Supramolecular Assembly of Single-Tail ssDNA-Amphiphiles through π-π Interactions

In this work, we demonstrate the formation of supramolecular architectures from the assembly of single-tail single stranded DNA (ssDNA)-amphiphiles. Short ssDNA sequences of 10 nucleotides that were either unstructured or formed G-quadruplex secondary structures were conjugated to a single 4-(hexadecyloxy)benzamide tail, either directly or through a polycarbon (C₁₂) spacer. Conjugation of the ssDNA to the tail did not interfere with the G-quadruplex secondary structure of the ssDNA sequence. The ssDNA-amphiphiles self-assembled into ellipsoidal micelles, vesicles, nanotapes, and nanotubes. These nanotubes appeared to be formed by the rolling up of nanotapes. The increase of the hydrophobic block of the ssDNA-amphiphiles through the addition of a C₁₂ spacer led to an increase in wall thickness and nanotube diameter. The presence of π-π interactions, through the benzoic group, was verified via X-ray diffraction (XRD) and played a critical role in the formation of the different nanostructures. In contrast, ssDNA-amphiphiles with a single heptadecanoic acid tail self-assembled only into ellipsoidal micelles.

An analytical study of lipid-oligonucleotide aggregation properties

Lipid-oligonucleotides (LON) attract great interest as supramolecular scaffolds to improve the intracellular delivery of nucleic acids. Analytical characterization of LON assemblies is critical to formulation development, understanding in-vivo performance, as well as quality control. For this study, we selected LONs featuring different modifications on both oligonucleotide (with or without a G4 prone sequence) and lipid (mono or bis-alkyl chain covalently attached to the oligonucleotide sequence). Size exclusion chromatography (SEC) and, for the first time, capillary electrophoresis (CE) were investigated to study LON supramolecular self-assemblies. Results were correlated to those obtained with conventional physico-chemical characterization techniques i.e. gel electrophoresis, dynamic light scattering, and circular dichroism. In SEC, a separation between LON monomers and micelles was achieved in 5min on a TSK-gel G3000PW column at 70°C with 100% water, as mobile phase. CE conditions were optimized using a fused-silica capillary length of 10.0cm effective length at 15°C. Different background electrolytes were tested by varying the nature and the concentration of salts added. A sodium tetraborate buffer with 75mM NaCl appeared suitable to promote LON assembly. CE offers benefits to LON micelle analysis in terms of speed of analysis, high resolution, and low quantity of sample injected. Moreover, CE provides an appropriate tool to assess the impact of media of biological relevance on LON self-assembly. In this work, the key role of lipophilic tails and the formation of tetramolecular G-quadruplexes on the stability of LON micelles was confirmed.

Lipid and Nucleic Acid Chemistries: Combining the Best of Both Worlds to Construct Advanced Biomaterials

Hybrid synthetic amphiphilic biomolecules are emerging as promising supramolecular materials for biomedical and technological applications. Herein, recent progress in the field of nucleic acid based lipids is highlighted with an emphasis on their molecular design, synthesis, supramolecular properties, physicochemical behaviors, and applications in the field of health science and technology. In the first section, the design and the study of nucleolipids are in focus and then the glyconucleolipid family is discussed. In the last section, recent contributions of responsive materials involving nucleolipids and their use as smart drug delivery systems are discussed. The supramolecular materials generated by nucleic acid based lipids open new challenges for biomedical applications, including the fields of medicinal chemistry, biosensors, biomaterials for tissue engineering, drug delivery, and the decontamination of nanoparticles.

Controlling G-quadruplex formation via lipid modification of oligonucleotide sequences

G-quadruplexes (G4) represent attractive supramolecular scaffolds.

Synthesis and complementary self-association of novel lipophilic π-conjugated nucleoside oligomers

A series of lipophilic nucleosides comprising natural and non-natural bases that are π-conjugated to a short oligophenylene–ethynylene fragment has been synthesized and their respective association constants measured.