화학공학소재연구정보센터
Electrochimica Acta, Vol.43, No.23, 3611-3617, 1998
Rapid methods for detection of Aflatoxin M-1 based on electrochemical transduction by self-assembled metal-supported bilayer lipid membranes (s-BLMs) and on interferences with transduction of DNA hybridization
This work explores the interactions of Aflatoxin M-1 with self-assembled metal-supported bilayer lipid membranes (s-BLMs) and its effects on DNA hybridization. Alterations of electrochemical signals due to DNA hybridization can be used for rapid detection of this toxin. The interactions of Aflatoxin M-1 with s-BLMs composed of egg phosphatidylcholine produced ion current increases which reproducibly appeared within ca. 8-10 s after exposure of the lipid membranes to the toxin when using a stirred solution. The magnitudes of the current signals were related to the toxin concentration, which could be determined within the range of 1.9-20.9 nM. In another series of experiments, Aflatoxin M-1 was found to affect the kinetics and time of signal generation due to DNA hybridization, which was electrochemically monitored by using s-BLMs, The "receptor" oligomer was single stranded deoxyribonucleic acid (ssDNA) thymidylic acid icosanucleotide terminated with a C-16 alkyl chain to assist incorporation into s-BLMs (dT(20)-C-16). The target oligomer was deoxyadenylic acid icosanucleotide (dA(20)) dT(20)-C-16 was incorporated into s-BLMs and complementary dA(20) (cDNA) was injected into the stirred bulk electrolyte solution. The electrochemical ion current across s-BLMs was found to increase due to the presence of ssDNA and decrease due to the formation of double stranded DNA (dsDNA), The toxin reduced the initial rate of signal change and increased the time to reach equilibrium. This provided a means for the rapid (less than 1 min) and sensitive (detection limit 0.5 nM) detection of Aflatoxin M-1 based on measurements of the initial rate of hybridization,