iFluor® 647–dextran conjugate (average molecular weight ~150,000 Da) is a high molecular weight, hydrophilic fluorescent tracer specifically engineered for extracellular labeling and macromolecular transport studies. It comprises a 150 kDa dextran backbone covalently labeled with iFluor® 647, a far-red-emitting fluorophore with excitation and emission maxima at ~656 nm and ~670 nm, respectively. The large hydrodynamic radius of the 150 kDa dextran significantly restricts cellular uptake and endocytosis, enabling selective analysis of vascular permeability, interstitial diffusion, and paracellular transport without intracellular interference.

The iFluor® 647 fluorophore exhibits high quantum yield and exceptional photostability, ensuring robust performance in both in vitro and in vivo systems. Its spectral characteristics are comparable to Alexa Fluor® 647 and Cy5, providing seamless integration into standard flow cytometry and advanced fluorescence imaging platforms equipped with 633 nm or 640 nm laser excitation. Supplied as a lyophilized powder, the conjugate is readily reconstituted in aqueous buffers, making it a versatile and reliable reagent for high-sensitivity fluorescence-based assays that require restricted cellular permeability and stable extracellular signal retention.