Development of a quartz crystal microbalance (QCM) immunosensor for the detection of Listeria monocytogenes

This study presents the development of a QCM immunosensor for the detection of Listeria monocytogenes. A self-assembled monolayer (SAM) of thiosalicyl ic acid is incorporated for the covalent attachment of antibodies to the go ld surface of the piezoelectric crystal. A non-Sauerbrey increase in freque ncy is observed upon exposure of such a crystal to specific antigen cells. This unexpected response is consistent with the obtained results and is sho wn to be specific. The sensor can detect L. monocytogenes cells in real tim e in solution to 1 x 10(7) cells/ml. The sensor is reusable more than 10 ti mes without detectable loss in activity and shows negligible response to a non-specific pathogen, Bacillus cereus. The lifetime of the thiolated cryst al was also investigated. (C) 2001 Elsevier Science Inc. All rights reserve d.