The properties of single-component Langmuir monolayers based on 10,12-pentacosadiynoic acid (PCDA) and films formed by its photopolymerization (polyPCDA) have been compared with analogous monolayers and polymer films based on the mixture of PCDA and a boron difluoride complex with hemicurcuminoid (CurBF2). Structural, morphological, and optical properties of both systems are investigated using Langmuir monolayer compression isotherms, atomic force microscopy (AFM), Brewster angle microscopy, UV-Vis spectroscopy, fluorescence spectroscopy, and fluorescence microscopy. It was discovered that presence of the CurBF2 complex in the system profoundly influences the film morphology and its optical properties. Furthermore, CurBF2 substantially lowers the activation barrier for polymerization at the air-water interface. This study demonstrates that the structural and chromatic characteristics of planar polyPCDA polymer assemblies are significantly altered by the incorporation of the CurBF2 complex into the polymer structure. This results in the emergence of novel morphologies and unique optical properties and opens up prospects for improving the functional characteristics of the mixed system. In particular, the mixed film exhibits synergistically enhanced fluorescent response to Pb2+ compared to polyPCDA itself. Moreover, the revealed effect of CurBF2 on the above properties of the mixed films allows monitoring the fluorescence response to lead ions through two fluorescence channels.

Self-assembly into tubular structures typically proceeds by helical winding of ribbon intermediates, however, only the central parts of the tubes, that retain no information on the ribbon geometry, have received attention so far. We propose the procedure of establishing the crystal structure of ribbons and ribbon-based tubes on the basis of crystallographic analysis of the tube-end geometry, where the terminal parts of the ribbons fold and form characteristic mono/bilayer polygonal shapes. The terminal parts of flattened J-aggregate nanotubes of trimethine cyanine dye were clearly resolved in electron microscopy and atomic force microscopy images, and the original parallelogram shape of ribbons was reconstructed and interpreted as a two-dimensional [1-10]/[010] facetted crystal with inclined molecular pi-stacks parallel to the long ribbon side. The back-reconstructed molecular orientations in a tube wall tend to be close to the tube normal. A two-stage "nucleation and growth" type model of the ribbon to tube transition is proposed that takes into account the established ribbon mechanical asymmetry. The model includes closure of the single ribbon loop as a nucleation event and explains, mostly observed in experiments, nearly rectangular shapes of tubes by the transition kinetics. Due to its universal character, the suggested approach can be applied to any ribbon-based tubes, regardless of their chemical composition.

The immobilization of N,N-diallyl-N,N-dimethylammonium chloride (DADMAC) on low-density polyethylene (LDPE) films was carried out by the method of postradiation grafting using x-ray radiation. The introduction of polycation exchanger links provided the appearance of hydrophilicity of the surface of the modified film. By measuring the wetting contact angle, IR and SEM, the island-type character of the coating from grafted polyDADMAC was detected. The death of Gram-negative bacteria Pseudomonas aeruginosa, Gram-positive bacteria Staphylococcus aureus, and yeast (eukaryotes) Yarrowia lipolytica on the surface of the film with grafted polyDADMAC was demonstrated.

The structures of J -aggregates of two monomethine dyes are compared at the meso- and nanoscale by using fluorescence and atomic force microscopy. The J -aggregates of the two dyes are found to have solely a monolayer structure and to be polymorphic. Morphologically, monolayers represent narrow skew-symmetric strips and symmetric rhombi in the case of the first and the second dyes. The second morphological type is the tubular type in both cases. For monolayers of both dyes, atomic force microscopy imaging at the ultimate resolution reveals the presence of a quasi-one-dimensional substructure consisting of densely packed nanostrips with a width in the range of 7–10 nm. The nanostrips are interpreted as building blocks emerging at early stages of monolayer crystallization that proceeds via a nonclassical multistep mechanism.

The effect of addition of J -aggregates of polymethine dye into the hole-transport layer of an organic light-emitting diode (OLED) on its characteristics and operational stability was studied. Water-soluble PEDOT:PSS (poly(3,4-ethylenedioxythiophene)) and the interpolymer complex of polyaniline and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAn-PAMPSA) were used as the matrices of polymer nanocomposites. The highest efficiency characteristics of the OLEDs with the considered structure were achieved using PAn-PAMPSA at a particular component ratio in the interpolymer complex. Additives of J ‑aggregates did not significantly affect the efficiency characteristics of the OLEDs; however, an increase in the operational stability of devices was recorded.

A current-driven source of long-range surface plasmons (LRSPs) on a duplex metal nanolayer is reported. Electrical excitation of LRSPs was experimentally observed in a planar structure, where an organic light-emitting film was sandwiched between two metal nanolayers that served as electrodes. To achieve the LRSP propagation in these metal nanolayers at the interface with air, the light-emitting structure was bordered by a one-dimensional photonic crystal (PC) on the other side. The dispersion of the light emitted by such a hybrid PC/organic-light-emitting-diode structure (PC/OLED) comprising two thin metal electrodes was obtained, with a clearly identified LRSP resonance peak.

Abstract—J-aggregates of a carbocyanine dye (pyridinium salt of 3,3'-di-(γ-sulfopropyl)-4,5,4',5'-di(tieno-3'',2'')-9‑ethyl-tiatrimethine cyanine betaine) (CC) were studied via the high-resolution AFM method at the mesoscale and nanoscale. They were found to exist in two structurally different polymorphic forms of single layers and fibrils. The class of single-layer J-aggregates consists of irregular micron sheets and giant submicron tubes, whose structure is identical to tubular J-aggregates of other cyanine dyes. The fibrillar J-aggregates are composed of 3-nm-high fibrils forming the networks owing to merging and branching, as well as of “elementary” fibrils with a height close to the molecular sizes of dye. Structural models of elementary fibril with molecular “staircase” and “ladder” stacking types were proposed as well.

A crystallographic analysis of the images of destruction fragments of tubular monomethine dye J -aggregates has been performed for the first time. It is shown that the formation of characteristic zigzag fragments is caused by the unwrapping of cylindrical surface on plane. Possible cleavage directions for the monolayer forming the tube walls are considered and an interrelation between the destruction products and molecular packing of this monolayer is established.

The irregular one-dimensional substructure of cyanine dye J-aggregate monolayers resolved by high-resolution atomic force microscopy is inherited from the first stages of multi-stage monolayer crystallization.

Cationic polymers with NH2-groups were used for modification of charged and uncharged surfaces of planar slides, wells of plates, and spherical nanoparticles. Our study was aimed at development of a simple functionalization method of plain surfaces and colloids of different chemical compositions for adhesion of native biopolymers, including proteins, and viable bacterial and eukaryotic cells. Poly(allylamine)s (pAA) and polylysines (pLys) of different molecular weights spontaneously formed interfaces convenient for adhesion of biopolymers and cells. Thickness of the pAA 65 kDa layer similar to 1.5-2 nm was measured by two methods: 1) atomic force microscopy (AFM) on mica slides and 2) registration of the long range surface optical waves excitation angle and the critical angle of total internal reflection from the liquid on a photonic crystal surface by using the biosensor. The sorption capacity of 0.1 mg/ml pAA 65 kDa exceeded the values of other polyamines at different concentrations. Physisorption of proteins on pAA layer was reversible and up to 70% of attached proteins could be removed by subsequent washes. Additional treatment with glutaraldehyde (GA) provided stable chemical cross-linking of the compounds containing primary NH2-groups with aminated surfaces. The proteins immobilized on the pAA-covered surface retained their ability to bind with specific monoclonal and polyclonal antibodies. Bacterial cells after adhesion on pAA65-covered surfaces maintained their morphology, could reproduce and express the green fluorescent protein (gfp) gene under control of the inducible lac promoter. Eukaryotic cells of human and mammalian origin also remained viable on pAA-treated slides as proven by their staining with fluorescent dyes and cell divisions until confluent monolayers. Mammalian cells could not attach onto silicon wafers but grew on pAA interface of the silicon slides until confluent monolayers. Thus, surface modification with polyallylamines provides adhesion of native biopolymers and living cells.

The molecular orientation in monolayer J-aggregates of 3,3-di(γ-sulfopropyl)-5,5-dichlorotiamonomethinecyanine dye has been precisely estimated using improved linear polarization measurements in the fluorescence microscope in which a multiangle set of polarization data is obtained using sample rotation. The estimated molecular orientation supplemented with the previously established crystallographic constraints based on the analysis of the well-developed two-dimensional J-aggregate shapes unambiguously indicate the staircase type of molecular arrangement for striplike J-aggregates with the staircases oriented along strips. The molecular transition dipoles are inclined at an angle of ∼25° to the strip direction, whereas the characteristic strip vertex angle ∼45° is formed by the [100] and [1-10] directions of the monoclinic unit cell. Measurements of the geometry of partially unwound tubes and their polarization properties support the model of tube formation by close-packed helical winding of flexible monolayer strips. In the tubes, the long molecular axes are oriented at a small angle in the range of 5-15° to the normal to the tube axis providing low bending energy. At a nanoscale, high-resolution atomic force microscopy imaging of J-aggregate monolayers reveals a complex quasi-one-dimensional organization.

In this article the results from studies of liposomes with the inclusion of active pharmacological substances (irinotecan, oxaliplatin, cytochrome C, doxorubicin, quercetine, etc.) in lipid nanoparticles are introduced. The key techniques of adding substances to liposomes are observed: the lipid-film method and the gradient and chemical-bond methods. The main conditions for the inclusion of drugs in liposomes are presented. Questions of determining the inclusion in liposomes and the synthesis and control of the liposomal drugs are discussed. The synthesized drugs are currently undergoing preclinical and clinical trials. Some of the proposed drugs have already been registered and have been used in medical practice for more than 25 years.

В статье приведены результаты исследования включения в липидные наночастицы — липосомы фармацевтически активных субстанций (иринотекана, оксалиплатина, цитохрома С, доксорубицина, кверцетина и др.). Рассмотрены основные методы включения субстанций в липосомы: метод липидной пленки, методы градиента и химической связи. Приведены основные условия включения лекарственных веществ в липосомы. Обсуждаются вопросы определения включения в липосомы, получения и контроля готовых лекарственных липосомальных препаратов. Полученные препараты находятся на различных стадиях доклинических и клинических испытаний. Ряд предложенных препаратов зарегистрирован и используются в медицинской практике более 25 лет.

Meso- and nanoscale structural polymorphism of monolayer J-aggregates of four cyanine dyes are investigated. Three mesoscale morphological types are observed: ribbons, rhombic leaves, and tubes. Tubes are formed during cylindrical spinning of ribbons. Lined substructure characterized by the line width of about 7 nm is found in the case of monolayers of monomethine cyanine dyes at the nanoscale.

Different graphitic materials are either already used or believed to be advantageous in biomedical and biotechnological applications, e.g., as biomaterials or substrates for sensors. Most of these applications or associated important issues, such as biocompatibility, address the problem of adsorption of protein molecules and, in particular the conformational state of the adsorbed protein molecule on graphite. High-resolution AFM demonstrates highly oriented pyrolytic graphite (HOPG) induced denaturation of four proteins of blood plasma, such as ferritin, fibrinogen, human serum albumin (HSA) and immunoglobulin G (IgG), at a single molecule level. Protein denaturation is accompanied by the decrease of the heights of protein globules and spreading of the denatured protein fraction on the surface. In contrast, the modification of HOPG with the amphiphilic oligoglycine-hydrocarbon derivative monolayer preserves the native-like conformation and provides even more mild conditions for the protein adsorption than typically used mica. Protein unfolding on HOPG may have universal character for "soft" globular proteins.

Magnetic properties of inhomogeneous nanoisland FeNi films were studied by SQUID magnetometry. The FeNi films with nominal thickness ranging from 0.6 to 2.0 nm were deposited by rf sputtering on Sitall glass substrates and covered by a protecting Al2O3 layer on the top. The SQUID data indicate pronounced irreversibility behavior for the out-of-plane temperature-dependent magnetization response (measured at H≃100 Oe) using zero-field cooling (ZFC) and field-cooled warming (FCW) after the applied dc magnetizing field Hm≃2 T for the FeNi samples with nominal thickness 1.1 nm ≲d≲1.8 nm, below the percolation threshold. The positive difference between the FCW and ZFC data identifies two irreversibility temperature scales, TB≈50 K and T⁎≈200 K, which can be associated with the superparamagnetic and superferromagnetic behavior in inhomogeneous nanoisland FeNi films, respectively. However, above the film percolation threshold, we observed a crossover from the out-of-plane to in-plane magnetization orientation. Here, the in-plane FCW-ZFC difference implies negative remanent magnetization response in the temperature range TB≲T≲T⁎. The observed magnetization properties can be associated with the presence of the superferromagnetic phase in self-assembled clusters of quasi-2D metallic magnetic FeNi nanoislands.

It is shown that the introduction into the aqueous solution of anionic thiamonomethinecyanine of the Mg2+ cation promotes the formation of the multilayer dye J-aggregates. It is also established that, on the J-aggregates or on the metallocomplex J-aggregates of anionic thiamonomethinecyanine, a multilayer and simultaneously multichrome system of new J-aggregate is formed due to the additional introduction of cationic cyanine dye into the solution, which absorbs light in a different region of the spectrum than anionic dye.