DODAB and DODAC bilayer-like aggregates in the micromolar surfactant concentration domain
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Data
2009-05-01
Autores
Feitosa, Eloi [UNESP]
Rosa Alves, Fernanda
Castanheira, Elisabete M. S.
Oliveira, M. Elisabete C. D. Real
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Editor
Springer
Resumo
In the millimolar concentration domain (typically 1 mM), dioctadecyldimethylammonium bromide and chloride (DODAX, X representing Br(-) or Cl(-) counterions) molecules assemble in water as large unilamellar vesicles. Differential-scanning calorimetry (DSC) is a suitable technique to obtain the melting temperature (T (m)) characteristic of surfactant bilayers, while fluorescence spectroscopy detects formation of surfactant aggregates, like bilayers. These two techniques were combined to investigate the assembly of DODAX molecules at micromolar concentrations, from 10 to 100 mu M. At 1 mM surfactant, T (m) a parts per thousand aEuro parts per thousand 45 A degrees C and 49 A degrees C, respectively, for DODAB and DODAC. DSC and fluorescence of Nile Red were used to show the formation of DODAX aggregates, at the surfactant concentration as low as 10 mu M, whose T (m) decreases monotonically with increasing DODAX concentration to attain the value for the ordinary vesicles. The data indicate that these aggregates are organized as bilayer-like structures.
Descrição
Palavras-chave
DODAB, DODAC, DSC, Nile Red, Cationic vesicle, Melting temperature, Steady-state fluorescence
Como citar
Colloid and Polymer Science. New York: Springer, v. 287, n. 5, p. 591-599, 2009.