Views: 0 Author: Site Editor Publish Time: 2022-05-20 Origin: Site
The colloidal gold immune technology of the Antigen test utilizes the high electron density of gold particles and uses colloidal gold as a tracer marker for immunoassays. Colloidal gold labeling is essentially the coating process of adsorbing proteins and other macromolecules on the surface of colloidal gold particles. Colloidal gold immunological techniques include immuno-colloidal gold light microscopy staining, immuno-colloidal gold electron microscopy staining, spot immunogold percolation method, and colloidal gold immunochromatography. So what is the colloidal gold immune technology and the prospect of an Antigen test? Let's take a look at it next.
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l Colloidal gold immunoassay technology of Antigen test
At present, the main method used in the Antigen test kit is colloidal gold immunochromatography, including the approved IgM and IgG antibody detection kits. The colloidal gold immunochromatographic technique detects antibodies indirectly. The specific antigen I labeled with colloidal gold is adsorbed on the gold label pad, the specific antigen II is immobilized on the detection area (T line), and the specific antigen II is immobilized on the quality control area (Cline). Antibody against specific antigen I. The sample is dropped on the sample pad, the antibody to be tested passes through the gold-labeled pad, and the formed antibody-gold-labeled antigen binds to the antigen II at the T line, and the free gold-labeled antigen I continues to move forward to the C-line to combine with the anti-antibody, and finally, the T-line and the C-line will have varying degrees of color change. The Antigen test replaces the gold-labeled antigen I and the antigen II immobilized in the detection area with specific antibodies that can bind to viral antigens. The technology has now been developed into the form of diagnostic test strips, which are very convenient to use. When carrying out the Antigen test for the new coronavirus, use venous whole blood, serum, or plasma samples to mix with diluent, add directly to the sample pad, wait for 10 to 15 minutes, and then the color of the test line and the control line on the test strip can be used critical result. Positive if both the test strip and the control line turn red; if the test strip does not change color and the control strip is red, it is negative. The colloidal gold immunoassay technology is simple to operate, does not require additional instruments for qualitative analysis, and can perform comprehensive or separate detection of IgG and IgM; it has advantages compared with the relatively cumbersome enzyme-linked immunosorbent assay, and the reaction is rapid; However, the sensitivity of this technique is relatively poor and quantitative detection cannot be performed. At present, the colloidal gold immunochromatographic analysis kits of many companies have been approved and listed on the market in an emergency, which is suitable for rapid screening of clinically suspected cases, especially in places where there are no supporting detection instruments required for other immunoassays.
Immunodiagnostic techniques for viruses include antibody detection and antigen detection, which are all based on immune responses. Antigen test requires the preparation of antibodies (monoclonal antibodies or polyclonal antibodies) that specifically bind to viral proteins, which are usually prepared by immunizing animals. The preparation process is complicated and takes a long time. Antibody detection requires antigens that can be combined with antibodies produced by immune responses. Compared with the immune collection and purification of antibodies, recombinant antigen expression, and purification technology is relatively simple and has a relatively short period; therefore, the currently successfully developed COVID-19 rapid the number of Antigen test kits is much more than other Antigen test kits, and the immunodiagnostic kits approved for the market are also antibody detection kits. However, there are no detectable antibodies in the serum at the early stage of the disease, so the antibody test cannot screen the infected people at this stage; at this time, if you want to screen by immunological methods, you need to use an Antigen test, which can be developed and approved as soon as possible. Antigen kits for clinical diagnosis have become very important.
The above is about the colloidal gold immunological technology and the prospect of an Antigen test. If you are interested in the Antigen test, you can contact us. Our website is www.bioteke.cn.