Fluoroimmunoassay Based Quantum Dots For The Determination Of Mycotoxin

Mycotoxin is the inevitable contaminants in the grains of natural,which producedduring the growth of toxin mold.Mycotoxin also can make the immune function andproduction performance of livestock and poultry,make them keep long-term sub-health.In addition,these can cause acute and chronic poisoning of people oranimals,many are also associated with cancer.Mycotoin can enter human body throughthe food chain of meat,eggs and milk.So,preventing,reducing and eliminatingmycotoxin is an important research direction of food safety.Quantum dot is a new type of nanometer materials, which is developing rapidly inrecent years, composed of Ⅱ-Ⅵ andⅢ-Ⅴethnic elements. Quantum dot’s size isgenerally between1-10nm, it can emit fluorescence after stimulated for its confinedelectrons and holes, continuous band structure into discrete energy levels structurewith molecular properties.Compared with the traditional organic fluorescent dyes, ithas the broad excitation spectrum, narrow emission spectrum, precise tuning of theemission wavelength, excellent fluorescent properties such as negligible lightbleaching, which can be well applied to fluorescent labeling.The water-soluble CdTe QDs were synthesized by CdCl2·2.5H2O and Te withMPA as stabilize. through trial and error,it is determined that highest, the strongestfluorescence CdTe quantum dots is prepared under the condition of the precursor ofCdTe quantum dots reacting at room temperature for an hour and a pH of9.2. As thegrowth of the reflux time, the color of the CdTe quantum dots can be graduallychanged from green to pale yellow, yellow, orange red, the red under ultraviolet. Theparticle size was increased with reflux time.The high purity monoclonal against OTA was prepared through cell trawing andthe octylic acid-ammonium sulfate methord.labeling with stable CdTe quantum dotswhich has an emission wavelength of610nm.it preliminary showed that the couplingis succeful through the uv absorption spectrum and fluorescence spectrum. Finally spot test showed us the final success, and antibody still retains the original biologicalactivity.Based the MAb-CdTe QDs conjugates, a novel direct competitive FLISA fordetection of OTA was described. The50%inhibition value (IC50) was0.630ng/mL,and the limit of detection (LOD) was0.0594ng/mL.,the detection linear range was0.091-3.184ng/mL.Using the same methord for the preparation of secondary antibody-CdTe QDs conjugates, the indirect competitive dcFLISA for detection of OTA wasdescribed. The50%inhibition value (IC50) was0.217ng/mL, and the limit of detection(LOD) was0.0172ng/mL, the detection linear range was0.0140~2.753ng/mL. Usingthe MAb-CdTe QDs conjugates, a fluorescence immune chromatography test paperwas established. The detection limit of strip is5ng/mL, the test resoult is validated inthe concentration of0~100000ng/mL.At last, we compared these three kinds of fluorescence immunoassay technology,the FLISA technology has the higher sensitivity than article fluorescence immunechromatography test paper, but strips are more convenient than them.And the detectionlimit of fluorescent immune chromatography test paper is completely can meet thenational standard requirement for OTA residues in food and feed.