KCS

QD functionalized silica nanoparticles was developed for application of immunosensor using nonbiofouling, pre-activated polymers coated substrates for cancer marker detection. In this work, we synthesized random copolymers having three important groups: anchoring sites, serving to attach the COC substrate; a PEG component, which acts as a repellent of non-specific biomolecules; and an NHS ester group for conjugation of biomolecules. For sandwich immunoassays, anti-α-fetoprotein (Anti-AFP) as capture antibody was covalently immobilized on the substrate through the polymer layers. Furthermore, we prepared anti-AFP/QD-coated silica nanospheres conjugates for signal amplification. Sandwich-type immunoassays were carried out on the polymer coated COC surfaces using AFP (liver cancer marker). Using the optimized assay, the red fluorescence response to AFP was linear over a range from 0.1 to 100 ng/ml.