I-motif nanospheres: Unusual self-assembly of long cytosine strands

Dragoslav Zikich, Ke Liu, Lior Sagiv, Danny Porath*, Alexander Kotlyar

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


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.

Original languageEnglish
Pages (from-to)1029-1034
Number of pages6
Issue number8
StatePublished - 18 Apr 2011


  • DNA
  • atomic force microscopy
  • i-motifs
  • nanostructures
  • self-assembly


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