Multifunctional mesoporous silica nanoparticles as sensitive labels for immunoassay of human chorionic gonadotropin

A novel method to construct amperometric immunosensor for human serum chorionic gonadotrophin (hCG) has been described. In this study, horseradish peroxidase (HRP), Pt nanoparticles and secondary antibody (Ab2) modified MSN (Pt@MSN/HRP/Ab2) was synthesized and the multifunctional MSN was used as label for the preparation of immunosensor. With the hCG primary antibody immobilized onto thionine/graphene modified glassy carbon electrode (GCE) via crosslinking with glutaraldehyde, the electrochemical immunosensor was able to realize a reliable determination of hCG in the range of 0.01–12 ng mL−1 with a detection limit of 7.50 pg mL−1. This immunoassay system has many desirable merits including high sensitivity, accuracy, and little instrumentation requirement. Significantly, the new method may be quite promising, with potentially broad applications for clinical immunoassays.