The Affibody® molecule is a key component of the company’s technology. In contrast to antibodies, Affibody® molecules are composed of alpha helices and lack disulfide bridges. Yet, they mimic monoclonal antibodies, and in addition offer several unique properties making them a superior choice for a number of targeted therapeutic, diagnostic imaging and biotechnological applications.

Small Size (1/25th the Size of a Monoclonal Antibody)
The size of the Affibody® molecules is only 6 kDa.

Robustness (Withstand Harsh Conditions)
Affibody molecules have been shown to withstand extreme conditions, such as high temperatures (90°C) or acidic and alkaline conditions (at pH 2.5 or pH 11, respectively)

Rapid and Reversible Folding (Extreme Stability)
Affibody® molecules do not contain cysteines or disulfide bridges, and fold very rapidly into a correct three dimensional structure. Temperatures above the melting temperature have been used in some studies, with retained binding properties following return to ambient conditions.

Flexible Low Cost Production (Synthesis or Recombinant)
Chemically synthesized Affibody® molecules fold spontaneously following removal of the protection groups. Due to its small size and bacterial origin, Affibody® molecules can also be produced at large scale in bacterial systems.

Flexible Engineering and Formatting (Modified Properties)
The engineering flexibility enables tailor-making molecules for different applications. Head-to-tail fusions of Affibody® molecules of the same specificity have proven to give avidity effects in target binding, and head-to-tail fusion of Affibody® molecules of different specificities makes it possible to get bi- or multi-specific affinity proteins. Fusions with other proteins are also readily created. Moreover, a site for site-specific conjugation is facilitated by introduction of a unique cysteine at a desired position.

High Selectivity and Affinity (High Potency)
Binders with nanomolar affinity are routinely obtained from naïve library selections, and binders with picomolar affinity have been obtained following affinity maturation.

Powerful Complement to Conventional Treatments
There are several potential benefits with the Affibody® technology compared to traditional methods, including favorable diffusion and tumor penetration resulting from the small size. Affibody® molecules are superior to monoclonal antibodies as carriers of toxins or therapeutic radionuclides because of the absence of non-target interactions, such as the Fc-receptor interactions of the antibody. This means that the toxic substance destroys the tumor with minimal damage to surrounding tissue.