasic. Color development of the test well similar to the negative control is negative; similar to positive control is positive, and intermediate color, indeterminate, requiring other or additional tests.
It should be noted that the test requires only about 30 minutes, compared to hours for prior procedures, and no special laboratory equipment is required. The test may be performed at any suitable location in a laboratory or in a field.
All materials and equipment may be conveniently packaged as a kit ~144393 1 and used without special training or skill. In the absence of sorbent material and means for bringing it into contact with the lower surface of the membranes, it has been found that gravity alone is insufficient to cause the liquids to pass through the membranes. While useable in any convenient size, the test device of this invention is best adopted for testing small liquid quantities, preferably less than 10 ml r and most preferable less than one ml. Membrane filters about 10 mm diameter.
Millipore Type SS, are preferred.
In addition to tests for antibodies to antigens of Toxoplasma gondii, the device may have immobilized to the membrane an antibody to Hepatitis B virus, an antibody or antigen to Entomeba histolytice, Rubella antigen,nucleic acids, or human antiglobulins to test respectively for the corresponding antigens or antibodies or for measuring levels or types of globulins in serum. The device can also be used for general filtration, omitting the immobilized co-reactant.
It should be understood that the foregoing description is for the purpose of illustration and that the invention in-cludes modifications and e~uivalents within the scope of theappended claims.
This invention relates to fluid filtering devices, and more particularly to filtering devices for filtering biological fluids or the like.
It is the principal object of the present invention to provide a simple and convenient device for filtering liquid samples. Further objects include provision of filtering devices which are portable, substantially self-contained, operable at room temperature, and in which a membrane is mounted for ease and rapidity of exposure to sample, incubation and washing. Other and additional objects and advantages will be apparent from the following description.
SUMMARY OF THE INVENTION
The present invention provides a device for filtering liquid samples such as biological fluids. The device comprises telescoping top and base members defining therebetween a liquid reservoir, the top member having one or more test wells each having a bottom opening to the periphery of which a microporous membrane is sealed, the membrane having fluid passages therethrough and having a coreactant immobilized to its internal and external surfaces, resilient means biasing the members in the open position, and sorbent material in the reservoir between the members having an upper surface spaced from the membrane(s) in the open position and adapted to contact the membrane(s) in the depressed position. The liquid capacity of the sorbent material should be sufficient to absorb by blotting or capillary action all the liquids to be passed through the wells. Preferably, a plurality of wells are provided sufficient for several filtra-tions, including positive and negative controls, and the sorbent - 1 - ~
~44~3 1 material has an upper surface layer which is not wetted by the liquids passing through the wells to minimize re-wetting the membranes with previously used liquids.
In use, the liquid sample to be filtered is placed in a well, preferably covering the upper surface of the membrane, the membrane and sample are incubated for a time sufficient for reaction to occur between the sample reagent, if any, and the membrane co-reactant, and the top member is then depressed to pass the sample through the membrane into the sorbent material.
The membrane may be washed to remove unreacted materials by relaxing the top member, placing wash liquid in the test well, and again depressing the top member to pass the wash liquid through the mem~rane into the sorbent material, repeating the washing steps, if desired.
DESCRIPTION OF PREFERRED EMBODIMENTS
-The preferred embodiment of the present invention is shown in the accompanying drawing in which:
Figure 1 is a top view of the test device;
Figure 2 is a bottom view;
Figure 3 is a side view; ana Figure 4 is an exploded section on the line 4-4 of Figure 1.
Referring to the drawing, the test device comprises a top member 10 telescoping with a base member 12 and defining therebetween a liquid reservoir 14, resilient means 16 such as resilient polyurethane foam or the like biasing members 10, 12 in the open position, and a sorbent material 18 in the reservoir 14.
Top member 10 is provided with a plurality of test wells 20, twenty-five as illustrated, each of which has a bottom ~4~393 1 opening covered by a microporous membrane 22 sealed liquid-tight to the circumference or periphery of the opening. Con~eniently the top member is designed for molding of plastic such as poly-styrene and the membranes can be sealed by any of a variety of known techniques, including heat sealing, solvent bonding to soften the styrene or by an adhesive. The top member 10 has a depending circumferential wall 24 provided with a plurality of small integral detents 26 at its lower margin adapted to snap over the outer edge of base member 12 to aid in retaining the members in assembled relation. If desired, detents 26 may be omitted, frictional fit and proper sizing of resilient foam 16 normally being sufficient to avoid disassembly in use.
Top member 10 is provided with air passage means such as a small hole 28 for expulsion and admission of air when the members are depressed and released to vary the volume of reser-voir 14. Such means can be provided at any convenient location in or between the members and may be omitted, if desired, especially if the fit between the members is relatively loose.
A snug fit with air passage means is preferred, however.
The membranes 22 are preferably of biologically inert materials and are thin and microporous, i.e., they have a multiplicity of interconnected pores of a size between about 25 nanometers and 25 micrometers, the pores occupying from about 60% to 80% of the membrane volume. Such membranes are well known and readily available in commerce. They have immobilized to their internal and external surfaces a co-reactant for the reagent to be assayed in the test liquid samples. Such mem-branes with various biologically active materials immobilized thereto are disclosed in the previously cited U.S. patent No. 4,066,512. Any other suitable co-reactant may be used and may be immobilized to the membrane in any suitable manner, ~.~g4393 1 including adhesion, cohesion, absorption, polymerization or the like.
Base member 12 comprises a depending por~ion 30 and an upper U-shaped circumferential lip 32 adapted to frictionally receive foam 16 which projects therefrom in position to contact the inside top portion 34 of member 10 when the members are squeezed or depressed from their open to their closed position.
Sorbent material læ is located in base member portion 30 and comprises a surface layer 36 and a bulk portion 38. Surface tO layer 36 is of a material which is substantially non-wetted by the liquids to be employed while bulk layer 38 is preferably wettable. For the normal aqueous liquids, top layer 36 may be of hydrophobic, porous non-woven rayon, for example grade 6212, 5 mils in thickness, 17.5 grams per square yard, of the Kendall Company, a material believed to be employed as the inner lining in disposable diapers. Bulk layer 38 is preferably an absorbent padding, for example, number 103 white saturating paper of the Hollingsworth and Vose Company. Sufficient thickness of material for layer 38 should be used to absorb all the liquids to be passed through the wells.
The above described device can be used to test a variety of liquids and reagent components by any suitable specific reaction procedure, for example chemical, immunochemical, enzy-matic, catalytic, chromotographic or the like, in which cne reagent may belin the test liquid and the other co-reactant immobilized or fixed to the mernbrane and at least one product of reaction retained in or on the membrane. The device is especially useful in immunochemical assays. As applied to assay of blood serum for antibodies to the antigens of Toxoplasma gondii, the following procedures may be employed.
1 Test devices having Toxoplasma antigens immobilized therein may be provided. Other inert binder proteins such as dried bovine serum albumin can be used. Add 0.05 ml of test serum diluted 1:6 with Tris-saline buffer, pH 7.8 to 8.2, to one test well and a like quantity of positive and negative control to adjacent tèst wells to cover the membranes. Incubate at room temperature (20-30C) for ten minutes and depress the cassette to pass the samples through the membranes into the sorbent material. Release when the membranes appear dry and fill the wells (0.8 ml) with aqueous Tris-saline wash buffer. Depress the cassette until the membranes appear dry and release. Care-fully pipette 0.1 ml of enzyme-linked antibody, goat anti-human immunoglobulin linked with horseradish peroxidase into each well to cover the membranes. Incubate for 15 minutes at room temperature. Depress the cassette until the membranes appear dry.
Again wash with Tri-saline solution. Add 0.05 ml of substrate-chromogen stain solution, incubate for 5 minutes, and compare any color change present with the-positive and negative controls.
The stain solution may comprise in water 0.3 mg/ml 4-aminoanti-pyrine, 20 mg/ml sodium hydroxybenzoate, 16.6 mg/ml potassium phosphate, monobasic, and 34.8 mg/ml potassium phosphate, dibasic. Color development of the test well similar to the negative control is negative; similar to positive control is positive, and intermediate color, indeterminate, requiring other or additional tests.
It should be noted that the test requires only about 30 minutes, compared to hours for prior procedures, and no special laboratory equipment is required. The test may be performed at any suitable location in a laboratory or in a field.
All materials and equipment may be conveniently packaged as a kit ~144393 1 and used without special training or skill. In the absence of sorbent material and means for bringing it into contact with the lower surface of the membranes, it has been found that gravity alone is insufficient to cause the liquids to pass through the membranes. While useable in any convenient size, the test device of this invention is best adopted for testing small liquid quantities, preferably less than 10 ml r and most preferable less than one ml. Membrane filters about 10 mm diameter.
Millipore Type SS, are preferred.
In addition to tests for antibodies to antigens of Toxoplasma gondii, the device may have immobilized to the membrane an antibody to Hepatitis B virus, an antibody or antigen to Entomeba histolytice, Rubella antigen,nucleic acids, or human antiglobulins to test respectively for the corresponding antigens or antibodies or for measuring levels or types of globulins in serum. The device can also be used for general filtration, omitting the immobilized co-reactant.
It should be understood that the foregoing description is for the purpose of illustration and that the invention in-cludes modifications and e~uivalents within the scope of theappended claims.
Claims (2)
1. A device for filtering a liquid sample comprising top and bottom members disposed for relative movement toward and away from each other to define an open position and a closed position, means for biasing the members in the open position, at least one well for the liquid sample in the top member, said well having an open bottom, a microporous membrane sealed liquid-tight to the periphery of and extending substantially horizontally across the open bottom of the well, said membrane having substantially uniform pores between about 25 nanometers and 25 micrometers in size, and sorbent material carried by said bottom member, the major portion of said material being wettable by said liquid, the upper surface of the sorbent material being disposed for contact with the bottom of said membrane when the members are in the closed position but being removed therefrom in said open position.
2. A device according to claim 1 wherein said sorbent material comprises a porous top layer which is substantially non-wettable by the liquid and a lower bulk layer which is wettable by said liquid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000399710A CA1144393A (en) | 1980-05-22 | 1982-03-29 | Test device |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000352530A CA1135530A (en) | 1980-05-22 | 1980-05-22 | Assaying a test liquid for the presence of a predetermined reagent |
| CA000399710A CA1144393A (en) | 1980-05-22 | 1982-03-29 | Test device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1144393A true CA1144393A (en) | 1983-04-12 |
Family
ID=25669083
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000399710A Expired CA1144393A (en) | 1980-05-22 | 1982-03-29 | Test device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1144393A (en) |
-
1982
- 1982-03-29 CA CA000399710A patent/CA1144393A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |