1. Name：Compression Isotherms of Polydopamine Films
Authors：O. Yu. Milyaev, A. V. Akent’ev, A. G. Bykov, A. V. Zerov, N. A. Isakov, and B. A. Noskova
Abstract：Polydopamine is formed via dopamine hydrochloride (DAH) polymerization in a slightly alkalinemedium (pH 8.5) both in a solution bulk and at a liquid–gas interface. Atmospheric oxygen and oxygen dissolvedin the bulk solution serves as an oxidizing agent. Compression isotherms of polydopamine filmsformed at the interface for different times at different initial DAH concentrations have been determined inthis work. Initial concentration of DAH affects the rate of polydopamine film formation; however, it weaklyaffects the film structure. At a low DAH concentration (1 g/L) and a long surface lifetime (720 min), thecompression isotherms and the dependences of the static surface elasticity on the surface pressure turn out tobe close to corresponding dependences for polydopamine films formed at a relatively high DAH concentration(5 g/L) and a shorter surface lifetime (240 min). The dependences of the static surface elasticity on thesurface pressure appear to be nonmonotonic in contrast to the corresponding dependences of dynamic surfaceelasticity. In the first case, significantly higher values of the surface pressure are achieved; however, inthe region of low surface pressures (<7 mN/m), the results are close to each other. The maximum static surfaceelasticity for continuous uniform polydopamine films is 150 mN/m. Upon a further compression, suchfilms begin to collapse with the formation of a three-dimensional multilayer structure.
2. Name：Interaction of chlorogenic acid with model lipid membranes and its influence on antiradical activity
Authors：J.P. Cejas, A.S. Rosa, M.A. Nazareno, E.A. Disalvo, M.A. Frias
Journal：BBA – Biomembranes
Abstract：Chlorogenic acid (CGA) is a strong phenolic antioxidant with antibacterial properties composed by a caffeoylester of quinic acid. Although a number of benefits has been reported and related to interactions with the redblood cell membranes, details on its membrane action and how composition and membrane state may affect it, isnot yet well defined.In this work, the interaction of CGA with lipid monolayers and bilayers composed by 1,2-dimiristoyl-snglycero-3-phosphocholine (DMPC); 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (14:0 diether PC); 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-di-O-hexadecyl-sn-glycero-3-phosphocholine (16:0diether PC) were studied at different surface pressures (π). The kinetics of interaction was found to be more rapidin DMPC than in the absence of carbonyl groups. Measurements by FTIR-ATR at different water activities confirmspecific interactions of CGA with carbonyl and phosphate groups affecting water level along hydrocarbon region.The antioxidant activity of CGA in the presence of DMPC unilamellar vesicles, evidenced by the absorbancereduction of the radical cation ABTS•+, is significantly different with respect to aqueous solution. The influenceof CGA on antiradical activity (ARA) with lipid membranes depending on the hydration state of the lipidinterface is discussed.
3. Name：Langmuir layers of fullerene C60 and its mixtures with amphiphilic polymers
Authors：Boris A. Noskov, Kirill A. Timoshen, Alexey G. Bykov
Journal：Journal of Molecular Liquids
Abstract：The application of dilational surface rheology and optical microscopy combined with the moreconventional methods of surface tensiometry, ellipsometry and atomic force microscopy showsthat the properties of mixed spread layers of fullerene C60 with poly(vinylpyrrolidone) (PVP) andpoly(N-isopropylacrylamide) (PNIPAM) are determined by the polymer at low surface pressures(less than the maximum value for a pure polymer monolayer) and by the fullerene at highersurface pressures. In particular, the dependences of the dynamic surface elasticity on the surfacepressure for the mixed layers have two local maxima corresponding to the polymer and fullerene.These results indicate that the layer consists of two separate phases at low surface pressuresbelow the characteristic value of the polymer displacement from the interface. Although thecollapse of the fullerene layers starts at surface pressures of far less than 70 mN/m, some patchesof the layers sustain surface pressures up to this value. The high stability of the fullerene spreadlayer and its strong adhesion to water can be explained by the hydroxylation of the fullerenemolecules where they contact the water. A similar explanation of the high stability of fullereneaggregates in bulk water has been proposed recently. The fullerene layer is heterogeneous andconsists mainly of surface aggregates with dimensions of approximately 40 – 60 nm in the X-Yplane. The local folding of the layer of these aggregates at high surface pressures (> 30 mN/m)leads to the striation patterns, which are typical for the collapse of nanoparticle monolayers.
4. Name：The effect of acyl chain length and saturation on the interactions of pirarubicin with phosphatidylethanolamines in 2D model urothelial cancer cell membranes
Authors：Dorota Matyszewska ⁎, Angelika Jocek
Journal：Journal of Molecular Liquids
Abstract：The interactions of an anticancer drug pirarubicin (THP) with a series of phosphatidylethanolamine (PE) lipidsdiffering in the length and unsaturation degree of acyl chains were investigated using the Langmuir techniquesupplemented with Brewster angle microscopy (BAM) and thermodynamic analysis of compression-expansioncycles. The incorporation of the drug from the subphase into the lipid monolayer treated as a simple model ofurothelial cancer cell membranes leads to the increase in the areas per molecule at lower surface pressures,while further compression of the monolayer at the air-water interface results in the expulsion of the drug. Inthe case of 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine (DMPE) undergoing liquid expanded – liquidcondensed (LE-LC) phase transition the isotherms in the presence and absence of THP are essentially indiscernibleat higher surface pressures and the drug was found to locate in between the domains. For other lipids (1,2-distearoyl-sn-glycero-3-phosphoethanolamine, DSPE, 1-stearoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine,SOPE and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine, DOPE) the isotherms recorded in the presence ofTHP were characterized by areas per molecule smaller than those for the isotherms obtained for lipids on apure buffer. It shows that the drug, despite squeezing out from the lipid monolayer, is still interacting stronglywith lipid molecules. The formation of THP/lipid aggregates takes place as shown by the results of the thermodynamicanalysis for the compression-expansion cycles. It may explain a disruptive effect of THP on the lipid packing,which is supported by a decreased value of Cs−1max. The most significant interactions were observed for 1,2-dilinoleoyl-sn-glycero-3-phosphoethanolamine (DLOPE). Due to the tilt of the acyl chains caused by the presenceof two double bonds in each chain, a pocket is formed allowing THP to effectively penetrate the hydrophobic partof the DLOPE monolayer even at higher surface pressures without squeezing-out effect. Interestingly, this penetrationis not accompanied by any formation of lipid-drug aggregates as shown by thermodynamic analysis ofhysteresis. Moreover, THP is also able to effectively incorporate into the preformed DLOPE layers. These resultsare important for the detailed explanation of the molecular mechanisms of the passive transport of THP throughthe urothelial cancer cell membranes, which are especially enriched in the longer chain, double unsaturated PElipids such as DLOPE.
5. Name：Properties of DNA-CTMA monolayers obtained by Langmuir-Blodgett technique
Authors：Aleksandra Radko, Jacek Nizioł b, Katarzyna Makyła-Juzak , Robert Ekiert , Natalia G´orska, Andrzej G´orecki, Monika Marzec
Journal：Materials Science & Engineering B
Abstract：The complex consisting of DNA and cetyltrimethylammonium chloride (DNA-CTMA) is extensively exploited inorganic electronics in form of thin films with submicron or nanometer thickness. In this work, using theLangmuir-Blodgett technique, the surface films were prepared from complexes based on different types ofchromosomal and plasmid DNA. The research focused on changes in their continuity after they were transferredonto a solid substrate. It was found that only the monolayer of plasmid DNA-CTMA complex remained continuousafter being transferred. The other complexes underwent a spontaneous self-assembling and created elongatedlinear patterns. AFM images of these patterns were analysed quantitatively with Fast Fourier Transform. Itwas confirmed that self-assembling occurred along one privileged direction.
6. Name：Physicochemical and Biological Characterization of Novel Membrane-Active Cationic Lipopeptides with Antimicrobial Properties
Authors：Joanna Juhaniewicz-Dębińska, Robert Lasek, Dagmara Tymecka, Kinga Burdach, Dariusz Bartosik,and Sławomir Sęk
Abstract：We have designed and synthesized new shortlipopeptides composed of tetrapeptide conjugated to fatty acidswith different chain lengths. The amino acid sequence of thepeptide moiety included D-phenylalanine, two residues of L-2,4-diaminobutyric acid and L-leucine. To explore the possiblemechanism of lipopeptide action, we have provided a physicochemicalcharacterization of their interactions with artificial lipidmembranes. For this purpose, we have used monolayers andbilayers composed of lipids representative of Gram-negative andGram-positive bacterial membranes. Using surface pressuremeasurements and atomic force microscopy, we were able to monitor the changes occurring within the films upon exposure tolipopeptides. Our experiments revealed that all lipopeptides can penetrate the lipid membranes and affect their molecular ordering.The latter results in membrane thinning and fluidization. However, the effect is stronger in the lipid films mimicking Gram-positivebacterial membranes. The results of the physicochemical characterization were compared with the biological activity of lipopeptides.The effect of lipopeptides on bacterial growth was tested on several strains of bacteria. It was revealed that lipopeptides showstronger antimicrobial activity against Gram-positive bacteria. At the same time, all tested compounds display relatively lowhemolytic activity.
7. Name：High Axial and Lateral Resolutions on Self-Assembled Gold Nanoparticle Metasurfaces for Live-Cell Imaging
Authors：Shihomi Masuda, Thasaneeya Kuboki, Satoru Kidoaki, Shi Ting Lee, Sou Ryuzaki, Koichi Okamoto,Yusuke Arima, and Kaoru Tamada
Abstract：A plasmonic metasurface composed of homogeneously self-assembled goldnanoparticles can provide high-contrast fluorescence images confined to the nanointerface. Inthis study, we successfully demonstrated real-time, high-spatiotemporal-resolution imaging ofadhered Venus-paxillin-3T3 live cells under a widefield microscope, where not only a high axialresolution but also a high lateral resolution down to the theoretical limit were confirmedthrough nascent cluster formation of paxillin. The improved lateral resolution on the sheetcould be interpreted as the characteristic of localized surface plasmon resonance (LSPR)-mediated enhanced fluorescence and the metasurface acting as a nanothickness plane lightemitter. We also found minimized photobleaching, owing to the increase in the emissionefficiency via plasmon-exciton coupling. This simple nanomaterial-based technique will be apowerful tool to enhance interfacial signals and improve the quality of live-cell images, not onlyunder widefield microscopes but also in combination with various super-resolution microscopesystems in the future.
8. Name：Difference in lipid cell composition and shaped-based gold nanoparticles induce distinguish pathways in Langmuir monolayers response
Authors：J. Cancino-Bernardi , P.M.P. Lins, V.S. Marangoni, H.A.M. Faria, V. Zucolotto
Abstract：Understanding the interactions occurring at the nano-bio interface is still a challenge. This study presents aninvestigation on the interactions between natural cell membranes and gold-based particles that were isolatedfrom real – cancer and health – cells and reconstructed as monolayers. The influence of the morphology andsurface charge of gold nanomaterials on the membrane structure, as well as the interface properties of themembranes was evaluated. Our results revealed that the interaction pathway of nanoparticles through the cellmembrane was affected by the lipidic composition of each cell type evaluated. Moreover, we show that thesurface charge of the nanoparticles plays a significant role in their ability to interact with cell membranes, asrevealed by isothermal titration calorimetry, and atomic force microscopy analysis.
9. Name：Evolution of transparent graphene oxide thin films synthesized using Langmuir-Blodgett technique
Authors：Amanpreet Kaur, Shivani Goyal and Loveleen K. Brar
Journal：AIP Conference Proceedings
Abstract：In this work uniform, transparent thin films of Graphene Oxide (GO) of variable thickness have been preparedusing Langmuir Blodgett (LB) deposition process. Surface pressure-area isotherms and hysteresis measurements havebeen used to characterize the GO Langmuir thin films on the water sub-phase prior to transfer onto solid substrate todetermine the suitable deposition parameters. AFM analysis of the deposited films (1,2,4 and 5 layers) shows that thefilms are continuous and smooth (low r.m.s. roughness). The roughness of the films increases with increasing number oftransferred layers and smoother films are obtained for higher barrier compression rates.
10. Name：Topographical evolution of multilayerPVDF thin films deposited using Langmuir Blodgett technique
Authors：Kaveri Ajravat and Loveleen K. Brar
Journal：AIP Conference Proceedings
Abstract：Polyvinylidene Fluoride (PVDF) is a promising homopolymer for a wide range of thin film applications due to thepyroelectric, ferroelectric and piezoelectric properties of its β-phase crystal structure. In the present work, the thin films of PVDFare prepared by Langmuir-Blodgett (LB) technique which allows for unique control of the film fabrication parameters. TheLangmuir monolayers before the LB deposition are prepared by using N-methyl-2-pyrrolidone (NMP, a dipolar aprotic solvent)as the spreading solvent. The isotherm, hysteresis and barrier oscillation experiments for the PVDF Langmuir monolayers showthat the most stable PVDF films were obtained for a spreading solution molarity of 0.0936 mol/l and 20 mm/min compressionrate. Multilayer PVDF Langmuir Blodgett thin filmsare deposited on glass substrate with good transfer ratio. The topographicalevolution of the films with successive layer deposition is characterized using AFM.
11. Name：Low temperature processable crystalline WO3 Langmuir-Blodgett ultra-thin film as blocking layer in solar cells application
Authors：Rohan Mewada, Navjyoti, Vibha Saxena, Sipra Choudhury, Aman Mahajan, Ajay Singh, and K.P. Muthe
Journal：AIP Conference Proceedings
Abstract：A key to achieve high efficiency in solar cells is to have charge extraction layer with proper energy levels. Thislayer selectively extracts electrons (or holes) whilst blocking the hole (or electron) and therefore help in reducing therecombination at various interfaces. Conventionally, WO3 is used as a hole-transport and electron-blocking layer inperovskite and polymer solar cells owing to high work function and carrier mobility and excellent thermal stability. Inthis paper, we report preparation of crystalline ultra-thin WO3 films at low temperature and its application as electrontransportand hole blocking layer (BL). For this purpose, WO3-octadecyl amine (ODA) multilayers were prepared byLangmuir-Blodgett (LB) technique and decomposed by UV-ozone treatment. The films were annealed at differenttemperatures in order to improve the crystallinity. The conversion of WO3-ODA complex (WO3-ODA) in WO3 wasconfirmed from X-ray photoelectron spectroscopy (XPS), Fourier Transform infrared spectroscopy (FTIR) and Ramanspectroscopy. Films were further characterized using electrochemical technique in order to assess their blockingproperties. Excellent blocking behavior observed for prepared WO3 films suggest their suitability as BL in solar cellapplication. The WO3 films, when employed as BL in dye sensitized solar cells (DSSC), were found to improveefficiency as well as short-circuit current density (Jsc) and open-circuit potential (Voc) in comparison with DSSCsfabricated using conventionally prepared TiO2 BL. The analyses of obtained results suggest that the WO3 film preparedby LB technique can be a potential blocking layer for DSSC and perovskite solar cells.
12. Name：Amyloid Formation by Short Peptides in the Presence of Dipalmitoylphosphatidylcholine Membranes
Authors：Barbara B. Gerbelli, Cristiano L. P. Oliveira, Emerson R. Silva, Ian W. Hamley, and Wendel A. Alves
Abstract：The aggregation of two short peptides, [RF] and [RF]4(where R = arginine and F = phenylalanine), at dipalmitoylphosphatidylcholine(DPPC) model membranes was investigated at the air−water interface using the Langmuir technique and vesicles in aqueoussolutions. The molar ratio of the peptide and lipid components wasvaried to provide insights into the peptide−membrane interactions,which might be related to their cytotoxicity. Both peptides exhibitedaffinity to the DPPC membrane interface and rapidly adopted β-sheetrichstructures upon adsorption onto the surface of the zwitterionicmembrane. Results from adsorption isotherm and small-angle X-rayscattering experiments showed changes in the structural andthermodynamic parameters of the membrane with increasing peptideconcentration. Using atomic force microscopy, we showed theappearance of pores through the bilayer membranes and peptideaggregation at different interfaces, suggesting that the hydrophobic residues might have an effect on both pore size and layerstructure, facilitating the membrane disruption and leading to different cytotoxicity effects.
13. Name：The effect of the substrate surface state on the morphology, topography and tribocorrosion behavior of Si/Zr sol-gel coated 316L stainless steel
Authors：Stephania Kossman , Leonardo Bertolucci Coelho , Alex Montagne , Alberto Mejias , Adrien Van Gorp, Thierry Coorevits , Matthieu Touzin , Marie-Eve Druart , Mariana H. Staia a, Marc Poorteman, Marie-Georges Olivier
Journal：Surface & Coatings Technology
Abstract：In the present work, a Si/Zr based sol–gel (SG) coating was deposited on 316L stainless steel plates, previouslytreated by passivation (SSO) or electropolishing (SSEP) producing two different surface states. The SG coatingswere compared for SSO and SSEP substrates in terms of morphology, topography and tribocorrosion response.The coating topography revealed a smoother surface for the Si/Zr-SSEP system. The coating deposited on thesmoothest surface (Si/Zr-SSEP) presented half of the thickness of the one deposited on the roughest surface (Si/Zr-SSO). Tribocorrosion behavior was studied under potentiostatic control at anodic potential with a continuousrecording of current (I) during sliding (pin-on-disc and alumina ball counterbody). Both SG systems showed anincrease of current upon 100 sliding contact cycles indicating corrosion activity. After tribocorrosion tests, bothsystems revealed scratches, typical of abrasion, and coating removal in the wear tracks; the alumina counterpartspresented accumulation of wear particles adhered to their surfaces. In conclusion, the initial surface state of thesubstrate modified the coating thickness, topography but did not significantly alter the tribocorrosion response of the studied SG systems.