Comparison methods of cadmium telluride quantum dot and magnetic silica core shell for detection of aflatoxin B1

The purpose of research is comparison methods of cadmium telluride quantum dot and magnetic silica core shell for detection of aflatoxin B1 based on fluorescence resonance energy transfer (FRET( from cadmium telluride quantum dot to Rho123. Cadmium telluride quantum dot was synthesized by reflux method aquatic phase, high temperature, alkalin pH and under nitrogen flow. The thioglycolic acid is used as a stabilizing and capping agent. After quantum dot synthesis, bougthen anti aflatoxin B1 antibody immobilized on the surface of quantum dot. Subsequently, magnetic silica core shell by using FeCl3 and FeSO4 synthesized under nitrogen flow and alkalin pH and to increase TEOS solution. After preparation aflatoxin B1-albumin bioconjugate is labeled with Rho 123. The specific immune-reaction between the anti-aflatoxin B1 antibody on the quantum dot and the labeled-aflatoxin B1 brings the Rho 123 fluorophore (the acceptor), and the quantum dot (the donor (in close spatial proximity and causes FRET to occur upon photoexcitation of the quantum dot. In the absence of unlabeled aflatoxin B1, the antigen-antibody complex is stable and strong emission of quantum dot observe. In the presence of free aflatoxin B1, it will compete with the labeled aflatoxin B1-albumin complex for binding to the antibody- quantum dot conjugate so that FRET increasingly suppressed. There is a linear relationship between the decreased fluorescence intensity of Rho 123 with increasing concentration of aflatoxin B1 in the range of 0.01-0.06 μmol.mL-1.By using the magnetic silica core shell as a signal intensifier brings sensitivity of the system increased from 2×10-11 to 2×10-12 μmol.mL-1.