Aptamers-Porous Silicon Biochip Detection For Multiplex Mycotoxins In Cereal Samples

Mycotoxins are highly toxic and common pollutants in grains, which make grains moldy, product quality declines and have teratogenic, carcinogenic, mutagenic effect on human and animals. At present, there are many methods to detect mycotoxins, but there have many shortcomings, such as: expensive equipment,cumbersome steps, high detection costs, and the low sensitivity of trace toxin residue detection. Porous silicon has a large specific surface area and more binding sites.When porous silicon was used in the detection of toxins, it can detect trace toxic toxins, moreover the price of porous silicon is relatively cheap and the operation is relatively simple. Therefore, based on the application of porous silicon-aptamers, the chip scanner establishes a method for the detection of mycotoxins in cereals.In this paper , the P-type single crystal silicon was used as the material to prepare porous silicon through the electrochemical etching method. In order toincrease the stability of porous silicon, porous silicon surface spin was coated with a layer of TiO2.The porous silicon surface modified epoxy groups covalently bind to the hybrid between the aptamer which modified with a fluorescent group and the strand of complementary which modified with the fluorescent quenching group. When the toxin passes, aptamers will bind to the toxin and separate with the complementary strand , the fluorescence value will increase. OTA, AFB1 and FB1 can be detected by measuring the fluorescence addition value after adding toxins.The porous silicon surface modified epoxy groups covalently bind to the nucleic acid aptamers to detect ochratoxin A (OTA), aflatoxin B1 (AFB1) and fumonisins B1 (FB1) . This paper established method is applied to optimize the reaction conditions, respectively established three toxin detection standard curve,the linear range of OTA was 0.01?10ng / mL, the detection line was 0.01ng / mL, the linear equation: y = (R2 = 0.9935);the linear range of detection of AFB1 was 0.001 ?1ng / mL,the detection line was 0.001ng / mL, the linear equation: y = 339.8828x + 1888.4533 (R2 = 0. 0.9960); The linear range of FB1 was 0.01 ? lOng / mL, the calibration curve was O.Olng / mL, and the linear equation: y = 595.8202x + 2772.2389 (R2 = 0.9899). For example, when OTA was detected, the recovery rate of this method is: 92.69 ± 3.26% ?101.80 ± 2.80%in wheats,86.06 ± 1.29% ?100.66 ± 1.44% in rice, 85.74 ± 2.75% ?99.92 ± 1,63%in corns. The overall recovery rate is from 80% to 110%, indicating that this method is functional when testing the recovery rate in different grains.On the basis of single component detection of OTA, AFB, and FB1, a method for quantitative detection of these three toxins was established according to the optimal reaction conditions. The detection line of OTA was 0.1 ng / mL, the detection line of AFB1 was 0.01 ng / mL,and the detection line of FB1 was 0.001 ng / mL.When compared to the recovery rate of ELISA, these two results are correlation,indicating that the method established in this paper is feasible.