A biosensor for detecting the presence of a target compound in a test solution is disclosed. The biosensor includes upper and lower carrier plates, a spacer film with a micro-channel, an inlet port upstream of the micro-channel, an outlet port downstream of the micro-channel, a micro-machined transceiver, and a first molecularly imprinted polymer layer for recognizing and binding the target compound. The micro-machined transceiver includes a micro-machined transmitter for generating an acoustic wave, and micro-machined receiver for generating an acoustic wave-induced voltage. An amplitude of the acoustic wave-induced voltage is varied in response to the concentration of the target compound.