Water solubilization of hydrophobic nanocrystals by means of poly(maleic anhydride-alt-1-octadecene)
Poly(maleic anhydride-alt-1-octadecene), a cheap and commercially available polymer, was used to water-solubilize colloidal nanocrystals with various compositions, morphologies, and sizes. Highly pure nanoparticles with homogeneous distributions of sizes and surface charges were obtained after a single purification step of the polymer-coated particles by ultracentrifugation, saving precious time as compared to a previously published and similar polymer coating procedure. This simple strategy proved also to be generally applicable and represents a valid methodology to water-solubilize nanoparticles.
Available from: Ralph Alexander Sperling
- "The phase transfer of hydrophobic nanoparticles of a variety of different core materials has been demonstrated by Pellegrino et al. (2004), using commercial poly(maleic anhydride alt-1-tetradecene), which is no longer available. The still available analogue poly(maleic anhydride alt-1-octadecene) can be used with an adopted procedure (Di Corato et al. 2008). A similar commercial derivative with tertiary amino groups has also been used for nanoparticle coating and phase transfer (Qi & Gao 2008), saving the step of postmodification with dimethylethylenediamine and EDC (Yezhelyev et al. 2008). "
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ABSTRACT: Inorganic colloidal nanoparticles are very small, nanoscale objects with inorganic cores that are dispersed in a solvent. Depending on the material they consist of, nanoparticles can possess a number of different properties such as high electron density and strong optical absorption (e.g. metal particles, in particular Au), photoluminescence in the form of fluorescence (semiconductor quantum dots, e.g. CdSe or CdTe) or phosphorescence (doped oxide materials, e.g. Y(2)O(3)), or magnetic moment (e.g. iron oxide or cobalt nanoparticles). Prerequisite for every possible application is the proper surface functionalization of such nanoparticles, which determines their interaction with the environment. These interactions ultimately affect the colloidal stability of the particles, and may yield to a controlled assembly or to the delivery of nanoparticles to a target, e.g. by appropriate functional molecules on the particle surface. This work aims to review different strategies of surface modification and functionalization of inorganic colloidal nanoparticles with a special focus on the material systems gold and semiconductor nanoparticles, such as CdSe/ZnS. However, the discussed strategies are often of general nature and apply in the same way to nanoparticles of other materials.
Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 03/2010; 368(1915):1333-83. DOI:10.1098/rsta.2009.0273 · 2.15 Impact Factor
Available from: Maria Ada Malvindi
- "Because of the variety of well established or new published nanocrystal synthesis, solubilization and functionalization protocols, which found our group deeply involved – and the diverse experimental systems (cell lines, tissue or animals) used to test them, not general rules exist to predict the interaction between nanocrystals and the targeted cell membrane and the effect of long-term exposure. Evidences are cumulating that nanoparticles play active roles even in the absence of specific ligands and that factors such as size and charge are crucial for activation of cell responses , internalization , , and intracellular trafficking –. "
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ABSTRACT: Initially viewed as innovative carriers for biomedical applications, with unique photophysical properties and great versatility to be decorated at their surface with suitable molecules, nanoparticles can also play active roles in mediating biological effects, suggesting the need to deeply investigate the mechanisms underlying cell-nanoparticle interaction and to identify the molecular players. Here we show that the cell uptake of fluorescent CdSe/CdS quantum rods (QRs) by Hydra vulgaris, a simple model organism at the base of metazoan evolution, can be tuned by modifying nanoparticle surface charge. At acidic pH, amino-PEG coated QRs, showing positive surface charge, are actively internalized by tentacle and body ectodermal cells, while negatively charged nanoparticles are not uptaken. In order to identify the molecular factors underlying QR uptake at acidic pH, we provide functional evidence of annexins involvement and explain the QR uptake as the combined result of QR positive charge and annexin membrane insertion. Moreover, tracking QR labelled cells during development and regeneration allowed us to uncover novel intercellular trafficking and cell dynamics underlying the remarkable plasticity of this ancient organism.
PLoS ONE 11/2009; 4(11):e7698. DOI:10.1371/journal.pone.0007698 · 3.23 Impact Factor
Available from: Yutaka Ohya
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ABSTRACT: Transparent colloidal aqueous solutions of anatase nanocrystals were hydrothermally synthesized from aqueous transparent sols
with tetramethylammonium titanate colloids, the surfaces of which were modified with citric acid, by structural conversion
of the titanate to anatase. This modification hindered coalescence of the titanate colloids during the hydrothermal synthesis.
Although the amount of citric acid adsorbed on the colloids was reduced during hydrothermal treatment, a small amount of citric
acid was adsorbed on the resulting anatase nanocrystals. Moreover, the use of the titanate colloids as a precursor was compared
with the use of a citrato Ti complex, tetramethylammonium citratotitanate. The hydrothermal treatment of the transparent aqueous
solutions of the Ti complex yielded opaque solutions with large anatase colloids, suggesting that the titanate colloids were
useful for preparing transparent anatase colloidal solutions. Because the shape and size of resulting colloids may be dependent
on the size and shape of starting colloids, the use of titanate colloids as a precursor may make it easy to control size and
shape of anatase colloids.
KeywordsAnatase–Hydrothermal synthesis–Nanocrystal–Titanate–Water-dispersible colloid
Journal of Nanoparticle Research 01/2010; 13(1):273-281. DOI:10.1007/s11051-010-0027-y · 2.18 Impact Factor
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