A highly sensitive photothermal immunochromatographic sensor for detection of aflatoxin B1 based on Cu2-xSe-Au nanoparticles

In the study, Cu2-xSe-Au nanoparticles (CSA) with a photothermal conversion efficiency of 60.78 % at 808 nm were applied to the construction of thermal analysis immunochromatographic test strips for the highly sensitive quantitative detection of aflatoxin B1 (AFB1) in grain. The CSA was coupled with the AFB1 antibody to form a photothermal sensor probe by physical adsorption. The constructed immunosensor exhibited high sensitivity and a wide linear range from 0.01 to 10 μg/L in PBS. The detection limits of 0.00842 μg/L based on the thermal analysis was significantly improved by 11.88-fold compared with colorimetric results. No cross-reaction with the other mycotoxins was found except for aflatoxin B2, aflatoxin M1, aflatoxin G1 and aflatoxin G2. Applied to analysize grain sample, the method achieved the detection of AFB1 ranging from 0.16 to 160 μg/kg.