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Start Over Author "Mancini, Giovanna" Journal langmuir
27 results on '"Mancini, Giovanna"'

3. Generation of a Chiral Giant Micelle

Author

Ito, Thiago H., primary, Salles, Airton G., additional, Priebe, Jacks P., additional, Miranda, Paulo C. M. L., additional, Morgon, Nelson H., additional, Danino, Dganit, additional, Mancini, Giovanna, additional, and Sabadini, Edvaldo, additional

Published
2016
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26. Role of the Spacer Stereochemistry on the Aggregation Properties of Cationic Gemini Surfactants

Author

Bello, Cristiano, Bombelli, Cecilia, Borocci, Stefano, di Profio, Pietro, and Mancini, Giovanna

Abstract

The preparation and characterization of three stereoisomeric cationic gemini surfactants, 2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonio)butane dibromide, are described. The aggregation properties have been studied by fluorescence, electrical conductivity, and quasi-elastic light scattering. A conformational study of the surfactant headgroups has been performed by molecular mechanics calculations to investigate the effect of the stereogenic centers on the surfactant molecular shape and therefore on the different organizations of the monomers in the aggregates. Results show that the stereochemistry of the spacer strongly influences the aggregation behavior of the diasteromeric gemini in water.

Published
2006
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27. Impact of Reductive Cleavage of an Intramolecular Disulfide Bond Containing Cationic Gemini Surfactant in Monolayers and Bilayers

Author

Matti J. Säily, V., J. Ryhänen, Samppa, Lankinen, Hilkka, Luciani, Paola, Mancini, Giovanna, J. Parry, Mikko, and K. J. Kinnunen, Paavo

Abstract

The properties of a novel disulfide-bond-containing gemini surfactant bis[N,N-dimethyl-N-hexadecyl-N-(2-mercaptoethyl)ammonium bromide] disulfide (DSP) were studied using a Langmuir balance, supported monolayers, differential scanning calorimetry, giant vesicles, and LUVs. In 150 mM NaCl the cmc for DSP was 7.5 μM whereas that of the monomer N,N-dimethyl-N-hexadecyl-N-(2-mercaptoethyl)ammonium bromide (MSP) was 12.1 μM. Both surfactants exhibited single endotherms upon DSC, with peak temperatures Tm at 21.7 and 20.1 °C for DSP and MSP, respectively. The endotherm for MSP was significantly broader indicating less cooperative melting. Both in monolayers and in vesicles reductive cleavage of the disulfide bond of DSP could be obtained by glutathione (GSH). For Langmuir films of DSP the addition of GSH into the subphase led to a decrease in surface pressure π as well as surface dipole potential Ψ. Although the cleavage by GSH was significantly slower in the presence of a charge saturating concentration of DNA, it did not prevent the reaction. The resulting monomers detached from supported monolayers, leading to loss of affinity of the surface for DNA. Disruption of giant vesicles containing DSP within approximately 30 s following a local injection of GSH was observed, revealing membrane destabilization.

Published
2006
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