Nano-Secondaries — very precise secondary antibodies

Mid 2019, ChromoTek ‘Home of Alpaca Antibodies’ brought their first Nano-Secondary onto the market: anti-rabbit IgG, conjugated to an AlexaFluor® dye. Since then, they have expanded the Nano-Secondary line with three different subclass-specific anti-mouse IgG antibodies.

• 10x smaller than conventional secondary antibodies: better resolution, better tissue penetration, great for one-step immunostaining and multiplexing
• Verified: recombinant, sequenced, well tested, animal-free production, no batch-to-batch variation
• For IF, WB, and super-resolution microscopy
• Anti-rabbit IgG, anti-mouse IgG1: also flow cytometry

Nano-Secondaries are alpaca nanobodies conjugated to fluorescent dyes (Alexa Fluor® 488, 568 or 647). They bind specifically to primary antibodies and are much smaller in size compared to conventional secondary antibodies. As a result, the disparity between fluorescence signal and target antigen is much smaller.

In one-step immunostaining, primary and secondary antibodies are pre-mixed and added to the sample together. With conventional secondary antibodies, these bivalent antibodies can form large complexes, which interfere with proper target access and tissue penetration. In addition, precipitated deposits can lead to false signals or artefacts. Nano-Secondaries circumvent these problems thanks to their small size. They can be pre-mixed with primary antibodies and perform equally well in one-step immunostaining as in sequential immunostaining (figure on right). With Nano-Secondaries, no pre-incubation with the primary antibody is necessary (a protocol by ChromoTek can be found here).