Abstract: Devices and methods for gravimetric sensing are disclosed. A gravimetric sensor includes a piezoelectric resonator and an encapsulating layer formed on the surface of the resonator. The encapsulating layer defines a channel within the encapsulating layer on the surface of the resonator. The sensor is fabricated by forming a piezoelectric resonator, forming a sacrificial layer on a surface of the piezoelectric resonator, forming an encapsulating layer over the sacrificial layer on the resonator, and etching the sacrificial layer to remove the sacrificial layer and form a channel on the surface of the resonator. The sensor is used by supplying the liquid to the channel of the gravimetric sensor, operating the piezoelectric resonator, detecting a change in a resonant frequency of the resonator, and determining a presence of the analyte in the liquid from the change in resonant frequency of the resonator.

Abstract: Devices and methods for gravimetric sensing are disclosed. A gravimetric sensor includes a piezoelectric resonator and an encapsulating layer formed on the surface of the resonator. The encapsulating layer defines a channel within the encapsulating layer on the surface of the resonator. The sensor is fabricated by forming a piezoelectric resonator, forming a sacrificial layer on a surface of the piezoelectric resonator, forming an encapsulating layer over the sacrificial layer on the resonator, and etching the sacrificial layer to remove the sacrificial layer and form a channel on the surface of the resonator. The sensor is used by supplying the liquid to the channel of the gravimetric sensor, operating the piezoelectric resonator, detecting a change in a resonant frequency of the resonator, and determining a presence of the analyte in the liquid from the change in resonant frequency of the resonator.

Abstract: Systems and methods for detecting a gaseous analyte utilize a micromechanical piezoelectric resonator having a functionalization layer configured to bind with the gaseous analyte. The functionalization layer may include a layer of carbon nanotubes affixed to the resonator and coated with biopolymers configured to bind with the gaseous analyte. The gaseous analyte may be detected by operating the micromechanical piezoelectric resonator and functionalization layer in the presence of the gas, detecting a change in the resonant frequency of the resonator, and determining the concentration of the gaseous analyte from the change in resonant frequency. Finally, the layer of carbon nanotubes may be grown on the piezoelectric resonator by depositing a catalyst on a piezoelectric structure, heating the piezoelectric structure and the catalyst to enhance the growth of the carbon nanotubes, and growing the carbon nanotubes at growth sites on the piezoelectric structure.