iFluor® 647–dextran conjugate (average molecular weight ~70,000 Da) is a high molecular weight, water-soluble fluorescent probe designed for advanced studies of extracellular transport and vascular dynamics. The 70 kDa dextran polymer is covalently labeled with iFluor® 647, a far-red-emitting fluorophore with excitation and emission maxima at approximately 656 nm and 670 nm. The increased hydrodynamic size of the 70 kDa dextran significantly limits cellular internalization, allowing for prolonged extracellular residence and reduced endocytic uptake. These properties make the conjugate particularly suitable for quantitative analysis of vascular permeability, paracellular transport, and interstitial diffusion in both in vitro and in vivo models.

iFluor® 647 offers a high fluorescence quantum yield and superior photostability, providing a consistent, low-background signal in complex biological environments. Its spectral profile is closely aligned with that of Alexa Fluor® 647 and Cy5, enabling compatibility with 633 nm and 640 nm laser excitation on standard flow cytometry and fluorescence imaging platforms. Supplied as a lyophilized powder, the conjugate is readily reconstituted in aqueous buffers for immediate use in fluorescence-based assays requiring high molecular weight, extracellular fluorescent tracers.