scholarly journals Mechanisms for destabilisation of RNA viruses at air-water and liquid-liquid interfaces

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
C. A. Brackley ◽  
A. Lips ◽  
A. Morozov ◽  
W. C. K. Poon ◽  
D. Marenduzzo
Keyword(s):  
Rna Viruses ◽  
Rna Virus ◽  
Detailed Balance ◽  
Water Interface ◽  
Liquid Interfaces ◽  
Surface Disinfection ◽  
Effective Strategies ◽  
Air Water Interface ◽  
Electrostatic Free Energy ◽  
Cleaning And Disinfection

AbstractUnderstanding the interactions between viruses and surfaces or interfaces is important, as they provide the principles underpinning the cleaning and disinfection of contaminated surfaces. Yet, the physics of such interactions is currently poorly understood. For instance, there are longstanding experimental observations suggesting that the presence of air-water interfaces can generically inactivate and kill viruses, yet the mechanism underlying this phenomenon remains unknown. Here we use theory and simulations to show that electrostatics may provide one such mechanism, and that this is very general. Thus, we predict that the electrostatic free energy of an RNA virus should increase by several thousands of kBT as the virion breaches an air-water interface. We also show that the fate of a virus approaching a generic liquid-liquid interface depends strongly on the detailed balance between interfacial and electrostatic forces, which can be tuned, for instance, by choosing different media to contact a virus-laden respiratory droplet. Tunability arises because both the electrostatic and interfacial forces scale similarly with viral size. We propose that these results can be used to design effective strategies for surface disinfection.

In situ structure and force characterization of 2D nano-colloids at the air/water interface

Soft Matter ◽  
2019 ◽  
Vol 15 (42) ◽  
pp. 8475-8482
Author(s):  
Giovanni Li-Destri ◽  
Roberta Ruffino ◽  
Nunzio Tuccitto ◽  
Giovanni Marletta
Keyword(s):  
Quantitative Determination ◽  
Experimental Method ◽  
Water Interface ◽  
Liquid Interfaces ◽  
Interaction Forces ◽  
Air Water Interface

We have developed a novel experimental method, which enables quantitative determination of interaction forces between interfacial nanoparticles as a function of the inter-particle distance at liquid interfaces.

scholarly journals Spontaneous oscillations due to solutal Marangoni instability: air/water interface

2012 ◽  
Vol 10 (5) ◽  
pp. 1423-1441 ◽  
Author(s):  
Nina Kovalchuk
Keyword(s):  
Surface Tension ◽  
Dissipative Structures ◽  
Water Interface ◽  
Liquid Interfaces ◽  
Marangoni Instability ◽  
Air Water Interface ◽  
Surfactant Transfer ◽  
Far From Equilibrium ◽  
Spontaneous Oscillations ◽  
Steady Convection

AbstractSystems far from equilibrium are able to self-organize and often demonstrate the formation of a large variety of dissipative structures. In systems with free liquid interfaces, self-organization is frequently associated with Marangoni instability. The development of solutal Marangoni instability can have specific features depending on the properties of adsorbed surfactant monolayer. Here we discuss a general approach to describe solutal Marangoni instability and review in details the recent experimental and theoretical results for a system where the specific properties of adsorbed layers are crucial for the observed dynamic regimes. In this system, Marangoni instability is a result of surfactant transfer from a small droplet located in the bulk of water to air/water interface. Various dynamic regimes, such as quasi-steady convection with a monotonous decrease of surface tension, spontaneous oscillations of surface tension, or their combination, are predicted by numerical simulations and observed experimentally. The particular dynamic regime and oscillation characteristics depend on the surfactant properties and the system aspect ratio.

scholarly journals Soft electrostatic repulsion in particle monolayers at liquid interfaces: surface pressure and effect of aggregation

2016 ◽  
Vol 374 (2072) ◽  
pp. 20150130 ◽  
Author(s):  
Peter A. Kralchevsky ◽  
Krassimir D. Danov ◽  
Plamen V. Petkov
Keyword(s):  
Theoretical Model ◽  
Surface Pressure ◽  
Charged Particles ◽  
Interparticle Distance ◽  
Electrostatic Repulsion ◽  
Water Interface ◽  
Liquid Interfaces ◽  
Polar Fluid ◽  
Air Water Interface ◽  
Oil Water

Non-densely packed interfacial monolayers from charged micrometre-sized colloid particles find applications for producing micropatterned surfaces. The soft electrostatic repulsion between the particles in a monolayer on an air/water (or oil/water) interface is mediated by the non-polar fluid, where Debye screening is absent and the distances between the particles are considerably greater than their diameters. Surface pressure versus area isotherms were measured at the air/water interface. The experiments show that asymptotically the surface pressure is inversely proportional to the third power of the interparticle distance. A theoretical model is developed that predicts not only the aforementioned asymptotic law but also the whole surface pressure versus area dependence. An increase in the surface pressure upon aggregation of charged particles in the interfacial monolayers is experimentally established. This effect is explained by the developed theoretical model, which predicts that the surface pressure should linearly increase with the square root of the particle mean aggregation number. The effect of added electrolyte on the aggregation is also investigated. The data lead to the conclusion that ‘limited aggregation’ exists in the monolayers of charged particles. In brief, the stronger electrostatic repulsion between the bigger aggregates leads to a higher barrier to their coalescence that, in turn, prevents any further aggregation, i.e. negative feedback is present. This article is part of the themed issue ‘Soft interfacial materials: from fundamentals to formulation’.

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

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