Western blotting or Western blot is an important method in protein identification. A Western blot can detect one specific protein in a solution that contains numerous other proteins. The term Western blot specifically refers to the transfer of proteins and their detection using antibodies.

The experimental flow starts on the left side of the image. Under the letter A, the vial with many tiny molecules in three different colors is shown. The arrow points from the vial to the vertically aligned, blue rectangular membrane under the letter B. On the membrane surface, three colored molecules are separated into three groups, one group at the top of the membrane, one in the middle and one at the bottom. The thick arrow points from the blue membrane to another image of the blue rectangular with yellow, thinner rectangular behind it, also vertically aligned, under the letter C. The thin arrows pass through the blue membrane onto yellow membrane, indicating passing of colored molecules. Another arrow points to the right to the new image of the yellow rectangular membrane, under the letter D, with four structures shaped like antigens in the upper left corner of the membrane. Finally, the last arrow points toward the grey rectangular membrane, under the letter E, with one black band in the upper left corner of it.

Figure 1. Western blot experimental steps. Following sample preparation (A), the samples are loaded onto an SDS polyacrylamide gel (B) and separated by gel electrophoresis. In the next step, the separated proteins are transferred onto a membrane (C) and detected by antibodies targeting the protein of interest (D). Finally, the detected protein bands are visualized on the membrane (E).