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#Scientists Demonstrate Intrinsic Chirality in Ordinary Nanocrystals By Stuart Milnethese findings have opened new possibilities in medicine, biotechnology and nanobiotechnology for applications including targeted drug delivery. Chirality of an object is its property that allows it to be non-superimposable with its mirror image. Ever since the development of artificial nanocrystals, scientists thought that chirality was either random or completely absent in nanocrystals. Researchers from Trinity college Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), partnered with collaborators from ITMO University Optics of Quantum Nanostructures laboratory in a joint experiment to show that standard nanocrystals were made up a 50:50 mixture of'left'and'right'chiral forms. Standard nanocrystals are composed of cadmium selenide quantum dots and quantum rods. Artificial chiral nanocrystals can be produced by fastening special chiral ligand molecules to the nanocrystal surface. In the natural world, chirality is an inherent property of many objects that range from spiral galaxies to elementary particles. The human body is composed of chiral biomolecules. Many other biological objects are composed also of these chiral biomolecules. In these compounds, the'left'form may be significantly different from the'right'form. Among these forms, usually one form is beneficial, which could be medical benefits, while the other form, which is its antipode, would be useless. Ibuprofen is used a widely painkiller and its molecules possess two optical mirror isomers. One of these isomers is beneficial and relieves the pain, while the other is toxic and does not relieve pain. The optical activity is considered to be an important indicator of chiral environment. It has the ability to rotate the polarized light plane to the left or right, depending upon the nanocrystal chiral form. Theoretically, optical activity is observed not in any normal nanocrystal solution. The absence of chirality in nanocrystals has been considered to be the cause of optical activity. In this study, the researchers have proved the opposite, by dividing the nanocrystal'left'and'right'forms. Yurii Gun'ko, professor at Trinity college and co-director of International Research and Education Centre for Physics of Nanostructures at ITMO University comments on potential applications of the method developed by the group: The scientists developed a technique for separating various forms of nanocrystals and also capture their intrinsic chirality manifestation. This technique could possibly be expanded and then used with various other inorganic nanomaterials. In an unmixable two-phase solution composed of an organic solvent (chloroform) and water, nanocrystals were immersed. Nanocrystals do not dissolve in water; hence L-cysteine was added to transfer the nanocrystals in organic phase to water. L-cysteine is a chiral molecule and it is used widely for phase transfers as a ligand. Nanocrystals have hydrophobic ligands on their surface, and cysteine replaces these ligands and makes the material soluble in water. Hence, all the nanocrystals will be in water, irrespective of the cysteine chiral form. When this solution was cooled and the phase transfer was interrupted at a specific point, a particular situation where the nanocrystal ensemble was divided equally between the phases that had nanocrystals both'left'and'right'-in different phases. Furthermore removal of cysteine does not affect the nanocrystal optical activity due to this separation. This provides more proof to the existence of intrinsic chirality in nanocrystals. Vladimir G. Maslov, Anatoly V. Fedorov, Alexander V. Baranov, Finn Purcell-Milton, Anna O. Orlova, and Joseph Govan were other researchers who took part in this study. The research team has published their study titled,'Intrinsic chirality of Cdse/Zns quantum dots and quantum rods,'in Nano Letters e

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