Journal articles: 'GENERATION DENDRIMERS'

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Milenin, Sergey A., Elizaveta V. Selezneva, Pavel A. Tikhonov, Viktor G. Vasil’ev, Alexander I. Buzin, Nikolay K. Balabaev, Andrey O. Kurbatov, et al. "Hybrid Polycarbosilane-Siloxane Dendrimers: Synthesis and Properties." Polymers 13, no. 4 (February 17, 2021): 606. http://dx.doi.org/10.3390/polym13040606.

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A series of carbosilane dendrimers of the 4th, 6th, and 7th generations with a terminal trimethylsilylsiloxane layer was synthesized. Theoretical models of these dendrimers were developed, and equilibrium dendrimer conformations obtained via molecular dynamics simulations were in a good agreement with experimental small-angle X-ray scattering (SAXS) data demonstrating molecule monodispersity and an almost spherical shape. It was confirmed that the glass transition temperature is independent of the dendrimer generation, but is greatly affected by the chemical nature of the dendrimer terminal groups. A sharp increase in the zero-shear viscosity of dendrimer melts was found between the 5th and the 7th dendrimer generations, which was qualitatively identical to that previously reported for polycarbosilane dendrimers with butyl terminal groups. The viscoelastic properties of high-generation dendrimers seem to follow some general trends with an increase in the generation number, which are determined by the regular branching structure of dendrimers.

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Gajjar, Dhaval G., Rinkesh M. Patel, Hema N. Patel, and Pravinkumar M. Patel. "Designing, characterization, and thermal behavior of triazine-based dendrimers." Journal of Polymer Engineering 35, no. 1 (January 1, 2015): 41–52. http://dx.doi.org/10.1515/polyeng-2014-0123.

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Abstract Different generations of dendritic architecture with piperazine in core moiety and hydroxyl groups on the periphery were designed by divergent method. 1,4-biz(4,6-trichloro-1,3,5-triazin-2-yl)piperazine was synthesized as a core for dendrimer synthesis. Dendrimer was then grown to G3 from core compound using diethanolamine and cyanuric chloride as branching units. Dendrimer generations were characterized by infrared (IR) spectroscopy [Fourier transform IR (FTIR)], 1H-nuclear magnetic resonance (NMR), 13C-NMR, electrospray ionization-mass spectrometry (ESI-MS), and elemental analysis. The thermal behavior of both full- and half-generation dendrimers was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA study revealed that dendrimer generations had a moderate thermal stability. Chlorine-terminated half-generation dendrimers were thermally more stable than hydroxyl-terminated full-generation dendrimers. The DSC technique was employed to determine the glass transition temperatures (Tg) of dendrimer generations. It was observed that the glass transition temperatures of synthesized dendrimer generations were of low value, which is similar to the values reported for the polyamidoamine (PAMAM) dendrimer of the same generation. It was also observed that, with the increase in the molecular weight or generation number of dendrimer, the glass transition temperature was also increased.

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Rajakumar, Perumal, and Devaraj Anandkumar. "Photophysical and Electrochemical Properties and Anticancer Activities of Porphyrin-Cored Fluorenodendrimers Synthesized by Click Chemistry." Synlett 29, no. 15 (August 14, 2018): 1995–2000. http://dx.doi.org/10.1055/s-0037-1610218.

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A new class of porphyrin-cored fluorenodendrimers were synthesized by a convergent approach through click chemistry. The zeroth-, first-, and second-generation porphyrin-cored fluorenodendrimers were characterized by means of 1H and 13C NMR spectroscopy, UV-vis spectroscopy, fluorescent spectroscopy, elemental analysis, and MALDI-TOF mass spectrometry. The UV-vis spectrum of the dendrimers showed an increase in the absorption intensity on increasing the dendrimer generation, and a bathochromic shift was observed for higher-generation dendrimers compared with lower-generation dendrimers. The dendrimers showed emission bands at 317, 604–668, and 617–668 nm, the intensity of which increased with increasing dendrimer generation. All the synthesized dendrimers exhibited a reversible oxidation potential in cyclic voltammetry. The therapeutic efficacy of the porphyrin-cored fluorenodendrimers for the inhibition of a growth tumor cell (PA-1) increased with increasing generation number of the dendrimer.

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Rajakumar, Perumal, Nagarathinam Venkatesan, Karuppannan Sekar, Subramani Nagaraj, and Ramasamy Rengasamy. "Synthesis, Optical, and Antioxidant Studies of Anthraquinone-core-based Dendrimers with N-Phenylcarbazole as Surface Group." Australian Journal of Chemistry 67, no. 4 (2014): 636. http://dx.doi.org/10.1071/ch13521.

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Synthesis of hyperbranched dendrimers up to third generation with N-phenylcarbazole as surface group and anthraquinone as the core unit has been achieved. The fluorescence decay studies of the dendrimers indicate that generation growth alters the relaxation time. The highly branched third-generation dendrimer has a longer relaxation time than the zero-, first-, and second-generation dendrimers. Similarly, higher-generation dendrimers show better antioxidant behaviour with 1,1-diphenyl-2-picryl hydrazyl than the lower-generation dendrimers.

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Sathiya Savithri, Jothinathan, and Perumal Rajakumar. "Synthesis, photophysical, antibacterial and molecular docking studies on aromatic ring core-containing rhodamine B decorated triazole bridged dendrimers." New Journal of Chemistry 42, no. 24 (2018): 19390–99. http://dx.doi.org/10.1039/c8nj02943a.

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Rhodamine B decorated dendrimers 1–6 were synthesized by a convergent approach using click chemistry. The zeroth generation dendrimer 1 (G0) and the first generation dendrimer 4 (G1) showed better antibacterial activity than the other dendrimers.

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Dwivedi, Nitin, Balak Das Kurmi, Prashant Kesharwani, and Jigna Shah. "GENERATION DEPENDENT TARGETING POTENTIAL OF DONEPEZIL LOADED POLY (PROPYLENEIMINE) DENDRIMER THROUGH GOAT NASAL MUCOSA." International Journal of Pharmacy and Pharmaceutical Sciences 10, no. 12 (December 1, 2018): 80. http://dx.doi.org/10.22159/ijpps.2018v10i12.29912.

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Objective: In the domain of nano drug delivery, dendrimers are the most explored bioactive polymeric carrier system. The present work was aimed to study the diffusion potential of different generations of Poly (propyleneimine) (PPI) dendrimers on goat nasal mucosa in an ex vivo study and synthesize a stable dendrimer for olfactory drug delivery.Methods: The generations (3.0G, 4.0G, and 5.0G) of PPI dendrimer were synthesized, and PEGylated by MPEG 5000 and then loaded with donepezil. A comparative study was carried out among all generations in term of their drug loading capacity, stability, sustained release behaviour as well as for targeting efficacy. An ex-vivo study was carried out on Franz Diffusion Cell with goat nasal mucosa.Results: The developed G3, G4, and G5 dendrimerformulations had entrapment efficiency of 24.33±0.56%, 40.12±0.62%, and 60.4±0.6%, respectively. The nasal diffusion study revealed that 5.0G PPI dendrimer increased diffusion of donepezil up to 47% as compared to the pure solution of donepezil while 10% improvement in diffusion was seen as compared to 4.0 G PPI dendrimer. Thus obtained results claimed that the drug loading as well as targeting potential of PPI dendrimers increased with the increase in the number of generation. The investigation outcome indicated promising results of 5.0G PPI dendrimer over the 3.0G and 4.0G PPI dendrimer generations for their drug loading capacity, stability, and sustained release action.Conclusion: The 5.0G PPI dendrimer proved its superior candidature over the other lower generations of PPI dendrimers for drug delivery and drug targeting.

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Salamończyk, Grzegorz M. "A Fast and Convenient Synthesis of New Water-Soluble, Polyanionic Dendrimers." Molecules 26, no. 16 (August 6, 2021): 4754. http://dx.doi.org/10.3390/molecules26164754.

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Reasonably simple, efficient, and possessing aspects of generality, the methodology for the synthesis of new, water-soluble, dendrimeric polyesters with great potential applications as antiviral drugs in their own right is described. The essential aspect of the presented approach is a quite unique, immediate access to the polyanionic material at each generation during divergent synthesis. Six target polyanionic dendrimers (generations 1, 2, and 3) have been synthesized. The key monomers applied in this project were 1,3,5-benzenetricarboxylic acid derivatives, which also worked as direct precursors of the charged dendrimer surface.

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Ashrafi, Frydon, Tahereh Mahbobi, and Ashraf Sadat Ghasemi. "Computational study adsorption of mercaptopurine in generation G3 and G5 PAMAM dendrimers." Ciência e Natura 37 (December 21, 2015): 12. http://dx.doi.org/10.5902/2179460x20822.

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Due to its unique properties of dendrimers as well as with high-level groups, a special ability to carry drugs. In this study compared the interaction between the two generations of poly (amidoamine) PAMAM (G3and G5) dendrimers and the drug 6-mercaptopurine (6-MP) and the drug entrapment within the structure of dendrimers the electrostatic and covalent complexation of drugs to the dendrimer surface have been studied. The use of drug-dendrimer complex enhanced drug solubility and bioavailability of the drug.

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Ficker, Mario, Valentina Paolucci, and Jørn B. Christensen. "Improved large-scale synthesis and characterization of small and medium generation PAMAM dendrimers." Canadian Journal of Chemistry 95, no. 9 (September 2017): 954–64. http://dx.doi.org/10.1139/cjc-2017-0108.

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Dendrimers are promising polymers for biomedical applications; however, most dendrimer formulations have failed to move from laboratory science to upscaled products for preclinical testing or GMP production. This publications reports on an improved large-scale PAMAM dendrimer synthesis that is suitable to manufacture large amounts of highly pure and monodisperse dendrimers of generations G0–G5. Furthermore, an extended analytical guideline how to characterize PAMAM dendrimers with NMR, HPLC, SEC-MALS, ESI, MALDI, UV–vis, fluorescence, and IR spectroscopy is provided.

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Sabirov, Denis, Alina Tukhbatullina, and Igor Shepelevich. "Information Entropy of Regular Dendrimer Aggregates and Irregular Intermediate Structures." Liquids 1, no. 1 (March 5, 2021): 25–35. http://dx.doi.org/10.3390/liquids1010002.

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Dendrimer molecules and aggregates are chemical structures with regular branching that underlies their physicochemical properties. Regular dendrimers have been studied both theoretically and experimentally, but the irregular intermediate structures between the dendrimers of neighboring generations have not. In the present work, dendrimer aggregates, both regular and intermediate, are investigated in terms of the information entropy approach. As found, the information entropy of the regular dendrimer asymptotically increases with the generation number; herewith, its maximal value equals 2. The intermediate structures have been studied for the growing dendrimer G1 → G2 → G3 → G4 with the tricoordinated building block. The plot of the information entropy of the growing dendrimer on the size has the frontier consisting of the lowest values that correspond to the regular and irregular structures described with the symmetrical graphs. Other intermediate structures have information entropies higher than the regular dendrimers. Thus, to move the system from one informationally stable state to another, its information capacity must be temporarily increased.

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Chirag M, Gowda D V, Sathish Babu, and Famna Roohi N K. "A Comprehensive review on Dendrimers in current advanced Drug delivery." International Journal of Research in Pharmaceutical Sciences 11, no. 1 (February 5, 2020): 1055–66. http://dx.doi.org/10.26452/ijrps.v11i1.1936.

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In this particular review, it is been noted that Dendrimers are novel three-dimensional globular nano-polymeric structure; having multiple functional groups on the surface enhances their function. Synonymous terms for dendrimer include arborols and cascade molecules. The importance of dendrimers in a large variety of fields has been detected, where the various types of dendrimers helps in various fields of drug delivery with the different types of dendrimers with the generation. Hence the dendrimer gains more attention from researchers among various nano-materials. Convenient synthesis of the structure makes them as a good nano-material for drug delivery. In recent, dendrimers showed their activity in different drug delivery systems having properties like cancer targeting, anti-bacterial, ocular drug delivery, etc.. The future direction about the dendrimers are been discussed. The present review is focused on types of dendrimers like Polypropylene Imine dendrimer (PPI), Poly(amidoamine) dendrimers (PAMAM), Poly-l-lysine dendrimers, Type of Frechet’s dendrimer, Core-shell tecto dendrimers, Chiral dendrimers, Liquid crystalline dendrimers, Peptide dendrimers, Multiple antigen peptide dendrimers, Glyco-dendrimers, Hybrid dendrimers, Polyester dendrimers in which among these type of dendrimers, the Polypropylene Imine dendrimer (PPI) and Poly(amidoamine) dendrimers are found to be good carriers for various targeting site, Dendrimers are synthesized through various methods like Divergent method, Convergent method, Hyper cores and branched monomer growth method, Double exponential growth method, Click chemistry method, recent advances in dendrimers are used in the Anti-cancer delivery, Anti-bacterial delivery, oral route delivery, pulmonary drug delivery, transdermal drug delivery, ocular delivery, and targeted drug delivery the safety aspects, and future strategies are also been discussed in the below article.

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Salvi, Lavish, Chetan Kumar Dubey, Kapil Sharma, Devendra Nagar, Monika Meghani, Saloni Goyal, Jagdish Chandra Nagar, and Archana Sharma. "A Synthesis, Properties and Application as a Possible Drug Delivery Systems Dendrimers – A Review." Asian Journal of Pharmaceutical Research and Development 8, no. 2 (April 13, 2020): 107–13. http://dx.doi.org/10.22270/ajprd.v8i2.676.

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Dendrimer is derived from the Greek word “dendron” which is used for tree and from the Greek suffix “mer” (segment) which describes the synthetic, three-dimensional molecules having branching parts.“A dendrimer is generally described as a macromolecule, which is characterized by its dendritic and hyper branched 3D structure that offers a high degree of surface functionality and versatility.” Dendrimers possess three distinguishable architectural components i.e. an interior core, interior layer(generations) composed of repeating units radially attached to the interior core, and exterior (terminal functionality) attached to outermost interior generation (Fig. 1). The higher generation dendrimers, due to their globular structure, occupy a smaller hydrodynamic volume compared to the corresponding linear polymers. The dendritic structure is characterized by layer between each generation.Dendrimers are generally prepared using either a divergent method or a convergent one. There is a fundamental difference between these two construction concepts. Dendrimers shows the various properties such as structure, shape, aqueous solubility, non-polar solubility, &architecture. Dendrimer can be classification on the basis of their shape, structure, branching, solubility, chirality and attachment. Dendrimer can be differentiated on the basis of their shape, end functional groups and internal cavities.

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Bosch, Paula, Desislava Staneva, Evgenia Vasileva-Tonkova, Petar Grozdanov, Ivanka Nikolova, Rositsa Kukeva, Radostina Stoyanova, and Ivo Grabchev. "New Poly(Propylene Imine) Dendrimer Modified with Acridine and Its Cu(II) Complex: Synthesis, Characterization and Antimicrobial Activity." Materials 12, no. 18 (September 18, 2019): 3020. http://dx.doi.org/10.3390/ma12183020.

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A second-generation poly(propylene imine) dendrimer modified with acridine and its Cu(II) complex have been synthesized for the first time. It has been found that two copper ions form complexes with the nitrogen atoms of the dendrimeric core by coordinate bonds. The new compounds have been characterized by nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), fourier-transform infrared spectroscopy (FTIR) and fluorescence spectroscopy. The spectral characteristics of the modified dendrimer have been measured in different organic solvents, and a negative fluorescence solvatochromism has been observed. The antimicrobial activity of the dendrimers has been tested against model pathogenic microorganisms in agar and by broth dilution method. The cotton fabric treated with both dendrimers has been evaluated towards pathogenic microorganisms. The obtained modified cotton fabrics have been shown to hamper bacterial growth and to prevent biofilm formation. Dendrimer cytotoxicity has been investigated in vitro in the model HEp-2 cell line.

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Rajakumar, Perumal, Kannupal Srinivasan, and Govindasamy Periyasami. "Synthesis of axially chiral dendrimers containing meta-terphenyl peripheral groups and a chiral binol core." Journal of Chemical Research 2005, no. 2 (February 2005): 135–37. http://dx.doi.org/10.3184/0308234054497245.

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Fréchet-type poly(arylether) dendritic bromides carrying m-terphenyl peripheral groups were synthesised up to second generation by convergent methodology. Simple O-alkylation of chiral (S)-BINOL with the dendritic bromides afforded the corresponding axially chiral dendrimers. The molar optical rotation values of the dendrimers become increasingly negative as the dendrimer generation increases.

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Kurbatov, Andrey O., Nikolay K. Balabaev, Mikhail A. Mazo, and Elena Yu Kramarenko. "Adsorption of Silicon-Containing Dendrimers: Effects of Chemical Composition, Structure, and Generation Number." Polymers 13, no. 4 (February 13, 2021): 552. http://dx.doi.org/10.3390/polym13040552.

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We studied the conformational behavior of silicon-containing dendrimers during their adsorption onto a flat impenetrable surface by molecular dynamics (MD) simulations. Four homologous series of dendrimers from the 4th up to the 7th generations were modeled, namely, two types of carbosilane dendrimers differing by the functionality of the core Si atom and two types of siloxane dendrimers with different lengths of the spacers. Comparative analysis of the fractions of adsorbed atoms belonging to various structural layers within dendrimers as well as density profiles allowed us to elucidate not only some general trends but also the effects determined by dendrimer specificity. In particular, it was found that in contrast to the carbosilane dendrimers interacting with the adsorbing surface mainly by their peripheral layers, the siloxane dendrimers with the longer –O–Si(CH3)2–O spacers expose atoms from their interior to the surface spreading out on it. These findings are important for the design of functional materials on the basis of silicon-containing dendrimers.

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Lu, Juan, Nannan Li, Yaochun Gao, Nan Li, Yifei Guo, Haitao Liu, Xi Chen, Chunyan Zhu, Zhengqi Dong, and Akira Yamamoto. "The Effect of Absorption-Enhancement and the Mechanism of the PAMAM Dendrimer on Poorly Absorbable Drugs." Molecules 23, no. 8 (August 10, 2018): 2001. http://dx.doi.org/10.3390/molecules23082001.

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The polyamidoamine (PAMAM) dendrimer is a highly efficient absorption promoter. In the present study, we studied the absorption-enhancing effects and the mechanism of PAMAM dendrimers with generation 0 to generation 3 (G0–G3) and concentrations (0.1–1.0%) on the pulmonary absorption of macromolecules. The absorption-enhancing mechanisms were elucidated by microarray, western blotting analysis, and PCR. Fluorescein isothiocyanate-labeled dextrans (FDs) with various molecular weights were used as model drugs of poorly absorbable drugs. The absorption-enhancing effects of PAMAM dendrimers on the pulmonary absorption of FDs were in a generation- and concentration-dependent manner. The G3 PAMAM dendrimer with high effectiveness was considered to the best absorption enhancer for improving the pulmonary absorption of FDs. G3 PAMAM dendrimers at three different concentrations were non-toxic to Calu-3 cells. Based on the consideration between efficacy and cost, the 0.1% G3 PAMAM dendrimer was selected for subsequent studies. The results showed that treatment with a 0.1% G3 PAMAM dendrimer could increase the secretion of organic cation transporters (OCTs), OCT1, OCT2, and OCT3, which might be related to the absorption-enhancing mechanisms of the pulmonary absorption of FDs. These findings suggested that PAMAM dendrimers might be potentially safe absorption enhancers for improving absorption of FDs by increasing the secretion of OCT1, OCT2, and OCT3.

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Song, Qian Qian, Xiaofeng Zhang, Qiu Feng Huang, and Shen Lin. "Effects of Interaction between PAMAM and Polyoxometalates on Catalytic Performance for Oxidation of Isobutyraldehyde." Advanced Materials Research 610-613 (December 2012): 100–105. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.100.

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G1.0 (Generation1.), G2.0, G3.0, G4.0 polyamidoamine (PAMAM) dendrimers-supported Na5CoII(H2O)PW11O39 (PW11Co) were prepared by co-precipitation method. They were characterized by UV-Vis, XPS, XRD, and TEM. It is suggested that as the generation of the PAMAM dendrimers increased, the interaction between PW11Co and PAMAM dendrimer enhanced and the particle size of PW11Co decreased. The catalytic activities for the oxidation of isobutyraldehyde (IBA) to isobutyric acid (IBAc) by PW11Co-PAMAM(G1.0, G2.0, G3.0, G4.0) were examined.

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Monaco, Olivia N., Sarah C. Tomas, Meghan K. Kirrane, and Amy M. Balija. "Bis(benzylamine) monomers: One-pot preparation and application in dendrimer scaffolds for removing pyrene from aqueous environments." Beilstein Journal of Organic Chemistry 9 (October 31, 2013): 2320–27. http://dx.doi.org/10.3762/bjoc.9.266.

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Bisimine and bisamine AB2 monomers have been synthesized from 3,5-diaminobenzoic acid and benzaldehyde derivatives without the need for protective groups or purification. This monomer preparation is universal for various electron-donating and electron-withdrawing benzaldehyde substrates. To demonstrate the versatility of these previously unreported AB2 monomers in the formation of high molecular weight structures, novel first-generation dendrimers and hybrid second-generation dendrimers have been synthesized. Using fluorescence spectroscopy, pyrene was shown to be removed from an aqueous environment upon exposure to thin dendrimer films, with the first-generation dendrimer removing 70% of the pyrene within 30 min and the hybrid second-generation dendrimers removing 38–52%. Inclusion formation constants were calculated to be on the order of 109–1011 M−1 and are comparable to the values of previously reported macromolecules. These results illustrate that size may not influence pyrene removal as effectively as composition.

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Yamamoto, Kimihisa. "Fine Controlled Metallodendrimers for Advanced Nano-Catalysts." Advances in Science and Technology 72 (October 2010): 261–64. http://dx.doi.org/10.4028/www.scientific.net/ast.72.261.

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Dendrimers are highly branched organic macromolecules with successive layers or “generations” of branch units surrounding a central core. We show that tinchlorides complexes to the imines groups of a spherical polyphenylazomethine dendrimer in a stepwise fashion according to an electron gradient, with complexation in a more peripheral generation proceeding only after complexation in generations closer to the core has been completed. By further extending this strategy, it should be possible to control the number and location of metalchlorides incorporated into dendrimers for advanced nano-materials, such as nano-catalysts.

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Mignani, Serge, Jérôme Bignon, Xiangyang Shi, and Jean-Pierre Majoral. "First-in-Class Phosphorus Dendritic Framework, a Wide Surface Functional Group Palette Bringing Noteworthy Anti-Cancer and Anti-Tuberculosis Activities: What Lessons to Learn?" Molecules 26, no. 12 (June 17, 2021): 3708. http://dx.doi.org/10.3390/molecules26123708.

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Based on phenotypic screening, the major advantages of phosphorus dendrimers and dendrons as drugs allowed the discovery of new therapeutic applications, for instance, as anti-cancer and anti-tuberculosis agents. These biological activities depend on the nature of the chemical groups (neutral or cationic) on their surface as well as their generation. As lessons to learn, in the oncology domain, the increase in the generation of metallo-dendrimers is in the same direction as the anti-proliferative activities, in contrast to the development of polycationic dendrimers, where the most potent anti-tuberculosis phosphorus dendrimer was observed to have the lowest generation (G0). The examples presented in this original analysis of phosphorus dendrimers and dendrons provide support for the lessons learned and for the development of new nanoparticles in nanomedicine.

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Camacho, Cláudia S., Marta Urgellés, Helena Tomás, Fernando Lahoz, and João Rodrigues. "New insights into the blue intrinsic fluorescence of oxidized PAMAM dendrimers considering their use as bionanomaterials." Journal of Materials Chemistry B 8, no. 45 (2020): 10314–26. http://dx.doi.org/10.1039/d0tb01871f.

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The fluorescence intensity of oxidized PAMAM dendrimers is not only dependent on the number of HASLs in the dendrimer scaffold (i.e., on dendrimer generation), but also on the rigidification suffered by the dendrimer due to the acidic environment.

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Chis, Adriana Aurelia, Carmen Dobrea, Claudiu Morgovan, Anca Maria Arseniu, Luca Liviu Rus, Anca Butuca, Anca Maria Juncan, et al. "Applications and Limitations of Dendrimers in Biomedicine." Molecules 25, no. 17 (September 1, 2020): 3982. http://dx.doi.org/10.3390/molecules25173982.

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Biomedicine represents one of the main study areas for dendrimers, which have proven to be valuable both in diagnostics and therapy, due to their capacity for improving solubility, absorption, bioavailability and targeted distribution. Molecular cytotoxicity constitutes a limiting characteristic, especially for cationic and higher-generation dendrimers. Antineoplastic research of dendrimers has been widely developed, and several types of poly(amidoamine) and poly(propylene imine) dendrimer complexes with doxorubicin, paclitaxel, imatinib, sunitinib, cisplatin, melphalan and methotrexate have shown an improvement in comparison with the drug molecule alone. The anti-inflammatory therapy focused on dendrimer complexes of ibuprofen, indomethacin, piroxicam, ketoprofen and diflunisal. In the context of the development of antibiotic-resistant bacterial strains, dendrimer complexes of fluoroquinolones, macrolides, beta-lactamines and aminoglycosides have shown promising effects. Regarding antiviral therapy, studies have been performed to develop dendrimer conjugates with tenofovir, maraviroc, zidovudine, oseltamivir and acyclovir, among others. Furthermore, cardiovascular therapy has strongly addressed dendrimers. Employed in imaging diagnostics, dendrimers reduce the dosage required to obtain images, thus improving the efficiency of radioisotopes. Dendrimers are macromolecular structures with multiple advantages that can suffer modifications depending on the chemical nature of the drug that has to be transported. The results obtained so far encourage the pursuit of new studies.

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Cao, Yiyun, Yao He, Hui Liu, Yu Luo, Mingwu Shen, Jindong Xia, and Xiangyang Shi. "Targeted CT imaging of human hepatocellular carcinoma using low-generation dendrimer-entrapped gold nanoparticles modified with lactobionic acid." Journal of Materials Chemistry B 3, no. 2 (2015): 286–95. http://dx.doi.org/10.1039/c4tb01542h.

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Marradi, Marco, Stefano Cicchi, Francesco Sansone, Alessandro Casnati, and Andrea Goti. "Low-generation dendrimers with a calixarene core and based on a chiral C 2-symmetric pyrrolidine as iminosugar mimics." Beilstein Journal of Organic Chemistry 8 (June 26, 2012): 951–57. http://dx.doi.org/10.3762/bjoc.8.107.

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The preparation of low-generation dendrimers based on a simple calix[4]arene scaffold by insertion of the iminosugar-analogue C 2-symmetric 3,4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation of a considerable number of iminosugar-like moieties in a reduced volume and in a well-defined geometry. The inclusion of alkali-metal ions (sodium and potassium) in the polar cavity defined by the acetamide moieties at the lower rim of the calixarene was demonstrated, which allows also the rigidification of the dendrimer structure and the iminosugar presentation in the clusters. The combination of the supramolecular properties of calixarenes with the advantage of a dendrimeric presentation of repetitive units opens up the possibility of generating well-defined multivalent and multifaceted systems with more complex and/or biologically relevant iminosugars.

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Munshi, Alaa M., Jessica A. Kretzmann, Cameron W. Evans, Anna M. Ranieri, Zibeon Schildkraut, Massimiliano Massi, Marck Norret, Martin Saunders, and K. Swaminathan Iyer. "Dendronised Polymers as Templates for In Situ Quantum Dot Synthesis." Australian Journal of Chemistry 73, no. 7 (2020): 658. http://dx.doi.org/10.1071/ch20071.

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The utility of dendrimers as effective carriers for targeted drug delivery and imaging has been facilitated by a high degree of molecular uniformity, narrow molecular weight distribution, tunable size and shape characteristics, and multivalency. Dendrimer–quantum dot (QD) nanocomposites have traditionally been synthesised by electrostatic self-assembly of preformed dendrimers and QDs, but higher generations are associated with limited flexibility and increased cytotoxicity. In this paper, we report the fabrication of CdTe QD nanoparticles using a dendronised linear copolymer bearing thiolated fourth-generation poly(amido amine) (PAMAM) dendrons as the capping and stabilising agent. We demonstrate this approach enables synthesis of nanocomposites with aqueous and photophysical stability.

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Abd-El-Aziz, Alaa S., Ebtehal G. El-Ghezlani, and Amani A. Abdelghani. "Design of Organoiron Dendrimers Containing Paracetamol for Enhanced Antibacterial Efficacy." Molecules 25, no. 19 (October 2, 2020): 4514. http://dx.doi.org/10.3390/molecules25194514.

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Paracetamol (acetaminophen) is a common painkiller and antipyretic drug used globally. Attachment of paracetamol to a series of organoiron dendrimers was successfully synthesized. The aim of this study is to combine the benefits of the presence of these redox-active organoiron dendrimers, their antimicrobial activities against some human pathogenic Gram-positive, and the therapeutic characteristics of paracetamol. The antimicrobial activity of these dendrimers was investigated and tested with a minimum inhibitory concentration and this has been reported. Some of these newly synthesized dendrimers exhibited the highest inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE), and Staphylococcus warneri compared to reference drugs. The results of this study indicate that the antimicrobial efficacy of the dendrimers is dependent on the size of the redox-active organoiron dendrimer and its terminal functionalities. The best result has been recorded for the fourth-generation dendrimer 11, which attached to 48 paracetamol end groups and has 90 units composed of the η6-aryl-η5-cyclopentadienyliron (II) complex. This dendrimer presented inhibition of 50% of the growth (IC50) of 0.52 μM for MRSA, 1.02 μM for VRE, and 0.73 μM for Staphylococcus warneri. The structures of the dendrimers were characterized by elemental analysis, Fourier transform infrared (FT-IR), nuclear magnetic resonance (1H-NMR), and 13C-NMR spectroscopic techniques. In addition, all synthesized dendrimers displayed good thermal stability in the range of 300–350 °C following the degradation of the cationic iron moieties which occurred around 200 °C.

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Florendo, Maria, Alexander Figacz, Bhairavi Srinageshwar, Ajit Sharma, Douglas Swanson, Gary Dunbar, and Julien Rossignol. "Use of Polyamidoamine Dendrimers in Brain Diseases." Molecules 23, no. 9 (September 3, 2018): 2238. http://dx.doi.org/10.3390/molecules23092238.

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Polyamidoamine (PAMAM) dendrimers are one of the smallest and most precise nanomolecules available today, which have promising applications for the treatment of brain diseases. Each aspect of the dendrimer (core, size or generation, size of cavities, and surface functional groups) can be precisely modulated to yield a variety of nanocarriers for delivery of drugs and genes to brain cells in vitro or in vivo. Two of the most important criteria to consider when using PAMAM dendrimers for neuroscience applications is their safety profile and their potential to be prepared in a reproducible manner. Based on these criteria, features of PAMAM dendrimers are described to help the neuroscience researcher to judiciously choose the right type of dendrimer and the appropriate method for loading the drug to form a safe and effective delivery system to the brain.

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Amin, Shahid, Abaid Ur Rehman Virk, M. A. Rehman, and Nehad Ali Shah. "Analysis of Dendrimer Generation by Sombor Indices." Journal of Chemistry 2021 (May 6, 2021): 1–11. http://dx.doi.org/10.1155/2021/9930645.

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Dendrimers are highly branched, star-shaped macromolecules with nanometer-scale dimensions. Dendrimers are defined by three components: a central core, an interior dendritic structure (the branches), and an exterior surface with functional surface groups. Topological indices are numerical numbers that help us to understand the topology of different dendrimers and can be used to predict the properties without performing experiments in the wet lab. In the present paper, we computed the Sombor index and the reduced version of the Sombor index for the molecular graphs of phosphorus-containing dendrimers, porphyrin-cored dendrimers, PDI-cored dendrimers, triazine-based dendrimers, and aliphatic polyamide dendrimers. We also plotted our results by using Maple 2015 which help us to see the dependence of the Sombor index and reduced Sombor index on the involved parameters. Our results may help to develop better understanding about phosphorus-containing dendrimers, porphyrin-cored dendrimers, PDI-cored dendrimers, triazine-based dendrimers, and aliphatic polyamide dendrimers. Our results are also useful in the pharmaceutical industry and drug delivery.

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Janaszewska, Lazniewska, Trzepiński, Marcinkowska, and Klajnert-Maculewicz. "Cytotoxicity of Dendrimers." Biomolecules 9, no. 8 (August 1, 2019): 330. http://dx.doi.org/10.3390/biom9080330.

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Drug delivery systems are molecular platforms in which an active compound is packed into or loaded on a biocompatible nanoparticle. Such a solution improves the activity of the applied drug or decreases its side effects. Dendrimers are promising molecular platforms for drug delivery due to their unique properties. These macromolecules are known for their defined size, shape, and molecular weight, as well as their monodispersity, the presence of the void space, tailorable structure, internalization by cells, selectivity toward cells and intracellular components, protection of guest molecules, and controllable release of the cargo. Dendrimers were tested as carriers of various molecules and, simultaneously, their toxicity was examined using different cell lines. It was discovered that, in general, dendrimer cytotoxicity depended on the generation, the number of surface groups, and the nature of terminal moieties (anionic, neutral, or cationic). Higher cytotoxicity occurred for higher-generation dendrimers and for dendrimers with positive charges on the surface. In order to decrease the cytotoxicity of dendrimers, scientists started to introduce different chemical modifications on the periphery of the nanomolecule. Dendrimers grafted with polyethylene glycol (PEG), acetyl groups, carbohydrates, and other moieties did not affect cell viability, or did so only slightly, while still maintaining other advantageous properties. Dendrimers clearly have great potential for wide utilization as drug and gene carriers. Moreover, some dendrimers have biological properties per se, being anti-fungal, anti-bacterial, or toxic to cancer cells without affecting normal cells. Therefore, intrinsic cytotoxicity is a comprehensive problem and should be considered individually depending on the potential destination of the nanoparticle.

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Abd-El-Aziz, Alaa S., Amani A. Abdelghani, Brian D. Wagner, and Elsayed M. Abdelrehim. "Aggregation enhanced excimer emission (AEEE) with efficient blue emission based on pyrene dendrimers." Polymer Chemistry 7, no. 19 (2016): 3277–99. http://dx.doi.org/10.1039/c6py00443a.

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A series of fluorescent dendrimers with pyrene moieties exhibited aggregation enhanced excimer emission (AEEE). Increases in the dendrimer generation caused emission at 480 nm with a high excimer/monomer emission intensity ratio.

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Vanbellingen, Quentin, Paul Servin, Anaïs Coinaud, Sonia Mallet-Ladeira, Régis Laurent, and Anne-Marie Caminade. "Dendrimers Functionalized with Palladium Complexes of N-, N,N-, and N,N,N-Ligands." Molecules 26, no. 8 (April 17, 2021): 2333. http://dx.doi.org/10.3390/molecules26082333.

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Pyridine, pyridine imine, and bipyridine imine ligands functionalized by a phenol have been synthesized and characterized, in many cases by X-ray diffraction. Several of these N-, N,N-, and N,N,N,-ligands have been grafted onto the surface of phosphorhydrazone dendrimers, from generation 1 to generation 3. The complexation ability of these monomers and dendrimers towards palladium(II) has been assayed. The corresponding complexes have been either isolated or prepared in situ. In both cases, the monomeric and dendritic complexes have been tested as catalysts in Heck couplings and in Sonogashira couplings. In some cases, a positive dendritic effect has been observed, that is, an increase of the catalytic efficiency proportional to the dendrimer generation.

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32

Zhang, Songbai, Vega Lloveras, Daniel Pulido, Flonja Liko, Luiz F. Pinto, Fernando Albericio, Miriam Royo, and José Vidal-Gancedo. "Radical Dendrimers Based on Biocompatible Oligoethylene Glycol Dendrimers as Contrast Agents for MRI." Pharmaceutics 12, no. 8 (August 14, 2020): 772. http://dx.doi.org/10.3390/pharmaceutics12080772.

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Finding alternatives to gadolinium (Gd)-based contrast agents (CA) with the same or even better paramagnetic properties is crucial to overcome their established toxicity. Herein we describe the synthesis and characterization of entirely organic metal-free paramagnetic macromolecules based on biocompatible oligoethylene glycol dendrimers fully functionalized with 5 and 20 organic radicals (OEG Gn-PROXYL (n = 0, 1) radical dendrimers) with the aim to be used as magnetic resonance imaging (MRI) contrast agents. Conferring high water solubility on such systems is often a concern, especially in large generation dendrimers. Our approach to overcome such an issue in this study is by synthesizing dendrimers with highly water-soluble branches themselves. In this work, we show that the highly water-soluble OEG Gn-PROXYL (n = 0, 1) radical dendrimers obtained showed properties that convert them in good candidates to be studied as contrast agents for MRI applications like diagnosis and follow-up of infectious diseases, among others. Importantly, with the first generation radical dendrimer, a similar r1 relaxivity value (3.4 mM−1s−1) in comparison to gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) used in clinics (3.2 mM−1s−1, r.t. 7T) has been obtained, and it has been shown to not be cytotoxic, avoiding the toxicity risks associated with the unwanted accumulation of Gd in the body.

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33

Kurbatov, Andrey, Nikolay Balabaev, Mikhail Mazo, and Elena Kramarenko. "A Comparative Study of Intramolecular Mobility of Single Siloxane and Carbosilane Dendrimers via Molecular Dynamics Simulations." Polymers 10, no. 8 (July 30, 2018): 838. http://dx.doi.org/10.3390/polym10080838.

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A comparative analysis of intramolecular dynamics of four types of isolated dendrimers from the fourth to the seventh generations belonging to the siloxane and carbosilane families, differing in spacer length, core functionality, and the type of chemical bonds, has been performed via atomic molecular dynamics simulations. The average radial and angular positions of all Si branching atoms of various topological layers within the dendrimer interior, as well as their variations, have been calculated, and the distributions of the relaxation times of their radial and angular motions have been found. It has been shown that the dendrons of all the dendrimers elongate from the center and decrease in a solid angle with an increasing generation number. The characteristic relaxation times of both angular and radial motions of Si atoms are of the order of a few nanoseconds, and they increase with an increasing generation number and decrease with temperature, with the angular relaxation times being larger than the radial ones. The relaxation times in the carbosilanes are larger than those in the siloxanes. The rotational angle dynamics of the carbosilane dendrimers show that the chain bending is mainly realized via trans-gauche transitions in the Si branching bonds.

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Tikhonov, Pavel A., Nataliya G. Vasilenko, Marat O. Gallyamov, Georgii V. Cherkaev, Viktor G. Vasil’ev, Nina V. Demchenko, Mikhail I. Buzin, Sergey G. Vasil’ev, and Aziz M. Muzafarov. "Multiarm Star-Shaped Polydimethylsiloxanes with a Dendritic Branching Center." Molecules 26, no. 11 (May 29, 2021): 3280. http://dx.doi.org/10.3390/molecules26113280.

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New multiarm stars have been synthesized based on polylithium derivatives of high-generation carbosilane dendrimers. In the synthesis of multiarm stars based on the eighth-generation dendrimer, steric hindrances were observed even during the synthesis of a polylithium initiator. Subsequently, this led to chain transfer reactions between growing arms, as well as other side effects. As a result, dense nanogel formations with a higher tendency of ordering than in classical objects of this type were isolated from the reaction mixture. The study of the rheology of multiarm stars based on sixth-generation dendrimers made it possible to determine the activation energies of viscous flow in these objects, which makes it possible to consider them as objects with a macromolecular nature and a reptation flow mechanism.

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35

Pai, Chin-Ling, Ming-Jium Shieh, Pei-Jen Lou, Fei-Hong Huang, Tzu-Wen Wang, and Ping-Shan Lai. "Characterization of the Uptake and Intracellular Trafficking of G4 Polyamidoamine Dendrimers." Australian Journal of Chemistry 64, no. 3 (2011): 302. http://dx.doi.org/10.1071/ch10358.

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Polyamidoamine (PAMAM) dendrimers are highly branched spherical polymers that have emerged as potent synthetic drug and gene carriers; however, much remains to be learned about the mechanism of dendrimer-mediated cellular uptake. In this study, the endocytic pathway and intracellular trafficking of generation 4 (G4) PAMAM dendrimers were evaluated via fluorescein isothiocyanate (FITC) conjugation. We found that the G4-FITC dendrimers were internalized by energy-dependent and non-specific endocytic pathways. Interesting, G4-FITC dendrimers can not only buffer the endosomal/lysosomal pH but also co-localize with lysosomal markers over a period of 3 to 12 h, after which the signal decreased in the lysosomes and began to co-localize with the mitochondrial marker. This study contributes to the understanding of the molecular behaviour of G4 PAMAM dendrimers in a cellular environment and will facilitate the development of more effective PAMAM-mediated drug and gene delivery systems.

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Michlewska, Sylwia, Maksim Ionov, Aleksandra Szwed, Aneta Rogalska, Natalia Sanz del Olmo, Paula Ortega, Marta Denel, et al. "Ruthenium Dendrimers against Human Lymphoblastic Leukemia 1301 Cells." International Journal of Molecular Sciences 21, no. 11 (June 9, 2020): 4119. http://dx.doi.org/10.3390/ijms21114119.

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Ruthenium atoms located in the surfaces of carbosilane dendrimers markedly increase their anti-tumor properties. Carbosilane dendrimers have been widely studied as carriers of drugs and genes owing to such characteristic features as monodispersity, stability, and multivalence. The presence of ruthenium in the dendrimer structure enhances their successful use in anti-cancer therapy. In this paper, the activity of dendrimers of generation 1 and 2 against 1301 cells was evaluated using Transmission Electron Microscopy, comet assay and Real Time PCR techniques. Additionally, the level of reactive oxygen species (ROS) and changes of mitochondrial potential values were assessed. The results of the present study show that ruthenium dendrimers significantly decrease the viability of leukemia cells (1301) but show low toxicity to non-cancer cells (peripheral blood mononuclear cells—PBMCs). The in vitro test results indicate that the dendrimers injure the 1301 leukemia cells via the apoptosis pathway.

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37

Szwed, Aleksandra, Katarzyna Miłowska, Sylwia Michlewska, Silvia Moreno, Dzmitry Shcharbin, Rafael Gomez-Ramirez, Francisco Javier de la Mata, Jean-Pierre Majoral, Maria Bryszewska, and Teresa Gabryelak. "Generation Dependent Effects and Entrance to Mitochondria of Hybrid Dendrimers on Normal and Cancer Neuronal Cells In Vitro." Biomolecules 10, no. 3 (March 9, 2020): 427. http://dx.doi.org/10.3390/biom10030427.

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Dendrimers as drug carriers can be utilized for drugs and siRNA delivery in central nervous system (CNS) disorders, including various types of cancers, such as neuroblastomas and gliomas. They have also been considered as drugs per se, for example as anti-Alzheimer’s disease (AD), anti-cancer, anti-prion or anti-inflammatory agents. Since the influence of carbosilane–viologen–phosphorus dendrimers (SMT1 and SMT2) on the basic cellular processes of nerve cells had not been investigated, we examined the impact of two generations of these hybrid macromolecules on two murine cell lines—cancer cell line N2a (mouse neuroblastoma) and normal immortalized cell line mHippoE-18 (embryonic mouse hippocampal cell line). We examined alterations in cellular responses including the activity of mitochondrial dehydrogenases, the generation of reactive oxygen species (ROS), changes in mitochondrial membrane potential, and morphological modifications and fractions of apoptotic and dead cells. Our results show that both dendrimers at low concentrations affected the cancer cell line more than the normal one. Also, generation-dependent effects were found: the highest generation induced greater cytotoxic effects and morphological modifications. The most promising is that the changes in mitochondrial membrane potential and transmission electron microscopy (TEM) images indicate that dendrimer SMT1 can reach mitochondria. Thus, SMT1 and SMT2 seem to have potential as nanocarriers to mitochondria or anti-cancer drugs per se in CNS disorders.

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Rajavelu, Kannan, Perumal Rajakumar, Mandal Sudip, and Ramanujam Kothandaraman. "Synthesis, photophysical, electrochemical, and DSSC application of novel donor–acceptor triazole bridged dendrimers with a triphenylamine core and benzoheterazole as a surface unit." New Journal of Chemistry 40, no. 12 (2016): 10246–58. http://dx.doi.org/10.1039/c6nj02126c.

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Triazole bridged novel donor–acceptor dendrimers were synthesized via click chemistry. Lower generation dendrimers when used as additives exhibit better current-generating capacity and power conversion efficiency in DSSCs.

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39

Sanz del Olmo, Natalia, Cornelia E. Peña González, Jose Daniel Rojas, Rafael Gómez, Paula Ortega, Alberto Escarpa, and Francisco Javier de la Mata. "Antioxidant and Antibacterial Properties of Carbosilane Dendrimers Functionalized with Polyphenolic Moieties." Pharmaceutics 12, no. 8 (July 24, 2020): 698. http://dx.doi.org/10.3390/pharmaceutics12080698.

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A new family of polyphenolic carbosilane dendrimers functionalized with ferulic, caffeic, and gallic acids has been obtained through a straightforward amidation reaction. Their antioxidant activity has been studied by different techniques such as DPPH (2,2′-diphenyl-1-picrylhydrazyl) radical scavenging assay, FRAP assay (ferric reducing antioxidant power), and cyclic voltammetry. The antioxidant analysis showed that polyphenolic dendrimers exhibited higher activities than free polyphenols in all cases. The first-generation dendrimer decorated with gallic acid stood out as the best antioxidant compound, displaying a correlation between the number of hydroxyl groups in the polyphenol structure and the antioxidant activity of the compounds. Moreover, the antibacterial capacity of these new systems has been screened against Gram-positive (+) and Gram-negative (−) bacteria, and we observed that polyphenolic dendrimers functionalized with caffeic and gallic acids were capable of decreasing bacterial growth. In contrast, ferulic carbosilane dendrimers and free polyphenols showed no effect, establishing a correlation between antioxidant activity and antibacterial capacity. Finally, a viability assay in human skin fibroblasts cells (HFF-1) allowed for corroborating the nontoxicity of the polyphenolic dendrimers at their active antibacterial concentration.

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Concellón, Alberto, María San Anselmo, Silvia Hernández-Ainsa, Pilar Romero, Mercedes Marcos, and José Luis Serrano. "Micellar Nanocarriers from Dendritic Macromolecules Containing Fluorescent Coumarin Moieties." Polymers 12, no. 12 (November 30, 2020): 2872. http://dx.doi.org/10.3390/polym12122872.

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The design of efficient drug-delivery vehicles remains a big challenge in materials science. Herein, we describe a novel class of amphiphilic hybrid dendrimers that consist of a poly(amidoamine) (PAMAM) dendritic core functionalized with bisMPA dendrons bearing cholesterol and coumarin moieties. Their self-assembly behavior both in bulk and in water was investigated. All dendrimers exhibited smectic A or hexagonal columnar liquid crystal organizations, depending on the generation of the dendrimer. In water, these dendrimers self-assembled to form stable spherical micelles that could encapsulate Nile Red, a hydrophobic model compound. The cell viability in vitro of the micelles was studied in HeLa cell line, and proved to be non-toxic up to 72 h of incubation. Therefore, these spherical micelles allow the encapsulation of hydrophobic molecules, and at the same time provided fluorescent traceability due to the presence of coumarin units in their chemical structure, demonstrating the potential of these dendrimers as nanocarriers for drug-delivery applications.

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Shishu and Manjul Maheshwari. "Dendrimers: The Novel Pharmaceutical Drug Carriers." International Journal of Pharmaceutical Sciences and Nanotechnology 2, no. 2 (August 31, 2009): 493–502. http://dx.doi.org/10.37285/ijpsn.2009.2.2.1.

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Dendrimers represent a novel class of structurally controlled macromolecules derived from a branches-upon-branches structural motif. These consist of well defined, highly branched moieties that radiate from a central core and are synthesized through a stepwise, repetitive reaction sequence that guarantees complete shells for each generation, leading to formation of monodisperse polymers. The synthetic procedures developed for dendrimer preparation permit nearly complete control over the critical molecular design parameters, such as size, shape, surface/interior chemistry, flexibility, and topology by virtue of which these macromolecules offer diverse applications in drug delivery, solubility enhancement, gene therapy and diagnostic field. This article provides an insight into the structure, synthesis, properties, types and the applications of dendrimers in the bio-medical field.

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42

Ceroni, Paola, Veronica Vicinelli, Mauro Maestri, Vincenzo Balzani, Marius Gorka, Sang-Kyu Lee, Patrick Dragut, and Fritz Vögtle. "Poly(propylene amine) Dendrimers Decorated with Dimethoxybenzene Units. Photophysical and Electrochemical Properties." Collection of Czechoslovak Chemical Communications 68, no. 8 (2003): 1541–54. http://dx.doi.org/10.1135/cccc20031541.

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We have investigated the absorption spectra, the fluorescence spectra and decay and the electrochemical redox processes of five dendrimers Gn (n = 1 to 5) that contain 2n+1 - 2 (i.e., 62 for G5) tertiary amino groups in the interior and 2n+1 (i.e., 64 for G5) 1,2-dimethoxybenzene (DMB) units in the periphery. In dichloromethane solution the absorption spectrum of the dendrimers is quite similar to that of 3,4-dimethoxy-N-propylbenzene-1- sulfonamide, a model compound of the peripheral DMB units. The fluorescence band of the DMB unit (λmax = 319 nm, τ = 0.95 ns, Φ = 0.08 for the model compound), however, is much weaker in the dendrimers, which also display a broad emission tail above 450 nm (τ from 2 to 7 ns, depending on dendrimer generation), assigned to exciplex formation between the peripheral dimethoxybenzene groups and the inner tertiary amino groups. Upon addition of trifluoroacetic acid, which causes protonation of the inner amino groups of the dendrimers, the intensity of exciplex emission decreases and the intensity of the 319 nm band of the DMB units increases, reaches a maximum, and then decreases with increasing protonation of the dendrimer interior, presumably because of excimer formation between peripheral DMB units. Electrochemical investigations have shown that in acetonitrile the dendrimers exhibit a reversible, multielectron oxidation wave at about +1.7 V vs SCE, assigned to the peripheral DMB units and broad anodic peaks in the region +0.8/+1.5 V, assigned to oxidation of the inner tertiary amino groups.

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Rajavelu, Kannan, Mamangam Subaraja, and Perumal Rajakumar. "Synthesis, optical properties, and antioxidant and anticancer activity of benzoheterazole dendrimers with triazole bridging unit." New Journal of Chemistry 42, no. 5 (2018): 3282–92. http://dx.doi.org/10.1039/c7nj04060a.

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Benzoheterazole dendrimers with triazole bridges and bisphenol A/benzophenone core units have been successfully synthesized by click chemistry. Higher generation dendrimers exhibit better antioxidant and anticancer activities than the lower generation dendrimers.

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Juris, Alberto, Margherita Venturi, Paola Ceroni, Vincenzo Balzani, Sebastiano Campagna, and Scolastica Serroni. "Dendrimers Based on Electroactive Metal Complexes. A Review of Recent Advances." Collection of Czechoslovak Chemical Communications 66, no. 1 (2001): 1–32. http://dx.doi.org/10.1135/cccc20010001.

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Recent studies in the field of dendrimers based on electroactive metal complexes are reviewed. The electroactive units may be present (i) in the core, (ii) in the branches, (iii) in the surface, (iv) in the core and in the branches, (v) in the core and in the surface, (vi) in the branches and in the surface, and (vii) in the core, branches and surface. Depending on the dendrimer structure, the electroactive units can either interact or behave independently. The most interesting features are the shielding of electroactive cores by non electroactive branches, the great number of electrons that can be exchanged in a very narrow potential region by high generation surface-functionalized dendrimers, and the tailor-made redox patterns that can be obtained by dendrimers based on metal complexes at each branching centre. A review with 42 references.

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MU, TING, DACHENG FENG, and SHENGYU FENG. "A MOLECULAR MODELING STUDY OF GENERATION-DEPENDENT STABILITY OF DENDRITIC POLYSILANES." Journal of Theoretical and Computational Chemistry 07, no. 05 (October 2008): 923–31. http://dx.doi.org/10.1142/s021963360800426x.

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This paper focuses on the maximum generation issue. Molecular dynamics simulations have been employed to search the minimum energy configurations of eight types of structurally related polysilane dendrimers of various generations. Calculations reveal that for the studied dendrimers, the innermost Si – Si bonds adjoining the silicon atom at the center of the core structure are extended for steric relief with the amount of extension increasing with the number of generations due to the rise of the spatial hindrance inside these molecules.

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Zhang, Mengen, Jingyi Zhu, Yun Zheng, Rui Guo, Shige Wang, Serge Mignani, Anne-Marie Caminade, Jean-Pierre Majoral, and Xiangyang Shi. "Doxorubicin-Conjugated PAMAM Dendrimers for pH-Responsive Drug Release and Folic Acid-Targeted Cancer Therapy." Pharmaceutics 10, no. 3 (September 19, 2018): 162. http://dx.doi.org/10.3390/pharmaceutics10030162.

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We present here the development of multifunctional doxorubicin (DOX)-conjugated poly(amidoamine) (PAMAM) dendrimers as a unique platform for pH-responsive drug release and targeted chemotherapy of cancer cells. In this work, we covalently conjugated DOX onto the periphery of partially acetylated and folic acid (FA)-modified generation 5 (G5) PAMAM dendrimers through a pH-sensitive cis-aconityl linkage to form the G5.NHAc-FA-DOX conjugates. The formed dendrimer conjugates were well characterized using different methods. We show that DOX release from the G5.NHAc-FA-DOX conjugates follows an acid-triggered manner with a higher release rate under an acidic pH condition (pH = 5 or 6, close to the acidic pH of tumor microenvironment) than under a physiological pH condition. Both in vitro cytotoxicity evaluation and cell morphological observation demonstrate that the therapeutic activity of dendrimer-DOX conjugates against cancer cells is absolutely related to the DOX drug released. More importantly, the FA conjugation onto the dendrimers allowed a specific targeting to cancer cells overexpressing FA receptors (FAR), and allowed targeted inhibition of cancer cells. The developed G5.NHAc-FA-DOX conjugates may be used as a promising nanodevice for targeted cancer chemotherapy.

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Ceroni, Paola, and Margherita Venturi. "Photoactive and Electroactive Dendrimers: Future Trends and Applications." Australian Journal of Chemistry 64, no. 2 (2011): 131. http://dx.doi.org/10.1071/ch10326.

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The initial interest in dendrimer chemistry was the synthesis of such aesthetically pleasant macromolecules. Nowadays, the field is moving to applications in various multidisciplinary areas, such as medicine, biology, chemistry, physics, and engineering, i.e. at the interface of many disciplines. This short review describes some promising applications of photoactive and electroactive dendrimers as artificial enzymes, molecular batteries, sensors with signal amplification, photoswitchable hosts, systems for energy up-conversion, and light-harvesting antennas. The reported examples clearly show that these applications take advantage of the unique aspects of dendrimer structure: (i) three-dimensional array; (ii) generation-dependent size; (iii) presence of selected functional units in predetermined sites; and (iv) endo- and exo-receptor capabilities.

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Meijboom, Reinout, John R. Moss, Alan T. Hutton, Tracy-Ann Makaluza, Selwyn F. Mapolie, Fazlin Waggie, and Mark R. Domingo. "Hydrozirconation of first-generation allyl-functionalized dendrimers and dendrimer model compounds." Journal of Organometallic Chemistry 689, no. 11 (June 2004): 1876–81. http://dx.doi.org/10.1016/j.jorganchem.2004.03.010.

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Savithri, Jothinathan Sathiya, and Perumal Rajakumar. "Synthesis, Photophysical, and Antioxidant Properties of Rhodamine B Decorated Novel Dendrimers." Australian Journal of Chemistry 71, no. 6 (2018): 399. http://dx.doi.org/10.1071/ch17652.

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Novel triazole bridged dendrimers with rhodamine B derivative as surface groups have been achieved using click chemistry by both divergent and convergent approaches. Rhodamine B decorated dendrimers 1, 2, and 3 were synthesised up to the second generation with spirolactam grafted at the terminal. The UV and fluorescence intensity increases with the increase in the dendritic generation. The synthesised rhodamine B decorated dendrimers show significant antioxidant behaviour compared with the standards butylated hydroxy toluene (BHT) and gallic acid when tested by 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging assay and hydroxyl radical scavenging assay methods, respectively. Rhodamine B decorated higher generation dendrimers exhibit better antioxidant activity than the lower generation dendrimers due to the presence of a greater number of triazole branching units and rhodamine B derivative surface units.

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Vasile, E., A. Serafim, D. Petre, D. Giol, P. Dubruel, H. Iovu, and I. C. Stancu. "Direct Synthesis and Morphological Characterization of Gold-Dendrimer Nanocomposites Prepared Using PAMAM Succinamic Acid Dendrimers: Preliminary Study of the Calcification Potential." Scientific World Journal 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/103462.

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Gold-dendrimer nanocomposites were obtained for the first time by a simple colloidal approach based on the use of polyamidoamine dendrimers with succinamic acid terminal groups and dodecanediamine core. Spherical and highly crystalline nanoparticles with dimensions between 3 nm and 60 nm, and size-polydispersity depending on the synthesis conditions, have been generated. The influence of the stoichiometric ratio and the structural and architectural features of the dendrimers on the properties of the nanocomposites has been described. The self-assembling behaviour of these materials produces gold-dendrimer nanostructured porous networks with variable density, porosity, and composition. The investigations of the reaction systems, by TEM, at two postsynthesis moments, allowed to preliminary establish the control over the properties of the nanocomposite products. Furthermore, this study allowed better understanding of the mechanism of nanocomposite generation. Impressively, in the early stages of the synthesis, the organization of gold inside the dendrimer molecules has been evidenced by micrographs. Growth and ripening mechanisms further lead to nanoparticles with typical characteristics. The potential of such nanocomposite particles to induce calcification when coating a polymer substrate was also investigated.

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Journal articles on the topic 'GENERATION DENDRIMERS'

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