Synthesis of folic acid functionalized gold nanoclusters for targeting folate receptor-positive cells

We report on the synthesis of water-soluble gold nanoclusters capped with polyethylene glycol (PEG)-based ligands and further functionalized with folic acid for specific cellular uptake. The dihydrolipoic acid-PEG-based ligands terminated with -OMe, -NH2 and -COOH functional groups are produced and used for surface passivation of Au nanoclusters (NCs) with diameters <2 nm. The produced sub 2 nm Au NCs possess long-shelf life and are stable in physiologically relevant environments (temperature and pH), are paramagnetic and biocompatible. The paramagnetism of Au NCs in solution is also reported. The functional groups on the capping ligands are used for direct conjugation of targeting molecules onto Au NCs without the need for post synthesis modification. Folic acid (FA) is attached via an amide group and effectively target cells expressing the folate receptor. The combination of targeting ability, biocompatibility and paramagnetism in FA-functionalized Au NCs is of relevance for their exploitation in nanomedicine for targeted imaging

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Abstract. A stepwise character of cadmium telluride melting is shown by using differential thermal analysis and conductivity measurements in the 1323 to 1473 K temperature range. According to the results of differential thermal analysis the parameters of CdTe melting are determined by the premelting processes that are related to defect production in crystal lattice. The crystallization processes are controlled with the melt state (structure) that depends on its maximum temperature

The differential effect of apoferritin-PbS nanocomposites on cell cycle progression in normal and cancerous cells

We report the effects induced by near-infrared apoferritin-PbS (AFt-PbS) nanocomposites on cell cycle progression in non-tumorigenic and cancerous human cells. By using flow cytometry and Annexin V assay, we show that the cell cycle of non-tumorigenic cells is not altered by exposure to AFt-PbS nanoparticles at concentrations up to 1 mg mL -1. In contrast, exposure of human-derived breast cancer cell lines to AFt-PbS at concentrations > 0.2 mg mL -1 triggers apoptotic cell death. The selective death of cancerous cells and the near-infrared fluorescence properties of AFt-PbS could be exploited in both nanomedicine and in vivo imaging studies. © 2012 The Royal Society of Chemistry

Size Dependence of Temperature-Related Optical Properties of PbS and PbS/CdS Core/Shell Quantum Dots

The effect of PbS core size on the temperature-dependent photoluminescence (PL) of PbS/CdS quantum dots (QDs) in the temperature range of 100-300 K was thoroughly investigated and compared with shell-free PbS QDs. The core/shell QDs show significantly smaller PL intensity variation with temperature at a smaller PbS size, while a larger activation energy when the PbS domain size is relatively large, suggesting both different density and different distribution of defects/traps in the PbS and PbS/CdS QDs. The most remarkable difference consists in the PbS size dependence of the energy gap temperature coefficient (dE/dT). The PbS/CdS QDs show unusual non-monotonic dE/dT variation, resulting in the reversal of the dE/dT difference between the PbS and PbS/CdS QDs at a larger PbS size. In combination with theoretical calculations, we find that, although lattice dilation and carrier-phonon coupling are generally considered as dominant terms, the unique negative contribution to dE/dT from the core/shell interfacial strain becomes most important in the relatively larger-core PbS@CdS QDs