Development Of New Electrochemical Detection Methods For Ochratoxin A

Ochratoxin A is a toxin metabolite produced by Penicillium and Aspergillus,which widely exits in cereals and other agricultural products.It can damage the human kidney and liver,and cause the mammals produce cancer,kidney poisoning,liver poisoning as well as the harm of immunotoxicity.Therefore,it is important to establish rapid,sensitive and convenient detection methods for ochratoxin A(OTA).This study focused on the development of such methods.On one hand,aptamer was applied to achive rapid detection.On the other hand,suitable sample pretreatment and nano-materials were adopted to improve the sensitivity.The concrete research is as follows:Firstly,the dynamic sensing range of the electrochemical aptasensor is tuned with the application of assistant free aptamer probe in the sensing system by the fabricated electrochemical aptasensor.Extraordinary dynamic sensing range from 10-8 to 100 ppb,which is 11-order magnitude of OTA concentration,is successfully achieved easily.More importantly,the signal response in all concentration ranges is in the same current scale,demonstrating that the sensing protocol in this research can realize the accurate detection of OTA in broad range without using signal amplification treatment.Real spiked samples in different dynamic sensing ranges are determined with the electrochemical aptasensor under the optimized sensing conditions.This dynamic sensing range tuning strategy may offer a promising guidance of electrochemical aptasensor optimizations for further wide applications.Secondly,the rapid and sensitive detection was realized by probe conbined with gold-nanoparticles and different self-assembly of electrode.It used the high specific surface area of gold nanoparticles to enrich the signal molecules to achive signal amplification.And then,the detection width was improved by the assembly of the gold nanoparticles,which was coupled with probes,on the surface of electrode.The detection range of the electrochemical aptasensor is from 0.001 to 1000 ppb,which is broadened by 2 orders of magnitude compared to the base type.And it was suitable for apllying to real samples,and for further wide applications.