Artigos de revistas: "Dendrons"

1

Hofacker, Amanda L., e Jon R. Parquette. "Amplification of local chirality within a folded dendrimer. An intramolecular ‘sergeants and soldiers’ experiment". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 466, n.º 2117 (26 de agosto de 2009): 1469–87. http://dx.doi.org/10.1098/rspa.2009.0274.

Texto completo da fonte

Resumo:

A series of pyridine-2,6-dicarboxamide dendrons having varying proportions of chiral and achiral termini have been prepared. Circular dichroism and X-ray crystallographic studies indicate that these folded dendrons propagate terminal chirality via a ‘sergeants and soldiers’ process. The extent of chiral amplification shows a dependence on dendron generation, but also is affected by the relative positioning of the chiral termini at the periphery of the dendron. Analysis of the crystal structures of the G1 dendrons, 4a – 6a , reveals chain–chain and chain–dendron conformational communication, which is likely to be responsible for the chiral amplification observed in solution.

Estilos ABNT, Harvard, Vancouver, APA, etc.

2

Zhao, Yanna, Jing Zhao, Chunying Hao, Meihua Han, Mincan Wang, Yifei Guo e Xiangtao Wang. "Self-assembled thermosensitive nanoparticles based on oligoethylene glycol dendron conjugated doxorubicin: preparation, and efficient delivery of free doxorubicin". RSC Advances 6, n.º 4 (2016): 2602–10. http://dx.doi.org/10.1039/c5ra22224a.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

3

Issa, Rahaf, Steve T. Meikle, Stuart L. James e Ian R. Cooper. "Use of Poly (ε-Lysine) Dendrons: A Strategy Targeting Bacterial Quorum Sensing and Biofilm Formation". Conference Papers in Science 2014 (11 de março de 2014): 1–8. http://dx.doi.org/10.1155/2014/572828.

Texto completo da fonte

Resumo:

Pseudomonas aeruginosa is recognised as a major aetiological agent of nosocomial infections, which are associated with multiple-antibiotic resistance. Among many of its important virulence factors is its ability to form biofilms on the surfaces of implantable medical devices and to produce toxic metabolites, pyocyanin, via an intercellular cell density-dependent signalling system of communication. In this study, poly (ε-lysine) dendrons composed of increasingly branching generations were synthesised, characterised, and examined for their effects on virulence factor production in P. aeruginosa. The results show that these hyperbranched poly (ε-lysine) dendrons, in particular the 3rd generation, can increase the efficacy of a conventional antibiotic, ciprofloxacin, and reduce pyocyanin production, with marginal effects on the rate of bacterial replication, suggesting that the observed effects are not due to dendron toxicity. Furthermore, dendron and ciprofloxacin coadministration was identified as the most effective strategy which highlights the potential of peptide-based dendrons as quorum sensing inhibitors.

Estilos ABNT, Harvard, Vancouver, APA, etc.

4

Barkley, Deborah A., Sang Uk Han, Tadanori Koga e Jonathan G. Rudick. "Peptide–dendron hybrids that adopt sequence-encoded β-sheet conformations". Polymer Chemistry 9, n.º 40 (2018): 4994–5001. http://dx.doi.org/10.1039/c8py00882e.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

5

Meyhoff, Ulrich, Ulla Riber e Ulrik Boas. "Convergent synthesis of degradable dendrons based on l-malic acid". New Journal of Chemistry 39, n.º 2 (2015): 1161–71. http://dx.doi.org/10.1039/c4nj01156b.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

6

Shi, Da, Dinh-Vu Nguyen, Mounir Maaloum, Jean-Louis Gallani, Delphine Felder-Flesch e Marie Pierre Krafft. "Interfacial Behavior of Oligo(Ethylene Glycol) Dendrons Spread Alone and in Combination with a Phospholipid as Langmuir Monolayers at the Air/Water Interface". Molecules 24, n.º 22 (14 de novembro de 2019): 4114. http://dx.doi.org/10.3390/molecules24224114.

Texto completo da fonte

Resumo:

Dendrons consisting of two phosphonate functions and three oligo(ethylene glycol) (OEG) chains grafted on a central phenoxyethylcarbamoylphenoxy group were synthesized and investigated as Langmuir monolayers at the surface of water. The OEG chain in the para position was grafted with a t-Bu end-group, a hydrocarbon chain, or a partially fluorinated chain. These dendrons are models of structurally related OEG dendrons that were found to significantly improve the stability of aqueous dispersions of iron oxide nanoparticles when grafted on their surface. Compression isotherms showed that all OEG dendrons formed liquid-expanded Langmuir monolayers at large molecular areas. Further compression led to a transition ascribed to the solubilization of the OEG chains in the aqueous phase. Brewster angle microscopy (BAM) provided evidence that the dendrons fitted with hydrocarbon chains formed liquid-expanded monolayers throughout compression, whilst those fitted with fluorinated end-groups formed crystalline-like domains, even at large molecular areas. Dimyristoylphosphatidylcholine and dendron molecules were partially miscible in monolayers. The deviations to ideality were larger for the dendrons fitted with a fluorocarbon end-group chain than for those fitted with a hydrocarbon chain. Brewster angle microscopy and atomic force microscopy supported the view that the dendrons were ejected from the phospholipid monolayer during the OEG conformational transition and formed crystalline domains on the surface of the monolayer.

Estilos ABNT, Harvard, Vancouver, APA, etc.

7

Enciso, Alan E., Giovanni Doni, Riccardo Nifosì, Ferruccio Palazzesi, Roberto Gonzalez, Amy A. Ellsworth, Jeffery L. Coffer et al. "Facile synthesis of stable, water soluble, dendron-coated gold nanoparticles". Nanoscale 9, n.º 9 (2017): 3128–32. http://dx.doi.org/10.1039/c6nr09679d.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

8

Hameau, Aurélien, Sabine Fuchs, Régis Laurent, Jean-Pierre Majoral e Anne-Marie Caminade. "Synthesis of dye/fluorescent functionalized dendrons based on cyclotriphosphazene". Beilstein Journal of Organic Chemistry 7 (28 de novembro de 2011): 1577–83. http://dx.doi.org/10.3762/bjoc.7.186.

Texto completo da fonte

Resumo:

Functionalized phenols based on tyramine were synthesized in order to be selectively grafted on to hexachlorocyclotriphosphazene, affording a variety of functionalized dendrons of type AB5. The B functions comprised fluorescent groups (dansyl) or dyes (dabsyl), whereas the A function was provided by either an aldehyde or an amine. The characterization of these dendrons is reported. An unexpected behaviour of a fluorescent and water-soluble dendron based on dansyl groups in mixtures of dioxane/water was observed.

Estilos ABNT, Harvard, Vancouver, APA, etc.

9

Lu, Yao-Chih, Yu-Tsz Hsu, Tsung-Yen Yang, I.-Chun Liou, Sheng-Wei Wang, Po-Chia Huang, Jey-Jau Lee, Long-Li Lai e Hsiu-Fu Hsu. "Converting non-Mesogenic to Mesogenic Stacking of Amino-s-Triazine-Based Dendrons with p-CN Phenyl Unit by Eliminating Peripheral Dipole". Nanomaterials 12, n.º 2 (6 de janeiro de 2022): 185. http://dx.doi.org/10.3390/nano12020185.

Texto completo da fonte

Resumo:

Three new amino-s-triazine-based dendrons, 1a, 1b, and 1c, containing an aryl-CN moiety in the dendritic skeleton were prepared in 72–81% yields (1a: R1 = − N(n-C8H17)2, R2 = n-OC8H17, 1b: R1 = R2 = − N(n-C8H17)2, 1c: R1 = − N(n-C8H17)2, R2 = − N(n-C4H9)2). Dendrons 1a with N(n-C8H17)2 and n-OC8H17 peripheral substituents, surprisingly, did not show any mesogenic phase during the thermal process. However, non-mesogenic 1a can be converted to mesogenic 1b or 1c by eliminating the peripheral dipole arising from the alkoxy substituent; dendron 1b only comprising the same N(n-C8H17)2 peripheral groups showed a ~25 °C mesogenic range on heating and ~108 °C mesogenic range on cooling. In contrast, dendron 1c possessing different N(n-CmH2m+1)2 (m = 8 versus m = 4) peripheral units, having similar stacking as 1b, exhibited a columnar phase on thermal treatment, but its mesogenic range (~9 and ~66 °C on heating and cooling, respectively) was much narrower than that of 1b, attributed to 1c’s less flexible alkyl chains in the peripheral part of dendron. Dendron 1a with the alkoxy substituent in the peripheral skeleton, creating additional dipole correspondingly, thus, leads to the dendritic molecules having a non-mesogenic stacking. Without the peripheral dipole for intermolecular side-by-side interaction, dendrons 1b and 1c exhibit a columnar phase on thermal treatment because of the vibration from the peripheral alkyl chain.

Estilos ABNT, Harvard, Vancouver, APA, etc.

10

Peyret, Ariane, John F. Trant, Colin V. Bonduelle, Khalid Ferji, Namrata Jain, Sebastien Lecommandoux e Elizabeth R. Gillies. "Synthetic glycopolypeptides: synthesis and self-assembly of poly(γ-benzyl-l-glutamate)-glycosylated dendron hybrids". Polymer Chemistry 6, n.º 45 (2015): 7902–12. http://dx.doi.org/10.1039/c5py01060h.

Texto completo da fonte

Resumo:

Polyester dendrons with peripheral α-galactose moieties were synthesized and coupled to poly(γ-benzyl-l-glutamate) to afford amphiphilic linear-dendron hybrid glycopolypeptides that self-assembled in water.

Estilos ABNT, Harvard, Vancouver, APA, etc.

11

BAEK, NAM SEOB, YONG HEE KIM e HWAN KYU KIM. "RECENT PROGRESS IN ERBIUM(III)-CORED COMPLEXES BASED ON DENDRITIC LIGANDS FOR ADVANCED PHOTONICS APPLICATIONS". Journal of Nonlinear Optical Physics & Materials 15, n.º 03 (setembro de 2006): 369–79. http://dx.doi.org/10.1142/s0218863506003360.

Texto completo da fonte

Resumo:

We present that the stable and inert Er(III) -encapsulated complexes based on naphthalene and anthracene ligands bearing a Fréchet aryl-ether dendron exhibit much stronger near-IR emission bands bands at 1530 nm, originated from the 4f–4f electronic transition of the first excited state (4 I 13/2) to the ground state (4 I 15/2) of the partially-filled 4f shell. A strong decrease in the fluorescence of G n-aryl ether dendron (n = 0 or 2) is accompanied by strongly increasing the fluorescence intensity of the luminescent anthracene or naphthalene ligand with the generation number of the dendrons. The strong decrease of fluorescence intensity of luminescent ligand such as naphthalene and anthracene units is accompanied by strongly increasing the near infrared (IR) emission of the Er 3+ ions in Er(III) -encapsulated complexes. It could be attributed to the efficient energy transfer process occurring between the aryl-ether dendron and anthracene moiety as well as between dendritic anthracene ligand and Er 3+ ion. Thus, the emission intensity of the lanthanide complexes, upon photoexcitation of aryl-ether dendrons at 290 nm, was dramatically enhanced with an increase in the generation number n of dendrons, due to the site-isolation and light-harvesting effects. In addition, Er 3+-[ G 2- An ]3(terpy) exhibits the stronger PL intensity than Er 3+-[ G 2- Na ]3(terpy)) by 2.5 times, upon photoexcitation of aryl-ether dendrons at 290 nm. It may be due to the fact that the anthracene ligand in Er 3+-[ G 2- An ]3(terpy)) has higher spectral overlap integral (J) value than the naphthalene ligand in Er 3+-[ G 2- Na ]3(terpy) by 1.5 times. Surprisingly, all Er(III) -cored dendrimer complexes have excellent thermal- and photo-stability as well as good solubility.

Estilos ABNT, Harvard, Vancouver, APA, etc.

12

Bender, Timothy P., Yu Qi, Pierre Desjardins e Zhi Yuan Wang. "Article". Canadian Journal of Chemistry 77, n.º 8 (1 de agosto de 1999): 1444–52. http://dx.doi.org/10.1139/v99-147.

Texto completo da fonte

Resumo:

Herein, we describe the synthesis, characterization, and electrochemical behavior of dendritic aryl imides derived from a core compound 3,12-dinitro-5,6,9,10-tetrahydro[5]helicene-7,8-dicarboxylic anhydride (3). Compound 3 is an AX2 type system (where X is a masked or protected group), possesses a well-defined spatial orientation, is conformationally rigid, and contains a conjugated o-terphenyl moiety as part of its molecular structure. This compound is used as a building block in the construction of dendritic aryl imides using a divergent synthetic approach. Dendrons from generations one through three were synthesized, and their identities were confirmed. A comparison of the properties of the dendrons, several model compounds, and a linear oligoimide, all containing either the tetrahydro[5]helicene or o-terphenyl units, has been made. There are differences in their hydrodynamic volume, glass transition temperature, and electrochemical behaviour. All dendrons are electrochemically active and exhibit well-defined and reversible redox cycles. Furthermore, all dendrons are fluorescent, and the intensity of the fluorescent emission is dependent on the generation of the dendron.Key words: dendrimer, dendron, electrochemistry, helicene, tetrahydro[5]helicene.

Estilos ABNT, Harvard, Vancouver, APA, etc.

13

Tulli, Ludovico G., Daniela Miranda, Cameron C. Lee, Yang Sullivan, Robert Grotzfeld, Gregory Hollingworth, Rainer Kneuer e Alexei S. Karpov. "Modular synthesis and modification of novel bifunctional dendrons". Organic & Biomolecular Chemistry 17, n.º 11 (2019): 2906–12. http://dx.doi.org/10.1039/c8ob02988a.

Texto completo da fonte

Resumo:

The modular synthesis of two generations of highly branched bifunctional dendrons is reported. The first generation dendron–antibody conjugate is shown to selectively detect CD4⁺ T cells in the PBMC culture.

Estilos ABNT, Harvard, Vancouver, APA, etc.

14

Thoma, Janine L., Stuart A. McNelles, Alex Adronov e Jean Duhamel. "Direct Measure of the Local Concentration of Pyrenyl Groups in Pyrene-Labeled Dendrons Derived from the Rate of Fluorescence Collisional Quenching". Polymers 12, n.º 12 (5 de dezembro de 2020): 2919. http://dx.doi.org/10.3390/polym12122919.

Texto completo da fonte

Resumo:

The model-free analysis (MFA) was applied to measure the average rate constant (<k>) for pyrene excimer formation (PEF) in a series of pyrene-labeled dendrons referred to as Pyx-G(N), where x (= 2N) is the number of pyrenyl labels born by a dendron of generation N ranging from 1 to 6. <k> was measured in four different solvents, namely tetrahydrofuran (THF), toluene, N,N-dimethylformamide (DMF), and dimethylsulfoxide (DMSO). <k> was found to increase linearly with increasing local pyrene concentration ([Py]loc), where [Py]loc had been determined mathematically for the Pyx-G(N) dendrons. The slope of each straight line changed with the nature of the solvent and represented kdiff, the bimolecular rate constant for PEF. kdiff depended on the solvent viscosity (η) and the probability (p) for PEF upon encounter between an excited and a ground-state pyrene. In a same solvent, kdiff for the Pyx-G(N) dendrons was about 360 ± 30 times smaller than kdiff obtained for ethyl 4-(1-pyrene)butyrate (PyBE), a pyrene model compound similar to the pyrene derivative used to label the dendrons. The massive decrease in kdiff observed for the Pyx-G(N) samples reflected the massive loss in mobility experienced by the pyrenyl labels after being covalently attached onto a macromolecule compared to freely diffusing PyBE. Interestingly, the kdiff values obtained for the Pyx-G(N) dendrons and the PyBE model compound followed similar trends as a function of solvent, indicating that the difference in behavior between the kdiff values obtained in different solvents were merely due to the changes in the η and p values between the solvents. Normalizing the <k> values obtained with the Pyx-G(N) dendrons by the kdiff values obtained for PyBE in the same solvents accounted for changes in η and p, resulting in a master curve upon plotting <k>/(fdiff × kdiff) as a function of [Py]loc, where fdiff was introduced to account for some pyrene aggregation in the higher generation dendron (Py64-G(6)). This result demonstrates that <k> represents a direct measure of [Py]loc in pyrene-labeled macromolecules.

Estilos ABNT, Harvard, Vancouver, APA, etc.

15

Suty, Simon, Veronika Oravczova, Zuzana Garaiova, Veronika Subjakova, Maksim Ionov, Dzmitry Shcharbin, Zuzana Simonikova et al. "Blood Compatibility of Amphiphilic Phosphorous Dendrons—Prospective Drug Nanocarriers". Biomedicines 9, n.º 11 (12 de novembro de 2021): 1672. http://dx.doi.org/10.3390/biomedicines9111672.

Texto completo da fonte

Resumo:

Dendrons are branched synthetic polymers suitable for preparation of nanosized drug delivery systems. Their interactions with biological systems are mainly predetermined by their chemical structure, terminal groups, surface charge, and the number of branched layers (generation). Any new compound intended to be used, alone or in combination, for medical purposes in humans must be compatible with blood. This study combined results from in vitro experiments on human blood and from laboratory experiments designed to assess the effect of amphiphilic phosphorous dendrons on blood components and model membranes, and to examine the presence and nature of interactions leading to a potential safety concern. The changes in hematological and coagulation parameters upon the addition of dendrons in the concentration range of 2–10 µM were monitored. We found that only the combination of higher concentration and higher generation of the dendron affected the selected clinically relevant parameters: it significantly decreased platelet count and plateletcrit, shortened thrombin time, and increased activated partial thromboplastin time. At the same time, occasional small-sized platelet clumps in blood films under the light microscope were observed. We further investigated aggregation propensity of the positively charged dendrons in model conditions using zwitterionic and negatively charged liposomes. The observed changes in size and zeta potential indicated the electrostatic nature of the interaction. Overall, we proved that the low-generation amphiphilic phosphorous dendrons were compatible with blood within the studied concentration range. However, interactions between high-generation dendrons at bulk concentrations above 10 µM and platelets and/or clotting factors cannot be excluded.

Estilos ABNT, Harvard, Vancouver, APA, etc.

16

Veliskova, Martina, Milan Zvarik, Simon Suty, Juraj Jacko, Patrick Mydla, Katarina Cechova, Daniela Dzubinska et al. "In Vitro Interactions of Amphiphilic Phosphorous Dendrons with Liposomes and Exosomes—Implications for Blood Viscosity Changes". Pharmaceutics 14, n.º 8 (30 de julho de 2022): 1596. http://dx.doi.org/10.3390/pharmaceutics14081596.

Texto completo da fonte

Resumo:

Drug delivery by dendron-based nanoparticles is widely studied due to their ability to encapsulate or bind different ligands. For medical purposes, it is necessary (even if not sufficient) for these nanostructures to be compatible with blood. We studied the interaction of amphiphilic dendrons with blood samples from healthy volunteers using standard laboratory methods and rheological measurements. We did not observe clinically relevant abnormalities, but we found a concentration-dependent increase in whole blood viscosity, higher in males, presumably due to the formation of aggregates. To characterize the nature of the interactions among blood components and dendrons, we performed experiments on the liposomes and exosomes as models of biological membranes. Based on results obtained using diverse biophysical methods, we conclude that the interactions were of electrostatic nature. Overall, we have confirmed a concentration-dependent effect of dendrons on membrane systems, while the effect of generation was ambiguous. At higher dendron concentrations, the structure of membranes became disturbed, and membranes were prone to forming bigger aggregates, as visualized by SEM. This might have implications for blood flow disturbances when used in vivo. We propose to introduce blood viscosity measurements in early stages of investigation as they can help to optimize drug-like properties of potential drug carriers.

Estilos ABNT, Harvard, Vancouver, APA, etc.

17

Prados, Isabel M., Andrea Barrios-Gumiel, Francisco J. de la Mata, M. Luisa Marina e M. Concepción García. "Magnetic nanoparticles coated with carboxylate-terminated carbosilane dendrons as a reusable and green approach to extract/purify proteins". Analytical and Bioanalytical Chemistry 414, n.º 4 (9 de dezembro de 2021): 1677–89. http://dx.doi.org/10.1007/s00216-021-03794-7.

Texto completo da fonte

Resumo:

AbstractExtraction/purification of proteins, at both analytical and industrial levels, is a limiting step that usually requires the use of organic solvents and involves tedious work and a high cost. This work proposes a more sustainable alternative based on the use of magnetic nanoparticles (MNPs) coated with carboxylate-terminated carbosilane dendrons. MNPs coated with first- and second-generation carbosilane dendrons and bare MNPs were employed for the extraction of proteins with different molecular weights and charges. Interaction of proteins with MNPs significantly varied with the pH, the protein, and the dendron generation (different sizes and number of charges in the periphery). Optimal dendron:protein molar ratios and suitable conditions for disrupting interactions after protein extraction were also researched. Second-generation dendron-coated MNPs showed 100% retention capability for all proteins when using acidic conditions. They were reused without losing magnetism or interaction capacity after a disruption of protein-dendron interactions with 0.2% SDS at 100 °C for 10 min. The capacity of dendron-coated MNPs was successfully applied to the recovery/purification of proteins from two food by-products, olive seeds and cheese whey. Graphical abstract

Estilos ABNT, Harvard, Vancouver, APA, etc.

18

Ryzhkov, Aleksei I., Fedor V. Drozdov, Georgij V. Cherkaev e Aziz M. Muzafarov. "Synthesis of Carbosilane and Carbosilane-Siloxane Dendrons Based on Limonene". Polymers 14, n.º 16 (12 de agosto de 2022): 3279. http://dx.doi.org/10.3390/polym14163279.

Texto completo da fonte

Resumo:

In this work, carbosilane dendrons of the first, second, and third generations were obtained on the basis of a natural terpenoid, limonene. Previously, we have shown the possibility of selective hydrosilylation and hydrothiolation of limonene. It is proved that during hydrosilylation, only the isoprenyl double bond reacts, while the cyclohexene double bond does not undergo into the hydrosilylation reaction. However, the cyclohexene double bond reacts by hydrothiolation. This selectivity makes it possible to use limonene as a dendron growth center, while maintaining a useful function—a double bond at the focal point. Thus, the sequence of hydrosilylation and Grignard reactions based on limonene formed carbosilane dendrons. After that, the end groups were blocked by heptamethyltrisiloxane or butyllithium. The obtained substances were characterized using NMR spectroscopy, elemental analysis and GPC. Thus, the proposed methodology for the synthesis of carbosilane dendrons based on the natural terpenoid limonene opens up wide possibilities for obtaining various macromolecules: dendrimers, Janus dendrimers, dendronized polymers, and macroinitiators.

Estilos ABNT, Harvard, Vancouver, APA, etc.

19

García-Peña, Nidia G., Anne-Marie Caminade, Armelle Ouali, Rocío Redón e Cédric-Olivier Turrin. "Solventless synthesis of Ru(0) composites stabilized with polyphosphorhydrazone (PPH) dendrons and their use in catalysis". RSC Advances 6, n.º 69 (2016): 64557–67. http://dx.doi.org/10.1039/c6ra13709a.

Texto completo da fonte

Resumo:

Ruthenium is in the air: small Ru NPs are obtained by milling RuCl₃, NaBH₄ and polyphosphorhydrazone dendrons under air. The whole dendron structure is involved in the stabilization process. These NPs catalyze the selective hydrogenation of styrene.

Estilos ABNT, Harvard, Vancouver, APA, etc.

20

Flores-Rojas, Guadalupe G., Mark E. Martínez-Klimov, Omar G. Morales-Saavedra e Marcos Martínez-García. "Porphyrin Dendrimers". MRS Proceedings 1479 (2012): 45–50. http://dx.doi.org/10.1557/opl.2012.1596.

Texto completo da fonte

Resumo:

ABSTRACTDendrons with a porphyrin core and π-conjugated dendron branches have been synthesized and characterized. The dendrons showed an all trans configuration. Cubic non-linear optical behavior of the styryl and porphyrin-containing dendrimers was tested viaZ-Scan measurements in spin-coated film samples.

Estilos ABNT, Harvard, Vancouver, APA, etc.

21

Kwan, Chak-Shing, Watson K. W. Ho, Yanyan Chen, Zongwei Cai e Ken Cham-Fai Leung. "Synthesis of Functional Building Blocks for Type III-B Rotaxane Dendrimer". Polymers 13, n.º 22 (12 de novembro de 2021): 3909. http://dx.doi.org/10.3390/polym13223909.

Texto completo da fonte

Resumo:

Second-generation type III-B rotaxane dendrons, equipped with succinimide and acetylene functional groups, were synthesized successfully and characterized by NMR spectroscopy and mass spectrometry. A cell viability study of a dendron with a normal cell line of L929 fibroblast cells revealed no obvious cytotoxicity at a range of 5 to 100 μM. The nontoxic properties of the sophisticated rotaxane dendron building blocks provided a choice of bio-compatible macromolecular machines that could be potentially developed into polymeric materials.

Estilos ABNT, Harvard, Vancouver, APA, etc.

22

Dockery, Lance T., e Marie-Christine Daniel. "Targeted Doxorubicin-Loaded Dendronized Gold Nanoparticles". Pharmaceutics 15, n.º 8 (9 de agosto de 2023): 2103. http://dx.doi.org/10.3390/pharmaceutics15082103.

Texto completo da fonte

Resumo:

Dendronized nanoparticles, also called nanoparticle-cored dendrimers, combine the advantages of nanoparticles and dendrimers. These very stable and polyvalent nanoparticles can be used for diverse applications. One such application is drug delivery, because the dendrons can enhance the density of the payload. In this report, we describe the design of multifunctional gold nanoparticles (AuNPs) coated with poly(propylene imine) (PPI) dendrons that contain both prostate cancer active targeting and chemotherapeutic drugs. The PPI dendron is a good candidate for the design of drug delivery vehicles because of its ability to induce a proton sponge effect that will enhance lysosomal escape and intracellular therapeutic delivery. The chemotherapeutic drug used is doxorubicin (DOX), and it was linked to the dendron through a hydrazone acid-sensitive bond. Subsequent acidification of the AuNP system to a pH of 4–5 resulted in the release of 140 DOX drugs per nanoparticles. In addition, the PPI dendron was conjugated via “click” chemistry to an EphA2-targeting antibody fragment that has been shown to target prostate cancer cells. In vitro cell viability assays revealed an IC50 of 0.9 nM for the targeted DOX-bearing AuNPs after 48 h incubation with PC3 cells. These results are very promising upon optimization of the system.

Estilos ABNT, Harvard, Vancouver, APA, etc.

23

Ulloa, José Antonio, Joaquín Barberá e José Luis Serrano. "Gold Nanoparticles Modification with Liquid Crystalline Polybenzylic Dendrons via 1,3-Dipolar Cycloaddition". Nanomaterials 12, n.º 22 (16 de novembro de 2022): 4026. http://dx.doi.org/10.3390/nano12224026.

Texto completo da fonte

Resumo:

A series of six polybenzylic dendrons with an alkynyl focal point were synthesized for their incorporation to gold nanoparticles. Five of these compounds showed columnar mesomorphism in a wide range of temperatures. These dendrons were reacted with gold nanoparticles stabilized with a combination of a dodecanethiol and 11-azidoundecane-1-thiol. The azido group of the last compound allowed the functionalization of the nanoparticles with the six polybenzylic dendrons by 1,3-dipolar cycloaddition between their alkynyl groups and the terminal azido groups of the thiols. A high efficiency of the cycloaddition process (47–69%) was confirmed by several experimental techniques and no decomposition or aggregation phenomena were detected in the dendron-coated nanoparticles. The involved mechanism and the resulting percentage composition of the final materials are discussed. The results of the ulterior growth of the nanoparticles by thermal treatment are influenced by the size and the shape of the dendron and the temperature of the process. The structures of the final nanoparticles were investigated by TEM, DSC, TGA, NMR and UV-Vis spectroscopy. These nanoparticles do not show liquid crystal properties. However, a melting process between a crystalline and a fluid phase is observed. In the solid phase, the nanomaterials prepared show a short-range interaction between nanoparticles with a 2D local hexagonal order. A near-field effect was observed in the UV-vis spectra by coupling of different surface plasmon resonance bands (SPR) probably due to the short-range interactions. The main novelty of this work lies in the scarcity of previous studies of gold nanoparticles coated with dendrons forming themselves columnar mesophases. Most of the studies reported in the literature deal with gold nanoparticles coated with calamitic mesogens. Additionally, the effect of the thermal treatment, which in a previous paper was shown to increase the mean size of the nanoparticles without increasing their size polydispersity, has been studied in these materials.

Estilos ABNT, Harvard, Vancouver, APA, etc.

24

Poudel, Dhruba P., e Richard T. Taylor. "Thiol-Ene Click-Inspired Late-Stage Modification of Long-Chain Polyurethane Dendrimers". Reactions 3, n.º 1 (22 de dezembro de 2021): 12–29. http://dx.doi.org/10.3390/reactions3010002.

Texto completo da fonte

Resumo:

The construction of well-defined polyurethane dendrimers is challenging due to the high reactivity of externally added or in situ formed isocyanates leading to the formation of side products. With a primary focus of dendrimer research being the interaction of the periphery and the core, we report the synthesis of a common polyurethane dendron, which allows for the late-stage variation of both the periphery and the core. The periphery can be varied simply by installing a clickable unit in the dendron and then attaching to the core and vice-versa. Thus, a common dendron allows for varying periphery and core in the final two steps. To accomplish this, a protecting group-free, one-pot multicomponent Curtius reaction was utilized to afford a robust and versatile AB2 type polyurethane dendron employing commercially available simple molecules: 5-hydroxyisophthalic acid, 11-bromoundecanol, and 4-penten-1-ol. Subsequent late-stage modifications of either dendrons or dendrimers via a thiol-ene click reaction gave surface-functionalized alternating aromatic-aliphatic polyurethane homodendrimers to generation-three (G3). The dendrons and the dendrimers were characterized by NMR, mass spectrometry, and FT-IR analysis. A bifunctional AB2 type dendritic monomer demonstrated this approach’s versatility that can either undergo a thiol-ene click or attachment to the core. This approach enables the incorporation of functionalities at the periphery and the core that may not withstand the dendrimer growth for the synthesis of polyurethane dendrimers and other dendritic macromolecules.

Estilos ABNT, Harvard, Vancouver, APA, etc.

25

Meikle, S. T., G. Bianchi, G. Olivier e M. Santin. "Osteoconductive phosphoserine-modified poly(ε-lysine) dendrons: synthesis, titanium oxide surface functionalization and response of osteoblast-like cell lines". Journal of The Royal Society Interface 10, n.º 79 (6 de fevereiro de 2013): 20120765. http://dx.doi.org/10.1098/rsif.2012.0765.

Texto completo da fonte

Resumo:

The lack of direct bonding between the surface of an implant and the mineralized bony tissue is among the main causes of aseptic loosening in titanium-based implants. Surface etching and ceramic coatings have led to improved osteointegration, but their clinical performance is still limited either by partial bonding or by coating delamination. In this work, a solid-phase synthesis method has been optimized to produce poly(ε-lysine) dendrons, the outermost branching generation of which is functionalized by phosphoserine (PS), a known catalyst of the biomineralization process. The dendrons were deposited onto etched titanium oxide surfaces as a near-to-monolayer film able to induce the formation of a homogeneous calcium phosphate phase in a simulated body fluid over 3 days. The dendron films also stimulated MG63 and SAOS-2 osteoblast-like cells to proliferate at a rate significantly higher than etched titanium, with SAOS-2 also showing a higher degree of differentiation over 14 days. PS-tethered dendron films were not affected by various sterilization methods and UV treatment appeared to improve the cell substrate potential of these films, thus suggesting their potential as a surface functionalization method for bone implants.

Estilos ABNT, Harvard, Vancouver, APA, etc.

26

Song, Li Yun, Shun Jin Peng e Yang Shu. "Preparation of a Novel Functionated POSS Nano-Particle Bearing the Perfluoro Aryl Ether Dendron". Advanced Materials Research 148-149 (outubro de 2010): 1212–16. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.1212.

Texto completo da fonte

Resumo:

In this paper, the perfluoro aryl ether dendrons were synthesized by mesylate reaction, and using the dendron as a modifier to prepare a novel fluorinated polyhedral oligomeric silsesquioxane ( F-POSS) nano-particle bearing this fluorine-containing dendron. In this approach, the Williamson ether synthesis technique was used as the generation enhancement step. Second generation perfluorobenzyl alcohol dendron was obtained from active mesylated precursors. This mesylate actiation technology has the advantage of short reaction times in the subsequent steps and avoids chromatographic purifiction. Second genenriation dendron was then built by repitition of Williamson ether synthesis reaction of mesylate derivative. It is possible for this new nano-particle to be used in the modification of polymer materials to make the durable superhydrophobic and oilphobic surface functional materials with excellent self-cleaning properties.

Estilos ABNT, Harvard, Vancouver, APA, etc.

27

Fuentes-Paniagua, Elena, José M. Hernández-Ros, Juan Soliveri, José L. Copa-Patiño, Rafael Gómez, Javier Sánchez-Nieves e F. Javier de la Mata. "Strategies for penicillin V dendronization with cationic carbosilane dendrons and study of antibacterial properties". Canadian Journal of Chemistry 95, n.º 9 (setembro de 2017): 927–34. http://dx.doi.org/10.1139/cjc-2017-0059.

Texto completo da fonte

Resumo:

Strategies to synthesize a cationic carbosilane dendron containing the antibiotic penicillin V potassium salt (PenVK) at the focal point are discussed. The preparation of such a compound requires the use of systems with no donor atoms such as N or S in their framework, because their presence favours the rupture of the penicillin β-lactam ring. The antibacterial activity of the new dendron containing ammonium groups, at the periphery, and the PenV moiety, at the focal point, against gram-positive Staphylococcus aureus strains was evaluated. These results were compared with those obtained for free PenVK, a related cationic dendron without a penicillin moiety at the focal point, and also compared with an equimolar mixture of this last dendron with free PenV. The data obtained indicate that, on one hand, the conjugation or interaction of PenV with cationic dendrons reduces its activity in comparison with free PenVK. On the other hand, the penicillin dendron is able to release the antibiotic in the presence of esterease, due to the breaking of the ester bond in this derivative.

Estilos ABNT, Harvard, Vancouver, APA, etc.

28

Terehova, M. M., V. M. Abashkin, V. A. Zhogla, I. V. Halets-Bui, S. Zh Loznikova, M. Bryshewska, M. Ionov, I. Waczulikova, J. P. Majoral e D. G. Shcharbin. "Interaction of polyamidoamine dendrimers and amphiphylic dendrons with lipid membranes". Proceedings of the National Academy of Sciences of Belarus, Biological Series 66, n.º 4 (10 de novembro de 2021): 497–512. http://dx.doi.org/10.29235/1029-8940-2021-66-4-497-512.

Texto completo da fonte

Resumo:

Polyamidoamine (PAMAM) dendrimers and amphiphilic dendrons are one of the types of nanomaterials characterized by a hyperbranched structure of polymer branches. In the case of dendrimers, the dendrons are covalently linked at the central focal point. In the case of amphiphilic dendrons, dendrons are non-covalently linked by hydrophobic interactions, forming micellar structures. These nanoparticles are widely used in biology and medicine as contrast agents, carriers of drugs and genetic material. Their use in scientific practice requires an understanding of the basic mechanisms of their interaction with membranes – the main obstacle to the entry of dendrimers into the cell. This review discusses the regularities of the interaction of dendrimers and amphiphilic dendrons with lipid membranes. Various models of dendrimer-membrane interactions are described as the basis for the penetration of dendrimers and amphiphilic nanoparticles into cells. Keywords: polyamidoamine dendrimers, amphiphilic dendrons, lipid membranes, cells, antitumor therapeutics, antibacterial agents, diagnostics, genetic therapy.

Estilos ABNT, Harvard, Vancouver, APA, etc.

29

Beketov, Alexander A., Ivan V. Mikhailov e Anatoly A. Darinskii. "Stability of DMPC Liposomes Externally Conjugated with Branched Polyglycerol". International Journal of Molecular Sciences 23, n.º 16 (15 de agosto de 2022): 9142. http://dx.doi.org/10.3390/ijms23169142.

Texto completo da fonte

Resumo:

Vesicles formed by DMPC liposomes externally conjugated with branched polyglycerol-dendrons as well as linear PEG in water solution were simulated using the DPD method. Such a structure of vesicles corresponds to the structure of polymer-grafted liposomes obtained experimentally by the post-insertion method, in which polymer chains are fixed on the outer surface of the liposome. The grafting density, generation number and spacer length of grafted dendrons were varied. It was shown that modification of the outer surface of liposomes due to grafting of hydrophilic dendrons has practically no effect on the size and shape of the vesicle, as well as on the morphology of the lipid membrane up to certain critical thresholds of grafting density, degree of polymerization, and generation number of grafted molecules. Exceeding the threshold values of these structural parameters leads to irreversible deformation of the lipid membrane. Diffusion through the membrane and the transition of grafted molecules from the outer surface of the liposome to the inner surface is not observed for dendrons with a generation number higher than one, even at high grafting densities. The critical values of the generation number and the characteristics of the molecular coating at these values were determined for various grafting densities and spacer lengths of the grafted chains. It was shown that the chemical potential of the grafted dendron can serve as a stability metric for the conjugated liposome. The chemical potential of grafted molecules was calculated using the mean field model of the spherical brush on the liposome surface. An analysis of the simulation data shows that, within the framework of the applicability of the mean field approach, the value of the chemical potential is a sufficient criterion for separating vesicles into stable and unstable forms. These results can be used as a guide for the experimental design of nanocontainers based on lipid vesicles with an external protective coating of branched macromolecules.

Estilos ABNT, Harvard, Vancouver, APA, etc.

30

Gabriel, Christopher J., e Jon R. Parquette. "Expanding Dendrons. The Photoisomerism of Folded Azobenzene Dendrons". Journal of the American Chemical Society 128, n.º 42 (outubro de 2006): 13708–9. http://dx.doi.org/10.1021/ja066126z.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

31

Dong, Zhengqi, Hanhong Qiu, Meihua Han, Rui Wang, Yifei Guo e Xiangtao Wang. "Honokiol-Based Nanomedicine Decorated with Ethylene Glycols Derivatives Promotes Antitumor Efficacy". Journal of Biomedical Nanotechnology 17, n.º 8 (1 de agosto de 2021): 1564–73. http://dx.doi.org/10.1166/jbn.2021.3126.

Texto completo da fonte

Resumo:

Honokiol-loaded nanoparticles (HK-loaded NPs) exhibit potential antitumor activity; however, the factors affecting their antitumor efficacy are still unclear and need to be explored. This research was aimed to systematically estimate the influence of feed weight ratio (FWR) and nanocarrier structure on antitumor activity. Accordingly, three types of ethylene glycol derivatives, including linear poly(ethylene glycol) with molar mass of 2000 (PEG45), first and second generation oligo(ethylene glycol) dendrons (G1 and G2) were used as nanocarriers, and a series of HK-loaded NPs with different FWR were prepared successfully using the evaporation-ultrasonication method. These NPs showed similar stability but demonstrated differences with respect to particle size, morphology, cumulative profile, and antitumor efficacy. The influence of the FWR was studied using G1 dendrons as nanocarriers; the results indicated that the particle size and morphology of G1 NPs were significantly affected, and G1 NPs (8/1), with the FWR of 8/1 for HK versus G1 dendron, exhibited the highest antitumor activity among all G1 NPs. Furthermore, the influence of nanocarrier structure was investigated at the FWR of 4/1; the findings revealed reduction in the particle diameter from 280 nm to 109 nm and change in morphology from sphere to flower-like structure with an increase in the branch degree from linear to dendron. Moreover, G2 NPs (4/1), with the FWR of 4/1 for HK versus G2 dendron, carrying the highest branch degree exhibited the greatest antitumor efficacy among all. These results are suggestive of influence of particle size and morphology on antitumor efficacy of HK-loaded NPs. Conclusively, this study demonstrated nanocarrier structure and the FWR significantly affect the antitumor efficacy of NPs, which should be optimized for designing nanoscale delivery systems.

Estilos ABNT, Harvard, Vancouver, APA, etc.

32

Xu, Li, Lidong Shao, Minqi Hu, Lin Chen e Yunmei Bi. "A thermoresponsive amphiphilic dendron — Synthesis, characterization, and self-assembled micelles for controlled drug release". Canadian Journal of Chemistry 90, n.º 7 (julho de 2012): 600–607. http://dx.doi.org/10.1139/v2012-038.

Texto completo da fonte

Resumo:

A new third-generation thermoresponsive amphiphilic dendron consisting of a hydrophobic poly(benzyl ether) dendritic core and hydrophilic oligo(ethylene glycol) peripheries was synthesized by an efficient convergent approach. Its structure was confirmed by 1H NMR, 13C NMR, IR, GPC, MALDI-TOF MS, and elemental analysis. Turbidity and dynamic light scattering (DLS) measurements demonstrated that the dendron showed a reversible temperature-dependent phase-transition behavior in aqueous solution and its lower critical solution temperature (LCST) was lower than that of the corresponding second-generation dendron, indicating the dependence of LCSTs on the generation of dendrons. Fluorescent spectroscopy and TEM studies revealed that the dendron would self-assemble into nanospherical micelles with a very low critical micelle concentration (CMC) in water. The core-shell structure of the micelles was proved by 1H NMR analyses of the micelles in D2O. The drug-loading capacity of the dendron micelles is about 29 wt % for podophyllotoxin (POD) used as a model drug, and in vitro release tests showed a desired thermoresponsive drug-release behavior. These results indicate that the dendron is promising as stimuli-responsive material for biomedical applications.

Estilos ABNT, Harvard, Vancouver, APA, etc.

33

Zare, Alireza, Borja Pascual-Jose, Silvia De la Flor, Amparo Ribes-Greus, Xavier Montané, José Antonio Reina e Marta Giamberini. "Membranes for Cation Transport Based on Dendronized Poly(epichlorohydrin-co-ethylene oxide). Part 1: The Effect of Dendron Amount and Column Orientation on Copolymer Mobility". Polymers 13, n.º 20 (14 de outubro de 2021): 3532. http://dx.doi.org/10.3390/polym13203532.

Texto completo da fonte

Resumo:

Dendronized polyethers give rise to columnar LC structures which can successfully act as cation transport materials. Therefore, we prepared two different materials, based on Poly(epichlorohydrin-co-ethylene oxide) (PECH-co-EO) grafted with methyl 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, containing 20% or 40% modified units, respectively. The obtained polymers were characterized by differential scanning calorimetry (DSC), X-ray diffraction and optical microscopy between crossed polars (POM) and compared to the unmodified PECH-co-EO. In order to reach efficient transport properties, homeotropically oriented membranes were prepared by a fine-tuned thermal annealing treatment and were subsequently investigated by dynamic mechanical thermal analysis (DMTA) and dielectric thermal analysis (DETA). We found that the presence of the dendrons induces a main chain partial crystallization of the polyether chain and coherently increases the polymer Tg. This effect is more evident in the oriented membranes. As for copolymer orientation upon annealing, the cooling rate and the annealing temperature were the most crucial factors. DMTA and DETA confirmed that grafting with the dendron strongly hinders copolymer motions, but did not show great differences between unoriented and oriented membranes, regardless of the amount of dendrons.

Estilos ABNT, Harvard, Vancouver, APA, etc.

34

Fatykhova, А. M., V. A. Burilov, S. E. Solovieva e I. S. Antipin. "SYNTHESIS OF A POLYFUNCTIONAL DENDRON BASED ON GALLIC ACID USING THE AZIDE-ALKYNE CYCLOADDITION REACTION". Доклады Российской академии наук. Химия, науки о материалах 513, n.º 1 (1 de novembro de 2023): 11–17. http://dx.doi.org/10.31857/s2686953522600830.

Texto completo da fonte

Resumo:

By stepwise modification of gallic acid using an azide-alkyne cycloaddition reaction, a first-generation triazole-containing dendron with hydroxypropyltriazole groups and a tetraethylene glycol linker was obtained for the first time. The structure of all intermediate compounds has been proven by modern physical methods. It has been established that the use of bromomethylene derivatives of gallic acid in the synthesis of triazole-containing dendrons results in the formation of by-products of alkylation of the bases used in the reaction (triethylamine and diisopropylethylamine) due to the high mobility of the bromine atom in the benzyl position.

Estilos ABNT, Harvard, Vancouver, APA, etc.

35

Guo, Wei, Yongjie Wang, Pengqi Wan, Hao Wang, Li Chen, Shaokun Zhang, Chunsheng Xiao e Xuesi Chen. "Cationic amphiphilic dendrons with effective antibacterial performance". Journal of Materials Chemistry B 10, n.º 3 (2022): 456–67. http://dx.doi.org/10.1039/d1tb02037d.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

36

Perli, Gabriel, Diego L. Bertuzzi, Dênio E. P. Souto, Miguel D. Ramos, Carolyne B. Braga, Samile B. Aguiar e Catia Ornelas. "Synthesis and Characterization of Dendronized Gold Nanoparticles Bearing Charged Peripheral Groups with Antimicrobial Potential". Nanomaterials 12, n.º 15 (29 de julho de 2022): 2610. http://dx.doi.org/10.3390/nano12152610.

Texto completo da fonte

Resumo:

Dendronized gold nanoparticles (AuNPs) were synthesized bearing charged peripheral groups. Two novel AB3-type dendrons were synthesized with a thiol group at the focal point followed by their attachment to AuNPs. Dendrons were designed to have nine charged peripheral groups (carboxyl or amine), glycol solubilizing, units and one thiol moiety at the focal point. Both dendrons and all intermediates were synthesized in high yields and characterized by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). The amine- and carboxyl-terminated dendrons were used to functionalize gold nanoparticles (AuNPs) previously stabilized with citrate. The nanoparticles’ diameters and their colloidal stability were investigated using dynamic light scattering (DLS). The size and morphology of the dendronized AuNPs were evaluated by scanning electron microscopy (SEM), which revealed individual particles with no aggregation after replacement of citrate by the dendrons, in agreement with the DLS data. The absorption spectroscopy reveals a prominent plasmonic band at 560 nm for all AuNPs. The zeta potential further confirmed the expected charged structures of the dendronized AuNPs. Considering all the physical–chemical properties of the charged dendronized AuNPs developed in this work, these AuNPs might be used as a weapon against multi-drug resistant bacterial infections.

Estilos ABNT, Harvard, Vancouver, APA, etc.

37

Ryzhkov, Aleksei I., Fedor V. Drozdov, Georgij V. Cherkaev e Aziz M. Muzafarov. "Approaches to the Functionalization of Organosilicon Dendrones Based on Limonene". Applied Sciences 13, n.º 4 (7 de fevereiro de 2023): 2121. http://dx.doi.org/10.3390/app13042121.

Texto completo da fonte

Resumo:

Previously, we reported the synthesis of carbosilane and carbosilane-siloxane dendrons of various generations based limonene, a natural terpene. Limonene that contains two double bonds, namely cyclohexene and isoprenyl ones, was shown to undergo regioselective hydrosilylation exclusively at its isoprenyl double bond. This finding was used to prepare carbosilane dendrons (CDs) with a limonene moiety at the focal point. In this study, we present variants for the functionalization of the cyclohexene double bond by an epoxidation reaction in order to use the resulting dendrons for the preparation of various macromolecular objects, including Janus dendrimers (JDs), dendronized polymers, and macroinitiators. Moreover, it was shown that dendrons with peripheral azide functions could be obtained. These methods offer both the possibilities of the further growth of branches and the addition of polymers with a different nature by the azide–alkyne cycloaddition reaction.

Estilos ABNT, Harvard, Vancouver, APA, etc.

38

Mezzenga, Raffaele, e Dieter A. Schlüter. "Dendrons, Dendrimers…. Octopus!" CHIMIA International Journal for Chemistry 63, n.º 4 (29 de abril de 2009): 230. http://dx.doi.org/10.2533/chimia.2009.230.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

39

Kölmel, Dominik K., Martin Nieger e Stefan Bräse. "Highly efficient synthesis of polyfluorinated dendrons suitable for click chemistry". RSC Advances 5, n.º 46 (2015): 36762–65. http://dx.doi.org/10.1039/c5ra02804c.

Texto completo da fonte

Resumo:

A new and efficient access to C_2v-symmetric dendrons with up to 72 magnetically equivalent fluorine atoms is presented. Those dendrons are well suited to act as potential ¹⁹F MRI probes.

Estilos ABNT, Harvard, Vancouver, APA, etc.

40

Park, Minwook, Dong-Gue Kang, Won-Jin Yoon, Yu-Jin Choi, Jahyeon Koo, Seok-In Lim e Kwang-Un Jeong. "Programmed Hierarchical Hybrid Nanostructures from Fullerene-Dendrons and Pyrene-Dendrons". Small 14, n.º 49 (10 de outubro de 2018): 1803291. http://dx.doi.org/10.1002/smll.201803291.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

41

Abad, Miriam, Alejandro Martínez-Bueno, Gracia Mendoza, Manuel Arruebo, Luis Oriol, Víctor Sebastián e Milagros Piñol. "Supramolecular Functionalizable Linear–Dendritic Block Copolymers for the Preparation of Nanocarriers by Microfluidics". Polymers 13, n.º 5 (25 de fevereiro de 2021): 684. http://dx.doi.org/10.3390/polym13050684.

Texto completo da fonte

Resumo:

Hybrid linear–dendritic block copolymers (LDBCs) having dendrons with a precise number of peripheral groups that are able to supramolecular bind functional moieties are challenging materials as versatile polymeric platforms for the preparation of functional polymeric nanocarriers. PEG2k-b-dxDAP LDBCs that are based on polyethylene glycol (PEG) as hydrophilic blocks and dendrons derived from bis-MPA having 2,6-diacylaminopyridine (DAP) units have been efficiently synthesized by the click coupling of preformed blocks, as was demonstrated by spectroscopic techniques and mass spectrometry. Self-assembly ability was first checked by nanoprecipitation. A reproducible and fast synthesis of aggregates was accomplished by microfluidics optimizing the total flow rate and phase ratio to achieve spherical micelles and/or vesicles depending on dendron generation and experimental parameters. The morphology and size of the self-assemblies were studied by TEM, Cryogenic Transmission Electron Microscopy (cryo-TEM), and Dynamic Light Scattering (DLS). The cytotoxicity of aggregates synthesized by microfluidics and the influence on apoptosis and cell cycle evaluation was studied on four cell lines. The self-assemblies are not cytotoxic at doses below 0.4 mg mL−1. Supramolecular functionalization using thymine derivatives was explored for reversibly cross-linking the hydrophobic blocks. The results open new possibilities for their use as drug nanocarriers with a dynamic cross-linking to improve nanocarrier stability but without hindering disassembly to release molecular cargoes.

Estilos ABNT, Harvard, Vancouver, APA, etc.

42

Teruel-Juanes, R., B. Pascual-Jose, R. Graf, J. Reina, M. Giamberini e A. Ribes-Greus. "Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers". Polymers 13, n.º 12 (13 de junho de 2021): 1961. http://dx.doi.org/10.3390/polym13121961.

Texto completo da fonte

Resumo:

The macromolecular dynamics of dendronized copolymer membranes (PECHs), obtained by chemical modification of poly(epichlorohydrin) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, was investigated. In response to a thermal treatment during membrane preparation, these copolymers show an ability to change their shape, achieve orientation, and slightly crystallize, which was also observed by CP-MAS NMR, XRD, and DSC. The phenomenon was deeply analyzed by dielectric thermal analysis. The dielectric spectra show the influence of several factors such as the number of dendritic side groups, the orientation, their self-assembling dendrons, and the molecular mobility. The dielectric spectra present a sub-Tg dielectric relaxation, labelled as γ, associated with the mobility of the benzyloxy substituent of the dendritic group. This mobility is not related to the percentage of these lateral chains but is somewhat hindered by the orientation of the dendritic groups. Unlike other less complex polymers, the crystallization was dismantled before the appearance of the glass transition (αTg). Only after that, clearing transition (αClear) can be observed. The PECHs were flexible and offered a high free volume, despite presenting a high degree of modifications. However, the molecular mobility is not independent in each phase and the self-assembling dendrons can be eventually fine-tuned according to the percentage of grafted groups.

Estilos ABNT, Harvard, Vancouver, APA, etc.

43

Poudel, Dhruba P., e Richard T. Taylor. "Synthesis of Fluorescent, Dumbbell-Shaped Polyurethane Homo- and Heterodendrimers and Their Photophysical Properties". International Journal of Molecular Sciences 24, n.º 2 (14 de janeiro de 2023): 1662. http://dx.doi.org/10.3390/ijms24021662.

Texto completo da fonte

Resumo:

Fluorescent dendrimers have wide applications in biomedical and materials science. Here, we report the synthesis of fluorescent polyurethane homodendrimers and Janus dendrimers, which often pose challenges due to the inherent reactivity of isocyanates. Polyurethane dendrons (G1–G3) were synthesized via a convergent method using a one-pot multicomponent Curtius reaction as a crucial step to establish urethane linkages. The alkyne periphery of the G1–G3 dendrons was modified by a copper catalyzed azide–alkyne click reaction (CuAAC) to form fluorescent dendrons. In the reaction of the surfaces functionalized two different dendrons with a difunctional core, a mixture of three dendrimers consisting of two homodendrimers and a Janus dendrimer were obtained. The Janus dendrimer accounted for a higher proportion in the products’ distribution, being as high as 93% for G3. The photophysical properties of Janus dendrimers showed the fluorescence resonance energy transfer (FRET) from one to the other fluorophore of the dendrimer. The FRET observation accompanied by a large Stokes shift make these dendrimers potential candidates for the detection and tracking of interactions between the biomolecules, as well as potential candidates for fluorescence imaging.

Estilos ABNT, Harvard, Vancouver, APA, etc.

44

Nishida, Masakazu, Hiroaki Horiuchi, Atsuya Momotake, Yoshinobu Nishimura, Hiroshi Hiratsuka e Tatsuo Arai. "Singlet molecular oxygen generation by water-soluble phthalocyanine dendrimers with different aggregation behavior". Journal of Porphyrins and Phthalocyanines 15, n.º 01 (janeiro de 2011): 47–53. http://dx.doi.org/10.1142/s1088424611003008.

Texto completo da fonte

Resumo:

Phthalocyanines having hydrophilic or lipophilic dendrons were synthesized to investigate the efficiencies of singlet molecular oxygen (1Δg) formation. The introduction of higher generation of dendrons to the central metal ( Si ) of phthalocyanine in vertical direction to their ring plane has resulted in the successful improvement in avoiding aggregate formation that resulted in efficient generation of 1Δg even in water.

Estilos ABNT, Harvard, Vancouver, APA, etc.

45

Apartsin, Evgeny K., Nadezhda Knauer, Ulf Dietrich Kahlert e Anne-Marie Caminade. "Amphiphilic Triazine-Phosphorus Metallodendrons Possessing Anti-Cancer Stem Cell Activity". Pharmaceutics 14, n.º 2 (10 de fevereiro de 2022): 393. http://dx.doi.org/10.3390/pharmaceutics14020393.

Texto completo da fonte

Resumo:

Dendritic molecules bearing metal complexes in their structure (metallodendrimers and metallodendrons) are considered prospective therapeutic entities. In particular, metallodendrons raise interest as antitumor agents for the treatment of poorly curable or drug-resistant tumors. Herein, we have synthesized amphiphilic triazine-phosphorus dendrons bearing multiple copper (II) or gold (III) complexes on the periphery and a branched hydrophobic fragment at the focal point. Due to their amphiphilic nature, metallodendrons formed single micelles (mean diameter ~9 nm) or multi-micellar aggregates (mean diameter ~60 nm) in a water solution. We have tested the antitumor activity of amphiphilic metallodendrons towards glioblastoma, a malignant brain tumor with a notoriously high level of therapy resistance, as a model disease. The metallodendrons exhibit higher cytotoxic activity towards glioblastoma stem cells (BTSC233, JHH520, NCH644, and SF188 cell lines) and U87 glioblastoma cells (IC50 was 3–6 µM for copper-containing dendron and 11–15 µM for gold-containing dendron) in comparison with temozolomide (IC50 >100 µM)—the clinical standard of care for glioblastoma. Our findings show the potential of metallodendron-based nanoformulations as antitumor entities.

Estilos ABNT, Harvard, Vancouver, APA, etc.

46

Sarigul, Ender, Merve Zaim, Mehmet Senel, Tugba Sagir e Sevim Isik. "Polyamidoamine Dendron-Bearing Lipids as Drug-Delivery Excipients". Molecules 27, n.º 22 (13 de novembro de 2022): 7817. http://dx.doi.org/10.3390/molecules27227817.

Texto completo da fonte

Resumo:

An amine-terminated polyamidoamine (PAMAM) dendron and two long alkyl groups were designed as a novel drug carrier that possesses an interior for the encapsulation of drugs and a biocompatible surface. We synthesized three dendron-bearing lipids, DL-G1, DL-G2, and DL-G3, which included first, second, and third generation polyamidoamine dendrons, respectively. The synthesized dendrimer encapsulating anticancer drug, 5-fluorouracil (5-FU), was prepared by extraction with chloroform from mixtures of the dendrimers and varying amounts of the drug. In vitro cytotoxicity of PAMAM conjugated di-n-dodecylamine micelles (G1, G2, G3) were analyzed on human gastric adenocarcinoma cells (AGS) by water-soluble tetrazolium-1 (WST-1) cell proliferation assay. Upon exposure to 5-FU loaded micelles, the viability of the cells decreased gradually in all generations. Cytotoxicity increased with increasing generation and reached its highest rate of 69.8 ± 3.2% upon 15 µM 5FU-loaded 25 µM PAMAM DL-3 micelle treatment. These results demonstrate that 5FU-loaded PAMAM conjugated di-n-dodecylamine treatment inhibits the proliferation of AGS cells in a generation-dependent manner.

Estilos ABNT, Harvard, Vancouver, APA, etc.

47

Shavykin, Oleg V., Sofia E. Mikhtaniuk, Emil I. Fatullaev, Igor M. Neelov, Frans A. M. Leermakers, Mariano E. Brito, Christian Holm, Oleg V. Borisov e Anatoly A. Darinskii. "Hybrid Molecules Consisting of Lysine Dendrons with Several Hydrophobic Tails: A SCF Study of Self-Assembling". International Journal of Molecular Sciences 24, n.º 3 (20 de janeiro de 2023): 2078. http://dx.doi.org/10.3390/ijms24032078.

Texto completo da fonte

Resumo:

In this article, we used the numerical self-consistent field method of Scheutjens–Fleer to study the micellization of hybrid molecules consisting of one polylysine dendron with charged end groups and several linear hydrophobic tails attached to its root. The main attention was paid to spherical micelles and the determination of the range of parameters at which they can appear. A relationship has been established between the size and internal structure of the resulting spherical micelles and the length and number of hydrophobic tails, as well as the number of dendron generations. It is shown that the splitting of the same number of hydrophobic monomers from one long tail into several short tails leads to a decrease in the aggregation number and, accordingly, the number of terminal charges in micelles. At the same time, it was shown that the surface area per dendron does not depend on the number of hydrophobic monomers or tails in the hybrid molecule. The relationship between the structure of hybrid molecules and the electrostatic properties of the resulting micelles has also been studied. It is found that the charge distribution in the corona depends on the number of dendron generations G in the hybrid molecule. For a small number of generations (up to G=3), a standard double electric layer is observed. For a larger number of generations (G=4), the charges of dendrons in the corona are divided into two populations: in the first population, the charges are in the spherical layer near the boundary between the micelle core and shell, and in the second population, the charges are near the periphery of the spherical shell. As a result, a part of the counterions is localized in the wide region between them. These results are of potential interest for the use of spherical dendromicelles as nanocontainers for drug delivery.

Estilos ABNT, Harvard, Vancouver, APA, etc.

48

Malyutin, A. V. "Groups Acting on Dendrons". Journal of Mathematical Sciences 212, n.º 5 (8 de janeiro de 2016): 558–65. http://dx.doi.org/10.1007/s10958-016-2688-2.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

49

Kose, Meliha Merve, Sebla Onbulak, Idil Ipek Yilmaz e Amitav Sanyal. "Orthogonally “Clickable” Biodegradable Dendrons". Macromolecules 44, n.º 8 (26 de abril de 2011): 2707–14. http://dx.doi.org/10.1021/ma200593r.

Texto completo da fonte

Estilos ABNT, Harvard, Vancouver, APA, etc.

50

Shi, Da, Justine Wallyn, Dinh-Vu Nguyen, Francis Perton, Delphine Felder-Flesch, Sylvie Bégin-Colin, Mounir Maaloum e Marie Pierre Krafft. "Microbubbles decorated with dendronized magnetic nanoparticles for biomedical imaging: effective stabilization via fluorous interactions". Beilstein Journal of Nanotechnology 10 (31 de outubro de 2019): 2103–15. http://dx.doi.org/10.3762/bjnano.10.205.

Texto completo da fonte

Resumo:

Dendrons fitted with three oligo(ethylene glycol) (OEG) chains, one of which contains a fluorinated or hydrogenated end group and bears a bisphosphonate polar head (C n X2 n +1OEG8Den, X = F or H; n = 2 or 4), were synthesized and grafted on the surface of iron oxide nanoparticles (IONPs) for microbubble-mediated imaging and therapeutic purposes. The size and stability of the dendronized IONPs (IONP@C n X2 n +1OEG8Den) in aqueous dispersions were monitored by dynamic light scattering. The investigation of the spontaneous adsorption of IONP@C n X2 n +1OEG8Den at the interface between air or air saturated with perfluorohexane and an aqueous phase establishes that exposure to the fluorocarbon gas markedly increases the rate of adsorption of the dendronized IONPs to the gas/water interface and decreases the equilibrium interfacial tension. This suggests that fluorous interactions are at play between the supernatant fluorocarbon gas and the fluorinated end groups of the dendrons. Furthermore, small perfluorohexane-stabilized microbubbles (MBs) with a dipalmitoylphosphatidylcholine (DPPC) shell that incorporates IONP@C n X2 n +1OEG8Den (DPPC/Fe molar ratio 28:1) were prepared and subsequently characterized using both optical microscopy and an acoustical method of size determination. The dendrons fitted with fluorinated end groups lead to smaller and more stable MBs than those fitted with hydrogenated groups. The most effective result is already obtained with C2F5, for which MBs of ≈1.0 μm in radius reach a half-life of ≈6.0 h. An atomic force microscopy investigation of spin-coated mixed films of DPPC/IONP@C2X5OEG8Den combinations (molar ratio 28:1) shows that the IONPs grafted with the fluorinated dendrons are located within the phospholipid film, while those grafted with the hydrocarbon dendrons are located at the surface of the phospholipid film.

Estilos ABNT, Harvard, Vancouver, APA, etc.

Artigos de revistas sobre o tema "Dendrons"

Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos