Studies On The Label Free Detection For OTA And FB₁ In Agriculture Products Based On Aptamer-Porous Silicon Sensing Chip

Mycotoxins are one of the main pollutants in agricultural products and feed,and they are teratogenic,carcinogenic,mutagenic toxicity to human and animal.However,the traditional detection methods are costly,complex and professional.It is of important significance to develop a simple,rapid,economic,high sensitivity detection method.Porous silicon has many excellent characteristics and is very suitable for biosensor.Aptamer is a new recognition molecule,and it is promising in the field of rapid detection of mycotoxins.In the paper,we have developed a label free biosensor chip used to rapidly detect OTA and FB1 in agricultural products,with porous silicon as the sensing substrate and aptamer as the recognition molecule.The main contents are as follows:(1)Porous silicon was prepared by electrochemical etching in the paper.In order to enhance the stability of the porous silicon,TiO2 nano layer was spin-coated on its surface.SEM and the reflection interference spectrum graph display TiO2 was evenly covered on the surface of the porous layer,and the porous structure of the original was well preserved.At the same time,the surface modification of TiO2 was studied.The results showed the chip modified by the aldehyde group was better than the one modified by the epoxy group.(2)Through the optimization of the experimental conditions of the system,The paper developed a label free biosensor aptamer-porous silicon biosensor used to detect OTA and FB1.The standard curves of OTA and FB1 are established respectively by Fourier transformed reflectometric interference spectroscopy(FTRIFS).The linear regression equations were y=0.20526x-0.06639(R2=0.97331)and y=0.29912x-0.08663(R2=0.97699),the linear range were 1?100ng/mL and 0.1?100ng/mL,the lowest detection limits were 0.5ng/mL and 0.05ng/mL.The recovery rate of rice,corn and wheat were determined.The recovery rate of OTA and FB1 were 68.06±5.48%?90.51 ±8.36%and 66.18±6.02%?91.58 ± 7.34%.The comparison with ELISA displayed the results of the two methods were consistent.(3)A aptamer-porous silicon 2×2 array was prepared in the paper.OTA and FB1 aptamers were modified in different sensing sites of the porous silicon array.Multiple detection of OTA and FB1 was performed by Fourier transformed reflectometric interference spectroscopy(FTRIFS).The multiple detection standard curves of OTA and FB1 were established respectively.The linear regression equations were y=0.18566x-0.08244(R2=0.98552)and y=0.2813x-0.01072(R2=0.97336),the linear range were 10?100ng/mL and 5?100ng/mL,the lowest detection limits were 5ng/mL and 1ng/mL.The multiple recovery rate of rice,corn and wheat were determined.The multiple recovery rate of OTA and FB1 were 65.43 ±6.08%?87.76±7.29%and 64.85 ±6.08%?88.57±6.98%.