Dextran
In food science we use dextran for gel chromatography to separate chemicals (usually proteins). Dextran has a molecular weight 3,000 – 20,000,000. Its chemical formula is H(C6H10O5)nOH. If you know about food chemistry you can see that dextran is made up of many repeating sugar (glucose) units. It is also use as a blood thickener by doctors. They might want to do this in the case of surgery.