title: Construction and characterization of Cu²⁺, Ni²⁺, Zn²⁺, and Co²⁺ modified-DNA crystals.
abstract: We studied the physical characteristics of modified-DNA (M-DNA) double crossover crystals fabricated via substrate-assisted growth with various concentrations of four different divalent metallic ions, Cu(2+), Ni(2+), Zn(2+), and Co(2+). Atomic force microscopy (AFM) was used to test the stability of the M-DNA crystals with different metal ion concentrations. The AFM images show that M-DNA crystals formed without deformation at up to the critical concentrations of 6 mM of [Cu(2+)], 1.5 mM of [Ni(2+)], 1 mM of [Zn(2+)], and 1 mM of [Co(2+)]. Above these critical concentrations, the M-DNA crystals exhibited deformed, amorphous structures. Raman spectroscopy was then used to identify the preference of the metal ion coordinate sites. The intensities of the Raman bands gradually decreased as the concentration of the metal ions increased, and when the metal ion concentrations increased beyond the critical values, the Raman band of the amorphous M-DNA was significantly suppressed. The metal ions had a preferential binding order in the DNA molecules with G-C and A-T base pairs followed by the phosphate backbone. A two-probe station was used to measure the electrical current-voltage properties of the crystals which indicated that the maximum currents of the M-DNA complexes could be achieved at around the critical concentration of each ion. We expect that the functionalized ion-doped M-DNA crystals will allow for efficient devices and sensors to be fabricated in the near future.
authors.affiliation: Department of Physics, Sungkyunkwan University, Suwon 440-746, Korea. Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746, Korea.
authors.forename: Sreekantha Reddy
authors.initials: SR
authors.lastname: Dugasani
authors.forename: Myoungsoon
authors.initials: M
authors.lastname: Kim
authors.forename: In-yeal
authors.initials: IY
authors.lastname: Lee
authors.forename: Jang Ah
authors.initials: JA
authors.lastname: Kim
authors.forename: Bramaramba
authors.initials: B
authors.lastname: Gnapareddy
authors.forename: Keun Woo
authors.initials: KW
authors.lastname: Lee
authors.forename: Taesung
authors.initials: T
authors.lastname: Kim
authors.forename: Nam
authors.initials: N
authors.lastname: Huh
authors.forename: Gil-Ho
authors.initials: GH
authors.lastname: Kim
authors.forename: Sang Chul
authors.initials: SC
authors.lastname: Park
authors.forename: Sung Ha
authors.initials: SH
authors.lastname: Park
mesh_terms: D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D019216:Metals, Heavy / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
chemical_list: D019216:Metals, Heavy; D004247:DNA