The labelling of dextran with fluorescein via its derivative fluorescein isothiocyanate (FITC) was first described in a publication in 1973 by de Belder and Granath (ref.1). Now it is a long-established method for obtaining fluorescent-labelled polysaccharides. These products are designated as FITC-derivatives. The fluorescein moiety is bound by a thiocarbamoyl-linkage which displays good stability in-vitro and in-vivo.
TdB labs produce a wide variety of FITC-derivatives with a mean molecular weight ranging from 4 kDa to 2000 kDa. All our FITC products are supplied as a yellow to orange powder.
Maximum fluorescence is recorded in the pH range 6-8.
Excitation maximum: 490 nm.
Emission maximum: 520 nm.
Apart from dextran, we offer several other FITC labeled polysaccharides. this includes:
Our standard range of FITC products also comprises derivatives with functional groups. This includes carboxymethyl (CM)-derivatives which display a negative charge (anionic). Our diethylaminoethyl (DEAE) derivatives are positively charged (cationic). We have also developed a derivative called Q, which is a substituent of O-Trimethylammonium-glycidyl.
FITC-lysine derivatives are polysaccharides carrying the natural amino acid Lysine as a substituent.
FITC-labelled polysaccharides have been used for more than 30 years, largely for real-time studies of permeability, microcirculation, distribution and diffusion.
Derivatives with diethylaminoethyl (DEAE)-groups or carboxymethyl (CM) are often used to study the effects of charge on permeability
FITC-DEAE-polysucroses are standard FITC-polysucroses carrying cationic (positively charged) diethylaminoethyl groups. TdB Labs produce FITC-DEAE-polysucrose with the molecular weight of either70 kDa or 400 kDa.