A magnetically induced self-assembled and label-free electrochemical aptasensor based on magnetic Fe3O4/Fe2O3@Au nanoparticles for VEGF165 protein detection

Based on magnetic Fe 3 O 4 /Fe 2 O 3 @Au nanoparticles (Fe 3 O 4 /Fe 2 O 3 @Au NPs), to detect an important tumor screening marker, vascular endothelial growth factor 165 (VEGF 165 ), a label-free electrochemical aptasensor was constructed. Magnetic glassy carbon electrode (MGCE) after Fe 3 O 4 /Fe 2 O 3 @Au NPs surface modification by a magnetic-induced self-assembly technique was the platform. Fe 3 O 4 /Fe 2 O 3 @Au NPs were used as the signal amplifier to enhance electron transfer, which was essential for the detection of trace amounts of biological analytes, and were prepared via heating hydrolyzation-combustion calcination and trisodium citrate reduction. Meanwhile, aptamers bound to the as-prepared nanomaterial via Au-s bonds and specifically recognized VEGF 165. The electrochemical properties of the aptasensor were evaluated with [Fe(CN) 6 ] 3−/4 − as redox probes. When in optimal detection conditions, an excellent linear relationship (between 0.01 and 10 pg mL −1 , R 2  = 0.9973) was obtained for the electrochemical aptasensor. The limit of detection (LOD) and the limit of quantitation (LOQ) of the electrode were 0.01 and 0.03 pg mL −1 . This proposed aptasensor exhibited favourable selectivity, stability, reproducibility, and regenerability. The results demonstrated that the sensor was promising to provide an efficient, accurate, and low-cost auxiliary detection method for the early screening of VEGF 165 -related diseases, which had important clinical practical value for the research of human precision medicine.