72549097 DNA origami has helped to create self assembling material Invisibility
Scientists have developed a new principle for the creation of metamaterials, which uses the technology of DNA origami. Article researchers have not yet been accepted for publication in a peer-reviewed scientific journal, but it is a preprint available at arXiv.org. The properties of metamaterials depend primarily on their structure, rather than on the chemical composition. These materials are capable of in a special way to bend the light path – in particular, they can be used to make objects invisible to the observer in a certain range of frequencies. This effect is due to the fact that radiation is directed metamaterial bends around so masked object that its image formed by reflected rays, not reaching the detectors. Feature masking objects using metamaterials is that their regular structural features (for example, in some way arranged pins or holes) must be less than the wavelength of the radiation, for which "works" given the metamaterial. It is for this reason, most of the created on date of metamaterials not suited for visible light (380 to 740 nanometers), while for radiation with a longer wavelength. To metamaterials "worked" for visible light, the characteristic size of their regular structures should be several nanometers. A separate challenge is the creation of metamaterials, arranged not according to the carpet-invisible (ie, two-dimensional), and the full three-dimensional devices (such devices are more versatile in use). The authors of a new attempt to overcome both these obstacles, using the technology of DNA origami – to create complex structures of segments of DNA. This biopolymer has the property of complementarity – segments of DNA with a specific sequence of "letters" form with each other strong connections – and, properly chosen sequence of "letters", scientists can "make" the necessary structures to assemble themselves. Scientists collected complex structures using gold nanoparticles with attached DNA segments that are "found" them complementary pairs contained on the skeleton. Nanoparticles are lined up on the frame, attaching to it by forming base pairs between the strands of DNA. As a result of DNA "pins" formed a regular structure that has given optical properties. In the future, developed by researchers at the principle of creating metamaterials – which are, rather, "metazhidkost", since all the components are floating in the solution – will create materials that make invisible objects in the visible wavelength range. Recently, another group of researchers presented papers In which the step was taken to eliminate the inconvenience of yet another stealth – despite the fact that the characteristic size of the regular structures must be very small, the size of the masking device is much larger than the masked object. Accordingly, the masking of relatively large objects associated with significant complications. A group of scientists suggested a way around this difficulty.
