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Lipid nanoparticles (LNPs) are advanced core-shell particles for messenger RNA (mRNA) based therapies that are made of polyethylene glycol (PEG) lipid, distearoylphosphatidylcholine (DSPC), cationic ionizable lipid (CIL), cholesterol (chol), and mRNA. Yet the mechanism of pH-dependent response that is believed to cause endosomal release of LNPs is not well understood. Here, we show that eGFP (enhanced green fluorescent protein) protein expression in the mouse liver mediated by the ionizable lipids DLin-MC3-DMA (MC3), DLin-KC2-DMA (KC2), and DLinDMA (DD) ranks MC3 = KC2 > DD despite similar delivery of mRNA per cell in all cell fractions isolated. We hypothesize that the three CIL-LNPs react differently to pH changes and hence study the structure of CIL/chol bulk phases in water. Using synchrotron X-ray scattering a sequence of ordered CIL/chol mesophases with lowering pH values are observed. These phases show isotropic inverse micellar, cubic Fd3m inverse micellar, inverse hexagonal HII and bicontinuous cubic Pn3m symmetry. If polyadenylic acid, as mRNA surrogate, is added to CIL/chol, excess lipid coexists with a condensed nucleic acid lipid Hc II phase. The next-neighbor distance in the excess phase shows a discontinuity at the Fd3m inverse micellar to inverse hexagonal HII transition occurring at pH 6 with distinctly larger spacing and hydration for DD vs. MC3 and KC2. In mRNA LNPs, DD showed larger internal spacing, as well as retarded onset and reduced level of DD-LNP-mediated eGFP expression in vitro compared to MC3 and KC2. Our data suggest that the pH-driven Fd3m-H II transition in bulk phases is a hallmark of CIL-specific differences in mRNA LNP efficacy. [ABSTRACT FROM AUTHOR]

The molten phase of transition metal and lithium salts self‐assemble with non‐ionic surfactants to form lyotropic liquid crystalline (LLC) mesophases, which are important in the development of gel‐electrolytes and mesoporous materials. Here, we show that LiH2PO4 forms a semi‐stable LLC mesophase with 10‐lauryl ether (C12H25(OCH2CH2)10OH, C12E10), decoded as Li−EO−X (X is LiH2PO4/C12E10 mole ratio and between 2 and 200). The stability of the Li−EO−X phase is improved by increasing salt concentration (X>20) in the media. The semi‐stable Li−EO−X mesophase is further stabilized by adding either water by controlling the humidity or H3PO4 (PA) to the media. The phase behaviour of the above samples was investigated using POM, XRD, conductivity, and ATR‐FTIR measurements. The addition of PA not only brings stability and higher conductivity (increase from 0.1 to 8.9 mS/cm) to the mesophase but also produce an LLC gel‐electrolyte with a high buffer capacity that may be useful and important in various applications. [ABSTRACT FROM AUTHOR]

The collective behavior of the shortest DNA oligomers in high concentration aqueous solutions is an unexplored frontier of DNA science and technology. Here we broaden the realm of DNA nanoscience by demonstrating that single-component aqueous solutions of the DNA 4-base oligomer GCCG can spontaneously organize into three-dimensional (3D) periodic mesoscale frameworks. This oligomer can form B-type double helices by Watson-Crick (WC) pairing into tiled brickwork-like duplex strands, which arrange into mutually parallel arrays and form the nematic and columnar liquid crystal phases, as is typical for long WC chains. However, at DNA concentrations above 400 mg/mL, these solutions nucleate and grow an additional mesoscale framework phase, comprising a periodic network on a three-dimensional body-centered cubic (BCC) lattice. This lattice is an array of nodes (valence-8, each formed by a pair of quadruplexes of GCCG terminal Gs), connected with a separation of 6.6 nm by struts (6-GCCG-long WC duplexes). This 3D-ordered DNA framework is of low density (DNA volume fraction ∼0.2), but due to its 3D crystal structure, it is osmotically incompressible over its phase range. Atomistic simulations confirm the stability of such structures, which promise to form the basis of families of simply and inexpensively made nanoscale frameworks for templating and selection applications.

Taking inspiration from diatom hierarchically organized porosity, synthetic porous monoliths have been synthesized through rational designs while combining sol–gel chemistry, emulsions, Pickering-based emulsions, and lyotropic mesophases. We have described the synthesis of the Si(HIPE) series employing traditional emulsions to tune the macroscopic void diameters and cationic surfactant molecules to both stabilize the oil/water interface at the macroscopic length scale and create vermicular poorly organized porosity at the mesoscopic length scale. In a second part, while substituting surfactant molecules with modified silica nanoparticles acting as emulsion-stabilizers, we depict the possibility of tuning independently the macroscopic cell diameters and the cell junctions via Pickering emulsions employed as templates, leading to the Si(PHIPE) series presenting both monodiperse macroscopic void and cell junction diameters. Finally taking the synergetic effect of nonionic surfactants and a kosmotrope salt effect we show that it is possible generating self-standing Si(HIPE) bearing high organized mesoporosity while addressing the SBA-15-Si(HIPE) series. Taking inspiration from diatom hierarchically organized porosity, synthetic porous self-standing silica foams have been obtained through rational designs where sol–gel chemistry, emulsions, Pickering-based emulsions and lyotropic mesophases are advantageously combined. Highlights: Lyotropic mesophases, direct emulsions and sol–gel chemistry can be integrated toward the generation of self-standing foams where the macroscopic voids can be tuned while varying the starting emulsion volume fraction, addressing thereby the Si(HIPE) series. Pickering-based emulsions can be employed to shape macrocellular foams bearing high monodisperse character of both macroscopic cells and cell junction diameters, each feature being tunable independently, generating thus the Si(PHIPE) series. P123 nonionic surfactant, (NH4)2SO4 salt and direct emulsion are combined to generate self-standing monolith foams bearing a very high organization of the voids at the mesoscopic length, leading to the SBA-15-Si(HIPE) series. Kosmotrope-Chaotrope balance is introduced in sol–gel chemistry as a tool to enhance silica polycondensation, beyond and additionally to the well-known salt screening and ionic strength effects. [ABSTRACT FROM AUTHOR]

Thermotropic mesogens of different chemical nature - 4-pentyl-4′-cyanobiphenyl (5CB), azoxy nematic ZhK-440, and cholesteryl oleyl carbonate (COC) were introduced as dopants to hydrated DPPC, with their effects on phase transitions recorded by DSC. When mesogen pairs (5CB + ZhK-440 and 5CB + COC) were added at constant total concentration, dependence of transition temperature toLαphase on 5CB concentration was linear for COC and nonlinear for ZhK-440, with effects of cyanobiphenyl-azoxybenzene charge transfer complexes manifested in both types of mesophases. Such dual doping of hydrated DPPC allows modeling of drug-membrane interactions in the case of joint application of different drugs. [ABSTRACT FROM PUBLISHER]

The lyotropic Lα-phase of hydrated dipalmitoylphosphatidylcholine has been proposed as a solvent medium for modeling the effects of membranotropic agents upon cell membranes, including interactions between different agents inside the membrane. For quasibinary systems containing bisquaternary ammonium compounds decamethoxinum or aethonium and 2,5-dihydroxybenzoic acid, calorimetry data allowed us to establish the stoichiometry of the intermolecular complexes incorporated in the membrane. The interaction mechanisms have been clarified using additional data obtained with tetramethylammonium and l-menthol, which model the moieties of the decamethoxinum molecule separated by the alkyl chain. Possible implications of the obtained results for pharmacology are discussed. [ABSTRACT FROM AUTHOR]

Abstract: In this study, new hybrid Organo-Si(HIPE) macrocellular foams have been synthesized via sol–gel process, direct emulsions and lyotropic mesophases as templating agents followed by a final grafting process of silane organically modified. A variety of sililated groups, including methyl, benzyl, amines, mercapto, pyrrol and dinitro have been successfully grafted. The effects of the various organosilanes on the physical chemical properties of the resulting materials have been thoroughly characterized using several analytical techniques (SEM, TEM, SAXS, mercury porosimetry, nitrogen adsorption isotherms, FTIR, 29Si MAS NMR). If the resulting grafted compounds, labeled gOrgano-Si(HIPE), exhibit the same macroscopic texture than the starting silica open-cell matrices, we found a reduction of the mesoporosity depending upon the size of the organic moiety in use and the associated enhance molecular hindrance. Final porous materials functionalized at the molecular level are potential outstanding candidates for applications such as heterogeneous catalyst, scavenger and sensor. [Copyright &y& Elsevier]

Abstract: The use of surfactant mesophases such as vesicular and lyotropic mesophases as templates for the preparation of nanostructured polymers by polymerization is reviewed. Recent developments using polymerizable and polymeric surfactants in mesophase formation and polymerization are also represented with examples. The formations of various novel materials including nanocapsules, vesicle-polymer architecture, mesoporous polymers and functional nano-composites which would be unobtainable through conventional techniques are highlighted. The effects of reaction thermodynamics and kinetics on templated polymerizations are also discussed. [Copyright &y& Elsevier]

Self-organized surfactant solutions, such as microemulsions, vesicular solutions or dispersions, or lyotropic mesophases can serve as templates for the structure directed synthesis of organic polymers. Recent developments of templating within these equilibrium nanostructured fluids are reviewed. Depending on the template structure and the reaction conditions, the outcomes may be polyampholytes, amphiphiles, nanoparticles, hollow spheres, or mesoporous polymers. For each structure and morphology, the final product materials reflect a delicate balance between phase behavior and the reaction and mass transfer parameters that set structure. Experimental and theoretical aspects of reaction kinetics and thermodynamics such as monomer partitioning, swelling behavior and polymerization-induced phase separation are discussed. [Copyright &y& Elsevier]

Analogously to aqueous K-soap/water systems already examined, the glycerol-containing systems KC/G (KC; n=12, 14, 16, 18, 22; G=glycerol) are also able to build up hexagonal, lamellar, optically isotropic, gel-like and crystalline phases. These preliminary phases have been identified by texture observations of contact samples and singular concentrations with a polarizing microscope. The appertaining phase regions have been plotted in the binary phase diagrams. Correspondences and differences between these systems have been elucidared by drawing a comparison. Mosaic texture and 'oily streaks' are typical of the lamellar phase. Spherulites are mainly found in the heterogeneous two-phase region lamellar/isotropic. The textures of the hexagonal phase are of fan-like morphology. The appearance of the gel phase texture resembles globular or curd-like structures. The influences exerted by the increasing chain lengths of the K-soaps (KC, n=12-22) on the phase regions in the binary systems (KC/G) can be described as follows. The concentrations required for forming the hexagonal and the lamellar phase respectively are shifted toward lower K-soap concentrations. The concentration range in which the hexagonal phase is stable is diminished. The temperature range in which the hexagonal phase is stable becomes larger. The upper temperature limit of the lamellar phase region is lowered. Binary aqueous and glycerol-containing K-soap systems have the following common features: The hexagonal phase is built up at low soap concentrations. The lamellar phase is formed at high soap concentrations. The lamellar phase is formed at high soap concentrations. An optically isotropic region is inserved between the lamellar and the hexagonal phase in aqueous and glycerol-containing systems of the types KC, KC and KC. The temperature of the transition hexagonal↔isotropic phase ( H↔S) runs through a maximum value. On increasing the chain length the formation of the hexagonal phase is shifted in the direction of lower soap concentrations. Aqueous and glycerol-containing K-soap mixtures differ in the following essential points: The lyotropic mesophases ( H, L, I) of aqueous systems are formed at considerably lower soap concentrations than the corresponding phases of glycerol-containing systems. The lamellar phases of aqueous systems reach the regions of very low soap concentrations. The lyotropic mesophases of aqueous systems are built up at temperatures lower than the corresponding ones of glycerol-containing mixtures. In aqueous systems the concentration range of the lamellar phase increases with increasing chain length, in contrast to glycerol-containing systems where it is diminished. [ABSTRACT FROM AUTHOR]

Studies by Pulsed Field Gradient NMR (PFG-NMR) methods and other physico-chemical experiments have been used to clarify the processes connected with water self-diffusion in mixtures formed by water and Triton TX-100. In micellar solutions the solvent diffusive trend is related to micelle hydration and, to a much less extent, to micelle size and shape. Hydration numbers from PFG-NMR are close to those obtained by viscosity experiments. In solution phases of the reversed kind, water in oil, water self-diffusion data suggest that aqueous domains are large and bicontinuous. Water self-diffusion in the hexagonal lyotropic mesophase has been interpreted by introducing a geometrydependent contraint, $$\tilde f$$ , termed 'structural factor', which is related to the parameters of the phase. [ABSTRACT FROM AUTHOR]

The formation of aqueous, lyotropic phases of the biopolymers xanthan ( M = 1.6·10) and schizophyllan ( M= 335 000) is investigated with stationary shear flow and oscillatory measurements, as well as with the aid of polarization microscopy, because these polymers show very different viscoelastic properties from coiled vinyl polymers. Xanthan and schizophyllan exhibit the same typical behavior observed in anisotropic solutions when the viscosity is plotted as a function of concentration and of shear rate. It has also been observed that the first normal stress difference for concentrated xanthan solutions shows a saturation effect at increasing shear rate. In oscillatory measurements only schizophyllan exhibits an maximum for the storage modulus. The absence of a such an elasticity maximum in the case of the xanthan solution may be attributed to the significantly higher flexibility of the xanthan helix. A comparison of the critical concentrations calculated according to Flory's theory and the experimentally determined values shows that the two-phase region is distinctly broader than the theory predicts. This deviation cannot be attributed to the flexibility of the polymer, but can, however, be explained by intermolecular interactions. In contrast to the non-charged schizophyllan the polyelectrolyte xanthan is affected in addition to the attractive interactions (H-bonds) by electrostatic repulsion forces. [ABSTRACT FROM AUTHOR]

The effects of vitamin E (VE) on the liquid crystal behavior and structure of a lyotropic liquid crystal (LLC) system based on nonionic surfactant C 12 EO 10 /H 2 O are reported. Polarized optical microscopy, X-ray diffraction and FTIR combined with fluorescent analysis were utilized to study structural properties and the interactions between the vitamin E and hexagonal mesophase. It was revealed that up to 20 wt% VE is solubilized within the direct hexagonal mesophase. As a result, the lattice parameter and the melting point increased as compared with binary LLC C 12 EO 10 /H 2 O. The presence in the system C 12 EO 10 /H 2 O of VE in the amount above 30% (up to 60 wt%) leads to a structural transformation of the mesophase from the direct to reverse hexagonal mesophase. The structural changes of hydrophilic and hydrophobic domains in the presence of VE in LLC were characterized. [Display omitted] • Vitamin E was successfully incorporated into the С 12 EO 10 /H 2 O hexagonal phase. • The concentration limit of VE in the С 12 EO 10 /H 2 O/VE phase is up to 60 wt%. • A new method for detection of direct and reverse hexagonal phases has been suggested. • Lyotropic phase is a promising storage and release system for lipophilic biomolecules. [ABSTRACT FROM AUTHOR]