Glycoside nucleoside lipids (GNLs): An intrusion into the glycolipids’ world?

Nucleoside-Derived Low-Molecular-Weight Gelators as a Synthetic Microenvironment for 3D Cell Culture

For the last few decades, many efforts have been made in developing cell culture methods in order to overcome the biological limitations of the conventional two-dimensional culture. This paradigm shift is driven by a large amount of new hydrogel-based systems for three-dimensional culture, among other systems, since they are known to mimic some living tissue properties. One class of hydrogel precursors has received interest in the field of biomaterials, low-molecular-weight gelators (LMWGs). In comparison to polymer gels, LMWG gels are formed by weak interactions upon an external trigger between the molecular subunits, giving them the ability to reverse the gelation, thus showing potential for many applications of practical interest. This study presents the use of the nucleoside derivative subclass of LMWGs, which are glyco-nucleo-bola-amphiphiles, as a proof of concept of a 3D cell culture scaffold. Physicochemical characterization was performed in order to reach the optimal features to fulfill the requirements of the cell culture microenvironment, in terms of the mechanical properties, architecture, molecular diffusion, porosity, and experimental practicality. The retained conditions were tested by culturing glioblastoma cells for over a month. The cell viability, proliferation, and spatial organization showed during the experiments demonstrate the proof of concept of nucleoside-derived LMWGs as a soft 3D cell culture scaffold. One of the hydrogels tested permits cell proliferation and spheroidal organization over the entire culture time. These systems offer many advantages as they consume very few matters within the optimal range of viscoelasticity for cell culture, and the thermoreversibility of these hydrogels permits their use with few instruments. The LMWG-based scaffold for the 3D cell culture presented in this study unlocked the ability to grow spheroids from patient cells to reach personalized therapies by dramatically reducing the variability of the lattice used.

Biomaterials for Three-Dimensional Cell Culture: From Applications in Oncology to Nanotechnology

Three-dimensional cell culture has revolutionized cellular biology research and opened the door to novel discoveries in terms of cellular behavior and response to microenvironment stimuli. Different types of 3D culture exist today, including hydrogel scaffold-based models, which possess a complex structure mimicking the extracellular matrix. These hydrogels can be made of polymers (natural or synthetic) or low-molecular weight gelators that, via the supramolecular assembly of molecules, allow the production of a reproducible hydrogel with tunable mechanical properties. When cancer cells are grown in this type of hydrogel, they develop into multicellular tumor spheroids (MCTS). Three-dimensional (3D) cancer culture combined with a complex microenvironment that consists of a platform to study tumor development and also to assess the toxicity of physico-chemical entities such as ions, molecules or particles. With the emergence of nanoparticles of different origins and natures, implementing a reproducible in vitro model that consists of a bio-indicator for nano-toxicity assays is inevitable. However, the maneuver process of such a bio-indicator requires the implementation of a repeatable system that undergoes an exhaustive follow-up. Hence, the biggest challenge in this matter is the reproducibility of the MCTS and the associated full-scale characterization of this system's components.

Self-Assembly of Nucleoside-Derived Low-Molecular-Weight Gelators: A Thermodynamics and Kinetics Study on Different Length Scales

Biocompatible materials are of paramount importance in numerous fields. Unlike chemically bridge polymer-based hydrogels, low-molecular-weight gelators can form a reversible hydrogel as their structures rely on noncovalent interaction. Although many applications with this type of hydrogel can be envisioned, we still lack their understanding due to the complexity of their self-assembly process and the difficulty in predicting their behaviors (transition temperature, gelation kinetics, the impact of solvent, etc.). In this study, we extend the investigations of a series of nucleoside-derived gelators, which only differ by subtle chemical modifications. Using a multitechnique approach, we determined their thermodynamic and kinetic features on various scale (molecular to macro) in different conditions. Monitored at the supramolecular level by circular dichroism as well as macroscopic scales by rheology and turbidimetry, we found out that the sol-gel and gel-sol transitions are greatly dependent on the concentration and on the mechanisms that are probed. Self-assembly kinetics depends on hydrogel molecules and is modulated by temperature and solvent. This fundamental study provides insight on the impact of some parameters on the gelation process, such as concentration, cooling rate, and the nature of the solvent.

A supramolecular hydrogel prepared from a thymine-containing artificial nucleolipid: study of assembly and lyotropic mesophases

An artificial nucleolipid containing thymine, a triazole-ring, and phosphatidylcholine (TTPC) moieties was prepared by copper catalyzed azide alkyne cycloaddition (CuAAC) under aqueous conditions. The resulting TTPC molecules assembled in situ into a fibrous aggregation. The study of the TTPC fiber assembly using XRD and NMR spectroscopy revealed that the formation of fibers was driven by the unique combination of the lipid and nucleobase moieties in the structure of TTPC. At a critical TTPC concentration, entanglement of the fibers resulted in the formation of a supramolecular hydrogel. Investigation of the lyotropic mesophases in the TTPC supramolecular hydrogel showed the presence of multiple phases including two liquid crystal phases (i.e., nematic and lamellar), which have a certain degree of structural order and are promising templates for constructing functional biomaterials.

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.

Decontamination of nanoparticles from aqueous samples using supramolecular gels

We report for the first time, a facile and general method for the quantitative removal of nanoparticles from aqueous waste using supramolecular gels.

Insights into low molecular mass organic gelators: a focus on drug delivery and tissue engineering applications

In recent years low molecular mass organic gelators (LMOGs) have gained increasing interest as an alternative biomaterial to polymer derived gels, with potential applications in drug delivery and tissue engineering. LMOGs are small organic molecules which self-assemble in water or organic solvents forming a 3D network that entraps the liquid phase resulting in gel formation. In this review, we report the classification of LMOGs into hydrogelators and gelators of organic solvents and we discuss the techniques commonly used to characterise the gels of these gelators with particular reference to specific applications of LMOGs in drug delivery and tissue engineering.

Nucleolipids as building blocks for the synthesis of 99mTc-labeled nanoparticles functionalized with folic acid

Nucleoside-lipids are efficient bio-inspired amphiphiles for the construction of nanoparticles for image-guided therapy applications.

Glycosyl-Nucleolipids as new bioinspired amphiphiles

Four new Glycosyl-NucleoLipid (GNL) analogs featuring either a single fluorocarbon or double hydrocarbon chains were synthesized in good yields from azido thymidine as starting material. Physicochemical studies (surface tension measurements, differential scanning calorimetry) indicate that hydroxybutanamide-based GNLs feature endothermic phase transition temperatures like the previously reported double chain glycerol-based GNLs. The second generation of GNFs featuring a free nucleobase reported here presents a better surface activity (lower γ_lim) compared to the first generation of GNFs.