Below is just a general guide line for a antigen-antibody-antibody dot blot assay protocol. Specific concentration need to be determined for each assay. Other type of dot blot assay, such as antibody-antigen-antibody can be performed in a similar fashion.
1. spot 1-2 microliter of antigen on to a piece of membrane, let air dry for 30 min or longer;
2. incubate with blocking buffer for 30 min -2 hr;
3. rinse with rinsing buffer, 3x5 min;
4. incubate with primary antibody, 30 min - 2 hr;
5. rinse with rinsing buffer, 3x5 min;
6. incubate with enzyme-labeled secondary antibody, 30 min - 2 hr;
7. rinse with rinsing buffer, 3x5 min;
8. add enzyme substrate, wait 5-10 min;
9. detect by eye or with colorimetric or chemiluminescent imaging system.