Electroactive Fe3O4/α-Fe2O3@Au nanocomposites driven label-free electrochemical aptasensor with magnetic self-assembly for rapid quantification of alpha-fetoprotein

Alpha-fetoprotein (AFP) is a crucial biomarker for several cancers’ diagnosis, especially hepatocellular carcinoma; therefore, early accurate detection of AFP is of vital significance. Herein, a label-free electrochemical aptasensor with magnetic self-assembly of heterogeneous Fe₃O₄/α-Fe₂O₃ nanosheets is presented for rapid and accurate detection of AFP. The sensor was mainly designed by loading Au nanoparticles (AuNPs) on the surface of Fe₃O₄/α-Fe₂O₃ nanosheets and further binding with aptamer probes through Au–S bonds, and the target could be captured by the high affinity and specificity with the aptamer. Furthermore, owing to the excellent superparamagnetization of Fe₃O₄/α-Fe₂O₃@Au nanocomposites, rapid magnetic separation and magnetic self-assembly could be realized, actualizing quantitative determination of AFP through current changes. Under optimal conditions, the aptasensor exhibited excellent quantitative determination performance in the 10 pg/mL to 1 μg/mL range, and the detection limit was 1.31 pg/mL. In addition, the aptasensor demonstrated favorable reproducibility, stability, selectivity, and achieved satisfactory recovery (97.34–104.60%) in human serum samples, providing a practical strategy for clinical detection of AFP.

Graphical Abstract