What is a loading dye used for in electrophoresis?

A loading dye is primarily used in electrophoresis to track the movement and progress of DNA or proteins as they are separated in a gel matrix. When samples are loaded into the wells of the gel, the loading dye provides a colored visual marker that enables researchers to monitor how far the samples have migrated and confirm that the separation process is proceeding effectively. This is especially important for determining when to stop the electrophoresis run, as the dye allows for real-time visualization of the separation process.

The dye typically contains one or more colored components that do not interact with the target biomolecules, ensuring that they do not affect the results of the analysis. Thus, it serves as an important tool for ensuring that samples are adequately separated and assists in visualizing and estimating the size of the biomolecules based on their migration distance compared to the loading dye.