DNA Alignment at Cationic Lipid Monolayers at the Air/Water Interface

Abstract

The interaction of DNA with other DNA and with charged interfaces is of utmost importance for understanding nonviral transfection and DNA diagnostics with optimized chips. This can be studied in detail using Langmuir monolayers of cationic lipids as soft surface of a DNA containing subphase. The positional order of the lipid and the DNA sublattices can be studied by synchrotron X-ray diffraction under continuous variation of parameters such as molecular density or surface pressure. It is shown that DNA binding condenses the membrane surface, and the resulting structure is determined by the interplay of DNA-lipid and DNA-DNA interactions.

Characterization limits of a polymer adsorbed under a monolayer by GIXD measurements

“…The 0.88 value appears as the maximum value reached for the DODA monolayer at the air-water interface, whereas, ideally, x should reach 1 (after a sufficiently long time). Symietz et al [22] have obtained this unit value. The difference between the two results can be explained by different compression rates and/or time intervals before compression of the monolayer.…”

“…The DODA monolayer has already been characterized at the air-water interface by ellipsometry [17], attenuated total reflection [18], reflection spectroscopy [19], and Brewster angle microscopy [20,21], and recently, some grazing incidence Xray diffraction experiments have been reported [22]. Initially, the DODA monolayer is characterized on water in order to establish a reference under the same experimental conditions as those used for the spontaneous polymerization.…”

Physical–Chemical Properties and Transfection Activity of Cationic Lipid/DNA Complexes

“…If DNA adsorbs to a Langmuir monolayer and forms a one-dimensional periodicity, a diffraction peak ascribable to DNA lateral ordering appears at low Q xy values. [39] Assuming that DNA adsorbs to the lipid monolayer as aligned cylinders, it is possible to calculate the lattice spacing (d DNA ) as a distance between neighboring DNA helixes by d = 2p/ Q xy , where Q xy is the maximum of the Lorentz curve.…”

X-ray reflectivity studies on the deoxyribonucleic acid adsorption by 3-β-[N-(N',N'-dimethylaminoethane)carbamoyl]cholesterol monolayer with divalent ions

“…Although many studies have made of the structure and interaction of cationic lipid-DNA complexes in bulk and in solution (Koltover et al, 1998(Koltover et al, , 2000McManus et al, 2003;Wetzer et al, 2001), there are few studies on their interactions at the air-water interface. Recently, there have been some studies on using the Langmuir-Blodgett (LB) technique to study the cationic lipid-DNA interaction at the air-water interface (Kago et al, 1999;Okahata et al, 1996;Chen, Wang, Shen et al, 2002;Sastry et al, 2000;Symietz et al, 2004;McLoughlin et al, 2005;Cá rdenas et al, 2005). The DNA molecules adsorbed onto supported cationic bilayers could form an aligned two-dimensional structure with regular spacing as revealed by atomic force microscopy studies (Fang & Yang, 1997).…”

“…Okahata et al (1996) reported that when dipping from the cationic 2C 18 -glu-N + /DNA monolayer, the DNA strands were aligned along the dipping direction with a spacing of 41 Å , as found by X-ray diffraction. The in-situ grazing-incident diffraction study of Symietz et al(2004) showed that DNA adsorbed under a cationic lipid methyltrioctadecylammonium bromide (TODAB) monolayer at the airwater has an ordered structure with a DNA spacing from 40 to 32 Å as the surface pressure increased from 10 to 50 mN m…”