Development of electrochemical immunosensor for the detection of aflatoxin M1

Aflatoxin M1 (AFM-1) is a mycotoxin which is a consequence of the metabolism by the cow of aflatoxin B1 that is commonly produced by the fungal strains. Therefore milk and milk products may be contain aflatoxin M1. Aflatoxin M1 has been reported as Group 1 carcinogen by the International Cancer Research Institute (IARC). Therefore, the determination of AFM1 is important. The aim of the project is to develop an immunosensor for the rapid and precise determination of aflatoxin M1. In the designed immunosensor, an AFM1-specific antibody molecule was covalently bound to the disposable screen-printed carbon electrode surface. It was then treated with AFM1 to bind. This antibody / aflatoxin complex formed on the surface was determined by electrochemical impedance spectrometry technique (EIS). Ochratoxin A (OTA) toxin that does not interact with anti– AFM1 was used to determine the selectivity of the designed immunosensor. Thus, an unmarked rapid recognition system without any marking has been developed. In order not to bind a foreign molecule or structure to the surface, blockage studies, blockage studies were performed with BSA and the responses of BSA coated and uncoated surfaces were evaluated. In this study, the most suitable antibody concentration was determined as 0.2 ppm by using disposable screen printed electrodes. When the obtained spectrometry data were evaluated, it was observed that the increase in toxin concentration increased the answers but the most appropriate separation was obtained with 0.1 ppm toxin concentration. According to the results, the limit of determination (LOD) was calculated as 0.3 ppb. Gold nanoparticles (AuNP) modified and unmodified sensor surfaces were studied with different mk samples. When the analysis data were examined, it was found that the response of AuNP modified surface was higher and the sensitivity increased considerably. It was concluded tahat the biosensor system designed according to these results may be the basis for the analysis of other toxins threatening food safety.