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Photonic solid-state cholesteric liquid crystal (CLC solid ) droplets intertwined with a poly(acrylic acid) (PAA) network that has an interpenetrating polymer network (IPN) structure (referred to as photonic IPN CLC solid-PAA droplets) were used as individual sensors in the dots of a PAA-patterned array film after functionalization via immobilization of the receptors and a metal-ion treatment. The photonic IPN CLC solid-PAA droplets in the PAA-patterned array film were pH-responsive and showed an observable change in the reflected central color. This "smart" property, coupled with the photonic color response, makes these devices ideal photonic sensors. The immobilization of urease and phenylboronic acid on the PAA network allowed for the application of several 10 μm photonic IPN CLC solid-PAA droplets to the optical photonic biosensors through facilitated volumetric changes in the PAA network in response to urea and glucose analytes, with high selectivity for major components in human serum, acceptable sensitivity for use with human serum, and extreme stability due to a solid-state structure. The blueshift of the reflected color of the KOH-treated photonic IPN CLC solid-PAA droplets could be used for divalent metal-ion detection. The compartmentalized photonic IPN CLC solid-PAA droplets in the patterned array film could be used for multiple detection applications, as evidenced by the ability to conduct pH, divalent metal ion, urea, and glucose detections in one patterned array film. This new platform opens the door for many interesting applications with numerous combinations of responsive hydrogel matrices and receptors.

A glucose biosensor was developed based on a 4-cyano-4'-pentylbiphenyl (5CB)-filled transmission electron microscopy (TEM) grid cell by coating poly (styrene-b-acrylic acid) (PS-b-PAA) at the 5CB/aqueous interface and immobilising 3-aminophenyl boronic acid (APBA) on the PAA block chains by N-(3-dimethylaminopropyl)-N-ethylcarbodiimide coupling. Binding events between APBA and glucose were translated into homeotropic-to-planar configurational changes of 5CB, which were observed by polarised optical microscopy (POM) under crossed polarisers. This liquid-crystal-based glucose biosensor exhibited high sensitivity (limit of detection: 0.1 mM), even in complex serum and urine samples, high selectivity (against cholesterol, haemoglobin, and urea), and good stability for 40 d. This new and sensitive glucose biosensor has the advantages of low production cost, a simple immobilisation technique, and easy detection with POM, and may be useful for pre-screening glucose levels in human samples (serum and urine)., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A simple and easy to handle biosensing technique for in vitro detection of HSA-DNP antigen induced allergen reactions in patients has been developed through the detection of sensitized basophils expressed with anti-IgE receptor (FcεRI) by using human serum albumin-dinitrophenol (HSA-DNP) antigen-anchored liquid crystal (LC) microdroplets emulsion. The radial to bipolar transition in nematic 4-cyano-4'-pentyl biphenyl liquid crystal molecules (5CB) confined in HSA-DNP antigen anchored LC microdroplets (8.5 pg HSA-DNP/LC microdroplet) is found to be sensitive in PBS solution in detection of allergen sensitized basophils expressed with a minimum amount of anti HSA-DNP (anti-IgE) receptor (≥4.5 pg/basophil). The detection of allergen sensitized basophils was possible within a contact time of 30 min in presence of control cells and with 10% solution of human blood plasma. The HSA-DNP antigen anchored LC microdroplets in presence of macrophages or non-sensitized basophils did not show radial to bipolar transition in 5CB molecules in PBS or solution with 10 wt% human blood plasma. Thus HSA-DNP antigen anchored LC microdroplets biosensor may be used for in vivo detection of stage I allergen reaction basophils in blood samples., (Copyright © 2018 Elsevier Inc. All rights reserved.)

We developed a new technology that uses backscattering interferometry (BSI) to quantitatively measure nematic liquid crystal (NLC)-based biosensors, those usually relied on texture reading for on/off signals. The LC-based BSI comprised an octadecyltrichlorosilane (OTS)-coated square capillary filled with 4-cyano-4'-pentylbiphenyl (5CB, a nematic LC at room temperature). The LC/water interface in the capillary was functionalized by a coating of poly(acrylicacid-b-4-cyanobiphenyl-4'-oxyundecylacrylate) (PAA-b-LCP) and immobilized with the enzymes glucose oxidase (GOx) and horseradish peroxidase (HRP) through covalent linkage to the PAA chains (5CB PAA-GOx:HRP ) for glucose detection. Laser irradiation of the LC near the LC/water interface resulted in backscattered fringes with high contrast. The change in the spatial position of the fringes (because of the change in the orientation of the LC caused by the GOx:HRP enzymatic reaction of glucose) altered the output voltage of the photodetector when its active area was aligned with the edge of one of the fringes. The change in the intensity at the photodetector allowed the detection limit of the instrument to be as low as 0.008mM with a linear range of 0.02-9mM in a short response time (~60s). This LC-based BSI technique allows for quantitative, sensitive, selective, reproducible, easily obtainable, and interference-free detection in a large linear dynamic range and for practical applications with human serum., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The present study utilizes antibody-protein interactions to develop an LC microdroplet based biosensor for naked eye detection of SK-BR3 human breast cancer cells. The herceptin antibody-conjugated LC microdroplets were fabricated using 4-cyano-4'-pentyl biphenyl (5CB) as the liquid crystalline phase and sodium dodecyl sulfate (SDS) as the surfactant. The poly (styrene-b-acrylic acid) amphiphilic block copolymer (PS-b-PA) played a role as a modifier for the liquid crystalline interfaces. The 5CB molecules in the herceptin antibody-conjugated LC microdroplets have shown an orientation transition from radial to bipolar on selective interactions with targeted SK-BR3 breast cancer cells, which are over expressed by the human epidermal growth factor receptor 2-positive (HER2). The herceptin antibody-conjugated LC microdroplets are found to be highly selective in the detection of SK-BR3 cancer cells in the presence of control cells, such as KB cancer cells and fibroblast (FB), and also in the presence of 10% human blood plasma. The interaction forces of the SK-BR3 cancer cells were only effective in causing orientation transitions in 5CB molecules in the LC microdroplets, which clearly suggested that the herceptin antibody-conjugated LC microdroplets could be used as a selective biosensor for a real-time detection of SK-BR3 cancer cells in biological fluids.

By utilizing a microfluidics approach, we prepared uniformly sized cholesteric liquid crystal (CLC) droplets from MLC-2132 doped with a chiral dopant (S)-4-cyano-4'-(2-methylbutyl)biphenyl (CB15). We studied the helical structures and reflecting color patterns of high- and low-dopant CLC droplets coated with poly(vinyl alcohol) (PVA) and sodium dodecyl sulfate (SDS). One central large spot with reflecting color in the CLC droplets (initially coated with PVA for planar anchoring) changed to many small spots with the same reflecting color (chicken-skin pattern) when an SDS aqueous solution was introduced to increase the homeotropic anchoring power. These small spots subsequently merged into several spots (flashlight pattern) with time. The CLC droplets coated with poly(acrylic acid)-b-poly(4-cyanobiphenyl-4'-oxyundecyl acrylate) (PAA-b-LCP) (CLC PAA droplets) were pH-responsive. Their helical structure and the reflecting color pattern changed because of protonation (at low pH) and deprotonation (at high pH) of the carboxylic group of PAA, which causes the planar (tangential) and perpendicular (homeotropic) orientations, respectively. The CLC PAA droplets immobilized with glucose oxidase (GOx) and cholesterol oxidase (ChO) (CLC PAA-GOx and CLC PAA-ChO droplets, respectively), for glucose and cholesterol detection, exhibited high sensitivity (0.5 and 2.5 μM for the CLC PAA-GOx and CLC PAA-ChO droplets, respectively), good selectivity, and fast response (≤4 s). Further optimization will enhance their performance as biosensors. With this novel approach, detection is possible by observing the coloring pattern of CLC droplets, without the crossed polarizers that are necessary for nematic LC biosensor systems.

A liquid-crystal (LC)-filled transmission electron microscopy (TEM) grid cell coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB), to which a single-stranded deoxyribonucleic acid probe (ssDNAprobe) was adsorbed at the LC/aqueous interface (TEMDTAB/DNA), was applied for the highly specific detection of target DNA molecules. The DTAB-coated E7 (used LC mixture) in the TEM grid (TEMDTAB) exhibited a homeotropic orientation, and changed to a planar orientation upon adsorption of the ssDNAprobe. The TEMDTAB/DNA was then exposed to complementary (target) ssDNA, which resulted in a planar-to-homeotropic configurational change of E7 that could be observed through a polarized optical microscope under crossed polarizers. The optimum adsorption density (2 μM) of ssDNAprobe enabled the detection of ≥0.05 nM complementary ssDNA. This TEMDTAB/DNA biosensor could differentiate complementary ssDNA from mismatched ssDNA as well as double-stranded DNA. It also successfully detected the genomic DNAs of the bacterium Erwinia carotovora and the fungi Rhazictonia solani. Owe to the high specificity, sensitivity, and label-free detection, this biosensor may broaden the applications of LC-based biosensors to pathogen detection.

Glucose oxidase (GOx) and horseradish peroxidase (HRP) were co-immobilized to the polyacrylicacid block of a poly(acrylicacid-b-4-cyanobiphenyl-4'-undecylacrylate) (PAA-b-LCP) copolymer in water. PAA-b-LCP was strongly anchored by the LCP block in 4-cyano-4'-pentylbiphenyl (5CB) which was contained in a transmission electron microscope (TEM) grid for glucose detection. The optimal conditions for the performance of the TEM grid glucose biosensor were studied in terms of the activity and stability of the immobilized enzymes. Glucose in water was detected by the 5CB changing from a planar to a homeotropic orientation, as observed through a polarized optical microscope. The TEM biosensor detected glucose concentrations at ⩾0.02 mM, with an optimal GOx/HRP molar ratio of 3/1. This glucose biosensor has characteristics of enzyme sensitivity and stability, reusability, the ease and selective glucose detection which may provide a new way of detecting glucose., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Sodium dodecyl sulphate (SDS) including β-cyclodextrin (β-CD) (β-CDSDS) was used to detect cholesterol at the 4-cyano-4'-pentylbiphenyl (5CB)/aqueous interface in transmission electron microscopy (TEM) grid cells. The β-CD acts as a host for SDS (guest). The guest SDS enclosed within the β-CD cavity was replaced with cholesterol by injecting cholesterol solution into the TEM cell at concentrations greater than 3 μM. The replacement of SDS with cholesterol was confirmed by pH measurement and high performance liquid chromatography (HPLC). The SDS excluded from the β-CD altered the planar orientation of the 5CB confined within the TEM grid cell to a homeotropic orientation. This planar-to-homeotropic transition was observed using a polarized optical microscope under crossed polarizers. This convenient TEM grid cell provides a new method for the selective detection of cholesterol without immobilization of the detecting receptors (enzyme, antibody, or aptamer) or the use of sophisticated instruments., (Copyright © 2015 Elsevier B.V. All rights reserved.)

4-Cyano-4'-pentylbiphenyl (5CB) in a transmission electron microscopy (TEM) grid was developed for glucose detection by coating with a monolayer of mixed polymer brushes using poly(acrylicacid-b-4-cynobiphenyl-4'-oxyundecylacrylate) (PAA-b-LCP) and quaternized poly(4-vinylpyridine-b-4-cynobiphenyl-4'-oxyundecylacrylate) (QP4VP-b-LCP) (LCP stands for liquid crystal polymer) at the 5CB/aqueous interface. The resultant 5CB in TEM grid was functionalized with the PAA and QP4VP brushes, which were strongly anchored by the LCP block. The PAA brush rendered the 5CB/aqueous interface pH-responsive and the QP4VP brush immobilized glucose oxidase (GOx) through electrostatic interactions without the aid of coupling agents. The glucose was detected through a homeotropic-to-planar orientational transition of the 5CB observed through a polarized optical microscope (POM) under crossed polarizers. The optimum immobilization with a 0.78 µM GOx solution on the dual-brush-coated TEM grid enabled glucose detection at concentrations higher than 0.5 mM with response times shorter than 180 s. This TEM grid glucose sensor provided a linear response of birefringence of the 5CB to glucose concentrations ranging from 0.5 to 11 mM with a Michaelis-Menten constant (Km) of 1.67 mM. This new and sensitive glucose biosensor has the advantages of low production cost, simple enzyme immobilization, high enzyme sensitivity and stability, and easy detection with POM, and may be useful for prescreening the glucose level in the human body., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Poly(acrylicacid-b-4-cynobiphenyl-4'-undecylacrylate) (PAA-b-LCP)-functionalized 4-cyano-4'-pentylbiphenyl (5CB) droplets were made by using microfluidic technique. The PAA chains on the 5CB droplets, were biotinylated, and used to specifically detect avidin-biotin binding at the 5CB/aqueous interface. The avidin-biotin binding was characterized by the configurational change (from radial to bipolar) of the 5CB droplets, as observed through a polarized optical microscope. The maximum biotinylation was obtained by injecting a >100 μg/mL biotin aqueous solution, which enabled a limit of detection of 0.5 μg/mL avidin. This droplet biosensor could specifically detect avidin against other proteins such as bovine serum albumin, lysozyme, hemoglobin, and chymotrypsinogen solutions. Avidin detection with 5CBPAA-biotin droplets having high sensitivity, specificity, and stability demonstrates new applications of the functionalized liquid crystal droplets that can detect specific proteins or other analytes through a ligand/receptor model., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A KB cancer cell-selective, liquid crystal microdroplets emulsion is prepared using folic acid-conjugated block copolymers (PS-b-PAA-FA) and sodium dodecyl sulfate (SDS) as a mediator to induce configurational transitions in 4-cyano-4'-pentylbiphenyl (5CB) liquid crystal microdroplets emulsion. The prepared liquid crystal microdroplets emulsion has shown a configurational transition from radial to bipolar on interacting with KB cancer cells, but no transition from radial to bipolar configuration is observed when liquid crystal microdroplets emulsion was allowed to interact with other normal cells such as fibroblast and osteoblast. The KB cancer cell selectivity of liquid crystal microdroplets emulsion has been considered due to the presence of KB cancer cell folate receptor-specific ligand (FA) at the surface of liquid crystal microdroplets, which allowed liquid crystal microdroplets to interact specifically with KB cancer cells. The ligand-receptor interactions have been considered responsible for triggering the configurational transitions from radial to bipolar in liquid crystal microdroplets emulsion. Thus, folate ligand anchored liquid crystal microdroplets emulsion has shown a potential to be used for in vitro detection of KB cancer cells in the early stage of tumor development.

The interface between nematic liquid crystal, 4-cyano-4'-pentylbiphenyl (5CB), and water in a transmission electron microscopy (TEM) grid cell coated with QP4VP-b-LCP (quaternized poly(4-vinylpyridine) (QP4VP) and poly(4-cyanobiphenyl-4'-oxyundecylacrylate) (LCP)) was examined for protein and DNA detection. QP4VP-b-LCP was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Quaternization of P4VP with iodomethane (CH3I) made it a strong cationic polyelectrolyte and allowed QP4VP-b-LCP to form complexes with oppositely charged biological species. Several proteins, such as bovine serum albumin (BSA), hemoglobin (Hb), α chymotrypsinogen-A (ChTg), and lysozyme (LYZ), were tested for nonspecific protein detection. By injecting the protein solutions into the TEM grid cell, the initial homeotropic orientation of the TEM grid cell changed to a planar orientation above their isoelectric points (PIs) due to electrostatic interactions between QP4VP (+charge) and proteins (-charge), which did not occur below the PIs of the tested proteins. Their minimum concentrations at which the homeotropic to planar configurational change (H-P change) occurred were 0.01, 0.02, 0.03, and 0.04 wt.% for BSA, ChTg, Hb, and LYZ, respectively. One of the strong anionic polyelectrolytes, deoxyribonucleic acid (DNA) (due to the phosphate deoxyribose backbone) was also tested. A H-P change was observed with as little as 0.0013 wt.% salmon sperm DNA regardless of the pH of the cell. A H-P change occurred in 5CB and was observed by polarized optical microscopy. This simple and inexpensive setup for nonspecific biomaterial detection provides the basic idea for developing effective selective biosensors by introducing specific binding groups, such as the aptamer and antibody.

The interface between the nematic liquid crystal, 4-cyano-4'-pentylbiphenyl (5CB) and water within a transmission electron microscopy (TEM) grid cell coated with the pH-dependent weak cationic amphiphilic block copolymer poly((4-cyanobiphenyl-4'-oxyundecylacrylate)-b-((2-dimethyl amino) ethyl methacrylate)) (LCP-b-PDMAEMA) (which was successfully synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization) was subsequently evaluated for protein and deoxyribonucleic acid (DNA) detection. The LCP-b-PDMAEMA monolayer was fabricated using a Langmuir Blodgett trough, transferred to the 5CB-filled TEM grid, and placed on the octadecyltrichlorosilane-coated glass (TEMPDMAEMA) in such a way that the LCP chains were immersed in the 5CB while the PDMAEMA chains were pointed away from the 5CB surface and immersed in water. Several model proteins such as bovine serum albumin (BSA), hemoglobin (Hb), and chymotrypsinogen (ChTg) were tested at pH values ranging from 2 to 12 to determine the role of the charge state of the protein on protein detection by a weak polyelectrolyte such as PDMAEMA. PDMAEMA contains cationic and neutral states below and above the pKa value, respectively, and is thus able to absorb proteins below its pKa threshold through electrostatic interactions. BSA exhibited a homeotropic to planar (H-P) change in orientation within the TEMPDMAEMA grid cell at concentrations greater than 0.02wt% within the pH range between the isoelectric point (pI) of BSA and the pKa of PDMAEMA, where the charge states of BSA and PDMAEMA were negative and positive, respectively. However, this change in orientation did not occur with other proteins that exhibited a pI higher than the pKa of PDMAEMA due to the electrostatic repulsions resulting from their same cationic charges. This result indicates that the electrostatic interactions between proteins and PDMAEMA are a major contributing factor for protein detection by the H-P transformation within the TEMPDMAEMA grid cell. DNA, a pH-independent strong anionic polyelectrolyte, was also tested with the TEMPDMAEMA grid cell, and it exhibited an H-P transformation at the charged state of PDMAEMA below its pKa threshold at concentrations higher than 0.01wt%. Thus, we demonstrated that the TEMPDMAEMA grid cell effectively facilitated the detection of negatively charged biomaterials (i.e.; protein and DNA) through the H-P transformation using the polarized optical microscope. This simple and inexpensive experimental set-up for non-specific biomaterial detection lays the basic groundwork for developing effective biosensors using polyelectrolytes., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A transmission electron microscopy (TEM) grid filled with 4-cyno-4-pentylbiphenyl (5CB) on the octadecyltrichloro silane-coated glass in an aqueous medium was developed to construct a glucose biosensor by coating poly(acrylicacid-b-4-cynobiphenyl-4-oxyundecylacrylate) (PAA-b-LCP) at the aqueous/5CB interface and immobilizing glucose oxidase (GOx) covalently to the PAA chains. The glucose was detected from a homeotropic to planar orientational transition of 5CB by polarized optical microscopy under crossed polarizers. The maximum immobilization density of the GOx, 1.3 molecules/nm(2) obtained in this TEM grid cell enabled the detection of glucose at concentrations as low as 0.02 mM with a response time of 10 s. This liquid crystal-based glucose sensor provided a linear response of birefringence of the 5CB to glucose concentrations ranging from 0.05 to 2 mM with a Michaelis-Menten constant (Km) of 0.32 mM. This new and sensitive glucose biosensor has the merits of low production cost and easy detection through the naked eye and might be useful for prescreening the glucose level in the human body.

4-cyano-4'-pentylbiphenyl (5CB) microdroplets coated with PAA-b-LCP were successfully made via microfluidics. Their functionalized interfaces were examined for lysozyme and bovine serum albumin detection, which could be easily visualized with an optical microscope under crossed polarizers by the radial-to-bipolar configurational change of the 5CB. This transition was strongly dependent on the electrostatic states of the proteins and PAA chains, which were controlled by the pH of the water. This study demonstrated a simple approach for the development of a liquid crystal-based sensor for label-free detection of proteins, which may have diverse applications in various biomedical fields.

We are reporting for the first time the pH responsiveness of liquid crystal (LC) microdroplets decorated with an amphiphilic block copolymer of PAA-b-LCP. We successfully demonstrated the adsorption of block copolymer on LC droplets by fluorescence microscopy and pH response to the radial-to-bipolar orientational change of the LC droplets by changing pH from 12 to 2 through the polarized optical microscope (POM). We believe that our results may pave the way for the generation of monodisperse droplets decorated by various amphiphilic block copolymers which respond to several kinds of the external stimuli. These developments may be important for potential applications of the LC droplets in sensing and encapsulation fields.

A 4-cyano-4′-pentylbiphenyl (5CB)-filled transmission electron microscope (TEM) grid cell, which was functionalized by coating with a cationic surfactant dodecyltrimethylammonium bromide (DTAB) and the subsequent spontaneous adsorption of anionic deoxyribonucleic acid (DNA) at the liquid-crystal (LC)/aqueous interface was used for the detection of myricetin (MY) using a polarized optical microscope under crossed polarizers. The 5CB in contact with DTAB exhibited a homeotropic orientation, which subsequently changed to a planar one via electrostatic interactions between DNA and DTAB. When MY was injected into the TEM grid cell, the planar orientation changed to a homeotropic one due to the degradation of DNA by MY, which was confirmed by an electrophoresis method. The maximum adsorption of DNA (500 μg/mL) enabled the detection of 0.03 mM MY. The sensitivity of MY detection was enhanced in the presence of metallic salts of Fe and Cu. High stability, sensitivity, and ease of preparation of the TEM grid sensor make this new LC sensor suitable for the screening of trace amounts of MY. [ABSTRACT FROM AUTHOR]

• Reconfigurable light-responsive LCE actuators were fabricated with CNTs and allyl sulfide bonds. • CNTs dispersed in the LCE with amphiphilic dispersants induced high photothermal effects. • Allyl sulfide incorporated in the main chain showed excellent dynamic exchange reaction ability. • MLCE/CNT functionalized allyl disulfide widens the design ability with high performance. Monodomain liquid crystal elastomers (MLCEs), exhibiting a light-induced dynamic exchange reaction (DER) and light-triggered actuation abilities, were prepared using dispersed multiwalled carbon nanotubes (MWCNTs) and allyl sulfide linkages incorporated in the MLCE matrix. MWCNTs were dispersed in the MLCE matrix using a newly synthesized dispersant, poly(4-cyanobiphenyl-4′-oxyundecylacrylate-co-pyrene methyl acrylate); this dispersant exhibited amphiphilic properties of π–π interactions with the MWCNT fillers (attributed to the pyrene moieties) and miscibility with the MLCE matrix (attributed to the cyanobiphenyl mesogenic moieties). A low amount of well-dispersed MWCNTs (≤0.05 wt%) in the MLCE matrix induced excellent photothermal effects under near-infrared (NIR) light irradiation, leading to considerable reversible contraction/extension actuation (∼40 % change in length). The bilayer film comprising the MLCE and PLCE (PLCE: polydomain LCE) composite films bonded via DER without glue exhibited excellent bending actuation under NIR light irradiation and was configured into several actuators such as a flower-shaped actuator, a weightlifter, a circular rolling band, an oscillator mimicking a hummingbird, and a casting catapult. Therefore, this novel MLCE/CNT composite film enhances the design ability for the arbitrary shaping and functionalization of NIR light-triggerable LCE actuators, which can be applied to several interesting soft robots. [ABSTRACT FROM AUTHOR]

• Photoresponsive MLCE actuators with dynamic boron ester linakages were fabricated. • MLCE actuators exhibited low-temperature DBER with multi-source light responsiveness. • MLCE/PET bilayer actuators were fabricated via a glue-free welding method. • Bilayer actuators were applied to complex shapes with sophisticated motions. The liquid crystal elastomers (LCEs) possessing azobenzene moieties and boron ester bonds were prepared using Michael addition reaction and photopolymerisation. The azobenzene moieties imparted the LCEs with photoresponsiveness, whereas the boron ester bonds enabled the LCEs to undergo director alignment, reprogramming, and self-healing through a dynamic bond exchange reaction (DBER). This combined strategy overcame the competition between actuation and a DBER at high temperatures, which has been a drawback in the previously developed LCE vitrimers. Interestingly, the developed monodomain LCEs (MLCEs) showed the bending actuation in responsive to both UV and blue lights and unbending motion in responsive to green light, which paves the way for the design of new actuators for biomedical applications. Furthermore, taking advantage of the dynamic nature of boron ester chemistry, bilayer-structured actuators capable of thermo- or photo-controllable bending/unbending motions were fabricated by welding the MLCE film with a poly(ethylene terephthalate) substrate or itself below their nematic-to-isotropic transition temperatures via a 'glue-free' method. The MLCEs developed in this study can undergo multidirectional movements in response to different stimuli and can be used in applications such as microrobots, untethered biomimetic grippers, and surgical instruments. [ABSTRACT FROM AUTHOR]

A cholesterol biosensor was fabricated by coating 4-cyano-4′-pentylbiphenyl (5CB) in a transmission electron microscope (TEM) grid with poly(acrylicacid- b -4-cyno-4′-undecyl acrylate) (PAA- b -LCP), followed by co-immobilization of cholesterol oxidase and horseradish peroxidase on the PAA brushes. This TEM grid sensor was tested for stability and sensitivity of the immobilized enzymes to cholesterol. Cholesterol was detected by a planar-to-homeotropic orientational change of 5CB at a limit of 0.8 mM. The high stability, ease of preparation, and specific detection of cholesterol in a complex mixture, could provide a new and convenient method for screening cholesterol levels in a sample using a polarized optical microscope. [ABSTRACT FROM AUTHOR]

We report the sensing performances of liquid crystal-gated-organic field-effect transistors with a polymer dipole layer (DCL-LC-g-OFETs) upon physical touches. The DCL-LC-g-OFET devices, which were fabricated by employing 4-cyano-4’-pentylbiphenyl (5CB) as a sensing gate insulating layer, poly(methyl methacrylate) (PMMA) DCL, and 50 nm-thick poly(3-hexylthiophene) (P3HT) channel layer, which were optically semi-transparent and exhibited p-type transistor behavior. A pencil-like load (0.6 g–4.8 g) was introduced as a means for physical touch, while a human finger was used to examine the practical sensing capability of devices. Results showed that the drain current responded quickly upon physical touch and increased linearly with the strength of physical touch. The response time upon physical touch was slightly affected by the touch strength but was as fast as less than 1 s, while the drain current signals were quite reproducible and stable even after repeated physical touches. The present DCL-LC-g-OFET devices exhibited excellent sensing performances and reproducibility upon the human finger touch. [ABSTRACT FROM AUTHOR]

Abstract: This study aimed at elucidating the self-assembly structure of newly synthesized three-armed discotic liquid crystal molecules (DLCs) which give rise to small-angle X-ray scattering (SAXS) profiles that have difficulties in the direct determination of the symmetry of long-range intercolumnar lattice. The self-assembly structure of newly synthesized two analogues of DLCs, viz. 1,3,5-tris[2-(4-dodecyloxyphenyl)-oxadiazol-5-yl]benzene (TDOB) and 1,3,5-tris[2-(3,4,5-tris-dodecyloxyphenyl)-oxadiazol-5-yl]benzene (TTDOB), being discerned only in the number of dodecyloxyphenyl tails on each oxadiazol arm, were elucidated by comparative analyzes between experimentally observed SAXS profiles and those generated from a computational method. TTDOB molecules exhibited a typical SAXS profile of a hexagonal columnar mesophase, but TDOB molecules showed an ambiguous one hard to analyze. We found that, in TDOB molecules, the low degree of branching caused the localized conjugated electrons, which leads to weakening of interdisc interactions of core part and loosing the packing of disc molecules. And the free space between arms, afforded by a single branch on each arm, and electrostatic interactions between opposite charges on neighboring molecules which come from the localized electrons, allow TDOB columns to pack more closely than the disc diameter, then to form an interdigitated columnar structure. Such self-assembly structure is thought to be the result of the balance of various intermolecular interactions, so the self-assembly structures were tried to explain through a relative contribution of each intermolecular interaction component, that is, individual interaction energy values that we can calculate. With our proposed approaches, it is expected to widen our understanding of the self-assembly structures of various materials including DLCs. [ABSTRACT FROM AUTHOR]

Abstract: A series of discotic liquid crystals formed by simple hydrogen bonding between phloroglucinol core and alkoxystilbazole peripheral units was prepared. Nematic columnar and hexagonal columnar mesophases were observed depending on the length of alkyl chains around the aromatic core. [Copyright &y& Elsevier]