A Multimode Biosensor Based on Prussian Blue Nanoparticle Loaded with Gold Nanoclusters for the Detection of Aflatoxin B1

Herein, a novel fluorescent/colorimetric/photothermal biosensor is proposed for aflatoxin B1 (AFB1) detection in food based on Prussian blue nanoparticles (PBNPs) (~50 nm), gold nanocluster (AuNCs) and aptamer (Apt) within three hour. Briefly, a multifunctional compound namely PBNPs-PEI@AuNCs is synthesized by PBNPs as the loading carrier, polyethyleneimine (PEI) as the crosslinking agent, and AuNCs directly combined on the surface of PBNPs. And AFB1 Apt is then modified on PBNPs-PEI@AuNCs to form PBNPs-PEI@AuNCs-Apt probe. When AFB1 is present, AFB1 is specifically captured by the probe. Meanwhile, the MNPs@antibody is also introduced to capture AFB1, thereby forming the “sandwich” structure compound. After magnetic separation, high temperature was conducted to this “sandwich” structure compound to induce the denaturation of Apt. And then fluorescent/colorimetric/photothermal signals are collected from the PBNPs-PEI@AuNCs@Apt in its related condition. The detection limits of the biosensor are 0.64 × 10-14, 0.96 × 10-14 and 0.55 × 10-12 g/mL, for three signals, which are output independently and can be verified with each other to ensure the accuracy of the results. Moreover, the colorimetric and photothermal strategies do not require large-scale instruments, providing a promising choice for achieving rapid field detection of AFB1.