Bimetallic AuPt nanochains: Synthesis and their application in electrochemical immunosensor for the detection of carcinoembryonic antigen

The recent development in the nanotechnology has paved the way for a large number of alloyed nanomaterials and devices of desirable properties which have useful functions for electrochemical sensor and biosensor applications. In this paper, bimetallic AuPt nanochains were synthesized through a mild chemical method, with which anti-horseradish peroxidase-conjugated anti-carcinoembryonic antigen (HRP-anti-CEA-NCAuPt) was developed for electrochemical detection of carcinoembryonic antigen (CEA) in a sandwich-type immunoassay format. The alloyed nanocrystals exhibit not only sound signal amplification effect of Au nanoparticles, but also further new combination of interfacial, electrical and structural properties arising from the disparate AuPt components. As a result, the electrochemical signal was significantly amplified by using the HRP-anti-CEA-NCAuPt as tracer and hydrogen peroxide as enzyme substrate. The linear range of the developed immunosensor is 0.01–200 ng/mL and the detection limit is 0.11 pg/mL of CEA, which makes the biometallic nanochains promising candidates for the next-generation sandwich-type electrochemical immunoassays.