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Title: Self-assembly of DNA functionalized gold nanoparticles at the liquid-vapor interface

Here, surface sensitive synchrotron X-ray scattering and spectroscopy are used to monitor and characterize the spontaneous formation of 2D Gibbs monolayers of thiolated single-stranded DNA-functionalized gold nanoparticles (ssDNAAuNPs) at the vapor–solution interface by manipulating salt concentrations. Grazing incidence small-angle X-ray scattering and X-ray refl ectivity show that the noncomplementary ssDNA-AuNPs dispersed in aqueous solution spontaneously accumulate at the vapor–liquid interface in the form of a single layer by increasing MgCl 2 or CaCl 2 concentrations. Furthermore, the monoparticle layer undergoes a transformation from short- to long-range (hexagonal) order above a threshold salt-concentration. Using various salts at similar ionic strength to those of MgCl 2 or CaCl 2 such as, NaCl or LaCl 3, it is found that surface adsorbed NPs lack any order. X-ray fluorescence near total reflection of the same samples provides direct evidence of interfacial gold and more importantly a significant surface enrichment of the cations. Quantitative analysis reveals that divalent cations screen the charge of ssDNA, and that the hydrophobic hexyl-thiol group, commonly used to functionalize the ssDNA (for capping the AuNPs), is likely the driving force for the accumulation of the NPs at the interface.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [1] ;  [4] ;  [1] ;  [1]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States)
  2. Ames Lab., Ames, IA (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Argonne National Lab. (ANL), Argonne, IL (United States); Ames Lab. and Iowa State Univ., Ames, IA (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Advanced Materials Interfaces
Additional Journal Information:
Journal Volume: 3; Journal Issue: 16; Journal ID: ISSN 2196-7350
Publisher:
Wiley-VCH
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1343319