Magnetic Manipulation of Nucleic Acid Base Microcrystals for DNA Sensing

This paper develops a magneto-DNA sensing device composed of a crystalline nucleic acid base, which is a component of DNA on the basis of the dynamic rotation due to its diamagnetic anisotropy under a magnetic field of the mT order. As a basic study, recrystallized nucleic acid bases, such as cytosine, adenine, and guanine, were used for the measurement. We focused on the induced dynamic orientation effect on the nucleic acid base crystals by exposure of the magnetic field at 0.5 T. The morphologically long axis of a cytosine crystal oriented parallel to the applied magnetic fields, while those of adenine and guanine oriented perpendicular to the magnetic field. As a next stage, we traced the angular difference of the magnetic rotation of DNA adhered to guanine crystals comparing the rotation angles of the pre-exposure sample and the during exposure sample with and without DNA. It was revealed that the degree of the magnetic rotation of guanine crystals with DNA was seemingly less than that of guanine crystals without DNA. The difference in angle of the magnetic rotation of the guanine crystal may allow to detect the adhesion of DNA. The method obtained by detecting precise magnetic rotation of nucleic acid base crystals can be applied to the manipulation and sensing of macromolecules in dispersion containing nucleic acid bases, such as DNA and RNA.