The ALFA system

NanoTag’s proprietary technology called “Celline” allows for the straightforward discovery of single-domain antibodies by affinity purification of target-specific B lymphocytes from a pool of PBMCs.
Using a single selection step, Celline drastically speeds up sdAb candidate selection while at the same time allowing to set avidity/affinity boundaries.
This method has a proven record for the fast generation of high affinity and low-affinity binders.

A unique, patented technology based on three single-domain antibodies recognizing a rationally designed epitope tag of only 14 amino acids.
Covering a range from pM to nM affinities, this highly specific sdAb ensemble allows for an unmatched spectrum of applications.
High-resolution imaging in life or fixed cells, immobilization and affinity purification of functional proteins and protein complexes, and even therapeutic applications – everything is possible!

A set of single-domain antibodies recognizing conventional immunoglobulins with exquisite species and isotype specificity is the core of our patented technology.
Our secondary tools provide unique benefits for all antibody-based assays in research and diagnostics by combining reproducible specificity and production with small and high-affinity monovalent binding.
In addition, our technology offers surprising new possibilities like one-step indirect immunofluorescence or easy multiplexing.

FluoTag^® is NanoTag’s trademark for camelid single-domain antibodies conjugated to chemical fluorophores.
All FluoTags^® carry a defined number of fluorophores at known positions. Accordingly, they are available as FluoTag^®-Q (one fluorophore; Quantitative) or coupled to multiple fluorophores (FluoTag^®-X2 or FluoTag^®X4).
Together with their monovalent binding mode, the defined fluorophore conjugation of FluoTags^® results in a more quantitative and reliable readout in all fluorescence-based analyses.

Our sdAbs can be equipped with fixation (FX) cassettes, short amino acid stretches featuring multiple primary amines.
FX cassettes significantly improve the post-fixation properties of sdAbs, which is beneficial for extended experimental procedures, e.g. STORM and DNA-PAINT microscopy.
In addition, FX cassettes provide multiple anchor points in a ProteinaseK-resistant environment and therefore improve the retention of fluorophores in expansion microscopy (ExM) applications.

Selector resins are affinity resins based on controlled immobilization of single-domain antibodies.
For production, high-quality agarose and magnetic-agarose resins are functionalized in-house using proprietary chemistry. This results in both a highly specific, stable, and oriented sdAb attachment and an ultra-low non-specific background binding.
The precise and oriented chemistry also ensures optimal functionality and accessibility of the sdAbs and therefore results in beads with a high capacity.

A fusion of a single-domain antibody to an immunoglobulin Fc domain results in a recombinant heavy-chain antibody (rHcAb). Such divalent recombinant antibodies provide maximal flexibility for technologies based on conventional Fc domains, like, e.g., classical secondary amplification systems.
HcAbs can, however, also be detected using our Secondary nanobodies.

Conventional secondary antibodies are multivalent and therefore form large clusters with primary antibodies.
In contrast, our species-specific secondary nanobodies are monovalent binders and therefore form defined stoichiometric complexes with primary antibodies in solution.
This feature efficiently prevents cluster formation. Primary antibodies and secondary nanobodies can therefore be pre-mixed or even co-incubated on the sample and thus enable convenient one-step immunofluorescence or Western assays.

Due to their monovalent high-affinity binding, NanoTag’s species and isotype-specific secondary nanobodies allow multi-color fluorescent assays using multiple primary antibodies raised in the same species.
Multiplexing thereby drastically expands the possible combinations of primary antibodies and at the same time comes with extra features like a time-saving one-step protocol and an increased imaging resolution.
Discover the new freedom in all multi-color fluorescent assays!

Bi-specific sdAb fusions (diabodies) are often used as adaptor molecules bringing two individual target molecules in tight contact.
A fusion of two sdAbs targeting the same molecule at different sites may also be used to increase the apparent binding affinity.
NanoTag has first-hand experience in the design, cloning, and expression of bi-specific sdAb fusions in prokaryotic- and eukaryotic systems and provides ready-to-use vector systems.