News Column

Patent Application Titled "Chromatography Filter Paper-Based Elisa" Published Online

July 31, 2014

By a News Reporter-Staff News Editor at Politics & Government Week -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors HSU, Min-Yen (Hsinchu, TW); LIN, Keng-Hung (Hsinchu, TW); CHENG, Chao-Min (Hsinchu, TW), filed on April 22, 2013, was made available online on July 17, 2014.

The assignee for this patent application is National Tsing Hua University.

Reporters obtained the following quote from the background information supplied by the inventors: "The present invention relates to a chromatography filter paper-based ELISA and more particularly to a chromatography filter paper-based ELISA for lesion analysis of ocular angiogenesis.

"As society grows wealthier and life expectancy of human increases, diseases of civilization such as diabetic retinopathy and macular degeneration become threats to humans' health. According to statistics, there are approximately more than one million of people suffering from macular degeneration in the U.S.A. These two diseases have been proved highly relevant to concentration of vascular endothelial growth factor (VEGF) in eyes. When the concentration of VEGF increases, lesions of diabetic retinopathy or macular degeneration become worse and may even lead to blindness.

"In order to cope with these diseases, at least two types of antibody drugs are developed against VEGF. The older version is Bevacizumab (Avastin) and the newer one is ranibizumab (lucentis), wherein the latter one is modified based on the older version and provided with less molecular weight. Both of these drugs are used to reduce the concentration of VEGF in eyes so as to reduce vascular proliferation and prevent deterioration in vision.

"However, due to complexity and specialization of the nervous structure of the eyes, general blood testing is not applicable to assess lesion activity of eye diseases. Besides, there is no suitable method to sample eyes fluid for analysis of the growth factors in lesions. Therefore, ocular lesions become a conundrum to be solved since the VEGF concentration cannot be traced by molecular testing so far.

"Enzyme-linked immunosorbent assay (ELISA) is a test to detect the presence of a substance and has been used in various industries. Based on the special binding properties between antigens and antibodies, the specific antibodies added can bind to the antigens of the sample. Subsequently, a substrate of the enzyme is added and displays color change. Based on colorimetric reaction of the enzyme, it can be determined whether the antigens bind with the antibodies for qualitative analysis. Additionally, the degree of combination of the antigens and antibodies may yield color intensity for quantitative analysis.

"Traditionally, a 96-well microplate (manufactured by plastic injection molding) is used for ELISA. It is adequate for quantitative analysis and high-throughput screening. Nevertheless, analyte and reagents of each test requires relatively large volume (approx. 20.about.200 .mu.l) and long time for operation. It still needs to be improved.

"Dot-immunobinding assays (DIA) uses porous membranes of nitrocellulose filter paper. Although DIA allows simple immunoassay performed on the paper, each test consumes a new piece of nitrocellulose filter paper and needs to be treated individually in the petri dish for few hours. Currently, most DIA are considered qualitative tests but not quantitative tests, which only provides Yes/No results.

"U.S. Pat. No. 7,083,912 discloses a Dot-ELISA for detecting viruses. It uses nitrocellulose and monoclonal antibodies to promote detection sensibility. Mainly, it contributes to qualitative detection but not quantitative detection.

"In brief, it is a difficult challenge to monitor VEGF concentration from the anterior chamber of eyeballs according to present techniques. The maximum amount of aqueous humor which can be extracted from the anterior chamber of eyeballs is 0.2 mL and each well of a 96-well microplate requires around 0.1 mL of aqueous humor. As a result, a single traditional ELISA test (maximum for two times) can be performed once for each patient and cannot be repeated for many times to obtain more precise clinical information.

"Hence, there remains a need in the art to develop a rapid analysis provided with higher sensibility and only requiring lower amount of loaded sample for ELISA."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "It is an object of the present invention to provide a chromatography filter paper-based ELISA, which has advantages in lower amount of loaded sample, higher sensitivity and rapid analysis.

"According to one embodiment of the present invention, a chromatography filter paper-based ELISA, comprising: providing a chromatography filter paper plate having a plurality of independent hydrophilic regions defined by at least one hydrophobic region; immobilizing an antigen of a sample onto one of the hydrophilic regions of the chromatography filter paper plate; and detecting the antigen with an ELISA, wherein a monoclonal antibody is used in the ELISA.

"The objective, technologies, features and advantages of the present invention will become apparent from the following description in conjunction with the accompanying drawings wherein certain embodiments of the present invention are set forth by way of illustration and example.


"FIG. 1 is a flowchart schematically illustrating the steps of the chromatography filter paper-based ELISA of the present invention;

"FIG. 2 is a schematic diagram illustrating a chromatography filter paper plate according to an embodiment of the present invention;

"FIGS. 3A and 3B are diagrams of the experimental data displaying sensitivity of the chromatography filter paper-based ELISA according to an embodiment of the present invention;

"FIG. 4A to FIG. 4E are photos displaying ocular vascular lesions of diabetic retinopathy patients;

"FIG. 5A to 5F are photos displaying ocular vascular lesions of age-related macular degeneration patients;

"FIG. 6A to 6F are photos displaying ocular vascular lesions of retinal vein occlusion patients; and

"FIG. 7A to 7B are photos displaying ocular vascular lesions of age-related macular degeneration patients before and after treatments."

For more information, see this patent application: HSU, Min-Yen; LIN, Keng-Hung; CHENG, Chao-Min. Chromatography Filter Paper-Based Elisa. Filed April 22, 2013 and posted July 17, 2014. Patent URL:

Keywords for this news article include: Antibodies, Antigens, Biological Factors, Blood Proteins, Diabetes, Endocrinology, Immunoglobulins, Immunology, National Tsing Hua University.

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Source: Politics & Government Week

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