title: Use of the interparticle i-motif for the controlled assembly of gold nanoparticles.
abstract: In this letter, we present a new design that uses single-stranded (ss) DNAs containing two stretches of cytosine (C)-rich domains for the controlled assembly of gold nanoparticles (Au NPs). We show that this assembly is driven by the formation of interparticle i-motif (four-stranded C-quadruplex) structures formed between the C-rich domains of the ssDNAs on neighboring Au NPs. The assembly happens only at slightly acidic pH conditions (pHs below the pKa of the i-motif). The assembly is reversible and can be switched by changing the solution pH. The assembly and disassembly process is accompanied by distinct color changes that are clearly visible to the naked eye. This development may have applications in the controlled assembly of reversible pH-sensitive nanostructures and/or devices.
authors.affiliation: National Centre for Nanoscience and Technology, No. 2 First North Street, Zhongguancun, Beijing 100080, PR China.
authors.forename: Wenxing
authors.initials: W
authors.lastname: Wang
authors.forename: Huajie
authors.initials: H
authors.lastname: Liu
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Liu
authors.forename: Yun
authors.initials: Y
authors.lastname: Xu
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Dejian
authors.initials: D
authors.lastname: Zhou
mesh_terms: D003596:Cytosine / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009690:Nucleic Acid Conformation; D010316:Particle Size; D013053:Spectrophotometry; D013499:Surface Properties; D013997:Time Factors
chemical_list: D004277:DNA, Single-Stranded; D006046:Gold; D003596:Cytosine