Development of Au nanocluster-based fluorescent strip immunosensor for sensitive detection of aflatoxin B.

Gold clusters with intriguing chemical/physical properties have great promise in applications such as sensing and bio-imaging due to their fascinating photoluminescence character. In this study, an immunofluorescence sensor based on levonorgestrel protected atomically precise Au nanocluster (AuNC) for aflatoxin B (AFB) detection was fabricated due to its strong carcinogenic and mutagenic effect on humans. The prepared polymer-AuNC nanospheres displayed bright luminescence and good stability in aqueous solution. The obtained AFB fluorescent strip immunosensor achieved quantitative point-of-care detection of AFB in less than 15 min, with high selectivity and detection limits down to 0.27 ng/mL. In addition, the recovery rates of AFB from tea soup ranged from 96% to 105% with relative standard deviations less than 10%. This work not only realized high-sensitively fluorescent sensing for AFB, but also expanded the bio-applications of atomic-precise metal clusters.