Magnetic studies of Co2+, Ni2+, and Zn2+−modified DNA double−crossover lattices

• Published in: Applied surface science Vol. 427; pp. 416 - 421
• Main Authors: Dugasani, Sreekantha Reddy, Oh, Young Hoon, Gnapareddy, Bramaramba, Park, Tuson, Kang, Won Nam, Park, Sung Ha
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2018
• Subjects: DNA lattice; Ferromagnetism; Magnetization; Metal ion; Squid; DNA lattice; Metal ion; Ferromagnetism; Squid; Magnetization
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.08.069

•Co2+, Ni2+, and Zn2+-modified DNA lattices are fabricated on a substrate.•Magnetic characteristics of divalent-metal-ion-modified DNA lattices are studied.•The magnetic measurement of the sample shows unique ferromagnetic characteristics.•The magnetic hysteresis suggests potential feasibility of use in memory devices. We fabricated divalent-metal-ion-modified DNA double-crossover (DX) lattices on a glass substrate and studied their magnetic characteristics as a function of ion concentrations [Co2+], [Ni2+] and [Zn2+]. Up to certain critical concentrations, the DNA DX lattices with ions revealed discrete S-shaped hysteresis, i.e. characteristics of strong ferromagnetism, with significant changes in the coercive field, remanent magnetization, and susceptibility. Induced magnetic dipoles formed by metal ions in DNA duplex in the presence of a magnetic field imparted ferromagnetic behaviour. By considering hysteresis and the magnitude of magnetization in a magnetization-magnetic field curve, Co2+-modified DNA DX lattices showed a relatively strong ferromagnetic nature with an increasing (decreasing) trend of coercive field and remanent magnetization when [Co2+]≤1mM ([Co2+]>1mM). In contrast, Ni2+ and Zn2+-modified DNA DX lattices exhibited strong and weak ferromagnetic behaviours at lower (≤1mM for Ni2+ and ≤0.5mM for Zn2+) and higher (>1mM for Ni2+ and >0.5mM for Zn2+) concentrations of ions, respectively. About 1mM of [Co2+], [Ni2+] and [Zn2+] in DNA DX lattices was of special interest with regard to physical characteristics and was identified to be an optimum concentration of each ion. Finally, we measured the temperature-dependent magnetic characteristics of the metal-ion-modified DNA DX lattices. Nonzero magnetization and inverse susceptibility with almost constant values were observed between 25 and 300K, with no indication of a magnetic transition. This indicated that the magnetic Curie temperatures of Co2+, Ni2+ and Zn2+-modified DNA DX lattices were above 300K.