Fluorescent derivatives of dextran and other polysaccharides are primarily used for studying permeability and transport in cells and tissue. An added benefit is that fluorescence measurements can provide quantitative data on the permeability of healthy versus diseased tissues. Such studies can be performed in real time by intravital fluorescence microscopy. The technique offers high sensitivity; concentrations down to 1 μg/ml can be detected in tissue fluids.
Other application areas are studies of drug delivery and microcirculation. Fluorescent derivatives can also be used as molecular size indicators in for example research kits. Our fluorescent polysaccharides modified with carboxymethyl (CM) or diethylaminoethyl (DEAE) gives the possibility to study the effect of charge on permeability. Our lysine-derivatives provide tools for bioconjugation and fixation, which can be used for preserving cells and tissue in a-like-like sate. Read more about applications here.
Microvascular flow and glomerular filtration
Movie. Microvascular flow and glomerular filtration are seen in a living rat kidney through the use of 150 kDa TRITC-dextran (red, microvascular flow) and a 4kDa FITC-dextran (green, glomerular filtration), both from TdB Labs. The initial part of the movie shows a glomerulus in the center and cross sections of surrounding tubules (orange); the nuclei in all cells appear cyan. The large 150 kDa TRITC-dextran is slowly infused in first, exhibiting spikes in fluorescence intensity as the material distributes throughout the bloodstream. After equilibration, the small 4kDa FITC-dextran is infused in and quickly filters across the glomerular filtration barrier and then travels along the proximal tubules surrounding the glomerulus.
Antonia Red™ Products
Antonia Red™ (583 nm/602 nm) is a novel red-shifted dye developed by TdB Labs. The dye residue exhibits high photo-and chemical stability and bright fluorescence. We produce Antonia Red- dextran and Antonia Red-lysine-dextran from 4 kDa to 150 kDa.
TdB Labs supply polysaccharide derivatives labeled with ATTO488™ (502nm/524 nm) and ATTO647n™ (646 nm/664 nm). Characteristics features of ATTO dyes include strong absorption, high quantum yield and photo-stability.
FITC-derivatives have been used for a variety of biological applications for more than 40 yeras. TdB Labs produce a wide range of FITC-derivatives (490 nm/520 nm) with a mean molecular weight ranging from 4 kDa to 2000 kDa. Our portfolio includes for example derivatives of dextran, polysucrose, inulin and more.
Our TRITC-derivatives (550 nm/572 nm) includes derivatives of dextran, hyaluronic acid and polysucrose. We produce TRITC-derivatives with a molecular weight ranging from 4 kDa to 2000 kDa. TRITC is less pH-dependent compared to FITC.
Our product portfolio consist of more than 30 different product groups- 21 of them are fluorescent. We offer dextran – and other polysaccharide derivatives labelled with several different fluorophores. This include for example the well-know FITC (493 nm/518 nm) and TRITC (550 nm/572 nm), which have been used for studying permeability for more than 40 years. Our product catalogue also comprises the ATTO™-dyes ATTO488 (502 nm/524 nm) and ATTO647N (46 nm/664 nm), which are suitable for single molecule detection. We also have our propriety red-shifted Antonia Red™ (583 nm/602 nm), which shows a bright fluorescence, excellent chemical- and photostability and is non pH-dependent.
All polysaccharide derivatives from TdB Labs have a low polydispersity (PD), which means that the ratio of Mw/Mn is close to 1. This is especially important for permeability studies; a low PD of the product gives more reliable and reproducible results. Fluorescent dextran derivatives from TdB Labs has proven superior in terms of polydispersity compared to one of our competitor in the study ”Multiple factors influence glomerular albumin permeability in rats.” By RM Sandoval et al., J Am Soc Nephrol, 2012 Mar, 23(3)447-57.