Liquid crystal-based sensor for real-time detection of paraoxon pesticides based on acetylcholinesterase enzyme inhibition.

A liquid crystal-based assay (LC) was developed to monitor paraoxon by incorporating a Cu2+ -coated substrate and the inhibitory effect of paraoxon with acetylcholinesterase (AChE). We observed that thiocholine (TCh), a hydrolysate of AChE and acetylthiocholine (ATCh), interfered with the alignment of 5CB films through a reaction between Cu2+ ions and the thiol moiety of TCh. The catalytic activity of AChE was inhibited in the presence of paraoxon due to the irreversible interaction between TCh and paraoxon; consequently, no TCh molecule was available to interact with Cu2+ on the surface. This resulted in a homeotropic alignment of the liquid crystal. The proposed sensor platform sensitively quantified paraoxon with a detection limit of 2.20 ± 0.11 (n = 3) nM within a range of 6 to 500 nM. The specificity and reliability of the assay were verified by measuring paraoxon in the presence of various suspected interfering substances and spiked samples. As a result, the sensor based on LC can potentially be used as a screening tool for accurate evaluation of paraoxon and other organophosphorus compounds.

Lipidic lyotropic liquid crystals: Insights on biomedical applications.

Liquid crystals (LCs) possess unique physicochemical properties, translatable into a wide range of applications. To date, lipidic lyotropic LCs (LLCs) have been extensively explored in drug delivery and imaging owing to the capability to encapsulate and release payloads with different characteristics. The current landscape of lipidic LLCs in biomedical applications is provided in this review. Initially, the main properties, types, methods of fabrication and applications of LCs are showcased. Then, a comprehensive discussion of the main biomedical applications of lipidic LLCs accordingly to the application (drug and biomacromolecule delivery, tissue engineering and molecular imaging) and route of administration is examined. Further discussion of the main limitations and perspectives of lipidic LLCs in biomedical applications are also provided. STATEMENT OF SIGNIFICANCE: Liquid crystals (LCs) are those systems between a solid and liquid state that possess unique morphological and physicochemical properties, translatable into a wide range of biomedical applications. A short description of the properties of LCs, their types and manufacturing procedures is given to serve as a background to the topic. Then, the latest and most innovative research in the field of biomedicine is examined, specifically the areas of drug and biomacromolecule delivery, tissue engineering and molecular imaging. Finally, prospects of LCs in biomedicine are discussed to show future trends and perspectives that might be utilized. This article is an ampliation, improvement and actualization of our previous short forum article "Bringing lipidic lyotropic liquid crystal technology into biomedicine" published in TIPS.

Dominant Factors Affecting Rheological Properties of Cellulose Derivatives Forming Thermotropic Cholesteric Liquid Crystals with Visible Reflection.

Hydroxypropyl cellulose (HPC) derivatives with alkanoyl side chains are known to form thermotropic cholesteric liquid crystals (CLCs) with visible reflection. Although the widely investigated CLCs are requisite for tedious syntheses of chiral and mesogenic compounds from precious petroleum resources, the HPC derivatives easily prepared from biomass resources would contribute to the realization of environment-friendly CLC devices. In this study, we report the linear rheological behavior of thermotropic CLCs of HPC derivatives possessing alkanoyl side chains of different lengths. In addition, the HPC derivatives have been synthesized by the complete esterification of hydroxy groups in HPC. The master curves of these HPC derivatives were almost identical at reference temperatures, with their light reflection at 405 nm. The relaxation peaks appeared at an angular frequency of ~102 rad/s, suggesting the motion of the CLC helical axis. Moreover, the dominant factors affecting the rheological properties of HPC derivatives were strongly dependent on the CLC helical structures. Further, this study provides one of the most promising fabrication strategies for the highly oriented CLC helix by shearing force, which is indispensable to the development of advanced photonic devices with eco-friendliness.

Influence of the emulsifier on nanostructure and clinical application of liquid crystalline emulsions.

Liquid crystals are appealing in pharmaceutical and cosmetic fields due to their unique structures that combine the properties of both liquid and solid states. Forming an emulsion into liquid crystals can be affected by a number of factors, including the emulsion composition and temperature. Changing the types and concentrations of surfactants could be another factor that affects liquid crystals. Currently, most liquid crystal research focuses on the nanostructure of liquid crystal systems without evaluating the efficacy of liquid crystals clinically. In this study, liquid crystalline emulsions made from camellia seed oil with four different surfactants (Olivem 1000, Polyaquol-2W, Nikkomulese LC, and Lecinol S-10 with Tween 80) were created. The liquid crystal emulsions were formulated in the form of oil-in-water (o/w) emulsions with Camellia oleifera seed oil serving as the main ingredient in the oil phase (10% w/w). All formulations exhibited liquid crystal characteristics with lamellar structures as determined by the polarized light microscopy and small-angle X-ray scattering with supporting data of the nanostructure from wide-angle X-ray scattering and differential scanning calorimetry (DSC). They all showed good stability under normal (room temperature) and accelerated conditions (4 °C and 40 °C) in long-term storage (6 months). Using the reconstructed human epidermis as a skin model, all formulations did not cause skin irritation. In the clinical trial, all formulations were able to reduce transepidermal water loss (TEWL) and increase skin hydration immediately after application. This lasted at least 10 h. All formulations showed distinct Maltese crosses under the polarized light microscope with a positive result for liquid crystals in wide angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS) methods. Moreover, among all formulations tested, Formulation D, which contained Lecinol S-10 and Tween 80 as emulsifiers, showed the most robust interaction between the surfactant and water molecules in the lamellar structure under DSC. The formulation was stable in long-term normal and accelerated conditions. Above all, Formulation D, which was formulated with Lecinol S-10 with Tween 80, had the best clinical result, was nonirritating to the skin, and can be used as a cream base in the pharmaceutical and cosmeceutical sectors.

Percutaneous Penetration of Liquid Crystal Monomers (LCMs) by In Vitro Three-Dimensional Human Skin Equivalents: Possible Mechanisms and Implications for Human Dermal Exposure Risks.

Liquid crystal monomers (LCMs) are indispensable materials in liquid crystal displays, which have been recognized as emerging persistent, bioaccumulative, and toxic organic pollutants. Occupational and nonoccupational exposure risk assessment suggested that dermal exposure is the primary exposure route for LCMs. However, the bioavailability and possible mechanisms of dermal exposure to LCMs via skin absorption and penetration remain unclear. Herein, we used EpiKutis 3D-Human Skin Equivalents (3D-HSE) to quantitatively assess the percutaneous penetration of nine LCMs, which were detected in e-waste dismantling workers' hand wipes with high detection frequencies. LCMs with higher log Kow and greater molecular weight (MW) were more difficult to penetrate through the skin. Molecular docking results showed that ABCG2 (an efflux transporter) may be responsible for percutaneous penetration of LCMs. These results suggest that passive diffusion and active efflux transport may be involved in the penetration of LCMs across the skin barrier. Furthermore, the occupational dermal exposure risks evaluated based on the dermal absorption factor suggested the underestimation of the continuous LCMs' health risks via dermal previously.

Design of Liquid Crystal Materials Based on Palmitate, Oleate, and Linoleate Derivatives for Optoelectronic Applications.

Herein, liquid crystalline derivatives based on palmitate, oleate, and linoleate moieties with azomethine cores were synthesized, and their physical, chemical, optical, and photophysical properties were investigated in detail. The mesomorphic activity of these materials was examined through polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The observed results revealed that the stability of the thermal mesophase depends on the terminal polar as well as on the fatty long-chain substituents. Purely smectogenic phases were detected in all three terminal side chains. A eutectic composition with a low melting temperature and a broad smectic A range was found by constructing a binary phase diagram and addressing it in terms of the mesomorphic temperature range. The energy bandgap of the palmitate-based derivative (Ia) was determined as 3.95 eV and slightly increased to 4.01 eV and 4.05 eV for the oleate (Ib) and linoleate (Ic) derivatives, respectively. The optical constants (n, κ, εr, and εi) were extracted from the fitting of measured spectroscopic ellipsometer data. The steady-state spectra of these samples exhibited a broad emission in the range 400-580 nm, which was found to be blue shifted to 462 nm for both Ib and Ic derivatives. The average fluorescence decay lifetime of the Ia derivative was found to be 598 ps, which became faster for the Ib and Ic derivatives and slower for the sample with a chloride end polar group.

Phase Equilibria and Critical Behavior in Nematogenic MBBA-Isooctane Monotectic-Type Mixtures.

The transition from the isotropic (I) liquid to the nematic-type (N) uniaxial phase appearing as the consequence of the elongated geometry of elements seems to be a universal phenomenon for many types of suspensions, from solid nano-rods to biological particles based colloids. Rod-like thermotropic nematogenic liquid crystalline (LC) compounds and their mixtures with a molecular solvent (Sol) can be a significant reference for this category, enabling insights into universal features. The report presents studies in 4'-methoxybenzylidene-4-n-butylaniline (MBBA) and isooctane (Sol) mixtures, for which the monotectic-type phase diagram was found. There are two biphasic regions (i) for the low (TP1, isotropic liquid-nematic coexistence), and (ii) high (TP2, liquid-liquid coexistence) concentrations of isooctane. For both domains, biphasic coexistence curves' have been discussed and parameterized. For TP2 it is related to the order parameter and diameter tests. Notable is the anomalous mean-field type behavior near the critical consolute temperature. Regarding the isotropic liquid phase, critical opalescence has been detected above both biphasic regions. For TP2 it starts ca. 20 K above the critical consolute temperature. The nature of pretransitional fluctuations in the isotropic liquid phase was tested via nonlinear dielectric effect (NDE) measurements. It is classic (mean-field) above TP1 and non-classic above the TP2 domain. The long-standing problem regarding the non-critical background effect was solved to reach this result.

A Stable PDLC Film with High Ageing Resistance from an Optimized System Containing Rigid Monomer.

With the switchability between transparent and light-scattering states, polymer-dispersed liquid crystals (PDLC) are widely used as smart windows, flexible display devices, projectors, and other devices. In outdoor applications, in addition to excellent electro-optical properties, there is also a high demand for film stability. In this work, a PDLC film with high mechanical strength and structural stability is prepared that can maintain stability at 80 °C for 2000 h. By choosing liquid crystals with a wide temperature range, adopting acrylate polymer monomers containing hydroxyl groups, and adjusting the polymer content, the PDLC film can work well from -20 °C to 80 °C. On this basis, the effects of the introduction of rigid monomers on the mechanical properties and electro-optical properties of PDLC films are investigated.

Liquid Crystal@Nanosilver Catalytic Amplification-Aptamer Trimode Biosensor for Trace Pb2.

Liquid crystals (LCs) are a very important display material. However, the use of LC, especially LC-loaded nanoparticles, as a catalyst to amplify the analytical signal and coupled with specific aptamer (Apt) as a recognition element to construct a highly sensitive and selective three-mode molecular spectral assay is rarely reported. In this article, five LCs, such as cholesteryl benzoate (CB), were studied by molecular spectroscopy to indicate the liquid crystal nanoparticles in the system, and highly catalytic and stable CB loaded-nanosilver (CB@AgNPs) sol was prepared. The slope procedure was used to study the catalysis of the five LCs and CB@AgNPs on the new indicator reaction between AgNO3 and sodium formate (Fo) to produce silver nanoparticles (AgNPs) with a strong surface plasmon resonance absorption (Abs) peak at 450 nm, a resonance Rayleigh scattering (RRS) peak at 370 nm and a surface enhanced Raman scattering (SERS) peak at 1618 cm-1 in the presence of molecular probes. By coupling the new CB@AgNPs catalytic indicator reaction with the Apt reaction, a new CB@AgNPs catalytic amplification-SERS/RRS/Abs trimode biosensoring platform was constructed for detecting inorganic pollutants, such as Pb2+, Cd2+, Hg2+ and As3+.

Liquid Crystal Monomer: A Potential PPARγ Antagonist.

Liquid crystal monomers (LCMs) are a large family of artificial ingredients that have been widely used in global liquid crystal display (LCD) industries. As a major constituent in LCDs as well as the end products of e-waste dismantling, LCMs are of growing research interest with regard to their environmental occurrences and biochemical consequences. Many studies have analyzed LCMs in multiple environmental matrices, yet limited research has investigated the toxic effects upon exposure to them. In this study, we combined in silico simulation and in vitro assay validation along with omics integration analysis to achieve a comprehensive toxicity elucidation as well as a systematic mechanism interpretation of LCMs for the first time. Briefly, the high-throughput virtual screen and reporter gene assay revealed that peroxisome proliferator-activated receptor gamma (PPARγ) was significantly antagonized by certain LCMs. Besides, LCMs induced global metabolome and transcriptome dysregulation in HK2 cells. Notably, fatty acid ß-oxidation was conspicuously dysregulated, which might be mediated through multiple pathways (IL-17, TNF, and NF-kB), whereas the activation of AMPK and ligand-dependent PPARγ antagonism may play particularly important parts. This study illustrated LCMs as a potential PPARγ antagonist and explored their toxicological mode of action on the trans-omics level, which provided an insightful overview in future chemical risk assessment.

Research of Liquid-Crystal Materials for a High-Performance FFS-TFT Display.

A novel liquid-crystal compound of more than 99.95% purity with high performance (such as a high clearing point, large dielectric anisotropy, high optical anisotropy, low viscosity, and large elastic constants) was designed and synthesized according to the fringe-field switching thin-film-transistor-liquid-crystal display requirements (FFS-TFT). Then, a mixed liquid-crystal material suitable for an FFS-TFT display was developed by mixing this compound with other reported compounds, developing a product whose quality was that of the highest level of similar foreign products and which fully met the customer's use requirements (BOE), and thus able to completely replace similar imported materials.

Hybrid-Type Transparent Organic Light Emitting Diode with High Contrast Using Switchable Windows.

Transparent organic light emitting diode (OLED) display is one of the most promising devices among next-generation information displays because of beneficial characteristics, such as self-emissive and optically clear properties. Nevertheless, in conventional transparent OLED display devices, there are serious intrinsic problems in terms of the transmittance in the dark state because of empty windows in the cell, so the contrast ratio of the transparent OLED display would be deteriorated even though it can exhibit excellent bright state. In general, the transparent mode using the OLED device applies an empty area in each pixel because an emitting device could never reveal the background image, so the transparent OLED should contain the empty area in the pixel for transparent images. This may cause the optical degradation in the dark state. To solve this problem, we propose hybrid-type transparent OLED display modes that apply a liquid crystal (LC) to the transparent window part of the empty space. In this paper, we applied two dichroic LC modes- which use an electrically controlled birefringence (ECB) mode (Heilmeier type) for the polarized mode and a cholesteric LC mode (Guest-Host mode) for the non-polarized mode-to the empty area. In each hybrid mode, we have observed optical performance, including the transmittance in the dark/bright state, contrast ratio and response time as a function of cell parameters. As a result, we confirmed that the dark state and the contrast ratio could be improved by applying the proposed modes without serious decay of the transmittance in the bright state.

Theoretical Study of Charge Mobility in Crystal Porphine and a Computer Design of a Porphine-Based Semiconductive Discotic Liquid Mesophase.

Organic semiconductors are the focus of numerous studies; they are used in electronic devices. Modern research involves the production of neuromorphic organic materials, including those based on liquid crystal materials. The purpose of this work involves the theoretical modeling of molecules (the "core with branches" type) to construct a discotic mesophase capable of performing the functions of a neuromorphic material. For this purpose, the conductivity of crystal porphine, which can act as the nucleus of a molecule of the "core with branches" type, was investigated. The Marcus theory charge mobility values for the hole and electron were 0.148 and 0.088 cm2/V·s, respectively (the MOO method for calculating transfer integrals), and 0.561 and 0.160 cm2/V·s (DIPRO method). Based on TD-HF (HF-3c level of theory) calculations, possible structures of molecules for the formation of a discotic mesophase are proposed.

Automation of liquid crystal phase analysis for SAXS, including the rapid production of novel phase diagrams for SDS-water-PIL systems.

Lyotropic liquid crystal phases (LCPs) are widely studied for diverse applications, including protein crystallization and drug delivery. The structure and properties of LCPs vary widely depending on the composition, concentration, temperature, pH, and pressure. High-throughput structural characterization approaches, such as small-angle x-ray scattering (SAXS), are important to cover meaningfully large compositional spaces. However, high-throughput LCP phase analysis for SAXS data is currently lacking, particularly for patterns of multiphase mixtures. In this paper, we develop semi-automated software for high throughput LCP phase identification from SAXS data. We validate the accuracy and time-savings of this software on a total of 668 SAXS patterns for the LCPs of the amphiphile hexadecyltrimethylammonium bromide (CTAB) in 53 acidic or basic ionic liquid derived solvents, within a temperature range of 25-75 °C. The solvents were derived from stoichiometric ethylammonium nitrate (EAN) or ethanolammonium nitrate (EtAN) by adding water to vary the ionicity, and adding precursor ions of ethylamine, ethanolamine, and nitric acid to vary the pH. The thermal stability ranges and lattice parameters for CTAB-based LCPs obtained from the semi-automated analysis showed equivalent accuracy to manual analysis, the results of which were previously published. A time comparison of 40 CTAB systems demonstrated that the automated phase identification procedure was more than 20 times faster than manual analysis. Moreover, the high throughput identification procedure was also applied to 300 unpublished scattering patterns of sodium dodecyl-sulfate in the same EAN and EtAN based solvents in this study, to construct phase diagrams that exhibit phase transitions from micellar, to hexagonal, cubic, and lamellar LCPs. The accuracy and significantly low analysis time of the high throughput identification procedure validates a new, rapid, unrestricted analytical method for the determination of LCPs.

Paradigm of lyotropic liquid crystals in tissue regeneration.

The liquid crystalline phase has attracted tremendous attention from researchers across the globe due to its intriguing properties. In this article, we enumerate the different classes of liquid crystals. Lyotropic liquid crystals (LLCs) exhibit their liquid crystalline nature based on the surrounding solvent media, which opens novel horizons in drug delivery and tissue regeneration. The advantages of LLCs in the said fields and the thermodynamic mechanistic insights responsible for their structural stabilization have been conveyed. Various fabrication and characterization techniques, along with factors influencing the formation of LLCs, have been discussed. Applications in novel therapeutic avenues like bone extracellular matrix, cardiac remodeling, wound management, and implants have been unveiled. Also, regulatory considerations, patent, and clinical portfolios to circumvent the hurdles of clinical translation have been discussed. LLCs could be a promising approach in diverse avenues of tissue regeneration.

Bone ECM-inspired biomineralization chitin whisker liquid crystal hydrogels for bone regeneration.

As a particular cell niche, natural bone extracellular matrix (ECM) is an organic-inorganic composite material formed by mineralization of liquid crystal (LC) collagen fiber network. However, designing bone repair materials that highly imitate the LC characteristic and composite components of natural bone ECM is a great challenge. Here, we report a novel kind of bone ECM-inspired biomineralization chitin whisker LC hydrogels. First, photocurable chitin whisker LC hydrogels with bone ECM-like chiral nematic LC state and viscoelasticity are created. Next, biomineralization, guided by LC hydrogels, is carried out to truly mimic the mineralization process of natural bone, so as to obtain the organic-inorganic composite materials with bone ECM-like microenvironment. The chitin whisker LC hydrogels exhibit superior biomineralization, protein adsorption and osteogenesis ability, more importantly, LC hydrogel with negatively charged -COOH groups is more conducive to biomineralization and shows more desirable osteogenic activity than that with positively charged -NH2 groups. Notably, compared with the pristine LC hydrogels, the biomineralization LC hydrogels display more favorable osteogenesis ability due to their bone ECM-like LC texture and bone-like hydroxyapatite. This study opens an avenue toward the design of bone ECM-inspired biomineralization chitin whisker LC hydrogels for bone regeneration.

Forming, Confining, and Observing Microtubule-Based Active Nematics.

The formation of biopolymer-based active phases has become an important technique for researchers interested in exploring the emerging field of active liquid crystals and their possible roles in cell biology. These novel systems consist of self-driven sub-units that consume energy locally, producing an out-of-equilibrium dynamic fluid. To form the active liquid crystal phase described in this report, purified protein components including biopolymers and molecular motors are combined, and the active nematic phase spontaneously forms in the presence of adenosine triphosphate (ATP). To observe the nematic state, the material must be confined in a suitable geometry for microscopy at a high enough density. This article describes two different methods for the formation of an active nematic phase using microtubules and kinesin motors: assembly of a two-dimensional active layer at an oil and water interface and assembly under an oil layer using an elastomeric well. Techniques to insert the active material into small wells of different shapes are also described.

Functional Liquid Crystal Core/Hydrogel Shell Microcapsules for Monitoring Live Cells in a 3D Microenvironment.

Three-dimensional (3D) cell culture, even as a simple microspheroid model, can be used to recapitulate the native biological microenvironment of cells. Examining the biochemical characteristics of cells in multicellular hydrogel microspheroids using microsensors is usually limited to monitoring the medium around the microspheroids. Here, functional liquid crystal (LC) core/hydrogel shell microcapsules loaded with cells were prepared using droplet microfluidic technology for monitoring live cells in a 3D microenvironment. These microcapsules have a distinctive core/shell structure; cells can be cultured in the hydrogel shell of this 3D model. The functional LC core responds to the acidic microenvironment of cells, showing an axial-to-bipolar transfiguration. 3D cell culture and visual monitoring of the cell microenvironment can be simultaneously achieved in a single microcapsule. Therefore, this novel method may enable a standard approach for monitoring multiple ions or molecules in a 3D model of the cell microenvironment.

Dynamic grass color scale display technique based on grass length for green landscape-friendly animation display.

Public displays, such as liquid crystal displays (LCDs), are often used in urban green spaces. However, these display devices often tarnish the green landscape of urban green spaces due to their artificial materials. We previously proposed a green landscape-friendly grass animation display that dynamically controls the grass color pixel by pixel. The grass color is changed by moving a green grass length in yellow grass, and the grass animation display runs simple animations using grayscale images. In our previous study, the color scale is subjectively mapped to the green grass length. However, this method fails to display the grass colors corresponding to the color scale based on objective evaluations. Herein, we introduce a dynamic grass color scale display technique based on the grass length. We develop a grass color scale setting procedure to map the grass length to the five-level color scale through image processing. In the outdoor experiment of the grass color scale setting procedure, the color scale corresponds to the green grass length based on a viewpoint. Finally, we demonstrate a grass animation display to show the animations with the color scale using experimental results.

Remote Loading of Hydrophilic Drug into Cubosomes by Transmembrane pH-Gradient and Characterization of Drug-Loaded Cubosomes Prepared by Different Method.

The encapsulation efficiency (EE) of hydrophobic drug into cubosomes was high by conventional methods, while poor for the hydrophilic drug. In this study, a remote loading method based on transmembrane pH-gradient was applied to prepare hydrophilic drug loaded cubosomes. Several hydrophilic drugs were selected and studied. Results showed just part of the investigated drugs were successfully loaded into cubosomes by the remote loading method, whereas all the drugs failed to be encapsulated by the high-pressure homogenization method. The EE based on remote loading method was affected by the solubility, LogP, number of rings, and polarizability of the drug independent of the number of hydrogen acceptor and hydrogen donor. And the drugs that had high EE by remote loading method were BCS class 1 or 2. In addition, the EE base on remote loading method was significantly affected by the external water pH of cubosomes and drug concentration. The size of drug-loaded cubosomes by remote loading method mainly depended on the pre-formed blank cubosomes, which was bigger than that by high-pressure homogenization method. The preparation method affected the liquid crystalline structure of acidic drug loaded cubosomes, while showed no obvious effect on that of basic drug loaded cubosomes. The release of drug was susceptible to the pH of release medium independent of the preparation method. The drug-loaded cubosomes prepared by different method all showed favorable stability during storage. The remote loading method was a promising approach for the efficient encapsulation of hydrophilic drug into cubosomes. This study laid a foundation for the application of remote loading method on the preparation of hydrophilic drug loaded cubosomes.