A Fluorescent Aptamer Sensor for Detecting Golgi Protein 73 Based on Magnetic Ferroferric Oxide@Boron, Nitrogen‐Doped Graphene Quantum Dots

In this paper, a fluorescent aptamer sensor based on magnetic ferroferric oxide@boron, nitrogen-doped graphene quantum dots (Fe₃O₄@B,N-GQDs) was developed to detect Golgi protein 73 (GP73). GP73 aptamer (GP73_Apt) functioned with Fe₃O₄@B,N-GQDs (Fe₃O₄@B,N-GQDs-GP73_Apt) and was used as the fluorescent donor, while molybdenum disulfide (MoS₂) with a large surface served as the fluorescent acceptor. The fluorescence of Fe₃O₄@B,N-GQDs-GP73_Apt was quenched by MoS₂ based on the fluorescence resonance energy transfer (FRET) principle. However, in the presence of GP73, Fe₃O₄@B,N-GQDs-GP73_Apt could specifically bind to GP73, forming a Fe₃O₄@B,N-GQDs-GP73_Apt-GP73 complex. This binding event caused Fe₃O₄@B,N-GQDs-GP73_Apt to move away from the surface of MoS₂, thus blocking the FRET process and recovering the fluorescence. Under optimal conditions, a linear relationship was established between the fluorescence recovery and the concentration of GP73 within the range of 10-1000 ng/mL (R²= 0.9918), and the limit of detection was 7.37 ng/mL. Additionally, when the sensor was applied to test actual samples, the recovery rates were in the range of 98.80%-101.18%, and the relative standard deviations were between 0.29%-3.04%. These findings demonstrated the excellent detection performance of the proposed fluorescent aptamer sensor.