Piezoelectric Quartz Crystal Research Articles

A New SPQC Biosensor for the Detection of a New Target of Escherichia/Shigella Genera Based on a Novel Method of Synthesizing Long-Range DNA.

The rapid and sensitive detection of Escherichia/Shigella genera is crucial for human disease and health. This study introduces a novel series of piezoelectric quartz crystal (SPQC) sensors for detecting Escherichia/Shigella genera. In this innovative biosensor, we propose a new target and novel method for synthesizing long-range DNA. The method relies on the amplification of two DNA probes, referred to as H and P amplification (HPA), resulting in the products of long-range DNA named Sn. The new target was screened from the 16S rRNA gene and utilized as a biomarker. The SPQC sensor operates as follows: the Capture probe is modified on the electrodes. In the presence of a Displace probe and target, the Capture can form a complex with the Displace probe. The resulting complex hybridizes with Sn, bridging the gap between the electrodes. Finally, silver wires are deposited between the electrodes using Sn as a template. This process results in a sensitive response from the SPQC. The detection limit of the SPQC sensor is 1 CFU/mL, and the detection time is within 2 h. This sensor would be of great benefit for food safety monitoring and clinical diagnosis.

Ultrasensitive Detection of Tumor Suppressor Gene Methylation by Piezoelectric Sensing Based on Enrichment of Transcription Activator-Like Effectors.

The detection of DNA methylation at cytosine/guanine dinucleotide (CpG) islands in promoter regions of tumor suppressor genes has great potential for early cancer screening, diagnosis, and prognosis monitoring. Nevertheless, achieving accurate, sensitive, cost-effective, and quantitative detection of target methylated DNA remains challenging. Herein, we propose a novel piezoelectric sensor (series piezoelectric quartz crystal (SPQC)) based on transcription activator-like effectors (TALEs) for detecting DNA methylation of Ras association domain family 1 isoform A (RASSF1A) tumor suppressor genes (R-5mC). The sensor employs TALEs-Ni magnetic beads to specifically recognize and separate the R-5mC, thereby improving the detection selectivity. The TALEs-Ni magnetic beads-R-5mC complex is sheared by a nucleic acid enzyme (DNAzyme) to release the single-stranded DNA (ST). ST initiates a catalyzed hairpin assembly (CHA) reaction on the surface of the electrode, which in turn triggers the hybridization chain reaction (HCR) and silver staining for enhanced detection sensitivity. The strategy exhibits a linear response in the detection of R-5mC in the range of 1 fM to 1 nM with a detection limit of 0.79 fM. R-5mC as low as 0.01% can be detected, even in the presence of large numbers of unmethylated DNA. The detection of R-5mC in circulating cell-free DNA (cfDNA) derived from clinical plasma specimens of lung cancer patients yielded satisfactory results.

Development of SPQC sensor based on the specific recognition of TAL-effectors for locus-specific detection of 6-methyladenine in DNA

N6-methyladenosine (6mA) plays a pivotal role in diverse biological processes, including cancer, bacterial toxin secretion, and bacterial drug resistance. However, to date there has not been a selective, sensitive, and simple method for quantitative detection of 6mA at single base resolution. Herein, we present a series piezoelectric quartz crystal (SPQC) sensor based on the specific recognition of transcription-activator-like effectors (TALEs) for locus-specific detection of 6mA. Detection sensitivity is enhanced through the use of a hybridization chain reaction (HCR) in conjunction with silver staining. The limit of detection (LOD) of the sensor was 0.63 pM and can distinguish single base mismatches. We demonstrate the applicability of the sensor platform by quantitating 6mA DNA at a specific site in biological matrix. The SPQC sensor presented herein offers a promising platform for in-depth study of cancer, bacterial toxin secretion, and bacterial drug resistance.

Rapid Detection of Broad-Spectrum Pathogenic Bacteria Based on Highly Sensitive Proton Response of the Nucleic Acid Amplification SPQC Platform.

Pathogenic bacteria significantly contribute to elevated morbidity and mortality rates, highlighting the urgent need for early and precise detection. Currently, there is a paucity of effective broad-spectrum methods for detecting pathogenic bacteria. We have developed an innovative proton-responsive series piezoelectric quartz crystal (PR-SPQC) platform for the broad-spectrum identification of pathogenic bacteria. This was achieved by retrieving and aligning sequences from the NCBI GenBank database to identify and validate 16S rRNA oligonucleotide sequences that are signatures of pathogenic bacteria but absent in humans or fungi. The hyperbranched rolling circle amplification, activated exclusively by the screened target, exponentially generates protons that are detected by SPQC through a 2D polyaniline (PANI) film. The PR-SPQC platform demonstrates broad-spectrum capabilities in detecting pathogenic bacteria, with a detection limit of 2 CFU/mL within 90 min. Clinical testing of blood samples yielded satisfactory results. With its advantages in miniaturization, cost efficiency, and suitability for point-of-care testing, PR-SPQC has the potential to be extensively used for the rapid identification of diverse pathogenic bacteria within clinical practice and public health sectors.

Rapid detection of nucleic acid sequences of pathogenic bacteria based on a series piezoelectric quartz crystal sensor with transcription activator-like effectors

Accurate and rapid detection of pathogenic bacteria is of great importance in the field of clinical diagnosis and food safety. Current methods for pathogenic bacteria detection have some problems in accurate, rapid and universal application. Here we proposed a pathogenic bacteria series piezoelectric quartz crystal (SPQC) sensor for achieving highly specific and sensitive detection of pathogenic bacteria. The universal sequences of common clinical pathogens screened by our group were used as detection targets. A new TALEs nuclease was synthesized as a recognition element, which recognizes double-stranded DNA at the level of a single base mismatch in the range of 17–19 bases. Targets could be specifically recognized by TALEs, resulting in the change of electrode surface, which would be further amplified by hybridization chain reaction and silver staining technique. Finally, the changes would be detected by SPQC system. This strategy was demonstrated to have excellent performance, enabling sensitive detection of targets with a detection limit of 25 cfu/mL in less than 3 h. What's more, the identification of single base mismatch could be achieved when the target ranging in length between 17 and 19 bases. The proposed method is rapid, accurate and easy universal application and expected to be applied in clinical diagnosis and food safety.

Prototype for chemical analysis and process intensification that is useful for research and teaching

This work describes the design, manufacturing and testing of a detection system useful to be applied with microTAS or other compact equipment, such as those needed for Process Intensification in Chemical Engineering. The detection is carried out by a Quartz Microbalance (QCM), based on Piezoelectric Quartz Crystals (PQC) of multiple frequencies, from tens of kHz to almost GHz. With this instrument, it is possible to detect particles and droplets in a gaseous flow, as well as vapors of volatile organic compounds. The system allows simultaneous measurement at five different points, and due to its modularity, such points can be positioned several centimeters apart from each other. The use in teaching is favored not only because of its low cost and modularity, and also due to its portability, i.e., its small size.

High-Sensitivity Chitin Nanofiber-Coated Series Piezoelectric Quartz Crystal Humidity Sensors

This paper fabricated a high-performance chitin nanofibers-coated interdigital electrode-piezoelectric quartz crystal (IDE-PQC) humidity sensor. Firstly, this paper investigated the influence of each Butterworth-Van Dyke equivalent parameter of the piezoelectric quartz crystal on the resonance characteristics of the IDE-PQC humidity sensor. Then, the results of MATLAB calculations revealed that the resonant frequency of the IDE-PQC humidity sensor changes larger (i.e., higher sensitivity) by increasing the PQC electrode area and decreasing the quartz wafer thickness. Next, the theoretical result was proved using advanced design system (ADS) simulation. Finally, the moisture-sensitive performances of IDE-PQC humidity sensors with different electrode areas and quartz wafer thicknesses were tested using chitin nanofibers as the moisture-sensitive material. The experimental results showed that the IDE-PQC humidity sensor with a larger electrode area and thinner quartz wafer thickness has higher sensitivity. This paper provides a new solution for building a high-performance series piezoelectric quartz crystal sensor.

Real‐Time Quantification of Cell Mechanics and Functions by Double Resonator Piezoelectric Cytometry – Theory and Study of Cellular Adhesion of HUVECs

AbstractCell mechanics is closely associated with cellular structure and function. However, the inability to measure both cellular force and viscoelasticity of statistically significant number of cells noninvasively remains a challenge for quantitative characterizations of various cellular functions and practical applications. Here a double resonator piezoelectric cytometry (DRPC), using AT and BT cut quartz crystals of the same frequency and surface morphology is developed to simultaneously quantify the cells‐generated forces (ΔS) and viscoelastic moduli (G′, G″) of a population of isolated single cells or cells with different degrees of cell‐cell interactions in a non‐invasive and real time manner. DRPC captures the dynamic mechanical parameters ΔS and G′, G″ during the adhesions of human umbilical vein endothelial cells (HUVECs) under different ligand densities of adhesion molecules fibronectin or Arg‐Gly‐Asp (RGD) modified on the gold surfaces of 9 MHz AT and BT cut quartz crystals, and different seeding densities of HUVECs. It is found that both the ligand density and cell seeding density affect the magnitudes of ΔS and G′, G″ and their correlations are revealed for the first time by DRPC. The validity of DRPC is further verified by mechanical changes of the cells in response to treatments with cytoskeleton regulators.

A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave Sensor.

A new method to analyse ammonia in freshwater, based on a piezoelectric quartz crystal coated with the metalloporphyrin chloro[5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato] manganese(III) is presented. A 9 MHz quartz crystal coated on both faces with an amount of porphyrin produced a frequency decrease of 21.4 kHz, which allowed ammonia in a 10.00 mL sample to be quantified in concentrations between 5 and 70 µg L−1, with a sensitivity of 0.60 Hz L µg−1, over a period of at least eight months. The proposed method has several advantages over the officially recommended indophenol spectrophotometric method: sample volume was reduced by a factor of 2.5, toxic reagents (phenol and sodium nitroprusside) were eliminated, analysing turbid samples presented no difficulty, and there was not only a significant time saving in solution preparation, but also in sample analysis time, which was reduced from 1 h to 2 min. No statistically significant differences (α = 0.05) were found both in the mean and precision of the results obtained for ammonia in water samples collected from domestic wells, analysed by this new method and by the indophenol spectrophotometric method. Furthermore, the proposed method would allow the individual quantification, with similar sensitivity, of amines and ammonia within a single analytical run.

Low Frequency Magnetoelectric Sensor Without Bias Using Laminated Metglas/Quartz/Metglas Structure

Tremendous progress has been made on boosting the performance of magnetoelecric sensor to detect low frequency magnetic field signal by frequency multiplication based on magnetolectric composites. In this paper, a novel magnetoelectric sensor based on the laminated Metglas/piezoelectric quartz crystal/Metglas composites structure is presented. The Metglas foils are bonded symmetrically on both sides of the X-cut quartz crystal plate with epoxy. Experiments showed that the ME composites sensor was able to achieved a limit of detection of 11 pT for a low frequency magnetic field 1 Hz without any bias field through frequency multiplication method. The noise power spectrum density of the sensor has also been tested to be 3.93·10-6 V/Hz1/2 at 1 Hz. The results indicate that the proposed sensor has favorable features, which provides a cost-effective and high-performance approach for low frequency magnetic field measurement. Keywords: Low frequency, limit of detection, magnetoelectric sensor, piezoelectric quartz crystal.

Crystallization of GeO2 thin films into α-quartz: from spherulites to single crystals

Piezoelectric quartz (SiO2) crystals are widely used in industry as oscillators. As a natural mineral, quartz and its relevant silicates are also of interest in geoscience and mineralogy. However, the nucleation and growth of quartz crystals are difficult to control and not fully understood. Here we report successful solid-state crystallization of thin film of amorphous GeO2 into quartz on various substrates, including Al2O3, MgAl2O4, MgO, LaAlO3 and SrTiO3. At relatively low annealing temperatures, the crystallization process is spherulitic: with fibers growing radially from the nucleation centers and the crystal lattice rotating along the growth direction with a linear dependence between the rotation angle and the distance to the core. For increasingly higher annealing temperatures, quartz crystals begin to form. The edges of the sample play an important role in facilitating nucleation followed by growth sweeping inward until the whole film is crystallized. Control of the growth allows single crystalline quartz to be synthesized, with crystal sizes of hundreds of microns achieved on sapphire substrates, which is promising for further piezoelectric applications. Our study reveals the complexity of the nucleation and growth process of quartz and provides insight for further studies.

UV Light Detection Using Resonance Frequency of Piezoelectric Quartz Crystal

This article reported about the ultraviolet (UV) radiation effect on the resonance frequency response of a AT-cut piezoelectric quartz crystal. A large resonance frequency upshift was observed when the quartz crystal was irradiated by UV light of 355-nm wavelength using a Q-switched pulsed Nd:YVO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> UV laser. The dynamic frequency response behavior was systematically investigated by illuminating the quartz crystal with UV light in which the UV intensity was varied with time in staircase- and linear pulse-shaped patterns. From the experimental analysis, we measured the limit of detection and the sensitivity of the quartz crystal, which are about 0.5 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 0.706 Hz/(mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), respectively. For a constant UV irradiation, a moderate response (<;10 s) and recovery (<;10 s) times were achieved during the on and off cycles of the UV light. The short-term repeatability and maximum operating limit of AT-cut quartz crystal were also further studied upon exposure to UV light with different intensities. In this work, we not only demonstrate the impact of UV irradiation on quartz crystal but also discuss the mechanism of upshift in resonance frequency upon exposure to UV light. This study shows the applicability of quartz crystal for the detection of UV light.

Vibration Characteristics of Force Signal for Single Diamond Grit Scratching Process

Scratching force is a significant factor to evaluate the characteristics of single diamond grit scratching process. In this paper, experimental study was carried out to investigate the vibration characteristics of force signals during the scratching process. A precise multicomponent dynamometer is employed in the force measurement during a single diamond grit scratching on pure copper. The frequencies of the vibration section of force signals with different scratching parameters are calculated and analyzed. The influence of force signal vibration on the measuring accuracy of dynamometer is systematically analyzed further. The results show that higher scratching speed and larger scratching depth lead to larger vibration amplitudes of the force signals. Strong impact on the quartz piezoelectric crystal of dynamometer, which is produced indirectly by single diamond grit scratching process, leads to the vibration of scratching force signal. The first semi-sinusoidal force signal is the actual scratching force. The vibration of the scratching force signal has little effect on the measuring accuracy of the dynamometer.

Electrochemical biosensor for rapid detection of bacteria based on facile synthesis of silver wire across electrodes

The early detection of bacteria is of critical importance in addressing serious public health problems. Here, an electrochemical biosensor for rapid detection of bacteria based on facile synthesis of silver wire across electrodes was constructed. High-variable region of 16S rRNA of bacteria was used as biomarker. Polymerase-free synthesis of silver wire was introduced into electrochemical signal transduction to improve the sensitivity of electrochemical detection. The construction biosensor of proposed method is as follows: Metastable hairpin probe H1 was modified on electrode surface, biomarker can open the stem-loop structure of H1 and activates HCR. The alternate opening of the stem-loop structure of H1 and H2-AuNPs finally results in the formation of long double-stranded DNA-RNA (HCR products) -AuNPs. The formed AuNPs modified HCR products was blown in one direction using N2 to across the electrode gap. Using this HCR products as template, the silver wire was formed between the electrodes by silver deposition, and resulted in sharp change in electrical parameters of electrode. As the proof-of-concept work, multichannel series piezoelectric quartz crystal (MSPQC) was utilized as detector. The detection of Staphylococcus aureus in the concentration range from 50 to 107 CFU/mL within 100 min was achieved. The detection limit was 50 CFU/mL. Escherichia coli, Salmonella enteritidis, Listeria innocua, Pseudomonas aeruginosa and Streptococcus pneumoniae did not interfere the detection results. This newly proposed electrochemical biosensor is simple, rapid and exhibit high signal-to-noise ratio, it has great potential for being applied in food safety monitoring and clinical diagnosis.

Preserve Your Books through the Smell.

The identification of paper composition, pH, early signs of paper degradation, and emitting volatile organic compounds (VOCs) are mandatory for effective preventive conservation of paper/books. Sampling restrictions in the analysis of cultural heritage materials limit the choice of appropriate analytical methods. Solvent-free analytical techniques with nondestructive sampling are needed. Addressing this challenge, an electronic nose based on six-coated piezoelectric quartz crystals was assembled and used to analyze VOCs emitted from books. Careful selection of sensor coatings and cluster analysis allowed us to achieve a clear distinction between cotton/linen rag and wood pulp paper, and among the letter group, the discrimination between papers manufactured from alkaline and acidic stocks. This six-element sensor array was therefore able to replace destructive tests as the ones ordinarily used for paper pH measurements. The same electronic nose was able to separate aged pale-yellow paper, a visible initial sign of paper degradation, from well-preserved still white papers, even when made from the same raw material. One of the used sensors detected furfural, often seen as a marker of cellulose degradation, at lower levels than the detection limit found in the literature with gas chromatography-mass spectrometry, a much more complex bulky and expensive instrument.

Design and Performance Analysis of a Lateral Thrust Measuring Device

This paper takes multi-dimensional force measurement of lateral force power unit as research objective, and a piezoelectric multi-dimensional force measuring device with piezoelectric quartz crystal as force sensitive component is designed. First, the mathematical model between sensors’ output and measured lateral force is established by theoretical derivation. The relationship between the force applied to measured object and measuring device’s output is obtained through the finite element analysis, which verifies the measurement performance of measuring device. On the other hand, through ANSYS model analysis, a conclusion that the first natural frequency of measuring device is 1467.8Hz can be obtained, and the dynamic performance of measuring device is good, which enables accurate measurement of real-time varying lateral force.

The construction of Mycobacterium tuberculosis 16S rDNA MSPQC sensor based on Exonuclease III-assisted cyclic signal amplification

Tuberculosis caused by Mycobacterium tuberculosis (M. tuberculosis) remains one of the most serious infectious diseases all over the world. The key to reduce the spread and mortality rate of tuberculosis is to develop faster and more sensitive approaches for detection of M. tuberculosis. However, current detection methods can not meet the requirements of rapid clinical M. tuberculosis detection in terms of detection time. Herein, a new 16S rDNA multichannel series piezoelectric quartz crystal (MSPQC) sensor based on Exonuclease III (Exo III)-aided target recycling has been developed for rapid detection of M. tuberculosis. The specific 16S rDNA fragment of M. tuberculosis was used as biomarker, DNA capture probes complementary to the biomarker were designed and modified on the surface of AuNPs. The Exo III which could recognise hybrid duplexes and selectively digest DNA capture probe was used to assist digestion cycle by digesting DNA capture probe and releasing the intact target fragment. After all DNA probes loading on the surface of AuNPs were removed, the surface of AuNPs was exposed and conductive connection was formed between the nanogap network electrode by self-catalytic growth of exposed AuNPs in the glucose and HAuCl4 solution. This resulted in sensitive response of M. tuberculosis sensor and M. tuberculosis was detected by recording this response. The limit of detection (LOD) of the method was 20 CFU/mL and the detection time was less than 3 h. It was expected to be widely used in detection methods of M. tuberculosis.

A supersensitive MSPQC bacterium sensor based on 16S rRNA and “DNA-RNA switch”

The early detection of bacterium plays a significant role in addressing serious public health issues. In this paper, a supersensitive multichannel series piezoelectric quartz crystal (MSPQC) sensor of bacterium based on 16S rRNA and “DNA-RNA switch” was constructed. The fragment in specific region of 16S rRNA was used as the biomarker of bacterium to ensure high specificity and to achieve the accurate judgment of microbial vitality. “DNA-RNA switch” was designed to conduct two electrodes by switching insulated “gene-link” into conductive “silver-link”, which achieved the super-sensitivity of MSPQC to bacteria. To demonstrate the feasibility of this strategy, a proof-of-concept method for Escherichia coli (E. coli) assay was designed. The detection limit was down to 2 cfu/mL. Staphylococcus aureus, Salmonella enteritidis, Listeria innocua and Pseudomonas aeruginosa did not interfere with the detection results. Proposed method was highly sensitive, and specific for bacterium detection, which might find widely use in early detection of bacterium in the field of public safety monitoring and clinical diagnosis.

Mycobacterium tuberculosis strain H37Rv Electrochemical Sensor Mediated by Aptamer and AuNPs-DNA.

The accurate and rapid detection of Mycobacterium tuberculosis ( M. tuberculosis) is essential for the effective treatment of tuberculosis. In this article, we propose an electrochemical sensor to detect M. tuberculosis reference strain H37Rv. The sensor contains an H37Rv aptamer and oligonucleotides modified with gold nanoparticles (AuNPs-DNA). An H37Rv aptamer screened by our laboratory was used as the recognition probe. The change in frequency shift mediated by AuNPs-DNA in the presence of H37Rv was detected using a multichannel series piezoelectric quartz crystal (MSPQC) system. Three oligonucleotides modified with gold nanoparticles were designed. These oligonucleotides contained 12, 12, and 13 bases that hybridized with the 37-nt H37Rv aptamer. H37Rv aptamer was immobilized on the gold electrode surface by Au-S bonds. A conductive-layer was then formed by sequential hybridization of the aptamer with the three designed AuNPs-DNAs. When H37Rv was present, it specifically bound to the aptamer, resulting in the detachment of AuNPs-DNA from the electrode. The conductive layer was thereby replaced by a nonconductive complex of aptamer and bacteria. These changes were monitored by the MSPQC system. The proposed sensor is rapid, specific and sensitive, the detection time was 2 h. The detection limit was 100 cfu/mL. This sensor would be of great benefit for the early clinical diagnosis of tuberculosis.

A new aptamer/polyadenylated DNA interdigitated gold electrode piezoelectric sensor for rapid detection of Pseudomonas aeruginosa

Rapid detection of Pseudomonas aeruginosa (P. aeruginosa) is of great importance for accurate diagnosis and treatment of infected patients. In this study, a novel method was developed for the selective detection of P. aeruginosa by combing the sandwich type complex of magnetic bead/aptamer/polyadenylated-DNA with the sensitive detection platform of gold (Au) interdigital electrode connected to a multichannel series piezoelectric quartz crystal (Au IDE-MSPQC) system. Here, the magnetic bead (MB) was used as carrier for immobilization of the aptamer of P. aeruginosa. Polyadenylated DNA was bound to the aptamer through complementary strand pairing. When the P. aeruginosa was present in the sample solution, the polyadenylated DNA was replaced by the P. aeruginosa because of the specific interaction between P. aeruginosa and its aptamer. The released polyadenylated DNA strand in the detected solution could adsorb onto the surface of Au IDE by virtue of the strong interaction between adenine (A) and Au IDE, and result in sensitive frequency shift response of the MSPQC sensor. The limits of detection (LOD) of the method were as low as 9 CFU/mL in buffer and 52 CFU/mL in simulated blood sample. The proposed method was successfully applied to the selective detection of P. aeruginosa in blood samples. The constructed sensor is expected to find application for the rapid detection of P. aeruginosa in environment, food and clinical diagnosis.