Development of Au8 nanocluster-based fluorescent strip immunosensor for sensitive detection of aflatoxin B1

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 Au8 nanocluster (Au8NC) for aflatoxin B1 (AFB1) detection was fabricated due to its strong carcinogenic and mutagenic effect on humans. The prepared polymer-Au8NC nanospheres displayed bright luminescence and good stability in aqueous solution. The obtained AFB1 fluorescent strip immunosensor achieved quantitative point-of-care detection of AFB1 in less than 15 min, with high selectivity and detection limits down to 0.27 ng/mL. In addition, the recovery rates of AFB1 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 AFB1, but also expanded the bio-applications of atomic-precise metal clusters.