A novel split PEC sensor based on magneto–optic nanostructure and photocurrent polarity switching strategy

Photoelectrochemical (PEC) sensors have attracted much attention due to their low cost, simple instrumentation and high sensitivity. However, conventional PEC sensors require layer–by–layer modification of the photoelectrode surface, which has the disadvantages of being time–consuming and unstable. In addition, complex interfering substances in real samples may lead to false–positive or false–negative detection results. It was thought that the above drawbacks could be eliminated by the construction of a polarity inversion PEC sensor. In this work, a magnetically separated PEC sensor was constructed for the detection of Carcinoembryonic antigen (CEA). During the experiment, the construction of the sensor was used for sensitive detection of CEA. In the experimental process, Fe3O4@SiO2@CdS, a semiconductor material with magnetic properties, was chosen as the substrate material, and ZnO/CuO was used as the marker on the DNA2 molecule, and a split magnetic separation PEC sensor was constructed, which was used to realize the sensitive detection of CEA. Eventually, the detection range of the sensor for CEA detection is 1 ∼ 10000 pg/mL, with the detection limit of 0.34 pg/mL. Additionally, the PEC sensor has the advantages of high speed, high efficiency, high sensitivity, good specificity, and high stability. The sensing platform constructed in this work can also be extended to detect other targets, which provides a new idea for photochemical sensing platforms. In this experiment, we developed a split PEC sensor based on magneto–optic nanostructure and photocurrent polarity switching strategy. Specifically, the proposed magnetic nanostructure Fe3O4@SiO2@CdS–DNA1 exhibits good paramagnetism and dispersion ability. By magnetic separation process, the PEC signals of opposite polarity can be obtained.