Glycodendrimers

Röckendorf, Niels; Lindhorst, Thisbe K.

doi:10.1007/3-540-45003-3_6

Cited by 127 publications

(54 citation statements)

References 107 publications

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“…They are Abstract: The EPTPA 5À chelate, which ensures fast water exchange in Gd III complexes, has been coupled to three different generations (5,7, and 9) of polyamidoamine (PAMAM) dendrimers through benzylthiourea linkages (H 5 EPTPA = ethylenepropylenetriamine-N,N,N',N'',N''-pentaacetic acid). The proton relaxivities measured at pH 7.4 for the dendrimer complexes G5-(GdEPTPA) 111 , G7-(GdEPTPA) 253 and G9-(GdEPTPA) 1157 decrease with increasing temperature, indicating that, for the first time for dendrimers, slow water exchange does not limit relaxivity.…”

Section: Introductionmentioning

confidence: 99%

“…[1] The potential of dendrimers in this area covers a large spectrum and involves drug delivery (transfection agents for DNA delivery into cells, glycocarriers) [2][3][4][5] antiviral treatment (naphtyl-sulfonate-loaded dendrimers show anti-HIV activity), [6] antibacterial drugs (dendrimers derivatised with tertiary alkyl ammonium groups are potent antibacterial biocides against Grampositive and negative bacteria) [7,8] or antitumor activity (photosensitisers coupled to dendrimers). [9] The diversity of possible biomedical applications results from the fact that the core, the interior and the surface functionalities of a dendrimer can be all tuned to a desired objective.…”

Section: Introductionmentioning

confidence: 99%

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Rotational Dynamics Account for pH‐Dependent Relaxivities of PAMAM Dendrimeric, Gd‐Based Potential MRI Contrast Agents

Laus¹,

Sour²,

Ruloff³

et al. 2005

Chemistry A European J

115

118

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The EPTPA5) chelate, which ensures fast water exchange in GdIII complexes, has been coupled to three different generations (5, 7, and 9) of polyamidoamine (PAMAM) dendrimers through benzylthiourea linkages (H5EPTPA = ethylenepropylenetriamine-N,N,N',N'',N''-pentaacetic acid). The proton relaxivities measured at pH 7.4 for the dendrimer complexes G5-(GdEPTPA)111, G7-(GdEPTPA)253 and G9-(GdEPTPA)1157 decrease with increasing temperature, indicating that, for the first time for dendrimers, slow water exchange does not limit relaxivity. At a given field and temperature, the relaxivity increases from G5 to G7, and then slightly decreases for G9 (r1 = 20.5, 28.3 and 27.9 mM(-1) s(-1), respectively, at 37 degrees C, 30 MHz). The relaxivities show a strong and reversible pH dependency for all three dendrimer complexes. This originates from the pH-dependent rotational dynamics of the dendrimer skeleton, which was evidenced by a combined variable-temperature and multiple-field 17O NMR and 1H relaxivity study performed at pH 6.0 and 9.9 on G5-(GdEPTPA)111. The longitudinal 17O and 1H relaxation rates of the dendrimeric complex are strongly pH-dependent, whereas they are not for the [Gd(EPTPA)(H2O)]2- monomer chelate. The longitudinal 17O and 1H relaxation rates have been analysed by the Lipari-Szabo spectral density functions and correlation times have been calculated for the global motion of the entire macromolecule (tau(gO)) and the local motion of the GdIII chelates on the surface (tau(lO)), correlated by means of an order parameter S2. The dendrimer complex G5-(GdEPTPA)111 has a considerably higher tau(gO) under acidic than under basic conditions (tau(298)gO = 4040 ps and 2950 ps, respectively), while local motions are less influenced by pH (tau(298)lO = 150 and 125 ps). The order parameter, characterizing the rigidity of the macromolecule, is also higher at pH 6.0 than at pH 9.9 (S2 = 0.43 vs 0.36, respectively). The pH dependence of the global correlation time can be related to the protonation of the tertiary amine groups in the PAMAM skeleton, which leads to an expanded and more rigid dendrimeric structure at lower pH. The increase of tau(gO) with decreasing pH is responsible for the pH dependent proton relaxivities. The water exchange rate on G5-(GdEPTPA)111(k(298)ex = 150 x 10(6) s(-1)) shows no significant pH dependency and is similar to the one measured for the monomer [Gd(EPTPA)(H2O)]2-. The proton relaxivity of G5-(GdEPTPA)111 is mainly limited by the important flexibility of the dendrimer structure, and to a small extent, by a faster than optimal water exchange rate.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rotational Dynamics Account for pH‐Dependent Relaxivities of PAMAM Dendrimeric, Gd‐Based Potential MRI Contrast Agents

Laus¹,

Sour²,

Ruloff³

et al. 2005

Chemistry A European J

115

118

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“…Several different classes of glycodendrimers harboring α-D-mannopyranoside residues have been synthesized in the past from our groups (Figure 14) and from others (Röckendorf, Lindhorst, 2001;Hartmann, Lindhorst, 2011), including calyx[4]arenes , fullerene , and cyclodextrins (Martínez, Mellet, Garcia Fernández, 2013). Figure 14 illustrates typical cases wherein L-lysine (Nagahori et al, 2002) was used as scaffold (33, 37, 38), together with "Majoral-type" cyclotriphosphazene (34) (Touaibia, Roy, 2008), and aromatic scaffolds that included hexaphenylbenzene (35) (Chabre et al, 2011) and hexamethylthiobenzene (36) .…”

Section: Glycodendrimers As Bacterial Anti-adhesinsmentioning

confidence: 99%

Glycodendrimers: versatile tools for nanotechnology

Roy

Shiao

Rittenhouse-Olson

2013

Braz. J. Pharm. Sci.

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Combining nanotechnology with glycobiology has triggered an exponential growth of research activities in the design of novel functional bionanomaterials (glyconanotechnology). More specifically, recent synthetic advances towards the tailored and versatile design of glycosylated nanoparticles namely glyconanoparticles, considered as synthetic mimetics of natural glycoconjugates, paved the way toward diverse biomedical applications. The accessibility of a wide variety of these structured nanosystems, in terms of shapes, sizes, and organized around stable nanoparticles have readily contributed to their development and applications in nanomedicine. In this context, glycosylated gold-nanoparticles (GNPs), glycosylated quantum dots (QDs), fullerenes, single-wall natotubes (SWNTs), and self-assembled glycononanoparticles using amphiphilic glycopolymers or glycodendrimers have received considerable attention to afford powerful imaging, therapeutic, and biodiagnostic devices. This review will provide an overview of the most recent syntheses and applications of glycodendrimers in glycoscience that have permitted to deepen our understanding of multivalent carbohydrate-protein interactions. Together with synthetic breast cancer vaccines, inhibitors of bacterial adhesions to host tissues including sensitive detection devices, these novel bionanomaterials are finding extensive relevance.

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“…The coordinated binding of multiple ligands on one chemical entity to multiple receptors on another is typically defined as a multivalent interaction and it can be much stronger than the sum of the corresponding monovalent interactions [216][217][218][219][220][221][222][223][224][225]. The relative ease of increasing binding affinities by multiplying the number of existing interactions [226][227][228][229], rather than addressing the more complicated task of evolving a new and stronger interaction could be an efficient way forward in the design of more effective receptors, drug delivery agents, inhibitors, and catalysts [230][231][232][233][234][235].…”

Section: Multivalency and Interlocked Moleculesmentioning

confidence: 99%