Electrochemical transduction of interactions of aflatoxin M-1 with bilayer lipid membranes (BLMs) for the construction of one-shot sensors

This work explores the transduction of interactions of aflatoxin M-1 with bilayer lipid membranes (BLMs) composed from egg phosphatidylcholine (PC) that can be used for the direct electrochemical sensing of this toxin for the construction of one-shot devices. The interactions of aflatoxin Mi with these Langmuir-Blodgett films 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 a after exposure of the membranes to aflatoxin. The mechanism of signal generation was associated to the alterations of the electrostatic fields at the surface of membranes due to aflatoxin aggregation at BLMs, thereby providing a transient charging current which lasted for a period of the order of seconds. The magnitude of the transient current signal was related to the concentration of aflatoxin M, in bulk solution in the range 2-15 nM. The present preliminary work includes novel applications of BLM-based films in real samples and examines the matrix effects in the electrochemical transduction for the determination of aflatoxin M, in skimmed milk. (C) 1997 Elsevier Science S.A.