Microscopic insights on the structural and dynamical aspects of Imidazolium-based surface active ionic liquid micelles

Bioactive Glycyrrhizic Acid Ionic Liquid Self-Assembled Nanomicelles for Enhanced Transdermal Delivery of Anti-Photoaging Signal Peptides

Sigal peptides have garnered remarkable efficacy in rejuvenating photoaged skin and delaying senescence. Nevertheless, their low solubility and poor permeability bring about a formidable challenge in their transdermal delivery. To address this challenge, bioactive ionic liquids (ILs) synthesized from natural glycyrrhizic acid (GA) and oxymatrine (OMT) with eminent biocompatibility is first prepared. The components ratios and inherent forming mechanisms of GA-OMT (GAO) are optimized by molecular dynamics simulations and density functional theory calculations. Remarkably, GAO can significantly improve the sparingly soluble properties of palmitoyl pentapeptide-4 (PAL-4), a model peptide drug. Subsequently, GAO self-assembled micelles loading PAL-4 (GAO/PAL-4-SM) are fabricated without additional auxiliary materials. The permeation and subcutaneous retention of PAL-4 are significantly promoted with 10wt.% GAO-SM. Moreover, GAO ILs facilitated PAL-4 permeation by enhancing its miscibility and interaction with stratum corneum (SC), offering a pulling effect and micellar structures for PAL-4, as elucidated by computational simulations. In cellular and animal photoaging experiments, GAO/PAL-4-SM possessed remarkable capabilities in boosting collagen and hyaluronic acid regeneration, mitigating inflammation and apoptosis, accelerating macrophage M2 polarization, thereby lessening skin wrinkles and leveraging elasticity. Collectively, the research innovatively designed an ILs self-assembled nano-micellar transdermal delivery system to enhance the permeability and anti-photoaging effect of signal peptides.

The Effect of Different Substances Embedded in Fullerene Cavity on Surfactant Self-Assembly Behavior through Molecular Dynamics Simulation

Fullerene-based amphiphiles are new types of monomers that form self-assemblies with profound applications. The conical fullerene amphiphiles (CFAs) have attracted attention for their uniquely self-assembled structures and have opened up a new field for amphiphile research. The CFAs and CFAs with different substances embedded in cavities are designed and their self-assembly behaviors are investigated using molecular dynamics (MD) simulations. The surface and internal structures of the micelles are analyzed from various perspectives, including micelle size, shape, and solvent-accessible surface area (SASA). The systems studied are all oblate micelles. In comparison, embedding Cl- or embedding Na+ in the cavities results in larger micelles and a larger deviation from the spherical shape. Two typical configurations of fullerene surfactant micelles, quadrilateral plane and tetrahedral structure, are presented. The dipole moments of the fullerene molecules are also calculated, and the results show that the embedded negatively charged Cl- leads to a decrease in the polarity of the pure fullerene molecules, while the embedded positively charged Na+ leads to an increase.

Exploring the Depth-Dependent Microviscosity inside a Micelle Using Butterfly-Motion-Based Fluorescent Probes

The viscosity distribution of micellar interiors from the very center to the outer surface is dramatically varied, which has been distinguished in theoretical models, yet it remains highly challenging to quantify this issue experimentally. Herein, a series of fluorophore-substituted surfactants DPAC-Fn (n = 3, 5, 7, 9, 11, 13, and 15) are developed by functionalizing the different alkyl-trimethylammonium bromides with the butterfly motion-based viscosity sensor, N,N'-diphenyl-dihydrodibenzo[a,c]phenazine (DPAC). The immersion depth of DPAC units of DPAC-Fn in cetrimonium bromide (C16TAB) micelles depends on the alkyl chain lengths n. From deep (n = 15) to shallow (n = 3), DPAC-Fn in C16TAB micelles exhibits efficient viscosity-sensitive dynamic multicolor emissions. With external standards for quantification, the viscosity distribution inside a C16TAB micelle with the size of ∼4 nm is changed seriously from high viscosity (∼190 Pa s) in the core center to low viscosity (∼1 Pa s) near the outer surface. This work provides a tailored approach for powerful micelle tools to explore the depth-dependent microviscosity of micellar interiors.

Effects of ionic liquids on biomembranes: A review on recent biophysical studies

Ionic liquids (ILs) have been emerged as a versatile class of compounds that can be easily tuned to achieve desirable properties for various applications. The ability of ILs to interact with biomembranes has attracted significant interest, as they have been shown to modulate membrane properties in ways that may have implications for various biological processes. This review provides an overview of recent studies that have investigated the interaction between ILs and biomembranes. We discuss the effects of ILs on the physical and chemical properties of biomembranes, including changes in membrane fluidity, permeability, and stability. We also explore the mechanisms underlying the interaction of ILs with biomembranes, such as electrostatic interactions, hydrogen bonding, and van der Waals forces. Additionally, we discuss the future prospects of this field.