dextran

Dextran is a family of polysaccharides composed of D-glucose units linked primarily by α-1,6-glycosidic bonds, with occasional α-1,3 branches. It is produced by certain lactic acid bacteria during the fermentation of sucrose, most notably Leuconostoc mesenteroides, and occurs as a variable polymer with a broad molecular weight range. The exact branching and molecular weight depend on the microbial strain and fermentation conditions.

In industry and research, dextran refers to polymers with molecular weight (MW) from about 10 kDa to several million Da. Its solutions are highly viscous and can form gels; dextran chains can be crosslinked to produce Sephadex, a classic gel used for size-exclusion chromatography. Dextran is also used in medicine as a plasma volume expander (for example, Dextran 40, Dextran 70) and as a thickener, stabilizer, or binder in foods, cosmetics, and laboratory reagents.

It is not digested by human enzymes but can be metabolized by certain gut microorganisms with dextranases.

Safety and considerations: Dextran can interfere with coagulation tests and platelet function, and high doses may cause volume overloading or hypersensitivity reactions. Its use in medicine is controlled and monitored, and different grades are selected for specific applications.