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1.
J Colloid Interface Sci ; 661: 588-597, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38308897

RESUMEN

Interactions between nanoparticles and the mucus layer are crucial to understand the behaviours in biological environments and design drug delivery systems. In this study, we developed a kinetic deposition model for the dynamic mucin-nanoparticle interactions using quartz crystal microbalance with dissipation (QCM-D). We investigated the effects of the physiochemical properties of several nanoparticles (including size, charge, and shape) and the physiological conditions on the mucin-nanoparticle interaction. Interestingly, layered double hydroxide (LDH) nanoparticles showed stronger interactions with the mucus layer compared to other types of nanoparticles due to their unique plate-like morphology. In specific for sheet-like LDH nanoparticles, our model found that their equilibrium adsorption capacity (Qe) followed the Langmuir adsorption isotherm, and the adsorption rate (k1) increased proportionally with the nanoparticle concentration. In addition, the particle size and thickness affected Qe and the surface coverage. Furthermore, bovine serum albumin (BSA) coating dramatically increased k1 of LDH nanoparticles. We proposed a novel mechanism to elucidate mucin-nanoparticle interactions, shedding light on the synergistic roles of drag force (Fd), repulsive force (Fr), and adsorptive force (Fa). These findings offer valuable insights into the complex mucin-nanoparticle interactions and provide guidance for the design of drug delivery systems.


Asunto(s)
Mucinas , Nanopartículas , Adsorción , Tamaño de la Partícula , Tecnicas de Microbalanza del Cristal de Cuarzo , Propiedades de Superficie , Albúmina Sérica Bovina/química
2.
Gels ; 9(12)2023 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-38131914

RESUMEN

α-Form hydrated crystals form a lamellar gel in which the alkyl chains of the amphiphilic molecules are hexagonally arranged within bilayers below the gel-liquid crystal phase transition temperature. In practice, the lamellar gel network with excess water is called an "α-gel", particularly in the cosmetics industry. In this study, the hydration or water sorption of amphiphilic materials in water vapor was assessed using a humidity-controlled quartz crystal microbalance with dissipation monitoring (QCM-D) technique. The amphiphilic materials used in this study were hexadecyl phosphate salts neutralized with L-arginine (C16P-Arg), CsOH (C16P-Cs), KOH (C16P-K), and NaOH (C16P-Na). Small- and wide-angle X-ray scattering measurements revealed that C16P-Arg and C16P-Cs yielded α-form hydrated crystals. Humidity-controlled QCM-D measurements demonstrated that C16P-Arg and C16P-Cs more readily underwent hydration or water sorption than C16P-K and C16P-Na. The key conclusion is that the significant hydration ability of C16P-Arg and C16P-Cs promotes the formation of the corresponding α-form hydrated crystals.

3.
Biosensors (Basel) ; 13(8)2023 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-37622870

RESUMEN

The spike (S) protein and its receptor-binding domain (RBD) of the coronavirus SARS-CoV-2 have been continually evolving, yielding the majority of significant missense mutations and new variants of concern. In this study, we examined how monoclonal antibodies against RBD (mAbs-SCoV2-RBD) and polyclonal antibodies present in convalescent human serum specifically interact with the S protein of wild-type and SARS-CoV-2 variants of concern (VOCs) in real time and how this can be reflected through surface mass density. Moreover, we combined two distinct, label-free measurement techniques: one based on changes in surface electromagnetic waves after reflection from the surface, and the other on changes in acoustic waves. The results demonstrated that dry surface mass density (ΓSE) of mAbs-SCoV2-RBD attached to the RBD of the S protein decreases three-fold, from 148 ng/cm2 to 46 ng/cm2, due to the B.1.351 or so-called beta mutation of coronavirus and its S protein (SCoV2-ß). Consequently, the obtained wet mass ΓQCM-D resulted in values two times lower, from 319 ng/cm2 to 158 ng/cm2, and the hydration of mAbs-SCoV2-RBD/SCoV2-ß immune complex was 70.88%. Conversely, when polyclonal antibodies present in convalescent human serum form immune complexes with the S protein of SARS-CoV-2 variants of concern, the ΓSE decreased from 279 ng/cm2 to 249 ng/cm2, and ΓQCM-D from 1545 ng/cm2 to 1366 ng/cm2. These results can give insights into the differences between the interaction of monoclonal and polyclonal antibodies with SARS-CoV-2 VOCs.


Asunto(s)
Anticuerpos Monoclonales , COVID-19 , Humanos , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus
4.
Heliyon ; 9(6): e17163, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37484311

RESUMEN

To decrease the negative impact of surfactants, the idea of using purified water in washing has been proposed. Previous studies showed that purified water facilitates the roll-up mechanism by promoting electrostatic interactions between the surface and the soil. However, washing mechanisms can be dependent on the amount of remaining soil. In this work we studied the removal of thin Vaseline films and thicker oil films from hydrophilic surfaces using multiple washing cycles at different temperatures. The Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and gravimetric analysis were used for thin and thick films respectively. In QCM-D experiments most of the thin film was removed during the first two cycles, while following cycles did not substantially affect washing efficiency; increased temperature facilitated the washing process. Gravimetric analysis showed that the washing of thicker films can be divided into two regimes. During the first, exponential, regime the amount of oil on the surface is high and surface mechanisms, such as roll-up, dominate. Oil droplets are kinetically stabilized in purified water by electrostatic interactions. As the amount of oil on the surface decreases, the second, linear, regime is introduced. The removal of oil occurs by equilibrium bulk mechanisms, where electrostatic interactions are less important.

5.
J Oleo Sci ; 72(7): 709-714, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37380486

RESUMEN

The adsorption and lubrication of an amino acid-based surfactant at the solid/liquid interface were studied in the presence of calcium ions. The surfactant used here was disodium N-dodecanoylglutamate (C12Glu-2Na). The solid surface used in this study was hydrophobically modified to mimic the hydrophobicity of the skin surface. Quartz crystal microbalance with dissipation monitoring (QCM-D) measurements revealed that the anionic surfactant was adsorbed on the hydrophobically modified solid surface. The replacement of the surfactant solution with CaCl2 aqueous solution resulted in the desorption of the surfactant to some extent; however, a rigid and elastic adsorption film interacting with calcium ions remained on the solid surface. The adsorption film containing calcium ions lowered the kinetic friction coefficient in aqueous media. The insoluble calcium salt of the surfactant, dispersed in the solution phase, also contributed to lubrication. We expect that the usability of personal care products formulated using amino acid-based surfactants is relevant to such adsorption and lubrication properties.


Asunto(s)
Surfactantes Pulmonares , Tensoactivos , Ácido Glutámico , Calcio , Adsorción , Lubrificación , Lipoproteínas , Aminoácidos , Iones
6.
Biotechnol Bioeng ; 120(8): 2253-2268, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37386894

RESUMEN

Carbohydrate binding modules (CBMs) are noncatalytic domains that assist tethered catalytic domains in substrate targeting. CBMs have therefore been used to visualize distinct polysaccharides present in the cell wall of plant cells and tissues. However, most previous studies provide a qualitative analysis of CBM-polysaccharide interactions, with limited characterization of engineered tandem CBM designs for recognizing polysaccharides like cellulose and limited application of CBM-based probes to visualize cellulose fibrils synthesis in model plant protoplasts with regenerating cell walls. Here, we examine the dynamic interactions of engineered type-A CBMs from families 3a and 64 with crystalline cellulose-I and phosphoric acid swollen cellulose. We generated tandem CBM designs to determine various characteristic properties including binding reversibility toward cellulose-I using equilibrium binding assays. To compute the adsorption (nkon ) and desorption (koff ) rate constants of single versus tandem CBM designs toward nanocrystalline cellulose, we employed dynamic kinetic binding assays using quartz crystal microbalance with dissipation. Our results indicate that tandem CBM3a exhibited the highest adsorption rate to cellulose and displayed reversible binding to both crystalline/amorphous cellulose, unlike other CBM designs, making tandem CBM3a better suited for live plant cell wall biosynthesis imaging applications. We used several engineered CBMs to visualize Arabidopsis thaliana protoplasts with regenerated cell walls using confocal laser scanning microscopy and wide-field fluorescence microscopy. Lastly, we also demonstrated how CBMs as probe reagents can enable in situ visualization of cellulose fibrils during cell wall regeneration in Arabidopsis protoplasts.


Asunto(s)
Celulosa , Protoplastos , Humanos , Protoplastos/metabolismo , Celulosa/metabolismo , Polisacáridos/metabolismo , Plantas/química , Metabolismo de los Hidratos de Carbono
7.
Nano Lett ; 23(14): 6760-6767, 2023 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-37279451

RESUMEN

Easily deploying new vaccines globally to combat disease outbreaks has been highlighted as a major necessity by the World Health Organization. RNA-based vaccines using lipid nanoparticles (LNPs) as a drug delivery system were employed to great effect during the recent COVID-19 pandemic. However, LNPs are still unstable at room temperature and agglomerate over time during storage, rendering them ineffective for intracellular delivery. We demonstrate the suitability of nanohole arrays (nanopackaging) as patterned surfaces to separate and store functionalized LNPs (fLNPs) in individual recesses, which can be expanded to other therapeutics. Encapsulating calcein as a model drug, we show through confocal microscopy the effective loading of fLNPs into our nanopackaging for both wet and dry systems. We prove quantifiably pH-mediated capture and subsequent unloading of over 30% of the fLNPs using QCM-D on alumina surfaces altering the pH from 5.5 to 7, displaying controllable storage at the nanoscale.


Asunto(s)
COVID-19 , Nanopartículas , Humanos , Pandemias , COVID-19/prevención & control , Sistemas de Liberación de Medicamentos
8.
Carbohydr Polym ; 313: 120810, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37182942

RESUMEN

Polysaccharides are excellent network formers and are often processed into films from water solutions. Despite being hydrophilic polysaccharides, the typical xylans liberated from wood are sparsely soluble in water. We have previously suggested that an additional piece to the solubilization puzzle is modification of the xylan backbone via oxidative cleavage of the saccharide ring. Here, we demonstrate the influence of the degree of modification, i.e., degree of oxidation (DO) on xylan solubilization and consequent film formation and stability. Oxidized and reduced wood xylans (i.e., dialcohol xylans) with the highest DO (77 %) within the series exhibited the smallest hydrodynamic diameter (dh) of 60 nm in dimethylsulfoxide (DMSO). We transferred the modified xylans into films credit to their established solubility and then quantified the film water interactions. Dialcohol xylans with intermediate DOs (42 and 63 %) did not form continuous films. The films swelled slightly when subjected to humidity. However, the film with the highest DO demonstrated a significant moisture uptake that depended on the film mass and was not observed with the other modified grades or with unmodified xylan.

9.
Colloids Surf B Biointerfaces ; 227: 113341, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37210796

RESUMEN

The combination of in vitro models of biological membranes based on solid-supported lipid bilayers (SLBs) and of surface sensitive techniques, such as neutron reflectometry (NR), atomic force microscopy (AFM) and quartz crystal microbalance with dissipation monitoring (QCM-D), is well suited to provide quantitative information about molecular level interactions and lipid spatial distributions. In this work, cellular plasma membranes have been mimicked by designing complex SLB, containing phosphatidylinositol 4,5-bisphosphate (PtdIns4,5P2) lipids as well as incorporating synthetic lipo-peptides that simulate the cytoplasmic tails of transmembrane proteins. The QCM-D results revealed that the adsorption and fusion kinetics of PtdIns4,5P2 are highly dependent of Mg2+. Additionally, it was shown that increasing concentrations of PtdIns4,5P2 leads to the formation of SLBs with higher homogeneity. The presence of PtdIns4,5P2 clusters was visualized by AFM. NR provided important insights about the structural organization of the various components within the SLB, highlighting that the leaflet symmetry of these SLBs is broken by the presence of CD4-derived cargo peptides. Finally, we foresee our study to be a starting point for more sophisticated in vitro models of biological membranes with the incorporation of inositol phospholipids and synthetic endocytic motifs.


Asunto(s)
Fosfatidilinositoles , Tecnicas de Microbalanza del Cristal de Cuarzo , Fosfatidilinositoles/química , Tecnicas de Microbalanza del Cristal de Cuarzo/métodos , Microscopía de Fuerza Atómica , Membrana Dobles de Lípidos/química , Péptidos/química , Neutrones
10.
Int J Biol Macromol ; 242(Pt 3): 125013, 2023 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-37224910

RESUMEN

Cationic starch is the most widely used paper strength additive for papermaking wet end applications. However, it remains unclear how differently quaternized amylose (QAM) and amylopectin (QAP) are adsorbed on the fiber surface and their relative contribution to the inter-fiber bonding of papers. Herein, separated amylose and amylopectin were quaternized with different degrees of substitution (DS). After that, the adsorption behaviors of QAM and QAP on the fiber surface, the viscoelastic properties of the adlayers and their strength enhancement to fiber networks were comparatively characterized. Based on the results, the morphology visualizations of the starch structure displayed a strong impact on the adsorbed structural distributions of QAM and QAP. QAM adlayer with a helical linear or slightly branched structure was thin and rigid, while the QAP adlayer with a highly branched structure was thick and soft. In addition, the DS, pH and ionic strength had some impacts on the adsorption layer as well. Regarding the paper strength enhancement, the DS of QAM correlated positively to the paper strength, whereas the DS of QAP correlated inversely. The results provide a deep understanding of the impacts of starch morphology on performance and offer us some practical guidelines in starch selection.


Asunto(s)
Amilopectina , Amilosa , Amilopectina/química , Amilosa/química , Adsorción , Almidón/química , Carbohidratos
11.
Int J Biol Macromol ; 239: 124286, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37011749

RESUMEN

Cationic polyelectrolytes (PEs) are commonly used additives in manufacturing of cellulose based products such as regenerated fibers and paper to tailor their product properties. Here we are studying the adsorption of poly(diallyldimethylammonium chloride), PD, on cellulose, using in situ surface plasmon resonance spectroscopy (SPR) measurements. We employ model surfaces from regenerated cellulose xanthate (CX) and trimethylsilyl cellulose (TMSC), mimicking industrially relevant regenerated cellulose substrates. The effects of the PDs molecular weight were strongly depending on the ionic strength and type of electrolyte (NaCl vs CaCl2). Without electrolytes, the adsorption was monolayer-type, i.e. independent of molecular weight. At moderate ionic strength, adsorption increased due to more pronounced PE coiling, while at high ionic strength electrostatic shielding strongly reduced adsorption of PDs. Results exhibited pronounced differences for the chosen substrates (cellulose regenerated from xanthate (CXreg) vs. regenerated from trimethylsilyl cellulose, TMSCreg). Consistently higher adsorbed amounts of the PD were determined on CXreg surfaces compared TMSC. This can be attributed to a more negative zeta potential, a higher AFM roughness and a higher degree of swelling (investigated by QCM-D) of the CXreg substrates.


Asunto(s)
Celulosa , Electrólitos , Adsorción , Peso Molecular , Propiedades de Superficie , Celulosa/química , Electrólitos/química
12.
ACS Appl Mater Interfaces ; 15(15): 19582-19592, 2023 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-37022755

RESUMEN

Inspired by mussel proteins that enable surface binding in harsh marine environments, we envisioned a platform of protein-repellent macromolecules based on poly(2-ethyl-2-oxazoline) carrying catechol and cationic functional groups. To facilitate surface attachment, catechol units were installed by copolymerizing a functional comonomer, i.e., 2-(3,4-dimethoxyphenyl)-2-oxazoline, in a gradient fashion. Cationic units were introduced by partial acidic hydrolysis. The surface affinity of these polymers was probed using a quartz crystal microbalance with dissipation monitoring (QCM-D), and it was found that polymers with catechol units had a strong tendency to form surface-bound layers on different substrates, i.e., gold, iron, borosilicate, and polystyrene. While the neutral catechol-containing polymers showed strong, but uncontrolled binding, the ones with additional cationic units were able to form defined and durable polymer films. These coatings were able to prevent the attachment of different model proteins, i.e., bovine serum albumin (BSA), fibrinogen (FI), or lysozyme (LYZ). The herein-introduced platform offers straightforward access to nonfouling surface coatings using a biomimetic approach.


Asunto(s)
Poliaminas , Polímeros , Polímeros/química , Albúmina Sérica Bovina/química , Tecnicas de Microbalanza del Cristal de Cuarzo , Proteínas de la Membrana , Catecoles , Propiedades de Superficie , Adsorción
13.
Small ; 19(23): e2207125, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36899445

RESUMEN

Membrane fusion is essential for the basal functionality of eukaryotic cells. In physiological conditions, fusion events are regulated by a wide range of specialized proteins, operating with finely tuned local lipid composition and ionic environment. Fusogenic proteins, assisted by membrane cholesterol and calcium ions, provide the mechanical energy necessary to achieve vesicle fusion in neuromediator release. Similar cooperative effects must be explored when considering synthetic approaches for controlled membrane fusion. We show that liposomes decorated with amphiphilic Au nanoparticles (AuLips) can act as minimal tunable fusion machinery. AuLips fusion is triggered by divalent ions, while the number of fusion events dramatically changes with, and can be finely tuned by, the liposome cholesterol content. We combine quartz-crystal-microbalance with dissipation monitoring (QCM-D), fluorescence assays, and small-angle X-ray scattering (SAXS) with molecular dynamics (MD) at coarse-grained (CG) resolution, revealing new mechanistic details on the fusogenic activity of amphiphilic Au nanoparticles (AuNPs) and demonstrating the ability of these synthetic nanomaterials to induce fusion regardless of the divalent ion used (Ca2+ or Mg2+ ). The results provide a novel contribution to developing new artificial fusogenic agents for next-generation biomedical applications that require tight control of the rate of fusion events (e.g., targeted drug delivery).


Asunto(s)
Liposomas , Nanopartículas del Metal , Oro , Dispersión del Ángulo Pequeño , Difracción de Rayos X , Proteínas , Colesterol , Iones
14.
Sensors (Basel) ; 23(3)2023 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-36772387

RESUMEN

Quartz crystal microbalance with dissipation monitoring (QCM-D) 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, ∆f/n, and overtone-normalized shifts in half-bandwidth, ΔΓ/n, provided by QCM-D 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 QCM-D data analysis written in Python, PyQTM.

15.
Phytochemistry ; 209: 113618, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36828099

RESUMEN

The membrane interaction characteristics of five antifungal plant defensin peptides: NaD1, and the related HXP4 and L5, as well as NaD2 and the related ZmD32 were studied. These peptides were chosen to cover a broad range of cationic charges with little structural variations, allowing for assessment of the role of charge in their membrane interactions. Membrane permeabilizing activity against C. albicans was confirmed and quantified for benchmarking purposes. Viscoelastic characteristics of the membrane interactions were studied in typical neutral and charged model membranes using quartz crystal microbalance with dissipation (QCM-D. Frequency-dissipation fingerprinting analysis of the QCM-D results revealed that all of the peptides were able to bind to all studied model membranes albeit with slightly different viscoelastic character for each membrane type. However, characteristic disruption patterns were not observed suggesting that the membrane disrupting activity of these defensins is mostly specific to fungal membranes, and that increasing the peptide charge does not enhance their action. The results also show that the presence of specific sterols has a profound effect on the ability of the peptides to disrupt the membrane.


Asunto(s)
Defensinas , Péptidos , Defensinas/química
16.
Artículo en Inglés | MEDLINE | ID: mdl-35999185

RESUMEN

Research into extracellular vesicles (EVs) has grown significantly over the last few decades with EVs being widely regarded as a source of biomarkers for human health and disease with massive clinical potential. Secreted by every cell type in the body, EVs report on the internal cellular conditions across all tissue types. Their presence in readily accessible biofluids makes the potential of EV biosensing highly attractive as a noninvasive diagnostic platform via liquid biopsies. However, their small size (50-250 nm), inherent heterogeneity, and the complexity of the native biofluids introduce challenges for effective characterization, thus, limiting their clinical utility. This has led to a surge in the development of various novel EV biosensing techniques, with capabilities beyond those of conventional methods that have been directly transferred from cell biology. In this review, key detection principles used for EV biosensing are summarized, with a focus on some of the most recent and fundamental developments in the field over the last 5 years. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > In Vitro Nanoparticle-Based Sensing.


Asunto(s)
Técnicas Biosensibles , Exosomas , Vesículas Extracelulares , Humanos , Exosomas/metabolismo , Vesículas Extracelulares/metabolismo , Biomarcadores
17.
J Agric Food Chem ; 71(1): 700-709, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36534057

RESUMEN

Reducing sodium intake without decreasing saltiness perception remains an important target in the food industry. This study developed an effective protocol for evaluating the saltiness perception enhanced by umami compounds. Two sodium chloride solutions (2.00 and 6.00 g/L) were the preferred concentrations for consumers. Two-alternative forced-choice evaluation results confirmed that at a concentration of 2.00 g/L (sodium concentration), the highest replacement ratios of monosodium glutamate and l-alanine (Ala) were 10 and 20% in sodium chloride solution without saltiness intensity decrease, respectively. The highest replacement ratios of l-glycine (Gly) and Ala were 10 and 20% compared to 6.00 g/L, respectively. Temporal dominance of sensations analysis figured out that gum Arabic (GA) could compensate for the decrease of the retention time and increase the overall saltiness perception in the sodium-reduced sample. Quartz crystal microbalance with dissipation results showed that Ala and Gly could inhibit the binding of Na+ to mucin, thereby increasing the saltiness perception. GA exhibited the best saltiness enhancement effect in sodium-reduced solution by producing the nanoparticles from GA, decreasing the stability of the solution system, enhancing the loading effect of mucin on Na+, and prolonging the saltiness perception.


Asunto(s)
Cloruro de Sodio , Gusto , Cloruro de Sodio/análisis , Glutamato de Sodio , Sodio , Mucinas
18.
J Biomed Mater Res A ; 111(4): 440-450, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36537182

RESUMEN

Polymer-protein hybrids can be deployed to improve protein solubility and stability in denaturing environments. While previous work used robotics and active machine learning to inform new designs, further biophysical information is required to ascertain structure-function behavior. Here, we show the value of tandem small-angle x-ray scattering (SAXS) and quartz crystal microbalance with dissipation (QCMD) experiments to reveal detailed polymer-protein interactions with horseradish peroxidase (HRP) as a test case. Of particular interest was the process of polymer-protein complex formation under thermal stress whereby SAXS monitors formation in solution while QCMD follows these dynamics at an interface. The radius of gyration (Rg ) of the protein as measured by SAXS does not change significantly in the presence of polymer under denaturing conditions, but thickness and dissipation changes were observed in QCMD data. SAXS data with and without thermal stress were utilized to create bead models of the potential complexes and denatured enzyme, and each model fit provided insight into the degree of interactions. Additionally, QCMD data demonstrated that HRP deforms by spreading upon surface adsorption at low concentration as shown by longer adsorption times and smaller frequency shifts. In contrast, thermally stressed and highly inactive HRP had faster adsorption kinetics. The combination of SAXS and QCMD serves as a framework for biophysical characterization of interactions between proteins and polymers which could be useful in designing polymer-protein hybrids.


Asunto(s)
Polímeros , Tecnicas de Microbalanza del Cristal de Cuarzo , Dispersión del Ángulo Pequeño , Rayos X , Difracción de Rayos X , Proteínas/química , Peroxidasa de Rábano Silvestre , Cuarzo/química
19.
ACS Appl Bio Mater ; 5(12): 5877-5886, 2022 12 19.
Artículo en Inglés | MEDLINE | ID: mdl-36417663

RESUMEN

Label-free detection of pathogens is of major concern to the microbiologist community. Most procedures require several steps and amplification techniques. Carbohydrates are well-established receptors for host-pathogen interactions, which can be amplified using glycodendritic architectures on the basis of multivalent binding interactions. Given that uropathogenic Escherichia coli bacterial FimH is based on such mannopyranoside-binding interactions, we demonstrate herein that synthetic monomeric and trimeric thiolated α-d-mannosides can be effectively bound to gold substrate-functionalized self-assembled monolayers (SAMs) preactivated with maleimide functionalities. Mannosides grafted onto SAMs were followed using Quartz Crystal Microbalance with Dissipation (QCM-D). Binding recognition efficiency was first evaluated using the plant lectin from Canavalia ensiformis (ConA) also using QCM-D. We showed a direct correlation between the amount of mannoside bound and the lectin attachment. Even though there was less trimer bound (nM/cm2) to the surface, we observed a 7-fold higher amount of lectin anchoring, thus further demonstrating the value of the multivalent interactions. We next examined the relative fimbriated E. coli selective adhesion/capture to either the monomeric or the trimeric mannoside bound to the surface. Our results established the successful engineering of the surfaces to show E. coli adhesion via specific mannopyranoside binding but unexpectedly, the monomeric derivative was more efficient than the trimeric analog, which could be explained by steric hindrance. This approach strongly suggests that it could be broadly applicable to other Gram-negative bacteria sharing analogous carbohydrate-dependent binding interactions.


Asunto(s)
Escherichia coli Uropatógena , Escherichia coli Uropatógena/metabolismo , Manosa/metabolismo , Manósidos/química , Concanavalina A , Lectinas
20.
ACS Appl Mater Interfaces ; 14(41): 46635-46645, 2022 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-36205546

RESUMEN

Formation and evolution of the microscopic solid electrolyte interphase (SEI) at the Mg electrolyte/electrode interface are less reported and need to be completely understood to overcome the compatibility challenges at the Mg anode-electrolyte. In this paper, SEI evolution at the Mg electrolyte/electrode interface is investigated via an in situ electrochemical quartz crystal microbalance with dissipation mode (EQCM-D), electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectrometry (FTIR). Results reveal remarkably different interfacial evolutions for the two Mg electrolyte systems that are studied, a non-halogen Mg(TFSI)2 electrolyte in THF with DMA as a cosolvent (nhMg-DMA electrolyte) versus a halogen-containing all-phenyl complex (APC) electrolyte. The nhMg-DMA electrolyte reports a minuscule SEI formation along with a significant Coulomb loss at the initial electrochemical cycles owing to an electrolyte reconstruction process. Interestingly, a more complicated SEI growth is observed at the later electrochemical cycles accompanied by an improved reversible Mg deposition attributed to the newly formed coordination environment with Mg2+ and ultimately leads to a more homogeneous morphology for the electrochemically deposited Mg0, which maintains a MgF2-rich interface. In contrast, the APC electrolyte shows an extensive SEI formation at its initial electrochemical cycles, followed by a SEI dissolution process upon electrochemical cycling accompanied by an improved coulombic efficiency with trace water and chloride species removed. Therefore, it leads to SEI stabilization progression upon further electrochemical cycling, resulting in elevated charge transport kinetics and superior purity of the electrochemically deposited Mg0. These outstanding findings augment the understanding of the SEI formation and evolution on the Mg interface and pave a way for a future Mg-ion battery design.

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