Electrochemical investigation of transduction of interactions of aflatoxin M1 with bilayer lipid membranes (BLMs)

This work explores the interactions of aflatoxin M1 (AFM1) with bilayer lipid membranes (BLMs) composed from egg phosphatidylcholine (PC) that can be used for the direct electrochemical sensing of this toxin. The interactions of AFM1 with these membranes were found to be electrochemically transduced by BLMs in the form of a transient current signal with a duration of seconds, which reproducibly appeared within 7 s after exposure of the membranes to aflatoxin. The sensitivity of the response was maximized by the use of BLMs composed of PC. The mechanism of signal generation was electrochemically investigated and associated to alterations of the electrostatic fields at the surface of membranes (i.e., reorganization of membrane electrochemical double layer that results in a charging current signal) due to the adsorption of AFM1. The magnitude of the transient current signal was related to the concentration of aflatoxin M1 in bulk solution in the range 2–15 nM. The potential application of the present electrochemical transduction for the determination of AFM1 in skimmed milk was explored.