Human sorbitol dehydrogenase (SDH) ELISA kit

Instructions for use of human sorbitol dehydrogenase (SDH) ELISA kit

Human sorbitol dehydrogenase (SDH) ELISA kit is for in vitro research use only, not for clinical diagnosis!

Detection range: 0.312 U / L-20 U / L, please use the following concentration values ​​for drawing standard curve: 20 U / L, 10 U / L, 5 U / L, 2.5 U / L, 1.25 U / L, 0.625 U / L, 0.312 U / L.

Minimum detection limit: 0.2 U / L

Intended application: ELISA method for quantitative determination of SDH content in human serum, plasma or other related biological fluids.

Experimental principle: The microSD plate is coated with purified SDH antibody to make a solid-phase carrier. Samples or standards, biotinylated SDH antibody, and HRP-labeled avidin are added to the microwell in sequence, and washed thoroughly Substrate (TMB) color development. TMB is converted into blue under the catalysis of peroxidase, and into the final yellow under the action of acid. The color depth is positively correlated with the SDH in the sample. The absorbance (OD value) was measured with a microplate reader at a wavelength of 450 nm, and the sample concentration was calculated.

Composition and preparation of sorbitol dehydrogenase (SDH) ELISA kit:

1. Microplate: one piece (96 wells)

2. Standard product (lyophilized product): 2 bottles, please prepare within 15 minutes before use. Each bottle is diluted to 1ml with sample diluent. After capping, it is allowed to stand at room temperature for about 10 minutes. At the same time, it is inverted / rubbed repeatedly to help dissolution. Its concentration is 40 U / L. After diluting it to 20 U / L, do it again Series ratio dilution (Note: Do not directly perform ratio dilution in the plate), respectively formulated into 20 U / L, 10 U / L, 5 U / L, 2.5 U / L, 1.25 U / L, 0.625 U / L , 0.312 U / L, the sample dilution is directly used as a blank well 0 U / L. To prepare a 10 U / L standard: take 0.5 ml (not less than 0.5 ml) of the above 20 U / L standard and add it to an Eppendorf tube containing 0.5 ml of sample diluent, mix well, and so on for the remaining concentrations.

3. Sample diluent: 1 × 20ml.

4. Test dilution A: 1 × 10ml.

5. Test diluent B: 1 × 10ml.

6. Detection solution A: 1 × 120 per bottle (1: 100). Before use, dilute with Test Diluent A 1: 100 (for example: 10 Test Solution A / 990 Test Diluent A), mix well, and prepare according to the pre-calculated total amount required for each experiment (100 / Hole), more 0.1-0.2ml should be prepared during actual preparation.

7. Detection solution B: 1 × 120 per bottle (1: 100). Dilute 1: 100 with test dilution B immediately before use. The dilution method is the same as that of Test Solution A.

8. Substrate solution: 1 × 10ml / bottle.

9. Concentrated washing liquid: 1 × 30ml / bottle, each bottle is diluted 25 times with distilled water.

10. Stop solution: 1 × 10ml / bottle (2 mol / L H2SO4).

11. Lamination: 5 sheets

12. Instruction manual: 1 copy

Bring your own items:

1. Distilled or deionized water, filter paper

2. Microplate reader (It is recommended to preheat the instrument before use)

3. Micro dosing device and pipette tip, EP tube

Collection and preservation of specimens:

1. Serum: Whole blood samples should be left at room temperature for 2 hours or 4 overnight. After centrifugation at 1000 g for 20 minutes, take the supernatant for detection, or store the supernatant at -20 or -80, but avoid repeated freezing and thawing. .

2. Plasma: EDTA or heparin can be used as an anticoagulant. Centrifuge the sample at 1000 g for 15 minutes within 30 minutes after collection. The supernatant can be taken for detection, or the supernatant should be stored at -20 or -80, but avoid repeated Freeze and thaw.

3. Other biological specimens: centrifuge at 1000 g for 20 minutes, take the supernatant for testing, or store the supernatant at -20 or -80, but avoid repeated freezing and thawing.

Note: The above specimens should be sealed and stored, 4 should be stored for less than 1 week, -20 should not exceed 1 month, -80 should not exceed 2 months; specimen hemolysis will affect the final test results, so hemolysis specimens should not be tested .

Steps:

Before starting the experiment, all reagents should be equilibrated to room temperature, and the reagents should not be dissolved directly at 37; when preparing reagents or samples, they must be thoroughly mixed, and try to avoid foaming when mixing. The sample content should be predicted before the experiment. If the sample concentration is too high, the sample should be diluted to make the diluted sample meet the detection range of the kit, and then multiplied by the corresponding dilution factor when calculating.

1. Add sample: set blank hole, standard hole and sample hole to be tested respectively. Add 100% of the sample diluent to the blank well, and 100% of the standard or the sample to be tested in the remaining well. Be careful not to have air bubbles. Add the sample to the bottom of the enzyme plate when adding the sample. Try not to touch the wall of the well. Cover or cover the target plate and incubate at 37 for 2 hours. To ensure that the experimental results are valid

For each experiment, please use a new standard solution.

2. Discard the liquid and dry it without washing. Add 100 working solutions of detection solution A (prepared before use) to each well, add the microplate to the membrane, and incubate at 37 for 1 hour.

3. Discard the liquid in the hole, spin dry, wash the plate 3 times, soak for 1-2 minutes each time, about 400 per hole, spin dry (you can also pat dry the liquid in the hole).

4. Add 100% of the working solution of the test solution B (prepared before use) to each well, add a coating, and incubate at 37 for 1 hour.

5. Discard the liquid in the hole, spin dry, wash the plate 5 times, the method is the same as step 3.

6. Add substrate solution 90 per well, enzyme label plate and film 37 to avoid light and color development (reaction time is controlled at 15-30 minutes, when the first 3-4 wells of the standard well have a clear blue gradient, the last 3 -When the gradient of 4 wells is not obvious, it can be terminated).

7. Add 50% stop solution to each well to stop the reaction. At this time, the blue color turns to yellow. The order of adding the stop solution should be the same as that of the substrate solution.

8. Immediately measure the optical density (OD value) of each well with a microplate reader at a wavelength of 450 nm.

Note:

1. Preparation of reagents: All reagents should be equilibrated to room temperature before use. Please save the reagents according to the instructions immediately after use. Please use disposable tips during the experiment to avoid cross contamination.

2. Sample addition: when adding samples or adding reagents, if the time interval between the first well and the last well is too large, it will result in different "pre-incubation" time, which will obviously affect the measured value Accuracy and repeatability. The time of one sample addition (including standard and all samples) is best controlled within 10 minutes. It is recommended to set up multiple holes for experiments.

3. Incubation: In order to prevent the sample from evaporating, place the enzyme-labeled plate with a cover or membrane in the wet box during the experiment to avoid liquid evaporation; the next step should be performed as soon as possible after washing the plate, and should be avoided at any time The microplate is in a dry state; at the same time, the given incubation time and temperature should be strictly observed.

4. Washing: The washing liquid remaining in the reaction well during the washing process should be patted dry on the filter paper. Do not put the filter paper directly into the reaction well to absorb water. At the same time, the remaining liquid and fingerprints on the bottom of the plate should be eliminated to avoid affecting the final enzyme label. Instrument reading.

5. Preparation of reagents: before using, please shake the hands a few times or centrifuge for a while to prevent the liquid on the tube wall or bottle cap from depositing to the bottom of the tube. Standard products, working solution A, and working solution B should be prepared according to the required amount, and prepared with the corresponding diluent, not to be confused. Please accurately prepare the standard and working solution, and try not to prepare in small amounts (such as when drawing the test solution A, it should not be less than 10 at a time) to avoid concentration errors due to inaccurate dilution; do not reuse the diluted standard and test Solution A working fluid, detection solution B working fluid.

6. Control of reaction time: Please observe the color change of the reaction well regularly after adding the substrate (for example, every 10 minutes). If the color is dark, please add the stop solution in advance to stop the reaction to avoid the reaction being too strong and affecting the microplate reader. Optical density reading.

7. Substrate: Please keep the substrate away from light, and avoid direct exposure to strong light during storage and incubation.

Washing method:

1. Automatic plate washing: If there is an automatic plate washing machine, it should be used in the formal experiment process after being used proficiently.

2. Manual plate washing method: Inject at least 0.4ml of the recommended washing buffer into the well, soak for 1-2 minutes, aspirate (do not touch the plate wall) or shake off the liquid in the enzyme plate, and put a few layers on the experimental table Absorbent paper, with the microtiter plate down and vigorously pat several times; repeat this process several times as needed.

Specificity: This kit can detect recombinant or natural human SDH at the same time, and does not cross-react with other related proteins.

Calculation: The OD value of each standard and sample is deducted after deducting the OD value of the blank hole (seven-point diagram). If multiple holes are set, the average value should be used for calculation. Taking the concentration of the standard product as the ordinate (logarithmic coordinate) and the OD value as the abscissa (logarithmic coordinate), a standard curve is drawn on the logarithmic coordinate paper. It is recommended to use professional curve making software for analysis, such as curve expert 1.3, according to the OD value of the sample, find the corresponding concentration from the standard curve and multiply it by the dilution factor; or use the concentration and OD value of the standard to calculate the regression equation of the standard curve, Substitute the OD value of the sample into the equation, calculate the sample concentration, and then multiply it by the dilution factor to obtain the actual concentration of the sample.

Explanation:

1. Avoid exposing the reagent to strong light during storage and incubation. All reagent bottle caps must be tightly closed to prevent evaporation and contamination. Reagents should be protected from microbial contamination, because the interference of proteolytic enzymes will lead to erroneous results.

2. Aspirate the reagents carefully and strictly observe the given incubation time and temperature. Please note that when drawing samples / standards, enzyme conjugates or substrates, if the time interval between the first well and the last well is too large, it will result in different "pre-incubation" time, which obviously Affect the accuracy and repeatability of the measured value. Moreover, insufficient washing will affect the test results.

3. Storage of the kit: some reagents are stored at -20 ° C, and some reagents are stored at 2-8 ° C, depending on the label.

4. Salt will precipitate out in the concentrated washing liquid, and it can be heated and dissolved in the water bath when diluted.

5. There may be some water-like substances in the well of the enzyme-linked plate just opened. This is a normal phenomenon and will not have any impact on the experimental results.

6. There may be inconsistencies between the Chinese and English instructions. Please refer to the English instructions.

7. All samples should be managed, and the samples and testing devices should be processed according to the prescribed procedures.

8. Validity: 6 months