How can I reduce background bands in my Western blot?
Optimize the concentration of primary and secondary antibodies. In some cases, increasing the concentration of blocking agent (BSA or non-fat dry milk) or usiing an alternative blocking solution such as Starting Block or SuperBlock may reduce background signal. After incubation with the primary antibody, wash at least 2 times with TBST (include 0.5 M NaCl in one or more of the wash steps). Avoid Nonidet P40 or Triton X-100 in buffers because protein detection is decreased when these detergents are used.
Find additional tips, troubleshooting help, and resources within our Protein Electrophoresis and Western Blotting Support Center.
I would like to dilute an HRP-conjugated primary antibody in Blocker BSA (10X) in PBS (Cat. No. 37525). How can I ensure that the BSA does not contain sodium azide?
Our liquid blocker formulations, including Blocker BSA (10X) in PBS, are free of sodium azide and mercury compounds, such as thimerosal. They only contain Kathon CG/ICP at 600 ppm, as stabilizer. Using this BSA with HRP-coupled antibodies is absolutely common.
Find additional tips, troubleshooting help, and resources within our Antibodies and Immunoassays Support Center.
Is the Blocker BSA (10X) in PBS (Cat. No. 37525) suitable for cell culture usage?
This has not been tested. Instead, we would recommend using AlbuMAX I Lipid-Rich BSA (Cat. No. 11020021 or 11020039).
Find additional tips, troubleshooting help, and resources within our Protein Electrophoresis and Western Blotting Support Center.
I used a neuron-specific antibody to label my neurons. How can I reduce non-specific antibody binding?
A blocking step should be performed to reduce fluorescence due to non-specific antibody binding. A common blocking step is the addition of a 2-5% solution of bovine serum albumin (fraction V defatted BSA). Another approach employs the addition of a 5-10% solution of serum from the species in which the secondary antibodies were raised. For example, when using goat anti-mouse IgG secondary antibodies, samples may be effectively blocked with 5-10% normal goat serum. To further reduce background fluorescence, the Image-iT FX Signal Enhancer can be included as a pre-blocking step to decrease non-specific labeling due to charge interactions between the dyes on the conjugates and the cellular constituents.
If you are using a secondary antibody make sure that the species of the antibody is not the same as the species of the sample. For example do not use an anti-mouse secondary antibody on mouse tissue.
Titrate the antibody to the lowest concentration you can use and still get adequate signal.
Try using a fluorescently tagged primary antibody because it should give reduced background but be aware this can reduce signal intensity.
Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.
After labeling with my antibody, I am seeing non-specific background binding in my cells or tissue. What could be the cause?
There can be many causes, including insufficient blocking, too high a concentration of the primary or secondary antibody, or degraded primary or secondary antibody. A “no-primary antibody” control can help determine if the secondary antibody is at fault. Otherwise, we recommend trying more stringent blocking or lower concentrations of primary and secondary antibodies.
Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.
