The ionic strength effect on the DNA complexation by DOPC - gemini surfactants liposomes

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Petra Pullmannova (Author) Other; Margarida Bastos (Author) FCUP; Guangyue Y Bai (Author) Other; Sergio S Funari (Author) Other; Ivan Lacko (Author) Other; Ferdinand Devinsky (Author) Other; Jose Teixeira (Author) Other; Daniela Uhrikova (Author) Other

Journal

Title: Biophysical Chemistry

Vol. 160

Pages: 35-45

ISSN: 0301-4622

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 22 Citations

Scopus - 24 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-002-HGQ

DOI: 10.1016/j.bpc.2011.09.002

Abstract (EN): Liposome dispersions obtained from the mixture of gemini surfactants of the type alkane-alpha,omega-diyl-bis(alkyl-dimethylammonium bromide) and helper lipid DOPC create complexes with DNA showing a regular inner microstructure, identified by small angle X-ray diffraction as condensed lamellar phase (L-alpha(c)). In addition to the L-alpha(c) phase, a coexisting lamellar phase L-B was also identified in the complexes formed, with periodicities in the range similar to 8.8-5.7 nm, at ionic strengths corresponding to 50-200 mM NaCl. The periodicities of L-B phase did not correspond to those identified in liposome dispersion without DNA using small angle neutron scattering. The observed phase separation is shown to depend on the interplay between the surface charge density of cationic liposomes, ionic strength and method of complex preparation. The effect of ionic strength on complex formation was studied by isothermal titration calorimetry and zeta potential measurements. High ionic strength reduces the fraction of bound DNA in the complexes, and the isoelectric point is attained at a ratio of DNA/gemini surfactant which is lower than the one that can be estimated by calculation based on nominal charges of CLs and DNA.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11