Chemiluminescence Detection For Mycotoxins In Agriculture Productions Based On Photonic Crystal Microsphere Suspension Array

The safety of agricultural products has always been the one of focus attentions in many countries and regions. Among them, mycotoxin contamination accounted for a large proportion. There are a variety of methods to detect mycotoxins, but they are complicated to operate, need large of reagents, detection time, and high cost. In this paper, we use a new nanomaterial-photonic crystal as a carrier, and chemiluminescence-based immunoassay techniques, in order to establish a high throughput, low cost, and can simultaneously detect multiplex mycotoxin detection system.We use Stober method to synthesize monodisperse nano-silica microspheres and use these microspheres to assemble photonic crystal microspheres, by calcination to increase their mechanical strength and hydrophily. Fiber optic spectroscopy and scanning electron microscopy are used to characterize the microspheres. Chemically modifying the surface of the microspheres is used to enhance the binding capacity of the biological macromolecules.The photonic crystal microspheres have large surface area and can effectively increase the number of binding biological molecules, thereby improving the detection sensitivity. Aflatoxin B1 in agricultural products was detected, through optimization of the reaction conditions, which was pH=9.6 carbonate buffer as coating buffer,1200 ng/mL of coating AFB1-BSA antigen concentration,1:10000 dilution of aflatoxin B1 monoclonal antibody, 1:6000 dilution of horseradish peroxidase-labeled secondary antibody (HRP-IgG). Under the optimized conditions for aflatoxin B1, curve linear range was 1-0.0001 ng/mL, the linear equation was y=2663.676-4176.177x, R2=0.99546. The specific experiment showed that there was no significant cross-reactivity with aflatoxin B1 analogues. The recoveries determination from different concentrations of aflatoxin B1 in agricultural products was performed, which were:82.86±3.66%-112.82±3.33% in rice,78.69±6.72%-116.52± 10.23% in corn,75.88±15.86%-122.92±10.49% wheat, respectively.The optical properties of photonic crystal microspheres were measured by fiber optic spectrometers. The reflection peak positions of microspheres were used for optical encoder carriers. The microspheres were coated by three antigens (AFB1-BSA, FB1-BSA, OTA-BSA), The conditions of the reaction Multiplex mycotoxin detection in agricultural products were optimized with reference to the single detection of the reaction conditions. The simultaneous detection for three mycotoxins (AFB1,FB1, OTA) based on photonic crystal microspheres carrier suspension array was established. The linear range is 1-0.001ng/mL for AFB1 and FB1,1-0.01 ng/mL for OTA, Linear equations is y=3998.538-3509.456x (R2=0.98667), y=2184.189-3493.776x (R2=0.99666) and y=1930.813-1504.993x (R2=0.99112) respectively for AFB1,FB1 and OTA. Finally, recoveries were 88.41±9.00%-124.66±8.54% for AFB1,72.07±7.12%-123.78±7.97% for FB1,77.77±3.25%-114.36±13.17% for OTA in rice.