Dendrimer nanoparticles

Optical properties of dendrimers bearing eight chromophores have been examined by single molecule spectroscopy techniques. It is especially exciting that variations in the spectra are recorded if one of these dendrimers is observed for a period of time under continuous irradiation.1481 The fluorescence intensity of the dendrimer nanoparticle also jumps between discrete emissive levels. All these findings suggest the existence of strong electronic interactions between several perylene imide chromophores within one dendrimer and provide new... 

In this chapter we introduce structures and physicochemical properties of dendrimers. Then synthesis and characterization of dendrimer-nanoparticles are discussed. 

Supramolecular Complexes, Molecular Engineering, Dendrimers, Nanoparticles... 

Alexander Florence is Dean of The School of Pharmacy at the University of London he was previously James P. Todd Professor of Pharmaceutics at the University of Strathclyde. His research and teaching interests are drug delivery and targeting, dendrimers, nanoparticles, non-aqueous emulsions, novel solvents for use in pharmacy and general physical pharmaceutics. He co-authored the book Surfactant Systems their Chemistry, Pharmacy and Biology with David Attwood. 

With time and improved synthetic protocols, larger templates (fuUerenes, dendrimers, nanoparticles, colloids, micelles, lipid bilayers, self-assembled block copolymers, oligonucleotides, DNA and proteins) have been imprinted [14] and the choice of matrices has expanded to liquid crystal polysiloxanes, carbon networks, zeolites, layered aluminophosphates and colloidal crystals, though organic polymer networks remain the dominant imprint casting medium [14]. 

Thus, particles with a very narrow distribution were observed - in the case of a second generation dendrimer, nanoparticles with a monodisperse nucleus of 2.4 0.2 nm. It is important that not only individual dendrimers can be used for metallopolymer preparation, but also their dispersed mixtures with polymer matrices, which form new types of polymer-inorganic nanomaterials. For example, the highest poly(amidoamide) generations in water were put in swollen polymeric patterns of poly(2-hydroxyethylmethacrylate) Cu, Au or ions of a complex bound to dendrimer [90] were added to such a composition. Reduction of the metal ions resulted in new types of inorganic hybrid materials. 

Surface functionalization of dendrimer nanoparticles with suitable ligands, size, surface groups, and surface charge plays a key role on the cellular internalization by endocytosis, phagocytosis, miCTopinocytosis, or fluid-phase endocytosis. 

Oliveira, JM., Sousa, RA., Kotobuki, N. et al. 2009b. The osteogenic differentiation of rat bone marrow stromal cells cultured with dexamethasone-loaded carboxymethyl chitosan + polyamidoamine dendrimer nanoparticles. Biomaterials 30 804—813. 

Keywords Luminophores Organic systems Inorganic systems Dendrimers Nanoparticle systems Nanoclusters Carbon nanoparticles Semiconductor nanocrystals Quantum dots... 

Figure 10.6 (a) Schematic representation of the encapsulation and lysozyme release mechanism from carboxymethyl chitosan-grafted-poly(amidoamine) (CM-chitosan-PAMAM)/ lysozyme polyion complex (PIC) nanoparticles, (b) Schematic representation of synthesis and self-assembling for CM-chitosan-PAMAM dendrimer nanoparticles, and the encapsulation and lysozyme release mechanism from CM-chitosan-PAMAM/lysozyme PIC nanoparticles. Reprinted from X. Zhang, J. Zhao, Y. Wen, C. Zhu.J. Yang, F. Yao, Carboxymethyl chitosan-poly(amidoamme) dendrimer core-shell nanoparticles for intracellular lysozyme dehvery, Carhohydrate Polymers 98 (2013) 1326-1334. Copyright (2013), with permission from Elsevier. 

S. Deng, J. Locklin, D. Patton, A. Baba and R. C. Advincula, Thiophene dendron jacketed poly(amidoamine) dendrimers nanoparticle synthesis and adsorption on graphite, J. Am. Chem. Soc., 127, 1744-1751 (2005). 

Narain R (ed) (2011) Engineered carbohydrate-based materials for biomedical applications-Polymers, surfaces, dendrimers, nanoparticles, and hydrogels. Wiley, Hoboken... 

From the points of view of composition and structure, composite nanoparticles can be thought of as a class existing in between two classes that are being heavily researched internationally "soft" dendrimer nanoparticles and "hard" nanocrystalline gold particles. "Soft" dendrimer nanoparticles are heavily studied, as witnessed by more than 7,000 papers and patents, hundreds of books and reviews. "Hard" nanoparticles are most acknowledged because of their catalytic activity. Potential... 

In a study conducted by Liu et at, a doxorubicin (Dox)-carrier system was developed by electrostatic complexion of G4 PAMAM dendrimer with a pH-sensitive diblock copolymer of poly(methacryloyl sulfadimethoxine) (PSD) and PEG, with lactose (LA) coupled at the distal end of the PEG chain [77]. A higher cumulative Dox release from LA-PEG-b-PSD/PAMAM complexes was observed at pH 6.5 compared to pH 7. In another study, a pH-sensitive dendrimer nanoparticle was prepared, where surface cationic charge of the PAMAM dendrimer was reduced to prevent opsonization in the systemic circulation [78]. Zwitterionic chitosan (ZWC), a chitosan derivative with a unique pH-sensitive charge profile, was used to modify the cationic surface of PAMAM dendrimers. A stable electrostatic complex between ZWC and PAMAM was formed at pH 7.4, where the PAMAM dendrimer surface was covered with ZWC. The results demonstrated that ZWC can mask the surface charge, which minimizes hemolytic and cytotoxic activities of PAMAM dendrimers. However, the complex dissociated due to the charge conversion at low pH, allowing PAMAM dendrimer charge to be exposed and facilitate its entrance into the cells. 

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