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I‐Motif Nanospheres: Unusual Self‐Assembly of Long Cytosine Strands
Author(s) -
Zikich Dragoslav,
Liu Ke,
Sagiv Lior,
Porath Danny,
Kotlyar Alexander
Publication year - 2011
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201002213
Subject(s) - scanning tunneling microscope , electrostatic force microscope , polarizability , atomic force microscopy , materials science , nanotechnology , molecule , nanostructure , microscopy , chemical physics , crystallography , chemistry , optics , physics , organic chemistry
Abstract The synthesis and characterization of novel DNA structures based on tetraplex cytosine (C) arrangements, known as i‐motifs or i‐tetraplexes, is reported. Atomic force microscopy (AFM) investigation shows that long C‐strands in mild acidic conditions form compact spherically shaped nanostructures. The DNA nanospheres are characterized by a typical uniform shape and narrow height distribution. Electrostatic force microscopy (EFM) measurements performed on the i‐motif spheres clearly show their electrical polarizability. Further investigations by scanning tunneling microscopy (STM) at ultrahigh vacuum reveals that the structures exhibit an average voltage gap of 1.9 eV, which is narrower than the voltage gap previously measured for poly(dG)–poly(dC) molecules in similar conditions.