Degradable dendrimer‐like PEOs were designed using an original ABC‐type branching agent featuring a cleavable ketal group, following an iterative divergent approach based on the anionic ring opening polymerization (AROP) of ethylene oxide and arborization of PEO chain ends. A seventh generation dendrimer‐like PEO carrying 192 peripheral hydroxyls and exhibiting a molar mass of 446 kg · mol−1 was obtained in this way. The chemical degradation of these dendritic scaffolds was next successfully accomplished under acidic conditions, forming linear PEO chains of low molar mass (≈2 kg · mol−1), as monitored by 1H NMR, SEC, and MALDI‐TOF mass spectrometry as well as by AFM.
The chemistry of dendrimers is a fast developing field and has brought about a tsunami of research activity since Vogtle reported the first preparation in 1978. These hyperbranched macromolecules have grown out of chemists' imagination and have challenged synthetic chemists with their architectural complexity and intriguity. The potentials of these macromolecules are extensive and are synthesized using both organic and inorganic cores from which different scaffoldings are built, and upon which functionalities are attached for specific applications. The synthesis and characterizations of cisplatin and rhenium(Ⅰ) containing PAMAM derivatives will be discussed. 相似文献
In this study we extend our previous work in the self-organization of dendrimer polyelectrolytes (Macromolecules, 2008 , 41, 225) by examining the effects of dendrimer concentration and/or total volume fraction in the ordering process and the resulting structure, in the arrangement of counterions and dendrimer beads and in the diffusive motion of dendrimers at different strengths of Coulombic interactions. It is found that as long as the total volume fraction remains low (i.e. no jamming phenomena intervene) the symmetry of the resulted cubic phases is unaltered. At a higher volume fraction and at the strong electrostatic regime a kinetic arrest of the dendrimer molecules much in analogy to a colloidal glass-like transition is observed, inhibiting thus the ordering process. Changes in the strength of electrostatic interactions and dendrimer concentration induces a systematic variation of the counterion - counterion and the counterion - charged-dendrimer-bead spatial arrangement. These findings are in qualitative agreement with previous studies in systems with very different structural details of the considered solutes, indicating a more general behaviour in charged macroion/counterion solutions. 相似文献
An approach based on a dendrimer display of B- and T-cell epitopes relevant for antibody induction has been shown to be effective as a foot-and-mouth disease (FMD) vaccine. B2T dendrimers combining two copies of the major FMD virus (FMDV) type O B-cell epitope (capsid proteinVP1 (140–158)) covalently linked to a heterotypic T-cell epitope from non-structural protein 3A (21–35), henceforth B2T-3A, has previously been shown to elicit high neutralizing antibody (nAb) titers and IFN-γ-producing cells in both mice and pigs. Here, we provide evidence that the B- and T-cell epitopes need to be tethered to a single molecular platform for successful T-cell help, leading to efficient nAb induction in mice. In addition, mice immunized with a non-covalent mixture of B2T-3A dendrimers containing the B-cell epitopes of FMDV types O and C induced similarly high nAb levels against both serotypes, opening the way for a multivalent vaccine platform against a variety of serologically different FMDVs. These findings are relevant for the design of vaccine strategies based on B- and T-cell epitope combinations. 相似文献
Dendronized cellulose derivatives are discussed. Regarding our own studies, novel bulky esters of cellulose were synthesized homogeneously in N,N- dimethyl acetamide/LiCl or dimethyl sulfoxide in combination with fluoride ions by conversion of the biopolymer with 3,5-dihydroxybenzoic acid based aryl polyester dendrons. The carboxylic acid moieties were efficiently activated in situ with N,N′-carbonyldiimidazole or the acid chloride was applied. Cellulose esters with values of the degree of substitution of up to 0.7 were obtained. The functionalization analyzed by NMR spectroscopy occurs not only at position 6 (primary hydroxyl group) but also the secondary one at position 2. 相似文献