VFITC

VFITC is a fluorescent labeling reagent that belongs to the fluorescein isothiocyanate (FITC) family. It is used to tag biomolecules such as proteins, antibodies, nucleic acids, and other amine-containing molecules by forming covalent bonds with primary amines through its isothiocyanate group. As a derivative of FITC, VFITC provides green fluorescence and is commonly employed in fluorescence-based detection techniques.

Chemical and functional characteristics

VFITC dyes are designed to react with amino groups to form stable thiourea linkages. They are typically used in conjugation reactions under mildly basic conditions and are available in various reactive forms, including isothiocyanate or NHS-ester derivatives, depending on the catalog. The dye's chemistry and substitutions can influence solubility, labeling efficiency, and photophysical behavior. Like other fluorescein-based dyes, VFITC fluorescence is pH-dependent and sensitive to light, so samples are usually protected from light and stored appropriately.

Spectral properties and compatibility

VFITC shares spectral features with FITC, with excitation generally around 490–500 nm and emission near 520–530 nm, producing green fluorescence. The exact spectra can vary with the dye variant, solvent, and environment, which affects brightness and stability. VFITC is frequently used alongside other fluorophores in multi-color assays, with attention paid to spectral overlap and compensation in flow cytometry or microscopy.

Applications and handling

Common applications include immunolabeling, flow cytometry, fluorescence microscopy, and ELISA-based assays where a covalent label is required. Handling considerations include protection from light, storage at low temperatures, and careful removal of unreacted dye after conjugation. Vendors provide specific protocols for conjugation, purification, and quality assessment. Safety data sheets should be consulted for chemical handling and disposal.