Dextran Conjugates

Dextran conjugates are hydrophilic polysaccharides with low toxicity that can used for tissue sections, in vivo neurons, and cultured cells. A wide range of fluorescent and biotinylated dextran conjugates are offered in several molecular weights. Most of these dextran conjugates are lysine-fixable and can be treated with formaldehyde or glutaraldehyde.

See dextran conjugates selection guide

• Properties of dextran conjugates
• Selection guide for dextran conjugates
• Dextran applications

• Endocytosis and pinocytosis
• Cell structure

Figure 1. Lineage tracing in a Xenopus laevis embryo. Lineage tracing of three dorsal blastomeres of 32-cell Xenopus laevis embryos injected with dextran conjugates. The tier 1 dorsal (A1) blastomere was injected with lysine-fixable 10,000 MW fluorescein dextran, the tier 2 dorsal (B1) blastomere with lysine-fixable 10,000 MW Texas Red dextran, and the tier 3 dorsal (C3) blastomere with lysine-fixable 10,000 MW Cascade Blue dextran. Embryos were fixed in formaldehyde, embedded and sectioned. The image on the left shows a 13 µm-thick section of a stage 6 (32-cell) embryo fixed right after injection; this section exhibits significant autofluorescence due to the presence of residual yolk. The image on the right is a stage 10 (early gastrula) embryo. Triple-exposure photographs of the sectioned embryos were taken on a Zeiss Axiophot with a 10× objective. Images contributed by Marie Vodicka, University of California, Berkeley.

Figure 2. Antero-ventral and antero-dorsal lateral line nerves in an Ambystoma mexicanum brain. The antero-ventral and antero-dorsal lateral line nerves in an Ambystoma mexicanum whole-mounted brain after labeling with 3000 MW Rhodamine Green dextran and lysine-fixable 3,000 MW tetramethylrhodamine dextran, respectively. In both cases, the dextran was applied to the respective cut cranial nerves. This photomicrograph shows the four segregated ventral fascicles of the mechanosensory lateral line fibers and the intermingling of the dorsal electrosensory fibers. Image contributed by Bernd Fritzsch, Creighton University.

Figure 3. Secondary motor neurons in a male western mosquitofish (Gambusia affinis) spinal cord. Secondary motor neurons in a spinal cord whole mount of a male western mosquitofish (Gambusia affinis affinis) that have been labeled with lysine-fixable 3,000 MW Texas Red dextran. The dextran crystals were applied to the bipinnate inclinator muscles of the anal appendicular support fin, and the dye was transported from the axons to cell body and dendrites. Motor neurons were visualized and photographed through a bandpass optical filter appropriate for Texas Red dye, by epifluorescence microscopy. Image contributed by E. Rosa-Molinar, University of Nebraska Medical Center, and Bernd Fritzsch, Creighton University.