The review on properties of solid catanionic surfactants: Main applications and perspectives of new catanionic surfactants and compounds with catanionic assisted synthesis

Divergent Effects of Cholesterol on the Structure and Fluidity of Liposome and Catanionic Vesicle Membranes

Lipid-like ion-pair amphiphile vesicles, or catanionic vesicles, have emerged as potential drug carriers. The effects of cholesterol on the properties of catanionic vesicles have not yet been systematically studied. Here, we compared the effects of cholesterol on the structures and fluidities of dipalmitoylphosphatidylcholine liposomes and catanionic vesicles with similar main transition temperatures (T_m ). For liposomes, fluorescence anisotropy (FA) thermograms reveal typical condensing and disordering effects of cholesterol above and below T_m , respectively. In contrast, FA and molecular simulation data reveal that catanionic bilayers below T_m are more fluidic due to shorter alkyl chains. This leads to only condensing effects of cholesterol for catanionic vesicles at all temperatures. Our results provide important insights into the fabrication of catanionic vesicles as novel drug carriers.

Lamellar Tetragonal Symmetry of Amphiphilic Thermotropic Ionic Liquid Crystals in the Framework of Other Closely Related Highly Ordered Structures

An overview of the chemical compounds forming the rare smectic T phases is presented with references to the historical context. Thermodynamics (transition temperatures, enthalpies) along with the factors (stereochemical constraints, electrostatic interactions, aliphatic chain stacking, intermolecular forces) contributing to the adoption of tetragonal scaffolds are also discussed. Characteristic optical microscopy textures and X-ray diffraction patterns are presented. In parallel, a comparison of the geometrical parameters such as distances between atoms, molecular areas, volumes, and lattice parameters with the closest two-dimensional and three-dimensional organizations, is performed.

Stable Ethosome-like Catanionic Vesicles for Transdermal Hydrophilic Drug Delivery with Predictable Encapsulation Efficiency

Lipid-like pseudo-double-chained catanionic surfactants have emerged as the attractive materials to prepare potential vesicular carriers in drug and gene delivery applications. In particular, the semi-spontaneous process has been developed to fabricate ethosome-like catanionic vesicles for the transdermal drug delivery. In this work, Arbutin (a water-soluble drug) encapsulation efficiency of ethosome-like catanionic vesicles fabricated from decyltrimethylammonium-tetradecylsulfate (DeTMA-TS, CH₃(CH₂)₉ N(CH₃)₃-CH₃(CH₂)₁₃SO₄) and decyltrimethylammonium-dodecylsulfate (DeTMA-DS, CH₃(CH₂)₉N(CH₃)₃-CH₃(CH₂)₁₁SO₄) with various amounts of ethanol and cholesterol in tris buffer solution was experimentally determined. A simple unilamellar vesicle (ULV) model, resulting in the theoretical encapsulation efficiency within ±10% error for most vesicle compositions, was also developed. Such agreement indirectly confirmed the formation of unilamellar vesicles by the preparation method. Stable ethosome-like catanionic vesicles by using catanionic surfactants with the aid of suitable amounts of ethanol and cholesterol, which led to polydispersity index (PDI) values of vesicle size distribution less than 0.3, were successfully prepared and their hydrophilic drug encapsulation efficiencies can be accurately predicted. Furthermore, the linear correlations of the trap volume ratio with both vesicle size and concentration of the extra added CHOL also provide important guidelines for controlling the drug loading of ethosome-like catanionic vesicles. The accomplishments reached for the novel vesicles are useful for developing their transdermal drug delivery applications.

Ionic-surfactants-based thermotropic liquid crystals

Ionic surfactants can be combined with various functional groups through electrostatic interaction, resulting in a series of thermotropic liquid crystals (TLCs).

Hyperbranched Polyamidoamine Surfactants: Synthesis, Characterization and Evaluation as Biocides

Different generations of cationic hyperbranched quaternary ammonium polyamidoamine dendrimers (PAMAM) with methyl ester end group (G-0.5, G 0.5, G1.5 and G 2.5) were synthesized. Preparation of these dendrimers was carried out via alternative steps of an aza Michael addition reaction (of piperazine as core center molecule) and amidation reaction by ethylene diamine. Each aza Michael addition step was followed by a quaternization step using alkyl bromide with different chain length (4, 8 or 12) carbon atoms. The chemical structures of the prepared dendrimers were confirmed using FTIR, 1H-NMR spectra and elemental analysis for two generations as representative compounds. Also their surface activity has been studied and their surface parameters including surface and interfacial tension, emulsification power, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area were determined. The prepared quaternized dendrimers were tested as antimicrobial agents against different strains of bacteria, yeast and fungi. The results showed a significant antimicrobial efficacy of the synthesized surfactants.

Cooperative Effects of Zwitterionic-Ionic Surfactant Mixtures on the Interfacial Water Structure Revealed by Sum Frequency Generation Vibrational Spectroscopy

Cooperative effects of a series of equimolar binary zwitterionic-ionic surfactant mixtures on the interfacial water structure at the air-water interfaces have been studied by sum frequency generation vibrational spectroscopy (SFG-VS). For zwitterionic surfactant palmityl sulfobetaine (SNC₁₆), anionic surfactant sodium hexadecyl sulfate (SHS), and cationic surfactant cetyltrimethylammonium bromide (CTAB) with the same length of alkyl chain, significantly enhanced ordering of interfacial water molecules was observed for the zwitterionic-anionic surfactant mixtures SNC₁₆-SHS, indicating that SNC₁₆ interacts more strongly with SHS than with CTAB because of the strong headgroup-headgroup electrostatic attraction for SNC₁₆-SHS. Meanwhile, the SFG amplitude ratio of methyl and methylene symmetric stretching modes was used to verify the stronger interaction between SNC₁₆ and SHS. The conformational order indicator increased from 0.64 for SNC₁₆ to 7.17 for SNC₁₆-SHS but only 0.94 for SNC₁₆-CTAB. In addition, another anionic surfactant sodium dodecyl sulfate (SDS) was introduced to study the influence of chain-chain interaction. Decreased SFG amplitude of interfacial water molecules for SNC₁₆-SDS was observed. Therefore, both the headgroup-headgroup electrostatic interaction and chain-chain van der Waals attractive interaction of the surfactants play an important role in enhancing the ordering of interfacial water molecules. The results provided experimental and theoretical bases for practical applications of the surfactants.