Authors: Ilya Reviakine
Journal: Biointephases (2024)
Abstract
Applications of quartz crystal microbalance with dissipation to studying soft and biological interfaces are reviewed. The focus is primarily on data analysis through viscoelastic modeling and a model-free approach focusing on the acoustic ratio. Current challenges and future research and development directions are discussed.
You may read the full paper here.
AWsensors Technology Note, video, and executable QCMD Data Analysis with PyQTM.
C60-based Multivalent Glycoporphyrins Inhibit SARS-CoV-2 Specific Interaction with the DC-SIGN Transmembrane Receptor
Authors: Jennifer Patino-Alonso, Justo Cabrera-González, Javier Merino, Gema Nieto-Ortiz, Fátima Lasala, Jouma Katati, Carlos H. Bezerra da Cruz, Ajay K. Monnappa, Pablo Mateos-Gil, Ángeles Canales, Iván López-Montero, Beatriz M. Illescas, Rafael Delgado, and Nazario Martín
Journal: Small (2023)
Abstract
Since WHO has declared the COVID-19 outbreak a global pandemic, nearly seven million deaths have been reported. This efficient spread of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is facilitated by the ability of the spike glycoprotein to bind multiple cell membrane receptors. Although ACE2 is identified as the main receptor for SARS-CoV-2, other receptors could play a role in viral entry. Among others, C-type lectins such as DC-SIGN are identified as efficient trans-receptor for SARS-CoV-2 infection, so the use of glycomimetics to inhibit the infection through the DC-SIGN blockade is an encouraging approach. In this regard, multivalent nanostructures based on glycosylated [60]fullerenes linked to a central porphyrin scaffold have been designed and tested against DC-SIGN-mediated SARS-CoV-2 infection. First results show an outstanding inhibition of the trans-infection up to 90%. In addition, a deeper understanding of nanostructure-receptor binding is achieved through microscopy techniques, high-resolution NMR experiments, Quartz Crystal Microbalance experiments, and molecular dynamic simulations.
You may read the full paper here.
C60-based Multivalent Glycoporphyrins Inhibit SARS-CoV-2 Specific Interaction with the DC-SIGN Transmembrane Receptor
Comparison of Thin-Film Capacitor Geometries for the Detection of Volatile Organic Compounds Using a ZIF-8 Affinity Layer
Authors: Aleksander Matavž, Margot F. K. Verstreken, Jorid Smets, Max L. Tietze, and Rob Ameloot
Journal: ACS Sensors (2023)
Abstract
Their chemical diversity, uniform pore sizes, and large internal surface areas make metal–organic frameworks (MOFs) highly suitable for volatile organic compound (VOC) adsorption. This work compares two geometries of capacitive VOC sensors that use the MOF material ZIF-8 as an affinity layer. When using a permeable top electrode (thickness < 25 nm), the metal–insulator–metal (MIM) sandwich configuration exhibits superior sensitivity, an improved detection limit, and a smaller footprint than the conventional interdigitated electrode layout. Moreover, the transduction of VOC adsorption in ZIF-8 via MIM capacitors is more sensitive to polar VOCs and provides better selectivity at high loadings than gravimetric and optical transductions.
You may read the full paper here.
Comparison of Thin-Film Capacitor Geometries for the Detection of Volatile Organic Compounds Using a ZIF-8 Affinity Layer
Fouling of Reverse Osmosis Membrane with Effluent Organic Matter: Componential Role of Hydrophobicity
Authors: Noa Stein, Revital Sharon-Gojman, Meagan S. Mauter, Roy Bernstein and Moshe Herzberg
Journal: ACS ES&T Water (2023)
Abstract
Organic matter dissolved in tertiary effluents (effluent organic matter, EfOM) is the predominant organic membrane foulant in tertiary wastewater reverse osmosis (RO) desalination, ultimately causing biofouling. The interrelated effects of EfOM fractions of different hydrophobicity and polarity on membrane performance were studied by (i) examining each fraction’s overall effect on membrane permeability; (ii) analyzing the intrinsic hydraulic resistance induced by each fraction; (iii) studying their adsorption on the active layer of an RO membrane using a quartz crystal microbalance with dissipation monitoring (QCM-D); (iv) assessing their “dry” molecular mass when adsorbed on polyamide using localized surface plasmon resonance (LSPR) sensing; (v) analyzing their hydrodynamic radii by dynamic light scattering (DLS); and (vi) characterization using excitation–emission matrix (EEM) analysis and parallel-factor (PARAFAC) modeling. Hydrophobic and transphilic neutral fractions (containing ∼12.5% total organic carbon) have the greatest effect on membrane flux reduction and the highest hydraulic resistance and adhere most strongly to polyamide surfaces, resulting in the highest adsorbed “dry” mass. Therefore, in terms of their effect on RO permeate flux reduction, these fractions are the most detrimental in the EfOM mix. EEM analysis and associated PARAFAC modeling indicate that the main components causing this effect are mixtures of protein-like compounds, together with humic-like substances. Novel LSPR-based analysis elucidated the role of the fractions most detrimental to membrane permeability through measurement of dry mass surface concentration on a polyamide mimetic sensor. This study provides valuable insights into the roles of different EfOM fractions in RO membrane fouling and enhances our understanding of fouling during tertiary wastewater desalination.
You may read the full paper here.
Fouling of Reverse Osmosis Membrane with Effluent Organic Matter: Componential Role of Hydrophobicity
Tuning the water interactions of cellulose nanofibril hydrogels using willow bark extract
Authors: Ngoc Huynh, Juan José Valle-Delgado, Wenwen Fang, Suvi Arola, Monika Österberg
Journal: Carbohydrate Polymers (2023)
Abstract
Cellulose nanofibrils (CNFs) are increasingly used as precursors for foams, films and composites, where water interactions are of great importance. In this study, we used willow bark extract (WBE), an underrated natural source of bioactive phenolic compounds, as a plant-based modifier for CNF hydrogels, without compromising their mechanical properties. We found that the introduction of WBE into both native, mechanically fibrillated CNFs and TEMPO-oxidized CNFs increased considerably the storage modulus of the hydrogels and reduced their swelling ratio in water up to 5–7 times. A detailed chemical analysis revealed that WBE is composed of several phenolic compounds in addition to potassium salts. Whereas the salt ions reduced the repulsion between fibrils and created denser CNF networks, the phenolic compounds – which adsorbed readily on the cellulose surfaces – played an important role in assisting the flowability of the hydrogels at high shear strains by reducing the flocculation tendency, often observed in pure and salt-containing CNFs, and contributed to the structural integrity of the CNF network in aqueous environment. Surprisingly, the willow bark extract exhibited hemolysis activity, which highlights the importance of more thorough investigations of biocompatibility of natural materials. WBE shows great potential for managing the water interactions of CNF-based products.
You may read the full paper here.
Tuning the water interactions of cellulose nanofibril hydrogels using willow bark extract
Trace Water Effects on Crystalline 1-Ethyl-3-methylimidazolium Acetate
Authors: Ashlee Aiello, John R. Hoffman, Anthony P. Kotula, Lucas Q. Flagg, Ruipeng Li, and Jeremiah W. Woodcock
Journal: J. Phys. Chem. B (2023)
Abstract
Spontaneous room-temperature crystallization of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) was observed upon removal of trace water. Sample purity was confirmed using analytical nuclear magnetic resonance spectroscopy to ensure that trace water or other contaminants did not produce this observation. Raman spectroscopy and simultaneous quartz crystal microbalance/infrared spectroscopy measurements were used to study molecular reorganization during crystallization and decrystallization using trace water in the form of atmospheric moisture. These experimental results were supplemented with density functional theory calculations that indicate imidazolium cation ring stacking and side chain clustering with an exclusive arrangement of the acetate anion in the cation ring plane upon water removal. Crystal structure formation was confirmed using two-dimensional wide-angle X-ray scattering. This natural crystallization is attributed to the removal of trace water over extended periods of time and calls attention to the molecular-level role of water in the structure of hygroscopic ionic liquid systems.
You may read the full paper here.
Trace Water Effects on Crystalline 1-Ethyl-3-methylimidazolium Acetate
Multispecies biofilms on reverse osmosis membrane dictate the function and characteristics of the bacterial communities rather than their structure
Authors: Noya Ran, Gil Sorek, Noa Stein, Revital Sharon-Gojman, Moshe Herzberg, and Osnat Gillor
Journal: Environmental Research (2023)
Abstract
The main reason for the deterioration of membrane operation during water purification processes is biofouling, which has therefore been extensively studied. Biofouling was shown to reduce membrane performance reflected by permeate flux decline, reduced selectivity, membrane biodegradation, and consequently, an increase in energy consumption. Studies of biofouling focused on the identification of the assembled microbial communities, the excretion of extracellular polymeric substances (EPS), and their combined role in reduced membrane performance and lifetime. However, the link between the structure and function of biofouling communities has not been elucidated to date. Here, we provide a novel insight, suggesting that bacterial functions rather than composition control biofouling traits on reverse osmosis (RO) membranes. We studied the potential activity of RO biofilms at metatranscriptome resolution, accompanied by the morphology and function of the biofouling layer over time, including microscopy and EPS composition, adhesion, and viscoelastic properties. To that end, we cultivated natural multispecies biofilms in RO membranes under treated wastewater flow and extracted RNA to study their taxonomies and gene expression profiles. Concomitantly, the biofilm structure was visualized using both scanning electron microscopy and laser scanning confocal microscopy. We also used quartz crystal microbalance with dissipation to characterize the affinity of EPS to membrane-mimetic sensors and evaluated the viscoelasticity of the Ex-Situ EPS layer formed on the sensor. Our results showed that different active bacterial taxa across five taxonomic classes were assembled on the RO membrane, while the composition shifted between 48 and 96 h. However, regardless of the composition, the maturation of the biofilm resulted in the expression of similar gene families tightly associated with the temporal kinetics of the EPS composition, adhesion, and viscoelasticity. Our findings highlight the temporal selection of specific microbial functions rather than composition, featuring the adhesion kinetics and viscoelastic properties of the RO biofilm.
You may read the full paper here.
Multispecies biofilms on reverse osmosis membrane dictate the function and characteristics of the bacterial communities rather than their structure
Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model
Authors: Diethelm Johannsmann, Arne Langhoff, Christian Leppin, Ilya Reviakine, and Anna M. C. Maan
Journal: Sensors (2023)
Abstract
Quartz crystal microbalance with dissipation monitoring (QCMD) is a well-established technique for studying soft films. It can provide gravimetric as well as nongravimetric information about a film, such as its thickness and mechanical properties. The interpretation of sets of overtone-normalized frequency shifts, Δf/n, and overtone-normalized shifts in half-bandwidth, ΔΓ/n, provided by QCMD relies on a model that, in general, contains five independent parameters that are needed to describe film thickness and frequency-dependent viscoelastic properties. Here, we examine how noise inherent in experimental data affects the determination of these parameters. There are certain conditions where noise prevents the reliable determination of film thickness and the loss tangent. On the other hand, we show that there are conditions where it is possible to determine all five parameters. We relate these conditions to the mathematical properties of the model in terms of simple conceptual diagrams that can help users understand the model’s behavior. Finally, we present new open source software for QCMD data analysis written in Python, PyQTM.
You may read the full paper here.
Effect of Noise on Determining Ultrathin-Film Parameters from QCM-D Data with the Viscoelastic Model
Nanoporous Metal–Organic Framework Thin Films Prepared Directly from Gaseous Precursors by Atomic and Molecular Layer Deposition: Implications for Microelectronics
Authors: Jenna Multia, Dmitry E. Kravchenko, Víctor Rubio-Giménez, Anish Philip, Rob Ameloot, and Maarit Karppinen
Journal: ACS Appl. Nano Mater. (2023)
Abstract
Atomic/molecular layer deposition (ALD/MLD) allows for the direct gas-phase synthesis of crystalline metal–organic framework (MOF) thin films. Here, we show for the first time using krypton and methanol physisorption measurements that ALD/MLD-fabricated copper 1,4-benzenedicarboxylate (Cu-BDC) ultrathin films possess accessible porosity matching that of the corresponding bulk MOF.
You may read the full paper here.
Nanoporous Metal–Organic Framework Thin Films Prepared Directly from Gaseous Precursors by Atomic and Molecular Layer Deposition: Implications for Microelectronics
