Preparation of nanoparticles conjugated with enzyme and antibody and their use in heterogeneous enzyme immunoassays

Enzyme conjugates suitable for enzyme-linked immunosorbent assays can be conveniently prepared by binding enzyme and antibody to nanoparticles. Peroxidase and antitransferrin or anti-alpha-fetoprotein were co-immobilized to tresyl activated 40 nm silica particles and the particle conjugates used in heterogeneous enzyme immunoassays for the evaluation of transferrin and alpha-fetoprotein within the concentration range 0.25-1000 ng/ml.