PatentDe  


Dokumentenidentifikation EP1459054 20.12.2007
EP-Veröffentlichungsnummer 0001459054
Titel LESEVORRICHTUNG, VERFAHREN UND SYSTEM FÜR LATERALFLUSS-ASSAYTESTSTREIFEN
Anmelder Kimberly-Clark Worldwide, Inc., Neenah, Wis., US
Erfinder KAYLOR, Rosann Marie, Cumming, GA 30041, US;
YANG, Difei, Alpharetta, GA 30005, US;
KNOTTS, Michael Eugene, Roswell, GA 30075, US
Vertreter derzeit kein Vertreter bestellt
DE-Aktenzeichen 60223402
Vertragsstaaten AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, IE, IT, LI, LU, MC, NL, PT, SE, SK, TR
Sprache des Dokument EN
EP-Anmeldetag 13.11.2002
EP-Aktenzeichen 027984608
WO-Anmeldetag 13.11.2002
PCT-Aktenzeichen PCT/US02/37330
WO-Veröffentlichungsnummer 2003058220
WO-Veröffentlichungsdatum 17.07.2003
EP-Offenlegungsdatum 22.09.2004
EP date of grant 07.11.2007
Veröffentlichungstag im Patentblatt 20.12.2007
IPC-Hauptklasse G01N 21/86(2006.01)A, F, I, 20051017, B, H, EP
IPC-Nebenklasse G01N 33/558(2006.01)A, L, I, 20051017, B, H, EP   

Beschreibung[en]
Background of the Invention

Membrane-based test devices, particularly devices used in diagnostic medicine, employ a variety of internal and external calibrators to provide a qualitative or a quantitative result for an analyte of interest in a test solution. One type of membrane-based test device is a lateral flow assay.

In general, lateral flow assays are membrane-based test devices in which a sample that is suspected of containing the analyte of interest is placed at or near one end of a membrane strip. The sample is carried to the opposite end of the membrane strip by a liquid phase that traverses the membrane strip by capillary action. While traversing the membrane strip, the analyte in the test sample, if any, encounters one or more "capture" reagents with which it may react to produce a detectable signal.

Home use assay devices such as pregnancy tests and the like are now well established. Home use assays may be intended to detect physiological changes in the human body, with the objective of promoting the health and well being of an individual. Consumers are becoming increasingly health conscious, and it is a significant advantage if the consumer is capable of monitoring his or her own bodily functions, including levels of hormones and the like.

There are many different assays that are indicative of physiological changes in the human body. Furthermore, there are many different assay devices that operate by reading an assay strip or test sample. Some devices use fluorescence emission, and others use light reflectance.

United States Patent No. 6,235,241 B1 to Catt et al. ("the Catt patent") is directed to an assay result reader used in conjunction with an assay device. A commercially available device similar to that shown in the Catt patent is known as a UNIPATH CLEAR PLAN Easy® Fertility Monitor. This device is shown in Figure 1 herein, and comprises a fertility monitoring device 21 with a removable hand held cover 22, which fits into a receiver 23 upon the housing 25. Bodily fluids are applied to the test strip 24, and the test strip 24 may be placed into the receiver 23, where the test strip 24 receives light that shines through a window 26 upon the test strip 24. Then, the level of reflected light is analyzed to give a result.

One of the problems with fertility monitoring devices as described is that they are not capable of providing a high degree of sensitivity, in many Instances. That is, some analytes need to be monitored for medical purposes, but do not require a high degree of sensitivity or a sophisticated instrument to detect accurately and precisely the levels of analyte. Many currently available home use reading devices have a low signal to noise ratio, which may be caused in part by the undesirable introduction of excess amounts of stray or ambient light into the viewing window. In conducting precise measurements using a reflectance-based regime, it is critical that the amount of stray ambient light be reduced or eliminated to achieve a high degree of sensitivity. It is therefore highly desirable to maximize the signal to noise ratio, and increase the sensitivity of such reading devices.

Another reading device for home use is known as an ACCUCHECK® Blood Glucose Meter manufactured and distributed by Boehringer Mannheim Diagnostics of Indianapolis, Indiana 46250. The ACCUCHECK® device is a reflectance-based instrument designed for home use in checking blood glucose levels. The instrument does not employ a lateral flow assay. Instead, a user is instructed to place a drop of blood upon a test pad. The reflectance sensor portion of the instrument contains a removable holder, with two rectangular windows.

EP-A-0 308 770 discloses a reagent strip handling mechanism which includes the features in the preamble to claims 1 and 13.

What is needed in the industry is a sensitive reading device designed for lateral flow assay test strips. A reading device that provides an efficient and reliable means for quickly placing a test strip into position to receive a reading or result, while avoiding excess ambient and stray light would be desirable. A reading device providing high sensitivity for detecting hormones and the like would be desirable. A reading device having a window that achieves a high degree of efficiency in the transmission and reflectance of light would be useful.

Summary of the Invention

According to the present invention there is provided a lateral flow assay reading device as claimed in claim 1 and a method as claimed in claim 13. The reading device is configured for detecting an assay result from a membrane strip, in which the result is revealed by the binding of a detectable analyte within a detection zone along the membrane strip. The assay reading device comprises a housing and a receiving port within the housing. The receiving port includes a light barrier structure, and admits a membrane strip directly from the outside of the housing. That is, a membrane strip is inserted into the receiving port. The receiving port is configured for minimizing the introduction of stray or ambient light into the reading device.

A reading mechanism is also provided which includes a source of electromagnetic radiation, and one or more sensors capable of detecting the Intensity of reflected electromagnetic radiation. The source of radiation and the sensors are positioned within the reading mechanism so that when the membrane strip is admitted into the receiving port, the radiation impacts the detection zone upon the membrane strip prior to impacting the sensor.

In another embodiment of the invention, a test kit. Including a lateral flow assay reading device as claimed in claim 1 and a porous liquid permeable membrane strip is provided.

In yet another embodiment of the invention, a system for conducting a lateral flow assays is be provided for detecting the quantity of analyte that resides in a test liquid. The system includes a probe configured for generating a detectable signal, and a membrane strip designed for mobilizing a test liquid. The membrane strip includes a detection zone. Furthermore, a reading device as previously described is employed, with a receiving port and light barrier structure configured for minimizing stray light Into the reader. An assay result having increased sensitivity is achieved by way of the invention.

Brief Description of the Drawings

A full and enabling disclosure of this invention, including the best mode shown to one of ordinary skill in the art, is set forth in this specification. The following Figures illustrate the invention:

  • Figure 1 is a perspective view of the CLEAR PLAN EASY® Fertility Monitor previously discussed;
  • Figure 2 is a perspective view of one embodiment of the reading device of the invention, showing the light barrier structure and receiving port;
  • Figure 3 shows a perspective view of the reading device in which the receiving port 45 has been exploded upwards to reveal details;
  • Figure 3a Is a view of the underside of the top plate, showing interaction of the pressure plate with the top plate in the receiving port;
  • Figure 4 shows a cross sectional view of the receiving port in one embodiment of the invention, as taken along line 4-4 of Figure 2;
  • Figure 5 shows an alternate embodiment of the reading device of the invention having a channel on the upper surface of the reading device configured to receive a membrane test strip;
  • Figure 5a shows a cross sectional view of the membrane strip receiving portion of the reading device as taken along lines 5a-5a in Figure 5;
  • Figure 5b shows a design layout for the electronics of the reading device, including a microcontroller, LCD display, and the like;
  • Figure 6 shows a closer view of the membrane strip receiving portion of the embodiment previously shown in Figure 5, showing one particular application in which the membrane strip includes a nub that interlocks into one or more notches; and
  • Figure 7 shows a cross sectional view of the structure shown in Figure 6, as taken along lines 7-7 in Figure 6.

Detailed Description of the Invention

Reference now will be made to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, not as a limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in this invention without departing from the scope of the invention. For instance, features illustrated or described as part of one embodiment can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

In the invention, an optical reflectance meter or reading device is provided. The reading device may be used with lateral flow assays to provide quantitative results. The metering device may be designed to provide improved sensitivity and increased accuracy. The method and system of the invention may serve as a more accurate and sensitive alternative to direct visual examination of a membrane assay strip.

The reading device of the invention may include various components including a light source such as a light emitting diode ("LED") or laser, a light beam modulator, mirror, lenses, photo diodes, sample holders and other optional components, as further described herein. In any event, the sample holder provides for easy insertion of membrane test strips, with a minimal amount of pass through of ambient or stray light, thus reducing the noise level. A reading device having an improved signal to noise ratio Is provided, with greater sensitivity. The sample holder may include a mechanical design having a spring-loaded member. In some applications, at least two different stop positions are provided for the same membrane test strip wherein the first stop position may be used to provide a reference reading, and a second stop position may be used to read actual samples in a detection area or a detection zone.

One embodiment of the invention is further illustrated in Figure 2, wherein a reading device 40 receives a membrane strip 41 into a receiving port 45 to provide a result. A light barrier structure 28 also is shown. A detection zone 42 upon the membrane strip 41 is located some distance from a reference zone 43, which gives a base line reference or calibration reading. In the particular embodiment shown, the detection zone 42 is provided towards-the outside, while the reference zone 43 is towards the inside, but it should be recognized that the positions of these respective zones could be reversed from that which is shown in Figure 2.

The reading device 40 may include a housing exterior 44, and on/off switch 49, and housing interior (not shown in Figure 2). In Figure 2, an LCD display 60 is shown.

In Figure 3, the light barrier structure 28 is shown in a view with the components exploded upwards from the housing exterior 44 of the reading device 40. The top plate 50 is also shown. The device shown in Figure 3 corresponds to the device shown In Figure 2, and is essentially the same embodiment. The receiving port 45 is bounded on its lower edge by bottom plate 56, and on its upper edge by top plate 50. Within the receiving port 45 there is a pressure plate 51, under which the membrane strip 41 is inserted. The pressure plate 51 is held by spring 52 in a resilient engagement with the membrane strip 41 (not shown in Figure 3). The membrane strip 41 is held over aperture 54, which happens to be circular in Figure 3. However, the aperture could be of many different shapes and sizes, and most preferably approximates the size and/or shape of the zone of interest upon the membrane strip 41 that is to be examined. The channel 53 forms the conduit through which the membrane strip 41 is inserted. Screws 55a-d holds the top plate 50 down upon the housing 44.

In Figure 3a, the underside of top plate 50 is shown, revealing a recess 58. Within the recess 58 resides the pressure plate 51, which is held in springing engagement by spring 52. Also shown is a light-absorbing member 57, which rests upon the top or upper surface of membrane strip 41 (see Figure 2). The light-absorbing member 57 acts as a low reflectance specimen in contact with the aperture 54 that allows the instrument to be calibrated to eliminate the effects of internal reflections within the sensor housing. In practice, such calibration can be performed automatically by the microprocessor when power is first applied to the instrument. Furthermore, the light absorbing member 57 absorbs any light which is transmitted completely through the membrane strip 41, so that such light is not reflected back downward towards the sensor 92 (see Figure 5a). In this way, the sensitivity and signal to noise ratio of the reading device 40 is maximized.

The light-absorbing member 57 may include almost any type of material that is capable of absorbing light, such as a black or dark colored flocking, plastic, metal, felt, or other material. For example, materials that are used in the photography arts that are known to absorb light could be employed. Such materials may be flexible and/or conformable, and may be comprised of felt. There is no particular size or shape that is preferred for a light-absorbing member 57, but it is important that the light-absorbing member 57 cover completely the area under which the membrane strip 41 is being impacted by light from its underside. One optional feature of the light-absorbing member 57 would be to provide a flexible or conformable form fit to the test strip, by using felt or drapable material.

Figure 4 shows a cross section of the light barrier structure 28 with receiving port 45 as shown in lines 4-4 of Figure 2. The receiving port 45 comprises a pressure plate 51 that fits between a top plate 50 and a bottom plate 56. A membrane strip 41 is inserted below the pressure plate 51, where the detection zone 42 of the membrane strip 41 may be placed directly over a light pathway 59. Light generated by a light source (now shown in Figure 4) such as a light emitting diode (LED) passes upwards along arrow 59a and is reflected downward from membrane strip 41 along arrow 59b as seen in Figure 4.

The internal light emitting and sensing components of the reading device shown in Figures 2-4 is essentially the same as that shown in Figures 5-5a.

It is important to the sensitivity of the reading device 40 that the light aperture located immediately below the membrane strip 41 is of a size that approximates the size of detection zone 42 upon the membrane strip 41. In other applications, the aperture (not shown in Figure 4) may be slightly larger than the detection zone 42. In some cases, the aperture could be about 1.3 or even 1.8 times larger in area than the detection zone 42. However, it has been found that the closer the aperture corresponds to the size of the detection zone 42 upon the membrane strip 41, the higher the signal to noise ratio that can be achieved by the reading device 40, and the more sensitive will be the reading device 40. Furthermore, the membrane strip 41 also may include a reference zone 43 at another location upon the membrane strip 41. The reference zone 43 may be placed over the light pathway 59 in order to obtain a reference reading or a calibration of the reading device 40. Then, in a second step, the detection zone 42 may be placed over the light pathway 59 to obtain the sample reading. A spring 52 is shown in cross section above the light-absorbing member 57, which fits just above the membrane strip 41. The light-absorbing member 57 is capable of absorbing light that may undesirably enter the receiving port 45 from outside. Furthermore, the light-absorbing member 57 is capable of absorbing light that may proceed through the light pathway 59, and be transmitted completely through the membrane strip 41. This prevents reflection downward of stray light, improving sensitivity.

One alternate embodiment of the invention is shown In Figure 5, A light barrier structure 81 is provided, below an LCD display 74. The light barrier structure is bounded from above by top plate 72, and from below by bottom plate 78. A reading device 65 is comprised of a housing 73 having a receiving port 64 bounded upon the top by a hood 66. The receiving port 64 consists in part of a channel 68 that runs vertically as shown in Figure 5. An aperture 69, (which in Figure 5 happens to be in the shape of a rectangle) is located In the bottom of the channel 68. A first notch 70 and a second notch 71 are provided as locating points to receive a membrane strip having nub 77 which will be seen in Figure 5a. Screws 67a and 67b hold the hood 66 down upon the top plate 72. The function of the hood 66 is to reduce the amount of ambient light that impacts near the aperture 69, increasing the sensitivity of the reading device 65, and improving the signal to noise ratio of results obtained. An on/off switch 75 is shown near the right side of the housing 73.

Figure 5a is a basic schematic taken in cross section along lines 5a-5a of Figure 5 showing the basic internal architecture of the reading device 65 employed in the invention. Screws 67a-b hold down a top plate 72 upon bottom plate 78, and also function to hold hood 66 to plate 72. In cross section, one can see a light-absorbing member 80 that is positioned above membrane strip 76. A nub 77 fits into first notch 70 to register the membrane strip 76 in the appropriate position to receive light 91 from a light emitting diode (LED) 90. The light 91 travels to the membrane strip 76, and then is reflected downward along light pathway 93 to a sensor 92. In some applications, the sensor 92 is a diode. A housing 73 is also seen, and may include other components that are not shown in Figure 5a.

A basic schematic diagram of a reading device 65 is shown in Figure 5b. In Figure 5b, an LCD display 74 having 16 characters is shown on the right side of Figure 5b. The LCD display 74 is connected to a micro controller 95. The microcontroller 95 directs the activities of the reading device 65, and regulates the light energy output of the light emitting diode (LED) 90, as shown in the lower left portion of Figure 5b.

Likewise, a photo diode 92 receives light energy, and converts such energy to signals that are transmitted to a preamplifier 79, and then to the microcontroller 95. Eventually, the data output or result of an assay is illuminated on the LCD display 74, shown in Figure 5.

The wavelength of the illumination radiation should be chosen to fall within the wavelength range over which the detector (photodiode) has appreciable responsivity (typically 400 nm to 1000 nm for a silicon photodiode. Furthermore, the wavelength of the illuminating radiation should be chosen to be near the maximal absorption wavelength of the detectable material used as the label in the lateral flow assay.

It is generally accepted that the detectable material used as a label or probe in the assay is one that will interact with light in the visible or near visible range, by absorption. For example, if the probe is a substance that appears blue to the naked eye when concentrated, the ideal electromagnetic radiation would likely be yellow. Particulate direct labels, including metallic and gold sols, non-metallic elemental sols (i.e. selenium or carbon) and colored latex (polystyrene) particles are suitable examples, as further described herein.

The source of light represented by the light emitting diode 90 may be comprised entirely of commercially available components. Suitable examples are commercially available LED's, preferably chosen to provide a suitable wavelength of light that is strongly absorbed by the detectable material concentrated in the detection zone 42. If desired, an array of LED's, which are energized in turn, could be used.

Figure 6 shows a more detailed view of the top plate 72 of one embodiment of the invention, which is seen in Figure 5. A membrane strip 76 having a nub 77 is registered into first notch 70 as shown. In some embodiments of the invention, the nub 77 registers with the first notch 70 to take a reading from a reference zone 83 on the membrane strip 76. Then, once a reference or calibration reading is obtained, the membrane strip 76 may be lifted up and the position changed so that the nub 77 is integrated into the second notch 71. A detection zone 82 is shown on membrane strip 76. The detection zone 82 would then be placed over the aperture (aperture is not shown in Figure 6) to obtain the test sample reading. The channel 68 into which the membrane strip 76 is placed is shown in Figure 6.

Figure 7 shows a cross sectional view along lines 7-7 of Figure 6. Screws 67a-b holds the hood 66, and a top plate 72 to a bottom plate 78. A membrane strip 76 is provided in the channel 68, so that the nub 77 is fitted into first notch 70. The light-absorbing member 80 is positioned over the membrane strip 76 in Figure 7. The light-absorbing member 80 may include those materials described for component 57, including almost any type of material that is capable of absorbing light, such as a black or dark colored flocking, felt, plastic, metal, or other material.

The membrane-based device of the invention comprises several components, including a membrane, a sample pad, a conjugate pad and a wicking pad, or a combination of these items. The membrane typically includes at least two zones, that is, one or more detection zone(s) and one or more control or reference zone(s). A sample pad contacts one end of the conjugate pad.

One design of the assay device includes a liquid sample flow direction having a sample pad, conjugate pad, detection zone, and a pad, typically provided in that order from one end to the other end. In general, the wicking pad assists in promoting capillary action and fluid flow one-way through the membrane strip. The pad "pulls" the liquid containing the analyte along the membrane from one end of the membrane to another end of the membrane.

Probes used in the invention may comprise beads or particles. Such beads or particles may be comprised of latex, or other suitable material, as further described herein. In some applications, plain particles are used, while other applications may employ particles with capture reagents and/or antibodies conjugated upon the outer surface of the particle. The particles are typically colored with a dye that is visible to the eye, or to a detection apparatus. In other embodiments, the particles may include light absorbing materials such as metal sols, gold, or silver particles. Gold nanoparticles have been found to be suitable in some applications.

In one application of the invention a system for conducting a lateral flow assay is provided to detect the quantity of analyte that resides in a test liquid. The system comprises employing a probe analyte conjugate complex that is capable of generating a detectable signal. Furthermore, a membrane strip is provided and configured for mobilizing a test liquid which contains both a probe and an analyte conjugate. The membrane strip comprises a detection zone, in which the detection zone has deposited thereon a first capture reagent. The first capture reagent is immobilized upon the detection zone, and is configured for attaching to probe analyte conjugates to immobilize the probe analyte conjugates, thereby forming a sandwich complex within the detection zone.

A detection line may contain an immobilized second capture reagent (i.e.: antibody or other conjugating species), which serves to immobilize the unbound probes by binding to form a control probe complex (i.e.: immobile species) on a capture line. When significant numbers of the probe are immobilized in this way, a visibly distinctive line appears at one or more detection lines on the membrane strip. The control line may be embedded with a predetermined amount of second capture reagent.

In some instances, a comparison is made between the intensity levels of the calibration or control lines (or zone), or some other reference standard, and the detection line of the membrane strip, to calculate the amount of analyte present in a sample. This comparison step is accomplished with the reading device further described herein.

The membrane strip employed in the assay may be a cellulose ester, with nitrocellulose usually providing good results, but the invention is not limited to such compositions for the membrane strip.

It is to be understood that the invention can be configured for detecting a broad range of analytes, including therapeutic drugs, drugs of abuse, hormones, vitamins, glucose proteins (including antibodies of all classes), peptides, steroids, bacteria or bacterial infection, fungi, viruses, parasites, components or products of bacteria, allergens of all types, antigens of all types, products or components of normal or malignant cells, and the like.

The following analytes are examples of analytes that may be tested using the present invention: T.sub.4, T.sub.3, digoxin, hCG, insulin, theophylline, luteinizing hormone, organisms causing or associated with various disease states, such as streptococcus pyogenes (group A), Herpes Simplex I and II, cytomegalovirus, chlamydiae, and others known in the art.

United States Patent No. 4,366,241 (Tom et al.) lists at columns 19-26 a variety of potential analytes of interest that are members of an immunologic pair, including proteins, blood clotting factors, hormones, microorganisms, pharmaceutical agents, and vitamins. Any of these analytes are suitable for use as the analyte in present invention.

Other examples of preferred ligands or analytes that may be detected include the following: human bone alkaline phosphatase antigen (HBAPAg); human chorionic gonadotropin (hCG); human luteinizing hormone (hLH); human follicle stimulating hormone (hFSH); creatine phosphokinase MB isoenzyme; ferritin; carcinoembryonic antigen (CEA); prostate specific antigen (PSA); CA-549 (a breast cancer antigen); hepatitis B surface antigen (HBsAg); hepatitis B surface antibody (HBsAb); hepatitis B core antigen (HBcAg); hepatitis B core antibody (HBcAb); hepatitis A virus antibody; an antigen of human immunodeficiency virus HIV I, such as gp 120, p66, p41, p31, p24 or p17; the p41 antigen of HIV II; and the respective antiligand (preferably a monoclonal antibody) to any one of the above ligands. The HIV antigens are described more fully in United States Pat. No. 5,120,662 and in Gelderblom et al., Virology 156: 171-176 1987 .

As used herein, the term "probe" refers generally to a structure that is capable of carrying an analyte in a lateral flow assay to a detection area or zone, which may or may not be in the form of a particle or microparticle. Furthermore, as used herein the term "probe-conjugate" refers to a species that is capable of carrying an analyte in a lateral flow assay to form a probe-conjugate complex, which binds a first capture reagent in a detection zone of a membrane strip to become a "sandwich complex" in the detection zone.

As used herein, the term "microparticle" is a more specific reference to a particular type of probe, and may include any beads or probes to which an antibody may be bound, whether covalently, or non-covalently such as by adsorption. An additional requirement for some particles that are used in a quantitative assay is that the particle contributes a signal, usually light absorption, which would cause the zone in which the particles were located to have a different signal than the rest of the membrane,

Optionally, metallic particles or metal could be used as the probe in the invention. These particles are commercially available as microspheres of substantially uniform diameter from companies such as British Biocell International, of Cardiff, United Kingdom.

By the phrase "membrane" or "membrane strip" as used herein is meant a test device or strip that employs a membrane and one or more reagents to detect the concentration of an analyte of interest in a test solution, preferably an aqueous test solution. At least one of the reagents associated with the membrane device is a binding partner of the analyte of interest.

Latex microparticles for use In the present invention are commercially available as polymeric microspheres of substantially, uniform diameter (hereinafter "polymeric microspheres"), such as from Bangs Laboratories of Carmel, Indiana, or Dow Chemical Co. of Midland, Michigan. Although any polymeric microsphere that is capable of adsorbing or of being covalently bound to a binding partner may be used in the present invention, the polymeric microspheres typically are composed of one or more members of the group consisting of polystyrene, butadiene styrenes, styreneacrylic-vinyl terpolymer, polymethylmethacrylate, polyethylmethacrylate, styrene-maleic anhydride copolymer, polyvinyl acetate, polyvinylpyridine, polydivinylbenzene, polybutyleneterephthalate, acrylonitrile, vinylchloride-acrylates and the like or an aldehyde, carboxyl, amino, hydroxyl, or hydrazide derivative thereof.

The underivatized polymeric microspheres, such as polystyrene, are hydrophobic and passively adsorb other hydrophobic molecules, including most proteins and antibodies. Techniques for adsorbing a protein or polypeptide on a hydrophobic particle are provided in the publication by Cantarero, et al. "The Absorption Characteristics of Proteins for Polystyrene and Their Significance in Solid Phase Immunoassays," Analytical Biochemistry 105, 375-382 (1980) ; and Bangs, "Latex Immunoassays," J. Clin. Immunoassay, 13 127-131 (1980) .

Various procedures for adsorbing molecules on polymeric microspheres are also described, in general terms, in Bangs, L. B., "Uniform Latex Particles," presented at a workshop at the 41st National Meeting, Amer. Assoc. Clin. Chem., 1989 , and available in printed form from Seragen Diagnostics Inc., Indianapolis, Ind.; or Galloway, R. J., "Development of Microparticle Tests and Immunoassays, " i.e., Seradyn Inc. of Indiana

The test solution may be a component of a biological fluid, such as extracted, diluted, or concentrated from a plant or animal, preferably a mammal, more preferably a human. Especially preferred biological fluids are serum, plasma, urine, ascites fluid, peritoneal fluid, amniotic fluid, synovial fluid, cerebrospinal fluid and the like, or a concentrate or dilution thereof.

In the practice of the invention, calibration and sample testing may be conducted under essentially exactly the same conditions at the same time, thus providing highly reliable quantitative results, and increased sensitivity.

The invention also may be employed for semi-quantitative detection. As the multiple control lines provide a range of signal intensities, the signal intensity of the detection line can be compared (i.e. such as for example, visually) with the control lines. Based on the intensity range the detection line falls, the possible concentration range for the analyte may be determined. The probes may be latex beads labeled with any signal generating species or the labeled latex beads further conjugated with antibodies.

It is understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary constructions. The scope of the invention is defined by the appended claims.


Anspruch[de]
Lateral-Flow-Assay-Lesevorrichtung, wobei die Lesevorrichtung so aufgebaut ist, um ein Assay-Ergebnis von einem Lateral-Flow-Assay-Membranstreifen (41; 76) zu erfassen, wobei das Assay-Ergebnis durch Einbinden eines erfassbaren Analyts innerhalb einer Erfassungszone (42; 82) entlang des Membranstreifens (41; 76) entnommen wird, die aufweist: (a) ein Gehäuse (44; 73), das eine Außenseite und einen Innenraum besitzt; (b) eine Aufnahmeöffnung (45; 64) innerhalb des Gehäuses, um einen Membranstreifen direkt von der Außenseite des Gehäuses zu dem Innenraum des Gehäuses der Leseeinrichtung aufzunehmen, wobei die Aufnahmeöffnung eine Lichtbarrierestruktur (28; 81) bildet; (c) einen Lesemechanismus, der aufweist: (i) eine Quelle einer elektromagnetischen Strahlung; (ii) einen oder mehrere Sensor(en) (92), die dazu geeignet sind, die Intensität der elektromagnetischen Strahlung zu erfassen, wobei die Quelle der elektromagnetischen Strahlung und die Sensoren (92) innerhalb des Lesemechanismus so positioniert sind, dass dann, wenn der Membranstreifen (41; 76) in die Aufnahmeöffnung (45; 64) aufgenommen wird und durch die Lichtbarrierestruktur (28; 81) umschlossen ist, die elektromagnetische Strahlung auf die Erfassungszone (42; 82) an dem Membranstreifen vor einem Auftreffen auf den Sensor auftrifft, wobei die elektromagnetische Strahlung durch eine Öffnung (54; 69) fortschreitet, bevor sie in die Aufnahmeöffnung eintritt; dadurch gekennzeichnet, dass ein Licht absorbierendes Element (57; 80) innerhalb der Aufnahmeöffnung (45; 64) vorgesehen ist, um Streulicht zu absorbieren, wobei das Licht absorbierende Element (57; 80) eine Absorptionsfläche aufweist, die benachbart dem Membranstreifen (41; 76) in der Aufnahmeöffnung angeordnet ist und unter Benutzung auf der oberen Fläche des Membranstreifens ruht, wobei die Absorptionsfläche vollständig den Bereich abdeckt, unter dem der Membranstreifen (41; 76) durch Licht von seiner Unterseite aus getroffen wird. Lesevorrichtung nach Anspruch 1, wobei die Aufnahmeöffnung (45) eine Druckplatte (51) aufweist, die sich gegen den Membranstreifen (41) anlegt. Lesevorrichtung nach Anspruch 2, wobei die Druckplatte (51) federvorgespannt ist. Lesevorrichtung nach Anspruch 1, wobei die Öffnung (69) länglich ist. Lesevorrichtung nach Anspruch 1, wobei die Öffnung (54) kreisförmig ist. Lesevorrichtung nach Anspruch 1, wobei die Öffnung (54; 69) in einem Bereich dimensioniert ist, der nicht mehr als ungefähr 1,8-mal des Bereichs der Erfassungszone auf dem Membranstreifen entspricht. Lesevorrichtung nach Anspruch 1, wobei die Öffnung (54; 69) in einem Bereich dimensioniert ist, der nicht mehr als ungefähr 1,3-mal des Bereichs der jeweiligen Zone auf dem Membranstreifen entspricht. Lesevorrichtung nach einem vorhergehenden Anspruch, wobei die Aufnahmeöffnung (45; 64) eine erste Anschlagposition für eine Referenzlesung und eine zweite Anschlagposition für eine Probenlesung besitzt. Test-Kit, der die Lateral-Flow-Assay-Lesevorrichtung nach irgendeinem vorhergehenden Anspruch aufweist, zusammen mit einer Assay-Vorrichtung, die einen porösen, flüssigkeitsdurchlässigen Membranstreifen aufweist, wobei die Dicke des porösen, flüssigkeitsdurchlässigen Membranstreifens für elektromagnetische Strahlung durchlässig ist, wobei das Assay-Ergebnis durch spezifisches Einbinden eines erfassbaren Analyts direkt oder indirekt in einem Bindemittel, das in der Erfassungszone immobilisiert ist, erhalten wird. Test-Kit nach Anspruch 9, wobei der Lesemechanismus das Assay-Ergebnis teilweise durch eine Messung mit den Sensoren der elektromagnetischen Strahlung bestimmt, die von a) der Erfassungszone des Membranstreifens und b) einer Kalibrierungszone auf dem Membranstreifen reflektiert ist, wobei ein Vergleich zwischen den Werten, die in (a) und in (b) gemessen sind, vorgenommen wird. System zum Durchführen eines Lateral-Flow-Assays um die Menge eines Analyts, der in einer Testflüssigkeit vorhanden ist, zu erfassen, wobei das System aufweist: (a) ein Prüf-Analyt-Konjugat, das dazu geeignet ist, ein erfassbares Signal zu erzeugen; (b) einen Membranstreifen, wobei der Membranstreifen eine Erfassungszone aufweist, wobei die Erfassungszone darauf niedergeschlagen ein erstes Erfassungsreagenz besitzt, wobei das erste Erfassungsreagenz zum Befestigen an Prüf-Analyt-Konjugaten ausgelegt ist, um die Prüf-Analyt-Konjugate so zu immobilisieren, um einen Sandwich-Komplex innerhalb der Erfassungszone zu bilden; und (c) eine Lesevorrichtung, wie sie in einem der Ansprüche 1-8 beansprucht ist. Lesevorrichtung, Test-Kit oder -System nach einem vorhergehenden Anspruch, wobei das Licht absorbierende Element (57; 80) ein Filzmaterial aufweist, das flexibel und anpassbar ist. Verfahren zum Durchführen eines Lateral-Flow-Assays, um die Menge eines Analyts, der in einer Testflüssigkeit vorhanden ist, zu erfassen, wobei das Verfahren aufweist: (a) Vorsehen von Prüf-Konjugaten auf einem Membranstreifen (41; 76), wobei die Prüf-Konjugate zum Erzeugen eines erfassbaren Signals ausgelegt sind; (b) Vorsehen eines Analyts auf dem Membranstreifen (41; 76); (c) Anbringen des Prüf-Konjugats an dem Analyt, um einen Prüf-Analyt-Konjugat-Komplex zu bilden; (d) wobei der Membranstreifen (41; 76) so aufgebaut ist, um eine Testflüssigkeit, die Prüfmittel enthält, und um Prüf-Analyt-Konjugat-Komplexe zu mobilisieren, wobei der Membranstreifen (41; 76) eine Erfassungszone (42; 82) aufweist; (e) Vorsehen eines ersten Erfassungsreagenz in der Erfassungszone (42; 82), wobei das erste Erfassungsreagenz immobilisiert ist und zum Befestigen an den Prüf-Analyt-Konjugat-Komplexen ausgelegt ist, um die Prüf-Analyt-Konjugat-Komplexe dadurch zu immobilisieren, dass ein Sandwich-Komplex innerhalb der Erfassungszone (42; 82) gebildet wird; (f) Bereitstellen einer Lesevorrichtung, wobei die Lesevorrichtung so aufgebaut ist, um ein Assay-Ergebnis von dem Membranstreifen (41; 76) zu erfassen, wobei die Lesevorrichtung ein Gehäuse (44; 73) umfasst, das eine Außenseite und einen Innenraum und eine Aufnahmeöffnung (45; 64) mit einer Lichtbarrierestruktur (28; 81) besitzt, wobei die Aufnahmeöffnung (45; 64) innerhalb des Gehäuses für einen Zugang zu der Membran direkt von der Außenseite des Gehäuses der Leseeinrichtung zu dem Innenraum des Gehäuses der Leseeinrichtung befestigt wird;

wobei die Lesevorrichtung weiterhin einen Lesemechanismus mit einer Quelle elektromagnetischer Strahlung und einem oder mehreren Sensoren (92), die zum Erfassen der Intensität der elektromagnetischen Strahlung geeignet sind, aufweist;
(g) Blockieren von Umgebungslicht dagegen, dass es die Membranerfassungszone (42; 82) erreicht, um dadurch die Empfindlichkeit zu erhöhen; (h) wobei die Quelle der elektromagnetischen Strahlung und die Sensoren so positioniert sind, dass dann, wenn der Membranstreifen (41; 76) in die Aufnahmeöffnung (45; 64) zugeführt wird, elektromagnetische Strahlung auf die Erfassungszone (42; 82) an dem Membranstreifen (41; 76) auftrifft und dann zu dem Sensor läuft; (i) Einrichten der elektromagnetischen Strahlung so, um durch eine Öffnung (54; 69) zu führen, bevor sie in die Aufnahmeöffnung (45; 64) eintritt;

gekennzeichnet durch
(j) Vorsehen eines Licht absorbierenden Elements (57; 80) innerhalb der Aufnahmeöffnung (45; 64), um Streulicht zu absorbieren, wobei das Licht absorbierende Element (57; 80) eine Absorptionsfläche aufweist, die angrenzend an den Membranstreifen (41; 76) in der Aufnahmeöffnung angeordnet ist und auf der oberen Fläche des Membranstreifens in Benutzung ruht, wobei die Absorptionsfläche vollständig den Bereich abdeckt, unter dem der Membranstreifen (41; 76) durch Licht von dessen Unterseite getroffen wird.
Anspruch[en]
A lateral flow assay reading device, the reading device being configured to detect an assay result from a lateral flow assay membrane strip (41;76), the assay result being revealed by the binding of a detectable analyte within a detection zone (42;82) along the membrane strip (41;76), comprising: (a) a housing (44;73) having an exterior and an interior; (b) a receiving port (45;64) within the housing for admitting a membrane strip directly from the exterior of the housing to the interior of the reader housing, the receiving port providing a light barrier structure (28;81); (c) a reading mechanism comprising: (i) a source of electromagnetic radiation; (ii) one or more sensors (92) capable of detecting the intensity of the electromagnetic radiation, wherein the source of electromagnetic radiation and the sensors (92) are positioned within the reading mechanism such that when the membrane strip (41;76) is admitted into the receiving port (45;64), and enclosed by the light barrier structure (28;81), the electromagnetic radiation impacts the detection zone (42;82) upon the membrane strip prior to impacting the sensor, wherein the electromagnetic radiation proceeds through an aperture (54;69) prior to entering the receiving port; Characterised in that: a light absorbing member (57;80) is provided within the receiving port (45;64) to absorb stray light, the light absorbing member (57;80) comprising an absorption pad located adjacent the membrane strip (41;76) in the receiving port and resting on the upper surface of the membrane strip in use, the absorption pad covering completely the area under which the membrane strip (41;76) is impacted by light from its underside. The reading device of claim 1 in which the receiving port (45) comprises a pressure plate (51) that bears against the membrane strip (41). The reading device of claim 2 in which the pressure plate (51) is spring loaded. The reading device of claim 1 in which the aperture (69) is elongated. The reading device of claim 1 in which the aperture (54) is circular. The reading device of claim 1 in which the aperture (54;69) is sized to an area which is no more than about 1.8 times the area of the detection zone upon the membrane strip. The reading device of claim 1 in which the aperture (54,69) is sized to an area that is no more than about 1.3 times the area of a respective zone upon the membrane strip. The reading device of any preceding claim in which the receiving port (45;64) includes a first stop position for a reference reading and a second stop position for a sample reading. A test kit comprising the lateral flow assay reading device of any preceding claim, together with an assay device comprising a porous liquid permeable membrane strip, wherein the thickness of the porous liquid permeable membrane strip is transmissible by electromagnetic radiation, in which the assay result is revealed by specific binding of a detectable analyte directly or indirectly to a binding agent immobilized in said detection zone. The test kit of claim 9, in which the reading mechanism determines the assay result in part by measuring with the sensors the electromagnetic radiation reflected from: a) the detection zone of the membrane strip, and b) a calibration zone on the membrane strip, wherein a comparison is made between the values measured in (a) and in (b). A system for conducting a lateral flow assay to detect the quantity of analyte residing in a test liquid, the system comprising: (a) a probe-analyte conjugate capable of generating a detectable signal; (b) a membrane strip, the membrane strip comprising a detection zone, the detection zone having deposited thereon a first capture reagent, wherein the first capture reagent is configured for attaching to probe-analyte conjugates to immobilize said probe-analyte conjugates to form a sandwich complex within the detection zone; and (c) a reading device as claimed in any of claims 1-8. The reading device, test kit or system of any preceding claim in which the light-absorbing member (57;80) comprises a felt material that is flexible and conformable. A method of conducting a lateral flow assay to detect the quantity of analyte residing in a test liquid, the method comprising: (a) providing probe-conjugates upon a membrane strip (41;76), the probe-conjugates being configured for generating a detectable signal; (b) providing an analyte on the membrane strip (41;76); (c) attaching the probe-conjugate to the analyte to form a probe-analyte conjugate complex; (d) wherein the membrane strip (41;76) is configured for mobilizing a test liquid containing probes and probe-analyte conjugate complexes, the membrane strip (41;76) comprising a detection zone (42;82); (e) providing In the detection zone (42;82) a first capture reagent, wherein the first capture reagent is immobilized and Is configured for attaching to the probe-analyte conjugate complexes to immobilize said probe-analyte conjugate complexes by forming a sandwich complex within the detection zone (42;82); (f) providing a reading device, the reading device being configured to detect an assay result from the membrane strip (41;76), the reading device including a housing (44;73) having an exterior and an interior and a receiving port (45;64) with a light barrier structure (28;81), the receiving port (45;64) being fitted within the housing for admitting the membrane directly from the exterior of the reader housing to the interior of the reader housing; the reading device further comprising a reading mechanism with a source of electromagnetic radiation and one or more sensors (92) capable of detecting the intensity of the electromagnetic radiation (g) blocking ambient light from reaching the membrane detection zone (42;82), thereby increasing sensitivity; (h) wherein the source of electromagnetic radiation and the sensors are positioned such that when the membrane strip (41;76) is admitted into the receiving port (45;64), electromagnetic radiation impacts the detection zone (42;82) upon the membrane strip (41;76), and then travels to the sensor; (i) arranging for electromagnetic radiation to proceed through an aperture (54;69) prior to entering the receiving port (45;64);

characterised by
(j) providing a light absorbing member (57;80) within the receiving port (45;64) to absorb stray light, the light absorbing member (57;80) comprising an absorption pad located adjacent the membrane strip (41 ;76) in the receiving port and resting on the upper surface of the membrane strip in use, the absorption pad covering completely the area under which the membrane strip (41;76) is impacted by light from its underside.
Anspruch[fr]
Dispositif de lecture pour dosage à écoulement latéral, le dispositif de lecture étant configuré pour détecter un résultat de dosage depuis une bande de membrane de dosage à écoulement latéral (41 ; 76), le résultat de dosage étant révélé par la liaison d'un analyte détectable au sein d'une zone de détection (42 ; 82) le long de la bande de membrane (41 ; 76), comprenant : (a) un logement (44 ; 73) ayant un extérieur et un intérieur ; (b) un orifice de réception (45 ; 64) au sein du logement pour admettre une bande de membrane directement depuis l'extérieur du logement vers l'intérieur du logement du lecteur, l'orifice de réception fournissant une structure de barrière à la lumière (28 ; 81) ; (c) un mécanisme de lecture comprenant : (i) une source de rayonnement électromagnétique ; (ii) un ou plusieurs capteurs (92) capable(s) de détecter l'intensité du rayonnement électromagnétique, la source de rayonnement électromagnétique et les capteurs (92) étant positionnés au sein du mécanisme de lecture de telle sorte que, lorsque la bande de membrane (41 ; 76) est admise dans l'orifice de réception (45 ; 64), et enfermés par la structure de barrière à la lumière (28 ; 81), le rayonnement électromagnétique vient heurter la zone de détection (42 ; 82) sur la bande de membrane avant de venir heurter le capteur, le rayonnement électromagnétique passant via une ouverture (54 ; 69) avant de pénétrer dans l'orifice de réception, caractérisé en ce que : un élément absorbant la lumière (57 ; 80) est prévu au sein de l'orifice de réception (45 ; 64) pour absorber la lumière perdue, l'élément absorbant la lumière (57 ; 80) comprenant un tampon absorbant situé adjacent à la bande de membrane (41 ; 76) dans l'orifice de réception et reposant sur la surface supérieure de la bande de membrane en service, le tampon absorbant couvrant complètement la zone sous laquelle la bande de membrane (41 ; 76) est heurtée par la lumière depuis sa face inférieure. Dispositif de lecture selon la revendication 1, dans lequel l'orifice de réception (45) comprend une plaque de pression (51) qui porte contre la bande de membrane (41). Dispositif de lecture selon la revendication 2, dans lequel la plaque de pression (51) est chargée par un ressort. Dispositif de lecture selon la revendication 1, dans lequel l'ouverture (69) est allongée. Dispositif de lecture selon la revendication 1, dans lequel l'ouverture (54) est circulaire. Dispositif de lecture selon la revendication 1, dans lequel l'ouverture (54 ; 69) est dimensionnée de façon à avoir une surface qui n'est pas supérieure à environ 1,8 fois la surface de la zone de détection sur la bande de membrane. Dispositif de lecture selon la revendication 1, dans lequel l'ouverture (54 ; 69) est dimensionnée de façon à avoir une surface qui n'est pas supérieure à environ 1,3 fois la surface d'une zone respective sur la bande de membrane. Dispositif de lecture selon l'une quelconque des revendications précédentes, dans lequel l'orifice de réception (45 ; 64) inclut une première position d'arrêt pour une lecture de référence et une seconde position d'arrêt pour une lecture d'échantillon. Kit de test comprenant le dispositif de lecture pour dosage à écoulement latéral selon l'une quelconque des revendications précédentes, réuni à un dispositif de dosage comprenant une bande de membrane poreuse, perméable aux liquides, dans lequel l'épaisseur de la bande de membrane poreuse, perméable aux liquides permet la transmission du rayonnement électromagnétique, le résultat de dosage étant révélé par liaison spécifique d'un analyte détectable directement ou indirectement à un agent de liaison immobilisé dans ladite zone de détection. Kit de test selon la revendication 9, dans lequel le mécanisme de lecture détermine le résultat de dosage en partie en mesurant avec les capteurs le rayonnement électromagnétique réfléchi depuis a) la zone de détection de la bande de membrane et b) une zone d'étalonnage sur la bande de membrane, une comparaison étant faite entre les valeurs mesurées dans a) et b). Système pour mettre en oeuvre un dosage à écoulement latéral pour détecter la quantité d'un analyte se trouvant dans un liquide à tester, le système comprenant . (a) un conjugué sonde-analyte capable de générer un signal détectable ; (b) une bande de membrane, la bande de membrane comprenant une zone de détection sur laquelle est déposée un premier réactif de capture, le premier réactif de capture étant configuré pour fixer les conjugués sonde-analyte pour immobiliser lesdits conjugués sonde-analyte pour former un complexe sandwich au sein de la zone de détection ; et (c) un dispositif de lecture selon l'une quelconque des revendications 1 à 8. Dispositif de lecture; kit de test ou système selon l'une quelconque des revendications précédentes dans lequel l'élément absorbant la lumière (57 ; 80) comprend un matériau feutre qui est souple et conformable. Procédé pour la mise en oeuvre d'un dosage à écoulement latéral pour détecter un analyte se trouvant dans un liquide à tester, procédé qui comprend: (a) la prévision de conjugués sondes sur une bande de membrane (41 ; 76), les conjugués sondes étant configurés pour générer un signal détectable ; (b) la prévision d'un analyte sur la bande de membrane (41 ; 76) ; (c) la fixation entre conjugué sonde et analyte pour former un complexe conjugué sonde-analyte ; (d) dans lequel la bande de membrane (41 ; 76) est configurée pour mobiliser un liquide à tester contenant des sondes et des complexes conjugués sonde-analyte, la bande de membrane (41 ; 76) comprenant une zone de détection (42 ; 82) ; (e) la prévision, dans la zone de détection (42 ; 82), d'un premier réactif de capture, le premier réactif de capture étant immobilisé et configuré pour fixer les complexes conjugués sonde-analyte aux fins de les immobiliser pour former un complexe sandwich au sein de la zone de détection (42 ; 82) ; (f) la fourniture d'un dispositif de lecture, le dispositif de lecture étant configuré pour détecter un résultat de dosage depuis la bande de membrane (41 ; 76), le dispositif de lecture incluant un logement (44 ; 73) ayant un extérieur et un intérieur et un orifice de réception (45 ; 64) ayant une structure de barrière à la lumière (28 ; 81), l'orifice de réception (45 ; 64) étant monté dans le logement pour admettre la membrane directement depuis l'extérieur du logement du lecteur vers l'intérieur du logement du lecteur, le dispositif de lecture comprenant en outre un mécanisme de lecture ayant une source de rayonnement électromagnétique et un ou plusieurs capteurs (92) capables de détecter l'intensité du rayonnement électromagnétique ; (g) le fait d'empêcher la lumière ambiante d'atteindre la zone de détection (42 ; 82) de la membrane, augmentant ainsi la sensibilité ; (h) dans lequel la source de rayonnement électromagnétique et les capteurs sont positionnés de telle sorte que, lorsque la bande de membrane (41 ; 76) est admise dans l'orifice de réception (45 ; 64), le rayonnement électromagnétique vient heurter la zone de détection (42 ; 82) sur la bande de membrane, puis va vers le capteur ; (i) l'agencement du rayonnement électromagnétique de façon qu'il passe via une ouverture (54 ; 69) avant de pénétrer dans l'orifice de réception (45 ; 64) ;

caractérisé par
(j) la fourniture d'un élément absorbant la lumière (57 ; 80) au sein de l'orifice de réception (45 ; 64) pour absorber la lumière perdue, l'élément absorbant la lumière (57 ; 80) comprenant un tampon absorbant situé adjacent à la bande de membrane (41 ; 76) dans l'orifice de réception et reposant sur la surface supérieure de la bande de membrane en service, le tampon absorbant couvrant complètement la zone sous laquelle la bande de membrane (41 ; 76) est heurtée par la lumière depuis sa face inférieure.






IPC
A Täglicher Lebensbedarf
B Arbeitsverfahren; Transportieren
C Chemie; Hüttenwesen
D Textilien; Papier
E Bauwesen; Erdbohren; Bergbau
F Maschinenbau; Beleuchtung; Heizung; Waffen; Sprengen
G Physik
H Elektrotechnik

Anmelder
Datum

Patentrecherche

Patent Zeichnungen (PDF)

Copyright © 2008 Patent-De Alle Rechte vorbehalten. eMail: info@patent-de.com