Series Piezoelectric Quartz Crystal Research Articles

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.

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.

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.

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.

Selection of a new Mycobacterium tuberculosis H37Rv aptamer and its application in the construction of a SWCNT/aptamer/Au-IDE MSPQC H37Rv sensor

A rapid and accurate detection method for Mycobacterium tuberculosis (M. tuberculosis) is essential for effectively treating tuberculosis. However, current detection methods cannot meet these clinical requirements because the methods are slow or of low specificity. Consequently, a new highly specific ssDNA aptamer against M. tuberculosis reference strain H37Rv was selected by using the whole-cell systematic evolution of ligands by exponential enrichment technique. The selected aptamer was used to construct a fast and highly specific H37Rv sensor. The probe was produced by immobilizing thiol-modified aptamer on an Au interdigital electrode (Au-IDE) of a multichannel series piezoelectric quartz crystal (MSPQC) through Au-S bonding, and then single-walled carbon nanotubes (SWCNTs) were bonded on the aptamer by π-π stacking. SWCNTs were used as a signal indicator because of their considerable difference in conductivity compared with H37Rv. When H37Rv is present, it replaces the SWCNTs because it binds to the aptamer much more strongly than SWCNTs do. The replacement of SWCNTs by H37Rv resulted in a large change in the electrical properties, and this change was detected by the MSPQC. The proposed sensor is highly selective and can distinguish H37Rv from Mycobacterium smegmatis (M. smegmatis) and Bacillus Calmette-Guerin vaccine (BCG). The detection time was 70min and the detection limit was 100cfu/mL. Compared with conventional methods, this new SWCNT/aptamer/Au-IDE MSPQC H37Rv sensor was specific, rapid, and sensitive, and it holds great potential for the early detection of H37Rv in clinical diagnosis.

A novel method for the rapid detection of microbes in blood using pleurocidin antimicrobial peptide functionalized piezoelectric sensor

The rapid detection of microbes is critical in clinical diagnosis and food safety. Culture-dependent assays are the most widely used microbial detection methods, but these assays are time-consuming. In this study, a rapid microbial detection method was proposed using a pleurocidin/single-walled carbon nanotubes/interdigital electrode-multichannel series piezoelectric quartz crystal (pleurocidin/SWCNT/IDE-MSPQC) sensor. The selected pleurocidin antimicrobial peptide served as a recognition probe that exhibits broad-spectrum antimicrobial activity and the SWCNT acted as the electronic transducer and cross-linker for the immobilization of pleurocidin on the IDE. The response mechanism of the sensor was based on the specific interaction between pleurocidin and the microbe causing pleurocidin to detach from the SWCNT modified IDE, resulting in a sensitive frequency shift response of the MSPQC. Microbes that may be clinically present in the bloodstream during an infection were successfully detected by the proposed method within 15min. The developed strategy provides a new universal platform for the rapid detection of microbes.

Novel S-MSPQC cell sensor for real time monitoring the injury of endothelial cell by LPS and assessing the drug effect on this injury

A novel square Au microelectrode multi-channel series piezoelectric quartz crystal (S-MSPQC) cell sensor was constructed by square Au microelectrode in series connected with quartz crystal sensor in MSPQC. The experimental results showed square shape Au microelectrode was more sensitive than normally used interdigital microelectrode. New constructed S-MSPQC was successfully used for real time monitoring the injury of human umbilical vein endothelial cells which induced by lipopolysaccharide (LPS) and assessing the drug effects of two anti-oxidative vitamins, VC and VE and their combination against this injury. The detection results showed that the low concentration of LPS may promote the proliferation of the HUVEC cells at first 12h, then it caused the cell apoptosis. The pretreatment of VC or VE on the cells for 12h before adding the LPS could partially reduced the injury of LPS on HUVEC cells. The sensor detection results were all consisted with the results detected by MTT assay and microscopy observation. The synergistic effect of the combination of VC-VE on LPS-induced cell injury was also observed by sensor. Compared with the traditional biological methods, the proposed method is sensitive, label-free, non-invasive, cheap, simple, and automatic. It provides a new automatic tool for cell monitor in the field of cell biology, cytobiology, and drug effects research.

Multichannel series piezoelectric quartz crystal cell sensor for real time and quantitative monitoring of the living cell and assessment of cytotoxicity.

A new multichannel series piezoelectric quartz crystal (MSPQC) cell sensor for real time monitoring of living cells in vitro was reported in this paper. The constructed sensor was used successfully to monitor adhesion, spreading, proliferation, and apoptosis of MG63 osteosarcoma cells and investigate the effects of different concentrations of cobalt chloride on MG63 cells. Quantitative real time and dynamic cell analyses data were conducted using the MSPQC cell sensor. Compared with methods such as fluorescence staining and morphology observation by microscopy, the MSPQC cell sensor is noninvasive, label free, simple, cheap, and capable of online monitoring. It can automatically record the growth status of cells and quantitatively evaluate cell proliferation and the apoptotic response to drugs. It will be a valuable detection and analysis tool for the acquisition of cellular level information and is anticipated to have application in the field of cell biology research or cytotoxicity testing in the future.

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.

The construction and application of a molecular wire piezoelectric urease-producing bacteria sensor

The series piezoelectric quartz crystal (SPQC) sensor is widely used for detecting microorganisms. However, because of the slight corrosion of metal electrodes in ammonia-containing media, the SPQC is unsuitable for the detection of urease-producing bacteria. In this paper, a molecular wire piezoelectric urease-producing bacteria (MWPUB) sensor was proposed for rapid identification and quantification of urease-producing bacteria. A polyimide–polypyrrole composite film was used as an electrode in place of the original metal electrode in SPQC and connected to a piezoelectric quartz crystal in series in a self-made oscillator. The composite film could react with NH3, which caused a decrease of conductance and resulted in a change in oscillating frequency of the piezoelectric quartz crystal. When the MWPUB sensor was used to quantitatively determine urease-producing bacteria, the frequency detection time (FDT) obtained from the frequency shift curve had a linear relationship with the logarithm values of the initial concentration of urease-producing bacteria in the range of 8 to 3.2 × 108 colony forming units (cfu) per millilitre (mL). Compared with SPQC, the new method was sensitive, rapid and stable in culture media.

Multi-Channel Series Piezoelectric Quartz Crystal Sensor with Partial Least Square Method for Identification of Clinically Relevant Bacteria

Multi-Channel Series Piezoelectric Quartz Crystal Sensor with Partial Least Square Method for Identification of Clinically Relevant Bacteria

A New Sensor Method for Studying the Effect of Gentamicin and Cefotaxime Combination Against Escherichia coli

A new sensor method based on a multi-channel series piezoelectric quartz crystal (MSPQC) was proposed for studying the effect of gentamicin and cefotaxime combination against Escherichia coli ATCC 25922. The frequency curves under different combination regimens were obtained and compared with each other. When antibiotic had an inhibitory effect to the growth of bacteria, frequency detection time (FDT) would be prolonged. The FDT was used to assess the effect of an antibiotic combination. By using the proposed method, simultaneous administration, different order, and time interval of nonsimultaneous administration were investigated in detail. The MSPQC method can provide the process information in real time. It is simple, rapid, and easy to perform.

Novel Reduction Kinetics Model of Dimethoate (DMA) on the Growth of Pseudomonas aeruginosa

A new method for monitoring Pseudomonas aeruginosa growth with dimethoate (DMA) as sole carbon using the series piezoelectric quartz crystal (SPQC) and high-performance liquid chromatography (HPLC) was described. Compared with the general methods, SPQC gives real-time, multidimensional information. The determination limit of HPLC was 1.08 ng. A combined novel response model for Pseudomonas aeruginosa degrading DMA was derived. By fitting DMA reducing data, the value of the reduction rate constant (k) was obtained and in line with the actual trend. The proposed kinetic model was successfully applied to Pseudomonas aeruginosa degrading DMA.

New MSPQC Method for Rapid Identification and Quantification of Pseudomonas aeruginosa

A new method for the rapid identification and quantification of Pseudomonas aeruginosa using multichannel series piezoelectric quartz crystal (MSPQC) was proposed. The identification of P. aeruginosa was based on the development of acetamide broth, which can selective culture P. aeruginosa and performed perfectly in MSPQC. The quantitative detection of P. aeruginosa was based on the fact that the frequency detection time (FDT) detected by MSPQC in developed medium had a linear relationship with the logarithm of its initial concentration in the range of 10–108 colony − forming units (cfu) ml–1 (R=−0.984). The detection limit was 10 cfu ml–1.