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An X-ray reflectivity analysis has shown that the composition of liquid substrates affects the structure of deposited Nafion (Teflon copolymer) films. A model of Nafion monomer, developed based on small-angle X-ray scattering data, is used to interpret the results of X-ray reflectivity analysis.

A theoretical formalism for quantitative description of X-ray diffraction from Langmuir monolayers under conditions of total external reflection has been developed. The proposed approach, based on the distorted-wave approximation, allows to consider physical mechanisms for plotting diffraction curves and maps (in the reciprocal space) for real monolayers and describe self-consistently specific features of Bragg peaks. The resulting algorithm can easily be implemented on a personal computer, which provides the opportunities to carry out numerical simulation of experimental two-dimensional diffraction intensity maps and determine reliably both the mean values of structural parameters of layers and their rms deviations.

The effect of anticancer antibiotic doxorubicin on structural organization of anionic lipid monolayers has been studied. X-ray reflectivity and grazing incidence diffraction techniques were applied to monitor the changes in 2D structure and electron density distribution of Langmuir monolayer composed of negatively charged dipalmitoylphosphatidylglycerol (DPPG) and dioleoylphosphatidylserine (DOPS). For comparison, monolayer of zwitterionic dipalmitoylphosphatidylethanolamine (DPPE) also was investigated. The presented experimental results suggest that doxorubicin interaction with anionic lipid monolayers (DPPG and DOPS) proceeds preferentially via electrostatic attraction—positively charged amino groups of doxorubicin bind to negatively charged head groups of phospholipid molecules. Based on the obtained data, the penetration of doxorubicin into the hydrophobic part of anionic lipid monolayers does not occur. X-ray measurements on DPPE monolayer indicated that doxorubicin did not cause any significant alterations of molecular packing in condensed monolayer of zwitterionic DPPE molecules.

High-resolution X-ray techniques were applied to examine the effects of gold nanoparticles (size5 nm) on natural pulmonary surfactant and pure DPPC monolayers preliminarily formed on water subphase in a Langmuir trough. Hydrophobic and hydrophilic nanoparticles were delivered from nanoaerosol using electrodeposition method. Grazing incidence diffraction, X-ray reflectivity, and X-ray standing wave measurements allow to monitor the changes in molecular organization of lipid monolayer and to locate the position of gold nanoparticles. X-ray experiments were performed over a period of 9-14 h. The obtained results evidenced that, on a long time scale, the deposition of nanoparticles, even at low doses, can induce pronounced alterations in lipid monolayer. The presented data can help to elucidate the mechanism of pulmonary translocation of inhaled nanoparticles that is of special interest for biomedical investigations of potential risk of nanoaerosols for human health.

XANES spectra of protein films (hemoglobin and alkaline phosphatase) formed on the surface of a liquid subphase in a Langmuir trough have been obtained experimentally. The potential of X-ray absorption spectroscopy in the total external reflection geometry is demonstrated by the example of a protein film based on hemoglobin subjected to the action of urea. It is established that the presence of 0.09 M urea solution in the subphase enhances significantly the ability of hemoglobin to bind zinc and iron ions. Information about the local atomic environment of zinc ions bound with a hemoglobin molecule is obtained. It is shown that each zinc ion is coordinated by four ligands, two of which are amino acid residues of cysteine and histidine. The general concepts of the molecular mechanisms of accumulation of metal ions under the action of disturbing factors are formulated.

An X-ray study of the interaction of Langmuir monolayers with nanoparticles under the conditions when nanoparticles arrive at the monolayer from the side of the air medium has been performed for the first time. Measurements by the X-ray standing-wave method and two-dimensional diffraction have made it possible to investigate the transport of nanoaerosol particles through a lipid monolayer and observe the structural changes occurring in it. Nanoaerosol particles were formed by electrohydrodynamic sputtering of desalted solutions of ferritin. It was shown that nanoaerosol particles pass through the monolayer without disrupting the two-dimensional packing of lipid molecules. The ferritin molecules penetrating the aqueous subphase after sputtering are found to be adsorbed under the monolayer.

X-ray studies of dipalmitoylphosphatidylcholine (DPPC) single layers on the surface of a liquid provide detailed information on the interaction of metal particles with a single layer upon an increase in the surface pressure up to the collapse. Two complementary X-ray methods are used: grazing incidence diffraction and the X-ray standing waves method. The experimental results obtained for a single layer formed on a colloidal solution of magnetite nanoparticles reveal that the increase in the surface pressure is accompanied by an increase in the concentration of nanoparticles near the surface. In a series of experiments where metal particles of submicron size are sputtered onto a DPPC single layer, a sharp decrease in the intensity of the fluorescence yield from metal atoms is observed while the single layer is compressed. These data suggest that metal particles deposited onto the surface of a single layer were extruded into the aqueous subphase.

X-ray studies revealed the considerable enhancement of metal-binding properties in human hemoglobin under exposure to mild damaging factors (in the presence of 0.09 M urea or upon heating for 30 min at 50 °C). Changes in the element composition of the hemoglobin monolayer, formed on the water subphase in the Langmuir trough, have been monitored in real time by the total external reflection X-ray fluorescence measurements. X-ray absorption spectroscopy has been applied to study the local environment of zinc ions bound on hemoglobin molecules. According to these data, each zinc ion is coordinated by four ligands, two of which are cysteine and histidine. The oxidative stress has been found to accelerate extensively the enhancement of metal-binding ability in protein. A two-stage mechanism has been proposed as a possible explanation of the observed phenomenon: First, in the presence of the mild damaging agents, protein molecules can undergo a transition from the native conformation to a more labile intermediate state that increases the accessibility of amino acid residues (in particular cysteine). At the second stage, oxidation of cysteine and the subsequent activation of cysteine SH groups can affect markedly the protein-metal interaction. The presented investigations provide a deeper insight into the pathogenesis of metabolic disorders that excessive concentrations of the endogenic toxicants might trigger in an organism.

The processes of structural rearrangement in a model membrane, i.e., an arachic acid monolayer formed on a colloidal solution of cerium dioxide or magnetite, are studied in situ in real time by the methods of X-ray standing waves and 2D diffraction. It is shown that the character of the interaction of nanoparticles with the monolayer is determined by their nature and sizes and depends on the conditions of nanoparticle synthesis. In particular, the structure formation in the monolayer–particle system is greatly affected by the stabilizer (citric acid), which is introduced into the colloidal solution during synthesis.

The structure of Langmuir-Blodgett (LB) films formed from solutions of comblike N,N-dimethylhexadecylammonium polyamic-acid salt on the basis of the dianhydride of 3,3′,4,4′-diphenyl-tetracarboxylic acid and o-tolidine is studied by the AFM method. The structural organization of dilute solutions of the amphiphilic polyimide prepolymer in mixed solvents (DMAA-dioxane, DMAA-benzene, and MP-benzene) is studied by the method of polarized light scattering. The statistical structural parameters of the solutions are calculated using Debye-Stein theory. It is shown that the dimensions of ordered scattering formations depend on the chemical nature of the mixed solvent components. The parameters, characterizing the structure of the prepolymer solutions in various solvents, are compared. The dependence of the surface morphology of the LB films on the structural organization of the initial prepolymer solutions is revealed.

This paper presents the results of an investigation into hemoglobin-based protein films that were formed on a liquid surface. X-ray standing wave measurements were performed at the ID 10 beamline of the European Synchrotron Radiation Facility (ESRF) and at the Langmuir station of the Kurchatov Synchrotron Radiation Source. It was found that the ability of the protein to bind metal ions is substantially increased due to the conformational rearrangements of protein macromolecules caused by various damaging effects. The elemental composition of protein preparations, which were isolated from children and adults with chronic metabolic diseases accompanied by endogenous intoxication, was analyzed. The results of the investigations offer evidence that an increase in the ligand-binding properties of the protein molecules, which was observed in model experiments using protein films, is a common trait and corresponds to in vivo processes accompanying metabolic disturbances in the body.

The X-ray standing wave method has been applied to study the formation of protein-lipid film on the water subphase. The influence of different toxic reagents (heavy metals and urea) on protein-lipid interaction in an ordered film of glucose oxidase and behenic acid has been investigated. Analysis of angular dependence of fluorescence yield provided information on molecular arrangement in bioorganic nanosystems on the water surface, where protein and phospholipid molecules were free to move over the water subphase.

It is established that the pharmaceutical compositions xydiphon, medifon, succimer, and EDTA, which are used as complexing agents for accelerating the excretion of heavy metals from human organism, at certain concentrations inhibit enzyme alkaline phosphatase (AP). It is concluded that xydiphon and EDTA have a noticeable effect on AP activity at concentrations over 0.01 mM; medifon and succimer, at concentrations of over 0.3–0.5 mM. The enzyme’s inhibition constants and type of inhibition are determined. Xydiphon is found to manifest the highest affinity to AP (K I = 0.35 mM). It is shown by kinetic analysis that dissociative chemoinactivation of the enzyme takes place under the action of complexing agents. The corresponding kinetic parameters are calculated.

Ordered protein films have been obtained by the adsorption of protein molecules on a Langmuir monolayer, which had previously formed on a silicon substrate, using the Langmuir-Blodgett and molecular self-organization methods. A mixture of cholesterol with dipalmitoylphosphatidylcholine (DPPC) and a polymer—cellulose acetopivalinate—were used as immobilization materials. Protein molecules (catalase and alkaline phosphatase) immobilized on solid substrates have been investigated by atomic force micros-copy. It was shown that the developed combined technique provides a deposition of homogeneous ultrathin protein films with a high degree of filling.

The optical properties and morphology of complexes based on polyaniline (PANI) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), depending on their synthesis conditions, have been characterized by UV-visible spectroscopy and atomic force microscopy. The dependence of the electron absorption spectra of PANI/PAMPS complexes and the surface topography of their films on the initiation way of PANI formation (chemical and enzymatic) and the use of promoters of aniline polymerization has been investigated. The aniline polymerization kinetics with and without polymerization promoters has been studied. All PANI/PAMPS complexes are found to have a nanocomposite time-stable structure.

Protein-lipid films based on the enzyme alkaline phosphatase were subjected to the action of chelating drugs, which are used for accelerating the removal of heavy metals from the human body, and the elemental composition of the resulting films was investigated. Total-reflection X-ray fluorescence measurements were performed at the Berlin Electron Storage Ring Company for Synchrotron Radiation (BESSY) in Germany. A comparative estimation of the protective effect of four drugs (EDTA, succimer, xydiphone, and mediphon) on membrane-bound enzymes damaged by lead ions was made. The changes in the elemental composition of the protein-lipid films caused by high doses of chelating drugs were investigated. It was shown that state-of-the-art X-ray techniques can, in principle, be used to develop new methods for the in vitro evaluation of the efficiency of drugs, providing differential data on their actions.

This paper reports on the results of the investigation of protein films that are based on alkaline phosphatase and glucose oxidase enzymes and formed on the surface of the liquid subphase. The experimental studies have been performed using total external reflection X-ray fluorescence spectrometry at the European Synchrotron Radiation Facility (Grenoble, France). The self-organization processes that occur in protein systems on the surface of the liquid subphase under the conditions where the protein molecules retain their mobility have been investigated using X-ray fluorescence measurements for the first time.

The x-ray standing wave method has been applied to study self-assembling processes in a protein-lipid film formed by injecting the protein-lipid mixture of alkaline phosphatase and phosphatidylinositol under the phospholipid monolayer preliminarily deposited on the water subphase by Langmuir method. X-ray standing wave measurements allowed to determine the composition of the protein-lipid film and to locate ions position in the direction normal to the film surface. The presence of trace Ni contamination incorporated in the protein-lipid film from the water subphase has been established. Numerical analysis of the X-ray standing wave fluorescence data revealed that after injection under the phospholipid monolayer, the protein-lipid mixture separated in a self-assembled manner to layered structure, molecules of alkaline phosphatase arranged themselves into a pure protein layer containing no phospholipid molecules.

The molecular organization in Langmuir–Blodgett films of phospholipids and metallomesogen deposited on silicon has been studied by the X-ray standing-wave method at the synchrotron radiation source BESSY (Germany). Analysis of the experimental data obtained made it possible to determine the composition of the organic multilayer nanosystems and localize the position of metal ions incorporated in organic layers from the aqueous subphase during film deposition.

The structural features of the Fab fragments of monoclonal (Waldenstrom’s disease) immunoglobulin M (IgM) and rheumatoid immunoglobulin M (IgM-RF) were studied by a complex of methods, including small-angle X-ray scattering (SAXS), electron spin resonance (ESR), and mass spectrometry (MS). The Fab-RF fragment was demonstrated to be much more flexible in the region of interdomain contacts, the molecular weights and the shapes of the Fab and Fab-RF macromolecules in solution being only slightly different. According to the ESR data, the rotational correlation time for a spin label introduced into the peptide sequence for Fab is twice as large as that for Fab-RF (21±2 and 11±1 ns, respectively), whereas the molecular weights of these fragments differ by only 0.5% (mass-spectrometric data), which correlates with the results of molecular-shape modeling by small-angle X-ray scattering. The conclusion about the higher flexibility of the Fab-RF fragment contributes to an understanding of the specificity of interactions between the rheumatoid factor and the antigens of the own organism.

The structure and phase composition of ZnS nanoparticles grown under a Langmuir monolayer of zinc arachidate were studied using electron diffraction and high-resolution transmission electron microscopy. Room-temperature cathodoluminescence spectra of obtained samples were measured.

Special features of the formation of PbS nanocrystals in Langmuir-Blodgett (LB) films of lead stearate and behenate under the action of H2S are studied. It is shown that structural transformations in a multilayered LB film can be controlled using electron diffraction patterns of the oblique-texture type and x-ray reflectometry data.

The molecular organization of Langmuir-Blodgett films based on the liquid crystal europium complex has been studied by the X-ray standing-wave method at the synchrotron radiation source BESSY (Germany). Analysis of the experimental data obtained made it possible to determine the composition of the organic multilayer nanosystems and localize the position of metal ions incorporated in organic layers from the aqueous subphase during film deposition. It is shown that, despite the low content of metal ions in the aqueous subphase (no higher than 10−7 mol/l), their incorporation into the Langmuir layer affects the molecular film organization significantly.

X-ray standing wave method has been applied to investigate the molecular organization in Langmuir–Blodgett films of liquid-crystalline lanthanide complex deposited on silicon substrates. The X-ray standing waves measurements were carried out at BESSY II on the beamline KMC-2. Energy spectra of characteristic fluorescence emitted from the samples have been recorded at each point in the X-ray reflectivity curve as the incident angle was scanned through the total external reflection region. The integrated intensity under selected peaks was analyzed as a function of the incident angle. Incorporation of metal ions (Fe, Zn, Cu, Ca) to the Langmuir monolayer from the triply distilled water subphase has been established. Owing to the element selectivity of X-ray standing wave technique the arrangement of several types of metal ions inside the Langmuir–Blodgett films was studied individually. The experimental data revealed that the shape of the fluorescence curves for the contamination metal ions is distinctly different indicating considerable differences in the lateral distribution of these ions in the film. These results may be attributed to the phase separation in Langmuir monolayer of liquid-crystalline lanthanide complex due to the incorporation of metal ions from the water subphase.

The structures have been analyzed of the monolayers of comblike precursor polymers of polyimides and mixed cellulose esters formed at the water/air interface and of the Langmuir-Blodgett films obtained by transfer of these condensed monolayers onto solid substrates. The important factors that ensure the structure control and supramolecular organization of these monolayers and films are established.

The protective effect of the bisphosphonate drug xydiphone (K,Na-ethidronate) on membrane-bound enzyme damaged by lead ions has been studied. A protein/lipid film of Ca-ATPase/phosphatedylethanolamine deposited on a silicon substrate was used as a model system. The position of lead ions within the molecular film before and after the xydiphone treatment was determined using the total-reflection X-ray fluorescence method. This technique is based on the simultaneous measurement of the X-ray reflection and the yield of the fluorescence radiation excited by X-ray inelastic scattering. The possibility of directly locating lead ions is the main advantage of this approach. Xydiphone has been found to effectively eliminate lead ions that have been incorporated into Ca-ATPase molecules during a preliminary incubation in lead acetate solution. The lead ions that were bound at the sites of the Ca-ATPase attachment to the phospholipid monolayer have proved to be inaccessible for xydiphone. A preliminary incubation of Ca-ATPase in the xydiphone solution precluded the incorporation of lead ions into the protein.

Langmuir monolayers of metal-rich phthalocyanines (Pc) and phospholipid at air/water interface have been studied by X-ray total reflection fluorescence at SR beam line ID 10B (ESRF). Experimental fluorescence angular dependences from “heavy” ions of a monolayer alone on water surface modulated by evanescent wave/X-ray standing wave pattern have been detected for the first time, are in good agreement with calculations and provide information about the position of metal ions in organic molecule with respect to water surface.

The data are presented on optimization of cellulose synthesis by Acetobacter xylinum (strain VKM V-880) and the structural characteristics of A. xylinum cellulose gel film synthesized during static cultivation. The structural changes caused by the removal of water from gel films are established and the structural organization of macromolecular chains in cellulose A. xylinum is studied.

X-ray total external reflection fluorescence has been applied to detect an angular dependence of fluorescence yield modulated by evanescent/X-ray standing wave pattern from metal-rich organic monolayer alone on water surface. Theoretical consideration reveals that electric field intensity in a molecular monolayer is completely determined by an area per one molecule value that can be obtained from pressure-area isotherm. This allows getting an ion position inside a monolayer from the corresponding fluorescence angular dependence. The possibilities of the technique have been used at the SR beamline ID10B (ESRF) to characterize Langmuir monolayers of phthalocyanines and cyclolinear polyorganosiloxanes formed on air/water interface.

Possibility of the manufacturing magnetic ultra-thin multilayer films with exactly controlled thickness of separated polymer layers was considered. Magnetic multilayer nanocomposites based on polyelectrolytes have been prepared by alternate layer-by-layer assembly method. They were investigated by optical, magneto-optical and electron microscopy and electron diffraction methods. It is shown that the planar surface charge sign influences on the magnetic layer density.

The conditions of the deposition of the mixed cellulose acetovalerate ester Langmuir–Blodgett (LB) films are studied. The structure of films is examined by X-ray and electron diffraction methods, and atomic force microscopy. It was shown that LB films reveal the Y-type layer structure. A comparison between the macromolecule packing in LB films and macrofilms (bulk) was done. Modeling of the cellulose acetovalerate mono- and multilayer organization on the basis of the π–A isotherms and structural data was realized.

The results of a structural study of CdS and PbS nanocrystals grown from solutions under a Langmuir monolayer of a fatty acid are presented, and the influence of the geometric and stereochemical factors on the mutual orientation of the monolayer and the nanocrystals grown are considered.

The X-ray standing-wave method was applied to study the elemental composition and molecular organization of ordered protein films of alkaline phosphatase exposed to different xenobiotics (drug compounds, lead). Binding of metal ions from triply distilled water to protein molecules has been experimentally observed. Definite differences in the arrangement of impurity metal ions in the films have been established. The considerable enhancement of protein–metal interactions is attributed to partial rearrangement of the protein native structure, induced by xenobiotics.

A current hysteresis is detected in magnetic tunnel junctions of the ferromagnetic metal-nonmagnetic insulator-ferromagnetic metal type. The hysteresis is manifested in the formation of loops on the curves describing the dependence of the current through the junction on the applied voltage, as well as in the nonreproducibility of this dependence. This effect is caused by the influence of the spin-polarized current on the magnetic state of metallic layers: the current leads to a rearrangement of the domain structure under these conditions.

We measured the current-voltage characteristics of magnetic tunnel junctions using novel dielectric materials -diamond-like carbon and polyimide barriers-which have a well-controlled chemical composition. For most of our as grown samples we observed hysteresis loops which were independent of the barrier material chosen. Their non-reproducible shape was dependent on bias and external field. We ascribe the hysteresis to the existence of a dynamic change in the domain magnetization of the electrodes due to a feed-back mechanism between the tunnel current and the magnetic structure. In an external magnetic field the hysteresis loops vanish, and the current-voltage characteristics are reproducible.

The phenomenon of monolayer and Langmuir–Blodgett (LB) film stabilization via interaction with water soluble substrates like polyacrylic acid is studied. Hydrogen bonds (H-bonds) are shown to be responsible for the formation of composite monolayers based on tertiary amines and polyacid. An important influence of the contact time (before the compression) and amine amount spread on the subphase on the monolayer density is shown to be related to the diffusion of the polymer molecules up to the subphase surface. The structure of monolayers is found to depend on the amount of polyacid dissolved in water as well as on the order of introduction of the polymer into the water subphase (before or after compression). Composite monolayers based on the preprepared amine monolayer show the most dense and well aligned structure. This results in the formation of double layered LB films with highly periodic structures where polyacid amine residues are located between thin layers of H-bonded polyacid and aligned normally to the film plane. This binding of monolayers with water soluble polymers seems to be very important for the deposition of monolayers on the solid substrates and LB film preparation particularly when monolayers based on individual compounds cannot be transferred.

A new approach to create mesomorphic ordered systems is discussed. It is based on the idea to use noncovalent interactions in the designing of thermotropic structures by modelling lyotropic liquid crystal (LC) when the water interlayer is changed by appropriate solid substances that are able to interact with the polar part of an amphiphilic molecule without any strong change in the intermolecular interactions between the non-polar tails.

Composite gas-separating membranes were prepared by deposition of multibilayer diacetylene Langmuir-Blodgett (LB) films onto a poly(dimethylsiloxane) membrane. Local measurements of gas permeability with the surface resolution of 0.2 cm2 show that LB modification increases both membrane permeability to O2 and He gases and dispersion of local permeability over the membrane surface. A poly (diacetylene) LB film increases the selectivity of O 2 N 2 and He N 2 separation by 1.5 and 1.2 times, respectively. The potential of LB films in the improvement of gas separation is discussed.

The process of multilayer assembly via layer-by-layer deposition of linear polyions and lysozyme have been studied. The films were fabricated on glass slides by alternate electrostatic adsorption of anionic poly(styrenesulfonate) (PSS), cationic poly(allylamine) (PAA) polyions and hen egg-white lysozyme. The multilayer build-up was monitored by the small-angle X-ray diffraction method. X-ray reflectivity curves from the films measured at different steps of the assembly reveal Kiessig fringes. From their periodicity the film thickness was calculated. The growth step for a PSS/PAA bilayer equals 37 A. The thickness of the lysozyme layer equals 45 A, which is close to dimensions of the lysozyme molecule determined by X-ray crystallography. An analysis of surface charges of the lysozyme molecule shows some preferentially positive charged regions, which are the most probable sites of interactions with negatively charged PSS.

The variation of the structural characteristics in the transition from a block polymer to a Langmuir-Blodgett film has been investigated for cellulose acetomyristinate by the methods of X-ray diffraction analysis. The effect of length and number of acid residues on the diffraction pattern of block cellulose acetomyristinate is studied. The role of acyl substituent in the formation of an ordered structure of multilayer Langmuir-Blodgett films is established. A model of packing of cellulose acetomyristinate molecules in the Y-type films is suggested. The model is based on a two-domain structure in which close-packed myristic-acid residues are located either normally or at a certain angle to the plane of glucoside rings on one side of the polymer chain.