Biotin is a stable small molecule known for its high-affinity, non-covalent interaction with Streptavidin / Avidin. The strength and specificity of this bond underpins the versatile roles of biotin-conjugated secondary antibodies in a variety of immunoassays and protein enrichment protocols; including: Immunohistochemistry (IHC), Immunofluorescence (IF), Immunocytochemistry (ICC), Enzyme-Linked Immunosorbent Assays (ELISA), Western Blotting (WB), Flow Cytometry, Affinity Purification and Immunoprecipitation. The multivalent properties of streptavidin confer high sensitivity to biotin conjugation systems enabling them to robustly detect low abundance targets. Signal amplification is achieved through the presence of multiple (>4) biotin molecules on each antibody, which is compounded by the tetravalent binding mode of streptavidin molecules. In the context of affinity purification and immunoprecipitation experiments, this facilitates efficient and specific target isolation by affording high stringency wash conditions. Target visualisation using biotin-streptavidin systems requires streptavidin conjugation to fluorescent dyes or reporter enzymes such as HRP or AP. For the latter, additional signal amplification is achieved through catalysed conversion of chromogenic, fluorescent or chemiluminescent substrates. Explore our portfolio of full length and fragmented biotin-conjugated secondary antibodies below, that are raised against a variety of primary antibody host species and their isotypes. Many of our biotinylated secondary antibodies are also available cross-adsorbed - to limit cross-species reactivity and are highly specific as a result. Note: The use of biotin-conjugates in target visualisation involves complex protocols incurring higher costs. While this may be necessary to detect very low abundance proteins, researchers should consider whether sufficiently robust signal could be achieved using HRP labeled secondary antibodies, AP labeled secondary antibodies or secondary antibodies conjugated to fluorescent dyes.