Patent ID: 7651843

Claim:
A method of detecting and identifying bacteria, micro-organisms or plants in a liquid or gaseous medium, said bacteria, micro-organisms or plants being of the kind which produce autoinducer signaling molecules in intercellular space, said method including positioning an acoustic wave biosensor in the liquid or gaseous medium, said acoustic wave biosensor comprising a plurality of spaced apart electrodes disposed on a substrate of piezoelectric material and having a biolayer matched to a specific type of autoinducer signaling molecule to be detected, the biolayer comprising a layer of heterobifunctional molecules comprising protein A disposed on the electrodes and on the piezoelectric material between the electrodes, a plurality of bioreceptor molecules which bind exclusively with the specific type of autoinducer signaling molecule to be detected, the bioreceptor molecules being supported by the layer of heterobifunctional molecules, and a hydrogel layer surrounding the bioreceptor molecules to support a three-dimensional structure thereof so that the bioreceptor molecules can bind with the specific type of autoinducer signaling molecule to be detected, whereby the biolayer is reactive to the specific type of autoinducer signaling molecule to be detected such that corresponding autoinducer signaling molecules bind to the biolayer so as to vary acoustic characteristics of the acoustic wave biosensor, and detecting such variation of the acoustic characteristics of the acoustic wave biosensor and thereby determining the presence of the bacteria, micro-organisms or plants in the liquid or gaseous medium.