Detection Of Mycotoxin In Peanut Oil Using Fluorescence Probe Based On Upconversion Nanoparticles(UCNPs)

In peanut oil, mycotoxin is an important indicator for the food safety that attracts the attention of the majority of people and government. Therefore, study of the simple, efficient and sensitive method for mycotoxin detection in peanut oil is an emergency requirement. Along with the development of nanotechnology and biotechnology, nanomaterials were brought into the field of biosensors to improve the accuracy and stability of the test sample results. Because of the unique optical properties of upconversion nanoparticles(UCNPs), there is wide application prospect in the field of biosensing detection. Based on this, our study provides a simple, highly efficient and sensitive fluorescence nanoprobe to achieve rapid detection of mycotoxins in peanut oil by using immunological and rare earth element doping synthesis method, which synthesized UCNPs with independent light emitting characteristics. The specific contents are as follows:1. Synthesis of UCNPs for building the fluorescence nanoprobe. With yttrium chloride, chloride ytterbium, Erbium Chloride, holmium chloride, thulium chloride as raw materials, 100 nm particle sized pure crystal type of UCNPs with high fluorescence yield and good dispersion was synthesized by using rare earth elements doped high temperature thermal decomposition method. Transmission electron microscopy and X-ray diffraction were used to test the UCNPs’ characters. The rare earth elements concentration, experimental time and temperature were optimized to improve the heterogeneous and larger particle size, weak fluorescence intensity characters of UCNPs. Aqueous-favoring UCNPs was successfully obtained with the surface amino modification for the next mycotoxin detection applications.2. Quantifying Aflatoxin B1 in peanut oil using fabricated fluorescence probes based on upconversion nanoparticles(aflatoxin(AFB1) as research object). Based on established method in part 1, oil phase UCNPs(OA-UCNPs) with excellent properties was prepared firstly. By using surface amino modification and connecting artificial antibody, UCNPs became as a fluorescence signal. Magnetic nanoparticles(MNPs) was connected with corresponding antigen. With specific immune function, UCNPs and MNPs form the immune complexes. Using magnetic separation and enrichment function, supernatant with UCNPs was obtained. Under the 980 nm near-infrared laser excitation, a group of fluorescence emission was achieved to present the different concentration of AFB1. As the research object, the fluorescence emission intensity is inversely proportional to the concentration of AFB1. With the UCNPs fluorescence label, antigen and antibody specific recognition and magnetic separation, the successful detection of AFB1 was done with detection limit of 0.1 ng?ml-1.3. Designing ultrasensitive fluorescence probe using the modified UCNPs for simultaneously sensing double mycotoxins in peanut oil(AFB1 and deoxynivalenol(DON) as the research objects). Based on established method in part 1, two kinds of oil phase UCNPs with excellent properties were prepared firstly. By using surface amino modification and connecting artificial antibody, two kinds of UCNPs with no overlap fluorescence spectrum become as the fluorescence signal. MNPs were connected with corresponding antigens. With specific immune function, UCNPs and MNPs formed the immune complexes. Using magnetic separation and enrichment function, supernatant with UCNPs was obtained. Under the 980 nm near-infrared laser excitation, two groups of fluorescence emissions were achieved to present the different concentration of AFB1 and DON. As the research object, the fluorescence emissions intensity is inversely proportional to the concentration of AFB1 and DON. With the UCNPs fluorescence label, antigen and antibody specific recognition and magnetic separation, the successful detection of AFB1 and DON were obtained with detection limit of 0.001 ng?ml-1.