Repositório Institucional - Unifesp :: Navegando por Palavras-chave "Langmuir monolayers"

Navegando por Palavras-chave "Langmuir monolayers"

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Adsorption and enzyme activity of sucrose phosphorylase on lipid Langmuir and Langmuir-Blodgett films
(Elsevier B.V., 2014-04-01) Rocha, Jefferson Muniz [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
The production of bioelectronic devices, including biosensors, can be conducted using enzymes immobilized in ultrathin solid films, for which preserving the enzymatic catalytic activity is crucial for optimal performance. in this sense, nanostructured films that allow for control over molecular architectures are of interest. in this paper, we investigate the adsorption of sucrose phosphorylase onto Langmuir monolayers of the phospholipid dimyristoylphosphatidic acid, which caused the surface pressure isotherms to expand. With polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), the amide bands from the enzyme could be identified, with the C-N and C=O dipole moments lying parallel to the air-water interface. Structuring of the enzyme into an alpha-helix was noted, and this structure was preserved when the mixed enzyme-phospholipid monolayer was transferred in the form of a Langmuir-Blodgett (LB) film. the latter was demonstrated with measurements of the catalytic activity of sucrose phosphorylase, which presented the highest enzyme activity for multilayer LB film. the approach presented in this study not only allows for optimized catalytic activity toward sucrose but also permits to explain why certain film architectures exhibit superior performance. (C) 2014 Elsevier B.V. All rights reserved.
Somente Metadadados
Algal polysaccharides on lipid Langmuir-Blodgett films and molecular effects upon metal ion contact
(Elsevier B.V., 2013-05-01) Brito, Audrey Kalinouski de [UNIFESP]; Caseli, Luciano [UNIFESP]; Nordi, Cristina S. F. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
The capability of extracellular polysaccharides released from microorganisms to bind to metal ions is a potential molecular biotechnological tool to produce biosorbents as an alternative for the removal of heavy metals from aquatic environments. in this paper, we exploit the ability of polysaccharides from extracellular polymeric substances produced by phytoplankton adsorbed on lipid monolayers as Langmuir-Blodgett films to interact with silver ions in aqueous environments. the properties of the biomacromolecules after the interaction were investigated with polarisation modulation infrared reflection-absorption spectroscopy and atomic force microscopy. the vibrational spectroscopy technique applied to the Langmuir-Blodgett films before and after contact with silver ions indicated significant changes for the bands related to the chemical groups present in polypeptides and polysaccharides. These changes point to the influence of the metal interaction on the molecular organisation and on the structure of the Langmuir-Blodgett film. Therefore, the behaviour of these biomacromolecules adsorbed at bioinspired interfaces is better understood in terms of properties at the molecular level. This understanding leads to a model in which metal incorporation affects the molecular structure of the ultrathin film. (C) 2013 Elsevier B.V. All rights reserved.
Acesso aberto (Open Access)
Celulase e álcool desidrogenase imobilizadas em filmes de Langmuir -Blodgett para identificação de celulose e etanol no nível molecular
(Universidade Federal de São Paulo, 2013-01-07) Rodrigues, Dilmer [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
In this study, we investigated at the molecular level the incorporation of cellulase and alcohol dehydrogenase (ADH) in Langmuir and Langmuir-Blodgett (LB) films of dipalmitoylphosphatidylcholine (DPPC). The mixed DPPC-enzyme films were then investigated upon contact with cellulose and ethanol. The changes at the molecular level in the properties of the films were analyzed by optical and tensiometric techniques. We aim to obtain information on the production of ethanol in a more efficient manner. The first evidence that enzymes adsorbed at the films in the lipid-water interface was through adsorption kinetic curves, wherein upon insertion of the enzyme in the aqueous subphase for monolayers of DPPC, an increase in the surface pressure values for the phospholipid matrix was observed. The second evidence was the analysis of the surface pressure-area isotherms, which showed that the presence of the enzymes caused the expansion of the lipid monolayer to higher areas. The third evidence was observed with polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS), studied in Langmuir films, which revealed bands in the regions between 1500 cm-1 and 1800 cm-1, related to protein groups, namely amide II ( CN and NH bendings) and amide I (C = O stretch). In the sequence, the films were transferred to solid matrices as LB films. The PM-IRRAS analysis confirmed the successful transfer of enzyme and phospholipids. The molecular interaction between the mixed LB film (DDPC / ADH / cellulase) and cellulose was observed through PM-IRRAS since in the regions between 1500 cm-1 and 3500 cm-1, changes were observed revealing alterations in the secondary structure of the protein, related to beta-sheet, alpha-helix, beta-turn, and unordered structures. Also for the regions between 2800 cm-1 and 3500 cm-1, the symmetric and asymmetric stretches for CH in CH2 CH3 groups, as well as the stretching of amines (NH2) and OH groups could be investigated. All these factors indicate the sensitivity of the enzymes when placed in contact with cellulose dissolved in ionic liquid.
Somente Metadadados
Chitosan does not inhibit enzymatic action of human pancreatic lipase in Langmuir monolayers of 1,2-didecanoyl-glycerol (DDG)
(Elsevier B.V., 2014-11-01) Souza, Adriano L.; Pavinatto, Felippe J.; Caseli, Luciano [UNIFESP]; Volpati, Diogo; Miranda, Paulo B.; Oliveira, Osvaldo N.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
In this study, we tested the hypothesis according to which chitosan reduces lipid digestion by blocking the access of lipases to ingested fat. Because lipase action takes place mostly at interfaces, we produced Langmuir films of 1,2-didecanoyl-glycerol (DOG), which is the substrate for human pancreatic lipase (HPL). the experimental assays were carried out in acidic medium, at pH 3.0, to ensure that chitosan is completely soluble. Chitosan was found to affect strongly the surface activity of HPL that forms a Gibbs monolayer at the air/water interface, but did not inhibit the enzymatic action of HPL toward the DDG monolayer. the latter was observed using two surface-specific spectroscopic techniques, namely polarization-modulated infrared reflection-absorption and sum-frequency generation (SFG). the extension of DOG hydrolysis calculated using SFG spectroscopy was 33% in the absence of chitosan, and ranged from 29 to 50% in the presence of chitosan at concentrations of 0.20 g L-1 and 0.30g L-1, respectively. Therefore, fat protection by chitosan is unlikely to be an important factor in fat reduction. (C) 2014 Elsevier B.V. All rights reserved.
Somente Metadadados
Chondroitin sulfate interacts mainly with headgroups in phospholipid monolayers
(Elsevier Science Bv, 2016) Ceridorio, Lucineia F. [UNIFESP]; Caseli, Luciano [UNIFESP]; Oliveira, Osvaldo N., Jr.
Sulfated glycosaminoglycans are precursors of the extracellular matrix used to treat diseases related to blood clotting and degenerative joint diseases. These medical applications have been well established, but the mode of action at the molecular level, which depends on the interaction with cell membranes, is not known in detail. In this study, we investigated the interaction between chondroitin sulfate (CS) and phospholipid monolayers that mimic cell membranes. From surface pressure isotherms and polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS), CS was found to interact mainly with the polar groups of dipalmitoyl phosphatidylcholine (DPPC) and dipalmitoyl phosphatidylglycerol (DPPG), with negligible penetration into the hydrophobic tails and only small changes in monolayer elasticity for the packing corresponding to a real cell membrane. The changes in surface pressure and surface potential isotherms depended on CS concentration and on the time allowed for its adsorption onto the monolayer, which points to a dynamic adsorption-desorption process. The charge of the phospholipid was also relevant, since CS induced order into DPPC monolayers while the opposite occurred for DPPG, according to the PM-IRRAS spectra. In summary, interaction with polar groups is responsible for the CS effects on model cell membranes. (C) 2016 Elsevier B.V. All rights reserved.
Somente Metadadados
Comparative study of liponucleosides in Langmuir monolayers as cell membrane models
(Elsevier B.V., 2011-01-01) Montanha, E. A.; Caseli, L. [UNIFESP]; Kaczmarek, O.; Liebscher, J.; Huster, D.; Oliveira, O. N.; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Humboldt Univ; Univ Leipzig
Liponucleosides may assist the anchoring of nucleic acid nitrogen bases into biological membranes for tailored nanobiotechnological applications. To this end precise knowledge about the biophysical and chemical details at the membrane surface is required. in this paper, we used Langmuir monolayers as simplified cell membrane models and studied the insertion of five lipidated nucleosides. These molecules varied in the type of the covalently attached lipid group, the nucleobase, and the number of hydrophobic moieties attached to the nucleoside. All five lipidated nucleosides were found to be surface-active and capable of forming stable monolayers. They could also be incorporated into dipalmitoylphosphatidylcholine (DPPC) monolayers, four of which induced expansion in the surface pressure isotherm and a decrease in the surface compression modulus of DPPC. in contrast, one nucleoside possessing three alkyl chain modifications formed very condensed monolayers and induced film condensation and an increase in the compression modulus for the DPPC monolayer, thus reflecting the importance of the ability of the nucleoside molecules to be arranged in a closely packed manner. the implications of these results lie on the possibility of tuning nucleic acid pairing by modifying structural characteristics of the liponucleosides. (C) 2010 Elsevier B.V. All rights reserved.
Somente Metadadados
Controlling the molecular architecture of lactase immobilized in Langmuir-Blodgett films of phospholipids to modulate the enzyme activity
(Elsevier Science Bv, 2017) Ayoub, Fabio de Paula [UNIFESP]; Caseli, Luciano [UNIFESP]
In this present work, the adsorption of the enzyme lactase onto Langmuir monolayers of the phospholipid dimyristoylphosphatidic acid (DMPA) was investigated and characterized with surface pressure-area isotherms, surface potential-area isotherms and polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS). The adsorption of the enzyme at the air-water interface expanded the lipid monolayer and increased the film compressibility at high surface pressures. Amide bands in the PM-IRRAS spectra were identified, with the C-N and C=O dipole moments lying parallel to the monolayer plane, revealing that the structuring of the enzyme into beta-sheets was kept in the mixed monolayer. The enzyme-lipid films were transferred from the floating monolayer to solid supports as Langmuir-Blodgett (LB) films and characterized with fluorescence spectroscopy and atomic force microscopy. The catalytic activity of the films was measured and compared to the homogenous medium. The enzyme accommodated in the LB films preserved more than 80% of the enzyme activity after 20 days, in contrast for the homogeneous medium, which preserved less than 60% of the enzyme activity. The method presented in this present work not only allows for an enhanced catalytic activity toward lactose, but also can help explain why certain film architectures exhibit better performance. (C) 2016 Elsevier B.V. All rights reserved.
Somente Metadadados
Effect of carrageenans of different chemical structures in biointerfaces: A Langmuir film study
(Elsevier B.V., 2013-11-01) Lopez, Ricardo F. [UNIFESP]; Nobre, Thatyane M.; Accardo, Camila de Melo [UNIFESP]; Pernambuco Filho, Paulo C. [UNIFESP]; Nader, Helena B. [UNIFESP]; Lopes, Carla C. [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
Carrageenans have unique properties in the pharmaceutical and food industries that involve interactions with lipid interfaces, which may be accessed if surface chemistry techniques are employed. the interaction between three different types of carrageenans with dipalmitoylphosphatidylcholine (DPPC) was investigated using Langmuir monolayers as biointerface models. With a combination of data on Surface Pressure-Area Isotherms and Polarization Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS), the effect of different fractions on DPPC monolayers was compared by considering the chemical and structural differences as well as the anticoagulant activity of each fraction. Thus, a model is proposed in which carrageenans can encompass interactions that are maximized due to geometrical adaptations on behalf of the interactions between polysaccharide sulfate groups and lipid polar heads. (C) 2013 Elsevier B.V. All rights reserved.
Restrito
Estudo da interação do deidrodieugenol e derivados com diferentes modelos de membrana
(Universidade Federal de São Paulo, 2022-12-19) Gonçalves, Giulia Elisa Guimarães [UNIFESP]; Caseli, Luciano [UNIFESP]; Lago, João Henrique Ghilardi [UNIFESP]; http://lattes.cnpq.br/2325513222088331; http://lattes.cnpq.br/8929162910172931; http://lattes.cnpq.br/5651118061433378
A doença de Chagas afeta milhares de pessoas ao redor do mundo, e, assim como algumas outras Doenças Tropicais Negligenciadas apresenta um arsenal terapêutico limitado e controverso. Neste trabalho, três compostos foram estudados como tratamentos alternativos para a infecção. Os derivados mono (II) e permetilado (III) do deidrodieugenol (I) foram preparados através de sua metilação para posterior estudo do potencial anti-Trypanosoma cruzi de cada um desses derivados bem como de I. A fim de entender melhor as diferenças apresentadas, interações entre cada composto e moléculas componentes da membrana celular do protozoário foram analisadas através de modelos do tipo filmes de Langmuir. Tal como o composto I, seu derivado monometilado apresentou atividade antiprotozoária frente à tripomastigotas e amastigotas do T. cruzi, destacando-se um expressivo potencial contra a forma intracelular (amastigotas), com valor de CI50 duas vezes menor do que o apresentado para I (valores de CI50 de 15,1 μM para composto I e de 8,2 μM, para II). Quanto ao derivado permetilado, observou-se uma perda da atividade antiparasitária, principalmente no tangente à forma intracelular do parasita. Paralelamente, ambos derivados apresentaram uma diminuição na citotoxicidade em células de mamífero quando comparados a I. Para melhor entender como diferenças na estrutura desses compostos estariam relacionadas as suas atividades antiparasitárias, os ensaios em monocamada de Langmuir foram realizados usando-se os lipídios: dipalmitoilfosfatidilcolina (DPPC), dipalmitoilfosfatidilglicerol (DPPG), dipalmitoilfosfatidiletalanoamina (DPPE) e dipalmitoilfosfatidilserina (DPPS), os quais foram espalhados na interface ar-água e escolhidos como representantes da membrana celular do parasita. As interações a nível molecular foram analisadas por técnicas tensiométricas (curvas de pressão superficial), elétricas (curvas de potencial superficial), reológicas, espectroscópicas (espectroscopia de absorção-reflexão no infravermelho com modulação de polarização: PM-IRRAS), e morfológicas (microscopia no ângulo de Brewster: BAM). As interações mostraram que, enquanto I aparenta uma preferência pela porção polar dos lipídios segundo a espectroscopia no infravermelho, apresentando, inclusive, similaridade nas alterações reológicas observadas para as monocamadas carregadas negativamente; II trouxe mudanças tanto na porção hidrofílica como hidrofóbica dos diferentes fosfolipídios selecionados. E, mostrou também, certa similaridade nos resultados envolvendo DPPE e DPPS em relação ao potencial de superfície; o que poderia estar relacionado a uma predileção deste composto pelo grupamento amina protonada que ambos os lipídios compartilham em suas estruturas. Por sua vez, III causou um efeito de expansão e condensação em todas as monocamadas testadas bem como outras similaridades. O composto III aparentemente não causou alterações significativas nas monocamadas lipídicas. Com isso, os resultados apontam para o fato de que as interações são moduladas pela composição lipídica da monocamada bem como pela hidrofobicidade dos lipídios e compostos. Acredita-se que fenômenos de agregação estejam sendo promovidos pelos compostos, bem como outros reordenamentos moleculares tal qual o deslocamento vertical de moléculas entre diferentes porções do filme. Conclui-se que os resultados obtidos se relacionam com os diferentes potenciais antiparasitários dos compostos e que os ensaios concordam entre si. Dessa forma, espera-se que o presente trabalho possa contribuir com discussões sobre possíveis terapias para a doença de Chagas; aprimorando o desenho de novas moléculas ao se considerar fatores estruturais.
Acesso aberto (Open Access)
Estudo da interação do gama-terpineol em filmes de Langmuir como modelos de membrana
(Universidade Federal de São Paulo, 2021-01-29) Jaroque, Guilherme Nuñez [UNIFESP]; Caseli, Luciano [UNIFESP]; Sartorelli, Patricia [UNIFESP]; http://lattes.cnpq.br/6836392358779448; http://lattes.cnpq.br/8929162910172931; http://lattes.cnpq.br/3306052344968821
This work aimed to study the interaction of γ-terpineol with lipid Langmuir monolayers, which served as a model for cell membranes to analyze the possible biological actions of the compound at the molecular level. The phospholipids used to compose the films were dipalmitoylphosphatidylcholine (DPPC), dipalmitoyl phosphatidylethanolamine (DPPE), pure or mixed with cholesterol or with bacterial peptidoglycan. The lipids were spread on the air-water interface through organic solutions assembling a Langmuir monolayer. The γ-terpineol compound was incorporated in the monolayer by co-spreading it with the lipids. The interfacial films formed at the air-water interface were compressed by movable barriers, reaching surface pressures that approached the viscoelastic and thermodynamic properties of a proteolipid bilayer. The interaction of the drug with the monolayers was analyzed using tensiometric measurements (surface pressure- area isotherms, tensiometric stability, hysteresis assays), Brewster angle microscopy, and polarization-modulation infrared reflection-adsorption spectroscopy. The physicochemical properties obtained by these measurements were analyzed, and the interactions of γ-terpineol with the lipids at the air-water interface were inferred and extrapolated for the action of the compound in related cell membranes.
Acesso aberto (Open Access)
Estudo da interação do poligodial em modelos de membrana de microorganismos
(Universidade Federal de São Paulo, 2018-04-09) Gonçalves, Giulia Elisa Guimarães [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
In this study, polygodial, a natural product belonging to the group of sesquiterpenes, was isolated from hexane extract of leaves of Drimys brasiliensis (Winteraceae). Due to the promising results regarding the antiparasitic potential, we sought to study its interaction with the membrane models through Langmuir monolayers. Tensiometric, spectroscopic and morphological techniques were used to characterize the pure and mixed lipid monolayers. The lipids adopted in this study were choosen because they have different chemical natures, including: DPPC (dipalmitoylphosphatidylcholine), DMPC (dimyristoylphosphatidylcholine), DOPC (dioleoylphosphatidylcholine); DODAB (dioctadecyldimethylammonium bromide); DPPS (dipalmitoylphosphatidylserine); DPPG (dipalmitoylphosphatidylglycerol); DPPE (dipalmitoylphosphatidylalonamine) and cholesterol. The results show that the DPPG monolayer condenses in the presence of the compound, while as other monolayers expand. The presence of the polygodial is able to plot greater instability for a DPPG monolayer - recorded by adsorption kinetics curves and also by its PM-IRRAS spectrum; while, it also brings an apparent stability to the DOPC and cholesterol monolayers. Here, the behavior of some of this monolayers in presence of polygodial isomer(epi-polygodial) was also compared. Spectra in the infrared region allowed us to evaluate the factor “relative intensity”, especially in the bands related to the asymmetric and symmetrical stretches of the methylene group, which are related to a greater or less organization of the monolayer. On the other hand, images of the monolayers by Brewster angle microscopy showed the morphology of the film with the incorporation of the polygodial and epipolygodial. Particularly, there is an increase in the number of domains for DODAB in the presence of polygodial and a different behavior of DPPE monolayer for the two compounds. As conclusion, a presence of a polar head group as well as an unsaturation in the alkyl chain influenced in the intermolecular forces between the polygodial and the lipid monolayer, besides bringing characteristics of greater or lesser fluidity to the monolayer, depending on the lipid. More fluid monolayers, such as DOPC and DODAB, appeared to incorporate the compound better because of more flexible molecular rearrangement. In addition, a change in the configuration of a stereogenic carbon also seems to contribute to changes in the interactions between lipid-compound, being necessary more studies to better clarify the extensions caused by this change.
Acesso aberto (Open Access)
Filmes ultrafinos luminescentes de Acetato de Celulose com complexos de íons Eu3+ E Tb3+ obtidos por Langmuir-Blodgett
(Universidade Federal de São Paulo, 2022-06-20) Figueiredo, Mayara Macedo [UNIFESP]; Molina, Celso [UNIFESP]; Caseli, Luciano [UNIFESP]; http://lattes.cnpq.br/8929162910172931; http://lattes.cnpq.br/3819814458216651; http://lattes.cnpq.br/5976241386554063
A técnica de Langmuir-Blodgett (LB) permite a obtenção de filmes ultrafinos, organizados na forma de mono ou multicamadas a partir da transferência para suportes sólidos de monocamadas de anfifílicos organizados na interface ar-água, com potencial para várias aplicações tais como sondas luminescentes para bioaplicações e camadas ativas em dispositivos emissores de luz. Visando a obtenção de filmes com viés sustentável, foi utilizado neste trabalho um polímero derivado de fonte renovável (acetato de celulose) e que possua alta transparência na região do visível, juntamente com fosfolipídio ácido dimiristoilfosfatídico (DMPA), anfifílico insolúvel em água e formador de filmes de Langmuir. Foram também incorporados os complexos luminescentes Eu(tta)3(H2O)2 e Tb(acac)3(H2O)3. Assim, estudou-se o efeito da incorporação dos complexos, à monocamada mista formada por acetato de celulose e DMPA na interface ar-água. Os filmes de Langmuir foram caracterizados por isotermas de pressão e potencial superficial-área, microscopia no ângulo de Brewster e espectroscopia de absorção-reflexão no infravermelho para investigação das propriedades termodinâmicas, elétricas, morfológicas e estruturais das monocamadas. Os filmes são mais estáveis quando os componentes acetato de celulose e DMPA são misturados previamente e coespalhados na interface ar-água. As monocamadas foram comprimidas lateralmente e transferidas para suportes sólidos pela técnica LB e caracterizados por espectroscopia no infravermelho e de fotoluminescência. Os filmes LB apresentaram luminescência e apresentaram as principais emissões características dos íons Eu3+ e Tb3+ quando excitados via efeito antena. Além disso, parâmetros como tempo de vida do estado excitado foram obtidos, viabilizando os filmes como possível camada ativa para dispositivos emissores de luz.
Somente Metadadados
How the interaction of PVP-stabilized Ag nanoparticles with models of cellular membranes at the air-water interface is modulated by the monolayer composition
(Academic Press Inc Elsevier Science, 2018) Cruz Gomes da Silva, Rafael Leonardo [UNIFESP]; Oliveira da Silva, Heloiza Fernanda; da Silva Gasparotto, Luiz Henrique; Caseli, Luciano [UNIFESP]
The antimicrobial property of silver nanoparticles (AgNPs) is believed to be associated to their interaction with biointerfaces such as microbial cell membranes, encouraging research on the identification of membrane sites capable of AgNPs binding. Although significant progress has been made in that regard, the exact molecular mechanism of action is yet to be fully understood. In this study, AgNPs dispersed in aqueous media and stabilized with polyvinylpyrrolidone were incorporated in Langmuir monolayers of selected lipids that served as cell membrane models. Results from pressure-area isotherms, vibrational spectroscopy and Brewster angle microscopy revealed condensation of glycoside-free lipid monolayers, evidencing that the AgNPs interact mostly with the lipid hydrophilic head groups. In contrast, the monolayers of systems containing glycoside derivatives were found to expand upon AgNPs incorporation, indicating that the glycosidic compounds might facilitate the incorporation of these nanoparticles in cellular membranes. These data can be therefore correlated with the possible toxicity and microbicide effect of AgNPs in lipidic surfaces of mammalian and microbial membranes. (C) 2017 Elsevier Inc. All rights reserved.
Somente Metadadados
Incorporation of bacitracin in Langmuir films of phospholipids at the air-water interface
(Elsevier Science Sa, 2017) Rodrigues, Jefferson Carnevalle [UNIFESP]; Caseli, Luciano [UNIFESP]
Properties of microbicide drugs are believed to be associated to their interactions with biointerfaces such as cell membranes, encouraging research on the identification of membrane sites capable of drug binding. In this study, we investigated the interaction of bacitracin, a known antibiotic peptide, with cell membrane models represented by Langmuir monolayers of selected phospholipids. It is shown that even small amounts of bacitracin affect the surface pressure-area isotherms, as well as the vibrational spectra and the morphology of phospholipid monolayers, which points to a specific interaction for each phospholipid. Such effects depend on the chemical nature of the monolayer-forming molecules, with the drug activity being distinctive for dipalmitoyl-sn-glycero-3-phospho-L-serine sodium salt in contrast to what was observed for 1,2-dipalmitoyl-sn-glycero-3phospho-L-choline and 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) sodium salt. As a result, the phospholipid composition of the monolayer modulates the interaction with the peptide, which may have important implications in understanding how the drug acts on specific sites of cell membranes. (C) 2016 Elsevier B.V. All rights reserved.
Somente Metadadados
Interaction of 3 ',4 ',6 '-trimyristoyl-uridine derivative as potential anticancer drug with phospholipids of tumorigenic and non-tumorigenic cells
(Elsevier Science Bv, 2017) Grosso Salis, Luiz Fernando [UNIFESP]; Jaroque, Guilherme Nunez [UNIFESP]; Berrio Escobar, Jhon Fernando; Giordani, Cristiano; Martinez Martinez, Alejandro; Marquez Fernandez, Diana Margarita; Castelli, Francesco; Sarpietro, Maria Grazia; Caseli, Luciano [UNIFESP]
Investigating the mechanism of action of drugs whose pharmaceutical activity is associated with cell membranes is fundamental to comprehending the biochemical and biophysical processes that occur on membrane surfaces. In this work, we investigated the interaction of an ester-type derivative of uridine, 3',4',6'-trimyristoyl uridine, with models for cell membranes formed by lipid monolayers at the air-water interface. For that, selected lipids have been chosen in order to mimic tumorigenic and non-tumorigenic cells. For mixed monolayers with 2-dipalmitoyl-sn-g/ycero-3-phosphocholine (DPPC) or l,2-dihexadecanoyl-sn-g/ycero-3-phospho-L-serine (DPPS), the surface pressure-area isotherms exhibited a noticeable shift to lower areas in relation to the areas predicted for ideal mixtures, indicating a condensation of the monolayer structure. Changes in the viscoelastic properties of the interfacial film could be inferred by analyzing the compressibility modulus of the monolayer. Structural and morpho-logical changes were also evidenced by using vibrational spectroscopy and Brewster angle microscopy, respectively, with distinctive effects on DPPC and DPPS. As conclusion we can state that the lipid compo sition of the monolayer modulates the interaction with this lipophilic drug, which may have important implications in understanding how this drug acts on specific sites of the cellular membrane. (C) 2017 Elsevier B.V. All rights reserved.
Somente Metadadados
The interaction of mefloquine hydrochloride with cell membrane models at the air-water interface is modulated by the monolayer lipid composition
(Elsevier B.V., 2014-10-01) Goto, Thiago Eichi [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
The antiparasitic properties of antiparasitic drugs are believed to be associated with their interactions with the protozoan membrane, encouraging research on the identification of membrane sites capable of drug binding. in this study, we investigated the interaction of mefloquine hydrochloride, known to be effective against malaria, with cell membrane models represented by Langmuir monolayers of selected lipids. It is shown that even small amounts of the drug affect the surface pressure-area isotherms as well as surface vibrational spectra of some lipid monolayers, which points to a significant interaction. the effects on the latter depend on the electrical charge of the monolayer-forming molecules, with the drug activity being particularly distinctive for negatively charged lipids. Therefore, the lipid composition of the monolayer modulates the interaction with the lipophilic drug, which may have important implications in understanding how the drug acts on specific sites of the protozoan membrane. (C) 2014 Elsevier Inc. All rights reserved.
Somente Metadadados
Interaction of oligonucleotide-based amphiphilic block copolymers with cell membrane models
(Elsevier B.V., 2010-07-01) Caseli, L. [UNIFESP]; Pascholati, C. P.; Teixeira, F.; Nosov, S.; Vebert, C.; Mueeller, A. H. E.; Oliveira, O. N.; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Univ Basel; Univ Bayreuth
Oligonucleotides have unique molecular recognition properties, being involved in biological mechanisms such as cell-surface receptor recognition or gene silencing. for their use in human therapy for drug or gene delivery, the cell membrane remains a barrier, but this can be obviated by grafting a hydrophobic tail to the oligonucleotide. Here we demonstrate that two oligonucleotides, one consisting of 12 guanosine units (G(12)), and the other one consisting of five adenosine and seven guanosine (A(5)G(7)) units, when functionalized with poly(butadiene), namely PB-G(12) and PB-A(5)G(7), can be inserted into Langmuir monolayers of dipalmitoyl phosphatidyl choline (DPPC), which served as a cell membrane model. PB-G(12) and PB-A(5)G(7) were found to affect the DPPC monolayer even at high surface pressures. the effects from PB-G(12) were consistently stronger, particularly in reducing the elasticity of the DPPC monolayers, which may have important biological implications. Multilayers of DPPC and nucleotide-based copolymers could be adsorbed onto solid supports, in the form of Y-type LB films, in which the molecular-level interaction led to lower energies in the vibrational spectra of the nucleotide-based copolymers. This successful deposition of solid films opens the way for devices to be produced which exploit the molecular recognition properties of the nucleotides. (C) 2010 Elsevier Inc. All rights reserved.
Somente Metadadados
Interaction of violacein in models for cellular membranes: Regulation of the interaction by the lipid composition at the air-water interface
(Elsevier Science Bv, 2017) de Souza, Karine Damaceno [UNIFESP]; Perez, Katia Regina [UNIFESP]; Duran, Nelson; Justo, Giselle Zenker [UNIFESP]; Caseli, Luciano [UNIFESP]
Some biological properties of violacein are believed to be associated with their interactions with lipid surfaces, encouraging research on the identification of membrane sites capable of drug binding. In this study, we investigated the interaction of violacein with cell membrane models represented by Langmuir mono layers of selected lipids: one representing healthy cellular membranes: dipalmitoylphosphatidylcholine, DPPC, and the other one representing tumorigenic cellular membranes, dipalmitoylphosphatidylserine, DPPS. It is shown that even small amounts of the compound affect the surface pressure-area isotherms as well as the surface vibrational spectra of the lipid monolayers, which points to a significant interaction. Such effects depend on the electrical charge of the monolayer-forming molecules, with the drug activity being particularly distinctive for negatively charged lipids in relation to zwitterionic lipids. Morphological analysis also suggests that violacein at the air-water interface is homogenized when incorporated in both lipids. Although the interaction of violacein with the lipids affects viscoelastic and structural properties of the Langmuir monolayer, it is not present permeability through lipid bilayers, as investigated using liposomes. These results therefore may have important implications in understanding how violacein acts on specific sites of the cellular membrane, and evidence the fact that the lipid composition of the monolayer modulates the interaction with the lipophilic drug. (C) 2017 Published by Elsevier B.V.
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Langmuir and Langmuir-Blodgett films of lipids and penicillinase: Studies on adsorption and enzymatic activity
(Elsevier B.V., 2015-02-01) Scholl, Fabio Antonio [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
Bioelectronic devices, such as biosensors, can be constructed with enzymes immobilized in ultrathin solid films, for which preserving the enzymatic catalytic activity is fundamental for optimal performance. in this sense, nanostructured films in which molecular architectures can be controlled are of interest. in this present work, the adsorption of the enzyme penicillinase onto Langmuir monolayers of the phospholipid dimyristoylphosphatidic acid was investigated and characterized with surface pressure-area isotherms and polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS). the incorporation of the enzyme in the lipid monolayer not only caused the film to expand, but also could be identified through amide bands in the PM-IRRAS spectra, with the C-N and C=O dipole moments being identified, lying parallel to monolayer plane. Structuring of the enzyme into a-helices was identified in the mixed enzyme-phospholipid monolayer and preserved when transferred to solid as a Langmuir-Blodgett (LB) film. the enzyme-lipid LB films were then characterized with PM-IRRAS, atomic force microscopy and fluorescence spectroscopy. Measurements of the catalytic activity showed that the enzyme accommodated in the LB films preserved 76% of the enzyme activity in relation to the homogeneous medium. the method presented here not only allows for enhanced catalytic activity toward penicillin, but also can be useful to explain why certain film architectures exhibit better enzyme activity. (C) 2014 Elsevier B.V. All rights reserved.
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Properties of lipophilic nucleoside monolayers at the air-water interface
(Elsevier B.V., 2010-06-01) Montanha, E. A.; Pavinatto, F. J.; Caseli, L. [UNIFESP]; Kaczmarek, O.; Liebscher, J.; Huster, D.; Oliveira, O. N.; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Humboldt Univ; Univ Leipzig
The capability of self-assembly and molecular recognition of biomolecules is essential for many nanotechnological applications, as in the use of alkyl-modified nucleosides and oligonucleotides to increase the cellular uptake of DNA and RNA. in this study, we show that a lipophilic nucleoside, which is an isomer mixture of 2'-palmitoyluridin und 3'-palmitoyluridin, forms Langmuir monolayers and Langmuir-Blodgett films as a typical amphiphile, though with a smaller elasticity. the nucleoside may be incorporated into dipalmitoyl phosphatidyl choline (DPPC) monolayers that serve as a simplified cell membrane model. the molecular-level interactions between the nucleoside and DPPC led to a remarkable condensation of the mixed monolayer, which affected both surface pressure and surface potential isotherms. the morphology of the mixed monolayers was dominated by the small domains of the nucleoside. the mixed monolayers could be deposited onto solid substrates as a one-layer Langmuir Blodgett film that displayed UV-vis absorption spectra typical of aggregated nucleosides owing to the interaction between the nucleoside and DPPC. the formation of solid films with DNA building blocks in the polar heads may open the way for devices and sensors be produced to exploit their molecular recognition properties. (C) 2010 Elsevier B.V. All rights reserved.

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