New bioconjugated amphiphilic mesogens with recognition groups have been synthesized, and their selfassembly behavior has been characterized at aqueous−liquid crystal (LC) interfaces. Specifically, the rod-shaped 2,3difluoro-4′-(4-trans-pentylcyclohexyl)biphenyl-based mesogen was conjugated with either biotin or the arginine−glycine− aspartic acid (RGD) peptide sequence through a tetraethylene glycol chain. Langmuir film measurements revealed that the two biorecognition moieties lead to very different surface pressure−area isotherms, indicating that biotin and RGD have distinct effects on self-assembled monolayers formed by these bioconjugated mesogens at aqueous surfaces. Measurements of the surface-induced orientations of LCs exhibited by biotin-conjugated mesogens mixed with the room-temperature nematic LC 4cyano-4′-pentylbiphenyl (5CB) revealed formation of cholesteric phases (consistent with the chiral nature of biotin) and evidence of the presence of the conjugated mesogen at aqueous interfaces. Preliminary measurements based on fluorescence measurements using Texas Red-labeled streptavidin confirmed that the biotin mesogen is located at the interface and capable of specific recognition of streptavidin. Overall, these results demonstrate that bioconjugated mesogens provide the basis of a general and facile method for the introduction of biological recognition functionality at aqueous−LC interface. These LC interfaces have mobility, elastic properties and responsiveness that are distinct from past studies of biorecognition groups presented at the interface of a solid or isotropic liquid, and the results thus provide a new approach for the introduction of biorecognition groups into this important and promising class of interface for biological and analytical applications.

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New liquid-crystalline (LC) gels composed of a lysine-based bisurea derivative having terminal acrylate moieties and a nematic liquid crystal, 4-cyano-4 0 -pentylbiphenyl, have been prepared to develop light-scattering electrooptical materials. Randomly dispersed networks of the polymerizable fibers are obtained by self-assembly of the lysine derivative through the formation of hydrogen bonds in the isotropic phase of the nematic LC molecule. After the isotropic-nematic transition of the LC molecule occurs at 35 1C on cooling, light-scattering nematic LC gels are formed because of the formation of microphase-separated structures of fibrous solids and the liquid crystal. The fibrous structures are fixed by photopolymerization, leading to the enhancement of thermal stability. The polymerized LC gels exhibit electrooptical switching between light-scattering and transparent states with lower driving voltages than the non-polymerized LC gels. The threshold voltages of the LC gels based on the polymerizable lysine gelator are also lower than those of the LC gels containing a non-polymerizable lysine gelator. Polymer Journal (2012) 44, 594-599; doi:10.1038/pj.2012.21; published online 21 March 2012Keywords: electrooptical properties; gel; gelator; hydrogen bond; liquid crystal; photopolymerization; self-assembly INTRODUCTION Liquid crystals have been widely used as electrooptical materials because their molecular alignment can be controlled by external electric fields. 1 Their electrooptical switching properties can be tuned by the incorporation of self-assembled fibers, 2-10 organic and inorganic particles, 11,12 and dendrimers 13 into liquid crystals as well as the encapsulation or phase separation of liquid crystals in polymer matrices. 14-16 Liquid-crystalline (LC) physical gels are formed by fibrous self-assembly of small amounts of gelators (0.2-5.0 wt%) in liquid crystals. [2][3][4][5][6][7][8][9][10] In these materials, the liquid crystals and the fibrous aggregates of the gelators form microphase-separated structures. The efficient electrooptical switching and the induction of light-scattering electrooptical effects of nematic liquid crystals were achieved by the formation of finely dispersed fibers of gelators in liquid crystals. [5][6][7][8][9] The electrooptical properties of the LC physical gels were examined for twisted nematic 5,6 and light-scattering modes. 7 To enhance thermal stability of the anisotropic gels, a new type of light-scattering LC gel has been developed by self-assembly of an L-valine-based gelator having methacryloyl moieties and a room temperature nematic liquid crystal. 10 The gelator formed randomly aligned fibrous aggregates through the formation of intermolecular hydrogen bonds in the isotropic phase of LC molecules. Photopolymerization of the gelator forming the self-assembled

Macroscopically oriented stable organic radicals have been obtained by using a liquid-crystalline (LC) gel composed of an l-isoleucine-based low molecular weight gelator containing a 2,2,6,6-tetramethylpiperidine 1-oxyl moiety. The LC gel has allowed magnetic measurements of the oriented organic radical. The gelator has formed fibrous aggregates in liquid crystals via intermolecular hydrogen bonds. The fibrous aggregates of the radical gelator are formed and oriented on cooling by applying a magnetic field to the mixture of liquid crystals and the gelator. Superconducting quantum interference device (SQUID) measurements have revealed that both oriented and nonoriented fibrous aggregates exhibited antiferromagnetic interactions, in which super-exchange interaction constant J is estimated as -0.89 cm(-1) .

We report a molecular dynamics (MD) simulation study of protein binding at the aqueous–liquid crystal (LC) interfaces of bioconjugated mesogenic molecules. As a simple model of these interfaces, we use monolayers composed of biotin-conjugated or biotin-free amphiphilic mesogenic molecules and streptavidin in water. The all-atom MD simulations reveal that the binding of streptavidin to the biotin mesogenic monolayer is significantly stronger than that to biotin-free mesogenic monolayers. Although specific protein binding marginally increases the overall orientational order and the tilt of the biotin-conjugated mesogenic molecules of the monolayer, significant changes in tilt were observed near the bound protein (in contrast to the protein interaction with the monolayer without biotin). We also observe that specific protein binding changes the dynamic properties of the mesogens within the monolayer (e.g., lateral diffusion coefficients) and associated water. Overall, these MD simulations advance our understanding of the molecular-level phenomena involved in the binding of biomolecules and subsequent dynamic changes at the aqueous–LC interfaces. These results provide guidance to future molecular-level designs of biofunctional LC interfaces.