Amount Of QDs Research Articles

Effect of Cell Age on Uptake and Toxicity of Nanoparticles: The Overlooked Factor at the Nanobio Interface.

Clinical translation of nanotechnologies has limited success, at least in part, due to the existence of several overlooked factors on the nature of the nanosystem (e.g., physicochemical properties of nanoparticles), nanobio interfaces (e.g., protein corona composition), and the cellular characteristics (e.g., cell type). In the past decade, several ignored factors including personalized and disease-specific protein corona (a layer of formed biomolecules at the surface of nanoparticles upon their entrance into a biological fluid), incubating temperature, local temperature gradient, cell shape, and cell sex has been introduced. Here, it was hypothesized and validated cell age as another overlooked factor in the field of nanomedicine. To test our hypothesis, cellular toxicity and uptake profiles of our model nanoparticles (i.e., PEGylated quantum dots, QDs) were probed in young and senescent cells (i.e., IMR90 fibroblast cells from human fetal lung and CCD841CoN epithelial cells from human fetal colon) and the outcomes revealed substantial dependency of cell-nanoparticles interactions to the cell age. For example, it was observed that the PEGylated QDs were acutely toxic to senescent IMR90 and CCD841CoN cells, leading to lysosomal membrane permeabilization which caused cell necrosis; in contrast, the young cells were resilient to the exact same amount of QDs and the same incubation time. It was also found that the formation of protein corona could delay the QDs' toxicity on senescent cells. These findings suggest that the cellular aging process have a capacity to cause deteriorative effects on their organelles and normal functions. The outcomes of this study suggest the proof-of-concept that cell age may have critical role in biosystem responses to nanoparticle technologies. Therefore, the effect of cell age should be carefully considered on the nanobio interactions and the information about cellular age (e.g., passage number and age of the cell donor) should be included in the nanomedicine papers to facilitate clinical translation of nanotechnologies and to help scientists to better design and produce safe and efficient diagnostic/therapeutic age-specific nanoparticles.

Broadband optical transparency in plasmonic nanocomposite polymer films via exciton-plasmon energy transfer.

Inherent absorptive losses affect the performance of all plasmonic devices, limiting their fascinating applications in the visible range. Here, we report on the enhanced optical transparency obtained as a result of the broadband mitigation of optical losses in nanocomposite polymeric films, embedding core-shell quantum dots (CdSe@ZnS QDs) and gold nanoparticles (Au-NPs). Exciton-plasmon coupling enables non-radiative energy transfer processes from QDs to metal NPs, resulting in gain induced transparency of the hybrid flexible systems. Experimental evidences, such as fluorescence quenching and modifications of fluorescence lifetimes confirm the presence of this strong coupling between plexcitonic elements. Measures performed by means of an ultra-fast broadband pump-probe setup demonstrate loss compensation of gold NPs dispersed in plastic network in presence of gain. Furthermore, we compare two films containing different concentrations of gold NPs and same amount of QDs, to investigate the role of acceptor concentration (Au-NPs) in order to promote an effective and efficient energy transfer mechanism. Gain induced transparency in bulk systems represents a promising path towards the realization of loss compensated plasmonic devices.

Effect of transition metal ion doping on the photocatalytic activity of ZnS quantum dots: Synthesis, characterization, and application for dye decolorization

In this research, green and aqueous based synthesis routes were performed for chemical preparation of pure and transition metal ions doped ZnS quantum dots at room temperature. Doping of ZnS QDs by three transition metal ions (Mn2+, Co2+, Ni2+ ions) as dopants have been investigated by various techniques. In the optical absorption studies, a broad absorption band in the wavelength range of 280–300nm clearly reveals quantum size effect in ZnS QDs. The crystal structure and the approximate size of QDs were measured by XRD pattern. The average particle size of QDs was found to be around 1–3nm. In addition, the photocatalytic activities of the prepared ZnS QDs as their abilities to remove methyl violet (MV) cationic dye, as a model molecule, were studied. Effect of the experimental parameters, such as the type of dopant and the amount of QDs, pH of the initial dye solution, irradiation time, ionic strength of reaction media, and initial dye concentration on the decolorization efficiency (DE) of QDs as green nano-semiconductors were studied. The results demonstrated that doped QDS (for 5% of dopants) effectively bleached out MV, showing positive photocatalytic enhancement over pure ZnS nanoparticles.

18F- and 11C-labelling of quantum dots with n.c.a. [18F]fluoroethyltosylate and [11C]methyliodide: a feasibility study

Quantum dots functionalized on the outer surface with either amino- or carboxyl functions were labelled with [18F]fluoroethyltosylate and [11C]methyliodide in order to use the positron emitter-labelled fluorescence agents for multimodality imaging techniques, i.e. fluorescence imaging and positron emission tomography. 18F-Labelling of both compounds was realized with yields up to 5% as determined by size exclusion chromatography, which is twice as much as reported in literature before [1]. 11C-Labelling of amino- and carboxyl-QDs proceeded with good yields (up to 45 and 35%, respectively) under optimized reaction conditions. In general for both QD-types and both labelling agents the labelling yield increased with the amount of QDs used in the reaction as well as with reaction time and reaction temperature.