Biotinylated means ‘being combined with one or more biotin residue’. Biotinylation is the process of non-covalently bonding biotin to proteins, nucleic acids or other macromolecules.

Biotin is a naturally occurring, water-soluble B-complex vitamin. It has a strong affinity to avidin and streptavidin, two tetrameric proteins that can form large complexes by binding up to 4 biotins per molecule. The bonding of multiple biotin molecules to a secondary antibody allows for easier detection of proteins expressed at low levels. Biotinylated antibodies provide a powerful means of amplifying signals and detecting low-abundance proteins in immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), and several other areas of molecular biology and bionanotechnology.