Irregularly shaped gold nanoparticles as secondary labels for enhanced electrochemical sandwich-type enzyme immunoassay for the determination of biomarkers

This letter describes a dual-amplified electrochemical sandwich-type enzyme immunoassay for the cancer antigen 125 (CA125) by using irregularly shaped gold nanoparticle-labeled horseradish peroxidase (HRP)-bound anti-CA125 as secondary antibodies. Compared with conventional sandwich-type immunoassays, the proposed immunoassay exhibits a low detection limit and wide linear range.