Hollow platinum decorated Fe3O4 nanoparticles as peroxidase mimetic couple with glucose oxidase for pseudobienzyme electrochemical immunosensor

In this paper, a novel dual signal amplification strategy was proposed based on hollow platinum nanoparticles decorated Fe3O4 nanoparticles (HPtNPs-Fe3O4) and glucose oxidase (GOD) for sensitive detection of α-1-fetoprotein (AFP). In such system, HPtNPs-Fe3O4 couples with glucose oxidase to form a pseudobienzymatic system because both HPtNPs and Fe3O4 nanoparticles (NPs) have peroxidase-like catalytic activity and this peroxidase mimetic is more stable and economical than natural peroxidases. With the employment of bovine serum albumin (BSA), the biocompatibility, stability and water solubility of Fe3O4 NPs was further enhanced. The BSA functionalized Fe3O4 NPs provided lysine groups to immobilized HPtNPs, antibodies and GOD, which further amplified the detection signal. The results show that the sensor exhibited attractive redox electrochemical activity and high catalysis activity when detected in the working buffer containing 3.6 mM D-glucose. The electrochemical immunosensor exhibited a linear range of 0.01–60 ng/mL with a low detection limit of 1.6 pg/mL.