Star shaped zinc sulphide quantum dots self-assembled monolayers: Preparation and applications in food toxin detection

We report the results of studies relating to the fabrication of an electrochemical immunosensor based on self-assembled of star shaped thioglycolic acid capped zinc sulphide quantum dots (ZnS QDs) synthesized by hot injection method. Structural and morphological investigations of ZnS QDs have been accomplished via transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), UV-visible spectroscopy (UV-vis) and Photoluminescence spectroscopic (PL) techniques. Further, monoclonal aflatoxin-B1 antibodies (anti-AFB1) have been covalently immobilized onto the ZnS/APTES/ITO electrode surface for the detection of aflatoxin-B1, a potential food toxin using electrochemical impedance spectroscopy. The impedemetric response of the proposed immunosensor shows high sensitivity (176.58 Ω/(ng/mL)/cm2), improved detection limit (0.02 ng/mL) and wide detection range (0.25-2.0 ng/mL). The ZnS QDs based platform provides an efficient platform for the fabrication of immunosensor for the detection of aflatoxin- B1 and these results have implications in the design of highly efficient biosensors for other potential toxins.