An acoustic wave biosensor comprises 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 comprises a layer of heterobifunctional molecules disposed on the electrodes and on the piezoelectric material between the electrodes, and a plurality of bioreceptor molecules which bind exclusively with the specific type of autoinducer signaling molecule to be detected. The bioreceptor molecules are supported by the layer of heterobifunctional molecules, and a hydrogel layer surrounds the bioreceptor molecules to support a three-dimensional structure thereof. The bioreceptor molecules can bind with the specific type of autoinducer signaling molecule to be detected, and the biolayer is reactive thereto such that corresponding autoinducer signaling molecules bind to the biolayer and detectably vary acoustic characteristics of the acoustic wave biosensor.