Highly luminescent quantum dot beads(QBs)were synthesized by encapsulating CdSe/ZnS and used for the first time as immunochromatographic assay(ICA)signal amplification probe for ultrasensitive detection of aflatoxin B1(AFB1)in maize.The challenges to use high brightness QBs as probes for ICA are smooth flow of QBs and non-specific binding on nitrocellulose(NC)which is overcome by unique polymer encapsulation of QDs and surface blocking method.Under optimal conditions,the QB-based ICA(QB-ICA)sensor exhibited dynamic linear detection of AFB1 in maize extract from 5 pg mL-1 to 60 pg mL-1,with a median inhibitory concentration(IC50)of 13.87 ± 0.16 pg mL-1,that is significantly 39 folds higher than those of the QD as a signal probe.The limit of detection(LOD)for AFB1 using QB-ICA sensor was 0.42 pg mL-1 in maize extract which is approximate two orders of magnitude better than those of previously reported gold nanoparticles based immunochromatographic assay(AuNP-ICA)and is even comparable or better than the conventional enzyme-linked immunosorbent assay(ELISA)method.The performance and practicability of our QB-ICA sensor were validated with a commercial ELISA kit and further confirmed with liquid chromatography tandem mass spectrometry(LC-MS/MS).Given its efficient signal amplification performance,the proposed QBs-ICA offers great potential for rapid,sensitive,and cost-effective quantitative detection of analytes in food safety monitoring.