Treatment methods for different types of ELISA kits
Treatment methods for different types of ELISA kits ELISA kits Generally, there are many types of samples that can be used for ELISA, such as serum, plasma, urine, cell culture supernatant or tissue homogenate. Different types of test samples are treated differently in the early stage. Proper handling of the sample is the first step in ensuring the correctness and accuracy of the ELISA assay. 1, serum Serum is one of the most commonly used samples for ELISA testing and is relatively simple to handle. Blood samples were collected in a pyrogen-free, endotoxin-free test tube or centrifuge tube, and the test tubes or centrifuge tubes were allowed to stand at room temperature for 2 hours or 4 ° C overnight to precipitate the serum. (It is best to tilt the tube or centrifuge tube to increase the cross-section of the liquid surface to allow a greater degree of serum precipitation.) Centrifuge at 1000 xg for 20 minutes at 4 ° C and carefully collect the supernatant. It is recommended to pack multiple aliquots at -20 ° C or -80 ° C to avoid repeated freezing and thawing. Hemolysis should be avoided during blood collection because red blood cells cleave release substances with peroxidase activity, and non-specific color development in HRP-labeled ELISA assays leads to inaccurate detection. Bacterial contamination should also be avoided, as the bacteria may contain endogenous HRP and cause false positives in the test. 2, plasma The ELISA kit collects blood samples from blood collection tubes or centrifuge tubes containing anticoagulants. The specimens are centrifuged at 1000 x g for 15 min at 4 ° C within 30 min after collection, and the supernatant is taken as plasma. The supernatant is packed in multiple portions and stored at -20 ° C or -80 ° C to avoid repeated freezing and thawing. Avoid using hemolyzed or hyperlipidemia specimens. Commonly used anticoagulants are EDTA, sodium heparin and sodium citrate. When testing, you should carefully read the kit instructions to check whether the kit has special requirements for anticoagulants. 3. Cell culture supernatant The cell culture supernatant was taken to a centrifuge tube, centrifuged at 1000 × g for 20 min to remove cell debris and impurities, and the supernatant was taken and stored at -20 ° C or -80 ° C to avoid repeated freezing and thawing. 4, cell lysate 1) Aspirate the medium in the plate, digest the cells with trypsin, and add the appropriate amount of medium to blow the cells off the plate. Suspended cells can be omitted. 2) The cell suspension was collected, centrifuged at 1000 x g for 10 min, the medium was discarded, and washed with pre-cooled PBS 3 times. 3) Resuspend the cells by adding an appropriate amount of pre-cooled PBS or cell lysate (by adding a protease inhibitor before use). Usually the amount of cells in one well of a 6-well plate needs to be resuspended in 150-250 μL PBS. 4) Place the sample at -20 ° C or -80 ° C, freeze the sample, and then thaw the sample at room temperature, freeze and thaw several times to allow the cells to fully lyse. The sample can also be sonicated to achieve the purpose of lysis. 5) Centrifuge at 10000 × g for 10 min at 4 ° C to remove cell debris, and take the supernatant, store at -20 ° C or -80 ° C to avoid repeated freezing and thawing. 5, tissue homogenate 1) Rinse the tissue sample with PBS (0.01 [anchor] [anchor] M, pH 7.4) to remove any residual blood or impurities from the surface of the tissue. 2) Weigh the tissue block, cut it after recording, and make the pieces as small as possible to facilitate homogenization. 3) Add the tissue to the pre-cooled PBS (add protease inhibitor before use) in a certain ratio, and place it on ice or ice bath. (Normally homogenized according to tissue weight: PBS volume = 1:9, for example, 1g of tissue sample corresponds to 9mL of PBS, the specific volume can be adjusted according to the experimental needs, the sample concentration should be multiplied by the corresponding dilution factor after the test) 4) Pipette the homogenate into the centrifuge tube, centrifuge at 5000×g for 5~10min at 4°C, take the supernatant, store at -20°C or -80°C to avoid repeated freezing and thawing. 6, other liquid biological samples such as urine, saliva Centrifuge at 1000 × g for 20 min, and take the supernatant to detect. ELISA kits In general, because the ELISA can only detect the content of soluble protein, it should be ensured that all samples are clear liquid, and the precipitate or suspended matter should be removed by centrifugation. In order to ensure the accuracy of the test, samples stored at -20 ° C or -80 ° C are best tested within 1 to 6 months; samples stored at 4 ° C should be tested within 1 week. In addition, the sample should be guaranteed to be free of NaN3, as NaN3 will inhibit the activity of HRP, leading to false negative results. Sweet corn. The light green outer leaves of sweet corn are yellow grains, but also purple and yellow. The grains are small and round, the skin is thin and soft, tender, sweet and delicious.Contains carotene, zeaxanthin, with the effect of eye protection. Sweet Corn,Corn Kernels,Sweet Corn Kernels,Fresh Corn Kernels Jilin Province Argricultural Sister-in-law Food Co., Ltd. , https://www.nongsaocorns.com
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Sweet corn is most often boiled into soups. It is a favorite soup for children and adults, whether it is made into a clear corn soup with ribs or pureed with cream.