Electrochemical Detection of Alpha-Fetoprotein Based on Black Phosphorus Nanosheets Modification with Iron Ions.

Black phosphorus nanosheets (BPNSs) were synthesized with liquid exfoliation combined with the ultrasonic method and loaded with Fe by simply mixing. The morphology, structure and electrochemical properties of the synthesized Fe/BPNSs were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV), etc. The load of Fe can improve the electrochemical performance of BPNSs and enhance the sensitivity of the detection. Additionally, Fe/BPNSs display good biocompatibility. In this study, immunosensors based on Fe/BPNSs were constructed to detect alpha-fetoprotein (AFP). The detection is due to the specific binding between the AFP antigen and antibody on the surface of the immunosensors, which can reduce the current response of Fe/BPNSs. The immunosensors have a good linear relationship in the range of 0.005 ng·mL to 50 ng·mL, and the detection limit is 1.2 pg·mL. The results show that surface modification with metal ions is a simple and effective way to improve the electrochemical properties of BPNSs, which will broaden the prospects for the future application of BPNSs in the electrochemical field.