99% Dextran 9004-54-0

What is Dextran? How does it work?

Dextran is a highmolecularweight microbial polysaccharide built from glucose units (CAS No. 9004540). It appears as a white to offwhite powder or granules and dissolves readily in water to form a clear, viscous aqueous solution. Its molecular backbone consists of glucose units connected by α1,6 glycosidic bonds, while sidechain branches are formed mainly via α1,3 glycosidic bonds. Its molecular weight ranges from 3 kDa to 2000 kDa. Longer molecular chains and a higher degree of branching produce greater solution viscosity. Thanks to the strong hydrophilicity of abundant hydroxyl groups, the thickening effect of long polymer chains, the resistance to digestion of α1,6 glycosidic bonds, the ability to form crosslinked gel networks, as well as favourable biocompatibility and biodegradability, dextran finds broad applications in food, laboratory research, biotechnology, nanomaterials, cosmetics and agriculture. In the food industry, it serves as a thickener and stabilizer,  humectant , anticrystallization agent and dietaryfiber ingredient in candy, baked goods, ice cream and similar products. It is used in laboratories as Sephadex gelfiltration chromatography media and biochemical research reagents. In biotechnology, it acts as a bioreactor carrier; in nanotechnology, it functions as a stabilizing coating for nanoparticles; in cosmetics, it is a moisturizing and filmforming agent; and in agriculture, it is employed as a waterretention material.

Basic Information

Chinese name: Dextran; English name: Dextran; CAS No.: 9004540; Molecular formula: H(C₆H₁₀O₅)ₓOH (x varies with molecular weight); Molecular weight: approximately 3–2000 kDa (gradedependent); No fixed melting point, decomposes when heated above roughly 200 °C; Synonyms: Dextran, αglucan, microbial glucan, etc.

Structurally, dextran uses alphaDglucopyranose as its repeating basic unit. The glucose units along the main chain are linked by α1,6 glycosidic bonds to create a linear backbone. A small proportion of mainchain glucose residues form side branches through α1,3 glycosidic bonds (minor amounts of α1,4 and α1,2 glycosidic bonds also exist), yielding a branched polymer architecture. Each glucose unit carries three hydroxyl groups. Longer polymer chains and increased branching raise viscosity. Dextran grades with different molecular weights show a continuous transition from shortchain, lowviscosity types to longchain, highviscosity types. After crosslinking, dextran forms a threedimensional porous gel network.

Physical properties

Dextran is a white to paleyellow powder or granular solid. It dissolves easily in water but is insoluble in organic solvents such as ethanol and diethyl ether. Its aqueous solution is transparent to translucent and viscous; viscosity increases with molecular weight and concentration. It has no definite melting point and slowly decomposes and carbonizes upon heating. It is optically active, and its aqueous solution is dextrorotatory. It can be formulated into powder, liquid solution, microbeads and hydrogel forms.

Chemical properties

Dextran is a neutral polysaccharide containing numerous hydroxyl groups, which confer high hydrophilicity. It forms hydrogen bonds, absorbs and retains water, and dissolves in water to produce viscous liquids. Its hydroxyl groups can undergo etherification, esterification and crosslinking reactions to yield derivatives including crosslinked dextran gel, carboxymethyl dextran and fluorescently labelled dextran. The α1,6 glycosidic bonds are not readily hydrolysed by human digestive enzymes, giving dextran digestiveresistance properties. The polymer backbone exhibits mild and stable chemical behaviour. It can be degraded by microorganisms and possesses good biocompatibility and biodegradability.

Mechanisms of action

Why can dextran perform diverse functions in food, research, biotechnology, dailycare and agricultural fields? Its main working mechanisms are listed below.

1. Hydrophilic effect of polyhydroxyl groups

Each glucose unit of dextran contains three hydroxyl groups. A large quantity of hydroxyl groups forms hydrogen bonds with water molecules, delivering excellent water solubility, water absorption and moisturizing performance. This property underpins its use as a thickening stabilizer,  humectant  and waterretention material.

2. Thickening and networkforming mechanism of long polymer chains

Long dextran molecular chains entangle with one another in aqueous systems and occupy hydrodynamic volume, markedly increasing solution viscosity and constructing spatial networks. This creates thick, stable textures in food matrices and forms the basis for its application as a food thickener and stabilizer.

3. Antidigestive and dietaryfiber mechanism

Human digestive enzymes hydrolyse α1,6 glycosidic bonds only slowly. Dextran resists digestion, reaches the intestinal tract, acts as dietary fibre and can be fermented by intestinal microbiota. This characteristic enables its application as a dietaryfiber source and potential prebiotic.

4. Sieving mechanism of crosslinked gel

Crosslinked dextran forms a gel with a tunable threedimensional pore network. Molecules of different sizes travel through the pores at different rates, achieving separation according to molecular dimensions. This principle is the foundation of its use as gelfiltration chromatography media.

5. Surfaceadsorption stabilization mechanism

Dextran molecules adsorb onto the surfaces of particles, microcarriers and nanoparticles and build a hydrophilic sterichindrance layer. This prevents particle aggregation, oxidation and sedimentation, supporting its use as a stabilizing coating for nanomaterials and a suspension stabilizer.

6. Biocompatible filmforming mechanism

As a natural, biocompatible and biodegradable polysaccharide, dextran solution forms a transparent, flexible film after drying. The film adheres to biological and material surfaces and provides protection and moisturization, making dextran useful as a filmforming agent and protective coating in cosmetics.

Applications of Dextran

1. Food thickeners and stabilizers (food industry)

Related products: candy thickeners, jam stabilizers, jelly gelling agents, icecream stabilizers, yoghurt stabilizers, dairybeverage thickeners, fruitjuicebeverage stabilizers, bakeryfilling stabilizers, sauce thickeners, etc.

Working principle: Long dextran chains intertwine in water and build viscous networks that raise the viscosity and consistency of food systems. Pulp particles, milk fat and fine solids are evenly dispersed without sedimentation or phase separation, stabilizing the texture of jams, yoghurts, beverages and ice cream. It is a polysaccharide food additive combining thickening and stabilizing functions.

2. Food humectant and anticrystallization agents (food industry)

Related products: humectants for pastries and bread, anticrystallization agents for sugar coatings, syrup stabilizers, anticrystallization additives for frozen desserts, humectants for soft candies, antidrying agents for preserved fruits, shelflife improvers for baked goods, etc.

Working principle: The abundant hydroxyl groups of dextran provide strong waterholding capacity. It traps moisture inside food, slows starch ageing and product hardening, and extends the soft shelf life of bread and pastries. Meanwhile, dextran molecules disrupt the ordered packing of sugar molecules, suppressing sugar crystallization and graining in coatings and syrups and limiting icecrystal growth in frozen desserts. It is widely used to improve waterholding capacity and textural stability in food formulations.

3. Dietary fibre and prebiotics (functionalfood industry)

Related products: dietaryfiber powder, prebiotic solid beverages, fiber ingredients for functional drinks, fiber additives for cereal bars, fiber components of mealreplacement powders, fiber fortifiers for enriched foods, guthealth food ingredients, etc.

Working principle: Human digestive enzymes hydrolyse the α1,6 glycosidic bonds of dextran slowly. Dextran survives gastrointestinal digestion and arrives in the intestine, stimulating intestinal peristalsis and behaving like soluble dietary fibre. It can also be fermented by beneficial gut flora to produce shortchain fatty acids. Therefore, it serves as a functionalfood fibre ingredient that promotes satiety and intestinal health.

4. Laboratory gelfiltration chromatography media (research and biotechnology laboratories)

Related products: Sephadex gelfiltration media, desalting gel columns, molecularweight calibration standard dextran, gelchromatography packing materials, macromolecule separation media, purification gels, etc.

Working principle: Crosslinked dextran forms a 3D gel network with controllable pore sizes. In a gel column, larger molecules elute first while smaller molecules enter the pores and elute later. Biomacromolecules can thereby be separated, purified and desalted according to molecular weight. Standard dextran samples are used for column calibration and molecularweight measurement. It is one of the most common chromatography media in biochemical laboratories.

5. Biochemical separation and tracer reagents (research laboratories)

Related products: components of aqueous twophase extraction systems, osmoticstress reagents, fluorescently labelled dextran tracers, immobilization carriers for biosensors, microfluidic tracer reagents, etc.

Working principle: Dextran can form immiscible aqueous twophase systems together with polyethylene glycol, enabling mild separation of cells, proteins and biological particles. Its highmolecularweight osmoticpressure property allows controlled osmoticstress treatment for investigating conformational changes of biomolecules. Its polyhydroxylated surface can immobilize enzymes and biorecognition molecules, making dextran a versatile biochemical research reagent.

6. Microcarriers and bioreactor media for cell culture (biotechnology industry)

Related products: cellculture microcarriers, bioreactor microbeads, enzymeimmobilization carriers, fermentation auxiliaries, etc.

Working principle: Dextran microbeads have hydrophilic surfaces and good biocompatibility. Their surface functional groups can immobilize enzymes and cells, so they are essential consumables in biopharmaceutical and biotechnology workflows.

7. Stabilizing coatings for nanomaterials (nanomaterials industry)

Related products: metalnanoparticle stabilizers, protective coatings for gold and silver nanoparticles, stabilizing coatings for ironoxide nanoparticles, quantumdot coatings, drugnanocarrier coatings, nanosuspension stabilizers, biomedical nanoprobe coatings, etc.

Working principle: Dextran molecules adsorb onto nanoparticle surfaces and build a hydrophilic sterichindrance layer. This prevents nanoparticle aggregation and sedimentation, protects metallic nanoparticles against oxidation and corrosion, and imparts good water dispersibility and biocompatibility. Dextran is a frequently adopted stabilizer and coating material for nanomaterial preparation and functionalization.

8. Cosmetic humectant and filmforming agents (cosmetics industry)

Related products: moisturizing additives for skin creams, humectant for serums, filmforming  humectant for facial masks, smoothing agents for hair conditioners, film formers for styling products, cosmetic filmforming agents, moisturizing filmformers for suncare formulations, skinfeel improvers for facial cleansers, etc.

Working principle: Dextran carries abundant hydroxyl groups and possesses strong moisturizing capacity. It absorbs water on skin and hair surfaces and reduces transepidermal water loss, delivering a moisturized skin sensation. Its aqueous solution dries into a transparent, flexible film that adheres to skin and hair. It is a cosmetic polysaccharide raw material combining moisturizing and filmforming functions with high biocompatibility and mildness.

9. Agricultural waterretention materials (agriculture)

Related products: soil moistureretaining agents, droughtresistant seedlingprotection agents, biodegradable waterretention gels, additives for soillessculture substrates, seedcoating waterretention agents, waterretention materials for seedling transplantation, soilconditioning waterretention agents for sandy land, etc.

Working principle: Dextran is highly hydrophilic and absorbs large volumes of water to form waterretaining gels. When applied to soil, it releases water slowly for crop roots, lowering irrigation frequency and improving drought tolerance and seedling survival. Since dextran is biodegradable, it gradually decomposes into harmless substances after use without soil contamination. It represents an environmentally friendly agricultural waterretention and soilconditioning material.

III. Summary

Dextran (CAS No. 9004540) is a microbial polysaccharide with an α1,6linked glucose backbone and α1,3 glycosidic side branches. Its key characteristics originate from multiple hydroxyl groups that create hydrophilicity, long polymer chains that produce thickening, digestiveresistant glycosidic bonds, crosslinkable gelsieving behaviour, surfaceadsorption stabilization, biocompatibility and biodegradability. It is widely applied as a food thickener and stabilizer,  humectant and anticrystallization agent, dietaryfiber ingredient, laboratory Sephadex gelfiltration medium and biochemical tracer reagent, nanomaterial stabilizer, cosmetic moisturizing filmformer and agricultural waterretention material. Its polyhydroxylated architecture and α1,6 glycosidic bonds account for its thickening and moisturizing performance, molecular sieving and separation ability, and stabilization of nanoparticles and cultured cells. For these reasons, dextran finds extensive use in the food sector, scientific research, cosmetics and agriculture.