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Schnee, Vincent Patrick. « The characterization of cationic pseudostationary phases for electrokinetic chromatography ». CONNECT TO THIS TITLE ONLINE, 2007. http://etd.lib.umt.edu/theses/available/etd-05222008-102001/.
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Zhou, Xing Zhi. « Cationic polypeptide-based micelles for camptothecin delivery in lung cancer therapy ». Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3952141.
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Faivre, Valérie. « Étude des propriétés esterolytiques de complexes hydrophobes 2-hydroxymethylbenzimidazole-zn+² en présence de micelles cationiques (CTAB) ». Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL008N.
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On décrit la préparation de deux séries de 2-hydroxymethylbenzimidazoles substitués par une chaine n-alkyle (1 a 14 carbones) en position 5(6) (série I) ou 1 (série II) ainsi que la mise au point de la synthèse de nouveaux picolinates de 4-nitrophenyle (série III) porteurs d'un groupe alkoxy hydrophobe de 1 a 18 atomes de carbone. L'activité esterolytique des systèmes ligands I ou II-Zn2+ vis-à-vis des esters actives III en présence de micelles cationiques (CTAB) est comparée à celle d'un système hydrosoluble de même nature. L'étude cinétique montre l'intervention d'un seul complexe actif 2/1 pour la série I, mais de deux complexes actifs 1/1 et 2/1 pour la série II alors qu'en l'absence de micelles n'existe que le complexe 1/1. Le pouvoir esterolytique global de ces complexes est beaucoup plus élevé qu'une solution moléculaire. L'étude plus détaillée d'un ligand I montre sa complexation quasi totale; cependant la constante de vitesse apparente liée au complexe ainsi que les constantes spécifiques rapportées à la pseudo-phase micellaire sont plus faibles qu'en l'absence de micelle. Cette forte diminution de réactivité peut être attribuée à la formation plus difficile du complexe ternaire ligand/-Zn++/ester, intermédiaire dans la réaction d'esterolyse
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Ergican, Erdogan. « Molecular level separation of arsenic (V) from drinking water using cationic micelles and ultrafiltration membrane ». abstract and full text PDF (free order & ; download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3210067.
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Skoglund, Sara. « Self-assembly in mixtures of an anionic and a cationic surfactant : A comparison between static light scattering and cryotransmission electron microscopy ». Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34032.
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Surfactants self-assemble into aggregates above a certain concentration. In this work mixtures of the cationic surfactant cetyltrimetylammonium bromide (CTAB) and the anionic surfactant sodium octyl sulfate (SOS) were investigated systematically. The measurements were accomplished by combining the two complimentary techniques static light scattering (SLS) and cryo-transmission electron microscopy (CRYO-TEM). It was found that CTAB-rich samples contain large threadlike micelles rather close to mole fractions where vesicles start to form. The mole fraction x of the surfactant in excess in the aggregates was calculated and it was found that it differs a lot from the mole fraction in the bulk, and the transition from micelles to vesicles occurs when x is about 0.7. In the SOS-rich samples small globular micelles were observed that transform into vesicles upon dilution. Some of the samples rich in SOS were found to contain open vesicles with CRYO-TEM and the reasons for this behavior have been discussed. One question that needs to be further investigated is whether or not these structures are the result of some kind of distortion of the equilibrium process during sample preparation in connection with CRYO-TEM measurements. In most cases the two methods showed consistent results and trends, but for some samples differences could be observed.
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Kashapov, Ruslan R., Tatiana N. Pashirova, Sergey V. Kharlamov, Albina Yu Ziganshina, Elena P. Ziltsova, Svetlana S. Lukashenko, Lucia Ya Zakharova, Wolf D. Habicher, Shamil K. Latypov et Alexander I. Konovalov. « Novel self-assembling system based on resorcinarene and cationic surfactant ». Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-138802.
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Mixed association of calix[4]resorcinarene with ethyl sulfonate groups on the lower rim and dimethylaminomethyl groups on the upper rim (CR) and cationic surfactant 4-aza-1-hexadecyl-azoniabicyclo[2.2.2]octane bromide (DABCO-16) is studied by methods of tensiometry, conductometry, potentiometry and NMR spectroscopy at fixed CR concentration and varied surfactant concentration. Beyond ca. 0.4 mM of DABCO-16, mixed aggregates enriched by CR are proved to be formed due to electrostatic forces, while beyond ca. 5 mM, aggregates enriched by surfactant occur due to the hydrophobic effect. Spectrophotometry monitoring of the solubilization of a hydrophobic dye, Orange OT, demonstrated that only the second type of mixed aggregate enriched by DABCO-16 is capable of binding the organic probe, while the mixed system where the surfactant is a minor component shows no binding capacity towards Orange OT. This finding can be used for the design of nanocontainers with controllable binding/release propertiesDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Kashapov, Ruslan R., Tatiana N. Pashirova, Sergey V. Kharlamov, Albina Yu Ziganshina, Elena P. Ziltsova, Svetlana S. Lukashenko, Lucia Ya Zakharova, Wolf D. Habicher, Shamil K. Latypov et Alexander I. Konovalov. « Novel self-assembling system based on resorcinarene and cationic surfactant ». Royal Society of Chemistry, 2011. https://tud.qucosa.de/id/qucosa%3A27782.
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Mixed association of calix[4]resorcinarene with ethyl sulfonate groups on the lower rim and dimethylaminomethyl groups on the upper rim (CR) and cationic surfactant 4-aza-1-hexadecyl-azoniabicyclo[2.2.2]octane bromide (DABCO-16) is studied by methods of tensiometry, conductometry, potentiometry and NMR spectroscopy at fixed CR concentration and varied surfactant concentration. Beyond ca. 0.4 mM of DABCO-16, mixed aggregates enriched by CR are proved to be formed due to electrostatic forces, while beyond ca. 5 mM, aggregates enriched by surfactant occur due to the hydrophobic effect. Spectrophotometry monitoring of the solubilization of a hydrophobic dye, Orange OT, demonstrated that only the second type of mixed aggregate enriched by DABCO-16 is capable of binding the organic probe, while the mixed system where the surfactant is a minor component shows no binding capacity towards Orange OT. This finding can be used for the design of nanocontainers with controllable binding/release properties.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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Pires, Paulo Augusto Rodrigues. « Síntese e propriedades de soluções de tensoativos catiônicos derivados de (3-dimetilaminopropil)amidas de ácidos carboxílicos ». Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/46/46135/tde-06102003-163601/.
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Duas séries homólogas de tensoativos foram sintetizadas, os cloretos de benzil-(3-acilaminopropil)dimetilamônio, RCONH(CH'ind.2')3N'pot.+'(CH'ind.3')]pot.2'CH'pot.2'C'pot.6'H'pot.5'Cl'pot.-'e (3-acilaminopropil)trimetilamônio, RCONH[(CH'pot.2')]'ind.3'N'pot.+'(CH'ind.3')'pot.3'Cl'ind. -' , onde RCO = C'ind.10' a C'ind.16'. A síntese foi realizada a partir de precursor comum, RCONH(CH'ind.2')'pot.3'N'(CH'ind.3')ind.2', sendo a quaternização feita pela reação com cloreto de benzila e iodeto de metila (seguido de troca iônica), respectivamente. Investigou-se a adsorção na interface solução/ar, a micelização e a estrutura dos agregados formados. Os resultados foram comparados com os de tensoativos catiônicos. Algumas das propriedades micelares das séries estudadas (ex: concentrações micelares críticas, graus de dissociação, números de agregação) tem valores na mesma faixa de grandeza dos outros tensoativos catiônicos com o mesmo tamanho de cadeia hidrofóbica. Outras, por exemplo, a energias livres de Gibbs de adsorção e micelização são diferentes (mais favoráveis). Os resultados apontam para o fato de que o grupo 3-amidopropila, [-CO-NH-CH'ind.2'-CH'ind.2'-CH'ind.2'-], quando inserido na molécula do tensoativo, acaba constituindo parte do seu grupo hidrofílico e facilita a micelização do mesmo. A polaridade microscópica da água interfacial foi determinada usando sondas solvatocrômicas e mostra que a água interfacial é menos polar que água 'bulk'.The following surfactants have been synthesized: benzyl-(3-acyl-aminopropyl)dimethylammonium chloride, RCONH(CH'ind.2')'ind.3'N'pot.+'(CH'ind.3')'ind.2'CH'ind.2'C'ind.6'H'ind.5' Cl'pot.-' and (3-acylaminopropyl) trimethylammonium chloride, RCONH(CH'ind.2')'ind.3'N'pot.+'(CH'ind.3')'ind.3' Cl'ind.-', where RCO = C'ind.10' to C'ind.16'. The two series have been synthesized from the precursor RCONH(CH2)3N(CH3)2, by quaternization with benzyl chloride, and/or methyl iodide (followed by ion exchange), respectively. Adsorption at solution/air interface and micellization in aqueous solution has been studied, and the results compared with those of other cationic surfactants. Some properties, e.g., critical micelle concentrations, degrees of micelle dissociation, and aggregation numbers are similar to those of other cationic surfactants of equivalent hydrophobic chain length. The Gibbs free energies of adsorption at solution/air interface, and of micellization are, however, more favorable. The group [-CO-NH-CH'ind.2'-CH'ind.2'-CH'ind.2'-] is a part of the interface, and lead to favorable micellization. The microscopic polarity of interfacial water has been measured by appropriate solvatochromic probes, and is less than that of bulk water.
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Ashrafizadeh, Seyed Nezameddin. « Cation exchange with reverse-micelles ». Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61109.
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Experimental and theoretical studies on the extraction of the cation K$ sp+$ and Mg$ sp{++}$ from a bulk aqueous phase to an organic phase using the water/dinonylnaphthalene sulfonic acid (HD)/heptane reverse-micellar system was conducted. The counter ion of the surfactant, H$ sp+$, was exchanged with the alkali metal cations in the aqueous phase. Two different types of experiments were conducted. The first set involved a constant total normality of ions while the second investigated the effect, of varying the normality of ions. Electrolyte solutions with molarities ranging from 0 to 1 were contacted with a reverse-micellar organic containing different concentrations of surfactant with different types of counter ions.The HD reverse-micellar extraction system exhibited behavior similar to that of conventional ion-exchange resin systems. A preferential extraction for Mg$ sp{++}$ over K$ sp+$ was observed. The efficiency of the extraction was high for low salt concentrations and it was independent of surfactant concentration. The amount of water uptake was low, with W$ sb{o}$ ranging between 4 and 10. For a wide range of salt and surfactant concentrations W$ sb{o}$ was independent of surfactant concentration. The HD surfactant showed a low solubility in the aqueous phase.
The results of the equilibrium partition experiments were correlated using a thermodynamic model. Interaction parameters determined from binary system experimental data were used to predict the ternary system partition behavior. The ternary system predictions were compared with experimental results and found to be satisfactory.
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Gélinas, Stéphanie. « Micellar-enhanced ultrafiltration using a twin-head cationic surfactant ». Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23262.
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In Micellar-Enhanced Ultrafiltration (MEUF), a surfactant is added to a wastewater stream containing an organic solute. Most of the solute is solubilized in micelles, which are aggregates of surfactant molecules, formed in the feed solution. Separation is achieved through retention of the micelles by an ultrafiltration membrane. Since much of the solute is within the micelles, a membrane with a molecular weight cut off (MWCO) much larger than the molecular weight of the solute is used. Although some unsolubilized solute and surfactant monomers pass through the membrane, the use of a surfactant with a low critical micelle concentration (CMC) ensures little contamination of the permeate by surfactant monomers.Solubilization tests and MEUF experiments were performed with an aqueous feed solution of benzoic acid (molecular weight 122) and Rhodameen T12/90 (molecular weight 798), a twin-head, cationic tertiary amine surfactant. This surfactant has an 18 carbon hydrophobic tail and two hydrophilic polyoxyethylene heads. The equilibrium solubilization of benzoic acid by surfactant solutions was measured by semiquilibrium dialysis. The maximum solubilization was nearly one mole of benzoic acid per mole of Rhodameen.
MEUF was carried out in hollow fiber polysulfone membrane units with MWCO of 5,000 and 30,000. The permeate flux and overall rejection of benzoic acid and surfactant were measured for different initial feed compositions and initial surfactant concentrations under varying transmembrane pressures (TMP). The flux increased with TMP and decreased with Rhodameen concentration, but was not affected by the benzoic acid concentration. The highest rejections of benzoic acid (90%) and Rhodameen (95%) were obtained when the molar ratio of surfactant to solute in the feed was 1.2.
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Bertoncini, Clelia Rejane Antonio. « Efeito de aditivos em micelas cationicas ». reponame:Repositório Institucional da UFSC, 1989. http://repositorio.ufsc.br/xmlui/handle/123456789/75544.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciencias Fisicas e MatematicasMade available in DSpace on 2012-10-16T02:16:38Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-08T16:26:26Z : No. of bitstreams: 1 78937.pdf: 2437398 bytes, checksum: 1ee043098f93193a5fadb8fd46ed69b3 (MD5)
Micelas catiônicas de brometo e hidróxido de cetiltrietilamônio (CTEABr e CTEAOH) têm suas propriedades físico-químicas afetadas pela adição de n-butanol (BuOH). Através de medidas de condutividade, a 25oC, foram determinados os valores de CMC e a destes detergentes, em soluções aquosas na presença de BuOH. A CMC diminui em baixas concentrações e aumenta em altas concentrações de BuOH, enquanto que o valor de a aumenta continuamente com adição de BuOH. Os efeitos da adição de BuOH e NaBr nas propriedades catalíticas de CTABr e CTEABr, a 25oC, foram estudados através de medidas de constantes de velocidade para a reação de b-naftalenossulfonato de metila com íon brometo, sendo que a constante de velocidade diminui com a adição de BuOH. Os dados cinéticos podem ser explicados considerando que: i) a concentração de contra-íons reativos na superfície micelar não é constante, ou seja muda com a adição de BuOH e/ou NaBr; ii) a constante de ligação do substrato à micela depende da BuOH; iii) existe uma constante de velocidade para a decomposição espontânea do substrato e iv) a constante de ligação do BuOH à micela é descrita através de uma constante de distribuição de valor K = 1M-1. Feitas essas considerações, foram calculados valores de km = 9,1 x 10-4 de distribuição para o CTABr e km = 13,8 x 10-4 s-1 para o CTERABr, os quais ajustam perfeitamente os dados experimentais.
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Wang, Wenhua 1960. « Reverse micellar extraction of amino acids using the two-tailed cationic surfactant DODMAC ». Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28954.
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Reverse micelles have been formed for the first time with a two tailed cationic surfactant, dioctyldimethyl ammonium chloride (DODMAC), in alcohol/isooctane mixtures. The effect of different alcohols and salts on water uptake of the DODMAC reverse micelles has been studied.The effects of pH and of the concentrations of amino acid, NaCl, DODMAC and l-decanol on the reverse micellar extraction of aspartic acid, glutamic acid and threonine from aqueous salt solutions were determined by phase contact experiments. The concentrations of all ionic species in the aqueous phase were measured and the corresponding concentrations inside the reverse micelles were obtained by material balances and the condition of electrical neutrality. The results show that the amino acids were mainly extracted through an ion exchange mechanism. Important factors which dominate the amino acid extraction are the net charge of amino acid, the competition among anions, the dissociation equilibrium of DODMAC and the water uptake in the reverse micelles. The ionic species in the reverse micelles tend toward their undissociated states as the water uptake by the reverse micelles decreases.
The renormalization of Guggenheim's canonical partition function to satisfy the limits of order and disorder has been used to generate excess Gibbs energy models for liquid mixtures. Under well defined assumptions, the contributions to the activity coefficients arising from the new partition function correspond exactly with those given by existing semi-empirical models.
A thermodynamic model has been developed to calculate the concentrations of all ionic species in both the aqueous and the reverse micellar phases. With this model it is possible to study the effect of changes of extraction variables, such as the concentrations of salt, surfactant and cosurfactant, in the extraction of amino acids by reverse micelles. The model has been tested by performing flash calculations for the system DODMAC, l-decanol isooctane, NaCl an amino acid and water. Three different amino acids were considered. The calculated results are in good agreement with the experimental data.
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Peroza, Meza Carlos Arturo. « Factors affecting the alkaline hydrolysis of carbaryl in the presence of cationic surfactants ». Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/6248.
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Alkaline degradation of Carbaryl in the presence of CTAB micelles has been reported as the most efficient method; however, the factors accounting for it are not yet clear. The main objective of this work was to study some of the factors affecting the alkaline degradation of Carbaryl in the presence of cetyl trimethylammonium bromide (CTAB). Three specific aims were researched in order to address the main objective.
Solubility studies, UV-vis, fluorescence, and 1D-HNMR and 2D-HNMR spectroscopies were used to research the solubilization of carbaryl in CTAB micelles. Solubility studies showed that carbaryl partitions into CTAB micelles with a binding constant of 553 ± 8 M-1, and each mole of micellized surfactant incorporates about 0.336 moles of carbaryl. Spectroscopy studies showed that carbaryl does not interact electrostatically with micelles but does through van der Waals interactions. 1D-HNMR and 2D-HNMR indicated solubilization in the Stern layer, oriented with its hydrophilic moiety towards the Goüy-Chapman layer and the hydrophobic moiety towards the core of the micelle.
Kinetic studies as a function of the surfactant concentration along with micellar kinetic models were used to calculate micellar rate constants (k’M) for each of four different cationic surfactants: cetyl trimethylammonium hydroxide (CTAOH), cetyl trimethylammonium bromide (CTAB), cetyl trimethylammonium chloride (CTACl), and cetyl pyridinium chloride (CPCl), and compared to the corresponding rate constants (k’W) in water; the results in all cases showed k’M / k’W > 1. This fact led to the conclusion that additional factors beyond solubilization of substrates are playing a role. Solubility studies revealed the following binding constant order and solubilization capacity order: CPCl > CTAOH ≈ CTAB > CTACl, CPCl > CTAOH ≈ CTAC > CTAB, indicating that for CPCl, Coulombic interactions, such as charge-transfer complexes, may be favoring the concentration effects, while for other surfactants, such as CTAOH, the [–OH] as the micelle counterion increases Carbaryl’s concentration in the Stern layer compared to its bulk concentration. In contrast, large, weakly-hydrated polarizable ions such as Br– displace hydrophilic ions, providing less enhancement.
Kinetic experiments as a function of the surfactant head’s charge led to the conclusion that cationic and zwitterionic surfactants have a catalytic effect of the alkaline hydrolysis of carbaryl, while nonionic and anionic surfactants have inhibitory effects: kobs (cationic) > kobs (zwitterionic) > kobs(nonionic) > kobs (anionic). A similar order for solubility parameters (Ks and SC) was observed from equilibrium solubility studies. Experiments as a function of the polarity of the medium in the presence of both polar and nonpolar solvents showed that the hydrolysis rate is inversely proportional to the medium polarity. Ionic strength experiments showed that the hydrolysis rate is inversely proportional to the ion concentration.
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Lardet, Dominique. « Influence des milieux micellaires sur la solvolyse des radicaux cations des dérivés de la phénothiazine ». Lyon 1, 1986. http://www.theses.fr/1986LYO19014.
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En milieu homogene aqueux ou hydroorganique, ainsi que dans les milieux micellaires etudies, la solvolyse des radicaux cationiques de la methyl-10 phenothiazine et de la chlorpromazine s'effectue suivant un mecanisme de semi-regeneration quelque soit le tampon utilise. L'effet catalytique observe est principalement du a l'incorporation du substrat neutre dans les micelles
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Sanson, Nicolas. « Assemblages induits de copolymères à blocs double hydrophiles (DHBC) et de cations métalliques multivalents : Nouveaux précurseurs de nanoparticules hybrides ». Montpellier 2, 2005. http://www.theses.fr/2005MON20037.
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Ben, Chaabane Tahar. « Transfert d'électron en micelles et vésicules : effet du potentiel électrique interfacial ». Paris 11, 1987. http://www.theses.fr/1987PA112188.
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Détermination du rôle du potentiel électrique interfaciale delta psi micellaire (laurylsulfate de sodium) ou vésiculaire (dipalmitylphosphate, dhp) sur les trois types de réactions photochimiques ou thermiques suivants : photo ionisation de la tetramethylbenzidine (tmb), declin de tmb(+), photo transfert d'électron en vésicules dhp
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Haramagatti, Chandrashekara Rajashekara. « Structure, dynamics and phase behaviors of cationic micellar solutions raman and neutron scattering study of alkyltrimethylammonium bromides / ». [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982482361.
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Hassan, Raeisi Azadeh [Verfasser]. « Investigation of hydrophobically modified polyacrylamide gels prepared in micellar solutions of a cationic surfactant / Azadeh Hassan Raeisi ». Clausthal-Zellerfeld : Universitätsbibliothek Clausthal, 2014. http://d-nb.info/1051940516/34.
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Belmajdoub, Abdelaly. « Étude comparative des systèmes micellaires bromure de cetyltrimethylammonium/eau lourde et bromure de cétyltriméthylammonium/fromamide par relaxation magnétique nucléaire multichamp/multifréquence des isotopes **(1)H, **(2)H, **(14)N, **(13)C, et **(17)O ». Nancy 1, 1988. http://www.theses.fr/1988NAN10250.
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Études des propriétés du formamide en tant que substitut de l'eau dans les systèmes micellaires et les phases lyotropes et description quantitative de l'agrégation des tensioactifs en solution non aqueuse
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Leifsdotter, Josefine. « Investigation of the micelle-to-vesicle transition in mixtures of an anionic and a cationic surfactant : the effect of adding salt ». Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-158474.
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Catanoinic systems spontaneously form micelles and vesicles, which are self-assembled spherical structures made up by surfactants. In the core of the micelle a drug, or other organic substance, can be kept to stabilize it when placed in an aqueous environment. The micelle-to-vesicle transition corresponds to the moment when the drug is releases, and understanding which factors that trigger this transition is thus of great interest for the pharmaceutical industry. In this study the micelle-to-vesicle transition in water and the effect of salt were studied for the systems 95 mol% SDS/DDAB and 95 mol% SDeS/DDAB with different total concentrations. The static light scattering measurements showed that the micelle-to-vesicle transition for the system 95 mol% SDS/DDAB was shifted to lower total concentrations both when 50 mM NaBr and 100 mM NaBr were added, and that the transition was unaffected by changing the anionic surfactant from SDS to SDeS when no salt had been added. A phase separation was observed when 50 mM NaBr was added to 95 mol% SDeS/DDAB (the Krafft point was probably reached), and when 100 mM NaBr was added to the same system the sample remained opaque one week after mixing the sample and also after heating it to 40°C in a water bath. The curve for sample 95 mol% SDS/DDAB 1/8192 mM + 100 mM NaBr was oscillating implying possible defects in the vesicle membrane. The cryo-TEM images confirmed the light scattering results and additionally showed that at higher total concentrations agglomeration occurred, while whenever salt was added less vesicles seemed to appear, while both discs and broken vesicles were present suggesting that the disc structure is preferred over the spherical structure when salt is present. Also a vesicle inside another vesicle was discovered for the sample 0.95 SDS/DDAB 3.75 mM + 50 mM NaBr. The mole fraction of anionic surfactant in the aggregates (x) was calculated using a MATLAB code based on the Poisson-Boltzmann theory. The results from the calculations showed that a higher amount of SOS was needed for the system 0.95 SOS/CTAB than the amount of SDS and SDeS needed for the systems 0.95 SDS/DDAB and 0.95 SDeS/DDAB when forming aggregates, indicating that a shorter chain of the anion and the higher spontaneous curvature of the cation leads to a higher curvature. Also a larger amount of cation was needed when the tail was single than when it was double in order to form stable spherical structures. Finally, as the total concentration decreased the x value also decreased in all cases, thus the spontaneous curvature was decreased.
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Dupont-Leclercq, Laurence Rubini Patrice Henry Bernard. « Etude cinétique et thermodynamique de réactions d'échange de protons et de complexation de cations métalliques en milieu micellaire ». S. l. : S. n, 2009. http://www.scd.uhp-nancy.fr/docnum/SCD_T_2009_0057_DUPONT-LECLERCQ.pdf.
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Lin, Zhiqing. « The effect of chemical structures of cationic surfactants or counterions on solution drag reduction effectiveness, rheology and micellar microstructure / ». The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488203552779718.
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Amado, André Miele. « Agregação da acridina laranja em soluções aquosas e na interação com micelas de SDS ». Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-17042013-095936/.
Texte intégralRésumé :
Esse trabalho apresenta um estudo experimental de agregação da Acridina Laranja (AL) em solução aquosa homogênea e na sua interação com o surfactante Sodium Dodecyl Sulfate (SDS). Este estudo foi realizado com o objetivo de definir estruturas e características temporais de formação de agregados de compostos orgânicos com sistema desenvolvido de conjugação-, usados como fotossensibilizadores e marcadores de estruturas biológicas, em sua interação com nanoestruturas heterogêneas. A informação sobre as características de agregação de fotossensibilizadores é importante devido à influência deste processo na eficácia de suas aplicações práticas, em particular na biologia e medicina. A AL foi escolhida como modelo devido aos seguintes motivos: AL é um composto bem conhecido e várias de suas características já estão bem estabelecidas na literatura; Possui alto rendimento quântico de fluorescência, alta fotoatividade, alta afinidade com estruturas biológicas (membrana celular, DNA e RNA, em particular), por isso a AL é amplamente usada como marcador fluorescente e fotossensibilizador em fototerapia; AL possui a tendência de formar agregados em solução aquosa; A agregação da AL modifica seus espectros de absorção e de fluorescência, diminui o tempo de vida e o rendimento quântico de seus estados excitados. Isso a torna um modelo útil para o estudo do fenômeno da agregação. Foram analisados os espectros de absorção óptica, de fluorescência e de espalhamento ressonante da luz em regime estático e em função do tempo, como também o espalhamento dinâmico da luz para várias concentrações de AL e de SDS. Observamos que: em soluções aquosas a AL forma agregados tipo H; O aumento da concentração de AL em soluções homogêneas induz o aumento do número de agregação; A presença do sal estimula a agregação devido à diminuição da repulsão eletrostática entre as moléculas de AL; O SDS em concentrações acima de 60uM estimula a agregação da AL induzindo a formação de agregados mistos nAL+mSDS; A estrutura dos agregados nAL+mSDS é flexível e instável; Os agregados mistos possuem uma dinâmica de transformações caracterizada por quatro componentes, a primeira com tempo característico < 36 s e os outros três com tempos que variam de minutos até algumas horas; A agregação diminui a intensidade da fluorescência da AL e aumenta a intensidade do ERL; Em altas concentrações o SDS diminui o número de agregação da AL chegando finalmente à sua forma monomérica ligada com os agregados e/ou micelas de SDS; Se comparado com a AL em solução aquosa homogênea, a ligação de monômeros da AL com micelas de SDS aumenta a intensidade da sua fluorescência; O estudo demonstra que a agregação afeta a eficácia dos fotossensibilizadores em aplicações. Tal fato deve ser tomado em consideração, especialmente devido à sua dinâmica prolongada, pois as características dos fotossensibilizadores se modificam continuamente durante o seu uso.In this work we present an experimental study of Acridine Orange (AO) aggregation in homogeneous aqueous solutions and its interaction with a surfactant Sodium Dodecyl Sulfate (SDS). The objective of this study was to define the structure and temporal characteristics of aggregates of organic compounds with developed-conjugated system, used as photosensitizers and probes of biological structures, in its interaction with heterogeneous nano-structures. The information on photosensitizer aggregation characteristics is important as this process would affect its efficiency in practical applications, in biology and medicine, in particular. AO was chosen as a model for the following reasons: AO is a known compound with various characteristics well described in literature; AO has a high fluorescence quantum yield, high photoactivity, high affinity to biological structures (cell membrane, DNA and RNA, in particular), therefore, AO is widely used as a fluorescent marker and a photosensitizer in phototherapy; AO possesses a tendency to aggregate in aqueous solution. The aggregation of AO modifies essentially its absorption and fluorescence spectra, decreases the lifetime and quantum yield of its excited states. This makes AO a suitable model for studying the aggregation phenomenon. We have analyzed optical absorption, fluorescence and resonant light scattering spectra in the static mode and as a function of time as well as the dynamic light scattering for various AL and SDS concentrations. It was found that: in aqueous solutions AO forms H aggregates; The increase in concentration of AO in homogeneous solutions induces an increase in its aggregation number; The presence of salt stimulates aggregation due to decrease of electrostatic repulsion between AO molecules; The SDS concentrations above 60 M stimulate AO aggregation inducing the formation of mixed nAL + mSDS aggregates; Mixed nAL + mSDS aggregates are characterized by flexibility and instability; Transformation dynamics of the mixed aggregates is characterized by four components, the first one with a characteristic time <36 and the other three with times ranging from minutes to several hours; AO aggregation in a solution decreases its fluorescence and increases the resonant light scattering intensities; SDS at high concentrations reduces AO aggregation number until its monomeric form bound with SDS aggregates and / or micelles; AO monomers bound with SDS micelles possess higher fluorescence intensity as compared with that in homogeneous aqueous solutions. Our research shows that aggregation modifies efficacy of photosensitizers at their application. This has always to be considered especially due to its prolonged dynamics as the photosensitizer characteristics are modifying continuously during its application.
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Wang, Bin. « Utility of Cationic and Anionic Chiral Surfactants in Capillary Electrophoresis (CE) and CE Coupled to Mass Spectrometry (CE-MS) ». Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/chemistry_theses/16.
Texte intégralRésumé :
The research presented in this thesis involves the application of chiral cationic and anionic surfactants for simultaneous enantioseparation of structurally similar compounds in capillary electrophoresis (CE) and CE coupled to mass spectrometry (CE-MS). The first chapter briefly introduces the fundamentals of CE and CE-MS, emphasizing the micellar electrokinetic chromatography (MEKC) and MEKC-MS techniques, as well as ionic liquids (ILs) and affinity CE (ACE). In chapter 2, a mixture of five racemic profen (PROF) drugs are simultaneously separated with the combined use of 2,3,6-tri-O-methyl-β-cyclodextrin (TM-β-CD) and IL-type surfactant, N-undecenoxycarbonyl-L-leucinol bromide (L-UCLB). Enantioseparations of these PROFs are optimized using a standard recipe containing 35.00 mM TM-β-CD, 5.00 mM sodium acetate at pH 5.0, and varying the concentration as well as chain length of the IL surfactants. The batch-to-batch reproducibility of L-UCLB is found to be acceptable in terms of enantiomeric resolution, and migration time. A competitive inhibition mechanism is proposed to investigate the ternary interactions among TM-β-CD, ILs, and PROFs. The apparent binding constant of TM-β-CD to L-UCLB is estimated by nonlinear and linear plotting methods. The binding constants of one representative PROF (e.g., fenoprofen) to TM-β-CD and to L-UCLB are estimated by a secondary plotting approach. The R- and S-fenoprofen having different binding constant values, resulting in the enantioseparation due to the synergistic effect of TM-β-CD and L-UCLB. The R- and S-configurations of barbiturates display differences in potency and biological activity. In Chapter 3, a multivariate MEKC-ESI-MS approach for the simultaneous analysis of the racemic mixture of three barbiturates is presented. The chiral selector employed is the polymeric surfactant polysodium N-undecenoxycarbonyl-L-isoleucinate. The central composite design is used to optimize the chiral resolution, decrease the total analysis time, and improve the ESI-MS signal-to-noise ratio for these barbiturates. In preliminary experiments, the ranges of the factors investigated in the multivariate approaches are determined. Then the multivariate optimizations are conducted to determine the best overall chiral resolution with shortest possible run times for barbiturates. The limit of detection of ESI-MS is several folds higher compared to the UV detection. The predicted optimum results are in good agreement with the experimental data.
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Ngo, Thi Huong Viet. « Synthèse et propriétés amphiphiles de lipides cationiques à chaîne alkyle ou perfluoroalkyle polyfonctionnels en milieu aqueux ». Thesis, Tours, 2010. http://www.theses.fr/2010TOUR4021.
Texte intégralRésumé :
Les composés amphiphiles, N-[Iodures de 3-(diméthylamino) propyl]-perfluoroalcanes amides (Fn-AH3-AmI) et Na,Nb-Bis [Iodures de 3-(diméthylamino) propyl]- perfluoroalcanes diamides (Fn(AH3-AmI)2) ont étéobtenus à partir des (di)esters et de la N,N’-diméthyl-3-propylamine puis parquaternisation par l’iodure de méthyle.Le comportement des composés à une tête cationique Fn-AH3-AmI (n = 8,10, 12, 14) en milieu aqueux a été examiné en étudiant l’effet de latempérature T, d’électrolyte KI et d’éthanol, ainsi que l’effet de la longueur etde la nature chimique de la chaîne hydrophobe (perfluorée ouhydrocarbonée) sur les propriétés de surface et d’agrégation. Les composéshydrocarbonés forment des micelles. Micelles et vésicules coexistent dans lecas des homologues fluorés.Les propriétés tensioactives et agrégatives des bolaformes Fn(AH3-AmI)2 (n =6, 8, 10) ont été examinées en fonction de T, KI et de la structure de lachaîne hydrophobe. La formation des agrégats est supposée être associée àla capacité de repliement des bolaformes.Les composés Fn-AH3-AmI et Fn(AH3-AmI)2 sont impliqués dans laformulation de vésicules dont la taille est examinée en fonction de la teneuren co-lipide 1,2-dioléoyl-sn-glycéro-3-phosphatidyléthanolamine (DOPE)Amphiphilic compounds N,N,N-trimethyl-(3-N-perfluoroalkylamidopropyl)ammonium iodide (Fn-AH3-AmI) and N1,N12-Bis [3-(trimethylammonium)propyl iodide]- perfluoroalcane diamide (Fn(AH3-AmI)2) are obtained byreaction between (di)esters and 3-N,N-dimethyl-1-propylamine and thenquaternization by methyl iodide.The aqueous solution behaviour of one head compounds Fn-AH3-AmI interms of surface and aggregative properties is examined as a function oftemperature T, KI amount and ethanol, and also by varying their tail length(n = 8, 10, 12, 14) and their hydrocarbon or perfluorocarbon type.Hydrocarbon compounds associate into micelles. Micelles and vesicles cancoexist in the case of the perfluorocarbon homologues.The surface and aggregatives properties of the bolaforms Fn(AH3-AmI)2 (n =6, 8, 10) are also examinated as a function of T, KI and the hydrophobic tailstructure. The aggregate formation is thought to be attributed to the bendingability of the bolaforms.Fn-AH3-AmI and Fn(AH3-AmI)2 compounds are involved in the formulationof vesicles whose size is examinated as a function of the co-lipid 1,2-dioleoylsn-glycero-3-phosphatidylethanolamine (DOPE) amount
26
Dupont-Leclercq, Laurence. « Etude cinétique et thermodynamique de réactions d'échange de protons et de complexation de cations métalliques en milieu micellaire ». Thesis, Nancy 1, 2009. http://www.theses.fr/2009NAN10057/document.
Texte intégralRésumé :
L’objectif de ce travail est la compréhension des variations des constantes thermodynamiques et cinétiques de protonation et de complexation en milieu micellaire par rapport au milieu aqueux continu. Pour ce faire, deux types de systèmes micellaires ont été considérés : - Soit le réactif étudié s’auto-organise spontanément en micelles : nous avons ainsi étudié les cinétiques de transfert protonique sur des sels d’ammonium amphiphiles et les réactions de complexation du Cu(II) par des dérivés de carbohydrates amphiphiles (alkylpolyglucosides). - Soit le réactif étudié est mis en présence de micelles : nous nous sommes ainsi intéressés aux équilibres acido-basiques et aux réactions de complexation du Cu(II) mettant en jeu des dérivés originaux, les acides alkylamide-tartriques, en présence de micelles non ioniques. De profondes modifications des caractéristiques cinétiques et thermodynamiques des réactions étudiées ont été mises en évidence. Celles-ci ont été interprétées d’un point de vue fondamental et exploitées afin de développer de nouvelles techniques analytiques : de mesure de CMC, de détermination de constantes de partage eau/micelles, d’identification des espèces solubilisées dans les micelles et d’interprétation des variations de rendements d’extraction micellaire du Cu(II) par ultrafiltration (Micellar Enhanced-Ultrafiltration), en fonction du pH. Ces travaux mettent en jeu des techniques d’investigation variées telles que la résonance magnétique nucléaire (dynamique et statique), la pH-métrie, les spectroscopies UV-visible et dichroïsme circulaire ou l’ultrafiltration micellaire. Une réflexion sur l’utilisation de ces techniques en milieu micellaire est proposéeThis study aims at understanding the influence of micellar media on the thermodynamics and the kinetics of cations complexation and proton transfer. Two kinds of systems were studied: - On the one hand, we studied molecules which self-organize in micelles such as amphiphilic ammonium salts, to investigate the kinetics of proton transfer and alkylpolyglucosides, to determine the thermodynamics of Cu(II) complexation. - On the other hand, we analysed acid-base reactions and Cu(II) complexation involving original tartaric acid derivatives which can be solubilized in non-ionic micelles. Deep modifications of thermodynamics and kinetics parameters in the presence of micelles were demonstrated and interpreted from a fundamental point of view. We took advantages of these changes to develop new analytical techniques for CMC measurements, determination of water-micelles partition constants, identification of species solubilized in the micellar pseudophase and interpretation of the variation of Cu(II) micellar extraction yields as a function of pH. To perform these experiments, various analytical techniques were used: nuclear magnetic resonance (Dynamic and Static NMR), pHmetry, UV-visible and circular dichroism spectroscopies, micellar enhanced-ultrafiltration. The use of these techniques in micellar media was discussed
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Bate, Bate. « Engineering behavior of fine-grained soils modified with a controlled organic phase ». Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39627.
Texte intégralRésumé :
Organic materials are ubiquitous in the geologic environment, and can exert significant influence over the interfacial properties of minerals. However, due to the complexity in their structure and interaction with soil solids, their impact has remained relatively unquantified. This study investigated the engineering behaviors of organoclays, which were synthesized in the laboratory using naturally occurring clay minerals and quaternary ammonium compounds of controlled structure and density of loading. Organic cations were chosen to study the effects of functional group structure and size.
The laboratory investigation showed that the presence of the organic cations on the mineral surfaces led to increased hydrophobicity of all clays tested. Conduction studies on the electrical, hydraulic, and thermal properties of the organoclay composites suggested that increasing the total organic carbon content resulted in decreased electrical and thermal conductivity, but increased hydraulic conductivity, due to the reduced swelling of the base clay mineral phase. Electrokinetic properties of the organoclays illustrated that compared with the clay's naturally occurring inorganic cations, exchanged quaternary ammonium cations were more likely bound within a particle's shear plane. Consequently, organoclays had less negative zeta potential than that of unmodified bentonite. Increasing the length of one carbon tail was more effective at binding organic cations within the shear plane than increasing the size of the cation, when compared on the basis of total organic carbon content.
In terms of large strain strength, the modified organic clays exhibited increased shear strength, in part owing to the reduction in water content caused by the presence of the hydrophobic organic layering. Shear strength increased with single carbon tail length or with cation size, although the latter effect tended to reach a plateau as the length of the four short cation tails increased from 2 to 4. In terms of small strain behavior, the shear modulus was shown to be a function of the total organic carbon content. It is believed that number of particle contacts increased as the organic carbon content increased. Stiffness increased as either the size of the cation or the total organic carbon content was increased. Damping also increased as the organic loading was increased, with the organic phase acting as an energy dissipation mechanism.
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Bohunská, Miroslava. « Studium interakcí tenzidové složky přípravku Septonex s vybranými proteiny ». Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449410.
Texte intégralRésumé :
The study of protein and surfactant interactions is of great significance in a number of applications, such as the cosmetic, food or pharmaceutical industries and many others. However, they require further study due to their compositional complexity and the limitations of current analytical approaches. In this thesis, the cationic surfactant septonex in combination with two differently charged proteins lysozyme and bovine serum albumin under different physiological conditions (temperature, surfactant concentration, environment and others) was selected to study the interactions. Characterization of protein-surfactant interactions is a very important but challenging task, therefore it is essential to use appropriate approaches to explore the nature of these interactions. In order to unify the information to provide rational models, calorimetric methods (DSC, ITC) and dynamic light scattering were used. Isothermal titration calorimetry monitors the evidence for the formation of the system of the mentioned substances and information on aggregation behavior, differential scanning calorimetry characterizes the thermal stability of proteins and dynamic light scattering made it possible to monitor changes in particle size. Both proteins have been proven to interact with positive septonex, even if the lysozyme molecule is also positively charged. However, significant differences were found between the two proteins. From the obtained results it is evident that the identical charge of the protein with the surfactant has an effect on the intensity of the measurement, although all measured interactions showed an endothermic character.
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Quainoo, Emmanuel W0bil. « METHOD DEVELOPMENT AND INVESTIGATION OF FLUORESCENT PHOSPHOINOSITIDE CELL SIGNALING PROPERTIES BY CAPILLARY ELECTROPHORESIS ». Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1271693846.
Texte intégral
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Malinenko, Alla. « Effet d’ion specifique sur l’auto-assemblage d’amphiphiles cationiques : des approches experimentale et informatique ». Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0065/document.
Texte intégralRésumé :
La présente étude est une approche holistique axée sur l'étude des effets spécifiques d'ions sur les propriétés d'auto-assemblage de tensioactifs cationiques gemini. Notre objectif principal étant l’étude de l'effet de divers contre-ions sur les caractéristiques d’auto-assemblage de tensioactifs cationiques en solution aqueuse. Afin d'obtenir une vision plus complète de l'effet des interactions ioniques et moléculaires à l’interface sur les propriétés globales, nous avons utilisé des approches différentes. Nous avons combiné une étude expérimentale portant sur les propriétés en solution (concentration micellaire critique, degré d'ionisation, nombre d'agrégation, etc.), avec des approches centrées sur l'étude des propriétés micellaires interfaciales en analysant les concentrations des contre-ions et de l'eau de façon expérimentale (piégeage chimique) et informatique (simulations de dynamique moléculaire). En outre, nous avons étudié l'impact de la nature des contre-ions sur la croissance des micelles géantes par rhéologie. En plus de l'examen des propriétés de tensio-actifs en solution, les effets spécifiques d'ions sur les structures cristallines des agents tensioactifs gémini ont été étudiés.Nous avons trouvé que les effets d'ions spécifiques qui déterminent le comportement des agrégats micellaires de gemini cationiques d'ammonium quaternaire dans des solutions aqueuses dépendent fortement de l'énergie libre d'hydratation des contre-ions, en d'autres termes, sur leur propriétés hydrophile /hydrophobe. Contrairement à la solution aqueuse, dans les cristaux, la taille de l'ion devient le facteur déterminant. La comparaison des résultats obtenus pour un même système en solution aqueuse et à l'état solide a montré l'importance des interactions ion-eau dans les effets spécifiques d'ions. Cependant, il faut noter que les propriétés du substrat (les gemini dans notre cas) doivent être prises en compte non moins soigneusement afin de prédire complétement les effets HofmeisterThe present study is a holistic approach focused on the investigation of ion specific effects on the self-assembly properties of cationic gemini surfactants. Our main focus was on the effect of various counterions on the self-organization features of cationic surfactants in aqueous solution. In order to obtain amore comprehensive understanding of the effect of interfacial ionic and molecular interactions on aggregate properties we used different approaches. We combined an experimental study focused on the bulk solution properties (critical micelle concentration, ionization degree, aggregation number, etc.), with approaches focused on investigating the interfacial micellar properties by analyzing the interfacial counterion and waterconcentrations, experimentally (chemical trapping) and computationally (molecular dynamic simulations). Moreover, the impact of counterion nature was investigated by studying the growth of wormlike micelles using rheology. Besides the examination of the surfactants properties in solution, the ion specific effects onthe crystalline structures of gemini surfactants were studied.We found that ion specific effects which determine the behavior of micellar aggregates of cationic quaternary ammonium gemini in aqueous solutions strongly depend on the free energy of hydration of the counterions, in others words, on their hydrophilic/hydrophobic properties. Contrarily to aqueous solution, in crystals, the size of the ion becomes the determining factor. Comparison of the results obtained for the same system in aqueous solution and in solid state showed the importance of ion-water interactions in ion specific effects. However, one should note that the properties of substrate (the gemini in our case) should be taken into account not less carefully in order to fully predict Hofmeister effects
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Bahri, Hamed. « Thermodynamique dans les milieux diphasés dispersés : cas des solutions micellaires et des microémulsions ». Paris 6, 1986. http://www.theses.fr/1986PA066280.
Texte intégralRésumé :
Déduction de relations théoriques générales liant dans les systèmes liquides diphasés, les grandeurs observables "globales" aux grandeurs "locales" dans les différentes phases. Exposé de définitions et de notions thermodynamiques. Etablissement de relations générales pour les grandeurs molaires partielles. Etudes du cas d'un système réel : bromures d'alkyltrimethylammonium en milieu eau-kcl, qui montre que les solutions micellaires en milieu salin concentré peuvent être considérées comme un système diphasé. Données sur le partage d'un soluté moléculaire aniline en milieu micellaire. Etudes des volumes molaires partiels des constituants d'une microémulsion, etc. . .
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Mader, Dorathea Felicitas. « Relation structure - propriétés de commutation dans les matériaux à transition de spin : effet de nanostructuration et de dilution du cation métallique ». Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10124/document.
Texte intégralRésumé :
Ces dernières années, de nombreux travaux de recherche ont été dédiés aux matériaux moléculaires à transition de spin à base de FeII, aussi bien du point de vue de la compréhension des phénomènes fondamentaux que de la mise en forme en vue d'applications. Ces matériaux présentent deux configurations électroniques inter-commutables sous l'effet d'une perturbation extérieure (bistabilité thermique et optique). Des interactions intra- et intermoléculaires fortes au sein du réseau cristallin peuvent conférer au matériau un comportement coopératif associé à des transitions de spin abruptes et un caractère hystérétique à l'origine d'un effet mémoire. La compréhension de l'origine de la coopérativité ainsi que sa maîtrise présentent à ce jour un intérêt certain. L'effet de la dilution métallique sur les propriétés de commutation photoinduites dans les composés FexZn1-x(btr)2(NCS)2.H2O est étudié par diffraction des rayons X sur monocristal. Un modèle microscopique expliquant les différents processus mis en jeu au cours de la transition (nucléation et séparation de phase) est proposé à partir d'une analyse structurale des données. Les effets de nanostructuration sont étudiés sur le polymère de coordination unidimensionnel [Fe(Htrz)2trz](BF4). Différents milieux inverses à base de tensioactif et d'organisation structurale variée (systèmes moléculaires organisés) ont été choisis pour une synthèse en environnement confiné (milieu micellaire inverse, phase cristal liquide hexagonale inverse (HII) et lamellaire (Lalpha)). Un lien entre la taille et la morphologie des particules, leur microstructure et leurs propriétés physico-chimiques est établi. Un intérêt particulier est porté à la dynamique de la réaction en milieu cristal liquideIn the last years, intensive research activity has been dedicated to iron(II)-based spin transition compounds, for a better understanding of the fundamental phenomena as within the scope of practical application. These molecular materials possess two electronic configurations, which are interchangeable by the application of an external perturbation (thermal and optic bistability). Strong electron-lattice coupling may lead to cooperative behaviour, consequently abrupt spin transitions and hysteretic behaviour at the origin of a memory effect. Understanding and controlling this property is of primary interest in fundamental and applied research. The influence of metal dilution on the photo-induced transitions in FexZn1-x(btr)2(NCS)2.H2O is investigated by X-Ray diffraction on single crystals. We suggest a microscopic model interpreting the dynamics of the phase transition (nucleation and growth mechanisms of spin-like domains) through a structural analysis of the diffraction data. The effects of nanostructuration on the physicochemical properties have been studied on the one-dimensional coordination polymer [Fe(Htrz)2trz](BF4). Different surfactant-based organized molecular systems with various structural organizations are chosen for the synthesis in confined environments: reverse micellar solutions as well as lamellar (Lalpha) and reverse hexagonal (HII) liquid crystal phases. A relationship between size and shape, microstructure and physicochemical properties is established with a specific attention to reaction dynamics in the liquid crystal phase
33
Vitart, Xavier. « Contribution a l'extraction liquide-liquide et a la separation de certains elements du groupe viii, notamment du ruthenium, par des systemes synergiques polyimines aromatiques-echangeurs cationiques micellaires ». Paris 6, 1987. http://www.theses.fr/1987PA066663.
Texte intégralRésumé :
Caracterisation et quantification des equilibres chimiques qui regissent un nouveau systeme d'extraction dont l'apport est de pouvoir operer a partir du milieux fortement acides avec des cinetiques d'extraction tres rapides. Des substitutions de coordinats sont prealablement operees en phase aqueuse. L'extraction elle-meme est realisee par des echangeurs cationiques formant des micelles inverses dans les diluants utilises. Cas de l'acide dinonylnaphtalenesulfonique
34
Berlot, Isabelle. « Synthèse, caractérisation et étude électrochimique de tensioactifs dérivés du pyrrole ». Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10087.
Texte intégralRésumé :
Ce memoire est consacre a la synthese, la caracterisation et l'etude electrochimique de nouveaux tensioactifs derives du pyrrole, analogues du dodecyltrimethylammonium et associes aux contre-ions br#-, no#-#3, tso#-, bf#-#4. La plupart forment des micelles en solution aqueuse. Une electrode selective du cation dodecyltrimethylammonium a ete utilisee pour determiner leurs concentrations micellaires critiques (cmc). Nous avons aussi montre que la voltammetrie cyclique permet dans certains cas de determiner la cmc en milieu electrolytique, en depit du caractere irreversible de l'oxydation de la sonde redox que constitue le pyrrole. On constate que l'introduction d'un motif pyrrole a l'extremite de la chaine hydrocarbonee (series a1 et a2) ne modifie pas la cmc de ces tensioactifs par rapport a leurs analogues sans pyrrole. Par contre si le pyrrole est situe sur la tete polaire (serie b1), leur cmc est plus basse. L'etude par rmn#1h a eclaire ces constatations, en precisant la localisation des divers groupements dans la micelle : le pyrrole se place dans le cur hydrophobe dans le cas des a1 et a2, alors qu'il se replie vers l'interieur de la micelle pres de la tete polaire pour les b1. Dans le cas particulier des tensioactifs associes a l'anion tosylate, nous avons constate que le tosylate penetre dans la micelle et s'intercale entre les groupes ammonium. L'etude electroanalytique a montre que ces composes s'adsorbent fortement sur carbone et que des films de polypyrrole peuvent croitre sur ces electrodes par electrooxydation de solutions micellaires. Ces films sont electroinactifs, mais d'epaisseurs significatives (20 a 1000 couches monomoleculaires). Les rendements de depots sont faibles (5 a 10%) dans le cas des a1 et a2, mais nettement plus importants (50%) dans le cas des b1. L'electropolymerisation de solutions micellaires des series a1 et a2 conduit majoritairement a la formation d'oligomeres solubles, de type polypyrrole suroxyde.
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Hahn, Jungseok. « Deposition of cationic polymer micelles on planar and patterned SiO₂ surfaces ». 2003. http://hdl.handle.net/2152/12109.
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Hahn, Jungseok Webber Stephen E. « Deposition of cationic polymer micelles on planar and patterned SiO₂ surfaces ». 2003. http://wwwlib.umi.com/cr/utexas/fullcit?p3119625.
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Soliman, Ghareb Mohamed. « Polysaccharide-based Polyion Complex Micelles as New Delivery Systems for Hydrophilic Cationic Drugs ». Thèse, 2009. http://hdl.handle.net/1866/3844.
Texte intégralRésumé :
Les micelles polyioniques ont émergé comme des systèmes prometteurs de
relargage de médicaments hydrophiles ioniques. Le but de cette étude était le
développement des micelles polyioniques à base de dextrane pour la relargage de
médicaments hydrophiles cationiques utilisant une nouvelle famille de copolymères bloc
carboxymethyldextran-poly(éthylène glycol) (CMD-PEG). Quatre copolymères CMD-PEG
ont été préparés dont deux copolymères identiques en termes de longueurs des blocs de
CMD et de PEG mais différent en termes de densité de charges du bloc CMD; et deux
autres copolymères dans lesquels les blocs chargés sont les mêmes mais dont les blocs de
PEG sont différents. Les propriétés d’encapsulation des micelles CMD-PEG ont été
évaluées avec différentes molécules cationiques: le diminazène (DIM), un médicament
cationique modèle, le chlorhydrate de minocycline (MH), un analogue semi-synthétique de
la tétracycline avec des propriétés neuro-protectives prometteuses et différents antibiotiques
aminoglycosidiques. La cytotoxicité des copolymères CMD-PEG a été évaluée sur
différentes lignées cellulaires en utilisant le test MTT et le test du Bleu Alamar. La
formation de micelles des copolymères de CMD-PEG a été caractérisée par différentes
techniques telles que la spectroscopie RMN 1H, la diffusion de la lumière dynamique
(DLS) et la titration calorimétrique isotherme (ITC). Le taux de relargage des médicaments
et l’activité pharmacologique des micelles contenant des médicaments ont aussi été évalués.
Les copolymères CMD-PEG n'ont induit aucune cytotoxicité dans les hépatocytes humains
et dans les cellules microgliales murines (N9) après 24 h incubation pour des
concentrations allant jusqu’à 15 mg/mL. Les interactions électrostatiques entre les
copolymères de CMD-PEG et les différentes drogues cationiques ont amorcé la formation
de micelles polyioniques avec un coeur composé du complexe CMD-médicaments
cationiques et une couronne composée de PEG. Les propriétés des micelles DIM/CMDPEG
ont été fortement dépendantes du degré de carboxyméthylation du bloc CMD. Les
micelles de CMD-PEG de degré de carboxyméthylation du bloc CMD ≥ 60 %, ont
incorporé jusqu'à 64 % en poids de DIM et ont résisté à la désintégration induite par les sels
et ceci jusqu'à 400 mM NaCl. Par contre, les micelles de CMD-PEG de degré de carboxyméthylation ~ 30% avaient une plus faible teneur en médicament (~ 40 % en
poids de DIM) et se désagrégeaient à des concentrations en sel inférieures (∼ 100 mM
NaCl). Le copolymère de CMD-PEG qui a montré les propriétés micellaires les plus
satisfaisantes a été sélectionné comme système de livraison potentiel de chlorhydrate de
minocycline (MH) et d’antibiotiques aminoglycosidiques. Les micelles CMD-PEG
encapsulantes de MH ou d’aminoglycosides ont une petite taille (< 200 nm de diamètre),
une forte capacité de chargement (≥ 50% en poids de médicaments) et une plus longue
période de relargage de médicament. Ces micelles furent stables en solution aqueuse
pendant un mois; après lyophilisation et en présence d'albumine sérique bovine. De plus,
les micelles ont protégé MH contre sa dégradation en solutions aqueuses. Les micelles
encapsulant les drogues ont maintenu les activités pharmacologiques de ces dernières. En
outre, les micelles MH réduisent l’inflammation induite par les lipopolysaccharides dans les
cellules microgliales murines (N9). Les micelles aminoglycosides ont été quant à elles
capable de tuer une culture bactérienne test. Toutefois les micelles aminoglycosides/CMDPEG
furent instables dans les conditions physiologiques. Les propriétés des micelles ont été
considérablement améliorées par des modifications hydrophobiques de CMD-PEG. Ainsi,
les micelles aminoglycosides/dodecyl-CMD-PEG ont montré une taille plus petite et une
meilleure stabilité aux conditions physiologiques. Les résultats obtenus dans le cadre de
cette étude montrent que CMD-PEG copolymères sont des systèmes prometteurs de
relargage de médicaments cationiques.Polyion complex (PIC) micelles have emerged as promising delivery systems of ionic hydrophilic drugs. It was the aim of this study to develop dextran-based PIC micelles for the delivery of hydrophilic cationic drugs using a new family of carboxymethyldextranblock- poly(ethylene glycol) (CMD-PEG) copolymers. Four CMD-PEG copolymers were prepared: (i) two copolymers identical in terms of the length of CMD and PEG blocks, but different in terms of the charge density of the CMD block; and (ii) two copolymers in which the charged block is the same, but the PEG block is of different molecular weight. The micellization of CMD-PEG copolymers and drug delivery aspects of the resulting micelles were evaluated using different cationic drugs: diminazene (DIM), a model cationic drug, minocycline hydrochloride (MH), a semisynthetic tetracycline antibiotic with promising neuroprotective properties and different aminoglycoside antibiotics. The cytotoxicity of CMD-PEG copolymers was evaluated in different cell lines using MTT and Alamar blue assays. CMD-PEG micelles encapsulating different drugs were characterized using different techniques, such as 1H NMR spectroscopy, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC). The pattern of drug release and pharmacological activity of micelles-encapsulated drugs were also evaluated. The CMD-PEG copolymers did not induce cytotoxicity in human hepatocytes and murine microglia (N9) in concentrations as high as 15 mg/mL after incubation for 24 h. Electrostatic interactions between CMD-PEG copolymers and different cationic drugs triggered the formation of PIC micelles with a CMD/drug core and a PEG corona. The properties of DIM/CMD-PEG micelles were strongly dependent on the degree of carboxymethylation of the CMD block. Micelles of CMD-PEG copolymers having degree of carboxymethylation ≥ 60%, incorporated up to 64 wt% DIM, resisted salt-induced disintegration in solutions up to 400 mM NaCl and sustained DIM release under physiological conditions (pH 7.4, 150 mM NaCl). In contrast, micelles of CMD-PEG of degree of carboxymethylation ~ 30% had lower drug content (~ 40 wt% DIM) and disintegrated at lower salt concentration (∼ 100 mM NaCl). The CMD-PEG copolymer that showed the most satisfactory micellar properties, in terms of high drug loading capacity, sustained drug release and micelles stability was selected as a potential delivery system of minocycline hydrochloride (MH) and different aminoglycosides. CMD-PEG micelles encapsulating either MH or aminoglycosides had small size (< 200 nm in diameter), high drug loading capacity (≥ 50 wt% drug) and sustained drug release. These micelles were stable in aqueous solution for up to one month, after freeze drying and in the presence of bovine serum albumin. Furthermore, the micelles protected MH against degradation in aqueous solutions. Micelles-encapsulated drugs maintained their pharmacological activity where MH micelles reduced lipopolysaccharides-induced inflammation in murine microglia (N9) cells. And aminoglycosides micelles were able to kill a test micro-organism (E. coli X-1 blue strain) in culture. Aminoglycosides/CMD-PEG micelles were unstable under physiological conditions. Micelle properties were greatly enhanced by hydrophobic modification of CMD-PEG. Thus, aminoglycosides/dodecyl-CMD-PEG micelles showed smaller size and better stability under physiological conditions. The results obtained in this study show that CMD-PEG copolymers are promising delivery systems for cationic hydrophilic drugs.
38
Feng, Tzu-Hua, et 馮子驊. « Synthesis and Characterization of Star-Shaped Cationic Copolymer Hybrid Micelles as a Gene Vector ». Thesis, 2012. http://ndltd.ncl.edu.tw/handle/52853289244065649927.
Texte intégralRésumé :
碩士高雄醫學大學
醫藥暨應用化學研究所
100
In this study, amphiphilic star-shaped cationic copolymers were synthesized of hydrophobic monomer and hydrophilic cationic monomer. The synthesized polymer was determined by 1H-NMR spectroscopy and gel permeation chromatography (GPC). The synthesized star-shaped cationic copolymer micelles and hybrid micelles contained PEG are formed by oil-in-water solvent evaporation method. The polyplex binding ability, transfection efficiency and cytotoxicity of micelles are all compared by gel electrophoresis performance, luciferase assay and MTT assay.
39
Fang, I.-Ju, et 方怡茹. « Capillary Electrophoretic Studies on Influence of Interactions of Cationic Solutes with Sodium Dodecyl Sulfate on the Formation of Micelles and its Critical Micelle Concentration ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/78468409324891983767.
Texte intégralRésumé :
碩士國立臺灣大學
化學研究所
92
Abstract The migration behavior of cationic solutes and influences of the interactions of cationic solutes with sodium dodecyl sulfate (SDS) on the formation of micelles and its critical micelle concentration (CMC) were investigated by capillary electrophoresis at neutral/acidic pH. Catecholamines and structurally related compounds, including epinephrine, norepinephrine, dopamine, norephedrine, and tyramine, which involve different extents of hydrophobic, ionic and hydrogen bonding interactions with SDS surfactant, are selected as cationic solutes. The dependence of the effective electrophoretic mobility of cationic solutes on the concentration of SDS monomers in the premicellar region provides direct evidence of the formation of ion-pairs between cationic solutes and SDS monomers. Three different approaches, based on the variations of either the effective electrophoretic mobility or the retention factor as a function of SDS concentration in the premicellar and micellar regions, and the linear relationship between the retention factor and the product of a distribution coefficient and the phase ratio, were considered to determine the CMC value of SDS micelles. The suitability of the methods used for the determination of the CMC of SDS with these cationic solutes was discussed. Depending on the structures of cationic solutes and electrophoretic conditions, the CMC value of SDS determined varies in a wide concentration range. The results indicate that, in addition to hydrophobic interaction, both ionic and hydrogen bonding interactions have pronounced effects on the formation of SDS micelles. Ionic interaction between cationic solutes and SDS surfactant stabilizes the SDS micelles, whereas hydrogen bonding interactions weakens the solubilization of the attractive ionic interaction. The elevation of the CMC of SDS depends heavily on hydrogen bonding interactions between cationic solutes and SDS surfactant. Thus the CMC value of SDS is remarkably elevated with catecholamines, such as epinephrine and norepinephrine, as compared with norephedrine. In addition, the effect of methanol content in the sample solution of these cationic solutes on the CMC of SDS was also examined. The binding constant of cationic solutes with SDS monomers and those of cationic solutes to SDS micelles are evaluated. The influence of ��-cyclodextrin (��-CD) on the critical micelle concentration (CMC) of sodium dodecyl sulfate (SDS) was investigated by capillary electrophoresis using cationic solutes as probe molecules at pH 7.0. The variations of the electrophoretic mobility of probe molecules as a function of surfactant concentration in both premicellar and micellar regions in the absence and presence of ��-CD was analyzed. The results indicate that, as a consequence of a strong inclusion complexation between ��-CD and SDS, the encapsulation of ��-CD with probe molecules is greatly diminished, or even vanished, in the presence of SDS. The complexes formed between ��-CD and SDS monomers exist predominantly in the form of a 1:1 stoichiometry, while complexes with a 2:1 stoichiometry reported previously in the literature as a minor component is indicative at a concentration of ��-CD exceeding about 7mM. The elevation of the CMC value of SDS depends on the concentration of ��-CD in the buffer electrolyte . The binding constants of probe molecules to ��-CD, to surfactant molecules, and to the complexes formed between ��-CD and SDS are reported.
40
Rajashekara, Haramagatti Chandrashekara. « Structure, Dynamics and Phase Behaviors of Cationic Micellar Solutions : ». Doctoral thesis, 2006. http://hdl.handle.net/11858/00-1735-0000-0006-B612-A.
Texte intégral
41
Pekařová, Kateřina. « Kationické povrchově aktivní látky a hodnocení jejich vlastností ». Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-388732.
Texte intégralRésumé :
Charles University Faculty of Pharmacy in Hradec Králové Department of Biophysics and Physical Chemistry Consultant: PharmDr. Jan Marek, Ph.D. Supervisor: doc. PharmDr. Veronika Nováková, Ph.D. Student: Kateřina Pekařová Title of Thesis: Cationic surface active compounds and evaluation of its properties Quaternary ammonium salts are used as surfactants in many branches of the food, pharmaceutical and chemical industries. The basic properties of these substances were studied in the thesis. The critical micellar concentration of the homologous series of five substances was determined using the conductometric method. The theory of declining critical micellar concentration with the increasing length of the side alkyl chain has been verified. The hydrolytic activity of two commonly used cationic surfactants benzalconium chloride and benzoxonium chloride for the decomposition of the organophosphorus pesticide fenitrothion was tested. For these two substances, the effect of pH and temperature changes was evaluated. The influence of tenside concentration was also monitored. Benzoxonium chloride at 50 řC and pH 11was found as the most effective hydrolytic catalyst for the decomposition of the organophosphorus pesticide fenitrothione.
42
Chen, Wei-Ju, et 陳薇如. « Analysis of Cellular Uptake and Distribution of Cationic Micelles Complexed with Oligonucleotides and Transmenbrane Enhancers in Mammalian Cells ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/44901608525423901619.
Texte intégralRésumé :
碩士國立臺灣大學
生物化學暨分子生物學研究所
97
Gene therapy offers the promise of treating disease. In general, two target sites inside cells are cytoplasm or nucleus in case of delivering therapeutic molecules such as DNA, RNA, peptides and proteins by nanoparticles. There are complicated problems in targeting these molecules. It was difficult for the large charge molecules such as DNA to pass across plasma and nucleic membrane on their own. For these reasons, I developed a non-viral micelle delivery system using the surface-modified lipid nanoparticles. It was composed one positive charge lipid, called GEC-cholesterol with cholesterol, PEG lipid and biotinylated lipid. The surface-exposed biotin moiety could interact with the bifunctioned fusion protein containing streptavidin. Adding magnetic field sequentially could force the lipid nanoparticles complexed with oligonucleotides into the cytosol; meanwhile NLS associated with intracellular binding proteins then transported into the nucleus of cancer cells and rat bone marrow stem cells. The results indicated that manipulating the magnetic force could efficiently enhance nanoparrticles transported into cells. Besides, NLS-Streptavidin fusion proteins themselves couldn’t enter into the cytoplasm. But magnetic nanoparticles inside the lipid micelles were entered significantly into the nucleus with the assistant of magnetic fields. Thus, magnetic field might be benefit for targeting nanoparticles with cargos into nucleus.
43
Wazen, Nada. « Micelles polyioniques ternaires pour la libération intracellulaire d’oligonucleotides ». Thèse, 2010. http://hdl.handle.net/1866/5100.
Texte intégralRésumé :
Les oligonucléotides (ONs) antisens présentent un fort potentiel en tant qu’agents thérapeutiques. Toutefois, leurs propriétés physicochimiques limitent leur utilisation en thérapie génique. Pour pallier aux divers obstacles, des systèmes de vectorisation, tels que les micelles polyioniques (PICMs), ont été développés. Grâce à leur structure unique, les micelles protégent l’ON contre une dégradation prématurée et le couplage d’un ligand à leur surface augmente leur spécificité et leur internalisation. Dans d’autres systèmes, un polymère adjuvant aux propriétés pH-sensibles peut être ajouté pour faciliter la sortie de l’endosome et augmenter l’efficacité de l’ON.
L’objectif général de ce mémoire était de mettre au point des PICMs ternaires ciblées pour l’administration d’ONs. Ces micelles assureraient à la fois l’internalisation cellulaire de leur cargaison en interagissant avec des récepteurs cellulaires et sa fuite de l’endosome grâce à un mécanisme de déstabilisation de la membrane endosomale. Pour cela, des PICMs composées d’un copolymère cationique de type poly(éthylène glycol)-bloc-poly(méthacrylate d’(alkylamino)éthyle) et d’un copolymère d’acide méthacrylique ont été préparées. Les propriétés physicochimiques de ces vecteurs ont démontré qu’ils permettaient une condensation efficace de l’acide nucléique et ce, indépendamment de la nature du polymère cationique et de l’acide nucléique. Finalement, une approche de couplage par pont disulfure a été développée afin de greffer au copolymère un fragment d’anticorps dirigé contre les récepteurs de la transferrine.
En conclusion, ces travaux démontrent la versatilité et le potentiel des PICMs ternaires en tant que vecteurs d’acide nucléique, et proposent une méthodologie de couplage d’un ligand afin de formuler des PICMs ciblées.Antisens oligonucleotides (ONs) present great potential as therapeutic agents. However, their physicochemical properties hinder their use in gene therapy. Targeting systems, such as polyion complex micelles (PICMs), have been proposed to circumvent the main hurdles related to ON delivery. Their unique core/shell structure can protect the ON against premature degradation and the coupling of a ligand on their surface can increase their specificity and internalization. In other systems, a polymer with pH-sensitive properties can be added to facilitate the release of the ON from the endosome and increase its efficiency. The present work was aimed at optimizing ternary PICMs targeted for the delivery of antisens ON. Such systems would provide both cellular internalization of cargo by interaction with receptors on the surface of cell membranes and escape from the endosome through a mechanism of destabilization of the endosomal membrane. PICMs composed of cationic copolymers of poly(ethylene glycol)-bloc-poly((alkylamino)ethyl methacrylate) with a methacrylic acid copolymer adjuvant were prepared. Their physicochemical properties suggest that efficient complexation of nucleic acids was obtained, regardless of the nature of the cationic polymer and the nature of the nucleic acid. Finally, a synthetic approach was developed for the conjugation of an antibody fragment directed against the transferrin receptor via a labile disulfide bond at the end of the cationic copolymer. In conclusion, the work presented herein displays the versatility and potential of ternary PICMs as vehicles for the delivery of ONs and also provides a method for the conjugation of a ligand to generate targeted ternary PICMs.
44
Bhat, Shreedhar. « Soft Materials Derived From Bile Acid Analogues ». Thesis, 2007. http://hdl.handle.net/2005/483.
Texte intégralRésumé :
Chapter 1. Introduction
This chapter is an overview on the literature of self-association of small organic molecules. The chapter is presented in four parts. First, an introduction to aggregation of small molecules is given with the emphasis on micelles and gels(Parts 1 and 2) In part 3, a short overview is given on bile acid based aggregates and their applications. Lastly, the content of the thesis is outlined.
Chapter 2. Solution properties of novel cationic bil salts: A structure-aggregation property study
Scheme 1: Structures of Cationic bile salts(Refer PDF File)
Bile Salts are biosurfactants and they are known to form micelles in aqueous medium. We studied the micellar properties of cationic bile salts(Scheme 1) and compared with their natural (anionic) counterparts. A serendipitous discovery of the gelation of a cationic bile salt(4) led us to investigate the aggregation properties of this new class of cationic hydrogelators. This chapter highlights the recent efforts on the study of side chain structure-aggregation property relationship of cationic bile salts. Bile acid analogues with a quaternary ammonium group(Scheme 1, compounds 2, 3, 4, 6, 8 and 12) on the side chain were found to efficiently gel aqueous salt solutions. Some of the cationic bile salts gelled water alone and many of them gelled aqueous salt solutions even in the presence of organic co-solvents(≤ 20%) such as ethanol, methanol, DMSO and DMF. A strong counter ion dependent gelation was observed. These gels showed interconnected fibrous networks. Unlike natural anionic bile salt gels(reported for NaDC, NaLC), the cationicgels reported here are pH independent. Cationic gels derived from DCA showed more solid-like rheological response compared to natural NaDC gels studied earlier by Tato et al. A strong structure(side-chain) andcounter-ion dependent flow of the cationic bile salt gels was seen.
Chapter 3. Applications of cationic bile salts and their aggregates
Cationic bile salts are useful in many ways. We have studied some of the applications of cationic bile salts(discussed in chapter 2) and their aggregates in this chapter. The chapter is presented in three parts.
Part 1. Interaction of Cationic bile salts and DNA
The bile acid amphiphilicity is believed to help the DNA binding process of polyamines. This has prompted us to study the DNA-bile salt binding interaction of bile salts. The binding of cationic bile salts has been expressed in terms of C50 values, which were determined from the plot of fluorescence of ethidium bromide bound DNA vs. bile salt concentration(Fig 1) The C50 values for cationic bile salts were estimated to be about 1.2 mM.
Fig1: A plot of fluorescene of ethidium bromide bound DNA against bile salt concentration (Refer PDF File)
Part 2. Cholesterol solubilization and crystallization studies in aqueous bile salt solutions.
Dihydroxy bile salt micelles are well known for cholesterol dissolution(e.g. UDCA and CDCA). We studied the dissolution of cholesterol in the cationic bile salt micelles(of 21-25) and the results are discussed in this part.
Scheme 2: Cationic bile salt chlorides studied for cholesterol dissolution (Refer PDF File)
A powder dissolution method was used to study the solubility of anhydrous cholesterol in cationic bile salt solution. These cationic bile salt micelles can dissolve cholesterol to the same extent as the taurine conjugates of bile acids, but lesser than the natural anionic bile salts(Fig.2) Addition of PC(Phosphatidylcholine) to cationic bile salt micelles enhanced the micellar cholesterol solubilization.
Fig 2:Cholesterol dissolution in cationic bile salt solutions(Refer PDF File)
The crystal nucleation time of cholesterol did not change significantly by adding 5-30 mM of the cationic bile salts. The bile salt analogues did, however, attenuate cholesterol crystallization to a similar extent at all concentrations studied. All these effects wer comparable to those fo cholic acid.
Part 3. Hydrogels as a reaction vessel for photodimerization
Bile salt micelles have been shown to control the product selectivity in photochemical reactions. The dynamic nature of the bile salt micelles results in differential effects on reaction selectivity. The photodimerization of acenaphthylene(sheme 3) was studied in micellar and hydrogel medium(e.g. NaDC, 22, 28, etc.) The ratio of anti- to synphotodimer was found to be greater in gel bound state than in solution. Substitution on the CAN ring did not show larger variation on the product distribution from solution gel.
Scheme 3: Photodimerization of acenaphthylene(Refer PDF File)
Chapter 4. Bile acid derived sulfur analogues in designing novel materials.
Part 1. A simple approach towards nanoparticle-gel hybrid material.
Scheme 4: Scheme for the synthesis of thiols derived from bile acids (Refer PDF File)
Our interest in bile acid based gelator molecules led us to explore the synthesis and properties of bile analogues with the side chain carboxylic acid replaced by a thiol(Scheme 4) to stabilize metal NPs. We reasoned that the specific self-aggregation modes of facially amphiphilic bile units would enable a metal NP capped by such a thiol to “lock” onto a gel fiber derived from a structurally related gelator molecule. AuNPs stabilized by 38-40 were obtained by the NaBH4 reduction of homogeneous methanolic solutions of the thiol and gold salt. These steroid capped nanoparticles were found to stay dispersed in a gel of 28, thus providing a simple approach to obtain gel-nanoparticle hybrid.
A photograph of the hybrid material and their morphology are shown in Fig 3.(Refer PDF File)
Chart 1: Structure of the gelator used for designing a hybrid material(Refer PDF File)
Part 2. Gelation of aromatic solvents using sulfur analogues of bile acid
A few of the sulfur derivatives were serendipitously fouond to gel organic solvents (Fig 4). Thiol 38 formed stable gels at room temperatures while the disulphide 36 formed stable gels below 5º C. The aggregation properties, morphology, and the melting profiles of gels of disulfides and thiols derived from bile acids have been highlighted in this part.
Fig 4: A photograph of the gels derived from 38(Refer PDF File) (For Figures and Molecular Formula Pl refer the Original Thesis)
45
FALSINI, SARA. « Development of new therapeutic strategies for hERG targeting in leukemia cells ». Doctoral thesis, 2014. http://hdl.handle.net/2158/850296.
Texte intégralRésumé :
Questa tesi si inserisce in un filone di ricerca in cui viene studiato il coinvolgimento di hERG, canale del potassio voltaggio dipendente nella patogenesi tumorale. In particolare è noto il suo ruolo nella chemioresistenza delle leucemie dipendente dal microambiente midollare e questo ha suggerito hERG come possibile bersaglio per la terapia antileucemica. In questo lavoro di tesi sono stati sviluppati due possibili approcci uno farmacologico e l’altro molecolare al fine di inibire l’attività di questo canale.
Nel primo caso abbiamo scelto la claritromicina, un antibiotico macrolide già in commercio la cui attività inibitoria nei confronti di hERG è già stata documentata studiandone l’ effetto in combinazione o in assenza di citarabina (chemoterapico) su una linea cellulare di leucemia promielocitica acuta (HL60). Questi esperimenti sono stati effettuati su cellule in sospensione oppure in co-coltura con cellule stromali mesenchimali. Dagli esperimenti in vitro è stato dimostrato che la combinazione dei due farmaci riduce l’attività chemoprotettiva indotta dal microambiente midollare (CI=0.657). I risultati incoraggianti ci hanno permesso di passare a studiare l’effetto dei due farmaci su topi SCID (Severe Combined Immunodeficency Disease) inoculati con HL60 marcate con la luciferasi. Inizialmente è stata dimostrata la capacità della claritromicina di ridurre lo sviluppo tumorale e la sua invasività. Successivamente l’effetto combinato con citarabina garantisce una maggior sopravvivenza rispetto ai controlli, con almeno 20 giorni di differenza.
Per quanto riguarda l’approccio molecolare abbiamo valutato la possibilità di silenziare hERG mettendo a punto nuovi sistemi per veicolare il siRNA corrispondente. Per questo scopo sono stati scelti quattro tensioattivi cationici: 12-3-12, 12-6-12, 12-12-12 e SH14 le cui micelle possono essere impiegate come vettori per la terapia genica. E’ stata studiata la cinetica di formazione dei complessi tra micelle e siRNA per conoscerne la struttura e quindi la stabilità, parametri chiave per l’efficienza di transfezione. La caratterizzazione chimico-fisica è stata seguita mediante SAXS presso European Synchrotron Radiation Facility (ESRF) di Grenoble. Questa tecnica sfrutta l’utilizzo di un fascio di raggi X che, una volta diffuso dalla nuvola elettronica degli atomi specialmente da quelli con numero atomico più elevato che compongono i complessi, fornisce un segnale dipendente dalla struttura. E’ stato possibile misurare la variazione di forma e di dimensioni durante il processo di formazione dei complessi. Le due soluzioni di siRNA e di micelle sono state caricate separatamente mediante un dispositivo di miscelamento controllato via computer (stopped-flow) e accoppiato alla tecnica SAXS. Si è osservato che il processo di formazione dei complessi è estremamente rapido e avviene subito dopo il mixing, in tempi inferiori a 0.05s.
All’interno dei nanoaggregati le due componenti (siRNA e micelle) si alternano con distanze ripetitive di 3-4nm e con l’aumentare del tempo il numero di unità che li compongono aumenta (fino a 4-8 unità a seconda del tipo di tensioattivo). Gli aggregati contenenti SH14 sono meno ordinati rispetto agli altri. Alla fine della registrazione (circa 15 minuti dopo il mixing) il raggio di girazione dei complessi è compreso tra 7 e 27nm; queste dimensioni sono compatibili con un’elevata efficienza di transfezione.
46
Dufresne, Marie-Hélène. « Mise au point de micelles polyioniques pour l'administration de biomacromolécules thérapeutiques : synthèse de polymères et études physicochimiques ». Thèse, 2008. http://hdl.handle.net/1866/6649.
Texte intégral
47
CASHIN, PATRICK. « Sulfonamide Partitioning to Aqueous Cationic Micellar Systems ». Thesis, 2011. http://hdl.handle.net/1974/6291.
Texte intégralRésumé :
Advances in analytical chemistry have resulted in a growing body of literature showing measurable concentrations of pharmaceuticals in both drinking and wastewater. Removal of such chemicals is typically inefficient and often poorly characterized. To characterize one such method of removal (micellar enhanced ultrafiltration, (MEUF)), interactions of a cetyl trimethylammonium bromide (CTABr) surfactant and sulfonamide antibiotics were examined by NMR and semi-equilibrium dialysis (SED).
The locus and orientation of binding in a micelle was established for seven sulfonamides by 1H NMR, and it was found that hydrophilic sulfonamides showed weak coordination with the micelle, whereas hydrophobic sulfonamides penetrated into the micellar interior with coordination of the SO2NH group to the charged surface layer.
Binding constants were determined by 1H NMR and showed apparent order of magnitude differences between nuclei. Several compounds were unable to be characterized in this manner due to low change in chemical shift with addition of CTABr. SED was performed as an alternative method to determine binding constants. Values determined in this manner were higher than those determined by 1H NMR. Binding constants were converted into changes in Gibbs free energy and used to evaluate and, where necessary, modify the orientation and locus proposed by 1H NMR.
Attempts are made to correlate binding constants with octanol-water partition coefficients to determine if a free energy relationship can be derived. Characterization of these systems may allow for a predictive methodology to determine the MEUF removal efficiencies of new sulfonamide and surfactant combinations. It is also hoped that this work may be generalized to predict MEUF efficiency for a wide range of contaminants that might be found in wastewater.Thesis (Master, Chemistry) -- Queen's University, 2011-01-31 09:46:28.248
48
Wang, MeiHui, et 王美惠. « Regeneration Cationic Surfactant in Micellar-Enhanced Ultrafiltration System ». Thesis, 2000. http://ndltd.ncl.edu.tw/handle/75176096972777344506.
Texte intégralRésumé :
碩士國立屏東科技大學
環境工程與科學系
88
Removal of dissolved low-molecular-weight organics and multivalent metal ions from wastewater is not efficient by conventional separation techniques such as distillation and adsorption process. Micellar-enhanced ultrafiltration (MEUF) system has been successfully applied as a technique for removing dissolved contaminants from aqueous streams and for surfactant soil washing process. Regeneration of surfactant from this separation processes are economically attractive by reducing raw material costs. Therefore, it is important to recover surfactant from MEUF process. The objective of this study is to understand the binding behaviors between surfactant and contaminants and to study how to utilize a simple physichemical method to separate surfactant from pollutants (chromate or phenol). Then the process feasibility of the combination of both membrane separation system and surfactant regeneration system were evaluated by reusing the surfactant, metal, organics, and product water. Precipitation method was utilized to recover cationic surfactant from pollutants. Two processes were used in this study. Firstly, salts such as calcium chloride, iron chloride, barium chloride was added to react with chromate and form insoluble precipitates. Secondly ions which had opposite charge (counter ion) were added to the surfactant because of the low solubility of surfactant-iodine complex. Redissolution of surfactant back into water is an important step before it can be recycled and reused. One way to accomplish this goal is to introduce co-ion(ions with the same charge as the counter ion) which tends to precipitate with the counter ion preferentially to the surfactant ion. This research included two sections：the first section is to construct a batch experiments to determine the type and optimal ratio of precipitation agents, counter ion and co-ion. The second section is to combine the membrane separation system with surfactant recovery system. The results showed that：（1）the molar ratio of precipitation agents and chromate greater than 2, the regeneration ratio of surfactant was greater than 70% ；（2）the molar ratio of counter ion and chromate greater than 1.25, the molar ratio of co-ion and CPC greater than 1.5, the regeneration ratio of surfactant was around 50% ；（3）the molar ratio of counter ion and phenol greater than 1, co-ion and CPC molar ratio greater than 0.5, the regeneration ratio of surfactant was around 50% ；（4）regenerated surfactant still had the capacity to adsorb contaminants.
49
陳惠美. « Studies of the Preparation and Characterization of Cationic Polymeric-Micelle ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/83ecst.
Texte intégral
50
Chung, Zen-Hung, et 鍾仁宏. « Preparation of Cationic PLGA Micelle Conjugated with Polyurethane Dendrimer for Delivery of DNA ». Thesis, 2015. http://ndltd.ncl.edu.tw/handle/xqg826.
Texte intégralRésumé :
碩士嘉南藥理大學
生物科技系
103
Gene therapies using DNA and siRNA have been widely investigated in fundamental research. There are many methods to increase the transfection and gene expression including viral and non-viral vectors. Due to many drawbacks of viral vectors, non-viral carriers became another choice for gene therapy. Generally, the polymeric micelles were usually composed of amphiphilic block copolymers. The research was designed to use polyurethane dendrimers(PUAD) as a hydrophilic periphery. Because of the dendrimers with cationic characteristic, therefore, we conduct some test on the polymeric micelles to make sure that their potential to be a transfection vector. Biodegradable material poly(D,L-lactide-co-glycolide)(PLGA) was used as a inter hydrophobic core and reduced the toxicity of cationic PUAD. In this study, we used different generations of PUAD (G 2.0, 3.0) and PLGA to form amphiphilic block copolymers by dehydration reaction and their chemical structures were confirmed using FT-IR and NMR. The following tests were to evaluate the characteristics of PLGA-PUAD micelles: DLS to analyze its particle size and zeta-potential, electrophoresis, cytotoxicity, and transfection efficiency. It was found that the PUAD-PLGA can become a potential non-viral gene vectors based on the above results.