Showing papers on "Lyotropic liquid crystal published in 2018"
TL;DR: The continuum model, which couples structure and hydrodynamics, is able to capture the annihilation and movement of defects over long time scales, and is demonstrated to predict not only the static structure of the material, including its topological defects, but also the evolution of the system into dynamically arrested states.
Abstract: Achieving control and tunability of lyotropic materials has been a long-standing goal of liquid crystal research. Here we show that the elasticity of a liquid crystal system consisting of a dense suspension of semiflexible biopolymers can be manipulated over a relatively wide range of elastic moduli. Specifically, thin films of actin filaments are assembled at an oil-water interface. At sufficiently high concentrations, one observes the formation of a nematic phase riddled with [Formula: see text] topological defects, characteristic of a two-dimensional nematic system. As the average filament length increases, the defect morphology transitions from a U shape into a V shape, indicating the relative increase of the material's bend over splay modulus. Furthermore, through the sparse addition of rigid microtubule filaments, one can gain additional control over the liquid crystal's elasticity. We show how the material's bend constant can be raised linearly as a function of microtubule filament density, and present a simple means to extract absolute values of the elastic moduli from purely optical observations. Finally, we demonstrate that it is possible to predict not only the static structure of the material, including its topological defects, but also the evolution of the system into dynamically arrested states. Despite the nonequilibrium nature of the system, our continuum model, which couples structure and hydrodynamics, is able to capture the annihilation and movement of defects over long time scales. Thus, we have experimentally realized a lyotropic liquid crystal system that can be truly engineered, with tunable mechanical properties, and a theoretical framework to capture its structure, mechanics, and dynamics.
92 citations
TL;DR: A review of the characteristics of different structures of liquid crystalline phases, the influencing factors on the phase transition of liquid crystals and the relationship between structures of LLC and drug diffusion is given in this article.
Abstract: Lyotropic liquid crystals (LLCs) formed by the self-assembly of amphiphilic molecules in a solvent (usually water) have attracted increasingly greater attention in the last few decades, especially the lamellar phase (Lα), the reversed bicontinuous cubic phase (Q2) and the reversed hexagonal phase (H2). Such phases offer promising prospects for encapsulation of a wide range of target molecules with various sizes and polarities owing to the unique internal structures. Also, different structures of mesophases can give rise to different diffusion coefficients. The bicontinuous cubic phase and the hexagonal phase have been demonstrated to control and sustain the release of active molecules. Furthermore, the structures are susceptible to many factors such as water content, temperature, pH, the presence of additives etc. Many researchers have been studying these influencing factors in order to accurately fabricate the desired phase. In this paper, we give a review of the characteristics of different structures of liquid crystalline phases, the influencing factors on the phase transition of liquid crystals and the relationship between structures of LLC and drug diffusion. We hope our review will provide some insights into how to manipulate in a controlled manner the rate of incorporating and transferring molecules by altering the structure of lyotropic mesophases.
92 citations
TL;DR: Investigation of hydrated mixtures of the ionic surfactant tetramethylammonium decanoate loaded with 40 wt % n-decane revealed the formation of a high symmetry bicontinuous double diamond LLC, as well as cubic C15 and hexagonal C14 Laves LLC phases that mirror the MgCu2 and MgZn2 intermetallic structure types, respectively.
Abstract: Concentration-dependent supramolecular self-assembly of amphiphilic molecules in water furnishes a variety of nanostructured lyotropic liquid crystals (LLCs), which typically display high symmetry bicontinuous network and discontinuous micellar morphologies. Aqueous dispersions of soft spherical micelles derived from small molecule amphiphile hydration typically pack into exemplary body-centered cubic and closest-packed LLCs. However, investigations of hydrated mixtures of the ionic surfactant tetramethylammonium decanoate loaded with 40 wt % n-decane (TMADec-40) revealed the formation of a high symmetry bicontinuous double diamond LLC, as well as cubic C15 and hexagonal C14 Laves LLC phases that mirror the MgCu2 and MgZn2 intermetallic structure types, respectively. Detailed small-angle X-ray scattering analyses demonstrate that the complex C15 and C14 LLCs exhibit large unit cells, in which 12 or more ∼3–4 nm diameter micelles of multiple discrete sizes arrange into tetrahedral close packing arrangement...
67 citations
TL;DR: The effect of guest molecules on lipid-based LLC microstructures is reviewed, and different characterization methods are focused on, such as polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), self-diffusion nuclear magnetic resonance (SD-NMR), and so on.
Abstract: Liquid crystals (LCs) are conventionally divided into thermotropic or lyotropic, based on the organization and sequence of the controlled molecular system. Lipid-based lyotropic liquid crystal (LLC), such as lamellar (Lα), bicontinuous cubic (QII), or hexagonal (HII) phases, have attracted wide interest in the last few decades due to their practical potential in diverse applications and notable structural complexity. Various guest molecules, such as biopharmaceuticals, chemicals, and additives, can be solubilized in either aqueous or oily phase. And the LLC microstructure can be altered to affect the rate of drug release eventually. To utilize these microstructural variations to adjust the drug release in drug delivery system (DDS), it is crucial to understand the structure variations of the LLC caused by different types of guest molecules. Therefore, in this article, we review the effect of guest molecules on lipid-based LLC microstructures. In particular, we focus on the different characterization methods to evaluate this change caused by guest substances, such as polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), self-diffusion nuclear magnetic resonance (SD-NMR), and so on.
47 citations
01 Jan 2018
TL;DR: An overview of recent advances and current status of LLC nanoparticles, especially with respect to method of preparations, physichochemical characterizations, biopharmaceutical performance, and applications in the field of drug delivery for different therapeutic areas is given in this article.
Abstract: Lipid-based liquid crystalline nanoparticles have attracted great attention in the field of drug delivery. These systems consist of amphiphilic lipid molecules which self-assemble in aqueous environments to form complex three-dimensional structures. This complex structure can hold both hydrophilic and hydrophobic drugs and can release at different predetermined rates. The advent of lipid-based liquid nanocrystals or lyotropic liquid crystal (LLC) nanoparticles having highly ordered, thermodynamically stable, internal nanostructure has added a new dimension in formulation studies and has garnered a lot of interest amongst the scientific community. These novel lipidic systems have been proven for several advantages, such as multi-drug loading, high drug entrapment efficiency, potential for controlled and targeted release through functional modifications, reduced toxicity and biodegradable nature. This chapter gives an overview of recent advances and current status of LLC nanoparticles, especially with respect to method of preparations, physichochemical characterizations, biopharmaceutical performance, and applications in the field of drug delivery for different therapeutic areas. This review has focused in detail on the various phases of LLCs and potential materials of composition and their phase transition behavior with respect to various factors, knowledge of which would, in turn, help the reader in selecting the method of preparation and suitable characterization techniques. In addition, potential problems and possible future research directions for industrial scale-up and translation from bench to bed are highlighted.
40 citations
TL;DR: The current review article highlights some approaches towards the next generation surfactants, for example, those with catalytically active heads, and it is shown that amphiphilic properties can be obtained beyond the classical hydrophobic–hydrophilic interplay.
Abstract: Surfactants are ubiquitous in cellular membranes, detergents or as emulsification agents. Due to their amphiphilic properties, they cannot only mediate between two domains of very different solvent compatibility like water and organic but also show fascinating self-assembly features resulting in micelles, vesicles, or lyotropic liquid crystals. The current review article highlights some approaches towards the next generation surfactants, for example, those with catalytically active heads. Furthermore, it is shown that amphiphilic properties can be obtained beyond the classical hydrophobic-hydrophilic interplay, for instance with surfactants containing one molecular block with a special shape. Whereas, classical surfactants are static, researchers have become more interested in species that are able to change their properties depending on external triggers. The article discusses examples for surfactants sensitive to chemical (e.g., pH value) or physical triggers (temperature, electric and magnetic fields).
38 citations
TL;DR: In this paper, the spontaneous formation of lyotropic liquid crystals from the self-assembly of a series of minimalistic peptides is reported, where the highly charged peptides could self-assemble into rigid helical nanofilaments in water and spontaneously order into hexagonal liquid-crystalline phases with interfilament separations of ≤240 A.
Abstract: We report the spontaneous formation of lyotropic liquid crystals from the self-assembly of a series of minimalistic peptides. The highly charged peptides could self-assemble into rigid helical nanofilaments in water and spontaneously order into hexagonal liquid-crystalline phases with interfilament separations of ≤240 A. The formation of liquid crystals from the self-assembly of such simple peptides is dictated not only by the concentration and pH but also by the amino acid sequence of the peptides. Peptides containing the rigid Phe-Phe (FF) segment showed much higher propensities to form a liquid-crystalline phase with long-range order. Moreover, because of the intrinsic chirality of the peptides, the self-assembled birefringent liquid crystals could serve as sensing elements for the visual discrimination of chiral species and as templates for the biomimetic synthesis of mesoporous silica with ordered cavities. The results offer new opportunities for the design of peptide liquid crystals that are potenti...
33 citations
TL;DR: The formulation process was proved to influence strictly the physicochemical behavior of the prepared nanosystems, which presented colloidal stability over time and upon ionic strength increase, but they were affected by the presence of proteins and presented reversible structure alterations upon temperature increase.
32 citations
TL;DR: The water-driven self-assembly of homologous dianionic surfactants into lyotropic liquid crystals (LLCs) is investigated, with a focus on understanding how surfactant headgroup and counterion identities guide supramolecular spherical mesophase selection.
Abstract: The water-driven self-assembly of homologous dianionic surfactants into lyotropic liquid crystals (LLCs) is investigated, with a focus on understanding how surfactant headgroup and counterion identities guide supramolecular spherical mesophase selection Using temperature-dependent small-angle X-ray scattering (SAXS), we demonstrate that 2-alkylmalonate surfactants (CnMal-M2) with n = 8 (octyl) or 10 (decyl) and M = K+, Cs+, or (CH3)4N+ form both simple and complex micelle packings Observed spherical morphologies include body-centered cubic (BCC), hexagonally closest-packed (HCP), and tetrahedrally closest-packed Frank–Kasper (FK) A15 and σ phases (Pm3(−)n and P42/mnm symmetries, respectively) Previously observed in only one other minimally hydrated surfactant, the σ phase is a rare LLC morphology comprising a low-symmetry unit cell containing 30 sub-2-nm quasispherical micelles, each of which belongs to one of five symmetry-equivalent classes with discrete aggregation numbers Temperature versus water
31 citations
TL;DR: Hexagonal liquid crystal was considered as an effective delivery system for TCA and there was no significant difference in the anti‐inflammatory effects of TCA‐loaded hexagonal liquid Crystal and the commercially available product Voltaren® emulgel®.
25 citations
TL;DR: In this article, stimuli-responsive, superabsorbent materials are created by copolymerization of stimuliresponsive poly(n-isopropyl acrylamide) (PNIPAM) in combination with the superabsorent sodium acrylate (SA) via photopolymerization in lyotropic liquid crystal (LLC) templates.
TL;DR: In this paper, a gemini dicarboxylate surfactant self-assembles in water to form various aqueous LLC mesophases over a broad range of amphiphile concentrations, with an especially strong propensity to form the coveted double gyroid (GI) network mesophase.
Abstract: Nanoporous polymers with periodic, ordered structures have attracted significant interest for their potential applications as drug delivery vehicles, biomaterials, separations membranes, and materials for energy storage. Inducing polymer nanostructure through lyotropic liquid crystal-templated (LLC-templated) cross-linking photopolymerizations offers a promising means for morphological control at smaller length scales, which are difficult to access by other established strategies. We report the synthesis of a gemini dicarboxylate surfactant that self-assembles in water to form various aqueous LLC mesophases over a broad range of amphiphile concentrations, with an especially strong propensity to form the coveted bicontinuous double gyroid (GI) network mesophase. Aqueous GI LLCs surprisingly persist upon incorporation of as much as 10–37 wt % hexane-1,6-diol dimethacrylate (HDDMA) into the hydrophobic domains of these supramolecular surfactant assemblies, and cross-linking photopolymerization of the HDDMA u...
TL;DR: The micelles, hexagonal phase, bicontinuous cubic phase and lamellar phase were observed with the increase of CPBr concentration, and rich phase behaviours were due to the large cohesive energy densities of DESs.
Abstract: In recent years, aggregates formed in deep eutectic solvents (DESs), especially micelles, have attracted much attention. In this study, the phase behaviours of a cationic surfactant, cetylpyridinium bromide (CPBr), in two DESs, choline chloride + glycerol (ChG) and choline chloride + ethylene glycol (ChEG), were investigated in wide concentration and temperature ranges. With the help of small angle X-ray scattering, polarized optical microscopy and rheological measurements, the structures and properties of various aggregates were characterized. The micelles, hexagonal phase, bicontinuous cubic phase and lamellar phase were observed with the increase of CPBr concentration. Such rich phase behaviours were due to the large cohesive energy densities of DESs. Comparative studies in water and ethylammonium nitrate were carried out to explore how well DESs acted as self-assembly media.
TL;DR: A new way to size-selectively separate nanoparticles using lyotropic liquid crystals, in which nanoparticles smaller than a threshold size will be selectively transferred from the disordered phase into the ordered phase by tactoids during the phase separation process is indicated.
Abstract: Liquid crystalline tactoids are anisotropic microdroplets existing in isotropic phases. We studied the structure and evolution of tactoids in the presence of doping nanoparticles by electron microscopy at the resolution of individual mesogens and observed size-selective exclusion effects of liquid crystalline tactoids on foreign nanoparticles. We applied this principle to the separation of polymer nanospheres, gold nanoparticles, and magnetic nanoparticles by size. These results indicate a new way to size-selectively separate nanoparticles using lyotropic liquid crystals, in which nanoparticles smaller than a threshold size will be selectively transferred from the disordered phase into the ordered phase by tactoids during the phase separation process.
TL;DR: The nanoscratching platform can suggest a new nanofabrication way to make various electro-optical devices as well as other patterning applications and show versatility of the technique.
Abstract: A simple, fast, and cost-effective technique to obtain highly oriented thermotropic and lyotropic liquid crystal (LC) phases using a simple nanoscratching method is presented. Highly aligned linear nanogrooves are fabricated by scratching substrates such as normal, indium tin oxide (ITO), curved glasses, and ITO-coated polyethylene terephthalate (PET) film using diamond lapping films. To demonstrate the feasibility of the platform, typical thermotropic and lyotropic LC materials in the nematic phase are used to demonstrate the well-aligned domains along with the resulting scratched nanogrooves. The polarised optical microscopy (POM) images show excellent dark and bright states depending on the sample rotation, proving that the LC molecules are well aligned. The electro-optical performance of the twisted nematic (TN) mode LC display fabricated using the nanogrooves is also measured and indicates reliable results compared with that of the conventional device. Indeed, scratch-induced nanogrooves are well generated on the curved substrate and ITO-coated PET film to show versatility of our technique. Our platform can suggest a new nanofabrication way to make various electro-optical devices as well as other patterning applications.
TL;DR: Results show that 12-HOA is partly acting as co-surfactant, manifested by the destabilization of the hexagonal phase and the stabilization of the lamellar phase, which is substantially reduced in the surfactant solution compared to the system 12- HOA–n-decane.
Abstract: Gelled lyotropic liquid crystals can be formed by adding a gelator to a mixture of surfactant and solvent If the gel network and the liquid-crystalline phase coexist without influencing each other, the self-assembly is called orthogonal In this study, the influence of the organogelator 12-hydroxyoctadecanoic acid (12-HOA) on the lamellar and hexagonal liquid crystalline phases of the binary system H₂O⁻C12E₇ (heptaethylene glycol monododecyl ether) is investigated More precisely, we added 12-HOA at mass fractions from 0015 to 005 and studied the resulting phase diagram of the system H₂O⁻C12E₇ by visual observation of birefringence and by ²H NMR spectroscopy In addition, the dynamic shear moduli of the samples were measured in order to examine their gel character The results show that 12-HOA is partly acting as co-surfactant, manifested by the destabilization of the hexagonal phase and the stabilization of the lamellar phase The higher the total surfactant concentration, the more 12-HOA is incorporated in the surfactant layer Accordingly, its gelation capacity is substantially reduced in the surfactant solution compared to the system 12-HOA⁻n-decane, and large amounts of gelator are required for gels to form, especially in the lamellar phase
TL;DR: In this paper, the synthesis of lyotropic liquid crystalline phases using cetyl pyridinium chloride and sodium dodecyl sulphate in the aqueous (water) and non-aqueous solvent (glycerol) of varying polarity and viscosities is reported.
TL;DR: At high critical concentration, H2O2-hydrolyzed CHN colloids exhibited a sol-gel transition, which was discovered to be highly dependent on the storage time, concentration, temperature, and surface charge density.
TL;DR: This paper combines a cationic Gemini surfactant 12-3-12·2Br- and trans-2-methoxy-cinnamate ( trans-OMCA) together to create a representative UV-responsive self-assembly system and shows that the photoisomerization of OMCA from trans form to cis form under UV light irradiation alters the hydrophobicity and steric hindrance effect and thus affects the molecular packing at the micellar interface and further leads
Abstract: Photoresponsive systems with adjustable self-assembly morphologies and tunable rheological properties have aroused widespread concern of researchers in recent years because of their prospect applications in controlled release, microfluidics, sensors, and so forth. In this paper, we combine a cationic Gemini surfactant 12-3-12·2Br– and trans-2-methoxy-cinnamate (trans-OMCA) together to create a representative UV-responsive self-assembly system. The system displays abundant self-assembly behaviors, and the self-assemblies with different states and different scales including wormlike micelles, vesicles, and lyotropic liquid crystals (LCs) as well as an aqueous two-phase system (ATPS) are observed even at lower surfactant concentration. The UV-responsive behavior of the formed self-assemblies is investigated systematically. The results have shown that the photoisomerization of OMCA from trans form to cis form under UV light irradiation alters the hydrophobicity and steric hindrance effect of OMCA and thus aff...
TL;DR: Chimeric/mixed stimuli-responsive nanocarriers are promising agents for therapeutic and diagnostic applications, as well as in the combinatorial field of theranostics, and certain chimeric systems can be exploited as advanced drug delivery nanosystems, based on their overall promising profiles.
Abstract: Chimeric/mixed stimuli-responsive nanocarriers are promising agents for therapeutic and diagnostic applications, as well as in the combinatorial field of theranostics. Herein, we designed chimeric nanosystems, composed of natural phospholipid and pH-sensitive amphiphilic diblock copolymer, in different molar ratios and assessed the polymer lyotropic effect on their properties. Initially, polymer-grafted bilayers were evaluated for their thermotropic behavior by thermal analysis. Chimeric liposomes were prepared through thin-film hydration and the obtained vesicles were studied by light scattering techniques, to measure their physicochemical characteristics and colloidal stability, as well as by imaging techniques, to elucidate their global and membrane morphology. Finally, in vitro screening of the systems' toxicity was held. The copolymer effect on the membrane phase transition strongly depended on the pH of the surrounding environment. Chimeric nanoparticles were around and above 100 nm, while electron microscopy revealed occasional morphology diversity, probably affecting the toxicity of the systems. The latter was assessed to be tolerable, while dependent on the nanosystems' material concentration, polymer concentration, and polymer composition. All experiments suggested that the thermodynamic and biophysical properties of the nanosystems are copolymer-composition- and concentration-dependent, since different amounts of incorporated polymer would produce divergent effects on the lyotropic liquid crystal membrane. Certain chimeric systems can be exploited as advanced drug delivery nanosystems, based on their overall promising profiles.
TL;DR: The design and in-depth characterization of glycerol monooleate based liquid crystalline coatings on silicon wafers using drop casting and spin coating techniques are demonstrated and detailed insights into the formation and transformation of the coating nanostructures are provided.
Abstract: Functional coatings based on self-assembled lyotropic liquid crystals have the potential for applications such as biosensing, drug delivery and nanotemplating. Here we demonstrate the design and in-depth characterization of glycerol monooleate based liquid crystalline coatings on silicon wafers using drop casting and spin coating techniques. In situ time-resolved grazing incidence small angle X-ray scattering (GISAXS) measurements were used to monitor the coating formation and its response to increasing relative humidity conditions between 5 and 100%. Additional atomic force microscopy (AFM) measurements were applied to visualize the coating nanostructure. Structural transformations through ordered intermediate phases to the sponge- and lamellar phase were observed during ethanol evaporation. Relative humidity dependent GISAXS results revealed gradual phase transitions from the lamellar via the gyroid type cubic phase to the diamond type bicontinuous cubic structure between 5 and 100% relative humidity. The detailed insights into the formation and transformation of the coating nanostructures in this system may provide essential knowledge for the comprehensive design of functional nanostructured surfaces in biomedical applications.
TL;DR: An ordered, nanoporous, TEMPO-based polymer resin formed from lyotropic liquid crystal monomers catalyzes the hetereogeneous oxidation of alcohols with high activity and substrate size selectivity under transition-metal-free, aerobic conditions.
TL;DR: It is concluded that the polar-nonpolar interface of the inverse bicontinuous cubic phase of the phytantriol/water system is close to a parallel surface to a triply periodic minimal surface.
Abstract: We investigated two distinct lyotropic liquid crystal inverse bicontinuous cubic phases of phytantriol/water mixtures by small-angle X-ray crystallography of the single-crystal regions. Reconstructed electron density maps revealed hydrophilic head and hydrophobic tail regions of the phytantriol bilayer membranes and water regions. The bilayer membranes are shown to be located on the D and gyroid triply periodic minimal surfaces. To investigate the structures of the polar–nonpolar interfaces, we optimized two models: a parallel surface model and a constant mean curvature surface model. The parallel surface model agreed well with the X-ray data, and the R factors, which show the degree of agreement between those structural models and the data, were less than 0.04. In stark contrast, the constant mean curvature surface model deviated significantly from the data, and the R factors were around 0.15. We therefore conclude that the polar–nonpolar interface of the inverse bicontinuous cubic phase of the phytantri...
TL;DR: This paper demonstrates the production of nanowires using the HII phase in the phytantriol/water system which is obtained either by heating to 55 °C or at room temperature by the addition of a hydrophobic liquid, 9- cis-tricosene, to relieve packing frustration.
Abstract: We present an attractive method for the fabrication of long, straight, highly crystalline, ultrathin platinum nanowires. The fabrication is simply achieved using an inverse hexagonal (HII) lyotropic liquid crystal phase of the commercial surfactant phytantriol as a template. A platinum precursor dissolved within the cylindrical aqueous channels of the liquid crystal phase is chemically reduced by galvanic displacement using stainless steel. We demonstrate the production of nanowires using the HII phase in the phytantriol/water system which we obtain either by heating to 55 °C or at room temperature by the addition of a hydrophobic liquid, 9-cis-tricosene, to relieve packing frustration. The two sets of conditions produced high aspect nanowires with diameters of 2.5 and 1.7 nm, respectively, at least hundreds of nanometers in length, matching the size of the aqueous channels in which they grow. This versatile approach can be extended to produce highly uniform nanowires from a range of metals.
TL;DR: It is shown that in vitro, the DNA spatial structure is significantly changed in mesophases compared to non-organized DNA molecules, indicative of changes in major groove architecture.
Abstract: The anisotropic shape of DNA molecules allows them to form lyotropic liquid crystals (LCs) at high concentrations. This liquid crystalline arrangement is also found in vivo (e.g., in bacteriophage capsids, bacteria or human sperm nuclei). However, the role of DNA liquid crystalline organization in living organisms still remains an open question. Here we show that in vitro, the DNA spatial structure is significantly changed in mesophases compared to non-organized DNA molecules. DNA LCs were prepared from pBluescript SK (pBSK) plasmid DNA and investigated by photochemical analysis of structural transitions (PhAST). We reveal significant differences in the probability of UV-induced pyrimidine dimer photoproduct formation at multiple loci on the DNA indicative of changes in major groove architecture.
TL;DR: In this article, conditions to prepare cellulosic cholesteric liquid crystalline (ChLC) films in order to accomplish dual mechanochromism, i.e., colour control and circular dichroic inversion upon mechanical stimulus, at room temperature, were investigated.
Abstract: We investigated conditions to prepare cellulosic cholesteric liquid crystalline (ChLC) films in order to accomplish dual mechanochromism, i.e., colour control and circular dichroic inversion upon mechanical stimulus, at room temperature. Flexible propionylated hydroxypropyl cellulose (PHPC) was prepared by a simple reaction and found to be capable of forming lyotropic ChLC in various monomeric solvents. The ChLC solutions were subjected to in situ polymerization to obtain PHPC/synthetic polymer composite films incorporating the ChLC structure. However, the immobilization behaviour depended on the type of original monomers. Differential scanning calorimetry and solid-state NMR measurement revealed that the ChLC structure was more highly fixed when the compatibility between PHPC and the coexisting polymers was lower. Eventually, thus obtained ChLC composite films exhibited dual mechanochromism under ambient temperature.
TL;DR: Lyotropic liquid crystals, in which nanotubes coated with polyethylene glycol were aligned side-by-side in aqueous dispersions, acted as templates for the construction of surfactant-free gold nanorods with controllable diameters, functionalizable surfaces, and tunable optical properties.
TL;DR: In this paper, the formation of highly ordered lyotropic liquid crystalline phase of CdS nanoribbons of different length scales was observed, which showed the presence of long-range orientational order and positional order.
TL;DR: An artificial cerium-based proenzyme system that could be activated to a superoxide dismutase-like form using H2O2 as the trigger is proposed and opens up new possibilities for using nanoparticles as artificial proenzymes that are activated by a biochemical trigger in vivo.
Abstract: Inorganic nanoparticles that mimic the activity of enzymes are promising systems for biomedical applications. However, they cannot distinguish between healthy and damaged tissues, which could cause undesired effects. Natural enzymes avoid this drawback via activation triggered by specific biochemical events in the body. Inspired by this strategy, we proposed an artificial cerium-based proenzyme system that could be activated to a superoxide dismutase-like form using H2O2 as the trigger. To achieve this goal, an innovative and easy strategy to synthesize Ce(OH)3 nanoparticles as artificial proenzymes was developed using a lyotropic liquid crystal composed of phytantriol, which was essential to maintain their stability at physiological pH. The transmission electron microscopy measurements showed that the Ce(OH)3 nanoparticles were as small as 2 nm. The nanoparticles were fitted into the tiny aqueous channels of the liquid crystal matrix, which presented a Pn3m space group. X-ray absorption near edge structure measurements were used to determine the Ce(III) fraction of the proenzyme-like nanoparticles, which was around 85%. The Ce(III) fraction dramatically dropped to around 5% after contact with H2O2 because of the conversion of Ce(OH)3 to CeO(2−x) nanoparticles. The CeO(2−x) nanoparticles showed superoxide dismutase-like activity in contrast to the inactive Ce(OH)3 form. The proof of concept presented in this work opens up new possibilities for using nanoparticles as artificial proenzymes that are activated by a biochemical trigger in vivo.