Construction of a “Signal On” Electrochemical Immunosensor Based on Light Induction

The activity and stability of nanoprobes, which play an important role in electrochemical immunosensors, are still controversial topics. In this study, we report the design and development of a new type of nanoprobe for detecting carcinoembryonic antigen (CEA). First, molybdenum copper sulfide (Cu2MoS4) with peroxidase activity is prepared by using cuprous oxide (Cu2O) as a self-sacrificing template, which can carry out effective mass transfer in the Fenton-like reaction. The Cu2+ produced by this reaction can be captured by ethylene diamine tetraacetic acid (EDTA). More importantly, near-infrared (NIR) laser irradiation can significantly improve the efficiency of the Fenton-like reaction, thereby achieving "signal on". The peak current response is improved by 265% in 5 min. The immunosensor for CEA shows a wide linear range between 0.1 pg/mL and 80 ng/mL, with a low limit detection (LOD) of 3.3 fg/mL. Not only does our work provide the first example for the application of Fenton metal sulfide nanomaterials in biosensors, but also an easy-to-manufacture immunosensor has been proposed, which has broad prospects in clinical diagnosis.