Solidified Liquid Layer Model Expands the Application Fields of Quartz Crystal Microbalance

Fu, Long; Chen, Yanyan; Ma, Hongwei

doi:10.1002/marc.201100878

Cited by 7 publications

(11 citation statements)

References 36 publications

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“…One of the challenges in using QCM-D in liquid media is how to separate the frequency changes contributed from changes in mass and viscoelasticity of the adsorbed layer because under such a condition, the traditional Sauerbrey equation cannot be used to determine the mass change. [28][29][30] According to previous studies based on the Voigt model, for QCM-D measurements in aqueous solution with both mass change and viscoelasticity change, the frequency change (DF) and dissipation change (DD) can be expressed by the following equation: 26…”

Section: Characterizationmentioning

confidence: 99%

“…eqn ( 5) is an obvious step farther from the results of the theoretical analysis on QCM-D using the Voigt model. 26 By this approach and by the constitution of the frequency and dissipation response of the elastic sample shown in Scheme 2, 29,30 the pure mass change and the viscoelastic response can be separated, with the mass change and the retardation time of the sample deduced by the analysis.…”

Section: Changes In Mass and Viscoelasticity Of Polyelectrolyte Brushesmentioning

confidence: 99%

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Swelling enhancement of polyelectrolyte brushes induced by external ions

et al. 2014

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It has been observed previously that when permanently charged polyelectrolyte brushes are exposed to an external salt solution, they shrink when the salt level is high enough. In this study, we observed an enhanced swelling process before the salt concentration reached that limit. We systematically investigated a few strong polyelectrolyte brush systems, including sodium polystyrene sulfonate (PSSNa), poly([2-(methacryloyloxy)ethyl] trimethylammonium chloride) (PMETAC) and potassium poly(3-sulfopropyl methacrylate) (PSPMA) with different molecular weights and grafting density using a combination of methods, including ellipsometry, quartz crystal microbalance with dissipation (QCM-D) and atomic force microscope (AFM). The swelling enhancement is expressed by the thickening of the brush layer at moderate salt concentrations, accompanied by the decrease of refractive index, the increase of the amount of solvent inside the brushes and an increase in retardation time. A scenario is proposed in which the counterions penetrate into the brushes driven by the external salt ions, they disrupt and break up the previously formed multiplets due to the dipole-dipole interaction by the ion-pairs on the polymer chain. This process results in the release of the bound segments and the stretching of the polymer chains.

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Section: Characterizationmentioning

confidence: 99%

Section: Changes In Mass and Viscoelasticity Of Polyelectrolyte Brushesmentioning

confidence: 99%

Swelling enhancement of polyelectrolyte brushes induced by external ions

et al. 2014

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“…Highly sensitive QCM is also used for the study of DNA-related enzyme reactions3132. Our group have engaged in QCM study for a long time and proposed a “solidified liquid layer” (SLL) model that made it feasible for quantitative analyzing of frequency change in liquid3334. We also developed a DNA methylation detection method base on QCM and applied to evaluate the effect of 5-aza-2′-deoxycytidine (decitabine), a methyltransferase inhibitor used in clinical treatment35.…”

mentioning

confidence: 99%

Trend of telomerase activity change during human iPSC self-renewal and differentiation revealed by a quartz crystal microbalance based assay

Zhou

Xin

et al. 2014

Sci Rep

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Telomerase plays an important role in governing the life span of cells for its capacity to extend telomeres. As high activity of telomerase has been found in stem cells and cancer cells specifically, various methods have been developed for the evaluation of telomerase activity. To overcome the time-consuming procedures and complicated manipulations of existing methods, we developed a novel method named Telomeric Repeat Elongation Assay based on Quartz crystal microbalance (TREAQ) to monitor telomerase activity during the self-renewal and differentiation of human induced pluripotent stem cells (hiPSCs). TREAQ results indicated hiPSCs possess invariable telomerase activity for 11 passages on Matrigel and a steady decline of telomerase activity when differentiated for different periods, which is confirmed with existing golden standard method. The pluripotency of hiPSCs during differentiation could be estimated through monitoring telomerase activity and compared with the expression levels of markers of pluripotency gene via quantitative real time PCR. Regular assessment for factors associated with pluripotency or stemness was expensive and requires excessive sample consuming, thus TREAQ could be a promising alternative technology for routine monitoring of telomerase activity and estimate the pluripotency of stem cells.

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“…QCM is an acoustic-based sensor that detects interfacial mass losses as frequency increases (Δ f > 0)1517. The polymer-coated chip was treated with HCl (pH 1.0) to mimic the environmental pH of acidophiles (Fig.…”

Section: Resultsmentioning

confidence: 99%

A proton shelter inspired by the sugar coating of acidophilic archaea

Wang

Cai

et al. 2012

Sci Rep

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The acidophilic archaeons are a group of single-celled microorganisms that flourish in hot acid springs (usually pH < 3) but maintain their internal pH near neutral. Although there is a lack of direct evidence, the abundance of sugar modifications on the cell surface has been suggested to provide the acidophiles with protection against proton invasion. In this study, a hydroxyl (OH)-rich polymer brush layer was prepared to mimic the OH-rich sugar coating. Using a novel pH-sensitive dithioacetal molecule as a probe, we studied the proton-resisting property and found that a 10-nm-thick polymer layer was able to raise the pH from 1.0 to > 5.0, indicating that the densely packed OH-rich layer is a proton shelter. As strong evidence for the role of sugar coatings as proton barriers, this biomimetic study provides insight into evolutionary biology, and the results also could be expanded for the development of biocompatible anti-acid materials.

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Solidified Liquid Layer Model Expands the Application Fields of Quartz Crystal Microbalance

Cited by 7 publications

References 36 publications

Swelling enhancement of polyelectrolyte brushes induced by external ions

Swelling enhancement of polyelectrolyte brushes induced by external ions

Trend of telomerase activity change during human iPSC self-renewal and differentiation revealed by a quartz crystal microbalance based assay

A proton shelter inspired by the sugar coating of acidophilic archaea

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