Biomimetic, Mild Chemical Synthesis of CdTe-GSH Quantum Dots with Improved Biocompatibility

Multiple applications of nanotechnology, especially those involving highly fluorescent nanoparticles (NPs) or quantum dots (QDs) have stimulated the research to develop simple, rapid and environmentally friendly protocols for synthesizing NPs exhibiting novel properties and increased biocompatibility

Uptake and intracellular localization of CdTe-GSH QDs by MKN45 cells.

<p><b>A,</b> Confocal fluorescence images of MKN45 cells incubated with 100 µg/ml CdTe-GSH QDs in the absence (100 QD) or presence of lipofectamine (100 QD+L). QDs are shown in green and cell cytoplasm was stained by phalloidin (red). <b>B,</b> MKN45 cells incubated with 100 µg/ml CdTe-GSH QDs plus lipofectamine (100 QD+L). QDs are shown in green and cell nuclei were stained by PI (red).</p

Characterization of QDs incorporation into MKN45 cells by flow cytometry.

<p><b>A,</b> Per cent of cells incorporating QDs. <b>B,</b> MFI represent the amount of QDs incorporated after incubation with 25, 50 and 100 µg/ml QDs in the presence of lipofectamine. <b>C,</b> Viability of MKN45 cells incubated with QDs with or without lipofectamine. The total population of cells (QD⁺PI⁻, QD⁺PI⁺ and QD⁻PI⁺) is referred to as 100%. Numbers indicate concentrations (µg/ml) and L stands for lipofectamine. <b>D,</b> Characterization of cell death in MKN45 cells incubated with QDs plus lipofectamine. 100% stands for the total population of QD⁺ cells.</p

IR spectra of CdTe-GSH NPs and GSH.

<p>IR spectra of CdTe-GSH NPs and GSH.</p

Absorbance and fluorescence emission spectra of CdTe-GSH QDs synthesized at 90°C.

<p><b>A,</b> samples were withdrawn at the indicated times. <b>B,</b> fluorescence of the as-produced CdTe-GSH QDs at the indicated times of synthesis and excited with UV light at 312 nm. <b>C,</b> Dynamic Light Scattering (DLS) analysis of green, yellow and red CdTe-GSH nanoparticles.</p

Absorbance and fluorescence emission spectra of CdTe-GSH QDs synthesized at different pHs at 90°C.

<p><b>A,</b> above, CdTe-GSH QDs after 2 h; below, same CdTe-GSH QDs after 4 h. Samples prepared at pH 13 showed no fluorescence at 4 h. <b>B,</b> Effect of nucleation temperature on CdTe-GSH absorbance peaks measured at different times of synthesis.</p

Sex-specific evolution of bite performance in **Liolaemus** lizards (Iguania: Liolaemidae): the battle of the sexes

Although differential selective pressures on males and females of the same species may result in sex-specific evolutionary trajectories, comparative studies of adaptive radiations have largely neglected within-species varia-tion. In this study, we explore the potential effects of natural selection, sexual selection, or a combination of both, on bite performance in males and females of 19 species of Liolaemus lizards. More specifically, we study the evolution of bite performance, and compare evolutionary relationships between the variation in head morphology, bite performance, ecological variation and sexual dimorphism between males and females. Our results suggest that in male Liolaemus, the variation in bite force is at least partly explained by the variation in the degree of sexual dimorphism in head width (i.e. our estimate of the intensity of sexual selection), and neither bite force nor the morphological variables were correlated with diet (i.e. our proxy for natural selection). On the contrary, in females, the variation in bite force and head size can, to a certain extent, be explained by variation in diet. These results suggest that whereas in males, sexual selection seems to be operating on bite performance, in the case of females, natural selection seems to be the most likely and most important selective pressure driving the variation in head size. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 461–475. ADDITIONAL KEYWORDS: diet – ecomorphology – interspecific variation – natural selection – sexual differences – sexual selection