A Review of Quartz Crystal Microbalance for Chemical and Biological Sensing Applications

Ridge gap waveguide is one of the new technologies in the field of waveguides. Their advantages include being planar, low cost of construction, shielding by metal without the need for problems related to packaging, the formation of a narrow gap enclosed between two metal plates, realization of the texture on one of the metal plates and lower losses. These structures have no mechanical connection. While electric currents must flow in them. In this article, two graphene-based ridge gap waveguide coupler structures are presented. The designed structures are used in the THz band. By using graphene in the THz frequency band, frequency reconfigurable can be achieved. S-parameters curves, phase difference diagrams and e-field distributions are reported for two graphene-based ridge gap waveguide couplers.

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“…While (-e) shows electron charge. Fermi-Dirac distribution is presented like this [51][52][53][54][55][56][57][58][59][60][61]:…”

Section: Graphene Conductivitymentioning

confidence: 99%

Implementation of a Graphene-Based RGW Coupler for THz Applications

Kiani

Hamedani

Rezaei

2023

Preprint

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“…There are several studies on the detection of multiple targets using this technology [162][163][164]. While this technology, using coatings and surface modifiers in the form of functional nanoparticles, polymers, and complexes, has been widely explored [165], its development in GMO detection has been slow in recent years, possibly because of its delicate and complicated production process.…”

Section: Other Types Of Sensorsmentioning

confidence: 99%

Research Progress of Nucleic Acid Detection Technology for Genetically Modified Maize

Luo,

Li,

Wang

et al. 2023

IJMS

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Genetically modified (GM) maize is one of the earliest GM crops to have achieved large-scale commercial cultivation globally, and it is of great significance to excel in the development and implementation of safety policy regarding GM, and in its technical oversight. This article describes the general situation regarding genetically modified maize, including its varieties, applications, relevant laws and regulations, and so on. From a technical point of view, we summarize and critically analyze the existing methods for detecting nucleic acid levels in genetically modified maize. The nucleic acid extraction technology used for maize is explained, and the introduction of traditional detection techniques, which cover variable-temperature and isothermal amplification detection technology and gene chip technology, applications in maize are described. Moreover, new technologies are proposed, with special attention paid to nucleic acid detection methods using sensors. Finally, we review the current limitations and challenges of GM maize nucleic acid testing and share our vision for the future direction of this field.

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“…Thus, a QCM transducer coated with a specific receptor is able to detect frequency shifts associated with receptor–analyte interaction and analyte recognition . In many cases, molecularly imprinted polymers, artificial materials that generate surface modifications, have been used as an alternative to antibody’s or antigen’s recognition layer. , …”

Section: Introductionmentioning

confidence: 99%

Quantification of Enzymatic Biofilm Removal Using the Sauerbrey Equation: Application to the Case of Pseudomonas protegens

Levy,

Salustro,

Battaglini

et al. 2024

ACS Omega

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A methodology for the quantitative analysis of enzymatic removal of biofilms (BF) was developed, based on a quartz crystal microbalance (QCM) under stationary conditions. This was applied to the case of Pseudomonas protegens (PP) BFs, through a series of five enzymes, whose removal activity was screened using the presented methodology. The procedure is based on the following: when BFs can be modeled as rigid materials, QCM can be used as a balance under stationary conditions for determining the BFs mass reduction by enzymatic removal. For considering a BF as a rigid model, energy dissipation effects, associated with viscoelastic properties of the BF, must be negligible. Hence, a QCM system with detection of dissipation (referred to as QCM with dissipation) was used for evaluating the energy losses, which, in fact, resulted in negligible energy losses in the case of dehydrated PP BFs, validating the application of the Sauerbrey equation for the change of mass calculations. The stationary methodology reduces operating times and simplifies data analysis in comparison to dynamic approaches based on flow setups, which requires the incorporation of dissipation effects due to the liquid media. By carrying out QCM, glycosidase-type enzymes showed BF removal higher than 80% at enzyme concentration 50 ppm, reaching removal over 90% in the cases of amylase and cellulase/xylanase enzymes. The highest removal percentage produced a reduction from about 15 to 1 μg in the BF mass. Amylase enzyme was tested from below 50 to 1 ppm, reaching around 60% of removal at 1 ppm. The obtained results were supported by other instrumental techniques such as Raman spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, atomic force microscopy, high performance anion exchange chromatography, thermogravimetric analysis, and differential scanning calorimetry. The removal quantifications obtained with QCM were compared with those obtained by well-established screening techniques (UV−vis spectrophotometry using crystal violet and agar diffusion test). The proposed methodology expands the possibility of using a quartz microbalance to perform enzymatic activity screening.

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A Review of Quartz Crystal Microbalance for Chemical and Biological Sensing Applications

Cited by 40 publications

References 52 publications

Implementation of a Graphene-Based RGW Coupler for THz Applications

Implementation of a Graphene-Based RGW Coupler for THz Applications

Research Progress of Nucleic Acid Detection Technology for Genetically Modified Maize

Quantification of Enzymatic Biofilm Removal Using the Sauerbrey Equation: Application to the Case of Pseudomonas protegens

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