scholarly journals Fluorinated Surfactant Adsorption on Mineral Surfaces: Implications for PFAS Fate and Transport in the Environment

Surfaces ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 516-566 ◽  
Author(s):  
Anthony V. Alves ◽  
Marina Tsianou ◽  
Paschalis Alexandridis
Keyword(s):  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Mineral Surfaces ◽  
Product Packaging ◽  
Fluorinated Surfactants ◽  
Fluorinated Surfactant ◽  
Kinetics Of Adsorption ◽  
Head Groups ◽  
Underlying Mechanisms ◽  
Kinetics Of

Fluorinated surfactants, which fall under the class of per- and polyfluoroalkyl substances (PFAS), are amphiphilic molecules that comprise hydrophobic fluorocarbon chains and hydrophilic head-groups. Fluorinated surfactants have been utilized in many applications, e.g., fire-fighting foams, paints, household/kitchenware items, product packaging, and fabrics. These compounds then made their way into the environment, and have been detected in soil, fresh water, and seawater. From there, they can enter human bodies. Fluorinated surfactants are persistent in water and soil environments, and their adsorption onto mineral surfaces contributes to this persistence. This review examines how fluorinated surfactants adsorb onto mineral surfaces, by analyzing the thermodynamics and kinetics of adsorption, and the underlying mechanisms. Adsorption of fluorinated surfactants onto mineral surfaces can be explained by electrostatic interactions, hydrophobic interactions, hydrogen bonding, and ligand and ion exchange. The aqueous pH, varying salt or humic acid concentrations, and the surfactant chemistry can influence the adsorption of fluorinated surfactants onto mineral surfaces. Further research is needed on fluorinated surfactant adsorbent materials to treat drinking water, and on strategies that can modulate the fate of these compounds in specific environmental locations.

scholarly journals Exploring the kinetic selectivity of drugs targeting the β1-adrenoceptor

2021 ◽  
Author(s):  
David A. Sykes ◽  
Mireia Jiménez-Rosés ◽  
John Reilly ◽  
Robin A. Fairhurst ◽  
Steven J. Charlton ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Binding Pocket ◽  
Log P ◽  
Association Rate ◽  
Immobilized Artificial Membrane ◽  
Kinetics Of ◽  
Positively Charged ◽  
Charged Ligands

AbstractIn this study, we report the β1-adrenoceptor binding kinetics of several clinically relevant β1/2-adrenoceptor (β1/2AR) agonists and antagonists. We demonstrate that the physicochemical properties of a molecule directly affect its kinetic association rate (kon) and affinity for the target. In contrast to our findings at the β2-adrenoceptor, a drug’s immobilized artificial membrane partition coefficient (KIAM), reflecting both hydrophobic and electrostatic interactions of the drug with the charged surface of biological membranes, was no better predictor than simple hydrophobicity measurements such as log P or logD7.4, characterized by a distribution between water and a non-aqueous organic phase (e.g. n-octanol) at predicting association rate. Overall, this suggests that hydrophobic interactions rather than a combination of polar and hydrophobic interactions play a more prominent role in dictating the binding of these ligands to the β1-adrenoceptor.Using a combination of kinetic data, detailed structural and physicochemical information we rationalize the above findings and speculate that the association of positively charged ligands at the β1AR is curtailed somewhat by its predominantly neutral/positive charged extracellular surface. Consequently, hydrophobic interactions in the ligand binding pocket dominate the kinetics of ligand binding. In comparison at the β2AR, a combination of hydrophobicity and negative charge attracts basic, positively charged ligands to the receptor’s surface promoting the kinetics of ligand binding. Additionally, we reveal the potential role kinetics plays in the on-target and off-target pharmacology of clinically used β-blockers.

Influence of Brain Gangliosides on the Formation and Properties of Supported Lipid Bilayers for Binding Kinetics Studies

2018 ◽  
Author(s):  
Luke Jordan ◽  
Nathan Wittenberg
Keyword(s):  
Lipid Bilayers ◽  
Binding Kinetics ◽  
Supported Lipid Bilayers ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Supported Lipid Bilayer ◽  
Head Groups ◽  
Lipid Diffusion ◽  
Kinetics Of ◽  
Brain Gangliosides

This is a comprehensive study of the effects of the four major brain gangliosides (GM1, GD1b, GD1a, and GT1b) on the adsorption and rupture of phospholipid vesicles on SiO2 surfaces for the formation of supported lipid bilayer (SLB) membranes. Using quartz crystal microbalance with dissipation monitoring (QCM-D) we show that gangliosides GD1a and GT1b significantly slow the SLB formation process, whereas GM1 and GD1b have smaller effects. This is likely due to the net ganglioside charge as well as the positions of acidic sugar groups on ganglioside glycan head groups. Data is included that shows calcium can accelerate the formation of ganglioside-rich SLBs. Using fluorescence recovery after photobleaching (FRAP) we also show that the presence of gangliosides significantly reduces lipid diffusion coefficients in SLBs in a concentration-dependent manner. Finally, using QCM-D and GD1a-rich SLB membranes we measure the binding kinetics of an anti-GD1a antibody that has similarities to a monoclonal antibody that is a hallmark of a variant of Guillain-Barre syndrome.

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

scholarly journals Addressing a lattice of rotatable molecular dipoles with the electric field of an STM tip

2021 ◽  
Vol 23 (8) ◽  
pp. 4874-4881
Author(s):  
Timo Frauhammer ◽  
Lukas Gerhard ◽  
Kevin Edelmann ◽  
Marcin Lindner ◽  
Michal Valášek ◽  
...  
Keyword(s):  
Electric Field ◽  
Electrostatic Interactions ◽  
Head Groups

Electrostatic interactions within a lattice of freestanding rotatable head groups mounted on tripodal molecular platforms.

scholarly journals Fibronectin–collagen binding and requirement during cellular adhesion

1980 ◽  
Vol 186 (2) ◽  
pp. 551-559 ◽  
Author(s):  
Leslie I. Gold ◽  
Edward Pearlstein
Keyword(s):  
Chick Embryo ◽  
Human Plasma ◽  
Hydrophobic Interactions ◽  
Human Fibroblasts ◽  
Sodium Dodecyl ◽  
Cellular Adhesion ◽  
Adhesion Assay ◽  
Human Umbilical Cord ◽  
Ionic Detergents ◽  
Kinetics Of

Fibronectin isolated from human plasma and from the extracellular matrices of cell monolayers mediates the attachment in vitro and spreading of trypsin-treated cells on a collagen substratum. Fibronectin-dependent kinetics of cellular attachment to collagen were studied for several adherent cell types. It was shown that trypsin-treated human umbilical-cord cells, mouse sarcoma CMT81 cells, endothelial cells, and human fibroblasts from a patient with Glanzmann's disease were completely dependent on fibronectin for their attachment to collagen, whereas guinea-pig and monkey smooth-muscle cells and chick-embryo secondary fibroblasts displayed varying degrees of dependence on fibronectin for their attachment. Radiolabelled human plasma fibronectin possessed similar affinity for collagen types I, II and III from a variety of sources. The fibronectin bound equally well to the collagens with or without prior urea treatment. However, in the fibronectin-mediated adhesion assay using PyBHK fibroblasts, a greater number of cells adhered and more spreading was observed on urea-treated collagen. Fibronectin extracted from the extracellular matrix of chick-embryo fibroblasts and that purified from human plasma demonstrated very similar kinetics of complexing to collagencoated tissue-culture dishes. Fibronectin from both sources bound to collagen in the presence of 0.05–4.0m-NaCl and over the pH range 2.6–10.6. The binding was inhibited when fibronectin was incubated with 40–80% ethylene glycol, the ionic detergents sodium dodecyl sulphate and deoxycholate, and the non-ionic detergents Nonidet P-40, Tween 80 and Triton X-100, all at a concentration of 0.1%. From these results we proposed that fibronectin–collagen complexing is mainly attributable to hydrophobic interactions.

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