Which biotin-free BSA do you recommend for use with Streptavidin MicroBeads?

For magentic labeling, use biotin-free labeling buffer only, for example, buffer without BSA or buffer supplemented with biotin-free BSA. If the BSA preparation is contaminated with biotin, free biotin competes with biotinylated antibody for the binding of the Strepatavidin MicroBeads.

Alternatively, you can use Anti-Biotin MicroBeads, which do not bind to free biotin.