Abstract
Synthetic guanine crystals, with the same magnetic controllable reflection property as a biogenic guanine crystal from fish scales, were prepared using a classical Ostwald ripening method for crude crystals, from the aqueous sodium hydroxide solution of a commercially available synthesized guanine powder. The resulting synthetic guanine crystals with an average size of several tens of micrometers were in the same crystal system as the biogenic guanine crystals under measurement by X-ray diffraction (XRD). However, XRD patterns of water-floating crystals showed that the correlation between the growing direction and reflecting surface in the synthetic crystals is different from that in the biogenic crystals. Therefore, the synthetic crystals were ground by an agate mortar for refinement of its optical and magnetic-orientation characters. As a result, we realized a fast-magnetic orientation against the vertical field, which is related to the magnetic control of light reflection, the same as the biogenic guanine crystal behavior.
Highlights
Guanine, which is a simple molecule with a molecular weight of only 151, is one of the most important molecules for the manipulation of light in living system.1–8 There is a possibility that the use of guanine crystals may lead to a novel micro optical device with a higher ordered function, such as an artificial iridosome or a material exhibiting structural color
The crude crystals with an average size of 10 μm were boiled at ca. 100 ○C in an aqueous sodium hydroxide solution at pH 13 to increase the crystal size in a classical Ostwald ripening condition over one week
For X-ray diffraction (XRD) measurements, two types of samples were prepared for both the synthetic guanine crystal and the biogenic guanine crystal from the scales of a goldfish
Summary
Guanine, which is a simple molecule with a molecular weight of only 151, is one of the most important molecules for the manipulation of light in living system. There is a possibility that the use of guanine crystals may lead to a novel micro optical device with a higher ordered function, such as an artificial iridosome or a material exhibiting structural color. We reported that biogenic guanine crystals can be used as micro optical devices that can control the reflection characteristics by using the external magnetic field response accompanied by the anisotropy of the diamagnetic susceptibility of guanine crystals.. Guanine crystals that can be used as magnetic switchable reflectors can only be collected from living creatures, such as fish, because the shape and size of synthetic guanine crystals prepared using an artificial method are much poorer than those of biogenic crystals. A notable reason for the difficulty in the preparation of synthetic guanine crystals by an artificial method is the low water-solubility.. The resulting synthetic guanine crystals have the same crystal structure as that of biogenic guanine crystals, but these external shapes are insufficient for use in magnetic switching optical devices, as described above. Crystallographic information of the crystals, which were dried or floating in water, was obtained by using an XRD analysis
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
