Surface Of Piezoelectric Crystal Research Articles

Status of X-ray Acoustooptics at the Institute of Microelectronics Technology Russian Academy of Sciences

The electrical measurement method, scanning electron microscopy method and high-resolution X-ray diffraction method have been used to investigate the process of the surface acoustic wave (SAW) propagation in a LiNbO3 ferroelectric crystal. Measurement of the amplitude-frequency response provides information on the losses in the acoustoelectronic device during the process of the SAW propagation. The scanning electron microscopy method permits to visualize the SAW on the surface of piezoelectric crystals in the real-time mode and to observe diffraction phenomena in acoustic beam. The X-ray diffraction method is sensitive to the crystal lattice distortions by surface acoustic wave and allows determining the SAW amplitudes.

Biomolecular Piezoelectric Materials for Biosensors

Piezoelectric biosensors are a type of analytical equipment that works based on recording affinity interactions. A piezoelectric platform, also known as a piezoelectric crystal, is a sensor component that works on the premise of oscillations changing according to the presence of a mass on the piezoelectric crystal surface. Owing to their high piezoelectricity, biocompatibility, as well as different electrical properties, biomolecular piezoelectric materials are thought to be promising candidates for future piezoelectric biosensors. When biological components in the human body are stressed, they are estimated to produce electric fields that promote cell growth and repair. As a by-product, piezoelectricity research in biological tissues and their elements has drawn much attention recently. This article specifies the principle of the advancement in piezoelectricity research of representative biomolecular materials, which are nucleic acids such as amino acids (DNA, RNA), peptides, proteins, and viruses. We also explored the origins and processes of piezoelectricity in biomolecular materials for biosensor application. Various advantages of using piezoelectric biomolecular materials for biosensor applications are elaborated. Lastly, a comprehensive idea of future challenges and discussion are provided.

Development of fast prototyping laser technique for production of surface acoustic wave gyroscopes

Solid-state micromechanical gyroscopes based on surface acoustic waves (SAW) have good vibration and shock resistance because of absence of elastic suspensions, ability to work at 50 000 g loads, small dimensions, cheap in mass production, etc. Unfortunately, there are some limits for further development of such gyroscopes because it requires prototype production in small series. In this study we have investigated laser ablation method to solve this problem. Idea of this method is to evaporate unnecessary metallization from the piezoelectric crystal surface, e.g. to “draw” the electrode topology with a powerful laser beam. Main advantages of the method are as follows: possibility of fast and cheap sensors prototyping even with complicated topologies; reduction of the number of production process stages; possibility of topology correction (especially in case of transparent crystal housing); operation with thicker metal layers then traditional photolithography method, etc.

Quartz Crystal Microbalance Detection of Aflatoxin B1 by Self-Assembled Monolayer Technique

Background: New biosensor techniques allowing detection of low concentrated substances show a great variety nowadays. The construction of a system with modified quartz as a part of a Quartz Crystal Microbalance (QCM) techniques helps the detection and confirmation of low toxin concentrations in a sample. Objective: The study aims to allow the application of methods for preparation and modification of the gold surface of piezoelectric crystal for detection of aflatoxin B1(AFB1) in the concentration range 0.2 - 2.0 µg/L by QCM technique (quartz - crystal microbalance). Methods: The procedure for the preparation of quartz crystal sensors for experimental purposes was performed. The quartz surface was activated and covered with self-assembled monolayer to immobilize antibody (rabbit anti-aflatoxin B1) for the detection of antigen - antibody reaction. Results: The G” corresponds to viscous properties of the material, during applied deformation of the material in the presence of different concentrations, which revealed in the sensitivity of the used resonator. Conclusion: Detection of toxic pollutants may be achieved via QCM methods, ultrasound resonator and piezoelectric quartz techniques for measurement. These techniques allow detection of significantly low concentrations of toxic pollutants, in particular, AFB1, compared to analysis with direct and indirect ELISA immunoassays.

Design and Implementation of a Cost Effective Quartz Crystal Microbalance System for Monitoring Small Changes on any Surface

Quartz crystal microbalance systems are widely used in different fields from biology to electronic. Those devices are very sensitive to mass changes on the piezoelectric crystal surface in nano gram scale and therefore can be used to detect even a single virus on surface of any substance. Although they are very practical and versatile, they are sold with very high prices and thus hindering the usage for someone with tight research budget. In this work, we try to find a cost effective solution and bring this device into the price range on two to three orders of magnitude lower than the commercial counterparts. For that purpose, we develop a cost effective quartz crystal microbalance system using a cost effective microcontroller and a typical oscillator circuit and the final product can be used in different fields to detect the mass change on any surface caused by different reactions or effects.

Frequency dependence of surface acoustic wave swimming.

Surface acoustic waves (SAWs) are elastic waves that can be excited directly on the surface of piezoelectric crystals using a transducer, leading to their exploitation for numerous technological applications, including for example microfluidics. Recently, the concept of SAW streaming, which underpins SAW microfluidics, was extended to make the first experimental demonstration of ‘SAW swimming’, where instead of moving water droplets on the surface of a device, SAWs are used as a propulsion mechanism. Using theoretical analysis and experiments, we show that the SAW swimming force can be controlled directly by changing the SAW frequency, due to attenuation and changing force distributions within each SAW streaming jet. Additionally, an optimum frequency exists which generates a maximum SAW swimming force. The SAW frequency can therefore be used to control the efficiency and forward force of these SAW swimming devices. The SAW swimming propulsion mechanism also mimics that used by many microorganisms, where propulsion is produced by a cyclic distortion of the body shape. This improved understanding of SAW swimming provides a test-bed for exploring the science of microorganism swimming, and could bring new insight to the evolutionary significance for the length and beating frequency of swimming microbial flagella.

Overview of Piezoelectric Biosensors, Immunosensors and DNA Sensors and Their Applications.

Piezoelectric biosensors are a group of analytical devices working on a principle of affinity interaction recording. A piezoelectric platform or piezoelectric crystal is a sensor part working on the principle of oscillations change due to a mass bound on the piezoelectric crystal surface. In this review, biosensors having their surface modified with an antibody or antigen, with a molecularly imprinted polymer, with genetic information like single stranded DNA, and biosensors with bound receptors of organic of biochemical origin, are presented and discussed. The mentioned recognition parts are frequently combined with use of nanoparticles and applications in this way are also introduced. An overview of the current literature is given and the methods presented are commented upon.

Surface acoustic wave devices for chemical sensing and microfluidics: A review and perspective.

Surface acoustic waves (SAWs), are electro-mechanical waves that form on the surface of piezoelectric crystals. Because they are easy to construct and operate, SAW devices have proven to be versatile and powerful platforms for either direct chemical sensing or for upstream microfluidic processing and sample preparation. This review summarizes recent advances in the development of SAW devices for chemical sensing and analysis. The use of SAW techniques for chemical detection in both gaseous and liquid media is discussed, as well as recent fabrication advances that are pointing the way for the next generation of SAW sensors. Similarly, applications and progress in using SAW devices as microfluidic platforms are covered, ranging from atomization and mixing to new approaches to lysing and cell adhesion studies. Finally, potential new directions and perspectives on the field as it moves forward are offered, with a specific focus on potential strategies for making SAW technologies for bioanalytical applications.

A piezoelectric immunosensor for the rapid detection of p16INK4a expression in liquid-based cervical cytology specimens

A piezoelectric immunosensor was developed for the detection of p16INK4a, a protein that is expressed in liquid-based cervical cytology specimens and has been proved to be linked cervical cancer. Mouse polyclonal antibody against p16INK4a was bound onto the piezoelectric crystal surface in an ordered orientation using protein A. The antibody on the crystal could specifically adsorb p16INK4a and changes in the mass of the crystal would led to frequency shift. The supernatants from different clinical samples, including various cervical lesions, containing different concentration of p16INK4a were used for testing. Under the optimized conditions, the frequency shifts were linearly dependent on the antigen concentration in the range of 50–1200ngmL−1. The device showed a short analysis time (less than 30min), good reproducibility (could be reused six times without any detectable loss of activity), stability (the immunosensor was stable for more than eight weeks when stored over silica gel blue at 4°C), and specificity. Attempts have been made to use the sensor for the initial screening for cervical lesion in cervical cytology specimen, and the relationship between cytologic and histologic findings, p16INK4a expression in various cervical lesions, including carcinoma been investigated.

Surface acoustic wave propagation in graphene film

Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

Исследование объемных акустических волн СВЧ-диапазона, возбужденных встречо-штыревым преобразователем

Excitation of bulk and surface acoustic waves with the interdigital transducer (IDT), which is deposited on the surface of piezoelectric crystal, is widely used in the development of devices in acoustoelectronics and in the design of the microwave acousto-optic deflectors. Excitation of bulk acoustic waves by IDT in the devices on surface acoustic waves leads to the appearance of spurious signals. At the same time excitation of bulk acoustic waves with IDT from the surface of lithium niobate crystals allows creating high frequency acousto-optic deflectors, which makes possible to significantly simplify the technology of their production. Therefore, significant attention is paid to the task of excitation and distribution of bulk acoustic waves with IDT including recent times by the method of simulation of their excitation and distribution. The obtained theoretical results require experimental verification. This paper documents the visualization of acoustic beams excited with IDT from the XY-surface of lithium niobate crystals. The Bragg cells with LiNbO3 crystals coated with IDT with a different period of electrodes were manufactured for the experimental research of excitation and distribution of bulk acoustic waves. Visualization results have shown that the acoustic waves excited with IDT distribute in both the Fresnel zone and the Fraunhofer zone. The length of these zones is caused by individual elementary emitters of which consists the IDT (by their size). At the same time the far zone for IDT is located at distances much greater than the actual size of the LiNbO3 crystals. This peculiarity is not always taken into account when calculating diffraction. The achieved results can be used to design high-frequency acousto-optic devices, as well as in the development of devices based on surface acoustic waves.

Mass Sensitivity Evaluation and Device Design of a LOVE Wave Device for Bond Rupture Biosensors Using the Finite Element Method

The LOVE wave devices based on a number of composite structures have been designed and simulated in this paper for use as a bond-rupture biosensor. Bond-rupture biosensors use acoustic energy to probe the bond strength between the sensor substrate and the analyte. The sensitivity and displacement of LOVE wave sensors can be implemented due to energy concentration inside a guiding layer on the surface of a piezoelectric crystal. The choice of substrate and guiding layer material is the critical basic elements in the proper design of a LOVE wave biosensor applications. Finite element method (FEM) is a suitable numerical method to analyze and design the LOVE wave device. A 3-D FEM model has been created and defined to simulate the displacement response of the acoustic wave system. The LOVE wave can be clearly observed, and the total surface displacement can reach a value of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-11</sup> m, which can easily induce the bond rupture between antibody and antigen. A 2-D model has been established to simulate the mass sensitivity with different composite structures of 128° YX LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , 36° YX LiTaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , ST-quartz-PMMA and 128° YX LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , and 36° YX LiTaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and ST-quartz-SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . These results indicate that the 128° YX LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> PMMA is the most suitable for bond rupture biosensors due to its high sensitivity and maximum displacement on the surface of piezoelectric crystal.

Characterization of a Protein Using Saw Resonator

Surface Acoustic Wave (SAW) propagation on the surface of a piezoelectric crystal is used as a carrier of information. SAW Sensors are micro-electromechanical systems (MEMS) in which high frequency acoustic waves travel close to the surface of a piezoelectric substrate. Because of confined acoustic energy near the surface within the range of one acoustic wavelength, SAW devices are highly sensitive for surface perturbation such as molecular absorption or adsorption and change of viscoelastic properties. Surface acoustic wave (SAW) devices are very promising in providing a high-performance sensing platform with wireless and remote operational capabilities. Research focus is on studying methods to characterize conductance, susceptance, viscosity, and other properties of protein samples, like albumin using SAW related resonator devices quickly and inexpensively using quantities of less than one Nano-liter. Applied pressure or bending of the quartz sets up a condition where a separation of charge occurs (due to change in dipole moment density). The potential difference is proportional to the magnitude of stress. When a mass is deposited on the electrode the resultant decrease in resonant frequency can detect mass changes at nanogram level. We propose to advance the sensitivity of the characterization by use of quartz SAW resonators since they can operate at much higher frequency than bulk wave oscillators.

Experimental estimation of dijcoefficients of piezoelectric materials by means of optical microscopy

The properties of multiferroic and specifically piezoelectric (PE) materials are, nowadays, intensively investigated by means of well established, however relatively complicate methods. In this work we present a method for the direct visual demonstration of the underlying electro-mechanical processes occurring in PE materials and the estimation of the respective coefficients dij . The method is based on the utilization of optical microscopy for the local observation of the deformation of a PE specimen upon application of an electric field. The direct comparison of the snapshots obtained before and after application of the electric field and simple algebraic calculations enables the estimation of the dij coefficients. The method was evaluated in unpoled single crystals of 0.71Pb(Mg1/3 Nb2/3 )O3 –0.29PbTiO3 , at room temperature. Various locations of each crystal surface were surveyed. Non-homogeneous electro-mechanical response was observed. Accordingly, the estimated dij coefficients depended on the specific location of the crystal surface. Specifically, the dzx coefficient ranged within 500-1000 pm/V over the investigated locations (for electric fields E electro-mechanical processes occurring at the surface of PE crystals and clarifies how these observations can be quantified through the respective dij coefficients.

Leaky-surface-wave generated acoustic beam displacement upon reflection in lithium tantalate crystals

The non-specular reflection of a leaky surface acoustic wave radiated beam from the surface of piezoelectric lithium tantalate crystal has been investigated using an acoustoelectric and acousto-optic technique. The Schoch-type beam displacement upon reflection strongly depends on whether the surface is free or metalized. This effect is attributed to the excitation (on the reflecting surface) of the leaky surface wave, the acoustoelectric attenuation of which strongly depends on the surface conductivity.

Ultratrace detection of C-reactive protein by a piezoelectric immunosensor based on Fe3O4@SiO2 magnetic capture nanoprobes and HRP-antibody co-immobilized nano gold as signal tags

An ultra-sensitive multiplexed signal amplified piezoelectric immunosensor for the detection of C-reactive protein (CRP) in serum was developed. Firstly, a sandwich-type immunoreaction was made between the capture probe [silicon dioxide-coated magnetic Fe3O4 nanoparticles (MNPs) labeled with the primary CRP antibody (MNPs-CRP Ab1)], CRP (different concentrations), and signal tag [horseradish peroxidase (HRP) coupled with the HRP linked secondary CRP antibody co-immobilized on gold nanoparticles (AuNPs-HRP/HRP-CRP Ab2)]. The immunocomplex was subsequently exposed to 3-amino-9-ethylcarbazole (AEC) and hydrogen peroxide. MNPs-CRP Ab1 capture probe could not only improve the CRP enrichment to amplify the signal through magnetic separation, but also be readily immobilized on the electrode by an external magnet to prepare the sensor. The signal tag could immobilize vast HRP, which could catalyze and yield more AEC's insoluble oxidation product on piezoelectric crystal surface, also resulting in the amplified change in frequency response (Δf=f−f0). Thus the multiplex signal amplification was achieved. The Δf was proportional to CRP concentration from 0.001 to 100ngmL−1 with a low detection limit of 0.3pgmL−1. The optimum conditions were studied in detail. The proposed method could provide a fast, simple, and sensitive way for the clinical analysis of ultratrace CRP in heart diseases.

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.

Preparation and characterization of ethylenediamine and cysteamine plasma polymerized films on piezoelectric quartz crystal surfaces for a biosensor

This paper describes a method for the modification of quartz crystal surfaces to be used as a transducer in biosensors that allow recognition and quantification of certain biomolecules (antibodies, enzymes, proteins, etc). Quartz crystal sensors were modified by a plasma based electron beam generator in order to detect the level of the toxin histamine within biological liquids (blood, serum) and food (wine, cheese, fish etc.). Cysteamine and ethylenediamine were used as precursors in the plasma. After each modification step, the layers on the quartz crystal were characterized by frequency measurements. Modified surfaces were also characterized by contact angle, X-ray photoelectron spectroscopy and atomic force microscopy to determine the physical and chemical characteristics of the surfaces after each modification. Finally, the performance of the sensors were tested by the response to histamine via frequency shifts. The frequency shifts of the sensors prepared by plasma polymerization of ethylenediamine and cysteamine were approximately 3230 Hz and 5630 Hz, respectively, whereas the frequency change of the unmodified crystal surface was around 575 Hz.

Acoustic waves in the vicinity of the normal to the surface of piezoelectric crystals

The acoustic wave propagation in the vicinity of the normal to the plane surface confining a piezoelectric crystal of arbitrary symmetry is theoretically studied. An octet formalism and a perturbation theory have been put forward to describe the wave fields in the region of concern. The developed mathematical approach has been applied to several problems. Specifically, the derivation of the transfer matrix for the normal direction to the surface has been discussed. Furthermore, we have discussed how to estimate the electric potential induced outside the piezoelectric material by a normally incident wave. In addition, an analytical expression has been derived for the numerical factor in the function describing the asymptotic behavior of quasi-electrostatic Green's function for half-infinite piezoelectric substrates at small values of the wave vector.

Mechanomyographic and electromyographic responses to eccentric muscle contractions

Little is known regarding the modulation of torque during eccentric muscle actions. Mechanomyographic (MMG) and electromyographic (EMG) signals have been used to examine motor control strategies. The purpose of this study was to examine the MMG and EMG amplitude and frequency in relation to torque during eccentric muscle contractions. Eight women performed eccentric leg extension muscle contractions at 10-100% of peak torque (PT). A piezoelectric crystal contact sensor and bipolar surface electrodes were placed on the vastus medialis to detect the MMG and EMG signals. Polynomial regression analyses indicated that EMG amplitude (r(2)=0.994) and MMG wavelet center frequency (CF) (r(2)=0.846) increased linearly to 100% eccentric PT, whereas there were no significant relationships for EMG wavelet CF or MMG amplitude and eccentric torque. These results suggested that eccentric torque is primarily modulated through changes in motor unit firing rate.