Fluorescent labels (also known as fluorescent labels or fluorescent probes) are chemically linked molecules that help detect biomolecules such as proteins antibodies or amino acids. In general, fluorescent labeling, uses a fluorescent group of reactive derivatives called fluorescent molecules. Fluorescent groups selectively bind to specific regions or functional groups on the target molecule and can be linked chemically or biologically. Various labeling techniques, such as enzyme markers, protein markers and gene markers, are widely used. Ethidium bromide, fluorescein and green fluorescent protein are common labels. The connection of fluorescent dyes to proteins and other biomolecules is a common strategy for better understanding the structure and function of proteins.