Biotin-PEG-NH2 is a linear heterobifunctional PEG reagent with biotins and primary amine groups at the end of the molecular chain. Streptavidin and avidin bind to linear PEG with high affinity and specificity through stable amide junctions. It can be used on the surface of biotinylated biomolecules or other materials. Biotin peg amine can be easily detected by biotin/streptavidin binding assays and is widely used for molecular target detection. Primary amines are prone to react with NHS esters, carboxylic acids, and many other functional groups. Reactions between amines and other groups allow the biotin to quickly attach to the surface of the target molecule or material. The PEG connector between the amine group and the biotin provides better water solubility, flexible bond structure, and enhanced stability.