Piezoelectric biochips having fluidic channels

A method for characterizing presence of a first analyte in a liquid using a biochip having one or more biosensors, the biochip comprising:

• a piezoelectric substrate having a substrate top surface and a substrate bottom surface and comprising, for at least a first biosensor, (i) a top fluidic channel formed in the substrate top surface and traversing from a top fluidic inlet to a top fluidic outlet and (ii) a bottom well formed in the substrate bottom surface and located below the top fluidic channel between the top fluidic inlet and the top fluidic outlet;
• a top electrode formed within the top fluidic channel on the substrate top surface and located above the bottom well;
• a top electrical trace formed on the substrate top surface and traversing from a top-electrode tap to the top electrode;
• a bottom electrode formed within the bottom well on the substrate bottom surface and located below the top electrode;
• and
• a bottom electrical trace formed on the substrate bottom surface and traversing from a bottom-electrode tap to the bottom electrode, wherein the top and bottom electrodes and the intervening piezoelectric substrate form the first biosensor, the method comprising:
• (a) applying the liquid to the top fluidic inlet of the top fluidic channel of the first biosensor such that the liquid flows along the top fluidic channel to the top electrode of the first biosensor;
• (b) applying an alternating electrical signal across the top-electrode and bottom-electrode taps associated with the first biosensor;
• (c) characterizing a vibration frequency of the first biosensor resulting from applying the alternating electrical signal;
• and
• (d) characterizing the presence of the first analyte in the liquid based on the vibration frequency of the first biosensor.