Common Labeled Types of Antibodies, Better for Immunoassays

Antibody labeling is a common technology used in sample preparation for immunoelectron microscopy. Due to the simple operation, high sensitivity, it is widely used in various immunoassays such as IHC, WB, ICC, ELISA. The labels can amplify the detection signal for antigens, making it a fast and economic detection technology in the market.

Commonly used molecules for antibody labeling include enzymes, fluorescent molecules, isotope, biotin, colloidal gold etc. Below is the introduction of conjugated antibodies from Cloud-Clone Corp.

1. Horseradish peroxidase (HRP) labeling. HRP is conjugated to monoclonal/polyclonal antibody by periodate method. The glycosyl of HRP is oxidized into aldehyde group, which is linked with the amino of antibody and forms the Schiff Base. Common substrates for HRP include o-phenylenediamine (OPD)、tetramethylbenzidine (TMB) and ABTS etc. TMB is the most frequently used substrate in WB and ELISA. The solution changes obviously, from achromic to blue after reacting with HRP; After adding acid to stop the reaction, it becomes yellow and could be quantitative using colorimeter. The detection reagent B in the ELISA kit from Cloud-Clone Corp contains HRP-conjugated substance, which can react with chromogenic substrate TMB.

2. Isothiocyanate (FITC) labeling. FITC is the commonest fluorescein. Under the alkaline condition, isothiocyano from FITC can link to free amino groups of IgG, forming the IgG-fluorescein complex, which can be detected due to the fluorescence. FITC labeled antibody is widely used as a secondary antibody, for single/ multiple staining in IHC. Besides, it can be used in location, qualitative and quantitative detection of antigen, using fluorescence microscope and flow cytometry.

3. Biotin labeling. Currently biotin-avidin system is widely used. Due to the high affinity between biotin and avidin, as well as the cascade amplification, it can be used in quantitative and semi -quantitative detection of antigen by Color Reaction System.

4. Colloidal gold labeling (GICT). Proteins can bind on the surface of colloidal gold by electrostatic adsorption. As colloidal gold has high electron density, dark brown particles can be observed under the microscope. The result can be displayed by color, and it is easy to evaluate by eye without any equipment. It is suitable for basic units, hospitals, field operation and remote region, etc. Cloud-Clone Corp. are developing this technology and colloidal gold labeled antibody can to be offered to researchers soon.

5. Chemiluminescent labeling. Antibody can be directly labeled by chemiluminescent agent such as luminol. It can be detected by enhanced ECL chemiluminescence system, which is the substrate of luminol. The chemiluminescence kits from Cloud-Clone Corp. is developed by this technology.

Cloud-Clone Corp. have rich experience in producing antigens and antibodies, with mature technology for antibody labeling. Researchers can purchase various labeled antibodies from us. Below are some common labeled antibodies.