Bead-based immunoassays

Wal, F.J. van der; Bergervoet, J.H.W.; Achterberg, R.P.; Haasnoot, W.


Since the first immunoassay with (radioactive) labeled antibodies in the middle of the 20th century [1], many different formats on various platforms have been developed, using antibodies for capture and/or detection. If antibodies are used to capture compounds, a support, such as the wall of a microtiter-plate well in ELISAs or nitrocellulose in a lateral flow assays, is required for passive binding of antibodies in order to create a layer of capture antibodies. When the purpose of antibodies is to report the presence of captured compounds, these reporter antibodies can be used directly, for example in label-free biosensors, or as conjugates with reporter molecules, such as enzymes, fluorophores or nanoparticles, depending on the assay type and the platform used for the read-out. Recent advances in the miniaturization of analytical systems, as well as newly emerging technologies, offer alternatives for traditional immunoassays in the configuration of platforms with high automation and multiplexing capabilities. These include bead-based immunoassays, where the exteriors of the beads provide the surface on which an immunoassay is performed.