Micelles of Lipid−Oligonucleotide Conjugates:  Implications for Membrane Anchoring and Base Pairing

Abstract

This report examines the organization properties of new fluorescent DNA-lipids, either alone in water or in interaction with 1-octyl-beta-d-glucopyranoside micelles or egg phosphatidylcholine vesicles. We first describe the design and the syntheses of the conjugates. Then, we use UV-Vis absorption, steady-state fluorescence emission, electron microscopy, and fluorescence correlation spectroscopy after two-photon excitation to show that these DNA-lipids form spherical micelles in aqueous solution and incorporate much better in micelles than in vesicles. We also investigate the significance of the lipophilic chains of these DNA-lipids on the melting behavior of the double-stranded hybrids: in water melting curves are broadened whereas in amphiphilic assemblies duplexes melt as the unconjugated controls. This work is expected to be useful for improving the rational design of antisense medicines.

o‐Nitrobenzyl Photolabile Protecting Groups with Red‐Shifted Absorption: Syntheses and Uncaging Cross‐Sections for One‐ and Two‐Photon Excitation

“…Under the same experimental conditions, the temporal evolution of the intensity I F (l Two-photon excitation: Our home-built two-photon excitation FCS setup has been previously reported. [56,63] Illumination is provided by a modelocked titanium-sapphire laser (Mira pumped by Verdi, Coherent) through a 60 , 1.2 NA water immersion objective (Olympus). The sample at 1 mm concentration was contained in a cuvette described in reference [56].…”

Double-tailed lipid modification as a promising candidate for oligonucleotide delivery in mammalian cells

“…Alternatively, the presence of two ether bonds in the structure of this LOC could be related to its homogeneous distribution in lipid membrane model systems, since ether-linked glycerophospholipids appear to be more loosely packed in membranes, thereby increasing their fluidity [49,50]. In contrast, the fact that Alexa 488-labeled C 28 -5′-ODN (compound 11) compound, that possess two neighboring alkyl chains, could be associated with model membranes is opposite to what it was observed by other authors who reported that a lipid-anchored oligonucleotide with two neighboring alkyl chains may tend to form stable supramolecular structures in an aqueous environment, making it difficult to insert into preformed membranes [51]. In that case the oligonucleotide was conjugated to a chalcone moiety bearing longer alkyl chains (2 × C 16 ) than those of C 28 -5′-ODN (2 × C 14 ).…”

Nucleosides with 5′‐Fixed Lipid Groups – Synthesis and Anchoring in Lipid Membranes

“…Because of their amphiphilic properties they can form interesting supramolecular structures, such as monolayer films, micelles and/or vesicles, [1][2][3][4][5][6][7][8] organogels [5] or multilamellar layers. [5,8] Normally their nucleobases are exposed to the aqueous phase, and they potentially can form complementary Watson-Crick base pairs. [8][9][10] The lipophilic substituent can also act as an anchor for fixing lipophilic nucleosides or oligonucleotides in biocompatible lipid membranes, again by exposing the nucleotides to the aqueous phase.…”

“…[5,8] Normally their nucleobases are exposed to the aqueous phase, and they potentially can form complementary Watson-Crick base pairs. [8][9][10] The lipophilic substituent can also act as an anchor for fixing lipophilic nucleosides or oligonucleotides in biocompatible lipid membranes, again by exposing the nucleotides to the aqueous phase. [11][12][13][14] Recently we could show that nucleosides with lipid moieties linked to the nucleobase anchor in giant unilamellar vesicles (GUVs) and large unilamellar vesicles (LUVs) composed of unilamellar phospholipid bilayers.…”