Water-Soluble Pegylated Quantum Dots:  From a Composite Hexagonal Phase to Isolated Micelles

Abstract

We present a simple method based on the dispersion of fluorescent quantum dots (QD) into a liquid crystal phase that provides either nanostructured material or isolated QD micelles depending on water concentration. The liquid-crystal phase was obtained by using a gallate amphiphile with a poly(ethylene glycol) chain as the polar headgroup, named I. The hydration of QD/I mixtures resulted in the formation of a composite hexagonal phase identified by small-angle X-ray scattering and by polarized light and fluorescence optical microscopy, showing a homogeneous distribution of fluorescence within hexagonal phase. This composite mesophase can be converted into isolated QD-I micelles by dilution in water. The fluorescent QD-I micelles, purified by size exclusion chromatography, are well monodisperse with a hydrodynamic diameter of 20-30 nm. Moreover, these QD do not show any nonspecific adsorption on lipid or cell membranes. By simply adjusting the water content, the PEG gallate amphiphile I provides a simple method to prepare a self-organized composite phase or pegylated water soluble QD micelles for biological applications.

Synthesis, Radiolabelling and In Vitro Imaging of Multifunctional Nanoceramics

“…Dynamic light scattering (DLS) showed that dispersions in chloroform Cd 0.1 Zn 0.9 Se and of Fe 3 O 4 , Fe 3 O 4 /Cd 0.1 Zn 0.9 Se@SiO 2 ( C ) NPs in water had size distributions centered at 25, 45 and 300 nm respectively (Figure S23, ESI). Although the DLS suggests a small amount of aggregation in solution, it is known that this technique yields higher diameters than those observed by TEM ,,. TEM and HRTEM demonstrate that the NPs have a core‐shell structure with a dark contrast metal core and a light contrast silica shell.…”

Biocompatible Polymer/Quantum Dots Hybrid Materials: Current Status and Future Developments

“…In a typical example, extensive works have demonstrated that amphiphilic PEG polymers can well encapsulate QDs as the hydrophobic core and stabilize QDs in water [40,41,42,43]. The resulted biocompatible PEG/QDs have been shown to have the potential to detect and image biomolecules.…”

Gold nanoparticles and quantum dots for bioimaging

“…Surface‐modified QDs with PEG are biocompatible both with living cells in culture (Ryman‐Rasmussen et al,2007) and whole animals. PEG polymer is an attractive corona‐forming candidate for micelles and QDs due to their physical, chemical, and biological properties as well as the availability of the material (Ballou et al,2007; Bentzen et al,2005; Boulmedais et al,2006; Yu et al,2006). Reports on the distribution and pharmacokinetic properties (Gao et al,2004; Kim et al,2004; So et al,2006) of cadmium selenide QDs show that these nanoparticles are sequestered in several organs after intravenous administration, but of particular note, they accumulate in lymph nodes (Frangioni et al,2007) and solid tumors (Ballou et al,2007).…”