Influência dos ácidos graxos do tipo ômega-3 ou ômega-6 e o nanomaterial de carbono fulereno (C60) no estado antioxidante em suspensões celulares de cérebro de Cyprinus carpio (Pisces, Cyprinidae)

Os nanomateriais de carbono como o fulereno (C60) apresenta comportamentos bioquímicos distintos, podendo atuar como antioxidante ou pró-oxidante em diferentes sistemas biológicos. Outra evidência ao C60 refere-se a sua característica lipofilica, na qual oferece ação mais direta a diferentes tipos de membranas celulares. Do mesmo modo ácidos graxos poliinsaturados (AGPs) como o ômega-3 (DHA) e o ômega-6 (LA) são importantes para funções celulares da membrana, sendo considerados antioxidantes clássicos. Dessa forma este estudo avaliou em suspensões celulares de cérebro da carpa (Cyprinus carpio, Cyprinidae), o efeito de C60 após um pré-tratamento com DHA ou LA. Para tal avaliação os ensaios consistiram em um pré-tratamento com AGPs (48h) e após exposição a C60 (2h). Como resultados observamos que a viabilidade celular e a capacidade antioxidante total não apresentaram diferença (p> 0.05) entre todos os grupos. Em relação a valores de espécies ativas de oxigênio e dano lipídico foi observado redução nos seus valores nos grupos expostos ao C60 pré – tratados com AGPs (p<0.05). Em termos de cisteína, ocorre uma redução da sua concentração em todos os grupos expostos ao C60. Porém para glutationa a exposição ao C60 provoca um aumento de sua concentração nos grupo controle (sem AGPs) e no grupo pré – tratado com DHA. Dessa forma consideramos que o pré – tratamento com AGPs é benéfico às células, uma vez que um aumento nos níveis de glutationa e uma diminuição na concentração de espécies ativas de oxigênio e peroxidação lipídica foram observados nos grupos expostos ao C60. Sendo assim um bom estado nutritivo em termos da concentração de AGPs foi considerado benéfico na exposição ao fulereno.

Chemical and physical effects of ultrasound: sonoluminescence and materials

When a liquid is irradiated with ultrasound, acoustic cavitation (the formation, growth, and implosive collapse of bubbles in liquids irradiated with ultrasound) generally occurs. This is the phenomenon responsible for the driving of chemical reactions (sonochemistry) and the emission of light (sonoluminescence). The implosive collapse of bubbles in liquids results in an enormous concentration of sound energy into compressional heating of the bubble contents. Therefore, extreme chemical and physical conditions are generated during cavitation. The study of multibubble sonoluminescence (MBSL) and single-bubble sonoluminescence (SBSL) in exotic liquids such as sulfuric acid (H2SO4) and phosphoric acid (H3PO4) leads to useful information regarding the intracavity conditions during bubble collapse. Distinct sonoluminescing bubble populations were observed from the intense orange and blue-white emissions by doping H2SO4 and H3PO4 with sodium salts, which provides the first experimental evidence for the injected droplet model over the heated-shell model for cavitation. Effective emission temperatures measured based on excited OH• and PO• emission indicate that there is a temperature inhomogeneity during MBSL in 85% H3PO4. The formation of a temperature inhomogeneity is due to the existence of different cavitating bubble populations: asymmetric collapsing bubbles contain liquid droplets and spherical collapsing bubbles do not contain liquid droplets. Strong molecular emission from SBSL in 65% H3PO4 have been obtained and used as a spectroscopic probe to determine the cavitation temperatures. It is found that the intracavity temperatures are dependent on the applied acoustic pressures and the thermal conductivities of the dissolved noble gases. The chemical and physical effects of ultrasound can be used for materials synthesis. Highly reactive species, including HO2•, H•, and OH• (or R• after additives react with OH•), are formed during aqueous sonolysis as a consequence of the chemical effects of ultrasound. Reductive species can be applied to synthesis of water-soluble fluorescent silver nanoclusters in the presence of a suitable stabilizer or capping agent. The optical and fluorescent properties of the Ag nanoclusters can be easily controlled by the synthetic conditions such as the sonication time, the stoichiometry of the carboxylate groups to Ag+, and the polymer molecular weight. The chemical and physical effects of ultrasound can be combined to prepare polymer functionalized graphenes from graphites and a reactive solvent, styrene. The physical effects of ultrasound are used to exfoliate graphites to graphenes while the chemical effects of ultrasound are used to induce the polymerization of styrene which can then functionalize graphene sheets via radical coupling. The prepared polymer functionalized graphenes are highly stable in common organic solvents like THF, CHCl3, and DMF. Ultrasonic spray pyrolysis (USP) is used to prepare porous carbon spheres using energetic alkali propiolates as the carbon precursors. In this synthesis, metal salts are generated in situ, introducing porous structures into the carbon spheres. When different alkali salts or their mixtures are used as the precursor, carbon spheres with different morphologies and structures are obtained. The different precursor decomposition pathways are responsible for the observed structural difference. Such prepared carbon materials have high surface area and are thermally stable, making them potentially useful for catalytic supports, adsorbents, or for other applications by integrating other functional materials into their pores.

Evaluation of the cytotoxic and genotoxic effects of benchmark multi-walled carbon nanotubes in relation to their physicochemical properties

To contribute with scientific evidence to the grouping strategy for the safety assessment of multi-walled carbon nanotubes (MWCNTs), this work describes the investigation of the cytotoxic and genotoxic effects of four benchmark MWCNTs in relation to their physicochemical characteristics, using two types of human respiratory cells. The cytotoxic effects were analysed using the clonogenic assay and replication index determination. A 48h-exposure of cells revealed that NM-401 was the only cytotoxic MWCNT in both cell lines, but after 8-days exposure, the clonogenic assay in A549 cells showed cytotoxic effects for all the tested MWCNTs. Correlation analysis suggested an association between the MWCNTs size in cell culture medium and cytotoxicity. No induction of DNA damage was observed after any MWCNTs in any cell line by the comet assay, while the micronucleus assay revealed that both NM-401 and NM-402 were genotoxic in A549 cells. NM-401 and NM-402 are the two longest MWCNTs analyzed in this work, suggesting that length may be determinant for genotoxicity. No induction of micronuclei was observed in Beas-2B cell line and the different effect in both cell lines is explained in view of the size-distribution of MWCNTs in the cell culture medium, rather than cell's specificities.

Niosomes as Nanoparticular Drug Carriers: Fundamentals and Recent Applications

Drug delivery systems are defined as formulations aiming for transportation of a drug to the desired area of action within the body. The basic component of drug delivery systems is an appropriate carrier that protects the drug from rapid degradation or clearance and thereby enhances drug concentration in target tissues. Based on their biodegradable, biocompatible, and nonimmunogenic structure, niosomes are promising drug carriers that are formed by self-association of nonionic surfactants and cholesterol in an aqueous phase. In recent years, numerous research articles have been published in scientific journals reporting the potential of niosomes to serve as a carrier for the delivery of different types of drugs. The present review describes preparation methods, characterization techniques, and recent studies on niosomal drug delivery systems and also gives up to date information regarding recent applications of niosomes in drug delivery.

Investigations of the Toxic Effect of Silver Nanoparticles on Mammalian Cell Lines

Silver nanoparticles are widely used for many applications. In this study silver nanoparticles have been tested for their toxic effect on fibroblasts (NIH-3T3), on a human lung adenocarcinoma epithelial cell line (A-549), on PC-12-cells, a rat adrenal pheochromocytoma cell line, and on HEP-G2-cells, a human hepatocellular carcinoma cell line. The viability of the cells cultivated with different concentrations of silver was determined by the MTT assay, a photometric method to determine cell metabolism. Dose-response curves were extrapolated and IC50, total lethal concentration (TLC), and no observable adverse effect concentration (NOAEC) values were calculated for each cell line. As another approach, ECIS (electric-cell-substrate-impedance-sensing) an automated method to monitor cellular behavior in real-time was applied to observe cells cultivated with silver nanoparticles. To identify the type of cell death the membrane integrity was analyzed by measurements of the lactate dehydrogenase releases and by determination of the caspase 3/7 activity. To ensure that the cytotoxic effect of silver nanoparticles is not traced back to the presence of Ag+ ions in the suspension, an Ag+ salt (AgNO3) has been examined at the same concentration of Ag+ present in the silver nanoparticle suspension that is assuming that the Ag particles are completely available as Ag+ ions.

Nanotubos de carbono de parede simples funcionalizados com polietilenoglicol: avaliação de parâmetros in vivo e in vitro

Os nanomateriais apresentam uma escala na qual ao menos uma das dimensões varia entre 1 e 100 nm e possuem propriedades químicas, físicas ou biológicas dependentes da nanoestrutura e que lhes confere características funcionais de interesse para fins comerciais ou aplicações na área médica. Dentre os nanomateriais mais estudados e utilizados, destacam-se os de carbono, que incluem os fulerenos e os nanotubos de carbono (NT). Uma potencial utilização dos nanomateriais de carbono é na área biomédica, já que estes podem interagir com os sistemas biológicos em nível molecular e supramolecular com alto grau de especificidade. Em contrapartida, é importante considerar que os nanotubos de carbono podem exercer efeitos tóxicos, tendo como possível mecanismo o estresse oxidativo. Sendo assim, o objetivo desse trabalho foi investigar a ação dos nanotubos de carbono de parede única funcionalizados com polietilenoglicol (SWNT-PEG) em Danio rerio “zebrafish” (Teleostei, Cyprinidae). Avaliaram-se parâmetros bioquímicos, histológicos, comportamentais e de biodistribuição para entender como esse material se comporta in vitro e in vivo. Foi observado que o tipo de funcionalização é determinante para a ação desse material em meio biológico. No experimento in vitro o SWNT-PEG não mostrou efeito pró-oxidante nas avaliações de peroxidação lipídica, capacidade antioxidante total, conteúdo de GSH e atividade de GCL. Na exposição intraperitoneal em zebrafish constatou-se a agregação e geração de processo inflamatório, o que sugere que a cadeia de PEG utilizada para a funcionalização dos NT possui um tamanho inadequado e/ou uma funcionalização ineficiente para manter a estabilidade do material em meio biológico e evitar uma resposta inflamatória por parte do organismo exposto. Possivelmente devido a esta característica do nanomaterial, nas análises de biodistribuição, através de espectroscopia Raman, não se observou distribuição de SWNT-PEG no sistema nervoso central de zebrafish. No entanto, através da análise histológica foi observado processo inflamatório no tecido nervoso central, bem como alterações comportamentais avaliadas na tarefa de campo aberto.

Membrana de alumina anódica: comportamento da microestrutura e estudo das propriedades ópticas após tratamento térmico

Thin commercial aluminum electrolytic and passed through reactions was obtained with anodic alumina membranes nanopores. These materials have applications in areas recognized electronic, biomedical, chemical and biological weapons, especially in obtaining nanostructures using these membranes as a substrate or template for processing nanowires, nanodots and nanofibers for applications noble. Previous studies showed that the membranes that have undergone heat treatment temperature to 1300° C underwent changes in morphology, crystal structure and optical properties. This aim, this thesis, a study of the heat treatment of porous anodic alumina membranes, in order to obtain and to characterize the behavior changes structures during the crystallization process of the membranes, at temperatures ranging between 300 and 1700° C. It was therefore necessary to mount a system formed by a tubular furnace resistive alumina tube and controlled environment, applying flux with special blend of Ag-87% and 13% N2, in which argon had the role of carrying out the oxygen nitrogen system and induce the closing of the pores during the densification of the membrane. The duration of heat treatment ranged from 60 to 15 minutes, at temperatures from 300 to 1700° C respectively. With the heat treatment occurred: a drastic reduction of porosity, grain growth and increased translucency of the membrane. For the characterization of the membranes were analyzed properties: Physical - thermogravimetric, X-ray diffraction, BET surface area; morphological - SEM, EDS through compositional and, optical absorbance, and transmittance in the UV-VIS, and FTIR. The results using the SEM showed that crystallization has occurred, densification and significant changes in membrane structure, as well as obtaining microtube, the BET analysis showed a decrease in specific surface area of the membranes has to 44.381 m2.g-1 to less than 1.8 m2.g-1 and in the analysis of transmittance and absorbance was found a value of 16.5% in the range of 800 nm, characteristic of the near infrared and FTIR have confirmed the molecular groups of the material. Thus, one can say that the membranes were mixed characteristics and properties which qualify for use in gas filtration system, as well as applications in the range of optical wavelength of the infra-red, and as a substrate of nanomaterials. This requires the continuation and deepening of additional study

Multibiomarker assessment of cadmium-based quantum dots effects in the marine mussel Mytilus galloprovincialis

Tese de Doutoramento, Ciências do Mar, da Terra e do Ambiente, Ramo: Ciências e Tecnologias do Ambiente, Especialização em Ecotoxicologia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016

Design, Fabrication, and Mechanical Property Analysis of 3D Nanoarchitected Materials

Recent developments in micro- and nanoscale 3D fabrication techniques have enabled the creation of materials with a controllable nanoarchitecture that can have structural features spanning 5 orders of magnitude from tens of nanometers to millimeters. These fabrication methods in conjunction with nanomaterial processing techniques permit a nearly unbounded design space through which new combinations of nanomaterials and architecture can be realized. In the course of this work, we designed, fabricated, and mechanically analyzed a wide range of nanoarchitected materials in the form of nanolattices made from polymer, composite, and hollow ceramic beams. Using a combination of two-photon lithography and atomic layer deposition, we fabricated samples with periodic and hierarchical architectures spanning densities over 4 orders of magnitude from ρ=0.3-300kg/m³ and with features as small as 5nm. Uniaxial compression and cyclic loading tests performed on different nanolattice topologies revealed a range of novel mechanical properties: the constituent nanoceramics used here have size-enhanced strengths that approach the theoretical limit of materials strength; hollow aluminum oxide (Al₂O₃) nanolattices exhibited ductile-like deformation and recovered nearly completely after compression to 50% strain when their wall thicknesses were reduced below 20nm due to the activation of shell buckling; hierarchical nanolattices exhibited enhanced recoverability and a near linear scaling of strength and stiffness with relative density, with E∝ρ^1.04 and σy∝ρ^1.17 for hollow Al₂O₃ samples; periodic rigid and non-rigid nanolattice topologies were tested and showed a nearly uniform scaling of strength and stiffness with relative density, marking a significant deviation from traditional theories on “bending” and “stretching” dominated cellular solids; and the mechanical behavior across all topologies was highly tunable and was observed to strongly correlate with the slenderness λ and the wall thickness-to-radius ratio t/a of the beams. These results demonstrate the potential of nanoarchitected materials to create new highly tunable mechanical metamaterials with previously unattainable properties.

Synthesis of porous graphene/TiO2 by use of recycled graphite

Graphene-based nanomaterials are a kind of new technological materials with high interest for physicists, chemists and materials scientists. Graphene is a two-dimensional (2-D) sheet of carbon atoms in a hexagonal configuration with atoms bonded by sp2 bonds. These bonds and this electron configuration provides the extraordinary properties of graphene, such as very large surface area, a tunable band gap, high mechanical strength and high elasticity and thermal conductivity [1]. Graphene has also been investigated for preparation of composites with various semiconductors like TiO2, ZnO, CdS aiming at enhanced photocatalytic activity for their use for photochemical reaction as water splitting or CO2 to methanol conversion [2-3]. In this communication, the synthesis of porous graphene@TiO2 obtained from a powder graphite recycled, supplied by ECOPIBA, is presented. This graphite was exfoliated, using a nonionic surfactant (Triton X-100) and sonication. Titanium(IV) isopropoxide was used as TiO2 source. After removing the surfactant with a solution HCl/n-propanol, a porous solid is obtained with a specific area of 358 m2g-1. The solid was characterized by XRD, FTIR, XPS, EDX and TEM. Figure 1 shows the graphene 2D layer bonded with nanoparticles of TiO2. When a water suspension of this material is exposed with UV-vis radiation, water splitting reaction is carried out and H2/O2 bubbles are observed (Figure 2)

Pirólise de borras oleosas de petroleo utilizando nanomateriais

The oily sludge is a complex mix of hydrocarbons, organic impurities, inorganic and water. One of the major problems currently found in petroleum industry is management (packaging, storage, transport and fate) of waste. The nanomaterials (catalysts) mesoporous and microporous are considered promising for refining and adsorbents process for environment protection. The aim of this work was to study the oily sludge from primary processing (raw and treated) and vacuum residue, with application of thermal analyses technique (pyrolysis), thermal and catalytic pyrolysis with nanomaterials, aiming at production petroleum derived. The sludge and vacuum residue were analyzed using a soxhlet extraction system, elemental analysis, thin layer chromatography, thermogravimetry and pyrolysis coupled in gas chromatography/mass spectrometry (Py GC MS). The catalysts AlMCM-41, AlSBA-15.1 e AlSBA-15.2 were synthesized with molar ratio silicon aluminum of 50 (Si/Al = 50), using tetraethylorthosilicante as source of silicon and pseudobuhemita (AlOOH) as source of aluminum. The analyzes of the catalysts indicate that materials showed hexagonal structure and surface area (783,6 m2/g for AlMCM-41, 600 m2/g for AlSBA-15.1, 377 m2/g for AlSBA-15.2). The extracted oily sludge showed a range 65 to 95% for organic components (oil), 5 to 35% for inorganic components (salts and oxides) and compositions different of derivatives. The AlSBA-15 catalysts showed better performance in analyzes for production petroleum derived, 20% increase in production of kerosene and light gas oil. The energy potential of sludge was high and it can be used as fuel in other cargo processed in refinery

Avaliação ecotoxicológica de fármacos psicotrópicos e suas possíveis interações com nanomateriais usando embriões de peixe-zebra

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Programa de Pós-Graduação em Biologia Animal, 2016.