Optimizing ELISA experiments to reduce background noise is key to ensuring data accuracy. Based on experimental experience, optimization suggestions are provided for core processes such as sealing, washing, and antibody selection

Optimization of closed conditions

Sealing is the core step in reducing non-specific binding, and the following points should be noted:

Sealing agent selection: commonly used are 5% bovine serum albumin (BSA) or skim milk powder, among which BSA is suitable for most situations, especially when the sample contains high concentrations of lipids or hemolysis, BSA should be used first to avoid interference. If detecting phosphorylated proteins, it is necessary to avoid using skim milk powder containing casein.

Sealing time and temperature: Usually sealed at room temperature for 30 minutes to 2 hours, or overnight at 4 ℃ to improve uniformity. 37 ℃ can accelerate the reaction, but it is important to avoid evaporation.

Sealing liquid preparation: It needs to be prepared and used immediately to avoid repeated freeze-thaw cycles leading to failure.

Optimization of washing steps

Adequate washing is the key to reducing background:

Washing solution selection: It is recommended to use PBS buffer containing 0.05% Tween-20 to remove unbound substances.

Washing frequency and time: It is recommended to wash 3-5 times, each time for 2-3 minutes, to ensure the removal of residual reagents.

Antibody and reagent optimization

Antibody quality: Select highly specific primary and secondary antibodies, optimize dilution factors and incubation time to avoid cross reactivity.

Development control: Reasonably adjust the concentration and time of the developing reagent to avoid excessive development leading to background elevation.

Other precautions

Protein loading capacity: Ensure the appropriate quality of loaded protein to avoid non-specific binding caused by overloading.

Experimental environment: Avoid direct exposure to strong light, especially during the color development and detection stages.