Blue shift of CdSe/ZnS nanocrystal-labels upon DNA-hybridization

Luminescence color multiplexing is one of the most intriguing benefits, which might occur by using semiconductor Quantum Dots (QDs) as labels for biomolecules. It was found, that the luminescence of QDs can be quenched, and replaced by a luminescence peak at approximately 460 nm on hybridization with certain regions of Arabidopsis thaliana tissue. This effect is site selective, and it is unclear whether it occurs due to an energy transfer process, or due to quenching and scattering of the excitation light. The article describes methods for phase-transfer of differently coloured, hydrophobically ligated QDs, coupling of DNA strands to the QD's surface, and hybridization of the labelled DNA to different cell types of Arabidopsis thaliana. The reason for the luminescence blue-shift was studied systematically, and narrowed down to the above mentioned causes

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

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Functional one, two, and three-dimensional ZnO structures by solvothermal processing

Crystalline zinc oxide (ZnO) has been fabricated by solvothermal techniques under quite different temperature and pressure environment stretching from sub- to supercritical conditions. Among them, one-step processing of inorganic–inorganic hybrid ZnO structures based on ZnO substrate with attached ZnO nanocrystals has been challenged. Combination of doping ions was made to yield ZnO structures with luminescent properties of high potential for application in fast-decay devices. The room temperature decay of antimony, lithium (Sb, Li) codoped homoepitaxial films is reported

Both pictures are showing non-agglomerated QDs with a diameter of around 3 nm

Samples were prepared by immersion and subsequent drying of carbon-film covered copper grinds in aqueous dispersions of sample A and B.<p><b>Copyright information:</b></p><p>Taken from "Blue shift of CdSe/ZnS nanocrystal-labels upon DNA-hybridization"</p><p>http://www.jnanobiotechnology.com/content/6/1/7</p><p>Journal of Nanobiotechnology 2008;6():7-7.</p><p>Published online 19 May 2008</p><p>PMCID:PMC2405788.</p><p></p

The tissue was hybridized with five different QD-oligonucleotides of distinguishable emission wavelength

The emission of QD-labels was shifted to the strong blue. This shift appears only after hybridization. Unreacted, agglomerated QD-oligonucleotides show their initial emission behavior (red area on the right border of the picture). B) Spectral analysis of picture A. The wavelength of all hybridized QD-oligonucleotides was shifted to 460 nm. The emission of some non hybridized QD-oligonucleotides could be found at 598 nm.<p><b>Copyright information:</b></p><p>Taken from "Blue shift of CdSe/ZnS nanocrystal-labels upon DNA-hybridization"</p><p>http://www.jnanobiotechnology.com/content/6/1/7</p><p>Journal of Nanobiotechnology 2008;6():7-7.</p><p>Published online 19 May 2008</p><p>PMCID:PMC2405788.</p><p></p

Surface TOPO is replaced with MPA followed by the partial replacement of the MPA with thionylated oligonucleotides

B) Luminescence spectra of TOPO-QDs (solid line) and their corresponding oligonucleotide derivatives respectively (dashed line). Original emission-wavelength is slightly shifted to the red by TOPO replacement. C) TEM-picture of QD-oligonucleotide derivatives. There are no agglomerates observed after surface modification.<p><b>Copyright information:</b></p><p>Taken from "Blue shift of CdSe/ZnS nanocrystal-labels upon DNA-hybridization"</p><p>http://www.jnanobiotechnology.com/content/6/1/7</p><p>Journal of Nanobiotechnology 2008;6():7-7.</p><p>Published online 19 May 2008</p><p>PMCID:PMC2405788.</p><p></p