Magnetic nanoparticles-based immunoassay for aflatoxin B1 using porous g-C3N4 nanosheets as fluorescence probes

With the porous g-C3N4 nanosheets (pg-CNNSs) as fluorescence probes and AFB1-bovine serum albumin conjugate modified Fe3O4 magnetic nanoparticles (MNPs) as immunosensing probes, a simple sensitive aflatoxin B1 (AFB1) detection method was first constructed. Based on the simple preparation method, the excellent biocompatibility, strong fluorescence emission and proper emission wavelength, pg-CNNSs were first functionalized by AFB1 antibody as fluorescence probes, which can bind with MNPs through antigen-antibody immunoreaction to form the pg-CNNSs-MNPs complexes. After magnetic separation, the fluorescence intensity of the complexes was tested. The target analyte (AFB1) can interfere the above immunoreaction by direct competition with immunosensing probes, and lead to the signal decreased. The detection limit for AFB1 was as low as 0.002 ng mL−1 under optimal conditions. Additionally, the applicability of this method was also confirmed in adulterated maize samples.