Limits of the Inversion Phenomenon in Triazolyl-Substituted β-Cyclodextrin Dimers

Asymmetric Cyclodextrin-Dimer-Involved Nanoassemblies by Selective Host-Guest Interactions: Concentration-Dependent Morphology Evolution and Light-Regulated Biomedical Applications

Supramolecular assembly has attracted significant attention and has been applied to various applications. Herein, a β-γ-CD dimer was synthesized to complex different guest molecules, including single-strand polyethylene glycol (PEG)-modified C60 (PEG-C60), photothermal conversion reagent (IR780), and dexamethasone (Dexa), according to the complexation constant-dependent specific selectivity. Spherical or cylindrical nanoparticles, monolayer or bilayer vesicles, and bilayer fusion vesicles were discovered in succession if the concentration of PEG-C60 was varied. Moreover, if near-infrared light was employed to irradiate these nanoassemblies, the thermo-induced morphological evolution, subsequent cargo release, photothermal effect, and singlet oxygen (1O2) generation were successfully achieved. The in vitro cell experiments confirmed that these nanoparticles possessed excellent biocompatibility in a normal environment and achieved superior cytotoxicity by light regulation. Such proposed strategies for the construction of multilevel structures with different morphologies can open a new window to obtain various host-guest functional materials and achieve further use for disease treatment.

Exploring the Influence of Spacers in EDTA-β-Cyclodextrin Dendrimers: Physicochemical Properties and In Vitro Biological Behavior

The synthesis of a new family of ethylenediaminetetraacetic acid (EDTA) core dimers and G0 dendrimers end-capped with two and four β-cyclodextrin (βCD) moieties was performed by click-chemistry conjugation, varying the spacers attached to the core. The structure analyses were achieved in DMSO-d6 and the self-inclusion process was studied in D2O by 1H-NMR spectroscopy for all platforms. It was demonstrated that the interaction with adamantane carboxylic acid (AdCOOH) results in a guest-induced shift of the self-inclusion effect, demonstrating the full host ability of the βCD units in these new platforms without any influence of the spacer. The results of the quantitative size and water solubility measurements demonstrated the equivalence between the novel EDTA-βCD platforms and the classical PAMAM-βCD dendrimer. Finally, we determined the toxicity for all EDTA-βCD platforms in four different cell lines: two human breast cancer cells (MCF-7 and MDA-MB-231), human cervical adenocarcinoma cancer cells (HeLa), and human lung adenocarcinoma cells (SK-LU-1). The new EDTA-βCD carriers did not present any cytotoxicity in the tested cell lines, which showed that these new classes of platforms are promising candidates for drug delivery.

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

A series of β-cyclodextrin dimers selectively permethylated on the primary or secondary rim with two different types of spacers have been synthesized effectively utilizing conventional and newly developed methods. Their structure analyses by 1H NMR and NOESY NMR imply the dependence of molecular symmetry on the type of spacer. The ability of synthesized dimers to increase the solubility of tetracene in DMSO was evaluated and compared to native cyclodextrins and their methylated derivatives. The newly synthesized compounds expressed better effectiveness than other tested supramolecular hosts.

Guest-Mediated Reversal of the Tumbling Process in Phosphorus-Dendritic Compounds Containing β-Cyclodextrin Units: An NMR Study

The conformational study of dendritic platforms containing multiple β-cyclodextrin (βCD) units in the periphery is relevant to determine the availability of βCD cavities for the formation of inclusion complexes in aqueous biological systems. In this work, we performed a detailed conformational analysis in D2O, via 1D and 2D NMR spectroscopy of a novel class of phosphorus dendritic compounds of the type P3N3-[O-C6H4-O-(CH2)n-βCD]6 (where n = 3 or 4). We unambiguously demonstrated that a functionalized glucopyranose unit of at least one βCD unit undergoes a 360° tumbling process, resulting in a deep inclusion of the spacer that binds the cyclodextrin to the phosphorus core inside the cavity, consequently limiting the availability of the inner cavities. In addition, we confirmed through NMR titrations that this tumbling phenomenon can be reversed for all βCD host units using a high-affinity guest, namely 1-adamantanecarboxylic acid (AdCOOH). Our findings have demonstrated that it is possible to create a wide variety of multi-functional dendritic platforms.

Self-Inclusion and Dissociation of a Bridging β-Cyclodextrin Triplet

To understand the self-inclusion and the dissociation in a branched β-cyclodextrin (CD) system, we designed and synthesized a β-CD trimer in which each CD group is connected to one of bridging arms of a planar triphenylbenzene core through a CuAAC click reaction. Only one rather than two or all of the three host CDs was demonstrated to be in a self-including state in water, while no self-inclusion was observed to occur in dimethylsulfoxide (DMSO) via the characterization of ¹H and NOESY NMR spectra. The configuration structures of the CD groups in the self-included state were evaluated, and the dissociation to free state in water was investigated under various conditions like heating, increased acidity, and discharging versus the addition of competitive guests. While raised temperature and increased acidity did not break the self-inclusion, two adamantane guest molecules were found to show capability in driving the equilibrium to get back to free state against the self-inclusion. The inclusion process of the added guests was believed to involve in the dissociation of the self-inclusion and the occupation of the guests in CD cavity. The results of host-guest interaction study indicated that the stable combination of guests was favorable for blocking the structural overturning of glucose toward trapping the bridging group into the cavity.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

New water-soluble Schiff base ligands based on β-cyclodextrin for aqueous biphasic hydroformylation reaction

The synthesis of water-soluble rhodium(I) salicylaldiminato and salicylhydrazonic complexes has been achieved employing two preparative routes. Schiff base condensation between 6A-deoxy-6A-amino-β-CD or 6A-deoxy-6A-hydrazino-β-CD and 5-sodiosulfonato-2-hydroxybenzaldehyde (sulfonated salicylaldehyde) (1) or 5-sodiosulfonato-3-tert-butyl-2-hydroxybenzaldehyde (sulfonated t Bu-salicylaldehyde) (2) led to the formation of the corresponding imine or hydrazone ligands (3, 4, 5 and 6). Reaction of [Rh(COD)2 +BF4 −] with these new ligands in an alkaline solution formed the corresponding rhodium complexes quantitatively. These rhodium(I) complexes could also be prepared in one-pot by mixing, in stoichiometric proportions, the modified β-CDs with the sulfonated salicylaldehyde and with the rhodium precursor in an alkaline solution at room temperature. These rhodium complexes were applied as catalysts in the aqueous biphasic hydroformylation of 1-decene as a model reaction.

Water-soluble phosphane-substituted cyclodextrin as an effective bifunctional additive in hydroformylation of higher olefins

Cyclodextrins substituted with a sulfophenyl phosphane show an excellent recognition ability towards higher olefins in aqueous biphasic Rh-catalyzed hydroformylation.

Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS

A novel β-cyclodextrin (β-CD) dimer was synthesized and surface-grafted by click chemistry onto azide-functionalized quartz surfaces in order to introduce the cooperative features of the β-CD dimer to solid surfaces. Using NMR and fluorescence spectroscopy, it is shown that the free β-CD dimer forms a 1:1 complex with the fluorescent guest molecule, 2-anilinonaphthalene-6-sulfonic acid (otherwise known not to form 1:2 complexes with parent β-CD), with an apparent association constant of 7300 M⁻¹. Further, it is shown using total internal reflection fluorescence spectroscopy that the inclusion of the fluorescent guest into both cavities of the β-CD dimer is maintained when grafted onto a solid surface.

Cyclodextrin-adamantane conjugates, self-inclusion and aggregation versus supramolecular polymer formation

β-Cyclodextrin conjugated to adamantane forms self-inclusion complexes instead of supramolecular polymers.