Methylene Blue

Dyes and stains can serve more than just decorative purposes. Scientists use them to color cell and tissue samples for examination under a microscope.

Methylene blue was originally developed as a cotton textile dye in 1876, but it quickly found its way into biomedical labs. This blue stain helped researchers see structures like the nucleus inside the cell more clearly. Interestingly, clinicians also realized the dye had antimalarial qualities and could be used as a drug.

Methylene blue is positively charged. It is attracted to negatively
charged molecules, like DNA and RNA, making them visible under a microscope.

Shutterstock/Luana Kziozek