WO2004030721A2

WO2004030721A2 - Fluid collecting device, methods of production and uses thereof

Info

Publication number: WO2004030721A2
Application number: PCT/US2003/031225
Authority: WO
Inventors: Wayne A. Jensen; Kenneth W. Lee; Karen S. Sellins; Timothy Powell
Original assignee: Heska Corporation
Priority date: 2002-10-03
Filing date: 2003-10-02
Publication date: 2004-04-15
Also published as: AU2003279759A8; AU2003279759A1; WO2004030721A3

Abstract

The present invention relates to sample collection devices for collecting samples suspected of containing one or more target analytes. After collection, the sample is released from the device and tested for the target analyte. The invention further provides methods of producing the devices and methods of using the devices to collect samples. Kits containing the devices and associated components are also provided.

Description

FLUID COLLECTING DEVICE, METHODS OF PRODUCTION AND USES THEREOF

FIELD OF THE INVENTION

The present invention relates to devices useful for collecting fluids and in particular, bodily fluids that can then be subjected to further analysis. The present invention also relates to methods of producing such devices as well as methods of using such devices. BACKGROUND OF INVENTION

Many medical tests are based on measuring the levels of specific analytes in a sample of fluid obtained from the patient. However, there are times when obtaining a useable sample can be problematic. Urine samples are often collected by positioning a container in the urine stream, frequently after the process of voiding has begun so as to avoid any contaminants that may be present in the initial portion of the urine discharge. However, urine collected in this manner often results in a decidedly unpleasant experience for the person collecting the sample since urine frequently splashes about the hands and container during collection.

The problem of urine collection becomes even more difficult in the field of veterinary medicine. Animals, and in particular dogs and cats, are closer to the ground allowing less room in which to properly position a container to catch an adequate urine sample. In addition, animals do not necessarily indicate when the process of urination is about to begin with the result that a container must hastily be inserted into the urine stream hidden underneath the animal. Others have proposed addressing some of these problems by using a sponge to collect the urine sample, as described, for example, in U.S. Patent No. 4,014,322, issued March 29, 1977, entitled "Specimen Collecting Device and Method," and U.S. Patent No. 4,596,157, issued June 24, 1996, entitled "Device for Obtaining, Transporting and Using a Liquid Specimen.". However, depending on what is to be done with the collected urine, such devices may not be appropriate. For example, a common use for collected urine is to test for the presence of an analyte such as a sugar. Interaction of the urine sample with the sponge material disclosed in the above- mentioned patents may alter the results of the test to be performed. For example, analytes in the urine sample may bind to or otherwise be altered by the sponge material. Accordingly, the need exists for a device that can easily collect a sample from a patient in a way that does not alter the results of any tests or assays performed on the sample. The present invention satisfies this need and provides related advantages as well. SUMMARY OF THE INVENTION

The present invention relates to sample collection devices useful for collecting a sample suspected of containing one or more target analytes. The devices are composed of treated absorbent material that is capable of absorbing and releasing a sample without substantially altering the concentration of the target analyte in the sample. The released sample can then be analyzed or tested in an assay for one or more target analytes.

Useful absorbent materials include cellulose, poyethylene, polyurethane, polyester, paper and cotton. The absorbent material can be contacted with or exposed to a detergent, a buffer or a protein to reduce the risk of significantly altering the concentration of the target analyte in the sample. Suitable detergents include Tween- 20, Tween-80, octyl glucoside and ethylphenolpoly(ethylene-glycoether) ("NP-40"). The absorbent material can absorb at least twice its own weight in sample, preferably at least about 5 ml of sample per gram of absorbent material, and can release at least about 10% of the absorbed sample. After absorbing the sample, the absorbent material can expand in at least one dimension to at least 5 times greater than its dry state.

The sample collection devices of the invention preferably include at least one handle for collecting samples. The handle can be attached directly or indirectly to the absorbent material. The devices can also include other components, such as a housing or other structural support. Samples that can be collected with the devices of the present invention include bodily fluids, such as urine, blood, serum and saliva, and solubilized tissues. The target analyte contained in a sample can be any protein or other compound. For example, a target analyte can be albumin or a higher molecular weight protein, such as immunoglobulin . The present invention further provides methods of producing sample collection devices. The methods are generally accomplished by first contacting the absorbent material with a buffer, a detergent or a protein, followed by drying the absorbent material to produce the sample collection device. Prior to or simultaneously with the drying step, the absorbent material can be compressed if desired.

The invention also relates to methods of obtaining a sample for analysis in which the method includes absorbing the sample onto a sample collection device of the present invention and releasing a sufficient amount of the sample from the device to conduct a desired test.

In yet another embodiment of the invention, methods to detect or measure a target analyte in a sample are provided. The methods are accomplished by first absorbing a sample onto a device of the present invention, releasing the sample from the device, and then detecting or measuring the target analyte in the released sample. Kits containing the sample collection device are also provided. The kits can contain associated components useful for performing the methods of the present invention, including containers for holding the devices and tests for assaying the target analyte. DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to sample collection devices composed of absorbent material useful for the collection of various samples suspected of containing one or more target analytes. The devices allow for the collection of a sample than can then be released and thereafter tested for one or more target analytes without significantly altering the concentration of the target analyte(s) in the sample.

The device can be used to collect any sample suitable for further analysis or testing, such as a bodily fluid. As used herein, the terms "bodily fluid," "fluid sample," "fluid" and "sample" can be used interchangeably. Examples of suitable bodily fluids include, but are not limited to, urine, blood, serum, plasma, saliva and the like. Samples can also include tissues (e.g. homogenized tissues) suspected of containing a target analyte that have been put into solution to render then absorbable by the devices of the present invention. Although the samples can be collected directly or indirectly from a patient, the devices are particularly suited for the collection of bodily fluids directly from a patient. As used herein, the term "patient" refers to any animal from which a sample can be obtained, including, humans, dogs, cats, horses, farm animals, non- domesticated animals for instance. In addition, the term "patient" is not used to indicate the health or lack of health of the animal. The terms "target analyte" and "analyte" refer to any substance that can be detected in the sample. Suitable target analytes to be measured include, but are not limited to, proteins and/or protein fragments, polypeptides, sugars, salts, ions, lipids, crystals (in particular struvite and calcium oxalate crystals), casts (cell debris), blood cells, cells, bacteria, viruses, steroids, organic molecules, drug by-byproducts, metabolic byproducts and the like. For example, target analytes can be albumin and higher molecular weight proteins, such as immunoglobulin, that may be present in the urine of patients with renal disease, including early renal disease. In humans, albumin is a protein that has an approximate molecular weight of 66 kDa as determined by polyacrylamide gel (PAGe) electrophoresis. Canine albumin has an approximate molecular weight of 68 kDa, as determined by PAGe electrophoresis. Albumin may be present in urine as an intact protein or as fragments or peptides derived from the intact protein. Albumin in the urine is referred to as albuminuria. Microalbuminuria is the presence of albumin in a urine sample in a range from about 1 Oμg/ml to about 300μg/ml when the sample is normalized to a specific gravity of 1.010.

The devices of the present invention contain one or more absorbent materials that will not significantly alter the amount of target analyte in the sample from the time of collection to the release of the sample from the device. As used herein, the terms "concentration," "level," or "amount" and the like are used interchangeably. Methods of determining the concentration of an analyte in a fluid sample are known to those skilled in the art. As used herein, the terms "not significantly altered" and "without significantly altering" mean the concentration of a particular target analyte in a sample exposed to the absorbent material will differ by no more than about 50%, no more than about 40%, no more than about 30%, no more than about 20%, no more than about 15 %, no more than about 10% or no more than about 5%, no more than about 1% or no more than about 0% from the concentration of the same target analyte in a sample that has not been in contact with the absorbent material. Likewise, as used herein, the phrase "not significantly affect the results of a test" means a test the analyte concentration in a sample contacted with the absorbent material will differ from the concentration of the same target analyte in a sample not contacted with the absorbent material by no more than about 5%, no more than about 10%, no more than about 20%, no more than about 30%, no more than about 40% or no more than about 50%, when the target analyte concentrations are compared using the same test or assay designed to measure the amount of that particular target analyte.

The term "absorbent material" refers to any material that absorbs fluid and can be used to collect (i.e. absorb) a sample to be tested. Examples of such absorbent materials include, but are not limited to natural sponges, synthetic sponges, absorbent polymers, blotting papers, tissues, capillary tubes, swabs and the like. Further examples of such material include, but are not limited to, paper, cotton, glass wool, cellulose, polyethylene, polyurethane, polyester and acrylate polymers. Cellulose sponges are particularly useful for collecting urine. A device can be constructed of one type of absorbent material or a combination of absorbent materials.

As the device of the present invention is meant to be used to collect a fluid sample that is to be tested or assayed, the absorbent material or materials used in constructing a device of the present invention should be able to absorb a quantity of sample sufficient for one or more of the intended tests or assays. Methods for measuring and terms for describing the amount of fluid absorbed by the absorbent material are known to those skilled in the art. For example, the amount of fluid absorbed by the absorbent material can be measured as an absolute volume using units such as, for example, milliliters (ml) or ounces (oz). In one embodiment, the absorbent material is able to absorb between about 1 ml and 500 ml per gram of absorbent material. Accordingly, the absorbent material is able to absorb at least about 1 ml, at least about 2 ml, at least about 3 ml, at least about 4 ml, at least about 5 ml, at least about 6 ml, at least about 7 ml, at least about 8 ml, at least about 9 ml, at least about 10 ml, at least about 15 ml, at least about 20 ml, at least about 25 ml, at least about 50 ml, at least about 100 ml, at least about 250 ml or at least about 500 ml of fluid per gram of absorbent material. The amount of fluid sample absorbed by the absorbent material can also be quantified by its weight relative to the weight of the absorbent material. For example, if 1 gram (gm) of absorbent material is able to absorb 10 grams of fluid sample, then the absorbent material is said to be able to absorb 10 times (10X) its own weight in fluid sample. As such, the absorbent material should be able to absorb at least about IX, at least about 2X, at least about 3X, at least about 4X, at least about 5X, at least about 6X, at least about 7X, at least about 8X, at least about 9X, at least about 10X, at least about 1 IX, at least about 12X, at least about 13X, at least about 14X, at least about 15X, at least about 16X, at least about 17X, at least about 18X, at least about 19X, at least about 20X, at least about 25X, at least about 30X, at least about 40X,at least about 50X, at least about 100X, at least about 500X or at least about 1000X its own weight in fluid sample.

Appropriate absorbent materials should be able to release a sufficient amount of the sample from the device so the released sample can be used in one or more tests or assays. Therefore, the sample can be released into one or more aliquots for analysis or testing. Methods of releasing the sample from the absorbent material are known to those skilled in the art and include, but are not limited to, for example, extracting the sample by capillary action or squeezing the absorbent material to release the sample. Particularly suitable absorbent materials to use in constructing a device of the present invention are those that release at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%_Λat least about 80%_sat least about 90% or about 100% of the absorbed sample. It can be appreciated by those skilled in the art that the exact amount of sample released will depend on the amount of pressure applied to the absorbent material and the amount of sample needed to perform a desired test or tests. For example, the force applied can be generated by hand squeezing or can be equivalent to the squeezing force generated by the average human hand. Also contemplated is the use of mechanical devices to release the liquid from the absorbent material. For example, the absorbed fluid sample can be released from the absorbent material by applying a squeezing force to the absorbent material using a mechanical press. As a further example, the absorbent material can be passed through a narrow aperture resulting in the sample being squeezed from the absorbent material. A useful squeezing force ranges from about 1 Newton (N) to about 500 N. This force can also be between about 1 and about 112 pounds (lbs). The absorbent material can release a suitable amount of the absorbed sample when the absorbent material is subjected to a squeezing force equivalent to no more than about 1 Newton, no more than 2N, no more than 3N, no more than 4 N, no more than 5N, no more than ION, no more than 15N, no more than 20N, no more than 25N, no more than 30N, no more than 40N, no more than 50N, no more than 60 N, no more than 70N, no more than 80N, no more than 90N, no more than 100N, no more than 125N, no more than 150N, no more than 175N, no more than 200N, no more than 250N, no more than 300N, no more than 400N or no more than 500N. The devices of the present invention can optionally include other components, such as one or more handles. As used herein, the term "handle" refers to any part of the device that is used for gripping the device, wherein the gripping part is not involved in absorbing the fluid sample. A handle can be made of any material useful for gripping the collection device. Suitable materials include, but are not limited to, plastic, paper, metal, wood, synthetic composites or combinations thereof. A handle can be attached directly or indirectly to the absorbent material. Attachment of the handle, directly or indirectly, to the absorbent material can be accomplished using any suitable attachment means known to those skilled in the art. Other components can be included in the devices, such as a housing or other structural support to hold or protect the absorbent material and/or the collected sample. Those skilled in the art can readily determine the desirability or need for such additional components.

The present invention further provides methods for producing the sample collection devices described above. Such methods can be accomplished by:

(a) contacting the absorbent material with a buffer, a detergent or a protein;

(b) optionally compressing the absorbent material; and

(c) drying the absorbent material to produce the sample collection device. In constructing a device of the present invention, the absorbent material is treated to prevent the absorbent material from significantly altering the concentration of the target analyte(s) in the released sample. Such treatments may or may not alter the interaction of the fluid sample with the absorbent material. For example, the absorbent material can be treated in such a way as to inhibit the target analyte(s) in the fluid sample from binding to the absorbent material. As used herein, "to inhibit binding" means to prevent the binding of an analyte to the absorbent material to such a degree that contact of sample with the absorbent material does not significantly alter the concentration of the target analyte(s) nor affect the results of a test that measures the concentration of the analyte in the sample after the sample has been released from the absorbent material. Additionally, the absorbent material can be treated in such a way as to prevent one or more components of the absorbent material from "leaching" into the sample and affecting the concentration of the target analyte or results of a test that measures the presence, absence or concentration of the target analyte in the sample . The absorbent material is treated with an aqueous solution ("treatment solution") prior to collecting the sample of fluid to be tested. Treatment solutions can optionally contain one or more treatment agents. Examples of useful treatment agents with which to treat the absorbent material include, but are not limited to, protein, detergents, buffers, salts and the like. Examples of proteins useful for treating the absorbent material, include, but are not limited to, albumin, soy proteins, milk proteins and yeast proteins. Suitable detergents are known to those skilled in the art and include, but are not limited to, anionic detergents, cationic detergents, non-ionic detergents and zwitterionic detergents. Examples of useful detergents include, but are not limited to, cholic acid salts, N-lauroylsarcosine, polyethylene stearate, saponin, 3[3(Cholamidopropyl)dimethylammonio]-l-propanesulfonic acid (CHAPS), 3[3(Cholamidopropyl)dimethylammonio]2-hydroxy-l-propanesulfonic acid (CHAPSO), nonidet 40 (NP-40), polyoxyethylenesorbitan monolaurate (Tween 20), polyoxyethylenesorbitan monooleate (Tween 80), polyoxyethylenesorbitan monopalmitate (Tween 40), polyoxyethylenesorbitan monostearate (Tween 60), t- octylphenoxypolyethoxyethanol (Triton X-100), Triton X-114 and octyl glucoside. The absorbent material can be also be contacted (i.e. exposed) with a treatment solution of distilled water or one containing phosphate buffered saline (PBS). Those skilled in the art can readily determine an appropriate treatment for the absorbent material based on the choice of absorbent material, the sample to be collected and the test or analysis to be performed.

Contact of the absorbent material with the treatment solution can be in the range of about 1 minute to more than 24 hours. A particularly useful length of treatment time is at least about 1 minute, at least about 5 minutes, at least about 10 minutes, at least about 15 minutes, at least about 20 minutes, at least about 30 minutes, at least about 45 minutes, at least about 60 minutes, at least about 75 minutes, at least about 90 minutes, at least about 105 minutes, at least about 120 minutes, at least about 150 minutes, at least about 180 minutes, at least about 240 minutes or at least about 300 minutes. Also contemplated is contacting the absorbent material with the treatment solution for at least about 6 hours, at least about 8 hours, at least about 10 hours at least about 12 hours and about 24 hours.

The amount of treatment agent used can readily be determined by one of skill in the art and will depend on the type of agent, the type of absorbent material selected, the sample to be collected and the test or analysis to be performed. A commonly used method of determining the amount of a treatment agent in a solution is a ratio comparing the weight (w) of the agent to the volume (v) of the treatment solution. This w/v ratio is usually given as a percentage with 1 gram per 100 ml being equal to 1%. A suitable amount of agent to use is an about 0.001% solution, an about 0.005% solution, an about 0.01% solution, an about 0.025% solution, an about 0.05% solution, an about 0.075% solution, an about 0.1% solution, an about 0.25% solution, an about 0.5% solution, an about 0.75% solution, an about 1% solution, an about 1.5% solution, an about 2% solution and an about 5% solution. Further examples of useful amounts of treatment agents are disclosed in the Examples.

In making a device of the present invention, the treated absorbent material is preferably compressed. As used herein, the term "compressed" refers to a material that has been reduced in volume as a result of its being exposed to pressure in excess of the atmospheric pressure. As used herein, the term "volume" refers to the 3- dimensional space occupied by the material as measured in cubic units. A reduction in the volume of an absorbent material can be achieved, for example, by placing the material under pressure thereby reducing the size (i.e. width, length and/or height) of the material in one or more than one dimension without a compensatory increase in size in any or all of the other dimensions. Suitable absorbent materials are those that can be compressed so that their size is reduced, in at least one dimension, to at least about 75%, to at least about 50%, to at least about 40%, to at least about 30%, to at least about 20%, to at least about 10%, to at least about 5%, to at least about 2.5%, to at least about 1% of the original size. Similarly, suitable absorbent materials are those that can be compressed so that their volume is reduce to at least about to at least about 50%, to at least about 40%, to at least about 30%, to at least about 20%, to at least about 15%, to at least about 10%, to at least about 5%, to at least about 2.5%, to at least about 1% of the materials original volume. Suitable methods of compressing absorbent materials for constructing a device of the present invention are known to those skilled in the art and include, but are not limited to, mechanical presses including lever-operated presses and screw presses, hydraulic presses, bladder presses, clamps, hyperbaric chambers and the like.

It can be appreciated by those skilled in the art that when absorbent material is dried during or after compression, the absorbent material will often maintain the compressed volume, even after the material is returned to normal atmospheric pressure. In one embodiment, a device of the present invention comprises absorbent material that has been dried during or after compression so that the absorbent material maintains the compressed volume even at normal atmospheric pressure. As used herein, the terms "dried," "dehydrated" or "desiccated" and the like describe materials sufficiently devoid of moisture so that upon exposure to a liquid, the material is able to absorb from about IX to about 1000X its own dry weight in fluid sample as described previously. Methods of drying absorbent material to be used in constructing a device of the present invention are known to those skilled in the art and include, for example, air drying at room temperature, drying using heat generated by a heat source such as a gas or electric heater, drying using a desiccant and drying using a vacuum.

The drying and/or compression of the absorbent materials provide the means for the materials to expand during the process of absorbing a sample. As used herein, the terms "expand" or "swell" and the like refer to an increase in the volume of an absorbent material due to an increase in the size (i.e. width, length and/or height) of the material in one or more than one dimension. Suitable dried and/or compressed absorbent materials are those that, upon contact with a liquid, expand in at least one dimension to a size measuring at least about 2 times (2X), at least about 3X, at least about 4X, at least about 5X, at least about 6X, at least about 7X, at least about 8X, at least about 9X, at least about 10X, at least about 1 IX, at least about 12X, at least about 13X, at least about 14X, at least about 15X, at least about 20X, at least about 25X greater than its pre-exposure size. Particularly useful absorbent materials are those that, upon contact with a liquid, expand at least about 2X, at least about 3X, at least about 4X, at least about 5X, at least about 6X, at least about 7X, at least about 8X, at least about 9X, at least about 10X, at least about 1 IX, at least about 12X, at least about 13X, at least about 14X, at least about 15X, at least about 20X, at least about 25X, at least about 30X, at least about 40X, at least about 50X or at least about 100X in volume.

The methods for making the devices of the present invention can also include additional steps. For example, additional components, such as handles, housings and other structural components as described above can be added during the manufacture of such devices. The present invention further provides methods for obtaining a sample for analysis. The methods include the steps of:

(a) absorbing a sample onto a sample collection device of the present invention; and (b) releasing a sufficient amount of the sample from the device to conduct an analysis.

In accordance with the methods of this embodiment, the sample can be obtained directly or indirectly from a patient. Direct methods include collecting the sample directly from the patient onto the device, for example by placing the device in the urine stream while a patient is urinating or placing the device on a bleeding wound. Indirect methods include collecting or obtaining a sample by whatever means and thereafter absorbing the sample onto the sample collection device of the present invention. For example, a bodily fluid can be collected in a container, followed by dipping a sample collection device into the container or pouring the contents of the container onto the sample collection device. If desired, various samples can be mixed prior to being absorbed onto the device, such as the case of batch mixtures, when it is desirable to test the mixture for one or more target analytes.

After the sample is absorbed, the device can be used for storage of the sample until the sample is released for analysis. In addition, the device can be used to transport the sample safely to another location for analysis. After being released from the device, the sample can be analyzed for various components. As used herein, the term "analysis" refers to the identification of the various components within the sample or a specific test for one or more target analytes. The term "a sufficient amount" as used herein depends on the analysis to be performed and can readily be determined by those skilled in the art.

Methods of detecting or measuring one or more target analytes in a sample are also provided. Such methods are generally accomplished by:

(a) absorbing the sample onto the sample collection device;

(b) releasing the sample from the device; and (c) detecting or measuring the target analyte in the released sample.

In accordance with the methods of this embodiment, the collected and released sample can be subjected to testing for one or more target analytes. Such tests can detect and/or measure (i.e. quantitate or semi-quantitate) the target analyte(s). Those skilled in the art can readily determine the appropriate tests and test formats, including immunoassays, depending on the target analyte and collected sample. Methods of detecting and/or measuring various analytes are well known in the art. For example, methods of measuring albumin are known to those skilled in the art and are also described in US . Patent Publication No. US-2003-0022262-A1 , published January 30, 2003, entitled "METHODS FOR DETECTING EARLY RENAL DISEASE IN ANIMALS," which is incorporated herein in its entirety by reference

The detection or measurement of certain target analytes can be used to diagnosis various diseases. For example, collected urine can be tested for microalbuminuria, which is an indicator of early renal disease. Similarly, albumin and other higher molecular weight proteins, such as immunoglobulin, can be measured to detect renal disease and/or the stage of such disease.

Also contemplated are kits suitable for collecting urine samples using the devices and methods disclosed herein. Thus, the kits contain the sample collection devices of the present invention and, if desired, associated components, such as, but no limited to, sealable plastic bags, vials, tubes, towels, inserts and tests for the target analyte. The devices or kits can also be components of larger systems for analyzing the collected samples.

The following examples are provided for the puipose of illustration and are not intended to limit the scope of the present invention.

EXAMPLES Example 1

This example compares different treatments of cellulose sponges to permit the use of such treated sponges to collect and release urine samples to be tested for the presence of a target analyte without substantially altering the concentration of the target analyte in the samples.

White cellulose sponges (product #2442-6, Minnesota Mining & Manufacturing Company, Maplewood, Minnesota (3M)) were treated in one of several different solutions for one hour at room temperature (treated sponges). Some sponges received no treatment (untreated sponges). Treatment agents (TA) used included phosphate buffered saline (PBS) or deionized water containing (a) bovine serum albumin (BSA) (available from Sigma Chemical Co., St. Louis, MO) (b) soy protein acid hydolysate (available from Sigma), (c) polyoxyethylene sorbitan monolaureate (Tween® 20) (available from Fisher Scientific Corp., Hampton, NH), or (d) bacto yeast extract (available from Difco, BD Diagnostic Systems, Maryland). The treated sponges were squeezed to remove excess solution and then dried overnight at room temperature (RT). To measure the efficacy of each treatment, sponges were then soaked for one hour at 4°C in one of the following solutions: (a) canine urine (control urine) or (b) urine containing 5 milligrams (mg) of canine serum albumin per deciliter (dl) canine urine (CSA urine). Absorbed control urine and CSA urine samples were each squeezed from the respective sponge (released urine). The amount of albumin present in the released urine samples was determined using an enzyme-linked immunosorbent assay (ELISA) for albumin as follows: MaxiSorp™ C8 Break-apart Microwells (available from Nunc) were coated with 1 microgram per milliliter (μg/ml) anti-CSA IgG (purified monoclonal antibody, TNB3 (disclosed in US. Patent Publication No. US-2003-0022262-A1, ibid.), covered, and incubated overnight at 4° C. The coated plates were washed 4 times with PBS/ 0.05% Tween 20 / 0.1 % ProClin 300 (available from Supelco, Bellfonte, PA) using a plate washer. The plates were blocked with 200 microliters (μl) per well StabilCoat™ (available from Surmodics) for at least 60 minutes at RT. Samples were diluted to a urine specific gravity of 1.010 with the appropriate volume of water. Diluted canine serum albumin-horse radish peroxidase (CSA-HRP) competitor was mixed in a 1:1 ratio with samples and standards. One hundred microliters of the mixtures were plated onto the antibody-coated plates and incubated for 30 minutes (min) at RT. The plates were washed 4 times with PBS/ 0.05% Tween 20 / 0.1% ProClin 300 using a plate washer. One hundred microliters of TMB Peroxidase Two Component System (KPL) developer was added to each well and incubated for 30 min at RT. The reaction was stopped with 100 μl 1 M H₃PO . The O.D. was read at 450 nm on a spectrophotometer and the concentration (mg/dl) determined from the standard curve.

The concentration of albumin in samples released from sponges treated with PBS that had been soaked in CSA urine was 2.9 mg/dl albumin. The concentration of albumin in samples released from untreated sponges soaked in CSA urine was 1.8 mg/dl. The concentration of albumin in CSA urine (prior to its exposure to sponges) was 5.7 mg/dl. The concentrations of albumin (reported in mg/dl) released from the sponges treated with other treatment agents and soaked in CSA urine are shown below in Table 1.

Table 1.

Example 2

This example compares the ability of different concentrations of Tween 20 to permit the use of sponges so treated to collect and release urine samples to be tested for the presence of a target analyte without substantially altering the concentration of the target analyte in the samples.

White cellulose sponges (product #2442-6, 3M) were treated with varying concentrations of Tween 20 in PBS and tested for their ability to not substantially alter the concentration of albumin in a sample, using the procedures described in Example 1, except that the treated sponges were soaked in canine urine containing 5 mg/dl, 2.5 mg/dl or 1 mg/dl CSA. The results (reported in mg/dl albumin) are shown in Table 2.

Table 2.

*prior to exposure to sponge Example 3

This example compares the effect of different treatment times on the ability of sponges so treated to collect and release urine samples to be tested for the presence of a target analyte without substantially altering the concentration of the target analyte in the samples.

Yellow and white cellulose sponges (product #2436-8 and # 2442-6, respectively, 3M) were treated in a solution of 0.1% Tween 20 in PBS and tested using the procedures described in Example 1 except that the treatment time was either 10, 30, or 60 minutes (min) in a screen cage, and, after drying overnight in the cage, the treated sponges were soaked in canine urine containing 5 mg/dl, 1 mg/dl or 0 mg/dl CSA. in canine urine. The results (reported in mg/dl albumin) are shown below in Table 3.

Table 3

"prior to exposure to sponge

Example 4

This example compares the effect of different drying conditions on the ability of sponges so treated to collect and release urine samples to be tested for the presence of a target analyte without substantially altering the concentration of the target analyte in the samples.

White cellulose sponges (product #2442-6, 3M) were treated in a solution of 0.1% Tween 20 in deionized water and tested using the procedures described in Example 1, except that the treatment time was 15 minutes, and after treatment, the sponges were removed, then either (a) dried uncaged or (b) compressed in a cage and dried, as follows: (a) at RT (about 22°C) overnight for both uncaged and caged, (b) at 37°C for at least 30 minutes if uncaged or at least 1 hour if caged, or (c) at 55°C for at least 30 minutes for both uncaged and caged. The compression method uses a "cage" in which the sponge is compressed between 2 stainless-steel pieces of mesh screening. The results (reported in mg/dl albumin) are shown in Table 4.

Table 4.

*prior to exposure to sponge

Example 5

Yellow cellulose sponges (product #2436-8, 3M) were treated with varying concentrations of Tween 20 in PBS and tested according to the procedures described in Example 1, except that the treatment time was 15 minutes. The results are shown in Table 5.

Table 5.

*prior to exposure to sponge

Example 6

This example compares the ability of different concentrations of Tween 20 diluted into either PBS or deionized water to permit the use of sponges so treated to collect and release urine samples to be tested for the presence of a target analyte without substantially altering the concentration of the target analyte in the samples.

White cellulose sponges (product #2442-6, 3M) were treated with varying concentrations of Tween 20 in PBS or deionized water and tested according to the procedures described in Example 1, except that the treatment time was 10, 30, or 60 minutes. The results are shown in Table 6. Table 6.

Example 7

This example describes testing of urine collection devices produced on a large scale. The large scale process uses 20 stock sheets of sponge for each ran.

Twenty 8 -inch x 11-inch sheets of white cellulose sponge (product #2442-6, 3M) were treated in 0.1% Tween 20 in deionized water for 15 minutes at RT. Following treatment, the sheets were cut into small wedges. The cut sponges were then compressed to remove excess liquid. The sponges were then dried overnight in their compressed state at room temperature. Twenty-four sponges from the large scale process were then tested for their ability to collect and release urine samples without substantially altering the albumin concentration between the pre-treated and released samples for use in microalbuminuria testing.

Canine urine was adjusted to a specific gravity of 1.010 and canine serum albumin added to a final concentration of 5 mg/dl (CSA urine). Two milliliters (ml) of CSA urine were added to each of the 24 test sponges. The sponges were then placed in individual plastic bags, sealed and stored overnight at 4°C. The sponges were squeezed to release the urine samples and the amount of CSA in each released urine sample was determined as described in Example 1. The results are shown in Table 7.

Table 7.

"prior to exposure to sponge Example 8

This example demonstrates the effect of treating different colored sponges with various concentrations of Tween 20 in either water or PBS.

White, yellow, and orange sponges (all from 3M) were each treated under each of the following conditions: (a) treating in 1% Tween 20 in either deionized water or PBS for 2 hours; (b) treating in 0.2% Tween 20 in either water or PBS for 30 minutes; and (c) treating in either water or PBS, with no Tween 20, for 2 hours. Following treatment, the sponges were compressed in cages and dried at RT overnight. Treated sponges were tested as described in Example 7, except that the sponges were stored for 1 hour instead of overnight. The results (reported in mg/dl albumin) are shown in Table 8.

Table 8.

* prior to exposure to sponge

Example 9

This Example illustrates the absorbability and expandability properties of 3M cellulose sponges treated according to the procedure of Example 7.

Following treatment, the approximately (~) 12 millimeter (mm) thick sponge sheets were cut into trapezoid-shaped pieces measuring ~3 mm x -0.5 mm x -1.5 mm x -3 mm; at that time, the sponges were still -12 mm thick. The cut sponges were then compressed and air-dried overnight in their compressed state as described in Example 7. After compression and drying, the sponges were -2 mm thick.

Three sponges treated, compressed and dried as described in this Example, each were weighed both prior to being exposed to liquid (dry state) and following exposure to liquid (wet state); and a wet/dry weight ratio was calculated. The amount of liquid absorbed as the sponges assumed the wet state was noted. Each of the sponge was then squeezed to release absorbed liquid, and the volume of the released liquid was measured. The results are shown in Table 9.

Table 9.

During the absorption process, the sponge material expanded to a thickness of -16 mm. The sponges absorbed -5.5 ml which equals -9.3 ml/gram of sponge. Upon squeezing, -4.4 ml of liquid was released which is -80% of the absorbed sample.

Example 10

This example illustrates the use of varying BSA concentrations to treat cellulose sponges.

Cellulose sponges were obtained from Spontex (Columbia, Tennessee) and 3M and treated with varying concentrations of BSA and tested using the procedures described in Example 1, except that the treated sponges were soaked in canine urine containing 1.5 mg/dl CSA. The results are shown below in Table 10.

Table 10.

*prior to exposure to sponge

Example 11

This example illustrates the use of various treatment agents to treat cellulose sponges to permit the use of such treated sponges to collect and release urine samples to be tested for the presence of a target analyte without substantially altering the concentration of the target analyte in the samples.

White cellulose sponges (product #2442-6, 3M) were treated with Tween 20, Tween® 80 (available from JT Baker), NP-40 (available from Sigma), sodium dodecyl sulfate (SDS) (available from Fisher), StabilCoat, and ProClin 300, and tested using the procedures described in Example 1, except that the treated sponges were soaked in canine urine containing 1.5 mg/dl CSA. The results are shown in Table 11. Table 11.

"prior to exposure to sponge

While various embodiments of the present invention have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. It is to be expressly understood, however, that such modifications and adaptations are within the scope of the present invention, as set forth in the following claims:

Claims

What is claimed is:

1. A sample collection device for collecting a sample suspected of containing a target analyte, said device comprising treated absorbent material capable of absorbing and releasing at least a portion of said sample without significantly altering the concentration of the target analyte in said sample.

2. A method of producing a sample collection device containing treated absorbent material capable of absorbing and releasing the sample, said method comprising the steps of:

(a) contacting the absorbent material with a buffer, a detergent or a protein;

(b) optionally compressing the absorbent material; and

(c) drying the absorbent material to produce the sample collection device.

3. A device produced according to the method of Claim 2.

4. A method to obtain a sample for analysis, said method comprising:

(a) absorbing said sample onto a sample collection device comprising treated absorbent material capable of absorbing and releasing said sample without significantly altering the concentration of a target analyte in said sample; and

(b) releasing a sufficient amount of said sample from the sample collection device to conduct said analysis.

5. A method to detect or measure a target analyte in a sample, said method comprising:

(a) absorbing said sample onto a sample collection device comprising treated absorbent material capable of absorbing and releasing said sample without significantly altering the concentration of a target analyte in said sample;

(b) releasing a sufficient amount of said sample from the sample collection device; and

(c) detecting or measuring the target analyte in the released sample.

6. A kit comprising a sample collection device having a treated absorbent material capable of absorbing and releasing a sample without substantially altering the concentration of a target analyte in said sample.

7. The kit according to Claim 6, wherein said kit further comprises a ^' container for said sample collection device.

8. The kit according to any of Claims 6-7, wherein said kit further comprises a test for detecting or measuring said target analyte.

9. The device, method or kit according to any one of Claims 1-8, wherein said absorbent material comprises cellulose, polyethylene, polyurethane, polyester, paper or cotton.

10. The device, method or kit according to Claim 9, wherein said absorbent material is cellulose.

11. The device, method or kit according to Claim 10, wherein said absorbent material is a cellulose sponge.

12. The device, method or kit according to any one of Claims 1-12, wherein said absorbent material is exposed to a detergent, a buffer or a protein prior to absorbing said sample.

13. The device, method or kit according to Claim 12, wherein said detergent is Tween-20, Tween-80, octyl glucoside, Triton or NP-40.

14. The device, method or kit according to any one of Claims 1-13, wherein said absorbent material releases at least 10% of the absorbed sample.

15. The device, method or kit according to any one of Claims 1-14, wherein said absorbent material can absorb at least twice its weight in sample.

16. The device, method or kit according to any one of Claims 1-15, wherein said absorbent sample absorbs at least 5 milliliters of sample per gram of absorbent material.

17. The device, method or kit according to any one of Claims 1-16, wherein said absorbent sample expands in at least one dimension to at least 5 times greater after absorbing said sample.

18. The device, method or kit according to any one of Claims 1-17, wherein said sample is a bodily fluid.

19. The device, method or kit according to any one of Claims 1-18, wherein said bodily fluid is urine, blood, serum or saliva.

20. The device, method or kit according to Claim 19, wherein said bodily fluid is urine.

21. The device, method or kit according to any one of Claims 1-20, wherein said target analyte is albumin.

22. The device, method or kit according to any one of Claims 1-21, wherein said sample collection device further comprises a handle.

23. The device, method or kit according to Claim 22, wherein said handle is attached to the absorbent material.

24. A urine collection device comprising a cellulose sponge attached to a handle, wherein said cellulose sponge: (i) is exposed to a non-ionic detergent prior to contact with urine; (ii) expands in at least one dimension at least 5 times greater after contact with said urine by absorbing at least 5 milliliters of urine per gram of said cellulose sponge; and (iii) releases at least 10% of the absorbed urine.