Surface acoustic wave hydrogen sensor

The present invention provides a delay line SAW device fabricated on a lithium niobate substrate and coated with a bilayer of nanocrystalline or other nanomaterials such as nanoparticles or nanowires of palladiumn and metal free pthalocyanine which will respond to hydrogen gas in near real time, at low (room) temperature, without being affected by CO, O.sub.2, CH.sub.4 and other gases, in air ambient or controlled ambient, providing sensitivity to low ppm levels

Design of a Portable Orthogonal Surface Acoustic Wave Sensor System for Simultaneous Sensing and Removal of Nonspecifically Bound Proteins

One challenge for current surface acoustic wave (SAW) biosensors is reducing nonspecific adsorption. A device propagating Rayleigh and shear horizontal surface acoustic waves in orthogonal directions fabricated in ST quartz has the capability of achieving simultaneous detection and nonspecific binding (NSB) protein removal. Current measurement methods for a SAW sensor system based on this device require large-size and expensive equipment such as a vector network analyzer (VNA), signal generator, and frequency counter, which are not suitable for portable, especially point-of-care, applications. In this work, a portable platform based on a direct digital synthesizer (DDS) is investigated for the orthogonal SAW sensor, integrating signal synthesis, gain control, phase/amplitude measurement, and data processing in a small, portable electronic system. This prototype was verified for both stability and repeatability, and the results matched very well with VNA measurements. Finally, system performance in real-time sensing and NSB removal was evaluated

Microcavity enhanced surface acoustic wave devices

Shear-horizontal surface acoustic wave sensors with micro-cavities in the delay paths were studied using finite element methods. The microcavity devices are SAW delay path devices that have the delay path etched with square patterns at various wavelength dimensions and varying depths to increase the dispersion and bulk to surface wave conversion. Additionally the microcavities are filed with polystyrene to act as an inhomogeneous waveguide for further entrapment of wave energy near the device surface. The effects of micro-cavities and grooves on SAW propagation show significantly greater energy transmission than the other structures presented traditional sensors

Alloy nanoparticles for metal-enhanced luminescence

Metal enhanced luminescence using alloy nanoparticles offers additional degrees of freedom for tuning their optical properties by altering atomic composition and atomic arrangement when compared to pure metal nanoparticles such as gold and silver. Surface plasmon resonance wavelengths of silver-copper nanoparticles were tuned in the visible and near infrared region by changing annealing temperature. Strong emission enhancement of luminophores at the vicinity of the Ag—Cu nanoparticles was shown when the SPR spectrum was tuned to produce maximum spectral overlap. As the SPR spectrum can be easily tailored, this platform can be effectively used to enhance luminescence of different luminophores

Surface acoustic wave hydrogen sensor

The present invention provides a delay line SAW device fabricated on a lithium niobate substrate and coated with a bilayer of nanocrystalline or other nanomaterials such as nanoparticles or nanowires of palladiumn and metal free pthalocyanine which will respond to hydrogen gas in near real time, at low (room) temperature, without being affected by CO, O2, CH4 and other gases, in air ambient or controlled ambient, providing sensitivity to low ppm levels

High frequency thickness shear mode acoustic wave sensor for gas and organic vapor detection

A thickness shear mode (TSM) sensor having a visco-elastic polymer coating and a fundamental frequency greater than 20 MHz useful for organic vapor or gas detection. The TSM quartz resonators at a fundamental frequency of 96 MHz were evaluated for their performance in organic vapor sensing applications and results were compared with the performance of 10 and 20 MHz resonators. These devices were produced by chemical milling of AT-cut quartz. Seven test organic vapors were utilized at concentrations ranging from 0.2 volume percent to 13.7 volume percent in the vapor phase. In all cases, the rubbery polymer polyisobutylene was used as a sensing layer. Detailed results for various sensor parameters such as sensitivity, baseline noise and drift, limit of detection, response and recovery times, dynamic range, and repeatability for the 96 MHz device were compared with those for 10 and 20 MHz devices. The test case of benzene/polyisobutylene was chosen to make these detailed comparisons. The 96 MHz device was found to be more sensitive than the lower frequency devices. Device sensitivity was dependent on the benzene concentration. Response and recovery times were smaller for the 96 MHz device. Response times decreased with analyte concentration. Sensor response was in reasonable agreement with the perturbation model of Sauerbrey at lower concentrations and deviated at the higher concentrations for the 96 MHz device. Higher frequency TSM devices can be very useful as organic vapor sensors both in detection and process monitoring applications. These devices have the advantages of simpler electronics, easier design and fabrication, well-developed models and good baseline stability when compared to other acoustic wave devices

Method of manufacturing high frequency thickness shear mode gas and organic vapor sensors

A method of fabricating a thickness shear mode (TSM) gas and organic vapor sensor having a visco-elastic polymer coating and a fundamental frequency greater than 20 MHz. The method begins by providing a piezoelectric crystal and milling a central region of the crystal. Milling the crystal creates a central oscillating region of reduced thickness surrounded by a thicker outer region. Two electrodes are then deposited in the oscillating region of the crystal—one on each side of the crystal. The oscillating region on both sides of the crystal and the electrodes are then coated with a polymer coating

Simultaneous sample manipulation and sensing using surface acoustic waves

The present invention provides a hexagonal, delay line surface acoustic wave device fabricated on a a piezoelectric substrate, such as lithium tantalate, coated with an insulating waveguide on to which a sensing film, such as an anti-human Interleukin-6 biosensor film, is physically absorbed. The acoustic waves that propagate along the delay lines of the SAW device provide for detection of biological species along one delay line and simultaneously provide for removal of non-specifically bound protein along the remaining delay lines

Simultaneous sample manipulation and sensing using surface acoustic waves

The present invention provides a hexagonal, delay line surface acoustic wave device fabricated on a a piezoelectric substrate, such as lithium tantalate, coated with an insulating waveguide on to which a sensing film, such as an anti-human Interleukin-6 biosensor film, is physically absorbed. The acoustic waves that propagate along the delay lines of the SAW device provide for detection of biological species along one delay line and simultaneously provide for removal of non-specifically bound protein along the remaining delay lines