Spot-Label

Made for immunofluorescence and Western analyses
Spot-Labels are very small, highly specific anti-Spot-Tag binding proteins covalently coupled to bright and stable fluorescent dyes. These anti-Spot binding proteins are derived from a single-domain alpaca antibody fragment (just 14kDa) called a Nanobody. Conventional protocols for labeling with antibodies usually require a sandwich technique, in which the primary antibody binds the target molecule and a “labeled” secondary antibody is added later to visualize the location of this molecule (whether on a blot or on a slide). These multi-step protocols are long, suffer from unwanted background, and can result in non-specific targeting and low signal. By comparison, Spot-Labels are much smaller, resulting in stronger and more precise binding kinetics.

The recombinantly expressed single-binding domain Spot-Label (monovalent) is optimized for use with Western blots. The bivalent form of Spot-label offers incredible performance in standard immunofluorescence (IF) microscopy. The reason? These tiny fluorescent labels can penetrate more easily, and bind more effectively, than traditional monoclonal antibodies that are over 10 times its size. The Spot-Label/Spot-Tag system is the first peptide-tag/Nanobody system applied in Super Resolution Microscopy. Due to their small size, Nanobodies are particularly suitable for effective labelling with minimal fluorophore displacement for super-resolution microscopy. For relative comparison of the sizes of both affinity reagents, see the schematics to visualize why size matters.