Chemiluminescence immunoassay based on dual signal amplification strategy of Au/mesoporous silica and multienzyme functionalized mesoporous silica

摘要

A chemiluminescent dual signal amplification strategy for the determination of ct-fetoprotein (AFP) was proposed based on a sandwich immunoassay format. Monoclonal antibody of AFP immobilized on the gold nanoparticles doped mesoporous SiO_2 (Au/SiO_2) were prepared and used as a primary antibody. Horseradish peroxidase (HRP) and HRP-labeled secondary antibody (Ab_2) co-immobilized into the mesoporous SiCb nanoparticles (HRP-Ab_2/SiO_2) were used as the labeled immunological probe. Due to the high ratio surface areas and pore volumes of the mesoporous SiO_2, not only the amount of AFP monoclonal antibody but also the amount of the modified HRP and Ab_2 in HRP-Ab_2/SiO_2 were largely increased. Thus the chemiluminescent signal was amplified by using the system of luminol and H_2O_2 under the catalysis of HRP. Under the optimal conditions, two linear ranges for AFP were obtained from 0.01 to 0.5 ng mL~' and 0.5 to 100ngmL1 with a detection limit of 0.005 ngmL1 (3ct). The fabricated signal amplification strategy showed an excellent promise for sensitive detection of AFP and other tumor markers.