EDTA-induced self-assembly of cationic lipid-DNA multilayers near a monolayer-covered air-water interface (original) (raw)
Related papers
Journal of Physical Chemistry B, 2010
In the present series of papers, we describe the results of a systematic study on the anchoring of cholesteroltagged oligonucleotides to phospholipids bilayers followed by membrane-assisted hybridization of the complementary strand in solution. This paper describes the anchoring of novel cholesterol-modified DNA-18mers in supported lipid bilayers (SLB) of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine: we compared the behavior of two anchoring functionalities differing in the number of cholesterol units and in the length of a spacer group. Quartz Crystal Microbalance with impedance monitoring (QCM-Z) measurements showed that both oligonucleotides insert into the bilayer membrane through cholesterol anchoring; however, dramatic differences, in terms of surface organization and thickness, are found as the number of anchoring units increases. In the case of multiple cholesterol units, a peculiar three-regimes concentration dependence was revealed and correlated to the effective size of the adsorbing units. Interestingly, for high oligonucleotide concentration, the adsorption process was rationalized in terms of a compaction model of amphiphilic DNA molecules. QCM-Z temperature cycles of the SLB-anchored double strands provided clear evidence for reversible hybridization at the bilayer interface.
The interaction between DNA and cationic lipid films at the air–water interface
Journal of Colloid and Interface Science, 2005
The interaction between DNA and positively charged dioctadecyldimethylammonium bromide (DODAB) and DODAB/disteroylphosphatidylcholine (DSPC) monolayers at the air-aqueous interface was studied by a combination of the surface film balance and Brewster angle microscopy. In presence of DNA, the Π-A isotherm of the cationic monolayer shifts to larger mean molecular areas due to the electrostatic interaction with DNA while the typical liquid expanded-liquid condensed phase transition for DODAB monolayers disappear and the monolayer remains to be in the liquid expanded phase. Furthermore, the morphology of the film dramatically changes, where the large dendritic-like condensed aggregates observed for DODAB monolayers vanish. The charge density of the monolayer was varied by using mixed monolayers with the zwitterionic DSPC and no large effect was observed on the interaction with DNA. By modeling the electrostatic interactions with the linearized Poisson-Boltzmann equation using the finite-element method and taking into account the assumption in the dielectric constants of the system, it was possible to corroborate the expansion of the cationic monolayer upon interaction with DNA as well as the fact that DNA does not seem to penetrate into the monolayer.
DNA and lipid bilayers: self-assembly and insertion
Journal of The Royal Society Interface, 2008
DNA-lipid complexes are of biomedical importance as delivery vectors for gene therapy. To gain insight into the interactions of DNA with zwitterionic and cationic (dimyristoyltrimethylammonium propane (DMTAP)) lipids, we have used coarse-grained molecular dynamics simulations to study the self-assembly of DPPC and DPPC/DMTAP lipid bilayers in the presence of a DNA dodecamer. We observed the spontaneous formation of lipid bilayers from initial systems containing randomly placed lipids, water-counterions and DNA. In both the DPPC and DPPC/DMTAP simulations, the DNA molecule is located at the water-lipid headgroup interface, lying approximately parallel to the plane of the bilayer. We have also calculated the potential of mean force for transferring a DNA dodecamer through a DPPC/DMTAP bilayer. A high energetic barrier to DNA insertion into the hydrophobic core of the bilayer is observed. The DNA adopts a transmembrane orientation only in this region. Local bilayer deformation in the vicinity of the DNA molecule is observed, largely as a result of the DNA-DMTAP headgroup attraction.
Interaction of DNA Oligomers with Cationic Lipidic Monolayers: Complexation and Splitting
Langmuir, 2007
Interactions of native DNA with octadecylamine (ODA) and hexadecymdimethylammonium bromide (HTAB) monolayers at the air/water interface were studied by π-A isotherms, ellipsometry, and X-ray reflectivity. We show that the microscopic structure of ODA-DNA complexes is definitely consistent with a single-stranded form for DNA. On the contrary, with HTAB, DNA complexes in its native form. The crucial difference in the behavior of these two fairly similar lipids is due to the presence of the amine group in ODA. These results should be relevant to applications such as DNA chips and sensors.
Bioelectrochemistry, 2003
We studied the properties of lipid monolayers formed at the air -water interface composed of dioleoylphosphatidylcholine (DOPC) with incorporated short (19-mer) oligonucleotides. These oligonucleotides were modified by oleylamine at both (3Vand 5V ) terminals or only at one (3V ) terminal. Interaction of single-stranded (19-mer) oligonucleotides without oleylamine with DOPC monolayers resulted only in slight increase of surface pressure and the area per phospholipid molecule, while more substantial and significant increase of these values were observed following incorporation of oligonucelotides modified by oleylamine. This influence is similar for both types of oligonucleotide modifications. However, considerable differences in changes of monolayer properties took place after hybridization with complementary oligonucleotides. The hybridization of oligonucleotides with the DNA modified by oleic acid at both 3Vand 5Vterminals at the surface of lipid monolayer resulted in further increase of surface pressure and in the increase of the area per phospholipid molecule, while decrease of both the surface pressure and the area per phospholipid molecules were observed for hybridization with DNA modified by oleic acid at 3Vterminal. It is possible that in latter case, the hybridization caused the loss of hybridized molecules from monolayers. Interaction of noncomplementary chains with DOPC monolayers with incorporated oleyl acid-modified DNA also influenced the properties of monolayers, but the effect was weaker in comparison with that observed for complementary chains. D
Molecular Restructuring of Water and Lipids upon the Interaction of DNA with Lipid Monolayers
Journal of the …, 2010
Understanding the molecular mechanism of DNA/lipid interaction is critical in optimizing the use of lipid cofactors in gene therapy. Here, we address this question by employing label-free vibrational sum frequency (VSF) spectroscopy to study the interaction of DNA with lipid monolayers of the cationic lipids DPTAP(1,2-dipalmitoyl-3-trimethylammonium-propane) and diC14-amidine as well as the zwitterionic lipid DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) in the presence and absence of calcium. Our approach has the advantage both of allowing us to explicitly probe intermolecular interactions and of providing insight into the structure of water and lipids around DNA at the lipid interface. We find, by examination of the OD stretch of interfacial D 2 O, that water structure differs markedly between systems containing DNA adsorbed to cationic and those that contain DNA adsorbed to zwitterionic lipid monolayers (in the presence or absence of Ca 2+). The spectral response of interfacial water in the cationic system is consistent with a highly structured, undercoordinated, structural 'type' of water. Further, by investigation of CH stretch modes of the diC14-amidine lipid tails, we demonstrate that the adsorption of DNA to this lipid leads to increased ordering of lipid tails.
DNA Condensation at Freestanding Cationic Lipid Bilayers
Physical Review Letters, 2010
We describe a previously unreported coil-globule transition of DNA electrostatically bound to a freestanding fluid cationic lipid membrane. The collapse of a DNA coil into a compact globule takes place after the DNA molecule attaches in an extended conformation to the membrane. DNA condensation is favored at a higher cationic lipid content, while at lower membrane charge densities coexistence of DNA random coils, partially collapsed conformations, and globules is observed.
Beilstein journal of organic chemistry, 2015
A series of six cyanine-5-labeled oligonucleotides (LONs 10-15), each terminally lipophilized with different nucleolipid head groups, were synthesized using the recently prepared phosphoramidites 4b-9b. The insertion of the LONs within an artificial lipid bilayer, composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), was studied by single molecule fluorescence spectroscopy and microscopy with the help of an optically transparent microfluidic sample carrier with perfusion capabilities. The incorporation of the lipo-oligonucleotides into the bilayer was studied with respect to efficiency (maximal bilayer brightness) as well as stability against perfusion (final stable bilayer brightness). Attempts to correlate these parameters with the log P values of the corresponding nucleolipid head groups failed, a result which clearly demonstrates that not only the lipophilicity but mainly the chemical structure and t...