DETECTION OF OCHRATOXIN A BASED ON A NEW APTAMER SENSOR

Ochratoxin A (OTA) is secondary metabolite produced by filamentous fungi of Aspergillus and Penicillium,and it is widely distributed and has become a common food borne contaminant.Ochratoxin A (OTA) has liver toxicity,nephrotoxicity and carcinogenic teratogenic effects,and has huge threat to the human health.Therefore,it is very important to find a sensitive and rapid OTA detection method for ensuring food safety.In this paper,a Th/cPC-AuNPs-cDNA/Apt/AuE sensor for rapid detection of OTA was prepared by using thionine (Th) as electrochemical probe based on aptamer and cPC-AuNPs;and the Th/cPC-AuNPs-cDNA/Apt/AuE sensor possessed the advantages of electrochemical method such as simple equipment,portability,low cost,and quick response,the superiorities of aptamer such as high affinity,high stability and easy modification of functional groups,as well as the characteristics of carboxylated porous carbons such as large specific area.The results of electrochemical impedance spectroscopy showed that the aptamer wassuccessfully immobilized on AuE and combined with cDNA.The experimental parameters were optimized as follows:the optimum incubation time of aptamer was 1.5 h,the optimum concentration of aptamer was 5 μmoL/L,the optimum hybridization time between aptamer and cDNA was 2 h,and the optimum amount of cDNA was 9 μL.Under the optimal conditions,the standard curve was established,which had good linear relationship within 10^-6 μg/mL to 10^-2 μg/mL,and the detection limit of OTA was 10^-6 μg/mL.The mehtod is easy to operate,economic,fast,and is suitable for filed detection.