Shear Mode Acoustic Wave Sensor Research Articles

Measurement of Phase Changes in Live Crude Oil Using an Acoustic Wave Sensor: Asphaltene Instability Envelope

An experimental method is proposed for determining the asphaltene instability envelope of a crude oil or crude oil + antisolvent system under reservoir conditions by using a thickness shear mode acoustic wave sensor fully immersed in oil under pressure. The technique allows determining the upper asphaltene instability pressure by carrying out constant mass expansion experiments, whereas the lower asphaltene instability pressure can be determined during constant mass compression tests. The basis of the technique is presented, and measurements have been carried out in a bottomhole oil + CO2 system with various CO2 contents at reservoir temperature. Finally, the effect of temperature on the asphaltene instability envelope was studied on two systems with 45 and 55 mol % CO2.

Label-free methods for probing the interaction of clioquinol with amyloid-β

The presence of amyloid-β (Aβ) fibrils is characteristic of Alzheimer's disease (AD), and the aggregation of these amyloidogenic proteins is a nucleation-dependent process. In this report, label-free methods based on surface plasmon resonance (SPR) and thickness shear mode acoustic wave sensors (TSM-AWS) were used to detect monomer elongation in real-time. The modulation of Aβ aggregation using a well-described flavonoid, clioquinol (CQ) was also observed. Established methods like fluorescence and electrochemistry were also employed to confirm the interaction of CQ with Aβ. Good correlation between the designed label-free methods creates a promising platform for the screening of novel amyloid inhibitors.

Synchronization of the circadian rhythm generator and the effects of glucagon on hypothalamic mouse neurons detected by acoustic wave propagation

A thickness shear mode acoustic wave sensor has been used to study the reaction of clonal, immortalized hypothalamic murine neurons in response to glucagon and serum shock in a label free, continuous and real time manner under physiological conditions. Two cell lines were examined; these were the mHypoE-38s and the mHypoE-46s. The technique possesses sufficient sensitivity to detect minor neuronal changes and is capable of discerning subtle differences in cellular behaviors under both stimuli. The kinetics and magnitude of the changes observed here are significantly different compared to those instigated upon causing depolarization, cytoskeletal modifications and surface-adhesion specific interaction alterations with the same cells. Interestingly, this technique has the sensitivity and capability of observing all such changes at the neuronal level without the necessity for invasive interrogation. Under the influence of glucagon, the neurons display both short- and long-term changes, in particular the resonant frequency shifts by -23 ± 8 Hz (n = 13, std. dev.) and the motional resistance decays at a rate of approximately 10 Ω h(-1) over a 2 hour interval. The effect of synchronizing the neurons prior to glucagon stimulation did not influence the cellular changes observed. The process of partial and full synchronization of the cells resulted in different responses. For full synchronization, the addition of the serum bolus triggered resonant frequency and motional resistance shifts of +75 Hz and +18.5 Ω respectively, which decayed back to baseline levels after 30 minutes. The duration of this decay closely matched the time required for full synchronization in a separate study. The changes observed for partial synchronization were significantly different from full synchronization as the baseline levels in both resonant frequency and motional resistance were not re-achieved indicative of the cell-sensor system detecting the difference between full and partial synchronization. Preliminary qualitative immunocytochemistry and RT-PCR studies on these cells support the results obtained with the TSM sensor for the glucagon receptor study.

Thickness shear mode acoustic wave sensors for characterizing the viscoelastic properties of cell monolayer

The thickness shear mode (TSM) quartz crystal resonator attached with living cells has been shown to be an effective functional biosensing device to monitor the process of cell adhesion to a surface in real time. In this study, a multilayer acoustic wave sensor model including a quartz resonator substrate, a cell-substrate interfacial layer and a cell layer has been developed based on the state of cell adhesion to the quartz resonator substrate. In order to obtain comprehensive and detailed information on the resonator oscillation, the electrical admittance spectrum of the resonator sensor over a range of frequencies near resonance is measured by an impedance analyzer instead of only measuring the resonance frequency and motional resistance with an oscillator circuit. After cells are fully spread to form a monolayer on the surface, the admittance spectrum of the multilayer loaded acoustic wave sensor was recorded and used to extract the viscoelastic properties of the cell layer by fitting experimental spectrum curve with those obtained from the theoretical model through a curve-fitting algorithm. It is found that the viscoelastic properties of the cell layer are consistent with those measured by other techniques, indicating the quartz acoustic wave sensor can be used as a non-invasive device for characterizing the mechanical properties of cell layers.

Monitoring cell adhesion by using thickness shear mode acoustic wave sensors

The thickness shear mode (TSM) acoustic wave sensor attached with living cells has been shown to be an effective functional biosensing device to monitor the process of cell adhesion to a surface in real time. In this study, a multilayer sensor model that includes a quartz substrate, a cell–substrate interfacial layer and a cell layer was constructed based on the state of cell adhesion to the substrate. The dynamic process of cell adhesions as a function of cell seeding densities was monitored using the acoustic wave sensor. The mechanisms that are responsible for the frequency and resistance change are discussed according to the predictions of the acoustic wave sensor model. In addition, knowing that the actin cytoskeleton is important for cell adhesion, we investigated the motional resistance change caused by the disruption of actin cytoskeleton induced by fungal toxin cytochalasin D in the human skin fibroblasts. The results indicate that resistance changes are related to the disruption of actin cytoskeleton and dosage-dependent.

Analytical advantages of monitoring a particular characteristic frequency in a thickness shear mode acoustic wave sensor

The oscillator or active method, where just the series resonance frequency ( f s) can be measured, has been the method of choice for analytical applications of bulk acoustic wave sensors. However, the present work shows that an increase in the analytical signal can be obtained if the frequency at minimum impedance ( f n ) is measured. An example is given, where quantitative analysis is only possible if f n is measured instead of f s. Sensitivity of a particular analysis can be improved if a previous study is performed in order to select the most suitable characteristic frequency ( f s, f n or f p) to be monitored.

Kinetics of hybridization of interfacial RNA homopolymer studied by thickness-shear mode acoustic wave sensor

The impedance response of RNA homopolymer hybridization on the electrode-solution interface of thickness shear mode acoustic wave sensors has been examined on a real-time basis by network analysis. The effects of blocking agents conventionally used to avoid nonspecific adsorption, solution ionic strength and temperature on the rate of interfacial hybridization have been examined quantitatively in terms of a pseudo-first order effective rate constant. A hybridization mechanism involving transport of RNA probe molecules in solution followed by duplex formation is proposed. The results suggest that the use of blocking agents is not necessary and that the biosensor is capable of the direct detection of hybridization in the present of nonspecific adsorption.

Multiple chemical information from the thickness shear mode acoustic wave sensor in the liquid phase

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultiple chemical information from the thickness shear mode acoustic wave sensor in the liquid phaseMengsu. Yang and Michael. ThompsonCite this: Anal. Chem. 1993, 65, 9, 1158–1168Publication Date (Print):May 1, 1993Publication History Published online1 May 2002Published inissue 1 May 1993https://doi.org/10.1021/ac00057a010RIGHTS & PERMISSIONSArticle Views389Altmetric-Citations122LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Four-layer theory for the acoustic shear wave sensor in liquids incorporating interfacial slip and liquid structure

A theory is developed which describes the behavior of thickness shear mode acoustic wave sensors in liquids. The linear theory for piezoelectricity is coupled to a treatment which describes interfacial viscosity in terms of an activation energy barrier to interfacial flow.