Piezoelectric Detection Research Articles

A New Bacteriophage-Modified Piezoelectric Sensor for Rapid and Specific detection of Mycobacterium

Detection of tuberculosis and related diseases caused by mycobacteria is costly, time-consuming, and labor-intensive. Here a new phage-modified piezoelectric system for rapid and specific detection of mycobacteria was developed. In this system, interdigital gold electrode immobilized with lytic phage was used as a probe in place of a steel electrode in the multi-channel series piezoelectric quartz crystal (MSPQC) system. The probe was directly connected to the piezoelectric detection system. Mycobacterium was specifically captured to the phage-modified electrode and then lysed by immobilized phage, which caused the electrode electrical properties change. This change can be sensitively monitored by the piezoelectric detection system. The detection time of Mycobacterium smegmatis was less than 2 hours and a detection limit of 103cfu mL−1 was obtained. Additionally, it was successfully used to detect Mycobacterium tuberculosis. The developed system using phage-modified interdigital electrode showed high specificity and reproducibility for mycobacterium detection. Compared with the MSPQC system, the proposed system was faster and more specific.

Kornverlusterfassung an Getreidevorreinigern

The piezoelectric grain loss detection has been established for mobile machinery, and is also suitable for process monitoring of grain pre-cleaning. For this purpose, an acceleration sensor measured vibrations of the grain impact of a baffle plate and converted it into an electronic signal which is proportional to the loss. A variety of pre-cleaners, that on the market today, are not electronically controlled or regulated, and a feedback from the loss to the control unit is not provided. The characterization of the sensor system was performed on the new test rig with a grain dose unit. Numerous measurements with different species of crop verify a deviation in the relevant range of less than 3 %.

Rapid screening of poly(ethylene glycol) polymers by C18 column-flow injection with piezoelectric detection system

A rapid and low cost analytical method for the screening and determination of poly(ethylene glycol)s polymers has been developed. Several initial studies were carried out in order to demonstrate the utility of a piezoelectric quartz crystal as a detection system for the quantification of poly(ethylene glycol)s. The method involves the use of a simple flow injection device connected to a piezoelectric quartz crystal detector. Several parameters associated with the simple flow injection manifold were optimized. Subsequently, this detector was coupled to a C18 column and the best experimental conditions were investigated in order to perform the screening and determination of poly(ethylene glycol)s. The applicability of this method, as an analytical screening tool, was demonstrated by the characterization of samples with different molecular mass polymers without using HPLC and CE techniques to carry out oligomer separations. A standard curve to determine the polymer content was obtained by relating the resonance frequency shift and polymer concentration, which showed good linearity and good regression coefficients. The working range, repeatability, limit of detection and recovery were all acceptable for the analysis of the poly(ethylene glycol)s. Finally, the proposed method was applied to determine these polymers in several samples, such as pharmaceutical products, washing powder, detergents and a body spray.

High Sensitive Mass Detection using Piezoelectric Coupled Microcantilevers

Abstract This paper demonstrates the improvement of mass detection sensitivity using a new method of analysis applied to a piezoelectric coupled sensor. First, we prove the performances of an original method of analysis, based on the structures resonance amplitude, which significantly increases the mass detection sensitivity and improves the response time. Second, we show the advantage of coupled microcantilevers with a piezoelectric detection, that leads to a relative voltage variation of 8%/0.1 fg in the range [1 zg, 0.1 fg] versus an interferometric measurement. That opens the door to an ultrasensitive detection of highly diluted analytes in biological fluids.

A New Resonance-Based Method for the Measurement of Nonmagnetic-Conducting-Sheet Thickness

A measurement system to measure the thickness of a nonmagnetic conducting sheet is designed, simulated, developed, and tested. The measurement system is designed as a resonant system with a cantilever being a resonating structure with piezoelectric excitation and detection. The permanent magnets at the tip of the cantilever beams produces an oscillating magnetic field, and the insertion of the conducting sheet in the magnetic field produces eddy current on it. The magnetic field produced due to eddy current alters the magnetic field produced by the permanent magnet. This alters the natural frequency of the measurement system as the stiffness due to the magnetic force varies with thickness. The simulation and experimental results show that the resonant frequency of the measurement system varies linearly with thickness and sensitivity is found to be higher for the material having higher conductivity.

Piezoelectric detection of bilirubin based on bilirubin-imprinted titania film electrode

A novel quartz crystal microbalance (QCM) sensor with a high selectivity and sensitivity has been developed for bilirubin determination, based on the modification of bilirubin-imprinted titania film onto a quartz crystal by molecular imprinting and surface sol-gel techniques. The performance of the developed bilirubin biosensor was evaluated and the results indicated that a sensitive bilirubin biosensor could be fabricated. The obtained bilirubin biosensor presents high-selectivity monitoring of bilirubin, better reproducibility, shorter response time (30 min), wider linear range (0.1–50 μM), and lower detection limit (0.05 μM). The analytical application of the bilirubin biosensor confirms the feasibility of bilirubin determination in serum sample.

Photoacoustic section imaging with an integrating cylindrical detector

A piezoelectric detector with a cylindrical shape is investigated for photoacoustic section imaging. Images are acquired by rotating a sample in front of the cylindrical detector. With its length exceeding the size of the imaging object, it works as an integrating sensor and therefore allows reconstructing section images with the inverse Radon transform. Prior to the reconstruction the Abel transform is applied to the measured signals to improve the accuracy of the image. A resolution of about 100 µm within a section and of 500 µm between sections is obtained. Additionally, a series of images of a zebra fish is shown.

Impact of ZnO gate interfacial layer on piezoelectric response of AlGaN/GaN C-HEMT based ring gate capacitor

We report on a piezoelectric response investigation of AlGaN/GaN circular high electron mobility transistor (C-HEMT) based ring gate capacitor as a new stress sensor device to be potentially applied for dynamic high-pressure sensing. A ring gate capacitor of C-HEMT with an additional ZnO gate interfacial layer was used to measure the changes in the piezoelectric charge induced directly by the variation of piezoelectric polarization of both gate piezoelectric layers (AlGaN, ZnO) for harmonic loading at different excitation frequences. Our experimental results show that about 10 nm thick piezoelectric ZnO layer grown on ring gate/AlGaN interface of C-HEMT can yield almost a 60% increase in the piezoelectric detection sensitivity of the device due to its higher piezoelectric coefficient. A three-dimensional CoventorWare simulation is carried out to confirm the increase in the measured piezoelectric response of ZnO based ring gate capacitor of C-HEMT.

Piezoelectric annular array for large depth of field photoacoustic imaging

A piezoelectric detection system consisting of an annular array is investigated for large depth of field photoacoustic imaging. In comparison to a single ring detection system, X-shaped imaging artifacts are suppressed. Sensitivity and image resolution studies are performed in simulations and in experiments and compared to a simulated spherical detector. In experiment an eight ring detection systems offers an extended depth of field over a range of 16 mm with almost constant lateral resolution.

Optoacoustic methods for frequency calibration of ultrasonic sensors

The frequency response of ultrasonic detectors is commonly calibrated by finding their sensitivity to incident plane waves at discrete frequencies. For certain applications, such as the emerging field of optoacoustic tomography, it is the response to point sources emitting broadband spectra that needs to be found instead. Although these two distinct sensitivity characteristics are interchangeable in the case of a flat detector and a point source at infinity, it is not the case for detectors with size considerably larger than the acoustic wavelength of interest or those having a focused aperture. Such geometries, which are common in optoacoustics, require direct calibration of the acoustic detector using a point source placed in the relevant position. In this paper, we report on novel cross-validating optoacoustic methods for measuring the frequency response of wideband acoustic sensors. The approach developed does not require pre-calibrated hydrophones and therefore can be readily adopted in any existing optoacoustic measurement configuration. The methods are successfully confirmed experimentally by measuring the frequency response of a common piezoelectric detector having a cylindrically focused shape.

J044062 圧電ファイバ/金属多機能複合デノミイスを用いたパッシブ型粘性センサの開発([J04406]知的材料・構造システム(6))

We stadied a new viscous sensor using piezoelectric fiber/ metal multifunctional compound device. The produced viscous sensor is the structure which embedded the piezo electric fiber containing a metal core in aluminum matrices. When aluminum covers a piezo electric fiber, the sensor part is mechanically protected from the outside. Moreover, the aluminum cover is used also as an electrode. The viscous sensor which already embedded two piezo-electric fibers, oscillating excitation and detection, has been studied. Furthermore, by limiting to a use with sources of vibration, such as an engine of a car, the actuator which vibrates into a sensor part becomes unnecessary. The viscosity of a liquid is calculable by resonating a sensor part using the vibration from the outside, and detecting the vibration for the embedded piezo-electric fiber.

Simplified determination of bacterial contamination by Escherichia coli using a flow injection system with piezoelectric detection

A rapid and automated method was developed for the determination of bacterial contamination and using Escherichia coli as a model microorganism. The method involves the use of a sensor connected to a flow injection (FI) system. The sample is introduced through a flow injection system into a piezoelectric quartz crystal (PQC) flow-cell. The resulting change of the resonance frequency is related to the bacterial contamination in the sample. The parameters associated with the flow system and the conditions for introducing the sample culture were optimized. Calibration curves are linear in the range from 3.2 × 107 to 3.2 × 109 cfu per mL-1, with a correlation coefficient of 0.997. The reproducibility was between 3.1 and 7.6%, and the detection limit is 1.1 × 107 cfu per mL-1. The method allowed the determination of bacterial contamination in residual water and in samples of milk and chicken stock within 5 h, while the conventional plate count method requires 24 to 48 h. The results obtained by these two methods are in good agreement.

Electrogravimetric Real-Time and in Situ Michaelis−Menten Enzimatic Kinetics: Progress Curve of Acetylcholinesterase Hydrolysis

A piezoelectric detection of enzyme-modified surface was performed under Michaelis-Menten presumptions of steady-state condition. The approach herein presented showed promise in the study of enzymatic kinetics by measuring the frequency changes associated with mass changes at the piezoelectric crystal surface. Likewise, real-time frequency shifts, that is, dΔf/dt, indicated the rate of products formation from enzymatic reaction. In this paper, acetylcholinesterase was used as the enzymatic model and acetylcholine as substrate. The enzymatic rate has its maximum value for a short time during the kinetic reaction, for instance, during the first ten minutes of the reaction time scale. The values found for the kinetic constant rate and Michaelis-Menten constant were (1.4 ± 0.8) 10(5) s(-1) and (5.2 ± 3) 10(-4) M, respectively, in agreement with the values found in classical Michaelis-Menten kinetic experiments.

Study of the characteristics of a piezoelectric lead zirconate titanate radiation detector using a pulsed xenon source

The detector characteristics of piezoelectric lead zirconate titanate (PZT) were studied by directly irradiating a multilayered PZT detector with 400 MeV/n xenon ions. An extracted beam was processed with a rotating slit. Thus, passed through ∼103 xenon ions were available for 50 to 250 μs. The effect of polarization on the output signal was discussed, and the optimal electrode configuration was determined. The output signal appeared as an isolated pulse whose amplitude was qualitatively understood by the Bethe–Bloch formula. However, the calculated and the observed values differed depending on the rotation speed of the slit. A process that can explain the differences is presented here. The output signal appearing beyond the range of 400 MeV/n xenon ion beam was discussed. The sensitivity was compared with that obtained with hypervelocity collision of dust.

Molecularly imprinted polymer (MIP) based piezoelectric microgravimetry chemosensor for selective determination of adenine

An adenine-templated molecularly imprinted polymer (MIP) film, deposited on a poly(bithiophene) barrier film, served as the recognition element of a piezomicrogravimetric (acoustic) chemosensor. A 10 MHz AT-cut shear-thickness-mode bulk-acoustic-wave quartz crystal resonator with Pt film electrodes was used as the signal transducer. Adenine electrooxidation was prevented by the barrier film. The MIP film was deposited by electrochemical co-polymerization of two functional monomers of bis(bithiophene) derivatives, bearing either the 18-crown-6 or dioxaborinane substituent, in the presence of the adenine template. A strong base solution was then used to extract the template. Completeness of the template removal was substantiated by the UV–vis, XPS, DPV, and EIS measurements. The chemosensor performance was evaluated with the piezoelectric microgravimetry detection at QCM under FIA conditions using a carrier acetonitrile–water (1:1, v: v) mixed solvent solution. The linear dynamic concentration range extended from at least 0.1 to 1 mM for the 35 μL/min flow rate, and 100 μL volume of the injected adenine solution. The chemosensor selectivity allowed for discrimination of the adenine analyte from structurally and functionally related interferants, such as 2-aminopurine, guanine, and ascorbic acid. The determined from the FIA kinetic studies stability constant of the MIP–adenine complex, (18 ± 2.4) × 10 4 M −1, was much higher than that of the MIP–(2-aminopurine), (650 ± 90) M −1, MIP–guanine, (122 ± 11) M −1, and MIP–(ascorbic acid), (92 ± 10) M −1, complexes. The concentration limit of detection was as low as 5 nM adenine for the 35 μL/min flow rate, and 1 mL volume of the injected sample solution.

Feasibility of noncontact piezoelectric detection of photoacoustic signals in tissue-mimicking phantoms

The feasibility of air-coupled ultrasound transducers to detect laser-induced ultrasound from artificial blood vessels embedded in an optically scattering phantom is demonstrated. These air-coupled transducers allow new applications in biomedical photoacoustic imaging where contact with tissue is not preferred. One promising application of such transducers is the addition of photoacoustic imaging to the regular x-ray mammographic screening procedure.

Ultrasonic and Piezoelectric Investigations of Phase Transitions in Ferroelastic Cu6PS5(I,Br) Mixed Crystals

The ultrasonic velocity and attenuation anomalies were observed near the elastic phase transitions (PT) in the vicinity of 270 K in Cu 6 PS 5 (I,Br) mixed superionic crystals, where I was partially substituted by Br. We have shown that elastic anomalies at phase transition gradually decrease with increasing of iodine concentration in the material. The critical anomalies were described by relaxational Landau theory, which implies the increase of order parameter relaxation time: τ = τ o /(T c − T). The prefactor τ o increases with increasing iodine content in crystal. The ultrasonic anomalies near low temperature superionic phase transitions were weak. These transitions were observed using piezoelectric detection of ultrasonic waves by surface barrier. The temperature dependencies of detected by surface barrier signal were measured and it was shown that this method is very sensitive for indication of phase transitions in such superionic crystals.

Selective Histamine Piezoelectric Chemosensor Using a Recognition Film of the Molecularly Imprinted Polymer of Bis(bithiophene) Derivatives

A histamine piezoelectric (acoustic) sensor using a molecularly imprinted polymer (MIP) film has been devised and tested. The sensor comprises an electrodeposited MIP film as the recognition element and a 10 MHz AT-cut shear-thickness-mode bulk-acoustic-wave quartz crystal resonator with Pt film electrodes as the signal transducer. Preparation of the sensing film involved two consecutive electrochemical polymerizations, performed under cyclic voltammetric conditions, with the use of a supporting electrolyte of 0.1 M tetra-n-butylammonium perchlorate in acetonitrile. First, a poly(bithiophene) barrier film was deposited by electropolymerization on the Pt/quartz resonator to prevent histamine electro-oxidation and avoid possible contamination of the Pt electrode surface. Next, the histamine-templated MIP film was deposited by electropolymerization on top of this barrier film. For that purpose, two functional monomers of bis(bithiophene) derivatives, i.e., one bearing the 18-crown-6 and the other dioxoborinane substituent, were copolymerized in the presence of the histamine template. The consecutive growth of both these overlaid films was monitored with an electrochemical quartz crystal microbalance (EQCM). Subsequently, the histamine was extracted from MIP with 0.01 M NaOH for 12 h. The UV-vis and X-ray photoelectron spectroscopic measurements confirmed the completeness of the removal of the histamine template from the MIP film. The analytical performance of the chemosensor was assessed under flow injection analysis (FIA) conditions using the carrier 0.5 M HEPES buffer (pH = 7.5) solution and the piezoelectric microgravimetry detection at QCM. The negative peaks of resonant frequency linearly decreased with the increase of the histamine concentration in the range 10-100 mM for 150 microL/min flow rate, and 100 microL volume of the injected sample. The sensitivity of the chemosensor (0.33 Hz/mM) was more than twice as that of the chemosensor without the poly(bithiophene) barrier film (0.15 Hz/mM). The chemosensor performance was superior for selective histamine recognition if the poly(bithiophene) barrier film thickness exceeded 200 nm. The chemosensor discriminated histamine from functionally or structurally similar compounds, such as dopamine, tryptamine, and imidazole. Stability constants of the affinity complexes of MIP and analyte or the interfering agent were determined from kinetic studies. For the MIP-histamine complex, the stability constant thus evaluated was equal to 57.0 M(-1) being much higher than those for the MIP-tryptamine and MIP-dopamine complexes determined to be 10.7, and 6.4 M(-1), respectively. The concentration limit of detection was as low as 5 nM histamine if the carrier solution flow rate was as low as 35 microL/min and the injection sample volume as large as 1 mL.

Diagnostics of residual stress in metals with wideband surface acoustic pulses

A method for diagnostics of biaxial residual stress in metals with the use of short pulses of surface acoustic waves (SAWs) is discussed. Laser thermoelastic excitation of SAW pulses with a length of about 30 ns and piezoelectric detection by a specially designed wedgelike receiver with a high time resolution are used. Relative variations in the phase and group SAW velocities due to the presence of a weld are measured experimentally in two mutually perpendicular directions. The frequency range of measurements was 5–25 MHz, which corresponds to a depth of SAW penetration of about 120–600 μm. Measurements were conducted on samples made of 12X18H10T stainless steel with planar dimensions of 105 × 76 mm and thickness h = 8 mm, which were welded along the axis by an electron beam. The weld width was 5–7 mm. After the measurements, the samples were investigated by the fracture method based on the technique of a complete relief. The results of measurements are compared with the data obtained by fracture tests. The potential of the studied method is analyzed, and the measurement errors are estimated.

Laboratory calibration measurements of a piezoelectric lead zirconate titanate cosmic dust detector at low velocities

A cosmic dust monitor for use onboard a spacecraft is currently being developed using a piezoelectric lead zirconate titanate element (PZT). Its characteristics of the PZT sensor is studied by ground-based laboratory impact experiments using hypervelocity particles supplied by a Van de Graaff accelerator. The output signals obtained from the sensor just after the impact appeared to have a waveform that was explicitly related to the particle’s impact velocity. For velocities less than ∼6 km/s, the signal showed an oscillation pattern and the amplitude was proportional to the momentum of the impacting particle. For higher velocities, the signal gradually changed to a single waveform. The rise time of this single waveform was proportional to the particle’s velocity for velocities above ∼6 km/s. The present paper reports on results for the low velocity case and especially discusses the effect of an outer coating of the sensor with a paint, which is used to reduce heating by solar radiation.