Selective and Sensitive Electrochemical Sensor for Aflatoxin M1 with a Molybdenum Disulfide Quantum Dot/Metal-Organic Framework Nanocomposite

Aflatoxins are the hepatotoxic secondary metabolites which are highly carcinogenic and known to cause several adverse effects on human health. The present study reports a simple, sensitive, and novel electrochemical sensor for aflatoxin M1 (AFM1). The sensor has been fabricated by modifying the screen-printed carbon electrodes with a functional nano-composite of molybdenum disulfide (MoS2) quantum dots (QDs) and a zirconium-based metal-organic framework (MOF), that is, UiO-66-NH2. The MoS2/UiO-66-modified electrodes were decorated with the AFM1-specific monoclonal antibodies and then investigated for the electrochemical detection of AFM1. Based on the electrochemical impedance spectroscopy analysis, it was possible to detect AFM1 in the concentration range of 0.2-10 ng mL(-1) with a limit of detection of 0.06 ng mL(-1). The realization of an excellent sensing performance can be attributed to the electroactivity of MoS2 QDs and the large surface to volume area achieved by the addition of the MOF. The presence of UiO-66-NH2 is also useful to attain readily available amine functionality for the robust interfacing of antibodies. The performance of the developed sensor has also been validated by detecting AFM1 in the spiked milk samples.