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Sang Yup Lee - One of the best experts on this subject based on the ideXlab platform.
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block copolymer membranes with catecholic Bolaamphiphile assemblies
Journal of Membrane Science, 2018Co-Authors: Jung Pyo Jung, Chaemyeong Lee, Sang Yup Lee, Jae Hun Lee, Jong Hak KimAbstract:Abstract We report the first use of the assemblies of catecholic bolaamphiphilic compound, i.e., bis-(N-α-amido-3,4-dihydroxyphenylalanine)−1,7-heptane dicarboxylate (DOPA-C7), as an organic filler for gas separation membranes. Specifically, the membranes were prepared by adding the assembly fillers to a block copolymer matrix, i.e., nonpolar polystyrene-b-polybutadiene-b-polystyrene (SBS) or polar poly (ether-b-amide) (PEBAX). The interaction between the filler and matrix was investigated regarding the structure, morphology, and CO2/N2 separation performance. The strongly interacting PEBAX/DOPA-C7 membranes showed a typical trade-off behavior, i.e., a decrease in CO2 permeability and increase in CO2/N2 selectivity with the filler contents. In contrast, the weakly interacting SBS/DOPA-C7 interestingly showed an improved CO2/N2 selectivity, from 14.1 to 21.1, with a slight increase in CO2 permeability (from 347.5 to 349.7 Barrer) owing to the catechol group of DOPA-C7 that can function as a Lewis base. This indicates that very strong interactions between the polymeric matrix and filler could have a negative impact on the gas separation performance. This work not only explores the importance of a polymer matrix, but also opens up the feasibility of using a catecholic compound in gas separation membranes.
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iridium coordinated histidyl Bolaamphiphile self assemblies as heterogeneous catalysts for water oxidation
Chemsuschem, 2018Co-Authors: Changjoon Keum, Sang Yup LeeAbstract:Catalysts that can promote oxygen evolution from water are necessary for green energy production. In this study, colloidal heterogeneous catalysts for oxygen evolution were prepared by coordination of Ir species to self-assemblies of histidyl Bolaamphiphiles. When dissolved in water, the histidyl Bolaamphiphiles self-assembled to form particulate structures with the exposure of densely packed histidine imidazoles on their surface. Subsequent coordination of the Ir species to the Bolaamphiphile assembly gave rise to catalytic activity toward the oxygen evolution reaction. The oxygen evolution was examined by using the catalytic assemblies in the presence of a sacrificial oxidant, cerium ammonium nitrate. The Ir-coordinated assemblies showed a turnover frequency of 13 min-1 , which was comparable to those previously reported for molecular water oxidation catalysts. The catalytic activity increased with increasing histidine imidazole/Ir molar ratio, which suggested that multiple coordination of Ir to imidazoles facilitated the formation of active Ir intermediates. This study demonstrates the feasibility of constructing catalytically active interfaces from colloidal Bolaamphiphile assemblies with biochemical ligands.
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photoinduced intermolecular electron transfer mediated by the colloidal tyrosyl Bolaamphiphile assembly
ChemPhysChem, 2018Co-Authors: Junghyun Cho, Jin Young Kwak, Dongho Kim, Sang Yup LeeAbstract:The self-assembly of tyrosyl Bolaamphiphiles is exploited to create a colloidal protein-like host matrix, upon which sacrificial electron-donor molecules associate to create a photosystem II (PSII) mimetic electron-relay system. This system harnesses the tyrosine phenol groups abundant on the surface of the assemblies to mediate photoinduced intermolecular electron transfer. Compared with the l-tyrosine molecules, the tyrosyl Bolaamphiphile assembly facilitates electron transfer from the sacrificial electron donor to the oxidized photosensitizer. The enhanced electron relay is likely to be driven by the host function of the assembly associated with the sacrificial electron donor and by the suppression of the oxidative cross-linking of phenoxyl radicals. The tyrosyl Bolaamphiphile assembly is advantageous in the construction of a PSII mimetic system with a protein-like nature and displaying biochemical functions.
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enhanced cell adhesion on a nano embossed sticky surface prepared by the printing of a dopa Bolaamphiphile assembly ink
Scientific Reports, 2017Co-Authors: Chaemyeong Lee, Seunghyun Kim, Jae Hyung Jang, Sang Yup LeeAbstract:Inspired by adhesive mussel proteins, nanospherical self-assemblies were prepared from Bolaamphiphiles containing 3,4-dihydroxyphenylalanine (DOPA) moieties, and a suspension of the Bolaamphiphile assemblies was used for the preparation of a patterned surface that enhanced cell adhesion and viability. The abundant surface-exposed catechol groups on the robust Bolaamphiphile self-assemblies were responsible for their outstanding adhesivity to various surfaces and showed purely elastic mechanical behaviour in response to tensile stress. Compared to other polydopamine coatings, the spherical DOPA-Bolaamphiphile assemblies were coated uniformly and densely on the surface, yielding a nano-embossed surface. Cell culture tests on the surface modified by DOPA-Bolaamphiphiles also showed enhanced cellular adhesivity and increased viability compared to surfaces decorated with other catecholic compounds. Furthermore, the guided growth of a cell line was demonstrated on the patterned surface, which was prepared by inkjet printing using a suspension of the self-assembled particles as an ink. The self-assembly of DOPA-Bolaamphiphiles shows that they are a promising adhesive, biocompatible material with the potential to modify various substances.
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hemin bound cysteinyl Bolaamphiphile self assembly as a horseradish peroxidase mimetic catalyst
RSC Advances, 2017Co-Authors: Chaemyeong Lee, Sang Yup LeeAbstract:Horseradish peroxidase (HRP) is an important oxidative enzyme with a heme cofactor whose Fe centre acts as the active site. Its catalytic activity is expressed upon association with the heme cofactor through coordination between Fe and histidine imidazole. In this study, a HRP-mimetic catalyst was prepared by binding hemin to the self-assembled suprastructure of cysteinyl Bolaamphiphiles through an Fe–thiol bond, and its oxidative catalytic activity was investigated. The cysteinyl Bolaamphiphile self-assembly is rich with surface-exposed cysteine thiols, which served as binding sites. The activity of the prepared HRP-mimetic catalyst was pH-dependent and increased with increasing temperature, with an activation energy of 31.7 kJ mol−1. The kinetic parameters obtained by varying the substrate concentrations suggested a ping-pong mechanism where H2O2 and substrate bind sequentially to the active centre. The cysteinyl Bolaamphiphile self-assembly provides a biomimetic support on which various metallic cofactors can bind to induce biochemical activity.
Minghua Liu - One of the best experts on this subject based on the ideXlab platform.
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copper ii ion selective and strong acid tolerable hydrogels formed by an l histidine ester terminated Bolaamphiphile from single molecular thick nanofibers to single wall nanotubes
Chemical Communications, 2013Co-Authors: Yaqing Liu, Tianyu Wang, Minghua LiuAbstract:An L-histidine ester terminated Bolaamphiphile (BolaHis) was found to form hydrogels and self-assemble into single-wall nanotubes and single molecular thick fibers triggered by proton and copper ions, respectively. The hydrogels showed good tolerance to a concentrated acid environment and excellent selectivity towards Cu2+ over other metal ions.
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interfacial assembly of cinnamoyl terminated Bolaamphiphiles through the air water interface headgroup dependent assembly supramolecular nanotube and photochemical sewing
Physical Chemistry Chemical Physics, 2011Co-Authors: Xufei Liu, Tianyu Wang, Minghua LiuAbstract:A series of cinnamoyl-terminated Bolaamphiphiles were synthesized and their assemblies at the air/water interface were investigated. It was found that the assembly behaviour depended on the substituted groups on the cinnamoyl unit. The Bolaamphiphile with 4-hydroxycinnamoyl head groups (HCDA) was found to assemble into a supramolecular nanotube, while the others formed only layer-structured films. Moreover, the nanotube formed from HCDA showed supramolecular chirality due to the symmetry breaking. Both the layered films and the nanotubes showed photochemical dimerization upon UV irradiation, which were studied from the UV-Vis, FT-IR spectral and MALDI-TOF MS analysis. Interestingly, such dimerization behavior of the cinnamoyl group could be used to stabilize the nanotube of HCDAvia photochemical sewing. During such a process both the supramolecular chirality and the tubular shapes were kept. Remarkably, such a photochemical sewed chiral nanotube could further induce the chirality of an achiral porphyrin derivative assembled on it, and produced the induced chirality without using any chiral molecules.
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hierarchical self assembly of Bolaamphiphiles with a hybrid spacer and l glutamic acid headgroup ph and surface triggered hydrogels vesicles nanofibers and nanotubes
Langmuir, 2010Co-Authors: Tianyu Wang, Jian Jiang, Yu Liu, Minghua LiuAbstract:Bolaamphiphiles with l-glutamic acid headgroups and hybrid linkers, each composed of two rigid benzene rings and different polymethylene units, were designed, and morphological controls of the hierarchical self-assemblies were realized via changing solution pH and application to solid surfaces. At a low pH of 3, Bolaamphiphiles formed hydrogels with water and molecules with short and long spacers formed nanofibers and helical nanoribbon−nanotubes, respectively. In a pH 12 aqueous solution, vesicles were observed from cryo-TEM measurements for amphiphiles with short spacers that could transfer to huge vesicles when cast onto a mica surface. Amphiphiles with longer spacers self-assembled into nanoparticles in a pH 12 aqueous solution while micellar fibers were formed on a mica surface. Those assemblies were characterized with UV−vis, CD, and FT-IR spectroscopy and AFM and TEM observations. With molecular structure modification and the fine tuning of conditions, morphology transitions between various nanostr...
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compression induced helical nanotubes in a spreading film of a Bolaamphiphile at the air water interface
Langmuir, 2006Co-Authors: Peng Gao, Minghua LiuAbstract:Inspired by the elegant helical structures endowed by mother nature, we designed an l-glutamic acid terminated Bolaamphiphile and obtained helical nanotubes through the manipulation on the two-dimensional Langmuir films at the air/water interface. It has been found that on the subphase with a pH value lower than 3, stable monolayers with plateau regions were obtained for the Bolaamphiphile. Although a flat and uniform morphology was observed for the film deposited at a surface pressure below the plateau region, helical nanotube structures were obtained when the film was compressed over the plateau region. It was suggested that the compression of the monolayer at the air/water interface caused the one end of the Bolaamphiphile to leave from the water surface and form an intermediate monolayer in which one end group attached on the water surface and the other extruded in the air. Such an intermediate monolayer subsequently rolled into a helical structure due to the chiral nature of the l-glutamic acid headg...
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controlled synthesis of double and multiwall silver nanotubes with template organogel from a Bolaamphiphile
Langmuir, 2006Co-Authors: Peng Gao, Chuanlang Zhan, Minghua LiuAbstract:Double- and multiwall silver nanotubes were synthesized by using the uniform low-molecular-mass organogel nanotubes self-assembled from an l-glutamic-acid-based Bolaamphiphile, N,N-eicosanedioyl-di-l-glutamic acid (EDGA). The EDGA could gel a mixed water/ethanol solvent and form helical nanotubes. When the gel thus formed was mixed with AgNO3 in water/ethanol, the silver(I) cations could be coordinated with both the inner and outer surfaces of the EDGA nanotubes. The reduction of the silver cation under the photoirradiation yielded double-wall silver nanotubes, where two silver layers were separated by one EDGA layer. Elongations of the reduction time of the mixed gels and AgNO3 in the solution lead to the formation of three-, four-, and five-wall silver nanotubes. In these multiwall silver nanotubes, each wall was separated at a distance of about 2.7 nm, which was just the molecular length of the Bolaamphiphile. It was suggested that the dissolved EDGA molecules and excess AgI cations were further assemb...
Bruce A Shapiro - One of the best experts on this subject based on the ideXlab platform.
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in silico and in ex vivo experiments indicate the potential of nanoparticles composed of rna Bolaamphiphile complexes as a therapeutic sirna delivery vehicle
Biophysical Journal, 2012Co-Authors: Taejin Kim, Eliahu Heldman, Robert Blumenthal, Kirill A Afonin, Bruce A ShapiroAbstract:Speciific siRNA that are designed to silence oncogenic pathways can be used for cancer therapy.However, naked siRNAs have short half-lives in the blood stream and have difficulties in crossing biological membranes due to their negative charges. These biological barriers can be overcome by using siRNA-Bolaamphiphile complexes. Bolaamphiphiles have two positively charged hydrophilic head groups connected by a hydrophobic chain and they have a relatively low toxicity and long persistence in the blood stream. In this study, we investigated the interactions between Bolaamphiphiles and siRNA and correlated these interactions with gene silencing efficacy. Two different types of Bolaamphiphiles have been studied, GLH19 and GLH20, each having different head group structures. Our explicit solvent molecular dynamics (MD) simulations showed that these Bolaamphiphiles associate with RNA due to (1) electrostatic interactions, (2) hydrogen bond interactions and (3) hydrophobic interactions. We found that GLH20 head groups interacted with the RNA by electrostatic and strong hydrogen bond interactions, while GLH19 head groups associated with the RNA mainly by electrostatic interactions. Studies of agarose gel electrophoresis indicated weaker interaction of GLH19 with siRNA as compared to the interaction between siRNA and GLH20. In high salt concentration and in the presence of Triton X100, siRNA was released from GLH19 complexes, while the siRNA-GLH20 complex remained intact. In transfection experiments, the siRNA-GLH19 complex was more effective than siRNA-GLH20 complex. These MD simulations and experimental results suggest that siRNA is released from the siRNA-GLH19 complex within the cells faster than from the siRNA-GLH20 complex, enabling more effective gene silencing when the siRNA-GLH19 complex is used for the transfection. Therefore,we propose that siRNA-GLH19 complexes are strong candidates as vehicles for therapeutic purposes.
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molecular dynamics simulations of sirna Bolaamphiphile nanoparticle complexes suggest their potential as a therapeutic sirna delivery vehicle
Biophysical Journal, 2011Co-Authors: Taejin Kim, Eliahu Heldman, Robert Blumenthal, Bruce A ShapiroAbstract:In spite of the strong potential as a therapeutic, naked siRNA delivery in vivo has some problems that need to be overcome. siRNAs need to remain intact in the blood stream and they have to overcome the strong negative charges that are present on the phosphate groups of the RNA backbone when crossing biological membranes. These biological barriers can be surmounted by covering or encapsulating the siRNA with Bolaamphiphiles. Bolaamphiphiles have two positively charged hydrophilic head groups connected by a hydrophobic chain and they can form stable monolayer membrane vesicles which can encapsulate water soluble anionic molecules. In addition, Bolaamphiphiles have a relatively low toxicity level when compared to lipids and can persist in the blood for long time periods. This research involves the study of RNA shape-based and vesicle-based approaches for RNA-nanoparticle formation, with the ultimate goal of developing an siRNA delivery vehicle. In the shape-based approach, we utilize differently shaped siRNA scaffolds for RNA nanoparticle-Bolaamphiphile complex formation. In the vesicle-based approach, siRNAs are encapsulated inside Bolaamphiphile vesicles or bound to the vesicle surface. Our explicit solvent molecular dynamics (MD) simulation results show that Bolaamphiphiles rapidly cover RNA duplexes due to the strong interaction between the cationic head groups in Bolaamphiphiles and the negative charges on the phosphate groups of the RNA backbone. It is also observed that the Bolaamphiphile head groups populate both the minor and major grooves and that once Bolaamphiphiles associate with the RNA, the base G forms stable hydrogen bonds with the head groups of the Bolaamphiphiles. Therefore, our research suggests that siRNA nanoparticle-Bolaamphiphile complexes behave in such a way to be a strong candidate for the development of therapeutic siRNA nanoparticle delivery vehicles.
Eliahu Heldman - One of the best experts on this subject based on the ideXlab platform.
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fusion of Bolaamphiphile micelles a method to prepare stable supported biomimetic membranes
Langmuir, 2013Co-Authors: Yair Kaufman, Eliahu Heldman, Sarina Grinberg, Charles Linder, Jack Gilron, Viatcheslav FregerAbstract:Supported biomimetic membranes (SBMs) on solid substrates have been commonly prepared from vesicle-forming double-tail lipids, such as zwitterionic phospholipids, using the method of vesicle fusion. Here we report on the preparation of SBMs on silica surfaces via a similar process of "micelle fusion" from a cationic single-tail Bolaamphiphile GLH-20 that forms spherical and elongated thread-like micelles in solution. We demonstrate that, in contrast to zwitterionic phospholipids, GLH-20 self-assembles into a stable contiguous SBM at both low and high ionic strengths. The cationic charge of GLH-20 promotes the formation of a stable SBM through enhanced double-layer interactions with the negatively charged silica surface. It is also shown that spinach aquaporin PM-28 was successfully incorporated within Bolaamphiphile SBM in a manner similar to SBMs prepared by vesicle/proteoliposome fusion; thereby the inherent curvature of the micelle surface does not inhibit protein reconstitution. The results suggest that SBMs based on charged Bolaamphiphiles might be an attractive platform for applications such as water purification and biosensors, where the stability and low defect rate of SBMs in diverse conditions are crucial for achieving desired performance.
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site directed decapsulation of bolaamphiphilic vesicles with enzymatic cleavable surface groups
Journal of Controlled Release, 2012Co-Authors: Mary Popov, Sarina Grinberg, Charles Linder, Tal Waner, Bosmat Levihevroni, Richard J Deckelbaum, Eliahu HeldmanAbstract:Stable nano-sized vesicles with a monolayer encapsulating membrane were prepared from novel Bolaamphiphiles with choline ester head groups. The head groups were covalently bound to the alkyl chain of the Bolaamphiphiles either via the nitrogen atom of the choline moiety, or via the choline ester's methyl group. Both types of Bolaamphiphiles competed with acetylthiocholine for binding to acetylcholine esterase (AChE), yet, only the choline ester head groups bound to the alkyl chain via the nitrogen atom of the choline moiety were hydrolyzed by the enzyme. Likewise, only vesicles composed of Bolaamphiphiles with head groups that were hydrolyzed by AChE released their encapsulated material upon exposure to the enzyme. Injection of carboxyfluorescein (CF)-loaded vesicles with cleavable choline ester head groups into mice resulted in the accumulation of CF in tissues that express high AChE activity, including the brain. By comparison, when vesicles with choline ester head groups that are not hydrolyzed by AChE were injected into mice, there was no accumulation of CF in tissues that highly express the enzyme. These results imply that bolaamphiphilic vesicles with surface groups that are substrates to enzymes which are highly expressed in target organs may potentially be used as a drug delivery system with controlled site-directed drug release.
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in silico and in ex vivo experiments indicate the potential of nanoparticles composed of rna Bolaamphiphile complexes as a therapeutic sirna delivery vehicle
Biophysical Journal, 2012Co-Authors: Taejin Kim, Eliahu Heldman, Robert Blumenthal, Kirill A Afonin, Bruce A ShapiroAbstract:Speciific siRNA that are designed to silence oncogenic pathways can be used for cancer therapy.However, naked siRNAs have short half-lives in the blood stream and have difficulties in crossing biological membranes due to their negative charges. These biological barriers can be overcome by using siRNA-Bolaamphiphile complexes. Bolaamphiphiles have two positively charged hydrophilic head groups connected by a hydrophobic chain and they have a relatively low toxicity and long persistence in the blood stream. In this study, we investigated the interactions between Bolaamphiphiles and siRNA and correlated these interactions with gene silencing efficacy. Two different types of Bolaamphiphiles have been studied, GLH19 and GLH20, each having different head group structures. Our explicit solvent molecular dynamics (MD) simulations showed that these Bolaamphiphiles associate with RNA due to (1) electrostatic interactions, (2) hydrogen bond interactions and (3) hydrophobic interactions. We found that GLH20 head groups interacted with the RNA by electrostatic and strong hydrogen bond interactions, while GLH19 head groups associated with the RNA mainly by electrostatic interactions. Studies of agarose gel electrophoresis indicated weaker interaction of GLH19 with siRNA as compared to the interaction between siRNA and GLH20. In high salt concentration and in the presence of Triton X100, siRNA was released from GLH19 complexes, while the siRNA-GLH20 complex remained intact. In transfection experiments, the siRNA-GLH19 complex was more effective than siRNA-GLH20 complex. These MD simulations and experimental results suggest that siRNA is released from the siRNA-GLH19 complex within the cells faster than from the siRNA-GLH20 complex, enabling more effective gene silencing when the siRNA-GLH19 complex is used for the transfection. Therefore,we propose that siRNA-GLH19 complexes are strong candidates as vehicles for therapeutic purposes.
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molecular dynamics simulations of sirna Bolaamphiphile nanoparticle complexes suggest their potential as a therapeutic sirna delivery vehicle
Biophysical Journal, 2011Co-Authors: Taejin Kim, Eliahu Heldman, Robert Blumenthal, Bruce A ShapiroAbstract:In spite of the strong potential as a therapeutic, naked siRNA delivery in vivo has some problems that need to be overcome. siRNAs need to remain intact in the blood stream and they have to overcome the strong negative charges that are present on the phosphate groups of the RNA backbone when crossing biological membranes. These biological barriers can be surmounted by covering or encapsulating the siRNA with Bolaamphiphiles. Bolaamphiphiles have two positively charged hydrophilic head groups connected by a hydrophobic chain and they can form stable monolayer membrane vesicles which can encapsulate water soluble anionic molecules. In addition, Bolaamphiphiles have a relatively low toxicity level when compared to lipids and can persist in the blood for long time periods. This research involves the study of RNA shape-based and vesicle-based approaches for RNA-nanoparticle formation, with the ultimate goal of developing an siRNA delivery vehicle. In the shape-based approach, we utilize differently shaped siRNA scaffolds for RNA nanoparticle-Bolaamphiphile complex formation. In the vesicle-based approach, siRNAs are encapsulated inside Bolaamphiphile vesicles or bound to the vesicle surface. Our explicit solvent molecular dynamics (MD) simulation results show that Bolaamphiphiles rapidly cover RNA duplexes due to the strong interaction between the cationic head groups in Bolaamphiphiles and the negative charges on the phosphate groups of the RNA backbone. It is also observed that the Bolaamphiphile head groups populate both the minor and major grooves and that once Bolaamphiphiles associate with the RNA, the base G forms stable hydrogen bonds with the head groups of the Bolaamphiphiles. Therefore, our research suggests that siRNA nanoparticle-Bolaamphiphile complexes behave in such a way to be a strong candidate for the development of therapeutic siRNA nanoparticle delivery vehicles.
Toshimi Shimizu - One of the best experts on this subject based on the ideXlab platform.
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Bolaamphiphile based nanotubes
2021Co-Authors: Toshimi ShimizuAbstract:In nature, cell membranes of eubacteria and archaea are composed of totally different bilayer- and monolayer-based phospholipid membranes, respectively. Meanwhile, in a synthetic system, the functionality of the nanotube interior and exterior surfaces differs between the bilayer- and monolayer-based nanotubes. The self-assembled monolayer-based nanotubes from Bolaamphiphiles can be utilized for the selective modification of their interior or exterior surfaces. This chapter discusses the preparation, functions, and applications of Bolaamphiphile-based nanotubes. First, the self-assembly of simple 1-glucosamide-based Bolaamphiphiles having hydrophobic long alkyl chains and a hydrophilic carboxylic acid headgroup at one end. By employing this unsymmetrical Bolaamphiphiles, the author’s group demonstrated a practical control over the inner diameters of the self-assembled nanotubes. Endo-complexation of the terminal carboxylate headgroup of a Bolaamphiphile with cisplatin result in the formation of a cisplatin-encapsulated SMNTs. The author next addresses the transportation behavior of proteins in a confined nanochannel prepared from functional Bolaamphiphiles. Moreover, binary co-assembly and multistep self-assembly techniques are discussed in terms of interior and/or exterior surface modification. This chapter also describes the characteristic properties of Bolaamphiphile-based nanotubes, which include chirality induction for entrapped achiral polythiophenes, thermally controllable extraction and separation of peptides, protein stabilization and folding, enzymatic channel reactor, and interlink of a heterogeneous pair of nanochannels.
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nanofiber formation from sequence selective dna templated self assembly of a thymidylic acid appended Bolaamphiphile
Chemical Communications, 2008Co-Authors: Mayumi Ohnishikameyama, Rika Iwaura, Toshimi ShimizuAbstract:Quaternary self-assembly of a thymidylic acid-appended Bolaamphiphile, with heteropolymeric DNA as a template, produced supramolecular helical nanofibers in the presence of specific target DNA.
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supramolecular polyglycine ii type structure of glycylglycine Bolaamphiphile
Supramolecular Chemistry, 1998Co-Authors: Masaki Kogiso, Mitsutoshi Masuda, Toshimi ShimizuAbstract:Abstract Bolaamphiphile with a glycylglycine unit at each end, N,N′-bis(carboxymethylcarbamoylmethyl)decane-1, 10-dicarboxamide, has been synthesized. The crystal structure was determined by single-crystal X-ray analysis. The space group is P21/a with unit cell parameters: a = 8.678(3), b = 4.873(4), c = 27.161(3) A, β = 92.68(2)°, Z = 2, Dc = 1.33g/cm3, and R = 0.051 for 2095 data. The two halves of the molecule are related by a center of symmetry and have a folded [sbnd] CH2 [sbnd] CH2 [sbnd] CO [sbnd] conformation (TGS or TGS). The molecules are arranged in a layered structure along the c-axis, forming a linear polymolecular chain stabilized by acid-acid dimerization at each end. Each chain is arranged in a pseudo-hexagonal lattice stabilized by three-dimensional hydrogen-bond networks between amide groups. This supramolecular crystal structure provides the first example of polyglycine II-type structure made of noncovalent polymolecular chains.
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non mesogenic crystal structure of a synthetic 1 d glucosamide Bolaamphiphile
Carbohydrate Research, 1997Co-Authors: Mitsutoshi Masuda, Toshimi ShimizuAbstract:Abstract The crystal structure of the synthetic 1-glucosamide Bolaamphiphile, N,N′- bis (β- d - glucopyranosyl)undecane-1,11-dicarboxamide (1) was determined by single-crystal X-ray analysis. The space group is P 2 1 , with cell dimensions: a = 6.220(1), b = 48.25(1), c = 4.922(2) A , β = 105.67(2)°, and Z = 2 . The glucopyranosyl ring is in a 4 C 1 , chair conformation. The Bolaamphiphile molecules are arranged in a layered structure with the alkylene chains packed antiparallel in a pleated sheet. The glucosamine moieties are linked by a three-dimensional intermolecular hydrogen-bonding network. The n -alkylene chain has an all- trans zigzag conformation with a small left-handed twist. Synthetic 1-glucosamide Bolaamphiphile self-assembled to form a head-to-head layered structure with an all- trans , n -alkylene link, which was stabilize by three dimensional hydrogen-bonding network.
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hydrogen bond assisted layered assembly and hydrocarbon chain kink defect of a synthetic 1 galactosamide Bolaamphiphile
Chemistry Letters, 1997Co-Authors: Toshimi Shimizu, Mitsutoshi Masuda, Motonari ShibakamiAbstract:A hydrogen-bond-assisted layered assembly of the synthetic 1-galactosamide Bolaamphiphile, N,N′-bis(β-D-galactopyranosyl)decane-1,10-dicarboxamide has been characterized by single crystal analysis. The molecular structure includes a “kink” conformation of the connecting decamethylene chain based on a gauche-trans-gauche′ sequence.