Tag Archive for: QCMD

Publication on AWSensors technology

Exploiting the high affinity between cellulose nanofibrils and Aloe vera acemannan to develop elastic, crosslinker-free, all-polysaccharide hydrogels

Authors: Ngoc Huynh, Lukas Fliri, Juan José Valle-Delgado, Monika Österberg

Journal: International Journal of Biological Macromolecules

Abstract: Plant-based polymers hold promising prospects thanks to their bioactivity, diversity and versatility but they are currently overshadowed by synthetic and animal-derived materials, especially in biomedical applications. In this study, we developed an entirely plant-based hydrogel with improved mechanical performance based on TEMPO-oxidized cellulose nanofibrils (TCNFs) and the polysaccharide fraction (AVPF) extracted from Aloe vera L. (Aloe barbadensis Miller). The hydrogel blends exhibited excellent viscoelastic properties, minimal shrinkage and a significant increase in compressive modulus (ranging from 2.7 to 13.2 kPa versus 0.8 kPa in single component hydrogels), suggesting a synergistic effect. In-depth analysis of interaction and morphology of the hydrogels by QCM-D, AFM and SEM imaging showed that the observed synergy was the result of the complementary action between the two components and a uniform spatial distribution of the two networks. TCNFs built the rigid skeleton for the hydrogels, while AVPF physically adsorbed on TCNFs, forming a flexible matrix, allowing for better load transfer and dissipation in both static and dynamic loading, leading to a remarkable increase in moduli that surpassed the mere sum of the two individual components. In addition, the obtained hydrogels also showed little to no perceptible shrinkage after drying, unlike the single-component hydrogels made from the initial materials. These hydrogels offer a sustainable and ethical alternative to animal-derived materials, with great potential in biomedical fields.

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Publication on AWSensors technology

Thermomechanical Characterization of High Tg Disulfide-Containing Thermoplastic Polyimides

Authors: Margaret A. Hall, Broderick Lewis, Kenneth R. Shull

Journal: Macromolecules

Abstract: Covalent adaptable networks are frequently studied as alternatives to conventional thermosetting polymers because they can be recycled and reprocessed; however, the inclusion of dynamic covalent bonds within high-temperature (or high-performance) engineering thermoplastics remains largely unexplored. In this work, dynamic disulfide-containing thermoplastic polyimides were synthesized and compared to nondynamic thermoplastic polyimides. The thermomechanical properties of these polymers were examined by utilizing several techniques, including thermogravimetric analysis, differential scanning calorimetry, along with the use of the rheometric quartz crystal microbalance, and traditional dynamic mechanical analysis. The resulting experimental data suggest that the thermal stability of the dynamic compositions was slightly reduced in comparison to the nondynamic analogs, but the dynamic compositions exhibit a similar mechanical response under service conditions. The dynamic compositions also demonstrated significantly easier reprocessability via compression molding than their nondynamic counterparts.

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Publication on AWSensors technology

Matrix Metalloproteinase-9 Mediates Endothelial Glycocalyx Degradation and Correlates with Severity of Hemorrhagic Fever with Renal Syndrome

Authors: Chloé Jacquet. Rasmus Gustafsson, Ankit Kumar Patel, Magnus Hansson, Gregory Rankin, Fouzia Bano, Julia Wigren Byström, Anders Blomberg, Johan Rasmuson, Simon Satchell, Therese Thunberg, Clas Ahlm, Marta Bally, Anne-Marie Fors Connolly

Journal: medRxiv Preprint

Abstract: Hemorrhagic fever with renal syndrome (HFRS) caused by Puumala virus (PUUV) leads to vascular dysfunction contributing to acute kidney injury and pulmonary complications. The endothelial glycocalyx (eGLX) is crucial for vascular integrity, and its degradation may exacerbate disease severity. In this study, we examined the association between eGLX degradation and renal and pulmonary dysfunction in 44 patients with laboratory-confirmed PUUV infection. We measured plasma levels of eGLX degradation markers—syndecan-1, heparan sulfate, soluble thrombomodulin, and albumin— and found that these correlated with severe acute kidney injury and the need for oxygen therapy. In vitro experiments showed that matrix metalloproteinase-9 (MMP-9) and heparanase can degrade eGLX components, but albumin at physiological concentrations can mitigate this degradation and protect endothelial barrier function. These findings indicate that eGLX degradation contributes to HFRS pathogenesis and suggest that targeting the eGLX could be a therapeutic strategy to improve patient outcomes.

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Publication on AWSensors technology

The role of humidity in enhancing CO2 capture efficiency in polyethyleneimine thin films

Authors: John R. Hoffman, Avery E. Baumann, Christopher M. Stafford

Journal: Chemical Engineering Journal

Abstract: Amine impregnated sorbents have been extensively studied for direct air capture (DAC) of CO2 in both dry and humid conditions. In a dry environment, CO2 capture follows a carbamate formation mechanism. Amine efficiency can be improved by allowing more amine sites to participate in the reaction. Introducing water vapor helps break up internal hydrogen bonding within the amine-based polymer, which increases both the polymer mobility and accessibility of amine sites. In this work, we evaluate the influence of humidity on the CO2 capture in polyethyleneimine (PEI) thin films using tandem quartz crystal microbalance (QCM) and polarization modulation infrared reflection–absorption spectroscopy (PM-IRRAS). We show that tandem QCM/PM-IRRAS enables more accurate CO2 uptake measurements, as the combined techniques can separate individual mass changes due to CO2 and H2O sorption. CO2 adsorption capacity and amine efficiency were evaluated for a 10 nm and 100 nm film at varied temperatures, humidities, and CO2 concentrations. We find that water sorption greatly enhances CO2 uptake when the capture is limited by diffusional resistance (at higher CO2 concentration and in 100 nm films) but has less influence in conditions where CO2 availability is limiting uptake (at lower CO2 concentration and in 10 nm films). Thus, we argue that humidity does improve capture, but not at all conditions. Our approach enhances the understanding of H2O-assisted sorption of CO2 in PEI across a range of conditions while also presenting a measurement strategy to apply to, and hopefully optimize, component uptake in materials of interest to the CO2 capture community.

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Scientific publication

Silk Sericin/Chitosan Supramolecular Multilayered Thin Films as Sustainable Cytocompatible Nanobiomaterials

Authors: Miguel Rosas, Cristiana F. V. Sousa, Ana Pereira, Adérito J. R. Amaral, Tamagno Pesqueira, Sónia G. Patrício, Sara Fateixa, Helena I. S. Nogueira, João F. Mano, Ana L. Oliveira, and João Borges

Journal: Biomacromolecules

Abstract: Silk sericin (SS) has been widely discarded as a waste by the silk textile industry during the degumming process to obtain fibroin. However, in the past decade, an in-depth understanding of its properties and functions turned it into a high added-value biomaterial for biomedical applications. Herein, we report the molecular design and development of sustainable supramolecular multilayered nanobiomaterials encompassing SS and oppositely charged chitosan (CHT) through a combination of self-assembly and electrostatically driven layer-by-layer (LbL) assembly technology. The successful buildup of SS/CHT multilayered nanobiomaterials was demonstrated by the quartz crystal microbalance with dissipation monitoring and attenuated total reflectance-Fourier transform infrared spectroscopy, and the nanofilms’ wettable properties and nanofibrillar-like topography were shown by water contact angle, atomic force microscopy, and scanning electron microscopy. In vitro assays demonstrated the cytocompatibility of the LbL nanofilms toward human primary dermal fibroblasts, holding great promise as biofunctional nanocoatings for drug/therapeutics/cell delivery, tissue engineering, and regenerative medicine.

 

 

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Publication on AWSensors technology

Site-specific sulfations regulate the physicochemical properties of papillomavirus–heparan sulfate interactions for entry

Authors: Fouzia Bano, Laura Soria-Martinez, Dominik van Bodegraven, Konrad Throsteinsson, Anna M. Brown, Ines Fels, Nicole L. Snyder, Marta Bally, Mario Schelhaas

Journal: Science Advances

Abstract: Certain human papillomaviruses (HPVs) are etiological agents for several anogenital and oropharyngeal cancers. During initial infection, HPV16, the most prevalent cancer-causing type, specifically interacts with heparan sulfates (HSs), not only enabling initial cell attachment but also triggering a crucial conformational change in viral capsids termed structural activation. It is unknown, whether these HPV16-HS interactions depend on HS sulfation patterns. Thus, we probed potential roles of HS sulfations using cell-based functional and physicochemical assays, including single-molecule force spectroscopy. Our results demonstrate that N-sulfation of HS is crucial for virus binding and structural activation by providing high-affinity sites, and that additional 6O-sulfation is required to mechanically stabilize the interaction, whereas 2O-sulfation and 3O-sulfation are mostly dispensable. Together, our findings identify the contribution of HS sulfation patterns to HPV16 binding and structural activation and reveal how distinct sulfation groups of HS synergize to facilitate HPV16 entry, which, in turn, likely influences the tropism of HPVs.

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Publication on AWSensors technology

Quartz crystal microbalance with dissipation monitoring for studying soft matter at interfaces

Authors: Diethelm Johannsmann & Ilya Reviakine

Journal: Nature Reviews Methods Primers

Abstract: Quartz crystal microbalance with dissipation monitoring (QCM-D) probes interfaces by subjecting them to a periodic shear stress exerted by an acoustic resonator. The changes in the resonance frequency, Δf, and the half-width at half-maximum of the resonance, ΔΓ (closely related to the changes in the dissipation, ΔD), measured with the QCM-D are proportional to the in-phase and out-of-phase components of the area-averaged transverse stress at the resonator surface, respectively. Amounts, organization and properties of soft matter at an interface between the resonator and a liquid or a gas are derived from the measurements of Δf and ΔΓ on multiple overtones at megahertz frequencies. The properties include viscoelasticity and stress relaxation dynamics on the timescale of the oscillation period. This Primer offers guidelines on instrument design, experimental procedures and data analysis for interpreting frequency and bandwidth changes in terms of structure and dynamics of the sample. There is a focus on recent progress in the analysis of the acoustic ratio, ΔΓ/(−Δf), and numerical methods of modelling. Limitations of the existing approaches for data analysis are discussed. Challenges and possible future developments are formulated in an outlook.

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Scientific publication

Demonstrating a Quartz Crystal Microbalance with Dissipation (QCMD) to Enhance the Monitoring and Mechanistic Understanding of Iron Carbonate Crystalline Films

Authors: Igor Efimov, Eftychios Hadjittofis, Mustafa M. Alsalem, and Kyra L. Sedransk Campbell

Journal: Langmuir

Abstract:

This paper reports the real time monitoring of siderite deposition, on both Au- and Fe-coated surfaces, using the changes in frequency and dissipation of quartz crystal microbalance with dissipation (QCMD). In an iron chloride solution saturated with carbon dioxide, buffered with sodium bicarbonate to pH 6.8, roughly spherical particles of siderite formed within 15 min, which subsequently deposited on the QCMD crystal surface. Imaging of the surface showed a layer formed from particles ca. < 0.5 μm in diameter. Larger particles are clearly deposited on top of the lower layer; these larger particles are >1 μm in diameter. Monitoring of the frequency clearly differentiates the formation of the lower layer from the larger crystals deposited on top at later times. The elastic moduli calculated from QCMD data showed a progressive dissipation increase; the modeling of the solid–liquid interface using a flat approximation resulted in a poor estimation of elastic and storage moduli. Rather, the impedance modeled as a viscoelastic layer in contact with a semi-infinite liquid, where a random bumpy surface with a Gaussian correlator is used, is much more accurate in determining the elastic and storage moduli as losses from the uneven interface are considered. A further step considers that the film is in fact a composite consisting of hard spherical particles of siderite with water in the vacant spaces. This is treated by considering the individual contributions of the phases to the losses measured, thereby further improving the accuracy of the description of the film and the QCMD data. Collectively, this work presents a new framework for the use of QCMD, paired with traditional approaches, to enhance the understanding of crystal deposition and film formation as well as quantify the often evolving mechanical properties.

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Scientific publication

A low-cost microfluidic flow stabilizer for enhancing QCM measurement stability in in-liquid bio-applications

Authors: Mohamed Adel, Ahmed Allam, Ashraf E Sayour, Hani F Ragai, Shinjiro Umezu and Ahmed M R Fath El-Bab

Journal: Eng. Res. Express

Abstract

Quartz crystal microbalance (QCM) is a powerful sensing technique widely used in various applications, including biosensing, chemical analysis, and material science. In in-liquid applications, QCM measurements are susceptible to fluctuations in fluid flow rate, which can introduce unwanted noise and compromise the accuracy and reliability of the measurements. In this work, we present an approach to enhance the stability of QCM measurements by utilizing a microfluidic flow stabilizer. The flow stabilizer is designed to minimize flow rate fluctuations, thereby reducing the impact of hydrodynamic effects on the QCM frequency response. We employ a comprehensive methodology that combines computational fluid dynamics (CFD) simulations using ANSYS Fluent software, microfabrication, and experimental testing to evaluate the effectiveness of the flow stabilizer in mitigating flow-induced fluctuations and improving the reliability of QCM measurements. For fabrication, we use direct engraving with a CO2 laser beam on polymethyl methacrylate (PMMA) material to drastically reduce the fabrication cost (to <40 cents) and fabrication time (to 35 min) of the microfluidic chip. Two different designs have been presented and tested: one with a single air reservoir and the other with two reservoirs. Two distinct setups employing a peristaltic pump and a micropump, along with a high fundamental frequency of 50 MHz QCM sensor, were utilized for comprehensive testing in this study. The experimental results demonstrated that the first and second designs of the microfluidic flow stabilizer effectively reduced the fluctuation amplitude in QCM measurements from 100% (input) to 23% and 19% (output), respectively.

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Scientific publication

Real-time monitoring of dephosphorylation process of phosphopeptide and rapid assay of PTP1B activity based on a 100 MHz QCM biosensing platform

Authors: Shuping Liu, Qingqing Zhang, Xiaohua Zhang, Cuicui Du, Jinhua Chen, Shihui Si

Journal: Talanta

Abstract

The misregulation of protein phosphatases is a key factor in the development of many human diseases, notably cancers. Here, based on a 100 MHz quartz crystal microbalance (QCM) biosensing platform, the dephosphorylation process of phosphopeptide (P-peptide) caused by protein tyrosine phosphatase 1B (PTP1B) was monitored in real time for the first time and PTP1B activity was assayed rapidly and sensitively. The QCM chip, coated with a gold (Au) film, was used to immobilized thiol-labeled single-stranded 5′-phosphate-DNAs (P-DNA) through Au–S bond. The P-peptide, specific to PTP1B, was then connected to the P-DNA via chelation between Zr4+ and phosphate groups. When PTP1B was injected into the QCM flow cell where the P-peptide/Zr4+/MCH/P-DNA/Au chip was placed, the P-peptide was dephosphorylated and released from the Au chip surface, resulting in an increase in the frequency of the QCM Au chip. This allowed the real-time monitoring of the P-peptide dephosphorylation process and sensitive detection of PTP1B activity within 6 min with a linear detection range of 0.01–100 pM and a detection limit of 0.008 pM. In addition, the maximum inhibitory ratios of inhibitors were evaluated using this proposed 100 MHz QCM biosensor. The developed 100 MHz QCM biosensing platform shows immense potential for early diagnosis of diseases related to protein phosphatases and the development of drugs targeting protein phosphatases.

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