Effect of the degree of protonation of amino acid dopants in Chirality amplification in DSCG Lyotropic Nematic phases.

Disodium Cromoglycate (DSCG), a lyotropic liquid crystal in water, is shown to be an amplifier of chirality when doped with small chiral molecules. Here, we study the behaviour of the DSCG nematic phase in the presence of three aminoacids with different degrees of protonation: L-Alanine, L-Arginine·HCl and L-Arginine. The results demonstrate that the sign of the helicity of the doped nematic phase (i.e., a cholesteric phase) depends on the sign of the Helical Twisting Power of the dopant.

Structures and topological defects in pressure-driven lyotropic chromonic liquid crystals

Lyotropic chromonic liquid crystals are water-based materials composed of self-assembled cylindrical aggregates. Their behavior under flow is poorly understood, and quantitatively resolving the optical retardance of the flowing liquid crystal has so far been limited by the imaging speed of current polarization-resolved imaging techniques. Here, we employ a single-shot quantitative polarization imaging method, termed polarized shearing interference microscopy, to quantify the spatial distribution and the dynamics of the structures emerging in nematic disodium cromoglycate solutions in a microfluidic channel. We show that pure-twist disclination loops nucleate in the bulk flow over a range of shear rates. These loops are elongated in the flow direction and exhibit a constant aspect ratio that is governed by the nonnegligible splay-bend anisotropy at the loop boundary. The size of the loops is set by the balance between nucleation forces and annihilation forces acting on the disclination. The fluctuations of the pure-twist disclination loops reflect the tumbling character of nematic disodium cromoglycate. Our study, including experiment, simulation, and scaling analysis, provides a comprehensive understanding of the structure and dynamics of pressure-driven lyotropic chromonic liquid crystals and might open new routes for using these materials to control assembly and flow of biological systems or particles in microfluidic devices.

Label-Free Detection and Spectrometrically Quantitative Analysis of the Cancer Biomarker CA125 Based on Lyotropic Chromonic Liquid Crystal

Compared with thermotropic liquid crystals (LCs), the biosensing potential of lyotropic chromonic liquid crystals (LCLCs), which are more biocompatible because of their hydrophilic nature, has scarcely been investigated. In this study, the nematic phase, a mesophase shared by both thermotropic LCs and LCLCs, of disodium cromoglycate (DSCG) was employed as the sensing mesogen in the LCLC-based biosensor. The biosensing platform was constructed so that the LCLC was homogeneously aligned by the planar anchoring strength of polyimide, but was disrupted in the presence of proteins such as bovine serum albumin (BSA) or the cancer biomarker CA125 captured by the anti-CA125 antibody, with the level of disturbance (and the optical signal thus produced) predominated by the amount of the analyte. The concentration- and wavelength-dependent optical response was analyzed by transmission spectrometry in the visible light spectrum with parallel or crossed polarizers. The concentration of CA125 can be quantified with spectrometrically derived parameters in a linear calibration curve. The limit of detection for both BSA and CA125 of the LCLC-based biosensor was superior or comparable to that of thermotropic LC-based biosensing techniques. Our results provide, to the best of our knowledge, the first evidence that LCLCs can be applied in spectrometrically quantitative biosensing.

Correction: Shear-induced polydomain structures of nematic lyotropic chromonic liquid crystal disodium cromoglycate

Correction for ‘Shear-induced polydomain structures of nematic lyotropic chromonic liquid crystal disodium cromoglycate’ by Hend Baza et al., Soft Matter, 2020, 16, 8565–8576.

Time Dependent Lyotropic Chromonic Textures in Microfluidic Confinements

Nematic and columnar phases of lyotropic chromonic liquid crystals (LCLCs) have been long studied for their fundamental and applied prospects in material science and medical diagnostics. LCLC phases represent different self-assembled states of disc-shaped molecules, held together by noncovalent interactions that lead to highly sensitive concentration and temperature dependent properties. Yet, microscale insights into confined LCLCs, specifically in the context of confinement geometry and surface properties, are lacking. Here, we report the emergence of time dependent textures in static disodium cromoglycate (DSCG) solutions, confined in PDMS-based microfluidic devices. We use a combination of soft lithography, surface characterization, and polarized optical imaging to generate and analyze the confinement-induced LCLC textures and demonstrate that over time, herringbone and spherulite textures emerge due to spontaneous nematic (N) to columnar M-phase transition, propagating from the LCLC-PDMS interface into the LCLC bulk. By varying the confinement geometry, anchoring conditions, and the initial DSCG concentration, we can systematically tune the temporal dynamics of the N- to M-phase transition and textural behavior of the confined LCLC. Overall, the time taken to change from nematic to the characteristic M-phase textures decreased as the confinement aspect ratio (width/depth) increased. For a given aspect ratio, the transition to the M-phase was generally faster in degenerate planar confinements, relative to the transition in homeotropic confinements. Since the static molecular states register the initial conditions for LC flows, the time dependent textures reported here suggest that the surface and confinement effects—even under static conditions—could be central in understanding the flow behavior of LCLCs and the associated transport properties of this versatile material.

Anti-allergic assessment of ethanol extractives of Quisqualis Indica Linn.

Aim:: The present work was aimed to find out the anti-allergic activity of ethanol extracts of Quisqualis indica Linn. (EEQI) by in-vitro and in-vivo murine models. Background:: Worldwide, the rise in prevalence of allergic diseases has continued in the industrialized world for more than 50 years. Worldwide, 0.05–2% of the population is estimated to experience anaphylaxis at some point in life. Quisqualis Indica Linn in an ornamental plant that have been rarely used as a herbal medicines, however presence of polyphenols and flavonoids have been reported to possessed anti-inflammatory, antipyretic and immunomodulatory activity which have some pathological relevance with anaphylaxis. Objective:: The objective of the present research was to investigate, scientifically explored and understand the probable antianaphylactic mechanism of ethanol extracts of Quisqualis indica Linn. via different preclinical models. Material and Method:: In-vitro study was done on de-granulated mesenteric mast cells induced by compound 48/80 and invivo study was done by passive cutaneous anaphylaxis (PCA) model. In the in-vitro study degranulated mesenteric cells were grouped into negative control (compound 48/80 treated), positive control (Disodium cromoglycate + 48/80 treated) and 3 test groups (EEQI 10 μg/ml + 48/80 treated, EEQI 50 μg/ml + 48/80 treated and EEQI 100 μg/ml + 48/80 treated). The number of degranulated mast cells was counted and compared within the different treatment groups. In the in-vivo study the rats were first grouped into negative control (vehicle only), positive control (Disodium cromoglycate) and 2 test groups (EEQI: 100 and 200 mg/kilogram). The animals were pretreated for 12 days. On the 12th day all the rats were immunized with serum anti-ovalbumin (obtained from an already sensitized rat) by the intradermal route. After 24 h of serum injection, Evans blue dye containing oval albumin was administered intravenously in all groups. Three days later, the rats were taken down for the severity of the anaphylactic reactions. Result:: EEQI significantly attenuate mast cell degranulation and maintain the cell intactness as compared to control (P < 0.001). It was set up to support the degree of anaphylaxis as compared to control group (P < 0.001). Conclusion:: The outcomes of the work revealed the preventive effect of Quisqualis indica Linn. against allergic manifestations.

DNA Origami Nano-Sheets and Nano-Rods Alter the Orientational Order in a Lyotropic Chromonic Liquid Crystal

Rod-like and sheet-like nano-particles made of desoxyribonucleic acid (DNA) fabricated by the DNA origami method (base sequence-controlled self-organized folding of DNA) are dispersed in a lyotropic chromonic liquid crystal made of an aqueous solution of disodium cromoglycate. The respective liquid crystalline nanodispersions are doped with a dichroic fluorescent dye and their orientational order parameter is studied by means of polarized fluorescence spectroscopy. The presence of the nano-particles is found to slightly reduce the orientational order parameter of the nematic mesophase. Nano-rods with a large length/width ratio tend to preserve the orientational order, while more compact stiff nano-rods and especially nano-sheets reduce the order parameter to a larger extent. In spite of the difference between the sizes of the DNA nano-particles and the rod-like columnar aggregates forming the liquid crystal, a similarity between the shapes of the former and the latter seems to be better compatible with the orientational order of the liquid crystal.

Shear-induced polydomain structures of nematic lyotropic chromonic liquid crystal disodium cromoglycate

Shear causes a lyotropic chromonic liquid crystal to tumble and to form a cascade of textural instabilities with polydomain director structures, disclinations and periodic stripes.