Streptavidin and Neutravidin offer a powerful and universal instrument as biotin binding surfaces (Antibodies – Antigens – Peptides – Polysaccharides – Oligonucleotides – DNA fragments – etc.) and are suitable to set up different kind of immune-molecular tests.
Biotin is a small molecule (M.W. 244 Da) which can be conjugated to many proteins without losing or altering their activity and each protein can bind many biotin molecules.

Biotin Binding Surfaces Characteristics
Biomat biotin-binding 96-well coated plates include:
- Streptavidin Coated 96-Well Plates
- Streptavidin High Binding Coated 96-Well Plates
- Neutravidin Coated 96-Well Plates
Biomat biotin-binding PCR products include:
- Streptavidin PCR 8 Strip Tubes
- Streptavidin HB PCR 8 Strip Tubes
- Streptavidin PCR Plates
- Streptavidin HB PCR Plates
Streptavidin is a tetrameric protein (M.W. 60 kDa) with very high affinity for biotin (Ka=10-15 M); the bond is the strongest known non-covalent biological interaction.
Neutravidin is a deglycosylated avidin (M.W. 60 kDa) that contains four identical subunits biotin-binding with very high affinity for biotin (Ka= 10-15 M). It has an isoelectric point near-neutral (pI=6.3) and the lowest nonspecific binding properties among the known biotin binding proteins. Compared to the streptavidin, neutravidin in its primary structure does not contain the RYD sequence (Arg-Tyr-Asp). The lack of that kind of sequence totally eliminates the possibility to interact with the RGD sequence (Arg-Gly-Asp) present in the membrane receptors of a large variety of cells.
Streptavidin and Neutravidin coated plates offer greater assay’s sensitivity given that each of their four subunits binds one molecule of biotin.
Surfaces:
The streptavidin/neutravidin-biotin bonding main features are:
- stability
- specificity
- affinity
These bonding characteristics are useful for special applications of molecules which do not offer reliable bonding by passive adsorption or adsorb in an unfavorable orientation.
Applications
Which are the applications of biotin-binding surfaces such as Streptavidin and Neutravidin?
ELISA sandwich assay test: among the different ELISA tests for the dosage of antigens (e.g. TSH) this test offers high sensitivity performance and proper reactivity. However, it requires that one of the two antibodies is bound directly to the microplate (medium or high binding) requiring an antibody coating concentration of at least 3 µg/ml. By using a streptavidin or neutravidin* coated microplate, after the biotinylation of the catcher antibody, it is possible to obtain the same sensitivity and reactivity performance with 0,5 – 1 µg/ml of antibody saving a significant amount of product. Furthermore, the attack of the biotinylated antibody is sterically more favored to react with the antigen and consequently favors the sandwich with the detector antibody.
Indirect ELISA test: binding a low molecular weight peptide directly to the microplate is limiting and difficult on medium or high binding microplates. It is more effective and easy to biotinylate the peptide and to bind it to the streptavidin or neutravidin* microplate.
Competitive ELISA test: in the competitive test the anti-molecule biotinylated antibody, which must be present in a limited concentration, can be bound to the streptavidin or neutravidin* microplate to guarantee the correct competition between the dosed molecule and the analogous enzyme labeled molecule.
PCR-ELISA test: streptavidin or neutravidin* microplate may be used to set up a PCR-ELISA test, taking advantage of the high specificity and stability established in the binding of biotinylated oligonucleotide during the hybridization step.
*Neutravidin coated surfaces are suitable for the same type of applications offering a lower background.