These streptavidin-coated magnetic beads are uniform particles and are available in the following diameters: 0.6 µm, 1 µm and 3 µm. Magnetic beads are provided in a 1% (10 mg / mL) aqueous solution with additives ^[1].

The surface of the magnetic beads are covalently coated with streptavidin protein. The specificity and strength of the streptavidin-biotin interaction is well established, with each streptavidin tetramer capable of binding four biotin molecules, with a dissociation constant (K_d) of approximately 10^-14 mol/L ^[2]. This allows for fast and specific capture of targets labeled with biotin, such as oligonucleotides, peptides, proteins and antibodies.

The usage of magnetic beads greatly streamlines the purification of crude samples. Simply incubate with target analytes, retain beads using a magnet, while washing unbound contaminates from the sample tube. An elution buffer can subsequently be used to recover captured biomolecules. Compared to other methods of purification, streptavidin magnetic beads can be seamlessly integrated into automatic sample preparation systems and high-throughput screening (HTS) applications.

[1] Storage buffer contains 10 mM Tris (pH 7.4), 0.1% BSA, 0.05% Tween-20 and 0.1% ProClin 300.
[2] https://www.aatbio.com/catalog/biotin-and-streptavidin