Tetramethylrhodamine isothiocyanate
Introduction
Tetramethylrhodamine isothiocyanate (TRITC) is a red-orange fluorescent dye, commonly used in biological and medical research. It is a derivative of rhodamine, a family of synthetic dyes known for their intense fluorescence. TRITC is particularly noted for its use as a labeling agent in fluorescence microscopy and flow cytometry, where it is used to tag proteins and other biomolecules for visualization and tracking.
Chemistry
TRITC is a small organic molecule with a molecular weight of approximately 443.5 g/mol. It contains a xanthene core, which is responsible for its fluorescent properties, flanked by two methyl groups and an isothiocyanate group. The isothiocyanate group allows TRITC to react with amine groups on proteins and other biomolecules, forming a stable covalent bond. This property makes TRITC an effective labeling agent in biological research.
Fluorescence Properties
The fluorescence of TRITC is characterized by a strong absorption peak around 550 nm and an emission peak around 570 nm, resulting in a red-orange fluorescence. The fluorescence intensity of TRITC is strongly dependent on the pH of the solution, with maximum fluorescence observed at pH 8.0. TRITC also exhibits a high quantum yield, making it a highly sensitive probe for fluorescence microscopy and flow cytometry.
Applications in Biological Research
TRITC is widely used in biological research for labeling proteins, nucleic acids, and other biomolecules. The covalent bond formed between the isothiocyanate group of TRITC and the amine groups of biomolecules ensures stable labeling, even under harsh experimental conditions. This makes TRITC particularly useful in fluorescence microscopy and flow cytometry, where it allows for the visualization and tracking of labeled molecules in living cells and tissues.
Fluorescence Microscopy
In fluorescence microscopy, TRITC is used to label antibodies, which can then be used to detect specific proteins in cells and tissues. The fluorescence of TRITC allows for the visualization of these proteins under a fluorescence microscope, providing insights into their localization and function. TRITC-labeled antibodies are particularly useful in immunofluorescence studies, where they allow for the simultaneous detection of multiple proteins using antibodies labeled with different fluorescent dyes.
Flow Cytometry
In flow cytometry, TRITC is used to label antibodies or other probes that bind to specific molecules on the surface of cells. The fluorescence of TRITC allows for the detection and quantification of these molecules, providing insights into the composition and function of cell populations. TRITC-labeled probes are particularly useful in multi-color flow cytometry, where they allow for the simultaneous detection of multiple cell surface markers using probes labeled with different fluorescent dyes.
Safety and Handling
Like all fluorescent dyes, TRITC should be handled with care to prevent exposure to skin and eyes. It should be stored in a cool, dark place to prevent degradation of its fluorescent properties. TRITC is not considered particularly hazardous, but it should be handled with the same precautions as other laboratory chemicals.