Water solubilization of hydrophobic nanocrystals by means of poly(maleic anhydride-alt-1-octadecene)
ABSTRACT 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.
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ABSTRACT: Nanoparticles can be combined with nucleic acids to programme the formation of three-dimensional colloidal crystals where the particles' size, shape, composition and position can be independently controlled. However, the diversity of the types of material that can be used is limited by the lack of a general method for preparing the basic DNA-functionalized building blocks needed to bond nanoparticles of different chemical compositions into lattices in a controllable manner. Here we show that by coating nanoparticles protected with aliphatic ligands with an azide-bearing amphiphilic polymer, followed by the coupling of DNA to the polymer using strain-promoted azide-alkyne cycloaddition (also known as copper-free azide-alkyne click chemistry), nanoparticles bearing a high-density shell of nucleic acids can be created regardless of nanoparticle composition. This method provides a route to a virtually endless class of programmable atom equivalents for DNA-based colloidal crystallization.Nature Material 05/2013; · 35.75 Impact Factor
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ABSTRACT: Sensing and imaging with fluorescent, plasmonic, and magnetic colloidal nano- and microparticles have improved during the past decade. In this review, we describe the concepts and applications of how these techniques can be used in the multiplexed mode, that is, sensing of several analytes in parallel or imaging of several labels in parallel. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 6 is June 15, 2013. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.Annual Review of Analytical Chemistry (2008) 02/2013; · 8.60 Impact Factor
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ABSTRACT: The long term fate of nanomaterials in biological environment represents a critical matter, which determines environmental effects and potential risks for human health. Predicting these risks requires understanding of nanoparticle transformations, persistence and degradation, some issues somehow ignored so far. Safe by design, inorganic nanostructures are being envisioned for therapy, yet fundamental principles of their processing in biological systems, change in physical properties and in situ degradability have not been thoroughly assessed. Here we report the longitudinal visualization of iron oxide nanocube transformations inflicted by intracellular-like environment. Structural degradation of individual nanocubes with two different surface coatings (amphiphilic polymer shell and polyethylene-glycol ligand molecules) was monitored at the atomic scale with aberration-corrected high-resolution transmission electron microscopy. Our results suggest that the polymer coating controls surface reactivity and that availability and access of chelating agents to the crystal surface govern the degradation rate. This in situ study of single nanocube degradation was compared to intracellular transformations observed in mice over fourteen days after intravenous injection, revealing the role of nanoparticle clustering, intracellular sorting within degradation compartments and iron transfer and recycling into ferritin storage proteins. Our approach reduces the gap between in situ nanoscale observations in mimicking biological environments and in vivo real tracking of nanoparticle fate.ACS Nano 05/2013; · 12.03 Impact Factor