Hyperbranched Gold Plasmonic Blackbodies Enhanced Immunochromatographic Test Strip for the Sensitive Detection of Aflatoxin B1 in Maize Sample

In this work, we synthesized a novel hyperbranched Au plasmonic blackbody (AuPB) and applied it as a signal amplification label in immunochromatographic test strip (ICTS) sensor for the sensitive detection of aflatoxin B-1 (AFB(1)) in maize. AuPB were characterized with high color signal intensity, superior colloidal stability, and excellent biocompatibility benefiting from the hyperbranched structure and the dense polydopamine layer on surface, which contributes to improving the sensitivity and robustness of competitive ICTS sensor. Under the optimized conditions, the half inhibition concentration and the detection limit of our AuPB-enhanced ICTS (AuPB-ICTS) sensor were 0.087 and 0.016 ng/mL, which are 3.9- and 5.4-fold lower than those of traditional ICTS sensor based on 35-nm gold nanospheres as signal reporters. The average recoveries for the intra- and inter-assay ranged from 92.5 to 119.5%, with the coefficient of variation of 3.29-10.28%. Moreover, the reliability and practicability of this method were validated by the well-established ultra-performance liquid chromatography method via simultaneously measuring fifteen naturally contaminated maize samples. In summary, the developed AuPB-ICTS sensor can serve as an alternative rapid diagnostic method to allow the sensitive and reliable screening of AFB(1) in maize.