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Common IVD reagent raw materials

The immunochromatographic technique uses a strip of fibrous layer material as the solid phase, and causes the sample solution to swim on the chromatographic material through capillary action, at the same time causes a specific immune reaction between the antigen/antibody in the sample labeled by the marker and the antigen/antibody encapsulated on the chromatographic material, which is enriched on the detection line, and then achieves the detection purpose through the color of the marker or the photoelectromagnetic signal amplification effect. This technique is the most common type of POCT product because of its low test cost and easy for use.

The main methods of immunochromatographic techniques include colloidal gold immunochromatography and fluorescence immunochromatography. Colloidal gold immunochromatography can directly discriminate the results with the naked eye and perform qualitative or semi-quantitative analysis; fluorescence immunochromatography requires the detection of fluorescence signals by supporting instruments and then perform qualitative or quantitative analysis.

By encapsulating the capture antibody (antigen) in a nitrocellulose membrane, the colloidal gold antibody (antigen) is the basic structure of a colloidal gold test strip is composed of a nitrocellulose membrane coated with a capture antibody (antigen), a colloidal gold antibody (antigen) coated with a labeling pad, a sample pad and an absorbent pad.


The performance of the reagent strip depends on the selection of the antigen/antibody, the stability of the colloidal gold labeling process, and the optimization of the sample pad formulation.

The main function of sample pad is to improve the homogeneity and controllability of sample chromatography, and a cellulose-like filter membrane is widely used.

Conjugated release pad as a carrier for colloidal gold attachment, it needs to have low non-specific adsorption capacity and homogeneous chromatographic performance, commonly used are glass fiber membrane, polypropylene plastic, polyethylene plastic, etc.

Nitrocellulose membrane (NC membrane) as the reaction site of chromatography, is one of the main raw materials of immunochromatographic test paper, need to have the following characteristics.

1Strong and stable adsorption capacity.

2Good chromatographic kinetic properties.

3Not easy to break and wrinkle.

4High sensitivity.

5Clean background after chromatography, clear detection line.

Absorbent material The main role is to maintain the capillary force of the sample. It generally consists of absorbent paper to ensure that the sample passes through the reaction zone of the membrane and is absorbed by the sample pad to prevent backflow.

Easysweet has more than 18 years of experience in this field and has strong technical strength in the optimization of colloidal gold product formulations.

The pregnancy test series products have high sensitivity, high specificity and good stability.

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