Studies on the formation of DNA - Cationic lipid composite films and DNA hybridization in the composites

Citation
M. Sastry et al., Studies on the formation of DNA - Cationic lipid composite films and DNA hybridization in the composites, J PHYS CH B, 105(19), 2001, pp. 4409-4414
Citations number
26
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHYSICAL CHEMISTRY B
ISSN journal
15206106 → ACNP
Volume
105
Issue
19
Year of publication
2001
Pages
4409 - 4414
Database
ISI
SICI code
1520-6106(20010517)105:19<4409:SOTFOD>2.0.ZU;2-X
Abstract
The formation of composite films of double-stranded DNA and cationic lipid molecules (octadecylamine, ODA) and the hybridization of complementary sing le-stranded DNA molecules in such composite films are demonstrated. The imm obilization of DNA is accomplished by simple immersion of a thermally evapo rated ODA film in the DNA solution at close to physiological pH. The entrap ment of the DNA molecules in the cationic lipid film is dominated by attrac tive electrostatic interaction between the negatively char ed phosphate bac kbone of the DNA molecules and the protonated amine molecules in the therma lly evaporated film and has been quantified using quartz crystal microgravi metry (QCM). Fluorescence studies of DNA-ODA composite films obtained by se quential immersion of the ODA matrix in the complementary single-stranded D NA solutions using ethidium bromide intercalator clearly showed that the hy bridization of the DNA single strands had occurred within the composite fil m. Furthermore, fluorescence studies of the preformed double-stranded DNA-O DA biocomposite film indicated DNA entrapment without distortion to the nat ive double-helical structure. The DNA-ODA biocomposite films have been furt her characterized with Fourier transform infrared (FTIR) and X-ray photoele ctron spectroscopy (XPS) measurements. The DNA-fatty lipid composite films would serve as model systems for understanding DNA-membrane interactions as well as in the study of DNA-drug/protein interactions. This approach also shows promise for the synthesis of patterned DNA films and consequent appli cation in disease detection and genome sequencing.