Diffuse-Double Layer at a Membrane-Aqueous Interface Measured with X-Ray Standing Waves

Bedzyk, M. J.; Bommarito, G. M.; Caffrey, Martin; Penner, TL

doi:10.1126/science.2321026

Cited by 195 publications

(137 citation statements)

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“…Important areas of combined SR and multilayer applications are projection and contact x-ray microscopy in the \water window" range ( ¶ = 2.35 { 4.5 nm) [1], X-ray spectroscopy and microscopy using BraggFresnel elements [2,3]. Best quality multilayer mirrors have been used as generators of X-ray standing waves for investigation of structural properties of Blodgett-Langmuir lms [4][5][6]. Extreme ultraviolet (EUV) projection lithography in the 13 nm spectral region using both pulse plasma and SR sources seems to be potentially the largest application eld for multilayer developments [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Multilayer optics for XUV spectral region: technology fabrication and applications

et al. 2003

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We present research investigations in the eld of multilayer optics in X-ray and extreme ultra-violet ranges (XUV), aimed at the development of optical elements for applications in experiments in physics and in scienti c instrumentation. We discuss normal incidence multilayer optics in the spectral region of \water window", multilayer optics for collimation and focusing of hard X-rays, multilayer dispersing elements for X-ray spectroscopy of high-temperature plasma, multilayer dispersing elements for analysis of low Z-elements. Our research pays special attention to optimization of multilayer optics for projection EUV-lithography ( ¶ = 13nm) and short period multilayer optics.

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Section: Introductionmentioning

confidence: 99%

Multilayer optics for XUV spectral region: technology fabrication and applications

et al. 2003

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“…This principle has been exploited for the study of interfacial phenomena involving solid, liquid, and gas phases (8)(9)(10)(11)(12)(13)(14)(15)(16). High resolution perpendicular to the interface is implied by SWXF experiments in Bragg reflection configuration, in which case planar, nanometric multilayers are used to create strongly modulated standing waves above the terminal surface close to the Bragg condition (9,10). However, such high-resolution studies have thus far dealt only with the fluorescence of comparatively heavy elements.…”

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confidence: 99%

Atom-scale depth localization of biologically important chemical elements in molecular layers

Schneck

Scoppola

Drnec

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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In nature, biomolecules are often organized as functional thin layers in interfacial architectures, the most prominent examples being biological membranes. Biomolecular layers play also important roles in context with biotechnological surfaces, for instance, when they are the result of adsorption processes. For the understanding of many biological or biotechnologically relevant phenomena, detailed structural insight into the involved biomolecular layers is required. Here, we use standing-wave X-ray fluorescence (SWXF) to localize chemical elements in solid-supported lipid and protein layers with near-Ångstrom precision. The technique complements traditional specular reflectometry experiments that merely yield the layers' global density profiles. While earlier work mostly focused on relatively heavy elements, typically metal ions, we show that it is also possible to determine the position of the comparatively light elements S and P, which are found in the most abundant classes of biomolecules and are therefore particularly important. With that, we overcome the need of artificial heavy atom labels, the main obstacle to a broader application of high-resolution SWXF in the fields of biology and soft matter. This work may thus constitute the basis for the label-free, element-specific structural investigation of complex biomolecular layers and biological surfaces.surfaces | interfaces | lipid membranes | protein adsorption | X-ray scattering N anometric biomolecular layers in interfacial geometries are key components of biological matter. Biological membranes, for example, are 2D molecular structures composed mainly of lipids and proteins in an aqueous environment (1, 2). Interfacial biomolecular layers are also important from a biotechnological perspective, where surfaces are often designed to selectively promote or prevent the adsorption of bio(macro)molecules from solution (3). To investigate the diverse behavior of biomolecules at interfaces, well-defined planar model systems of biological and biotechnologically relevant interfaces have been established (4, 5). Processes involving biomolecules at interfaces are typically accompanied by a spatial reorganization of molecules, changes in molecular conformations, or the adsorption of molecules in a chemically heterogeneous environment (6). Structural insight on the nanometer scale is therefore of paramount importance.X-ray and neutron scattering are uniquely suited for the structural investigation of biomolecular systems. Specular reflectometry reveals matter density profiles perpendicular to a planar interface. However, it is generally difficult to elucidate molecular conformations and elemental distributions from such "global" density profiles. In contrast, standing-wave X-ray fluorescence (SWXF) allows determining element-specific density profiles across an interface. The SWXF technique is based on the elementcharacteristic fluorescence induced by a standing X-ray wave. The latter is formed by interference of the incident and reflected waves and its shape depends o...

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“…For a layer of fluorescing atoms at a fixed position z, the fluorescent intensity is proportional to the standing wave intensity at the atom layer position (26). For a diffuse or continuous metal distribution, which we assume for our experiments, the net fluorescence yield, Y( ), is given by (24,27,28) Y͑ ͒ ϰ ͵ N͑z͒ I͑z, ͒dz,…”

mentioning

confidence: 99%

“…Previous studies have shown the utility of the long-period XSW technique for determining the spatial distribution of heavy metal ions within a variety of organic thin films and model membranes formed on mirror surfaces (23)(24)(25). Long-period XSWs are generated from the interference between an incident and reflected x-ray beam at incident angles below the critical angle for total external reflection of the substrate (Ϸ160 mdeg and 180 mdeg for ␣-Al 2 O 3 and ␣-Fe 2 O 3 , at 14 keV) (Fig.…”

mentioning

confidence: 99%

Pb(II) distributions at biofilm–metal oxide interfaces

Templeton

Trainor

Traina

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

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The distribution of aqueous Pb(II) sorbed at the interface between Burkholderia cepacia biofilms and hematite (␣-Fe 2O3) or corundum (␣-Al 2O3) surfaces has been probed by using an application of the long-period x-ray standing wave technique. Attached bacteria and adsorbed organic matter may interfere with sorption processes on metal oxide surfaces by changing the characteristics of the electrical double layer at the solid-solution interface, blocking surface sites, or providing a variety of new sites for metal binding. In this work, Pb L ␣ fluorescence yield profiles for samples equilibrated with 10 ؊7 to 10 ؊3.8 M Pb(II) were measured and modeled to determine quantitatively the partitioning of Pb(II) at the biofilmmetal oxide interface. Our data show that the reactive sites on the metal oxide surfaces were not passivated by the formation of a monolayer biofilm. Instead, high-energy surface sites on the metal oxides form the dominant sink for Pb(II) at submicromolar concentrations, following the trend ␣-Fe2O3 (0001) > ␣-Al2O3 (11 02) > ␣-Al2O3 (0001), despite the greater site density within the overlying biofilms. At [Pb] > 10 ؊6 M, significant Pb uptake by the biofilms was observed.

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Diffuse-Double Layer at a Membrane-Aqueous Interface Measured with X-Ray Standing Waves

Cited by 195 publications

References 13 publications

Multilayer optics for XUV spectral region: technology fabrication and applications

Multilayer optics for XUV spectral region: technology fabrication and applications

Atom-scale depth localization of biologically important chemical elements in molecular layers

Pb(II) distributions at biofilm–metal oxide interfaces

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