Preparation of 3D pomegranate‐like quantum dot nanobeads and its application to highly sensitive detection of aflatoxin B1

Abstract

Aflatoxin B1 (AFB1) is often used as a major indicator for evaluating aflatoxin contamination in food, and its accurate and sensitive detection is of great significance. Herein, the high-quality CdSe/ZnS fluorescent quantum dot nanobeads (QBs) with 3D pomegranate were prepared by the dual-protecting microemulsion method, which showed excellent stability in different environments. AFB1 were detected by competitive quantum dot-based fluorescence-linked immunosorbent assay (QLISA) using 3D pomegranate-like QBs and single-core silica-encapsulated quantum dots (QD@SiO2). After optimization of the reaction conditions, the quantitative detection range of AFB1 by single-core QD@SiO2 as fluorescent probe was 0–100 ng/mL, with the half maximal inhibitory concentration (IC50) of 3.01 ng/mL and the limit of detection (LOD) of 0.12 ng/mL; whereas the quantitative detection range of AFB1 by fluorescent QBs was 0–100 ng/mL, with the IC50 of 1.76 ng/mL and the LOD of 1.03 pg/mL. Compared to single-core QD@SiO2, the fluorescent QBs was 120-fold more sensitive. The detection of AFB1 was also achieved in negative corn and peanut samples, indicating the possibility of its application to the detection of real food samples. The high performance of competitive QLISA using 3D pomegranate-like QBs as fluorescent probes offer highly sensitive and accurate quantitative detection of analytes in food safety monitoring.