The straight chain consists of α1->6 glycosidic linkages between glucose molecules, while branches begin from α1->4 linkages (and in some cases, α1->2 and α1->3 linkages as well). (For information on the numbering of carbon atoms in glucose, see the glucose article.) Dextran is synthesized from sucrose by certain lactic-acid bacteria, the best-known being Leuconostoc mesenteroides and Streptococcus mutans. Dental plaque is rich in dextrans. Dextran is also formed by the lactic acid bacterium Lactobacillus brevis to create the crystals of tibicos, or water kefir fermented beverage which supposedly has some health benefits.
Outside from these features, larger dextrans, which do not pass out of the vessels, are potent osmotic agents, and thus have been used urgently to treat hypovolemia. The hemodilution caused by volume expansion with dextran use improves blood flow, thus further improving patency of microanastomoses and reducing thrombosis. Still, no difference has been detected in antithrombotic effectiveness in comparison of intraarterial and intravenous administration of dextran.
Dextrans are available in multiple molecular weights ranging from 10,000 Da to 150,000 Da. The larger dextrans are excreted poorly from the kidney and therefore remain in the blood for as long as weeks until they are metabolized. Subsequently, they have prolonged antithrombotic and colloidal effects. In this family, dextran-40 (MW: 40,000 Da), has been the most popular member for anticoagulation therapy. Close to 70% of dextran-40 is excreted in urine within the first 24 hours after intravenous infusion while the remaining 30% will be retained for several more days.
It is also used in some size-exclusion chromatography matrices; an example is Sephadex.
Dextran has also been used in bead form to aid in bioreactor applications.
Dextran has been used in immobilization in Biosensors.
Dextran preferentially binds to early endosomes; fluorescently-labelled dextran can be used to visualize these endosomes under a fluorescent microscope.
Dextran can be used as a stabilising coating to protect metal nanoparticles from oxidation and improve biocompatibility.
Partitioning of charged and neutral dextran-dye derivatives in biphasic cellulose nanocrystal suspensions (1).(Report)
Jun 01, 2008; Abstract: The partitioning behaviour of dye-labeled Dextrans of high molecular weight in aqueous suspensions of native...