InnovaCoat® GOLD - 40nm Streptavidin gold conjugate (10OD)
40nm Streptavidin gold conjugate (10OD)InnovaCoat® GOLD nanoparticles have a proprietary surface coating which covalently binds antibodies, proteins, peptides or any other biomolecule with free amine groups to form highly stable conjugates. The surface coating can withstand the most extreme conditions (e.g. 2.5M NaOH at 70oC for 2 hours), making InnovaCoat® GOLD an ideal reagent for a wide range of applications.
Our InnovaCoat® GOLD streptavidin conjugates share the stability attributes of the core nanoparticle. Furthermore, since the streptavidin is covalently bound to the surface coating of the gold nanoparticle it is unable to desorb, which is a major problem faced by competing products in which the streptavidin is directly attached to the metal.
Streptavidin gold nanoparticle conjugates can be used in conjunction with biotinylated reagents such as biotinylated antibodies or proteins, in applications such as lateral flow immunoassays or electron microscopy.
Technical TipWhen using a streptavidin gold nanoparticle conjugate as the detection reagent in a lateral flow immunoassay, it is essential to optimize the amount of biotinylated antibody. The following example shows a lateral flow strip with goat anti-rabbit antibody immobilized at the test line, and biotin immobilized at the control line. The streptavidin gold nanoparticle conjugate has been dried in to the conjugate release pad. Varying concentrations of biotinylated rabbit IgG antibody have been added to the sample application pad.
- Scenario 1 – biotinylated rabbit IgG (50-100 µg/ml) has bound to the streptavidin gold nanoparticle conjugate to produce a strong signal at the test line.
- Scenario 2 – excess biotinylated rabbit IgG (>400 µg/ml) has resulted in competition for binding to the test line between biotinylated rabbit IgG, and biotinylated rabbit IgG which is bound to the streptavidin gold nanoparticle conjugate. The signal at the test line is weak.
- Scenario 3 – A low level of biotinylated rabbit IgG results in a weak test line but a strong control line.
Streptavidin is purified from the bacterium Streptomyces avidinii. It is a tetrameric protein that is composed of identical subunits, with the tetramer having a molecular weight of approximately 53kDa. Each subunit binds one biotin molecule with a very high degree of specificity and affinity. The Kd for this interaction is in the region of 10-15M.
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