Behind the buzz and beyond the hype: Our daily Nanowerk-exclusive nanotechnology feature article. Some stories are more like an introduction to nanotechnology, some are about understanding current developments, and some are advanced reviews of leading edge research.
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Showing spotlights 1 - 6 of 18 in category Quantum Dots (newest first):
The usefulness of quantum dots comes from their peak emission frequency's extreme sensitivity to both the dot's size and composition. QDs have been touted as possible replacements for organic dyes in the imaging of biological systems, due to their excellent fluorescent properties, good chemical stability, broad excitation ranges and high photobleaching thresholds. In order for quantum dots to be useful as as nanoemitters for biological imaging, they need to be linked with a specific sensor molecule that exclusively targets a biomolecule of interest. These conjugations are usually made using small linker molecules although this often demands multistep procedures and may suffer from QD colloidal instabilities during the coupling reactions. Demonstrating hyaluronic acid-QD conjugates, researchers in Korea have now solved this problem by simple electrostatic conjugation which offers stable and size-tunable conjugates.... nanotechnology article
In a recent Nanowerk Spotlight we reported on a single molecule approach to directly visualize and map protein binding sites on DNA using fluorescent quantum dots. One of the challenges the researchers in this work had was to measure distances between probes bound to combed DNA with nanometer resolution. Whereas very short distance (below 10 nm) can be assessed by FRET measurements and distances above the Rayleigh criterion can be measured, say, with a standard microscopy picture and a ruler, distances in between need to be addressed differently. This is were a novel approach by scientists at UCLA fills the gap, and, as they claim, better than other techniques do.... nanotechnology article
Proteins that bind to specific sites of DNA are essential to all biological functions of DNA. These DNA-binding proteins include transcription factors which modulate the process of transcription, various polymerases, nucleases which cleave DNA molecules, and histones which are involved in chromosome packaging in the cell nucleus. Developing methods to precisely determine the locations and occupancy of DNA-binding proteins is instrumental to scientists' understanding of cellular processes like gene expression and regulation. Motivated by the desire to overcome some of the inherent limitations of existing biochemical techniques for mapping protein binding sites on DNA, scientists at UCLA have now demonstrated the viability of a single molecule approach to directly visualize and map protein binding sites on DNA using fluorescent quantum dots, allowing multicolor, nanometer-resolution localization.... nanotechnology article
The properties of a quantum dot are not only determined by its size but also by its shape, composition, and structure, for instance if it's solid or hollow. A reliable manufacturing technology that makes use of nanocrystals' properties - for a wide-ranging number of applications in such areas as catalysis, electronics, photonics, information storage, imaging, medicine, or sensing - needs to be capable of churning out large quantities of nanocrystals where each batch is produced according to the exactly same parameters. In a recent review article, Sara Skrabalak from Indiana University and Younan Xia from Washington University in St. Louis, describe recent advances in seeded growth as the ultimate approach to producing metal nanocrystals with precisely controlled sizes, shapes, and compositions - the necessary first step toward their use and assembly for large-scale applications.... nanotechnology article
Quantum dots are emerging as an important class of nanoparticles with applications ranging from medicine to energy. These nanocrystals possess size tunable optical and electronic properties resulting from quantum confinement which allow them to be suitable candidates for applications in solar cells and light emitting devices. For instance, quantum dots have been identified as important light harvesting material for building highly efficient solar cells - when exposed to light at certain wavelengths they can generate free electrons and create an electrical current. Having a high resistance to photobleaching, quantum dots (QDs) also are attractive materials for optoelectronics and in vivo biosensing. Researchers have now demonstrated that QDs, in addition to being excellent fluorescent probes, can be used as photoacoustic (which combines the advantages of optical absorption contrast with ultrasonic spatial resolution for deep imaging) and photothermal contrast agents and sensitizers, thereby providing an opportunity for multimodal high resolution photoacoustic/photothermal-fluorescent imaging as well as sensitizers in nanotherapeutic applications.... nanotechnology article
The study of individual live cells is a hugely important scientific task and essential to the field of molecular biology and biomedical research. Among the most significant technical challenges for performing successful live-cell imaging experiments is to maintain the cells in a healthy state and functioning normally on the microscope stage while being illuminated. Especially if scientists want to look into cellular processes that occur inside cells in their natural state and that cannot be observed by traditional cytological methods. Quantum dots (QDs), also called nanocrystals, hold increasing potential for in vitro and in vivo cellular imaging. For instance, we have previously reported about how researchers have used QDs for in vivo imaging of embryonic stem cells in mice, a novel technique that has opened up the possibility of using QDs for fast and accurate imaging applications in stem cell therapy. The usefulness of quantum dots comes from their peak emission frequency's extreme sensitivity to both the dot's size and composition. QDs have been touted as possible replacements for organic dyes in the imaging of biological systems, due to their excellent fluorescent properties, good chemical stability, broad excitation ranges and high photobleaching thresholds.... nanotechnology article
