Nanobody primary antibodies are recombinant single-domain antibodies that directly recognise a specific target antigen. Derived from the variable domain (VHH) of camelid heavy-chain antibodies, an unconjugated monomeric nanobody typically has a molecular weight of approximately 15 kDa. These compact antigen-binding reagents provide an alternative format to conventional primary antibodies for protein detection, localisation and capture.

Features of Nanobody Primary Antibodies

Nanobodies recognise their target through a single variable domain, without requiring paired heavy and light chains. Their compact size can improve access to sterically restricted epitopes and, when directly labelled, reduce the distance between the target antigen and the detection label. Binding affinity, specificity and compatibility with sample preparation depend on the individual clone and require application-specific validation.

Applications of Nanobody Primary Antibodies

• Immunofluorescence and protein localisation: detecting target proteins in appropriately prepared cells or tissues using nanobodies validated for the relevant fixation and staining conditions.
• Super-resolution microscopy: directly labelled nanobodies can minimise the separation between the fluorophore and the target, supporting precise protein localisation.
• Protein capture and immunoprecipitation: immobilised nanobodies can enrich target proteins and associated interaction partners for subsequent biochemical analysis.
• Other immunodetection assays: selected clones may be suitable for Western blotting, ELISA or flow cytometry when explicitly validated for these applications.

Choosing the Appropriate Detection Format

Nanobody primary antibodies may be supplied as unconjugated reagents, directly labelled conjugates or fusion constructs. Directly labelled formats enable detection without a secondary antibody. Unconjugated VHH reagents generally require a compatible anti-VHH or anti-tag detection reagent, as conventional anti-IgG secondary antibodies may not recognise them. Selection should consider target reactivity, validated applications, conjugation and the planned detection method.