Santuarios portugueses en las Cantigas de Santa María

Abstract

Determination of squamous cell carcinoma antigen (SCCA) in human serum plays an important role in diagnosis of cervical squamous cell carcinoma. In this work, Au/Ag/Au core/double shell nanoparticles (Au/Ag/Au NPs) were prepared by a simple approach and were used as novel enzyme-mimetic labels for development of a sandwich-type electrochemical immunosensor for SCCA. The nanostructure of Au/Ag/Au NPs could be well confirmed by transmission electron microscope (TEM) and UV-vis spectra. Au NPs decorated mercapto-functionalized graphene sheets (Au@SH-GS) were used as platform for immobilization of primary antibody (Ab1), while Au/Ag/Au NPs were employed as labels of secondary antibody (Ab2). Due to the excellent electrocatalytic activity of Au/Ag/Au NPs towards the reduction of hydrogen peroxide (H2O2), electrochemical amperometric responses to SCCA were achieved after the immuno-reaction. Under optimum conditions, the electrochemical immunosensor exhibited a wide linear range from 0.5 pg/mL to 40 ng/mL with a low detection limit of 0.18 pg/mL for SCCA. The designed immunosensor displayed an excellent analytical performance with good reproducibility, high selectivity and stability.