ELISA (Enzyme linked immunosorbent assay) is a biological analysis technique based on the immunoreaction of antigen and antibody and the efficient catalytic reaction of enzyme. It can be used for qualitative and quantitative analysis of target protein in the sample like serum and plasma.
A complete ELISA kits which contains all the reagents that you can use in your experiments, its corresponding experimental operation can refer to the instruction manual directly. If this is the first time you know about the ELISA experiment, pre-experiment is a good choice. For the sample to be tested, you can get the preliminary judgement by pre-experiment. For example, whether the sample needs to be diluted or not.
So how to do the pre-experiment?
1. Please refer to the instruction manual for the preparation of the sample. If it is not mentioned, please contact us (Just click "chat now" in the lower right corner).
2. All the reagents used should be prepared according to the requirements of the specification. Pre-experiment generally set up 2 strips(16 wells) (fig),
Taking CSB-E04505m Mouse Brain derived neurotrophic facor, BDNF ELISA Kit as an example, the OD value of the standard as follows:
standard substance | OD | pg/ml |
---|---|---|
S7 | 2.0365 | 1000 |
S6 | 1.4281 | 500 |
S5 | 0.9769 | 250 |
S4 | 0.5931 | 125 |
S3 | 0.3641 | 62.5 |
S2 | 0.2563 | 31.2 |
S1 | 0.2279 | 15.6 |
S0 | 0.1529 | 0 |
The sample to be tested was brain tissue K1, M1 (random number). Different dilution times were selected for pre-experiment. The corresponding OD values are as follows:
Sample number | dilution multiple | OD | concentration |
---|---|---|---|
K1 | the original solution | 1.2293 | 380.80641 |
10 | 0.3141 | 418.84472 | |
100 | 0.1507 |
|
|
1000 | 0.1325 |
|
|
M1 | the original solution | 1.0488 | 291.60631 |
|
10 | 0.2661 | 303.33879 |
|
100 | 0.1446 |
|
|
1000 |
|
|
3. Using Curve Expert 1. 4 software to draw the standard curve of OD value and concentration value of the standard substance, as follows: (For details of the drawing process, please refer to: https://www.cusabio.com/m-225.html)
You can obtain the concentration of the sample to be tested by putting the OD value of the sample into the formula. (For those with a dilution multiple, you need to multiply the dilution multiple).
Choose the concentration that the sample to be tested is steepness in the curve.
In the experiment of detecting brain tissue by CSB-E04505m, the original solution can be considered.
4. The appropriate sample dilution multiple is determined by the pre-experiment, and then you can conduct the formal experiment. The specific experimental procedure should refer to the relevant instruction (Please mark in the experiment). The specific layout is as follows:
(Note: the competitive method is slightly different. You must strictly follow the specifications)