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What does IVD core raw material contain and how should it be preserved?

As an important support for the modern medical system, the quality of IVD reagent raw materials is directly related to the accuracy of diagnosis. There are many types of IVD core raw materials, and the preservation methods vary depending on the characteristics of the raw materials. Its research and development, preparation and preservation process involves many complex links and professional technologies. Only by strictly controlling each link can the quality of IVD core raw materials be ensured and a solid guarantee for the accurate diagnosis of IVD reagents be provided.

1. Composition of IVD core raw materials
(I) Biologically active raw materials
1. Antigen: Antigens are key raw materials in IVD reagents, including proteins, polysaccharides, peptides, lipids, small molecule compounds, etc. From the source, they can be divided into natural antigens and artificial antigens. Natural antigens are directly obtained from biological tissues or cells, while artificial antigens are prepared by genetic engineering, chemical synthesis and other methods. In infectious disease diagnostic reagents, natural antigens extracted from pathogens may be used to detect whether the human body is infected with the corresponding pathogens; in some tumor marker detection reagents, artificially synthesized polypeptide antigens or recombinant antigens prepared by genetic engineering are widely used for accurate detection of tumor-related markers.
2. Antibodies: Antibodies mainly include monoclonal antibodies and polyclonal antibodies. Monoclonal antibodies are highly specific and are obtained by fusion of B lymphocytes treated with specific antigens with myeloma cells to obtain hybridoma cells, which are then screened and cultured. Polyclonal antibodies are obtained by injecting antigens into animals for immunization, extracting and purifying them from animal blood. In tumor diagnosis, monoclonal antibodies can accurately identify specific antigens on the surface of tumor cells; in infectious disease screening, polyclonal antibodies can improve the sensitivity of detection because they can recognize multiple antigen epitopes.
3. Enzymes: In in vitro diagnostic reagent raw materials, enzymes are collectively referred to as tool enzymes, such as reverse transcriptase, DNA polymerase, alkaline phosphatase, etc. These enzymes play an important role in molecular diagnostic reagents, immunodiagnostic reagents and biochemical diagnostic reagents. In fluorescent quantitative PCR detection, DNA polymerase is used to amplify target DNA fragments to achieve quantitative detection of pathogen nucleic acids; alkaline phosphatase is often used as a marker enzyme to indicate the test results by catalyzing the color development of substrates in immunodiagnosis.
(II) Other raw materials
Other raw materials include signal systems, reaction system carriers and various biologically active and fine chemical raw materials. Colloidal gold, enzyme substrate system, luminescent substances, etc. constitute the signal system, which helps to interpret the results by generating visible signals during the detection process. In the immunochromatographic test paper, after the colloidal gold-labeled antibody binds to the antigen, it aggregates and develops color on the detection line, and the detection results are presented intuitively. NC membrane, ELISA plate, magnetic beads, etc. are used as reaction system carriers to provide a place for diagnostic reactions. During the nucleic acid extraction process, magnetic beads can achieve nucleic acid separation and purification by specifically adsorbing nucleic acids. Various bioactive materials and fine chemical raw materials play a role in improving the performance of raw materials and ensuring the stability of diagnostic reactions.

2. Preparation of bioactive raw materials
(I) Raw material pretreatment
Tissues and cells can be broken by mechanical methods such as high-speed homogenization, liquid nitrogen grinding, and ultrasound, or by non-mechanical methods such as hypotonicity, repeated freezing and thawing, enzyme digestion, or surfactant treatment. However, the crushing strength must be strictly controlled to avoid denaturation of bioactive raw materials. The turbid raw materials after crushing can be preliminarily treated by methods such as high-speed centrifugation, membrane filtration, or saturated ammonium sulfate precipitation.
(II) Preliminary Purification Stage
Mainly use precipitation and centrifugal filtration methods, such as ammonium sulfate precipitation, euglobulin precipitation, isoelectric precipitation and other non-denaturing precipitation methods, or use organic solvents, acid-base, heat and other denaturing precipitation methods to remove most impurities and initially improve the purity of raw materials.
(III) Purification Stage
Based on the properties of molecular size, shape, surface charge distribution, hydrophilicity and hydrophobicity, and specific binding, use ion exchange chromatography, molecular sieve exchange chromatography, affinity chromatography, hydrophobic chromatography and electrophoresis to separate, further improve the purity of raw materials, and obtain high-purity and high-activity biologically active raw materials.

III. Preservation of biologically active raw materials
The state of biologically active raw material solutions is affected by many factors, such as pH, ionic strength, contamination or residual proteases, storage temperature and repeated freezing and thawing times. To maintain its stability, a variety of measures can be taken:
(1) Add a buffer system to adjust and stabilize the pH value to ensure that the raw materials are stored in a suitable acid-base environment; low temperature storage can reduce the activity of the raw material molecules and slow down their degradation rate;
(2) Add surfactants to prevent raw material aggregation;
(3) Use protease inhibitors to inhibit the activity of residual proteases to prevent raw materials from being degraded;
(4) Use reducing agents to maintain the reduced state of certain groups in the raw materials to maintain their activity.
(5) Freeze-drying technology is a commonly used preservation method. After freezing the raw material solution, sublimation under vacuum conditions removes water, so that the raw material is preserved in a dry solid form, greatly extending its shelf life.

Hunan Yunbang Biotech Inc. as a manufacturer of IVD reagent raw materials, supplies enzyme preparations, biological buffers, colorimetric substrates, and luminescent reagents. The types are complete and can meet a variety of experiments, with small batch differences and stable performance. If you are interested, please contact us!