Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/5579

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dc.contributor.authorFeitosa, Eloi-
dc.contributor.authorAlves, Fernanda Rosa-
dc.contributor.authorNiemiec, Anna-
dc.contributor.authorOliveira, M. Elisabete-
dc.contributor.authorCastanheira, Elisabete M. S.-
dc.contributor.authorBaptista, Adelina L. F.-
dc.date.accessioned2006-09-22T10:17:44Z-
dc.date.available2006-09-22T10:17:44Z-
dc.date.issued2006-03-
dc.identifier.citation"Langmuir". ISSN 0743-7463. 22:8 (Apr. 2006) 3579-3585.eng
dc.identifier.issn0743-7463eng
dc.identifier.urihttp://hdl.handle.net/1822/5579-
dc.description.abstractThe thermotropic phase behavior of cationic liposomes in mixtures of two of the most investigated liposomeforming double-chain lipids, dioctadecyldimethylammonium bromide (DODAB) and didodecyldimethylammonium bromide (DDAB), was investigated by differential scanning calorimetry (DSC), turbidity, and Nile Red fluorescence. The dispersions were investigated at 1.0 mM total surfactant concentration and varying DODAB and DDAB concentrations. The gel to liquid-crystalline phase transition temperatures (Tm) of neat DDAB and DODAB in aqueous dispersions are around 16 and 43 °C, respectively, and we aim to investigate the Tm behavior for mixtures of these cationic lipids. Overall,DDABreduces the Tm of DODAB, the transition temperature depending on the DDAB content, but the Tm of DDAB is roughly independent of the DODAB concentration. Both DSC and fluorescence measurements show that, within the mixture, at room temperature (ca. 22 °C), the DDAB-rich liposomes are in the liquid-crystalline state, whereas the DODAB-rich liposomes are in the gel state. DSC results point to a higher affinity of DDAB for DODAB liposomes than the reverse, resulting in two populations of mixed DDAB/DODAB liposomes with distinctive phase behavior. Fluorescence measurements also show that the presence of a small amount of DODAB in DDAB-rich liposomes causes a pronounced effect in Nile Red emission, due to the increase in liposome size, as inferred from turbidity results.eng
dc.description.sponsorshipFundação para a Ciência e Tecnologia (FCT)por
dc.language.isoengeng
dc.publisherAmerican Chemical Societyeng
dc.rightsrestrictedAccesseng
dc.subjectCationic liposomeseng
dc.subjectDODABeng
dc.subjectDDABeng
dc.subjectDSCeng
dc.subjectNile Redeng
dc.titleCationic liposomes in mixed didodecyldimethylammonium bromide and dioctadecyldimethylammonium bromide aqueous dispersions studied by differential scanning calorimetry, nile red fluorescence, and turbidityeng
dc.typearticlepor
dc.peerreviewedyeseng
dc.relation.publisherversionThe original publication is available at www.pubs.acs.orgeng
sdum.number8eng
sdum.pagination3579 - 3585eng
sdum.publicationstatuspublishedeng
sdum.volume22eng
oaire.citationStartPage3579por
oaire.citationEndPage3585por
oaire.citationIssue8por
oaire.citationVolume22por
dc.identifier.doi10.1021/la053238fpor
dc.identifier.pmid16584229por
dc.subject.wosScience & Technologypor
sdum.journalLangmuirpor
Appears in Collections:CDF - FAMO - Artigos/Papers (with refereeing)

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