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International audience; In the continuation of our sustained interest for porphyrin-based dendrimers and their use as luminescent photo-sensitizers for two-photon photodynamic therapy (2P-PDT), we wondered about the effect of changing the central porphyrin core for a phthalocyanine core in these macromolecular structures. Thus, related phthalocyanine-based dendrimers possessing up to 16 conjugated 9,9-dibutyl-2-fluorenyl endgroups at their periphery were now prepared and studied. As for porphyrin analogues, it was found that an efficient energy transfer occurs from the peripheral fluorenyl units toward the central phthalocyanine unit of these compounds, leading to intense red light emission and photosensitization of oxygen. While the linear optical properties of these new dendrimers are only slightly improved compared to those of their porphyrin-cored analogues for PDT and fluorescence imaging, their two-photon absorption (2PA) cross-sections are much more significantly boosted, evidencing the key role played by the central tetrapyrrolic unit in this respect. The impact of this structural change in relation with the impact resulting from the change in dendrimer generations is then discussed with the help of DFT and molecular dynamic calculations.

International audience; Dendrimers, notable for their well-defined radial structures with numerous terminal functionalities, hold great promise for biomedical applications such as drug delivery, diagnostics, and therapeutics. However, their translation into clinical use has been greatly impeded by their challenging stepwise synthesis and difficult purification.To circumvent these obstacles, we have pioneered a self-assembly approach to constructing noncovalent supramolecular dendrimers using small amphiphilic dendrimer building units which can be easily synthesized and purified. By virtue of their amphipathic nature, the small amphiphilic dendrimers are able to self-assemble and generate large supramolecular dendrimers via noncovalent weak interactions such as van der Waals forces, H bonds, and electrostatic interactions. The so-created noncovalent dendrimers can mimic covalent dendrimers not only in terms of the radial structural feature emanating from a central core but also in their capacity to deliver drugs and imaging agents for biomedical applications. The noncovalent supramolecular dendrimers can be easily synthesized and modulated with regard to size, shape, and properties by varying the nature of the hydrophobic and hydrophilic entities as well as the dendrimer generation and terminal functionalities, ensuring their adaptability to specific applications. In particular, the dendritic structure of the amphiphilic building units permits the creation of large void spaces within the formed supramolecular dendrimers for the physical encapsulation of drugs, while the large number of surface functionalities can be exploited for both physical and chemical conjugation of pharmaceutic agents for drug delivery.Poly(amidoamine) (PAMAM) dendrimers are the most intensively studied for biomedical applications by virtue of their excellent biocompatibility imparted by their peptide-mimicking amide backbones and numerous interior and terminal amine functionalities. We present a short overview of our self-assembly strategy for constructing supramolecular PAMAM dendrimers for biomedical applications. Specifically, we start with the introduction of dendrimers and their synthesis, focusing on the innovative self-assembly synthesis of supramolecular dendrimers. We then detail the representative examples of the noncovalent supramolecular PAMAM dendrimers established in our group for the delivery of anticancer drugs, nucleic acid therapeutics, and imaging agents, either within the dendrimer interior or at the dendrimer terminals on the surface. Some of the supramolecular dendrimer nanosystems exhibit outstanding performance, excelling the corresponding clinical anticancer therapeutics and imaging agents. This self-assembly approach to creating supramolecular dendrimers is completely novel in concept yet easy to implement in practice, offering a fresh perspective for exploiting the advantageous features of dendrimers in biomedical applications.

Dendrons are an important class of macromolecules that can be used for a broad range of applications. Recent studies have indicated that mixtures of oligoglycerol detergent (OGD) regioisomers are superior to individual regioisomers for protein extraction. The origin of this phenomenon remains puzzling. Here we discuss the synthesis and characterization of dendritic oligoglycerol regioisomer mixtures and their implementation into detergents. We provide experimental benchmarks to support quality control after synthesis and investigate the unusual utility of OGD regioisomer mixtures for extracting large protein quantities from biological membranes. We anticipate that our findings will enable the development of mixed detergent platforms in the future., The secret lies in the mix: Regioisomer mixtures of dendritic oligoglycerol detergents have recently attracted attention from experimentalist in membrane protein research. The present study outlines the synthesis of detergent regioisomer mixtures and sheds light on their utility for the purification of membrane proteins. The obtained results point to new avenues for the development of lipid‐like detergent mixtures in membrane protein research.

International audience; The long-term treatment of tuberculosis (TB) sometimes leads to nonadherence to treatment, resulting in multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. Inadequate bioavailability of the drug is the main factor for therapeutic failure, which leads to the development of drug-resistant cases. Therefore, there is an urgent need to design and develop novel antimycobacterial agents minimizing the period of treatment and reducing the propagation of resistance at the same time. Here, we report the development of original and noncytotoxic polycationic phosphorus dendrimers essentially of generations 0 and 1, but also of generations 2–4, with pyrrolidinium, piperidinium, and related cyclic amino groups on the surface, as new antitubercular agents active per se, meaning with intrinsic activity. The strategy is based on the phenotypic screening of a newly designed phosphorus dendrimer library (generations 0–4) against three bacterial strains: attenuated Mycobacterium tuberculosis H37Ra, virulent M. tuberculosis H37Rv, and Mangora bovis BCG. The most potent polycationic phosphorus dendrimers 1G0,HCl and 2G0,HCl are active against all three strains with minimum inhibitory concentrations (MICs) between 3.12 and 25.0 μg/mL. Both are irregularly shaped nanoparticles with highly mobile branches presenting a radius of gyration of 7 Å, a diameter of maximal 25 Å, and a solvent-accessible surface area of dominantly positive potential energy with very localized negative patches arising from the central N3P3 core, which steadily interacts with water molecules. The most interesting is 2G0,HCl, showing relevant efficacy against single-drug-resistant (SDR) M. tuberculosis H37Rv, resistant to rifampicin, isoniaid, ethambutol, or streptomycin. Importantly, 2G0,HCl displayed significant in vivo efficacy based on bacterial counts in lungs of infected Balb/C mice at a dose of 50 mg/kg oral administration once a day for 2 weeks and superior efficacy in comparison to ethambutol and rifampicin. This series of polycationic phosphorus dendrimers represents first-in-class drugs to treat TB infection, could fulfill the clinical candidate pipe of this high burden of infectious disease, and play a part in addressing the continuous demand for new drugs.

International audience; Nanomedicine represents a very significant contribution in current cancer treatment; in addition to surgical intervention, radiation and chemotherapeutic agents that unfortunately also kill healthy cells, inducing highly deleterious and often life-threatening side effects in the patient. Of the numerous nanoparticles used against cancer, gold nanoparticles had been developed for therapeutic applications. Inter alia, a large variety of dendrimers, i.e. soft artificial macromolecules, have turned up as non-viral functional nanocarriers for entrapping drugs, imaging agents, and targeting molecules. This review will provide insights into the design, synthesis, functionalization, and development in biomedicine of engineered functionalized hybrid dendrimer-tangled gold nanoparticles in the domain of cancer theranostic. Several aspects are highlighted and discussed such as 1) dendrimer-entrapped gold(0) hybrid nanoparticles for the targeted imaging and treatment of cancer cells, 2) dendrimer encapsulating gold(0) nanoparticles (Au DENPs) for the delivery of genes, 3) Au DENPs for drug delivery applications, 4) dendrimer encapsulating gold radioactive nanoparticles for radiotherapy, and 5) dendrimer/dendron-complexed gold(III) nanoparticles as technologies to take down cancer cells.

International audience; Polymeric micelles are nanoassemblies that are formed by spontaneous arrangement of amphiphilic block copolymers in aqueous solutions at critical micelle concentration (CMC). They represent an effective system for drug delivery of, for instance, poorly water-soluble anticancer drugs. Then, the development of polyion complexes (PICs) were emphasized. The morphology of these complexes depends on the topology of the polyelectrolytes used and the way they are assembled. For instance, ionic-hydrophilic block copolymers have been used for the preparation of PIC micelles. The main limitation in the use of PIC micelles is their potential instability during the self-assembly/disassembly processes, influenced by several parameters, such as polyelectrolyte concentration, deionization associated with pH, ionic strength due to salt medium effects, mixing ratio, and PIC particle cross-linking. To overcome these issues, the preparation of stable PIC micelles by increasing the rigidity of their dendritic architecture by the introduction of dendrimers and controlling their number within micelle scaffold was highlighted. In this original concise Review, we will describe the preparation, molecular characteristics, and pharmacological profile of these stable nanoassemblies.

International audience; Dendrimers are macromolecules with well-defined, homogeneous, and monodispersed structures that form a branch-like structure. In general, they have a symmetric core, inner shells, and an outer shell. Over the past decade, metallodendritic architectures have developed into a new area in nanomedicine. Due to their versatility and facile customization, phosphorus dendrimers represent interesting platforms for biomedical applications. Metallo-conjugated phosphorus dendrimers have been developed within the dendrimer space, an important part of the chemical space. The first investigation was made using phosphorus dendrimers bearing copper(II) groups on their surface as the original anticancer drug candidates. The aim of this minireview is to present our powerful strategy to find and develop original multivalent copper(II)-conjugated phosphorus dendrimers. The most potent of them is G3 dendrimers with N-(pyridine-2-ylmethylene)ethanamine as the chelating motif complexed with Cu(II) (1G3-Cu), showing very good in vitro and in vivo antiproliferative efficacy. On the basis of these results, 1G3-Cu is a potential clinical candidate having progressed from hit to preclinical candidate status.

International audience; We designed and synthesized several families of novel amphiphilic fluorescent phosphorus dendron-based micelles showing relevant antiproliferative activities for use in the field of theranostic nanomedicine. Based on straightforward synthesis pathways, 12 amphiphilic phosphorus dendrons bearing 10 protonated cyclic amino groups (generation one), or 20 protonated amino groups (generation two), and 1 hydrophobic chain carrying 1 fluorophore moiety were created. The amphiphilic dendron micelles had the capacity to aggregate in solution using hydrophilic/hydrophobic interactions, which promoted the formation of polymeric micelles. These dendron-based micelles showed moderate to high antiproliferative activities against a panel of tumor cell lines. This paper presents for the first time the synthesis and our first investigations of new phosphorus dendron-based micelles for cancer therapy applications.

International audience; To the best of our knowledge, this is the very first time that a thorough study of the synthetic procedures, molecular and thermal characterization, followed by structure/properties relationship for symmetric and non-symmetric second generation (2-G) dendritic terpolymers is reported. Actually, the synthesis of the non-symmetric materials is reported for the first time in the literature. Anionic polymerization enables the synthesis of well-defined polymers that, despite the architecture complexity, absolute control over the average molecular weight, as well as block composition, is achieved. The dendritic type macromolecular architecture affects the microphase separation, because different morphologies are obtained, which do not exhibit long range order, and various defects or dislocations are evident attributed to the increased number of junction points of the final material despite the satisfactory thermal annealing at temperatures above the highest glass transition temperature of all blocks. For comparison reasons, the initial dendrons (miktoarm star terpolymer precursors) which are connected to each other in order to synthesize the final dendritic terpolymers are characterized in solution and in bulk and their self-assembly is also studied. A major conclusion is that specific structures are adopted which depend on the type of the core connection between the ligand and the active sites of the dendrons.

(1) Background: Natural peptides supporting the innate immune system studied at the functional and mechanistic level are a rich source of innovative compounds for application in human therapy. Increasing evidence indicates that apart from antimicrobial activity, some of them exhibit selective cytotoxicity towards tumor cells. Their cationic, amphipathic structure enables interactions with the negatively-charged membranes of microbial or malignant cells. It can be modeled in 3D by application of dendrimer chemistry. (2) Methods: Here we presented design principles, synthesis and bioactivity of branched peptides constructed from ornithine (Orn) assembled as proline (Pro)- or histidine (His)-rich dendrons and dendrimers of the bola structure. The impact of the structure and amphipathic properties of dendrons/dendrimers on two glioblastoma cell lines U87 and T98G was studied with the application of proliferation, apoptosis and cell migration assays. Cell morphology/cytoskeleton architecture was visualized by immunofluorescence microscopy. (3) Results: Dimerization of dendrons into bola dendrimers enhanced their bioactivity. Pro- and His-functionalized bola dendrimers displayed cytostatic activity, even though differences in the responsiveness of U87 and T98G cells to these compounds indicate that their bioactivity depends not only on multiple positive charge and amphipathic structure but also on cellular phenotype. (4) Conclusion: Ornithine dendrons/dendrimers represent a group of promising anti-tumor agents and the potential tools to study interrelations between drug bioactivity, its chemical properties and tumor cells&rsquo, phenotype.

The stereoisomerically pure synthesis of a novel heptanuclear Ru(II)–Os(II) antenna bearing multitopic terpyridine ligands is reported. An unambiguous structural characterization was obtained by 1H NMR spectroscopy and ion mobility spectrometry (IMS-MS). The heptanuclear complex exhibits large molar absorption coefficients (77900 M–1 cm–1 at 497 nm) and undergoes unitary, downhill, convergent energy transfer from the peripheral Ru(II) subunits to the central Os(II) that displays photoluminescence with a lifetime (τ = 161 ns) competent for diffusional excited-state electron transfer reactivity in solution.

International audience; The goal of nanomedicine is to address specific clinical problems optimally, to fight human diseases, and to find clinical relevance to change clinical practice. Nanomedicine is poised to revolutionize medicine via the development of more precise diagnostic and therapeutic tools. The field of nanomedicine encompasses numerous features and therapeutic disciplines. A plethora of nanomolecular structures have been engineered and developed for therapeutic applications based on their multitasking abilities and the wide functionalization of their core scaffolds and surface groups. Within nanoparticles used for nanomedicine, dendrimers as well polymers have demonstrated strong potential as nanocarriers, therapeutic agents, and imaging contrast agents. In this review, we present and discuss the different criteria and parameters to be addressed to prepare and develop druggable nanoparticles in general and dendrimers in particular. We also describe the major requirements, included in the preclinical and clinical roadmap, for NPs/dendrimers for the preclinical stage to commercialization. Ultimately, we raise the clinical translation of new nanomedicine issues.

International audience; Gene delivery, one important cancer-therapy mode, still remains to be challenging because of the shortage of highly efficient and safe nonviral vectors. Here, we revisit the development of cationic phosphorus dendrimers by synthesizing them with different generations (G1–3) and surface ligands (1-(2-aminoethyl) pyrrolidine, 1-(3-aminopropyl) piperidine, or 1-(2-aminoethyl) piperidine) for optimized gene delivery toward cancer-gene-therapy applications. First, the synthesized dendrimer derivatives were employed to condense plasmid DNA (pDNA) encoding enhanced green fluorescent protein (EGFP) to optimize their gene-delivery efficiency by varying the dendrimer generations and surface polycationic ligands. We show that all dendrimer/pDNA polyplexes display good cytocompatibility, and the 1-(2-aminoethyl) pyrrolidine-modified protonated G1 dendrimers (1-G1) display the best gene-delivery efficiency to HeLa cells under the same conditions through flow cytometry and fluorescence microscopic imaging analyses. Hence, 1-G1 dendrimers were then used as a vector to transfect pDNA encoding both EGFP and p53 protein for cancer-gene-therapy applications. Our results reveal that under the optimized conditions, the transfection of pDNA induces the significant p53 protein expression as verified through the resulted cell cycle arrest (regulation of p21 and Cdk4/Cyclin-D1 expression) and Western blotting. The cancer-gene-therapy potential of the polyplexes was finally validated through therapy of a xenografted tumor model after intratumoral injection without systemic toxicity. The developed cationic 1-G1 dendrimers may be adopted as a powerful vector system for gene therapy of cancer, as well as for highly effective gene therapy of other diseases.

International audience; First-in-class CuII and AuIII metaled phosphorus dendrons were synthesized and showed significant antiproliferative activity against several aggressive breast cancer cell lines. The data suggest that the cytotoxicity increases with reducing length of the alkyl chains, whereas the replacement of CuII with AuIII considerably increases the antiproliferative activity of metaled phosphorus dendrons. Very interestingly, we found that the cell death pathway is related to the nature of the metal complexed by the plain dendrons. CuII metaled dendrons showed a potent caspase-independent cell death pathway, whereas AuIII metaled dendrons displayed a caspase-dependent apoptotic pathway. The complexation of plain dendrons with AuIII increased the cellular lethality versus dendrons with CuII and promoted the translocation of Bax into the mitochondria and the release of Cytochrome C (Cyto C).

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.

Organic macromolecules with dendrimeric architectures are polymeric materials potentially useful as nanocarriers for therapeutic drugs. In this work, we evaluate a series of Newkome-type dendrons in Langmuir and Langmuir-Blodgett films as platforms capable of interacting with a potential antitumoral agent. The nanocomposite is proposed as model for the development of surface mediated drug delivery systems. We were successful in the formation and characterization of pure (dendrons) and composite (drug-dendron) stable and reproducible monolayers, and their transfer to solid substrates. A detailed study of topographic characteristics of the generated surfaces by atomic force microscopy was conducted. Furthermore, we probed dendron monolayer films as anchorage surfaces for mammalian cells. Normal cell attachment and proliferation on the surfaces were observed. No evident cytotoxic effects were detected, demonstrating the adequate biocompatibility of the surfaces. Fil: Dib, Nahir. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química y Física; Argentina Fil: Reviglio, Ana Lucía. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química y Física; Argentina Fil: Fernández, Luciana. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química y Física; Argentina Fil: Morales, Gustavo. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química y Física; Argentina Fil: Santo, Marisa Rosana. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química y Física; Argentina Fil: Otero, Luis Alberto. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química y Física; Argentina Fil: Alustiza, Fabrisio Eduardo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina Fil: Liaudat, Ana Cecilia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina Fil: Bosch, Pablo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina Fil: Calderon, Marcelo. Universität zu Berlin; Alemania. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina Fil: Martinelli, Marisa. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; Argentina Fil: Strumia, Miriam Cristina. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; Argentina

The present study outlines the important steps to bring electrochemical conversion of carbon dioxide (CO2) closer to commercial viability by using a large-scale metallic foam electrode as a highly conductive catalyst scaffold. Because of its versatility, it was possible to specifically tailor three-dimensional copper foam through coating with silver dendrite catalysts by electrodeposition. The requirements of high-yield CO2 conversion to carbon monoxide (CO) were met by tuning the deposition parameters toward a homogeneous coverage of the copper foam with nanosized dendrites, which additionally featured crystallographic surface orientations favoring CO production. The presented results evidence that Ag dendrites, owing a high density of planes with stepped (220) surface sites, paired with the superior active surface area of the copper foam can significantly foster the CO productivity. In a continuous flow-cell reactor setup, CO Faradaic efficiencies reaching from 85 to 96% for a wide range of low applied cathode potentials (, Authors acknowledge funding from Generalitat de Catalunya through the CERCA program, 2017 SGR 1246, 2017 SGR 327 and the Spanish MINECO projects MAT2014-59961, ENE2016-80788-C5-5-R and ENE2017-85087, together with the support from REPSOL S.A. ICN2 acknowledges the support from the Severo Ochoa Programme (grant no. SEV2017-0706). F.U. acknowledges the financial support from MINECO through Juan de la Cierva fellowship (FJCI-2016-29147).

International audience; Synthetic delivery systems that are described as smart are considered essential for the successful development of gene therapies. Dynamic covalent polymers (DCP) are dynamic and adaptive species that can expand and shorten their main chain in a reversible fashion. In particular, polyacylhydrazone DCPs are pH-sensitive and undergo hydrolytic dissociation at acidic pH, which is an interesting feature for gene delivery. Building upon our previous finding that cationic DCPs can complex DNA through multivalent interactions, we report here on a new generation of DCPs that incorporate modified amino acids. The covalent self-assembly through polycondensation was extended towards multifunctional DCPs combining different building blocks and different molecular dynamics. These biomolecular DCPs were found able to complex both long DNA and siRNA, and biological studies demonstrate that they are able to deliver functional siRNA in living cells. This straightforward and modular approach to the self-production of multifunctional and biomolecular DCPs as siRNA vectors can therefore constitute a stepping stone in smart gene delivery using dynamic and adaptive biodynamers.

The design of compounds with directed action to a defined organ or tissue is a very promising approach, since it can decrease considerably the toxicity of the drug/bioactive compound. For this reason, this kind of strategy has been greatly important in the scientific community. Dendrimers, on the other hand, comprise extremely organized macromolecules with many peripheral functionalities, stepwise controlled synthesis, and defined size. These nanocomposites present several biological applications, demonstrating their efficiency to act in the pharmaceutical field. Considering that, the main purpose of this review was describing the potential of dendrons and dendrimers as drug targeting, applying different targeting groups. This application has been demonstrated through interesting examples from the literature considering the last ten years of publications.

International audience; The explosive growth of nanotechnology has brought challenging innovations in the synthesis of multifunctional nano-objects able to revolutionize the field of diagnosis and therapy in medicine. Furthermore, one important input of today's nanotechnology in biology is that their design will also allow real progress to achieve temporal and spatial site local therapy and imaging. Such a breakthrough is made possible by the development of multifunctional biocompatible nanosystems resulting from cutting-edge researches based on pluridisciplinary approaches. Among the challenges are the design of the organic coating and its grafting at the surface of NPs while preserving the properties of both NPs and molecules. The molecules should ensure the colloidal stability of NPs in physiological media, their biocompatibility and biodistribution, and may bear functions to couple bioactive groups. This paper aims at providing challenges in functionalization of iron oxide nanoparticles for biomedical applications. © 2015 by De Gruyter 2015.

1700692 Fully addressable DNA nanostructures, especially DNA origami, possess huge potential to serve as inherently biocompatible and versatile molecular platforms. However, their use as delivery vehicles in therapeutics is compromised by their low stability and poor transfection rates. This study shows that DNA origami can be coated by precisely defined one-to-one protein-dendron conjugates to tackle the aforementioned issues. The dendron part of the conjugate serves as a cationic binding domain that attaches to the negatively charged DNA origami surface via electrostatic interactions. The protein is attached to dendron through cysteine-maleimide bond, making the modular approach highly versatile. This work demonstrates the coating using two different proteins: bovine serum albumin (BSA) and class II hydrophobin (HFBI). The results reveal that BSA-coating significantly improves the origami stability against endonucleases (DNase I) and enhances the transfection into human embryonic kidney (HEK293) cells. Importantly,it is observed that BSA-coating attenuates the activation of immune response in mouse primary splenocytes. Serum albumin is the most abundant protein in the blood with a long circulation half-life and has already found clinically approved applications in drug delivery. It is therefore envisioned that the proposed system can open up further opportunities to tune the properties of DNA nanostructures in biological environment, and enable their use in various delivery applications.

The immense scope of variation in dendritic molecules (hyper-branching, nano-sized, hydrophobicity/hydrophilicity, rigidity/flexibility balance, etc.) and their versatile functionalization, with the possibility of multivalent binding, permit the design of highly improved, novel materials. Dendritic-based materials are therefore viable alternatives to conventional polymers. The overall aim of this work is to show the advantages of dendronization processes by presenting the synthesis and characterization of three different dendronized systems: (I) microbeads of functionalized chitosan; (II) nanostructuration of polypropylene surfaces; and (III) smart dendritic nanogels. The particular properties yielded by these systems could only be achieved thanks to the dendronization process. Fil: Martinelli, Marisa. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Strumia, Miriam Cristina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina

In the last few decades, the synthesis of nanodevices has become a very active research field with many applications in biochemistry, biotechnology, and biomedicine. However, there is still a great need for smart nanomaterials that can sense and respond to environmental changes. Temperature- and pH-responsive nanogels (NGs), which are prepared in a one-pot synthesis from N-isopropylacrylamide (NiPAm) and a Newkome-type dendron (ABC) bearing carboxylic acid groups, are being investigated as multi-responsive drug carriers. As a result, NGs have been developed that are able to undergo a reversible volume phase transition triggered by acidic conditions, like the ones found in endolysosomal compartments of cancer cells. The NGs have been thoroughly characterized using dynamic light scattering and spectroscopies, such as infrared, nuclear magnetic resonance, UV-visible, and stimulated Raman. Strong hydrogen bonds have been detected when the ABC moieties are deprotonated, which has led to changes in the transition temperatures of the NGs and a reversible, pH-dependent aggregation. This pH-dependent phase change was exploited for the effective encapsulation and sustained release of the anticancer drug cisplatin and resulted in a faster release of the drug at endolysosomal pH values. The cisplatin-loaded NGs have exhibited high toxicities against A549 cells in vitro, while the unloaded NGs have been found to be not cytotoxic and hemocompatible. Fil: Rimondino, Guido Noé. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Miceli, E.. Freie Universität Berlin; Alemania Fil: Molina, M.. Freie Universität Berlin; Alemania Fil: Wedepohl, S.. Freie Universität Berlin; Alemania Fil: Thierbach, S.. Freie Universität Berlin; Alemania Fil: Rühl, E.. Freie Universität Berlin; Alemania Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Martinelli, Marisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Calderón, M.. Freie Universität Berlin; Alemania

With increasing emphasis on environmental care 7 and use of renewable resources, simple and effective dendroniza- 8 tion processes were performed to obtain chitosan derivatives. We 9 present different alternatives for the modification of chitosan: 10 dendronization with a biocompatible dendron; a quaternization 11 process with an ammonium salt, which confers a permanent 12 positive charge to the polymer; and a combination of method- 13 ologies allowing amphiphilic polymers. This process confers 14 unique multivalent properties to the native chitosan, and further 15 modifications reach multivalent water-soluble polymers. Hence, 16 the most important highlight of this work is the use of renewable 17 natural polymers and the different methodologies applied to nontoxic solvents with low temperatures. The process described in 18 this paper represents a sustainable alternative for obtaining a functionalized material with properties suitable for application in 19 different areas, such as biomedicine or environmental remediation. Fil: Rimondino, Guido Noé. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Strumia, Miriam Cristina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Martinelli, Marisa. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The synthesis of new dendrons of the generations 0, 1 and 2 with a double bond at the focal point and a carbonyl group at the termini has been carried out. The carbonyl group has been exploited for the multivalent conjugation to a sample saccharide by reductive amination and alkoxyamine conjugation. © 2014 Bini et al; licensee Beilstein-Institut.

The pyridine ring–introduced phenylazomethine dendrimer (PyDPA) was synthesized by a dehydration reaction using titanium(IV) chloride. The ultraviolet–visible absorption and the electrochemical study showed that the introduction of the pyridine ring produces a smaller band gap by increasing the highest occupied molecular orbital level and decreasing the lowest unoccupied molecular orbital level. A crystal of a PyDPA-PdCl2 complex was also prepared. Traditional phenylazomethine dendrimers cannot form a complex with palladium, indicating that PyDPA can potentially coordinate with various metal salts such as Co, Ni, Ru, and Mn and can be used for catalytic or electronic applications.

The ground state absorption spectra, spectra and lifetimes of the luminescence originating from the lowest S1 (Q(0,0)) and higher S2 (B) excited states of porphyrin core in the dendrimers with ether-linked carbazole dendrons have been studied in detail. The relationship between the molecular design of the dendritic shell and the optical features of the dendrimer core in solution is presented. The influence of the axial ligation of the porphyrin core and the conformational flexibility of the dendritic shell on the luminescent properties of the studied dendrimers is revealed.

Pd-catalyzed Sonogashira cross-coupling reactions were used to synthesize novel π-conjugated oligothienylene-ethynylene dendrons and their corresponding terpyridine-based ligands. Their complexation with Ru(II) led to interesting novel metallodendrimers with rich spectroscopic properties. All new compounds were fully characterized by 1H and 13C NMR, as well as MALDI–TOF mass spectra. Density functional theory (DFT) calculations performed on these complexes gave more insight into the molecular orbital distributions. Photophysical and electrochemical studies were carried out in order to elucidate structure–property relationships and the effect of the dendritic structure on the metal complexes. Photophysical studies of the complexes revealed broad absorption spectra covering from 250 to 600 nm and high molar extinction coefficients. The MLCT emission of these complexes were significantly red-shifted (up to 115 nm) compared to the parent [Ru(tpy)2]2+ complex.

Efficient DNA delivery into cells is the prerequisite of the genetic manipulation of organisms in molecular and cellular biology as well as, ultimately, in nonviral gene therapy. Current reagents, however, are relatively inefficient, and structure-activity relationships to guide their improvement are hard to come by. We now explore peptide dendrimers as a new type of transfection reagent and provide a quantitative framework for their evaluation. A collection of dendrimers with cationic and hydrophobic amino acid motifs (such as KK, KA, KH, KL, and LL) distributed across three dendrimer generations was synthesized by a solid-phase protocol that provides ready access to dendrimers in milligram quantities. In conjunction with a lipid component (DOTMA/DOPE), the best reagent, G1,2,3-KL ((LysLeu)8(LysLysLeu)4(LysLysLeu)2LysGlySerCys-NH2), improves transfection by 6-10-fold over commercial reagents under their respective optimal conditions. Emerging structure-activity relationships show that dendrimers with cationic and hydrophobic residues distributed in each generation are transfecting most efficiently. The trigenerational dendritic structure has an advantage over a linear analogue worth up to an order of magnitude. The success of placing the decisive cationic charge patterns in inner shells rather than previously on the surface of macromolecules suggests that this class of dendrimers significantly differs from existing transfection reagents. In the future, this platform may be tuned further and coupled to cell-targeting moieties to enhance transfection and cell specificity.

Novel poly(aryl ether) dendron-based low-molecular-weight organogelaters (LMWG) containing naphthalene units at the core have been synthesized, and the self-Assembly of the system has been examined in a variety of solvents and solvent mixtures. The compounds readily form gels with attractive critical gel concentration values associated with gelation-induced enhanced emission (GIEE). In addition to the remarkable properties of the previously reported anthracene and pyrene analogues (Rajamalli, P.; Prasad, E. Org. Lett.2011, 13, 3714 and Rajamalli, P.; Prasad, E. Soft Matter2012, 8, 8896), the self-Assembled systems exhibit distinctly different structure-property relationships. Unlike the reported ones, the present system forms sheetlike morphology in nonpolar solvent mixtures, giant vesicles in polar solvent mixtures, and lamellar or hexagonal columnar phases in single solvents. The unique properties of the self-Assembled systems, which were analyzed through electron microscopic (SEM, TEM, AFM) and spectroscopic techniques (POM, fluorescence), are attributed to the replacement of anthracene/pyrene units by naphthalene units. The present work unravels the subtle role of minute structural change in altering the properties of LMWGs based on poly(aryl ether) dendrons. � 2013 American Chemical Society.

In order to improve the efficiency of the anti-inflammatory drug ibuprofen, cationic carbosilanedendrimers and dendrons with ibuprofen at their periphery or at their focal point, respectively, havebeen synthesized and the release of the drug was studied using HPLC. Macrophages were used toevaluate the anti-inflammatory effect of the ibuprofen-conjugated dendritic systems and comparedwith mixtures of non-ibuprofen dendritic systems in the presence of the drug. The cationic ibuprofenconjugateddendron was the compound that showed higher anti-inflammatory properties. It reduces the LPS-induced COX-2 expression, decreases the release of several inflammatory cytokines such as TNFalfa, IL-1beta, IL-6 and CCL3. These results open new perspectives in the use of these compounds asdrug carriers., Ministerio de Economía y Empresa

Hydrogels have emerged as a versatile class of polymeric materials with a wide range of applications in biomedical sciences. The judicious choice of hydrogel precursors allows one to introduce the necessary attributes to these materials that dictate their performance towards intended applications. Traditionally, hydrogels were fabricated using either polymerization of monomers or through crosslinking of polymers. In recent years, dendrimers and dendrons have been employed as well-defined building blocks in these materials. The multivalent and multifunctional nature of dendritic constructs offers advantages in either formulation or the physical and chemical properties of the obtained hydrogels. This review highlights various approaches utilized for the fabrication of hydrogels using well-defined dendrimers, dendrons and their polymeric conjugates. Examples from recent literature are chosen to illustrate the wide variety of hydrogels that have been designed using dendrimer- and dendron-based building blocks for applications, such as sensing, drug delivery and tissue engineering.

Here, we introduced a new technology based on the incorporation of dendrons-branched chemical structures-onto supports for synthesis of HIC adsorbents. In doing so we studied the synthesis and performance of these novel HIC dendron-based adsorbents. The adsorbents were synthesized in a facile two-step reaction. First, Sepharose 4FF (R) was chemically modified with polyester dendrons of different branching degrees i.e. third (G3) or fifth (G5) generations. Then, butyl-end valeric acid ligands were coupled to dendrons via ester bond formation. UV-vis spectrophotometry and FTIR analyses of the modified resins confirmed the presence of the dendrons and their ligands on them. Inclusion of dendrons allowed the increment of ligand density, 82.5 ± 11 and 175.6 ± 5.7 μmol ligand/mL resin for RG3 and RG5, respectively. Static adsorption capacity of modified resins was found to be ~60 mg BSA/mL resin. Interestingly, dynamic binding capacity was higher at high flow rates, 62.5 ± 0.8 and 58.0 ± 0.5 mg/mL for RG3 and RG5, respectively. RG3 was able to separate lipase, β-lactoglobulin and α-chymotrypsin selectively as well as fractionating of a whole proteome from yeast. This innovative technology will improve the existing HIC resin synthesis methods. It will also allow the reduction of the amount of adsorbent used in a chromatographic procedure and thus permit the use of smaller columns resulting in faster processes. Furthermore, this method could potentially be considered as a green technology since both, dendrons and ligands, are formed by ester bonds that are more biodegradable allowing the disposal of used resin waste in a more ecofriendly manner when compared to other exiting resins., Biotechnology and Synthetic Biology Focus Group (002EICIP01--0020DII001); Chemistry and Nanotechnology Department (0020CDB088); National Council on Science and Technology of Mexico (CONACyT) (242286--204152); EU-FP7-Marie Curie Action (PIRSES-GA 2010-269211)

Three generations of pyrenyl bis-MPA dendrimers with two different end-groups, acetonide (pyrGn) or alcohol (pyrGn-OH) (n = 1–3), were synthesized, and the pyrenyl group of the dendritic molecules was encapsulated in the arene ruthenium metallacages, [Ru6(p-cymene) 6 (OO∩OO)3(tpt)2]6+ (OO∩OO = 5,8-dioxydo- 1,4-naphtaquinonato (donq) [1]6+ and 6,11-dioxydo-5,12- naphtacenedionato (dotq) [2]6+; tpt =2,4,6-tri(pyridin-4-yl)-1,3,5-triazine). The host–guest properties of [guestC1]6+ and [guestC2]6+ were studied in solution by NMR and UV–vis spectroscopic methods, thus allowing the determination of the affinity constants. Moreover, the cytotoxicity of these water- soluble host–guest systems and the pyrenyl-dendrimers was evaluated on human ovarian cancer cells.

Two new water soluble dendronized polymers (PLn) from acrylate Behera amine monomer of different molecular weights were successfully synthesized. The polymers were characterized by FTIR, NMR, GPC and DLS. Both GPC and DLS results indicated that these PLn have a remarkable tendency to form aggregates in solution that lead to apparent molecular weights that are much higher than their theoretical values, as well as large diameters in solution. However, the addition of any PLn to water did not cause any increase in viscosity up to concentrations of 1000 ppm. The possible interactions of PLn with the cationic surfactant CTAT were explored by solution rheometry. A synergistic viscosity enhancement was found by adding small amounts of dendronized PLn polymers to a CTAT solution composed of entangled wormlike micelles. The highest association tendency with CTAT was found for PL1 at the maximum polymer concentration before phase separation (i.e., 100 ppm). The solution viscosity at low shear rates could be increased by an order of magnitude upon addition of 100 ppm of PL1 to a 20 mM CTAT solution. For this mixture, the fluid obtained was highly structured and exhibited only shear thinning behavior from the smallest shear rates employed. These PL1/CTAT mixtures exhibited an improved elastic character (as determined by dynamic rheometry) that translated in a much longer value of the cross-over relaxation time and a pronounced thixotropic behavior which are indicative of a strong intermolecular interaction. In the case of the polymer with a higher theoretical molecular weight, PL2, its association with CTAT leads to an extraordinary doubling of solution viscosity with just 0.25 ppm polymer addition to a 20 mM CTAT solution. However, such synergistic viscosity enhancement saturated at rather low concentrations (25 ppm) indicating an apparent lower solubility as compared to PL1, a fact that may be related to its higher molecular weight. Fil: Cuggino, Julio César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina. Universidad Nacional de Cordoba. Facultad de Ciencias Quimicas; Argentina Fil: Calderon, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Freie Universität Berlin; Alemania Fil: Alvarez Igarzabal, Cecilia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Cordoba. Facultad de Ciencias Quimicas; Argentina Fil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Cordoba. Facultad de Ciencias Quimicas; Argentina Fil: Silva, Karolaine. Universidad Simón Bolívar; Venezuela Fil: Penott Chang, Evis. Universidad Simón Bolívar; Venezuela Fil: Müller, Alejandro. Universidad Simón Bolívar; Venezuela

We report on the solid-state structural features of self-assembled chiral supramolecules based on ionic complexation of chiral cholesteric pendant groups with achiral dendritic macromolecules and show that their optical activity exhibits a systematic change in the ultraviolet/visible light (UV-vis) absorption and enhancement in the circular dichroism (CD) signal, indicating the occurrence of supramolecular chirality, also referred to as induced circular dichroism (ICD). We construct a homologous series of complexes by varying systematically from 1 to 3 the generation of dendritic units contained in dendrons, dendrimers, and dendronized polymers. The structural properties of the complexes are investigated by means of small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Depending on the class of dendritic molecule and the generation, lamellar, columnar hexagonal, oblique columnar, and rectangular columnar phases can be found, with a direct correlation among the degrees of freedom of the dendritic macromolecules used and the level of order achieved in the self-assembled solid-state structures. The enhancement of the optical signals of these mesoscopic structures appears to be correlated with their order in the solid state. Complexes with the longest lattice correlation lengths also show the most enhanced CD signals. These results show the unique versatility of dendritic macromolecules as supramolecular templates capable of organizing low molecular weight chiral pendant units into a variety of solid-state structures with amplified optical properties.

Biosensors such as DNA microarrays and microchips are gaining an increasing importance in medicinal, forensic, and environmental analyses. Such devices are based on the detection of supramolecular interactions called hybridizations that occur between complementary oligonucleotides, one linked to a solid surface (the probe), and the other one to be analyzed (the target). This paper focuses on the improvements that hyperbranched and perfectly defined nanomolecules called dendrimers can provide to this methodology. Two main uses of dendrimers for such purpose have been described up to now; either the dendrimer is used as linker between the solid surface and the probe oligonucleotide, or the dendrimer is used as a multilabeled entity linked to the target oligonucleotide. In the first case the dendrimer generally induces a higher loading of probes and an easier hybridization, due to moving away the solid phase. In the second case the high number of localized labels (generally fluorescent) induces an increased sensitivity, allowing the detection of small quantities of biological entities.

We describe the design, synthesis, and "stimuli-responsive" study of ferrocene-linked Fr�chet-type [poly(aryl ether)]-dendron-based organometallic gels, in which the ferrocene moiety is attached to the dendron framework through an acyl hydrazone linkage. The low-molecular-weight gelators (LMWGs) form robust gels in both polar and non-polar solvent/solvent mixtures. The organometallic gels undergo stimuli-responsive behavior through 1) thermal, 2) chemical, and 3) electrochemical methods. Among them, conditions 1 and 3 lead to seamlessly reversible with repeated cycles of identical efficiency. Results indicate that the flexible nature of the poly(aryl ether) dendron framework plays a key role in retaining the reversible electrochemical behavior of ferrocene moiety in the LMWGs. Further, the organometallic gelators have exhibited unique selectivity towards Pb2+ ions (detection limit ?10-8 M). The metal ion-sensing results in a gel-sol phase transition associated with a color change visible to the naked eye. Most importantly, decomplexing the metal ion from the system leads to the regeneration of the initial gel morphology, indicating the restoring ability of the organometallic gel. The metal-ligand binding nature has been analyzed by using 1H NMR spectroscopy, mass spectrometry, and DFT calculations. Receptive dendritic gelators: Ferrocene-containing poly(aryl ether) dendron based low-molecular-weight organometallic gels exhibit multi-stimuli-responsive behavior under thermal, chemical, and electrochemical conditions, and in also presence of Pb2+ ions. Results suggest the reversible thermal and redox switching of the gel, in addition to its ability to sense Pb2+ ions with restorable tendency (see figure). � 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dendrons constituted of an adamantane core, a focal point and three arms, were synthetized starting from a multifunctional adamantane derivative. Maleimido groups at the periphery of the scaffold were used to covalently attach the peptide called P140, a therapeutic phosphopeptide controlling disease activity in systemic lupus, both in mice and patients. Biotinylation of the trimers at the focal point was performed using click chemistry and the conjugates were studied in terms of solubility, binding affinity to its receptor, the HSPA8/HSC70 chaperone protein, effect on HSPA8 folding property and in vivo activity. The results showed that the trimerization of P140 peptide does not trigger aggregation or steric hindrances during the interaction with HSPA8 protein. Compared to the monomeric cognate peptide, the trivalent P140 peptide displayed the same capacity, in vitro, to down-regulate HSPA8 activity and, in vivo in MRL/lpr lupus-prone mice, to reduce abnormal blood hypercellularity. The control trimer synthesized with the same scaffold and a scrambled sequence of P140 showed no effect in vivo. This work reveals that adamantane-based scaffolds with a well-defined spatial conformation are promising trivalent systems for molecular recognition and for biomedical applications. journal article research support, non-u.s. gov't 2014 Aug 2014 06 02 imported

International audience

Well-defined hybrids of linear poly(ethylene glycol)s (PEGs) and dendritic polyesters were prepared via the dendronization of the alcohol end groups of the mono and difunctional linear PEGs. Though useful for rudimentary product characterization, GPC and NMR could not verify the overall structural purity of these linear-dendritic hybrids. On the other hand, the detailed data provided by MALDI-ToF mass spectrometry enabled confirmation of the high structural purity of the dendronized PEGs at each step of the dendronization procedure. The well-defined number of functionalities on these dendronized PEGs, renders them particularly useful for research in the biomedical sphere where functionality and purity are of the utmost importance. The MALDI-ToF mass spectrometric approach described herein represents a valuable technique for detailed monitoring of these dendronization reactions, as well as a variety of other polymer end group modifications. Híbridos bem definidos de poli(etilenoglicol) lineares (PEGs) e poliésteres dendriméricos foram preparados via "dendronização" de álcool e grupos de PEGs lineares mono e bifuncionais. Embora úteis para a caracterização rudimentar de produtos, Cromatografia por Permeação em Gel e RMN podem não demonstrar a pureza estrutural global desses híbridos lineares dendríticos. Por outro lado, informações detalhadas provenientes de espectrometria de massas MALDI-ToF permitiram a confirmação de elevada pureza estrutural de PEGs "dendronizados" em cada passo do processo de "dendronização". O número de funcionalidades bem definidas destes PEGs "dendronizados", torna-os particularmente úteis para pesquisa na área biomédica, na qual funcionalidade e pureza são de grande importância. A abordagem de espectrometria de massas MALDI-ToF descrita aqui representa uma técnica valiosa para o monitoramento detalhado destas reações de "dendronização", bem como diversas modificações de outros polímeros e grupos.

The FT-Raman spectra of the zero and first generations of phosphorus-containing dendrons with terminal oxybenzaldehyde and P Cl groups and one ester function have been recorded and analyzed. The structural optimization and normal mode analysis were performed for dendrons on the basis of the density functional theory (DFT). The calculated geometrical parameters, harmonic vibrational frequencies and Raman scattering activities are predicted in a good agreement with the experimental data. The experimental Raman spectra of dendrons were interpreted by means of potential energy distribution. Relying on DFT calculations the lines of the core, repeating units and terminal groups of dendrons were assigned. The influence of the encirclement on the line frequencies and intensities was studied and due to the predictable, controlled and reproducible structure of dendrons the information, usually inaccessible is obtained. The polarizabilities and lipophilicity of dendrons were estimated. The strong line at 1600 cm−1 show marked changes of intensity in dependence of aldehyde ( СН О), ester ( OС O ) or azomethyne ( СН N ) substituents in the aromatic ring.

The design, synthesis and study of morphology as well as photophysical properties of novel low molecular weight gels (LMWG) based on non-amphiphilic pyrene cored poly(aryl ether) dendron derivatives are described. Solvent controlled self-assembly in the system results in nano-sized vesicles, which further aggregate to micro-sized vesicles and finally turned to entangled fibrillar type arrangement in the gel phase. The morphology transformations were investigated by dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and confocal laser scanning microscopy (LSCM) experiments. The nano-/micro-sized vesicles and fibre aggregates exhibit an intense light emitting property from the pyrene moiety, which is attached to the dendron through an acylhydrazone spacer group. More interestingly, the luminescence properties were found to be controlled by the solvent polarity, in a rather unusual manner, due to the selective formation of pyrene 'excimer' and 'exciplex' in solvent controlled aggregates. Furthermore, the system has been utilized to detect fluoride ions through a reversible gel-sol transition, which is associated with a color change from yellow to red. � 2012 The Royal Society of Chemistry.

International audience; The design of symmetric or asymmetric diversely functionalized monomer, dimer, or trimer viologens and the design of phosphorus building blocks allows the synthesis of unique types of mix phosphorus–viologen dendrimers. Strategies for the preparation of dendrimers of generations 0 and 1 are presented as are those for various dendrons. These methods exhibit broad applicability, high efficiency and usability, and are compatible with the presence of various functional groups (aldehyde, cyano, phenol, phosphonate, brominated groups)

The first step in the synthesis of functionalized polyamides consisted in the introduction of alkyne side groups in several types of linear polyamides by interfacial step-growth polymerization of hexane-1,6-diamine or 4,9-dioxadodecane-1,12-diamine in combination with on one hand adipoyl or sebacoyl chloride and on the other hand an alkyne-containing building block, i.e. 2-methyl-2-propargylmalonic acid dichloride. Both homo- and copolyamides were synthesized, creating a large range of alkyne-containing polyamides with degrees of functionalization ranging between 5% and 100%. Subsequently, these polyamide chains have been modified with two types of linking chemistries, respectively with azides through the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition or with thiols through the thiol-yne addition reaction.

This edge article reports the multiscale modelling of spermine-functionalised dendrons designed to bind DNA and deliver it into cells. The modelling provides an insight into the mode of self-assembly of the dendrons, in particular aggregate charge density and shape, and hence suggests explanations for some of the unexpected experimental observations. In particular, the self-assembly model helps explain why the first generation dendron is more effective in binding DNA than the second generation analogue, even though the second generation system has a greater number of surface spermine ligands. Effective self assembly of the first generation dendron leads to a high charge density assembled structure – more effective than the larger number of ligands on the second generation dendron – i.e., less is more. The modelling also suggests an alternative shape of self-assembly for the system with two hydrophobic cholesterol units (rather than one) at the dendron focal point – this may help explain why this system shows much enhanced gene delivery in vitro.