Series Piezoelectric Quartz Crystal Sensor Research Articles

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 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.

Novel phage-piezoelectric sensor for rapid drug susceptibility testing of Mycobacterium tuberculosis

Novel phage-piezoelectric sensor was constructed for rapid drug susceptibility testing based on the proposed method of phage amplified multichannel series piezoelectric quartz crystal sensor (PA-MSPQC) for the detection of Mycobacterium tuberculosis and criterion of resistant strains by CLSI. Under the condition of anti-TB drugs, the resistant M. tuberculosis survived, but the sensitive strains can be killed. According to the criterion of resistant strains by CLSI, the 105cfu of strains with frequency shift less than 121Hz were resistant to rifampin, isoniazid and ethambutol, 92Hz to streptomycin. The sensitivity and specificity of 557 strains drug susceptibility test by proposed methods are 91% and 93%, respectively, compared with the mycobacteria growth indicator tube (MGIT) method. But the turnaround time of proposed method is no more than 35h, far less than that of MGIT 960 methods. It will find application in clinical test.

Novel Phage Amplified Multichannel Series Piezoelectric Quartz Crystal Sensor for Rapid and Sensitive Detection of Mycobacterium tuberculosis

The key factors that control the spread and mortality rate of tuberculosis (TB) are rapid detection and diagnosis. However, the current detection of Mycobacterium tuberculosis (M. tuberculosis) cannot meet the recommended requirements for clinical diagnosis in turnaround time. In this paper, the feature of phage D29 that infects M. tuberculosis and Mycobacterium smegmatis (M. smegmatis) was combined with the sensitivity of multichannel series piezoelectric quartz crystal sensor (MSPQC) to detect M. tuberculosis. The phage D29 played a role of inhibiting the growth of M. tuberculosis and M. smegmatis. M. tuberculosis is used to protect phage D29 from being killed by ferrous ammonium sulfate (FAS) and carries phage D29 into the detection medium containing M. smegmatis. The action of M. smegmatis indicated the existence state of phage D29 in the detection medium. The growth curve of M. smegmatis obtained by MSPQC indicated the state of the growth of M. tuberculosis. Therefore, M. tuberculosis in the sample could be rapidly detected by evaluating the extent of inhibiting the growth of M. smegmatis compared with the normal growth of M. smegmatis. The detection of M. tuberculosis was transformed into the detection of M. smegmatis, which is more rapid and sensitive than that of M. tuberculosis. For 10(2) cfu/mL of M. tuberculosis in clinical sample, the turnaround time was less than 30 h. Although statistical analysis showed that no significant difference existed between the results of the proposed method here and the BACTEC960 MGIT method in clinical M. tuberculosis detection, the phage amplified MSPQC (PA MSPQC) method presented here was faster and more economical.

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

The study and application of a new IDE–PQC sensor

A new interdigital electrode–piezoelectric quartz crystal (IDE–PQC) sensor was proposed here. It was constructed using an interdigital electrode (IDE) and a piezoelectric quartz crystal in series. The response was studied theoretically and experimentally. Proposed sensor was more sensitive than series piezoelectric quartz crystal sensor (SPQC) to changes in electrical parameters of solution in certain conditions. Factors affecting the response of the IDE–PQC were discussed in detail. Proposed method was used to detect Pseudomonas aeruginosa. The logarithm of the initial concentration of P. aeruginosa had a linear relationship with frequency detection time (FDT) in the range of 10–10 6 cfu ml −1. The detection limit could be as low as 10 cfu ml −1. Pour plate counts (PPC) and SPQC methods were used for comparing with proposed method. Escherichia coli and Staphylococcus aureus were also detected successfully with proposed method.

Interaction process between ionic surfactant and protein probed by series piezoelectric quartz crystal technique

A method for probing the interaction process between ionic surfactant and protein was developed with series piezoelectric quartz crystal (SPQC) sensing technique. It was based on the sensitive response of the SPQC sensor to the change in solution conductivity. A new relationship between the sensor response and the properties of ionic species in solution was derived. The method was used to examine the interaction process of two surfactants, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), with lysozyme in aqueous solution. The obtained experimental results were in agreement with those of other methods from references. These results had been discussed. It was shown that the new method developed here was a useful and promising tool for probing the ionic surfactant–protein interaction process and might find more applications in similar studies.

A novel investigation of magnetic field effects on the sedimentation of erythrocytes with the series piezoelectric quartz crystal sensor

A series piezoelectric quartz crystal sensor was employed to monitor the sedimentation of erythrocytes outside or under a magnetic field. High sensitive frequency shifts were obtained in the range where the hematocrit was very small. The effects of magnetic fields on the sedimentation of erythrocytes containing deoxyhemoglobin or methemoglobin, or erythrocytes suspended in Dy[EDTA] − diluent were measured by the relative differential of frequency shifts. They were found to be markedly dependent upon the magnetic field strength and the paramagnetic susceptibility of erythrocytes, which could be predicted by the theoretical discussion.

Correlations of the impedance parameters and conductivity and permittivity of liquid and gel phases in a series piezoelectric quartz crystal sensor

The impedance characteristics of a series piezoelectric quartz crystal (SPQC) sensor were investigated using a network/impedance analyzer. The correlations between the impedance parameters, including the magnitude and phase of the impedance and the resonant frequencies, and the conductivity and/or the permittivity of the test solutions were derived theoretically and in good agreement with the experimental results. It was shown that the value of the series frequency ( f s) decreases with increasing conductivity and permittivity of the liquid. The parallel frequency ( f p) is the constant. The values of the maximum impedance (| Z| max) and corresponding frequency ( f max,), are not related to the conductivity and permittivity of the liquid. The value of the minimum impedance (| Z| min) decreases with increasing permittivity and has a maximum in a solution of middle conductivity. The corresponding frequency ( f min) has the same value as the f s. The maximum phase of the impedance ( θ max) increases slightly with increasing permittivity and has a minimum in electrolyte solution of middle conductivity. In the impedance–frequency curves, there is an iso-impedance point for the SPQC in electrolyte solutions. The SPQC method was applied to monitor the process of hydrogel formation.

A new method based on gelation of tachypleus amebocyte lysate for detection of Escherichia coliform using a series piezoelectric quartz crystal sensor

A new method utilizing a series piezoelectric quartz crystal (SPQC) sensor was used to monitor the gelation of Tachypleus amebocyte lysate (TAL) and this reaction was applied to determine the Escherichia coliform ( E. coli). The technique depended on the change of conductivity and permittivity during the course of gelation. This method was rapid and sensitive. Some factors affecting the determination were discussed. Results showed that the frequency shift was linearly related to the logarithm of E. coli concentration in the range of 2.1×10 4–2.1×10 8 cells/ml. The correlation coefficient is 0.993. This SPQC-TAL method was compared with the standard pour plate counts (PPCs). The proposed method for detection of E. coli is much faster and simpler than the traditional methods.

A new piezoelectric response model for population growth of bacteria

A piezoelectric response model on the population growth of microorganism is proposed. This model is based on a novel population growth model, which has a more obvious ecological meaning and the fact that the series piezoelectric quartz crystal (SPQC) sensor responses to conductivity changes of the medium during the growth of the microorganism. From the response model four parameters can be obtained including the maximum specific growth rate μ m, saturated population size N m, and two constants C and K 1. The influence of the parameters on the response curve is discussed in which the influences of μ m and N m are more obvious. With the proposed model the quantitative determination of bacteria may be more accurate than the frequency detection time (FDT) method. Then the growth of Escherichia coliform ( E. coli) monitored with a SPQC sensor is compared with the simulated growth curve obtained by the proposed model and a good agreement is obtained.

A rapid method for determination of Staphylococcus aureus based on milk coagulation by using a series piezoelectric quartz crystal sensor

A series piezoelectric quartz crystal (SPQC) sensor was utilized to determine the number of bacteria based on the coagulation of milk in which Staphylococcus aureus ( S. aureus) had grown. Compared with the method based on a PQC coated with a thin film, earlier it had the advantage that no dilution of the medium was needed and cease of the oscillation can be avoided throughout the experiment. Moreover, it was rapid, the turning-point time (TT) for quantitative detection which was the time at which the frequency begins to return after a drop in response curve was easy to determine and there was a good relation between TT and logarithm of the initial concentration of S. aureus in the range of 2.4×10 2–2.4×10 5 cells ml −1.