Patent Application
20100047799
The present invention refers to an immuno-chromatographic detection cup and its use for simultaneously detecting at least one antigen, e.g. tuberculosis antigen, malaria antigen and pneumonia antigen, and at least one antibody, e.g. HIV antibody, HCV antibody and H. pylori antibody, in a urine sample. The detection makes use of gold-labelled antibodies and antigens, oligo-nucleotide linked antibodies and antigens, and complementary oligo-nucleotides for capturing the linked antibodies.
Testing for HIV is an essential component in the diagnosis and treatment of persons infected with the virus, in screening of blood for transfusion, in surveillance and in HIV/AIDS related research. Thus, accurate and cost-effective testing is of great importance in combating the spread of HIV. It is imperative that tests for the diagnosis of HIV infection should be as accurate as possible, given the serious ethical, legal and social issues that accompany HIV infection1.
The use of body fluids other than blood as specimens for detecting antibodies to HIV has been reported to have potential as an alternative medium for HIV testing. The use of urine samples may be attractive due to the ease of sample collection, possible cost savings, better safety (against needle stick injuries) and higher compliance rates. Assays for these types of specimens can be a useful alternative when it is difficult or impossible to test for HIV in blood samples. It may be that blood can not be drawn for religious reasons or difficulties may be experienced in collecting blood samples in hard to reach places where it is, nevertheless, important to have epidemiological surveillance1. Moreover, urinary samples are the more safety type of specimens in case of HIV infection.
Today, new HIV tests have been developed for use with urine specimens. Urine contains very low levels of IgG, frequently around 1 mg/l, and therefore very sensitive techniques are required to detect specific antibody. Thus, to date, the tests for urine specimens have been based on ELISA and Western blot techniques, however, efforts are being made to develop simple and/or rapid tests for the detection of antibody to HIV in urine specimens1. It would be of particular advance to have rapid immuno-chromatographic test devices available for detecting HIV antibodies in urine.
In addition to HIV infection, tuberculosis (TB) is an important and increasing public health problem in both industrialized and developing countries. Hence, the development of new inexpensive, rapid and field adapted methods for its diagnosis is urgently needed. Sputum culture, which is still the reference method for the diagnosis of pulmonary TB, is cumbersome and time-consuming, and requires access to expensive biosafety level 3 (BSL3) laboratories. Microscopy of direct smears for acid-fast bacilli (AFB) as recommended by WHO for developing countries is the most commonly used method for diagnosis of TB. A major disadvantage with this method is its low sensitivity, even after concentration of the sputum samples.
The availability of new field adapted, low-cost, and rapid diagnostic tests to supplement AFB microscopy, and especially methods improving the diagnosis in AFB-negative disease, would be of great benefit for TB control programs, in particular in areas lacking appropriate safety laboratories. Among the newly developed methods for rapid diagnosis of TB, nucleic acid amplification methods such as PCR seem most promising, but the technology is still too complex to be feasible for TB control programs in developing countries. Antibodies against a number of mycobacterial antigens have been identified in patients using a variety of immunological techniques, but no antibody test has so far reached sufficient sensitivity and/or specificity for routine diagnostic purposes. Detection of circulating or secreted Mycobacteriurm tuberculosis antigens seems attractive and has been explored in a number of studies. However, no satisfactory commercial test for mycobacterial antigens in serum or sputum is currently available.
The idea of identifying mycobacterial antigens in urine of TB patients is attractive for several reasons: urine is more readily obtainable than serum samples and urinary specimens do not carry the risks inherent to needles and blood-based laboratory work. Furthermore, if the urine specimens are boiled before handling, there is no need for BSL3 facilities.
In 1920s, mycobacterial antigens were detected in the urine of TB patients, and the diagnostic potential of such antigens was subsequently discussed by other scientists. More recently, the diagnostic value of mycobacterial antigens in the urine of leprosy patients has been assessed. Unfortunately, the techniques involved turned out to be insufficiently sensitive in paucibacillary patients, the patient group where improved diagnostic tests are needed most
Lipoarabinomannan (LAM) is a major and structurally important glycolipid component of the outer cell wall of all mycobacteria and may account for up to 15% of the total bacterial weight. LAM is a carbohydrate antigen with glycosidic linkages for which no human degrading glycosidases are known. Hence, we assumed that in active mycobacterial disease LAM may be cleared through the kidneys and occur in urine in antigenically intact form. Furthermore, since LAM is a carbohydrate antigen and thus inherently heat-stable, LAM may be detectable by sensitive immunological techniques even after boiling of the urine. At least theoretically, the amount of LAM in the urine should reflect the bacterial load, metabolic activity and/or rate of degradation of the bacteria, and hence permit a semi-quantitative assessment of the infectious status. A high sensitive, simple, fast and reliable method for LAM detection and quantification was reported using an enzyme-linked immunosorbent assay (ELISA) in AFB positive sputa from TB patients2. However, it would be of particular advantage to have rapid immuno-chromatographic test devices available for detecting LAM in urine.
In recent years, the in vitro diagnostics (IVD) industry has made enormous efforts to develop immuno-chromatographic tests. Such tests have found applications in both clinical and non-clinical fields3. A clinical utility of this test format has been shown for more than 150 different analytes, and many of them are target now of commercially available diagnostic products4. The wide range of applications for such devices has been reviewed3, 5.
Rapid immuno-chromatographic test devices, e.g. in the form of a test strip, are made up of a number of components (see
Using rapid immuno-chromatographic test devices, a physician can instantly not only examine a sample by himself, but also diagnose a patient on the basis of the obtained results. Such test devices for diagnostic purposes are easy to operate and thus do not only contribute to the comfort of professional users, e.g. medical stuff, but also allow the operation by non-professionals users, e.g. most patients.
However, a main demerit is that one immuno-chromatographic test device only detects one parameter at a time with the consequence that many different rapid immuno-chromatographic test devices are needed to check the suspected parameters, resulting in the requirement of enormous sample volume to be obtained from a patient as well as cumbersome test procedures.
Therefore, it is an object of the present invention to provide a rapid immuno-chromatographic test device for detecting different analytes (antibodies and antigens) in urine in a single assay at the same time.
The object of the present invention is solved by a urinary immuno-chromatographic detection cup comprising:
Antibodies X and X′ may be identical or different, as long as they are directed against the same antigen. Antigens Y and Y′ may be identical or different as long as they are recognized by the same antibody;
In one embodiment, the antibodies X and X′ are directed against an antigen selected from tuberculosis antigen, malaria antigen and pneumonia antigen.
In a preferred embodiment, the tuberculosis antigen is LAM, the malaria antigen is HRP-II, and the pneumonia antigen is PLY.
In one embodiment, the control antibody is anti-mouse IgG.
In one embodiment, the antigens Y and Y′ are selected from envelop protein gp 160 from HIV, NS3 antigen from HCV, and H. pylori antigen.
In one embodiment, the test device further comprises a nitrocellulose membrane on which the complementary oligo-nucleotides are immobilized.
In one embodiment, the conjugate releasing pad is located at the internal surface of the container wall.
In one embodiment, a first sample absorbent pad is located at the bottom, and a second sample pad is located at the top of the container.
In a preferred embodiment, the sample absorbent pad at the top is fitted into a container cap.
In a further preferred embodiment, the sample absorbent pad at the top has a capacity of absorbing at least 15 ml of sample.
In one embodiment, the conjugate releasing pad further comprises optionally modified chitosan.
The object of the present invention is further solved by a use of the urinary immuno-chromatographic detection cup according to the present invention for detecting at least one antigen selected from tuberculosis antigen, malaria antigen and pneumonia antigen in a sample of urine of a subject, preferably human, and at least one antibody selected from HIV antibody, HCV antibody and H. pylori antibody.
In one embodiment of the use, the volume of the urine sample is approximately 15 ml.
The object of the present invention is further solved by a method for preparing the urinary fluid immuno-chromatographic detection cup according to the present invention, wherein optionally modified water-soluble chitosan is added during the preparation of gold labelled antibody X or gold labelled antigen Y prior to conjugation of colloid gold with the antibody or antigen.
In one embodiment of the method, the colloidal gold is prepared by reduction of 1% aqueous solution of tetra-chloroauric acid using tri-sodium citrate aqueous solution to produce spheroidal gold particles.
The object of the present invention is also solved by a urinary immuno-chromatographic detection cup comprising:
The object of the present invention is also solved by a urinary immuno-chromatographic detection cup comprising:
The object of the present invention is also solved by a urinary immuno-chromatographic detection cup comprising:
In one embodiment, the two antibodies are directed against two different antigens selected from tuberculosis antigen, malaria antigen and pneumonia antigen.
In a preferred embodiment, the tuberculosis antigen is LAM, the malaria antigen is HRP-II, and the pneumonia antigen is PLY.
In one embodiment, the control antibody is anti-mouse IgG.
In one embodiment, the two different antigens are selected from envelop protein gp 160 from HIV, NS3 antigen from HCV, envelop antigen from HCV, and H. pylori antigen,
In one embodiment, the test device further comprises a nitrocellulose membrane on which the complementary oligo-nucleotides are immobilized.
In one embodiment, the conjugate releasing pad is located at the internal surface of the container wall.
In one embodiment, a first sample absorbent pad is located at the bottom and a second sample pad is located at the top of the container.
In a preferred embodiment, the sample absorbent pad at the top is fitted into a container cap.
In a particularly preferred embodiment, the sample absorbent pad at the top has a capacity of absorbing at least 15 ml of sample.
In one embodiment, the conjugate releasing pad further comprises optionally modified chitosan.
The object of the present invention is further solved by a use of the urinary immuno-chromatographic detection cup according to the present invention for detecting at least two different antigens selected from tuberculosis antigen, malaria antigen and pneumonia antigen in a sample of urine of a subject, preferably human.
In a preferred embodiment, the tuberculosis antigen is LAM, the malaria antigen is HRP-II, and the pneumonia antigen is PLY.
The object of the present invention is further solved by a use of the urinary immuno-chromatographic detection cup according to the present invention for detecting at least two different antibodies selected from HIV, HCV and H. pylori antibody in a sample of urine of a subject, preferably human.
The object of the present invention is further solved by a use of the urinary immuno-chromatographic detection cup according to the present invention for detecting at least one antigen selected from tuberculosis antigen, malaria antigen and pneumonia antigen in a sample of urine of a subject, preferably human, and at least one antibody selected from HIV, HCV and H. pylori antibody
In one embodiment, the volume of the urine sample is approximately 15 ml.
The object of the present invention is further solved by a method for preparing the urinary fluid immuno-chromatographic detection cup according to the present invention, wherein optionally modified water-soluble chitosan is added during the preparation of gold labelled antibody or antigen prior to conjugation of colloid gold with the antibody or antigen.
In one embodiment, the colloidal gold is prepared by reduction of 1% aqueous solution of tetra-chloroauric acid using tri-sodium citrate aqueous solution to produce spheroidal gold particles.
Thus, the present invention provides a urinary multi-parameter rapid immuno-chromatographic detection cup using a unique system for the detection of at least one antigen and/or at least one antibody in a single assay at the same time. This is achieved by using (1) colloidal gold-labelled antibodies and oligo-nucleotide-linked antibodies, and (2) colloidal gold-labelled antigens and oligo-nucleotide-linked antigens. The oligo-nucleotide-linked anti-bodies and/or antigens are captured by complementary oligo-nucleotides.
One of the advantages of the test device of the present invention is that there is no requirement for the preparation of different rapid immuno-chromatographic test devices to check more than one parameter. Another advantage is that the patient's sample is readily obtainable by non-invasive procedures, namely urine.
High sensitivity of measurements carried out in urine by means of the test device of the present invention is achieved by using a large volume of urine as a sample (about 15 ml urine instead of 17 μl of serum; concentration of IgG in urine is about 1:6000; factor reduction to 1:7) and by using water-soluble chitosan (or modified water-soluble chitosan) as a colour intensity modification agent.
a shows an assembly comprising a test strip 201, an absorbent sample pad 202, and an absorbent pad 205.
b shows an immuno-chromatographic detection cup comprising a sample-collecting container 210, a cap 211, and the assembly shown in
a shows an assembly comprising a test strip 101, an absorbent sample pad 102, a nitrocellulose membrane 104, a conjugate pad 103, an adhesive 106, a supporting backing 107, a control zone 109, and an absorbent pad 105. The conjugate pad 103 contains the gold-labelled antibody 302, oligonucleotide 1 labelled antibody 304, gold labelled antigen 303, oligonucleotide 2 labelled antigen 301. Capturing complementary oligo-nucleotide 1′ and 2′ are immobilized within sample zone(s) 305 and 306, respectively, onto the nitrocellulose membrane 104.
b shows the detection test strip of
One embodiment of the rapid immuno-chromatographic detection system of the present invention is shown in
A gold conjugate releasing pad 203 is fixed to the internal surface of the container wall which pad 203 comprises (1a) colloidal gold-labelled antibodies and (1b) oligo-nucleotide-linked antibodies, and (2a) colloidal gold-labelled antigens and (2b) oligo-nucleotide-linked antigens. The gold conjugates will begin releasing from the pad 203 during the urine sample is streaming into the container 210. Release into the sample will increase the possibility of interaction between the conjugates and the analytes, e.g. antibodies and/or antigens.
Capturing complementary oligo-nucleotides are immobilized within one or more sample zones 208 onto the nitrocellulose membrane 204 (see also
Non-specific antibody and/or antigen is immobilized as a control zone 209 onto the nitrocellulose membrane 204 for non-specific capturing of the gold conjugates (see also
The antigens used may be synthetic or recombinant. The antibodies used may be polyclonal or monoclonal. In the embodiment shown in
Detection of the following diseases is taken into consideration:
The preparation of oligo-nucleotide-labelled antibody Fab′ comprises the following steps6:
The preparation of oligo-nucleotide-labelled protein comprises the following steps7:
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-LAM, oligo-nucleotide 1 linked anti-LAM, gold labelled recombinant envelop protein gp160, oligo-nucleotide 2 linked recombinant envelop protein gp160. A first sample zone 208 (tuberculosis antigen=LAM specific detection zone) comprises complementary oligo-nucleotide 1′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (HIV antibody specific detection zone) comprises complementary oligo-nucleotide 2′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG and goat anti-gp160. The first sample zone 208 and control zone 209 turn into purple colour in case that tuberculosis antigen (LAM) is present in the sample, and the second sample zone 208 and control zone 209 turn into purple colour in case that HIV antibody (anti-gp160) is present in the sample; only the control zone turns into purple colour in case of HIV antibody and tuberculosis antigen free sample.
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-HRP-II, oligo-nucleotide 3 linked anti-HRP-II, gold labelled recombinant envelop protein gp160, oligo-nucleotide 2 linked recombinant envelop protein gp160. A first sample zone 208 (malaria antigen=HRP-II specific detection zone) comprises complementary oligo-nucleotide 3′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (HIV antibody specific detection zone) comprises complementary oligo-nucleotide 2′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG and goat anti-gp160. The first sample zone 208 and control zone 209 turn into purple colour in case that malaria antigen (HRP-II) is present in the sample, and the second sample zone 208 and control zone 209 turn into purple colour in case that HIV antibody (anti-gp160) is present in the sample; only the control zone turns into purple colour in case of HIV antibody and malaria antigen free sample.
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-LAM, oligo-nucleotide 1 linked anti-LAM, gold labelled anti-HRP-II, oligo-nucleotide 3 linked anti-HRP-II, gold labelled recombinant envelop protein gp160, and oligo-nucleotide 2 linked recombinant envelop protein gp160. A first sample zone 208 (tuberculosis antigen=LAM specific detection zone) comprises complementary oligo-nucleotide 5′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (malaria antigen=HRP-II specific detection zone) comprises complementary oligo-nucleotide 3′ immobilized onto the nitrocellulose membrane. A third sample zone 208 (HIV antibody specific detection zone) comprises complementary oligo-nucleotide 2′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG and goat anti-gp160. The first sample zone 208 and control zone 209 turn into purple colour in case that tuberculosis antigen (LAM) is present in the sample, the second sample zone 208 and control zone 209 turn into purple colour in case that malaria antigen (HRP-II) is present in the sample, and the third sample zone 208 and control zone 209 turn into purple colour in case that HIV antibody (anti-gp160) is present in the sample; only the control zone turns into purple colour in case of HIV antibody, tuberculosis antigen and malaria antigen free sample.
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-HRP-II, oligo-nucleotide 3 linked anti-HRP-II, gold labelled recombinant HCV NS3 antigen, oligo-nucleotide 4 linked HCV NS3 antigen. A first sample zone 208 (malaria antigen=HPR-II specific detection zone) comprises complementary oligo-nucleotide 3′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (HCV NS3 antibody specific detection zone) comprises complementary oligo-nucleotide 4′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG and goat anti-HCV NS3 antigen. The first sample zone 208 and control zone 209 turn into purple colour in case that malaria antigen (HRP-II) is present in the sample, and the second sample zone 208 and control zone 209 turn into purple colour in case that HCV antibody (anti-NS3) is present in the sample; only the control zone turns into purple colour in case of HCV NS3 antibody and malaria antigen free sample.
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-LAM, oligo-nucleotide 1 linked anti-LAM, gold labelled recombinant HCV NS3 antigen, oligo-nucleotide 4 linked HCV NS3 antigen. A first sample zone 208 (tuberculosis antigen=LAM specific detection zone) comprises complementary oligo-nucleotide 1′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (HCV NS3 antibody specific detection zone) comprises complementary oligo-nucleotide 4′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG and goat anti-HCV NS3 antigen. The first sample zone 208 and control zone 209 turn into purple colour in case that tuberculosis antigen (LAM) is present in the sample, and the second sample zone 208 and control zone 209 turn into purple colour in case that HCV NS3 antibody is present in the sample; only the control zone turns into purple colour in case of HCV NS3 antibody and tuberculosis antigen free sample.
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-HRP-II, oligo-nucleotide 3 linked anti-HRP-II, gold labelled recombinant HCV NS3 antigen, oligo-nucleotide 4 linked HCV NS3 antigen, gold labelled recombinant envelop protein gp160, and oligo-nucleotide 2 linked recombinant envelop protein gp160. A first sample zone 208 (malaria antigen=HRP-II specific detection zone) comprises complementary oligo-nucleotide 3′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (HCV NS3 antibody specific detection zone) comprises complementary oligo-nucleotide 4′ immobilized onto the nitrocellulose membrane. A third sample zone 208 (HIV gp160 antibody specific detection zone) comprises complementary oligo-nucleotide 2′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG, goat anti-HCV NS3 antigen and goat anti-gp160. The first sample zone 208 and control zone 209 turn into purple colour in case that malaria antigen (HPR-II) is present in the sample, the second sample zone 208 and control zone 209 turn into purple colour in case that HCV antibody (anti-NS3) is present in the sample, and the third sample zone 208 and control zone 209 turn into purple colour in case that HIV antibody (anti-gp160) is present in the sample; only the control zone turns into purple colour in case of HCV NS3 antibody, HIV gp160 antibody and malaria antigen (HRP-II) free sample.
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-LAM, oligo-nucleotide 1 linked anti-LAM, gold labelled recombinant HCV NS3 antigen, oligo-nucleotide 4 linked HCV NS3 antigen gold labelled recombinant envelop protein gp160, and oligo-nucleotide 2 linked recombinant envelop protein gp160. A first sample zone 208 (tuberculosis antigen=LAM specific detection zone) comprises complementary oligo-nucleotide 1′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (HCV NS3 antibody specific detection zone) comprises complementary oligo-nucleotide 4′ immobilized onto the nitrocellulose membrane. A third sample zone 208 (HIV gp160 antibody specific detection zone) comprises complementary oligo-nucleotide 2′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG, goat anti-HCV NS3 antigen and goat anti-gp160. The first sample zone 208 and control zone 209 turn into purple colour in case that tuberculosis antigen (LAM) is present in the sample, the second sample zone 208 and control zone 209 turn into purple colour in case that HCV antibody (anti-NS3) is present in the sample, and the third sample zone 208 and control zone 209 turn into purple colour in case that HIV antibody (anti-gp160) is present in the sample; only the control zone turns into purple colour in case of HCV antibody (anti-NS3), HIV antibody (anti-gp160) and tuberculosis antigen (LAM) free sample.
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-LAM, oligo-nucleotide 1 linked anti-LAM, gold labelled anti-HRP-II, oligo-nucleotide 3 linked anti-HRP-II, gold labelled recombinant HCV NS3 antigen, oligo-nucleotide 4 linked HCV NS3 antigen, gold labelled recombinant envelop protein gp160, and oligo-nucleotide 2 linked recombinant envelop protein gp160. A first sample zone 208 (tuberculosis antigen=LAM specific detection zone) comprises complementary oligo-nucleotide 1′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (malaria antigen=HRP-II specific detection zone) comprises complementary oligo-nucleotide 3′ immobilized onto the nitrocellulose membrane 204. A third sample zone 208 (HCV NS3 antibody specific detection zone) comprises complementary oligo-nucleotide 4′ immobilized onto the nitrocellulose membrane. A fourth sample zone 208 (HIV gp160 antibody specific detection zone) comprises complementary oligo-nucleotide 2′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG, goat anti-HCV NS3 antigen and goat anti-gp160. The first sample zone 208 and control zone 209 turn into purple colour in case that tuberculosis antigen (LAM) is present in the sample, the second sample zone 208 and control zone 209 turn into purple colour in case that malaria antigen (HRP-II) is present in the sample, the third sample zone 208 and control zone 209 turn into purple colour in case that HCV antibody (anti-NS3) is present in the sample, and the fourth sample zone 208 and control zone 209 turn into purple colour in case that HIV antibody (anti-gp160) is present in the sample; only the control zone turns into purple colour in case of HCV antibody, HIV antibody, malaria antigen and tuberculosis antigen free sample.
The conjugate releasing pad 203 immobilized onto the internal surface of the sample-collecting container 210 comprises gold labelled anti-LAM, oligo-nucleotide 1 linked anti-LAM, gold labelled anti-pneumolysin (PLY), oligo-nucleotide 5 linked anti-pneumolysin (PLY), and gold labelled H. pylori antigen, oligo-nucleotide 6 linked H. pylori antigen. A first sample zone 208 (tuberculosis antigen=LAM specific detection zone) comprises complementary oligo-nucleotide 1′ immobilized onto the nitrocellulose membrane 204. A second sample zone 208 (pneumonia antigen=PLY specific detection zone) comprises complementary oligo-nucleotide 5′ immobilized onto the nitrocellulose membrane. A third sample zone 208 (H. pylori antibody specific detection zone) comprises complementary oligonucleotide 6′ immobilized onto the nitrocellulose membrane. The control zone 209 comprises a mixture of anti-mouse IgG, and goat anti-H. pylori antigen. The first sample zone 208 and control zone 209 turn into purple colour in case that tuberculosis antigen (LAM) is present in the sample, the second sample zone 208 and control zone 209 turn into purple colour in case that Pneumonia antigen (PLY) is present in the sample, and the third sample zone 208 and control zone 209 turn into purple colour in case that H. pylori antibody is present in the sample; only the control zone turns into purple colour in case of H. pylori antibody, tuberculosis antigen and Pneumonia antigen free sample.
The colloidal gold conjugate colour intensity was amplified using water-soluble chitosan (or modified water-soluble chitosan) as a colour intensity modification agent. The action of water-soluble chitosan (or modified water-soluble chitosan) in connection with the antibodies or antigens is on the colour intensity of the colloidal gold. Chitosan is added during the preparation of colloidal gold, but prior to the conjugation of colloidal gold with the antibodies or the antigens. Water-soluble chitosan (or modified water-soluble chitosan) affect the colour intensity of colloidal gold and so increases the ability of the human eye to identify the colour, and, thus, enables to detect very low concentrations of the analyte. Signal amplification lies in the range of up to 10 folds. Colloidal gold could be prepared by the reduction of 1% aqueous solution of tetra-chloroauric acid (HAuCl4) using tri-sodium citrate aqueous solution to produce spheroidal gold particles. After colloidal gold preparation, water-soluble chitosan (or modified water-soluble chitosan) aqueous solution was added with a suitable volume and concentration to convert colour from purple to violet pending on the volume and concentration of the added modification solution.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06025531.2 | Dec 2006 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2007/010611 | 12/6/2007 | WO | 00 | 10/26/2009 |
