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Search for "gels" in Full Text gives 90 result(s) in Beilstein Journal of Organic Chemistry.
One-pot synthesis of block-copolyrotaxanes through controlled rotaxa-polymerization
Beilstein J. Org. Chem. 2017, 13, 1310–1315, doi:10.3762/bjoc.13.127
- polymers without chemical modification of the backbone. Through polyrotaxane formation solubility [2][3][4][5], as well as mechanical [1][2][3][6][7][8][9] and electrical properties [10], can be improved. Cross-linking of threaded macrocycles gives rise to so-called slide-ring gels with unique mechanical
- polyrotaxanes was already investigated in the fields of biomedicine, as drug [22] or gene [23] delivery vehicles, or in materials sciences, as slide ring gels [6]. Polyrotaxanes are mostly synthesized by a threading approach [2], a multistep method starting from pre-synthesized (co)polymers. Due to the
- monomers and CD derivatives. The resulting triblock-copolyrotaxanes might be good stocks for the synthesis of highly elastic slide-ring gels and hydrogels. Due to the biocompatibility of the constituents and the ability of the polyrotaxanes to self-assemble, these materials might also be applicable for
Glycoscience@Synchrotron: Synchrotron radiation applied to structural glycoscience
Beilstein J. Org. Chem. 2017, 13, 1145–1167, doi:10.3762/bjoc.13.114
- methods of choice to investigate the states of soft-condensed materials, which include solutions and gels. Differences in wavelengths and scatterers can be used for combined measurements yielding supplemental information. Following the instrumental developments of light sources, SAXS has become a common
Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates
Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101
- spectrophotometer. 4-OT was assayed using 3a, as previously reported [19][20]. Protein concentrations were determined by the Waddell method [22]. 4-OT was analyzed using tricine SDS-PAGE on 15% gels [23]. All other proteins were analyzed using TRIS-glycine SDS-PAGE on 12% gels [24]. Gels were run on a Bio-Rad Mini
Investigation of the action of poly(ADP-ribose)-synthesising enzymes on NAD+ analogues
Beilstein J. Org. Chem. 2017, 13, 495–501, doi:10.3762/bjoc.13.49
- ARTD2 catalysed PAR production [24]. After the times indicated, copper-catalysed click conjugations to a fluorophore-containing azide were performed and the reactions were analysed by SDS PAGE. Then, fluorescent signals were detected and compared to the Coomassie Blue stained gels (Figure 2). Each
- analogue was additionally tested in a 1:1 mixture with natural NAD+ to explore their competitiveness against natural substrate and all gels contain controls without enzyme. A positive PARylation reaction is indicated by heterogeneous, polymer-modified proteins and/or the reduction of the ARTD band due to
- selected bulky, dye-modified NAD+ analogues 5 and 6, which were previously prepared by our group [21], in order to have a direct, fluorescent read-out. The outcome is summarised in Table 2 and the SDS PAGE gels obtained are depicted in Figure 4 and Supporting Information File 1, Figures S3 and S4. As shown
Adsorption of RNA on mineral surfaces and mineral precipitates
Beilstein J. Org. Chem. 2017, 13, 393–404, doi:10.3762/bjoc.13.42
- % formamide gel loading buffer for denaturing PAGE analysis (18%, 7 M urea). Gels were dried for 30 min at 80 °C before being exposed to a phosphorimager screen for quantitative autoradiography. Mineral identification with X-ray powder diffraction Identification of synthetic minerals was conducted with a
Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy
Beilstein J. Org. Chem. 2017, 13, 182–194, doi:10.3762/bjoc.13.21
- nanoporous polymer structure influences the delivery property of entrapped drugs [8]. In particular the transport properties of ibuprofen sodium salt (IbuNa) entrapped in CDNS polymer gels has been investigated by high resolution magic angle spinning (HR-MAS) NMR technique [9] as a paradigmatic case of an
- salt was prepared by dissolving 308 mg of IbuNa together with 68 mg of Na2CO3 in 5 mL of water. 3 mL of the solution (1) were then added to a weighted amount (400 mg) of CDNS polymer in both preparations. Homogeneous hydrogels were then obtained in 1 h. The measured pH of the gels was 6.5. The samples
A new class of organogelators based on triphenylmethyl derivatives of primary alcohols: hydrophobic interactions alone can mediate gelation
Beilstein J. Org. Chem. 2017, 13, 138–149, doi:10.3762/bjoc.13.17
- unit which may be further exploited in the design of small molecule based gelators. Keywords: hydrophobic interactions; organogelator; SEM; triphenylmethyl group; xerogel; Introduction Small organic molecules capable of forming gels are called low molecular weight gelators (LMWGs) [1][2][3]. These
- LMWGs can immobilize organic solvents (forming organogels) and water or aqueous solvents (forming hydrogels) under different experimental conditions. Gels, so formed are supramolecular in nature as they result from self-assembly of the gelator molecules through secondary interactions like H-bonding, π
- ][11][12][13]. They are being increasingly explored for a variety of uses in the fields of materials science, biomedicines, environment science, etc. Hence, the discovery of new functional gelators continues to be an important focus of research worldwide. Since most gels are formed by non-covalent
Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA
Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128
- ) with barely visible traces of mono-polyamide conjugate (line 6, e). Lines 5d and 6d are visible by UV-shadowing bands of electrophoresis migration marker xylene cyanol that is absent in other gels. Mass-spectrometry analysis confirmed the identity of the products obtained (Table S3 in Supporting
Superstructures with cyclodextrins: chemistry and applications III
Beilstein J. Org. Chem. 2016, 12, 937–938, doi:10.3762/bjoc.12.91
- has been achieved in the synthesis of CD polyrotaxanes. The one-pot and one-step polyrotaxane synthesis of β-CDs was performed in aqueous solution by employing a click reaction [7] as well as by radical copolymerization [8]. Slide-ring gels, synthesized by the group of K. Ito through the crosslinking
My maize and blue brick road to physical organic chemistry in materials
Beilstein J. Org. Chem. 2016, 12, 229–238, doi:10.3762/bjoc.12.24
- perspective concludes with some predictions about where molecular gels, as well as my personal and professional life, are headed. Keywords: molecular gel; organic chemistry; organic materials; self-assembly; supramolecular chemistry; Review One of my earliest memories involves pouring water down our
- hour while I attended a seminar; when I returned, the reaction mixture had formed a gel. In the end, we hypothesized that faster stirring disrupted more supramolecular aggregates, providing additional reactive sites for the alkylation, thereby accelerating the rate. As I read more about gels and other
- explained by through-space interactions [15]. Steven, who is now an associate professor at Texas A&M University, is changing the way we understand π stacking, XH/π, and ion/π interactions in organic systems [16][17][18][19][20]. During my postdoctoral studies, I remained fascinated with gels and was
Urethane tetrathiafulvalene derivatives: synthesis, self-assembly and electrochemical properties
Beilstein J. Org. Chem. 2015, 11, 2343–2349, doi:10.3762/bjoc.11.255
- by 1H NMR, 13C NMR, and EIMS. Self-assembly and SEM investigation of T1 and T2 The studies showed that T1 and T2 gels were not formed in several common solvents such as hexane, chloroform, dichloromethane, tetrahydrofuran, toluene, diethyl ether, acetone, dimethylformamide, ethanol, methanol and
Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels
Beilstein J. Org. Chem. 2015, 11, 2194–2201, doi:10.3762/bjoc.11.238
- silica. Small-angle X-ray scattering revealed that the homogeneous distribution of silica nanoparticles in solution was maintained in the gel state. Such homogeneous nanocomposite gels were obtained with at least 30 wt % silica content, and the Young’s modulus increased with silica content. Gelation did
- not occur without silica. This suggests that the silica nanoparticles behave as cross-linkers. Viscoelastic measurements of the nanocomposite gels showed no stress relaxation regardless of the silica content for <20% compression strain, indicating an infinite stable network without physical cross
- -links that have finite lifetime. On the other hand, the infinite network exhibited an abnormally low Young’s modulus, ~1 kPa, which is not explainable by traditional rubber theory. In addition, the composite gels were tough enough to completely maintain the network structure under 80% compression strain
Synthesis, antimicrobial and cytotoxicity evaluation of new cholesterol congeners
Beilstein J. Org. Chem. 2015, 11, 1922–1932, doi:10.3762/bjoc.11.208
- their immunostimulant activities [21]. Finally, the ability of cholesterol derivatives to self-assembly and gelation as supramolecular gels was reviewed [22]. They are beneficially applicable in materials science, reaction media, sensing and responsive materials, energy supply, biomedicine, and tissue
Synthesis of photoresponsive cholesterol-based azobenzene organogels: dependence on different spacer lengths
Beilstein J. Org. Chem. 2015, 11, 1089–1095, doi:10.3762/bjoc.11.122
- role in the gelation. Compound M6 is the only one that can gelate in ethanol, isopropanol and 1-butanol and the reversible gel–sol transitions are also investigated. To obtain visual insight into the microstructure of the gels, the typical structures of the xerogels were studied by SEM. Morphologies of
- have been utilized in supramolecular systems [19]. Examples of several cholesterol-linked azobenzenes with gel–sol reversible changes also have been studied [20][21][22][23]. R. Zentel found that the photoinduced reversible gel–sol changes between isotropic and anisotropic gels of a class of
- semicarbazide–azobenzene-based gelators [24]. A new multistimuli photoresponsive organogel containing azobenzene groups was designed and studied by D. Zhu and his co-workers [25]. Q. Zhang synthesized a series of new symmetric dicholesterol-linked gelators [26]. Upon UV–vis irradiation of the gels, a reversible
Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS
Beilstein J. Org. Chem. 2015, 11, 514–523, doi:10.3762/bjoc.11.58
- technology and allows the potential cooperative effects to be exploited within chromatographic applications by grafting to silica gels. Further, silicon dioxide surfaces in the form of quartz and glass allow the detection and monitoring of binding events by optical techniques such as fluorescence
Release of β-galactosidase from poloxamine/α-cyclodextrin hydrogels
Beilstein J. Org. Chem. 2014, 10, 3127–3135, doi:10.3762/bjoc.10.330
- available source of calcium and protein. In this work, gels obtained by complexation of Tetronic 90R4 with α-cyclodextrin loaded with β-galactosidase are proposed as a way to administer the enzyme immediately before or with the lactose-containing meal. Both molecules are biocompatible, can form gels in situ
- , and show sustained erosion kinetics in aqueous media. The complex was characterized by FTIR that evidenced an inclusion complex between the polyethylene oxide block and α-cyclodextrin. The release profiles of β-galactosidase from two different matrices (gels and tablets) of the in situ hydrogels have
- are able to form host–guest complexes by the inclusion of hydrophobic molecules. Cyclodextrins also act as hosts in the formation of inclusion compounds with polymer chains through non-covalent interactions [10]. For instance, incorporation of 5% α-CD transforms dilute Tetronic solutions into gels
Synthesis and characterization of pH responsive D-glucosamine based molecular gelators
Beilstein J. Org. Chem. 2014, 10, 3111–3121, doi:10.3762/bjoc.10.328
- enhanced the gelation tendency for many derivatives. The introduction of the additional methoxy group on the phenyl ring led to low molecular weight gelators with a higher pH responsiveness. The resulting gels were stable at neutral pH values but degraded in an acidic environment. The release profiles of
- naproxen from the pH responsive gels were also analyzed under acidic and neutral conditions. Our findings are useful for the design of novel triggered release self-assembling systems and can provide an insight into the influence of the the structure on gelation. Keywords: glucosamine; hydrogelators
- referred to as supramolecular gelators or molecular gelators. They can form reversible gels in organic solvents, aqueous mixtures, and water. The gelation process is completely driven by weak intermolecular forces such as hydrogen bonding, π–π stacking, hydrophobic forces, and van der Waals forces. The
Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers
Beilstein J. Org. Chem. 2014, 10, 3007–3018, doi:10.3762/bjoc.10.319
- prepared either in well water-soluble form or as gels of high swelling. Two versatile synthetic strategies for introducing a fluorescent tag (rhodamine, fluorescein, nitrobenzofuran or coumarin) into the water-soluble epichlorohydrin branched cyclodextrin polymers were worked out and compared. The
- into polymeric structures behave differently from their monomeric counterparts [4][5][6]. Depending on the requirements of application both highly soluble and water-insoluble polymers (gels, resins) can be produced. Furthermore, the polymeric structure can constrain the rate of rotation of the CDs. The
Cyclodextrin–polysaccharide-based, in situ-gelled system for ocular antifungal delivery
Beilstein J. Org. Chem. 2014, 10, 2903–2911, doi:10.3762/bjoc.10.308
- from eye surface is essentially completed at around 90 s. Under these conditions, the ocular surface is in contact with high drug concentrations only for very short periods of time. For this reason, knowing the initial cytotoxicity is crucial. Bioadhesive formulations as ion-sensitive gels have a high
- vessels of the chorioallantoic membrane (CAM) was not observed. CDs, fluconazole and final gel formulations (0.65%, 0.75% and 0.82% gel with and without HPBCD) showed no irritation based on the obtained irritation score (IS) of zero for all of these compounds (Figure 5). Therefore, the gels and their
- per gram of CD, allowing for gels with lower proportions. Ion-sensitive hydrogels synthesized without HPBCDs incorporated a concentration of fluconazole of 0.2% which is limited by its low water solubility. Hence, the incorporation of HPBCDs allows for hydrogels with higher doses. In the present study
Self-assembled monolayers of shape-persistent macrocycles on graphite: interior design and conformational polymorphism
Beilstein J. Org. Chem. 2014, 10, 2774–2782, doi:10.3762/bjoc.10.294
- experimental resolution. Contrary to the different robustness of the tubular aggregates (gels) from these macrocycles (where the intraannular strands come into close contact) [22], no stability changes and no packing scheme changes for the 2D surface patterns are observed. Similar patterns with alike (porous
Anomalous diffusion of Ibuprofen in cyclodextrin nanosponge hydrogels: an HRMAS NMR study
Beilstein J. Org. Chem. 2014, 10, 2715–2723, doi:10.3762/bjoc.10.286
- (HRMAS) NMR spectroscopy. The mean square displacement (MSD) of IP in the gels was obtained by a pulsed field gradient spin echo (PGSE) NMR pulse sequence at different observation times td. The MSD is proportional to the observation time elevated to a scaling factor α. The α values define the normal
- in the polymeric framework. HRMAS NMR spectroscopy has become an extremely versatile technique that provides high resolution NMR data on heterogeneous suspensions [21], gels [22] and swellable solids [23]. The basic principle is simple and can be summarized as follows: the dramatic line broadening
- nanosponge gels. Conversely, significant doubling of selected aromatic and methyl protons of IP was reported to take place in the presence of monomeric β-CD in D2O solution, thus confirming, in that case, the formation of an inclusion complex and the chiral discrimination [28]. The absence of signal doubling
A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection
Beilstein J. Org. Chem. 2014, 10, 2470–2479, doi:10.3762/bjoc.10.258
- was emitted by NBD/DDY/catalase, which is probably due to very low fluorescence quantum yields reported for NBD derivatives of primary amines in water [39]. Furthermore, NBD (9) is not suitable for standard SDS-PAGE (12% gels) as the dye smears and therefore potentially covers fluorescent signals of
Expanding the scope of cyclopropene reporters for the detection of metabolically engineered glycoproteins by Diels–Alder reactions
Beilstein J. Org. Chem. 2014, 10, 2235–2242, doi:10.3762/bjoc.10.232
- the cleared supernatant to a final concentration of 150 µM. The samples were incubated for 90 min at rt, 3× SDS-sample buffer was added, and the sample was boiled at 90 °C for 15 min. Proteins were separated by SDS-polyacrylamide gel electrophoresis using 10% polyacrylamide gels and transferred to
Supercritical carbon dioxide: a solvent like no other
Beilstein J. Org. Chem. 2014, 10, 1878–1895, doi:10.3762/bjoc.10.196
- structure and affect viscosity. Examples of self-assembly structures that are commonly used to enhance viscosity include ellipsoid and rod-like micelles, worm and lamellar structures, bicontinuous phases and also the formation of gels [32][46][49][50][93][94][95]. Polymeric CO2 viscosifiers: Several
- ~5 orders of magnitude with phenol addition being as low as 0.1 mol dm−3 [93][104][108]. Particularly stiff gels were formed when the surfactant concentration and the phenol concentration were close to 1:1 and softening appeared when the surfactant:phenol ratio moved to around ≥3:1 or ≤1:3; the gels
Carbohydrate PEGylation, an approach to improve pharmacological potency
Beilstein J. Org. Chem. 2014, 10, 1433–1444, doi:10.3762/bjoc.10.147
- PEGylation. Hydrogels with supramolecular structures have been obtained by inclusion complexation of the PEG grafted dextrans with α-cyclodextrins. The unique thermoreversible sol-transition properties of the gels were considered interesting for drug delivery applications [65]. Conclusion The advantage of
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