Invitrogen™ Dextran, Alexa Fluor™ 647; 10,000 MW, Anionic, Fixable

Catalog No.	Quantity
D22914	2 mg

Catalog No. D22914 Supplier Invitrogen™ Supplier No. D22914

Description

Rigorous methods for removing as much unconjugated dye as practical, followed by assay of dextran conjugates by thin-layer chromatography to help ensure absence of low molecular weight contaminants

Labeled dextrans are hydrophilic polysaccharides most commonly used in microscopy studies to monitor cell division, track the movement of live cells, and to report the hydrodynamic properties of the cytoplasmic matrix. The labeled dextran is commonly introduced into the cells via microinjection. Dextrans are hydrophilic polysaccharides characterized by their moderate-to-high molecular weight, good water solubility, and low toxicity. They also generally exhibit low immunogeniticy. Dextrans are biologically inert due to their uncommon poly-(α-D-1,6-glucose) linkages, which render them resistant to cleavage by most endogenous cellular glycosidases.

• Succinimidyl coupling of dyes to dextran molecule, which, in most cases, results in neutral or anionic dextran
• Reaction used to produce Rhodamine Green™ and Alexa Fluor™ 488 dextrans results in final product being neutral, anionic, or cationic
• Suitable for neuronal tracing (anterograde and retrograde) in live cells
• Cell lineage tracing in live cells
• Examines intercellular communications (e.g., in gap junctions, during wound healing, and during embryonic development)
• Investigates vascular permeability and blood-brain barrier integrity
• Monitors acidification (some dextran-dye conjugates are pH-sensitive)
• Studies hydrodynamic properties of cytoplasmic matrix

• Alexa Fluor dextrans are intrinsically anionic
• To produce more highly anionic dextrans, proprietary procedure adds negatively charged groups to dextran carriers; these products are designated polyanionic dextrans
• Some applications require that dextran tracer be treated with formaldehyde or glutaraldehyde for subsequent analysis
• For these applications, lysine-fixable dextran conjugates of fluorophores or biotin
• Dextrans have covalently bound lysine residues that permit dextran tracers to be conjugated to surrounding biomolecules by aldehyde-mediated fixation for subsequent detection by immunohistochemical and ultrastructural techniques
• 10,000 MW Alexa Fluor dextran conjugates can be fixed with aldehyde-based fixatives

Cell Analysis, Cell Tracing and Tracking, Cellular Imaging, General Cell Tracing, In Vivo Imaging, Neuronal Tracing

Order Info

Shipping Condition: Room temperature

Specifications

• Product Type: Dextran
• Quantity: 2 mg
• Content And Storage: Store in freezer (-5 to -30°C) and protect from light.
• Label or Dye: Alexa Fluor Dyes
• Shipping Condition: Room Temperature
• Excitation/Emission: 650/668 nm
• Product Line: Alexa Fluor

Frequently Asked Questions (FAQs)

I can't see the structural details of neurons when I inject my fluorescent dextran. What can I do to improve the detailed structure?

If you want to see the most detailed structure you should use the low molecular weight conjugated dextrans such as the 3,000 MW dextrans.

Why isn't my fluorescently conjugated dextran signal retained after fixation?

Ensure that the dextran you are using is the fixable form (i.e., contains a primary amine). Dextrans that do not contain a primary amine will not be fixed. Another factor could be that the concentration of the dextran is too low, and the concentration use can be increased up to 10 mg/mL.

What are the charges of the dextrans?

We do not determine the net charge of the dextran conjugates. The net charge depends on the fluorophore used to label the dextran and the method of preparing the conjugate. We label some dextrans as neutral or anionic based on the fluorophore used, however the net charge of the dextran may not always be the same as the dye. The Alexa Fluor, Cascade Blue, Lucifer Yellow, fluorescein, and Oregon Green dextrans are intrinsically anionic, whereas most of the dextrans labeled with the zwitterionic Rhodamine B, tetramethylrhodamine and Texas Red dyes are essentially neutral.

What size dextran is best for neuronal tracing?

Dextrans with molecular weights from 3,000 to 70,000 have been used, however the 3,000 and 10,000 MW dextrans are most commonly used for neuronal tracing. The 3,000 MW dextrans are used for more detailed tracing of fine neuronal projections, investigating gap junctions, and diffuse more quickly; while the 10,000 MW dextrans have slower distribution, longer cellular retention, and do not cross gap junctions.

Do you have a neuronal tracing protocol?

The NeuroTrace BDA-10,000 Neuronal Tracer Kit (Cat. No. N7167) manual has a good protocol for injection procedures and neuronal tracing using the10,000 MW lysine-fixable biotin dextran amine (BDA). This protocol could potentially be applied to other fluorescent dextrans.

Please review Tables 1a and 1b on pages 4 and 5 - https://tools.thermofisher.com/content/sfs/manuals/mp07167.pdf

For Research Use Only. Not for use in diagnostic procedures.