Search results for "Dendrimer"
showing 10 items of 131 documents
Amphiphilic Dendrimers Control Protein Binding and Corona Formation on Liposome Nanocarriers
2020
Amphiphilic polyphenylene dendrimers (PPDs) with distinct lipophilic and positively or negatively charged surface groups were adsorbed onto liposomes and their impact on protein adsorption in blood plasma was studied. The PPD corona reduced binding of specific opsonins and increased the adsorption of proteins controlling cellular uptake based on their surface patches.
Preparation and Characterization of Novel Poly(alkylidenamine) Nitrile Ruthenium Metallodendrimers
2010
Complete functionalization of N,N,N',N'-[tetrakis(cyanoethyl)-hexamethylenediamine] [N≡C(CH 2 ) 2 ] 2 N(CH 2 ) 6 N[(CH 2 ) 2 -C≡N] 2 (4) and N,N,N',N'-(tetrakis(cyanoethoxypropyl)hexamethylenediamine] [N≡C(CH 2 ) 2 O(CH 2 ) 3 ] 2 N(CH 2 ) 6 N[(CH 2 ) 3 -O(CH 2 ) 2 C≡N] 2 (7) with the organometallic moiety [Ru(η 5 -C 5 H 5 )(PPh 3 ) 2 Cl] and the five-coordinate cis-[RuCl(dppe) 2 ]-[PF 6 ] [dppe = 1,2-bis(diphenylphosphanyl)ethane] was attained with good yield, respectively, by treating the metallo-fragment with the core in methanol (at room temperature and in presence of TIPF 6 as a chloride abstractor) and in 1,2-dichloroethane (under reflux). These novel nitrile-functionalized poly(alkyli…
A Polyphenylene Dendrimer Drug Transporter with Precisely Positioned Amphiphilic Surface Patches
2014
The design and synthesis of a polyphenylene dendrimer (PPD 3) with discrete binding sites for lipophilic guest molecules and characteristic surface patterns is presented. Its semi-rigidity in combination with a precise positioning of hydrophilic and hydrophobic groups at the periphery yields a refined architecture with lipophilic binding pockets that accommodate defined numbers of biologically relevant guest molecules such as fatty acids or the drug doxorubicin. The size, architecture, and surface textures allow to even penetrate brain endothelial cells that are a major component of the extremely tight blood-brain barrier. In addition, low to no toxicity is observed in in vivo studies using…
The development of synthetic antitumour vaccines from mucin glycopeptide antigens.
2013
Based on important cell-biological and biochemical results concerning the structural difference between membrane glycoproteins of normal epithelial cells and epithelial tumour cells, tumour-associated glycopeptide antigens have been chemically synthesised and structurally confirmed. Glycopeptide structures of the tandem repeat sequence of mucin MUC1 of epithelial tumour cells constitute the most promising tumour-associated antigens. In order to generate a sufficient immunogenicity of these endogenous structures, usually tolerated by the immune system, these synthetic glycopeptide antigens were conjugated to immune stimulating components: in fully synthetic two-component vaccines either with…
Applications and Limitations of Dendrimers in Biomedicine
2020
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 focus…
Dendrimers as Non-Viral Vectors in Gene-Directed Enzyme Prodrug Therapy.
2021
Gene-directed enzyme prodrug therapy (GDEPT) has been intensively studied as a promising new strategy of prodrug delivery, with its main advantages being represented by an enhanced efficacy and a reduced off-target toxicity of the active drug. In recent years, numerous therapeutic systems based on GDEPT strategy have entered clinical trials. In order to deliver the desired gene at a specific site of action, this therapeutic approach uses vectors divided in two major categories, viral vectors and non-viral vectors, with the latter being represented by chemical delivery agents. There is considerable interest in the development of non-viral vectors due to their decreased immunogenicity, higher…
Internal dynamics and energy transfer in dansylated POPAM dendrimers and their eosin complexes.
2010
Internal dynamics of dansylated poly(propyleneamine) dendrimers (POPAM, G1-G4) in solution and excitation energy transfer from dansyls to eosin in POPAM-eosin complexes have been studied by time-resolved fluorescence spectroscopy and molecular dynamics (MD) simulations. Combining the results from fluorescence anisotropy and the MD simulation studies suggests three time domains for the internal dynamics of the G3 and G4 generations, about 60 ps for motions of the outer-sphere dansyls, 500-1000 ps for restricted motions of back-folded dansyls, and 1500-2600 ps for the overall rotation. For the smaller generations, the contribution from the restricted motions was not entirely evident. Eosin bi…
Hyperbranched Polyglycerols: From the Controlled Synthesis of Biocompatible Polyether Polyols to Multipurpose Applications
2009
Dendritic macromolecules with random branch-on-branch topology, termed hyperbranched polymers in the late 1980s, have a decided advantage over symmetrical dendrimers by virtue of typically being accessible in a one-step synthesis. Saving this synthetic effort once had an unfortunate consequence, though: hyperbranching polymerization used to result in a broad distribution of molecular weights (that is, very high polydispersities, often M(w)/M(n)5). By contrast, a typical dendrimer synthesis yields a single molecule (in other words, M(w)/M(n) = 1.0), albeit by a labor-intensive, multistep process. But 10 years ago, Sunder and colleagues reported the controlled synthesis of well-defined hyperb…
Hybrid Organic-Inorganic Nanostructures Fabricated from Layer-by-Layer Self-Assembled Multilayers of Hyperbranched Polyglycerols and Phosphorus Dendr…
2007
Multilayer thin films of cationic phosphorous dendrimers and anionic hyperbranched polyglycerols were fabricated by electrostatic layer-by-layer (LbL) self-assembly (SA). The film formation was monitored by surface plasmon resonance (SPR) spectroscopy and UV-visible spectroscopy, and it was found that the stepwise, alternating deposition results in a linear growth up to four bilayers. Hybrid organic-TiO2 nanostructures were generated by exposing the supramolecular multilayers to TiCl4 precursors. The amounts of TiO2 incorporated inside the scaffolds could be tuned by controlling the porosity of the multilayers with the addition of a small amount of salts. The resulting hybrid films exhibit …
A versatile methodology for the controlled synthesis of photoluminescent high-boron-content dendrimers.
2013
Fluorescent star-shaped mol- ecules and dendrimers with a 1,3,5-tri- phenylbenzene moiety as the core and 3 or 9 carborane derivatives at the pe- riphery, have been prepared in very good yields by following different ap- proaches. One procedure relies on the nucleophilic substitution of Br groups in 1,3,5-tris(4-(3-bromopropoxy)phe- nyl)benzene with the monolithium salts of methyl and phenyl-o-carborane. The second method is the hydrosilylation reactions on the peripheral allyl ether functions of 1,3,5-tris(4-allyloxy-phe- nyl)benzene and 1,3,5-tris(4-(3,4,5-tris- AAA with suitable carboranyl-silanes to produce different generations of dendrimers decorated with carboranyl fragments. This ap…