The effect of cationic gemini surfactants upon lipid membranes. An experimental and molecular dynamics simulation study

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Joao A S Almeida (Author) Other; Eduardo F Marques (Author) FCUP; Amalia S Jurado (Author) Other; Alberto A C C Pais (Author) Other

Journal

Title: Physical Chemistry Chemical Physics

Vol. 12 No. 36

Pages: 14462-14476

ISSN: 1463-9076

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 34 Citations

Scopus - 40 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

CORDIS: Physical sciences > Chemistry > Analytical chemistry > Spectrochemistry ; Physical sciences > Chemistry > Physical chemistry > Surface chemistry ; Physical sciences > Chemistry > Computational chemistry ; Physical sciences > Chemistry > Applied chemistry

Other information

Authenticus ID: P-003-1PD

DOI: 10.1039/c0cp00950d

Abstract (EN): Gemini surfactants possess interesting interfacial and aggregation properties that have prompted comprehensive studies and successful applications in a wide variety of fields. However, a systematic study on the effect of gemini tail and spacer length upon the organization of lipid membranes has not been presented so far. In this study, we analyze the action of dicationic alkylammonium bromide gemini surfactants on DPPC liposomes, the latter employed as a model of lipid membranes. Differential scanning calorimetry results indicate that the surfactants presenting shorter tails (12 carbons) induce a decrease in the overall order of the bilayer, while those with longer tails (16 and 18 carbons) lead to the formation of more ordered structures. The respective influence on the degree of lipid order transverse to the bilayer was additionally studied resorting to a detailed fluorescence anisotropy study. In this case, it is observed that among the shorter tail surfactants, those with longer spacers (6 and 10 carbons) are responsible for a more pronounced disrupting effect upon the membrane, especially close to the lipid polar heads. Molecular dynamics simulation supports the most important findings and provides insight into the mechanism that governs this interaction. Accordingly, the interplay between tail and spacer length accounts for the differential vertical positioning of the gemini molecules and atom-density in the core of the bilayer, that provide a rationale for the experimental observations.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 15