An immunomagnetic separation and bifunctional Au nanoparticle probe-based multiamplification electrochemical strategy.

A novel electrochemical magnetoimmunosensor for the rapid and sensitive detection of carcinoembryonic antigen (CEA) was fabricated based on a combination of high-efficiency immunomagnetic separation, bifunctional Au-nanoparticle (bi-AuNP) probes, and enzyme catalytic amplification. The reaction carrier magnetic beads (MBs) effectively reduced the toxicity of the complex sample to the working electrode, and the signal carrier bi-AuNP probes loaded a large amount of signal molecules, both of which enhanced the signal-to-noise ratio and further improved the detection sensitivity. A detection limit as low as 0.11 pg/mL was achieved for CEA detection based on the immunomagnetic separation and bi-AuNP probe-based multiamplification strategy, and the strategy was further successfully applied in human serum samples. The transducer was regenerated via a simple washing procedure, which enabled the detection of all samples on a single electrode with high reproducibility. The proposed strategy, which has the merits of high sensitivity, selectivity, and reproducibility exhibits great potential for detection in complex samples.