Nano-Secondaries: ChromoTek’s New Alpaca Secondary Antibodies
ChromoTek’s first available Nano-Secondary comes as a mixture of two nanobodies that bind to rabbit IgG (anti-Fc and anti Fab VHH) and are conjugated to one of three Alexa Fluor® dyes. Each nanobody carries two fluorophores, resulting in stochiometric labelling of each primary rabbit antibody with eight fluorophores. As these monovalent antibodies do not cluster, they can be used in one-step immunostaining (see image below).
Thanks to their small size — Nano-Secondaries are about ten times smaller than regular secondary antibodies — the displacement of the fluorophore to the epitope is very small, allowing you to get a better image resolution. In addition, their small size generally allows better tissue penetration. Nano-Secondaries have also been tested against the antibodies and sera of multiple species, making them ideal for use in multiplexing. They do not bind to mouse, rat, goat and sheep (although they do show cross-reactivity to human and macaque serum). As these secondary antibodies have a high affinity to rabbit IgG antibodies, they can detect even small amounts of epitope and reduce background noise.