Cholesteric liquid crystals in living matter

Recently,a nu nprecedented observation of polar order,t hermochromic behavior,a nd exotic mesophases in new chiral, bent-shapeds ystemsw ith a ÀCH 3 moiety placed at the transverse position of the central core was reported. Herein,ah omologous series of compounds with even-numbered carbonc hains from n = 4t o1 8w ere synthesized, in which ÀCl was substituted for ÀCH 3 at the kink position and ad rastic modification in the phase structure of the bentshaped moleculew as observed. An unusuals tabilization of the cubic blue phase (BP) over aw ide range of 16.4 8Ch as been witnessed. Twoh omologues in this series (1-12 and 1-14) exhibit an interesting phase sequence consisting of BPI/ II, chiraln ematic, twist grain boundary,s mectic A, and smectic X( SmX) phases.T he higher homologues( 1-16 and 1-18) stabilizet he SmX phase enantiotropically over the entire temperature range. Crystal structure analysis confirmed the bent molecular architecture, with ab ent angle of 1488,a nd revealed the presenceo ft wo different molecular conformations in an asymmetric unit of compound 1-4. AD FT study corroborated that the ÀCl moiety at the central core of the molecule led to an increasei nt he dipole momenta long the transverse direction, which, in turn, facilitated the unusual stabilization of frustrated structures.C rystal polymorphism has been evidenced in three homologues( 1-10, 1-12, and 1-14) of the series. On the application of mechanical pressure through grinding, compound 1-10 transformedf rom a brighty ellow crystalline solid to ad ark orange-green amorphouss olid, which reversed upon dropwise additiono fd ichloromethane, indicating reversible mechanochromism in this class of compounds. In addition,e xcellent thermochromic behavior has been observed for compound 1-10w ith a controlled temperature-colorcombination.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.[a] Cr = crystal;I so = isotropic;N cyb * = chiral nematic phase composed of Sm clusters;T GBA = twist grain boundary phase;S mectic A = SmA; Smectic X = SmX. [b] Phaset ransitionso bserved by meanso fP OM in an ITO-coated planar cell (antiparallelrubbing). [c] Phase transitionso bserved by means of SAXS/WAXS.( 1-14: Cr 1a = amorphous,C r 2b = transition crystalline state, Cr 3c = crystal polymorph.)Chem.E ur.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chiral Bent‐Shaped Molecules Exhibiting Unusually Wide Range of Blue Liquid‐Crystalline Phases and Multistimuli‐Responsive Behavior

Punjani

Mohiuddin

Kaur

et al. 2020

“…[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] The critical role of LCs in living systemsh as been well recognized. [49][50][51] The significant contribution of LCs in contemporary nanoscience and nanotechnology is steadily becoming more noticeable. Liquid crystalline materialsh ave been classified into two broad classes:t hermotropic and lyotropic.…”

Section: Introductionmentioning

confidence: 99%

The Halogen Bond: An Emerging Supramolecular Tool in the Design of Functional Mesomorphic Materials

Wang

Bisoyi

Urbas

et al. 2018

Owing to their dynamic attributes, non-covalent supramolecular interactions have enabled a new paradigm in the design and fabrication of multifunctional material systems with programmable properties, performances, and reconfigurable traits. Recently, the "halogen bond" has become an enticing supramolecular synthetic tool that displays a plethora of promising and advantageous characteristics. Consequently, this versatile and dynamic non-covalent interaction has been extensively harnessed in various fields such as crystal engineering, self-assembly, materials science, polymer chemistry, biochemistry, medicinal chemistry and nanotechnology. In recent years, halogen bonding has emerged as a tunable supramolecular synthetic tool in the design of functional liquid-crystalline materials with adjustable phases and properties. In this Concept article, the use of halogen bond in the field of stimuli-responsive smart soft materials, that is, liquid crystals is discussed. The design, synthesis and characterization of molecular and macromolecular liquid crystalline materials are described and the modulation of their properties has been emphasized. The power of halogen bonding in offering a large variety of functional liquid crystalline materials from readily accessible mesomorphic and non-mesomorphic complementary building blocks is highlighted. The article concludes with a perspective on the challenges and opportunities in this emerging endeavor towards the realization of enabling and elegant dynamic functional materials.

“…In fact, cholesteric chitin causes the structural colour in beetles and determines their iridescence offering self‐defence strategies based on the reflected light by the exoskeleton structures. Moreover, cholesteric phases can be found when right handed helices of linear DNA are closely packed, forming a left‐handed chiral phase in a wide range of DNA concentrations …”

Section: Introductionmentioning

confidence: 99%

“…Moreover,c holesteric phases can be found when right handed heliceso fl inear DNA are closely packed, formingaleft-handedc hiral phase in aw ide range of DNA concentrations. [5] Only in the last years, evidence that many cells organize within biological tissues into well-aligned nematic domains, showinga lso their topological defects, has been also reported. Duringi nv itro experiments, different types of spindle-shape cells (e.g.…”

Section: Introductionmentioning

confidence: 99%

Advances in Cell Scaffolds for Tissue Engineering: The Value of Liquid Crystalline Elastomers

Martella

Parmeggiani

2018

Recent discoveries evidenced that many cells organize into well-aligned nematic domains, showing also their topological defects and suggesting the liquid crystalline order to be necessary for some biological functions. These evidences were described as the basis for the development of a new area of research in which polymeric liquid crystals were developed to exploit and promote cell adhesion and proliferation towards tissue regeneration. To address the requirements of tissue engineering, new biocompatible materials must be designed and synthesized to support cell adherence and growth together with nutrient transport under physiological condition. This Minireview presents a journey that, starting from the first discovery of liquid crystalline phases in biological (natural) materials with different structures and physical-chemical properties, will inform readers of the very recent application of liquid crystal polymeric materials as functional cell scaffolds to address current tissue engineering issues.