Abstract Cationic surfactant cetyltrimethyl ammonium brombide (CTAB) was used as template to synthesize aluminosilicate MCM-41 (plane group P6m, hexagonal array of uniform mesopores derived from crystalline colloidal array (CCA)) molecular sieve and lamellar phases in colloidal solution with negatively charged silicate and aluminate species at pH=10. In the first part, sodium aluminate (up to 0.25 molar ratio) and sodium silicate were the precursor of Al and Si, respectively; in the second part, kaolinite (Al4[Si4O10](OH)8) was used instead. The hydrothermally reacted (100oC in a Teflon sealed container) materials subject to room temperature drying, calcination (540oC) or ethanol rinsing were studied by X-ray diffraction (XRD), optical microscopy under plane polarized light or transmission electron microscopy (TEM) with emphasis on the microstructures and formation mechanism of mesophases, MCM-41, and gibbsite (Al(OH)3) at a relatively low CTAB/water ratio and the effect of Al/Si ratio on micelle interspacing in terms of micelle size and aluminosilicate wall thickness. In the first part, both calcination and ethanol rinsing were shown to remove the template successfully. The resultant MCM-41 particulates were more or less coalesced and the elongated ones tended to be folded. The hexagonal MCM-41 has a tube interspacing 4.5-5.4 nm and tube wall thickness 1.9-3.7 nm, both generally increasing with the increase of sodium aluminate/sodium silicate ratio up to 0.1 molar. ratio. The tube diameter also increased slightly presumably because of competitive electrostatic coordination of the hydrophilic head of CTAB with the negatively charged aluminate (AlO2-) vs. silicate (SiO4-4) species stable at pH=10. The MCM-41 particulates have well-developed {100} faces, the close-packed plane of 2-D hexagonal structure, and rigid amorphous tube walls, suggesting interface-controlled assembly of rod-like CTAB micelles with their polar head already incorporated with aluminosilicate. Tubules-within-a-tubule were corrugated and folded when extended beyond a certain persistence length, typically 1 mm. Spherical particles with disordered mesopores (typically ca. 4 nm in mesh size) due to entanglement of micelles under semi-dilute condition were also formed. In the second part, the CTAB-saturated solution at pH=10 was separated from mud-like kaolinite to form translucent hydrous gel. Upon drying on a glass slide at room temperature, the gel became whitish because of the following crystallization events. First, whitish gibbsite nucleated preferentially at gel/air and gel/glass interface to form spherulites. The spiral and lateral growth of plate-like gibbsite crystal with {100} and {110} growth front was rapid enough to entrap solution droplets. Subsequently, dendritic lamellar (basal spacing ca. 2.6 nm according to XRD and TEM observations) mesophase exhibiting length fast and clino-extinction with extinction angle 42o was formed via 2-D growth near the edge of the drying gel. This lamellar phase was incorporated with aluminate according to TEM-EDX analysis. Finally, explosive nucleation and dendritic growth of isotropic phase concluded the crystallization. This final event involved surface nucleation as best exhibited at the droplets trapped in gibbsite host. Upon calcination to remove the surfactant, the aluminosilicate MCM-41 retained while aluminate-incorporated lamellar mesophase disappeared as indicated by XRD. In an additional experiment to understand the crystallization behavior of CTAB in drying water, we found that the plate-like and then dendritic monoclinic lamellar phase (space group P21/c) with optical extinction angle of 37o was formed as the growth dimensionality decreased toward the edge of the gel. This nucleation and growth process is analogous to the CTAB/water system with negatively charged silicate and aluminate species derived from kaolinite at pH=10.

No description available.

Monodisperse Pd nanocubes of 20 nm rib length and Pd nanospheres of 3 nm diameter deposited on corundum were used as efficient tool to reveal structure sensitivity of three-phase hydrogenations of unsaturated alcohols. For an olefin alcohol hydrogenation in the kinetic regime, surface (100) atoms of the cubes displayed lower activity than other surface atoms of the spheres. Apparent activation energies of 23 kJ/mol for the cubes and 17 kJ/mol for the spheres confirmed the reaction structure sensitivity. In an acetylenic alcohol hydrogenation, the cubes showed higher selectivity to an olefinic product than the spheres. Apparent activation energy was found as 38 kJ/mol for the cubes and 24 kJ/mol for the spheres. The apparent structure sensitivity in this case was attributed to liquid-solid mass transfer limitations governing the sphere-catalyzed reactions. The study shows the applicability and limitations of the use of nanoparticles for structure sensitivity studies in catalysis. / Chemical Engineering

Molecular dynamics (MD) is a computer simulation of physical movements of atoms and molecules. MD has now been widely used in materials, biochemical and pharmaceutical research. In recent years, zirconium phosphate (ZrP) compounds developed a new type of multi-function mediated porous materials, which the crystalline £\-zirconium phosphate (£\-ZrP) is a cationic layered compounds, with a neat layer structure and easy to design. Cetyl trimethyl ammonium bromide (CTAB) is a cationic surfactant, it¡¦s one kind of ammonium salt of a long carbon chain as hydrophobic groups. Ion exchange can occur with other exchangeable cations. In this study, we first use CTAB inserted into £\-ZrP interlayer to prepare £\-ZrP-CTAB material. Second, we add phenol solution in the system, and use molecular dynamics simulations to observe the solution¡¦s penetration and adsorption. The result shows that pure water can permeate through £\-ZrP CTAB membrane, and pure phenol will be adsorbed by the £\-ZrP-CTAB membrane. If we add phenol solution, the water molecules can pass through the £\-ZrP-CTAB membrane but phenol molecule can¡¦t. It can achieve the effect of separation of the mixed solution. Last we simulate phenolate solution system. The result shows that the number of phenolate molecule enter the membrane is less than phenol molecule in phenol solution. This result is also consistent with the experiments mentioned in the literature.

No description available.

O objetivo deste trabalho é estudar o nível de organização dos cristalitos de surfactantes aniônico, catiônico e zwiteriônico com o aumento na densidade destas moléculas sobre um cristal de germânio. As análises foram realizadas por espectroscopia de infravermelho com transformada de Fourier acoplada à técnica de reflexão total atenuada (FTIR-ATR). Este estudo apresenta importantes aspectos na organização do dodecilsulfato de sódio (SDS), do N-hexadecil-N,N-dimetil-3-amônio-1-propanosulfato (HPS), do brometo de hexadeciltrimetilamônio (CTAB) e do brometo de dodeciltrimetilamônio (DTAB). No SDS é observado um deslocamento de 1.7 cm-1 para valores de maior frequência na banda de estiramento assimétrico do CH2, vass (CH2), enquanto que é observado um deslocamento de 0.9 cm-1 na banda de estiramento simétrico, vsim (CH2). Este deslocamento para valores de maior frequência nas bandas de estiramento está associado com um aumento na desorganização da cadeia alifática com o aumento na densidade de moléculas sobre o elemento de ATR. A banda de deformação angular do CH2, δ(CH2), apresenta um valor em 1468 cm-1 que é também um indicativo de desorganização. No CTAB não é observado variações acentuadas nos valores das frequências vibracionais. Na banda vass (CH2) do DTAB é observado um deslocamento de 4.5 cm-1 para valores de menor frequência. Embora seja observado valores próximos de 2920 cm-1 para a banda vass (CH2), que é um indicativo do estado líquido de surfactantes, o que é observado nesse estudo são cristalitos de DTAB. O deslocamento da banda vsim (CH2) do DTAB é da ordem de 2 cm-1. Estas mudanças nas bandas vass (CH2) e vsim (CH2) são um indicativo da diminuição nas conformações gauche e um aumento nas conformações trans ao longo da cadeia alifática. O valor da freqüência em torno de 1472 cm-1 para a banda δ(CH2) é também um indicativo de uma maior organização na cadeia de CH2 do DTAB. Para o HPS é observado um deslocamento de 2.6 e 2.7 cm-1 para valores de maior frequência nas bandas vass (CH2) e vsim (CH2), respectivamente. A banda δ(CH2) do HPS apresenta um deslocamento de 4 cm-1 para valores de maior frequência. A variação nas bandas vass (CH2), vsim (CH2), e δ(CH2) ressalta o aumento na desorganização da cadeia alifática com o aumento na densidade de moléculas de HPS sobre o germânio. / The objective of this work is study the order level of anionic, cationic and zwitterionic surfactants with the increase of their density packing on the surface of a germanium element. The analyses were performed by a Fourier transform infrared-attenuated total reflection spectroscopy. This study shows important insights on the conformational order of sodium dodecyl sulfate (SDS), N-hexadecyl-N-N -dimethyl-3-ammonio-1-propane-sulfonate (HPS), hexadecyl-trimethylammonium bromide (CTAB) and dodecyl trimethylammonium bromide (DTAB). It is observed a shift of 1.7 and 0.9 cm-1 to higher frequency values of the CH2 asymmetric (vass (CH2)) and symmetric (vsim(CH2)) stretching bands for the SDS molecules, respectively. The latter shift to higher frequency values is associated with the disorder of the aliphatic chain due to the increase of density packing of SDS molecules on the germanium element. The CH2 scissoring band [δ (CH2)] shows a value in 1468 cm-1, which is also an indicative of conformational disorder. It is not observed any accentuated change on the vibrational frequency values of the CTAB molecules. The vass (CH2) band of the DTAB molecules is shifted 4.5 cm-1 to lower frequency values. Although it is observed values near 2920 cm-1 for the vass(CH2) band, indicating a surfactant liquid phase, it is shown in this study that there are indeed DTAB crystallites. The shift of DTAB vsim(CH2) band is around 2 cm-1. These changes in vass(CH2) and vsim(CH2) band are an indicative of a decrease in gauche conformations and an increase in all-trans conformations over the aliphatic chain. The frequency value around 1472 cm-1 for the δ(CH2) band is also an indicative of the order in CH2 chain of DTAB. It is observed a shift of 2.6 and 2.7 cm-1 to higher frequency values of vass (CH2) and vsim(CH2) bands of the HPS molecule, respectively. The δ(CH2) band of the HPS molecule presents a shift of 4 cm-1 to higher frequency values. These variations in vass (CH2), vsim(CH2), and δ(CH2) bands stand out the disorder of the aliphatic chain due to the increase of the density packing for the HPS molecules on the germanium surface.

Ultimamente têm-se buscado tratamentos menos invasivos para o câncer, como os que utilizam campos magnéticos ou luz, e dentre esses últimos, aqueles que fazem uso de materiais, geralmente metálicos, com propriedade de ressonância plasmônica de superfície. O tratamento hipertérmico encaixa-se neste perfil e já apresenta resultados promissores com nanoshells de sílica recoberta por ouro e com nanobarras de ouro maciço, apesar de pouco se saber sobre o mecanismo de ação e sobre como as vias de morte celular são ativadas em tal tratamento. A síntese das nanobarras envolve o uso do composto brometo de cetiltrimetilamônio (CTAB), o qual permanece aderido à superfície das mesmas, porém é caracterizado por apresentar extrema citotoxicidade, fato que incita a modificação do recobrimento das nanopartículas por um biopolímero mais compatível. Estudos recentes indicam que o CTAB aderido à membrana não apresenta citotoxicidade considerável, porém há poucos dados que confirmem tal hipótese na literatura. Este trabalho se propôs a investigar a via de ativação da morte celular, bem como confirmar a hipótese de que as partículas recobertas por CTAB podem ser utilizadas para tratamento antitumoral fototérmico in vivo de forma segura. Para isso, nanobarras de ouro foram sintetizadas pelo método de seeding, sendo parte delas centrifugadas e lavadas com água deionizada por três vezes para retirar o CTAB e a outra parte deixada com CTAB no meio. As partículas foram testadas in vitro pelo teste de citotoxicidade pelo [brometo de 3-(4, 5-dimetiltiazol-2-yl)-2,5-difeniltetrazólio] (MTT) nas linhagens celulares HTC, HepG2, HT-29 e 786-O, e também foram testadas quanto à sua viabilidade com o tempo decorrido desde sua síntese. Após confirmar que as nanobarras centrifugadas e lavadas podem ser utilizadas no tratamento hipertérmico sem riscos à saúde e após verificar que as seeds e as nanobarras devem ser utilizadas até 48 horas depois de sua síntese, as nanopartículas foram utilizadas para tratamento de tumor de Ehrlich (induzido no dorso de camundongos). Para isso, foram organizados quatro grupos experimentais: L (camundongos não receberam nanopartículas, irradiados com laser em 808 nm), N (camundongos receberam nanopartículas, não irradiados com laser), H (camundongos receberam nanopartículas e irradiados com laser em 808 nm) e Controles (camundongos não receberam nanopartículas nem irradiação por laser). O material tumoral foi coletado após a irradiação e submetido à análise histológica, ao teste de quimiluminescência para avaliar a lipoperoxidação de membrana e ao teste de TRAP (do inglês, Total Radical-Trapping Antioxidant Parameter) para avaliar a capacidade antioxidante total. Após a irradiação com 2 W/\'CM POT.2\' ou 720 mW/\'CM POT.2\' de intensidade, houve evidente redução do volume tumoral nos animais do grupo H tratados com laser na maior potência utilizada, com um aumento de 47ºC (temperatura final de 79ºC) observado localmente. Nos animais do grupo H tratados com laser na menor potência utilizada, os danos foram menores. Os animais dos grupos L e H apresentaram semelhante lipoperoxidação, maior que no grupo N (estatisticamente significante somente nos animais tratados com laser em intensidade de 2 W/\'CM POT.2\'), e a capacidade antioxidante dos tumores dos animais do grupo H foi elevada no protocolo com laser em 2 W/\'CM POT.2\'. Os resultados indicam que a necrose é a via de morte ativada prioritariamente neste caso e que o tratamento com as nanobarras se mostrou eficaz. / Less invasive cancer treatments, likewise those based on magnetic fields or light, are in the most common aims of researchers nowadays. Regarding light based treatments, those in which metallic, plasmonic materials are highlighted in research field. Hiperthermic treatment fits this profile, once it already presents promising results with gold-coated silica nanoshells and with gold nanorods, although little is known about its action mechanism or about how cell death pathways are activated. The compound cetyltrimethylammonium bromide (CTAB) is necessary for the nanorods synthesis, but is known to be extremely cytotoxic, fact that instigates the modification of nanorods surface coating by a compatible biopolymer. Recent studies indicate that surface-adhered CTAB does not present significant cytotoxicity, but there are few evidences to confirm this hypothesis in the literature. This study aims to investigate the cell death pathway that can be activated, as well as to confirm the possibility of safe CTAB-coated nanoparticles use in antitumor in vivo treatments. For that, gold nanorods were synthesized by the seeding method and part of them were centrifuged and washed with deionized water to eliminate CTAB of the solution and the rest remained with CTAB. The particles were tested in vitro by [3-(4, 5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) cytotoxicity test, in HTC, HepG2, HT-29 and 786-O cancer cell lines, and investigated regarding their viability through time after their synthesis. After confirming that centrifuged and washed nanorods can be used in hiperthermic therapy without health risks, and after find out that seeds and nanorods must be used within 48 hours after their synthesis, those nanoparticles were used for in vivo hyperthermic Ehrlich tumor (induced on the back of mices) treatment. Four experimental groups were organized: L (mice did not receive nanoparticles, treated with laser at 808 nm), N (mice received nanoparticles, not treated with laser), and H (mice received nanoparticles and treated with laser at 808 nm) and Controls (mice did not receive nanoparticles and were not treated with laser). A tumor biopsy was taken after laser irradiation and was subjected to histological analysis, by a chemiluminescence assay to evaluate membrane lipoperoxidation, and by Total Radical-Trapping Antioxidant Parameter (TRAP) assay as well, to evaluate total antioxidant capacity. After irradiation with laser (intensities of 2 W/\'CM POT.2\' or 720 mW/\'CM POT.2\'), there was an evident tumor volume reduction in animals of H group treated with higher power laser, with a 47ºC rise in temperature (final temperature was 79ºC) observed locally. The damages in the tumors irradiated with lower power laser were less intense. The animals of L and H groups showed similar membrane lipoperoxidation, which was more intense than in N animals (statistically significant just in the animals treated with higher intensity of radiation). The antioxidant capacity of H animals tumor was elevated also in the animals treated with higher energy. Our results indicate that necrosis is the main activated cell death pathway in this case, and that nanorods treatment is worth it.

O objetivo deste trabalho é estudar o nível de organização dos cristalitos de surfactantes aniônico, catiônico e zwiteriônico com o aumento na densidade destas moléculas sobre um cristal de germânio. As análises foram realizadas por espectroscopia de infravermelho com transformada de Fourier acoplada à técnica de reflexão total atenuada (FTIR-ATR). Este estudo apresenta importantes aspectos na organização do dodecilsulfato de sódio (SDS), do N-hexadecil-N,N-dimetil-3-amônio-1-propanosulfato (HPS), do brometo de hexadeciltrimetilamônio (CTAB) e do brometo de dodeciltrimetilamônio (DTAB). No SDS é observado um deslocamento de 1.7 cm-1 para valores de maior frequência na banda de estiramento assimétrico do CH2, vass (CH2), enquanto que é observado um deslocamento de 0.9 cm-1 na banda de estiramento simétrico, vsim (CH2). Este deslocamento para valores de maior frequência nas bandas de estiramento está associado com um aumento na desorganização da cadeia alifática com o aumento na densidade de moléculas sobre o elemento de ATR. A banda de deformação angular do CH2, δ(CH2), apresenta um valor em 1468 cm-1 que é também um indicativo de desorganização. No CTAB não é observado variações acentuadas nos valores das frequências vibracionais. Na banda vass (CH2) do DTAB é observado um deslocamento de 4.5 cm-1 para valores de menor frequência. Embora seja observado valores próximos de 2920 cm-1 para a banda vass (CH2), que é um indicativo do estado líquido de surfactantes, o que é observado nesse estudo são cristalitos de DTAB. O deslocamento da banda vsim (CH2) do DTAB é da ordem de 2 cm-1. Estas mudanças nas bandas vass (CH2) e vsim (CH2) são um indicativo da diminuição nas conformações gauche e um aumento nas conformações trans ao longo da cadeia alifática. O valor da freqüência em torno de 1472 cm-1 para a banda δ(CH2) é também um indicativo de uma maior organização na cadeia de CH2 do DTAB. Para o HPS é observado um deslocamento de 2.6 e 2.7 cm-1 para valores de maior frequência nas bandas vass (CH2) e vsim (CH2), respectivamente. A banda δ(CH2) do HPS apresenta um deslocamento de 4 cm-1 para valores de maior frequência. A variação nas bandas vass (CH2), vsim (CH2), e δ(CH2) ressalta o aumento na desorganização da cadeia alifática com o aumento na densidade de moléculas de HPS sobre o germânio. / The objective of this work is study the order level of anionic, cationic and zwitterionic surfactants with the increase of their density packing on the surface of a germanium element. The analyses were performed by a Fourier transform infrared-attenuated total reflection spectroscopy. This study shows important insights on the conformational order of sodium dodecyl sulfate (SDS), N-hexadecyl-N-N -dimethyl-3-ammonio-1-propane-sulfonate (HPS), hexadecyl-trimethylammonium bromide (CTAB) and dodecyl trimethylammonium bromide (DTAB). It is observed a shift of 1.7 and 0.9 cm-1 to higher frequency values of the CH2 asymmetric (vass (CH2)) and symmetric (vsim(CH2)) stretching bands for the SDS molecules, respectively. The latter shift to higher frequency values is associated with the disorder of the aliphatic chain due to the increase of density packing of SDS molecules on the germanium element. The CH2 scissoring band [δ (CH2)] shows a value in 1468 cm-1, which is also an indicative of conformational disorder. It is not observed any accentuated change on the vibrational frequency values of the CTAB molecules. The vass (CH2) band of the DTAB molecules is shifted 4.5 cm-1 to lower frequency values. Although it is observed values near 2920 cm-1 for the vass(CH2) band, indicating a surfactant liquid phase, it is shown in this study that there are indeed DTAB crystallites. The shift of DTAB vsim(CH2) band is around 2 cm-1. These changes in vass(CH2) and vsim(CH2) band are an indicative of a decrease in gauche conformations and an increase in all-trans conformations over the aliphatic chain. The frequency value around 1472 cm-1 for the δ(CH2) band is also an indicative of the order in CH2 chain of DTAB. It is observed a shift of 2.6 and 2.7 cm-1 to higher frequency values of vass (CH2) and vsim(CH2) bands of the HPS molecule, respectively. The δ(CH2) band of the HPS molecule presents a shift of 4 cm-1 to higher frequency values. These variations in vass (CH2), vsim(CH2), and δ(CH2) bands stand out the disorder of the aliphatic chain due to the increase of the density packing for the HPS molecules on the germanium surface.

Ultimamente têm-se buscado tratamentos menos invasivos para o câncer, como os que utilizam campos magnéticos ou luz, e dentre esses últimos, aqueles que fazem uso de materiais, geralmente metálicos, com propriedade de ressonância plasmônica de superfície. O tratamento hipertérmico encaixa-se neste perfil e já apresenta resultados promissores com nanoshells de sílica recoberta por ouro e com nanobarras de ouro maciço, apesar de pouco se saber sobre o mecanismo de ação e sobre como as vias de morte celular são ativadas em tal tratamento. A síntese das nanobarras envolve o uso do composto brometo de cetiltrimetilamônio (CTAB), o qual permanece aderido à superfície das mesmas, porém é caracterizado por apresentar extrema citotoxicidade, fato que incita a modificação do recobrimento das nanopartículas por um biopolímero mais compatível. Estudos recentes indicam que o CTAB aderido à membrana não apresenta citotoxicidade considerável, porém há poucos dados que confirmem tal hipótese na literatura. Este trabalho se propôs a investigar a via de ativação da morte celular, bem como confirmar a hipótese de que as partículas recobertas por CTAB podem ser utilizadas para tratamento antitumoral fototérmico in vivo de forma segura. Para isso, nanobarras de ouro foram sintetizadas pelo método de seeding, sendo parte delas centrifugadas e lavadas com água deionizada por três vezes para retirar o CTAB e a outra parte deixada com CTAB no meio. As partículas foram testadas in vitro pelo teste de citotoxicidade pelo [brometo de 3-(4, 5-dimetiltiazol-2-yl)-2,5-difeniltetrazólio] (MTT) nas linhagens celulares HTC, HepG2, HT-29 e 786-O, e também foram testadas quanto à sua viabilidade com o tempo decorrido desde sua síntese. Após confirmar que as nanobarras centrifugadas e lavadas podem ser utilizadas no tratamento hipertérmico sem riscos à saúde e após verificar que as seeds e as nanobarras devem ser utilizadas até 48 horas depois de sua síntese, as nanopartículas foram utilizadas para tratamento de tumor de Ehrlich (induzido no dorso de camundongos). Para isso, foram organizados quatro grupos experimentais: L (camundongos não receberam nanopartículas, irradiados com laser em 808 nm), N (camundongos receberam nanopartículas, não irradiados com laser), H (camundongos receberam nanopartículas e irradiados com laser em 808 nm) e Controles (camundongos não receberam nanopartículas nem irradiação por laser). O material tumoral foi coletado após a irradiação e submetido à análise histológica, ao teste de quimiluminescência para avaliar a lipoperoxidação de membrana e ao teste de TRAP (do inglês, Total Radical-Trapping Antioxidant Parameter) para avaliar a capacidade antioxidante total. Após a irradiação com 2 W/\'CM POT.2\' ou 720 mW/\'CM POT.2\' de intensidade, houve evidente redução do volume tumoral nos animais do grupo H tratados com laser na maior potência utilizada, com um aumento de 47ºC (temperatura final de 79ºC) observado localmente. Nos animais do grupo H tratados com laser na menor potência utilizada, os danos foram menores. Os animais dos grupos L e H apresentaram semelhante lipoperoxidação, maior que no grupo N (estatisticamente significante somente nos animais tratados com laser em intensidade de 2 W/\'CM POT.2\'), e a capacidade antioxidante dos tumores dos animais do grupo H foi elevada no protocolo com laser em 2 W/\'CM POT.2\'. Os resultados indicam que a necrose é a via de morte ativada prioritariamente neste caso e que o tratamento com as nanobarras se mostrou eficaz. / Less invasive cancer treatments, likewise those based on magnetic fields or light, are in the most common aims of researchers nowadays. Regarding light based treatments, those in which metallic, plasmonic materials are highlighted in research field. Hiperthermic treatment fits this profile, once it already presents promising results with gold-coated silica nanoshells and with gold nanorods, although little is known about its action mechanism or about how cell death pathways are activated. The compound cetyltrimethylammonium bromide (CTAB) is necessary for the nanorods synthesis, but is known to be extremely cytotoxic, fact that instigates the modification of nanorods surface coating by a compatible biopolymer. Recent studies indicate that surface-adhered CTAB does not present significant cytotoxicity, but there are few evidences to confirm this hypothesis in the literature. This study aims to investigate the cell death pathway that can be activated, as well as to confirm the possibility of safe CTAB-coated nanoparticles use in antitumor in vivo treatments. For that, gold nanorods were synthesized by the seeding method and part of them were centrifuged and washed with deionized water to eliminate CTAB of the solution and the rest remained with CTAB. The particles were tested in vitro by [3-(4, 5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) cytotoxicity test, in HTC, HepG2, HT-29 and 786-O cancer cell lines, and investigated regarding their viability through time after their synthesis. After confirming that centrifuged and washed nanorods can be used in hiperthermic therapy without health risks, and after find out that seeds and nanorods must be used within 48 hours after their synthesis, those nanoparticles were used for in vivo hyperthermic Ehrlich tumor (induced on the back of mices) treatment. Four experimental groups were organized: L (mice did not receive nanoparticles, treated with laser at 808 nm), N (mice received nanoparticles, not treated with laser), and H (mice received nanoparticles and treated with laser at 808 nm) and Controls (mice did not receive nanoparticles and were not treated with laser). A tumor biopsy was taken after laser irradiation and was subjected to histological analysis, by a chemiluminescence assay to evaluate membrane lipoperoxidation, and by Total Radical-Trapping Antioxidant Parameter (TRAP) assay as well, to evaluate total antioxidant capacity. After irradiation with laser (intensities of 2 W/\'CM POT.2\' or 720 mW/\'CM POT.2\'), there was an evident tumor volume reduction in animals of H group treated with higher power laser, with a 47ºC rise in temperature (final temperature was 79ºC) observed locally. The damages in the tumors irradiated with lower power laser were less intense. The animals of L and H groups showed similar membrane lipoperoxidation, which was more intense than in N animals (statistically significant just in the animals treated with higher intensity of radiation). The antioxidant capacity of H animals tumor was elevated also in the animals treated with higher energy. Our results indicate that necrosis is the main activated cell death pathway in this case, and that nanorods treatment is worth it.

Dans ce travail, nous avons élaboré, par voie sol-gel, un nouveau verre bioactif mésoporeux : 92S6 (92% SiO2, 6% CaO, et 2% P2O5). Cette synthèse a été développée en variant les paramètres telles que la température, la nature du tensioactif (ionique (le CTAB) ou non ionique (le P123)) et la longueur de la chaîne carbonée pour chaque type de tensioactif et en étudiant leurs effets sur les propriétés texturales du verre. Des études physico-chimiques et biologiques in vitro ont été menées sur ces biomatériaux. Par la suite, nous avons réalisé une étude structurale de l'eau confinée dans les pores du verre synthétisé qui a révélé une modification de l'ordre locale en comparaison avec l'état massique (bulk). Ceci permet un contrôle de la quantité de principe actif à incorporer dans les pores, du taux d'adsorption et de la cinétique de libération. La diffraction des Rayons X aux petits angles, l'analyse texturale par BET et les images de la microscopie électronique en transmission ont mis en évidence l'influence des paramètres de synthèse sur les propriétés texturales des verres synthétisés. En effet, l'échantillon synthétisé avec le tensioactif ionique (CTAB) présente une structure mésoporeuse non ordonné, alors que l'utilisation du tensioactif non-ionique (P123) favorise l'obtention d'un verre mésoporeux ayant une structure poreuse ordonnée. Dans le cas des verres synthétisés avec les différentes longueurs de la chaîne carbonée des tensioactifs, nous avons démontré que la longueur de la chaîne alkyle du tensioactif ionique détermine la morphologie des particules et les caractéristiques texturales des 3 verres, alors que nous avons noté une absence de différences significatives dans la texture des matériaux dans le cas des 3 verres synthétisés avec les tensioactifs non ioniques. Nous avons aussi mis en évidence l'influence de la température de synthèse sur les propriétés texturales des verres synthétisés. Nous avons démontré que la température de synthèse agit sur le diamètre des pores de manière différente selon la nature du tensioactif. L'augmentation de la température de synthèse conduit à une augmentation de la dimension des cavités dans le cas des verres synthétisés avec le P123, alors que dans le cas des verres synthétisés avec le tensioactif ionique CTAB, l'augmentation de la température de synthèse conduit à une diminution des diamètres des pores. Nous avons démontré que la morphologie des particules et les caractéristiques texturales des verres influent sur la bioactivité de ces derniers. Nous avons obtenu des verres bioactifs comme en témoigne la formation de la couche d'hydroxyapatite à leurs surfaces une fois immergés dans le SBF, ce qui explique l'intérêt des ces verres dans le domaine de la chirurgie orthopédique. / In this study, a new mesoporous bioactive glass 92S6 (92% SiO2, 6% CaO, and 2% P2O5), was prepared by sol-gel method. The purpose of this study was first to investigate the effect of synthesis parameters such as aging temperature, surfactant type and surfactant carbon chain length on the glass textural properties and then to investigate these effect on the glass bioactivity. Then, we conducted a structural study of water confined in the pores of the synthesized glass. This study revealed a change of the local order of confined water in comparison with the bulk. This allows control of drugs to be incorporated into the pores, the adsorption rate and the release kinetics. The small-angle XRD patterns (SAXRD), the Brunauer–Emmett–Teller (BET) method and the Transmission Electron Microscopy (TEM) studies evidence the influence of the structure-directing agent (ionic surfactant CTAB or non-ionic P123) in the generation of unorganized or well ordered pores in the 92S6 glass. We also demonstrated that when we synthesized glasses with a same composition using the same technique (sol-gel), in presence of surfactants with different carbon chain length, there is a direct correlation between the surfactant and textural properties and structural characteristics. As observed from small-angle XRD patterns and TEM images, synthesis at different temperatures lead to the formation of mesoporous glasses. The properties of these glasses are extremely dependent on the synthesis temperature. We demonstrated also that the bioactivity may be significantly modified by a change on glass textural properties. Finally, the samples were analyzed to quantify the apatite formation ability when soaked in SBF solution. The physico-chemical studies showed apatite-like phases formed at the glasses surface when soaked in SBF. So, our mesoporous glasses are bioactive. These characteristic mesoporous glasses will display good future applications in bone tissue repairing and engineering.