Layer-by-layer assembled smectite-polymer nanocomposite film for rapid fluorometric detection of aflatoxin B1

Aflatoxin B1 (AFB1) is a potent biological toxin produced by fungi Aspergillus flavus and Aspergillus parasiticus. Current quantification methods for AFB1 are mostly established on immunoaffinity columns which are both costly and labor intensive. Inspired by smectites’ high AFB1 adsorption capacity and affinity, we report the synthesis of a smectite-polyacrylamide (PAM) nanocomposite film for AFB1 detection and prove the feasibility of such a film for AFB1 quantification. A layer-by-layer assembly process was developed to achieve uniform morphology and thickness of the nanocomposite films on flat silicon substrates. Positive correlations between the peak fluorescence intensity of the adsorbed AFB1 and its concentration in the test solutions were obtained. The smectite-PAM nanocomposite film has shown similar AFB1 adsorption capabilities as the smectite, while exhibiting excellent structural stability in aqueous solutions. Our results suggest the feasibility of using the smectite-PAM nanocomposite film as a simple biosensor to achieve rapid fluorometric quantification of AFB1.