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Linear 1D arrays of Gold Nanoparticles on Smart Grids1-3

Gold on DNA Scheme

In this example, SMART TEM Grids were used as a platform for multi-step deposition and characterization of one-dimensional arrays of gold nanoparticles (AuNPs) to be used in nanoelectronics. Specifically, DNA strands deposited on the Hydrophobic Grid surface were used as biomolecular templates for the self-assembly of 1.5 nm AuNPs. In this system, the positive surface charge of AuNPs functionalized with quaternary ammonium is attracted to and self-assembles on the negative partial charge of phosphate groups in the DNA backbone. Electrical measurements were performed on the grids to determine the Coulomb blockade effect for these 1-D gold NP arrays.

This sample was prepared using a series of processing and characterization steps that illustrate the durability and unique features made possible by SMART Grids.

YOYO Dyed DNA

Fig 2. Fluorescent micrograph of DNA deposited on TEM grid surface. Sample was stained with YOYO-1 (Invitrogen) to determine distribution of DNA across SMART Grid surface.

  • Aggressive cleaning in oxygen plasma.
  • Hydrophobic surface chemical modification using corrosive reagent
  • Molecular combing and alignment of DNA4 as a biomolecular nanolithography template.
  • Deposition of functionalized AuNPs on DNA strands.
  • TEM imaging of 1D arrays of AuNPs.
  • Fluorescent imaging of grids and 1-D arrays.
  • Measurement of I-V response for coulomb blockade effect of 1D arrays of AuNPs.
long chain

Fig. 3 Bright field TEM image of 1.5 nm Au NPs deposited on DNA stretched across SMART Grid surface.

multitechnique analysis

Fig. 4 (left) Low magnification bright field TEM image of Au NPs deposited on DNA array aligned on SMART Grids surface. (middle) Close-up TEM image of branched bundle of DNA on grid surface. (right) AFM image of 1-D Au NP arrays deposited on DNA on SMART Grid Surface. The image was taken in tapping mode using the amplitude contrast.

References:

  • 1) Warner and Hutchison, Nature Mater. 2003, 272-277.
  • 2) Woehrle, Warner, Hutchison, Langmuir. 2004, 20, 5982
  • 3) Kearns, Foster, and Hutchison, Analytical Chemistry, Vol. 78, No. 1, January 1, 2006
  • 4) Bensimon et al. Science 1994, 265, 2096