Colloidal gold is a commonly used labeling technology. It is a new type of immunolabeling technology that uses colloidal gold as a tracer marker and is applied to antigen and antibody. It has its unique advantages. It has been widely used in various biological researches in recent years. Almost all immunoblotting techniques used in clinical use its markers. Colloidal gold test may be used in flow, electron microscopy, immunology, molecular biology and even biochips.
Cell suspension smears or tissue sections can be stained with colloidal gold-labeled antibodies, or on the basis of colloidal gold labeling, the silver developing solution can be used to enhance the labeling, so that the reduced silver atoms are deposited on the surface of the labeled gold particles, which can significantly enhance the sensitivity of colloidal gold labeling.
Colloidal gold-labeled antibodies or anti-antibodies can be combined with negatively stained virus samples or tissue ultrathin sections, and then negatively stained. Electron microscope staining colloidal gold method can be used for the observation of virus morphology and virus detection.
Use a microporous membrane (such as a membrane) as a carrier, first spot the antigen or antibody on the membrane, add the sample to be tested after blocking, and use colloidal gold-labeled antibody to detect the corresponding antigen or antibody after washing.
The specific antigen or antibody is fixed on the membrane in a strip shape, and the colloidal gold test reagent is adsorbed on the binding pad. When the sample to be tested is added to the sample pad at one end of the test strip, it moves forward by capillary action and dissolves the binding pad. The colloidal gold-labeled reagent reacts with each other, and when it moves to the area of the fixed antigen or antibody, the conjugate of the object to be tested and the gold-labeled reagent binds specifically to it and is trapped, and accumulates on the detection zone. Color development results were observed with the naked eye. The method has now been developed into a diagnostic test strip, which is very convenient to use.
It is to fix the specific antibody on a certain zone of the acid cellulose membrane. When one end of the dry acid cellulose is immersed in the sample (urine or serum), the sample will move forward along the membrane due to capillary action. When it moves to the area where the antibody is immobilized, the corresponding antigen in the sample specifically binds to the antibody. At the same time, the gold particles have the characteristics of high electron density at the binding site of the gold-labeled protein. When these markers aggregated in large numbers at the corresponding ligands, red spots were visible to the naked eye. It is the principle of fast gold-labeled colloidal gold method. The production of fast and accurate reagents depends on whether the sensitivity and specificity of the raw materials such as monoclonal antibodies, polyclonal antibodies, antigens, haptens, protein chimeras and colloidal gold can reach the highest standard, which is the most important criterion for the quality of gold-labeled reagents.