Ultra bright label for lateral flow up to 20 increases in lateral flow diagnostic sensitivity over 40 nm gold. Streptavidin tetramer is covalently bound to the particle surface via an amide bond. Streptavidin gold conjugates can be used for convenient conjugation of any biotiny lated antibody, protein or oligonucleotide. Provided at 10 OD in an aqueous conjugation buffer composed of 0.1 PBS, 0.5% BSA, and 0.05% azide PROTOCOLS Bio ready Streptavidin Gold Conjugation Protocol Antibody Purification