A highly sensitive photothermal immunochromatographic sensor for detection of aflatoxin B₁ based on Cu_2-xSe-Au...

In the study, Cu_2-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.