Enrichment,Purification And Detection Of OTA Based On The Magnetic Photonic Crystal Microsphere

Mycotoxins are common pollutants in cereals and cereal products,causing serious threat to human health.At present,many methods have been developed for the purification and detection mycotoxins,but they have many disadvantages,such as high cost,long detection time and complex operation.Therefore,it is very important to develop a new,fast,low-cost,high sensitivity method to enrich?purify and detect mycotoxins.We used Stober method to synthesize monodisperse nano-silica microspheres.Magnetic nano particles were added in the mixtures to get magnetic nano silica microsphere emulsion.We used a lab-made simple micro-fluidic device to produce magnetic photonic crystal microspheres.By changing the proportion of ammonia water,water and TEOS,we got the different particle size of nano silica microspheres.The magnetic photonic crystal microspheres with different colors and different reflection peaks could be prepared by self-assembly.The magnetic photonic crystal microspheres with different magnetic intensity could be obtained by changing the proportion of magnetic particles.With the increase in the proportion of magnetic particles,the structure of magnetic photonic crystal microspheres will be changed.We choose Fe3O4:TEOS(mg/mL)=3.3 as the best experimental conditions.Based on the high specificity,high affinity of aptamer and the magnetic property of magnetic photonic crystal microspheres,an enrichment and purification method for OTA was developed.The results of preliminary experiments showed that the efficiency of enrichment and elution was poor.We seek for the reason and selected the best experimental conditions.The optimal conditions are as follows:carboxyl group as the functional modification group on the surface of microspheres,the mixed liquid(50%acetonitrile + 50%methanol)as elution solution,6000nmol/L as the concentration of aptamer.When the number of microspheres is 500,the recovery is 56.33%.Based on aptamer recognition technology and liquid phase chip technology,a detection method for OTA using magnetic photonic crystal microspheres was established.The optimization of reaction conditions are as follows:carboxyl group is used as the functional modification group on the surface of microspheres;the concentration of OTA-aptamer was 1000nmol/L;the concentration ratio of the OTA-aptamer and complementary strand was 1:3.Under the optimization conditions,the linear range for the OTA concentration detection was 0.0001-10ng/mL and the linear equation was y=5883.75+1649.33x,R2=0.9915.