Report from the 1st MYCOKEY international conference Global Mycotoxin Reduction in the Food and Feed Chain held in Ghent, Belgium, 11-14 September 2017
Aflatoxins are cancer-promoting natural toxins that are produced by the fungus Aspergillus flavus and Aspergillus parasiticus. Aflatoxins have been regarded as one of the most fatal threat in food safety, due to their strong hepatotoxic, carcinogenic and teratogenic effects on human beings and animals. Among them, aflatoxin B1 (AFB1) is one of the common types which have received considerable attention. Thus, developing a rapid, simple and reliable method for determination of AFB1 in foods is very important. Herein, a preliminary study of Frster resonance energy transfer (FRET) immunoassay based on the cadmium-free quantum dots for determination of AFB1 was described. To avoid the use of hazardous heavy metals, core/shell InP/ZnS quantum dots (QDs) as an alternative for Cd-based QDs were synthesized. A silica shell with epoxy groups was used for water solubilization of the obtained nanoparticles. Then a specific anti-AFB1 monoclonal antibody (mAb) was labelled with the hydrophilic QDs via these highly reactive epoxy groups. Gel electrophoresis was used to control the binding. After that, the FRET system was developed using the Cd-free QDs conjugate as donor. Graphene oxide was selected as acceptor. In order to keep the distance between donor and acceptor close enough, the size of silica coated QDs should be controlled strictly. We found that 1-dodecantiol which was used for ligands change on the surface of InP/ZnS QDs was better than oleylamine and the optimum amount of tetraoxysilane was 5 mu L in the silylanization. Besides, only ethanol and hexane were used to wash silica coated QDs which could ensure good dispersion of QDs in water. The cut-off value for the determination of AFB1 in tube was 10 ng/mL with a preliminary study. Compared to reported FRET assays with Cd-based QDs, the developed FRET was easy-to-operate, visual and safe
