生物素，固定在葡聚糖上

Biotin/vitamin B₇/vitamin H is a water-soluble B complex vitamin. It consists of an uredo ring fused by a tetrahydrothiophene ring. Biotin is readily available in several foods, like whole grains, nuts, legumes, unpolished rice and egg yolk. The normal gut flora also produces this vitamin.

Biotin, immobilized on dextran has been used in in vivo labeling of the lectin structures of vascular endothelium to demonstrate the functionality of CD31⁺ vessels.

Dextrans are used in many applications as volume extenders, stabilizers, matrix components, binding platforms, lubricants and physical structure components. Biotinylated dextran may be used to capture or detect avidin/strepavidin conjugated molecules.

Biotin acts as an important cofactor for carboxylase enzymes in various metabolic pathways. It is implicated in keratin synthesis and hence is used as a supplement for skin, hair and nail growth. Biotin functions as a coenzyme in the metabolism of fats, fatty acids and amino acids such as isoleucine and valine. It is involved in gluconeogenesis and citric acid cycle. Biotin is essential for cell growth.It assists the transfer of carbon dioxide and also maintains a steady blood sugar level.