Gold conjugated SpA

SpA-gold is gold conjugated Staphylococcal Protein A (rSPA), the colloid gold size is

40nm before conjugation. SpA-gold can be applied to gold pad binding to human IgG in

diseased blood sample,  forming SpA-gold-human IgG complex, the complex then run

from gold pad to nitrocellulose membrane to interact to the specific antigen over the test

line. It is one way to develop the lateral flow assay to test the specific antibody induced by

infectious diseases.