Fluorescein isothiocyanate

Fluorescein Isothiocyanate (FITC) is a derivative of fluorescein, used extensively as a fluorochrome in various biological research applications. It is a reactive dye that binds to amino groups in proteins, making it useful for labeling and tracking cells and molecules.

Chemical Structure

FITC is a compound of fluorescein, with an isothiocyanate functional group replacing a hydrogen atom on the bottom ring of the structure. This modification allows it to react with amino groups in proteins, forming a stable thiourea bond.

Applications

FITC is widely used in the field of immunology, where it is used to label antibodies in a process known as immunofluorescence. This allows researchers to visualize the location of the antibodies in a cell or tissue sample, providing valuable information about the distribution and concentration of various proteins.

In addition to its use in immunofluorescence, FITC is also used in flow cytometry, a technique used to measure the physical and chemical characteristics of cells or particles in a fluid as it passes through a laser. FITC-labeled antibodies can be used to identify specific cell populations based on the presence of particular proteins.

Limitations

While FITC is a valuable tool in biological research, it does have some limitations. It is relatively sensitive to pH changes and photobleaching, which can limit its usefulness in long-term imaging studies. Additionally, its green fluorescence can sometimes overlap with autofluorescence from cells and tissues, making it difficult to distinguish the signal from the background.

See Also

• Fluorescein
• Immunofluorescence
• Flow cytometry