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ABSTRACT: New polyanionic and polyzwitterionic azobenzene ionic liquid-functionalized silica materials were designed based on the preparation of a new polymerizable azobenzene anionic monomer and either its cation-exchange with alkylimidazolium after grafting or the formation of an ionic liquid monomer pair before grafting onto silica.
Chemical Communications 02/2013; 49(24):2454-6. · 6.17 Impact Factor
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Emil Omurzak,
Tsutomu Mashimo,
Saadat Sulaimankulova,
Shintaro Takebe,
Liliang Chen,
Zhypargul Abdullaeva,
Chihiro Iwamoto,
Yudai Oishi, Hirotaka Ihara,
Hiroki Okudera,
Akira Yoshiasa
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ABSTRACT: In this study, a combination of magnetic nanoparticles (MNPs) together with cationic lipid N,N-di-n-hexadecyl-N,N-dihydroxyethylammonium chloride formulated with colipid cholesterol, upon magnetofection, enhanced DNA uptake into human glioblastoma-astrocytoma, epithelial-like cell line U-87 MG, hepatocellular carcinoma Hep G2, cervical cancer HeLa and breast cancer MDA-MB-231 cells. Having confirmed this, we monitored uptake of plasmid DNA mediated by ternary magnetoplexes by fluorescence microscopy, flow cytometry and reporter gene expression assays in the presence and absence of a magnetic field. Our observations clearly indicate enhanced transfection efficiency in vitro, upon magnetofection, in the presence of serum as seen from β-Gal reporter gene expression. The observed activity in serum suggests the suitability of MNPs for in vivo applications. Further, we measured the transverse relaxation time (T2) and obtained T2-weighted MRI images of treated U-87 MG cells. T2 determined for MNP-VP-Me22 and MNP-VP-Et22 corresponds to 22.6±0.8ms and 36.0±2.1ms, respectively, as compared to 47±1.7ms for control, suggesting their applicability in molecular imaging. Our results collectively highlight the potential of lipid-based approach to augment magnetic-field guided-gene delivery using MNPs and additionally towards developing intracellular molecular probes for magnetic resonance imaging.
International journal of pharmaceutics 02/2013; 446(1-2):87-99. · 2.96 Impact Factor
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ABSTRACT: Being different from common sensing molecules existing as monomer in solution, the gelators as sensing molecules self-assembled together in gels. Therefore, the interaction strength between gelators is believed as an important factor for gels to recognize selectively anions. In this paper, we choose two gelators, presenting similar binding sites for anions, but different strengths in intermolecular interaction. Moreover, their anion responsive behaviors in organogels were examined by observing phase state and measuring UV-vis and fluorescence spectra. We found that the organogel formed by with strong intermolecular interaction could selectively recognize fluoride anion. However, the gels of could be transformed into sol phases by addition of F(-), Cl(-), Br(-), AcO(-) and H(2)PO(4)(-) because of the small aggregate constant of in o-dichlorobenzene, presenting poor selectivity. Moreover, their UV-vis and emission spectra acting as testing methods also suggested the same conclusion.
Organic & Biomolecular Chemistry 02/2013; · 3.70 Impact Factor
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Liliang Chen,
Tsutomu Mashimo,
Chihiro Iwamoto,
Hiroki Okudera,
Emil Omurzak,
Hullathy Subban Ganapathy, Hirotaka Ihara,
Jidong Zhang,
Zhypargul Abdullaeva,
Shintaro Takebe,
Akira Yoshiasa
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ABSTRACT: CoC(x) nanoparticles encapsulated in carbon shells were synthesized using a pulsed plasma in liquid ethanol. This is the first time that monolithic cubic phase cobalt carbide nanoparticles have been obtained. X-ray diffraction refinement of the nanoparticles showed that the lattice parameter of prepared cubic phase cobalt carbide is larger than that of CoC(x) (44-0962) and cubic phase Co (15-0806 and 01-1259). The x-ray absorption fine structure spectra near the Co K-edge of the synthesized sample indicated differences from commercial metallic cobalt and cobalt oxide samples. High resolution transmission electron microscopy revealed that a thin carbon coating covered the surface of the nanoparticles. These carbon layers might isolate core CoC(x) material from the outside environment, and allow functionalization by carboxyl groups for the further purpose of targeted drug delivery. The obtained CoC(x)@C particles, with a crystallite size of about 10 nm confirmed by the electron microscope, aggregate into 20-40 nm secondary particles in distilled water as shown by dynamic light scattering, and possess high saturation magnetization of about 120 emu g(-1). The sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate assay and defragmentation of deoxyribonucleic acid on MCF-7 cells after incubation with particles indicate relatively low cytotoxicity of CoC(x)@C nanoparticles, compared with micro-sized and nano-sized metallic cobalt particles and commonly used iron oxides. For the small sized CoC(x)@C particles, the release of cobalt ions was checked by a chelation method with ethylenediaminetetraacetic acid solution to be at a very low level compared with other reference materials.
Nanotechnology 01/2013; 24(4):045602. · 3.98 Impact Factor
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ABSTRACT: A glutamide gelator, 1, was synthesized and a weak emission enhancement was observed during its gelation. In addition, 1 could be an excellent scaffold to embed successfully an energy acceptor, 2, into its aggregate to obtain a high efficient energy transfer. An amplification of the emission enhancement was observed in the two-component gels compared with the neat gel of 1 during gel formation. For example, 1 only induced a 2.5-fold increase in emission intensity, whereas a 23-fold enhanced emission could be observed in the two component gel with only 1.6 mol% of 2. Furthermore, two-component gels showed excited proton response. In systems with low acceptor concentrations, the hot solution redshifted the fluorescence from strong blue green to yellow upon the addition of a proton, which continuously blueshifted with decreasing temperature to form the gel given that the binding of the gelator to the proton is weakened during co-assembly. Moreover, the casting film formed by the two-component wet gel had excellent response to volatile acids such as hydrochloric acid, trifluoroacetic acid, and so on, and could be reversibly recovered by exposure to NH3.
Langmuir 12/2012; · 4.19 Impact Factor
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ABSTRACT: We introduce a new example of the in situ preparation and fabrication of stable gold nanoparticles on silica in an aqueous medium, by using only lipid-grafted silica particles in HAuCl(4) solution without addition of any external reducing agent. The lipid-grafted silica particles have been synthesized by graft-to methodology and characterized by elemental analysis, thermogravimetric analysis and Fourier-transform infrared spectroscopy. The metamaterial particles show high catalytic activity for the reduction of p-nitrophenol to p-aminophenol.
Nanotechnology 11/2012; 23(49):495301. · 3.98 Impact Factor
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ABSTRACT: The short peptide Boc-Phe-Aib-Phe-OH was synthesized and immobilized onto porous silica using grafting methodology. The resulting peptide-bonded silica was characterized using DRIFT-mode FT-IR, elemental analysis, thermogravimetric analysis, solid state C(13) NMR spectroscopy and the successful immobilization of the peptide on the silica support was confirmed. This grafted phase was packed into a stainless steel column and used for mixed-mode chromatography such as reversed-phase high-performance liquid chromatography and hydrophilic interaction liquid chromatography for the efficient separation of hydrophobic compounds, small polar molecules, and drug molecules. Compared with ODS and phenyl columns, this new stationary phase shows considerably higher molecular-planarity selectivity towards polyaromatic hydrocarbons and also available for separation of nucleo-analytes and sulfa-drug molecules in a hydrophilic interaction liquid chromatography mode. The multiple interactions induced by polar carbonyl group and hydrophobic phenyl group allow this peptide-modified silica to serve as a multi-mode stationary phase in high performance liquid chromatography.
Journal of chromatography. A 10/2012; · 4.19 Impact Factor
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ABSTRACT: A new hydrophilic tripeptide-based organosilica hybrid novel stationary phase has been developed for hydrophilic interaction chromatography (HILIC), enabling the efficient separation of bioactive polar molecules.
The Analyst 09/2012; 137(21):4907-9. · 4.23 Impact Factor
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ABSTRACT: In this paper, a new imidazolium-embedded C(18) stationary phase (SiImC(18)) for reversed-phase high-performance liquid chromatography is described. 1-Allyl-3-octadecylimidazolium bromide ionic liquid compound having a long alkyl chain and reactive groups was newly prepared and grafted onto 3-mercaptopropyltrimethoxysilane-modified silica via a surface-initiated radical-chain transfer addition reaction. The SiImC(18) obtained was characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, diffuse reflectance infrared Fourier transform, and solid-state (13)C and (29)Si cross-polarization/magic angle spinning nuclear magnetic resonance spectroscopy. The selectivity toward polycyclic aromatic hydrocarbons relative to that toward alkylbenzenes exhibited by SiImC(18) was higher than the corresponding selectivity exhibited by a conventional octadecyl silica (ODS) column, which could be explained by electrostatic π-π interaction cationic imidazolium and electron-rich aromatic rings. On the other hand, SiImC(18) also showed high selectivity for polar compounds, which was based on the multiple interaction and retention mechanisms of this phase with different analytes. 1,6-Dinitropyrene and 1,8-dinitropyrene, which form a positional isomer pair of dipolar compounds, were separated successfully with the SiImC(18) phase. Seven nucleosides and bases (i.e. cytidine, uracil, uridine, thymine, guanosine, xanthosine, and adenosine) were separated using only water as the mobile phase within 8min, which is difficult to achieve when using conventional hydrophobic columns such as ODS. The combination of electrostatic and hydrophobic interactions is important for the effective separation of such basic compounds without the use of any organic additive as the eluent in the octadecylimidazolium column.
Analytica chimica acta 08/2012; 738:95-101. · 4.31 Impact Factor
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ABSTRACT: The relationship between molecular gel-forming compound-based double-alkylated L-glutamide-derived functional group-integrated organic phase (Sil-FIP) structure and chromatographic performance is investigated and compared with widely used alkyl phases (C(30), polymeric and monomeric C(18)) as references. The functional group-integrated molecular gel on silica is chemically designed newly in a way that the weak interaction sites are integrated with high orientation and high selectivity can be realized by multiple interactions with the solutes. Its functions can be emphasized by being immobilizable with a terminal carboxyl group and the fact that five amide bonds including β-alanine subunit are integrated per molecule. Furthermore, its self-assembling function can be detected by monitoring of the chiroptical property. Temperature-dependent circular dichroism (CD) intensity was determined as an indicator of chirality for the gel forming compounds. (13)C cross-polarization magic angle spinning (CP/MAS) NMR spectra of the Sil-FIP phase indicate that predominance of gauche conformations exists at higher temperature (above 30 °C). (29)Si CP/MAS NMR were carried out to investigate the degree of cross-linking of the silane and silane functionality of the modified silica. Temperature-dependent (13)C CP/MAS NMR and suspended-state (1)H NMR measurements of the Sil-FIP phase exhibit the dynamic behavior of the alkyl chains. To correlate the NMR and CD results with temperature-dependent chromatographic studies, standard reference materials (SRM 869b and SRM 1647e), column selectivity test mixture for liquid chromatography was employed. Additional shape selectivity text mixtures were also used to clarify the mechanism of shape selectivity performance of Sil-FIP compared with commercially available columns. The evaluation with the spectroscopic and chromatographic analyses presents very important information on the surface morphology of the new organic phase and the molecular recognition process. Integrated and ordered functional groups were investigated to be the main driving force for very high molecular shape selectivity of the Sil-FIP phase.
Analytical Chemistry 07/2012; 84(15):6577-85. · 5.86 Impact Factor
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ABSTRACT: A novel alternating copolymer-based organic phase was synthesized using a new N-substituted maleimide monomer for the development of alternating copolymer-grafted silica for high-performance liquid chromatographic applications. This new monomer (DGMI) was copolymerized with octadecyl acrylate (ODA) from 3-mercaptopropyltrimethoxysilane-grafted silica to produce Sil-poly(ODA-alt-DGMI). The organic phase was characterized by the elemental analysis and the diffuse reflectance infrared Fourier transform spectroscopy. Tocopherol isomers and steroids were used as analytes for the evaluation of the chromatographic selectivity profiles of this novel stationary phase. The selectivity of this column was then compared with a polymeric ODS column and previously developed another alternating copolymer-grafted silica (without the glutamide-derived moiety) column, Sil-poly(ODA-alt-N-octadecylmaleimide). The complete baseline separation of tocopherol isomers in an isocratic mode has been achieved within 25 min with the Sil-poly(ODA-alt-DGMI). The separation of eight kinds of estrogenic steroids and corticoids has also been achieved in an isocratic mode with this column. Significant differences in separation selectivity between Sil-poly(ODA-alt-DGMI) and polymeric ODS columns were observed towards the steroids, and compared with the reference columns, a better separation profile for these analytes was obtained with the Sil-poly(ODA-alt-DGMI). The results of this investigation indicated that the enhancement of selectivity of Sil-poly(ODA-alt-DGMI) towards the test analytes arose from the multiple interaction mechanism such as hydrophobic effect, carbonyl-π and hydrogen-bonding interactions, and such integrated interactions originated from the addition of two amide groups in the N-substituted maleimide monomer.
Analytical and Bioanalytical Chemistry 06/2012; 404(1):229-38. · 3.78 Impact Factor
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ABSTRACT: Herein, some magnetic nanoparticles (MNP)/clay/polymer nanocomposites have
been prepared, whose saturation magnetization is higher than that of pure oleic
acid coated MNP component. The existence of unique 'nano-network' structure and
tight three-phase nano-interface in the nanocomposites contribute to the
surprising saturation magnetization.
06/2012;
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ABSTRACT: Poly(2-N-carbazolylethyl acrylate) with terminal trimethoxysilyl groups was prepared as an organic phase and immobilized onto silica.
The retention behavior of the column packed with this carbazole-based polymer-immobilized silica (Sil-CEA) was investigated
by using various estrogenic steroids and corticoids in both reversed-phase and normal-phase liquid chromatography. As a result,
complete separation was confirmed for eight kinds of steroids with Sil-CEA. The most specific separation with Sil-CEA can
be emphasized by the high separation factor (e.g., α = 1.39 in methanol–water (7:3, v/v) at 35°C) for 17α and 17β-estradiols, one of the most difficult pairs of isomers in chromatographic separation, whereas
for two kinds of commercially available polymeric ODS columns as references α = 1.01, only, under the same conditions. Because the excellent separation and retention order with Sil-CEA was maintained
even in a normal-phase mobile phase such as a hexane–2-propanol, it is estimated that the CEA phase has multiple interaction
mechanisms through stronger interactions such as dipole–dipole, carbonyl–π, and hydrogen bonding interactions than the hydrophobic
effect expected with ODS.
KeywordsCarbazole-based polymer-Separation-Steroids-Solvent effect
Analytical and Bioanalytical Chemistry 04/2012; 397(2):623-629. · 3.78 Impact Factor
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ABSTRACT: A new helical aromatic oligoamide foldamer, bearing triethyleneglycol side chains for solubility in a broad range of media, was prepared. The stability of the helical conformation was assessed in various solvents and shown to vary greatly and unexpectedly. Stability was remarkably enhanced in methanol-water mixtures.
Chemical Communications 04/2012; · 6.17 Impact Factor
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ABSTRACT: A new poly(ionic liquid)-grafted silica stationary phase was prepared and characterized. It was then applied for multi-mode chromatographies, including ion-exchange, reversed-phase, and hydrophilic interaction liquid chromatographies for the effective separation of anions, hydrophobic compounds, and small polar molecules, respectively.
The Analyst 04/2012; 137(11):2553-5. · 4.23 Impact Factor
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ABSTRACT: Enantioselective recognition of amino acids was achieved by using a highly ordered chiral assembly of achiral porphyrin on a chiral molecular gel. Exceptionally high enantioselectivity was observed for histidine derivatives by monitoring the CD patterns and fluorescence quenching, K(SV) (l): 26.3 × 10(3) M(-1); K(SV)(D)-enantiomer: 7.03 × 10(3) M(-1).
Chemical Communications 04/2012; 48(40):4881-3. · 6.17 Impact Factor
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ABSTRACT: A gelator that consisted of one benzimidazole moiety and four amide units was used as a chemosensor. We found that its absorption and emission spectra in solution were sensitive to two complementary chemical stimuli: protons and anions. Thus, YES and INH logic gates were obtained when absorbance was defined as an output. A combination gate of XNOR and AND with an emission output was also obtained. Moreover, wet gels in two solvents were used to construct two more-complicated three-input-three-output gates, owing to the existence of the gel phase as an additional output. Finally, in xerogel films that were formed from two kinds of wet gels, reversible changes in their emission spectra were observed when they were sequentially exposed to volatile acid and NH(3). Another combination two-output logic gate was obtained for xerogel films. Finally, three states of the gelator were used to construct not only basic logic gate, but also some combination gates because of their response to multiple chemical stimuli and their multiple output signals, in which one chemical input could erase the effect of another chemical input.
Chemistry 02/2012; 18(12):3549-58. · 5.93 Impact Factor
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ABSTRACT: We synthesized new dispersive chitosan particles at circumneutral pH. Particles composed of a chitosan-borate complex were synthesized by a method consisting of two simple steps: mixture and dialysis. As this method does not employ reagents such as organic solvents or surface-active agents and does not require heat treatment, it has a minimal negative impact on the environment. Crosslinking of the reaction of glucose and boric acid at ordinary temperature and pressure led to the formation of composite particles. Stereoscopic microscopy and investigation of the particle size distribution by dynamic light scattering (DLS) revealed that particles ranging in size from submicrons to several microns with high dispersibility in water were obtained. Even after heat treatment at 80°C for 12h, the particles maintained their composite formation, indicating that they have high thermal stability. Chitosan powders demonstrated inadequate antimicrobial properties at circumneutral pH, but the particles of the chitosan-borate complex had antimicrobial properties against the gram-negative bacterium, Escherichia coli, and the gram-positive bacterium, Staphylococcus aureus, as well as the fungi Aspergillus niger and Fusarium solani. These results indicated that the particles of the chitosan-borate complex had a broad antimicrobial spectrum at circumneutral pH.
Carbohydrate research 02/2012; 349:52-8. · 2.03 Impact Factor
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ABSTRACT: Polymerizable ionic liquid monomer pairs were designed and copolymerized on silica as a new strategy to prepare multifunctional hybrid materials in hydrophobic and hydrophilic interaction chromatographies with enhancements of selectivity and stability.
Chemical Communications 12/2011; 48(9):1299-301. · 6.17 Impact Factor
