Transcript Self-Assembly at nano-Scale Binary Nanoparticles Superlattices

Dip-Pen Nanolithography (DPN)
•
DPN is a direct-write scanning-probe-based lithography in
which an AFM tip is used to deliver chemical reagents directly
to nanoscopic regions of a target substrate
•
Components:
Pen: AFM scanning cantilever
Ink: the materials that bind to the surface
Paper: Substrate such as Au, SiOx, mica
Figure 1. Schematic
representation of the
DPN process. A water
meniscus forms
between the AFM tip
which is coated with
“ink” molecules
and the solid substrate
Direct-Write DNP procedure
• Prepare the ink
(Fe2O3nanoparticles hydrosol)
• Prepare the paper (mica &
silicon, surface treatment by
aqueous HF solution)
• Coat the cantilever with the
ink
• Scan the area for patterning
in the contact mode, with a
slower scan rate, 1 µm s-1
• For AFM characterization,
use the same AFM, scan it at
higher scan rate, 10 µm s-1
Direct-Write DNP for protein array
• Prepare the ink (MHA:
mercaptohexadecanoic acid)
• The paper (silicon slides)
• Coat the cantilever with the ink
• Scan the area for patterning in
the contact mode.
• Protein adsorption (rabbit IgG )
• antibody recognition.
• The resulting protein arrays
were then characterized by
AFM. B) Topography image of
the protein array
Direct-Write DNP for protein array
Height profiles of TMAFM images: rabbit IgG
assembled on an MHA
dot array generated by
DPN before (A) and
after (B) treatment with a
solution containing
lysozyme, goat/sheep
anti-IgG, human anti-IgG,
and rabbit anti-IgG; a
control protein
nanoarray before (C)
and after (D) exposure
to a solution containing
lysozyme, retronectin,
goat/sheep anti-IgG, and
human anti-IgG.
Nanostructures patterned by DPN
A) Nanoscale dot arrays and B) nanoscale letters written on a Au surface
C) TM-AFM image of 25- and 13-nm gold nanoparticles hybridized to surface DNA
templates generated with DPN D) Fluorescence image of DPN patterns
of fluorescently labeled IgG on SiOx
Nanostructures patterned by DPN
B) TM-AFM image of 60-nm gold nanolines C)12-nm gold nanogap on a Si/SiOx
surface. D) 3D Si(100) nanostructures. TM-AFM image of DNA-modified line (E),
features after hybridization with complementary DNA-modified nanoparticles; inser
high-resolution TM-AFM images
Advantages
It might be the only lithographic technique that offers
• High resolution
• High registration
• With direct-write printing capabilities
Limitation of the method
More efforts should be put in improving
the speed and in transforming it into
massively parallel process to be a
powerful production tool in both the life
science and the semiconductor industry.
Conclusions
• DPN is a unique scanning-probe-based lithographic tool for
generating high-resolution patterns of chemical functionality
on a nano range of surfaces.
• The combination of resolution, registration, and direct-write
capability offered by DPN distinguishes it from any
alternative lithographic strategy and makes DPN a
promising tool for patterning soft organic and biological
nanostructures.